The Effect of the Angle and Length of the Eustachian Tube on the Success Rate of Cartilage Type 1 Tympanoplasty.

OBJECTIVES: To explore the relationships between the angle and length of the eustachian tube (ET) (the ETa and the ETl) and the success rates of type 1 tympanoplasty.

STUDY DESIGN: A retrospective clinical chart review.

METHODS: In total, 160 patients (81 females and 79 males; average age, 37.12 ± 12.46 years; age range: 18-65 years) who underwent cartilage type 1 tympanoplasty were included. Demographics and anatomical outcomes were recorded. The patients were divided into 2 groups in terms of anatomical success. The average ETa and ETl values of each group were measured on computed tomography images using a multiplanar reconstruction technique, and compared. A P value <0.05 was considered to reflect statistical significance.

RESULTS: In group A, the ETa of diseased ears was 27.74 ± 12.06° in males and 21.87 ± 7.58° in females. In group A, the ETa of normal ears was 27.53 ± 4.15° in males and 22.25 ± 4.67° in females. In group B, the ETa of diseased ears was 28.85 ± 6.19° in males and 22.91 ± 5.65° in females. In group B, the ETa of normal ears was 27.71 ± 5.23° in males and 23.72 ± 6.20° in females. In group A, the mean ETl of diseased ears was 42.1 mm (28.9-45.1) in males and 38.2 mm (31.0-44.7) in females. In group A, the mean ETl of normal ears was 41.9 mm (29.2-45.8) in males and 37.4 mm (30.5-44.1) in females. In group B, the mean ETl of diseased ears was 40.8 mm (30.2-47.4) in males and 37.9 mm (31.8-45.2) in females. In group B, the mean ETl of normal ears was 41.6 mm (30.0-45.0) in males and 39.1 mm (30.0-43.7) in females. In group A, the ETa value of diseased ears did not differ between females and males, but in normal ears the ETa was higher in males than females (P =0.002 and P <0.05, respectively). In group B, no difference was evident between the ETa values of normal and diseased ears (P >0.05). No difference in the ETl values of diseased and normal ears, in either group, was apparent between females and males (both P >0.05).

CONCLUSION: Neither the ETa nor the ETl affected the success rate of cartilage type 1 tympanoplasty. Further studies with larger numbers of patients are needed to compare anatomical outcomes after placement of various graft types and the effects of anatomical features of the ET on the success rate of type 1 tympanoplasty.