The Effects of Round Window Membrane Injury and the Use of a Model Electrode Application on Hearing in Rats.

OBJECTIVE: To investigate the effects of the mechanical trauma to the round window, a model electrode inserted into the scala tympani on the cochlear reserve, and the efficacy of topical steroids in preventing hearing loss. MATERIALS AND METHODS: 21 male Wistar Albino rats were equally categorized into three groups. In all groups an initial mechanical injury to round window was created. Only subsequent dexamethasone injection was administrated into the cochlea in the subjects of group 2 while a multichannel cochlear implant guide inserted into the cochlea prior to dexamethasone administration for group 3. Distortion product otoacoustic emissions (DPOAEs) were obtained prior to and immediately after the surgical injury, eventually on postoperative seventh day (d 7). Mean signal/noise ratios (S/Ns) obtained at 2000, 3000, and 4000 Hz were calculated. Data sets were compared with non-parametric statistical tests. RESULTS: The early intraoperative mean S/Ns were significantly less than preoperative measurements for group 1 and 2; however, preoperative and postoperative d 7 average S/Ns did not differ. There was statistically significant difference between preoperative, intraoperative and postoperative d 7 average S/Ns for group 3. CONCLUSION: We observed that hearing was restored approximately to the preoperative levels following early postoperative repair. However, an electrode insertion into the cochlea via round window subsequent to mechanical trauma seems to cause a progressive hearing loss. Therefore, a special care must be taken to avoid the injury to the round window membrane in the course of the placement of a cochlear implant electrode and surgery for the chronic otitis media.

Auditory and Histopathological Effects of Topical Mercurochrome Treatment in Rats with Tympanic Membrane Perforation.

OBJECTIVES: Topical treatment is first choice in the treatment of uncomplicated chronic otitis media. It was intended to assess auditory and histopathological safety of ototopical use of mercurochrome solution in rats with induced tympanic membrane perforation. MATERIALS AND METHODS: The study was conducted on 21 female Wistar-Albino rats which were randomly assigned into 3 groups. In all rats, perforation was performed at right tympanic membrane. Distortion product otoacoustic emissions (DPOAEs) measurements were performed at frequencies of 2000, 3000 and 4000 Hz (with L1/L2: 70 /70 dB at 2f1-f2 frequency; f2/f1 ratio: 1:22) before recovery from anesthesia and signal-to-noise ratio (SNR) were recorded. Normal saline, 2% mercurochrome and gentamicin were given to group 1, 2 and 3 twice daily over a week, respectively. Rats were sacrificed after DPOAE measurements on day 14. Right temporal bone specimens were examined under light microscope after processing. RESULTS: Based on DPOAE results, there was no significant difference among groups before treatment. On day 14, significant differences were found in DPOAE measurements at 3000 and 4000 Hz, and in mean SNR values in 2% mercurochrome and gentamicin groups when compared to normal saline group while no significant difference was detected at 2000 Hz among groups. In addition, significant degeneration was detected in Corti organs, spiral ganglions and stria vascularis in groups 2 and 3. CONCLUSION: In this study, it was observed that mercurochrome use in external otitis and otitis media with tympanic membrane perforation could cause ototoxicity and concluded that the solution should be used cautiously.

The effects of round window membrane injury and the use of a model electrode application on hearing in rats.

We conducted an animal experiment to investigate the effects of mechanical trauma to the round window with the placement of a model electrode inserted into the scala tympani on the cochlear reserve, and to determine the efficacy of topical steroids in preventing hearing loss in such a situation. Our subjects included 21 male Wistar albino rats that were assigned into three groups of 7 each. In all three groups, an initial mechanical injury to the round window was created. At that point, group 1 received no further treatment, group 2 received a dexamethasone injection into the cochlea, and group 3 underwent implantation of a multichannel cochlear implant guide followed by dexamethasone administration. After a few minutes, the round window opening was obliterated with muscle, and the incision was sutured with 4-0 Vicryl Rapide polyglactin in all 3 groups. Distortion-product otoacoustic emissions were obtained before and immediately after the surgical injury, and again on postoperative day 7. Mean signal/noise ratios (S/Ns) obtained at 2, 3, and 4 kHz were calculated, and datasets were compared with nonparametric statistical tests. We found that the early postoperative mean S/N values were significantly lower than the preoperative values in groups 1 and 2, but there was no difference between the mean preoperative values and those obtained on postoperative day 7 in those two groups. In group 3, there were statistically significant differences among the mean preoperative, early postoperative, and postoperative day 7 S/N values. We observed that an electrode insertion into the cochlea via the round window subsequent to mechanical trauma seemed to cause a progressive hearing loss. Therefore, we conclude that special care must be taken to avoid injury to the round window membrane during placement of a cochlear implant electrode, as well as during surgery for chronic otitis media.

Revision stapes surgery.

OBJECTIVES: Surgery for otosclerosis has a highly satisfactory hearing outcome, for both the patient and the otologic surgeon. However, subsequent conductive hearing loss, dizziness/vertigo, or sound distortion could necessitate revision surgery. The aim of the present study is to evaluate the surgical findings and hearing outcomes of 84 revision stapes surgeries. STUDY DESIGN: Case series with chart review. SETTING: Tertiary referral center. SUBJECTS AND METHODS: At our institution, 84 revision cases were performed between 1998 and 2009. Conductive hearing loss was the revision indication in 69 cases, severe dizziness/vertigo in 8 patients, sound distortion in 5 cases, and progressive hearing loss with dizziness in 2 patients. Operative findings were noted in every case and evaluated separately. RESULTS: Surgical intervention revealed problems related to prosthesis in 51 cases, fibrotic bands in 26 cases, adhesions in 13 cases, incus necrosis in 15 cases, perilymphatic fistula in 3 cases, intact footplate in 5 cases, incus-malleus fixation in 2 cases, and reobliteration in 2 cases. Mean follow-up period was 19 months (range, 12-53 months). Successful hearing results (air-bone gap <10 dB) were reached in 58% of the cases, and satisfactory hearing results (air-bone gap <20 dB) were reached in 71% of the cases. CONCLUSIONS: The ideal patient for revision stapes surgery is one who benefits from the initial surgery but complained of conductive hearing loss. In the present study, improvement in pure-tone average was 13.2 dB, and the mean air-bone gap was 9.6 dB.

Management of lingual tonsillar hypertrophy using microdebrider.

A female patient presented with globus sensation, chronic cough, and choking attacks. Endoscopic examination showed lingual tonsillar hypertrophy. Partial lingual tonsillectomy was planned. Surgery was performed under local anesthesia in the sitting position, with the use of the microdebrider under the guidance of an endoscope. The operation was accomplished with minimal bleeding. Surgery was very comfortable and easy for both the patient and the surgeon. The microdebrider was found to be effective and useful in the management of lingual tonsillar hypertrophy.

Mucopyocele of the maxillary sinus: a case report.

Mucoceles are defined as chronic, cystic lesions in the paranasal sinuses. When the mucocele content becomes infected, the lesion is defined as mucopyocele. Involvement of the maxillary sinus is rare. A 26-year-old male patient presented with left-sided facial swelling and nasal obstruction that had a history of six months. He had several episodes of sinus infections treated with antibiotics. His visual acuity was not affected. A computed tomography scan showed complete opacification of the left maxillary sinus with expansion through the medial wall of the antrum and hard palate, and thinning and destruction of the adjacent bony structures. The lesion was excised via a sublabial approach. During surgery, the cystic mass had yellowish color with foul-smelling mucopurulent material. In light microscopy, the cystic mass was diagnosed as mucopyocele.