Acoustic Neuroma Recurrence after Translabyrinthine Gross-Total Resection

Objective: To determine the residual/recurrence rate of acoustic neuromas after gross-total resection via translabyrinthine approach.

Introduction: Acoustic neuromas are benign tumors of the internal auditory canal and cerebellopontine angle arising from the Schwann cells of the eight cranial nerve. Treatment may involve microsurgical removal of these tumors. Given their benign nature and the significant morbidity of facial nerve paralysis, complete tumor removal is not always achievable. Often small amounts of tumor are left in situ to preserve the integrity and function of the facial nerve. Resection degree is variable and is subjectively graded intraoperatively as subtotal (STR), near total (NTR), or gross total resection (GTR). Even with intraoperatively graded GTR, it is possible to have residual enhancing tumor on follow-up MRI. In addition, there are reports of recurrence of tumor years after GTR followed by negative surveillance MRI for up to 10 years. The rate of residual tumor after GTR, the rate of recurrence after GTR, and the length of necessary MRI surveillance after GTR are difficult to determine.

Methods: Retrospective assessment of surveillance MRIs performed after translabyrinthine gross total resection of acoustic neuromas was performed. Patients were identified who underwent translabyrinthine resection of acoustic neuroma between 2006 and 2013. Exclusion criteria included <18 years old, prior radiosurgery, or history of neurofibromatosis 2. GTR was confirmed by dictated operative report by a single surgeon. Recurrence rates of tumors based on postoperative MRI imaging were determined. Percentage of patients requiring secondary intervention for recurrent tumors was noted.

Results: One-hundred seventy-six patients met inclusion criteria, and 151 (85.7%) had no evidence of disease (NED) on initial postoperative MRI. Twenty-five patients had radiographic disease on initial follow-up MRI with 8 of the 25 having with disappearance on subsequent MRI. In total, 17 patients (9.7%) had persistent residual tumor with 4 (2.3%) demonstrating minor growth. Zero patients required secondary intervention.

Conclusions: Translabyrinthine gross total resection of acoustic neuromas provide excellent long-term control, and therefore should be strongly considered as initial surgical management. Overall, residual disease rate was <10% with no patients needing secondary intervention.