Surgical management of medulla oblongata hemangioblastomas in one institution: an analysis of 62 cases.

Object: Hemangioblastomas of the central nervous system are highly vascularized benign tumors. When the tumors are located in the medulla oblongata, intraoperative bleeding can make the surgical procedure very difficult. Preoperative embolism has been performed in cases of hemangioblastoma in recent decades. However, the complications of the embolization can result in fatal consequences, especially when the lesions are located in the brainstem. In recent years, selectively blocking the suspicious feeding arteries of the tumors during operation in conjunction with intraoperative neurophysiological monitoring has been performed in the Department of Neurosurgery at the West China Hospital. The purpose of this study is to review all cases that underwent this surgical management and to evaluate their outcomes.

Method: Between 2003 and 2014, 62 patients (36 female and 26 male, mean age 35.6 years) underwent microsurgery resection of 67 medulla oblongata hemangioblastomas. The suspicious feeding arteries were identified preoperatively by CTA or DSA. During the operation, the suspicious feeding arteries were blocked selectively by motor evoked potential (MEP) and somatosensory evoked potential monitoring (SEP). Based on the retrospectively review of the clinical records and outpatient long-term follow-up visits, their clinical courses were analyzed. Functional outcomes were evaluated according to the classification of McCormick and the Karnofsky Performance Scale.

Result: The maximum tumor diameter ranged from 0.8 to 5.1 cm (mean, 2.9 cm). Total tumor resection was achieved in 60 patients. Sixty-one tumors were removed en bloc, and the other six were resected in a piecemeal fashion. The mean follow-up period was 47 months. During the follow-up period, 34 patients remained neurologically stable, 27 patients recovered to a better status and 16 patients developed new transient neurological dysfunction. One patient died. Karnofsky performance scale scores were 100 in 14 patients (22.9%), 90 in 18 patients (29.5%), 80 in 24 patients (39.3%) and 40 to 70 in 5 patients (8.2%). Seventeen cases were associated with von Hippel-Lindau (VHL) disease. In all the cases, tumor recurrence was observed during follow-up in only 2 patients.

Conclusion: This study suggests that safe and effective surgical management of medulla oblongata hemangioblastomas can be achieved for most patients, even without preoperative embolization. With the assistance of intraoperative MEP and SEP, mistaken cutting of the vessels that feed the brainstem can be avoided. With improved microsurgical techniques, intraoperative neurophysiological monitoring and a better understanding of the vascular pattern of tumors, total and en bloc microsurgical removal can be performed with low mortality and favorable prognosis of neurological function.