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Lin Y, Wang W, Weng H, Lin Y. Predictors of Surgical and Hearing Long-term Results for Inlay Cartilage Tympanoplasty. Arch Otolaryngol Head Neck Surg. 2011;137(3):215–219. doi:10.1001/archoto.2011.10
To determine the prognostic factors that affect surgical and audiologic outcomes in inlay tympanoplasty after long-term follow-up.
Case series study.
Tertiary referral center.
Sixty-two patients who underwent 71 procedures were enrolled in the study. Patient ages ranged from 31 to 87 years (mean [SD] age, 61.2 [12.9] years). Mean (SD) follow-up was 635.7 (284.7) days. The inclusion criteria were (1) inlay cartilage tympanoplasty performed using local anesthesia via a transcanal route, (2) chronic otitis media with stable perforation, and (3) dry ear without middle ear disease.
Main Outcome Measures
The success rate and hearing change at the last follow-up visit.
The overall success rate was 87.3% at the last visit. Using multivariate analysis, sex, age, size of perforation, side of perforation, and the presence of diabetes mellitus and external auditory canal otomycosis did not affect the success. Smoking was the only independent factor for the prognosis of surgical outcome (odds ratio [OR], 8.16; 95% confidence interval [CI], 1.74-36.89; P < .006). On the other hand, age (OR, 6.62; 95% CI, 1.13-38.47; P = .03) and perforation size (OR, 0.11; 95% CI, 0.10-0.79; P = .03) were independent factors for the prognosis of audiologic outcomes.
The frequency of failure was significantly higher for smokers than for nonsmokers. To quit smoking is highly recommended preoperatively for individuals scheduled for chronic otitis media inlay tympanoplasty intervention. Younger patients and those with larger perforations (>50%) were more likely to benefit from this operation.
Inlay tympanoplasty was first described by Eavey in 1998,1 and it has become an accepted method of repairing tympanic membrane perforations.1-8 As originally described, the procedure was performed using a tragal cartilage–perichondrium graft covered by a split-thickness skin graft.1 In 2000, Lubianca-Neto2 used a modified Eavey technique without a split-thickness skin graft over the cartilage graft. The procedures and indications for inlay tympanoplasty have evolved with time. It was first performed on children, thus most of the procedures were conducted under either mask anesthesia or intravenous sedation.1,2 With further experience in adults, however, it is considered an office-based, locally anesthetized procedure.7,8 The indication for inlay tympanoplasty has also evolved from first being used to repair small to medium-sized tympanic perforations1-4,8 to more extensive ear surgery.6
Compared with traditional underlay tympanoplasty, inlay tympanoplasty has several practical advantages. The procedure is usually performed using local anesthesia in an office setting. Only a small incision on the tragus is required. No postauricular incisions are needed because the inlay procedure is performed via a transcanal route. The actual surgical time is shorter than that for underlay tympanoplasty, and no mastoid dressings are needed.7 The success rate and audiometric results of inlay tympanoplasty are similar to those of underlay tympanoplasty. The success rates in previous studies1-9 ranged from 68% to 100%. Hearing level gains and air-bone gap (ABG) closures are as good as those of the underlay procedure.7
Various prognostic factors are reported in the literature10-15 that may affect the surgical success of tympanoplasty. Data are mostly based on the underlay tympanoplasty procedure and involve various degrees of disease severity. Typical candidates for inlay tympanoplasty are recognized as those with simple ear drum perforations without middle ear disease who are of older age or with comorbidity and, thus, unsuitable for general anesthesia. These criteria indicate that typical candidates have less severe ear disease but possibly more severe underlying diseases. It is important to know the surgical outcomes in the inlay tympanic procedure in such patients and to further identify the most suitable candidates for this procedure. On the other hand, the long-term hearing results after surgery are still unknown. Therefore, the aim of this study was to determine the prognostic factors that affect surgical and audiologic outcomes in inlay tympanoplasty.
Between March 1, 2006, and October 31, 2008, a total of 83 patients who received inlay cartilage tympanoplasty were enrolled in the study. Twenty-one patients were excluded owing to follow-up of less than 6 months. Sixty-two patients who underwent 71 procedures (9 patients with bilateral ear surgery) were enrolled in the study. There were 32 male ears and 39 female ears. Patient ages ranged from 31 to 87 years, with a mean (SD) age of 61.2 (12.9) years. Descriptive characteristics of the patients are listed in Table 1. This study was reviewed and approved by the ethics committee of Chang Gung Memorial Hospital at Chiayi, Taiwan, and written informed consent was obtained from all the patients before the surgical intervention.
The inclusion criteria1 were inlay cartilage tympanoplasty performed using local anesthesia via a transcanal route,2 chronic otitis media with stable perforation,3 and dry ear without middle ear disease. Patients without sufficient follow-up of longer than 3 months were excluded from the study. The characteristics of patients and disease were collected. The smoking group was defined as patients with a smoking habit at the time of the operation. Patients who had stopped smoking for 6 months or longer before the operation were defined as nonsmokers. The group with diabetes mellitus was defined as patients with a history of hyperglycemia who were receiving antihyperglycemic drugs at the time of the operation.
The modified inlay cartilage tympanoplasty procedure, as described by Lubianca-Neto,2 was performed in this study. Topical anesthesia was injected subcutaneously with lidocaine hydrochloride, 2%, and epinephrine 1:100 000 into the tragus and the external auditory canal. Tragal cartilage with the perichondrium preserved on one surface had been harvested. We preserve the perichondrium on only 1 side (the outer side) because, in our clinical experience, this makes it easier to approach the perforation site. Denuding around the perforation was performed using a microscope, and then a groove over the margin of the tragal cartilage graft (butterfly fashion) was created. The graft was held with alligator forceps and was inserted onto the perforation site by a transcanal route. The cartilage graft was inserted onto the edge of the freshened perforation margin in a tongue-in-groove manner. No external auditory canal packing was performed.
A successful operation was defined as complete tympanic membrane healing without retraction or lateralization at the last visit. Audiometric results were analyzed in accord with the guidelines of the Committee on Hearing and Equilibrium for the evaluation of results of treatment of conductive hearing loss.16 Audiometric data are expressed as mean (SD), frequency (range), and ABG and were compared using a paired t test. Categorical variables were compared using the χ2 test or the Fisher exact test. Stepwise univariate and multivariate logistic regression analyses were used to identify the most significant combinations of distinguishing variables (patient age, sex, size of perforation, side of perforation, status of diabetes mellitus and smoking, and the presence of postoperative external auditory canal otomycosis). All statistical analyses were performed using statistical software (STATA, version 11.0; StataCorp LP, College Station, Texas). P ≤ .05 indicates a significant statistical difference.
After mean (SD) follow-up of 635.7 (284.7) days (range, 301-1228 days), the success rate of all the patients was 87% at the last visit (Table 1). The success rate was 78% in men and 95% in women (P < .03). Thirteen patients had a smoking habit before and after surgery. The success rate in smokers was 62% and in the nonsmoking group 93% (P < .06). Patient age, size of the perforation, status of diabetes mellitus, and the presence of a postoperative external ear infection did not affect the success rate statistically significantly. Logistic regression analysis was conducted to assess whether the success rate was modified by any baseline characteristics. Smoking habit was the only independent factor for the prognosis of surgical outcome by univariate and multivariate analysis (odds ratio [OR], 8.16; 95% confidence interval [CI], 1.74-36.89; P < .006) (Table 2). The failure rate of smokers was 7-fold higher than that of nonsmokers.
All the patients were asked to undergo audiometry before and after the procedure; however, 5 preoperative and 6 postoperative audiograms were not unavailable because they were acquired in other hospitals. We also excluded 9 patients without total healing of the tympanic membrane and 3 patients with preoperative profound hearing loss. Forty-eight procedures and their preoperative and postoperative audiograms were analyzed. The mean (SD) evaluated time was 635.7 (284.7) days. The mean (SD) preoperative and postoperative hearing thresholds were 52.7 (19.3) dB and 46.6 (21.7) dB, respectively (P = .005). The mean (SD) preoperative and postoperative ABGs were 19.8 (10.3) dB and 12.6 (12.9) dB, respectively (P = .001). In the present patient group, there were no sensorineural hearing changes after surgery. To accurately define the audiologic outcome, we calculated the ABG closure ratio (C), as follows:
A = Preoperative ABGs (dB) – Postoperative ABGs (dB) = Gap Closure (dB) B = Preoperative ABGs (dB) C = A / B (%).
We then stratified the 48 procedures according to the ABG closure ratio: less than 0%, 10 procedures; 0% to 25%, 7 procedures; greater than 25% to 50%, 12 procedures; greater than 50% to 75%, 7 procedures; and greater than 75% to 100%, 12 procedures. Seventy-nine percent of the patients (n = 38) had hearing benefits from this surgery, but 21% (n = 10) had worse results. More than 75% of patients had complete or significant closure rates after surgery (24 patients had ABGs <10 dB in postoperative performance compared with 9 patients in preoperative performance). Patients were divided into better-hearing and worse-hearing groups according to the ABG closure ratio (Table 3). Of patients younger than 60 years, hearing benefits were noticed in 92% (n = 24), whereas only 64% (n = 14) of patients older than 60 years had improvements (P < .05). Hearing benefits were noticed in 96% of patients (n = 22) with a perforation size larger than 50% compared with 64% of patients (n = 16) with a perforation size less than 50% (P < .05). These findings implied that younger patients and those with larger perforations were more likely to benefit from this operation. Other factors, including patient sex, side of perforation, status of diabetes mellitus and smoking, and the presence of external auditory canal otomycosis did not affect the audiologic outcome. Logistic regression analysis was performed to further assess whether the ABG closure ratio was modified by any baseline characteristics. Age (OR, 7.28; 95% CI, 1.30-38.44; P = .02) and size (OR, 0.09; 95% CI, 0.01-0.82; P = .02) were independent factors in univariate analysis. We further analyzed the data using multivariate regression, and age (OR, 6.62; 95% CI, 1.13-38.47; P = .03) and size (OR, 0.11; 95% CI, 0.10-0.79; P = .03) remained independent factors for prognosis of audiologic outcomes (Table 4).
Inlay cartilage tympanoplasty has been proved, in the past decade, to be a feasible, minimally invasive procedure for repairing simple tympanic membrane perforation. Some studies have assessed the benefits and prognostic factors of the success rate.3,5,8 This study focused on the prognostic factors and anatomical and functional outcomes of inlay cartilage tympanoplasty in a retrospective adult series. We focused on simple tympanic membrane perforation, and we performed inlay cartilage tympanoplasty only by excluding the effects of middle ear disease or other surgery. In previous studies, success rates for inlay tympanoplasty have ranged from 68% to 100%. The present study showed an overall success rate of 87%, which is acceptable compared with that of underlay tympanoplasty.7
Sex and smoking showed significant differences in success rates in univariate analysis. In logistic regression analysis, smoking was an independent factor for the success rate. Becvarovski and Kartush10 showed that tobacco use has a significantly negative effect on the long-term results of tympanoplasty. Their study showed delayed failure rates of 60% in smokers and 20% in nonsmokers (P = .05). Smoking habits caused a 3-fold increase in the chance of graft failure.10 Cigarette smoking changes mucus quality and quantity and causes ciliated cell destruction and abnormalities in ciliary function in the middle ear and the Eustachian tube.17 The potential vasoconstrictor effects of nicotine may have a significant effect on graft take. The nicotine effect theoretically compromises the vascular supply to the graft.18 The combination of these factors may increase the chance of failure. In this study, the smoking group had a significantly higher failure rate than the nonsmoking group.
We evaluated the factors that may have altered the change of the postoperative ABGs. Age and size of perforation were independent prognostic factors in the present study, but similar results have not been shown in previous studies. Mauri et al3 showed that bilateral perforations, time of ear cartilage infection, previous tympanoplasty, and tympanosclerosis had no effect on the change in the recovery of ABGs. In this study, older patients (>60 years old) had poorer ABG closure ratios after inlay tympanoplasty. We hypothesize that older patients have a longer infection time, and a longer infection time with older age may lead to poor compliance of the ossicle chain.
The size of the perforation also affects the ABG closure ratio. In this study, patients with larger perforations of the tympanic membrane had better ABG closure ratios after surgery than did those with smaller perforations. Dornhoffer19 compared ABG closure between a cartilage group and a perichondrium group and showed that the size of the perforations and the amount of cartilage did not alter postoperative hearing function. We further propose a possible reason why individuals with larger perforations had better-hearing gain. As with type I tympanoplasty, a larger graft is more likely to be in direct contact with the malleus, causing the “fourth ossicle” effect. Closure of the perforation and increased surface to collect sound might be other causes.
Fifty percent of patients with otomycosis had worse hearing after surgery compared with 17.7% of those without otomycosis; however, there was no statistical significance in this study, which may be due to the small sample size. These findings should be verified with a large series.
In conclusion, smoking is a poor prognostic factor for tympanic healing. The failure rate of inlay tympanoplasty in patients who smoke tobacco was 7-fold higher than that in patients who did not smoke. Also, younger patients and those with larger perforations are more likely to gain hearing benefits from inlay tympanoplasty.
Correspondence: Yen-Chun Lin, MD, Chang Gung Memorial Hospital at Chiayi, No. 6, W Sec, Chiapu Road, Putzu City, Chiayi County 613, Taiwan (firstname.lastname@example.org).
Submitted for Publication: July 1, 2010; final revision received September 12, 2010; accepted September 28, 2010.
Author Contributions: Drs Yi-Chiao Lin and W.-H. Wang contributed equally to the article. All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Yi-Chiao Lin, Wang, and Yen-Chun Lin. Acquisition of data: Yi-Chiao Lin, Weng, and Yen-Chun Lin. Analysis and interpretation of data: Wang, Weng, and Yen-Chun Lin. Drafting of the manuscript: Wang and Yen-Chun Lin. Critical revision of the manuscript for important intellectual content: Yi-Chiao Lin, Wang, Weng, and Yen-Chun Lin. Statistical analysis: Yi-Chiao Lin, Wang, and Weng. Administrative, technical, and material support: Yi-Chiao Lin. Study supervision: Yen-Chun Lin.
Financial Disclosure: None reported.