In this study, the characteristics and distribution of the organic phosphorus (Po) fractions in the surface sediments of seven inflow rivers around Hongze Lake in China were analyzed with a soil Po fraction method, as used by Ivanoff. The relationships between the Po fractions and physiochemical features of sediments were also discussed. The results showed that, the sediments of the rivers had been moderately pollution with certain ecological risk effects except the Waste Yellow River. The relative contribution order of the Po fractions in the sediments was residual Po > HCl-Po > fulvic acid-Po > humic acid-Po > labile organic phosphorus (LOP). Moderately labile organic phosphorus (MLOP) was the main part of the Po forms in the whole sediments. The risk of phosphorus released from river sediments was the highest in the western region, followed by the southwestern region, and finally the northwestern region. There were significant correlations between Po forms and total phosphorus (TP), inorganic phosphorus (Pi), and Po. Non labile organic phosphorus (NLOP) had the strongest correlation with TP. The distribution of Po forms in each region was different due to the impact of human activities, industrial and agricultural production and the land types; the heaver polluted sediments with higher Po fractions. It is suggested that most of the sediments of the inflow rivers in the regions have certain ecological risk effects and P of them have an important contributions on the eutrophication of Hongze Lake. Po forms can provide a reliable theoretical basis for dealing with the change of water quality and should be paid more attention in the lake eutrophication investigation. There was reciprocal transformation between different Po forms, especially non-bioavailable fraction can change into bio-available ones. The results can provide a basis for the earth cycle of phosphorus and a new perspective of eutrophication control of shallow lakes. Phosphorus (P) is an essential nutrient for aquatic organisms and is a limiting nutrient for primary production in lake ecosystems ,2,3, so For these reasons, in recent years, sequential extraction schemes have been developed based on the assumption that chemical extractants selectively dissolve discrete groups of Po . These m2, and the results showed that 85.4% of the lakes have eutrophication issues, and almost half of them (>40%) are hyper-eutrophic lakes [In the last twenty years, the booming economy of China, with fast development of agricultural and industrial activities, has led to serious eutrophication of the hydroecological sytem ,28. The ic lakes . Wu et aic lakes . Hongze ic lakes . Expertsic lakes . In viewic lakes ,34,35. TThe objectives of the present study were to: (1) investigate physiochemical features in the surface sediments of inflow rivers around Lake Hongze; (2) investigate the characteristics and distribution of Po fractions and the bioavailability in the surface sediments of the study areas according to the land use type sediments, and (3) analyze the relationships between Po and physicochemical nature of the sediments.We take the northwest to southwest of the Hongze Lake Basin as the research area. Seven tributaries or main stream sediments were selected in the basin as the research objects. The distribution of sampling points is shown in 2, a maximum water depth of 4.37m, an average water depth of 1.77 m, a water storage capacity of 27.9 × 108 m3 and a shoreline of 354 km. The lake area has monsoon climate characteristics, which is regulated by the Hongze Lake water body, with four distinct seasons. The annual average precipitation is 925.5 mm, and the rainy season is mainly from June to September [3, and the water exchange rate reaches 11 times per year. As a hub connecting the middle and lower reaches of the Huaihe River, Hongze Lake and Huaishuxin River connect the Huaihe River system with the Yi, Shu, and Sishui systems. It is necessary to not only regulate and control the flood in the upper and middle reaches, but also to store part of the incoming water, which irrigates a large area of farmland in Northern Jiangsu, and protects the safety of more than 20 million people and 2 million square hectares farmland in the Lixia River area in Northern Jiangsu. The east line of the South to North Water Transfer Project in China will also transfer 400 m3/s of water northward through Hongze Lake. However, with the aggregation of human activities, Hongze Lake has become the main receiving water body of industrial wastewater and domestic sewage in the upper and middle reaches of the Huaihe River, and water pollution has reduced the ecological service function of Hongze Lake [Hongze Lake, located in the northwest of Jiangsu Province , is a shallow water lake with a water area of 1597 kmeptember ,37. Thergze Lake ,39.2Cr2O7/H2SO4 according to Walkey–Black method [2SO4 digestion method [2SO4 and 0.5 g of K2S2O8 and autoclave digestion during 30 min at 121 °C, total phosphorus (TP) in the extract was determined [In this study, 65 sampling points were set up using a grasp sampler in June 2015 and 2016, with a sampling depth of 0–10 cm. the sampling points numbered C1 toF11 are located on the Waste Yellow River, X1to X11 are on the Xuhong River, A1 to A10 are on the An River, S1 to S8 are on the Sui River, B1 to B9 are on the Bian River, XH1 toXH9 are on the Huihongxin River, and H1 to H7 are on the Huaihe River. Each sediment sample (a composite of samples from five nearby sampling sites) was immediately put into air-sealed plastic bags and storage in a heat preservation box with ice (about 4 °C). Then, the collected sediments were freeze-dried, crushed, passed through standard 100-mesh sieves and stored at 4 °C in the dark until further analysis. Sediment pH was determined on sediments suspended in deionized water at a ratio of 1:2.5 . Total Fk method . Total nn method . After atermined . Inorgantermined .3 at pH 0.5. The extracted Po was mainly called the loosely adsorbed Po on the sediment colloids. The moderately labile Po was extracted with 1.0M HCl followed by 0.5 M NaOH. The NaOH extract was acidified to pH 0.2 with 37% HCl, and the non-labile component (humic acid-Po) was isolated from the appropriate fraction (fumic acid-Po). Finally, by buffering the residue extracted by NaOH, the non-labile segmentation is determined by high resistance H2SO4 dissolved to 1 M at 550 °C for 1 h. Each extraction step is performed at room temperature in an orbital shaker running at 4500 r/min. TP in all extracts was calculated with an aliquot that was digested with K2S2O8 and H2SO4. Po in the samples was calculated by the difference between TP and Pi.A sequential extraction method used to obtain different forms of Po based on the Ivanoff et al. scheme , presentThe whole samples were analyzed in triplicate and the results are expressed as the average values. The distribution of sampling points was drawn by ArcGIS . The descriptive statistical analyses were conducted using the SPSS ver. 23.0 statistical software package . Charts were plotted using the Origin 9.0 software .The general characteristics and physiochemical features of lake sediments are shown in p < 0.01, n = 65). Carbonate calcium is greatly affected by environmental pH, which easily forms precipitation in alkaline environments and is easy to dissolve and release in acid environments.The average value of the four metal elements in the study area was Al > Ca > Fe > Mn. The average value of Ca ranged from 3.38% to 6.03%, with the order Bian River > Sui River > Huaihongxin River > Huaihe River > An river > Xuhong River > Waste Yellow River. The concentrations of Ca in Hongze Lake basin were higher than other basins in the middle of China, such as the Tiaoxi basin ,47. This−1 to 1130.62 mg·kg−1; TP ranged from 488.90 mg·kg−1 to 960.22 mg·kg−1. OM, TN, and TP showed a great spatial difference. However, the sequence of OM, TN, and TP was the same.TN and TP also had a positive correlation with OM . Concentrations of OM, TN, and TP in the sediments were consistent with the trophic status of those studied lakes. In sediments of the seven rivers, the pollution was more and more serious from northwest to west and from southwest to west. Bian River was the most polluted, then the Sui River. This was because the rivers of the west were far away from the cities. Along the rivers, aquaculture and agriculture are relatively developed. Domestic sewage and industrial waste water are not centrally disposed.OM is one of the most important colloids in sediments, mainly derived from many kinds of residual of authigenic alga and bacteria. It can absorb, distribute, and complex with heavy metals and organic pollutants, which is an important indicator to reflect the organic nutrition level of sediment ,52. The −1 and TN exceeds 600 mg·kg−1 in the sediment, it can cause the lowest level of ecotoxicity effect [−1 in the sediment, there had been no pollution; when 500 mg kg−1 < TP < 1000 mg·kg−1 in the sediment, there had been moderate pollution, so in addition to the Waste Yellow River, the sediments of rivers from the northwest to the southwest of Hongze Lake Basin had a certain ecological risk effect and had been moderate pollution with certain ecological risk effects. For the whole region, the nitrogen/ phosphorus (N/P) of the sediments ranged from 1.17 to 1.72, far less than the Redfield ratio (C: N: P = 106:16:1). On the one hand, this reflects that the phosphorus in the sediments is mainly imported from land. Due to the different geological structure, landform, land use type, vegetation damage, and surface runoff erosion, a large number of phosphorus-containing substances are brought in by land-based sources of rivers entering the lake. On the other hand, this reflects that the biochemical action of the sediment the sediment–water interface in shallow lakes is intense, and the dissolved oxygen with low concentration causes nitrogen (N) to be lost due to mineralization and degradation, while P is enriched in the sediments [Exogenous input is the main factor affecting TP and TN, and the concentrations were higher in the heavily polluted areas. According to the Sediment Quality Guidelines issued by the Ministry of Environment and Energy of Ontario (Canada), when the concentration levels of TP exceeds 600 mg·kgy effect . With thy effect , when TPediments ,56.−1 to 731.34 mg·kg−1, accounting for 65.81–76.15% of TP. Po ranged from 167.16mg·kg-1 to 228.88 mg·kg−1. Relative contributions were 34.19%, 33.30%, and 32.61% for Waste Yellow River, Xuhong River, and An River, respectively. The population mean was 33.84% for the northwestern region. It was the highest among the southwestern region, named Huaihongxin River (27.85%) and Huaihe River (32.17%) with the population mean at 30.18% and the western region, including Sui River (24.82%) and Bian River (23.83%) with the lowest population mean at 24.58%. From Except for point B1, the concentration of TP at the entrance of each river to the lake was the highest value of the river. One reason was that the dynamic condition of the lake inlet was poor, and the sediments were easy to accumulate, which lead to the increase of the concentration of TP. The higher concentrations of TP in the sediments of the lake inlet will affect the concentrations of TP in the water of Hongze Lake, which will finally increase the risk of eutrophication of Hongze Lake. The concentration of TP in the sediment of B1 was lower, it may because that there was a large amount of land used for growing grass. Grassland can reduce the concentration of nutrients in sediment . The incPo is mainly deposited in the processes of river input, human emission, metabolism of aquatic animals, and plants. Its content will directly affect the availability level of soluble P required by primary productivity . Po can −1 to13.55 mg·kg−1, and the average was 11.81 mg·kg−1, the only relative contribution was 5.66% to6.52%, and the average only 5.94% of Po, less than 7% in the soil [LOP is the most active component of Po, which has high biological efficiency. However, this part of phosphorus was also the least in the form of Po. Its percentage content was the key factors for the degradation of Po mineralization to Pi . The LOPthe soil . The seqObviously, the higher the pollution degree, the lower the contributions of LOP. The difference of contribution of LOP indicated that the contribution of polluted sediment released to overlying water through mineralization is higher than that of less polluted sediment, which has a greater impact on eutrophication of rivers .−1 to 105.20 mg·kg−1, with the relative contribution of Po at 43.93% to 54.47%. MLOP was the same as LOP, where the concentration was higher in heavily polluted sediments, and the percentage decreased. HCl–Po was the main part of the MLOP, the chemical components are mainly phosphate ester, phospholipid, nucleic acid, phosphoprotein, and phosphosaccharide, which are easily, decomposed bio-macromolecules with poor stability. Under certain conditions, they can be hydrolyzed or mineralized, decomposed into soluble small molecule organic phosphorus or soluble phosphate, and have potential biological effectiveness through migration and diffusion of pore water [−1 to 79.78 mg·kg−1, accounting for 22.45–33.32% of Po. Huang Qinghui et al. found that the release of acid extractable organic phosphorus from sediments may be one of the important processes leading to lake eutrophication in the study of Lake Taihu, Chaohu, and Longgan in the east of China. Hua Liping et al. also put forward the same view in the study of Lake Baiyangdian in the north [MLOP included HCl–Po and fulvic acid-Po. It is the most active component in the Po, which has a certain biological effectiveness. On the whole, the concentration of MLOP ranged from 87.51 mg·kgre water ,65. In the north . In addihe north . HCl–Po/he north . Fulvic NLOP was the least active component of Po, with low bioavailability. It consisted of humic acid–Po and residual Po with relative contributions of 7.71–13.41% and 25.61–42.70% of Po. The concentration and the percentage of NLOP increased with the increase of pollution degree, it was different from LOP and MLOP. The NLOP relative contribution of Bian River was over 50% to Po.In this study, the relative contribution of bio-available organic phosphorus (LOP + MLOP)  in riverThe relationships between Po fractions and physiochemical features are shown in p < 0.01, n = 65). It might be that MLOP mostly existed in the form of calcium. NLOP had a significant correlation with Fe . This showed that NLOP was easily an effective carrier of Fe [p < 0.01, n = 65), than with the Pi . This proved the viewpoint of Zhang [There was a significant correlation between Ca and MLOP  The sediments of the whole rivers had been moderately pollution with certain ecological risk effects, except the Waste Yellow River. Except for point B1, the concentration of TP at the entrance of each river to the lake was the highest value of the river. It is suggested the higher concentrations of TP in the sediments of the lake inlet will finally affect the concentration of TP of Hongze Lake, which will lead to a risk of eutrophication of Hongze Lake. (2) The characteristics and distribution of Po fractions were different in rivers with different pollution levels, suggesting that Po fractions were indicators of eutrophication and should be paid more attention in an- lake eutrophication investigation. (3) Non labile organic phosphorus (NLOP) had the strongest correlation with TP. It may also suggest that NLOP can transfer into a potential source of available P for aquatic phytoplankton and bacteria, although it was considered as the non-bioavailable fraction.In the process of eutrophication treatments of shallow lakes that rivers flow into, more solicitude should be shown for non-point source pollution and internal phosphorus of the lake. However, the contractions of Po fractions and the transformation of different forms of Po in the sediments of the upstream rivers can’t be neglected, which should be paid more attention. What’s more the transformations between the Po fractions are complex. We can use 31P-NMR to research the mechanism of the transformation of internal Po in the sediments in the further investigation to help controlling the eutrophication. Additionally, the concentrations of phosphorus forms in the sediment of the inflow rivers have a certain contribution to the eutrophication of the shallow water lake, but the specific contribution degree needs to be further fitted with the water quality model.


C‐statistic of 0.81). Linear predictors for donor mortality served as summary of donor prognosis in recipient models. Age, sex, year of transplantation, dialysis vintage, primary renal disease, cerebrovascular disease, peripheral vascular disease and HLA mismatch were selected to predict recipient mortality (C‐statistic of 0.77). Age, dialysis vintage, linear predictor of donor mortality, HLA mismatch, peripheral vascular disease and heart disease were selected to predict graft loss (C‐statistic of 0.66). Our prediction models inform decision‐making at the time of transplant counselling and are implemented as online calculators.Although separate prediction models for donors and recipients were previously published, we identified a need to predict outcomes of donor/recipient simultaneously, as they are clearly not independent of each other. We used characteristics from transplantations performed at the Oslo University Hospital from 1854 live donors and from 837 recipients of a live donor kidney transplant to derive Cox models for predicting donor mortality up to 20 years, and recipient death, and graft loss up to 10 years. The models were developed using the multivariable fractional polynomials algorithm optimizing Akaike’s information criterion, and optimism‐corrected performance was assessed. Age, year of donation, smoking status, cholesterol and creatinine were selected to predict donor mortality ( Kidney transplantation is a cost‐effective treatment option for eligible end stage renal disease patients, because it is associated with improved survival, better quality of life and less costs compared to maintenance dialysis The decision‐making process for a living donor kidney transplantation, however, is complex and requires a careful assessment of the risks and benefits for both, the donor and the recipient. In particular, as the donor does not derive any medical benefit from a kidney donation, it is important to achieve a balance between preventing harm to the donor and improving the recipient’s prognosis. This risk‐benefit assessment rarely is straightforward because it largely depends—besides established clinical determinates of suitability to donate or receive a kidney—on how donor and recipient weigh their individual risks against the potential benefits; for example, a parent kidney donor is likely to accept a higher risk for oneself if the child’s prognosis is improved, even at a lower chance Although separate risk prediction models for donors and recipients were published in the past, we were unable to find a risk calculator to predict outcomes of donor/recipient pairs which clearly are not independent of each other. Two models were developed to predict recipient death at five years after transplantation, constituting a rather limited time horizon given the good long‐term prognosis expected from a living donor kidney transplant nowadays Thus, we identified a need for linked risk prediction models that predict relevant hard long‐term outcomes for the donor and recipient simultaneously to advance the evidence base for transplant counselling. The primary aim of this study therefore was to develop the donor and recipient linked iPREDICTLIVING tool to predict donor, recipient and graft survival following kidney donation or living donor kidney transplantation simultaneously taking a potential transmission of the donor’s risk profile to the recipient’s risk into account.This manuscript is written following recommendations of the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement for prediction studies A retrospective cohort of first single‐organ living donor kidney transplant recipients and living kidney donors from the Oslo University Hospital, Oslo, Norway, were used to develop the risk prediction models. In Norway, a single centre, the aforementioned Oslo University Hospital, performs all kidney transplantations and 30–40% of all kidney transplants come from a living donor. Eligibility for a living donor transplant is determined according to international guidelines All donors recorded in the database who donated a kidney between 1 January 1980 and 31 December 2007 were included in this analysis. As collection of recipient comorbidities commenced on 1 January 1995, all consecutive adult  recipients of a living donor kidney between 1 January 1995 until 31 December 2007 were included in this analysis. Information on the degree of sensitization to donor specific HLA epitopes of the recipient is not available from this database, as it was not performed routinely before 2010 Outcomes of interest were donor death, recipient death and graft loss. Donor and recipient death were defined as all‐cause mortality, including death with a functioning graft for recipients. Donor and recipient survival time was defined as the time from kidney donation or transplantation until death, end of follow‐up, or 10 March 2015, whichever occurred first. Graft survival time was defined as the time from transplantation until either permanent return to dialysis treatment or second transplantation, counting death and end of follow‐up as censored observations.We used donor and recipient characteristics available at the time of transplant counselling as candidate predictors to develop the risk prediction models.We developed three prediction models within the iPREDICTLIVING tool to predict: (i) donor death following living kidney donation , (ii) recipient death following living donor kidney transplantation  and (iii) graft loss following living donor kidney transplantation (graft loss model).C‐statistic of the respective model improved by adding pretransplant dialysis duration.Candidate predictors were determined based on clinical judgment and existing background knowledge on relevance of risk factors for donor and recipient outcomes. Candidate predictors for the donor death model were the following donor characteristics: age, body mass index, sex, smoking status, serum creatinine, fasting glucose, fasting total cholesterol, systolic and diastolic blood pressure, first degree relationship , any genetic relationship with the recipient and calendar year of donation. Candidate predictors for both recipients models were primary renal disease, presence of panel reactive antibodies, sum of HLA mismatch in class II (DR), sum of HLA mismatch in class I , diabetes mellitus, heart disease, cerebrovascular disease, peripheral artery disease, recipient sex, recipient age, calendar year of transplantation, renal replacement therapy modality , and donor prognosis. As our aim was to develop linked risk prediction models that account for a potential transmission of the donor’s risk profile to the recipient’s risk, we calculated the linear predictor for each donor for all included corresponding recipients using our donor mortality model. This individual linear predictor of donor mortality was then used as a metric candidate predictor for both recipient models. In order to keep the model parsimonious and as simple as possible for bedside use, we further decided a priori to include the duration of pretransplant dialysis treatment in the prediction model only if one of the three dummy variables for renal replacement therapy modality were selected into that model and if the Continuous variables are expressed by mean and standard deviation, categorical variables are presented by frequencies and percentages. Data availability was very good with recipient characteristics being completely available in the database for all patients. Missing donor variables were replaced by multiple imputation with chained equations P‐value threshold of 0.157, corresponding to a selection criterion according to the Akaike’s information criterion, and to allow possible nonlinear associations of donor age, and donor body mass index with donor mortality as well as recipient age with recipient mortality and graft loss P‐value of <0.01 for HLA mismatch using ordinal coding for increasing sum of class I and II antibodies separately. Biologically plausible interactions of selected main effects were tested as recommended by Royston and Sauerbrei using forward selection with a P‐value of 0.01 for all two‐way interactions between age and sex with all other selected predictors Multivariable Cox regression models were applied to develop the prediction models. Predictors were selected using the multivariable fractional polynomial algorithm at a C‐statistic) for 10‐year risk, and (iii) calibration, the agreement between observed and predicted risks, using visual inspection of calibration plots for 10‐year risk, and additionally 20‐year risk for donor death C‐statistic was calculated according to Steyerberg We used 1000 bootstrap resamples for internal validation to calculate optimism‐corrected performance measures and to estimate global shrinkage r software (R version 3.3.1) Analyses were done with We identified 1854 donors and 837 recipients with a median follow‐up of 14.6 years for donors and 13.1 for recipients  was 0.99, and 20‐year baseline survival was 0.95. The full prediction model with individual coefficients for all predictors is listed in Table 81 Table . The calC‐statistic was 0.77, and explained variation was 25.4%  is the official guidance issuing body of the European Renal Association—European Dialysis and Transplant Association (ERA‐EDTA). Dr. R. Oberbauer was supported by the Vienna Science and Technology Fund (WWTF# LS16‐019) and the Austrian Science Fund (grant #P25726). The study received no direct funds.MH: developed the study design, performed the study and wrote the manuscript. CW: performed the computations and wrote the manuscript. GM and HH: collected the data. DD and GH: verified the analytical methods. RO: perceived the original idea. GH and RO: supervised the study. All authors discussed the results, reviewed the manuscript, approved its final version and contributed important intellectual content.The authors of this manuscript have no conflict of interests related to this manuscript to disclose.


Grafting split-thickness (STSGs) and full-thickness skin grafts (FTSGs) are common techniques to replace missing skin and to restore the skin barrier in burn, trauma and remaining skin defects after tumor resections. The defect coverage with skin grafts offer many advantages, but also disadvantages such as donor site morbidity like possible sensory disturbances, scarring, risk of infection, contour changes and pigment disorders. We aimed to assess the preferred distribution of donor site for STSGs and FTSGs in patient’s skin grafting for plastic-surgical defect coverage.Patients and their accompany persons referred to the Department of Plastic Surgery were interviewed for defect coverage with STSGs or FTSGs, the preference in donor site was investigated and the detailed advantages and disadvantages were clarified. . Among all participants, 79 split-skin graft preferences were specified, while 32% favored the scalp as a donor site, as well as 29% the frontal part of the left thigh and 10% the frontal part of the right thigh. We evaluated 85 participants  with a median age of 42 years (mean=46 years). The definition of the donor site (n=188 markings) was mainly based on the physicians recommendation (32.98%), mobility (23.40%), aesthetic results (22.34%) and pain (21.28%). Feared complications (n=152) were mainly wound healing disorders (32.24%), circulation disorders (28.29%), scars (20.39%) and bleeding risks (19.08%)There were preferred anatomical donor sites for skin grafting. Nevertheless, in conscious patients, the donor site has to be selected in a consent talk and joint approval, preoperatively. The options of taking STSGs from the occipital region with all its advantages should be discussed intensively as it is an attractive graft donor site. Skin grafts can generally be divided into autografts, homograft and xenograft. Skin is a highly immunoreactive tissue and only autografts will heal in the transplanted area.4Autologous skin grafts, like split- or full-thickness skin grafts, in Meek and Mesh techniques are common techniques to reconstruct the skin and to restore the skin barrier in acute or chronic wounds.5 Already 3000 years ago, split-thickness skin grafts (STSG) were used in India for tissue reconstruction after punishments with tissue damage.6 In Europe mainly Gaspare Tagliacozzi of Bologna (1546–1599) developed the technique and published his work “De Curtorum Chirurgia per Insitionem (Surgery of the Mutilated by Grafting)” in 1597. In course of modern surgery, it was revived about 1817 in Germany for reconstruction of nasal defects.7The benchmark is to achieve complete wound healing in a very short time with minimal graft donor site morbidity. By using autologous skin grafts, an effective option to cover skin defects exists. In addition, skin grafts also seem to have a local regenerative effect.8-10 By transplantation of STSGs, a rapid defect healing and fast donor site healing were desired. Even if there are no studies comparing all possible donor sites regarding complications and skin take rate in a randomized controlled trial, the positive features of occipital donor sites were previously demonstrated.10Also in Switzerland Jacques-Louis Reverdin (1842–1929) developed his approach for skin grafting by using skin pieces of small, full-thickness skin grafts (FTSG). Regular donor sites were the lateral thigh and buttocks. Also in children, occipital donor sites are a common graft donor site for STSGs and were demonstrated with good outcomes regarding donor site complications and graft healing.11 Also based on frequent hair follicles as well as more adnexal structures, a high concentration of epidermal stem cells are available for regeneration in the donor.12,13 Regarding occipital donor site, good results were illustrated regarding graft take and healing rates. However, skin grafts are commonly taken from the thigh, even if good results were demonstrated for occipital donor sites.14In terms of complications like bleeding, pruritus and scarring, occipital donor site may have advantages compared to a femoral donor site.14 This graft donor site is mostly established in children and burn patients, but should also be offered to further patient collectives.10,15 The use of STSG and FTSG can be considered in burn patients, in reconstructive surgery, and in hand surgery but also in the therapy of chronic wounds.16In addition, prospective studies showed advantages of occipital donor site compared to the thigh. Particularly, it is a significant better reepithelization, better cosmetic outcome, better results on Vancouver Scar Scale and less pain.16 Investigations showed that the use of NPWT can enhance the graft take, reduce complications like seroma and hematoma too, but also enhance the quality of healing.17,18 The use of STSG in chronic diabetic wounds also showed an enhanced healing process in comparison to conservative therapy with paraffin gauze and iodine dressing.19Additionally the use of STSG can be combined with negative pressure wound therapy (NPWT) as an additional preparation of the wound bed before grafting, but also to enhance the healing process of the STSG postoperatively.According to experiences mainly the consent talk is influencing the donor site position. In the context of the presentation of the advantages and disadvantages of STSG, as well as FTSG donor sites, an evaluation of the preferred donor site is necessary. By explaining the patient all possible donor site areas and their associated characteristics, we hypothesize that occipital donor sites are preferred by the patients based on the good clinical results and advantages. We questioned all patients and their accompanied persons referring to our Department of Plastic Surgery in order to clarify the procedure with potential defect coverage including STSGs and FTSGs and to inquire the preferences of different donor sites too. The detailed advantages and disadvantages were clarified. The preferred donor sites for STSG and FTSG donor sites were marked on a data sheet . We collWe evaluated 85 participants  with a median age of 42 years (Mean=46 years). From those, 11.7% had experienced STSG. About 2.4% had experience with full-thickness grafts. Mainly, the Fritzpatrick skin type II  and III  were represented . The definition of skin donor sites (n=188 markings) was mainly based on the physicians’ recommendation , mobility , aesthetic results  and pain  lead to a healing time of approximately 10 to 12 days.11,22 Physiological reasons may be an excellent blood supply as well as the hair follicles and further adnexal structures containing a high amount of epidermal stem cells.15,29,30 Mainly, the hair follicles with stem cells in the bulge region are involved in the proliferation and migration process.12,13,31Hypopigmentation, hypertrophic scars or the rectangular shape of the donor site may be aesthetically not desirable. For the scalp as a donor site for skin grafting, a possible re-grafting was described after 5 to 7 days.9,14 This complication is occurring, if the skin graft is taken too deep or if the patient suffers from postoperative folliculitis. That should be mentioned during the consent information talk with the patient. Postoperative bleeding is proved to be higher in harvesting areas of the thigh, presumably caused by higher tissue movement and tissue stress. In patients with occipital donor sites, microalopecia may occur, even the risk is assessed to be low.Based on our study findings, the decision of skin donor sites is mainly based on the physicians’ recommendation and all donor sites with their advantages/disadvantages and risks should be discussed intensively. Occipital skin donor site should be mentioned explicitly and should be used more frequently in reconstruction of skin defects in reconstructive surgery indications.


The radiological indicators can help doctors determine whether to make tibial tubercle transfer. But which indicator is better is still in question.117 knees in 103 patients who had undergone patellar surgery and 60 knees in 58 patients who had no history of patellar dislocation from 2014 to 2019 were analyzed. Significant differences of tibial tubercle–trochlear groove (TT-TG) on CT and tibial tubercle–posterior cruciate ligament (TT-PCL) on MRI between the case group and the control group were estimated by an unpaired t test. Significant differences between TT-TG on CT and TT-TG on MRI were estimated by a paired t test. The correlation between TT-PCL on MRI and tibial width was estimated by Pearson test. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were measured to assess the diagnostic accuracy of TT-TG and TT-PCL on MRI.p< 0.001). The mean TT-TG difference on CT between the case group and the control group was 5.3 mm, which was significantly bigger than the mean TT-PCL difference on MRI of 1.2 mm(p< 0.001). AUC of TT-TG on CT and TT-PCL were 0.838 and 0.580 (P< 0.001). TT-PCL correlated with tibial width .The intraclass correlation coefficient (ICC) for TT-TG between CT and MRI evaluated by two raters was were 0.566. When comparing TT-TG on CT with that on MRI, the mean difference was 2.5 mm (A statistically significance and a fair ICC proved that TT-TG could not be used interchangeably. The bigger mean difference between the case group and the control group and better AUC proved that TT-TG on CT might be an indicator more suitable for measuring the lateralization of the tibial tubercle. And TT-PCL should be considered as an individual parameter because of the significant correlation between TT-PCL and tibial width. Recurrent patellar dislocation is a common disease, especially in adolescents and young adults whose disease rate can be 29 per 100,000 . SubsequThe cutoff of 20 mm was considered pathological and as an indication for surgery in recurrent patellar dislocation , 6. ReceIn recent years, some literatures proved that the measurement of TT-TG could be influenced by the flexion of the knee, For eliminating such effect, Seitlinger et al. proposed a new measurement-TT-PCL which was defined as the distance between the midpoint of the insertion of the patellar tendon and the medial border of the PCL, and recommended 24 mm as the cutoff value . But BouThe aim of our study was to determine: 1) TT-TG or TT-PCL, which one was more effective in evaluating patellar displacement. 2) confirm the correlation between the TT-PCL and the width of the tibial plateau.Before the research was started, it was approved by the hospital ethics committee. The imaging data including CT and MRI of 161 patients between 2014 and 2019 was reviewed. The case group consisted of 103 patients . They all underwent surgery for recurrent patellar dislocation. The main surgical methods were as follows: medial patellofemoral ligament repair or reconstructions, and / or tibial tubercle osteotomy. The patients were excluded in the following situations: osteoarthritis of the patellofemoral joint, traumatic injury of the tibial tubercle, tibial articular fracture, or previous patellar surgery. The control group consisted of 58 patients . They had normal knees or synovial chondroma or a bone or soft-tissue tumor around the knee joint. The patients were excluded in the following situations: ligament injury, tibial articular fracture, or previous surgery. All the people included in this study had CTs and MRIs. Two reviewers reviewed the imaging data including CT and MRI, one experienced sports medicine doctor and one experienced musculoskeletal radiologist. All measurements were made in a blind manner. One month later, 30 samples were randomly selected and two observers repeated the measures to calculated the intra-observer reliability. The imaging data data were analyzed by the software .The details were seen in Fig. The method of TT-TG measurement was similar to that of Schoettle et al.  Firstly,The method of TT-PCL measurement was similar to that of Anley et al.  Firstly,The method of tibial width measurement was similar to that of Tensho et al.  The measThe patient’s position was supine with knees straight. A 64–detector row Siemens CT scanner  was used for examination. The parameters were as follows: matrix (512 × 512), thickness (1-3 mm), scan time (approximately 5 to 10 s), 0-mm skip between slices, FOV (20) and bone kernel.The patient’s position was supine with knees in a coil. A 1.5-T Siemens MRI scanners  with axial T2 imaging in all cases was used for examination. The parameters were as follows: fast spin echo, repetition time (TR) (3000 to 5000 milliseconds), echo time (TE) (40 milliseconds), thickness (3 mm), scan time (approximately 3-min), 0.6-mm skip between slices, FOV (16), matrix (352 × 288), number of excitations (NEX) (3), and echo train length (ETL) (8 to 10).P< 0.05 was considered significant. In addition, the Pearson correlation coefficient was used to calculate the correlation between TT-PCL on MRI and the tibial width. The intraclass correlation coefficient (ICC) and Bland-Altman plots was used to evaluate the agreement of multiple measurements by different observers on CT and MRI. An ICC value higher than 0.75 indicates excellent agreement. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were measured to assess the diagnostic accuracy of different measurements with the cutoffs calculated.All relevant data were entered in excel and analyzed statistically using IBM SPSS Statics 25 and MedCalc 15.2.2. An unpaired t test was performed to determine significant differences between the different parameters of the case group and the control group. And a paired t test was performed to determine significant differences between TT-TG on CT and TT-TG on MRI. The value of All patients included in this study had patellar dislocation at least twice, which had a significant negative impact on patients’ life. The mean age of the case group in the study was 19 years . There was a total of 28 male and 75 female patients, and 14 of these patients were with bilateral patellar dislocations. The mean age of the control group was 24 years . There was a total of 18 male and 40 female patients, and two of these patients were with bilateral patellar dislocations.p< 0.001). The ICC for TT-TG on MRI was excellent . The ICC for TT-TG on CT was slightly higher than that on MRI. The mean TT-PCL distance of the case group on MRI was 23.0 mm . The mean TT-PCL distance of the control group on MRI was 21.8 mm. The ICC for TT-PCL on MRI  was worse than that for TT-TG on CT or MRI. The details were seen in Tables The mean TT-TG distances of the case group on CT and MRI were 22.1 mm and 19.6 mm, respectively. The mean TT-TG distances of the control group on CT and MRI were 16.8 mm and 14.3 mm, respectively. The intraclass correlation coefficients (ICC) for TT-TG on CT was excellent . The mean difference of TT-TG on MRI between rater A and B was − 0.7 mm .And the mean difference of TT-PCL on MRI between rater A and B was − 1.2 mm . The details were seen in Figs. p< 0.001). The ICC for TT-TG on the two imaging modalities evaluated by rater B was 0.566 . When comparing the TT-TG distance on CT with that on MRI, the mean TT-TG distance between the two imaging modalities was 2.5 mm . There was a significant difference on the TT-TG distance between the two imaging modalities, which indicated the TT-TG distance could not be exchangeable between the two imaging modalities.When evaluating the variability of TT-TG on the two imaging modalities (CT and MRI), the ICC for TT-TG on the two imaging modalities evaluated by rater A was 0.566 . Pearson test proved that TT-PCL had a positive significant correlation with the width of tibial plateau , which indicated TT-PCL should be considered as an individual parameter in recurrent patellar dislocations.The mean tibial width on MRI in the case group was 69.1 mm. The mean width of tibial plateau on MRI in the control group was 70.8 mm . There was no significant difference on the tibial width between the case group and the control group (p< 0.001), which indicated that the diagnostic accuracy of TT-TG on CT was better than that of TT-PCL on MRI. The difference of AUC between TT-TG on MRI and TT-PCL on MRI was 0.234 , which indicated that the diagnostic accuracy of TT-TG on MRI was better than that of TT-PCL on MRI. The details of AUC were seen in Table For the TT-TG distance on CT, the AUC was 0.838. The sensitivity and specificity were 0.68 and 0.9, respectively. For the TT-TG distance on MRI, the AUC was 0.814. The sensitivity and specificity were 0.9 and 0.62, respectively. For the TT-PCL distance on MRI, the AUC was 0.58. The sensitivity and specificity were 0.45 and 0.7, respectively. The difference of AUC between TT-TG on CT and TT-PCL on MRI was 0.258 .Firstly, a statistically significant difference of the mean TT-TG difference (2.5 mm) and only a fair ICC (0.566) for TT-TG between CT and MRI-proved that TT-TG could not be used interchangeably between the two imaging modalities. Secondly, inter-observer reliability for the TT-PCL measurement (ICC=0.712) was worse than that for the TT-TG on CT (ICC=0.914). The mean TT-TG difference between the case group and the control group on CT was 5.3 mm, which was obviously bigger than the mean TT-PCL difference of 1.2 mm. No doubt that the increase of the distance difference between the case group and the control group was helpful for doctors to distinguish the patients from the normal. Thirdly, Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were measured to assess the diagnostic accuracy of TT-TG and TT-PCL on MRI. The results proved that the diagnostic accuracy of TT-TG on CT (AUC=0.838) were better that of TT-PCL on MRI (AUC=0.58). At last, Pearson test was established to prove that there was a positive correlation between the TT-PCL distance and the width of tibial plateau . Considering the low ICC and the significant difference of TT-TG distance between 2 imaging modalities, TT-TG distance between two imaging modalities could not be interchangeable. For the lower values for TT-TG on MRI, it might be caused by increased flexion of the knee with the use of a MRI knee coil [In terms of the reliability of the two imaging modalities for TT-TG, Camp et al.  noted thnee coil .In terms of TT-PCL, Boutris et al.  noted thIn addition, Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were established to assess the diagnostic accuracy of TT-TG and TT-PCL. The AUCs of TT-TG on CT and TT-PCL on MRI were 0.838 and 0.58, respectively, which were approximate to those obtained by Tensho et al. . It was concluded from the above that the diagnostic accuracy of TT-TG on CT was better than that of TT-PCL on MRI. However, when trochlear dysplasia existed, it was difficult to determine the deepest point of tibial tubercle–trochlear groove. In such a situation, TT-PCL was an ideal choice.R=0.455, p< 0.001). Considering this factor, TT-TG should be considered as an individual parameter in recurrent patellar dislocations though it is not affected by the flexion of the knees.Considering the individual difference, TT-PCL ratio was proposed by Tensho et al.  However,The cases included in this study all underwent surgery for patellar dislocation, while the cases in the other studies were described with dislocation more than twice, without illustrating the frequency of dislocation in detail. In clinical setting, the patients choose the surgery as the therapy, always because dislocation so frequently affects the normal life. And TT-TG>20 mm was considered as a standard to make the transferring of tibial tubercle. The patients who underwent surgery for patellar dislocation might be more suitable for the scientific research. This article is limited by the retrospective nature. The position of the knee joint may affect the results of our research.A statistically significance and a fair ICC proved that TT-TG could not be used interchangeably between the two imaging modalities. The bigger mean difference between the case group and the control group and better AUC proved that TT-TG on CT might be an indicator more suitable for measuring the lateralization of the tibial tubercle. And TT-PCL should be considered as an individual parameter because of the significant correlation with tibial width.


Cerebrospinal fluid (CSF) rhinorrhea is a rare complication of macroprolactinomas that, in the vast majority of cases, is subsequent to either medical or surgical intervention. Here, we present the successful management of a rare case of spontaneous, noniatrogenic CSF rhinorrhea in a patient with an untreated macroprolactinoma. A 27-year-old man with no significant medical history presented with six months of persistent CSF rhinorrhea, which was confirmed by testing for beta-2-transferrin. He had had decreased libido since adolescence and impaired growth of secondary sexual characteristics. Workup revealed an elevated prolactin level, and imaging demonstrated erosion of the anterior sellar floor and soft tissue within the sphenoid sinus, concerning for tumor. The patient underwent surgical repair of the CSF leak via a transnasal transsphenoidal approach, with resection and biopsy of tumor material within the sinus. No tumor was noted within the sella itself. The patient tolerated the procedure well and had subsequent normalization of his prolactin level with no further CSF egress. Spontaneous noniatrogenic CSF rhinorrhea, although rare, should be considered in the differential diagnosis of invasive pituitary macroadenomas, especially prolactinomas. The mechanism of CSF leak from a prolactinoma is not completely understood, but the CSF leak should be urgently repaired through a transnasal transsphenoidal approach. Concurrently, tumor resection should be performed and a postoperative lumbar puncture or lumbar drain should be considered to reinforce the skull base reconstruction. Prolactin-secreting adenomas originating from the pituitary gland account for 30-40% of all pituitary adenomas; however, macroprolactinomas  make up a very small subset of these tumors [A 27-year-old man with no significant medical history presented with a persistent severe headache and six months of constant rhinorrhea from his left nostril. He described the drainage as clear and tasteless. He also endorsed generalized fatigue, an inability to grow facial hair, and deficiencies with his libido since he was a teenager. He denied any prior occurrences of prolonged rhinorrhea, breast tenderness, or galactorrhea. His visual examination revealed fully intact visual fields and a benign funduscopic examination. The remainder of his neurologic examination was essentially normal. His prolactin level was elevated to 74.2 ng/mL, and the rest of his hormone panel was unremarkable.A sample of the nasal drainage tested positive for beta-2-transferrin, indicating an active CSF leak from the nostril. Magnetic resonance imaging (MRI) of the brain revealed an enlarged, CSF-filled sella and deviation of the pituitary stalk and gland towards the right. The anterior wall of the sella appeared eroded by a mixed cystic and solid 1.2 × 1.9 × 1.2-cm lesion within the sphenoid sinus along with CSF. Osseous destruction with sclerotic margins could be appreciated at the base of the sphenoid and extending to the medial margin of the left cavernous sinus  across the face of the sinus. A high-volume lumbar puncture was performed after closure to lessen the pressure on the repair. There were no intraoperative complications, and the patient was transferred to the critical care unit in stable condition. On postoperative day two, his prolactin level had decreased to 29.4 ng/mL. He was discharged in stable condition on postoperative day three and had no further recurrence of CSF rhinorrhea.Pathological examination of the resected sample revealed sheets of moderately pleomorphic cells with rare mitosis and no normal pituitary tissue. Immunohistochemistry revealed diffusely positive prolactin staining. Therefore, a diagnosis of prolactin-secreting pituitary macroadenoma was established Figure .Patients with prolactinomas commonly present with early hormonal manifestations of hyperprolactinemia and/or neurological manifestations imposed by tumor-imparted mass effect. Although it can result in galactorrhea, hyperprolactinemia in males manifests most appreciably as hypogonadotropic hypogonadism and decreased libido . These sSpontaneous CSF leaks have been previously reported after medical management of prolactinomas, especially larger lesions ,9. ProlaIn the absence of medical or surgical intervention, the underlying pathophysiology of spontaneous CSF rhinorrhea is less clear. Ohtakara et al.  hypothesThe presence of an empty-appearing sella on imaging in the setting of a persistent headache, rhinorrhea, and mild visual field defects also raised concern for idiopathic intracranial hypertension (IIH) and was therefore ruled out in this case. An empty sella is radiographically found in 77% of patients with IIH and represents elevated intracranial pressure compressing the pituitary gland along the sellar floor . Atci etIn cases of spontaneous CSF fistula, rapid diagnosis and surgical intervention to repair the leak are critical regardless of the cause. Untreated CSF egress is associated with a high risk of meningitis, pneumocephalus, or development of an intracranial abscess . The oveSpontaneous noniatrogenic CSF rhinorrhea, although rare, should be considered in the differential diagnosis of invasive pituitary macroadenomas, especially prolactinomas. The mechanism of CSF leak from a prolactinoma is not completely understood, but the CSF leak should be urgently repaired through a transnasal transsphenoidal approach. Concurrently, tumor resection should be performed, and a postoperative lumbar puncture or lumbar drain should be considered to reinforce the skull base reconstruction.


Spearman’s correlation showed that NFL is an independent predictor of neurological disability in the MS group. Significant correlations were found between NFL, neopterin, and QUIN, and between kynurenine and neopterin. Receiver operating characteristic (ROC) curve analysis was used to plot the top three best predictors of MS-related disability that yielded the best specificity and sensitivity. Normalized NFL (AUC: 0.923), QUIN (AUC: 0.803), and neopterin (AUC: 0.843) were the best independent predictors of neurological disability in pwMS. The CSF NFL and CSF QUIN, together with neopterin, were elevated in the CSF of pwMS compared to controls. The combination of the neurodegenerative biomarkers together with biomarkers of neuroinflammation could provide additional information on the underlying pathomechanism of disease activity, which is essential for the identification of patients at risk of developing cumulative disabilities. Neurofilament light (NFL) has proved to be a good prognostic factor in multiple sclerosis (MS), as its level is proportionally elevated with extended neuraxonal damage. The involvement of the kynurenine pathway in neuroinflammation has been proved. The precursor of this pathway is the essential amino acid tryptophan, which is catabolized 95% towards kynurenine metabolites. Quinolinic acid (QUIN) within the brain is only produced in activated microglia and macrophages, leading to axonal degeneration via the activation of N-Methyl-D-aspartate receptors. Neopterin is a biomarker for inflammation produced by macrophages. The association of these biomarkers has not previously been investigated. Our aim was to assess whether there is an association of the neurodegenerative biomarker NFL with the markers of neuroinflammation, e.g., kynurenine metabolites and neopterin, in the cerebrospinal fluid (CSF). CSF samples of patients with MS (pwMS;  Neurofilament light chains (NFLs), which belong to the 68 kDa-sized members of the family of filament proteins , form thindoleamine-2,3-dioxygenase (IDO). Its metabolite, quinolinic acid (QUIN), is produced by activated microglia and resident macrophages in the central nervous system (CNS), but not by neurons and astrocytes. QUIN is involved in neuronal death; it acts as an agonist of N-methyl-D-aspartate (NMDA) receptors [The kynurenine pathway leads to nicotinamide adenine dinucleotide (NAD+) production by degradation of the essential amino acid tryptophan, which is a precursor for serotonin and melatonin as well . Tryptopeceptors ,7 and dieceptors ,9. It aceceptors ,11 in execeptors . Neoptereceptors ,14.We analyzed data from patients with MS (pwMS) regarding NFL levels in the CSF at diagnostic lumbar puncture (LP) and compared them with tryptophan, kynurenine pathway metabolites, and neopterin in the CSF, retrospectively. As extensive research supported that NFL proved to be a stable, reliable biomarker in MS, especially in the CSF for axonal damage, it served as a proven biomarker for comparison. We hypothesized that elevated quinolinic acid and decreased kynurenic acid levels in the MS group would reflect the pathological processes. A positive correlation of these biomarkers involved in neurodegeneration (NFL) and neuroinflammation (QUIN and neopterin) was expected in pwMS when compared to the control group. p < 0.0001, median ± SEM 3280.36 ± pg/mL vs. 572.50 ± 70.23 pg/mL). As linear regression with adjusted R-squared values showed age-dependent changes with regard to NFL , we corrected for this effect. The age-corrected NFL values for pwMS were 3021.65 ± 410.13 pg/mL vs. 547.19 ± 66.36 pg/mL (mean ± SD) for controls.We measured the NFL level in 37 CSF samples of pwMS and 22 CSF samples of controls  AUCt-tests. For multiple comparisons, the p value was considered significant if the p value was less than 0.00625 (p < 0.05/8).The CSF values of tryptophan, kynurenine metabolites, and neopterin of the 37 pwMS and 22 controls are highlighted in NFL proved to be an independent parameter in the MS group. The correlations between the different metabolites and NFL are shown in A receiver operating characteristic (ROC) curve was used to plot the true positive rate vs. the false positive rate of the different measured parameters. It depicts the cumulative distribution function of the detection probability on the y-axis and the cumulative distribution function of the false-alarm probability on the x-axis. Normalized NFL (AUC: 0.923), QUIN (AUC: 0.803), and neopterin (AUC: 0.843) were the top three best predictors of MS-related disability according to ROC curve analysis among the eight observed values .p < 0.001): for tryptophan r2 = 0.128; y = 9.42*1016-0.57 * x; for kynurenic acid r2 = 0.128, y = 9.423*1016-0.57 * x; and for QUIN r2 = 0. 405, y =−1.23*10-15 + 0.09 * x.The expanded disability status scale (EDSS) point at the time of LP correlated well with tryptophan, kynurenic acid, and QUIN levels  leads to ongoing accumulation of disability in progressive as well as in relapsing forms of the disease. This chronic condition is characterized by ongoing brain tissue damage, also regarded as faster aging ,42,43. OJust as in a recent study in which association between serum NFL and QUIN levels was found in preclinical Alzheimer’s disease , we founThis study was approved by the local ethical committee (No. 143/25.06.2015). All patients participated voluntarily and gave their informed consent at the admission to the hospital for carrying out medical examinations, for collecting sera and CSF samples for our biobank at lumbar puncture (LP), or later during follow-up. The samples were processed and analyzed according to the international standardized biobanking consensus protocol of the BIOMS-Eu network .Inclusion criteria for MS patients were age > 18 years, LP at diagnosis, at least a 12-month follow-up, and available samples in the biobank obtained between 2012 and 2018. The patients were prospectively followed up, meeting an MS specialist at least four times a year. The diagnosis was based on the revised McDonald criteria , which an = 37) were compared with age and gender-matched controls (n = 22) with symptomatic neurological disorders  and patients with non-inflammatory neurological diseases , and followed for at least 2 years to exclude other underlying pathologies. Patients with known diseases of predictably high NFL levels were excluded .To rule out age-related differences, the CSF samples of pwMS  at 405 nm; CV < 1% (1.5–2 Abs) at 405 nm; accuracy ± 2.0% or ± 0.007 Abs whichever is greater, typical value ± 1% (0–2.0 Abs) at 405 nm. The detection limit of this method is given as the limit of quantification of the assay, which was 310 pg/mL. The inter and intraassay variations were below 10%.CSF NFL levels were measured with a commercially available sensitive sandwich ELISA kit  using a Multiskan Parallel to the NFL analysis, CSF samples were measured for kynurenine pathway metabolites.All reagents and metabolites were analytical reagent grade and were purchased from Sigma-Aldrich or Merck. Deuterated internal standards were purchased from Cambridge Isotope Laboratories and Medical Isotopes Inc. Concurrent analysis of tryptophan, kynurenine, quinolinic acid, kynurenic acid, picolinic acid, 5-hydroxyindoleacetic acid, and neopterin was performed with LC-MS/MS as described by Fuertig et al. , using aStatistical calculations were performed with the IBM SPSS Statistics 24 software .p = 0.016; r2 linear = 0.297, y = 1.28*102 + 15.77 * x) and served as a basis for normalization for further use.Except in the case of NFL, all measured parameters had normal distribution in both patients and controls. Therefore, Mann–Whitney U test was performed for NFL, and the data were presented in median ± SEM. For the other parameters independent sample t-test was used, and the values were given in mean ± SD. NFL proved to be age dependent by linear regression  curve was used to plot the true positive rate vs. the false positive rate of the different measured parameters.The recent diagnostic criteria of MS  enable tReliable biomarkers are needed which could additionally direct attention towards patients who need highly effective disease-modifying treatment at the early stages of the disease.


PD patients exhibited higher pS129-α-syn/α-syn ratios compared to FTD (p = 0.045), after exclusion of samples with CSF blood contamination. When comparing movement disorders , MSA patients had lower α-syn levels compared to CBD (p = 0.024). Patients with a synucleinopathy (PD and MSA) exhibited lower t-α-syn levels  and higher pS129-/t-α-syn ratios  compared to patients with tauopathies (PSP and CBD). There are no significant α-syn species alterations in non-synucleinopathies.Total CSF α-synuclein (t-α-syn), phosphorylated α-syn (pS129-α-syn) and α-syn oligomers (o-α-syn) have been studied as candidate biomarkers for synucleinopathies, with suboptimal specificity and sensitivity in the differentiation from healthy controls. Studies of α-syn species in patients with other underlying pathologies are lacking. The aim of this study was to investigate possible alterations in CSF α-syn species in a cohort of patients with diverse underlying pathologies. A total of 135 patients were included, comprising Parkinson’s disease (PD;  Diagnostic accuracy of cognitive and movement disorders based on established clinical diagnostic criteria is suboptimal, even among experts ,2,3,4. TBiomarkers that provide in vivo information of the underlying pathology in patients with cognitive and movement disorders are needed in order to improve diagnostic accuracy. Cerebrospinal fluid (CSF) biomarkers have been extensively studied to this end, due to their relatively low cost , safety of lumbar puncture and the proximity of CSF to brain parenchyma.42), a marker of amyloid pathology (plaque formation); total tau protein (τT), a non-specific marker of neurodegeneration; phosphorylated tau protein at threonine 181 (τP-181), a marker of tau pathology (tangle formation). AD is characterized by a decrease in Aβ42 and an increase in τT and τP-181, which results in elevated biomarker indices such as τT/Aβ42 and τP-181/τT ratios.CSF biomarkers have already been incorporated in the NIA/AA and IWG-2 diagnostic criteria for Alzheimer’s disease (AD) ,6. TheseDespite the success of CSF and imaging biomarkers in AD, clinically relevant biomarkers in synucleinopathies, such as Parkinson’s disease (PD), Parkinson’s disease dementia (PDD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA) are still lacking.α-synuclein (t-α-syn) has been studied as a surrogate biomarker of synucleinopathies [α-syn is decreased by 10–20% in PD compared to healthy subjects and other neurodegenerative disorders. However, there is considerable overlap among neurodegenerative diseases, resulting in suboptimal diagnostic accuracy. Results on other synucleinopathies such as DLB and MSA have produced mixed results [CSF total opathies ,9,10,11. results ,8,9.α-syn species underlie and drive the neurodegenerative process in synucleinopathies [α-synuclein species have been tested as biomarkers of synucleinopathies, with mixed results. These studies point towards an increase in CSF pS129-α-syn and/or o-α-syn in PD and other synucleinopathies [Substantial evidence supports the notion that oligomeric (o-) and phosphorylated Ser129 (pS129-) opathies ,14 and vopathies ,16,17,18α-syn species among other proteinopathies, such as tauopathies [α-syn or unchanged o-α-syn levels compared to patients with PD, PDD or DLB.Most studies on CSF α-syn species have focused exclusively on synucleinopathies. Few studies have compared opathies ,19. Limiα-syn is elevated in AD compared to healthy controls, and that t-α-syn may correlate with τT in AD. Moreover, a significant increase in t-α-syn has been reported in Jacob–Creutzfeldt disease, as is the case for τT. These findings may imply that t-α-syn could represent a non-specific marker of neurodegeneration, as is the case for τT. CSF α-syn species have not been systematically studied in neurodegenerative disorders of different underlying pathologies.Intriguingly, it has been suggested that t-α -syn  in a cohort of patients with cognitive and/or movement disorders of diverse underlying pathologies (synucleinopathies and tauopathies), AD (a mixed tauopathy and amyloidosis) and vascular dementia. A secondary objective was to explore any possible correlations between α-syn species and established CSF AD biomarkers . We also investigated if any correlations with clinical parameters and α-syn species are present.The primary aim of this study was to investigate the diagnostic accuracy of three different species of T, τP-181, Aβ42), examined at the Wards of Cognitive and Movement disorders of the First Department of Neurology of the Medical School of the National and Kapodistrian University of Athens at Eginition Hopsital, between 2011 and 2017, were retrospectively reviewed. Patients fulfilling established clinical diagnostic criteria for clinically established PD [The medical files of all patients, with available CSF AD biomarkers  [Τ ≤ 376 pg/mL; τP-181 ≤ 57 pg/mL; Aβ42 ≥ 682 pg/mL). In the absence of pathological data, these patients were excluded from analysis, because they may represent AD patients with atypical clinical presentation  or patients with dual pathologies.Patients with a typical CSF AD profile (defined as elevated τed Aβ42) ,27 and aα-syn were measured including t-, o- and pS129-α-syn following previously published sandwich-based enzyme-linked immunosorbent assays (ELISA) [Different species of CSF  (ELISA) . For allT, τP-181, Aβ42) were measured in duplicate by double sandwich, ELISA by commercially available kits  according to manufacturer instructions. A protocol controlling for pre-analytical and analytical variability was implemented, with regard to classical CSF biomarker analyses [AD CSF biomarkers  as appropriate. Neuropsychological and movement disorder test scores were compared by analysis of covariance (ANCOVA), with sex, age and disease duration as covariates or independent samples Kruskal-Wallis test as appropriate.Shapiro–Wilk’s and Levene’s tests were used to test for normality of distribution and homogeneity of variance, respectively. Demographic and clinical data among study groups were compared by T, Aβ42, τP-181, pS129-α-syn and O-α-syn/α-syn ratios. These variables were analyzed by ANCOVA, with sex, age and disease duration as covariates. Post-hoc analysis with Bonferroni correction for multiple comparisons was applied. All other CSF biomarkers were compared by Kruskal–Wallis, as appropriate.CSF biomarkers did not have normal distributions. Log-transformation restored normality of distributions for τT, τP-181, Aβ42, α-syn, pS129-α-syn and o-α-syn, the following ratios were calculated: τT/Aβ42, τP-181/τT, pS129-α-syn/a-syn and o-α-syn/α-syn.In addition to τThe following analyses were performed: (a) an initial analysis included all study groups; (b) patients with movement disorders ; (c) patients with dementia ; (d) patients based on presumed underlying proteinopathy .α-syn species, after exclusion of patients with CSF blood contamination. This was defined as RBC > 50 cells/mm3, as this cut-off value was determined to minimize the effect of CSF blood contamination in α-syn levels [These analyses were repeated for n levels . Non-parIn cases of statistical significance, Receiver Operating Characteristics (ROC) Curve analysis was performed to define the cut-off point that provided optimal combined sensitivity and specificity.p < 0.001 for correlation analyses.Spearman’s rank correlation coefficient was applied to investigate possible correlations between CSF biomarkers and clinical data, as well as among CSF biomarkers within different study groups. To correct for multiple comparisons, significance level was set at ® version 23.0.0.0 . Graphs were designed using GraphPad Prism®, version 5.03 .Analyses were performed by IBM SPSS Statisticsn = 13), MSA (n = 9), PSP (n = 13), CBD (n = 9), AD (n = 51), FTD (n = 26) and VD patients (n = 14). The study groups differed in age (p = 0.001), disease duration , MMSE score (p < 0.0001), Clox 2 test (p = 0.002) and 5-word delayed recall test (p = 0.003). Post-hoc analysis revealed that VD patients were older than PD (p = 0.011) and FTD patients (p = 0.014). AD patients performed poorer in neuropsychological tests compared to other study groups . Post-hoc analysis revealed that PD patients had significantly higher ratios compared to FTD (p = 0.045)  .Τ, τP-181, Aβ42, τT/Aβ42 ratio and τP-181/τT ratio (p < 0.0001). Post-hoc analysis revealed that these differences were attributable to AD patients, who had: (a) higher τT levels compared to MSA (p = 0.003), PSP (p < 0.0001), PD (p < 0.0001), FTD (p = 0.001) and VD (p = 0.012); (b) higher τP-181 compared to MSA (p = 0.0020), PSP (p < 0.0001), PD (p = 0.036) and FTD (p < 0.0001); (c) lower Aβ42 levels compared to CBD (p = 0.039), PSP (0.018), PD (p = 0.027) and FTD (p < 0.0001); (d) higher τT/Aβ42 ratio compared to PD and PSP (p < 0.0001) and FTD (p = 0.001); e) higher τP-181/τT compared to PD (p = 0.016)  .α-synuclein species, when all patients were included (α-syn differed significantly among study groups (p = 0.016). This was attributed to lower α-syn levels in MSA compared to CBD (p = 0.024) . There was no statistically significant difference regarding included . After e= 0.024) , Table 2Τ and the τT/Aβ42 ratio. Post-hoc analysis revealed that these differences were due to higher τT levels in CBD compared to PSP (p = 0.017) and higher τT/Aβ42 ratios in CBD compared to PD (p = 0.002) and PSP (p = 0.046)   . The thiT ratio) .α-syn was significantly lower in presumed synucleinopathies compared to presumed tauopathies (p = 0.034). ROC curve analysis revealed that a value of t-α-syn ≤ 865 pg/mL provided a sensitivity of 86% and a specificity of 59% for a synucleinopathy diagnosis . CSF t-iagnosis .α-syn levels (p = 0.002) and higher pS129-/t-α-syn ratios (p = 0.020). ROC curve analysis indicated that t-α-syn ≤865 pg/mL produced a 95% sensitivity and 69% specificity for a synucleinopathy diagnosis. A pS129-α-syn/α-syn ratio value ≥0.122 provided 71% sensitivity and 77% specificity for a synucleinopathy diagnosis . In this cohort, synucleinopathies exhibited significantly lower t-iagnosis .T correlated significantly with τP-181 , τT and Aβ42  and τP-181 and Aβ42 . There were no correlations between CSF biomarkers in any of the other study groups. CSF biomarkers did not correlate with any of the clinical or demographic characteristics in any of the study groups  are presently lacking.The in vivo recognition of the underlying pathology in neurodegenerative disorders is the initial step towards the development of disease-modifying, protein-targeted treatments. To this end, CSF Aβα-syn species have been studied to this end, including t-α-syn, and, more importantly, o-α-syn and pS129-α-syn. Most studies in the field have focused on differences of α-syn levels and species among synucleinopathies, or between synucleinopathies and AD or PSP, reporting lower t-α-syn and higher pS129-α-syn and o-α-syn values in synucleinopathies [α -Syn oligomers were increased in plasma of PD and brain extracts of DLB patients [α-syn species in a variety of movement and cognitive disorders is presently lacking.CSF opathies ,16,28,33patients ,35. A coα-syn species  in a variety of neurodegenerative disorders of presumed underlying proteinopathy. These included synucleinopathies , tauopathies  and mixed tauopathy with amyloidosis (AD). Moreover, we further included patients with FTD (either 3R-tauopathy or TDP-43-proteinopathy) and VD, as paradigms of diseases with neuronal death due to neurodegeneration and ischemia, respectively.The present study examined CSF α-syn was numerically lower and the pS129-α-syn/α-syn ratio higher in patients with PD and MSA compared to other study groups. These differences reached statistical significance when patients were grouped based on their presumed underlying proteinopathy , with suboptimal specificity. Importantly, when patients with CSF blood contamination were excluded, these differences in α-syn and pS129-α-syn/α-syn ratio were more pronounced, providing improved sensitivity and specificity for a synucleinopathy diagnosis. Still, it has to be noted that o-α-syn and pS129-α-syn were not different between synucleinopathies and tauopathies, and that the main determining factor of differentiation between the two groups was t-α-syn. This index may prove useful, in conjunction with other markers, in the differentiation of PD and MSA on the one hand, and PSP and CBD on the other, a distinction that is not always easy on clinical grounds.In our cohort, CSF t-α-syn and an increase in pS129-α-syn and o-α-syn in PD [α-syn species values among synucleinopathies and other proteinopathies. Thus, at present, CSF α-syn species cannot be utilized as clinically relevant biomarkers for the differentiation of synucleinopathies from other disorders, due to their suboptimal diagnostic accuracy. This is partly due to the great variability of α-syn species among patients with PD, as noted elsewhere [Our findings are in agreement with the literature, with most relevant studies reporting a decrease in yn in PD ,8,9. Deslsewhere .α-syn alterations in non-synucleinonopathic disorders in our cohort . This is in general agreement with the literature [α-syn and tau oligomers [pS129-α-syn correlated with Braak stage and Ab levels in another study [α-syn has also been reported in AD [α-syn species and classical CSF biomarkers in the AD cohort. However, in the absence of a control group, CSF α-syn species alterations in non-synucleinopathies could not be further studied in this cohort.Importantly, there were no significant t-terature ,10,16. Aterature . Moreoveligomers , whereaser study . A correed in AD . In the α-syn and the pS129-α-syn/α-syn ratio after excluding patients with CSF blood contamination  in our cohort, re-emphasizes the need for standardization of pre-analytical factors in CSF biomarker studies [α-syn species could in part be attributed to this diversity of peri-analytical factors. These factors may include time of lumbar puncture, type of tubes used for CSF collection, blood contamination of CSF, CSF samples storage and shipment protocol, sample thawing procedure etc. [The significant improvement of diagnostic accuracy of  studies . The disure etc. . More imure etc. .pS129-α-syn correlates with clinical severity in PD, as measured by the UPDRS [pS129-α-syn with PD disease progression has also been supported [o-α-syn correlated with PD motor severity in another study [state or stage markers [α-syn species did not correlate with any clinical feature . This is in agreement with a study by Foulds et al., where α-syn exhibited stability over PD disease progression [α-syn species determinations over different PD disease stages, could provide robust data regarding possible correlations between α-syn species and PD severity.There have been reports regarding correlations of biomarkers with clinical features. More specifically, it has been postulated that he UPDRS . An incrupported . Moreoveer study . Phospho markers . This co markers ,43,44. Igression . HoweverT values compared to PSP and τΤ/Aβ42 ratios compared to PD and PSP. A relative increase in τT in CBD has been reported previously. The relative increase in τT in CBD is difficult to interpret, particularly when considering that no significant CSF τT alteration is evident in PSP, another 4R-tauopathy [The main focus of this study was the significance of α-syn species as possible biomarkers in neurodegenerative disorders. However, in the cohort of patients with movement disorders, CBD patients had significantly higher τauopathy ,45.This study has certain limitations. Initially, the number of patients per study group is suboptimal. This is expected in a single-center cohort, due to the rarity of some of these disorders  and due to methodological issues . Studies of larger cohorts could provide more robust information. Secondly, the absence of a control group precludes the direct comparison of study groups to healthy controls. The inclusion of a control group could further assist in disentangling the complex interplay between CSF biomarkers, clinical phenotype and underlying pathology. Lastly, all diagnoses were based on clinical criteria. To optimize the diagnostic accuracy, all patients fulfilled probable diagnostic criteria and were followed up to exclude patients with atypical clinical features. Moreover, all patients with a non-amnestic phenotype and typical CSF AD profile were excluded, thus minimizing the possibility that the included subjects represented atypical species of AD.α-syn species in a variety of neurodegenerative disorders of diverse underlying pathologies and investigates any possible correlations of them with classical CSF AD biomarkers and clinical features. Larger studies with neuropathological data are needed to establish the relationship of CSF biomarkers, clinical phenotype and the underlying pathology.Despite these shortcomings, the present study provides data on CSF Synucleinopathies exhibit lower t-α-syn and higher pS129-α-syn/t-α-syn ratios compared to tauopathies. CSF blood contamination is a major cofounding factor in α-syn species measurements. Non-synucleinopathic disorders do not present with significant CSF α-syn species alterations.


Post-operative CSF leak still represents the main drawback of Endoscopic Endonasal Approach (EEA), and different reconstructive strategies have been proposed in order to decrease its rate.To critically analyze the effectiveness of different adopted reconstruction strategies in patients that underwent EEA.Adult patients with skull base tumor surgically treated with EEA were retrospectively analyzed. Data recorded for each case concerned patient demographics, type of surgical approach, histotype, anatomical site of surgical approach, intra-operative CSF leak grade (no leak (INL), low flow (ILFL), high flow (IHFL)), reconstructive adopted strategy, Lumbar Drain positioning, post-operative CSF leak rate and intra/post-operative complications.A total number of 521 patients (January 2012-December 2019) was included. Intra-operative CSF leak grade showed to be associated with post-operative CSF leak rate. In particular, the risk to observe a post-operative CSF leak was higher when IHFL was encountered  16.25). In particular, vascularized multilayered reconstruction and fat use showed to be effective in lowering post-operative CSF leaks in IHFL (p 0.02). No differences were found considering INL and ILFL groups. Yearly post-operative CSF leak rate analysis showed a significative decreasing trend.Intra-operative CSF leak grade strongly affected post-operative CSF leak rate. Multilayer reconstruction with fat and naso-septal flap could reduce the rate of CSF leak in high risk patients. Reconstructive strategies should be tailored according also to the type and the anatomical site of the approach. Midline skull base tumors are rare lesions, characterized by different grades of malignancy and recurrence rate . The oncPostoperative cerebro-spinal fluid (CSF) leaks still represent the main drawback of the endoscopic endonasal approach –9. Its rThe aim of this study is to critically analyze the effectiveness of various adopted reconstruction strategies on the post-operative CSF rate in patients undergoing EEA in a single center experience (2012–2019), operated by a consolidated ENT-Neurosurgical team.The secondary goals of this study are to analyze the relationships between the post-operative CSF leak and (1) the type of surgical approach, (2) the anatomical site of the approach, (3) the grade of intra-operative CSF leak (IOL), (4) the history of previous trans-sphenoidal surgery and radiotherapy, (5) the peri-operative lumbar drain (LD) positioning and (6) the surgeon’s experience and learning curve.This is a retrospective observational study analyzing data of 566 patients affected by skull base neoplasms who underwent EEA between January 2012 and December 2019.Inclusion criteria were: 1) history of skull base surgery, in adults (>17 years), 2) performed with 3D-EEA and 3) at least a 3-month follow-up. Exclusion criteria were: 1) Not complete availability of patient’s clinical and radiological data; 2) the presence of complex CVJ malformations; 3) the absence of the Senior Surgeon (FZ) during the procedure.Data were extracted from a prospective collected on-line and shared database, filled during patient’s hospitalization and follow-up, and included: age, sex, tumor histology, type of endoscopic endonasal approach (standard or extended), location of the osteo-dural defect according to the site of the approach, presence of intra-operative CSF leakage, different reconstruction techniques, perioperative lumbar drain (LD) positioning, postoperative CSF leakage rate, occurrence and type of intra and post-operative complications and occurrence of radiotherapy before surgery. Clinical and radiological data were obtained at the time of admission and at the follow-up evaluation by fully trained neurosurgeons.https://molinette.codize.app) that is shared among physicians belonging to the authors’ institution; the database itself is not publicly available according to the privacy policy of the authors’ institution. Moreover, data have been anonymized before being accessed and analyzed.In particular, data have been collected in an on-line database , intra-operative low flow CSF leaks (ILFL) and intra-operative high flow CSF leaks (IHFL). As commonly accepted , 16, ILFSkull base reconstruction strategy was divided according to 1) size of defect; 2) anatomical site of surgical approach; 3) grade of IOL and 4) type of tumor. Available methods to plan proper reconstruction strategies were : A) SyntThe strategies adopted for reconstruction in this series were summarized in 3 major groups :Minimal Reconstruction: in cases with a small intracranial opening without CSF leakage, a sponge was used to fill the surgical cavity fixed with fibrin glue. Mucosal flap from sphenoid sinus could have also been used in this strategy (when/if preserved).Standard Reconstruction: dural synthetic substitutes were used for small intracranial openings and for ILFL. In this group autologous abdominal fat and inferior or middle turbinate mucosa was often used respectively to fill the cavity and to cover the defect. Fibrin glue was then used to adhere the dural substitute and fat together. Additionally, patients belonging to the INL* subgroup, who underwent fat and/or reconstruction, have been included in this group as “incomplete type 2 reconstruction”.“Sandwich” Multilayered reconstruction : this stNonetheless, although the aforementioned strategies were adopted in the majority of cases, several not standardizable combinations of available materials could have been used for borderline cases (incomplete type 2 and 3 reconstructions).The type of surgical approach and consequent probability for high flow CSF leak represented the criteria for Lumbar Drain (LD) positioning. More specifically, it was used in every expanded approach with osteo-dural defect in the anterior cranial fossa, in the clival region and in the sellar region, and/or when supra-sellar extension was needed (trans-tuberculum and trans-planum approaches). LD was positioned before surgery, under general anesthesia and opened only after surgery.Descriptive statistics were reported as mean and standard deviation for continuous variables. Comparison of proportions were performed with Chi-squared test for categorical variables and, when needed , with Cramer’s Phi and V coefficients to verify association between variables. Relationships between dependent and independent variables were evaluated using logistic regression. Moreover, 3 casual extractions from the database were made in order to obtain parametric variables. Statistical significance was defined with a p-value < 0.05. All statistical analyses were performed using SPSS Statistics software.A total of 521 patients  were collected after retrospective evaluation of inclusion/exclusion criteria. Descriptive data of the study population and surgical results are reported in Analyzing different types of tumors, a statistically significant association between POL and craniopharyngioma diagnosis was registered . .Associations between POL rate and the grading of IOL, the type and the site of surgical approach are reported in Patients were stratified in different categories according to the statistical weight of the grade of IOL. In the standard approach group, POL rate was 1.8% when IFL was encountered, 12.1% (8 patients) when ILFL was reported and 83.3% (5 patients) in cases of IHFL (p.001). In the expanded approach group, POLs rate was 0% when IFL or ILFL was registered, reaching 17.8% (8 patients) when IHFL was encountered during surgery (p.002) .No statistically significant differences between post-operative CSF rate and type of reconstruction were found after stratification in patients with INL or ILFL. Moreover, among patients belonging to INL leak, 102 (26.8%) underwent incomplete type 2 or type 3 reconstruction. In this subgroup POL rate was 1.9% and there was no significative difference compared to POL rate in the type 1 reconstruction (1.4%).Conversely, while analyzing patients with IHFL and their POL rate, statistically significant differences were found comparing different reconstructive strategies. POL rate resulted 4.3% in type 3 reconstruction group, while it was 42.9% in patients where type 1 or type 2 strategies were adopted (p.002). Moreover, univariate logistic regression showed significant influence of fat used in type 3 reconstruction (Exp(B) 0.58; p.001) .Focusing on the role of fat grafts, results confirmed a paramount difference between the presence/absence of IHFL: a statistical significance was reported in the IHFL group  .Moreover, in the same IHFL group, a significant difference of POL rate was found in patients when 2 dural substitutes were used (0%) compared to patients with different multilayer combination (32.4%) (p.010) .LD positioning was analyzed according to different IOL grade. No significant statistical differences were found in the ILFL nor the IHFL groups .Finally, POL rate was considered through the years showing a decreasing trend in the last 4 years, from the highest value of 14.7% reported in 2016 to the lowest value of 2% registered during 2019 (p.020) .The endoscopic endonasal approach (EEA) have evolved during the years, allowing the treatment of complex skull base lesions . MinimalNevertheless, POL related complications such as meningitis and pneumocephalus still remain the main drawbacks of EEA –20. TherIn order to achieve a good reconstruction, the primary goal should be re-creating a physiological separation between intracranial and extracranial spaces . To achiThe development of different materials and different strategies for reconstruction resulted in reduction of POL rate, from the higher values reported in the first papers (10%–40%) , 23–35, Many reconstructive methods and different materials have been reported in the literature , 15 but Hadad et al. described in 2006 a novel technique for reconstruction of skull base defect using a pedicled NSF, harvested from the nasal septum and vascularized by sphenopalatine branches which provided a reported 5% of postoperative CSF leak rate .Wormald et al. reported the “bath-plug” technique, Leng at al. defined the “gasket seal” closure, Amit et al. described the “champagne cork” technique (CCT), while recently, Cavallo et al. have reported the “3F” strategy (fat—flap—flash) , 27–29.Common principles of new strategies involve (1) filling the empty dead space, (2) obtaining a watertight closure and 3) creating meticulous multilayer dural closure to reduce the entity of intra-operative CSF flow acting on the skull base defect  creating, 18.In addition, different soft materials have been described for dural reconstruction, fat and ITT were the most used , 29. ITTAccording to the literature, a graded approach to skull base repair after endonasal surgery should be considered in the endoscopic era . EspositIn this study, Grade 1 or 2 of the Esposito’s system were considered a low flow CSF leak (ILFL), while Grade 3 were considered a high flow leak (IHLF), as reported in other papers .The literature results showed that multilayered closures could be considered essential in the reconstructive phase of EEA in both cases of ILFL and IHFL , 12, 21.In this series, IOL grade could be considered the main predicting factor for POL risk .POL rate, resulted higher in the IHFL group (25.5%) than in both the ILFL and INL groups (10.5% and 1.5% respectively) . MoreoveThis result could be considered as another validation of the crucial role of CSF leak flow acting on skull base osteo-dural defect and it should be carefully analyzed during reconstruction planning.Anatomical site and type of surgical approaches still remain a critical aspect of reconstructive algorithm . Indeed,In this series, the type of IOL was found to have a key role in determining significant differences among different anatomical sites of the approach , Fig 2. These results further highlight the importance of IOL grade in predicting POL risk, considering different surgical approaches, in order to choose the best strategy for reconstruction.Synnderman et al. recently reviewed different reconstructive strategies for anterior and posterior cranial fossa. A three-layer reconstruction with dural substitute, fascia lata and NSF was described for the anterior cranial fossa , 10, whiIn this series, reconstructive strategies were prevalently chosen according to expected IOL grade.POL rate resulted higher in type 3 reconstruction (13%) than in type 2 (6.5%) and type 1 reconstruction (1.7%). This result could be linked to the fact that type 3 reconstruction was used predominantly for procedures with larger osteo-dural defects and higher IOL grades. Moreover, in addition to the volume of the defect that could increase the POL rate, as recently described by Turri-Zanoni , it is wAgain, the same results were not significant in patients with both low flow or no IOL, further strengthening the role of this aspect in analyzing different strategies for multilayer reconstruction .To summarize, “sandwich” multilayer reconstruction with vascularized flaps should be always considered when IHFL occurs or could be planned considering the type and the anatomical site of surgical approach. The accuracy of different layers positioning and the capability to fill the empty dead space could be considered the target, in order to reduce the CSF flow acting on the skull base defect.In this study LD was placed predominantly in patients who underwent expanded EEA, according to different IOL grade .The rate of post-operative CSF is reported in LD positioning during EEA has been debated in literature and no agreement has been found yet , 37–39.Recently Zwagerman et al. published a prospective, randomized controlled trial reporting that perioperative LD, used in the contest of NSF and multilayered reconstruction, significantly reduced the rate of postoperative CSF leaks among those patients who might to have high risk of CSF leak  . NonetheIn contrast, Eloy et al. retrospectively review 59 patients who underwent EEA repair of high flow CSF leak with NSF without LD, reporting 0% of POL rate, even if the majority of patients had sopra-sellar pathologies .In this study, no significative statistic differences were found between LD and no LD group. Considering the IHFL group, POL rate resulted lower in LD positioning group (23.5% vs 29.4%), although this difference did not reach the statistical significance. Thus, no conclusions about the utility of LD positioning could be drawn from this study, even if results seem to support a contribution in reducing POL rate, especially in IHFL group.No association between LD and meningitis was found in this study, despite the literature reports a positive correlation between longer duration of LD and higher rate of infections .Re-do surgeries and radiotherapy were considered a significant part of skull base tumors management, so their impact on POL have been analyzed in different studies , 42. NisA decreasing trend in POL rate was observed during the years   and thesPrincipal limitation of this study is its retrospective nature. The choice of reconstructive strategy and general management were made in absence of a standardized protocol. Moreover, the adopted reconstructive strategies, summarized in Another limitation of this study lies in the fact that a consistent subgroup of patients who underwent minimal skull base reconstruction have been included. Nonetheless, albeit it is widely accepted among skull base surgeons that small sellar defects without intra-operative CSF leak might not need reconstruction, the risk of post-operative leak could not be considered nil among these patients. Moreover, the presence of small dural tears or coexisting independent risk factors for CSF leak could explain the reported rates of POL. Besides, although the use of fibrin glue and sphenoidal sinus mucosa are not widely considered a reconstructive strategy, the use of fibrin glue for the treatment of post-operative CSF leak have been described ; additioNonetheless, further considerations would need a prospective analysis with the aim to analyze additional risk factors and to validate reconstructive strategies.The critical analysis of this series shows that IOL grade strongly affects POL rate. The type and the anatomical site of surgical approach should be considered during surgical planning in order to predict and assess IOL grade. No evidence of LD positioning effectiveness was found, even if it seems to be useful when IHFL was encountered. Once this aspect has been defined, tailored skull base reconstruction strategy should be chosen. Multilayer reconstruction with fat and NSF could reduce the rate of CSF leak in patients with IHFL, but the accuracy of different layers positioning and the capability to fill the empty dead space should be considered as the target. Surgical experience and skill play a role in lowering POL rate.S1 File(XLSX)Click here for additional data file.