The Reaction of Unerodable Porous Polymer Treated with CO2 Laser in Rat Middle Ear / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Long term success of the implant depends on the biocompatibility and biofunctionality. Biomaterial engineering and tissue engineering have provided important clue for choosing adequate biomaterials. Recently, laser application in reconstructive surgery has been developed in the fields of vascular, intestinal and nerve anastomosis. In the otologic field ear drum or polymer prostheses was treated with laser for reconstructive use. However, there was only a few attempts to find the morphological change and tissue reaction of laser treated material or tissue in otologic field. The aim of this study is to evaluate the biocompatibility and biofunctionality of laser treated polymer in the middle ear. MATERIALS AND METHODS: Ultra high molecular weight polyethylene (UMWP) was chosen. UMWP was inserted into middle ear of Sprague-Dawley rats. After 1, 2, 4 weeks, the bullae were removed and tissue reactions were observed with Hematoxilin-Eosin stain. RESULTS: In the animal study, more inflammatory cells were infiltrated on surface of laser treated UMWP compared with non-treated UMWP after 1 week. After 2 weeks, more macrophages and fibroblasts were found in the laser treated UMWP than in the nontreated UMWP. After 4 weeks, thin fibrous encapsulations were formed around the UMWP in both groups. In the laser treated UMWP, more pronounced destruction was found. CONCLUSION: These results indicated decrease of biofunctionality and acceptable biocompatibility of UMWP.

Sound Localization in Subjects with a Unilateral Hearing Loss according to Hearing Loss / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Sound localization in subjects with normal hearing is done by recognition of interaural difference of time, intensity and phase of sound source. Individuals with unilateral hearing losses, deprived of the binaural cues, are expected to have difficulty in localizing sound. The purpose of the research is to investigate the sound localizing ability in subjects with unilateral hearing losses to localize sound in horizontal plane by comparing with normal control group, and to know the effects of age, gender, stimulus type and hearing level. MATERIALS: Two groups of subjects participated in this study. The first group consisted of 60 normal hearing adults, in each age groups of 10 subjects, ranging from teens to sixties. The second group consisted of 50 subjects with unilateral hearing losses. METHODS: Sound localization ability was assessed by means of an array of eight loudspeakers positioned at the azimuth of 45 degrees each in the horizontal plane at a distance of 100 cm from the subject. The stimuli consisted of speech noise, narrow band noise centered at 500 Hz and 4000 Hz, pure tone of 500 Hz and 4000 Hz at the level of 45 dB HL for 5 seconds. RESULTS: 1) Speech noise was the most easily detected stimulus (p0.05). 3) The localization errors for speech noise increased significantly as hearing threshold increased in patients with unilateral hearing losses (p<0.001). CONCLUSION: The results suggest that speech noise is the most easily detected stimulus in directional discrimination test and that the ability of sound localization is degraded as hearing threshold is increased for patients with unilateral hearing losses.

Surgery in the Only Hearing Ear / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Management of chronic ear disease which affects the only hearing ear has been a topic of much debate since chronic ear disease runs the risk of damage to the inner ear. Cholesteatoma and uncontrolled otitis media can induce the sensorineural hearing loss, therefore, surgical removal of diseased tissue is sometimes unavoidable. MATERIALS AND METHOD: Tympanoplasty with mastoidectomy on the only hearing ears was performed in 9 patients. of whom four had cholesteatoma and five had mastoiditis. RESULTS: Compared to the preoperative air conduction hearing level, 3 cases showed improvement in the postoperative hearing level showed, whereas the remaining 6 cases did not show improvement.

A Case of Metastatic Renal Cell Carcinoma in Submandibular Gland / 대한이비인후과학회지

Renal cell carcinoma takes up 85 per cent of primary malignant renal tumors. It frequently metastasizes to the adrenal gland, lung, bone, liver and nephrectomy site but rarely to the head and neck area. When metastasizes to head and neck area, it involves the gingiva, tongue, palate, parotid gland, uvula, mandible, and lip. When tumors are found in the salivary gland consisting of clear cells, it is impartant to carry out differential diagnosis of various primary tumors with clear cell and metastatic renal cell carcinoma. Patients' medical history, review of system, and pathologic findings would be helpful factors in the differential diagnosis. In this paper, we report on a case of renal cell carcinoma which had metastasized to the psubmandibular gland after a radical nephrectomy.