An endoscopic approach to stapes surgery allows for enhanced visualization of the ossicular chain and oval window. Additionally, endoscopy of the middle ear has been especially useful in diagnosing ossicular malformations, perilymphatic fistulas, and ossicular fixation.
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September 2020
Surgery under general anesthesia was performed by two surgeons at two institutions. Patients underwent either stapedotomy or stapedectomy, which was dependent on the intraoperative findings, prior surgical history, and surgeon preference. The techniques for endoscopic stapedotomy and stapedectomy have been previously described (Otolaryngol Head Neck Surg. 2016;154:1093–1098. Curr Opin Otolaryngol Head Neck Surg. 2016;24:388–394. Otolaryngol Clin North Am. 2018;51:415–428). Patients who underwent laser stapedotomy received an Eclipse nitinol piston prosthesis (Grace Medical, Memphis, Tenn.), whereas those who underwent a laser stapedectomy received a titanium notched bucket handle prosthesis (Grace Medical) in conjunction with a perichondrial graft to seal the oval window after partial or total removal of the stapes footplate. In cases of incus necrosis precluding prosthesis placement on the incus, an Eclipse nitinol malleus to fenestra piston prosthesis (Grace Medical) was used.
Statistical analyses were performed with GraphPad Prism 7.0 (GraphPad Software, La Jolla, Calif.). Continuous variables were reported as medians with ranges when not normally distributed. Mann-Whitney testing was applied to medians with nonparametric values, with all tests two sided and P values less than 0.05 considered statistically significant.
Fig. 1. Intraoperative findings. (A) Necrosis of long process of incus (arrowhead) resulting in prosthesis displacement from stapes footplate (*) (patient 2). (B) Prosthesis displaced to posterior rim of footplate (*) (patient 1). (C) Prosthesis displacement (removed) with prolapsed facial nerve (white arrow) and prominent bony overhang (black arrow), which was drilled to allow for prosthesis placement during revision surgery (patient 3). (D) Short wire loop prosthesis (black arrow) making poor contact with stapes footplate (*) (patient 4).
Results
Patient Characteristics
Between 2014 and 2017, a total of six adult patients with median age of 53.2 years (range, 19.1–82.6 years) underwent total endoscopic revision stapes surgery. All patients had an initial diagnosis of otosclerosis prior to primary stapes surgery, which in all cases was performed by a different surgeon. One patient had a history of three prior stapes surgeries of the ipsilateral ear, whereas the remaining patients had a history of a single prior stapes surgery. Prior to revision surgery, four (66.7%) patients reported tinnitus, whereas none reported dizziness. Patients 3 and 6 had a history of tobacco use. Three patients had preoperative imaging; the cause of failure was accurately diagnosed by computed tomography (CT) scan in one case (patient 1).
Surgical Technique
Each patient underwent transcanal totally endoscopic ear surgery (TEES) with the use of 0° and/or 30° endoscopes (100% and 33.3%, respectively). The endoscopic approach to the middle ear, including TM elevation, has been previously described (Otolaryngol Clin North Am. 2018;51:415–428). For revision stapes surgery, the integrity and mobility of the ossicular chain and prior prosthesis was first evaluated with palpation and visual inspection for bony erosion. Next, the prosthesis was evaluated for appropriate placement, size, and contact with the stapes footplate or graft overlying the oval window in the case of previous stapedectomy. Finally, the oval window was evaluated for progressive otosclerotic plaque, prolapsed facial nerve, or prominent bony overhang that could prevent ideal placement of a new prosthesis. Once the cause of failure was identified and addressed, the new prosthesis was placed using either a stapedotomy or stapedectomy technique.
Audiologic Outcomes, by Patient
| AC PTA, dB HL | BC PTA, dB HL | ABG, dB HL | SDS, % | |
|---|---|---|---|---|
| Patient 1 | ||||
| Preoperative | 47.5 | 16.3 | 31.3 | 100 |
| Postoperative | 33.8 | 20 | 13.8 | 90 |
| Change | -13.7 | 3.7 | -17.5 | -10 |
| Patient 2 | ||||
| Preoperative | 82.5 | 38.8 | 43.8 | 90 |
| Postoperative | 35 | 18.8 | 16.3 | 100 |
| Change | -47.5 | -20 | -27.5 | 0 |
| Patient 3 | ||||
| Preoperative | 95 | 66.3 | 28.8 | 22 |
| Postoperative | 75 | 66.3 | 8.8 | 42 |
| Change | -20 | 0 | -20 | 20 |
| Patient 4 | ||||
| Preoperative | 57.5 | 22.5 | 35 | 100 |
| Postoperative | 16.3 | 5 | 11.3 | 100 |
| Change | -41.2 | -17.5 | -23.7 | 0 |
| Patient 5 | ||||
| Preoperative | 65 | 25 | 41.7 | 100 |
| Postoperative | 63.8 | 21.3 | 42.5 | 100 |
| Change | -1.2 | -3.7 | 0.8 | 0 |
| Patient 6 | ||||
| Preoperative | 90 | 65 | 25 | 68 |
| Postoperative | 91.3 | 70 | 21.3 | CNE |
| Change | 1.3 | 5 | -3.7 | - |
| AC = air conduction; BC = bone conduction; CNE = could not examine; HL = hearing level; PTA = pure-tone average; SDS = speech discrimination score. |
AC = air conduction; BC = bone conduction; CNE = could not examine; HL = hearing level; PTA = pure-tone average; SDS = speech discrimination score.
Intraoperative Findings
Three patients (50%) had evidence of prior scutum removal. An additional two cases with an intact scutum required removal for visualization and instrumentation. The chorda tympani nerve was previously transected in two cases, required manipulation without transection in two cases, and was not manipulated in the remaining two cases.
Intraoperative endoscopic inspection of the middle ear revealed a displaced, loose, or missing prosthesis in all cases. Incus necrosis was noted in two cases (33.3%). Four patients (66.7%) underwent laser stapedotomy; one patient underwent laser stapedectomy; and one patient required an oval window drill-out due to extensive oval window involvement of otosclerosis. One case (patient 5) revealed malleus fixation, which was resolved with the release of an ossified anterior malleolar ligament and a medial malleus bar using a laser and right-angle pick. Surgical technique and treatment of the oval window were dependent on both middle ear anatomy and surgeon preference. The median operative time was 111 minutes (range, 84–154 minutes). There were no instances of intraoperative complications including TM perforation, floating footplate, facial nerve injury, or incus dislocation. All patients were discharged on the day of surgery without readmissions.
Audiologic and Surgical Outcomes
The median audiologic follow-up was 7.4 months (range, 1.5–33.3 months). At the time of last follow-up, the median air–bone gap (ABG) was 15 dB HL (range, 8.8–42.5 dB HL), improved from 33.1 dB HL (range, 25–43.4 dB HL) preoperatively (P < 0.0306). Five of six patients had a reduction in the ABG, whereas one patient (patient 5) had an increase of 0.8 dB. Overall, 66.7% of patients had a closure of the ABG to ≤20 dB.
Patient 6 experienced a temporary 20 dB SNHL hearing loss and vertigo one week after surgery. This patient was diagnosed with labyrinthitis and treated with a high-dose prednisone taper followed by resolution of symptoms and SNHL within three weeks. Postoperatively, patient three, who intraoperatively had manipulation but preservation of the chorda tympani nerve, reported dysgeusia that resolved within three weeks. Overall, there were no instances of permanent postoperative SNHL >15 dB HL, facial nerve injury, or TM perforations.