Unilateral Biportal Endoscopic Removal of Cervical Dumbbell Schwannomas Using a Dual-Tower Bidirectional Approach: A Technical Note With 2 Illustrative Cases

Cervical dumbbell schwannomas are usually managed with open or minimally invasive microsurgical approaches, and endoscopic removal of these tumors has not been previously reported. To our knowledge, this is the first case series describing the feasibility of unilateral biportal endoscopic (UBE) removal of cervical dumbbell schwannomas. Two consecutive patients with cervical dumbbell schwannomas presenting with hemiparesis underwent UBE removal. After laminotomy and medial facetectomy, the extradural tumor was first entered through epineurial and perineurial incisions and disconnected in the subperineurial space. The tumor was then dissected and removed along the established subperineurial plane. The intradural component was subsequently delivered through the dural sleeve from the extradural side. All steps were performed through the same biportal incisions using a dual-tower setup. No instrumented fusion was required. Gross total resection was achieved in one case, and subtotal resection with a residual intradural lesion was achieved in the other. Both patients had full neurological recovery. Asymptomatic occlusion of the nondominant vertebral artery occurred in one case. No cerebrospinal fluid leak, pseudomeningocele, or wound complication was observed. Both patients were followed for more than 1 year, with no tumor recurrence or progression. In the subtotal resection case, the residual intradural lesion was treated with adjuvant stereotactic radiosurgery. This case series demonstrates the technical feasibility of UBE removal of cervical dumbbell schwannomas without instrumented fusion. However, the present experience also highlights important limitations, including vertebral artery occlusion and incomplete intradural removal in a 2-patient series. This approach should therefore be regarded as an emerging technique that requires further refinement of surgical technique and instrumentation rather than as an established alternative.