Surgical approach to C1-C2 nerve sheath tumors.

ABSTRACT

BACKGROUND: C1 and C2 nerve sheath tumors (NST) are unique in presentation, relationship to neighbouring structures and surgical approaches when compared to their counterparts in other regions of the spine. AIM: The strategies involved in the surgery for C1-C2 NST are discussed SETTING AND DESIGN: Retrospective study. METHODS: 21 patients with C1 (n=6) and C2 (n=15) NST were operated based on their position with respect to the cord i.e. anterior (4), anterolateral (10), posterolateral (5), and posterior (2). The tumors had extra- and intradural components in 20 patients; while in one, the tumor was purely intradural. The operative approaches included the extreme lateral transcondylar approach (3); laminectomy with partial facetectomy (5); laminectomy (11); and, suboccipital craniectomy and laminectomy (2). RESULTS: Total excision was performed in 13 patients; while in 7, a partial extraspinal component, and in 1, a small intradural component were left, in situ. Thirteen patients showed improvement by one or more grades in the Harsh myelopathy score; 2 patients with normal power had significant decrease in spasticity; while 5 maintained their grade. One poor-grade patient succumbed to septicemia. CONCLUSIONS: C1-C2 NST may have exuberant growth due to the capacious spinal canal and the absence of a "true" intervertebral foramen at this level. Surgical approaches are determined by its relationship to the cord. A "T incision" on the dura, the partial drilling of the facets, sectioning of the denticulate ligament, rotating the operating table 15 to 30 degrees, and at times sectioning the posterior nerve roots are all useful adjuncts for facilitating access.