Extended Anterior Petrosectomy Through the Transcranial Middle Fossa Approach and Extended Endoscopic Transsphenoidal-Transclival Approach: Qualitative and Quantitative Anatomic Analysis.

BACKGROUND: Petroclival tumors and ventrolateral lesions of the pons present unique surgical challenges. This cadaveric study provides qualitative and quantitative anatomic comparison for an anterior petrous apicectomy through the transcranial middle fossa (TMF) and expanded endoscopic transsphenoidal-transclival approaches. METHODS: In 10 silicone-injected heads, the petrous apex and clivus were drilled extradurally using middle fossa and endonasal approaches. With in situ and frameless stereotactic navigation, we defined consistent points to compare working areas, bone removal volumes, approach angles, and surgical freedom. RESULTS: Mean exposed TMF area (21.03 ± 3.46 cm2) achieved a 44.71 ± 4.13° working angle to the brainstem between cranial nerves V and VI. Kawase's rhomboid area measured 1.76 ± 0.34 cm2, and bone removal averaged 1.20 ± 0.12 cm3 at the petrous apex. Surgical freedom on the lateral brainstem was higher halfway between cranial nerves V and VI at the center of the rhomboid compared with midline at the basilar sulcus (P < 0.01). After clivectomy and petrous apicectomy, mean exposed expanded endoscopic transsphenoidal-transclival area was 5.29 ± 0.66 cm2. Approach from either nostril showed no statistically significant differences in surgical freedom at the foramen lacerum and midpoint basilar sulcus. At the petrous apex, bone volume removed and area exposed were significantly larger for the TMF approach (P < 0.001). CONCLUSIONS: Expanded transclival anterior petrosectomy through the TMF approach provides an adequate corridor to lesions in the upper ventrolateral pons. The expanded endoscopic transsphenoidal-transclival approach better fits midline lesions not extending laterally beyond cranial nerve VI and C3 carotid when evaluating normal anatomic parameters.

Long-term follow-up after surgical removal of meningioma of the inner third of the sphenoidal wing: outcome determinants and different strategies.

Meningioma arising in the inner third of the sphenoidal wing has been well recognized since the origin of neurosurgery, yet it still poses a formidable challenge for the surgeon. Treatment strategies can be optimized through a tailored approach to surgical timing and use of a non-surgical armamentarium. The aim of this study was to evaluate the long-term effect of different strategies on progression-free survival and overall survival. We examined the clinical records of brain tumor patients to assess determinants for surgery (extent of tumor removal, postoperative complications) and for progression-free survival and overall survival in relation to timing of surgery eventually followed by stereotactic radiosurgery (SRS). The records of 60 patients were retrospectively reviewed, from preoperative assessment to a median follow-up of 104 months. All were symptomatic with prevalently visual symptoms (42.2%), large tumors (median diameter 3.44 cm), extension into the cavernous sinus (38.3%), and severe vascular involvement of one or more encased or narrowed vessels (50%). Subtotal removal was achieved in 40% of cases, mainly determined by cavernous sinus and vascular involvement; neurological complications occurred in 18.3% (persistent in 6.7% due to oculomotor and vascular injury). The overall rate of symptom improvement was 32.3% at 3 months and 49.5% at 12 months. Radiological monitoring prevented clinical progression; tumor progression occurred in 11.7% of cases. There were significant differences in progression-free survival between patients with (median 46 months) and those without (median 104 months) recurrence (p = 0.002): 12.5% after total removal, 6.2% after subtotal removal and adjuvant SRS, and 28.5% after subtotal removal and observation. The related Kaplan-Meier survival curve showed no significant difference between the three strategies. Further, disease progression after recurrence was noted in 28.6% of cases, but overall survival was not influenced by either tumor recurrence or type of treatment. Treatment failure was recorded in four cases (6.7%): one perioperative death and three later on. Surgery is the mainstay for the treatment of symptomatic meningioma and to restore neurological function; however, resectability is limited by vascular and cavernous sinus involvement. Careful postoperative monitoring prevented clinical progression and adjuvant or adjunctive SRS proved effective in tumor control. A low surgical complication rate and excellent long-term outcomes were achieved with this strategy.

Surgical Management of Medial Tentorial Meningioma: Falcotentorial and Torcular.

BACKGROUND: Falcotentorial meningiomas (FTM) stand out for their rarity, inconsistent definition, and surgical complexity. It is appropriate to deal with them in the context of medial tentorial meningiomas (TMs). METHODS: Clinical and radiologic characteristics of medial TMs, comprising the typical features of FTM and TM, along with surgical management and short-term and long-term outcomes, are reported. RESULTS: FTM (n = 16) were typically supratentorial, large, edematous tumors that caused mainly headache and hemianopia; TM (n = 12) were infratentorial, smaller not edematous tumors that caused mainly headache and gait ataxia. The most frequent venous pattern was straight sinus infiltration in one third of cases of FTM and occlusion in one half of cases of TM. Total removal (Simpson grade I-II) was obtained in 46.4% of cases and subtotal removal (Simpson grade III-IV) in 53.6%. Suprainfratentorial extension in FTM and incomplete venous invasion in TM were the factors most likely opposing complete removal. The overall acute complications rate was 32.1% (higher for FTM), transient for most cases. Patients with supratentorial meningiomas performed significantly worse preoperatively (Karnofsky Performance Status ≤70 in 75% of cases); patients with infratentorial symptoms/signs recovered worse postoperatively. Stereotactic radiosurgery with subtotal removal was used as adjuvant treatment in 8 cases. Only 2 recurrences, both atypical tumors, occurred at 57.6 months (mean) follow-up. CONCLUSIONS: As a general rule, careful venous management, tailored surgical approach for FTM, and cautious tumor removal for TM can yield good and stable results. Total removal accounts for half the cases in both groups, whereas FTM was associated with worse postoperative complications.

Interhemispheric approach to tumors of the posterior gyrus cinguli.

OBJECTIVE: Posterior gyrus cinguli tumors are a well-defined group of tumors that pose considerable challenges in creating surgical access and manipulating adjacent eloquent areas (visual and motor). Here we report our 5-year experience in the surgical treatment of these tumors and describe tumor characteristics, surgical steps, critical aspects, and prognostic factors. METHODS: This series comprises 37 patients operated on for glioma (high-grade in 28, low-grade in 9), often presenting with motor impairment (n=20), intracranial hypertension (n=15), seizures (n=11), and/or hemianopia (n=9). Preoperative assessment was performed with magnetic resonance imaging. Half of the tumors were more than 4 cm in size, and the majority presented secondary extension into the fronto-parieto-occipital area, the temporo-mesial area, and/or the corpus callosum. Positioning and assisted surgery were optimized in each patient based on preoperative planning. RESULTS: The ipsilateral interhemispheric approach was elected in all cases. Tumor size and extension were significantly associated with the degree of tumor removal. Total removal was achieved in 25 patients (65%); 4 (10%) had persistent morbidity (visual or motor deficits). The occurrence of local and systemic complications was negligible. CONCLUSIONS: Surgical treatment of posterior gyrus cinguli tumors can be safely approached via the interhemispheric route as it permits several beneficial operative maneuvers in selected cases.