Sunil Goyal1, Shyam Sundar Krishnan2, Mohan Kameswaran3, M C Vasudevan2, Kiran Natarajan4. 1. Department of ENT, Command Hospital (Southern Command), Wanowrie, Pune 411040, Maharashtra, India. Electronic address: drsunilgoyal@yahoo.co.in. 2. Department of Neurosurgery, Dr Achanta Lakshmipathi Neurosurgical Centre, VHS Medical Centre, Adyar, Chennai 600113, Tamil Nadu, India. 3. Department of ENT, MERF-Madras ENT Research Foundation (Pvt) Ltd, 1, First Cross Street, Off Second Main Road, Raja Annamalai Puram, Chennai 600028, Tamil Nadu, India. Electronic address: merfmk30@yahoo.com. 4. Department of ENT, MERF-Madras ENT Research Foundation (Pvt) Ltd, 1, First Cross Street, Off Second Main Road, Raja Annamalai Puram, Chennai 600028, Tamil Nadu, India.
Abstract
OBJECTIVES: The objectives of study was to 1) Describe relevant surgical anatomy in defining and accessing the lateral recess for placement of electrode, 2) Propose a working classification for grades of Flocculus; 3) To determine if different grades of cerebellar flocculus effects placement of ABI electrode and subjective outcomes in implantees. METHODS: Our study was a prospective study, and comprised of cohort of 12 patients who underwent ABI surgery via retrosigmoid approach between 1 Jan 2012 to 31 Dec 2014. All children with congenital profound sensorineural hearing loss with either absent cochlea or cochlear nerve were included in the study. Relevant anatomy was noted. We also noted down the difficulty encountered during the placement of ABI electrode. Auditory perception and speech intelligibility was scored post operatively for 1 year. RESULTS: Cerebellar flocculus was divided into 4 grades depending on the morphology of cerebellar flocculus. It was noted that Grade 3 & 4 flocculus (Group B) had difficult ABI electrode placement in comparison to Grade 1 & 2 flocculus (Group A). The subjective outcomes of Group A was better than Group B. However the p value was not statistically significant. CONCLUSION: Cerebellar flocculus can be graded depending on morphology and size. Flocculus of higher grades can make the placement of ABI electrodes difficult and adversely effects the postoperative subjective outcomes.
OBJECTIVES: The objectives of study was to 1) Describe relevant surgical anatomy in defining and accessing the lateral recess for placement of electrode, 2) Propose a working classification for grades of Flocculus; 3) To determine if different grades of cerebellar flocculus effects placement of ABI electrode and subjective outcomes in implantees. METHODS: Our study was a prospective study, and comprised of cohort of 12 patients who underwent ABI surgery via retrosigmoid approach between 1 Jan 2012 to 31 Dec 2014. All children with congenital profound sensorineural hearing loss with either absent cochlea or cochlear nerve were included in the study. Relevant anatomy was noted. We also noted down the difficulty encountered during the placement of ABI electrode. Auditory perception and speech intelligibility was scored post operatively for 1 year. RESULTS: Cerebellar flocculus was divided into 4 grades depending on the morphology of cerebellar flocculus. It was noted that Grade 3 & 4 flocculus (Group B) had difficult ABI electrode placement in comparison to Grade 1 & 2 flocculus (Group A). The subjective outcomes of Group A was better than Group B. However the p value was not statistically significant. CONCLUSION: Cerebellar flocculus can be graded depending on morphology and size. Flocculus of higher grades can make the placement of ABI electrodes difficult and adversely effects the postoperative subjective outcomes.