No abstract

Stapedectomy and stapedotomy are the techniques currently used in the surgical treatment of otosclerosis. During the period 1977-81, a total of 60 consecutive patients were subjected to surgery for otosclerosis according to the method of Schuknecht (Gelfoam and wire prosthesis). Another 55 consecutive otosclerotic patients were operated on during 1987-91with stapedotomy, according to the method advocated by Fisch (Fisch-type piston). Independent of the surgical technique used, the maximal hearing gain was obtained 1 year after surgery. In the frequency range 0.5-3 kHz, the mean value of the averaged pure tone thresholds improved from 52 to 28 dB in the stapedectomy group and from 57 to 26 dB in the stapedotomy group. In the frequency range 4-6 kHz, the subjects' hearing was not significantly improved in the stapedectomy group, whereas the subjects' hearing in the stapedotomy group improved from 61 to 44 dB. Per- and postoperative complications were low in both groups, except for one patient in the stapedectomy group who experienced the serious complication of a deaf ear after surgery.

In this retrospective study of parotid tumours. 57 patients with pleomorphic adenomas were treated with superficial parotidectomy and 33 patients with limited excision. The follow-up period has been 4-14 years. When the operation was superficial parotidectomy, recurrences occurred in 8.7 per cent compared to 6 per cent in cases of limited excision. Side-effects such as permanent weakness of the facial nerve or postoperative gustatory sweating were also more common when superficial parotidectomy was performed. The post-operative results observed suggest that limited excision under magnification is more favourable than superficial parotidectomy in the treatment of pleomorphic adenomas.

Inner ear function was assessed by a frequency-specific (+/-100 Hz) auditory brainstem response (ABR) technique after a single instillation of a suspension of purified E. coli lipopolysaccharide in sterile water into the round window (RW) niche in rats. Instillation of endotoxin caused a transient concentration and tonotopically dependent dysfunction of the inner ear. The largest threshold impairment occurred in the high-frequency region anatomically located close to the RW. At 31.5 kHz the threshold impairment persisted throughout the study. Morphologic damage to the inner ear was not detected at the light microscopic level when using serial sections from decalcified specimens. Our study supports the clinical hypothesis that remnants of non-viable bacteria such as endotoxins, when trapped in the middle ear, can promote middle ear effusion and dysfunction of the inner ear.

Topically applied hydrocortisone was used to develop an animal model for persistent tympanic membrane (TM) perforations. Hydrocortisone suspension was applied on the margins of TM perforations of standardized size in rats once daily for 10 days. The healing patterns of the TMs were mapped weekly and, when the perforations were about to close, daily. After 50 days, all hydrocortisone-treated perforations were open, whereas the controls closed within 9 to 12 days. At 3 months, when one third of the perforations still were open, the TMs were studied by otomicroscopy and light microscopy. All TMs were thickened and covered by keratin and wax. The thickened epidermal layer at the border of the TM perforations that remained open also draped the surface of the perforation facing the middle ear cavity. The thickened connective tissue layer contained abundant fibroblasts with their axes of length oriented at random. Both application of 1.4% hyaluronan and wounding of the perforation border enhanced the healing rate of the hydrocortisone-induced chronic TM perforation.