Clinical features and surgical outcomes of intramedullary schwannomas

Intramedullary schwannomas are exceedingly rare. Most previous studies are case reports with an associated literature review. The aim of this study was to discuss the clinical features and the outcomes of microsurgery for these rare lesions.

The authors retrospectively reviewed the data of twenty patients with intramedullary schwannomas. All patients had performed preoperative and postoperative magnetic resonance imaging (MRI) and underwent microsurgery. The diagnosis of intramedullary schwannomas was based on radiological and pathological criteria. Modified McCormick classification was applied to assess neurological function.

There were 15 males and five females with a mean age of 44.7 years. Ten tumors were located in the cervical cord, five in the thoracic cord, two in the cervicothoracic cord, two in the thoracolumbar cord and one in the conus medullaris. Patients presented with nonspecific symptoms and the mean duration of symptoms was 37.4 months. Intraoperatively, the tumor was connected to the dorsal rootlet in four cases. Gross total resection (GTR) of the tumor with a well-demarcated dissection plane was achieved in 16 cases, and subtotal resection (STR) was achieved in four cases. No patients received postoperative radiotherapy. During a mean follow-up period of 67.9 months, no recurrence or regrowth of the residual tumors was observed on MRI. Ninety percent of patients experienced an improvement in the McCormick grade and 10 % of patients maintained their preoperative status.

Intramedullary schwannomas are benign but clinically progressive lesions. The accurate diagnosis depends on pathology. For symptomatic patients, early surgery should be performed before neurological deficits deteriorate. When GTR cannot be achieved, STR of the tumor for decompression is advised. Postoperative radiotherapy is not recommended for these benign tumors. A good clinical outcome after GTR or STR can be expected.