The resilience of the inner ear—vestibular and audiometric impact of transmastoid semicircular canal plugging

Abstract

Background Certain cases of superior semicircular canal dehiscence or benign paroxysmal positional vertigo can be treated by plugging of the affected semicircular canal. However, the extent of the impact on vestibular function and hearing during postoperative follow-up is not known. Objective To evaluate the evolution of vestibular function and hearing after plugging of a semicircular canal. Methods Six patients underwent testing before and 1 week, 2 months, and 6 months after plugging of the superior or posterior semicircular canal. Testing included caloric irrigation test, video Head Impulse Test (vHIT), cervical and ocular Vestibular Evoked Myogenic Potentials (VEMPs) and audiometry. Results Initially, ipsilateral caloric response decreased in all patients and vHIT vestibulo-ocular reflex (VOR) gain of each ipsilateral semicircular canal decreased in 4/6 patients. In 4/6 patients, postoperative caloric response recovered to > 60% of the preoperative value. In 5/6 patients, vHIT VOR gain was restored to > 85% of the preoperative value for both ipsilateral non-plugged semicircular canals. In the plugged semicircular canal, this gain decreased in 4/5 patients and recovered to > 50% of the preoperative value. Four patients preserved cervical and ocular VEMP responses. Bone conduction hearing deteriorated in 3/6 patients, but recovered within 6 months postoperatively, although one patient had a persistent loss of 15 dB at 8 kHz. Conclusion Plugging of a semicircular canal can affect both vestibular function and hearing. After initial deterioration, most patients show recovery during follow-up. However, a vestibular function loss or high-frequency hearing loss can persist. This stresses the importance of adequate counseling of patients considering plugging of a semicircular canal.

Changes of Vestibular Symptoms in Menière's Disease After Triple Semicircular Canal Occlusion: A Long-Term Follow-Up Study

“…A major concern with TSCO is postoperative HL. Stultiens et al (27) assessed the postoperative hearing of patients with a semicircular canal plug and found a difference from the preoperative hearing level of <10 dB HL at the 6-month followup. Their study included stage 1-2 patients.…”

Effect of cochlear implantation on vestibular function in children: A scoping review

“…For example, cVEMP and oVEMP responses measured with bone-conduction showed less alteration after cochlear implantation than those tested with air-conduction ( 48 ). This implies that, for example, a post-operative hematotympanum or a recently performed mastoidectomy may impact the outcomes of VEMPs and possibly also the caloric test ( 49 ). One of the included studies in this review implied that vestibular function can restore within weeks after implantation ( 34 ).…”

Occlusion of two semicircular canals does not disrupt normal hearing in adult mice

“…It has been known for a long time that surgically obstructing posterior semicircular canal is an effect way to treat benign positional vertigo ( 8 – 10 , 13 , 23 ). The main risk of such an operation was the potential damage to hearing.…”

“…However, SCO has also been reported to cause hearing loss in some patients, while no hearing loss has been observed in other patients (9,10). The controversy surrounding SCO's potential side effects on auditory function has limited the treatment's availability to patients with intractable vertigo attacks, and have moderate to severe hearing loss (9)(10)(11)(12)(13). Therefore, determining whether SCO is safe for maintaining auditory function is essential to further expand SCO's availability for patients with other forms of vertigo, such as vestibular peripheral vertigo.…”