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Revision Ossiculoplasty

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Otolaryngol Clin N Am 39 (2006) 699712

Revision OssiculoplastyRavi N. Samy, MD, FACS*, Myles L. Pensak, MD, FACSThe Neuroscience Institute, Department of Otolaryngology, University of Cincinnati/Cincinnati Childrens Hospital Medical Center, Cincinnati, OH, USA

Although ossiculoplasty was attempted initially in the early 1900s, it was not until the era of Wullstein [1] and Zollner [2] in the 1950s that it became commonplace and relatively well understood. Since then, there have been numerous technologic advances and a gain in the understanding of ossiculoplasty, also known as ossicular chain reconstruction (OCR). However, even in primary cases performed by an experienced otologic surgeon, successful OCR with resulting long-term stability can be a daunting task. This is even more true for the occasional otologic surgeon and for revision cases. Typically, the most common condition requiring revision OCR is chronic suppurative otitis media (COM) with or without cholesteatoma. Primary and revision OCR is performed also for blunt and penetrating traumainduced conductive hearing loss (CHL), congenital defects (eg, atresia), and benign and malignant tumors. Typically, reconstruction in ears with COM is more dicult than in ears without infection. The anatomic goal of OCR is to restore the middle ear transformer mechanism. OCR is not performed if cochlear function is poor, particularly with regards to word discrimination. OCR is also contraindicated in an only hearing ear; a hearing aid is the preferred option in this instance. Patients with bilateral CHL should have the worse hearing ear operated on rst; an alternative to this approach is to operate on the more diseased ear in patients with bilateral COM [3]. The goal of revision OCR is the same as for primary OCR: to obtain both objective (audiologic, clinical examination) and subjective success. Although some surgeons avoid revision OCR in the pediatric population because of concerns about the aggressive recurrence of chronic ear disease (particularly in those under the age of 5 years), others perform OCR to minimize the* Corresponding author. E-mail address: [email protected] (R.N. Samy). 0030-6665/06/$ - see front matter 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.otc.2006.05.005

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potential for decits in acquiring language and to improve speech production and school performance. Several issues must be considered before proceeding with revision OCR: Realistic expectations for the patient and surgeon, including chance for failure Eradication of chronic ear disease or cholesteatoma Possibility of staging to maximize chances of success Discussion of alternative methods of sound amplication (ie, hearing aids, including bone-anchored hearing aid (BAHA) placement) The only surgically attainable goal may be control of infection, particularly in revision procedures involving COM. In some patients, amplication may be indicated, instead of an attempt at revision OCR [3]. To maximize the chances of success of revision OCR, the surgeon must understand the factor or factors that may have contributed to failure of the initial OCR, including persistent or recurrent COM, excessive brosis, eustachian tube dysfunction (ETD), and poor surgical technique [4]. The surgeon must also consider each of the following anatomic factors as potential contributors to OCR failure, singly or in combination: middle ear, mastoid, tympanic membrane (TM), remnant ossicular chain, and type of prosthesis. However, success correlates more often to middle ear or mastoid pathology and aeration than to the prosthesis itself [5]. Preoperative evaluation and prognosis assessment A thorough preoperative history is performed rst. Comorbidities (eg, diabetes, coronary artery disease, and so forth) must be considered. The benets of surgery must outweigh the risks of surgery and anesthesia. Preoperative clearance by a primary care physician, specialist (eg, cardiologist), and anesthesiologist may be warranted. Patients are advised against smoking, to prevent postoperative wound healing complications and to eradicate the negative eect smoking has on eustachian tube function and middle ear disease [6]. All available outside records, including the prior operative report, should be reviewed. A detailed head and neck physical examination, with emphasis on the otologic portion, is performed. Otomicroscopic evaluation with pneumatic otoscopy and tuning fork tests is conducted. Detailed audiologic testing with pure-tone air and bone conduction, tympanometry, speech recognition, and word recognition is performed. In revision cases, CT scanning (in the axial and coronal planes, 0.5 mm or 1 mm cuts, and bone windows) is performed. The scan can assist in determining areas of tegmen erosion, facial nerve dehiscence, otic capsule erosion, and prosthesis position. MRI with gadolinium can be ordered if there is concern about encephalocele formation or impending intracranial complications. The chances of surgical success are related to the severity of pre-existing chronic ear disease, ETD, and other complicating factors. Stratication

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systems have been developed for prognosis and to compare results among patients, surgeons, and prostheses. Classication systems developed for prognostic purposes are used variably, and include factors such as middle ear disease (granulation tissue, eusion, otorrhea), smoking, presence of a perforation, cholesteatoma, ossicular defects, and previous surgery. The greater the number of adverse factors, the less the chance of a good postoperative hearing result. These patients may do much better with a hearing aid. The goal of a classication system is to improve preoperative assessment and prognostication for an individual patient, and to allow better comparisons among dierent prostheses, surgeons, and for research and reporting purposes. One such method of assessment was reported by Black [7] in 1992, who reviewed 535 ossiculoplasties. He identied 12 features and divided them into ve groups: S-surgical, P-prosthetic, I-infection, Ttissue, E-Eustachian tube (SPITE). He compared the results for his patients implanted with plastipore prostheses with the results for those implanted with hydroxylapatite (HA) prostheses; he found no signicant dierence between the two groups, when accounting for the dierent factors. Eustachian tube A properly functioning eustachian tube is the most important factor in the creation and maintenance of aeration in the middle ear space. Without adequate eustachian tube function, one cannot obtain a long-term improvement in hearing results with revision OCR. Adequate eustachian tube function ultimately will determine the size of the middle ear space. The minimal amount of air required in the middle ear space for OCR is approximately 0.4 mL. The type of surgical approach used also aects middle ear volume (and the size of the prosthesis needed). For example, canal wall down techniques narrow the middle ear space. ETD contributes to OCR failure by narrowing the middle ear space and contributing to prosthesis extrusion. Methods to treat and improve ETD include treatment of allergies, laryngopharyngeal reux, smoking, and obstruction of the middle ear and nasopharyngeal orices (eg, due to granulation tissue/hypertrophic mucosa and adenoid hypertrophy, respectively). Direct medical or surgical treatment of the eustachian tube to improve function has been proposed (eg, tuboplasty); however, it remains to be seen whether these options will adequately treat this elusive problem for the long term. Another option to alleviate ETD is to place a ventilation tube at the time of OCR or postoperatively, if needed. Some surgeons tend to avoid placement of ventilation tubes because of the possibility of increased risk of otorrhea and the need for water precautions. Although ETD plays the most important role in chronic ear disease and aects OCR results, no manner exists in which to quantify eustachian tube function objectively. Evaluation of contralateral ear function, assessment of TM position and mobility, the existence of retraction pockets, the ability of

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the patient to insuate the middle ear (Valsalva maneuver), or forced movement of air through the eustachian tube (politzerization) can all be used in the assessment. Middle ear and mastoid disease Another key factor in successful revision OCR is the appropriate treatment of middle ear and mastoid ear disease, such as hypertrophic mucosa, granulation tissue, debris, tympanosclerosis, adhesions, brosis, and cholesteatoma. Surgical eradication of the pathologic processes may reduce the risk of recurrence by removing biolm formation, including that formed by Pseudomonas. In chronic ear disease, eradication of disease takes precedence over reconstruction of the hearing mechanism. Residual or recurrent ear pathology can cause failure of prosthesis placement by causing prosthesis extrusion, displacing the TM, or eroding the remnant ossicular chain. Active COM can cause a resorptive osteitis of the ossicles [3]. Tympanic membrane The TM can contribute to OCR failure through lateralization or retraction. TM perforations also contribute to failure. TM perforation that occurs secondary to the prosthesis is probably caused by pressure necrosis and not a reaction to the prosthesis itself [8]. Some surgeons use cartilage to minimize TM-related complications (Fig. 1). Cartilage can be used in reconstruction to minimize medialization of the TM (by increasing the stiness of the TM), reduce the incidence of prosthesis extrusion, and minimize the chance of recurrent retraction pocket formation and the subsequent creation of cholesteatoma. Martin and colleagues [9] reported on 180 subjects who underwent TM reconstruction with cartilage, fascia, or perichondrium. Afte

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