Clinical Profile and Surgical Outcome of Vestibular Schwannomas: An Institutional Experience

Abstract

AIMS & OBJECTIVES:Vestibular schwannomas manifest with very serious deficits of hearing, facial expression, lower cranial nerve, cerebellar and brain stem functions either preoperatively or as a consequence of surgical intervention. Our objective was to analyse the symptomatology and clinical signs and try to correlate with postoperative outcome and complications in the setting of limited infrastructure, therapeutic and monitoring aids and multisurgeon involvement with varied spectrum of surgical expertise in a single large tertiary teaching institute. METHODS: We retrieved 110 patients with Vestibular schwannomas from the Discharge Summary records of the Department Of Neurosurgery, Nizam's Institute Of Medical Sciences, and Hyderabad from January 2004 to April 2010. The mean age/sex distribution, clinical symptomatology, presenting signs were documented. The operative and clinical findings were evaluated. Data were obtained regarding presenting clinical features, histopathological data after surgical resection, surgical morbidity, mortality and clinical outcome (follow up of 6-12 months). Clinical features and surgical outcome were analysed. RESULTS: The mean tumor size was 4.4 cm. Giant tumours [>4 cm] constituted 74 % of patients. All patients had significant hearing loss which was the most common initial symptom. In 80 % of cases, gross total tumor resection was achieved. In 20 % of cases, deliberate subtotal resections were performed. These were due to adhesions to brain stem in 4 % cases and for facial nerve preservation in 5% cases. Anatomic facial nerve preservation was achieved in 84 % in tumours < 3 cm size. The overall anatomic facial nerve preservation rate was 33.6 %. The rate of functional facial nerve preservation [H-B Grade 1-2] was 67.2 % in cases of small tumors (< 30 mm). The overall functional facial nerve preservation [H-B Grade 1-2] was 28.2 %. Overall mortality was 5.4 % [6 cases] out of which 4.5 % [5 cases] were due to operative site haematoma. CONCLUSION: Hearing loss is the main symptom of vestibular schwannoma. The indication and the timing of tumor resection is dependent on the tumor extension and related necessity of brain stem decompression and on the auditory function. In summary, the chances of good outcomes [Facial nerve preservation and post op morbidity] are best when surgery is performed early [smaller size tumours] and when there is good preoperative facial and lower cranial nerve function. As an optimal goal, completeness of resection with functional Facial nerve preservation is formulated and as an acceptable compromise, near total microsurgical resection with functional Facial nerve preservation is suggested. In the background of a multisurgeon, resource constrained setup an acceptable level of complications and a reasonable outcome can still be achieved. The necessity of intraoperative cranial nerve monitoring, ultrasonic aspirator and the role of surgeon's learning curve cannot be undermined.