Donor age is an important predictor for liver transplant recipients. Studies have not fully explored its impact on transplant outcomes in hepatocellular carcinoma (HCC) patients as well as its involvement in tumor recurrence.HCC patients who received liver transplants during 2010–2017 from the Scientific Registry of Transplant Recipients database were included. The recipients were divided into four groups based on donor age: I (≤ 34 years), II (35–49 years), III (50–64 years), and IV (≥ 65 years). Transplant outcomes, including the overall survival (OS), tumor recurrence, and risks, were evaluated.P < 0.001). However, the liver-specific survival did not differ among these groups (P = 0.260). Donor age was found to be the independent predictor of OS after adjusting for other variables  for group II, P = 0.119; 1.124 (1.015–1.246) for group III, P = 0.025; 1.395 (1.215–1.602) for group IV, P < 0.001). In subgroup analysis, OS was significantly different in recipients with hepatitis C virus (HCV), but there was no significant difference for recipients with hepatitis B virus (HBV), alcoholic liver diseases and nonalcoholic steatohepatitis (NASH). The post-transplant cumulative tumor recurrence rates were similar among the four groups (P = 0.382).A total of 13,276 HCC recipients were included in this study. Statistical significant differences were observed in OS among the four groups. The best 5-year survival was 76.0% in group I, followed by 73.5% in group II, 72.8% in group III, and 69.2% in group IV (Older donor age was associated with decreased OS but not liver-specific survival as well as post-transplant tumor recurrence in HCC recipients. Donor age also had different effects in patients with different underlying liver diseases.The online version contains supplementary material available at 10.1186/s12876-021-01786-6. Hepatocellular carcinoma (HCC), the fourth most common cause of cancer-related death worldwide, accounts for more than 700,000 deaths annually and its incidence continues to increase –3. Only Marginal donor usage has been suggested to expand the donor pool. Older donors are the most commonly used marginal donors. The number of older liver donors is increasing due to the ageing population . HoweverDespite this, the effect of donor age on liver transplantation specifically in HCC patients has not yet been fully elucidated. Tumor recurrence after liver transplantation is an important concern in those patients. We have already established recipient selection criteria so that donors are matched with the most feasible patients to obtain favorable post-transplant outcomes , 9. HoweHere, we use renewed data from the SRTR database to evaluate the effect of donor age on liver transplant outcomes, especially OS and tumor recurrence, in patients with HCC.This study used data from the Scientific Registry of Transplant Recipients (SRTR). The SRTR data system includes data on all donor, wait-listed candidates, and transplant recipients in the US, submitted by the members of the Organ Procurement and Transplantation Network (OPTN). The Health Resources and Services Administration (HRSA), U.S. Department of Health and Human Services provides oversight to the activities of the OPTN and SRTR contractors. The data reported here have been supplied by the Hennepin Healthcare Research Institute (HHRI) as the contractor for the Scientific Registry of Transplant Recipients (SRTR). The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy of or interpretation by the SRTR or the U.S. Government . Organs We included patients with HCC who received liver transplantation from January 1, 2010, to December 31, 2017. The inclusion criteria were: recipients ≥ 18 years old, with a primary diagnosis of “hepatocellular carcinoma” or “hepatoma” at transplant. Patients with a previous liver transplantation, those who received transplant for benign liver disease or liver tumor other than HCC, and those < 18 years old were excluded from this study. Finally a total of 13,276 recipients were included in the current study. Patients were followed up to death or the end of the study on 1st March, 2019. Figure To assess how donor age affects transplant outcomes, we divided recipients into four groups according to donor age: group I, donor age ≤ 34 years (N = 4723); group II, donor age 35–49 years (N = 3572); group III, donor age 50–64 years (N = 3743); group IV, donor age ≥ 65 years (N = 1238). The donor and recipient data as well as tumor characteristics were compared among the four groups.For long-term outcomes, we first compared post-transplant OS among four groups, which was evaluated from the time of LT and defined recipient death as the endpoint. OS was also assessed based on recipient underlying liver diseases including hepatitis C virus (HCV), hepatitis B virus (HBV), alcoholic liver diseases and nonalcoholic steatohepatitis (NASH). Liver-specific survival was also analyzed, which was measured from the date of LT to date of liver-related death or last follow-up. Patient cause of death, including graft failure, cardiovascular/cerebrovascular disease, organ failure, hemorrhage, infection and HCC recurrence, were compared among the four groups, first within 30 days after transplantation and then for the whole population. The post-transplant HCC recurrence was compared among the four groups, and the definition was in accordance with the report by Samoylova et al. . The detP < 0.05 were further analyzed in the multivariable analysis using the Cox proportional hazard ratios (HRs) model. Time-dependent effects were evaluated based on Schoenfeld’s residuals, and cubic spline functions were introduced in the model [Baseline characteristics were compared using one-way ANOVA for continuous variables and the chi-square test for binomial variables. OS and liver-specific survival was assessed by the Kaplan–Meier method and log-rank test was used to compare differences among the groups. Univariate analysis was used to identify potential predictors for OS, and those with he model . The cumThe median follow-up time was 36 months  for the entire study population. Donor characteristics including donor height, weight, race, ABO blood type, sex, cause of death, deceased donor type (DCD or not) significantly differed among the four groups. For recipient characteristics, the recipient age, race, ABO blood type, underlying liver disease, height, weight, cold ischemia time, body mass index (BMI), laboratory model for end-stage liver disease (MELD) score, albumin, bilirubin, international normalized ratio (INR), creatinine and immunosuppression maintenance with tacrolimus, cyclosporin, mycophenolate mofetil and steroids at discharge were all statistically different among the four groups. However, the recipient warm ischemia time, pre-transplant sodium level and immunosuppression induction (with anti-CD25 or thymoglobulin) as well as sirolimus maintenance at discharge were comparable among the four groups. Analysis of tumor characteristics revealed that the pre-transplant treatment , radiofrequency ablation (RFA), chemotherapy, cryoablation, surgery), number of tumors, largest tumor diameter, sum of tumor diameters, tumor staging, and pre-transplant α-fetoprotein (AFP) level were all similar among four groups. Table P < 0.001; Fig. P = 0.049; group I vs. group III, P = 0.002; group I vs. group IV, P < 0.001). The survival of group II recipients was comparable to that of group III (P = 0.308) but significantly better than that of group IV recipients (P = 0.004). The survival of group III recipients was also better than group IV (P = 0.038). We also compared OS after excluding patients whose follow-up time was < 24 months, and observed similar outcomes , organ failure (P = 0.002) and infection (P = 0.001) in the older donor age group during follow-up . The median time to recurrence after transplantation was 22 months  in group I, 22.5 months (12–35 months) in group II, 21.5 months (12–35.5 months) in group III and 22 months (11–37 months) in group IV. To further analyze the cumulative tumor recurrence rates, we introduced the competing risk model. We observed that the cumulative recurrence rates in the four groups were also similar, with a 5-year cumulative recurrence rate of 5.54% in group I, 4.98% in group II, 4.80% in group III and 5.84% in group IV .The general tumor recurrence rates were comparable among the four age groups (218 (4.6%) in group I, 142 (4.0%) in group II, 150 (4.0%) in group III and 57 (4.6%) in group IV, As no difference was observed in terms of recurrence rates among the groups, additional Cox regression model and competing regression model were not used. However, we further investigated the time-dependent effect of donor age on tumor recurrence in a sensitive analysis. The effect of donor age also remained generally stable in the early transplant years, and showed a decreasing trend over the long-term follow-up period (Additional file In this study, we demonstrated that the OS differed in HCC liver transplant recipients categorized according to different donor ages, whereas donor age had no effect on post-transplant tumor recurrence. With regard to underlying liver diseases, there were differences in OS in HCV recipients, but not in recipients with HBV, alcoholic liver diseases or NASH.The impact of donor age on transplant outcomes has been evaluated for decades with controversies surrounding the safety and feasibility of grafts from older donors. Some studies revealed the association between older donor age and decreased recipient survival while others shared successful experience of the use of septuagenarian and even octogenarian donors , 15–17. We found that there were significant statistical differences in OS among four age groups, while no difference was observed with regard to tumor recurrence. Indeed the actual survival differences were minimal among four groups, especially at post-transplant 1 year. The significant statistical difference in OS might be due to the large cohort of patients included in this study, which might not necessarily mean clinical relevance. Moreover, the liver-specific survival was similar among four groups, which might indicate that older donor age had minimal impact on liver graft to affect long-term survival in HCC recipients.We also observed the differential effects of donor age on recipients with different underlying liver diseases. In patients with HCV, older donor age was associated with decreased OS, while in patients with HBV, alcoholic liver diseases and NASH, no differences in OS were observed among four groups. This result is in accordance with that reported by Lake et al. , who repRecipient age was also found to be an independent predictor of OS in HCC recipients, which was in accordance with previous literature –26. PatiOur study has several limitations. First, as it is based on a large dataset, we could not analyze the possible confounding variables such as tumor biology as assessed by Edmondson-Steiner grade and microvascular invasion, which are important predictors for overall survival and tumor recurrence in HCC patients. Also, variables related to new therapeutic advances in HCC treatment, such as the use of targeted therapies before or after transplantation, were also not available in the database. This is important because the prognosis of HCC patients has considerably improved in recent years with the development of targeted therapy and immunotherapy. Secondly, as our study included recipients from 2010 to 2017, there was a potential that a relatively short follow-up would confound the true risk of tumor recurrence after transplantation, especially with the currently ongoing development of new treatments for HCC, which might delay or diminish the recurrence of HCC. Nonetheless, our study presents the largest study to date to evaluate the effect of donor age on HCC patients based on the latest transplantation recipient cohort. In the future, prospective studies with long follow-up time need to be designed to investigate the effect of donor age in a more detailed manner to expand the donor pool and benefit more candidates on the waiting list.Our study demonstrated that although older donor age was associated with statistical inferior OS in transplant recipients with HCC, the actual survival differences were minimal. Moreover, older donor age was not correlated with decreased liver-specific survival as well as post-transplant tumor recurrence, which might indicate that it had minimal impact on long-term outcomes. For different underlying liver diseases, older donor age was associated with inferior OS in recipients with HCV but with no influence in recipients with HBV, alcoholic liver diseases or NASH. These findings may be useful for clinicians in decision-making with regards to marginal donor allocation and recipient selection to achieve favorable transplant outcomes.Additional file 1:  Table S1 - S6.Additional file 2: Figure S1. Overall survival of HCC recipients with post-transplant follow-up time ≥ 24 months categorized by different donor age groups.Additional file 3: Figure S2. Liver-specific survival of HCC recipients categorized by different donor age groups.Additional file 4: Figure S3. Overall survival of HCC recipients with post-transplant follow-up time ≥ 24 months in different donor age groups according to underlying liver diseases: a HCV; b HBV; c alcoholic liver diseases; d NASH.Additional file 5: Figure S4. Liver-specific survival of HCC recipients in different donor age groups according to underlying liver diseases: a HCV; b HBV; c alcoholic liver diseases; d NASH.Additional file 6: Figure S5. Overall survival between HCC recipients with and without post-transplant tumor recurrence.Additional file 7: Figure S6. Cumulative HCC recurrence rates categorized by different donor age groups.Additional file 8: Figure S7. Cox-derived estimates of the time-dependent hazard ratio of donor age for HCC recurrence after liver transplantation.


Streptococcus milleri (SM) is often complex and requires a combination of surgery and intravenous (IV) antibiotics. There is a paucity of data on the efficacy of oral (PO) treatment due to concerns about the development of resistance, particularly to fluoroquinolones (FQ). We report outcomes of postoperative antibiotic treatment for SM empyema over 3 years, including PO therapy. Pleural empyema from SM diagnosed by thoracentesis or operative culture. We reviewed clinical factors, route and duration of antibiotics, complications , and mortality (30-day and 1-year) A single-center retrospective chart review was performed of 20 patients treated with video-assisted thoracoscopic surgery (VATS) from October 2015 to March 2018 and < 0.19 μg/mL Of the 20 patients, 12 (60%) received all IV and 8 (40%) transitioned to PO therapy (Table 1). Median age was 60 and 58 in the IV and PO group, respectively. IV treated patients had more comorbidities. Cultures were primarily monomicrobial. Isolates tested were susceptible (S) to penicillin (Table 1), Of 10 tested specimen, all had moxifloxacin MIC MSSA endocarditis). There were no complications or deaths in patients treated PO. and 8/8 specimens tested were S to levofloxacin. The average duration of antibiotic therapy in the IV group was 34 days and 32 days in the PO group. There were no complications in the IV group: however, there were 2 deaths (1 patient died from comorbid complications and 1 patient was readmitted and died due to SM in certain patients. FQs have been generally avoided due to concerns about the rapid development of resistance that has been shown in-vitro; however, no in-vivo data have been reported regarding this concern. We show excellent outcomes with the use of PO therapy in susceptible isolates, particularly FQs, with no failure or reported resistance in patients with SM empyema treated with VATS. Further study is needed to validate these findings and determine optimal patient characteristics for transition to PO therapy. Our review suggests that early transition to PO antibiotics may be a viable option for operatively managed empyema caused by All Authors: No reported disclosures


Most of childhood hydrocephalus are originating during infancy. It is considered to be a complex disease since it is developed on the basis of heterogeneous pathophysiological mechanisms and different pathological conditions as well as during different age groups. Hence, it is of relevant importance to have a practical concept in mind, how to categorize hydrocephalus to surgically better approach this disease. The current review should offer further basis of discussion on a disease still most frequently seen in Pediatric Neurosurgery. Current literature on pathophysiology and classification of pediatric hydrocephalus has been reviewed to integrate the different published concepts of hydrocephalus for pediatric neurosurgeons. The current understanding of infant and childhood hydrocephalus pathophysiology is summarized. A simplified concept based on seven factors of CSF dynamics is elaborated and discussed in the context of recent discussions. The seven factors such as pulsatility, CSF production, major CSF pathways, minor CSF pathways, CSF absorption, venous outflow, and respiration may have different relevance and may also overlap for the individual hydrocephalic condition. The surgical options available for pediatric neurosurgeons to approach hydrocephalus must be adapted to the individual condition. The heterogeneity of hydrocephalus causes mostly developing during infancy warrant a simplified overview and understanding for an everyday approach. The proposed guide may be a basis for further discussion and may serve for a more or less simple categorization to better approach hydrocephalus as a pathophysiological complex disease. Hydrocephalus is a condition of CSF circulation disturbance with imbalanced CSF flow dynamics of various reasons and develops as a symptom of an underlying disease. According to our database of more than 500 primary surgeries, more than 60% of pediatric hydrocephalus need their first surgical treatment during infancy, while approximately 74% of shunted patients have received surgery during infancy at an age younger than 24 months [unpublished data]. The causes of hydrocephalus are heterogeneous such as the pathophysiologic mechanism leading to disturbed CSF flow. Many authors have previously described how to classify hydrocephalus which led to different concepts , 61, 65.Rekate and colleagues described the hydraulic circuit of CSF as a continuum of the arterial inflow; the CSF production; the CSF flow along the ventricles, cisterns, spinal, and cranial subarachnoid space; and finally the venous outflow . One relAdditional anatomic relevant structures are the correlates of CSF production and CSF absorption. Those have also been discussed extensively, and it turned out that both mechanisms are based on a variety of anatomical structures , 57, 62.Also, the foramen magnum seems to be relevant for balancing any pulsation from the cranial space toward the spinal canal since the calvarium represents a firm cavity without any ability to balance out pulsatile activity externally while the spinal canal’s dura is surrounded by epidural fat, which enables elasticity and a thus offers a “Windkessel” function to somehow flatten the pulsatile curve .Theories of hydrocephalus development due to increased pulsatility and decreased compliance have first been indicated by Di Rocco, who inserted a cardiac rhythm synchronized pulsating balloon in the ventricle, which resulted in ventricular enlargement without direct occlusion of any major CSF pathways . The intRecent advances in MR imaging have enabled to investigate CSF flow within different anatomical levels of the CSF space. Initially, CSF pulsation sequences directed a lot of intention toward pulsatile flow characteristics within the Sylvian aqueduct . FurtherOreskovic has questioned any net CSF flow at the aqueduct level after performing the cannulation of the aqueduct and connecting the tube to an external drain and failing to observe any drainage of CSF through the cannula at the same level of the aqueduct . This faThe absorption of CSF takes place through different anatomical correlates of venous outflow and lymphatic system. Any venous congestion due to different reasons of pulmonary hypertension, right heart failure, venous outflow stenosis, or cranial constriction, has direct consequences on CSF dynamics. The venous absorption is impaired, but in parallel, the intracerebral blood volume is increased. Classically, the idiopathic intracranial hypertension, formerly known as pseudotumor cerebri, is associated with increased intracranial pressure with narrow ventricles , 53, 76.Developmental aspects are well known to contribute to understanding of CSF physiology. The choroid plexus develops in the embryo, but CSF did already exist being produced in capillary fluid exchange of other origin . MoreoveDifferent theories have been defined how hydrocephalus may develop. In recent years, older theories are challenged, and additional explanations are made in order to understand the unified theory for the pathophysiology of developing hydrocephalus. However, it might not be relevant to identify the one and only theory but rather to understand the complex nature of CSF circulation disturbances and respect the different natures of disturbances which will lead to the individual hydrocephalic condition. On the basis of the hydraulic circuit by Rekate, the interaction between blood flow and CSF circulation are described . The modWithin the seven factors, the activity of the heart, which is transmitted by the arteries into the intracranial space and the parenchyma, is determining the main pulsatile movement in the CSF (I). Based on DiRocco and according to Greitz and Preuss , 28, 61,In contrast to a rather complex classification of pathophysiology, the therapeutic options we apply as pediatric neurosurgeon are rather limited but are still a challenge to apply in the optimal way. Temporary and permanent treatment options of hydrocephalus are distinguished Fig. .Fig. 3OvAmong temporary treatment options, there are CSF punctures, external ventricular drainage, ventricular access device, or ventricular subgaleal shunt. For CSF puncture, transfontanelle puncture is reserved for emergency situations and becomes obsolete due to higher rate of infectious complications . Lumbar Permanent hydrocephalus treatment consists of shunting, endoscopic procedures, or both may be combined. Shunt procedures still account for the vast majority of permanent hydrocephalus treatments, and ventricular peritoneal shunting is used most frequently. Alternatives such as ventricular arterial shunts or others are used when the resorption capacity of the peritoneum is impaired due to e.g., peritonitis or necrotizing enterocolitis in the neonates. Subdural-peritoneal shunts are used in hygroma-associated CSF circulation disturbances and may need removal or conversion into VP shunt if hydrocephalus persists. Cystoperitoneal shunts should be avoided since almost all cysts do not represent a hydrocephalic condition but rather a problem of CSF isolated compartments, which should be broad in communication with regular CSF spaces by endoscopy or microsurgery , 38. LumAmong endoscopic techniques, ETV is well established in non-communicating hydrocephalus to reestablish communication between internal and external CSF spaces but may not be used under the age of 6 months due to higher failure rates. Especially in North America and Africa, ETV is combined with choroid plexus coagulation to enhance the success rate and avoid shunting , 67. ThiPediatric hydrocephalus is a complex disease, and deep knowledge is necessary to better understand each individual problem we are facing in our routine clinical work. The described seven categories of pathophysiology is a practical approach which might be applied for each patient in order to better understand the individual condition of hydrocephalus. Those may be existent alone or more often in combination in different types of hydrocephalus. Those will also help to better apply the optimal surgical treatment. Further research, however, is still of utmost importance to develop better protocols to reduce complication rates over time and enhance the neurocognitive outcome of our patients.


However, when the onset age was >38.5 years, both IgG index with the threshold of 0.8 and CSF-OCB were moderately consistent with the diagnosis . In total, our optimized algorithm had the sensitivity, specificity, and predictive accuracy of 0.778, slightly outperforming the CSF-OCB model. Accordingly, a combination of the onset age and IgG index could serve as an alternative to CSF-OCB for differentiating between RRMS and NMOSD in Chinese patients.As the oligoclonal band in the cerebrospinal fluid (CSF-OCB) in predicting relapsing-remitting multiple sclerosis (RRMS) is less sensitive in Asian populations than that in westerners, it remains elusive whether the IgG index could serve as an alternative. The purpose of this study was to compare these two methods of differentiating between RRMS and neuromyelitis optica spectrum disorder (NMOSD) in Chinese patients. A total of 171 patients (81 RRMS and 90 NMOSD) were retrospectively recruited, of whom 82 (56 RRMS and 26 NMOSD) received the CSF-OCB testing additionally. When the onset age was ≤38.5 years, IgG index with the threshold of 0.67 had a significant agreement ( The presence of “oligoclonal bands” (OCBs) in the cerebrospinal fluid (CSF) has been identified as a key immunodiagnostic biomarker for multiple sclerosis (MS), detected in about 95% of clinically definite cases in western countries ,2. CSF-OAlthough previous studies have noted that the IgG index is less sensitive than the CSF-OCB by IEF in predicting MS ,4,8,9 anAccordingly, in this study, we aim to investigate the clinical significance of the IgG index in predicting Chinese patients with MS through systemically comparing it with CSF-OCB, used for differentiating the common CNS-demyelinating conditions based on age stratification, and hope to provide a clue for the preliminary diagnostic aid in the neuroimmunology clinic.Patients’ data were retrospectively reviewed from the electronic medical record system in the department of neurology in Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, between December 2019 and October 2021. Only participants who fulfilled the following criteria were included: diagnosis of relapsing–remitting MS (RRMS) according to the 2017 revisions of the McDonald criteria  and aquaAll recruited patients received the tests for IgG index within one month of the clinical attack, some of whom additionally received the CSF-OCB detection performed by IEF (SEBIA HYDRASYS), with both CSF and blood samples in the two testings obtained at the same time. The IgG index was detected using a rate immunonephelometry technique (SIEMENS BN-II) and calculated as the quotient of the QIgG (CSF-to-serum IgG ratio) and Qalb . Detection of CSF-OCBs was defined as positive if patterns 2 or 3 were present ,16.k) was used to assess the agreement of the IgG index and CSF-OCB with the diagnosis. A k < 0 refers to poor agreement, 0.01–0.2 slight, 0.21–0.4 fair, 0.41–0.6 moderate, 0.61–0.8 substantial, and 0.81–1.0 approximately perfect agreement. The optimal cutoff value or threshold associated with the outcome (diagnosis) was determined by receiver operating characteristic (ROC) curve analysis. The significance of the stratified variable in the crosstab was assessed by Cochran and Mantel–Haenszel (CMH) tests. All data were analyzed using IBM SPSS 23 software, with a 2-sided p < 0.05 considered significant.Mann–Whitney test was used for continuous distributions to compare between groups, with Fisher’s exact test for nominal data. Bivariate and partial correlations, as well as their significance, were performed by Spearman’s rank correlation analyses. Cohen’s kappa (p = 0.22), while the patients with RRMS had a significantly lower onset age and age at LP than those with AQP4-Ab NMOSD (both p < 0.001). Additionally, the IgG index and the number of positive CSF-OCB in the RRMS group were markedly higher than those in the NMOSD counterpart (both p < 0.001), whereas a relatively elevated Qalb was observed in the latter group (p = 0.005). Notably, neither of the complement components C3 nor C4 in the serum was statistically different between groups (both p > 0.1).A total of 171 patients (81 with RRMS and 90 with AQP4-Ab NMOSD) were recruited, and their clinical laboratory profiles are summarized in To clearly demonstrate the correlations between variables, Spearman’s correlation analysis was used and showed that the diagnosis was significantly associated with the age at onset, with the correlation coefficient of 0.54, followed by the age at LP (0.516), the number of positive CSF-OCB (−0.418), and the IgG index (−0.411). This suggested that age, especially at the onset, could serve as the preliminary classifier between RRMS and AQP4-Ab NMOSD.p < 0.001). Then, in the early onset age (onset age ≤ 38.5 y) group, the optimal threshold of the IgG index for prediction was 0.67 ; while in its late-onset age (onset age >38.5 y) counterpart, this figure was 0.8 , i.e., an elevated IgG index was defined as a value > 0.67 when the onset age was ≤38.5 y or that ≥0.8 when the age was >38.5 y.A preliminary classification was built based on the onset age performed by ROC curve analysis, which revealed that 38.5 years could serve as the optimal cutoff value in differentiating between the two diseases, with the sensitivity of 0.741 and specificity of 0.8 , whereas it could achieve moderate agreement with the final diagnosis in the late-onset age group , with significant CMH tests (both p < 0.01). By comparison, the IgG index could predict the diagnosis in both early and late-onset age groups with a fair-to-moderate agreement (both k ≥ 0.4 and p < 0.001), and the CMH tests were also significant (both p < 0.001). Notably, when patients with different onset ages were pooled, both IgG index and CSF-OCB could well classify the two conditions (both p < 0.001), with a relatively higher agreement observed when the IgG index served as the classifier (IgG index vs. CSF-OCB: 0.56 vs. 0.4).Crosstabs based on the stratification of the onset age were built to compare the differences between IgG index and CSF-OCB in the diagnostic prediction . In the In the early onset age group, although CSF-OCB had a slightly higher positive predictive value (PPV) than IgG index (0.935 vs. 0.887), the latter outperformed the former in sensitivity, specificity, negative predictive value (NPV), and predictive accuracy (PA). However, with the increase in age at onset (>38.5 y), in the scheme in which CSF-OCB served as the discriminator, the sensitivity and PPV decreased, while the specificity, NPV, and PA were elevated, with similar trends also observed in the scheme in which IgG index was employed as a distinguisher. Meanwhile, the IgG index algorithm had a markedly high NPV (0.921) yet a lower PPV (0.533) than its CSF-OCB counterpart. Nonetheless, in the pooled group, concerning all the assessments except PPV, the IgG index had an improved level of performance, compared with CSF-OCB, in differentiating between the two diseases.k < 0.3, p > 0.1), while the IgG index still could   and substantial  agreement with each other, respectively.Notably, if the patients with RRMS who had only one clinical attack were excluded, the optimal cutoff value of the onset age remained 38.5 y, but the CSF-OCB failed to predict the diseases in either early or late-onset age group (both  < 0.01) . MoreoveInterestingly, if the age at LP served as the preliminary classifier, with the optimal threshold of 44.5 y, almost the same results as those achieved by the onset age were observed . HoweverAccording to these results above, a simple discriminative practice scheme based on the onset age and IgG index was constructed , with boAs the blood–CSF barrier permeability may vary between males and females, we further investigated this difference and found that female sex was correlated with a lower Qalb and total protein, as well as albumin level, in CSF of both MS and NMOSD groups . Howeverk = 0.4, p < 0.001) with the diagnosis, while the CSF-OCB failed . However, when the patient was older than 38.5 y at onset, both IgG index with the cutoff value of 0.8 and CSF-OCB could predict the final diagnosis with moderate consistency . These results suggest that it may not be appropriate to classify Chinese patients with early onset ages by the presence of CSF-OCB, whereas the predictive values of the IgG index and CSF-OCB were similar in those with late-onset ages. On the other hand, these also imply that the IgG index still has a role in discriminating between RRMS and NMOSD. In centers where AQP4 antibody (by CBA) and CSF-OCB (by IEF) assays are not available or in cases where these tests are not affordable for candidate patients with RRMS or NMOSD, our practical scheme could be applied as a preliminary diagnostic aid or may provide diagnostic clues as to which patients should be detected especially for antibodies.In this study, we compared the IgG index and CSF-OCB for distinguishing RRMS from AQP4-Ab NMOSD and revealed that the IgG index could better discriminate between the two diseases based on the stratification of the onset age and different cutoff values. When the age at onset was no more than 38.5 y, the IgG index with the threshold of 0.67 could achieve fair agreement (p = 0.062) in patients with NMOSD, while this association was statistically absent in those with RRMS  (p < 0.001), implying an age-dependent, attenuated blood–CSF barrier function. This dysfunction may subsequently facilitate the passive transfer of the albumin and immunoglobulin as well as the migration of immune cells, including the antibody-secreting cells (ASCs), from the periphery to the CNS and lay a foundation for the intrathecal immunoglobulin synthesis, which may partially account for the elevated IgG index with the increased age in patients with NMOSD, leading to a rise in the optimal cutoff value of IgG index (0.8) between NMOSD and RRMS when the candidates aged more than 38.5 y. In this context, the schemes that simply employed the presence of intrathecal IgG synthesis as the distinguisher would lead to the low specificity. By contrast, our optimized algorithms maximized the discrimination by defining different thresholds of the IgG index based on the stratification of the onset age, regardless of the presence of intrathecally synthesized IgG, and demonstrated a potentially improved discriminative ability  , suggest ability . However ability . In factp < 0.05, k < 0.3, p > 0.1) while the IgG index still could   , outperfp = 0.864) or the age at LP (p = 0.983) was controlled in the partial correlation analysis (Interestingly, although patients with NMOSD had a significantly higher Qalb value than those with RRMS , Qalb dianalysis , suggestp < 0.001, Both the onset age and age at LP herein were significantly correlated with the diagnosis (The sex-related differences in blood–CSF barrier permeability were previously observed in a CSF analysis between hospital and general populations , betweenAlthough the vasculocentric deposition of immunoglobulin and activated complement components was observed in the NMOSD lesions ,30,31, wOur study was limited by the relatively small number of the patients, especially those with NMOSD who received CSF-OCB testing, which is possibly attributed to the selection bias in clinical practice and may lead to a potentially incorrect estimate of the diagnostic value of this testing method. In addition, admittedly, dichotomizing a continuous variable is not the optimal solution statistically  but has In summary, the IgG index may still have a role in discriminating between RRMS and AQP4-Ab NMOSD, as CSF-OCB in China is not as sensitive as that in western countries. Different thresholds defined based on the stratification of the onset age or age at LP can improve the predictive value of the IgG index and help achieve, at least, the non-inferior, or even superior, accuracy and sensitivity to the CSF-OCB herein. Accordingly, this optimized scheme may be applied as an alternative in cases where CSF-OCB testing by IEF is unavailable or affordable. Notably, although the diagnosis of MS has been facilitated by the advancement of MRI imaging, it remains a great challenge to differentiate it from the MS mimics, especially in those with only spinal or optic nerve injuries or one clinical attack, due to lack of a specific antibody similar to AQP4-Ab in NMOSD. Comprehensively collecting and assessing the data from a candidate patient is required before a probable diagnosis is drawn. Occasionally, time will tell.


Cerebrospinal fluid (CSF) is produced by the choroid plexuses within the ventricles of the brain and circulates through the subarachnoid space of the skull and spinal column to provide buoyancy to and maintain fluid homeostasis of the brain and spinal cord. The question of how CSF drains from the subarachnoid space has long puzzled scientists and clinicians. For many decades, it was believed that arachnoid villi or granulations, outcroppings of arachnoid tissue that project into the dural venous sinuses, served as the major outflow route. However, this concept has been increasingly challenged in recent years, as physiological and imaging evidence from several species has accumulated showing that tracers injected into the CSF can instead be found within lymphatic vessels draining from the cranium and spine. With the recent high-profile rediscovery of meningeal lymphatic vessels located in the dura mater, another debate has emerged regarding the exact anatomical pathway(s) for CSF to reach the lymphatic system, with one side favoring direct efflux to the dural lymphatic vessels within the skull and spinal column and another side advocating for pathways along exiting cranial and spinal nerves. In this review, a summary of the historical and contemporary evidence for the different outflow pathways will be presented, allowing the reader to gain further perspective on the recent advances in the field. An improved understanding of this fundamental physiological process may lead to novel therapeutic approaches for a wide range of neurological conditions, including hydrocephalus, neurodegeneration and multiple sclerosis. Being arguably the most sophisticated organ, the brain requires ample protection from mechanical and molecular harm. The skull provides defense against physical insults, while the blood–brain barrier prevents foreign and potentially dangerous molecules from entering the brain. The cerebrospinal fluid (CSF) contained within the ventricles and subarachnoid space (SAS) provides another layer of support by creating a chemically and mechanically stable environment that is tightly controlled by additional blood–CSF barriers at the choroid plexus and arachnoid mater. Homeostasis in the production, circulation, and absorption of the CSF is therefore critical for normal brain function. Several diseases may arise from disturbances in the CSF system of which the most apparent are the ‘mechanical’ CSF disorders, e.g., the different forms of hydrocephalus and idiopathic intracranial hypertension. The presumed function of the CSF as a ‘waste-sink’ for toxic metabolites of the brain and of the SAS as a site of immune surveillance further suggests great importance of CSF homeostasis in relation to the development of neurodegenerative and neuroinflammatory diseases .Many fundamental questions related to the production, circulation, and absorption of CSF remain unanswered. The studies considered to be the foundation of this field of research were first conducted around 150 years ago and since then, many different investigators have debated these topics and a satisfactory consensus has been difficult to reach –5. MajorA widely cited value for CSF volume in humans is 140 mL and it is suggested that at least 500 mL of fluid is produced and cleared from the CNS every day –8. RegarOne very active area of debate relates to the clearance pathways of cerebrospinal fluid. In most organs of the body, lymphatic vessels are present within interstitial tissue and are responsible for draining fluid and proteins that have extravasated from the blood circulation , 20. EveThe specific pathways through which the CSF can reach the lymphatic system are currently an area of great controversy. The bulk of the literature supports pathways through the cribriform plate and along cranial and spinal nerves to reach lymphatic vessels outside the CNS. However, in the last few years researchers have rediscovered a network of lymphatic vessels in the outermost meningeal layer, the dura mater, and have suggested that this could represent a more direct outflow route for CSF. This exciting finding has raised immediate questions regarding the potential mechanisms for this process, including how a barrier layer at the arachnoid mater that exists between the SAS and the dura mater could be traversed.This review will first closely examine the historical and contemporary evidence for the three major proposed anatomical pathways for clearance of CSF from the cranium: arachnoid projections (villi or granulations), routes through foramina in the skull along cranial nerves (including the cribriform plate) and lymphatic vessels of the dura mater. Next, a description of the studies on CSF outflow from the spine will be presented. Subsequently, a detailed account of the physiological in vivo studies utilizing quantification of tracers and/or in vivo imaging will be provided. Finally, a summary of the limited evidence from humans and a discussion of the major open questions will attempt to set the stage for future work on this topic.The textbook model of CSF circulation states that arachnoid projections within the skull are the main CSF outflow site. Arachnoid projections are outcroppings of arachnoid tissue that extend through the dura into the major venous sinuses and the associated lacunae laterales and were first described in 1705 by the Italian anatomist Antonio Pacchioni . There aA potential function for these structures remained elusive until the classic experiments of Key and Retzius published in 1875 . In humaOne early point of controversy was that arachnoid granulations could not be found in lower vertebrates or in human infants . Therefo2O) of isotonic solutions of equal parts iron ammonium citrate and potassium ferrocyanide were then introduced into the spinal SAS at a slow rate. After various times of this infusion, the animals were killed. Weed then perfused the animals, via intracarotid injection, with a solution of formalin containing 1% hydrochloric acid. In this manner, the formalin fixed the brain and meninges, and the acid precipitated to form granules of Prussian blue from the previously introduced salts. Through this method, he avoided introducing particulate matter into the SAS which could have obstructed potential outflow pathways. In some animals, instead of perfusion, he severed the head intact and incubated the tissue for days in a solution of formaldehyde and hydrochloric acid. Weed found that after short periods of infusion, the Prussian blue granules were mainly located in the basal cisterns and the cavernous sinus, and, after longer periods of several hours, they were found concentrated above the cerebral hemispheres. At this location, he described microscopic structures of fine, web-like interlacing cords, which he termed arachnoid villi, that invaginated the arachnoid membrane into the dural superior sagittal sinus . This pathway is described as an extension of the meningeal layers such that the SAS is continuous with the perineural space along the nerves as they exit through foramina within the cribriform plate , 137. ThThe first model suggests that the perineural cells are loosely adhered to the olfactory axon which allows fluid and solutes to easily access the interstitial spaces of the submucosa . In thisIn the second model the perineurium would exhibit barrier properties similar to the meninges within the skull . This moTracer studies have provided support for both of these models. Lewis Weed’s studies with Prussian blue precipitate indicated that the connections were not direct, as tissue spaces always intervened between the perineural spaces and lymphatics. Several other studies performed in rabbits are in agreement , 92, 108A third emerging model is based on evidence from rodents showing that lymphatic vessels appear to cross through the cribriform plate which may allow them to access the SAS directly , 143–145Some older studies utilizing injections post mortem have suggested pathways through the plate not associated with perineural spaces or lymphatic vessels , 94. LatThus, there is very strong evidence for an efflux route for CSF through the cribriform plate in many different species, although the detailed anatomical connections from the SAS to lymphatic vessels still need elucidation.retractor bulbi muscle” . . 118]. SFluorescence imaging techniques in rodents have recently been employed to visualize tracer outflow to lymphatic vessels. Mathieu et al. utilized a whole animal hyperspectral fluorescence imaging system to detect quantum dot efflux to the superficial cervical lymph nodes of mice . RecentlMagnetic resonance imaging techniques hold great promise to evaluate the pathways of CSF flow in a dynamic, three-dimensional fashion with simultaneous anatomical visualization. Several investigators have explored the outflow of CSF using MRI techniques in animal studies. In an early study, Di Chiro et al. injected Gadolinium-DTPA into the cisterna magna of normal dogs and were able to visualize the efflux of the contrast agent across the cribriform plate into the nasal submucosa , replicaMore recent studies have utilized T1-weighted MRI and gadolinium-labeled contrast agents to map CSF flow pathways and efflux routes in rodents. Although not focused on determining the CSF efflux sites, a study by Gakuba et al. in isoflurane-anesthetized mice clearly shows enhancement of Gd-DOTA in what appears to be a continuous pathway through the cribriform plate, to the nasal (sub)mucosa and nasopharyngeal region to the deep cervical lymph nodes within 5 min of cisterna magna injection . A studyIt is to be expected that tracer injections, particularly when performed in a bolus fashion at high volumes and/or within short time periods, could alter the physiological flow patterns of CSF. This appears to be particularly apparent when injections are made into the intrathecal space of the spine , 239 wheUnlike in animals, evidence of defined CSF outflow pathways in humans is lacking. Early studies involving tracer injections in cadavers have provided evidence for routes through arachnoid granulations  and to tOther insights on CSF outflow in humans have come from neuropathological assessments. Since arachnoid villi have long been considered the major efflux site, the morphology of these structures has been examined post mortem in cadavers of patients that have died from clinical conditions, such as intracranial hemorrhage or meningitis. In one of the first studies of this nature, post mortem evaluation of arachnoid granulations demonstrated infiltration of inflammatory cells in meningitis and red blood cells after hemorrhage . The autIn a provocative new study from a Spanish group, the authors utilized nasal swabs in an attempt to identify biomarkers in patients that had suffered from stroke. The authors were able to differentiate patients that had suffered from hemorrhagic stroke compared with ischemic stroke by the amount of iron in the nasal exudate. Although this study was preliminary, consisting of samples from only 20 patients, it serves as in vivo clinical evidence that CSF waste products may be cleared through nasal pathways, at least during pathological conditions .Since the rediscovery of dural lymphatic vessels there has been a renewed push to image potential CSF outflow pathways in humans. These studies thus far have not been conclusive. Absinta et al. found that dural lymphatics could be visualized with MRI alongside the SSS in humans and primates . These a99mTc-DTPA tracer [De Leon et al. performed intravenous injection of two different low molecular weight radiotracers known to cross the CNS barriers and were able to highlight a potential efflux of CSF through the cribriform plate. Dynamic imaging with PET was superimposed on MRI images from each patient and showed clear enhancement of the superior nasal turbinates . Eide etA tracer . The autThe existing evidence from animal and human studies for the various CSF outflow pathways is summarized in Fig. There has been intense focus on dural lymphatic vessels since their rediscovery in 2015 , 255–260As is clear from this review, there is overwhelming historical evidence for perineural outflow pathways for CSF that have barely been acknowledged in several recent publications , 262. Of


Transplantation of allogeneic hematopoietic cells faces two barriers: failure of engraftment due to a host versus graft reaction, and the attack of donor cells against the patient, the graft versus host (GVH) reaction. This reaction may lead to GVH disease (GVHD), but in patients transplanted due to leukemia or other malignant disorders, this may also convey the benefit of a graft versus leukemia (GVL) effect. The interplay of transplant conditioning with donor and host cells and the environment in the patient is complex. The microbiome, particularly in the intestinal tract, profoundly affects these interactions, directly and via soluble mediators, which also reach other host organs. The microenvironment is further altered by the modifying effect of malignant cells on marrow niches, favoring the propagation of the malignant cells. The development of stable mixed donor/host chimerism has the potential of GVHD prevention without necessarily increasing the risk of relapse. There has been remarkable progress with novel conditioning regimens and selective T-cell manipulation aimed at securing engraftment while preventing GVHD without ablating the GVL effect. Interventions to alter the microenvironment and change the composition of the microbiome and its metabolic products may modify graft/host interactions, thereby further reducing GVHD, while enhancing the GVL effect. The result should be improved transplant outcome. The Iliad)“… he first commanded Bellerophon to kill that savage monster, the Chimaera, who was not a human being, but a goddess, …”  at the time of transplantation, the transplant conditioning regimen, the source of donor cells, HLA mismatch between donor and patient, and the development of (chronic) GVHD. MRD, in particular, is currently an area of extensive research. The level of detection of MRD depends upon the methodology used  –14. WhilEarly data on global T-cell depletion of the donor cell inoculum before infusion into the patient showed substantial reduction of the incidence of GVHD but also resulted in a high rate of graft failure and disease relapse . More reOne strategy is the administration of post-transplant cyclophosphamide (CY), originally for HLA haplo-identical transplants but then extended to other donor/host combinations . The redin vitro depleted of CD45RA+ T cells achieved sustained engraftment, had a very low incidence of severe acute and chronic GVHD, and were not at a higher risk of relapse than patients transplanted with T cell-replete grafts , antation ? Severalantation –35. In oantation . These pantation . Howeverhe tumor . Ongoinghe tumor .GVL effect, these patients also experienced a recipient vs. leukemia effect, suggesting activation of the patient's immune system by the infused HLA non-identical donor cells -mobilized peripheral blood progenitor cells  at various doses, from HLA-mismatched donors in patients with AML in first remission who were not given any GVHD prophylaxis . Donor cor cells . The samnovo AML , but conin vitro data from patients with MDS, which show a two-way signaling path between the clonal disease cells and non-clonal mesenchymal/stroma cells . Several reports have postulated a “leukemogenic effect” of the marrow microenvironment , 47. Is Blautia, appear to have a beneficial effect, others, for example, Veillonella or enterococcal species such as Enterococcus faecium or Enterococcus faecalis, favor the development or propagation of GVHD, leading to inferior transplant survival  occurred without clinical evidence of GVHD, suggesting the possibility that the presence of mixed chimerism, albeit temporary, facilitated the establishment of tolerance.Viral organisms such as picobirna viruses have also been shown to participate in these donor/host interactions , and theHomo sapiens trying to break down barriers that have evolved over millions of years. Doing so upsets the balance that we observe in healthy individuals. Of course, these therapeutic interventions are directed at the eradication of a malignant disease, which has already changed the internal milieu. A better understanding of signals that trigger the development of malignant disorders such as leukemia would allow for earlier interventions and might permit their exploitation to restrict the reactions of donor cells to the GVL effect, while preventing GVHD. Can we direct the divine ability of the chimera against the malignancy and sever the ugly head of GVHD? Current research using state of the art tools, including systems biology and machine learning, may be able to pave the way.The interactions between donor and recipient cells following allogeneic HCT are complex, and the cast of characters of this drama is not limited to donor and recipient immune cells. Additional actors include cellular and non-cellular components of the microenvironment and, importantly, the microbiome. Nature had not envisioned The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.The author confirms being the sole contributor of this work and has approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Midazolam is frequently used for sedation during spinal anesthesia. However, external environmental factors, such as bright surgical lights, may hamper patient relaxation, which may lead to an increase in the dose of midazolam required and the likelihood of adverse drug effects. We investigated whether using an eye mask to block the external environment could reduce midazolam requirements during spinal anesthesia.n = 20) and a control group . The sedation level was assessed using a modified Observer Assessment of Alertness and Sedation (MOAA/S) scale. Midazolam (1 mg) was incrementally administered every 5 min until moderate sedation (MOAA/S score of 3) was achieved. The bispectral index (BIS) was monitored, and the onset and maintenance times of a BIS < 80 were recorded.Participants aged 18–‒80 years, scheduled for elective surgery under spinal anesthesia, were randomly divided into a masked group . However, the onset and maintenance times for a BIS < 80 were similar. In addition, there were no significant differences in the incidence of side effects or patient satisfaction between the two groups.The two groups had similar demographic characteristics. The midazolam requirements were significantly lower in the masked group than in the control group  entitled “Can we reduce an amount of sleeping pills just by blocking light?”. During regional anesthesia, intravenous sedatives are commonly administered to patients for various reasons. The sedatives relieve the patient’s anxiety and induce hypnosis, making the patient more comfortable during surgery . HoweverAmong various sedatives, midazolam has long been used during spinal anesthesia because of its advantages of a faster onset of action, short duration of hypnosis, and ease of use , 3. MidaWe hypothesized that if conditions that interfere with patient sedation in the operating room could be blocked, the appropriate level of sedation could be achieved more easily and safely, without excessive administration of hypnotics. There have been many studies on the dose and side effects, as well as comparisons and combinations of sedatives, but few studies have investigated how to reduce the dose of sedatives and still achieve the desired level of sedation. Therefore, we aimed to investigate the auxiliary sedation effect of using an eye mask to block strong light in patients undergoing surgery. Specifically, we sought to determine whether and to what extent the use of an eye mask by the patient could reduce the amount of midazolam required to achieve sufficient sedation in patients undergoing surgery during spinal anesthesia.This prospective, randomized, controlled trial was approved by the relevant hospital ethics committee  and retrospectively registered with the Clinical Research Information Service (CRIS) . The study included 40 adult patients aged 18–80 years who were scheduled for elective surgery under spinal anesthesia at a tertiary care hospital between August 2017 and August 2018. The exclusion criteria were as follows: American Society of Anesthesiologists physical status (ASA PS) ≥ 3, pregnancy, sleep disorders such as sleep apnea, intellectual disability, or any contraindication to spinal anesthesia. Patients who refused to take sedatives or wear an eye mask were also excluded. In the afternoon on the day before surgery, one of the researchers visited the ward of the study subject, judged their eligibility, and went through an explanation and consent procedure. All patients read the consent form by themselves and were able to consent in writing based on their voluntary judgment. After obtaining informed consent, 40 patients were enrolled and randomly assigned to two parallel groups of 20 patients each in a 1:1 ratio. The group wearing an eye mask was defined as the masked group, and the group without an eye mask was used as the control group. The study was performed in accordance with the Ethical Principles for Medical Research Involving Human Subjects, outlined in the Declaration of Helsinki of the World Medical Association.Routine premedication was not administered. All patients were evaluated with an electrocardiogram, noninvasive blood pressure monitoring system, and pulse oximeter, and a 20-gauge intravenous catheter was inserted into the patient’s forearm. We injected 10‒14 mg of 0.5% hyperbaric bupivacaine  intrathecally via a 25-gauge spinal needle for spinal anesthesia. All techniques were performed using a midline or para-median approach in the lateral decubitus position. The patient was placed in the supine position, and nasal prong with capnography and bispectral index (BIS) monitoring devices were applied. The sensory block level was evaluated using the cold skin test, and the Trendelenburg position or the reverse Trendelenburg position was used as appropriate to control the thoracic sensory block level T6–10. Twenty minutes after bupivacaine administration, the block height was re-evaluated using the cold skin test and recorded. An eye mask was then applied to the masked group.Firstly, to measure the dose of midazolam required for sedation, the main outcome of the study, intravenous midazolam (1 mg) was incrementally administered every 5 min, and the level of sedation was repeatedly evaluated using a modified Observer Assessment of Alertness and Sedation (MOAA/S) scale . We used only scores of five, four, and three out of the six possible MOAA/S scale categories. One researcher spoke the patient's name in the same normal tone to evaluate the MOAA/S score every 5 min after midazolam administration. If the patient responded readily and normally, a MOAA/S score of 5 was assigned; if the response was lethargic, a MOAA/S score of 4 was assigned, and if the patient did not respond, a MOAA/S score of 3 was given. There was no additional stimulation such as loud or repetitive naming, mild prodding or shaking, or painful squeezing; therefore, MOAA/S scores < 3 were not identified. We defined a MOAA/S score of 3 as “sufficient sedation” and MOAA/S scores of 4 or 5 as “insufficient sedation,” and if the patient was in an “insufficient sedation” state, an additional 1 mg of midazolam was administered until “sufficient sedation” was achieved. This was repeated every 5 min for a maximum of 35 min, and the time to reach an MOAA/S score of 3 and the dose of administered midazolam were recorded. If “sufficient sedation” was not reached by 35 min (7 mg of midazolam), the outcome was defined as “sedation failure,” and the time was recorded as 40 min. For consistency, all evaluations were performed by a single researcher (Dr. S. W. Yoo).We also evaluated the BIS at the same time points as the MOAA/S scores were assessed. Firstly, to evaluate the onset of sedation more objectively, the time to reach a BIS < 80 was measured. Secondly, the duration of sedation was evaluated by measuring the length of time from the onset of a BIS < 80 until the BIS returned to a level > 80. Maintenance time was excluded if the operation was completed before spontaneous awakening of the patient. In addition, vital signs were recorded from the time of midazolam administration until the end of surgery. Twenty minutes after bupivacaine administration (at 0 min of midazolam administration) was defined as baseline. Systolic blood pressure and heart rate decreases by > 20% from this baseline were regarded as the development of hypotension and bradycardia, respectively. Transient hypotension induced by tourniquet release was also excluded. Apnea was defined as the repeated interruption of airflow for > 10 s based on capnography. After surgery, all patients were transferred to the recovery room, and approximately 30 min later, one of the researchers assessed patient satisfaction with sedation .t-test sample size calculation, with an average of 1 mg and a standard deviation of 1 mg based on a previous study [t-test or Mann–Whitney U test was used depending on whether or not the data were normally distributed for continuous variables, and the χ2 test or Fisher’s exact test was used for categorical variables. The cut-off for statistical significance was set at P < 0.05.When the difference in midazolam dose between the two groups was estimated using G Power 3.1.9.7 software’s independent us study , we deteOf the 40 patients enrolled, two were excluded for refusing spinal anesthesia on the day of surgery. Consequently, 38 patients were included in the analysis Fig. . There wP = 0.024) (Table P = 0.024). Figure P = 0.264). Similarly, the duration of time in which the BIS was maintained at < 80 corresponded to 28.6 min in the masked group and 21.4 min in the control group, with no significant differences between groups (P = 0.183).In the masked group and the control group, the midazolam doses required to reach an MOAA/S score of 3 were 2.8 mg and 3.7 mg, respectively. The masked group required a significantly lower midazolam dose than the control group , nor was there any significant difference in the incidence of apnea between groups (P = 0.395). Furthermore, there was no significant difference in patient satisfaction with sedation between the masked and control groups (P = 0.588). None of the patients experienced sedation failure.There was no significant difference in the incidence of relative hypotension or bradycardia between the masked group and the control group  could reduce the amount of midazolam required for adequate sedation in patients undergoing surgery under spinal anesthesia. The results of this study show that the masked group required a significantly lower dose of midazolam to reach an MOAA/S score of 3 compared to the control group. When 1 mg of midazolam was administered every 5 min, the doses of midazolam required to reach a MOAA/S score of 3 were 2.8 mg and 3.7 mg in the masked group and the control group, respectively, a difference of about 0.9 mg. We found that the midazolam dose could be reduced by controlling the amount of bright light in the environment. Although there were no significant differences between groups based on BIS measurements, a faster onset and a longer duration of sedation were observed in the masked group than in the control group. This suggests the need for further studies with larger sample sizes.Although midazolam is the most frequently used sedative for minor surgeries or procedures, it is difficult to titrate the ideal dose because of large individual variability in responses . AccordiIn terms of the onset time to reach a BIS ≤ 80, the masked group and the control group required 12.3 min and 14.7 min, respectively, which was faster than the times required to reach an MOAA/S score of 3 of 13.8 min and 18.3 min, respectively. This is probably because a BIS of 80 does not reflect an MOAA/S score of 3. According to the manufacturer’s report, a BIS of 80 corresponds to “Light/moderate sedation, may respond to loud commands or mild prodding/shaking,” which is similar to the MOAA/S score of 3 [Intrathecal local anesthetic appears to stop spreading 15‒25 min after injection , 19, 20.This study had several limitations. Above all, our study was not a blinded trial, as the researcher was inevitably able to distinguish whether the patient was wearing an eye mask or not. Therefore, it was not possible to completely prevent the risk of bias, especially detection bias. In addition, the type of surgery differed across patients, and variables such as noise were not controlled for. We only classified the MOAA/S scores of 5, 4, and 3, but not those < 3, for the following reasons: first, we did not want to harm the patient with unnecessarily deep sedation beyond the light/moderate sedation required. Second, other stimuli, such as speaking loudly, prodding, or shaking, to classify MOAA/S scores < 3, may have affected the results by interfering with the patient’s sedation. Third, there was a limitation in evaluating the response of the patient’s eye opening in the masked group, and thus the judgment of the MOAA/S score could have differed between the two groups.An eye mask is an easily used, noninvasive, and cost-free method for reducing external anxiety-causing stimuli. Our findings suggest that blocking light using an eye mask during spinal anesthesia can reduce the requirement for sedatives such as midazolam. In the future, additional studies will be necessary to verify the reproducibility of the present findings and to examine the relationships between various drugs and environmental factors.


Cerebrospinal fluid (CSF) circulation between the brain and spinal canal, as part of the glymphatic system, provides homeostatic support to brain functions and waste clearance. Recently, it has been observed that CSF flow is strongly driven by cardiovascular brain pulsation, and affected by body orientation. The advancement of MRI has allowed for non-invasive examination of the CSF hydrodynamic properties. However, very few studies have addressed their relationship with body position . It is important to understand how CSF hydrodynamics are altered by body position change in a single cardiac phase and how cumulative long hours staying in either upright or supine position can affect craniocervical CSF flow.In this study, we investigate the changes in CSF flow at the craniocervical region with flow-sensitive MRI when subjects are moved from upright to supine position. 30 healthy volunteers were imaged in upright and supine positions using an upright MRI. The cranio-caudal and caudo-cranial CSF flow, velocity and stroke volume were measured at the C2 spinal level over one cardiac cycle using phase contrast MRI. Statistical analysis was performed to identify differences in CSF flow properties between the two positions.CSF stroke volume per cardiac cycle, representing CSF volume oscillating in and out of the cranium, was ~ 57.6% greater in supine (p < 0.0001), due to a ~ 83.8% increase in caudo-cranial CSF peak velocity during diastole (p < 0.0001) and extended systolic phase duration when moving from upright (0.25 ± 0.05 s) to supine . Extrapolation to a 24 h timeframe showed significantly larger total CSF volume exchanged at C2 with 10 h spent supine versus only 5 h (p < 0.0001).In summary, body position has significant effects on CSF flow in and out of the cranium, with more CSF oscillating in supine compared to upright position. Such difference was driven by an increased caudo-cranial diastolic CSF velocity and an increased systolic phase duration when moving from upright to supine position. Extrapolation to a 24 h timeframe suggests that more time spent in supine position increases total amount of CSF exchange, which may play a beneficial role in waste clearance in the brain. Cerebrospinal fluid (CSF) plays an important role in providing structural and homeostatic support  to the cTo further support such close connection, CSF movement has been shown to be strongly driven by arterial pulsation , 6, whosThe advancement of MRI has furthered traditional studies of CSF flow evaluation, allowing non-invasive examination of pulsatile hydrodynamic properties. However, very few studies have addressed the changes in CSF hydrodynamics that might follow a shift in body position. It is well established that moving from an upright to a supine position can cause the decrease of the heart rate (HR) –12. SuchIn this light, it is important to understand how postural changes alter CSF hydrodynamics; especially since the underlying biophysiological mechanisms are still poorly understood. Studies have reported that CSF flow along the perivascular space and via the glymphatic pathway may play a crucial role in maintaining brain functions and waste clearance in aging and age-related dementia, as extensively reviewed by Simon and Iliff  and receHence, the purpose of this study was to investigate changes in CSF flow and volume exchange at the C2 cervical spinal subarachnoid space when the body position of healthy subjects is changed from upright to supine using flow-sensitive MRI.MRI scans from 30 asymptomatic volunteers  were studied retrospectively. Scans were obtained from the research and development database of the MRI device manufacturer  between April 8, 2014 and May 2, 2016. Volunteers in this database were scanned for the purpose of internal research and CSF flow reference. Originally, 65 subjects were enrolled and scanned. Scans were subsequently excluded from the study based on the following exclusion criteria: (1) evidence of neurologic symptoms and evident spinal abnormalities , identified on T2 and T1-weighted MRI images, (2) Poor image quality, as screened by three independent readers, for imaging slice placement as well as artifacts such as velocity aliasing and movement (N = 19). If either supine or upright images did not pass the screening, the corresponding subject’s data was entirely excluded from further analysis. Written informed consent was obtained at the time of the appointment. This retrospective study, and the scan data, was both initially recorded and reviewed in a de-identified manner with no personal health identifiers attached to it. Therefore this study is IRB exempt.All the MRI scans were performed on a 0.6T MRI, which allows images to be obtained with the subject in both upright and supine body positions. A quadrature craniocervical junction coil was used to image the foramen magnum and upper cervical spine region. As shown in Fig. Throughout the scanning session, cardiac blood flow waveform was measured with a photo plethysmograph  placed on the subject’s finger. This was then used to register each cardiac cycle and to reconstruct the MRI data into 32 images over the cardiac cycle; a technique commonly referred to as retrospective MRI gating.After the images were acquired, quantification of CSF flow and spinal cord pulsation was accomplished by manually drawing regions of interest (ROI) in the spinal canal around the spinal cord on the axial mid-C2 PC-MRI scan Fig. C, D. TheThe volume flow through the CSF canal was derived by multiplying the CSF velocity with the area of pericord CSF canal. Figure From the velocity and flow rate time curves, various parameters can be extracted Tables  and 2. CA two-tailed paired Student’s t-test was used to determine statistically significant differences in CSF hydrodynamic parameters between the upright and supine positions. Percentage change between upright and supine measurements for each subject was calculated using the following equation: ((supine-upright)/upright)*100.Change in position from upright to supine resulted in a significant decrease in heart rate (HR) (p < 0.0001). HR was ~ 9.5% slower in the supine position Fig. A. To furThe individual contributions of systole and diastole to the cardiac cycle and their relationship to the heartbeat were further analyzed. To allow comparison between the different body positions, the data was normalized by looking at how much of a single cycle each phase covers . In the upright position, systole made up about 30.9 ± 4.5% of the cycle on average, and diastole the remaining 69.1 ± 4.5%. In the supine position, there was a ~ 22.6% increase in systolic fractional duration compared to upright, bringing it to 37.7 ± 6.4% of the cycle in supine, which can potentially lead to the increased stroke volume. This was compensated by a ~ 10.1% decrease, from what measured in upright, of diastolic fractional duration, which then made up circa 62.3 ± 6.4% of the cycle in supine. Such changes were all statistically significant (p < 0.0001) and are represented in Fig. 3/cycle) and diastolic (− 0.57 ± 0.19cm3/cycle) CSF volume displaced at C2 spinal level was higher in magnitude compared to what was measured in the upright position   and systole . CSF peak velocity during diastole, in the caudo-cranial direction, significantly increased from − 0.37 ± 0.13 cm/s in upright to − 0.68 ± 0.24 cm/s in the supine position (p < 0.0001). However, no significant changes in CSF peak systolic velocity were observed between supine (1.16 ± 0.35 cm/s) and upright  positions  during diastole and positive values  in systole, as plotted in Fig. 01) Fig. A. To inv3/min) compared to upright (24.75 ± 7.93 cm3/min). A per hour rate was then extrapolated and showed similar significant patterns of change, with a ~ 42.7% increase of CSF exchanged in supine (2118.67 ± 700.35 cm3/hour) compared to what measured in upright position (1484.97 ± 475.58 cm3/hour)  contributes to a 25.2% decrease of CSF exchanged, whilst the extra 5 h spent upright only increase the CSF exchange by 17.7% of the total stroke volume.Stroke volume, defined as CSF volume exchanged between the spinal and intracranial space over a single cardiac cycle, was ~ 57.6% greater in supine compared to upright  to supine (bottom row), can be seen in Fig. Three subjects were recruited and scanned three times in the upright position and then three times in the supine position, to evaluate the test–retest reproducibility. Exact same PC-MRI parameters and settings described in the methods section were used. Since the analysis was focused on within subject reproducibility, we found low coefficient of variation (CV < 10%) for CSF stroke volume measurement in all three subjects, which proves that the changes due to body position observed are significantly greater than the test–retest variation.Circulation of CSF between ventricle, interstitial, and subarachnoid space, as well as between brain and spinal canal serves multiple important functions to support CNS including waste clearance through the glymphatic network. The adaptive physiologic methods used by the CNS to maintain a homeostatic balance of brain fluid movement in the setting of body position shifts have not yet been thoroughly studied, particularly with noninvasive quantitative imaging approaches such as MRI. However, few studies suggested important adaptive physiological mechanisms that the human body utilizes to maintain the CNS in constant, optimal equilibrium.One of such mechanisms, thoroughly well-addressed in current literature, is the change in HR when moving from upright to supine positions or vice versa. In this study, we showed that subjects in the supine position exhibit a significantly slower HR compared to upright. This is in line with the current literature highlighting the importance of such conservation mechanism to ensure consistent blood perfusion of the body , 11. IntFurthermore, we observed that during systole, CSF is mainly drained out of the cranium  whilst in diastole CSF mainly flows into the intracranial space . This CSF directionality is in line with findings reported in the literature –23. Our We then looked at the two main contributors to the mentioned difference in CSF volume exchanged at C2 level: CSF velocity and phase durations of CSF flow. Interestingly, they change differently when moving from an upright to a supine position. In fact, we observed that in the supine position during diastole, CSF flows into the intracranial space at peak velocity that is ~ 83.8% higher than that in upright. On the other hand, during systole, CSF is drained out of the intracranial space but, instead of compensating for the larger CSF volume via increased efflux velocity, the systolic duration increases by about 36.0%. These alterations allow for larger CSF volumes to be exchanged in the supine versus upright position. Such largely increased CSF volume exchanged in the supine position may have important implication on brain waste clearance in dementia due to altered time spent in supine position in the elderly versus younger population.Integrating our findings with what is available in the current literature, we thus obtain a general picture of the biophysiological adaptive and physical (e.g. gravity and brain structures shift) mechanisms of the brain in response to body position shift. When moving from an upright to supine position, parasympathetic  activation and sympathetic withdraw cause a decrease of heart rate as a consequence of the restored venous blood flow through the internal jugular veins, increasing the blood leaving the intracranial space and the cardiac preload during diastole . Since tThis overall system of adaptation not only provides constant structural support and protection of the brain, but also might affect the efficiency of homeostatic support. As summarized in Fig. In fact, our extrapolation showed that even only one hour spent in supine position might allow for more CSF volume to be exchanged between the spinal canal and the brain compared to one hour spent upright. Translating this extrapolation to 24 h timeframe it is evident how the longer time  spent in supine in a day might support better CSF flow in and out of the brain than shorter time . This is due to the larger contribution of supine compared to upright to the overall CSF exchanged in one day. In our example, in fact, a reduction of 5 h in the supine position, from 10 h in the first scenario to 5 h in the second one, contributes with a 25.2% decrease of all CSF exchanged over the day. However, the same increase of hours in the upright position, from 14 in the first scenario to 19 in the second one, contributes only with a 17.7% increase of all CSF exchanged over the day. These differences between the two scenarios lead to a net increase of 7.5% CSF exchanged over a single day, an important daily change quantified for assessing the cumulating effect over a period of decades of aging. It must be noted, however, that this extrapolation does not account for many physiological factors that may vary during the course of 1 h, 24 h or even decades. In fact, recent studies have observed that exercise , 29, bloNonetheless, this extrapolation’s results raise interesting questions regarding the possible age-related effects of body position. The elderly population has been found to get significantly less hours of sleep over a day compared to the younger counterpart . This, tFurthermore, Studies have even suggested a link between hindered metabolic clearance through CSF or interstitial flow and pathogenesis of neurodegenerative diseases such as Alzheimer’s Disease and Multiple Sclerosis . WhetherOne limitation of this study is that blood flow from main neck feeding arteries as well as from venous blood flow were not measured; these parameters may have provided a more comprehensive analysis. In addition, the effects of breathing on CSF flow dynamics were not measured and a recent study reported that coughing and controlled breathing can affect measurements of CSF flow –38. HoweTo the best of our knowledge, the results of our MRI study on CSF hydrodynamic components in relationship with changes in body position are in line with what previously reported in the literature , 24, 45.


Chronic pelvic pain (CPP) is a highly disabling disorder in women usually associated with hypertonic dysfunction of the pelvic floor musculature (PFM). The literature on the subject is not conclusive about the diagnostic potential of surface electromyography (sEMG), which could be due to poor signal characterization. In this study, we characterized the PFM activity of three groups of 24 subjects each: CPP patients with deep dyspareunia associated with a myofascial syndrome (CPP group), healthy women over 35 and/or parous  and under 35 and nulliparous (<35&NP). sEMG signals of the right and left PFM were recorded during contractions and relaxations. The signals were characterized by their root mean square (RMS), median frequency (MDF), Dimitrov index (DI), sample entropy (SampEn), and cross-correlation (CC). The PFM activity showed a higher power (>RMS), a predominance of low-frequency components , greater complexity (>SampEn) and lower synchronization on the same side (<CC) in CPP patients, with more significant differences in the >35/P group. The same trend in differences was found between healthy women (<35&NP vs. >35/P) associated with aging and parity. These results show that sEMG can reveal alterations in PFM electrophysiology and provide clinicians with objective information for CPP diagnosis. Chronic pelvic pain (CPP) is a complex clinical condition characterized by persistent or recurrent pelvic pain for longer than six months with no proven infection or obvious pathology . One of CPP and other clinical conditions of the pelvic floor  are closely associated with dysfunction of the pelvic floor musculature (PFM) , so thatGiven its potential to characterize PFM activity, sEMG has not been exclusively devoted to the study of the PFM in dysfunctional conditions but also to different physiological circumstances. Special attention has been paid to women’s demographic and obstetric characteristics. Different studies have reported a negative correlation between women’s age and their PFM activity ,25, as wThe purpose of the present study was (1) to characterize the PFM activity of CPP patients whose main presentation is deep dyspareunia associated with a myofascial pain syndrome and that of healthy women with similar and different demographic and obstetric characteristics to a CPP patients’ database, and (2) to assess the diagnostic value of sEMG in CPP in which musculoskeletal pelvic pain is a main component. To this end, we recorded the sEMG signal from the left and right sides of the pelvic floor with adhesive electrodes and characterized the power, spectral content and complexity of the signal during PFM maximum voluntary contractions and relaxation, as well as interactions between different regions on the same PFM side. The results obtained prove that sEMG can reveal alterations in the PFM electrophysiology associated with different processes like aging, parity, or pain and provide clinicians with objective information that can help them to better evaluate CPP patients’ condition, thus allowing more efficient management of this complex syndrome.This study is included in the clinical trial “Electromyographic Study for the Help and Guidance of Botulinum neurotoxin A Administration in the Treatment of Chronic Pelvic Floor Pain (SEMG)”  conducted at the Hospital Universitari i Politècnic La Fe , a prospective, minimally invasive, non-masked and non-randomized phase III clinical trial that meets the Helsinki Declaration. Female subjects with different demographic, obstetric, and clinical characteristics were recruited: healthy women over 35 years old and/or with previous pregnancies (group >35/P), under 35 years old with no previous pregnancies (group <35&NP), and women with CPP for more than 6 months whose main presentation was deep dyspareunia associated with a myofascial pain syndrome (group CPP). The subjects from the last group met some supplementary inclusion criteria: age of majority (18 years), no active pelvic infections and no general malignant, pelvic or psychiatric diseases. A total of 72 subjects were recruited, 24 per group, who provided their informed consent after they were acquainted with the nature of the study.The main demographic and clinical characteristics of the three groups are shown in Patients remained in a dorsal lithotomy position during the recording of the sEMG signal. Surface electromyography recordings were performed with adhesive electrodes over the perineum to assess PFM myoelectrical activity. They were chosen over intravaginal probes since such probes can be uncomfortable and provoke pain during their insertion, specially in patients that suffer from genital pain. This could hamper the acceptance of sEMG techniques by patients and thus its use in the clinical practice. Four disposable Ag/AgCl electrodes  were attached to both labia majora and two additional electrodes  were placed on both iliac spines, as To evaluate voluntary and involuntary PFM activity, clinicians designed a protocol of voluntary contractions that was performed by the subjects during each sEMG recording session consisting of 5 maximum voluntary contractions of 5 s each separated by 10 s of maximum relaxation. The signals were recorded from 2 min before the first contraction to 2 min after the last.sEMG recordings were off-line processed in MATLAB studio (version R2018b). A bipolar signal from each PFM side was obtained from monopolar recordings: B1 = M1 − M3 (right side) and B2 = M2 − M4 (left side). Spectral components of sEMG monopolar and bipolar signals outside the frequency range of the PFM activity were removed with two filters applied consecutively and symmetrically: a 17th order Butterworth low-pass filter (cut-off frequency: 450 Hz) and an 8th order Butterworth high-pass filter (cut-off frequency: 30 Hz). Such non-desired spectral components are related to motion artifacts and noise generated in the amplification system and at the skin-electrode interface, among others . An addi(1)5 segments of 5 s of single contractions, one for each maximum voluntary contraction performed by the PFM.(2)1 segment of 10 s of basal activity before the first contraction, when the PFM shows a maximum state of relaxation .(3)1 segment of 67 s from 1 s before the first contraction to 1 s after the last contraction, including the 5 contractions and the 4 resting periods.Different segments were mannually annotated in preprocessed sEMG signals acquired in each recording session to assess the voluntary and involuntary activity of the PFM:Intermittent artifacts were excluded from the annotated segments.Temporal, spectral, and non-linear parameters were computed from annotated sEMG segments to characterize the PFM activity of healthy women and CPP patients: root mean square (RMS), median frequency (MDF), Dimitrov index (DI), sample entropy (SampEn), and normalized cross-correlation (CC).x[n] with N samples is calculated as follows:RMS is a temporal parameter used to estimate the amplitude of the signal, consisting of the square root of the power of the signal . The RMSThe amplitude of the sEMG signal is related to the number of muscle fiber action potentials . Thus, aP(j) as the value of the power spectrum at frequency j and jf as the signal sampling frequency, its MDF can be expressed according to the following formulation:MDF is defined as the frequency that splits the power spectrum of the signal into two regions with the same total power. Considering Together with other estimators like the mean frequency or the dominant frequency of the power spectrum, MDF is a common index used to characterize the spectral content of sEMG signals. Variations in the value of MDF reflect modifications in the distribution of the signal power spectrum throughout its bandwidth, which can be associated with changes in the the conduction velocity of the action potential through muscle fibers and in the tissue filter effects, among other factors ,38. For k  of the signal , y[n]) delayed τ samples, CC can be calculated as follows:E is the expected value, * the conjugate transpose, x[n] and y[n], respectively, and xσ and yσ their standard deviations. When CC is computed from sEMG signals of two different muscles or regions in the same muscle, CC provides an estimation of the synchronization of their motor units [ signals . For twoor units . Its absCC was computed from one segment of the signal that included the five contractions performed by patients and the relaxing periods between them. Specifically, CC was calculated between segments of channels M1 and M3 (right side) and between segments of channels M2 and M4 (left side).For each session of recording, RMS, MDF, DI and SampEn were computed from segments of single contractions and relaxations annotated in bipolar signals . Values obtained from the 5 contractions were averaged, so that PFM voluntary activity was assessed according to a single value per parameter in each recording session. The influence of the group  on the characteristics of the pelvic sEMG signal was assessed, giving significant differences in the distribution of values between the groups for each PFM side and sEMG parameter. According to a two-tailed Kolmogorov-Smirnov test (significance level: 5%), the data did not follow a normal distribution, so a two-tailed Kruskal–Wallis test was performed under 5% of significance. A post hoc analysis based on the Bonferroni method was carried out to determine the pair of groups that showed significant differences in their sEMG characteristics.It can be seen in As The results of DI, shown in Box-whisker plots of the CC values obtained from sEMG signals on each PFM side of the three groups are shown in In this study, the PFM activity of women with different clinical characteristics was analyzed: patients with CPP associated with deep dyspareunia, healthy women over 35 (“mature”) and/or parous and healthy women under 35 (“young”) and nulliparous. Unlike most studies in the literature, the assessment was not limited to the analysis of the power of the PFM activity, but included other characteristics such as its spectral content, complexity or synchronization between different regions of the muscle to achieve a better understanding of the PFM electrophysiological condition.The RMS of the sEMG signal was computed to characterize the power of the PFM activity. Its value was higher in patients than in healthy women during maximum contractions and relaxation, especially when compared with mature/parous healthy women. Like us, several other authors have observed an increased amplitude of the sEMG signal in muscle at rest in women with PFM-associated pelvic pain ,17,48, wRegarding the power of the PFM activity of healthy subjects, we obtained higher values for younger-nulliparous women during PFM contractions and relaxation, especially on the right side. Pereira et al.  observedMDF values computed from sEMG recordings of CPP patients were lower than those from healthy women, significantly with those from mature/parous healthy women, and their DI values were higher. These differences reflect a shift of the sEMG power spectrum towards lower frequencies, which is usually associated with a reduction of the average conduction velocity of motor units. The lower conduction velocity of the action potential is a characteristic feature in peripheral fatigue . ConsideSampEn values were smaller in CPP patients than in healthy groups, especially in mature/parous women. Fatigue could once more account for the higher levels of organization found in the PFM activity of CPP patients. As several authors have suggested , the recp-values lower than 0.001 were obtained in all cases (results not shown). These results suggest that the rate of synchronization within the same side of the muscle is higher in the left than right PFM. To the best of our knowledge, the contrast between the electrophysiological behavior of each side of the PFM has not been previously reported in the literature. Differences in the density of innervations have rather been found between both sides of the PFM, specifically in the anal sphincter, as well as in the contribution of pudendal and levatorani nerves to the innervation of each of these [CC values were lower in patients than in healthy women in both groups. Some authors have previously pointed that the coordination between both PFM sides can be altered in pelvic floor disorders . Conversof these ,67,68. Hof these  observedof these , its preof these , so thatTo sum up, differences between CPP patients and their healthy counterparts (mature/parous group) were significant for almost all parameters during the contraction and relaxation of both muscle sides, while differences between CPP and healthy, young, and nulliparous subjects were only significant for two parameters and only on the left side. The discrepancies in the results obtained from both PFM sides were even more marked in healthy groups: while all sEMG characteristics of the right PFM at muscle rest were significantly different between the groups, there were almost no differences in the activity on their left sides. Although the PFM is regarded as a functional unit whose sides cannot be activated independently, they are innervated by different branches of the same nerve , so thatThe impact of laterality of pain on sEMG characteristics was analyzed in some preliminary studies (results not shown), but no significant relationships were found. Considering possible differences between the electrophysiological activity of both PFM sides, data were separated into different groups according to the patients’ laterality of pain , so that the absence of significant relationships could be a consequence of the small sample size of the study. On the other hand, the pathophysiology of chronic pelvic pain involves multiple and complex mechanisms associated with somatic or visceral tissues  and the central nervous system  . Thus, aOne of the main challenges of the present study was the recruitment of healthy women with similar demographic and obstetric characteristics to those of patients. Because of the lack of volunteers, we finally decided to compare the PFM activity of patients with that of women who met at least one of two requirements: (1) over 35 years old, (2) parous. Although aging, pregnancy and delivery are associated with significant changes in the pelvic floor’s anatomy and functionality ,59,62, tPFM activity was assessed in women with CPP associated with deep dyspareunia and healthy women with different demographic and obstetric characteristics from sEMG recordings. Unlike the vast majority of previous studies in this field, a more comprehensive characterization was made of the PFM activity in both physiological and pathological conditions. Not only power but also spectral content and complexity of the PFM activity were evaluated, as well as the synchronization of different regions on the same PFM side.The power of the PFM activity was greater in patients than in healthy women, especially when compared with mature/parous subjects, while their spectral content was shifted towards lower frequencies and complexity was lower. The synchronization of the lower and upper regions on the same PFM side was also lower in patients than in healthy women. These differences could be due to an increased number of motor units recruited and the muscle fatigue caused by overactivation of the PFM. In healthy conditions, the same trend of differences was observed when the PFM activity of young nulliparous women was compared with that of mature and/or parous subjects, which could be explained by histomorphological and neural changes associated with aging and parity.The significant differences found between PFM activity in patients and their healthy counterparts prove that sEMG can be a useful tool for CPP clinical management, as it can provide specialists with objective information on the electrophysiological PFM conditions, the role of musculoskeletal pelvic structures in CPP pathophysiology and lead to better diagnosis and efficient management of patients.