Pediatric myringoplasty: Postaural versus transmeatal approach

Abstract

Objectives

Where various surgical options exist for solving the same problem, and the results are similar, Occam's razor may be a suitable way of deciding which technique to use.

The postaural [retroauricular] approach in myringoplasty is favoured generally, for its reported better overview of the middle ear. However, due to increasing interests in both patients’ comfort and a more efficient use of operating time, transmeatal approach is a good alternative. The aim of this study is to investigate the difference in success rates between these two approaches and the factors that contribute to success.

Methods

Retrospective case note study. Cases that achieve tympanic membrane (TM) closure, within 1-year post-operative are considered to be successful.

Patients

A group of 218 ears in 180 patients (median age 10.0, range from 5 to 18 years) who had undergone either postaural or transmeatal myringoplasty with or without ossicular reconstruction. Age, gender, site and size of the perforation, underlying cause of the perforation and status of contralateral ear were recorded. The patients were followed at 6 days, 7 weeks and then every 6 months to determine the incidence of TM closure. Audiograms were taken preoperatively, at 7 weeks and between 7 and 15 months post-operative.

Results

The overall success rate was 78.9%. The difference in the success rates of the two approaches, 79.8% of postaural myringoplasty against 78.4% of transmeatal myringoplasty, is not significant (p = 0.81). Post-operative air bone gap (ABG) is significantly improved when compared to that of preoperative (p ≤ 0.01). Younger age (5–6 years old) is associated with a lower success rate. Though their hearing is significantly improved, the difference is clinically irrelevant.

Conclusion

Postaural and transmeatal approaches in myringoplasty have comparable closure rate. Occam's razor would in this situation indicate the use of the simplest/fastest technique with the lowest morbidity; in this situation the transmeatal approach. Since younger age is associated with lower success rate, it is recommended to postpone surgery until the age of 7 is reached.

Introduction

Many surgical problems have more than one solution, and where the results are similar, it is often difficult to decide which technique to use. In this situation Occam's razor (after William of Occam 13th century English philosopher – “entias non sunt multiplicare sin necesitatum”) employs the simplest and/or fastest/and or least invasive method.

When performing myringoplasty, otologists are faced with at least two choices concerning which approach is to be used during the intervention: postaural, or transmeatal. There is also a third approach feasible, the endaural approach, which is little used in our clinic due to its visible scar. The choice for an approach is, for many surgeons, often determined by their surgical teachers or personal preference [1], [2]. This is mainly due to the lack of scientific evidence of the outcome parameters of the various tympanoplasty techniques [2].

Most otologists have long favoured postaural approach as a standard (one size fits all) approach to the middle ear and mastoid. It is commonly used to expose the mastoid area during the same procedure, enabling a mastoidectomy to be performed if necessary [3]. This approach generally also provides an adequate view of the entire tympanic membrane [4]. Autologous temporalis fascia graft may be harvested without an additional scar. In 1967, Jako [5] described the advantages of postaural exposure over endaural. He stated that postaural exposure preserves more usable tissues and gives a better functional auditory canal as well as providing a better viewing angle of the middle ear.

However, in the same article he also mentioned that endaural incision is less extensive and does not require removal of normal mastoid bone. The approach to the middle ear is shorter than postaural path and the exposure of the middle ear is better. When the aesthetic results of both approaches are compared, the endaural approach achieves a more satisfying result, regardless the graft take and hearing results [3]. Transmeatal approach without external incisions has not been compared to other methods, perhaps due to the continuing bias amongst many otologists that it is suitable only for small and posterior or postero-inferior perforations. In 2008, Seidman [6] did investigate the success rate of anterior transcanal (transmeatal) tympanoplasty. He suggested that it is a minimally invasive procedure that is suitable for anterior perforations, though he did not compare it with perforations located elsewhere. In our hospital we have gradually come to use the transmeatal approach for all perforations, including anterior and subtotal perforations.

In this study, we compared the differences between only the postaural and transmeatal approaches, for the endaural incision leaves a visible scar and is rarely used by us now.

Age remains a controversial factor in assessing a child's suitability for undergoing a myringoplasty procedure. Many otologists have advocated waiting until a given age, due to the belief that an older age is associated with a greater success rate [4], [7], [8], [9]. However, there are also some reports of a comparable success rate in younger children, suggesting that surgery could be done at any age [10], [11], [12], [13]. Especially where larger perforations produce frequent otitis media and significant hearing loss and consequently schooling problems, it may be better to operate earlier. In these patients a hearing aid is often not a good alternative because of the high incidence of otitis media associated with the perforation. Voss et al. [16] has demonstrated that it is the size of the perforation rather than its location that determines the degree of conductive hearing loss.

The size of the perforation is also thought to play a role in determining the success of myringoplasty. Larger perforations are often associated with lower success rate, perhaps due to the extent of the problem and the surgical difficulty it entails [6], [14]. Gaslin et al. [15] however, found that the preoperative perforation size does not significantly correlate with the success rate of the operation, although only a small number (n = 4) of patients with a perforation of ≥3 quadrants was included in that study. This concept of there being no significant difference in success rates in relation to perforation size is shared by Koch et al. [9].

Patients in this pediatric age group frequently remain at risk for developing secretory otitis media and in a small percentage we found that the eardrum developed a pin-hole perforation during healing. Since this does not affect the hearing levels, is not associated with increased incidence of otitis media, and heal spontaneously without requiring further surgery we considered these amongst the successes. This small group was analysed separately to determine if this phenomenon is age related.