Hearing loss in perforations of the tympanic membrane

70 patients with dry central perforations have been studied to assess the hearing loss. The hearing loss is greater at the lower frequencies and increases with the size of the perforation. Malleolar perforations cause more hearing loss than the non-malleolar unless the perforation involves less than 10 per cent of the tympanic membrane surface area. Perforations of the postero-inferior quadrant cause more hearing loss than those in the antero-inferior quadrant.     

Determinants of hearing loss in perforations of the tympanic membrane.

BACKGROUND: Although tympanic membrane perforations are common, there have been few systematic studies of the structural features determining the magnitude of the resulting conductive hearing loss. Our recent experimental and modeling studies predicted that the conductive hearing loss will increase with increasing perforation size, be independent of perforation location (contrary to popular otologic belief), and increase with decreasing size of the middle-ear and mastoid air space (an idea new to otology). OBJECTIVE: To test our predictions regarding determinants of conductive hearing loss in tympanic membrane perforations against clinical data gathered from patients. STUDY DESIGN: Prospective clinical study. SETTING: Tertiary referral center. INCLUSION CRITERIA: Patients with tympanic membrane perforations without other middle-ear disease. MAIN OUTCOME MEASURES: Size and location of perforation; air-bone gap at 250, 500, 1,000, 2,000, and 4,000 Hz; and tympanometric estimate of volume of the middle-ear air spaces. RESULTS: Isolated tympanic membrane perforations in 62 ears from 56 patients met inclusion criteria. Air-bone gaps were largest at the lower frequencies and decreased as frequency increased. Air-bone gaps increased with perforation size at each frequency. Ears with small middle-ear volumes, < or = 4.3 ml (n = 23), had significantly larger air-bone gaps than ears with large middle-ear volumes, > 4.3 ml (n = 39), except at 2,000 Hz. The mean air-bone gaps in ears with small volumes were 10 to 20 dB larger than in ears with large volumes. Perforations in anterior versus posterior quadrants showed no significant differences in air-bone gaps at any frequency, although anterior perforations had, on average, air-bone gaps that were smaller by 1 to 8 dB at lower frequencies. CONCLUSION: The conductive hearing loss resulting from a tympanic membrane perforation is frequency-dependent, with the largest losses occurring at the lowest sound frequencies; increases as size of the perforation increases; varies inversely with volume of the middle-ear and mastoid air space (losses are larger in ears with small volumes); and does not vary appreciably with location of the perforation. Effects of location, if any, are small.     

AlloDerm tympanoplasty of tympanic membrane perforations

PURPOSE: To study the effectiveness of AlloDerm (LifeCell Corporation, Branchburg, NJ) as a graft material in underlay tympanoplasty by comparison to autologous fascia in a chronic tympanic membrane perforation animal model. MATERIALS AND METHODS: Seventeen chinchillas underwent creation of bilateral chronic tympanic membrane perforations over a 6-week period. Twenty-two stable perforations were divided equally between the experimental AlloDerm and control fascia graft groups. The grafts were surgically placed through a postauricular tympanomeatal flap. The tympanic membranes were examined at 4 and 10 weeks and then harvested for histopathological analysis. Tympanoplasty operative times, perforation closure rates, and gross and histological analyses were compared between the AlloDerm and fascia grafts. RESULTS: A statistically significant difference in mean surgical time was recorded between the AlloDerm (47 minutes) and fascia (68 minutes) grafting procedures (t test, P =.001). Perforation closure was achieved in 90% of the AlloDerm and 100% of the fascia treated tympanic membranes. Gross and histopathologic inspections revealed no significant differences. Microscopically, AlloDerm and fascia grafts had similar inflammatory responses, but AlloDerm showed increased fibroblast infiltration and neovascularization. CONCLUSION: The avoidance of donor site morbidity, reduction of surgical time, and excellent gross and histologic outcomes in this animal model reveal that AlloDerm could be a safe, cost-effective alternative to autologous fascia. Further study would be necessary in human clinical trials.     

Tympanic membrane changes in central tympanic membrane perforations

PURPOSE: The objective of this study was to evaluate the histopathological changes in central tympanic membrane perforations caused by chronic otitis media without cholesteatoma. MATERIALS AND METHODS: Twenty-nine temporal bones from 25 patients (13 male patients and 12 female patients) with central tympanic membrane perforations-18 chronic otitis media with perforation and 11 chronic otitis media with perforation caused by ventilation tubes-and 30 aged-matched normal temporal bones were included in this study. A scale was used to evaluate the extension of the migration of stratified squamous epithelium in the inner surface of the tympanic membrane. The thickness of tympanic membranes was measured halfway between the annular ligament and the perforation and compared with that of the normal bones. The presence of tympanosclerosis and papillary projections of squamous epithelium was also noted. RESULTS: The extension of the migration of stratified squamous epithelium in the inner surface of the tympanic membrane was observed in 11 of the 29 perforations (38%). The thickness of tympanic membranes was significantly different between the perforation groups and the control group. Of the 29 tympanic membranes, 13 (44%) had tympanosclerosis and 8 (28%) revealed papillary projections of squamous epithelium. CONCLUSIONS: Our study shows that a central tympanic perforation should not merely be considered as a simple defect. Most of the tympanic membranes showed one or more signs of sequelae or persistent abnormalities such as tympanosclerosis, papillary projections, thickening, and ingrowth without significant differences between the 2 central perforation groups.     

耳内镜下边缘性鼓膜穿孔的治疗

目的探讨耳内镜下治疗边缘性鼓膜穿孔方法和技巧.方法在耳内镜下对22例边缘性鼓膜穿孔患者行鼓室成形术治疗,术中采用耳道"筒形"皮瓣法或双"门形"皮瓣法内植修复鼓膜.结果经3-18个月随访,一次手术治愈率为86.4%.无耳鸣发生或加重,无面瘫、骨导听力下降等并发症发生.结论耳内镜下鼓室成形术是一种安全、简单、微创治疗边缘性鼓膜穿孔的方法,采用双"门形"皮瓣法内植修复边缘性鼓膜穿孔更为简便.     

Acute traumatic tympanic membrane perforations. Cover or observe?

The influence of a paper prosthesis on healing in acute traumatic tympanic membrane perforations was studied in 60 patients randomly selected for a treatment group or a control group. The majority (42 [70%] ) were seen within two days. All patients were treated with oral antibiotics for ten days. The overall healing rate two months after the trauma was 94% (37 of 39 patients). No significant difference between the study group and the control patients was observed. Intermittent secretion was seen in six patients but did not influence the outcome. The perforations occurred in patients with normally sized mastoid air cell systems as seen on roentgenograms. We conclude that acute traumatic tympanic membrane perforations do not need to be treated routinely with paper patching.     

External ear resonance in patients with tympanic membrane perforations.

This study investigated the effects of a tympanic membrane perforation on the external ear resonance. Measurements of external ear resonance using a probe-tube microphone system were performed in 14 patients who had medium to large unilateral tympanic membrane perforations. The contralateral normal ears of these 14 patients served as control. The results showed that there were no significant differences in the peak frequency, peak amplitude and peak sharpness between perforated and normal ears. However, intersubject variability in the resonant frequency was greater in the perforated group. In addition, the resonance curves of these two groups were substantially different. In 10 out of the 14 patients in the perforated group, the resonance curves showed 2-3 prominent peaks separated by valleys of about 10 dB reduced gain. In addition, in 11 out of 14 perforated ears, reduced responses (3.8 dB in average) occurred consistently in the lower frequency region (0.3-2 kHz). Clinically, the abnormal external ear resonance and the larger intersubject variation must be taken into consideration in fitting hearing aids for this group of patients.     

Repair of subtotal tympanic membrane perforations with Seprafilm

OBJECTIVES: We studied the experimental use of Seprafilm, a sheet-like film form of hyaluronic acid, in the repair of subtotal perforations of the tympanic membrane (TM), and the durability of such repairs. METHOD: The research was conducted on 42 Sprague-Dawley rats. Right TMs of all rats were subtotally and thermally perforated in the same fashion. Seprafilm was applied to the perforated TMs of the 21 rats comprising the experiment group. The perforated TMs of the remaining 21 rats, the control group, were left to heal spontaneously. RESULTS: The mean healing times were recorded as 7.8 +/- 0.6 days for the Seprafilm group and 14.9 +/- 1.1 days for the control group (p < 0.001). CONCLUSIONS: These results suggest that Seprafilm may be a possible first choice (before the decision to operate) in subtotal perforations, considering its easy application and patient follow-up.     

Errors in the assessment of tympanic membrane perforations

It is commonly stated that operative closure of large perforations of the tympanic membrane is less successful than closure of small perforations. Few authors mention the exact size of the perforations studied, and fewer still give their method of measuring perforations. We describe a photographic method of assessing the size of perforations relative to the total drumhead, measuring them with a computerized digitizing pad. Thirteen temporal bones were selected at random. Perforations of different sizes, shapes and at different sites were fashioned in the tympanic membranes. These were assessed by clinicians of all grades, who were asked to draw the perforations and give estimates of the perforation size as a percentage of the total drumhead. Visual estimates and drawings were compared with a photographic objective method. Gross errors (some in excess of 100%) were apparent in both estimates and drawings. There was a highly significant statistical difference between the objective method and visual estimates and drawings (P < 0.001). Greater clinical experience was not correlated with better performance in estimating the size of perforations.     

Traumatic tympanic membrane perforations: complications and management

There is great diversity in the methods of treating traumatic perforations of the tympanic membrane. To elucidate the controversy, we present a long-term follow-up study of 37 patients. On the basis of our present study and available relevant data in the literature, we emphasize that early surgical intervention of a traumatic myringeal perforation is not indicated, as most of these perforations (an average of 88%) do heal spontaneously without complications. However, we stress the importance of performing a meticulous auditory and vestibular examination with close follow-up and repeat audiograms in all patients with acute traumatic myringoruptures to provide enough information for diagnosis of a major perilymph leak that would warrant operation. Myringeal perforations or major conductive hearing losses persisting 3 months after injury warrant tympanotomy and appropriate reconstruction.