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Revision stapedectomy
REVISION STAPEDECTOMY JOHN W. HOUSE, MD
The stapedectomy procedure has been in use since first introduced by John Shea, Jr. in 1956. Even though the results for primary surgery are quite good, the results for revision surgery do not carry as high a success rate. In addition, complications are more frequent for revision surgery. Otosclerosis is a common cause of progressive conductive hearing loss in young adults, which is more frequent in females than males and may be accelerated by pregnancy. The stapedectomy procedure has evolved from a total stapedectomy to a partial stapedectomy to a small fenestra stapedotomy. Various prostheses have been used over the years with uniformly high rates of success. The most common causes of failure in stapedectomy are displacement of the prosthesis from the oval window and erosion of the incus. Other reasons for failure are fixation of the malleus and incus, fistula or, rarel~ displacement of the prosthesis into the vestibule. Before attempting revision surgery, the risks, complications, and alternatives must be thoroughly discussed with the patient. Many authors have described the use of the laser when performing the revision surgery. This seems to have reduced the complications, which were formally observed with revision surgery.
A discussion of revision surgery for otosclerosis must include the evaluation, indications, and technique of the primary procedure as well as for revision stapedectomy. For this reason, there will be a brief discussion of the evaluation of new patients and the stapedectomy technique that the author uses on most of the stapedectomies. The selection process for both primary and revision surgery is a very important aspect of the treatment of patients with otosclerosis. Important components of this selection process are the histor~ physical examination, audiometric studies and the counseling of the patient regarding the risks, complications, and alternatives to surgical treatment.
SELECTION OF PATIENTS AND PREOPERATIVE EVALUATION Compared with primary surgery there are additional factors that must be considered when evaluating a patient for surgery. These factors include: The initial result. Was there an immediate improvement or no change in hearing? Was the subsequent decrease in hearing gradual or rapid? Are there any associated events, such as barotrauma, infection, or associated vertigo? Was there associated vertigo with the procedure or subsequently? Were you the primary surgeon or was the procedure performed elsewhere? The type of procedure (total or small fenestra); type of oval window seal and length and type of prosthesis. The condition of contralateral ear. From the House Ear Clinic & House Ear Institute, Los Angeles, CA. Address reprint requests to John W. House, MD, Clinical Studies Department, House Ear Institute, 2100 W Third St, 5th Floor, Los Angeles, CA 90057-9927. Copyright © 1998 by W.B. Saunders Company 1043-1810/98/0902-0001 $08.00/0 68
The operative report (if available).
HISTORY The typical history of the patient with otosclerosis is that of a progressive hearing loss which begins in the late teens or 20s. Some patients may not notice the loss until they are even olden Recently, Mutawakel F. Hajjaj, MD (Research Scholar at House Ear Institute) and the author reviewed the charts of 543 of stapedectomy patients and found that two-thirds were female, and that bilateral stapes fixation occurred in 70%. A positive family history was present in about 50% of these otosclerotic patients. These findings are similar to those reported in the literature. Other important aspects of the history are whether the patient had any vertigo, a prior history of infections, or any fluctuation of hearing. Age is not a factor when considering surgery. We have operated on patients with otosclerosis as young as 6 years old 1 and as old as 90. When considering an older patient for surger~ other factors are important. These include the patient's general health, the status of the cochlear reserve, and possibly the family's history of longevity. Certainly, hearing aids can be advised in all cases of otosclerosis, and the patient should be given this option.
EXAMINATION The examination of all patients includes otoscopic inspection of the ear canal, tympanic membrane, and tuning fork evaluation. The external auditory canal is inspected for any signs of infection or bony growths (exostosis or osteomas). The size of the canal may be a consideration, but in the author's experience, it never has been necessary to perform the surgery through a postauricular or endaural approach. In cases in which the patient has large osteomas or exostosis, these were removed through a postauricular approach, and the stapedectomy was performed at the
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 9, NO 2 (JUN), 1998: PP 68-71
same time. The mobility of the tympanic membrane is checked with pneumotoscopy to rule out serous effusion as a cause of the conductive hearing loss. Occasionally a reddish blush can be observed in the area of the anterior oval window. This is called a Schwartze sign and is due to the increased vascular supply to the active otospongiotic focus near the oval window. If there are any questions of the standard otoscopy, the ear is examined using the operating microscope in the office. In the case of revision surgery, there may be more problems with the tympanic membrane. Care is taken to inspect the posterior superior quadrant for possible retraction or perforation. Occasionally, the prosthesis can be observed on the undersurface or protruding through the tympanic membrane. Tuning forks are an important aspect of our evaluation and are performed on all patients. The Weber test will lateralize to the ear with the greater conductive hearing loss. With the 512 Hz tuning fork, bone conduction is greater than air conduction when the air bone gap is >15 to 20 dB. Bone conduction is greater than air conduction with the 1,024 Hz tuning fork when the air bone gap is more than 25 to 30 dB. We will not perform a stapedectomy on a patient if they do not reverse at least the 512 Hz tuning fork regardless of the results of the audiogram.
AUDIOMETRY All patients undergo an audiometric evaluation, induding air conduction, bone conduction and speech audiometry, performed by an audiologist. It is important in unilateral cases to use the appropriate masking. Typically, the patient with otosclerosis has good bone conduction with a significant air-bone gap. Speech discrimination is good and the speech reception threshold roughly matches the four frequency (500, 1,000, 2,000 and 3,000 Hz) speech average. Generally a minimum air-bone gap would be at least 20 dB. However, as previously stated, we rely greatly on our tuning fork test results. Therefore, at times we perform surgery if the patient reverses the forks, but the audiogram shows a minimal air-bone gap. In these cases we find postoperatively, there is an improvement in the bone conduction when compared with the preoperative bone conduction. Generally we do not perform tympanometry as part of our preoperative evaluation. The shape of the tympanogram is nondiagnostic, and the classic findings are a normal tympanogram and static compliance accompanied by absent ipsilateral and contralateral acoustic reflexes.
INDICATIONS FOR REVISION SURGERY The usual reason for revision stapedectomy is a significant conductive hearing loss. Occasionally, there are other indications for revision surgery. VERTIGO With small fenestra stapedectomies, vertigo is rare. Generally, we do not perform revision surgery on patients who have immediate postoperative vertigo. In cases of delayed vertigo, revision may be indicated to rule out and possibly repair a perilymph fistula (rare). Some patients complain of brief vertigo when they burp, Valsalva, or push on the ear. This can be an indication of a long prosthesis. JOHN W. HOUSE
DISTORTION On rare occasions some patients report distortion in hearing with some sounds. I have found that at revision surgery the wire is loose on the incus and tightening it relieves this annoying symptom.
SURGERY Before any surgery the patient in counseled about the risks, complications, and alternatives. If the surgery is being performed for a hearing loss, the patient is informed about hearing aids as an alternative to surgery. If there is any question regarding surge13~ the patient is advised to have a trial of hearing aids before the surgery is performed. The risks and expected results are different for revision surgery when compared with primary stapedectomy. We expect at least a 90% chance of significant gain in hearing to within 10 dB of the bone conduction. With revision surger~ the chance of this gain in hearing is only about 80%. In addition, the chance of further hearing loss is greater. We normally tell our stapedectomy patients that there is less than a 2% chance of further hearing loss and less than 1% chance of total hearing loss. With revision surgery, the patient is told that the chances of these poor results are somewhat higher. In all revision surgeries, the author keeps the KTP laser available, and a small area above the ear is shaved in case temporalis fascia is needed. It is imperative to have various prostheses available. These include all lengths of pistons and total ossicular prostheses (TOPs/TORPs). Along with having the laser available a microdrill is on hand in case the footplate needs to be drilled. ANTICIPATED FINDINGS In my experience, the most common finding at revision surgery is a laterally displaced prosthesis that has come off of the incus and out of the oval window fenestra. In these cases the prosthesis is changed, the fenestration reopened, and the prosthesis replaced. The next most common cause is an eroded long process of the incus that will no longer support a prosthesis. In these cases, the incus and stapes footplate are removed and a TOP over perichondrium is used for the reconstruction. A less common finding is a solid footplate. It may be that the first surgeon had a floating footplate and placed the prosthesis from the incus to the footplate. It subsequently refixed. A hint at what we might find is to ask if the patient had an initial improvement in hearing or not. If not, it may be that the stapes footplate was not removed. In the author's experience, there have been many interesting findings. Recently, there was a case in which there was a stapes prosthesis attached to the incus and extending into the area of the footplate. The stapes superstructure was still in place and firmly fixed. In this situation, the prosthesis was removed, a fenestra performed, the prosthesis placed, and the stapes superstructure removed. In other cases, the stapes footplate was intact and fixed despite several previous procedures.
SURGICAL TECHNIQUE The following is a brief description of the author's routine stapedectomy technique. The surgery is performed under local anesthesia with preoperative sedation. A standard tympanomeatal incision is performed and the middle ear 69
FIGURE 3. The piston is placed from the incus to the fenestra before removal of the superstructure.
FIGURE 1. The currette is used to remove posterior superior bony canal wat to obtain better visualization of the stapes.
entered. Usually the posterior superior canal wall is curetted for exposure of the oval window (Fig 1). Adequate exposure is achieved when the facial nerve and pyramidal process are visualized. The malleus, incus, and stapes are
palpated. The distance from the incus to the footplate is measured. With the stapes superstructure in place, a 0.7-mm diamond is used to create a fenestra in the center of footplate (Fig 2). At times, the part of the posterior crura is partially or totally removed with the drill. With the stapes in place, a 0.6-mm Teflon platinum prosthesis is placed from the incus to the fenestra and crimped onto the incus (Fig 3). The incudal stapedial joint is cut, the stapedial tendon is cut, the stapes superstructure fractured inferiorly and removed.
i
FIGURE 2. The microdrill and 0.7-mm diamond burr create a fenestra in the center of the stapes footplate. The fenestra is created before removing the stapes superstructure. 70
REVISION STAPEDECTOMY
Almost all of our revision surgery is performed using local anesthesia. This is especially important with revision surgery, because we want to know if the patient experiences any vertigo during the manipulation of the prosthesis or tissue in the oval window. If the patient reports vertigo, this may indicate adhesions extending into the vestibule to the saccule. Pulling out the soft tissue or prosthesis could result in a sensorineural hearing loss or vertigo. The standard tympanomeatal flap is elevated and the middle ear entered. Typically, the chorda tympani nerve is adherent to the undersurface of the tympanic membrane and therefore must be cut. We have found that sectioning the nerve causes less taste disturbance than when the nerve is stretched. Frequently, there are adhesions in the middle ear. These can be sectioned with middle ear scissors or the laser. The incus is identified and the previous prosthesis searched for. When the prosthesis is seen, it must be determined if it is still attached to the incus, and if it is in the oval window or vestibule. In my experience, the most common cause of failure is the prosthesis coming off of the incus with or without incus necrosis. In these cases, the distal end of the prosthesis is usually out of the fenestra. The prosthesis is carefully removed and the oval window carefully inspected. When tissue covers the footptate or oval window, it must be removed to determine if the footplate is intact, absent, or if there is a fenestra present. Generally, this tissue is best removed using a laser. If the membrane can be identified and is thin, it is not necessary to remove it. The author will make a small opening in it to enter the vestibule. A piston is placed from the incus to this newly created fenestra. If the footplate is found to be intact and fixed, a standard 0.7-mm fenestra is performed with the diamond drill and a 0.6-mm prosthesis placed. When the incus is necrotic and short, one of two techniques is used. In both techniques, the entire footplate is removed and the oval window covered with perichondrium. At times, a total ossicular prosthesis is placed from the tympanic membrane with interposition cartilage to the
JOHN W. HOUSE
oval window. In these cases, the remaining incus is removed. On other occasions, the author uses a prosthesis which has an off set and can be placed from the remaining Incus to the oval window. On several occasions, the author has found the prosthesis has slipped off of the incus and entered the vestibule. When a wire loop has been used for the primary surgery, it is best to leave it in the vestibule and possibly reconstruct with fascia over the oval window and a piston prosthesis. When a Teflon piston had been used, it is safe to carefully remove it, because membranous structures will not adhere to this type of prosthesis, This is also true with the polyethylene struts that were used in the early 1960s. They were abandoned because they tended to slip into the vestibule causing nerve loss or vertigo. The key to revision surgery is having available all the necessary prosthesis and tools, such as the laser, to be able to correct any condition that one might encounter.
SUMMARY In summar~ revision stapes surgery can be safely performed. The key factors are a careful history, physical examination (including tuning forks), and audiometry. The surgery is best performed under local anesthesia and the patient instructed to inform the surgeon if h e / s h e experiences any dizziness or vertigo. A laser is helpful in removing scar tissue from the oval window. It is important to assess the status of the oval wIndow and footplate, if present. The middle ear sound conducting mechanism is reconstructed according to the findings at revision surgery. Even though the results with revision surgery are not as good as primary surger~ the outcome does make doing revision surgery worthwhile.
REFERENCE 1. House JW,ShellyJL,Antennas JC: Stapedectornyin children. Laryngoscope90:1804-1809,1980
71
The stapedectomy procedure has been in use since first introduced by John Shea, Jr. in 1956. Even though the results for primary surgery are quite good, the results for revision surgery do not carry as high a success rate. In addition, complications are more frequent for revision surgery. Otosclerosis is a common cause of progressive conductive hearing loss in young adults, which is more frequent in females than males and may be accelerated by pregnancy. The stapedectomy procedure has evolved from a total stapedectomy to a partial stapedectomy to a small fenestra stapedotomy. Various prostheses have been used over the years with uniformly high rates of success. The most common causes of failure in stapedectomy are displacement of the prosthesis from the oval window and erosion of the incus. Other reasons for failure are fixation of the malleus and incus, fistula or, rarel~ displacement of the prosthesis into the vestibule. Before attempting revision surgery, the risks, complications, and alternatives must be thoroughly discussed with the patient. Many authors have described the use of the laser when performing the revision surgery. This seems to have reduced the complications, which were formally observed with revision surgery.
A discussion of revision surgery for otosclerosis must include the evaluation, indications, and technique of the primary procedure as well as for revision stapedectomy. For this reason, there will be a brief discussion of the evaluation of new patients and the stapedectomy technique that the author uses on most of the stapedectomies. The selection process for both primary and revision surgery is a very important aspect of the treatment of patients with otosclerosis. Important components of this selection process are the histor~ physical examination, audiometric studies and the counseling of the patient regarding the risks, complications, and alternatives to surgical treatment.
SELECTION OF PATIENTS AND PREOPERATIVE EVALUATION Compared with primary surgery there are additional factors that must be considered when evaluating a patient for surgery. These factors include: The initial result. Was there an immediate improvement or no change in hearing? Was the subsequent decrease in hearing gradual or rapid? Are there any associated events, such as barotrauma, infection, or associated vertigo? Was there associated vertigo with the procedure or subsequently? Were you the primary surgeon or was the procedure performed elsewhere? The type of procedure (total or small fenestra); type of oval window seal and length and type of prosthesis. The condition of contralateral ear. From the House Ear Clinic & House Ear Institute, Los Angeles, CA. Address reprint requests to John W. House, MD, Clinical Studies Department, House Ear Institute, 2100 W Third St, 5th Floor, Los Angeles, CA 90057-9927. Copyright © 1998 by W.B. Saunders Company 1043-1810/98/0902-0001 $08.00/0 68
The operative report (if available).
HISTORY The typical history of the patient with otosclerosis is that of a progressive hearing loss which begins in the late teens or 20s. Some patients may not notice the loss until they are even olden Recently, Mutawakel F. Hajjaj, MD (Research Scholar at House Ear Institute) and the author reviewed the charts of 543 of stapedectomy patients and found that two-thirds were female, and that bilateral stapes fixation occurred in 70%. A positive family history was present in about 50% of these otosclerotic patients. These findings are similar to those reported in the literature. Other important aspects of the history are whether the patient had any vertigo, a prior history of infections, or any fluctuation of hearing. Age is not a factor when considering surgery. We have operated on patients with otosclerosis as young as 6 years old 1 and as old as 90. When considering an older patient for surger~ other factors are important. These include the patient's general health, the status of the cochlear reserve, and possibly the family's history of longevity. Certainly, hearing aids can be advised in all cases of otosclerosis, and the patient should be given this option.
EXAMINATION The examination of all patients includes otoscopic inspection of the ear canal, tympanic membrane, and tuning fork evaluation. The external auditory canal is inspected for any signs of infection or bony growths (exostosis or osteomas). The size of the canal may be a consideration, but in the author's experience, it never has been necessary to perform the surgery through a postauricular or endaural approach. In cases in which the patient has large osteomas or exostosis, these were removed through a postauricular approach, and the stapedectomy was performed at the
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 9, NO 2 (JUN), 1998: PP 68-71
same time. The mobility of the tympanic membrane is checked with pneumotoscopy to rule out serous effusion as a cause of the conductive hearing loss. Occasionally a reddish blush can be observed in the area of the anterior oval window. This is called a Schwartze sign and is due to the increased vascular supply to the active otospongiotic focus near the oval window. If there are any questions of the standard otoscopy, the ear is examined using the operating microscope in the office. In the case of revision surgery, there may be more problems with the tympanic membrane. Care is taken to inspect the posterior superior quadrant for possible retraction or perforation. Occasionally, the prosthesis can be observed on the undersurface or protruding through the tympanic membrane. Tuning forks are an important aspect of our evaluation and are performed on all patients. The Weber test will lateralize to the ear with the greater conductive hearing loss. With the 512 Hz tuning fork, bone conduction is greater than air conduction when the air bone gap is >15 to 20 dB. Bone conduction is greater than air conduction with the 1,024 Hz tuning fork when the air bone gap is more than 25 to 30 dB. We will not perform a stapedectomy on a patient if they do not reverse at least the 512 Hz tuning fork regardless of the results of the audiogram.
AUDIOMETRY All patients undergo an audiometric evaluation, induding air conduction, bone conduction and speech audiometry, performed by an audiologist. It is important in unilateral cases to use the appropriate masking. Typically, the patient with otosclerosis has good bone conduction with a significant air-bone gap. Speech discrimination is good and the speech reception threshold roughly matches the four frequency (500, 1,000, 2,000 and 3,000 Hz) speech average. Generally a minimum air-bone gap would be at least 20 dB. However, as previously stated, we rely greatly on our tuning fork test results. Therefore, at times we perform surgery if the patient reverses the forks, but the audiogram shows a minimal air-bone gap. In these cases we find postoperatively, there is an improvement in the bone conduction when compared with the preoperative bone conduction. Generally we do not perform tympanometry as part of our preoperative evaluation. The shape of the tympanogram is nondiagnostic, and the classic findings are a normal tympanogram and static compliance accompanied by absent ipsilateral and contralateral acoustic reflexes.
INDICATIONS FOR REVISION SURGERY The usual reason for revision stapedectomy is a significant conductive hearing loss. Occasionally, there are other indications for revision surgery. VERTIGO With small fenestra stapedectomies, vertigo is rare. Generally, we do not perform revision surgery on patients who have immediate postoperative vertigo. In cases of delayed vertigo, revision may be indicated to rule out and possibly repair a perilymph fistula (rare). Some patients complain of brief vertigo when they burp, Valsalva, or push on the ear. This can be an indication of a long prosthesis. JOHN W. HOUSE
DISTORTION On rare occasions some patients report distortion in hearing with some sounds. I have found that at revision surgery the wire is loose on the incus and tightening it relieves this annoying symptom.
SURGERY Before any surgery the patient in counseled about the risks, complications, and alternatives. If the surgery is being performed for a hearing loss, the patient is informed about hearing aids as an alternative to surgery. If there is any question regarding surge13~ the patient is advised to have a trial of hearing aids before the surgery is performed. The risks and expected results are different for revision surgery when compared with primary stapedectomy. We expect at least a 90% chance of significant gain in hearing to within 10 dB of the bone conduction. With revision surger~ the chance of this gain in hearing is only about 80%. In addition, the chance of further hearing loss is greater. We normally tell our stapedectomy patients that there is less than a 2% chance of further hearing loss and less than 1% chance of total hearing loss. With revision surgery, the patient is told that the chances of these poor results are somewhat higher. In all revision surgeries, the author keeps the KTP laser available, and a small area above the ear is shaved in case temporalis fascia is needed. It is imperative to have various prostheses available. These include all lengths of pistons and total ossicular prostheses (TOPs/TORPs). Along with having the laser available a microdrill is on hand in case the footplate needs to be drilled. ANTICIPATED FINDINGS In my experience, the most common finding at revision surgery is a laterally displaced prosthesis that has come off of the incus and out of the oval window fenestra. In these cases the prosthesis is changed, the fenestration reopened, and the prosthesis replaced. The next most common cause is an eroded long process of the incus that will no longer support a prosthesis. In these cases, the incus and stapes footplate are removed and a TOP over perichondrium is used for the reconstruction. A less common finding is a solid footplate. It may be that the first surgeon had a floating footplate and placed the prosthesis from the incus to the footplate. It subsequently refixed. A hint at what we might find is to ask if the patient had an initial improvement in hearing or not. If not, it may be that the stapes footplate was not removed. In the author's experience, there have been many interesting findings. Recently, there was a case in which there was a stapes prosthesis attached to the incus and extending into the area of the footplate. The stapes superstructure was still in place and firmly fixed. In this situation, the prosthesis was removed, a fenestra performed, the prosthesis placed, and the stapes superstructure removed. In other cases, the stapes footplate was intact and fixed despite several previous procedures.
SURGICAL TECHNIQUE The following is a brief description of the author's routine stapedectomy technique. The surgery is performed under local anesthesia with preoperative sedation. A standard tympanomeatal incision is performed and the middle ear 69
FIGURE 3. The piston is placed from the incus to the fenestra before removal of the superstructure.
FIGURE 1. The currette is used to remove posterior superior bony canal wat to obtain better visualization of the stapes.
entered. Usually the posterior superior canal wall is curetted for exposure of the oval window (Fig 1). Adequate exposure is achieved when the facial nerve and pyramidal process are visualized. The malleus, incus, and stapes are
palpated. The distance from the incus to the footplate is measured. With the stapes superstructure in place, a 0.7-mm diamond is used to create a fenestra in the center of footplate (Fig 2). At times, the part of the posterior crura is partially or totally removed with the drill. With the stapes in place, a 0.6-mm Teflon platinum prosthesis is placed from the incus to the fenestra and crimped onto the incus (Fig 3). The incudal stapedial joint is cut, the stapedial tendon is cut, the stapes superstructure fractured inferiorly and removed.
i
FIGURE 2. The microdrill and 0.7-mm diamond burr create a fenestra in the center of the stapes footplate. The fenestra is created before removing the stapes superstructure. 70
REVISION STAPEDECTOMY
Almost all of our revision surgery is performed using local anesthesia. This is especially important with revision surgery, because we want to know if the patient experiences any vertigo during the manipulation of the prosthesis or tissue in the oval window. If the patient reports vertigo, this may indicate adhesions extending into the vestibule to the saccule. Pulling out the soft tissue or prosthesis could result in a sensorineural hearing loss or vertigo. The standard tympanomeatal flap is elevated and the middle ear entered. Typically, the chorda tympani nerve is adherent to the undersurface of the tympanic membrane and therefore must be cut. We have found that sectioning the nerve causes less taste disturbance than when the nerve is stretched. Frequently, there are adhesions in the middle ear. These can be sectioned with middle ear scissors or the laser. The incus is identified and the previous prosthesis searched for. When the prosthesis is seen, it must be determined if it is still attached to the incus, and if it is in the oval window or vestibule. In my experience, the most common cause of failure is the prosthesis coming off of the incus with or without incus necrosis. In these cases, the distal end of the prosthesis is usually out of the fenestra. The prosthesis is carefully removed and the oval window carefully inspected. When tissue covers the footptate or oval window, it must be removed to determine if the footplate is intact, absent, or if there is a fenestra present. Generally, this tissue is best removed using a laser. If the membrane can be identified and is thin, it is not necessary to remove it. The author will make a small opening in it to enter the vestibule. A piston is placed from the incus to this newly created fenestra. If the footplate is found to be intact and fixed, a standard 0.7-mm fenestra is performed with the diamond drill and a 0.6-mm prosthesis placed. When the incus is necrotic and short, one of two techniques is used. In both techniques, the entire footplate is removed and the oval window covered with perichondrium. At times, a total ossicular prosthesis is placed from the tympanic membrane with interposition cartilage to the
JOHN W. HOUSE
oval window. In these cases, the remaining incus is removed. On other occasions, the author uses a prosthesis which has an off set and can be placed from the remaining Incus to the oval window. On several occasions, the author has found the prosthesis has slipped off of the incus and entered the vestibule. When a wire loop has been used for the primary surgery, it is best to leave it in the vestibule and possibly reconstruct with fascia over the oval window and a piston prosthesis. When a Teflon piston had been used, it is safe to carefully remove it, because membranous structures will not adhere to this type of prosthesis, This is also true with the polyethylene struts that were used in the early 1960s. They were abandoned because they tended to slip into the vestibule causing nerve loss or vertigo. The key to revision surgery is having available all the necessary prosthesis and tools, such as the laser, to be able to correct any condition that one might encounter.
SUMMARY In summar~ revision stapes surgery can be safely performed. The key factors are a careful history, physical examination (including tuning forks), and audiometry. The surgery is best performed under local anesthesia and the patient instructed to inform the surgeon if h e / s h e experiences any dizziness or vertigo. A laser is helpful in removing scar tissue from the oval window. It is important to assess the status of the oval wIndow and footplate, if present. The middle ear sound conducting mechanism is reconstructed according to the findings at revision surgery. Even though the results with revision surgery are not as good as primary surger~ the outcome does make doing revision surgery worthwhile.
REFERENCE 1. House JW,ShellyJL,Antennas JC: Stapedectornyin children. Laryngoscope90:1804-1809,1980
71