Stapedectomy

A stapedectomy is a surgical procedure of the middle ear performed to improve hearing. The world's first stapedectomy is credited to Dr. John J. Shea, Jr., performed in May, 1956, the first patient being a 54 year-old housewife who could no longer hear even with a hearing aid.

STAPEDECTOMY (Left ear, surgeon's view) The replacement of the stapes with a prosthesis is sometimes called stapedioplasty. In this photogtaph, a titanium bucket prosthesis is used to replace the stapes.

STAPEDECTOMY (Right ear, surgeon's view)Like the previous photograph, this one again shows the titanium bucket prosthesis in place. The chorda tympani was retracted anteriorly and is visible at the posterior edge of the tympanomeatal flap.

STAPEDECTOMY (Right ear, surgeon's view) This photograph shows the light reflex in the round window. After placing the prosthesis, the reconstructed ossicular chain assembly is tested by moving the malleus with an instrument. If the round window light reflex moves, it indicates that the movement is transmitted from the malleus to the inner ear fluids.

If the stapes footplate is fixed in position, rather than being normally mobile, then a conductive hearing loss results. There are two major causes of stapes fixation. The first is a disease process of abnormal mineralization of the temporal bone called otosclerosis. The second is a congenital malformation of the stapes.

In both of these situations, it is possible to improve hearing by removing the stapes bone and replacing it with a micro prosthesis - a stapedectomy, or creating a small hole in the fixed stapes footplace and inserting a tiny, piston-like prothesis - a stapedotomy.

In a normal ear (see left) , drum vibrations move the malleus (hammer) which is connected to the incus (anvil). The stapes (stirrup) transmits sound vibration from the incus to the inner ear fluids. Otosclerosis (see middle) is a deposit of new bone ( depicted in white) that prevents the footplate of the stapes from moving, thus causing hearing loss. In a stapedectomy (see right), the stapes is removed and a prosthesis is placed to transmit sound vibration from the the incus (anvil), to a fat plug (fascia or vein) in the oval window of the inner ear.

The results of this surgery are generally most reliable in patients whose stapes has lost mobility because of otosclerosis. Nine out of ten patients who undergo the procedure will come out with significantly improved hearing while less than 1% will experience worsened hearing ability or deafness. Successful surgery usually provides an increase in hearing ability of about 20 dB. That is as much difference as having your hands over both ears, or not. The relative success rate for this surgery varies considerably between surgeons. As for any surgical procedure, all other variables fixed, the more experience the surgeon has with the surgery, the better the outcome. Since stapes surgery is fairly rare, significantly better success rates are found at facilities that specialize in this procedure.

Indications

Indications of stapedectomy:

1. Conductive deafness due to fixation of stapes.
2. Air bone gap of at least 40 dB.
3. Presence of Carhart's notch in the audiogram of a patient with conductive deafness.
4. Good cochlear reserve as assessed by the presence of good speech discrimination.

Contraindications

Contraindications for stapedectomy:

• Poor general condition of the patient.
• Only hearing ear.
• Poor cochlear reserve as shown by poor speech discrimination scores
• Patient with tinnitus and vertigo
• Presence of active otosclerotic foci (otospongiosis) as evidenced by a positive flemmingo sign.
• Conductive deafness due to Ehlers-Danlos Syndrome (EDS)

Complications

Complications of stapedectomy:

• Facial palsy
• Vertigo in the immediate post op period
• Vomiting
• Perilymph gush
• Floating foot plate
• Tympanic membrane tear
• Dead labyrinth
• Perilymph fistula
• Labyrinthitis

When a stapedectomy is done in a middle ear with a congenitally fixed footplate, the results may be excellent but the risk of hearing damage is greater than when the stapes bone is removed and replaced (for otosclerosis). This is primarily due to the risk of additional anomalies being present in the congenitally abnormal ear. If high pressure within the fluid compartment that lies just below the stapes footplate exists, then a perilymphatic gusher may occur when the stapes is removed. Even without immediate complications during surgery, there is always concern of a perilymph fistula forming postoperatively.

Stapedotomy

A modified stapes operation, called a stapedotomy, is thought by many otologic surgeons to be safer and reduce the chances of postoperative complications. In stapedotomy, instead of removing the whole stapes footplace, a tiny hole is made in the footplate - either with a microdrill or with a laser, and a prosthesis is placed to touch this area with movement of the tympanic membrane. This procedure greatly reduces the chance of a perilymph fistula (leakage of cochlear fluid) and can be further improved by the use of a tissue graft seal of the fenestra.

External links

• Balasubramanian T (2006). "Stapedectomy". Retrieved 2007-07-03. - details of the procedure with pictures
• Amanda Jenner, Lynne Shields PhD ccc-slp "Speech and Language Issues" [1]
• M. Hawthorne, FRCS-ENT Surgeon. "Hearing Impairment and EDS" [2]

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