Role of Tragal Cartilage in Tympanoplasty

Abstract

To determine the outcomes of using tragal cartilage in performing tympanoplasty. It was a prospective study of 57 patients with chronic suppurative otitis media. In all patients, pure tone audiometry was done pre-operatively. Tragal cartilage with attached perichondrium as graft material was used for ossicular chain reconstruction. In fifty out of the 57 participants, the outcome was intact ossicular chain. Of the 7 failures, 5 were recorded in the age group of 51–65 years, where graft uptake failed and hearing was not improved. Two of the failed cases required revision tympanoplasty. Post operative audiograms on follow-up revealed reduced air–bone gaps, with dry tympanic cavity and improved hearing. This study concluded that ossiculoplasty using tragal cartilage as a grafting material was an effective and safe surgical method for reconstruction of the ossicular chain and restoration of sound transmission.

Introduction

Chronic Suppurative Otitis Media (CSOM) is long standing infection of middle ear cleft. It is of two types: tubo-tympanic type and attico-antral type. It is associated with purulent ear discharge and hearing loss. The hearing loss from CSOM is usually of the conductive type and its severity depends on the extent of the disease. The hearing loss is as a result of the chronic infection’s damage to the sound conducting mechanism of the middle ear; which includes the ossicular chain. The hearing loss can be corrected by surgical reconstruction of the middle ear hearing mechanism.

Ossiculoplasty is the reconstruction of the middle ear ossicular chain. The aim of ossiculoplasty is to restore the continuity of the ossicular chain, making it capable of conducting sound waves from tympanic membrane to oval window.

Over the years, various procedures were evolved in the reconstruction of the middle ear sound conducting mechanism. Some of them are used till date. From seventeenth century several attempts have been made for closure of tympanic membrane perforation. Toynbee [1] used gutta percha, a kind of latex rubber mounted on a silver wire.

Wullstein [2] advocated the use of split skin transplantation for repair of tympanic membrane perforation. In Wullstein [2] first used the term tympanoplasty to describe the surgical techniques for reconstruction of the middle ear hearing mechanism.

Okneuff used tri-chloro acetic acid to promote healing of tympanic membrane perforation [3]. Glasscock et al. [4] used vein grafts. He applied the graft on the inner side of the tympanic membrane. Tabb [5] described the placement of fascia on inner side of the tympanic membrane. Foreman [6] used corneal grafts in middle ear reconstructive surgery.

Rizer [3] used frozen fascia lata for tympanic membrane reconstruction.

Kosoy et al. [7] conducted a study on human aortic valves use in middle ear reconstruction. Marquet [8] advocated the use of preserved tympanic membrane homograft for reconstruction. Goodhill et al. [9] used perichondrium as graft tissue for tympanic membrane reconstruction.

Methods

This was a prospective study of patients suffering from chronic suppurative otitis media who presented in department of ENT and Head Neck Surgery at GCS Hospital from June 2017 to June 2018. The inclusion criteria were

1. Dry/quiescent stage of tubo-tympanic type of CSOM;

2. Patients of tubo-tympanic type of CSOM not improving with conservative treatment;

3. Patients with air–bone–gap of at least 20 dBHL.

All participants were evaluated and worked-up by undergoing clinical history, general and otorhinolaryngologic examinations and laboratory investigations of complete blood count, erythrocyte sedimentation rate, Serum creatinine and blood urea. Plain radiographs of mastoid views were done and pure tone audiometry.

Procedure

Ossiculoplasty was carried out on all eligible participants under general or local anaesthesia.

In all patients endaural or post aural approach was used depending upon site and size of perforation. End aural approach was mainly used for posterior perforations.

Tragal cartilage with attached perichondrium as graft material was harvested and used for ossicular chain reconstruction. 1.5 cm incision was made 2 mm medially from the tragal crest line. Skin was undermined and the tragus dissected on both its sides as close as possible to the perichondrium. Cartilage is harvested with knife. Wound is closed with 3–0 interrupted sutures. Dissected cartilage is kept in normal saline until used for reconstruction of the ossicular chain. Cartilage can then be shaped to suit the reconstruction required.

The tympanoplasty was then carried out using standard techniques.

Postoperative Follow-Up

Mastoid bandage was changed the next day. Patient was instructed to keep ears dry.

Course of antibiotics was given for 3 weeks. Gel foam was removed after 2 weeks from external auditory canal.

Post operative micro-otoscopic examination and pure tone audiogram were done to check for graft uptake and hearing thresholds, at 6 weeks and 3 months post-operative periods.

Results

Fifty-seven participants with CSOM, made up of 27 males and 30 females were eligible for the study. The frequencies of their age groups were (Fig. 1):

• 18–35 years = 18;

• 36–50 years = 30 and

• 51–65 years = 9

Fig. 1.

Distribution of age

The mean pre-operative air–bone gap of 44.6 dBHL. 50 (88.4%) participants had intact ossicular chain at 3 months post-operative evaluation. Post operative audiograms on follow up revealed reduced air–bone gaps, with dry cavity and improved hearing. The mean postoperative air–bone gap improved to 20 dBHL (Fig. 2).

Fig. 2.

Mean air bone gap

Five of the 7 failures were recorded in age group of 51–65 years; where graft uptake failed and hearing was not improved. Two of the cases required revision surgery. The causes of the failures were infection in 5 and graft displacement in 2 (Fig. 3).

Fig. 3.

Causes of failure

Discussion

Tympanoplasty is still a developing surgical operation in otolaryngology. The operation removes disease and pathology from the tympanum and reconstructs the tympanic membrane and ossicular chain. The goal is a stable and reliable connection between the tympanic membrane and the mobile stapes footplate, and to achieve the best long term hearing result.

Replacement prostheses can be divided into three types: autograft, homograft (or allograft) and synthetic. Autografts are derived from the same patient and are usually obtained from the temporalis fascia, auricular cartilage (conchal or tragal) or the patient’s own remaining ossicles. Homografts (or allografts) are obtained from other individuals of the same species but with a different genetic makeup. Disadvantages of homografts are the possibility of disease transmission, biocompatibility, and rejection and are more likely to become displaced. Homograft eardrums with complete ossicular chains have been used in the past to reconstruct severely damaged tympanic membranes and middle ears. Synthetic prosthesis are readily available, are presculptured and easy to use. However, they can have difficulties with displacement and extrusions. This was common with the porous polyethylene prostheses which were inserted in the early 1980s, that had a 5 year success rate as low as 22%.

Newer prostheses using biocompatible materials, such as hydroxyapetite titanium, have much higher success rates. Extrusion of synthetic prosthesis can be lowered by the placement of bone or cartilage between the eardrum and the prosthesis.

O’Reilly et al. [10] reported that 27% of patients who underwent ossiculoplasty achieved an air-bone closure within 10 dBHL, and 66.4% within 20 dBHL of the post-operative bone conduction hearing threshold. Average time to the last postoperative audiometric testing was 15.8 months, with a range of 2–62 months. Gajjar and Aiyer [11] reported that 78% of patients who underwent an autologous incus reconstruction had a final air–bone gap less or equal to 30 dBHL. The mean pre-operative air–bone gap was 38.23 dB and the mean postoperative air-bone gap was 18.12 dB. The average gain was 20 dB. The cost of the autograft was null and tolerance was excellent.

In this study, the mean pre-operative air-bone gap of approximately 44.6 dBHL was reduced to 20 dBHL postoperatively, leading to a 24.6 dBHL average gain in hearing. This produced a pleasing level of hearing improvement to the patient.

The survival rate of tragal cartilage graft material is much better than nonbiological materials. Its only few disadvantages are: it lacks stiffness, can sometimes lead to tragal deformity, occasional resorption. The extrusion rate of cartilage is very minimal as compared to the other graft materials. The review of literature revealed the different extrusion rates of different materials, such as autologous, 1.19%, isografts 3.06% the synthetics 5.04%, human dentine 7.14%, gold prosthesis 8.7%. [1–11] Overall, tragal cartilage with perichondrium proved to be good graft materials in reconstructive tympanoplasty.

We studied the use of cartilage as graft material because:

1. Cartilage is more rigid and resists absorption;

2. It has good survival rate as it is nourished largely by diffusion from attached perichondrium for nutrient supply;

3. It is economical and autologous;

4. It can be harvested from the same surgical incision.

Conclusions

In patients with CSOM having hearing loss from ossicular chain damage, this study concluded that ossiculoplasty using the cartilage as a grafting material was an effective and safe surgical method for reconstruction of the ossicular chain and restoration of sound transmission. A cartilage provided not only hearing restoration but also has a very low extrusion rate. The cartilage is also readily available in adequate amount In the vicinity of the surgery, cost effective and can be remolded according to the type of ossicular defect found in the patient.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical Approval

No animals were included in the study and no animal was harmed in the study.

Human Participants Consent

Informed and written consent was taken from all the patients who participated in this study.