Minimally Destabilizing Corridor for Resection of Dumbbell Nerve Sheath Tumors: A Novel Surgical Technique

Current surgical strategies for dumbbell nerve sheath tumors (DNSTs) with cord compression have primarily involved wide spinal exposures with total laminectomy and unilateral facetectomy, often leading to spinal destabilization and requiring fusion, or staged procedures separately addressing the intraspinal and extraforaminal tumor components. This study highlights technical nuances of a novel approach for DNST resection to minimize spinal destabilization and avoid fusion while facilitating safe, single-stage complete resection.

A retrospective chart review was conducted on patients undergoing DNST resection. Using unilateral subperiosteal dissection, hemilaminotomy and medial facetectomy procedures are performed. The extradural tumor component is resected, followed by internal decompression of the intradural tumor. A small horizontal incision at the origin of the nerve root sleeve releases the underlying dural stricture, facilitating delivery of the remaining intradural tumor and allowing section of the nerve root of origin. Ultrasonography confirms complete tumor resection and return of cord pulsation, and excludes intradural hemorrhagic complications. The dura is reconstructed using a dural substitute bolstered with fat graft and sealant.

Twelve consecutive patients undergoing this approach from 2014 to 2021 were included. Mean patient age was 53.5 years, and 58.3% were male. Nine tumors were cervical and 3 were lumbar. Five patients presented with myelopathy, 4 with radiculopathy, and 4 with axial pain. Two cases had transient intraoperative neuromonitoring signal changes. Eleven tumors were diagnosed as schwannomas and 1 as neurofibroma. All patients had complete resection of the intraspinal component; 2 had far distal extraforaminal residual. No patient has had recurrence, progression of residual, or signs of spinal instability during follow-up (median 28.5 months, range 6-66 months).

This study highlights technical considerations for DNST resection, focusing the approach at the center of the tumor, with minimal bone removal and ligamentous disruption. Intraoperative ultrasound is instrumental in the safety of this approach.