P < 0.001), pregabalin (P = 0.001) and methocarbamol (P = 0.002). The FIB group received lower doses of narcotics intraoperatively (P = 0.001), postoperatively (P < 0.001) and in total (P < 0.001). The FIB group also self-reported lower first pain scores upon arrival to PACU (P = 0.001) and experienced shorter PACU recovery times (P < 0.001). After controlling for differences between groups, patients who received an FIB required significantly lower amounts of narcotics, had shorter PACU times and lower first PACU pain score than those who did not (P < 0.001). No differences in complication rates were noted between groups. The use of FIB resulted in lower pain scores, reduced recovery time and decreased early postoperative narcotic requirements for patients undergoing hip arthroscopy for femoroacetabular impingement. Further study is required to validate these findings and determine the optimal approach to regional analgesia in this patient population.Fascia iliaca nerve blockade (FIB) has been previously described as an effective technique for reducing postoperative pain and opioid consumption after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). We hypothesize that an FIB will significantly reduce opioid consumption, pain scores and recovery time in our population. A retrospective observational study of 326 consecutive patients undergoing hip arthroscopy for FAIS at a single institution was performed. Patients were classified based on whether or not they received an FIB. Patient demographics, surgical details, medication details and 6-month postoperative outcomes were collected. The primary endpoint was the amount of narcotics required intraoperatively and in the postanesthesia care unit (PACU). Of the 326 patients included in the study, 37 received an FIB. No differences in sex, age or other surgical details were observed between groups. Patients receiving an FIB were more likely to receive celecoxib ( The incidence of hip arthroscopy procedures for treatment of femoroacetabular impingement syndrome (FAIS) has increased significantly since the mid-2000s. From 2006 to 2010, a 600% increase in procedure volume was observed in American Board of Orthopedic Surgery (ABOS) Part II examinees and the overall incidence increased from 3.6 per 100 000 in 2005 to 16.7 per 100 000 in 2013 , 5. AcroFor patients undergoing hip arthroscopy specifically, fascia iliaca nerve blockade (FIB) has been previously described as an effective technique for reducing postoperative pain and opioid consumption , 9. FIBsThis study was deemed institutional review board exempt by the institution’s clinical research committee. A retrospective observational study of consecutive patients undergoing hip arthroscopy for FAIS was performed. All surgeries were performed by a single surgeon at a single institution from July 2018 to January 2021. All patients were confirmed to have a cam or pincer impingement that was surgically treated with bony resection along with repair or reconstruction of the labrum. Patients who were under 18 at the time of surgery, pregnant or prisoners were excluded.All surgeries were performed on an outpatient basis under general anesthesia; regional anesthesia with FIB was performed at the discretion of the surgeon and anesthesiologist for postoperative pain control. Preoperative multimodal pain management was implemented for appropriate patients in March 2019 and consisted of celecoxib, pregabalin, and robaxin given in the preoperative holding area. Patients received some or all of these medications at appropriate dosages based on their individual medical histories. Intraoperative local anesthesia was used for all patients at the end of the case with deep infiltration into the joint space. Patients that did not receive an FIB were injected with 30 ml of 0.5% bupivacaine and patients that did receive an FIB were injected with variable amounts of 0.5% bupivacaine based on their weight and taking into account the amount of local anesthetic that they had already received with the block. All patients were subject to the same rehabilitation protocols with the exception of postoperative hip bracing, which was discontinued for most patients in October 2020. All patients began a supervised rehabilitation program during Postoperative Week 1. Initial range of motion (ROM) restrictions are as follows: hip flexion from 0–120 weeks 0–3, abduction 0–45 weeks 0–3 and no external rotation for 2 weeks. Strength and ROM with restrictions are progressed as per protocol. All patients are toe touch weight bearing with crutches from weeks 0 to 3 and then progress to weight bearing as tolerated and wean from crutches.Fascia iliaca blocks were performed by a select group of anesthesiologists with prior training in this technique. Blocks were performed using ultrasound guidance using the technique described in the New York School of Regional Anesthesia guidelines . Patientt-tests for continuous variables and chi-square testing for categorical variables. The Fisher’s exact test was used in place of chi-square when the assumptions of chi-square testing were not met. A subgroup analysis comparing OMME across four categories of whether or not multimodal analgesia was used and whether or not a block was used was performed using one-way analysis of variance with post hoc Bonferroni correction to compare between-group differences. Multiple linear regression was then performed to evaluate whether the use of an FIB was associated with decreased OMME requirements after controlling for differences between the groups. All statistical analyses were performed in SPSS version 27 .Patient demographics and operative details were extracted from the electronic medical record using structured query language. Surgical details, pre-, intra- and postoperative medication details, 6-month postoperative outcomes, and patient-reported outcomes were collected by manual chart review. Patient-reported outcomes [Patient-Reported Outcomes Measurement Information System Global Health (PROMIS-GH) physical health and Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR)] were collected on a voluntary basis and not available on all patients. Lower extremity functional score (LEFS) was only available on patients who attended physical therapy through the hospital-based practice and thus not available on all patients. The primary endpoint was the level of narcotics required intraoperatively and in the PACU. Opioid consumption was converted to oral morphine milligram equivalents (OMME). In addition, preoperative multimodal pain medications and muscle relaxants received in the preoperative holding area were recorded so that they could be controlled for in multivariate analysis. Patients were then grouped based on whether or not they received an FIB, and univariate comparisons were performed using two independent sample 2, P = 0.044). No differences in other surgical details including the proportion of patients with American Society of Anesthesiologists Score (ASA) ≥ 3, reconstruction or bony resection type, or operative time were observed between groups  did not receive an FIB and 37 (11%) received an FIB. No differences in sex or age were observed between groups, and patients receiving an FIB had lower body mass indexes (BMIs) on average (25.7 ± 4.4 vs. 27.7 ± 5.9 kg/mn groups .P < 0.001) and pregabalin . Similarly, a higher proportion of patients in the block group received preoperative methocarbamol   .P = 0.001), postoperatively  and in total . Patients in the FIB group also self-reported lower first pain scores upon arrival to PACU , but no difference was found when comparing the final pain score prior to discharge. PACU recovery times were also shorter in the FIB group   .P < 0.001) (P = 0.058) or between patients who received a block with or without multimodal analgesia (P = 1.000). However, patients receiving a block without multimodal analgesia and with multimodal analgesia all received less OMME than patients in the no-block groups . After controlling for differences between groups—BMI, celecoxib, pregabalin and methocarbamol usage, patients who received an FIB required significantly less OMME , had significantly lower first PACU pain scores , and spent less time in PACU  than those who did not  . No betw did not .The use of FIB in patients undergoing hip arthroscopy surgery was associated with reduced early postoperative opioid consumption, decreased postoperative pain scores and decreased time spent in the PACU in our patient population. Of note, the reduction in recovery time of 41 min, the reduction in first PACU pain score by almost 2 points and the reduced opioid requirement of over 25 OMME after risk adjustment are of particular operational and clinical significance. We also found no increase in postoperative complications, specifically no falls in the patients that received a block, and no differences in patient-reported outcomes between groups. Based on these findings, we suggest that FIB can successfully be incorporated into perioperative protocols for patients undergoing hip arthroscopy for FAIS and may improve the early recovery process.The findings of this study are consistent with several prior studies supporting the efficacy of FIBs. A retrospective study including 716 patients who underwent hip arthroscopy found that PACU time and opioid consumption were reduced due to a supra-inguinal FIB, but pain scores did not reach statistical difference . AnotherAlthough our findings add to a growing body of literature supporting the use of FIBs, FIBs are not a standard of care for hip arthroscopic procedures. Other authors have questioned the efficacy of regional anesthetics. One study found that FIBs had no statistical difference with regard to pain and patient satisfaction between an FIB group of 27 subjects and a no-block group of 33 subjects. Pain scores were recorded 1, 2, 4 and 7 days following surgery . Similaret al. comparing QL blocks and multimodal analgesia to multimodal analgesia alone, no significant difference was found between groups [et al., the results of the current study support the assertion that FIB and PENG blocks hold promise as effective methods of perioperative pain control in patients undergoing hip arthroscopy [Alternative regional anesthesia methods that have been described for patients undergoing hip arthroscopy include lumbar plexus, quadratus lumborum (QL) and pericapsular nerve group (PENG) blocks. In a study comparing the efficacy of an FIB group (25 subjects) to a lumbar plexus block group (23 subjects) following hip arthroscopies, FIBs were found to be easier to learn and implement and were more effective at reducing postoperative pain . In a ren groups . Anothern groups . Originan groups . Howevern groups , 22. In a priori power analysis performed, it is possible that our population of patients is not representative of the broader population of patients undergoing hip arthroscopy for FAIS. Second, there is potential that selection bias exists as utilization of FIBs was at the discretion of the anesthesiologist in consultation with the patient. Third, other confounding factors may have influenced early postoperative outcomes including psychosocial factors which were not accounted for in this study. Although we attempted to control for these factors using multivariate methods, especially differences in the use of multimodal pain management medications, there is potential that other undocumented factors influenced pain and recovery.There are multiple limitations of the current study. As a single-institution, single-surgeon observational cohort study with no The use of FIB resulted in lower pain scores, recovery time and early postoperative narcotic requirements for patients undergoing hip arthroscopy for FAIS. Further study is required to validate these findings and determine the optimal approach to regional analgesia in this patient population.


TM instrument on the hands and feet during SCS on and off states. Difference scores in skin conductance between patients and age- and sex-matched healthy controls were calculated. Normal sudomotor function at the painful lower limb was revealed for 61% of the patients when SCS was activated. Skin conductance levels were not altered between on and off states of SCS. Differences in scores between patients and healthy controls were significantly different from zero. This study showed that SCS does not influencing the sympathetic nervous system in patients with FBSS, as measured by skin conductance levels. Moreover, it suggested that there is no normalization of the functioning of the sympathetic nervous system, despite the effectiveness of SCS to reduce pain intensity.Despite the well-known clinical effects of spinal cord stimulation (SCS), the mechanisms of action have not yet been fully unraveled. The primary aim of this study was to measure whether electrochemical skin conductance, as a measure of peripheral sympathetic autonomic function, is altered by SCS. A second aim was to compare skin conductance levels of patients with failed back surgery syndrome (FBSS) with age- and sex-matched healthy controls. Twenty-three patients with FBSS treated with SCS participated in this study. Sudomotor function was measured with the Sudoscan In many patients with failed back surgery syndrome (FBSS), the origin of the persisting element in the pain experience is still unknown, which makes targeted treatment difficult to deliver ,2. SpinaIn healthy individuals, a dynamic balance between the excitatory sympathetic part and inhibitory parasympathetic part of the autonomic nervous system is present ,24. In cTM is a simple, non-invasive sudomotor test that allows measurement of the sweat gland function [TM is used in a broad range of populations, including patients with COVID-19 [Sudorimetry, i.e., measuring the function of sweat gland innervation, specifically evaluates the peripheral sympathetic system . In contfunction . It is efunction ,34, can function . This mefunction . In patifunction ,36. CurrCOVID-19 , multiplCOVID-19 , and ParCOVID-19 .TM, is altered by SCS in patients suffering from FBSS. A second aim was to compare skin conductance of patients with FBSS who receive SCS to an age- and sex-adjusted normal population.The goal of this study was to further unravel the mechanisms of action of SCS by evaluating whether SCS can influence the peripheral sympathetic nervous system; therefore, the first aim was to measure whether electrochemical skin conductance, as measured with the SudoscanPatients with FBSS who received treatment with SCS at the department of Neurosurgery of Universitair Ziekenhuis Brussels were invited to participate in this study. According to routine clinical care at our center (and regulated by reimbursement rules), all patients had a standard clinical visit regarding their treatment progress every 6 months. Selection of patients was based on those FBSS patients who were scheduled for a 6 month SCS follow-up visit. Patients were allowed to take part in this study if they were at least 18 years old. Patients were not allowed to take part in the study if they had impaired skin integrity at the fingers and feet or if they had been previously diagnosed with major psychiatric problems.clinicaltrials.gov (NCT04668482). All patients provided written informed consent before participation. The study was conducted according to the revised Declaration of Helsinki (1998).The study protocol was approved by the central ethics committee of Universitair Ziekenhuis Brussels (B.U.N. 1432020000073) on 27 May 2020. The study was registered on This was an experimental study, consisting of a single outpatient visit. All patients who took part in this study were instructed to switch off SCS 12 h before their study visit. During the study visit, skin conductance was first recorded when SCS was still switched off. Afterwards, patients were asked to provide a pain intensity score. After this measurement, patients had to switch their neurostimulator on, followed by a rest period of 30 min. A second evaluation of skin conductance and pain intensity reporting was conducted after this 30 min break. Due to the pain-relieving effects of SCS, patients could not be blinded to the study conditions.All patients were asked to confirm that they switched off SCS 12 h before the study visit. This statement was controlled by evaluating whether SCS was effectively switched off  when patients presented themselves for the study visit.To assess the current pain intensity, the visual analogue scale (VAS) was used for lower back pain and leg pain separately. For the VAS, a 10 cm line on paper was provided to all patients, representing a continuum between no pain and maximal pain. Pain intensity is expressed here in mm on a scale from 0 to 100. Patients completed this questionnaire twice; once when SCS was switched off and once when SCS was activated. The VAS pain score is a reliable and valid tool that is sensitive to change ,41,42,43The Medication Quantification Scale III (MQS) was used to quantify and monitor different drug regimens used to treat a variety of pain conditions . This toTM  evaluates sudomotor function through the measurement of electrochemical skin conductance (ESC) using reverse iontophoresis and chronoamperometry [The Sudoscanerometry . It reflerometry . As sucherometry . This iserometry . At low erometry . During erometry . Accordierometry . All meaReference data for ESC were taken from the study by Vinik et al. (2016), in which data from 1350 healthy study participants were collected and analyzed . The selSample size calculation was performed using G*Power 3.1.3  based on the sympathetic skin response of healthy controls versus patients with chronic lower back pain and FBSS . Mean amp-values of 0.05 or less were considered statistically significant. No missing data were observed, meaning there was no need for imputation strategies. Normality was evaluated with the Shapiro–Wilk test and QQ-plots, while equality of variance was evaluated with Levene’s tests. Descriptive statistics are provided as means (±SD) or as medians (first and third quartile). A simple regression model was built with pain intensity scores as the outcome variables and the on and off states of SCS and pain location (low back or leg) as explanatory variables using an automatic step function.All analyses were performed in R Studio version 1.2.5019 (R version 3.6), except for the mixed models, which were constructed with SAS version 9.4. Here, ESC values between SCS on and off states were compared with Wilcoxon tests for hands and feet separately. Additionally, mixed models were constructed with ESC values as outcome variables and SCS condition, age, MQS score, and pain intensity scores as exploratory variables. Individual difference scores between patients and age- and sex-matched healthy persons were calculated by subtracting the score of the matched control from the patient score. A negative difference score indicated that the patient score was lower than the score of the matched control. Single-sample Wilcoxon tests were applied to evaluate whether the difference scores were significantly different from zero.2. The median duration that patients were implanted with SCS was 3 (Q1–Q3: 2–7) years. The median score on the MQS was 11 (Q1–Q3: 6.2–16.1). All patients were Caucasians.In total, 23 patients were included in this study. All experiments were conducted on 12 December 2020. Twelve males and 11 females took part in this study. Patients had a mean age of 55.0 (SD: 9.2) years and a median BMI of 27 (Q1–Q3: 26.0–29.5) kg/mp < 0.001) on pain intensity. The expected pain intensity score  for a patient with FBSS when SCS was deactivated was 56.67 (95% CI from 48.89 to 64.46). When SCS was activated, the expected pain intensity score was 24.98 (95% CI from 13.97 to 35.99). Pain location (lower back or leg) was not withheld in the final model .Additionally, 23 healthy controls were matched to the patients in our study population based on sex and age category.p = 0.19), non-painful lower limb , upper limb on the painful side , or upper limb on the non-painful side . The results of these measurements are presented in The median ESC values did not significantly differ between SCS on and off states for measurements of the painful lower limb . The results of the model are presented in Mixed models for ESC on the lower limb on the painful side resulted in a significant effect of SCS condition  patients showed normal sudomotor function, 7 (30%) patients presented with moderate sudomotor dysfunction, and 2 (9%) with severe sudomotor dysfunction with ESC recordings of the painful lower limb. Recordings for the hand (painful side) revealed 12 (52%) patients with normal sudomotor function, 10 (44%) with moderate sudomotor dysfunction, and 1 (4%) with severe sudomotor dysfunction during SCS.p = 0.009) and upper limb . The median ESC values for healthy controls were 82.70 (Q1–Q3: 81.35–82.90) for the lower limb and 73.80 (Q1–Q3: 73.05–75.50) for the upper limb, based on the data produced by Vinik et al. (2016) . For patThis study aimed to evaluate whether the autonomic nervous system, and more specifically the peripheral sympathetic system, was altered by SCS. By experimentally manipulating SCS conditions (SCS on versus off), the results indicated that skin conductance is not influenced by SCS. Additionally, skin conductance in patients with FBSS who were treated with SCS was compared to that of healthy controls. A statistically significant difference of −8.00 (Q1–Q3: −18.00–2.55) at the lower limb and −13.80 (Q1–Q3: −18.45–2.90) at the upper limb was found between both groups in favor of healthy controls. This indicates that in normal daily situations (SCS activated), the skin conductance of patients with FBSS was still different from the skin conductance of healthy controls, despite the treatment.TM to measure ESC indicated lower values in patients with fibromyalgia [Previous evaluations of the functional impairment of non-myelinated postganglionic sudomotor sympathetic fibers in patients with chronic lower back pain and FBSS by measuring sympathetic skin response (SSR) revealed alterations in SSR  in patients compared to healthy controls . Prolongomyalgia , Fabry domyalgia , and psoomyalgia  comparedomyalgia ), ESC vaomyalgia . Indeed,omyalgia . Pain inConversely, it is also plausible that SCS provided at the thoracic level does not influence the sympathetic system but only the parasympathetic system. Previous studies suggested that the presence of chronic pain induces changes in the balance of the autonomic nervous system ,54. IndiPatients who were included in this study were implanted with SCS for 3 (Q1–Q3: 2–7) years. The initial effectiveness of SCS generally declines over time due to growing tolerance of the central nervous system in around 20–40% of patients ,62. If tTM was used to evaluate sweat gland function by measuring sweat chloride concentrations using reverse iontophoresis and chronoamperometry [In this study, the Sudoscanerometry , withouterometry  in the serometry  . Additierometry . On the erometry . Recentlerometry . A signierometry . By expeerometry ,73, poteerometry ; therefoPrevious research studies have already explored the electrochemical behavior of stainless steels (of which the electrodes of the Sudoscan are composed) by mimicking the behavior of electrodes in contact with sweat through stainless steel 304 L and synthetic buffer carbonate solutions containing chloride, lactate, and urea . The resTM, was used to limit the influence of the lack of blinding. Another limitation of this study is that the ESC data of patients with FBSS were compared with the ESC data from historical healthy controls. Finally, in this study, an experimental manipulation of the SCS status was performed in all patients. Skin conductance responses can be directly altered related to manipulating the device status or by indirect effects, such as increased pain intensity levels or alterations in psychological factors when SCS is switched off. The potential mediating effect of pain intensity or claims of causality cannot be made with the current study design.This study also had some limitations. Due to the longer wash-out period compared to the wash-in period for SCS, patients were not blinded to the stimulation conditions. An objective measurement instrument that does not rely on self-reporting of patients, i.e., SudoscanSudomotor function, as an indicator of peripheral sympathetic autonomic function, is not altered when manipulating SCS conditions in patients with FBSS. Moreover, the electrochemical skin conductance in patients with FBSS who are receiving treatment with SCS is different from skin conductance in healthy controls, indicating a lack of normalization in this population. The current findings lead to the hypothesis that SCS only influences the parasympathetic system, without a direct alteration of the sympathetic system.


To investigate the efficacy of intraoperative superior hypogastric plexus (SHP) block for postoperative pain relief in patients undergoing a cesarean section.One hundred and fifteen pregnant women scheduled for an elective cesarean under general anesthesia were randomly divided into an SHP block (n = 65) and a control group (n = 50). SHP block was administered with bupivacaine injection. The controls received saline injection in the SHP area. Postoperative pain was assessed by the 10-cm visual analog scale (VAS). The presence of side effects and complications, including opioid or non-steroidal anti-inflammatory drugs (NSAID) requirement, gastrointestinal function, nausea, and vomiting were evaluated.P < 0.001) and required a significantly lower rescue dose of NSAID or opioids .The SHP block group had significantly lower VAS scores 2, 6, 24, and 48 hours postoperatively (SHP block may be an effective and safe pain relief treatment after a cesarean section. Cesarean section is a rescue surgical procedure mostly performed in order to save the fetus's life or avoid labor complications . Rising Insufficient pain relief is a common complaint among inpatients. In a Spanish study, 30%-70% of the patients reported moderate to severe pain after surgery . Among wIn this regard, a combined postoperative pain management has been recommended for cesarean delivery. Effective analgesia is achieved by opioids administration either by patient-controlled analgesia or neuraxial injection -9. DiffeSuperior hypogastric plexus (SHP) block has been used for treatment of postoperative pain after gynecologic procedures -13. The This case-control study was conducted at Zeynep Kamil Women and Children Diseases Education and Research Hospital between January and March 2019. The Institutional Review Board (101/5.5.2017) approved the study. Informed verbal and written consent were obtained from all participants.The study enrolled women aged between 18 and 40 years with term singleton pregnancies and no history of cesarean section or abdominal surgery scheduled for elective cesarean section. General anesthesia was performed to allow us to more accurately assess the procedure's efficacy in the early postoperative period. The study enrolled only Class 1-2 patients according to the American Society of Anesthesiologists (ASA) Classification. Patients were randomly allocated into two groups. The allocation sequence was generated by a random number table, and group allocation was concealed in sealed, opaque envelopes, which were not opened until operation. During the operation, the envelope was opened by a nurse outside the operating theater. The nurse prepared a blind syringe with the study drug, which was then transferred to a sterile bowl in the operating room and injected. Bupivacaine and saline are both colorless and not possible to identify by visual appearance or smell. The envelope was then sealed again and not opened until the study was concluded. The patients, anesthesiologists, and nurses providing postoperative care were blinded to group assignment. The control group received a saline injection in the SHP area. We excluded patients with bleeding disturbances, chronic pelvic pain, a history of opioid or NSAID allergy, asthma, diabetes, liver or kidney diseases, drug or alcohol abuse, and pregnancy-induced hypertension. The patients who underwent an emergency cesarean section were also excluded. The indications for primary elective cesarean were breech presentation and maternal fear of vaginal birth.The routine standardized general anesthesia and perioperative analgesia protocol were applied without premedication. General anesthesia was induced by propofol 2.5 mg/kg and rocuronium 0.6 mg/kg. Following adequate muscle relaxation, endotracheal intubation was performed. Anesthesia was maintained by sevoflurane 0.6 MAC in oxygen/air. Sevoflurane concentration was adjusted according to the hemodynamic response. For perioperative analgesia, 15 mg/kg paracetamol (max 1 gr) and 20 mg tenoxicam were given intravenously approximately 30 minutes before the surgery ended.The surgery was carried out through a Pfannenstiel incision. After the newborn and placenta delivery, a uterine incision was closed by exteriorizing the uterus. Upon achieving hemostasis, the SHP block was carried out retroperitoneally following the injection of either 20 mL of bupivacaine 2.5 mg/mL or saline 9 mg/mL in the SHP area  Figure .At the post-anesthesia care unit (PACU), the women were monitored for the degree of sedation, hemodynamic and respiratory stability, pain, and nausea. When the patient was awake with stable vital signs, she was discharged to the ward. Postoperative pain was evaluated with the 10-cm visual analog scale (VAS), where 0 indicates no pain and 10 indicates the worst pain. The patients were asked to rate their pain when lying still in bed (at rest) and on movement. VAS scores were assessed and recorded by a pain nurse at 2, 6, 24, and 48 hours after surgery. The routinely used analgesics for pain relief in the PACU and surgical ward were the nonsteroid anti-inflammatory drug (NSAID) diclofenac sodium and the opioid pethidine. The VAS score ≥4 is considered a pain level that should be treated . The patThe primary study outcome was the pain score at rest and on movement 24 hours after surgery. The secondary outcomes were the pain scores at rest and on movement 2, 6, and 48 hours after surgery; opioid or NSAID requirement; return of gastrointestinal function; the rate of nausea and vomiting as a side effect; and surgery duration.A preliminary power analysis indicated that a sample size of 70 patients (35 for case group and 35 for control group) provided a statistical power (1-β) of at least 80% at α = 0.05 for the detection of 1-cm differences in VAS scores between the two groups at 24 hours after surgery.2 test was used to compare the categorical data. The analysis was performed with SPSS for Windows, version 22.0 .The normality of distribution was assessed with the Kolmogorov-Smirnov test. The parametric data were presented as means and standard deviations, the non-parametric data as median and range, ratio, and the categorical data as counts and percentages. The Mann-Whitney U test was used to compare the continuous data, while the χThe study group consisted of 65 patients and the control group consisted of 50 patients, a total of 115 patients . The meaP = 0.002, P < 0.001 respectively), as well as 2, 6, and 48 hours after surgery (P < 0.001) (P < 0.05) (The study group had significantly lower VAS scores at rest and on movement 24 hours after surgery (< 0.001) , Table 1 < 0.05) .P = 0.003, P < 0.05, respectively). They also had a significantly lower incidence of nausea and vomiting (P < 0.05) (P < 0.001), and significantly shorter time to the first passing of gas after surgery (P = 0.009).In the control group, 94% of the patients required rescue NSAID dose and 48% required opioids for analgesia. In the study group, these rates were only 56.5% and 13.9%, respectively. The study group needed a significantly lower rescue dose of NSAIDs or opioids ( < 0.05) , signifiIn this study, SHP block was shown to effectively control pain after a cesarean section. Postoperative pain scores and rescue dose analgesic requirement significantly decreased in the study group, while no complications and side effects were reported.The main purpose of postoperative pain relief after cesarean section should be to safely and effectively provide maximum pain control with minimal side effects to the mother and baby. A few studies have investigated SHP block in patients undergoing a hysterectomy -13. AytuPostoperative pain has a visceral and a somatic component. SHP block is mainly used to control the visceral pain . AccordiSHP block was first introduced in 1990 in patients with pelvic pain secondary to cancer . The comSome authors reported no difference in the rates of postoperative nausea and vomiting between the SHP block group and controls ,12. In cPain control allows mothers to breastfeed more comfortably and care better for the baby . Severe This is one of the rare studies investigating the efficacy of the SHP block after a cesarean section. The main study strength is the inclusion only of patients undergoing primary elective cesarean section. This enabled us to more homogeneously evaluate pain scores. As a limitation, we performed the SHP block only in patients under general anesthesia to clearly observe the efficacy of the method. However, considering the wide use of spinal anesthesia in cesarean sections, further studies with both types of anesthesia are needed. This intervention should also be assessed in various populations, such as in women with previous surgery. We also did not collect the data on long-term complications of the procedure.In conclusion, the SHP block may be a safe alternative analgesic method for use after a cesarean section. This method not only lowered the postoperative pain scores, but also showed fewer side effects compared with opioids. Still, larger studies are needed to confirm these results.


Bariatric surgery produces significant and quantifiable reductions in back pain. However, there is a lack of information on the association of weight changes after bariatric surgery with changes in pain score. We aim to evaluate the impact of bariatric surgery on back pain in obese patients and to address the association between changes in body mass index (BMI) and pain score. In obese patients eligible for bariatric surgery, the changes in pre- and post-operative pain scores, assessed by the Numeric Rating Pain Scale (NPS) or Visual Analogue Scale (VAS), were considered as primary outcomes. Mean difference (MD) and their 95% confidence intervals (CI) were evaluated. Eight cohort studies were included in the analysis of 298 obese patients undergoing bariatric surgery. All studies showed a reduction in back pain, with a mean change of −2.9 points in NPS and of −3.8 cm in VAS. There was a significant reduction in back pain (NPS: (MD = −3.49) ; VAS: MD = −3.75, ) and BMI ) following bariatric surgery. No significant relationship between BMI change and decrease in clinical scores could be established. However, it was evident that bariatric surgery had a significant effect on back pain scores in severely obese patients. Ideally, a prospective study including spinal imaging, inflammatory markers, a longer follow-up period, and larger study groups with a randomized control group needs to be performed. Obesity is associated with an increased risk for type 2 diabetes, hypertension, cardiovascular diseases, cancer and musculoskeletal diseases, including low back pain (LBP) [Obesity is a growing health problem worldwide. The WHO reported that about 1.9 billion adults were overweight and 600 million adults were obese in 2016, numbers which continue to rise over the years [in (LBP) . Among oin (LBP) ,6. Accorin (LBP) ,8,9,10. Over the past decade, bariatric surgery has emerged as an attractive, evidence-based option that offers significant and durable weight loss and improved health outcomes for those with clinically severe obesity. American Society for Metabolic and Bariatric Surgery guidelines suggest the position statement on consensus for BMI (35 to 40 without comorbidities or 30 to 35 with significant comorbidities) as an indication for bariatric surgery ,12. BesiIn order to understand the clinical significance of LBP after bariatric surgery, the main objectives of the present review are (1) to evaluate the impact of bariatric surgery on the weight of severely obese patients; (2) to identify the effect of bariatric surgery on the pain score and secondary outcomes (disability and disc space height); and (3) to evaluate the association of weight change with pain score or disability score change if any.The literature was searched in accordance with preferred reporting information for systematic reviews and meta-analyses (PRISMA) guidelines . The onl(1)Randomized controlled trials (RCT) and observational studies of any bariatric surgery .(2)2, or a BMI ≥ 35kg/m2 with comorbidities, undergoing primary bariatric surgery.Studies which enrolled adult obese patients with a BMI > 40 kg/m(3)Studies which reported the pain intensity change of the lower back with the Numeric Rating Pain Scale (NPS) or Visual Analogue Scale (VAS) before and after bariatric surgery.(4)Studies which reported a follow-up of at least 3 months.Meta-analyses, systematic reviews, editorials, in vitro biomechanical studies, and studies looking into LBP caused by pathological entities were excluded.(1)Primary outcome: the change in the pain intensity score of the LBP before and after bariatric surgery, as measured in VAS or NPS, and the change in BMI before and after bariatric surgery.(2)Secondary outcomes: the change in disc space height, back-specific disability questionnaires , and Waddell Disability Index) and pain pressure threshold (PPT) before and after bariatric surgery; the association between the back-specific disability questionnaires (Roland–Morris score or Oswestry Disability Index (ODI) or Waddell Disability Index) and BMI changes following bariatric surgery for severely obese patients.The following outcomes measures were assessed in this review:Two reviewers (FWK and XLC) screened the titles and abstracts following the inclusion and exclusion criteria. In all of the potential eligible studies, the full text was reviewed. When consensus could not be reached between the reviewers, a third reviewer (AD) was consulted to resolve the disagreement.Two reviewers (FWK and XLC) extracted data independently. The reviewers collected the following data: methods , participants , interventions , and outcomes .The Newcastle–Ottawa Scale (NOS) was used to assess the methodological quality of the included observational studies . The NOS2) statistic was used to measure heterogeneity among the trials. I2 < 50% implied homogeneity, and the analysis included a random-effects model by the DerSimonian–Laird method. I2 > 50% indicated heterogeneity and, consequently, a fixed-effects model was used according to the Mantel–Haenszel method. We conducted subgroup analysis and sensitivity analysis to assess the impact of heterogeneity. MD and 95% confidence intervals (CI) were reported. A forest plot was used to calculate the results. Publication bias was assessed by funnel plot symmetry using the Begg–Mazumdar test. The statistical significance was set at 5% (α = 0.05).Mean difference (MD) and standard deviation (SD) were calculated. To calculate MD, the mean change for the post-operative data was subtracted from the mean change for pre-operative data. The SD was generated by dividing the standard deviations by the square root of the study population. The chi-squared  system was used to evaluate the levels of evidence, the quality of assessment and the results from data extraction . The quaThe literature search is illustrated in the PRISMA flow diagram . Eight oAmong a total of 298 patients in the eligible studies, the median of the mean age was 44.1 years, of which 75.8% were female. The mean overall follow-up was 42.4 weeks (range from 13 to 104.4 weeks).The bariatric interventions in these studies included Roux-en-Y gastric bypass ,22,25,26The methodological quality of these cohort studies was assessed using the NOS-tools in All of the studies show a favorable improvement in back pain intensity scores (NPS and VAS) after bariatric surgery. Based on all of the eight included studies, the change in LBP after bariatric surgery showed a 40% to 86.7% reduction )  20,21,2,25,26,27We obtained subgroup analysis based on a different pain score questionnaire. Four studies measured pain intensity using NPS ,22,24,25I2 = 9.2%; VAS group: MD = −4.58 , I2 = 0.0%).A sensitivity analysis of the results is listed in 2 (range from 42.8 to 52.25 kg/m2) and the mean reduction in BMI was 25.9% (ranged from 16.8% to 30.5%). There was a statistically significant reduction in mean BMI following bariatric surgery . We rated the quality of evidence as moderate due to inconsistency in findings and the large magnitude of effect.Six studies reported the initial and post-operative BMI ,25,26,27 surgery  (six stu2 = 84.5%), number of patients  and follow-up period . It showed no effect on the heterogeneity.As there was significant heterogeneity, we obtained subgroup analysis based on publication date . Based on different pain score questionnaires for subgroup analysis, no significant association was found between the change in BMI and decrease in clinical scores . The large magnitude of effect upgraded the low-quality evidence from the cohort studies to high-quality. However, inconsistency in findings downgraded the quality of statistically significant difference between the initial and post-operative BMI to moderate.Three of the eight studies investigated the disability outcomes: (a) Roland–Morris disability questionnaire (RMD) ,27, (b) The intervertebral disc space height was examined by Lidar et al. in 30 morbidly obese patients undergoing bariatric surgery to determine the effect on axial and radicular pain, intervertebral disc space height, and quality of life one year after surgery . One yeaHere, we have performed meta-regression for the first time addressing the association of mean back pain changes with BMI change following bariatric surgery on obese patients. We identified a total of eight cohort studies with 298 obese patients who underwent bariatric surgery including Roux-en-Y gastric bypass, sleeve gastrectomy, gastric banding, and duodenal switch. All studies reported BMI and pain scores for back pain before and after bariatric surgery.Results of our meta-analysis revealed that BMI in obese patients was statistically significantly lower following bariatric surgery across all eight included studies, which is consistent with previous recommendations on the use of bariatric surgery for obesity ,29. MeanIn exploring the causation of improved back pain following bariatric surgery, some authors have proposed many different etiological factors, such as mechanical change or musculoskeletal change and biochemical change ,31,32,33Weight loss following a healthy diet and effective physical activity is also likely to have a positive effect on back pain symptoms. Maintaining a healthy body weight may be one of the factors preventing the occurrence of LBP. Although all of the included studies reported a significant reduction in BMI and back pain score following bariatric surgery, there is still no consensus on the association between the reduction in BMI and the decrease in pain score ,21,23,26Although we did not find a direct linear correlation between the BMI reduction and the decrease in back pain following bariatric surgery, we think that this finding may reflect the major limitation of our study where the potentially included “population” (obese patients with back pain) studied were excluded for not reporting on back pain; hence, the true correlation of poor clinical results to BMI changes remains undetermined. Another possible explanation is that the lack of association may be explained by the observation that in severely obese patients, the disc and facet joints are exposed to many years of considerable axial loads, combined with normal aging and dehydration of the disc. These changes, in turn, may lead to BMI recovery, causing them to behave in a stepwise rather than in a linear fashion. These changes indicate that even if the BMI is reduced, the state of back pain by intervertebral disc degeneration will not change.There are several limitations to this study that should be considered. Firstly, this meta-analysis only included prospective observational studies without control groups. The analysis resulted in too much heterogeneity between the pooled studies. A fix effect model showed a significant reduction. However, with the low-quality of the results, a definite conclusion cannot be drawn until more studies become available. Secondly, the range of follow-up period was large (from 3 to 24 months). There is a great heterogeneity in the time of data collection of the post test. Thirdly, the mean follow-up of the studies was short. No conclusion about long-term effects and the durability of the back pain problems can be made. Fourthly, the history of the patients’ back pain problems is unknown in most studies. Fifthly, meta-regression analysis describes observational associations across trials because comparisons of trial-level characteristics lack the benefit of randomization to support causal interpretation of findings. Consequently, associations between trial-level characteristics and effects of interventions are subject to the same limitations as findings from observational studies, such as bias by unmeasured confounding. Lastly, not all included studies reported the loss in patients follow-up. Still considering the limitations, more research is needed to establish if bariatric surgery should be considered prior to spinal surgery in morbidly obese patients solely with back pain.From this meta-analysis, the data of back pain improvement following bariatric surgery are encouraging. However, considering the high heterogeneity, the evidence is of low quality. More research is needed to draw a correct weighted conclusion. Ideally, a prospective study including spinal imaging, inflammatory markers, longer follow-up periods, and larger study group with a randomized control group needs to be performed. The relationship between weight loss and reduction in back pain is complex but remains scientifically unclear. To further understand how and why bariatric surgery could reduce the back pain problems of obese patients, the mechanical and inflammatory effects of obesity on the spine should be better understood.


Chronic nonspecific low back pain (LBP) is one of the common health issues. Hamstring tightness contributes to the development of LBP. This study aimed to investigate the acute and short-term effects of deep dry needling (DN) in patients with chronic nonspecific LBP and hamstring muscle tightness.  A single-group pretest-posttest clinical study design was followed. The outcome measures were the visual analog scale (VAS), passive knee extension (PKE) test, finger-floor distance (FFD) test, and functional rating index (FRI). Patients underwent one session of deep DN of three points on both hamstring muscles, each point for one minute. Patients were assessed before (T0), immediately after (T1), and one week after DN (T2). The FRI was assessed at T0 and T2. d = 1.25) and PKE hamstring tightness were obtained  at T2. Medium effect sizes were obtained for FFD (d = 0.45) and FRI (d = 0.72) at T2.  Ten women with a mean age of 21.1 years (SD = 1.6) participated in the study. Significant large effect sizes in VAS pain reduction (IRCT20180511039612N1. A single session of deep DN improved pain and function and increased hamstring flexibility. This pilot study supports the use of DN in patients with LBP and hamstring tightness; however, future research with a rigorous study design of randomized controlled trial is required to confirm the findings. This trial is registered with  Low back pain (LBP) is one of the common health conditions, with a prevalence of 1.4–20% in developed countries and a global prevalence of 9.4% . LBP leaMuscle tightness contributes to musculoskeletal conditions. Previous studies have found that hamstring tightness is a contributing factor to LBP . Tightnen = 29) and control group (n = 27); both groups had received 8 weeks standard rehabilitation  before entering the DN trial. Authors found that the DN group improved significantly compared to the control group after treatment and at follow-up [Dry needling (DN) is one of the physiotherapy interventions, which has been utilized in patients with LBP . In a clollow-up . A systeollow-up . A systeollow-up . Furtherollow-up . To dateThis pilot study used a single-group pretest-posttest clinical design. The study was conducted in the Physiotherapy Clinic of Tehran University of Medical Sciences (TUMS). The Ethical Committee of TUMS approved the study protocol (Code: IR.TUMS.FNM.REC.1397.056). Study objectives were explained to the patients, and written informed consent was obtained from them.Women staff and students of School of Rehabilitation, TUMS, were recruited for the study. Inclusion criteria were as follows: (1) having LBP for at least12 weeks, (2) reduction in the passive knee extension test of ≥25°, (3) severity of the current back pain between 3 and 7 on the VAS, and (4) giving consent to participate in the study. The exclusion criteria were as follows: (1) contraindications for DN, (2) the history of fracture in the lumbar or femoral regions, (3) inability to perform the assessments, and (4) acute recurrence of LBP.Patients were assessed regarding the eligibility criteria before they entered the study. The same orthopedic physician examined the patients for eligibility and nonspecific LBP diagnosis; however, a physiotherapist also reassessed the patients for eligibility at baseline and before delivering DN. Patients who fulfilled the eligibility criteria underwent one session of DN of the hamstring muscles.The characteristics of age, weight, height, BMI, and LBP duration were recorded. The assessor was an experienced physiotherapist who applied the outcome tests randomly. Another physiotherapist who was experienced using DN and blinded to the results of assessment treated the patients. The assessments were performed before DN (T0), immediately after DN (T1), and one week after the DN (T2). This study was conducted at the Physiotherapy Clinic of TUMS, Tehran, Iran.∗60 mm; DongBang AcuPrime Ltd., Korea). The patients were positioned in prone. DN was performed on three points on the hamstrings for both lower limbs, each point for one minute, using the fast in-fast out cone-shaped technique. As used previously [The physiotherapist delivered the deep DN using disposable sterilized needles , passive knee extension (PKE) test, finger-floor distance (FFD) test, and functional rating index (FRI) were the outcome measures to assess the severity of pain, flexibility of hamstring muscle, lumbopelvic mobility, and functional disability.We used the VAS to measure the severity of pain at rest. The patients were asked to determine the severity of pain on a 10 cm horizontal line from “0” (no pain) to “10” (most severe pain) .The hamstring tightness for both legs was randomly assessed using the PKE test. Patients were positioned in supine on a firm bed. The contralateral leg was fixed to the table in extension by a strap. The hip and knee of the tested leg was positioned in 90°-90° flexion. Then, the knee was passively extended to the maximal tolerable stretch point reported by the patient; the knee angle was measured at this point using a goniometer , 15. TheThe FFD test was used to assess lumbopelvic mobility. The patients were asked to stand without shoes or socks (bare feet) on the ground while keeping their legs close together. They were asked to bend forward as much as they could and to reach their fingers to the floor without flexing their knees. The distance between the tip of the right middle finger and the floor was measured as the FFD score using a standard tape. Higher distances were indicative of greater hamstring tightness and limited lumbopelvic mobility .We used the Persian version of the self-report FRI to assess disability. This questionnaire consists of 10 items, each item is rated on a Likert scale from “0” (no pain or disability) to “4” (worst possible pain or inability to function). The total score is the sum of all items' scores, ranging between “0” and “40” expressed in percentage disability of “0%” (no disability) and “100%” (severe disability). Persian FRI is a reliable  and valid  tool for assessing LBP-related disability .t-test was used to analyze the changes of FRI scores. Cohen's d was calculated to determine the magnitude of the DN effect defined as small <0.50, moderate 0.50–0.80, and large ≥0.80 [P ≤ 0.05 was interpreted as statistically significant.The data analysis was carried out using SPSS software for Windows 22.0 . We calculated the mean and standard deviation (SD) for continuous variables and number and percentage for categorical variables. The Kolmogorov–Smirnov (KS) test was employed to assess whether the variables were normally distributed. One-way repeated measure of analysis of variance (ANOVA) with time as within-subject factor measured at three time points was used. Bonferroni adjustments were applied for post hoc paired comparisons of testing time points. Mauchley's test was used to analyze the homogeneity of variances. The paired ge ≥0.80 . P ≤ 0.0Before we began the current pilot study, we conducted a power analysis for the future larger randomized, controlled trial. With ANOVA, repeated measure, between factors as the statistical test, effect size of 0.5, significance level of 0.05, power 0.80, two groups (DN and sham DN), and 3 measurements, a total sample size of 24 patients would provide adequate power to detect meaningful differences between groups.p=0.16) revealed significant decreases in the pain severity after DN  = 22.56, p < 0.001). Pairwise comparisons using Bonferroni showed significant reductions in pain severity at T1 (p=0.01) and T2 (p=0.001). The reduction in pain severity at T2 was significant compared to that at T1 (p=0.008).p > 0.05) revealed significant increases in both the right  = 7.58, p=0.004) and left  = 5.68, p=0.01) PKE after DN at T1 and T2 (p=1.0).Repeated measure ANOVA with sphericity assumption (1 and T2 . The incp=0.07) revealed significant improvement in FFD after DN  = 9.18, p=0.002). Pairwise comparisons using Bonferroni showed significant improvements in FFD at T1 (p=0.01) and T2 (p=0.04). The improvement in FFD remained the same at T2 compared to that at T1 (p=0.94).Repeated measure ANOVA with sphericity assumption .The FRI scores significantly improved at T2 one week after DN compared to that at T0 , muscle strength, and coordination , 22. MosThe effect size of DN in pain reduction immediately after treatment was moderate and large at seven days follow-up. In order to be clinically significant, a 20% change in VAS should be reported for individuals with chronic LBP , 25. In Hamstring muscle tightness has been demonstrated to be higher in patients with LBP than healthy adults , 27. HamFlexibility of the trunk is usually the goal of physiotherapy programs in patients with LBP. We used the FFD as a relevant outcome measure to assess total mobility of the spine and the lumbopelvic rhythm in our patients with chronic LBP. In the current study, small effect sizes were obtained for the FFD despite clinically relevant improvements of 29% immediately after DN and 48% at one-week follow-up. Again, greater improvement occurred at one-week follow-up confirming the time required for DN effects to be optimized . The posd = 0.72) was obtained, improvements were greater than MCIC of 10.63% reported for the Persian FRI in patients with chronic LBP [The FRI as a measure of function was improved 30% in this sample with chronic nonspecific LBP. Although a moderate effect size (onic LBP . This fiThe current pilot study was primarily conducted to provide information on the feasibility, treatment effect sizes on outcomes, and data for power determination to design the future randomized trial. The present pilot study provides preliminary evidence on efficacy on the pain, hamstring flexibility, and disability in patients with chronic LBP with hamstring tightness. However, our sample size estimation for two groups with sham DN as a control group shows a total sample size of 24 patients to be assigned equally for two groups. Hence, the sample size for this pilot study was small to draw definite conclusion on the efficacy of DN in chronic LBP patients with hamstring tightness. So, the future main rigorous study should be undertaken to eliminate the potential biases and to answer the research question justified by the positive outcomes found in this pilot study. Nevertheless, despite the small sample size of the present pilot study and the lack of a control group, its results support the DN intervention for alleviating pain and disability in patients with chronic LBP and hamstring tightness.The current study has limitations. First the sample size was small. Second, only women were included. A convenient group of students and office workers was included. Chronic low back pain is common even in young women individuals , especiaA single session of dry needling used in this study of patients with chronic LBP and hamstring tightness improved pain and function and increased hamstring flexibility. The usefulness of DN applied as a stand-alone therapy suggests a promising intervention in clinical practice for patients with chronic nonspecific LBP and hamstring tightness. The current study was a pilot single-group clinical trial without the sham control group that may make the dry needling appear more effective intervention. Further rigourous double-blinded randomized clinical investigations with long-term follow-up are warranted to confirm the findings.


Knee osteoarthritis is a common disease with pain as the most prevalent symptom. Previous cohort studies have shown genicular artery embolization to reduce pain symptoms in patients with mild to moderate knee osteoarthritis. Patients resistant to conservative therapy but not eligible yet for surgical treatment due to young age or comorbidities may profit from an effective and sustained pain reduction treatment. This study is a randomized sham-controlled trial to evaluate the efficacy of genicular artery embolization in patients with knee osteoarthritis.Fifty-eight patients with mild-to-moderate knee osteoarthritis will be recruited and randomly allocated to the treatment or control group in a 1:1 ratio. Participants in the treatment group will undergo genicular artery embolization. Patients in the control group will undergo sham treatment. Outcome measurements will be assessed at baseline and after 1, 4, 8, and 12 months with questionnaires, pressure pain threshold testing, and MR imaging. The MR imaging protocol is designed to (semi)quantitatively assess osteoarthritis in the knee joint. The primary outcome is the change from baseline of the Knee injury and Osteoarthritis Outcome Score (KOOS) pain subscale after 4 months. Secondary outcomes include change in osteoarthritis-related questionnaires, pressure pain threshold, and OA-related MRI features, particularly synovitis and bone marrow lesions.This trial will determine the efficacy of genicular artery embolization compared to a sham treatment. This is of importance to assess before proceeding to larger-scale efficiency studies and, ultimately, implementing this treatment into day to day clinical practice.ClinicalTrials.gov NCT03884049. Registered on 21 March 2019 Knee osteoarthritis (OA) is the most common joint disorder and a leading cause of morbidity worldwide, ranking highly on the list of contributors to disability . OA alsoRecent clinical studies have shown an effective pain reduction following genicular artery embolization treatment (GAE), during which periarticular angiogenesis is embolized –9. The oOkuno et al. used GAE to reduce angiogenesis in 95 patients with knee OA . They foTherefore, the main objective is to assess whether genicular artery embolization for patients with symptomatic knee OA results in significant pain reduction after 4 months compared to sham treatment. A secondary aim is to obtain further insight into the role of angiogenesis in knee OA pathophysiology using advanced magnetic resonance imaging (MRI). A tertiary aim is to investigate whether pain sensitization is influenced by GAE using pressure point threshold testing.This study is a single-center, double blind randomized sham controlled trial. It will be performed at the Erasmus MC, University Medical Center Rotterdam, the Netherlands.This is a study with multi-center recruitment from orthopedic outpatient clinics of the Erasmus MC and hospitals in the region. Written informed consent will be obtained by a clinical researcher prior to enrollment in the trial. The study population consists of patients age ≥ 18 years with symptomatic, mild-to-moderate radiographic knee OA (Kellgren and Lawrence (KL) grade 1–3)  resistanAge ≥ 18 yearsKnee pain for a duration of ≥ 6 monthsKnee pain  on at least half of the days in the preceding month at time of inclusionInsufficient response to conservative treatment for at least 6 monthsRadiographic knee osteoarthritis (KL grade 1–3)Contra-indications for MRI Contra-indications for angiography Previous surgical treatment for knee osteoarthritis , excluding knee arthroscopyMusculoskeletal co-morbidity  potentially masking the effect of GAE2)Renal insufficiency, determined with a blood sample test . The clinical researcher, blinded for randomization, will conduct the MRI scans, evaluate patients during follow-up, and will enter the patient data into an online database. The interventional radiologist who will perform the procedure will be automatically informed about the randomization result by email. The allocation will only be sent to the interventional radiologist and a third party within the department who safeguards the randomization code. All others, including the clinical researcher, treating orthopedic surgeon, and patients, will be blinded tot group allocation.Patients will be randomized 1:1 using a random block size strategy with block sizes of 4 and 6. Randomization is performed using an online randomization tool  catheter will be inserted into the common femoral artery. Initial digital subtraction angiography targeted on the vessels around the knee will be performed using Iodixanol 320 mg I/ml . Culprit vessels will be catheterized using a 1.8 Fr microcatheter with micro guidewire and embolized using Embozene Microspheres 75 μm or 100 μm  dissolved in 20 ml of Visipaque 320 until stasis of flow is achieved. When no evident culprit vessel is identified, the distal branch of the genicular artery corresponding with the most painful location is embolized. After finishing the embolization procedure, the sheath will be removed, and the puncture location is manually compressed for at least 10 min after which patient is immobilized for at least 3 h, followed by discharge. The procedure time varies between 1 and 2 h.In the sham group, the patient setup is exactly the same as in the treatment group. After anesthesia, a small incision will be made mimicking the incision in the GAE group. The interventional radiologist will pretend to insert a catheter in the femoral artery and perform angiography and embolization. The common femoral artery will not be punctured. The C-arm of the angiography system and the table will be moved during the sham procedure mimicking the actual procedure; however, no images are actually made, so there is no unnecessary radiation exposure. The sham procedure will take approximately as long as the actual intervention.After both procedures, the site of incision will be manually compressed for 10 min after which the patient is immobilized for at least 3 h followed by discharge. Before discharge, blinding for group allocation will be tested in all patients by asking in what group they think they were allocated to. They have 3 options: “intervention group,” “sham group,” and “I don’t know.” This timing has been chosen since testing later on in the trial could potentially be influenced by efficacy and side effects of the treatment .Data on the usage of co-interventions will be collected at every follow-up visit through an interview. Patients will be encouraged not to start any new conservative treatments they were not receiving at baseline. Besides no new pharmacological treatment, this also includes no new corticosteroid injections, physiotherapy, or the usage of a brace. They can, however, increase or decrease any pharmacological treatment they were receiving based on their complaints, continue an already ongoing physiotherapy treatment, or keep wearing a brace if they were using one. This information will be recorded.Outcome measurements will be recorded at baseline and 1, 4, 8, and 12 months after the procedure. The primary outcome is change of the knee injury and osteoarthritis outcome score (KOOS ) pain suChanges on MRI will be compared between baseline and after 1 and 4 months. All clinical trial study activities are summarized in Table For the main outcome, the KOOS questionnaire is used . This qu2 . Measurements will be performed with the patient’s knee in 30° of flexion. The sites of measurements are at the medial and lateral joint space 2 cm medial and lateral to the inferior edge of patella, 2 cm above the superior border of the patella, and a peripheral site at the center of the brachioradialis muscle at the contralateral side from the treated knee. Pressure of gradually increasing intensity (10 N·s−1) is applied. The patient is instructed to say “stop” at the moment the sensation switches from pressure to painful. These measurements are repeated three times and are averaged to determine the pressure pain threshold. The sites are marked such that repeat measurements will be at the same location. Before measurements start, a test measurement will be done at a site not used for actual measurements for patients to get familiar with the measurements. Measurements are repeated 3 times and the average will be considered the pressure pain threshold. This method to determine the PPT has a high reliability with intra class correlation coefficients of 0.95–0.97 [2 was implemented to prevent tissue damage.At baseline and each follow-up visit, pressure pain threshold testing (PPT) will be performed using an algometer with a tip of 1cm.95–0.97 . A cutofAll patients will undergo MRI at baseline and at 1 and 4 months after treatment. Images will be acquired using a 3.0-T MR system with 70 cm bore  equipped with an 18-channel dedicated knee coil . The MRI protocol consists of Double Echo Steady State (DESS), 3D PD (proton density) weighted fast spin echo, axial and sagittal T2 fat saturated (FS), sagittal MAGnetic resonance Image Compilation (MAGiC) synthetic imaging, dynamic contrast enhanced (DCE) MRI using DIfferential Subsampling with Cartesian Ordering (DISCO), and post contrast T1 weSPGR pulse sequences. During the DCE-MRI, 0.1 ml/kg gadovist  followed by 15 ml of saline will be administered at an injection speed of 1.0 ml/s using a contrast injector . This protocol was designed to assess the knee tissues semi quantitatively using the MRI Osteoarthritis Knee Score index (MOAKS ) and quaAdverse events (AE) are defined as any undesirable experience occurring to a subject during the study period, whether or not considered related to the intervention. One day after the procedure, the patients will be contacted and actively screened for the occurrence of any adverse events. Patients will be asked to report any changes in their health status. At every follow-up visit, patients will be actively screened for the occurrence of any AE.Possible adverse events related to GAE are as follows: transient discoloration in the region of embolization due to non-target embolization or nerve damage due to non-target embolization. Only patients in the intervention group are subjected to these risks. All patients will receive local anesthesia and a small incision in the groin and are therefore subject to the risk of access-site hematoma and access-site infection. All patients undergo MRI with contrast agent injection and are therefore at risk for an allergic reaction to gadolinium.After including 10 patients, a data and safety monitoring board (DSMB) will perform a safety analysis. The DSMB consists of an interventional radiologist, an orthopedic surgeon, and a biostatistician. The aim of this committee is to protect the interests of patients enrolled in this study and to evaluate the safety of the investigational intervention used in this trial. (S)AE’s and pain scores will be used to test if the intervention is deemed safe enough to continue the trial. The local ethical board will receive a report and will decide if the trial can continue. The members of this DSMB are independent of the trial. They were not involved in the creation of the protocol or have any competing interest.Additionally, the trial conduct will be audited every 6 months by an independent auditor from the Department of Radiology & Nuclear Medicine of Erasmus MC.n = 24 per study arm) are required to detect an increase (higher scores indicate less pain) in primary outcome measure of 8 points in the control group (placebo effect) compared to 21 points in the intervention group. The targeted sample size will be 58 to account for approximately 20% of patients lost to follow-up. We also expect a more homogeneous study population since all included subjects have an NRS pain score ≥ 4 and ≤ 8. With this sample size, and in case of lower variation in pain scores than SD of 16, we expect we could also detect smaller effect sizes between 0.5 (moderate effect) and 0.8.Calculations are partly based on the previous observational studies by Okuno et al. , 7. Despwww.OpenClinica.com.), an online password protected electronic data capture system. Data will be collected anonymously. A source document review of randomly selected subjects will take place to ensure correct entering of data. All paper files will be preserved for at least 15 years.All outcomes will be entered into OpenClinica Community software  will be used to enable inclusion of all available measurements in the regression models even if they are correlated. It also allows us to adjust for unequal distribution of prognostic variables over the two groups, which easily can occur in smaller randomized clinical trials. Radiographic severity, pain pressure threshold, and degree of sensitized pain according to painDetect will all be tested for equal distribution and, if more than 10% different, we will test if this variable changes the estimate with more than 10%. If this is the case, the variable will be included in the adjusted analysis. The adjusted analysis will be the primary analysis, but we will also present the unadjusted analysis. If some of the patients do not receive the treatment as allocated, we will also perform a per protocol analysis where the patients that did not comply with the allocated treatment will be excluded. Repeated measurement regression analysis will also be used for all continuous secondary outcomes: KOOS subscales, VAS, ICOAP, painDETECT, EQ-5D-5L, and PPT scores.GAE is a novel intervention for patients with symptomatic, mild-to-moderate knee OA , 7. InitIn our initial protocol, we planned for the sham group to undergo angiography of the genicular vessels without embolization in order to visualize and compare the angiogenesis in both groups. However, after consulting with the local ethical committee, this was deemed too invasive as a sham intervention for patients who already had knee complaints and was not necessary to achieve the primary objective. Therefore, we changed the sham treatment to be an incision in the groin without a catheter entering the femoral artery. This less invasive form of a sham procedure is a challenge with regard to blinding. Patients must be under the impression that a catheter is actually entering the arteries and that the interventional radiologist is performing the procedure. Using noise-canceling headphones so patients cannot hear their surroundings, using the C-arm to mimic angiography, and giving patients in the sham group the same post procedural care as the intervention group are examples of how we maintain adequate blinding. The upside of changing the sham procedure to this less invasive method is that patients will not be exposed to any unnecessary additional risk associated with angiography. To assess whether we succeeded to keep the intervention blinded for the patient, we will ask them for their own perception of group allocation after the treatment.Several research groups are currently evaluating the outcome of GAE. Recently, results of non-randomized pilot studies have been published showing promising results; however, the authors also state the importance of testing GAE in a randomized controlled trial , 9. BecaWe are aware of one published protocol describing a similar trial . We beliThe current protocol version is 1.6, dated at 31 July 2020 and is approved by the local research ethics committee. As of 26 April 2020, we have included 40 patients and aim to finish inclusion in the first half of 2021. After 10 inclusions, there was a safety interim analysis by an independent data safety monitoring board. They compared adverse events occurring in both groups to confirm no unacceptable (serious) adverse events occurred in either group. The DSMB concluded the trial was safe to continue.Furthermore, Bagla et al. noticed a reduced amount of neurogenic complications when they used 100 μm embolization particles compared to 75 μm . Therefo