|Year : 2015 | Volume
| Issue : 2 | Page : 129-133
Hearing benefits in various types of tympanoplasties: A prospective study
Ganesh Kumar Balasubramaniam, Ramanathan Thirunavukkarasu, Ramesh Babu Kalyanasundaram, Hemalatha Palaniappan, Paramaguru Rajesh Shanmugam
Department of ENT and Head and Neck Surgery, Thanjavur Medical College and Hospital, Thanjavur, Tamil Nadu, India
|Date of Web Publication||20-Apr-2015|
Dr. Ganesh Kumar Balasubramaniam
Department of ENT and Head and Neck Surgery, Thanjavur Medical College and Hospital, Thanjavur - 613 004, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Aims: The aim was to study about the hearing benefits achieved by various types of tympanoplasties done for both safe and unsafe type of chronic suppurative otitis media (CSOM). Subjects and Methods: A total of 60 patients with both tubotympanic and atticoantral type of CSOM were taken up and evaluated with otomicroscopy and otoendoscopy, pure tone audiometry and radiological images. Surgeries were planned according to the involvement of the mastoid cavity and extent of the disease, ossicular chain involvement in view of disease clearance and hearing improvement. Statistical Analysis Used: Prospective study design with probability values. Results: Of 60 patients who underwent tympanoplasties 49 patients (81%) showed significant improvement in hearing with successful graft uptake. Conclusions: Mastoidectomy along with tympanoplasty proves beneficial in both disease clearance and hearing improvement. The generally available autologous ossicular grafts like incus or head of the malleus for ossiculoplasty improves the success rate by >80% as shown by us. Aeration of middle ear and infection control postoperatively is essential for functional success after any kind of tympanoplasty as achieved by us.
Keywords: Eustachian tube function, Ossiculoplasty, Pure tone audiogram, Tympanoplasty
|How to cite this article:|
Balasubramaniam GK, Thirunavukkarasu R, Kalyanasundaram RB, Palaniappan H, Shanmugam PR. Hearing benefits in various types of tympanoplasties: A prospective study. Indian J Otol 2015;21:129-33
|How to cite this URL:|
Balasubramaniam GK, Thirunavukkarasu R, Kalyanasundaram RB, Palaniappan H, Shanmugam PR. Hearing benefits in various types of tympanoplasties: A prospective study. Indian J Otol [serial online] 2015 [cited 2019 May 26];21:129-33. Available from: http://www.indianjotol.org/text.asp?2015/21/2/129/155301
| Introduction|| |
Chronic suppurative otitis media (CSOM) in general causes a wide range of middle ear pathologies including irreversible mucosal damages, granulation tissue formation cholesteatoma, ossicular destruction, tympanosclerosis and are classified accordingly in to inactive mucosal, inactive squamous, active mucosal and active squamous type of chronic otitis media (COM)[Table 1]. 
A good clinical evaluation with otoendoscope, an audiometric evaluation and a high resolution computed tomography (CT) of the temporal bone forms a reliable preoperative tool to assess the ossicular status and the disease extent. However, this can only be confirmed per operatively by checking for the ossicular continuity by means of round window light reflex, which is produced even by the slightest movement of the stapes foot plate. The factors influencing the decision for surgery per operatively are ∗ status of middle ear mucosa ∗ amount of bleeding ∗ Eustachian tube function in the involved ear and contralateral ear ∗ advisability of reoperation for a possible cholesteatoma recurrence. A middle ear mucosa that is thickened, infected, traumatized or partially missing is likely to heal with fibrosis that may displace even a perfectly placed the prosthesis. 
The goal of tympanoplasty is to restore sound pressure transformation at the oval window by coupling an intact tympanic membrane (T.M.) with a mobile stapes footplate via an intact or reconstructed ossicular chain and to provide sound protection for the round window membrane by means of a closed, air-conditioned, mucosa-lined middle ear. 
This study attempts at evaluating the hearing benefits achieved by the patients who underwent various types of tympanoplasties based on their disease status.
| Subjects and Methods|| |
This is a prospective study done between October 2013 and June 2014 at our institution with 60 CSOM patients both with tubotympanic and atticoantral type of disease. Inclusion criteria were patients in age group of 10-50 years having unilateral or bilateral ear disease. All the patients had a pure tone conductive type of hearing loss with a good cochlear reserve with varying Eustachian tube function [Table 2]. Initial patient evaluation included a detailed history, otomicroscopic examination, pure tone audiometry (PTA), later high-resolution CT of the temporal bone taken. Any infection of sinuses, tonsils or adenoids were treated.
Certain other preoperative parameters such as age, gender, duration of disease, size of perforation, persistent ear discharge, margin of perforation and its attachment with promontory, polypoidal changes of middle ear mucosa, granulation tissue in middle ear, pure tone average which have influence on ossicular destruction were recorded. PTA was performed in a sound proof room using MAICO MA52 audiometer. Standard head phone was used for air conduction. The PTA was done in every selected patient, comprising frequencies of 250, 500, 1000, 2000, 3000, 4000, 6000 Hz with Carhart and Jerger's technique of 5 up and 10 down method, which is most widely used. For the calculation of average hearing loss (air conduction threshold) three frequencies 500, 1000 and 2000 Hz [Table 1] were selected because they represent speech frequency range, and elevation of threshold in these frequencies will be clinically significant.
The operations are performed under general anesthesia using an operating microscope. The inlay graft technique was used for all perforations. Temporalis fascia graft was used in all patients. After assessing the T.M. and middle ear cavity with otoendoscope, the mastoid cavity was explored, and disease clearance was done in the middle ear and mastoid as necessary. The status of ossicular chain was assessed, and the type of the tympanoplasty procedure was planned according to the status of middle ear and ossicular chain [Chart 1].
All the patients were followed after surgery as usual on 7 th and 14 th day. Audiogram was done on 12 th and 20 th week to assess the improvement of hearing objectively.
| Results|| |
Of the 60 patients who underwent the tympanoplasty in our hospital 49 patients (81%) have a successful graft uptake and hearing improvement, and 11 patients (19%) had graft failure [Table 1].
| Discussion|| |
Chronic otitis media that implies a permanent abnormality of par tensa or flaccida equates the classical term of CSOM, which is not about the "gathering of pus" alone but the distinction between the active COM where there is inflammation of middle ear mucosa and production of pus and which is not the case in inactive COM which has the potential to become active at some time is more important. Resorption of parts or all the ossicles (resorptive osteitis) is a feature of both the active mucosal and active squamous epithelial COM. The ossicles thus affected typically show the hyperemia with proliferation of capillaries and prominent histiocytes. The long process of the incus, stapes crura, body of incus and manubrium are involved in that order of frequency. The reason that the long process of the incus and stapes suprastructure are most frequently affected is likely to be due to their delicate structure and location rather than their tenuous blood supply.  Tympanoplasty is a surgery done to eradicate the disease in the middle ear or mastoid cavity and to reconstruct the hearing mechanism with or without T.M. grafting. It is combined with an intact canal wall or canal wall down mastoidectomy to eradicate the disease from the mastoid cavity and depending upon the type of disease.  Various types of tympanoplasties have evolved and is being done with improvisation mainly in terms of hearing improvement and disease free ear.
The fundamental principles of tympanoplasty  were introduced by Wullstein and Zollner in (1956) and classified tympanoplasty in view of ossicular chain reconstruction (OCR) in to
- Type 1 - All the ossicles are present and mobile. OCR is not needed, and the T.M. graft is placed as an underlay or overlay technique
- Type 2 - Malleus eroded and the T.M. graft is placed on intact incus and stapes
- Type 3 - Also called as myringostapediopexy or columella tympanoplasty. Malleus and incus are absent. Subdivided in to three different types based on the Nadol-Schuknecht modification of the original Wullstein classification: (1) Stapes columella tympanoplasty-placing a T.M. graft directly on the stapes head. (2) Minor columella tympanoplasty-placing a strut or prosthesis between the stapes head and the T.M. graft. (3) Major columella tympanoplasty-placing a strut or prosthesis between the stapes footplate and T.M. graft 
- Type 4 - Only the stapes footplate is present. It is exposed to the external ear. A narrow middle ear (cavum minor) is created by placing the graft between the oval and round windows. Sound waves act directly on the footplate while the round window has been shielded
- Type 5 - Also called fenestration operation in which stapes footplate is fixed, but round window is functioning. Another window is created on dome of horizontal semicircular canal and covered with a graft
- Type 6 - Sonoinversion: All sound waves enter through the round window keeping the oval window covered (reverse direction).
Functional success after tympanoplasty is only partly determined by a surgeon's technical skill. Other factors are some biological and pathological factors.
A number of pathological changes including deposition of fibrous tissue, formation of adhesions and neo-osteogenesis. These tissue responses can compromise middle ear sound transmission in a variety of ways: Fixation of the stapes footplate, ankylosis or displacement of an ossicle strut, immobilization of the round window, immobilization of the T.M., as well as more subtle interference with the mechanics of the T.M. or ossicles.
Another factor leading to failure is total or partial nonaeration of the middle ear and development of negative static middle ear pressure. Total nonaeration of the middle ear is believed to be due to Eustachian tube dysfunction and can lead to severe T.M. atelectasis, middle ear effusion, fibrocystic sclerosis of the middle ear or a combination of these changes.  In our study of 60 cases, patients were decided on their concerned tympanoplasty procedure mainly based on their preoperative finding of their ossicular integrity and the disease extent in mastoid and middle ear cavity. We followed type 1 tympanoplasty for persons with intact ossicular chain and good round window reflex. Some patients had their ossicles eroded by granulation tissue or cholesteatoma. According to reports patients with ossiculoplasty showed significant hearing improvement compared to direct type Wullstein's tympanoplasty.  We preferred ossicular reconstruction by major type 3 tympanoplasty rather than a classical type 3 tympanoplasty in which the graft is placed directly over the head of stapes. In the former procedure, a strut/prosthesis is placed between the stapes footplate and T.M. graft. The prosthesis we commonly used are:
- Autologous incus
- Autologous malleus
- Homologous septal spur cartilage
- Teflon grommet.
A wide variety of autograft, homograft and synthetic materials has been used for reconstructing the ossicular chain. Autologous ossicle grafts (incus or head of the malleus) maintain their morphologic contour, size, shape and physical integrity for long periods of time, over 25 years. They do not incite formation of new bone, nor do they undergo resorption (in the absence of infection). They undergo slow replacement of nonviable bone by new bone formation through the process of "creeping substitution."  The most commonly used autograft material has been the incus body, which is reshaped to fit between the manubrium of the malleus and the stapes capitulum. Advantage with the incus are immediate availability, obvious biocompatibility, low cost and low extrusion rate.  Some disadvantages in it are the lack of availability in chronically diseased ear. Prolonged operative time to reshape the material. Loss of rigidity (especially with cartilage) and possible fixation to walls of the middle ear. Furthermore, osteitis may exist within the ossicles. When the stapes suprastructure is also missing the malleus handle has to be connected to the stapes footplate and autograft materials are rarely suitable, and the success rates of surgery are generally lower.  That more the extent of ossiculoplasty, the poorer the postoperative hearing outcome. 
Other alloplastic materials also in use for reconstruction are:
- Biocompatible - Silastic, titanium, gold, etc
- Bioinert - Aluminium oxide ceramic
- Bioactive - Ceravital, bioglass, hydroxyapatite (less chance for extrusion).
Extrusion and displacement of ossicular prosthesis have been reported in association with Eustachian tube dysfunction, chronic infection, mucosal adhesions and atelectasis. 
The graft we commonly used was temporalis fascia graft. Technique-underlay technique. Advantages with graft ∗ easily available in sufficient quantity, ∗ thickness similar to T.M., ∗adequately firm, ∗low basal metabolic rate, ∗separate incision not required, ∗fascia largely composed of collagen fibers. 
Cartilage grafts are also popular in difficult cases such as large perforations, perforations above tubal orifice, lateralization or atelectasis of T.M. and in revision surgeries. Cartilage is used in the form of several parallel, full thickness strips (palisade technique). Advantage well tolerated in the middle ear, resists retraction and reabsorption, long-term survival as they are largely nourished by diffusion. 
The factors influencing graft uptake, hearing, healing are better aeration of middle ear cavity by well performing Eustachian tube which we ensured by placing an adrenaline soaked cotton ball at the tubal orifice peroperatively and removing it at the end of the procedure and packing the tubal orifice with gel foam for all patients who underwent tympanoplasty.  Postoperative follow-up and infection control with adequate antibiotics and exercise for Eustachian tube patency also have a major influence on graft uptake. Although it is difficult to assess the Eustachian tube function in postoperative visits, the status of the function of Eustachian tube in the opposite ear act as a reasonable guide. 
It is especially important to position the graft tightly in the anterior sulcus where failure of the graft occurs most commonly as a result of the technical error. It is here that the branches of the anterior tympanic and postauricular arteries provide a critical blood supply to the graft.  Site of perforation affects the degree of hearing loss. Big central and central malleolar perforation causes greater hearing loss than other perforation sites.  Most authors also reported less success with the anterior perforation probably because the anterior portion of the T.M. is the least vascular area.  Longer the duration of disease causes more damage to the middle ear mucosa. The degree of involvement of the middle ear mucosa indicates the magnitude of the disease of the mastoid. The hyperplasia of mucosa indicates a bad aeration, which when coupled with tubal dysfunction affects the impedance matching mechanism of the middle ear, accomplished by the (lever action of the ossicles, hydraulic action of T.M. and the curved membrane effect). Furthermore, the phase difference between oval and round window is affected when the cushion of air around the round window is affected. One should create conditions that promote aeration of the round window niche and preserve mobility of the round window membrane (e.g., by preserving all healthy mucosa in protympanum and hypotympanum).  Similarly, the age of the patient also had a greater impact on the outcome of hearing in our study. Older patients had a greater chance of graft failure and failure of hearing improvement, which may be due to delayed wound healing in older age group and lack of cellularity of the mastoid bone.
| Conclusion|| |
In our study we had a remarkable improvement of hearing after our various tympanoplasty procedures, ranging from a minimum of 5 db to a maximum of 24 db improvement [Chart 2] within and across the frequency of 500, 1000, 2000 Hz [Table 3]. We had 81% overall success rate, with >81% in both type 1 and type 3 tympanoplasties and other procedures [Table 4]. Ossiculoplasty with incus graft increased our success rate because of its physical integrity and low extrusion rate. Manipulation of Eustachian tube orifice with adrenaline soaked cotton balls peroperatively also proved fruitful for our success rate. Our finding [Chart 3] also correlates with the postoperative hearing results of the other researchers also. The reason for graft failure and lack of hearing improvement [Chart 4] may be due to inadequate postoperative follow-up of the patients, repeated respiratory tract infection in postoperative period, inadvertent manipulation of the ear by the patient themselves or others.
|Table 3: Comparing mean preoperative and postoperative PTA value with a mean difference and their P value|
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[Table 1], [Table 2], [Table 3], [Table 4]