Stapedectomy

Definition

Stapedectomy is a surgical procedure in which the innermost bone (stapes (pronounced “stay-peas”)) of the three middle ear bones is surgically removed and replaced with a synthetic ear bone (prosthesis). The prosthesis is typically made of titanium, plastic or stainless steel. The operation was first performed in 1956.

Indications

A stapedectomy is performed to improve sound conduction into the inner ear. Otosclerosis is the most common ear condition that is treated by stapedectomy. Otosclerosis is a condition in which new bone grows around the bottom of the stapes bone in an area of the stapes known as the footplate . Hardening of bone in this area prevents the stapes from moving, thus, sound cannot enter the inner properly. For further information regarding otosclerosis, please click here. Other conditions that may cause a stiffening of the stapes bone include: tympanosclerosis, osteogenesis imperfecta and Paget’s disease.

Demographics

Otosclerosis affects about 10% of the United States population. It is an autosomal dominant disorder with variable penetrance. These terms mean that a child having one parent with otosclerosis has a 50% chance of inheriting the gene for the disorder, but that not everyone who has the gene will develop otosclerosis. Otosclerosis develops most frequently in people between the ages of 10 and 30. In most cases, both ears are affected; however, about 10–15% of patients diagnosed with otosclerosis have loss of hearing in only one ear. The disorder affects women more frequently than men by a ratio of 2:1. With regard to race, Caucasian and Asian Americans are more likely to develop otosclerosis than African Americans.

Description

A stapedectomy is an outpatient surgical procedure (patients go home the day of surgery) that typically requires approximately one hour to perform. General anesthesia or local anesthesia with intravenous sedation (twilight anesthesia) is given. The surgery is performed through the ear canal while the surgeon uses a high power operating microscope. The only outward incisions are on the arm for a vein graft, the back of the ear lobe for a fat graft or behind the ear for a fascia graft. These graft materials are used to seal the inner ear fluids, as discussed in more detail below.

Details of Stapedectomy

With the patient under local or general anesthesia, the surgeon lifts the ear canal skin near the eardrum and folds up the eardrum with attached ear canal skin (much like rolling up a window shade). Using an operating microscope, the surgeon is able to see the middle ear structures in detail. The bones of hearing (ossicles: malleus (1st), incus (2nd), stapes (3rd)) are evaluated to confirm the diagnosis of otosclerosis.

Next, the surgeon separates the stapes from the incus; freed from the stapes, the incus and malleus bones can move easily. A laser is used to cut through the tendon and arch of the stapes bone. The top portion of the stapes is removed.

At this point in the operation, the surgeon may perform a stapedotomy or a stapedectomy, depending on the preference of the surgeon. A stapedotomy involves creating a hole in the bottom portion of the stapes (footplate) that joins the middle ear to the inner ear. Most surgeons use a laser to create the hole in the footplate. The laser is used to minimize trauma to the inner ear underneath the footplate. A stapedotomy hole is only slightly larger than the diameter of the prosthesis (typically 0.8 mm or less) used for stapes reconstruction. After the footplate is opened, one end of a stapes prosthesis is placed in the inner fluid (perilymph) exposed by opening the footplate. The other end of the prosthesis is attached to the incus. The tissue graft or blood is used to create a seal around the prosthesis near the inner ear. The graft prevents inner ear fluid from leaking into the middle ear, which could cause hearing loss and/or dizziness.

A stapedectomy involves removing a larger portion of the footplate, typically one-third to one-half of the footplate. A laser is also used in stapedectomy. After opening the footplate, a graft is placed directly over the exposed inner ear. One end of the stapes prosthesis is placed over the graft and the other end is attached to the incus. Overall, the results of stapedotomy versus stapedectomy are very similar.

After the prosthesis is placed, the eardrum is then gently replaced into its normal position and held there by absorbable packing ointment or a gelatin sponge.

Stapedectomy or stapedotomy will improve hearing in approximately 95% of cases.