Myringoplasty with a single flap.

Abstract

This article describes a myringoplasty technique that involves the use of a single flap of meatal skin and tympanic membrane epithelium. The procedure was performed on 148 patients. A success rate of 90.5% was achieved, with early epithelialization of the grafted tympanic membrane and the avoidance of various problems encountered in the performance of other forms of myringoplasty.

Introduction

Since modern tympanoplastic procedures were described by Wullstein [1] and Zollner [2] in the 1950s, numerous techniques have been developed for the reconstruction of the tympanic membrane. At that time, the grafts of choice were full- and split-thickness skin sections. These techniques soon gave way to canal, vein, perichondrium, and temporalis fascia grafts. There was also some interest in homografts, but the temporalis fascia remains by far the most commonly used graft material. [3]

The controversy over whether to approach the ear through the canal or via the postauricular route is a matter of personal choice. The techniques for placing a graft over or under the drum remnants have been described differently by different authors. Initially, myringoplasty grafts were placed on the outer surface of the tympanic membrane. [4-6] Later on, otologists began to prefer the underlay technique. [3,7-11]

The importance of skin lying superiorly between the tympanosquamous suture in the front and the tympanomastoid suture behind has been well described. [3,4,6,12] This thicker skin was called a vascular strip by Plester. [4] It provides the main blood supply to the upper and central part of the tympanic membrane. It also helps provide vascularization to the graft and promotes epithelialization. Denuding the handle of the malleus and placing the graft under it and on the lateral attic wall under the annulus anteriorly prevents its lateralization. [3]

The speed with which various new techniques have been tried speaks loudly to the desire to overcome the problems routinely encountered in the reconstruction of the tympanic membrane. Among these problems:

* poor exposure to vital areas of the tympanic cavity

* difficulty in removing all squamous epithelium in the area to be covered by the graft and the subsequent formation of epithelial pearls

* the development of disease sequelae, such as tympanosclerosis or the appearance of cicatricial tissue

* the rounding off of the anterior canal recess

* the postoperative migration of the tympanic membrane graft away from the handle of the malleus and retraction of the grafted tympanic membrane

* delayed epithelialization of the graft

* chronic postoperative external otitic dermatitis

* early or late acute middle ear infection and eventual graft failure

* too thick or too thin grafted tympanic membranes

* postoperative sensorineural hearing loss 

The ultimate goal of any grafting procedure is to consistently produce a new tympanic membrane that will function as closely as possible to the original. [3]

The purpose of the study described in this article was to evaluate the results of autograft temporalis fascia myringoplasty with a superiorly based meatal skin and tympanic membrane epithelium flap. The technique eliminates most of the problems encountered in reconstruction of the tympanic membrane defect.

Patients and methods

During a 7-year period, 148 myringoplasties were performed by the described technique. Minimum followup was 6 months. Patients ranged in age from 12 to 60 years; most were aged 21 to 30 years. Active infection of the middle ear was treated by aural toilet and systemic and local antibiotics in an attempt to dry the ear. Patients who had had dry ear for at least 4 weeks were preferred; those with wet ear were excluded. The size of each perforation was noted. In 72% of these cases, there was a large central perforation involving more than 50% of the total drum area; the other 28% had involvement of less than 50%. In all patients, eustachian tube function and cochlear reserve were adequate, and the external auditory canal was sufficiently wide. A preoperative patch test was performed to identify any ossicular chain defects; patients who had such a defect were not included in the study.

Operative technique. The external auditory canal was thoroughly cleansed of any debris or wax 1 day prior to surgery. Patients received systemic sedation and either general or local infiltration anesthesia. Autograft temporal fascia tissue was used, and the graft was obtained by a supra-auricular incision.

After the margins of the perforation were excised, an endomeatal incision was made all around in the deep bony part of the external auditory canal. The incision was made approximately 4 mm lateral to the tympanic annulus, except at its most superior portion opposite Rivinus's notch (figure 1). The mental flap was elevated from lateral to medial until the margins of the eardrum were reached. A cleavage was identified between the meatal flap and the epithelium of the tympanic membrane (figure 2). The epithelium of the tympanic membrane and the meatal flap were gently and gradually raised from the undersurface all around (figure 3). The flap remained attached to the superiormost part of the external auditory canal adjacent to the pars flaccida (figure 4). Any remnants of epithelium that were caused by buttonholing were removed with a cupped forceps. If the anterior remnants of the tympanic membrane were too narrow to support a graft, the mucosa on the medial side was also excised, and the graft was inserted unde rneath. If the handle of the malleus projected into the perforation, a curved needle and cupped forceps were used to excise the periosteum on its lateral and medial surface to ensure a complete excision of squamous epithelium. A raw area was thus created on the remnants of the tympanic membrane and the adjacent portion of the external auditory canal.

A suitably sized graft was cut from the dried temporalis fascia. The middle ear cavity was packed with medicated Gelfoam, beginning in the area of the eustachian tube opening and proceeding to the remainder of the tympanic cavity. The graft was placed on the raw areas of the tympanic membrane and on a portion of the posterior wall of the external auditory canal (figure 5). To avoid blunting, care was taken to bring the graft only to the anterior sulcus and not up to the anterior wall. If the anterior remnants of the tympanic membrane were too narrow to support the graft, the anterior edge of the graft was slipped under the remnants. If the handle of the malleus projected into the perforation, a cut was made in the graft, and the graft was tucked medially to the handle of the malleus to prevent its lateralization (figure 6). The meatal and epithelial flaps that were rolled superiorly were returned to their original positions (figure 7). With a curved needle or cupped forceps, the margins of the epithelium were adjusted to prevent their inversion and to prevent the entrapment of the squamous epithelium. The flap was supported by medicated Gelfoam pieces that were placed in the external auditory canal; except for a cotton ball in the lateral part of the canal, no other packing was used.

Postoperative care. Patients were put on a systemic antibiotic, an antihistamine, and a decongestant. The supra-auricular sutures were removed on postoperative day 7, and the Gelfoam was removed after day 14. Autoinflation was advised for those patients whose grafts were found to be retracting during followup. Postoperative pure-tone audiometry was performed when the graft was considered to be fully taken up and well epithelialized.

Results

Structural results. The criterion for success was the restoration of an intact tympanic membrane. Success was achieved in 134 of 148 cases (90.5%). During the early period of followup, a small residual perforation was noted in the anterior part of the eardrum close to the annulus in eight of the 134 patients. These perforations healed either spontaneously or after the application of trichloroacetic acid to the edges of the perforation.

Among the 14 failures, the graft was only partially taken up in 10 patients, which left a relatively large perforation that did not heal even after repeated cautery; the other four patients experienced a complete graft rejection because of gross sepsis in the middle ear. The size and site of the original perforation and the duration of dryness were not related to outcomes. In the successful cases, the graft was stable and completely epithelialized within 3 weeks of surgery. To date, there has been no evidence of anterior blunting or lateralization of the graft in any of the successful cases.

Functional results. In 116 of the 134 successful cases (86.6%), the air-bone gap improved by at least 10 dB. In the remaining 18 cases (13.4%), hearing did not improve considerably because of poor mobility or retraction of the graft. Postoperative hearing deterioration of either the conductive or perceptive type was not observed in any patient.

Discussion

In a myringoplasty procedure, a number of factors are important for a successful graft takeup. Among them:

* a dry ear, or at least one that is not grossly infected

* adequate operative exposure

* a well-prepared bed for the graft

* proper support or fixation

* an adequate blood supply in the graft

In this series, most patients had dry ear. Operative procedures were performed via the permeatal approach. The external auditory canals were wide and provided good exposure of the operative area. The superior flaps consisted of not only the skin of the vascular strip, but also the entire epithelium of tympanic membrane remnants and the adjacent skin of the external auditory canal. Thus, a sufficiently large raw area was available to serve as the graft bed. The grafts buried under the flap received an early and adequate blood supply. Grafts were supported in place by filling the middle ear cavity with medicated Gelfoam on the inside and on the lateral surface. In patients who had a large perforation, the graft was buried under the annulus anteriorly and medial to the handle of the malleus. In patients who had smaller perforations, the graft was placed lateral to the tympanic membrane remnants without extending it beyond the anterior sulcus. These procedures prevented lateralization of the graft and the roundin g off of the anterior canal recess.

Use of the epithelium of the tympanic membrane remnants helped in its migration across the raw areas over the graft. The early epithelialization and normalization of the grafted tympanic membrane is an additional advantage of this technique. Moreover, this procedure eliminates the chance of epithelium entrapment and the subsequent formation of cholesteatoma pearls.

Residual perforation can occur in the anterior portion of the tympanic membrane as a result of improper support and graft displacement. If the perforation is small and there is no gross sepsis, gradual healing can occur either spontaneously or after local stimulation with trichloroacetic acid. A complete graft failure can be the result of local sepsis associated with an upper respiratory infection.

In this series, hearing improvement was satisfactory in most patients. But in some patients, improvement was not up to the mark because of graft retraction or postoperative scar tissue formation in the middle ear. Undue disturbance of the ossicular chain can lead to postoperative sensorineural hearing loss. Because the ossicular chain was not disturbed in any of the patients in this series, there has been no case of postoperative sensorineural deafness.

From the Department of Otorhinolaryngology--Head ad Neck Surgery, M.L.N. Medical College, Allahabad, India.

Reprint requests: Dr. S.C. Gupta, Associate Professor, Department of Otorhinolaryngology--Head and Neck Surgery, M.L.N. Medical College, Allahabad 211001, India.

References

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(2.) Zollner F. The principles of plastic surgery of sound conduction apparatus. J Laryngol Otol 1955;69:637-52.

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(5.) Sheehy JL. Tympanic membrane grafting: Early and long-term results. Laryngoscope 1964;74:985-98.

(6.) Sheehy JL, Glasscock ME, III. Tympanic membrane grafting with temporalis fascia. Arch Otolaryngol 1967;86:391-402.

(7.) Shea JJ, Jr. Vein graft closure of eardrum perforations. J Laryngol 1960;74:358-62.

(8.) Austin DF, Shea JJ, Jr. A new system of tympanoplasty using vein graft. Laryngoscope 1961;71:596-611.

(9.) Palva T, Palva A, Karja J. Myringoplasty. Ann Otol Rhinol Laryngol 1969;78:1074-80.

(10.) Hough JV. Tympanoplasty with the inferior fascial graft technique and ossicular reconstruction. Laryngoscope 1970;80:1385-413.

(11.) Glasseock ME, III. Tympanic membrane grafting with fascia: Overlay vs. undersurface technique. Laryngoscope 1973;83:754-70.

(12.) House WF, Sheehy JL. Myringoplasty. Use of ear canal skin compared with other techniques. Arch Otolaryng (Chicago) 1961;73:407-l5.