Background
Retrospective single-institution (Thomas Jefferson). N=42 unilateral vestibular schwannoma treated with SRS (Gamma Knife n=32; LINAC n=10), 1990–1998. Tumor ≤30 mm, serviceable hearing (GR I–II) in 50%, KPS ≥70.
Interventions and follow up
Treatment: Single-fraction SRS (Gamma Knife n=32 or LINAC n=10) for unilateral VS ≤30 mm
Primary endpoint: Local control, hearing preservation (predictors thereof)
mFollow up: Median 36 mo
Primary endpoint: Local control, hearing preservation (predictors thereof)
mFollow up: Median 36 mo
Results
5-yr local tumor control: 94%
Hearing preservation (serviceable, GR I–II): 75% at last follow-up
Facial nerve function (HB I–II): 100% at last follow-up
Trigeminal neuropathy: 4.8%
Hearing preservation (serviceable, GR I–II): 75% at last follow-up
Facial nerve function (HB I–II): 100% at last follow-up
Trigeminal neuropathy: 4.8%
Adverse events
Facial nerve palsy: 0%
Trigeminal sensory disturbance: 4.8%
Transient tumor expansion (pseudoprogression): 19%
Grade ≥3 / brainstem injury / deaths: None
Trigeminal sensory disturbance: 4.8%
Transient tumor expansion (pseudoprogression): 19%
Grade ≥3 / brainstem injury / deaths: None
Conclusions
SRS achieved 94% 5-yr local control for small-to-medium VS with complete facial nerve preservation and 75% hearing preservation, establishing SRS as a safe alternative to microsurgery in selected patients with superior facial nerve outcomes vs contemporary surgical series.
Key Limitations
Small (N=42), retrospective, single-institution; short median follow-up (36 mo) for a slow-growing tumor; mixed SRS platforms; no surgical comparator arm.
Clinical Context
Early landmark series supporting SRS for small/medium VS; informed dose-reduction strategies (12–13 Gy) that improved hearing and cranial nerve preservation in later practice.