Tumor Nerve of Origin and Hearing Preservation Outcomes for Patients With Small Vestibular Schwannomas Undergoing Middle Fossa Craniotomy.

OBJECTIVE

To evaluate hearing preservation (HP) outcomes based on tumor nerve origin for patients with small sporadic vestibular schwannomas (VS) undergoing microsurgical resection using the middle cranial fossa (MCF) approach.

STUDY

DESIGN

Retrospective single-institution study.

SETTING

Tertiary academic institution.

PATIENTS: Adults 18 years or older with small sporadic VS (≤15 mm).

INTERVENTION: MCF.

MAIN OUTCOME MEASURE: Hearing preservation is defined as a word recognition score of ≥50%.

RESULTS

Of the 189 consecutive patients who underwent surgery, 164 (89%) had intraoperative identification of the tumor nerve of origin. Of those 164 patients, 88 (54%) had inferior vestibular nerve (IVN) tumors, and 76 (46%) had superior vestibular nerve (SVN) tumors. Hearing was preserved in 83% of patients with SVN tumors compared with 49% of patients with IVN tumors. When stratified by size, the rate of HP was highest (91%) for tumors of SVN origin ≤5 mm in size. In multivariate analysis, patients with SVN tumors ≤5 mm in size had a 7.5-fold increase (95% CI: 1.60-34.9) in HP compared with patients with SVN tumors larger than 10 mm in size. There was no significant difference in facial nerve outcomes between the 2 groups. At initial follow-up, 70 (92%) patients with SVN tumors and 83 (94%) patients with IVN tumors had a HB 1/2, respectively.

CONCLUSIONS

Patients with small SVN tumors have a significantly higher likelihood of HP as well as shorter operative time compared with IVN tumors, suggesting that, in appropriate candidates, early surgical intervention may be beneficial.