Surgical resection of intramedullary spinal cord cavernous malformations: Delayed complications, long-term outcomes, and association with cryptic venous malformations

OBJECTIVE: To examine outcomes and delayed complications after the surgical resection of intramedullary spinal cord (IMSC) cavernous malformations. The association of these lesions with cryptic intraparenchymal venous malformations at surgery also was analyzed. METHODS: The records of 17 patients who underwent resection of their histologically verified IMSC cavernous malformations were analyzed. There were nine female and eight male patients (mean age, 40.1 yr). The locations of the cavernous malformations were as follows: cervical, eight; thoracic, eight; and conus medullaris, one. The mean follow-up period was 48.3 months. Immediate postoperative and long-term neurological outcomes were compared, and delayed complications were assessed. RESULTS: The patients presented with radiculopathy (n = 6), myelopathy (n = 10), and conus medullaris syndrome (n = 1). Intraoperatively, 16 (94.1%) IMSC cavernous malformations were associated with cryptic venous malformations. Immediately after surgery, four (23.5%) patients worsened neurologically whereas one (5.9%) improved. At long-term follow-up, however, 10(58.9%) patients had improved and only 1 (5.9%) remained worse. Four (23.5%) patients experienced delayed complications. Three had undergone incomplete resection and experienced subsequent hemorrhage, necessitating subsequent resection, Another patient developed radiological tethering of the thoracic spinal cord without clinical symptoms. Two of the three patients who had undergone subsequent resection developed symptomatic tethering of the cervical spinal cord. In one of the two patients, the tethering was associated with an iatrogenic cerebellar tonsillar herniation. Both patients required surgical intervention, CONCLUSIONS: The frequent coexistence of IMSC cavernous malformations with cryptic venous malformations in this series indicates a need for operative vigilance to preserve these venous anomalies. Delayed complications were the result of incomplete resection. The resultant hemorrhage required reexploration, which led to tethering of the spinal cord. Most patients who underwent resection, however, had improved neurologically at long-term follow-up.