A Case Series of Surgically Treated Spinal Dumbbell Tumors of Critical Parent Nerve Roots: To Cut or Not to Cut?

Background Dumbbell tumors present challenging cases, with either an incomplete tumor resection or a need to sacrifice nerve roots. Published literature suggests encouraging neurological outcomes after nerve root amputation. Objective To determine the incidence of postoperative neurological deficits after amputating the parent nerve root. Methods A retrospective consecutive analysis of all patients treated for dumbbell nerve sheet tumors with a reported amputation of the functional relevant parent nerve roots C5-Th1 and L3-S1. Results Among 21 evaluated patients, minor postoperative neurological motor function deterioration occurred in 4 patients (19%). Most patients recovered to the preoperative level at the follow-up examination, and only one patient retained a new Medical Research Council (MRC) scale of 4/5 for deltoid weakness. The majority of tumors were resected at the lumbar level (nerve root L3: 28.6%, L5: 19%). Gross total resection was achieved in 90.5% of patients. Neuropathic pain was reported in one third of the patients during the long-term follow-up. Conclusion Amputating critical parent nerve roots during the dumbbell tumor resections seems to result in a low incidence of postoperative motor deficits and may offer an acceptable sacrifice in otherwise only incompletely resectable dumbbell tumors. The cross-innervation of neighboring nerve roots and its, probably, per-se-reduced functionality may be a possible mechanism for maintaining motor function.