Pearls on otosclerosis and stapedectomy.

Physical examination

* The results of your audiometry must be confirmed by a tuning fork test. In most cases, only a 512-Hz tuning fork is necessary. The Weber test is more sensitive than the Rinne test. Be sure to mask the better-hearing ear with narrow-band noise when there is a substantial difference between the two ears. Be aware that cartilaginous collapse, caused by the earphone, may yield a false-positive result for a conductive hearing loss.

* You should be able to very closely predict the audiometric results by using your own voice. If the patient hears the softest whisper (when your lips are moving), the hearing loss is less than 15 dB. Other benchmarks: a soft whisper, less than 20 dB; a soft to medium whisper, 30 to 40 dB; a moderate whisper, 50 dB; a loud whisper, 60 dB; a soft voice, 70 dB; a medium voice, 80 dB; and a shout, 90 dB. Patients with high-frequency hearing losses will still hear a soft whisper. Mask with white noise when there is a substantial difference in hearing between the two ears.

* Test the movement of the malleus with your pneumatic otoscope or with direct palpation under the microscope after anesthetizing the umbo with phenol.

* If the hearing is nearly equal in the two ears and the decision is to either (1) perform revision surgery on the previously operated ear or (2) operate on the previously unoperated ear, choose the second option. Success rates in previously unoperated ears are well above 90%, while those for revision surgery are approximately 75%.

* In planning to operate on both ears in which the hearing is nearly equal, do the left ear first if you are right-handed; conversely, do the right ear first if you are left-handed. This is especially important for obese patients, for patients with a large chest or short neck, and for patients who cannot freely turn their necks.

* In patients with both otosclerosis and serous otitis media, treat the serous otitis media first.

* Postpone surgery in patients with external otitis until the otitis is adequately treated.

* Postpone surgery if the patient has any infection anywhere.

* Do not perform surgery if the air-bone gap is less than 20 dB.

* Always test each patient at least twice before surgery.

* Do not depend on the Schwartz sign. It is rarely seen.

* Make sure that the hearing aid is kept out of the ear to be operated on for at least a week before surgery.

* If the eardrum is atrophic, be prepared to repair it at the time of surgery by reinforcing the drum with fascia, perichondrium, or a vein graft.

* If there is attic retraction, be prepared to repair it with cartilage or perichondrium.

* If a perforation is present and it is anything but very small, perform a tympanoplasty. Schedule the stapedectomy for 4 to 6 months later.

* If exostosis is present but not extremely advanced, remove it at the time of stapedectomy.

* If a patient has a tiny canal, have your audiologist make a series of molds that will gradually enlarge the canal over a period of 6 months to a year prior to surgery.

* If the patient has advanced tympanosderosis or a history of frequent ventilation tubes, suspect chronic ear disease.

Decision making

* You can perform a stapedectomy on children with bilateral otosclerosis. We have operated on patients as young as 6 years. In children with unilateral otosclerosis, we prefer to wait until the child is responsible enough to avoid situations that would endanger the success of the stapedectomy. (1)

* You will find more cases of obliterated otosclerosis in children than in adults (27 and 6%, respectively). Disease in children is very often more rapidly progressive, and your results will not be quite as good as those in adults. Nevertheless, the results are still gratifying. Closure rates are 92% in children and 97.5% in adults. Ten years postoperatively, the average child would have lost 7 dB of hearing (0.7 dB/yr). (1)

* Stapedectomy in the elderly (70 to 92 yr) yields the same good results as are seen in younger patients. Older patients will not have any more unsteadiness than do younger patients. (2)

* For patients with far advanced otosclerosis, you may perform a stapedectomy even if the speech discrimination score is 0. But if the results in one ear are not good, do not operate on the other ear. (3)

* Airplane pilots can undergo stapedectomy if a piston and a tissue graft are used. We have published a report on the results of stapedectomy in 9 fighter pilots. (4) All received a piston prosthesis and a tissue graft. Three months after surgery, they were put through a decompression chamber, and none of them experienced any vestibular or otologic symptoms. Three years postoperatively, they had accumulated 4,160 hours of combat or simulated combat flying time and experienced no inner ear problems. The armed forces now allow their pilots to return to flight status if our protocol is followed. (4) The same is true for the airlines.

* Do not hesitate to make the diagnosis of cochlear otosclerosis. It is easy. Patients present with a moderate, usually flat sensorineural hearing loss, excellent speech discrimination, an absence of cochlear reflexes, and very often a family history. As for treating cochlear otosclerosis, you have a choice. You can tell your patient, "You have a nerve loss and there is nothing I can do for you." Or you can say, "You probably have cochlear otosclerosis, which is a type of nerve loss. I am going to place you on sodium fluoride. It will not improve your hearing, but in many cases it will prevent further loss of the hearing nerve itself."

* Do not fail to make the diagnosis of cochlear otosclerosis if, for example, you have operated on a parent and 3 siblings of a 40-year-old woman who presents with a 40-dB hearing loss with good speech discrimination and absent reflexes. We often put patients like this on sodium fluoride, even if the reflexes are present.

* If a patient has a conductive hearing loss and reflexes are present, obtain computed tomography of the temporal bones to rule out superior semicircular canal dehiscence.

* Do not perform a stapedectomy on a patient whose reflexes are present.

* As soon as a diagnosis of otosclerosis is made, all adults should be treated with Florical (a sodium fluoride and calcium supplement), 2 to 4 tablets per day depending on the amount of nerve loss and the size of the patient, plus 400 U of vitamin D. Treatment can continue indefinitely after surgery; the greater the nerve involvement is, the longer the treatment should be. Adults who are taking a tetracycline or who have kidney stones can take Florical. Those who experience gastric symptoms on Florical may switch to Monocal, a form of sodium fluoride and calcium that is absorbed in the intestine rather than the stomach. Adolescents can be treated with 2.2 mg/day of sodium fluoride.

* If the sensorineural component of the hearing loss continues to worsen in postoperative patients on Florical and vitamin D, add 600 mg of Caltrate (concentrated calcium) and 30 mg of risedronate twice a week.

* When appropriate, always offer a patient with a moderate hearing loss a hearing aid trial in lieu of surgery.

* Patients with van der Hoeve syndrome should not be denied stapedectomy. They will do almost as well as patients who do not have osteogenesis imperfecta.

* Do not operate on a patient whose first language is English and whose hearing loss is 70 dB or less unless their speech discrimination score is 80% or better.

* If a patient has or had a dehiscent overhanging facial nerve in one ear, there is a 25% chance that he or she will have one in the other ear.

* If an obliterated footplate is found in one ear, there is a 40% chance that it will be found in the other. (5)

References

(1.) Lippy WH, Burkey JM, Schuring AG, Rizer FM. Short- and long-term results of stapedectomy in children. Laryngoscope 1998;108(4 Pt 1):569-72.

(2.) Lippy WH, Burkey JM, Fucci MJ, et al. Stapedectomy in the elderly. Am J Otol 1996;17(6):831-4.

(3.) Lippy WH, Battista RA, Schuring AG, Rizer FM. Far-advanced otosclerosis. Am J Otol 1994;15(2):225-8.

(4.) Katzav J, Lippy WH, Shamiss A, Davidson BZ. Stapedectomy in combat pilots. Am J Otol 1996;17(6):847-9.

(5.) Daniels RL, Krieger LW, Lippy WH. The other ear: Findings and results in 1,800 bilateral stapedectomies. Otol Neurotol 2001;22(5):603-7.

From The Lippy Group for Ear, Nose and Throat, Warren, Ohio.