Hearing Status after Stapedotomy in Otosclerotic Patients

Otosclerosis is the most frequent cause of conductive hearing loss in patients with intact tympanic membrane. It can be treated by surgery with various techniques. Because of limited manipulation and comparably similar results, stapedotomy at present is preferred over other surgical techniques by most surgeons. Here we present the operative results of 35 otosclerotic patients who underwent stapedotomy between January 2009 October 2010 in the department of OtolaryngologyHead & Neck Surgery of Bangabandhu Sheikh Mujib Medical University, Dhaka Medical College Hospital and Shahid Suhrawardhy medical college & hospital, Dhaka. The aim of this study was to evaluate the hearing results following stapedotomy in otosclerosis surgery. The average air-bone gap of patients improved significantly to 21.74 dB after operation. Other hearing parameters of patients (including air conduction, bone conduction, speech discrimination score, and tinnitus) also improved. No patient experienced persistent vertigo after the operation and pre operative tinnitus resolved in 12 out of 22 patients. Stapedotomy is a safe and effective modality for improving conductive hearing loss in otosclerotic patients. 1. Assistant Professor of Otolaryngology, Head & Neck Surgery, Sir Salimullah Medical College, Dhaka 2. Assistant Professor of Otolaryngology, Head & Neck Surgery, Sir Salimullah Medical College, Dhaka 3. Professor of Otolaryngology, Head & Neck Surgery, Bangabandhu Sheikh Mujib Medical University, Dhaka 4. Associate Professor of Otolaryngology, Head & Neck Surgery, Bangabandhu Sheikh Mujib Medical University, Dhaka Address of correspondence: Dr. Ahmed Tariq, Assistant Professor, ENT, Sir Salimullah Medical College, Dhaka, E mail atariq26@gmail.com Introduction: Otosclerosis is the most common etiology of conductive hearing loss with an intact tympanic membrane in 15-50 years old patients.1 This is a disorder of bone which is absolutely confined to otic capsule of the temporal bone.2 It causes conductive or mixed hearing loss as well as sensorineural hearing loss. Surgical correction of conductive hearing loss in otosclerosis is one of the most successful procedures in otology. Surgical management requires replacement of all or part of the fixed stapes with or without footplate. Since Shea introduced the procedure of stapedectomy in 1958, much different prosthesis has become available 3. At present the Teflon piston is the most widely used prosthesis for reconstruction of the ossicular chain in cases of otosclerosis. The initial surgical technique of removal of the complete stapes footplate (stapedectomy) has been altered in the so called small fenestra method.4 This trend reflects the thoughts that the limited opening of the vestibule carries a reduced risk of damage to the inner ear.5 Some surgeons have reported better closure of the air bone gap at higher frequencies and better post operative speech discrimination scores (SDS) with small fenestra technique (stapedotomy) compared with stapedectomy.6 There are several factors which influence the surgical outcome after stapedotomy. Literature advocates good outcome with few complications in hands of expert otologists. Stapedotomy has been suggested over stapedectomy to protect the damage to the inner ear and also to improve the long term hearing. Regardless of the technique, it is anticipated that hearing level in otosclerotic patients should improve after surgery in approximately 90% of the cases. Less than 1% of the cases should have severe sensorineural hearing impairment following surgery.7 Historically closure of the air bone gap (ABG) is considered to be the main measure of success for stapes surgery. ABG closure was calculated by comparing post operative pure tone audiometry thresholds for air conduction with pre operative bone conduction thresholds at 3 frequencies (0.5, 1 & 2 KHz). Early reports on large series of stapedotomies demonstrated excellent results, with ABG closure of 10 dB or more in greater than 90% of the patients.8,9 A review of recent studies that included higher frequencies for ABG calculation demonstrated that ABG closure to within 10 dB was achieved in 62 to 94 per cent of patients in recent comparable studies (See Table). In Bangladesh, the incidence of otosclerosis is underdiagnosed as all the cases do not manifest clinically. The patient is relatively unaware of his/ her deafness until it reaches handicap level. Progressive otosclerosis does not associate with earache or discharge, which is a major symptom of ear disease that drives the patient to his physician. Moreover female population is affected twice who is shy to reveal their shortness of hearing and seek attention of her family regarding proper treatment. This study was performed with an intend to see the hearing result of stapedotomy in respect of age, sex and preoperative hearing of the patients.10 Conductive hearing loss arising from otosclerosis is a burden to the individual and also to the family and entire society. Surgical attempt to correct the immobile footplate of stapes is relatively new in our country; few otologic surgeons are doing this operation. Among the learners this operation has gained much popularity considering patient’s hearing improvement, often observed per operatively. There are very few studies regarding outcome of stapes surgery in our country. The aim of the present study was to evaluate the effectiveness of this surgery in management of conductive hearing loss due to otosclerosis in Bangladesh. Results were reviewed regarding hearing improvement and incidence of complications on the background of scientific research methodology. It may guide the future researchers working in this field. Objectives: 1. To find out the improvement of hearing following stapedotomy in otosclerosis patients. 2. To find out hearing gain in relation to preoperative air-bone gap. Methods: Type of study : Cross sectional study Period of study : January 2009 October 2010 86 Hearing Status after Stapedotomy in Otosclerotic Patients Ahmed Tariq et al


Introduction:
Otosclerosis is the most common etiology of conductive hearing loss with an intact tympanic membrane in 15-50 years old patients. 1 This is a disorder of bone which is absolutely confined to otic capsule of the temporal bone. 2 It causes conductive or mixed hearing loss as well as sensorineural hearing loss.
Surgical correction of conductive hearing loss in otosclerosis is one of the most successful procedures in otology. Surgical management requires replacement of all or part of the fixed stapes with or without footplate. Since Shea introduced the procedure of stapedectomy in 1958, much different prosthesis has become available 3 . At present the Teflon piston is the most widely used prosthesis for reconstruction of the ossicular chain in cases of otosclerosis. The initial surgical technique of removal of the complete stapes footplate (stapedectomy) has been altered in the so called small fenestra method. 4 This trend reflects the thoughts that the limited opening of the vestibule carries a reduced risk of damage to the inner ear. 5 Some surgeons have reported better closure of the air bone gap at higher frequencies and better post operative speech discrimination scores (SDS) with small fenestra technique (stapedotomy) compared with stapedectomy. 6 There are several factors which influence the surgical outcome after stapedotomy. Literature advocates good outcome with few complications in hands of expert otologists. Stapedotomy has been suggested over stapedectomy to protect the damage to the inner ear and also to improve the long term hearing.
Regardless of the technique, it is anticipated that hearing level in otosclerotic patients should improve after surgery in approximately 90% of the cases. Less than 1% of the cases should have severe sensorineural hearing impairment following surgery. 7 Historically closure of the air bone gap (ABG) is considered to be the main measure of success for stapes surgery. ABG closure was calculated by comparing post operative pure tone audiometry thresholds for air conduction with pre operative bone conduction thresholds at 3 frequencies (0.5, 1 & 2 KHz). Early reports on large series of stapedotomies demonstrated excellent results, with ABG closure of 10 dB or more in greater than 90% of the patients. 8,9 A review of recent studies that included higher frequencies for ABG calculation demonstrated that ABG closure to within 10 dB was achieved in 62 to 94 per cent of patients in recent comparable studies (See Table).
In Bangladesh, the incidence of otosclerosis is underdiagnosed as all the cases do not manifest clinically. The patient is relatively unaware of his/ her deafness until it reaches handicap level. Progressive otosclerosis does not associate with earache or discharge, which is a major symptom of ear disease that drives the patient to his physician. Moreover female population is affected twice who is shy to reveal their shortness of hearing and seek attention of her family regarding proper treatment. This study was performed with an intend to see the hearing result of stapedotomy in respect of age, sex and preoperative hearing of the patients. 10 Conductive hearing loss arising from otosclerosis is a burden to the individual and also to the family and entire society. Surgical attempt to correct the immobile footplate of stapes is relatively new in our country; few otologic surgeons are doing this operation. Among the learners this operation has gained much popularity considering patient's hearing improvement, often observed per operatively.
There are very few studies regarding outcome of stapes surgery in our country. The aim of the present study was to evaluate the effectiveness of this surgery in management of conductive hearing loss due to otosclerosis in Bangladesh. Results were reviewed regarding hearing improvement and incidence of complications on the background of scientific research methodology. It may guide the future researchers working in this field.

Objectives:
1. To find out the improvement of hearing following stapedotomy in otosclerosis patients.
2. To find out hearing gain in relation to preoperative air-bone gap. 3. Post operative PTA to see hearing results.

Method of sampling
All consecutive cases of stapes surgery were evaluated properly by detailed history taking, clinical examination and investigations. On examination of the ear condition of the pinna, preauricular region, post auricular region and external auditory canal were noted. On otoscopy, the tympanic membrane condition was noted. Tuning fork test, test for facial nerve integrity were performed in every case. Then through examination of the nose and throat was carried out.
Hearing impairment was assessed by pure tone audiometry with or without masking. Xray para nasal sinuses and soft tissue nasopharynx were also done for younger patients to exclude OME.
Majority of the patents were operated under general anaesthesia and rest under local anaesthesia. In all cases, per meatal approach was used. Teflon piston of different diameter was used as prosthetic material. Footplate was preserved in all cases. In patients with bilateral otosclerosis operation was performed in one ear.
Patients were followed up postoperatively for 3 months and after that as per required. During follow-up period condition of the external auditory canal and tympanic membrane was noted. Surgical outcome of the stapedotomy was measured on the basis of subjective improvement of hearing, postoperative hearing gain by PTA, outcome of tinnitus, any relevant complications.

Analysis of data & presentation of results
Hearing gain was assessed by closure of airbone gap 10 . For testing the hypothesis, closure of air bone gaps were studied in two groups d30 dB and >30 dB on the basis of preoperative PTA. All air bone gaps >30 dB were considered as wide AB gap and All air bone gaps d30 dB were considered as narrow AB gap (Table-XVII). Then, closure of air bone gap between two groups measured statistically. All data were compiled, checked and verified thoroughly to reduce the inconsistency. The numerical data obtained were compiled and analyzed using standard statistical tests using scientific calculator and SPSS (ver.15). The results presented in the forms of tables and graphs.
Results:        Almost all studies shows, clinical otosclerosis is more frequent in female with approximate male-female ratio of 1:2. 13 In our series, majority of the patients were male (77.15%) with a male-female ratio 3  23 Quaranta et al, 24 unfortunately, was not obtainable in most of our patients. Closure of post operative air bone gap was 21.74 dB in this series. Preoperative air bone gap was 35.44 dB. Difference between two group was statistically significant by paired t-test (p=0.001, SE= 1.5, x'=14.69). However, post operative air-bone gap <25 dB was considered acceptable by some of the authors. 16 All air bone gaps >30 dB were considered as wide AB gap ( Table-XVIII). Closure of air bone gaps were studied in two group dŠ 30 dB and >30 dB. Closure between two groups was tested by unpaired t test and found not statistically significant (p = 0.0706, t = 1.8687, SE = 3.371); though most of the authors suggest closure of air bone gap to be more in wide air bone gap. 10,18 Sensorineural hearing loss and permanent vertigo are rare following stapes surgery, 1,2 it remains a serious side effect when occurs. In our series none of the patients suffered from total loss of hearing or persistent vertigo. In one case (2.86%) hearing deteriorated and in 3 cases (8.57%) no improvement of hearing observed. Many authors preferred stapedotomy to stapedectomy as there is lesser manipulation of the footplate i.e. the inner ear. 22 Surgery has an unpredictable effect on tinnitus and it may worsen after operation. 25 In our study, 22 (62.85%) patients had tinnitus preoperatively. Of them, 12 (34.28%) patients' tinnitus improved; in 8 (22.85%) patients tinnitus was same as before operation and in 2 (5.71%) patients tinnitus increased. 20,26 As the study was performed over a short period of time with a small number of cases, the results vary considerably from large series. It demonstrates some successful hearing results with low complication rate.