Surgical Technique

Patient positioning and operating room setup are the same as described for primary stapes surgery. Early in our experience with revision stapes surgery, all cases were performed under local anesthesia to have constant patient feedback. However, the absence of intraoperative complications have led us to use general anesthesia or local anesthesia supplemented with intravenous sedation, depending on patient preference. The ear is prepared, draped, and injected as noted for primary surgery. Speculums of increasing size are inserted into the external canal to dilate and compress the skin of the ear canal, in order to improve exposure and reduce bleeding from the canal incision.

The ear canal incision is made parallel to the annulus at the end of the speculum. Elevation of the tympanomeatal flap with a Merocel microsponge reduces flap trauma and swelling. The elevated flap is everted into the anterior tympanomeatal sulcus to avoid obscuring the surgical field. If not previously removed, the posterior scutum is curetted to expose the oval window, pyramidal eminence and the inferior aspect of the facial nerve. Special care is taken to avoid removing excess scutal bone over the incus. Adhesions around the chorda tympani are removed and if necessary, the bone over the chorda tympani is outfrac-tured to allow displacement of the nerve inferior to the oval window. Mesenchymal adhesions are vaporized with the laser by holding the tip of the optical fiber directly on the tissue and using one or more pulses with a power setting 1 to 1.5 W and pulse duration of 0.1 s. A No. 3 suction in the nondominant hand is used to aspirate the laser plume. The adhesions are removed until the status of the malleus, incus, prosthesis, and oval window can be established.

In patients who have undergone a small fenestra procedure, the piston is usually displaced from the stapedotomy and bound down to adjacent bone with mesenchymal tissue. Adhesions around the piston may be removed with the laser at the lower power setting. After the connective tissue has been removed from the piston, the prosthesis is removed from the incus. This procedure is performed with a small right angle hook in the dominant hand, while the incus is steadied with the suction in the nondominant hand.

When a platinum ribbon/Teflon piston prosthesis has been used, the displaced prosthesis may also have been displaced from the incus and, not infrequently, may be found free in the mesotympanum. In this situation, it is important to examine the incus for necrosis. Soft tissue may obscure incus necrosis, and a fibrous union of the long process may be overlooked.

After the prosthesis has been removed from the middle ear, the stapes fenestra is inspected. The stapedotomy is usually filled with fibrous connective tissue that obscures the limits of the fenestra. The edges of the stapedotomy are defined with the laser at a power setting of 1 to 1.5 W and pulse duration of 0.1 second. After the circumference of fenestra has been established, the connective tissue filling the stapedotomy is thinned using the laser. Connective tissue is removed until the endos-teum is identified. The endostium is loosened from the edges of the stapedotomy with an oval window rasp. The distance from the incus to the fenestra is measured and the new prosthesis is cut approximately 0.3 mm longer. The new prosthesis, a Causse 0.6-mm (K.L.H.) or 0.4-mm (S.G.G.), is either placed through the endosteum and sealed with fibroadipose tissue (KLH) or the prosthesis is placed onto a vein graft used to seal the fenestra (S.G.G.).

In patients who have undergone total stapedectomy, the most common finding is a displaced prosthesis. If a wire/ Gelfoam or wire/tissue technique was used, the prosthesis is usually lateralized to the inferior edge of the oval window. Soft tissue in the oval window is removed around the shaft of the prosthesis until the knotted end has been exposed. In cases in which a wire/Gelfoam prosthesis was used, the tissue covering the knot is usually quite thin, and a power setting of 1 W with a pulse duration of 0.1 s is typically used. The cases with wire/tissue frequently have thick tissue surrounding and fixing the shaft and knot of the prosthesis. The power setting is increased to 1.5 W for removal of this thick tissue. The tissue is slowly vaporized around the circumference of the prosthesis until the knot is exposed. It is not uncommon to remove several millimeters of tissue until the knot of the prosthesis is encountered. After the prosthesis has been freed from the con nective tissue in the oval window, the prosthesis is removed from the incus as noted previously. The remaining connective tissue in the oval window is inspected. If the patient has undergone a wire/Gelfoam procedure, the oval window membrane is quite thin and the new prosthesis is placed on or through the membrane without further manipulation (K.L.H.). If connective tissue, such as fascia, vein, or fat, has been used to seal the oval window, the connective tissue remaining in the oval window after removal of the prosthesis may be several millimeters thick. This membrane is thinned in the posterior third of the oval window with the laser at a power setting of 1 to 1.5 W and pulse duration of 0.1 s. The membrane is thinned until the endosteum is identified and the fenestra in the connective tissue enlarged to a diameter of 0.6 mm (K.L.H.) or 0.8 mm (S.G.G.). The distance from the outer surface of the incus to the fenestra is measured and the prosthesis is cut 0.3 mm longer. A 0.6-mm Causse stapes prosthesis is placed on or through the endosteum and sealed with fibroadipose tissue (K.L.H.) or a 0.4-mm Causse prosthesis is placed over a vein graft to seal the fenestra (S.G.G.). The tympanomeatal flap is returned to the normal anatomic position and held in place with gelfoam and Merocel otowick expanded with saline solution.

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