Patients with otosclerosis may be managed by (1) observation, (2) pharmacologic therapy, (3) amplification, and (4) surgery or a combination thereof. The advantages and disadvantages of each should be discussed with the patient to guide informed consent.
Observation is the most inexpensive and least risky option. It is often the strategy preferred for patients with unilateral disease and those with a mild CHL. If the patient is not troubled by the degree of hearing loss, then no intervention is indicated and audiograms are usually obtained on yearly basis. The natural history of disease progression would predict further hearing loss over time and ultimately this might prompt intervention.
Therapeutic strategies to prevent the progression of otosclerosis have been directed toward the suppression of bone remodeling with fluorides and bisphosphonates. However, the efficacy of these agents has not been definitively proven and otologists vary widely in their recommendations regarding their use.
Fluoride reduces osteoclastic bone resorption and increases osteoblastic bone formation. Together, these actions may promote recalcification and reduce bone remodeling in actively expanding osteolytic lesions. Sodium fluoride is also thought to inhibit proteolytic enzymes that are cytotoxic to the cochlea and that may lead to SNHL.
Many otologists recommend the use of sodium fluoride in patients with new-onset otosclerosis, rapidly progressive disease, or inner ear symptoms such as SNHL and dizziness. The treatment is usually continued for 1–2 years. Patients with cochlear otosclerosis may be treated for longer periods of time or even indefinitely.
Bisphosphonates are potent antiresorptive agents that are useful for the prevention and treatment of osteoporosis and other conditions characterized by increased bone remodeling. They have been widely used in the treatment of osteoporosis and hold some promise in controlling otosclerosis. Following oral intake, bisphosphonates are incorporated into the bone, where they inhibit the osteoclastic activity. The most promising bisphosphonates in clinical use include alendronate, etidronate, risedronate, and zoledronate. These bisphosphonates potently inhibit bone resorption without significantly affecting bone deposition.
Most patients with otosclerosis have normal cochlear function with excellent speech discrimination and are therefore good hearing aid candidates. Before proceeding with surgery, patients should be encouraged to try a hearing aid (or aids). Some patients become successful hearing aid users and can therefore avoid surgery and its risks. However, although there is little risk to the patient with hearing aid use, there are some significant disadvantages when compared with the result of a successful surgery. The disadvantages include a poorer sound quality, cosmesis, cost, maintenance requirements, being able to hear only when the aid is in use, occlusion effect, and potential discomfort. In practice, most patients with good sensorineural reserve prefer to have surgery.
Patients with a severe to profound mixed hearing loss may require surgical correction of the conductive loss in order to gain benefit from a hearing aid. For patients who gain limited benefit from conventional hearing aids cochlear implantation is an effective alternative.
Most patients with CHL due to otosclerosis can be treated surgically (Table 51–3). The average patient with otosclerosis and a bone conduction level of 0–25 dB in the speech range (250–4000 Hz) and an air conduction level of 45–65 dB is a suitable candidate for surgery; an air-bone gap of at least 15 dB and speech discrimination scores of 60% or better are preferred. Clearly, those with a larger preoperative air-bone gap have more to gain from surgical intervention. If bilateral disease is present, generally the poorer hearing ear should be chosen. If the patient is a candidate for bilateral surgery, the poorer ear should undergo surgical correction first. It is recommended that the surgery on the contralateral ear be delayed at least 6 months to allow the patient to adjust to the first ear and assure stability of the hearing result.
Table 51–3. Contraindications to Surgery. |Favorite Table|Download (.pdf)
Table 51–3. Contraindications to Surgery.
Active otitis externa or otitis media.
Perforated tympanic membrane.
An only-hearing ear that does well with amplification.
Presence of vertigo and clinical evidence of labyrinthine hydrops.
Occupational considerations. Surgery may be inadvisable in individuals whose occupation or activities demand considerable physical strain or precise balance (eg, pilots, scuba divers, and construction workers).
Inner ear malformation.
Patients with unrealistic expectations.
A subset of patients with a severe-to-profound mixed hearing loss have been referred to as having far-advanced otosclerosis. In such cases, the otosclerotic process has progressed to the point where there is minimal to no detectable air conduction threshold and bone conduction is difficult to interpret at high levels because of vibrotactile sensations. Many such patients have been successfully treated with stapedotomy with postoperative amplification. Patients who do not gain sufficient benefit with amplification should be considered for cochlear implantation.
Surgery for otosclerosis is an elective procedure and should be preceded by a thorough explanation of all treatment alternatives. With refined techniques and new technologies, excellent outcomes (air-bone gap closure of less 10 dB) should be expected in over 90% of cases; however, the patient must be informed about the potential for short-term and long-term failure, the possible need for revision surgery and potential complications. In the long term, patients with otosclerosis lose inner ear function at a more rapid rate than the general population, and they are therefore more likely to eventually need a hearing aid even despite a successful surgery.
Surgery may be performed under local or general anesthesia depending on the preference of both the patient and the surgeon. There are several advantages to local anesthesia. (1) The patient's hearing can be tested after prosthesis placement by repositioning the tympanic membrane and either talking with the patient, performing tuning fork tests or even abbreviated intraoperative audiometry. (2) If the patient complains of vertigo during the procedure, the surgeon can alter his or her technique to reduce vestibular irritation. (3) The patient can avoid the postoperative nausea that often accompanies general anesthesia; the newly reconstructed ear is therefore not subjected to the potential extreme pressures associated with arousal from anesthesia. Despite these potential advantages the use of a general anesthetic is preferred by many surgeons. Patients operated under local anesthesia may experience pain, become anxious, and move unpredictably resulting in a more difficult and risky surgery.
Over the years there have been numerous advancements that have led to the currently employed surgical strategy. Many subtle variations of technique are used by surgeons but the basic concept and steps of the procedure are similar.
After adequate cleaning of the ear and administration of both a local anesthetic and a vasoconstrictive agent, a tympanomeatal flap is elevated to expose the middle ear space. If the stapes cannot be well visualized, the scutum is removed with a curet or drill. The ossicular chain is inspected and palpated to confirm the diagnosis of otosclerosis. Once the diagnosis is made, there is considerable variation in how a surgeon can handle the stapes superstructure and footplate. Typically, the incudostapedial joint is separated, the stapes superstructure removed and either a small fenestra stapedotomy or a total stapedectomy is performed, and the prosthesis is placed from the incus through the opening into the vestibule (Figure 51–5). The mobility of the prosthesis is assessed by gentle palpation of the malleus. Tissue or blood is used to seal the area around the prosthesis, and the tympanic membrane is repositioned. If surgery is performed under local anesthesia, intraoperative hearing improvement can be confirmed at this point by whispering in the patient's ear, the use of tuning forks or even abbreviated intraoperative audiometric testing. Most surgeons allow the patient to return home the day of the surgery.
(A) An intraoperative view is shown of a right middle ear after elevating and reflecting the tympanomeatal flap. Bone may need to be curetted or drilled away in order to offer the surgeon a view including the long process of the incus, the anterior and posterior crus of stapes, and the footplate. (B) After removal of the stapes suprastructure a small fenestra stapedotomy is made with a drill or laser and a prosthesis is connected to the long process of the malleus with the distal piston positioned just into the vestibule through the stapedotomy.
Lasers are commonly used in otosclerosis surgery. The cited advantages of laser use are an improved ability to prepare a bloodless fenestra, precise ablation of the footplate, and a reduced risk of footplate subluxation. Lasers are also used to generate heat to activate shape memory or self-crimping Nitinol prostheses. Various types of lasers have been safely used, including the CO2, KTP, and argon.
Patients with severe to profound hearing loss secondary to otosclerosis usually derive excellent benefit from cochlear implantation. However, implantation can be complicated by ossification or soft tissue fibrosis within the cochlea that may preclude a routine full electrode insertion. Preoperative imaging should alert to the surgeon to this possibility and the need for more advanced surgical maneuvers such as drilling the basal turn, placement in the scala vestibuli or other modification of the standard insertion technique.
After device activation there is a reported higher incidence of facial nerve stimulation from current spread through the otosclerotic bone. Reprogramming the device and eliminating the offending channels can usually eliminate this undesirable side effect. In a more recent study, increased speech perception outcomes were associated with less severe signs of otosclerosis on CT scan, full insertion of the electrode, little or no facial nerve stimulation, and a limited need for channel inactivation.
Most patients should be encouraged to try a hearing aid before a revision because of the increased risk of SNHL with the second procedure. Only experienced stapes surgeons should perform revision surgery. The reasons for failure of the initial surgery can include incus necrosis, displacement of the prosthesis from the incus or oval window, insufficient stapedotomy size, and reobliteration of the oval window. It is also important to consider the possibility of previously unrecognized diagnosis such as malleus or incus fixation or superior semicircular canal dehiscence syndrome. Because the risk of hearing loss is higher in revision surgery, it is advisable to approach the surgery with an idea of exploring the ear and proceeding with the revision surgery only if it appears favorable.
Patients with SNHL are less likely to benefit from revision surgery. In a large series, up to 80% of patients with postoperative SNHL had no identifiable cause on revision exploration. It is now recommended that for those with postoperative SNHL, only patients with a history of trauma or dizziness be considered for revision. Such circumstances might be caused by a persistent perilymphatic fistula and be amenable to surgical correction.
Stapes Surgery in Children
With the increased risk of congenital malformations and the low overall incidence of pediatric disease, CT is always recommended on younger patients suspected of having otosclerosis. Owing to the rarity of juvenile otosclerosis, the effectiveness of stapedectomy surgery in children has been less critically reviewed. Pediatric patients are more likely to require the use of a drill (“drill-out stapedotomy”) for obliterative otosclerosis as compared to their adult counterparts. Despite this finding, reports have disclosed up to a 91.7% success rate in achieving a 10 dB air-bone gap after five or more years of follow-up. Other studies reported an 82% success rate in primary otosclerosis cases but only a 44% success rate in cases of congenital footplate fixation.
The optimal time for surgery in children remains a point of controversy. With the higher incidence of otitis media during childhood, there is concern for the potential spread of infection through the oval window resulting in meningitis. Moreover, most children benefit from amplification, and delaying surgery until they are older is an acceptable option.
Derks W, de Groot JA, Raymakers JA, Veldman JE. Fluoride therapy for cochlear otosclerosis? An audiometric and computerized tomography evaluation. Acta Otolaryngol
(Discusses fluoride therapy rest at the progression of sensorineural hearing loss in low and high frequencies.)
Lesinski SG, Palmer A. Lasers for otosclerosis: CO2 versus argon and KTP-532. Laryngoscope
(The optical properties of the CO2
laser are preferable to those of the argon and KTP-532 lasers.)
Rotteveel LJ, Snik AF, Cooper H, Mawman DJ, van Olphen AF, Mylanus EA. Speech Perception after Cochlear Implantation in 53 Patients with Otosclerosis: Multicentre Results. Audiol Neurootol
(Patients with otosclerosis receive excellent hearing rehabilitation with cochear implantation).