Does concomitant mastoidectomy improve outcomes for patients undergoing repair of tympanic membrane perforations?^†‡

BACKGROUND

Although tympanoplasty with or without mastoidectomy is a common procedure, failures of perforation closure are not a rare occurrence.1 Optimization of the tympanoplasty procedure would lead to improved patient outcomes and increased patient satisfaction. Controversy currently exists amongst otologists regarding the appropriate treatment of tympanic membrane perforations resulting from chronic suppurative otitis media without cholesteatoma. Proponents for mastoidectomy with tympanoplasty for this patient population contend that surgical opening of the mastoid pneumatic system buffers pressure changes in the middle ear according to Boyle's Law and allows for the debridement of infected tissue and devitalized bone that may not be otherwise effectively treated. Anecdotal and empirical data supporting this theory are prevalent within the literature. However, several recent studies investigating tympanoplasty with or without mastoidectomy refute the claim that mastoidectomy improves otologic outcomes following perforation repair.2, 3 We review the current body of literature in an effort to elucidate the best practice.

LITERATURE REVIEW

Several studies have retrospectively reviewed outcomes of tympanoplasty with or without mastoidectomy for the treatment of noncholesteatomatous chronic suppurative otitis media (CSOM) (Table I and Table II. Balyan et al.2 reviewed 323 patients with CSOM. The patients were separated into three groups: group I (n = 53) consisted of patients with draining CSOM treated with tympanoplasty alone, group II (n = 28) consisted of patients with draining CSOM treated with tympanoplasty with mastoidectomy, and group III (n = 242) consisted of patients with nondraining CSOM treated with tympanoplasty alone. The authors found that graft success rates for groups I, II, and III were 90.5%, 85.7%, and 89.2%, respectively. Mean residual gaps for the three groups were 17.2 dB, 20.1 dB, and 19.4 dB, respectively. No statistically significant differences were found for graft success, mean residual gap differences, or between dry and draining ears. Although this analysis was limited in its retrospective design and possible bias in deciding which patients would have mastoidectomy (i.e., did more severe disease bias towards mastoidectomy?), the authors concluded that mastoidectomy is an avoidable procedure in noncholesteatomatous CSOM.2

McGrew et al.1 reviewed 320 patients undergoing tympanoplasty alone and 144 patients undergoing tympanoplasty with mastoidectomy for tympanic membrane perforations related to chronic noncholesteatomatous suppurative otitis media. Perforation repair success was 90.6% and 91.6%, respectively, and postoperative airbone gap was 16.4 ± 12.4 in the tympanoplasty group and 14.4 ± 11.1 in the tympanoplasty with mastoidectomy group. No statistically significant differences were noted for these variables and no power was reported. The authors, noting the likely bias in patient selection associated with the decision to perform mastoidectomy, state that mastoidectomy was more likely performed in younger patients, patients with a higher percentage of ipsilateral pressure equalization tube placement, and in patients with contralateral otologic disease.1 Importantly, the authors of this study provide the most comprehensive analysis of long-term differences between tympanoplasty with and without mastoidectomy. The authors found that patients with tympanoplasty alone were more likely to require subsequent otologic procedures compared with patients who underwent initial concomitant mastoidectomy (15.5% vs. 12.2%), although this did not reach statistical significance (P > .05). The most common subsequent procedures included tympanoplasty, pressure equalization tubes, tympanoplasty with mastoidectomy, and tympanoplasty with canal wall down mastoidectomy. The authors concluded that although the rate of perforation repair was not statistically significant between the two groups, there were clinically significant trends toward improved hearing outcomes and decreased need for subsequent procedures in those receiving a mastoidectomy. The authors believed these trends were strong enough to recommended concurrent mastoidectomy.1

In a study of 251 patients with noncholesteatomatous CSOM, Mishiro et al.4 compared tympanoplasty alone (n = 104) with tympanoplasty with mastoidectomy (n = 147). The authors found that graft success rates were 93.3% and 90.5%, respectively, and found that the postoperatively airbone gap within 20 dB was 90.4% and 81.6%, respectively. No statistically significant differences were noted for these variables or for discharging versus dry ears. The authors concluded that mastoidectomy is not helpful for this population.4

In an evaluation of 47 children undergoing mastoidectomy for noncholesteatomatous CSOM, Rickers et al.5 found an 89% successful perforation repair rate (although two ears underwent reoperation for perforation) and noted that 42% of ears had a normal tympanic membrane at a median postoperative period of 15 years. However, approximately 40% required at least one subsequent operation. Of these, 17% required revision myringoplasty, 13% required a revision mastoidectomy, 10.6% required subsequent PET placement, and 8.5% underwent revision tympanoplasty.5

Finally, in an analysis of 46 patients undergoing tympanoplasty alone and 46 patients undergoing tympanomastoidectomy, Toros et al.3 found perforation closure success rates of 76.1% and 78.3%, respectively, and postoperative airbone gaps of 10.52 ± 8.95 in the tympanoplasty group and 16.77 ± 11.12 in the tympanomastoidectomy group. No statistically significant differences were noted. The authors concluded that mastoidectomy may not be necessary in this patient population.

BEST PRACTICE

Anecdotal and empirical evidence has resulted in the common practice of performing mastoidectomy with tympanoplasty for the treatment of tympanic membrane perforation secondary to chronic noncholesteatomatous suppurative otitis media. Proponents for concomitant mastoidectomy in this patient population cite mastoid aeration and limited increased risks or costs for the patient. As evidenced in the literature, tympanoplasty alone may be sufficient for repair of simple and uncomplicated tympanic membrane perforations.

LEVEL OF EVIDENCE

There is a relative paucity of data regarding mastoidectomy with tympanoplasty for the treatment of tympanic membrane perforation secondary to chronic noncholesteatomatous suppurative otitis media. We present herein four retrospective case-controlled studies with internal controls (level 3 evidence) and one retrospective cohort study (level 4 evidence). As noted in much of the literature, a large prospective, randomized, multi-institutional analysis of mastoidectomy with tympanoplasty would provide much needed data regarding the necessity of and indications for mastoidectomy in this patient population. However, given that most surgeons currently perform mastoidectomy with tympanoplasty especially in patients with increased risk of continued otologic problems (i.e., revision operations, sclerotic mastoid, chronic drainage), such a study may be not be immediately forthcoming.