Clinical Presentation
Magnetic resonance imaging confirmed a left-sided mass extending from the internal auditory canal into the cerebellopontine angle, aligning with clinical manifestations of acoustic neuroma [PMID:34864191].
Diagnosis
The diagnosis of a Koos-4 grade vestibular schwannoma was accurately established using MRI, highlighting its utility in assessing tumor extension [PMID:34864191].
Management
The case study demonstrates successful microsurgical gross total resection of an intracanalicular-cisternal vestibular schwannoma using a retrosigmoid approach augmented with endoscopic assistance [PMID:34864191].
In the study by J et al. [PMID:34728398], the use of an endoscope after initial microscopic removal facilitated complete resection of residue tumors in 42.8% of cases, leading to higher rates of serviceable hearing preservation (66.7%) compared to conventional microsurgery (60%).
According to J et al. [PMID:34728398], all patients (100%) in the endoscope group achieved total resection, compared to 75% in the conventional microsurgery group.
In 611 patients undergoing initial surgery from 1973-1994, complete resection was achieved in all but one case intentionally, with a permanent morbidity and mortality rate of 0.3% and temporary morbidity rate of 3.8% [PMID:10575527].
Facial nerve preservation was achieved in 97.6% of cases, with 89.7% maintaining House-Brackmann grade 1 or 2 function at one year post-surgery [PMID:10575527].
Prognosis & Follow-up
The study by J et al. [PMID:34728398] reported that 85.7% of patients in the endoscope group achieved House-Brackmann grade I, indicating good facial nerve function at last follow-up.
Tumour recurrence was observed in only 0.8% of the 1006 surgical cases studied [PMID:10575527].
References
1 Revuelta Barbero JM, Porto E, Medina EJ, Bray DP, Garzon-Muvdi T, Solares CA et al.. Microsurgical Gross Total Resection of an Intracanalicular-Cisternal (Koos-4) Vestibular Schwannoma via a Retrosigmoid Approach with Intraoperative Endoscopic Assistance. World neurosurgery 2022. link 2 Xian-Hao J, Zhen G, Ya-Sheng Y, Wei-Dong Z. Resection of Vestibular Schwannoma Through Middle Cranial Fossa Approach with Endoscopic Assistance. World neurosurgery 2022. link 3 Guerin C, Sampath P, Long DM. Acoustic neuroma: outcome of surgical resection and study on the anatomy of facial and cochlear nerves. Annals of the Academy of Medicine, Singapore 1999. link