Dural Defect Research Articles

Management Strategies of Cranial Encephaloceles: A Neurosurgical Challenge.

Background:Encephalocele is defined as herniation of cranial contents beyond the normal confines of the skull through a defect in the calvarium either along the midline or at the base of skull. These anomalies should be repaired in the first few months of life to prevent neurological deficits and facial disfigurement. The aim of the surgery is water tight dural closure at the level of internal defect, closure of skull defect, and reconstruction of external bony deformity.Materials and Methods:Fifty-four cases of encephalocoeles were studied in our hospital over a 6-year period from 2010 to 2016. Computed tomography (CT) and magnetic resonance imaging (MRI) brain were performed to delineate the bony defect and associated anomalies. Reconstruction of the bony defect was done using autologous calvarial bone graft, Osteopore polycaprolactone (PCL) bone scaffold filler and titanium mesh.Results:In our study, 54 patients (34 boys and 20 girls) whose age varied between 2 months and 14 years were evaluated. Frontoethmoidal (44.5%) and occipital encephaloceles (25.9%) were the most frequently seen varieties. Repair of the dural defect either primarily or using pericranium was done in all cases. Closure of the bony defect was done using autologous calvarial bone graft in 12 (22.22%) patients. Titanium mesh was used in eight and Osteopore PCL bone scaffold filler in four children. Cranioplasty was not done in remaining thirty children because of the small bone defect. Overall, 80% had no postoperative problem and were discharged between 7 and 10 days of surgery. Cerebrospinal fluid leak was the most frequent postoperative complication, noted in five patients. Re-exploration with repair was done in one and remaining four were managed conservatively. Overall, cosmetic results were acceptably good, with parents judging the cosmetic outcome as good to excellent in 70%, satisfactory in 18%, and poor in 3% at the last follow-up.Conclusion:Our study demonstrated that encephaloceles are associated with complex deformities and pose a technical challenge to the neurosurgeon. A multidisciplinary approach is necessary to manage these cases. MRI brain and three dimensional CT aids in evaluating the deformity better and surgical correction should be performed as soon as possible to prevent a further neurological deficit. Repair of dural defect and reconstruction of the skull defect results in a good long-term outcome. We present our experience on 54 cases of cranial encephaloceles managed surgically over a period of only 6 years which is one of the largest series reported from Asia.

Simplified Dural Reconstruction Procedure Using Biocompatible Polyglycolic Acid Felt with Autologous Abdominal Fat Grafts after a Transpetrosal Approach

Dural reconstruction after transpetrosal approaches is complicated because complete primary closure of presigmoid dura mater is difficult to achieve. To address this problem, we use biocompatible polyglycolic acid (PGA) felt (Durawave) to reconstruct dural defects. To evaluate the use of PGA felt in dural reconstruction, we compared these results with those after conventional duraplasty using autologous fascia grafts. We retrospectively surveyed all cases involving a transpetrosal approach reported since 2013. In the conventional procedure, autologous fascia was fixed over the dural defect using stay sutures; any remaining dead space was obliterated by placing abdominal fat grafts. Since April 2017, we have used PGA felt instead of fascia. Of the 37 cases identified, 27 were reconstructed according to the conventional procedure, and the remaining 10 cases were reconstructed using PGA felt. Among the 27 conventional cases, 8 involved cerebrospinal fluid (CSF)-related complications, including 3 cases of rhinorrhea and 5 cases of subcutaneous fluid collection, and 2 cases (7%) required repair surgery. Of the 10 cases involving PGA felt, 1 case (10%) involved subcutaneous fluid collection and required repair surgery, and whereas the remaining 9 cases had no evidence of CSF leakage. In addition, the median dural reconstruction time using PGA felt was 9 minutes, significantly shorter than that when autologous fascia was used (median, 44 minutes). Using PGA felt for presigmoid dura simplifies dural reconstruction because it obviates the need to suture in a deep field. PGA felt has the potential to prevent CSF-related complications after transpetrosal approaches.

Augmentation of Dural Defect Repairs Strength With an Acrylic Plate in a Porcine Ex Vivo Model

Background Large skull base defects can be challenging to repair. This study uses a controlled ex vivo model to examine the failure pressures of various dural repairs of large skull base defects using mucosa with fibrin glue under 3 conditions: No Additional Support of the repair, support with a Foley catheter (Direct Support), and with Foley catheter contact over a rigid acrylic plate (Diffuse Support). Methods Failure pressures of dural repairs with and without support were determined in a porcine model using an ex vivo closed testing apparatus. In addition, 20 mm × 15 mm dural defects were created. Skull base repairs were performed using porcine dura as an underlay graft followed by a septal mucosa overlay. Saline was infused at 30 mL/h, applying even force to the underside of the graft until repair failure occurred for each condition (none, direct, and diffuse support). Five trials were performed per repair type for a total of 15 repairs. Results The mean failure pressures were as follows: No Additional Support, 6.494 ± 2.553 mm Hg; Direct Support, 5.103 ± 3.913 mm Hg; and Diffuse Support, 15.649 ± 2.638 mm Hg. A post hoc Bonferroni-Holm test demonstrated significant difference between No Additional Support and Diffuse Support ( P = .001), as well as Direct Support and Diffuse Support ( P = .002). Conclusion Support of dural repairs in this model withstood higher pressures when the Foley catheter’s support is distributed evenly using a flat acrylic plate. Use of this plate is the only repair tested in this model that tolerated normal adult supine intracranial pressures.

Novel Strategy of Ventral Dural Repair for Idiopathic Thoracic Spinal Cord Herniation: Report of Outcomes and Review of Techniques.

Idiopathic ventral thoracic spinal cord herniation is a rare condition that usually presents with progressive myelopathy or Brown-Séquard syndrome. More than 100 cases have been reported with significant variance in surgical treatment strategies and likewise, significant variance in patient outcomes. Although laminectomy has often been used, to date, there is no consensus regarding the optimal surgical approach or strategy for ventral dural repair. To report and illustrate a novel approach to repair the ventral dural defect with more than 2 yr of clinical follow-up. The specific approach and graft used are both detailed. A retrospective chart review of all known cases of idiopathic spinal cord herniation at the Cleveland Clinic over the last 15 yr was performed. Postoperative outcome scores (including the Japanese Orthopedic Association score, European Myelopathy score, and Nurick) were calculated preoperatively and postoperatively. A total of 5 patients were identified. Four of five patients improved clinically after surgery and 1 patient remained unchanged at last follow-up (average 23.2 mo, range 12-60 mo). There were no complications. All patients had postoperative magnetic resonance imaging demonstrating realignment of the spinal cord and no recurrence of tethering. A unilateral dorsolateral, transpedicular approach combined with laminectomy provides excellent exposure for ventral or ventrolateral dural defects associated with idiopathic spinal cord herniation and minimizes spinal cord manipulation. A collagen matrix graft used as an onlay between the spinal cord and ventral dural defect is a safe and effective option for ventral dural repair.

Identification of a Dural Defect with Cine Phase Contrast MR Imaging.

Identification of a Dural Defect with Cine Phase Contrast MR Imaging.

Histopathological Investigation of the Effectiveness of Collagen Matrix in the Repair of Experimental Spinal Dura Mater Defects.

This study investigated the suitability of the collagen matrix as a dural graft in the repair of experimental spinal dura mater defects. In the study, 30 New Zealand white rabbits were used. The rabbits were divided into a study and control group. In both groups, following exact laminectomy (Th 10 and 11) in rabbits under the isoflorane anesthesia, a spinal dural defect 1×0.5 cm in size was formed. In the study group, the dura mater defect was covered with collagen matrix; in the control group, the excised dura was sutured back to its original position. At the end of the follow-up period, the rabbits were sacrificed. In all subjects, the vertebral colon was excised completely, and it was fixed in 10% formaldehyde solution. Sections 3 pm thick were taken from the specimens, stained with hematoxylin and eosin, and examined under a light microscope. The stained sections were evaluated under light microscopy with regard to the cellular inflammatory response, fibroblastic proliferation, foreign body reaction, and capsule formation. The collagen matrix was completely absorbed, and it was easy to use since it did not require sutures. Foreign body reactions were minimal in the early period and were resolved entirely in the end. Inflammatory response against the collagen matrix was no greater than in the control group in which the dura was sutured primarily and then closed, eventually disappearing entirely, and no adhesion formation resulted. Collagen permits successful regeneration by combining with the dura mater. No capsule formation was observed in either group. This study shows that collagen is suitable for duraplastic procedures and that it may be a useful agent in patients in whom the dura cannot be closed primarily due to retraction, constriction, or excision.

A Stable Large Animal Model for Dural Defect Repair with Biomaterials and Regenerative Medicine.

Using biomaterials and regenerative medicine to repair tissue defects has been a very hot research field, during which the development of stable large animal models with appropriate biotechnology is crucial. Recently, more and more researchers are paying attention to dural defect repair. However, the lack of widely recognized stable large animal models has seriously affected the related further research. In this study, a stable large animal dural defect model is developed exactly for the first time. Therefore, the article would attract considerable attention and be highly cited after publication.

Posterior Approach and Spinal Cord Release for 360° Repair of Dural Defects in Spontaneous Intracranial Hypotension.

Spinal cerebrospinal fluid (CSF) leaks are the cause of spontaneous intracranial hypotension (SIH). To propose a surgical strategy, stratified according to anatomic location of the leak, for sealing all CSF leaks around the 360° circumference of the dura through a single tailored posterior approach. All consecutive SIH patients undergoing spinal surgery were included. The anatomic site of the leak was exactly localized. We used a tailored hemilaminotomy and intraoperative neurophysiological monitoring (IOM) for all cases. Neurological status was assessed before and up to 90 d after surgery. Forty-seven SIH patients had an identified CSF leak between the levels C6 and L1. Leaks, anterior to the spinal cord, were approached by a transdural trajectory (n=28). Leaks lateral to the spinal cord by a direct extradural trajectory (n=17) and foraminal leaks by a foraminal microsurgical trajectory (n=2). The transdural trajectory necessitated cutting the dentate ligament accompanied by elevation and rotation of the spinal cord under continuous neuromonitoring (spinal cord release maneuver, SCRM). Four patients had transient defiticts, none had permanent neurological deficits. We propose an anatomic classification of CSF leaks into I ventral (77%, anterior dural sac), II lateral (19%, including nerve root exit, lateral, and dorsal dural sac), and III foraminal (4%). Safe sealing (with IOM) of all CSF leaks around the 360° surface of the dura is feasible through a single posterior approach. The exact surgical trajectory is selected according to the anatomic category of the leak.

Radical Intracapsular Dissection Technique for Dumbbell-Shaped Spinal Schwannoma with Intradural and Extradural Components

Dumbbell-shaped spinal schwannomas with intradural and extradural components are associated with higher complication rates. This may be in part due to epineurial dissection of the extradural component, which inevitably damages the functioning nerve fibers beneath the epineurium and may lead to dural defects that are often difficult to repair. The objective was to describe a radical intracapsular dissection technique that provides a simpler operative field with no need for dural repair and a better chance of preserving functioning nerve fibers. The technique comprised the following: 1) exposure of the tumor while preserving spinal stability; 2) a single incision encompassing the dura and epineurium; 3) microsurgical dissection of the tumor just beneath the epineurium, preserving the viable nerve fibers; and 4) primary closure of the duroepineurial incision. We describe a case series of 7 patients in whom this type of tumor was excised using this technique. Gross total excision was achieved in 5 patients. In 1 patient with a large paravertebral component, the remaining tumor was removed with an additional anterior approach. No cerebrospinal fluid leak was noted, and no recurrence was observed in the median follow-up period of 36 months. The radical intracapsular dissection technique described herein represents an alternative technique for the removal of dumbbell-shaped spinal schwannomas with intradural and extradural components.

Treating nasoethmoidal encephalocele in a low-resource country: a surgical experience from a Philippine multidisciplinary craniofacial team.

It was described that nasoethmoidal encephalocele repair in the Philippines has been limited by insufficient resources, financial constraints, and a lack of surgical expertise. The purpose of this study was to report initial results and complications of Philippine patients with nasoethmoidal encephalocele surgically managed with an approach adapted to an environment with limited financial resources. All patients (n = 21) with nasoethmoidal encephalocele who underwent intracranial and extracranial repairs (frontal wedge osteotomy to access the encephalocele cyst and cranial base defect, dural defect repair, split frontal grafts fixed with polydioxanone sutures to reconstruct the cranial defect and nasal dorsum, and medial canthopexy) from January 2015 to May 2017 were included. The correlations between sizes of masses and cranial defects with the occurrence of complications were tested. The surgical results were classified based on a previously published outcome grading scales I-IV on the need for additional surgery. Nineteen patients (90.5%) had unremarkable post-operative course. Two patients (9.5%) presented with complications (cerebrospinal fluid leak and surgical site infection) which were successfully managed with no additional surgery. The sizes of masses and cranial defects were not correlated (p > 0.05) with complications. The overall rate of surgical results ranked according to the need for additional surgery was 2.4 ± 0.5 (between categories II and III). We reported successful surgical repair of nasoethmoidal encephaloceles in Philippine patients by a local multidisciplinary craniofacial team.

The Helmet-Visor Pericranial Flap as a Viable Option for Anterior Cranial Base Reconstruction in Complex Oncologic Cases

To describe a novel bilaterally pedicled pericranial flap for anterior cranial base reconstruction after removal of complex frontobasal cancers extending to the frontal region, thus precluding the use of standard reconstructive techniques. In selected oncologic cranial base surgeries, the use of the standard galea frontalis pericranial flap for reconstructive purposes may be precluded by tumor infiltration. In such cases, dura mater reconstruction and exclusion of frontal sinuses from the intracranial space can be performed using a large superficial temporal artery bilaterally pedicled pericranial flap obtained from both temporoparietal regions. Surgical technique, indication, contraindication, complications, and degree of resection are recorded to evaluate the efficacy of this surgical method. A 48-year-old man affected by a recurrence of frontobasal squamous cell carcinoma was surgically treated by combined transcranial and endoscopic endonasal resection. A large pericranial flap pedicled bilaterally on the parietal branches of the superficial temporal artery was obtained, transposed anteriorly, carefully watertight sutured to the dural defect, and used to exclude cranialized frontal sinuses as well. The reconstruction was successful, and the patient was discharged home on the tenth postoperative day without any complications and/or development of cerebrospinal fluid leak. Contrast-enhanced magnetic resonance imaging 3 months after surgery was clear from disease with consolidated surgical outcomes. This novel pericranial flap seems to be easily obtained and effective for anterior cranial base reconstruction when the use of a traditional galea frontalis flap is precluded for oncologic reasons and there are concerns for the possible development of contaminations and cerebrospinal fluid leaks.

Localized controlled fibrin glue application with gelatin sponge for hemostasis and dural defect repair: Technical note

ObjectivesHemostasis and dural defect repair are fundamental aspects of neurosurgical procedures. Some significant bleeding may be caused by dural tears (e.g. bleeding from cerebral dural venous sinuses). Various methods have been previously reported for these purposes, utilizing commercially available surgical materials such as gelatin sponge and fibrin glue. We describe a simple, yet versatile and flexible technique with a critical modification to the previously known combined use of gelatin sponge and fibrin glue. We then present a few illustrative cases and discuss the utility and advantages of the described technique. Patients and methodsThe described technique involves separate and sequential application of fibrinogen solution followed by thrombin solution of fibrin glue over gelatin sponge, which enables hemostasis or dural defect repair in a localized, controlled manner. ResultsWe have utilized this technique effectively for hemostasis and dural defect repair in a variety of neurosurgical procedures for over 10 years. We have found the technique to be highly useful and effective, although the effectiveness of this technique may be difficult to quantify objectively and independently of the other standard surgical maneuvers, given that hemostasis and prevention of cerebrospinal fluid leak is multifactorial. We have not encountered any complications specifically attributable to the use of fibrin glue and/or gelatin sponge for this technique. ConclusionThis technique will add to the neurosurgeons' arsenal for hemostasis and dural defect repair, in addition to the more standard and basic surgical maneuvers.

U-shaped Dural Flap: A Simple Method for Transcranial Skull Base Defect Repair-Technical Report.

Accidental anterior skull base defects associated with surgery are difficult to treat. There are several methods for the repair, yet postoperative rhinorrhea can occur despite the closure. A 56-year-old female patient was admitted for the treatment of a paraclinoid internal carotid artery aneurysm. The surgery included removal of the anterior clinoid process, unroofing the optic canal, decompressing the optic nerve, and clipping the aneurysm. During the surgery, the planum sphenoidale was accidentally drilled and the nasal cavity exposed. The dural defect was repaired using a U-flap technique. No postoperative cerebrospinal fluid (CSF) rhinorrhea occurred in the patient, and she was discharged on postoperative day 3. On follow-up examination the patient did not have evidence of CSF leakage.

Cerebrospinal fluid leaks after spine tumor resection: avoidance, recognition and management.

Post-operative CSF leaks are a known complication of spine surgery in general, and patients undergoing surgical intervention for spinal tumors may be particularly predisposed due to the presence of intradural tumor and a number of other factors. Post-operative CSF leaks increase morbidity, lengthen hospital stays, prolong immobilization and subject patients to a number of associated complications. Intraoperative identification of unintended durotomies and effective primary repair of dural defects is an important first step in the prevention of post-operative CSF leaks, but in patients who develop post-operative pseudomeningoceles, durocutaneous fistulae or other CSF-leak-related sequelae, early recognition and secondary intervention are paramount to preventing further CSF-leak-related complications and achieving the best patient outcomes possible. In this article, the incidence, risk factors and complications of CSF leaks after spine tumor surgery are reviewed, with an emphasis on avoidance of post-operative CSF leaks, early post-operative identification and effective secondary intervention.

Combined Petrosal Approach for Resection of Petroclival Meningioma with Endoscopic Assistance: Operative Video and Technical Nuances.

Petroclival meningiomas are formidable lesions due to their deep location in the skull base and proximity to critical neurovascular structures. The combined petrosal approach, comprised of an anterior petrosectomy and posterior retrolabyrinthine petrosectomy, allows for both supra- and infratentorial exposure of the tumor in the petroclival region while potentially preserving hearing function ( Fig. 1 ). In this operative video atlas manuscript, the authors demonstrate a step-by-step technique for microsurgical resection of a petroclival meningioma via the combined petrosal approach. The nuances of microsurgical and skull base technique are illustrated including drilling of the petrous bone, transecting the tentorium, resection of the tumor, and multilayered reconstruction of the dural defect. The combined petrosal approach allows for multiple angles of attack including both subtemporal and presigmoid corridors. In summary, the combined petrosal approach with endoscopic assistance is an important strategy in the armamentarium for surgical resection of petroclival meningiomas ( Fig. 2 ). The link to the video can be found at: https://youtu.be/ipZb9kHcP2g .

Neurosurgical management of Currarino syndrome: A case series and review of literature.

Background:The Currarino syndrome (CS), defined by the triad of anorectal malformations, sacral bone deformities, and presacral masses, is rare. There are few surgical series that discuss conservative management versus the surgical approaches to these lesions. Here, we describe utilizing a combined anterior and posterior approach for resecting these lesions in four patients.Methods:Four patients with CS were treated with two-stage approaches performed by a multidisciplinary team, including pediatric neurosurgery and general surgery. The first anterior laparoscopic approach mobilized the presacral mass from its ventral attachments. The second posterior procedure detethered the spinal cord, repaired the dural defect, and facilitated removal of the presacral mass.Results:Gross total resection of all four presacral masses was accomplished without intraoperative complication; all patients clinically improved.Conclusion:The CS is characterized by a large presacral mass. Here, one must rule out malignancy and also consider diagnosis/resection due to the risks for malignant transformation. The operative approach we described in four patients utilized standard anterior mobilization of the mass, followed by posterior detethering, dural repair, and ultimate resection.

Lumbar laminotomy for the intrathecal administration of nusinersen for spinal muscular atrophy: technical note and outcomes.

Nusinersen (Spinraza) is a US Food and Drug Administration-approved intrathecal medication for the treatment of spinal muscular atrophy (SMA). Adult patients with SMA often undergo thoracolumbar fusion to treat neurogenic scoliosis, preventing thecal access. The authors report a laminotomy technique and the ease of intrathecal access in three SMA patients with prior thoracolumbar fusions.Patients were positioned in the lateral decubitus position or prone. Lumbar laminotomy was performed below the conus, between the lateral longitudinal rods, to preserve mechanical stability. Fluoroscopy provided real-time identification of instruments. Hardware was contoured with a carbide drill bit to develop the surgical window. Fiducial screws were placed along the perimeter for demarcation. Sublaminar wire removal caused dural defects that were repaired with a layer of dural substitute onlay and sealant. All patients successfully received nusinersen thecal injections via lumbar puncture by an interventional radiologist. Fluoroscopy time ranged from 6 to 36 seconds. No postoperative pseudomeningoceles, cerebrospinal fluid leaks, or wound complications occurred.For patients with SMA and posterior fusion from prior scoliosis treatment, lumbar laminotomy is an effective method for creating thecal access for the administration of nusinersen.

Skull Base Dural Repair Using Autologous Fat as a Dural Substitute: An Efficient Technique

Dural repair during skull base approaches remains challenging, especially in the presence of significant defects. The autologous fat has become an alternative to various substitute materials being used previously. We report here our experience and technique for the repair of notable skull base dural defects using autologous fat as a dural substitute. Over a period of 5 years, 71 consecutive patients operated on for skull base pathologies with an important intraoperative dural defect repaired using autologous fat tissue as replacement material were reviewed. The graft, withdrawn from the abdomen or thigh, was flattened and applied to the defect. The clinical findings and outcomes were assessed. Main pathologies included schwannomas (45%) and meningiomas (35.21%), with no side predilection. Surgical approaches such as transcondylar fossa, suboccipital, and frontotemporal approaches were used. Dural defects were mainly located in the posterior (73.2%) and middle cranial fossae (25.4%). No harvesting site-related complication occurred. In 7 cases, transitory subcutaneous fluid collection spontaneously resorbing after 8 days to 2 months was observed. No external cerebrospinal fluid leakage, infection, or other complication was noted during the following period. Dural repair can be effectively and durably achieved using autologous fat graft as a dural substitute during skull base approaches, even in cases of extended defects. The observed characteristics of the fat graft along with the achieved outcome make it an ideal dural substitute.

Operative Management of Idiopathic Spinal Cord Herniation: Case Series and Novel Technique for Repair of Recurrent Herniation

Idiopathic spinal cord herniation (ISCH) is a rare pathology of the spine defined by herniation of the spinal cord through a dural defect. To highlight the operative management of ISCH and the surgical nuances of ISCH repairs conducted at our institution. This retrospective review examines consecutive patients with ISCH who were treated surgically between January 1, 2010, and July 31, 2017, at Barrow Neurological Institute, Phoenix, Arizona. Four patients with ISCH presented with thoracic myelopathy and lower extremity weakness during the study period. Treatment consisted of reduction of the herniated spinal cord and filling of the dural defect with a collagen-based dural regeneration matrix. In 3 patients the dural edges were covered with a collagen-matrix intradural sling, and in 1 patient they were repaired primarily with interrupted sutures. Three of the 4 patients experienced improvement in myelopathic symptoms; the fourth patient suffered neurological decline in the immediate postoperative period. ISCH is a complex pathological condition likely to result in progressive myelopathy. Surgery offers patients the possibility of stabilizing the progression of the spinal cord dysfunction and perhaps restoring neurological function. However, extreme care must be taken during surgery to minimize manipulation of the fragile herniated cord.

The efficacy of an endoscopic endonasal approach in the repair of cerebrospinal fluid fistula: a clinical analysis

<p class="abstract"><strong>Background:</strong> Cerebrospinal fluid (CSF) fistula is an abnormal CSF leakage due to bone and/or dural defect of the skull base and usually operated with endonasal endoscopic approach. The aim of this study was to determine the efficacy of an endonasal endoscopic approach in the repair of CSF leakage and to find the reasons of the recurrence of endoscopic procedure.</p><p class="abstract"><strong>Methods:</strong> The medical records of 24 patients that presented with the diagnosis of cerebrospinal fluid fistula and who had undergone endonasal endoscopic repair surgery were reviewed retrospectively. </p><p class="abstract"><strong>Results:</strong> 13 patients (54.2%) were found to have spontaneous CSF fistulas without any history of trauma, while 11 patients (45.8%) had posttraumatic CSF fistulas. The mean body mass index (BMI) of patients was 31. 3 kg/m² (20.1-49.6). Nasal septal cartilage was used as a graft material in 19 patients (79%) while only fascia was used in 5 patients (21%). The evaluation of long-term results revealed recurrence in 4 patients (16.6%). Two of these patients required a second surgical repair.</p><p class="abstract"><strong>Conclusions:</strong> An endoscopic endonasal approach is a safe method with less morbidity and a reliable outcome in the repair of CSF fistulas. The most important causative factors in the recurrence of endoscopic repair of CSF leak might be to have high BMI and not to use multilayered graft material for closure of fistula.</p><p class="abstract"> </p>