Correlation of Site and Size of Tympanic Membrane Perforation and Middle Ear Air Space Volume with Magnitude of Hearing Loss

Abstract

IntroductionThe effects of tympanic membrane perforations on middle ear sound transmission are not well characterized, largely because ears with perforations typically have additional pathological changes. It has been established that the larger the perforation, the greater is the hearing loss (HL). Aim This study aimed to correlate the location and size of tympanic membrane perforation and middle ear air space volume with the magnitude of HL in patients with tubotympanic or inactive mucosal type of chronic otitis media (COM). Materials and Methods A prospective clinical study of patients with tympanic membrane perforations due to COM and without any other ear disease and who attended the Otolaryngology services at our institute between July 2010 and December 2011 was conducted. A total of 300 ears were evaluated by performing otoendoscopy, followed by photo documentation and audiological investigations (pure-tone audiometry and tympanometry). Tympanic membrane perforations were categorized based on their size and location, and the mean air-bone (AB) gap between the various types of perforations was compared and statistically analyzed with significance level of p < 0.05. Results Out of 300 ears, maximum number of ears (n = 124, 41.3%) had large-sized perforations (> 30 mm 2 ) that had a maximum mean AB gap of 26.43 dB, and minimum number of ears (n = 60, 20%) had small-sized perforations (0-9 mm 2 ) that had minimum mean AB gap of 9.12 dB. The remaining were medium-sized perforations that had mean AB gap of 16.13 dB. Depending on the location, maximum were central perforations (n = 198, 66%) and minimum were anterosuperior (AS) perforations (n = 9, 3%). Based on the middle ear volume on tympanometry, maximum ears were of low-volume group (n = 246, 92%) that had larger mean AB gap of 19.96 dB HL when compared with the high-volume group (n = 24, 8%) with 11.80 dB HL. AB gap was maximum at lower frequencies and decreased with increase in frequencies except at 4,000 Hz, that is, 56.9 dB HL at 250 Hz, 42.6 at 500 Hz, 41.5 at 1,000 Hz, 32.4 at 2,000 Hz, and 49.5 at 4,000 Hz. Conclusion HL increases as the area of tympanic membrane perforation increases. There is an inverse relationship between HL and middle ear air space volume. Comparing the small-sized perforations at different sites with the middle ear volume being low, it was found that posterosuperior (PS) perforations had 4 to 7 dB greater HL than AS and anteroinferior (AI). However, the relationship was statistically insignificant. The phase cancellation effect of round window causing greater HL in posteroinferior (PI) perforations does not exist in small-and medium-sized perforations. HL is greater at lower frequencies and less at higher frequencies.Abstract Keywords ► air-bone gap ► chronic otitis media ► various sites and sizes of perforation

Do the size, site and activity of tympanic membrane perforations relate to hearing loss in Aboriginal and Torres Strait Islander children? An observational study.

“…We believe the absence of a significant increase in HL in both active and inactive perforations involving the 50-75% is due to the small number in the 50-75% group, making this a likely Type 1 error. An increase in HL with increased TM perforation size is consistent with the consensus of both theoretical and clinical studies in the literature 4,6,8,[10][11][12]16 . In a study of 78 patients (107 ears) with inactive mucosal COM, perforations were classified as a percentage of total surface area using image processing software 8 .…”

“…It has been generally accepted that hearing loss (HL) is greater with an increase in size of the TM perforation 6 . However, perforation site and the effect on hearing is more controversial with contradictory evidence regarding this [6][7][8][9][10][11][12] . Whilst early work showed worse hearing with posteroinferior based perforations 13,14 , others have found posterosuperior defects to be worse 11,15 and more recent work demonstrated no difference between sites 4,6,7,12 .…”

“…However, perforation site and the effect on hearing is more controversial with contradictory evidence regarding this [6][7][8][9][10][11][12] . Whilst early work showed worse hearing with posteroinferior based perforations 13,14 , others have found posterosuperior defects to be worse 11,15 and more recent work demonstrated no difference between sites 4,6,7,12 . Theories such as loss of the round window baffle effect resulting in phase-cancellation, as well as an increase in ossicular chain abnormalities have been proposed to explain increases in HL with posterior perforations.…”

Adjuvant Migraine Medications in the Treatment of Sudden Sensorineural Hearing Loss

“…Our lack of TM complications or permanent injury with IT injection was consistent with reports in the literature describing its relative safety. 45 However, because multiple IT injections do add theoretical risk to TM injury and may subsequently impact low-frequency PTA, [46][47][48] the investigation of novel treatments that may decrease the number of necessary IT injections, such as the described migraine prophylactic medications, is important. The lack of TM complications following IT injections in our studied cohort can be attributed to: 1) application of a very small amount of phenol (approximately the size of a 25 Ga needle) on the TM to minimize the chance of Laryngoscope 00: 2020…”

The impact of tympanic membrane perforations on middle ear transfer function

“…In a clinical approach, Mehta et al [10] compared posterior and anterior perforations, showing no significant correlation between location and HL, although a trend for a larger air-bone gap of posterior perforations compared to anterior perforations was observed in all frequencies similar to the results of Virk and colleagues [28]. The anatomy and mechanics of the middle ear varies considerably across ears, consequently perforations also effect sound transmission differently.…”