Issue release date: 18.03.2025

 
Turkish Neurosurgery 2025 , Vol 35 , Num 2
Neuro-Oncology - Tumour Shrinkage and Good Facial Nerve Function After Planned Partial Resection and Gamma Knife Radiosurgery in Koos 4 Vestibular Schwannoma
Mohammed AL-AHMARI1,Max KEIZER2,Bander AL-DHAFERY1,Daniëlle EEKERS3,Koos HOVINGA2,Henricus KUNST4,Yasin TEMEL2
1King Fahad Hospital of Imam Abdulrahman Bin Faisal University, Department of Radiology, Al-Khobar, Zip code 34445, Saudi Arabia
2Maastricht University Medical Centre, Medicine and Life Sciences, Faculty of Health, School for Mental Health and Neuroscience (MHeNS), Department of Neurosurgery, P.O. Box 5800, 6202 AZ Maastricht, the Netherlands
3Maastricht University Medical Centre, GROW ? School for Oncology and Developmental Biology, Department of Radiation Oncology (Maastro),Maastricht, the Netherlands
4Maastricht University Medical Center, Department of Otorhinolaryngology, Maastricht, the Netherlands
5Radboud University Medical Center, Department of Otorhinolaryngology, Nijmegen, the Netherlands DOI : 10.5137/1019-5149.JTN.46381-24.1 AIM: To evaluate clinical and radiological outcome in surgically treated Koos 4 vestibular schwannomas.

MATERIAL and METHODS: Volumetric analysis of the tumour volumes before surgery, after surgery (before radiation), and at follow-up time-points after radiation was performed. Clinical data on facial nerve function and complications were collected. Approximately 6 months after surgery, all patients were treated with a single fraction of stereotactic radiosurgery using the gamma knife radiosurgery with a mean marginal dose of 12.9 Gy to the residual tumour volume.

RESULTS: Mean tumour volume was 11.64 cm3 which was reduced to a mean volume of 4.17 cm3 after partial resection. After a mean follow-up of 100 months, residual tumour showed a decrease in volume in 20 patients, stable disease in one patient and two patients showed progressive tumour volume requiring a second operation in one patient. Facial nerve function was preserved in all patients. One patient suffered from a trigeminal neuralgia after radiation.

CONCLUSION: Planned partial resection followed by radiation for patients with Koos 4 vestibular schwannoma is an effective strategy to preserve facial nerve function and achieve tumour control. Residual tumours after planned partial resection showed a mean decrease in volume of 50% at the last follow-up time point. Keywords : Vestibular schwannoma, Partial resection, Gamma knife, Tumour volume, Facial nerve

Corresponding author : Max KEIZER, max.keizer@mumc.nl