Intracranial cavernous malformation surgery
Goal of surgery: complete removal of the malformation. Since CMs are not particularly bloody, piecemeal excision is an option; especially important in brainstem lesions.
Stereotactic localization or intraoperative ultrasound may be particularly helpful in localizing. When operating on CMs that have bled, one usually encounters a cavity containing the CM and blood degradation products 4).
Initial dissection is directed at separating the lesion from the adjacent brain. Although bleeding is usually not a problem, it occasionally may be brisk if the CM is entered before the dissection and devascularization is complete. Once the dissection is complete, the contents of the CM capsule may be removed piecemeal to minimize the parenchymal opening (especially important in the brainstem). For supratentorial CMs presenting with seizures, it is desirable to also remove the hemosiderin-stained brain immediately surrounding the CM. Keep in mind the relatively common association of CMs with venous angiomas, which if encountered should not be removed as they represent the venous drainage of the area.
Eichberg et al., reviewed a single institution’s transcortical-transtubular intracranial cavernous malformation resections using either BrainPath endoport system (NICO, Indianapolis, Indiana) or ViewSite Brain Access System (Vycor Medical, Boca Raton, Florida) tubular retractors performed from 2013 to 2018 (n = 20).
Gross total resection was achieved in all patients. When a developmental venous anomaly (DVA) was present, avoidance of DVA resection was achieved in all cases (n = 4). All patients had a supratentorial cavernoma with mean depth below cortical surface of 44.1 mm. Average postoperative clinical follow-up was 20.4 wk. Early neurologic deficit rate was 10% (n = 2); permanent neurologic deficit rate was 0%. One patient (5%) experienced early postoperative seizures (< 1 wk postop). No patients experienced late seizures (> 1 wk follow-up). Engel class 1 seizure control at final clinical follow-up was achieved in 87.5% of patients presenting with preoperative epilepsy.
Tubular retractors provide a low-profile, minimally invasive operative corridor for resection of subcortical cavernomas. There were no permanent neurologic complications in the series of 20 cases, and long-term seizure control was achieved in all patients. Thus, tubular retractors appear to be a safe and efficacious tool for resection of subcortical cavernomas 5).
An online survey composed of 61 items was sent to 26 centers to establish a multicenter international retrospective cohort of adult patients who underwent a surgical resection as the first-line treatment of a supratentorial cavernous angioma located within or close to eloquent brain area.
272 patients from 19 centers (mean 13.6 ± 16.7 per center) from eight countries were included. The pre-operative management varied significantly between centers and countries regarding the pre-operative functional assessment, the pre-operative epileptological assessment, the first given antiepileptic drug, and the time to surgery. The intra-operative environment varied significantly between centers and countries regarding the use of imaging systems, the use of functional mapping with direct electrostimulations, the extent of resection of the hemosiderin rim, the realization of a post-operative functional assessment, and the time to post-operative functional assessment. The present survey found a post-operative improvement, as compared to pre-operative evaluations, of the functional status, the ability to work, and the seizure control.
They observed a variety of practice between centers and countries regarding the management of cavernous angioma located within eloquentregions. Multicentric prospective studies are required to solve relevant questions regarding the management of cavernous angioma-related seizures, the timing of surgery, and the optimal extent of hemosiderin rim resection 6).
Meta-analysis and subgroup analyses were conducted to compare extended lesionectomy with lesionectomy. Pooled analysis demonstrated that seizure outcome was not statistically significantly improved in patients who underwent extended lesionectomy compared with lesionectomy (OR 0.77; 95% CI [0.39-1.51]; P=0.44; I2=15%).
Extended lesionectomy cannot contribute to better seizure control for CCMs with epilepsy. Resection of lesion and surrounding hemosiderin is sufficient for CCMs presenting with epilepsy 7).