Object The relentless natural progression of petroclival meningiomas mandates their treatment. The management of these tumors, however, is challenging. Among the issues debated are goals of treatment, outcomes, and quality of life, appropriate extent of surgical removal, the role of skull base approaches, and the efficacy of combined decompressive surgery and radiosurgery. The authors report on the outcome in a series of patients treated with the goal of total removal. Methods The authors conducted a retrospective analysis of 64 cases of petroclival meningiomas operated on by the senior author (O.A.) from 1988 to 2012, strictly defined as those originating medial to the fifth cranial nerve on the upper two-thirds of the clivus. The patients' average age was 49 years; the average tumor size (maximum diameter) was 35.48 ± 10.09 mm (with 59 tumors > 20 mm), and cavernous sinus extension was present in 39 patients. The mean duration of follow-up was 71.57 months (range 4–276 months). Results In 42 patients, the operative reports allowed the grading of resection. Grade I resection (tumor, dura, and bone) was achieved in 17 patients (40.4%); there was no recurrence in this group (p = 0.0045). Grade II (tumor, dura) was achieved in 15 patients (36%). There was a statistically significant difference in the rate of recurrence with respect to resection grade (Grades I and II vs other grades, p = 0.0052). In all patients, tumor removal was classified based on postoperative contrast-enhanced MRI, and gross-total resection (GTR) was considered to be achieved if there was no enhancement present; on this basis, GTR was achieved in 41 (64%) of 64 patients, with a significantly lower recurrence rate in these patients than in the group with residual enhancement (p = 0.00348). One patient died from pulmonary embolism after discharge. The mean Karnofsky Performance Status (KPS) score was 85.31 preoperatively (median 90) and improved on follow-up to 88, with 30 patients (47%) having an improved KPS score on follow-up. Three patients suffered a permanent deficit that significantly affected their KPS. Cerebrospinal fluid leak occurred in 8 patients (12.5%), with 2 of them requiring exploration. Eighty-nine percent of the patients had cranial nerve deficits on presentation; of the 54 patients with more than 2 months of follow-up, 21 (32.8%) had persisting cranial nerve deficits. The overall odds of permanent cranial nerve deficit of treated petroclival meningioma was 6.2%. There was no difference with respect to immediate postoperative cranial nerve deficit in patients who had GTR compared with those who had subtotal resection. Conclusions Total removal (Grade I or II resection) of petroclival meningiomas is achievable in 76.4% of cases and is facilitated by the use of skull base approaches, with good outcome and functional status. In cases in which circumstances prevent total removal, residual tumors can be followed until progression is evident, at which point further intervention can be planned.

N eurosurgical vascular cases often require complex microvascular bypass techniques, such as those used in operative corrections for moyamoya disease, 7,26,32 cerebral aneurysms, 9,13,14,19 and intracranial tumors. 30,31 Therefore, simple and accessible models for microvascular anastomosis training are increasingly essential for providing a means for refining and preserving skills. Several models, including chicken wings, 12,17 turkey wings, 1 rats, 15 human cadavers, 24,29 and plastic tubing, 22 have been proposed. However, these models are still less than ideal for various reasons, such as vessel diameter diversity, cost-effectiveness, artifacts due to storage (e.g., Low-flow and high-flow neurosurgical bypass and anastomosis training models using human and bovine placental vessels: a histological analysis and validation study obJective Microvascular anastomosis is a basic neurosurgical technique that should be mastered in the laboratory. Human and bovine placentas have been proposed as convenient surgical practice models; however, the histologic characteristics of these tissues have not been compared with human cerebral vessels, and the models have not been validated as simulation training models. In this study, the authors assessed the construct, face, and content validities of microvascular bypass simulation models that used human and bovine placental vessels. methods The characteristics of vessel segments from 30 human and 10 bovine placentas were assessed anatomically and histologically. Microvascular bypasses were performed on the placenta models according to a delineated training module by "trained" participants (10 practicing neurosurgeons and 7 residents with microsurgical experience) and "untrained" participants (10 medical students and 3 residents without experience). Anastomosis performance and impressions of the model were assessed using the Northwestern Objective Microanastomosis Assessment Tool (NOMAT) scale and a posttraining survey. results Human placental arteries were found to approximate the M 2 -M 4 cerebral and superficial temporal arteries, and bovine placental veins were found to approximate the internal carotid and radial arteries. The mean NOMAT performance score was 37.2 ± 7.0 in the untrained group versus 62.7 ± 6.1 in the trained group (p < 0.01; construct validity). A 50% probability of allocation to either group corresponded to 50 NOMAT points. In the posttraining survey, 16 of 17 of the trained participants (94%) scored the model's replication of real bypass surgery as high, and 16 of 17 (94%) scored the difficulty as "the same" (face validity). All participants, 30 of 30 (100%), answered positively to questions regarding the ability of the model to improve microsurgical technique (content validity). coNclusioNs Human placental arteries and bovine placental veins are convenient, anatomically relevant, and beneficial models for microneurosurgical training. Microanastomosis simulation using these models has high face, content, and construct validities. A NOMAT score of more than 5...

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