Labyrinthitis With Endolymphatic Hydrops Revealed by Imaging Analysis in a Case With Severe Postoperative Complications Following Stapes Surgery

概要

Case Report
A 32-year-old man visited our hospital 3 months after stapes surgery, due to postoperative hearing loss in the right ear for bilateral otosclerosis at another hospital. He had undergone Fisch’s reversal steps stapedotomy, in which the prosthesis was introduced after perforation of the footplate following removal of the superstructure. He experienced vertigo and hearing loss in the operated ear on the day following surgery, progressing to severe sensorineural hearing loss from the fifth postoperative day after intravenous steroid treatment for possible inner ear damage. The patient had suffered from conductive hearing loss in both ears and experienced no symptoms related to inner ear disturbances preoperatively, such as vertigo and fluctuating sensorineural hearing loss (Fig. 1). Computed tomography (CT) performed 6 months after the surgery revealed that the inserted piston was in an appropriate position, although the semicircular canals were ossified (Fig. 2). On magnetic resonance imaging (MRI) performed 4 h after intravenous injection of gadolinium hydrate, high enhancement and significant endolymphatic hydrops (EH) were observed in the cochlea of the operated ear, and there were no lymphatic spaces visible in the vestibule or the semicircular canals (Fig. 3). EH was also found in the cochlea, vestibule and semicircular canals on the non-operated side. He did not request hearing aids to improve his hearing difficulty, and only his hearing on the contralateral side was subsequently followed up.

Discussion
Stapes surgery for otosclerosis is a surgical procedure with a high success rate, although vertigo and sensorineural hearing loss (SNHL) are serious postoperative complications (1). Fisch’s reversal steps stapedotomy was performed in the present case to reduce the risk of a footplate incident leading to inner ear damage (2), and postoperative CT revealed that the inserted piston was in an appropriate position. EH associated with otosclerosis has been previously reported (3). Recent MRI studies have demonstrated that the presence of EH in ears with otosclerosis and ears with EH in the vestibule are associated with long periods of dizziness postoperatively, indicating that the preoperative presence of EH in the vestibule on MRI might be a high-risk factor for complications following stapes surgery (4, 5).

High enhancement in the cochlea and ossification in the semicircular canals suggested the occurrence of severe inflammation in the operated ear in the present case. Significant EH in the cochlea in the operated ear might have represented secondary EH due to labyrinthitis, although EH was also detected on the non-operated side. The imaging findings suggest that in cases with an abnormally extended membranous labyrinth due to EH, the inserted piston might unexpectedly traumatize the labyrinth, which might result in severe labyrinthitis and postoperative complications following a standard stapes procedure. A history of vertigo or fluctuating hearing loss suggestive of inner ear disease should be elicited preoperatively, since this can lead to unexpected complications after stapes surgery.

この論文で使われている画像