Abstract
Objective Gamma Knife stereotactic radiosurgery (GK-SRS) is a preferred treatment option for
tumors of the jugular foramen. We hypothesized that GK-SRS toxicity is higher for
lower cranial nerve schwannomas than for glomus jugulare tumors despite anatomically
similar locations.
Methods We performed a retrospective review of all patients who received GK-SRS for glomus
jugulare tumors and lower cranial nerve schwannomas at our institution between 2006
and 2014. Because of small sample sizes, Fisher's exact tests and logistic regression
techniques were employed using SPSS.
Result We identified 20 glomus jugulare tumors and 6 lower cranial nerve schwannoma patients
with a median follow-up of 17 months. Median marginal dose was 16 Gy (range 13–18
Gy) and 12.5 Gy (range 12–14 Gy), respectively. All except one patient had tumor control
at last follow-up visit. No worsening of pre-existing neurological deficits was observed.
There were seven patients who developed any new neurological deficit after GK-SRS,
four from the glomus group, and three from the schwannoma group (20 and 50% of each
group, respectively). Only two of seven patients had permanent new neurological deficits.
Both of them were in the schwannoma group. Univariate analysis showed that only a
diagnosis of schwannoma had a greater risk of permanent new cranial nerve complication
after GK-SRS compared with diagnosis of glomus jugulare (p = 0.046).
Conclusion Although the marginal dose for glomus jugulare is greater, our study suggests that
the risk of a new permanent neurological deficit after GK-SRS was higher in the schwannoma
group compared with the glomus group.
Keywords
glomus jugulare - lower cranial nerve schwannoma - stereotactic - radiosurgery - Gamma
Knife
