Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas

Ruangkanchanasetr, Rawee; Lee, John Y.K.; Nagda, S.; Geiger, Geoffrey A.; Kolker, James D.; Bigelow, Douglas C.; Ruckenstein, Michael J.; Nasrallah, MacLean P.; Alonso‐Basanta, Michelle

doi:10.1055/s-0038-1651504

Cited by 4 publications

(2 citation statements)

References 19 publications

(19 reference statements)

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“…1,6,8-41 In addition, 13 studies were included in the systematic review for the SRS cohort series (Table 6). 42-54 In the surgical cohort, females comprised 55% of the primary surgical cohort. Nearly half of the tumors had extracranial extension (46%) although the incidence was highly variable between studies (range 0%-100%).…”

Section: Resultsmentioning

confidence: 99%

Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review

Carlstrom,

Bauman,

Oushy

et al. 2023

Neurosurgery

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BACKGROUND AND OBJECTIVES: Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse. METHODS: A single-institution cohort study and systematic literature review of LCNS were performed. RESULTS: Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients (P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients. CONCLUSION: Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control—particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.

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Section: Resultsmentioning

confidence: 99%

Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review

Carlstrom,

Bauman,

Oushy

et al. 2023

Neurosurgery

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“…Surgery is not the sole option for treating these lesions. Gamma-knife stereotactic radiosurgery has been employed in the treatment of meningiomas [27] and lower cranial nerve tumors [28]. Results on hearing preservation have been published [27] and a mention of hearing improvement has been reported in that series without any audiological data.…”

Section: Discussionmentioning

confidence: 99%

Hearing recovery after surgical resection of non-vestibular schwannoma cerebellopontine angle tumors

Mkrtchyan

Alciato

Kalamaridès

et al. 2021

Eur Arch Otorhinolaryngol

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Purpose: Post-operative outcomes for hearing after resection surgery to remove cerebellopontine angle (CPA) tumors other than vestibular schwannomas (VS) are not well understood. This study presents a series of patients with significant postoperative hearing recovery, trying to define the incidence among all patients operated on for removal of non-VS CPA tumors. Methods: This is a retrospective observational case series of 8 patients among 69 operated on for removal of non-VS CPA tumors between 2012 and 2020. All patients had pre-and post-operative hearing measurement with pure-tone average (PTA) and speech discrimination score (SDS), according to the American Academy of Otolaryngology-Head and Neck Surgery recommendations, auditory brainstem response (ABR) measurements and imaging.Results: Six meningiomas and two lower cranial nerve schwannomas operated on with a retrosigmoid approach were included for analysis. The mean pre-operative PTA and SDS were 58±20.7 dB and 13±17.5%, respectively. All patients had pre-operative class D hearing and asynchronous ABRs. They all showed significant hearing recovery, with an improvement of 36±22.2 dB (p=0.0025) and 85±16.9% (p=0.0001) in PTA and SDS, respectively, with mean follow-up of 21±23.5 months.Seven patients recovered to a class A hearing level and one patient to class B. The ABRs became synchronous for three patients. The incidence of auditory recovery was 13% for patients operated on with a conservative approach (n=60). Conclusion:A significant post-operative improvement in hearing could be a reasonable expectation in non-VS tumors extending into the CPA and a retrosigmoid approach should always be considered regardless of pre-operative hearing status.

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