Otosclerosis Treatment & Management

As with conductive hearing losses of other etiologies, hearing aids are usually helpful. Fluoride supplementation has met with variable response and is used sporadically for labyrinthine otosclerosis. It has also been used for postoperative medical management of obliterative otosclerosis.

Approaches to surgical management of otosclerosis include total stapedectomy, partial stapedectomy, and stapedotomy. Hearing improvement can be achieved through surgery for congenital stapes footplate ankylosis with a concomitant ossicular chain anomaly. Final hearing levels after surgery can be influenced by sensorineural impairment. ^[12]

A history of significant nausea, emesis, or severe vertigo from previous surgical procedures, including a stapes operation on the contralateral ear, is a strong indicator that the patient will have a similar reaction after a stapes operation. Use of a transderm scopolamine patch placed postauriculary on the contralateral side the night prior to surgery imparts significant antiemetic properties.

The patient should be counseled as to the surgeon's specific postoperative instructions, including avoidance of nose blowing, sneezing, and allowance of water into the ear canal. Documenting the risks of a stapes operation is helpful from a medicolegal standpoint; the risks of such surgery include, but are not limited to, permanent and complete hearing loss, facial paralysis, permanent or temporary taste alterations, tinnitus, vertigo, tympanic membrane perforation, infection, and failure of the surgery to improve hearing.

Primary procedures may be performed under general or local anesthesia with sedation. ^[13] The transcanal approach is almost always used.

A tympanomeatal flap is raised along the posterior external auditory canal. The ossicles are immediately identified and palpated to verify movement. Palpation of the malleus should elicit movement all the way to the incudostapedial joint. Palpation of the lenticular process of the incus indicates fixation of the stapes superstructure. Delicate palpation prevents an inadvertent immobilization of the stapes. See the images below.

Mobilizing the chorda, which usually involves careful curettage of the scutum and partially translocating the nerve out of its bony canal, is often necessary. Additional bone from the scutum is removed to allow positive identification of the pyramidal process, stapedial footplate, and the tympanic segment of the facial nerve (see image below). Attention is directed at the facial nerve to ensure that the nerve is not prolapsed onto the footplate. Presence of such an anomaly may require termination of the procedure at this point.

The prosthesis is sized by measuring the distance from the footplate to the medial surface of the incus. The incudostapedial joint is disarticulated sharply in an anterior-posterior plane, using the stapedial tendon to provide stabilization of the stapes. See the image below.

The stapedial tendon is divided with either scissors or laser. See the image below.

In stapedectomy operations, a control hole is made in the midportion of the footplate with a straight pick prior to disarticulation of the incudostapedial joint. The stapes superstructure may be downfractured by exerting delicate force in a superior-to-inferior plane just medial to the capitulum of the stapes. The control hole is widened and the footplate bisected with a 0.3-mm right-angle pick. The posterior one third of the footplate may be removed to perform a partial stapedectomy. A total stapedectomy involves removal of the entire footplate with a right-angle pick. A small fenestra stapedectomy involves widening the control hole to 0.6-0.8 mm. Whichever stapedectomy technique is used, the oval window opening is now covered with a tissue autograft composed of either fascia, vein, or perichondrium. A prosthesis may now be placed between the oval window and the incus. See the image below.

In a stapedotomy procedure, the posterior crus of the stapes is divided with either the laser or crurotomy scissors. The stapes superstructure is downfractured and removed. A hole is made in the footplate using either the laser or a microdrill. A tissue graft is placed over the oval window opening when a bucket handle prosthesis is used, or the oval window may remain uncovered when other types of prostheses are used. A prosthesis is chosen based on the surgeon's experience and comfort. A blood seal can be created by abrading the mucosa of the superior promontory and allowing blood to ooze onto the prosthesis-oval window interface. This may prevent perilymphatic fistulization. See the images below.

Perilymphatic fluid suctioning should be avoided to minimize postoperative vertigo and cochlear damage. The malleus is carefully palpated to ensure movement of the ossicles all the way through the prosthesis. Visualization of a round window reflex confirms the presence of an intact ossicular mechanism.

The tympanomeatal flap is replaced over the posterior external auditory canal and the ear canal is filled with either an antibiotic ointment or antibiotic solution-treated Gelfoam.

A study by Vincent et al indicated that stapedotomy can be safely and effectively performed in children with juvenile otosclerosis. The study included 34 pediatric patients with otosclerosis (41 primary stapedotomies total), with the postoperative air-bone gap closure being 10 dB or less in 93% of patients and to within 20 dB in 98% of patients. ^[14]

Surgery is typically performed on an outpatient basis. Unless experiencing significant vertigo or emesis, patients are usually safe to leave the hospital within a few postoperative hours. Bedrest is necessary only in the immediate postoperative period.

The first postoperative visit is usually scheduled after 2 weeks, which allows time for the tympanomeatal flap to heal in place. The canal may be débrided at this time. Cotton balls are placed in the meatus 2-3 times per day to collect discharge from the canal over the first several days after the surgery. Postoperative audiometrics are typically performed 3-6 weeks after surgery.

Sensorineural hearing loss occurs in only 0.2% of cases, but patients should be informed of a 2% chance of additional hearing loss in the operated ear and less than a 1% chance of complete loss of residual hearing. This complication has an unclear etiology. A Weber tuning-fork test that lateralizes away from the operative ear in the immediate postoperative period is an indication of a sensorineural hearing loss provided that the contralateral ear does not also have a significant conductive hearing loss. If sensorineural hearing loss is suspected, steroid therapy is initiated and tapered over a 10-day course. Prednisone 1 mg/kg/d divided into 2 doses over the first 7 days with a rapid taper is the author's preferred dosing regimen.

Tinnitus may be more pronounced postoperatively, especially if hearing worsens following surgery.

Facial nerve palsy is a devastating, and fortunately rare, complication. In a series of 700 stapedectomies, only 2 patients had facial weakness; both were of delayed onset (around postoperative day [POD] 5), and both completely resolved within 2 weeks with steroid administration.

Significant vertigo affects approximately 5% of patients and usually is transient and brief, persisting only in rare cases. Management is typically supportive only, unless symptoms suggest perilymphatic fistula. (A prospective observational study by de Vilhena et al reported a higher rate of vertigo. The study, of 140 patients with otosclerosis who underwent stapedial surgery, found that, while 12 patients [8.6%] reported having vertigo prior to surgery and no vertigo after the operation, 36 patients [25.7%] who had no vertigo before surgery reported having vertigo 4 months after the procedure. ^[15] )

A retrospective study by Wedel et al that looked at 93 stapedotomies in patients with otosclerosis found that postoperatively, patients most frequently complained of transient vertigo (37%). ^[16]

Perilymphatic fistula occurs in 3-10% of patients poststapedectomy and is characterized by fluctuating sensorineural hearing loss and vertigo. Incidence of this complication has declined concomitantly with the decline of total stapedectomies. Laser use and abandonment of absorbable gelatin sponge have further decreased this complication.

Taste disturbance occurs in about 9% of patients. Most authors advocate sectioning the chorda tympani if it is intraoperatively found stretched or otherwise injured to decrease the incidence further.

The above-mentioned study by Wedel and colleagues reported that the most common permanent complication in stapedotomy was taste disturbance (14%). ^[16]

Tympanic membrane perforation is rare, and if it occurs during surgery, a fascial graft repair can be performed. This was supported by a retrospective study by Luryi et al that suggested that in patients with otosclerosis who undergo stapes surgery, a small intraoperative tympanic membrane perforation can be safely and effectively managed with concurrent tympanoplasty. Following surgery, individuals in the study who had suffered perforation did not significantly differ from the other patients in terms of the air-bone gap or change in the air-bone gap. Moreover, the perforation group was not found to be at greater risk of postoperative reparative granuloma, otitis media, or sensorineural hearing loss, although these patients did report a greater rate of postsurgical dysgeusia than did the nonperforation group (30.0% vs 5.3%, respectively). ^[17]

Postoperative or persistent perforations may be managed by the usual means.

Infection is rare and must be identified and treated early to avoid profound sensorineural hearing loss, meningitis, and a prolonged hospital course.

Reparative granuloma formation in the middle ear (at the oval window) is a delayed complication appearing approximately 1-6 weeks postoperatively. This formation manifests as a gray mass behind the tympanic membrane with sudden hearing loss. Therapy consists of timely surgery to remove the granuloma, often with excellent results.

A floating footplate can develop if the footplate becomes dissociated from the annular ligament and, therefore, freely floats on the perilymph of the vestibule. In this case, the footplate or portions of it can sink into the vestibule. If a floating footplate develops, the surrounding promontory margin may be removed with the microdrill or laser to allow for a gap to place a right-angled micropick and remove the footplate. Great care must be taken not to allow the instrument or footplate to penetrate deeply into the vestibule, which can cause a profound sensorineural hearing loss.

Obliterative otosclerosis denotes a footplate completely obliterated by otosclerosis. This yields a greatly thickened and poorly defined footplate identifiable only with the use of landmarks such as the stapedial crura, round window, and facial nerve. This special situation requires a drill-out of the footplate, whereby a microdrill is used to blue-line the vestibule and the endosteum is removed with a micropick. Alternatively, a laser may be used to remove the bone, which may require many passes of the laser with intermittent pauses to remove bone char and to allow cooling.

A biscuit footplate refers to a localized focus of otosclerosis within the center of a footplate that has well-defined margins. Complete resection of the entire footplate or a formal stapedectomy can achieve complete removal of the otosclerosis in these patients.

Commonly quoted statistics indicate that 90% of appropriately chosen surgical candidates enjoy a significant hearing improvement. Eight percent experience no significant hearing improvement. Up to 2% (including 0.2% who may experience complete sensorineural hearing loss in the operative ear) experience additional hearing loss.

The aforementioned study by Wedel et al indicated that stapedotomy is an effective treatment for otosclerosis. The report looked at 93 stapedotomies in patients with otosclerosis, with the mean postoperative air-bone gap being 10 dB or less in 59% of surgeries. Other signs of success included improvement in 75% of procedures according to the Belfast rule of thumb. The investigators also determined that the size of the preoperative air-bone gap directly corresponded to how well the patient could hear after surgery. ^[16]

Revision stapes surgery yields less-successful results than primary surgery. Typically, the air-bone gap is closed to within 10 dB in approximately 50-70% of patients who undergo revision stapes surgery. Most surgeons prefer to use conscious sedation anesthetic technique when performing revision surgery. Manipulation of the existing prosthesis that elicits severe vertigo intraoperatively may indicate adherence of the prosthesis to the underlying vestibule. Further manipulation or removal of the prosthesis may cause a tear in the membrane and resulting profound sensorineural hearing loss. Having the patient awake enough to report vertigo during this portion of the operation is advantageous in this respect.

Residual or recurrent conductive hearing loss after stapes surgery has many causes. The most likely cause is a migration of the prosthesis out of the stapedotomy and subsequent fixation against the residual footplate or otic capsule margin. This is thought to be due to a contraction of collagen within a neomembrane created between the prosthesis and the membranous labyrinth, which lifts the prosthesis out of the oval window fenestration. This may cause complete or partial erosion of the incus due to vibration of the incus against a fixed prosthesis. Alternately, incus erosion may occur as a result of vascular compromise of the bone due to an overcrimped prosthesis. Other causes include malleus or incus fixation or incus dislocation.

A retrospective report by Shim et al indicated that in cochlear otosclerosis patients, the presence of cavitating lesions involving the internal auditory canal negatively impacts poststapedotomy audiologic results. This was reflected in the study patients’ mean air- and bone-conduction thresholds and air-bone gap values at 6-month follow-up, being 45.7 dB, 33.8 dB, and 11.8 dB, respectively, in patients with cavitating lesions, and 24.1 dB, 20.0 dB, and 4.1 dB, respectively, in those without. ^[18]

A study by Kishimoto et al indicated that postoperative outcomes in otosclerosis are influenced by the preoperative air-bone gap, the preoperative air conduction threshold, the presence of cochlear otosclerosis, male sex, laterality, and age. Eg, unilaterality and male sex predicted a better prognosis at 250 Hz, while cochlear otosclerosis predicted a worse prognosis at 2 kHz. The study involved 191 patients with otosclerosis (234 primary stapes operations). ^[19]

A prospective clinical study by Dziendziel et al of 168 otosclerosis patients with chronic tinnitus indicated that stapedotomy can reduce tinnitus severity. The investigators found that tinnitus had significantly improved in 93 patients (55%) postsurgery, with 62 patients (37%) reporting that the condition had disappeared completely. ^[20]

The following represent somewhat unresolved controversies. Exploration of each issue requires extensive discussion beyond the scope of this article.

• Preoperative tuning fork examination as a prognosticator for surgical success

• Laser stapedotomy minus prosthesis (STAMP) procedure in which the posterior footplate is detached from the diseased anterior footplate without disrupting ossicular chain continuity

• Implantable hearing devices (Baha) that may produce adequate gain for amplification without the risks of stapedectomy

• Endoscopic techniques now being applied to stapes surgery to further minimize morbidity ^[21]