Objective: Brainstem cavernous malformations (BCMs) are low-flow vascular lesions of the central nervous system that pose significant surgical challenges due to their deep location and proximity to eloquent structures. Resection is associated with significant morbidity, and published literature is sparse. This single-institutional, single-surgeon study aimed to delineate factors affecting outcomes in the resection of BCMs and to assess the efficacy of the omnidirectional CO2 laser for lesion resection.
Methods: A retrospective review of all BCMs treated between 1990 and 2022 at Stanford Hospital and Clinics and Lucile Packard Children's Hospital by the senior author was conducted. Data from medical records and direct patient contact data, including presenting symptoms, presence of acute hemorrhage status, time from hemorrhage to surgery, radiological features, surgical approach used, and preoperative and postoperative neurological status, were recorded. The primary outcome assessed included the modified Rankin Scale (mRS) score at baseline and on follow-up. Comparisons were performed between resections with and without the use of the CO2 laser. Further analysis was performed to eliminate "learning curve" bias, and the last 75 patients in both treatment groups were compared.
Results: In total, 277 surgical procedures for BCMs were identified in 254 patients treated from March 1990 to December 2022, and of these 236 (85%) surgical procedures in 215 patients had ≥ 3 months follow-up or mortality within 3 months postsurgery. Of these, 120/236 underwent conventional surgery and 116/236 underwent CO2 laser-assisted resection. Complete resection of the cavernous malformation was achieved in 96.4% of cases. Recurrent BCM was observed in 3/254 (1.2%) of patients, and 70 of 236 cases (30%) had immediate worsening of neurological status, with an average mRS increase of 0.47 points. The CO2 laser-assisted surgery group showed statistically significant long-term mRS score improvement compared to the conventional surgery group (28 [23%] of conventional and 45 [39%] of laser-assisted cases showed improvement; average mRS change +0.125 and -0.241, respectively, p = 0.02). Assessment of the last 75 patients in both groups showed a similar positive relationship between CO2 laser-assisted resection and long-term mRS outcomes (-0.475, 95% CI -0.881 to -0.07, p = 0.02).
Conclusions: BCM remains among the most challenging pathologies for the cerebrovascular neurosurgeon. This series demonstrates that good surgical outcomes are achievable when resection is performed in a high-volume center by an experienced surgeon. Furthermore, this study suggests improved outcomes using the CO2 laser.
Keywords: brainstem cavernous malformation; brainstem surgery; carbon dioxide laser; cavernous malformation resection; single-surgeon series; vascular disorders.