A matched cohort comparison of clinical outcomes following microsurgical resection or stereotactic radiosurgery for patients with small- and medium-sized vestibular schwannomas

Abstract

OBJECTIVE A randomized trial that compares clinical outcomes following microsurgery (MS) or stereotactic radiosurgery (SRS) for patients with small- and medium-sized vestibular schwannomas (VSs) is impractical, but would have important implications for clinical decision making. A matched cohort analysis was conducted to evaluate clinical outcomes in patients treated with MS or SRS. METHODS The records of 399 VS patients who were cared for by 2 neurosurgeons and 1 neurotologist between 2001 and 2014 were evaluated. From this data set, 3 retrospective matched cohorts were created to compare hearing preservation (21 matched pairs), facial nerve preservation (83 matched pairs), intervention-free survival, and complication rates (85 matched pairs) between cases managed with SRS and patients managed with MS. Cases were matched for age at surgery (± 10 years) and lesion size (± 0.1 cm). To compare hearing outcomes, cases were additionally matched for preoperative Class A hearing according to the American Academy of Otolaryngology-Head and Neck Surgery guidelines. To compare facial nerve (i.e., cranial nerve [CN] VII) outcomes, cases were additionally matched for preoperative House-Brackmann (HB) score. Investigators who were not involved with patient care reviewed the clinical and imaging records. The reported outcomes were as assessed at the time of the last follow-up, unless otherwise stated. RESULTS The preservation of preoperative Class A hearing status was achieved in 14.3% of MS cases compared with 42.9% of SRS cases (OR 4.5; p < 0.05) after an average follow-up interval of 43.7 months and 30.3 months, respectively. Serviceable hearing was preserved in 42.8% of MS cases compared with 85.7% of SRS cases (OR 8.0; p < 0.01). The rates of postoperative CN VII dysfunction were low for both groups, although significantly higher in the MS group (HB III-IV 11% vs 0% for SRS; OR 21.3; p < 0.01) at a median follow-up interval of 35.7 and 19.0 months for MS and SRS, respectively. There was no difference in the need for subsequent intervention (2 MS patients and 2 SRS patients). CONCLUSIONS At this high-volume center, VS resection or radiosurgery for tumors ≤ 2.8 cm in diameter was associated with low overall morbidity. The need for subsequent intervention was the same in both groups. SRS was associated with improved hearing and facial preservation rates and reduced morbidity, but with a shorter average follow-up period. Facial function was excellent in both groups. Since patients were not randomly selected for surgery, different clinical outcomes may be of different value to individual patients. Both anticipated medical outcomes and patient goals remain the drivers of treatment decisions.

Preserving normal facial nerve function and improving hearing outcome in large vestibular schwannomas with a combined approach: planned subtotal resection followed by gamma knife radiosurgery

“…On the other hand, several large series of radiosurgery for the treatment of small and medium benign skull-base lesions have demonstrated adequate long-term tumor control, along with very low neurological morbidity and improved preservation of functions, especially with regard to the risk for cranial nerve deficit, compared with surgery [20, 39, 41, 59, 66]. In large tumors, radical surgery alone yields a high risk for neurological deficit, and radiosurgery cannot be used safely as a first line of treatment because of the high risk for radiation-induced complications associated with large-volume tumors.…”

The Changing Paradigm for the Surgical Treatment of Large Vestibular Schwannomas

“…17 The outcomes, in terms of facial and cochlear nerve preservation after GKS in patients with small-to medium-sized lesions have considerably increased expectations also for those cases with large tumors. 13,18 Large symptomatic VS are generally considered to be an indication for microsurgical excision because of the need of immediate surgical decompression and symptom alleviation. The sole exceptions are patients with major comorbidities, in which GKS can be used.…”

Therapy of Sporadic and NF2-Related Vestibular Schwannoma

“…A recent cohort study by Golfinos et al compared the outcomes of SRS and surgery in VS patients (tumor diameter ≤ 28 mm). No differences were found in terms of functional outcomes, tumor control and mortalities [108]. Long-term follow-up comparisons between SRS and surgery are still lacking.…”