Preservation of Auditory Function by Plugging Using Underwater Endoscopic Ear Surgery for Superior Canal Dehiscence Syndrome

By June 7, 2019

Kawamura, Yoshinobu1,2; Yamauchi, Daisuke1; Honkura, Yohei1; Ikeda, Ryoukichi2; Miyazaki, Hiromitsu2; Hara, Yosuke1; Kobayashi, Toshimitsu2; Kawase, Tetsuaki3; Katori, Yukio1
1 Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Miyagi, Japan;
2 Sen-En Rifu Otological Surgery Center, Miyagi, Japan;
3 Graduate School of Biomedical Engineering, Laboratory of Rehabilitative Auditory Science/Graduate School of Medicine Department of Audiology, Miyagi, Japan.

The most appropriate technique for management of superior canal dehiscence syndrome (SCDS) has been disputed over the past decade. Transmastoid plugging seems to be reliable, although it is associated with a risk of inner-ear damage. Recently we have succeeded in developing underwater endoscopic ear surgery (UWEES) for plugging of superior semicircular canal dehiscence while preserving auditory function by avoiding unexpected introduction of air into the labyrinth.

– Patients: 
Six cases of SCDS treated at Tohoku University Hospital and Sen-En Rifu Otological Surgery Center.
– Intervention: Plugging with the UWEES technique. The mastoid cavity was filled completely with perfusate delivered via an Endo-scrub lens cleaning sheath (Medtronic) covering a 0-degree 2.7-mm-diameter high-definition endoscope (Storz), as reported previously. Artificial cerebrospinal fluid (ARTCEREB, Otsuka) was used as the perfusate, except for one case using saline. The superior semicircular canals were identified and opened by drilling with a 1-2-mm curved diamond bur (IPC System). Plugging was accomplished using autologous fascia reinforced with fibrin glue, bone wax, and bone paste or artificial bone paste (BIOPEX, HOYA Technosurgical).

– Main Outcome Measures: 
All cases of SCDS were treated successfully by plugging with UWEES.
– Results: The membranous labyrinth of the semicircular canal and the portion of dehiscence were identified clearly in all cases. Despite the relatively long exposure of the canal, bone conduction thresholds were well preserved. Auditory threshold levels were improved at lower frequencies with a decrease of the air-bone gap in most cases. Vertigo and dizziness were slight in all cases.

For SCDS we recommend UWEES for plugging with preservation of auditory function.