Effectiveness of Transmastoid Plugging for Semicircular Canal Dehiscence Syndrome

Abstract

Objectives (1) Evaluate changes in subjective symptoms in patients following transmastoid canal plugging for superior semicircular canal dehiscence (SSCD) syndrome. (2) Quantify changes in hearing in patients who have undergone transmastoid canal plugging for SSCD syndrome. Study Design Case series with chart review. Setting Single tertiary care institution. Subjects and Methods We retrospectively reviewed patients with SSCD who underwent repair with canal plugging via a transmastoid approach between January 2012 and January 2017. Symptom severity was assessed prospectively (autophony, sound/pressure-induced vertigo, disequilibrium, aural fullness, and pulsatile tinnitus) and after surgery. Pure-tone and speech audiometry were measured before and after surgery. Two-sided Wilcoxon rank-sum tests were used to evaluate changes in subjective symptoms and audiometric outcomes. Results Seventeen patients (19 ears) met inclusion criteria. The superior canal was successfully plugged via the transmastoid approach in all cases. Patients reported a statistically significant improvement in autophony, vertigo, aural fullness, and pulsatile tinnitus ( P < .01), without significant improvement in disequilibrium rating ( P = .06). There were no changes noted in pure-tone average or word recognition score; however, there was a statistically significant improvement in air-bone gap at 250 Hz of 10.9 dB ( P = .04) with 12.9-dB improvement in air conduction thresholds ( P = .02) and no difference (0.9 dB, P = .9) in bone conduction thresholds. Conclusion In our study, patients with SSCD demonstrated excellent hearing outcomes and resolution of most otologic symptoms after surgical repair. Transmastoid canal plugging, which has been described to date only in smaller case series, is a safe and effective alternative to the traditional middle cranial fossa approach.

A new landmark for superior semicircular canal: Spine of Henle

“…[3,4,7] Later on, the transmastoid approach was developed to avoid a craniotomy and temporal bone retraction, thereby, reducing morbidity and hospital stay. [5,8,9] In 2001, Brantberg et al [8] described the plugging of the superior SCC using a transmastoid approach. During surgery, they initially identified the lateral SCC and used it as a landmark for the exposure and blue lining of the superior SCC.…”

“…Since the transmastoid approach obviates a craniotomy and experienced otologists are familiar to this approach, many case series via transmastoid approach have been reported to date with good auditory and vestibular results. [5,[9][10][11] As it has become more popular in recent years, the identification of the superior SCC has come to the front. However, lateral SCC is the only landmark used for the superior SCC and, in case of sclerotic mastoid bones, it can be difficult to localize the superior SCC.…”

“…The treatment options of this syndrome includes middle fossa craniotomy and repair of fistula, transmastoid superior canal occlusion, and transcanal oval and round window reinforcement. [3][4][5][6] While performing the transmastoid superior canal occlusion, the identification of the superior SCC is one of the major steps of this surgery. The superior SCC is not routinely identified during mastoidectomies and this procedure can be difficult.…”

Superior Semicircular Canal Dehiscence

“…Bu çalışmada, transmastoid yaklaşımın orta fossa yaklaşımına göre daha güvenli ve etkili bir alternatif olduğu belirtilmektedir. 33 Yapılan pilot bir çalışmada, transmastoid onarım ile orta fossa kraniotomi ile onarım karşılaştırılmıştır. İşitme sonuçlarında uzun sürede fark gözlenmemiştir.…”

Hearing Outcomes after Transmastoid Plugging of Superior Canal Dehiscence

“…Early feasibility studies on hearing preservation after canal plugging were observed by Parnes and McClure among guinea pigs [Parnes and McClure, 1985]. Among human-beings, the preservation of hearing thresholds has been observed in patients undergoing canal plugging of the posterior canal through the transmastoid approach and the superior canal by the middle cranial fossa approach [Agrawal and Parnes, 2001;Banakis Hartl and Cass, 2018;Beyea et al, 2012;Lundy et al, 2011;Niesten et al, 2013;Powell et al, 2016;Van Haesendonck et al, 2016;Yamauchi et al, 2017] as well as the superior canal by middle cranial fossa approach [Ward et al, 2012]. Generally, surgery has a positive impact of the symptoms of SCDS.…”