Endoscopic Stapedotomy (2:55)

Fixation of the stapes footplate results in conductive hearing loss. Stapedotomy is used to restore mobility to the stapes footplate by removing the stapes head and crura and replacing them with a prosthetic piston that connects the incus to the remaining stapes footplate. The procedure can be performed using either a surgical microscope or an endoscope. In this video we describe our technique for stapedotomy via an endoscopic approach.

After the external auditory canal is injected with local anesthetic an ear dissector is used to elevate the tympanomeatal flap from the temporal bone and facilitate visualization of the middle ear space with the endoscope. The stapes is then palpated and found to be fixed indicating that vibration of the tympanic membrane cannot be transmitted to the oval window through the ossicular chain. The malleus and incus have normal mobility on palpation.

Next the ear dissector is used to separate the incudostapedial joint. Then the stapes crura are incised using a CO2 laser in single pulse mode set at 4 W and 100 ms (OmniGuide). The capitulum and crura of the stapes are removed and the footplate remains in its anatomical position. The laser and an ear hook are then used to create a fenestration in the footplate for the stapes prosthesis. The prosthesis used in this case is a Nitinol piston (Grace Medical). The piston of the prosthesis is inserted into the fenestration created in the stapes footplate and the head of the prosthesis is maneuvered to surround the proximal end of the incus. The head has a heat-activated shape memory design which allows the laser to be used to secure the prosthesis to the incus. This completes the ossicular chain and restores mobility to the stapes footplate. Finally the tympanomeatal flap is returned to its anatomical position (1,2,3).

This procedure is indicated for the treatment of conductive hearing loss caused by a fixed stapes footplate (1,2).

This procedure is contraindicated for patients that are unable to tolerate anesthesia due to underlying medical comorbidities, are unable to lie flat for the procedure or are taking certain medications such as blood thinners. Otolaryngological contraindications include the diseased ear being the only hearing ear, patients with poor cochlear reserve characterized by severe sensorineural hearing loss or poor speech discrimination scores, patients in whom vestibular function is essential to their livelihood, or the presence of Meniere’s disease, tympanic membrane perforation or an active middle ear infection. The procedure is relatively contraindicated for patients with a history of multiple middle ear revisions without significant improvement in their symptoms (1).

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The patient is placed in a supine position with the head rotated so that the diseased ear is oriented slightly upwards. General anesthesia or monitored anesthesia care (MAC) can be used. MAC is beneficial in patients able to tolerate it because patients remain alert enough to follow instructions, answer questions and indicate if they are experiencing vertigo. General anesthesia is considered for pediatric patients, claustrophobic patients and patients with a history of adverse reactions to MAC. Preoperative antibiotics were not used in this case but may be used depending on surgeon preference. Paralytic agents are avoided if intraoperative facial nerve monitoring will be utilized (1,4).

History

Patients with fixation of the stapes footplate typically present with gradual conductive hearing loss in the affected ear(s). The most common etiology is otosclerosis although a heterogeneous group of other disorders can also result in stapes ankylosis. Otosclerosis can cause unilateral or bilateral conductive hearing loss and occurs twice as often in females as in males. The onset of symptoms usually occurs in the third decade of life but can also occur in later years or present as congenital conductive hearing loss in pediatric patients. Tinnitus may be present but vertigo is uncommon. Patients usually have a negative history for ear trauma or infection preceding their hearing loss. A strong family history of hearing loss is often present as otosclerosis is an autosomal dominant disease with variable penetrance. Otosclerosis can also be associated with osteogenesis imperfecta and present with the triad of hearing loss, spontaneous bone fractures and blue sclera known as Van der Hoeve syndrome (1,2,5).

Physical exam

The external auditory canal and tympanic membrane can be visualized via otoscopy or otomicroscopy. Pneumatic otoscopy can be utilized to rule out middle ear effusion or tympanic membrane perforation as causes of conductive hearing loss. In the presence of conductive hearing loss the Rinne test would show that bone conduction is greater than air conduction in the affected ear(s). If the disease is unilateral the Weber test would be expected to lateralize to the affected ear. Facial nerve function should also be assessed. Although the presence of stapes fixation may be presumed based on history, physical exam, and audiology findings a definitive diagnosis cannot be made until the ossicular chain is directly visualized during the procedure (1,2,6).

Audiology

Patients with conductive hearing loss should have a complete audiometric evaluation to determine air and bone conduction, speech thresholds and discrimination, and the presence or absence of an acoustic reflex. Tympanometry can be used to evaluate tympanic membrane function and middle ear pressure (1,2).

Imaging

CT scanning of the temporal bone may be used in certain patients to further evaluate suspected stapes fixation and to assess the anatomy of middle and inner ear structures (1,2).

Elevation of the tympanomeatal flap facilitates endoscopic visualization of the middle ear space. The malleus, incus, stapes, oval window, chorda tympani, and other middle ear structures are identified. The stapes is palpated to assess the mobility of the footplate. The stapedotomy and prosthesis placement are carried out as described in the Procedure section above (7).

Possible complications of stapedotomy include vertigo that is usually transient and persists only in rare cases, increased tinnitus particularly if hearing worsens after surgery, injury to the chorda tympani nerve resulting in temporary or permanent alteration in taste, perilymphatic fistula, reparative granuloma formation, and failure of the stapes prosthesis. Exceedingly rare complications include sensorineural hearing loss, injury to the facial nerve resulting in facial weakness, tympanic membrane perforation, and infection1,2.

Complication rates have been found to be very low in endoscopic ear surgery with minor intraoperative complications occurring in less than 5% of cases, early postoperative complications occurring in approximately 1% of cases, and delayed complications occurring in less than 1% of cases (12).

No conflicts to disclose.

1. Stapedotomy | Iowa Head and Neck Protocols. Accessed July 3, 2020. https://medicine.uiowa.edu/iowaprotocols/stapedotomy

2. Otosclerosis: Practice Essentials, History of the Procedure, Epidemiology. Accessed July 3, 2020. https://emedicine.medscape.com/article/859760-overview#a1

3. Instrument Set for Endoscopic Middle Ear Surgery E N T 1 3 7 4. 0 0 2 / 2 0 2 0-E. Accessed July 3, 2020. https://www.karlstorz.com/cps/rde/xbcr/karlstorz_assets/ASSETS/3448115.pdf

4. General Considerations of Otologic Surgery | Iowa Head and Neck Protocols. Accessed July 3, 2020. https://medicine.uiowa.edu/iowaprotocols/general-considerations-otologic-surgery

5. Etiology of hearing loss in adults - UpToDate. Accessed July 3, 2020. https://www.uptodate.com/contents/etiology-of-hearing-loss-in-adults?search=otosclerosis&source=search_result&selectedTitle=1~14&usage_type=default&display_rank=1#H21

6. Evaluation of hearing loss in adults - UpToDate. Accessed July 3, 2020. https://www.uptodate.com/contents/evaluation-of-hearing-loss-in-adults?search=otosclerosis&topicRef=6844&source=see_link

7. Anschuetz L, Presutti L, Marchioni D, et al. Discovering middle ear anatomy by transcanal endoscopic ear surgery: A dissection manual. J Vis Exp. 2018;2018(131):56390. doi:10.3791/56390

8. Hsu YC, Kuo CL, Huang TC. A retrospective comparative study of endoscopic and microscopic Tympanoplasty. J Otolaryngol - Head Neck Surg. 2018;47(1). doi:10.1186/s40463-018-0289-4

9. Wick CC. Endoscopic Stapedotomy - CSurgeries. Accessed July 3, 2020. https://www.csurgeries.com/video/endoscopic-stapedotomy/

10. Preyer S. Endoscopic ear surgery – a complement to microscopic ear surgery. HNO. 2017;65(1):29-34. doi:10.1007/s00106-016-0268-x

11. Catapano D, Sloffer CA, Frank G, Pasquini E, D’Angelo VA, Lanzino G. Comparison between the microscope and endoscope in the direct endonasal extended transsphenoidal approach: Anatomical study. J Neurosurg. 2006;104(3):419-425. doi:10.3171/jns.2006.104.3.419

12. Marchioni D, Rubini A, Gazzini L, et al. Complications in endoscopic ear surgery. Otol Neurotol. 2018;39(8):1012-1017. doi:10.1097/MAO.0000000000001933