Ashish Vashishth

Effect of mastoid drilling on hearing of the contralateral ear.

OBJECTIVES This study aimed to: understand the effect that high intensity noise associated with drilling (during otological surgery) has on hearing in the contralateral ear; determine the nature of hearing loss, if any, by establishing whether it is temporary or persistent; and examine the association between hearing loss and various drill parameters. METHODS A prospective clinical study was carried out at a tertiary centre. Thirty patients with unilateral cholesteatoma and normal contralateral hearing were included. Patients were evaluated pre-operatively and for five days following surgery using high frequency pure tone audiometry, and low and high frequency transient evoked and distortion product otoacoustic emission testing. RESULTS The findings revealed statistically significant changes in distortion product otoacoustic emissions at high frequencies (p = 0.016), and in transient evoked otoacoustic emissions at both low and high frequencies (p = 0.035 and 0.021, respectively). There was a higher statistical association between otoacoustic emission changes and cutting burrs compared with diamond burrs. CONCLUSION Drilling during mastoid surgery poses a threat to hearing in the contralateral ear due to noise and vibration conducted transcranially.

Cochlear Implantation in Chronic Otitis Media With Cholesteatoma and Open Cavities: Long-term Surgical Outcomes

OBJECTIVES To evaluate the long-term surgical outcomes of cochlear implantation (CI) in chronic otitis media (COM) with cholesteatoma and open cavities using subtotal petrosectomy (STP). To review device explantation (DE) patients and reimplantation considerations. STUDY DESIGN Retrospective review. SETTING Otology and skull base center. PATIENTS AND METHODS Charts of 35 patients (36 ears) with COM with cholesteatoma, including open cavities, who underwent CI were reviewed for surgical outcomes and DE. Patient demographics, pathologies, previous surgeries, staging of implantation, salient intraoperative findings at the time of implantation and follow-up were evaluated. Details of patients with DE were evaluated for cause, operative findings, and reimplantation considerations. RESULTS Mean age of patients was 65.94 years. Nineteen open cavities, 11 primary cholesteatomas, 3 petrous bone cholesteatomas, and 3 atelectatic middle ears represented the pathologies with 31 patients of CI with concurrent STP and 5 patients where implantation was staged. The mean follow-up was 7.16 years ranging from 2 to 13 years. Four patients (11%) had DE due to extrusion and cavity infection with three reimplanted in same or contralateral ear. All explantations occurred within 24 months of primary implantation. No residual or recurrent cholesteatoma was observed in any of the patients during follow-up. CONCLUSION CI is feasible in COM with cholesteatoma and open cavities with the use of STP and single-stage implantation can be performed in the absence of purulence. Despite low risk of residual cholesteatoma post meticulous disease removal, risk of DE remains, particularly in open cavity patients, and is higher than standard implantation. Reimplantation is often possible with careful considerations.

Cartilage Palisades in Type 3 Tympanoplasty: Functional and Hearing Results

Objectives: Evaluate functional and hearing outcomes with use of full thickness broad cartilage palisades for tympanic membrane reconstruction in type 3 tympanoplasty using titanium prosthesis. Methods: The retrospective study done at a tertiary referral institute included 30 patients with posterior mesotympanic retraction pockets or tympanic membrane perforations requiring tympanic membrane and a type 3 ossicular reconstruction. Patients with disease extending beyond aditus requiring canal wall down mastoidectomy were excluded. Disease removal from posterior mesotympanic and epitympanic recesses was confirmed using angled endoscopy and ossicular reconstruction performed using titanium partial or total ossicular replacement prosthesis. The tympanic membrane reconstruction was done, with or without attic reconstruction, using full thickness broad cartilage palisades harvested from the tragus with attached perichondrium laterally. Patients were assessed at 12 and 24 weeks for graft status and any evidence of implant extrusion. Hearing evaluation was done using subjective assessment and pure tone audiometry. Results: Twenty-seven out of 30 patients had intact and completely healed grafts postoperatively at 24 weeks (success rate of 90%) displaying full union and epithelization of palisades, with 3 patients displaying small defects. The mean pure tone air bone gap pre and postoperatively was 32.4 dB and 8.8 dB respectively, with most patients reporting satisfactory postoperative hearing. No evidence of implant extrusion was found in the 24 week period. Conclusions: Tympanic membrane reconstruction using full thickness palisades of tragal cartilage provides good functional and hearing outcomes in type 3 tympanoplasty using titanium prosthesis.

Effect of Mastoid Drilling on Hearing of Contralateral Ear

ceived daily intratympanic saline injections. Outcome Measurements: Auditory brainstem response (ABR) thresholds were determined preand one-day-post-treatment using 4 ms pure-tone bursts between 8 and 32 kHz. Statistical comparisons were completed using student’s two-tailed t-test. RESULTS: Pre-injection mean (SEM) ABR threshold in saline-treated ears was 44.6 dB (1.74) versus 44.1 dB (1.81) in M-ALA-treated ears (p 0.42). Post-injection mean (SEM) ABR thresholds were 45.3 (1.60) for saline-treated ears and 45.6 (1.71) for M-ALA-treated ears (p 0.38). Comparison of preto post-injection ABR thresholds showed no statistical difference within saline-treated (p 0.47) or M-ALA-treated ears (p 0.60). All ears displayed minimal granulation around tympanic membrane injection sites, although M-ALA treated ears showed slightly delayed development of minimal granulation compared to saline ears. Tympanic membranes of both groups showed no difference by 1 week after treatment, with healing perforations and decreasing granulation. CONCLUSION: Intratympanic application of methyl deltaaminolevulinic acid over a 7 day course in a murine model does not produce measurable acute ototoxicity and is well tolerated.