Tag: petrosal

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Arteriovenous malformations in the cerebellopontine angle: assessment of the “backdoor resection” technique and microsurgical results in 38 patients

J Neurosurg 141:1198–1211, 2024

Posterior fossa arteriovenous malformations (AVMs) represent 7% to 15% of all intracranial AVMs and are associated with an increased risk of hemorrhage, morbidity, and mortality compared with supratentorial AVMs, thus prompting urgent and definitive treatment. Cerebellopontine angle (CPA) AVMs are a unique group of posterior fossa AVMs incorporating characteristics of brainstem and cerebellar lesions, which are particularly amenable to microsurgical resection. This study reports the clinical, radiological, operative, and outcome features of patients with CPA AVMs in a large cohort.

METHODS The authors conducted a single-surgeon, 2-institution retrospective cohort study of all consecutive patients with CPA AVMs treated with microsurgical resection during a 25-year period.

RESULTS CPA AVMs represented 22% (38 of 176) of all infratentorial AVMs resected by the senior author. Overall, 38 patients (22 [58%] male and 16 [42%] female) met the study inclusion criteria and were analyzed. Most patients presented with hemorrhage (n = 29, 76%). The median age at surgery was 56 (range 6–82) years. Subtypes included 22 (58%) petrosal cerebellar AVMs, 11 (29%) lateral pontine AVMs, and 5 (13%) AVMs involving both the brainstem and cerebellum. Most AVM niduses were small (< 3 cm; n = 35, 92%) and compact (n = 31, 82%). Fourteen (37%) patients harbored flow-related aneurysms. Twenty (53%) patients underwent preoperative embolization. Complete angiographic obliteration was achieved with microsurgery in 35 (92%) patients. Five (13%) patients with poor neurological conditions at presentation died before hospital discharge. Of the 7 (18%) patients with new postoperative neurological deficits, 5 had transient deficits. The median (interquartile range) follow-up was 1.7 (0.5–3.2) years; 32 (84%) patients were alive at last follow-up, and 30 (79%) had achieved a favorable neurological outcome (modified Rankin Scale [mRS] score 0–2). The only independent predictor of unfavorable postoperative outcome (mRS score 3–6) was the preoperative mRS score (p = 0.002).

CONCLUSIONS CPA AVMs are unique posterior fossa lesions, including petrosal cerebellar and lateral pontine AVMs. The “backdoor resection” technique provides a safe and efficient strategy with high obliteration rates and a low risk of treatment-related morbidity. Microsurgical resection should be considered the frontline treatment for most CPA AVMs, except for those with a significant diffuse brainstem component.

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True petroclival meningiomas

True petroclival meningiomas- results of surgical management

J Neurosurg 120:40–51, 2014

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.

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