A minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal: a step by step description

Clinicoradiologic Risk Stratification and Outcome Assessment in Symptomatic Intracranial Arachnoid Cyst Managed Over Fifteen Years

BACKGROUND

Arachnoid cysts (ACs) are developmental anomalies formed by splitting the arachnoid membrane's layers. ACs contribute around 2% of all intracranial space-occupying lesions. ACs are more prevalent in children. Because of varied clinical presentation, there has been a constant need for clinicoradiologic risk stratification with a possible role in outcome prediction. The present study describes the management strategies and outcomes in symptomatic intracranial ACs.

METHODS

All biopsy-proven symptomatic patients who underwent surgical management over last 15 years were included in this study (January 2008-December 2022), while those with non-conclusive biopsies were excluded. Patients presenting with acute deterioration were managed in the emergency department with or without cerebrospinal fluid diversion and decompression of the AC. The microsurgical or endoscopic approach was the preferred surgical modality. Postoperative clinicoradiologic improvement was evaluated at 3 months follow-up visit.

RESULTS

A total of 108 patients were analyzed in this retrospective observational study. The median age of the patients was 27.5 years (range, 1 to 76 years). Headache was the most typical clinical presentation. Supratentorial ACs (n = 59, 54.6%) were higher than the infratentorial ACs (n = 49, 45.4%). Forty-seven patients belonged to the pediatric age group (<18 years), and seizure was their presenting complaint. In this observational study, there was no statistical difference in operative duration between microsurgical technique versus endoscopic decompression (P= 0.23).

CONCLUSIONS

ACs are uncommon brain lesions having a broad spectrum of symptoms. The location and clinical presentation of ACs decide the preferred surgical approach. Individuals in high-risk groups must be treated on priority to achieve long-term relief of symptoms.

Arachnoid Cysts of the Internal Auditory Canal: Multiplanar Magnetic Resonance Imaging With Audio-Vestibular Correlates

OBJECTIVES/HYPOTHESIS

To investigate prevalence, radiological characteristics, and functional correlates of arachnoid cysts (AC) of the internal auditory canal (IAC) region, including associations of nerve compression with auditory/vestibular symptoms and asymmetrical audiogram or vestibular testing.

STUDY DESIGN

Retrospective study.

METHODS

T2-weighted magnetic resonance imaging (MRI) studies of IACs were retrospectively analyzed from 1247 patients with asymmetric auditory or vestibular symptoms. Patients with radiological findings of AC of the IAC were identified. Multiplanar analysis was used to analyze cyst position in the IAC and assess nerve displacement or compression. Size, position, and presence of nerve compression were correlated with symptoms.

RESULTS

Twenty-four patients had a cyst in the middle or fundus in the IAC. Diameter (P = .04) and position (P = .002) of AC were associated with symptoms. Sagittal analyses identified displacement versus compression (P = .003) more reliably than axial imaging. Symptom laterality was associated with the site of radiological abnormality. Vestibular nerve compression was associated with vertigo (P = .0001), and cochlear nerve compression was associated with auditory symptoms (P < .0001).

CONCLUSIONS

In a retrospective series of patients undergoing MRI of IACs for asymmetric auditory or vestibular impairment, clinical symptom profile correlated with blinded assessment of IAC lesions.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:2323-2331, 2021.