Short Term Follow-up of Hearing Changes according to Insertion Site of Temporalis Muscle Fascia in Type I Tympanoplasty / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: There are two types of methods in the underlay technique that are employed according to the graft insertion site. The purpose of this study is to evaluate the short term follow-up results of air-bone conduction threshold changes according to the insertion of temporalis muscle fascia to medial and lateral side of malleus in type I tympanoplsty with simple mastoidectomy. MATERIALS AND METHOD: 72 patients with perforated tympanic membrane over the half size in pars tensa were operated in type I tympanoplasty with simple mastoidectomy. Patients were divided into two groups according to the insertion of fascia of temporalis muscle to either i) lateral side of the malleus (group A, 32 cases) or ii) medial side of the malleus (group B, 40 cases). Each group was divided into three subgroups according to size of perforation in the tympanic membranes, ranging from moderate, large, to total. Difference in the air-borne conduction threshold changes between the first preoperative and postoperative year was analyzed for each group. RESULTS: The differences in the pre and postoperative air-bone conduction gap (ABG) between the group A and B were 14.4+/-7.1 dB, 10.4+/-6.2 dB, respectively. There was no statistical difference between the two groups (p>0.05). The pre and postoperative ABG differences for different sizes of perforation in the tympanic membrane in group A were 17.5+/-12.2 dB (moderate), 14.1+/-7.4 dB (large), 14.5+/-8.5 dB (total), and in group B were 9.5+/-4.8, dB (moderate), and 9.3+/-7.2 dB (large), and 12.0+/-7.1 dB (total). There was no statistical difference between the subgroups of the same group (p>0.05). The pre and postoperative bone conduction threshold of group A decreased at 250, 500, 1000, and 2000 Hz but increased at 3000, 4000 Hz. The threshold of group B decreased at all frequency. Postoperative reperforations were observed in just 2 cases of the group B. One case was observed at 5 postoperative months in the large perforation group, and the other case was observed at 15 months in the total perforation group, with the former case healing spontaneously at 6 months. CONCLUSION: The results suggest that the two methods of underlay technique could be selected properly by location of perforation, middle ear anatomy and its pathological state, and continuity of ossicles, as well as per operator's preference. When the perforation is located at the anterior, anterosuperior and anteroposterior portion of tympanic membrane, the tympanic membrane is thickened severely so the boundary becomes uncertain between the middlear mucosa and the tympanic membrane. The insertion of fascia to lateral side of malleus is therefore recommended.