------------------------------------------------------------------------------- TITLE: OTOSCLEROSIS: DIAGNOSIS AND MANAGEMENT SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: MARCH 17, 1993 RESIDENT PHYSICIAN: Joseph J. Bradfield, M.D. FACULTY: Chester. L. Strunk, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. -------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." I. Historical Aspects A. Valsalva in 1735 described ankylosis of the margin of the stapes to the oval window on autopsy of a deaf patient. B. Toynbee in 1841 concluded after dissections of over 1600 ears, that ankylosis of the stapes was a common cause of deafness. C. Von Troltsch was the first to use the term sclerosis in 1881 based on the mistaken belief that sclerotic changes in the middle ear mucosa were responsible for the findings. D. Politzer corrected this misinformation in 1893 - concluding "stapes ankylosis is in reality a primary disease of the labyrinthine capsule. E. Seibenmann in 1912 proposed the correct name "otospongiosis" for the disease process, noting that the diseased bone was more porous and less dense than the normal bony otic capsule. F. Kessel is credited with the first attempt at stapes mobilization in 1878. G. Boucheron and Miot in 1888-1890 reported several hundred cases of mobilization. Best results were obtained in early cases. Blake performed the first stapedectomy in 1892 in Boston. In 1899 Faraci described his 30 cases of mobilization. H. At the 1900 International Congress, Seibenmann, Politzer and others condemned mobilization as useless and dangerous. The reasons for this vigorous position remain unclear - but stapes mobilization procedures ceased for almost half a century. I. By 1952 several things had occurred to pave the way for the resumption of stapes procedures: 1. The success of Lempert's fenestration procedure (1938) helped overcome the bias against surgery for otospongiosis. 2. Antibiotic drugs became available. 3. Improvement in audiometric techniques allowed quantification of results. 4. Lempert's endomeatal approach provided access to the middle ear cleft without tympanic membrane perforation. J. Rosen in 1952 revived the mobilization procedure - palpating the stapes and attempting to mobilize it prior to fenestration. K. Shambaugh in 1954 utilized the operating microscope to facilitate mobilization. L. In 1954, Shea revived the stapedectomy operation, realizing the need to close the oval window and restore ossicular continuity. M. Since then numerous variations on Shea's procedure have been employed, with various types of prostheses, instruments and methods of sealing the oval window. II. Etiology of Otosclerosis A. Hard, avascular bony otic capsule lacks bone remodelling and turnover unlike other parts of the skeleton. B. Ossification of the capsule occurs from 14 centers during the 16-23 weeks of fetal life. As ossification continues, a thin layer of endosteal bone is laid down lining the labyrinth, while a thicker layer of periosteal bone is laid down surrounding the endochondral capsule. C. The primitive endochondral capsule may persist unchanged from before birth until death. The capsule is felt to maintain the configuration of the cochlea, vestibule and semicircular canals, and to serve a protective function, protecting the inner ear fluids which bathe the hair cells from contamination from the toxic enzymes of bone resorption (collagenase and trypsin). D. Otosclerosis arises in this avascular endochondral bone, it is felt that the new bone formation of otospongiosis may be a response to devitalized bone, removing the dead bone and replacing it with vascular periosteal type bone subject to continued bony turnover. E. Hydrolytic enzymes are released by the remodelling process from osteoclasts and histiocytes, dissolve collagen and osteocytes causing the focus of otospongiosis to expand. F. This theory was supported by the work of Chevance, Causse and Berges in France whom found that the enzymes of bone resorption were in the perilymph of otosclerosis patients. III. Pathology of Otosclerosis A. Gross appearance: 1. Immature, active form: Thickened vascular mucosa, pinkish hue of promontory (Schwartze's sign). 2. Mature and active form: Whiter, chalklike in color compared with surrounding yellow normal capsule, distorted anatomy of the oval window niche. 3. Size: few mm confined to an area just in front of the oval window, to an extensive focus involving the promontory and narrowing the round window niche. B. Microscopic appearance closely resembles the appearance of new bone anywhere in the body. 1. Active form: vascular spaces contain fibrous tissue with osteoblasts and osteoclasts forming loosely knit bone, the vascular spaces become narrower and obliterated by dense compact bone. 2. A sharply defined border of otosclerosis may show fingerlike projections along blood vessels into normal adjacent capsule. A mantle of blue staining bone may be seen around these vessels. These mantles are thought to represent the earliest stage of the process. 3. Inactive form: Final stage: formation of mosaic pattern of highly mineralized bone. Osteoclasts have disappeared, osteoblasts and osteocytes still present. Vascular spaces narrowed, obliterated by new bone formation, healing stage in which lamellar bone formed is very thick and cellular versus normal. D. Sites of involvement: 1. The anterior stapedial footplate area, just anterior to the oval window area is involved in 80-90% of cases. 2. Second most common site is the region of the round window, evidence of otosclerosis here in 40-50%. 3. Both lesions tend to remain isolated, but may merge in 12% of cases. 4. Third most common site of involvement is the internal auditory canal, other sites include the otic capsule, the carotid canal, the cochleariform process, malleus and incus. 5. Half the involved ears will have a single focus, half will have multiple foci. 6. Bilateral involvement is found in 70-85% of patients. There is a tendency toward symmetry in size and location of the lesions. IV. Demographical Features A. Genetic analyses suggest a monohybrid autosomal dominant mode of inheritance with 20-40% penetrance. B. The disorder is most common among Caucasians, with 0.5 - 2% with clinical otosclerosis, rare in Orientals, American Indians and Blacks. C. Silent disease is 10 times more prevalent that clinically apparent, so the actual prevalence is difficult to specify. However autopsy studies demonstrate otosclerosis in 7.3% of male and 10.3% of female caucasian temporal bones. D. Female to male ratio is 2:1, in clinical practice. E. In India more males than females are affected. The disorder is half as common in Japanese as in Caucasians. F. Similar audiometric losses have been found in twins. V. Natural History of The Disease A. Onset is in late childhood, frequency increases until mid-adulthood. Shambaugh found an average age of onset of hearing loss in his series was 20 years, few cases less than 12 years of age, few cases had onset in middle age. B. In studies on series of fenestration patients who have been followed over long periods of time, sensorineural hearing loss developes in most but not all patients, the loss is usually disproportionate to the patients age. The hearing loss tends to progress in a stepwise fashion with periods of stability alternating with progression. C. There is increased activity of the disease at the time of puberty, pregnancy and menopause. With any one pregnancy there is a 1 in 4 chance that a woman with stapedial otosclerosis will experience an increase in hearing loss. VI. Clinical Diagnosis: A. Features: 1. History: slowly increasing bilateral hearing loss with one ear preceding the other in onset and severity. a. 50% of patients have one or more family members affected with hearing loss. b. Unilateral in 15% of cases. 2. Increasing air-bone gap by audio to a maximum conductive component of 50dB. 3. Tuning forks: Rinne progressively becomes negative first for 256 Hz. then 512 Hz then 1024 Hz as fixation becomes complete. 4. Hearing loss is usually not noted by the patient until it reaches about 25-30 dB. 5. Sensorineural hearing loss is variable but is present in most patients, disproportionate to age. 6. Audiometry also reveals Carhart's notch, which represents a loss of bone conduction at 2KHz induced by stapes fixation, most of the inertial component of bone conduction is secondary to the weight of the malleus and incus, this is lost with fixation. 7. Speech discrimination remains good unless there is an advanced sensorineural hearing loss or superimposed endolymphatic hydrops. 8. Paracusis willisi: If there is predominant conductive hearing loss without a sensorineural component, patients will report that hearing is improved in the presence of background noise. People with normal hearing will raise their voices above the level of background noise to remove the masking effect of noise. This level of speech may be above the threshold of the patient with the conductive hearing loss. People talk louder in noise! 8. Tinnitus: It is occasionally the presenting symptom, common in early stages of the disease, and can occur without cochlear degeneration but it usually indicates a SNHL. Can disappear when the lesion matures. Usually described as a ringing. 9. Vertigo: Attacks tend to be transient, and are not uncommon. They are felt to be the result of the action of toxic enzymes, liberated by the focus of otospongiosis on the labyrinth. a. The most common vestibular symptoms are recurrent attacks of vertigo and postural imbalance. b. One series reported 57% of patients had hypoactive calorics. c. Consider coexistent Meniere's disease if vertigo is a predominant symptom. B. Differential Diagnosis: 1. Serous otitis media 2. Middle ear fibrosis, adhesive OM, and fibro-osseous footplate fixation: ossicular fixation to the tegmen from healing from trauma or infection comprises 1% of the cases os CHL in patients with normaal TMs. 3. Tympanosclerosis 4. Ossicular discontinuity a. History of prior OM or truama b. NO Carhart notch c. Type Ad tympanograms 5. Congenital footplate fixation results from failure of the footplate to separate from the otic capsule. a. May be associated with a small TM, short manubrium of the malleus and partial meatal atresia, facial nerve course abnormal b. In this case the deafness will not progress c. Surgery should be considered with caution due to the potentially aberrant facial nerve and the risk of perilymph gusher. 6. Congenital fixation of the malleus and incus a. Usually associated with a developmental aplasia of the ear with meatal atresia, occasionally seen without meatal atresia, rare. 7. Osteoarthritis of the ossicular chain a. May involve the entire chain b. Difficult to distinguish from otosclerosis c. Commonly unilateral 8. Congenital Cholesteatoma: a. CHL in a child with a normal appearing TM and no effusion b. CT demonstrates mass. 9. Paget's Disease of Bone a. Temporal bone is involved in 50% of patients with clinical disease. b. Onset occurs after age 45 years. c. Diagnosis is by radiography, increased serum alkaline phosphatase and urine hydroxyproline. d. Early features: Conductive hearing loss with a high frequency SNHL and intact stapedial reflexes. e. Cause of the Conductive hearing loss is ossicular fixation usually of the malleus, there is no histologic evidence of stapes fixation, thus stapedectomy not beneficial. 10. Osteogenesis Imperfecta a. Autosomal dominant, hereditary disorder of collagen. b. Tendency to have multiple fractures of the long bones and calvarium with poor healing, blue sclerae and deafness. c. Onset of deafness about age 6 years, with a peak in 30's. d. The conductive hearing loss is more severe than in otosclerosis, greater SNHL. e. Etiology: Healing of microscopic footplate fractures with fixation of the stapes. f. Treatment is stapedectomy, operation must be delayed until all spontaneous fractures have ceased for many years. There is a high percentage of floating footplates. g. Thin long process of the incus, and degenerative changes of the crural arch, easily fractured long process of the incus. h. Increased likelihood of SNHL after surgery. VII. Cochlear Otosclerosis - Sensorineural Hearing Loss 1. Sensorineural hearing loss may accompany the CHL in otosclerosis or may occur as an isolated finding. 2. Theories of etiology of SNHL in otosclerosis: a. Bony invasion of the scala tympani of the cochlea. b. Circulatory changes to the cochlea, vascular shunts with venous congestion and hyperemia as a result of abnormal bony foci. c. Damage to the cochlea by toxic metabolites of bone resorption. (humoral theory) 3. The best evidence exists for the humoral theory as the cause of SNHL. a. Can have small foci of otospongiosis not reaching the endosteum, with the presence of a SNHL. b. May have total replacement of the cochlear capsule by otospongiosis with normal cochlear function. c. Vascular changes (shunts) with SNHL in otosclerotic patients are only seen in far advanced disease, and do not explain the losses seen with small foci. d. Causse, Chevance and others in 1960, provided further evidence of the humoral theory. They noted fibroblasts, fibrocytes, osteoblasts and osteocytes and histiocytes containing lysosomes filled with high enzymatic content, found in a focus of otospongiosis. Perilymph analysis in patients undergoing stapedectomy revealed several enzymes found in the lysosomes. Proteases enter the labyrinthine fluids in approximately 75% of cases which corresponds with a 75% incidence of cochlear degeneration seen in clinical stapedial otospongiosis. Statistical correlations have been established between the proteolytic activity of the perilymph and progressive SNHL. e. Hydrolytic enzymes and proteases causing cellular destruction spread from the original focus to different parts of the cochlea and labyrinth, depending on where the focus lies and where the enzyme is released will account for an individual patients symptoms. f. Trypsin and its inhibitors - alpha 1 antitrypsin and alpha 2 macroglobulin are usually found in a state of equilibrium. Chevance felt that there was an upsetting of the enzyme/anti-enzyme balance in otosclerosis leading to a SNHL possibly secondary to a genetic or an immune abnormality. 4. Diagnosis of Cochlear otosclerosis: Shambaugh a. Positive Schwartze's sign in one or both ears b. Positive family history of surgically confirmed otosclerosis c. Symmetric or progressive SNHL in both ears with early or advanced stapes fixation in one ear. d. A flat, "cookie bite" rising, or descending audiometric curve with unusually good speech discrimination for a pure SNHL. e. Pure SNHL beginning at the usual age for stapedial fixation and progressing without other discernable etiology. f. Tomography shows clearly defined demineralization of the cochlear capsule (not always seen and not necessary for diagnosis). g. Impedance: Early "on-off" effect, later type As. 5. Other features: a. Greater degree of SNHL in otosclerosis pts. than in the general population (Kellemen and Linthicum). b. Radiography: (Valvassori) obliterated, oval window is larger, more opaque density. VII. Medical Treatment - Sodium Fluoride A. Debate over the efficacy of NaF is ongoing. Detractors point out that there have been no good controlled studies that demonstrate the drug's efficacy, and warn of potential side effects. Proponents argue such studies are unnecessary and expensive. They point out the extensive data regarding efficacy and note almost 35,000 patients without permanent harm. B. Shambaugh and Scott (1964)demonstrated that NaF in moderate doses promoted recalcification and reduced bone remodelling in an active focus. C. NaF was less effective on mature lesions. D. Fluoride replaces the hydroxyl ion of hydroxyapatite crystals, the fluoride-apatite crystals are more dense, less soluble and more resistant to enzymatic bone resorption, osteoblasts are stimulated to produce bony matrix. If NaF is given without Calcium it leads to poor mineralization, and osteomalacia. E. Treatment increases the fluoride content of the focus, with increased radiolabelled calcium uptake. F. Anti-enzymatic action on proteolytic enzymes cytotoxic to the cochlea, converts otospongiotic bone to less active or inactive otosclerotic type bone. (Causse and Chevance) G. Evidence of the effectiveness of NaF: 1. Fading of Schwartze's sign 2. Stabilization of progressive SNHL in 80% of treated patients. 3. Reduces tinnitus 4. Improves vestibular symptoms 5. Recalcification is seen on radiographs 6. Decrease in the enzymes of bone resorption seen in the perilymph. H. Indications for use of NaF 1. Surgically confirmed otosclerosis, SNHL disproportionate to age 2. Pure SNHL with a history, age of onset, audiometric findings and good discrimination indicating cochlear otosclerosis. 3. Positive radiographic findings 4. Positive Schwartze's sign 5. Pre-operative administration: Causse follows his patients with otosclerosis for 2 years by audiometry before stapedectomy, if there is a progression of the SNHL, NaF is given before surgery 6. Other clinicians would administer preoperatively if there was a progressive SNHL over the previous 12 months. 7. If an active focus is found at the time of surgery, the patient is treated with NaF for 2 years. I. Contraindications: 1. Chronic nephritis 2. Arthritis 3. Pregnancy or lactation 4. Children before skeletal growth is complete 5. Prior allergy to NaF J. Results of Treatment (Shambaugh and Causse - 1974) 1. In a series of 4000 patients, 80% had stabilization of their SNHL 2. Few patients demonstrated recovery of their hearing, most had slow progression K. Dosage: Fluorical (8.3mg NaF + 364mg CaC03) ii caps po TID until the hearing has stabilized then i po TID for life. L. Side effects: 1. Gastric disturbance 2. Joint symptoms 3. Fluorosis of the spine in 0.25% IX. Surgical Treatment A. Indications: 1. Stapes firmly fixed as indicated by an air-bone gap of 30-40 dB for the speech frequencies, a negative Rinne for 256 Hz, 512 Hz, and sometimes 1024 Hz. (Shambaugh) 2. Bone conduction of 0-25 Db in the speech range, 45-65 Db in air conduction, an air-bone gap of at least 15 dB, Speech discrimination of greater than 60% (Goodhill) 3. The poorer hearing ear should be addressed first in cases of bilateral disease. 4. Useful for improving hearing aid usage in the presence of stapes fixation with profound SNHL if good discrimination. 5. In a small number of cases of profound SNHL secondary to otosclerosis, Wiet et all (1987) reported on the results of stapedectomy with postoperative hearing aid rehabilitation versus cochlear implantation, and found that stapedectomy was the preferred treatment. B. Surgical Contraindications 1. Poor general medical condition 2. Old age: in one series, in patients greater than 60 years of age, 22.4% of the patients had a poorer postoperative speech discrimination, in the group greater than 70 years, 40% had a poorer post-operative discrimination. There are reports of increased risk of fistula formation in the elderly age groups greater than 55 years. 3. Other causes of Conductive hearing loss, stapedectomy for tympanosclerosis - poor results, high incidence of gradual SNHL, malleus or incus fixation, dislocation or erosion. 4. Only hearing ear unless deafness becomes so profound that hearing aid use is ineffective. 5. Evidence of endolymphatic hydrops, increased risk of a dead ear from saccular distension which may impinge upon the footplate and be damaged from surgery, there have been reports of successful stapedectomy after sac decompression. 6. Otitis externa or media, TM perforation until they are successfully treated because of the risk of labyrinthitis and subsequent meningitis. 7. Active otosclerosis, pregnancy, occupation associated with considerable physical strain (risk of post-op fistula), airmen flying in unpressurized aircraft. 8. Minimal conductive hearing losses, some clinicians would consider stapes mobilization. 9. Children - tend to have more severs disease than adults. Surgery contraindicated even if fixation felt to be secondary to otosclerosis and not congenital fixation, hearing aids should be prescribed until adolescence and the situation if reviewed. 10. Unilateral otosclerosis: surgery may not be necessary, some may find the loss of binaural hearing handicapping, in this case operation may be justified. Hall et al. (1990) even in subjects that have normal thresholds restored through surgery, that some patients maintained abnormally poor binaural hearing, and prediction of post-surgical results from presurgical assessment was often underestimated. a. Patient should have pre-op bone conduction levels between 0-30 dB, have a negative 512 Hz. Rinne test, and a discrimination score of greater than 80% b. Optimal results are obtained only if thresholds in both ears are nearly equal postoperatively. 11. Prior stapedectomy a. Results less dramatic and more subtle than the first ear, with little improvement in overall hearing. b. Improving sound perception close to the involved ear and slightly improving localization may disappoint some patients. c. Only operate on the second ear if the functional result in the first ear was good and the hearing stable, a 1 year period between procedures is appropriate. d. Contraindicated if delayed SNHL in the first ear or permanent vestibular injury 12. Anatomic abnormality: exostoses, stenosis 13. Paget's disease C. Surgical Procedures 1. Stapedectomy a. Wide fenestra - (posterior 1/2 or more of footplate removed) (1) Less postoperative vertigo, and better high frequency hearing than total stapedectomy (2) Gelfoam should not be used to seal the oval window - higher risk of granuloma, fitula and reoccurrence of CHL. c. Small fenestra stapedectomy (1) Less postoperative vertigo and better high frequency hearing especially at 4K where there is better closure of the A-B gap, much of the consonants of speech in higher frequencies thus better speech discrimination, better long term sensorineural function at 4K and reduced incidence of total SNHL (2) More precise than removal of 1/2 of the footplate, less risk of direct damage to the utricle and saccule, less critical effect of prosthesis length (3) Techniques: (a) Micropick (b) Microdrill (c) Laser stapedotomy: In comparison to conventional stapedotomy closure of the air bone gap to within 10 dB was accomplished in 91% of the laser treated group versus 73% of the conventional group. With greater vestibular symptoms being seen in the laser group 39% versus 12% (Silverstein et al 1989) (d) Laser results in less bleeding, is relatively atraumatic. Vestibular symptoms may be decreased by lower wattage setting and increased duration between bursts. May provide greater reliability and allow residents to match the results of the "masters". 2. Stapes Mobilization (1) Indicated for minimal fixation of the stapes and early hearing loss in the region of 0-30 dB 3. Fenestration operation (1) Of historical importance (2) Indicated in certain congenital anomalies which make stapedectomy impossible (a) Dehiscence of the facial nerve with bulging over the oval window, abnormal course of the facial nerve (b) Persistent stapedial artery (c) Regrowth of footplate otosclerosis with fixation of the prosthesis (d) Some congenital deformities of the ear. D. Intraoperative Contraindications 1. Persistent stapedial artery a. Can sometimes perform a small fenestra stapedotomy 2. Dehiscent, prolapsed facial nerve over the oval window 3. Excessive bleeding a. Avoid with stapedotomy technique b. Bleeding into the vestibule has been associated with SNHL 4. Unsuspected middle ear disease 5. Ossicular fixation other than the stapes E. Special Problems/Intraoperative Complications 1. Obliterative otosclerosis a. Requires drill-out of the footplate b. Footplate saucerized until blue area appears c. Blue area perforated and enlarged with a fine pick until an opening twice the size of a 0.6mm piston formed, tissue graft placed, prosthesis placed to extend about 0.5 mm into the vestibule. d. Risks include excessive bleeding, acoustic trauma, reclosure of window by otosclerosis e. Argon laser small fenestra stapedotomy with Endo-Otoprobe for obliterative otosclerosis found to close A-B gap to within 10 dB in 100% of cases in a small series. (Gherini et al 1990) 2. Floating footplate a. Close the ear and let the footplate refix and complete the operation in 2-3 months b. Can remove the floater by drilling a safety hole in the promontory margin of footplate to allow extraction. c. Can place a prosthesis against the floating footplate after sealing the oval window with a tissue graft. d. No attempts should be made to retrieve a submerged footplate. 3. Round window closure a. Attempts to open the round window are disappointing and often lead to a dead ear b. Stapedectomy can be performed resulting in some but not great hearing improvement 4. Fracture of the long process of the incus a. If at the tip can crimp the prosthesis above the fracture site and insert a folded tissue graft to promote adhesions b. If fractured close to the body, a malleus to oval window prosthesis should be placed 5. Perilymph gusher a. Seen with abnormally patent cochlear aqueduct b. Seen in cases of congenital fixation c. Prevent by recognition by placement of a control hole in the footplate. d. Treatment includes sealing the oval window with a tissue graft held in place by a prosthesis, followed by bedrest with elevation of the head of bed, and lumbar drain insertion e. Associated with a high incidence sensorineural hearing loss. F. Complications of Stapedectomy 1. TM perforation a. If seen at the time of surgery, can splint the edges with cigarette paper or a tissue graft b. Cause of a persistent conductive loss post-op 2. Ossicular chain injury 3. Facial nerve injury a. May occur during drilllout of obliterative otosclerosis b. Inflammatory state in post-op healing can cause a transient palsy starting on about POD #6 and lasting a few weeks. c. Treat like a Bells palsy, rarely decompression necessary 4. Cochlear damage: surgical trauma - due to suctioning, drill trauma,labyrinthine rupture, attempts to remove footplate fragments etc 5. Bony Annulus resection a. Can lead to adherence between the TM and the long process of the incus if too much resected G. Postoperative Complications 1. Suppurative labyrinthitis and meningitis a. Leads to a dead ear and absence of an ENG caloric response. b. Prevent by sealing the oval window with a large tissue graft and using prophylactic antibiotics c. If it occurs should immediately hospitalize the patient perform a lumbar puncture for CSF culture and sensitivity, place the patient on IV antibiotics, in rare cases surgical drainage is necessary. d. Most authors recommend prophylactic antibiotics. 2. Vertigo: a. Usually occurs at the time of prosthesis placement and is temporary, if it continues, the prosthesis may be too long and should be remeasured and replaced with a shorter one. If a prosthesis cannot be inserted without causing vertigo, the ear should be closed. Complete the procedure in 1-2 months. b. Can be secondary to vestibular end organ damage or a perilymph fistula. (1) End organ damage usually responds to labyrinthine exercises and slow improvement in symptoms should be noted week by week as compensation occurs. The other causes will have persistent vertigo until surgical treatment completed. 3. Facial Paralysis 4. Sensorineural or Conductive hearing loss 5. Tinnitus a. Usually clears after surgery b. Can be secondary to too long of a piston with excessive penetration into the vestibule or secondary to TM retraction pushing the piston into the vestibule c. Other causes include trauma to the endolabyrinthine membrane, acoustic trauma, cochlear otosclerosis. 6. Improper length of the prosthesis a. Associated with Meniere's like symptoms including tinnitus, imbalance and rotatory vertigo, a decrease in bone conduction is noted first for the low tones, with a shift in the WeBer towards the unoperated ear 7. Perilymphatic Fistula a. Probably the most frequent cause of immediate or late SNHL after stapedectomy. b. Symptoms include a fluctuating hearing loss, tinnitus, a feeling of fullness in the ear and imbalance or vertigo. May occur up to 15 years post operatively. c. Can detect by valsalva maneuvers, vertigo occurs when the patient blows his nose or when there is tragal compression or by the use of pneumatic otoscopy. d. Best method for detecting a fistula is the combination of impedance - bridge measurements with ENG. It is performed on a patient with closed eyes. Verify the absence of spontaneous nystagmus and positional nystagmus before testing. It is conducted by ENG recording after application of positive and negative pressure (400 mm H20). The patient is questioned about dizziness and vertigo. (1) If positive response - nystagmus, this is typically seen after stapedectomy (2) If a negative response - no nystagmus, this is seen in the presence of a perilymph fistula. e. Prevention: (1) Partial footplate removal (2) Tissue graft seal over opening of the oval window (3) Secured prosthesis to the incus (4) Avoid valsalva maneuvers, and flying for 10 days after surgery or whenever a URI present f. Treatment (1) Exploratory tympanotomy with removal of the prosthesis and replacement of tissue graft over the site. (2) If a fistula is not found, fluid leakage can be elicited by placement of the patient in Trendelenburg's position, Valsalva by the patient, jugular vein compression, positive pressure ventilation by the anesthesiologist. (3) Results of treatment for perilymphatic fistula: (a) Vertigo is improved or eliminated in 76-100% of patients (b) Hearing loss is improved or stabilized in 73-78%, Tinnitus persists in 87% (c) Results better if fistula repaired early g. Dry mouth and taste disturbance (1) Secondary to trauma to the chorda and are transient. H. Postoperative Sensorineural Hearing Loss 1. Early appearance after surgery: a. Granuloma (1) Occurs after 0.6 - 3% of stapedectomies (2) Most develop within 6 weeks of surgery (3) Presents as a gradual or sudden hearing loss or with vertigo (4) Exam reveals a red-gray discoloration posterosuperioly behind the TM (5) Audiogram reveals a SNHL with a decreased word discrimination (6) Treatment includes immediate exploratory tympanotomy to prevent the development of a serous labyrinthitis and permanent SNHL (7) Intra-op: red, soft, vascular mass extending from the niche around the prosthesis and long prosthesis. (8) The prosthesis is removed with the granuloma and a different graft material is placed. (9) Results: 20% complete recovery of hearing, partial in 30%, No change in 30% and further loss occurs in 20% b. Perilymph fistula c. Serous labyrinthitis 2. Late losses a. Perilymph fistula b. Dead ear c. Cochlear otosclerosis I. Postoperative Conductive Losses 1. Pressure necrosis of the incus 2. Prosthesis of inadequate length or disarticulated 3. Mucosal adhesions 4. Refixation of the footplate 5. TM perforation 6. Misdiagnosis J. Revision Surgery 1. Farrior reported the results of exploration in 109 cases of failed stapedectomy. The most common causes of failure were (in order): displaced prostheses, incus erosion, fistula, TM perforation, cholesteatoma, mobilization, fenestration, and malleus fixation. 2. Approximately 70% of patients will have improved hearing. 3. Higher incidence of partial or complete hearing loss than primary stapedectomy. 4. Preoperative vertigo is not relieved in revision surgery in approximately 75% of cases (Smyth 1975) -------------------------------------------------------------------------------- BIBLIOGRAPHY 1. Amedee, R.G. and Lewis, M.L.: Obliterative Otosclerosis; Laryngoscope: 99; p. 922-924. 2. Beales, P.: Otosclerosis; John Wright and Sons; Bristol 1981 3. Causse, J.B.: Surgery for Otosclerosis, Chapter 5 in Complications in Otolaryngology- Head and Neck Surgery. 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