Labyrinthine Fistula Secondary to Cholesteatoma: a Video Demonstration Joshua Michaels ‍ ‍ , Daniel Scholfield, Ashok Adams, Reshma Ghedia

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Department of Otolaryngology, DESCRIPTION Barts Health NHS Trust, London, Labyrinthine fistula is a defect of the bony laby- UK rinth of the petrous portion of the temporal bone. This can proceed to involve the membra- Correspondence to nous labyrinth.1 Causes include surgery, trauma, Joshua Michaels; joshuamichaels@ doctors.org. uk barotrauma, cholesteatoma and even noise exposure. This results in vertigo, hearing loss and 2 Accepted 16 May 2021 tinnitus. The fistula test is a bedside clinical examination which transmits pressure through the ear canal and through the fistula to the labyrinth resulting in vertigo and nystagmus. There is a conjugate deviation of the eyes away from the stimulated side with a corrective fast phase towards that side. In a lateral semicircular canal fistula, the nystagmus (fast phase) is accordingly horizontal and towards the affected ear. This can be elicited with digital tragal pressure or a pneumatic speculum. The pressure generated transmits to the inner ear, resulting in stimula- tion of the vestibular-ocular reflex and therefore the eyes move away but they attempt to revert to Figure 2 Axial T2 weighted imaging demonstrating 3 their original position. a large cholesteatoma abutting the right lateral We present the case of a 35-year -old man who semicircular canal (see arrow). previously underwent tympanoplasty and canal wall

down mastoidectomy 13 years ago. He presented to http://casereports.bmj.com/ the emergency department with a 6-week history of of meningism. Postauricular cellulitis changes were severe right-sided otalgia and mastoid pain associ- also present. His pure tone audiogram indicated ated with otorrhoea, debilitating vertigo and pulsa- mixed hearing loss. Intravenous antibiotic therapy tile tinnitus. was commenced and CT imaging was arranged Clinical examination revealed an unsteady gait, which identified a large, recurrent cholesteatoma Rhomberg’s positive sign and a positive fistula. His filling the right mastoidectomy cavity with a lateral facial nerve was intact and there were no features semicircular canal fistula and erosion of the tegmen. Subsequent MRI confirmed recurrent cholesteatoma (approximately 1.5 cm×2c m in the transverse

and anteroposterior dimension, respectively) and on September 25, 2021 by guest. Protected copyright. erosion of the tegmen mastoideum and contiguous

To cite: Michaels J, Scholfield D, Adams A, et al. BMJ Case Rep 2021;14:e242277. Figure 1 Non-Echo- Planar Diffusion-Weighted Figure 3 Intraoperative view of canal wall down doi:10.1136/bcr-2021- Imaging MRI with high signal confirming the sizeable mastoid cavity demonstrating the facial canal and left 242277 cholesteatoma (see arrow). semicircular canal (LSCC) fistula.

Michaels J, et al. BMJ Case Rep 2021;14:e242277. doi:10.1136/bcr-2021-242277 1 Images in… BMJ Case Rep: first published as 10.1136/bcr-2021-242277 on 26 May 2021. Downloaded from

Figure 4 Preoperative audiogram demonstrating significant air-bone gap conductive hearing loss of the right ear across all frequencies and similar air-bone gap conductive hearing loss of the left ear at low frequencies. Video 1 Video of a positive fistula test. tegmen tympani resulting in elevation of the dura overlying this prospective physicians and allied healthcare professionals with a region (figure 1). The cholesteatoma approximated the lateral useful educational tool for this sign which indicates bony erosion. genu of the lateral semicircular canal and had eroded parts of In the context of a painful, discharging ear, urgent referral to an otology specialist is required. the tympanic and mastoid segments of the facial canal (figure 2). The patient was listed for theatre 3 weeks later for a right Learning points revision mastoidectomy with obliteration. Findings included a large keratin filling cavity with loss of the posterior canal wall ►► Recurrent cholesteatoma can occur several years after initial and bone exposure over the left semicircular canal. Once the surgery. cholesteatoma and necrotic bone were removed, the defect was ►► Ear, nose and throat examination should always include reconstructed using temporalis fascia and autologous bone graft otomicroscopy to ensure an adequate view and clearance of (figure 3). keratin for preventing progression. Postoperatively, the patient had a gradual reduction of his ►► A positive fistula test is a sign of a large erosive dizziness which took 4 months to resolve. His ear pain and otor- cholesteatoma in the context of otalgia and otorrhoea and is rhoea resolved completely with improved hearing (figures 4 and an important clinical test to diagnose advanced disease and 5). He remains clinically well and undergoes regular follow-up. surgical urgency. The video clip demonstration of a positive fistula test (video 1) provides practitioners in both primary and secondary as well as

Contributors As author (JM), I would like to thank the support of our co-authors http://casereports.bmj.com/ (DS, RG and AA) at The Royal London Hospital for their concerted efforts towards producing this paper, both through data collection and patient record acquisition. The guidance throughout this project has been greatly appreciated. Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. Competing interests None declared. Patient consent for publication Obtained. Provenance and peer review Not commissioned; externally peer reviewed.

ORCID iD Joshua Michaels http://orcid. org/0000- 0001-8598- 3891 on September 25, 2021 by guest. Protected copyright.

REFERENCES 1 Rosito LPS, Canali I, Teixeira A, et al. Cholesteatoma labyrinthine fistula: prevalence and Figure 5 Postoperative audiogram demonstrating significant impact. Braz J Otorhinolaryngol 2019;85:222–7. 2 Deveze A, Matsuda H, Elziere M, et al. Diagnosis and treatment of perilymphatic fistula. improvements in the right-sided air-bone gap, particularly at the Adv Otorhinolaryngol 2018;81:133–45. mid-range frequencies. A similar audiogram is noted on the left as no 3 Minor LB. Labyrinthine fistulae: pathobiology and management. Curr Opin Otolaryngol operative treatment was performed on this side. Head Neck Surg 2003;11:340–6.

2 Michaels J, et al. BMJ Case Rep 2021;14:e242277. doi:10.1136/bcr-2021-242277 Images in… BMJ Case Rep: first published as 10.1136/bcr-2021-242277 on 26 May 2021. Downloaded from

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Michaels J, et al. BMJ Case Rep 2021;14:e242277. doi:10.1136/bcr-2021-242277 3