DISSERTATION TITLE OF STUDY CORRELATING THE SEVERITY OF CONDUCTIVE HEARING LOSS WITH THE SIZE AND SITE OF PARS TENSA TYMPANIC MEMBRANE PERFORATION USING VIDEO-OTOSCOPY. Principal researche r: Dr. Meera H. Patel-Chudasama. M. Med ENT Surgery. Reg. H58/71914/08. Supervisors: 1. Dr. Mugwe P. Consultant ENT Surgeon, Senior Lecturer, Dept. of Surgery, University of Nairobi. 2. Dr. Patel Asmeeta.I. Consultant ENT Surgeon, ENT Department, Kenyatta National Hospital. A dissertation submitted in part fulfilment of the requirement of the University of Nairobi, for the Award of the Degree of Masters in Medicine in ENT, Head and Neck Surgery 2012. - 1 - DECLARATION This is my original work and has not been presented to the best of my knowledge for a degree in any other university. Signed __________________________________ Date __________________ Dr. Meera H. Patel- Chudasama. This thesis was supervised by: Dr. Mugwe P. Consultant ENT Surgeon. Senior Lecturer, Dept. of Surgery, University of Nairobi. Signed_______________________________Date_____________________ Dr. Patel Asmeeta.I. Consultant ENT Surgeon. ENT Department, Kenyatta National Hospital. Signed_______________________________Date____________________ - 2 - TABLE OF CONTENTS Acronyms and abbreviations …………........................................…….……..................4 Abstract ...........................................................................................................................5 Introduction .....................................................................................................................7 Anatomy...........................................................................................................................12 Physiology .......................................................................................................................14 Pathophysiology ..............................................................................................................16 Literature review ..............................................................................................................17 Justification of study .........................................................................................................25 Aims and objectives ..........................................................................................................27 Materials and methods……………………………………………………………….......28 Quality control .................................................................................................................31 Analysis.............................................................................................................................32 Results................................................................................................................................33 Discussion..........................................................................................................................47 Conclusion.........................................................................................................................52 Recommendations..............................................................................................................52 Study limitations................................................................................................................52 Appendices: Appendix 1- World Health Organization audiometric descriptor Appendix 2-General patient information. Appendix 3-Consent form Appendix 4-Questionaire Appendix 5-Photographs Appendix 6-Budget. References - 3 - ACRONYMS AND ABBREVIATIONS COM- Chronic otitis media. dB - Decibel dBHL - Decibel hearing level. ENT - Ear, Nose and Throat. Hz - Hertz kHz - Kilohertz KNH -Kenyatta National Hospital. MBChB - Bachelor of Medicine and Bachelor of Surgery. TM - Tympanic membrane VO - Video otoscope WHO - World health organization - 4 - CORRELATING THE SEVERITY OF CONDUCTIVE HEARING LOSS WITH THE SIZE AND SITE OF PARS TENSA TYMPANIC MEMBRANE PERFORATION USING VIDEO-OTOSCOPY. ABSTRACT Background: Pars tensa tympanic membrane perforations are associated with a varying degree of conductive hearing loss which is dependent on variables like size and site. In Kenya, use of video-otoscopy is limited thus the description of size and site of the perforations is subjective. Objective: To determine the correlation of degree of conductive hearing loss with the size and site of the pars tensa tympanic membrane perforations using video-otoscopy at the Kenyatta National hospital. Study Design: This was a prospective descriptive study. Materials and methods: The study was carried out in the ENT department of the Kenyatta National Hospital from April 2011 to January 2012. Video otoscope 426/MP was used to take photographs of the perforations. Dino capture 2.0 version 1.3.2.was used to calculate the perforation area. Pure tone audiometry was carried out and results were analysed. Data analysis: Data was tabulated into customized Microsoft Office Access 2007 database proformas. Stata V11.2.was used to carry out the analysis and included the ANOVA, Kruskwal-Wallis, Pearson’s chi square and linear regression methods. Results: A total of 80 ears were included with an equal sex distribution and a median age of 14.5 years. The commonest cause of perforation was chronic otitis media (84%). The overall mean percentage perforation size was 31.35%. Kruskwal-Wallis test: p=0.0001 demonstrated a significant correlation between site of perforation and hearing loss.Anteroinferior - 5 - perforations had an average of 26dBHL and posteroinferior perforations had an average of 44.3dBHL Conclusion: Variables such as the size and site are important aspects in affecting the degree of hearing loss. The larger the perforation the greater the hearing loss.Posterior perforations and those that have a posterior component had a higher hearing threshold. - 6 - INTRODUCTION Tympanic membrane perforations are a condition as old as the evolution of human species and the incidence of tympanic membrane perforation in the general population is unknown as it has not been studied. 1 Hearing loss of any degree is sufficient enough to interfere with social and job related communication and hence can be quite debilitating. It is classified as per the World Health Organization audiometric descriptor. It ranges from normal to profound hearing loss based on the pure tone average. 2 It has been estimated that up to 80% of the tympanic membrane perforations tend to occur in the pars tensa. 3, 4, 5. These tympanic membrane perforations can be classified into either acute perforations or chronic perforations. Acute perforations can be traumatic or inflammatory. Most of these perforations tend to heal spontaneously. Acute otitis media is defined as any ear discharge less than 2 weeks by the World health organization. 6, 7. Acute infections of the middle ear cause tympanic membrane perforation by ischemic necrosis. The middle ear infection gives rise to an increase in pressure in the middle ear space and this results in ischemic necrosis which eventually leads to a tympanic membrane perforation. Chronic perforations are defined as those more than 2 weeks old. They tend to be associated with chronic otorrhoea. Chronic suppuration can occur with or without cholesteatoma or middle ear disease. 6, 7. Chronic ear disease may many times not only result in tympanic membrane perforations but also middle ear disease which can be ruled out clinically by the smell and nature of the ear discharge (Cholesteatoma have a foul smelling, scanty ear discharge). The classification of chronic otitis media is based on the presence of ear discharge, the tympanic membrane and middle ear status. The subtypes include healed chronic otitis media, - 7 - inactive mucosal chronic otitis media, inactive squamous chronic otitis media, active mucosal chronic otitis media and active squamous chronic otitis media. 6,8,9. The old anatomical distinction of either it being a tubotympanic or atticoantral disease has been made redundant with the ability to accurately assess an individual’s ear. The terms safe and unsafe ear are also incorrect and misleading as complications are known to arise from any active ear disease irrespective of the pathology. 8,9 Traumatic perforations of the tympanic membrane can be caused by open-hand blows, injuries by cotton-tipped swabs or foreign bodies, explosions as a result of blast overpressure, welding sparks. 7,10,11. Barometric causes due to atmospheric pressure changes like in flying and scuba diving and iatrogenic causes like vigorous syringing of the ear or surgical intervention during insertion of ventilating tubes can cause tympanic membrane perforations. 7,11. Fracture injuries to the temporal bone can be associated with conductive hearing loss.The pathophysiology includes ossicular chain disruption or tympanic membrane perforation.10,12 Tympanic membrane perforations vary in regards to the subtype of chronic otitis media an individual suffers from. These can include attic perforations, marginal perforations or central perforations.Attic or pars flaccida perforations are almost invariably associated with an invading Cholesteatoma 8. This is now known as the active squamous epithelial chronic otitis media. These perforations usually tend to occur just above the lateral process of the malleus. Many times retraction pockets which are common in the pars flaccida may be confused to be perforations and this is common with the inactive squamous epithelial chronic otitis media.