Efficiency and Safety of Autologous Fat Grafts in Reconstructing Skull Base Defects After Resection of Skull Base Meningiomas.

Reconstruction of the skull base after resection of skull base meningiomas is of paramount importance. Here we describe a safe and effective method of skull base reconstruction using autologous free fat grafts. In this retrospective analysis of patients operated for skull base meningioma from 2007 to 2014. We analyzed the surgical technique, efficiency and safety as well as the graft-related complications. Autologous free fat grafts were used in 55 patients, including 39 patients with posterior fossa meningiomas related to the petrous bone and 16 patients with anterior fossa meningiomas related to the paranasal sinuses. Three patients experienced postoperative cerebrospinal fluid (CSF) leak and were managed with temporary continuous lumbar drainage. One patient developed pneumocephalus and required revision. The occurrence of CSF leak was related to aggressive resection with resulting large skull base defects, especially in anterior skull base meningiomas. There were no donor site-related complications. The use of autologous free fat grafts is an effective and safe technique for reconstructing skull base defects after microsurgical resection of skull base meningiomas.

Metwali H ，Gerganov V ，Nery B ，Aly A ，Avila-Cervantes R ，Samii M ... -  《-》

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 The graft, withdrawn from the abdomen or thigh, was flattened and applied to the defect.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.

Bohoun CA ，Goto T ，Morisako H ，Nagahama A ，Tanoue Y ，Ohata K ... -  《-》

Significance of the simultaneous combined transcranial and endoscopic endonasal approach for prevention of postoperative CSF leak after surgery for lateral skull base meningioma.

Lateral skull base meningiomas, particularly sphenoorbital meningiomas, sometimes extend extremely widely into adjacent structures including the paranasal sinuses. For endonasal skull base reconstruction using a vascularized nasoseptal flap for prevention of postoperative cerebrospinal fluid (CSF) leak, the simultaneous combined transcranial and endoscopic endonasal approach was applied for resection of these extensive tumors. We performed a retrospective review of four patients treated with the simultaneous combined transcranial and endoscopic endonasal approach for resection of lateral skull base meningiomas. Preoperative characteristics, tumor extent, extent of resection, complications, and postoperative outcomes were analyzed. The tumor extended into the paranasal sinus, infratemporal fossa, and pterygopalatine fossa in all patients. Extracranial extension into the cavernous sinus or superior orbital fissure was detected in two and three patients, respectively. In one patient without extension into the cavernous sinus and superior orbital fissure, gross total resection was achieved, whereas in the other three patients, subtotal resection was performed, and small residual masses of the tumor remained in the cavernous sinus or superior orbital fissure to minimize the risk of postoperative ocular nerve damage. No patients experienced postoperative CSF leak. The simultaneous combined transcranial and endoscopic endonasal approach is useful for a subgroup of patients with lateral skull base meningiomas for prevention of postoperative CSF leak. Particularly in recurrent cases in which vascularized flaps from the transcranial side are likely unavailable due to prior tumor resection, this combined approach is worth considering depending on tumor extension into the paranasal sinus.

Matsuda M ，Akutsu H ，Tanaka S ，Ishikawa E ... -  《-》

Little Insights from Big Data: Cerebrospinal Fluid Leak After Skull Base Surgery and the Limitations of Database Research.

Cerebrospinal fluid (CSF) leak is a frustrating complication of skull base surgery. Published methodologies using national surgical databases to assess CSF leak have not accounted for variability between skull base operations. Our goal was to attempt the development of a novel framework for adapting big data techniques to skull base surgery and assess the reliability of corresponding data manipulations. A retrospective nested case-control analysis was performed using patients from the National Surgical Quality Improvement Program (NSQIP) registry, 2012-2015. Current Procedural Terminology and International Classification of Diseases, Ninth Revision codes identified possible skull base operations, which were systematically grouped by anatomic location. Meningioma, schwannoma, pituitary adenoma, and trigeminal neuralgia (TN) were included. Of 2918 patients, 84 (2.9%) were readmitted/reoperated on within 30 days for CSF leak. Operations involving the anterior fossa, both middle/posterior fossas in 1 approach, or the orbitocranial zygomatic approach were significantly associated with CSF leak, as were schwannomas and meningiomas in any location (8.5%, 3.1%, 10.2%, 4.1%, and 3.0%; all P < 0.0001). Multivariate analysis of only middle/posterior fossa lesions identified schwannoma (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.3-5.6; P = 0.008), TN (OR, 5.4; 95% CI, 2-14.7; P = 0.008), chronic obstructive pulmonary disease (OR, 3.9; 95% CI, 1.1-14; P = 0.03), and increased operative time (OR, 4.0; 95% CI, 1.7-9.5; P = 0.009) as significant CSF leak risk factors. Based on NSQIP data analyzed using a rational skull base/anatomic framework, risk factors for postoperative CSF leak include chronic obstructive pulmonary disease, operative time, anterior fossa meningioma, and middle/posterior fossa schwannoma or TN. Although databases such as NSQIP can be extensively manipulated to generate surrogate results that may provide limited insight, applications beyond their design should be approached carefully.

Perry A ，Kerezoudis P ，Graffeo CS ，Carlstrom LP ，Peris-Celda M ，Meyer FB ，Bydon M ，Link MJ ... -  《-》

Sequelae of autologous fat graft used for reconstruction in skull base surgery.

The use of an autologous free fat graft is a widely applied technique to obliterate dead space and reinforce dural closure during skull base reconstructions. The associated complications and outcomes of this practice have not been studied. Dissemination of fat in the subarachnoid space resulting in lipoid meningitis has been reported after translabyrinthine approaches, and leakage of liquefied fat is seldom reported in the literature. This study aims to evaluate the morbidity associated with the usage of autologous fat graft in reconstruction of skull base defects based on an extensive experience. This study is a retrospective review of 1581 cases in which the senior author (O.A.) used a skull base approach for the resection of tumor. Autologous fat grafts were used for reconstruction in 974 cases and 10 cases (male to female ratio, 4:6) in which there were associated complications were analyzed. Complications included leakage of sterile liquefied fat from fistula (patients 1, 2, 3), delayed cerebrospinal fluid leak after radiation (Patients 5, 6, 9), and postoperative lipoid meningitis (Patients 4, 7, 8, 10). The onset ranged from 11 days to 10 years. Four patients were managed conservatively, and the other six required surgical intervention. All patients had good outcomes after treatment. The use of autologous fat is associated with a 1% complication rate and should be considered a safe and effective method for skull base reconstruction. However, neurosurgeons should be aware of early and late complications of fat necrosis, including sterile liquefied fat fistula, cerebrospinal fluid leakage, and lipoid meningitis.

Taha AN ，Almefty R ，Pravdenkova S ，Al-Mefty O ... -  《-》