真珠腫性中耳炎に対する術式の検討

有茎骨膜骨弁による外耳道再建

抄録

From January 1985 to September 1990, at the Medical College of Oita, we performed 100 tympanoplasties for patients with chronic otitis media with cholesteatoma. Sixty cases in this series were subjected to the reconstruction of the external auditory canal with the pedicled periosteo-osteal flap made on the mastoid after canal down tympanoplasty. In 12 cases, canal up tympanoplasy was performed, transcanal atticotomy was in 16 cases, and canal down tympanoplasty was in 12 cases. All cases were followed up for at least 12 months after surgery.
Recurrent cholesteatoma was found in two cases of this series. Both of the recurrent cases were children with attic type of cholesteatoma. One of them was a 13-year-old boy from the reconstruction group, and the other was a 10-year-old boy from the canal up group. The recurrence of cholesteatoma was not significantly different among those 4 procedures.
Mean duration of the re-epithelization of the postoperative canal wounds in the reconstruction group (30 days) was similar to those values of the canal up group (22 days) and the atticotomy group (33 days) and significantly shorter than that of the canal down group (74 days).
After reconstruction of the canal wall with the pedicled periosteo-osteal flap, 48 canals (80%) showed normal appearance. Eight canals (13%) were slightly expanded by a backwards shift of the bone graft, and 2 canals (3%) were slightly narrowed. However, they required no postoperative treatments, such as local cleaning or crust removal. Retraction pocket with recurrent cholesteatoma was found in one case (2%). Only one case required the surgical removal of the bone graft because of infection and necrosis.
Hearing improvement after surgery was achieved in 27 cases (45%) of the reconstruction group, 5 cases (42%) of the canal up group, 8 cases (50%) of the atticotomy group and 2 cases (17%) of the canal down group. Although the stapedial superstructure was frequently damaged by cholesteatoma in the reconstruction group, the postoperative hearing improvement of this group was a satisfactory result in comparison with that of the canal up group.
These findings suggest that the reconstruction of the canal wall defect after canal down tympanoplasty solves so-called ‘cavity problems’ attributed to the canal down procedure and improves postoperative hearing by rebuilding the physiological structure of the external auditory canal and middle ear cleft. For the reconstraction of the canal wall defect, the pedicled periosteo-osteal flap is a useful material because it is a viable allograft receiving blood supply via the periosteal pedicle and well fuses with surrounding tissues. Since it is easy to make the bony graft on the mastoid cortex and does not require extensive surgery, this technique is effective for the reconstruction of the canal wall defect after canal down procedure.