Functional Outcomes of Microsurgical Resection for Cavernous Malformations of the Brainstem

Long-term functional outcomes of microsurgical resection for cavernous malformations of the brainstem (CMB) have been largely unknown. Favorable outcomes after CMB surgery might be related to the achievement of complete resection and mRS at 1 month after the surgery. Preoperative sensory, cerebellar, trigeminal nerve, and lower cranial nerve symptoms tended to improve after surgery.We evaluated 25 consecutive patients with CMB surgically treated at our center between 2006 and 2021. The subjects included 11 men and 14 women, with ages ranging from 13 to 61 years (mean ± SD = 37 ± 12 years). Modified Rankin Scale (mRS) scores and neurological symptoms of the patients were evaluated before surgery, 1 month after surgery, and at the final follow-up at the outpatient clinic. The mean number of previous hemorrhages was 7 ± 1.0 and the mean lesion size was 21 ± 8 mm. The mRS scores on admission and at the final follow-up were 2.9 points and 1.7 points, respectively. The mRS scores at the final follow-up were significantly improved compared to those on admission. There was no statistical difference between the preoperative mRS and mRS at 1 month after the operation. Multivariable analysis indicated that mRS scores at 1 month after surgery were the most significant predictive factors for favorable outcomes. Complete resection was achieved in 24 of 33 operations. Incomplete resection was significantly related to the frequency of subsequent recurrent hemorrhage and high mRS scores at the final follow-up. Preoperative sensory, cerebellar, trigeminal nerve, and lower cranial nerve symptoms improved significantly after surgery.