7 Tympanoplasty/Ossiculoplasty The fact that revision surgery results from failed primary surgery is obvious; however, the reasons for that failure and how to address them often are not. This chapter identifies the causes for failure of primary surgery, review the indications for revision surgery, discuss the increased risks of revision surgery, and offer suggestions to reduce the chances of another failure at reoperation. This chapter also discusses principles of revision tympanoplasty and ossiculoplasty separately even though the two are often performed at the same time as well as in staged procedures. Failure in tympanoplasty and ossiculoplasty is due to one of two reasons. The first reason relates to the art of surgery and includes patient selection, preoperative judgment, perioperative management, and intraoperative surgical technique. Increased skill, knowledge, and experience of the surgeon result in less chance for error in judgment and/or execution; the surgeon must keep abreast of new technology, maintain a competent skill level, and consider referral to a more experienced or specialized surgeon if the case requires it. The second reason for failure is the disease process itself. The overwhelming majority of cases of tympanoplasty and ossiculoplasty involve ears damaged by chronic otitis media. The operation occurs in a pathologic continuum that may or may not be altered permanently by surgical intervention. It is critical to remember this fact when counseling a patient preoperatively and when assessing postoperative results. As well as the otologic disease process, there are many nonotologic factors that can influence surgical outcome. Systematic diseases such as tuberculosis, diabetes, immunodeficiency syndromes, and craniofacial anomalies are but a few. Of major significance is respiratory disease, particularly that of an allergic or infectious nature. Smoking can be a significant cause for failure in some cases. Other factors, such as unhealthy diet, poor nutrition, poor health in general, noncompliance with medical treatment, and lifestyle choices, such as swimming and scuba diving, may also increase the chance for unsatisfactory results. It is important to evaluate a patient preoperatively with regard to the specific objectives of surgery. The often-stated objectives of chronic ear surgery are elimination of disease, creation of a dry, functional ear, and maintenance of or improvement in hearing. In most cases, the objectives are prioritized in the order presented. In other words, it is difficult to obtain a dry ear or improve hearing for any length of time if otologic disease is still present. Although these objectives are important in primary cases, they are critical in performing revision surgery. This chapter will address only tympanoplasty and ossiculoplasty; mastoidectomy is discussed in the following chapter. Most importantly, before considering whether revision surgery is indicated, whether the objectives of surgery can be met, or what revision procedure should be recommended, the surgeon must answer one simple question: Why did the previous surgery fail? Tympanoplasty failure can be classified as one of the following condition: reperforation, graft lateralization, or atelectasis. Of course, any or all can occur together. The success rate for tympanoplasty is considered quite high; it is usually reported as upwards of 90% in simple myringoplasty, although the failure rate is somewhat higher when associated with mastoid surgery, severe infections, or congenital anomalies.1,2 There may be a higher failure rate in children, although this is not universally agreed upon.3,4 Merchant et al stated that chronic otitis media with granulation tissue is much harder to control than chronic otitis media with cholesteatoma.5 The causes of reperforation may occur early or late. Early causes of reperforation are most often due to faulty technique; late causes of failure are usually due to infection or graft shrinkage.6 There are many reasons that could be attributed to faulty technique. Poorly constructed surgical incisions may have resulted in inadequate exposure of the tympanic membrane and surrounding structures, thus limiting visibility during the procedure. The graft may have been made too small, not allowing for shrinkage as the graft dries or heals. The recipient bed of the tympanic membrane remnant may have been prepared improperly by not creating a large enough surface for the graft to adhere to the recipient bed. In a large or total perforation with little or no anterior remnant, the graft may have been inserted improperly onto the bony external auditory canal, again, creating inadequate adherence. The graft may also have been placed improperly, allowing an edge to pull away from the supporting tympanic membrane remnant. It may not have been anchored sufficiently with packing or the various techniques to interpose the graft between skin and bone of the external canal. Faulty technical factors are almost infinite and, in reality, may not be readily identifiable in the postoperative analysis. Late causes of reperforation often relate to infection or graft atrophy. A preoperative infection may have been unrecognized and doomed the procedure to failure before it was even started. There may have been a postoperative hemorrhage or collection of fluid that caused the graft to pull away from supporting structures or reperforate. The graft itself may atrophy over time due to an infectious or autorejection process. Persistent middle ear disease is undeniably the most common factor underlying a late graft reperforation. Residual cholesteatoma, persistent mucosal disease, and disease in the mastoid cell system are major contributing factors. The common denominator for all middle ear disease is ultimately eustachian tube dysfunction; this fact is so basic that it seems almost trite to discuss it, yet it is necessary to emphasize this reason. Many of the failures of chronic ear surgery in general, and tympanoplasty in particular, relate to the inability to adequately solve this difficult physiological problem at the present time. Long-term follow-up in tympanoplasty surgery is important to monitor this complication, which may be asymptomatic in the early stage. Failure may also occur with graft lateralization. This most often occurs with the overlay technique of tympanic membrane grafting and is an inherent complication of the technique itself. Because the graft has been placed lateral to the tympanic membrane remnant, it can become displaced outwardly due to improper placement, hemorrhage, serous fluid collection, inadequate packing, or Valsalva effect in the immediate postoperative period. If lateralization occurs in the anterior portion of the tympanic membrane, these conditions can be the result of the anterior angle. Blunting in this area may also be caused by an iatrogenic cholesteatoma that results from incomplete removal of all squamous epithelium from the lateral surface of the anulus or tympanic membrane prior to placement of the graft. Lateralization of the graft can also occur when using an underlay technique or some modification thereof. The graft can slip from the tympanic membrane bed or not adhere to the malleus handle. Lateralization of the graft from the malleus long process may occur in the “over-under” technique, where the graft is placed “under” the anterior remnant but “over” the malleus handle. Graft lateralization creates insufficient conduction of sound through the transformer mechanism of the middle ear and can be quite difficult to reconstruct satisfactorily at a subsequent operation. Although lateral grafting techniques are excellent methods for tympanoplasty and are used widely by many surgeons, the technique itself causes this complication, and usually not the disease process. Paying meticulous attention to the details of graft placement, replacing the canal skin and/or flaps meticulously without any squamous epithelium turned under, and using firm packing material are technical ways to avoid this problem. By no means should these overlay techniques be abandoned, but avoidance of this inherent complication is obviously the best solution. The third way in which a tympanoplasty can fail is by postoperative atelectasis. This may be technical, caused by using too thin a graft, not reinforcing the graft with other materials, such as cartilage, using a thicker graft, or not ventilating the ear at the primary surgery. It is often an error in judgment not to stage the surgery. Thick Silastic sheeting can maintain the middle ear space while the tympanoplasty heals, to reduce the incidence of this complication. Although technical factors may play a role, the most common cause of postoperative atelectasis is the disease process, specifically, eustachian tube dysfunction. As mentioned previously, this is the underlying etiology of almost all chronic ear disease and is, unfortunately, without adequate solution at the present time. Atelectasis may also be due to weakening of the tympanic membrane from recurring infections, recurrent disease of the mastoid cell system, or the development of a monomeric tympanic membrane during the healing process. As with reperforation, long-term follow-up is critical to monitor the progression of atelectasis. It may be possible to reduce its incidence by ventilation of the middle ear in the postoperative period. Postoperative myringitis is another condition that should be considered to be a graft failure. Hearing may be satisfactory and the middle ear protected; however, the patient may complain of pain, fullness, or otorrhea. In actuality, this is a granular reaction of the lateral surface of the tympanic membrane graft. It can have an angry red or a velvety pink appearance. The etiology is uncertain, although an autoimmune response, reaction to topical agents used intraoperatively (including packing material), or a postoperative infection may be factors. If topical antibiotics, débridement, or silver nitrate cautery is not successful, revision tympanoplasty with excision of the diseased area may be necessary. Ossiculoplasty may fail for one of three basic reasons: a problem with the prosthesis, postoperative adhesions, and recurrent disease. The first cause of failure, a problem with the prosthesis, may be immediate or delayed. Immediate failure is most likely due to technical factors. The prosthesis may have been measured inappropriately; too long a prosthesis may lead to slippage or dislocation into the vestibule, and too short may lead to inadequate sound conduction. The ossicular remnant (malleus or stapes superstructure) to which the prosthesis is attached may erode. There may be an unrecognized fixation of the stapes footplate.7 Delayed failure can also be due to slippage of the prosthesis within the middle ear space.8 This can be from inadequate contact with supporting ossicles, scar tissue, adhesions, or tympanosclerosis. Extrusion of the prosthesis can occur with any implant and can result from a foreign body reaction to autograft, homograft, or synthetic biomaterial. Prosthesis extrusion can result from the disease process as well and may be due to collapse and adherence of the tympanic membrane/graft around the prosthesis and not actually due to the ossiculoplasty itself.8 Although this should be considered an extrusion, it relates more to otopathology than to the technical aspects of ossiculoplasty. The incidence of extrusion of a synthetic prosthesis may be reduced by using a cartilage interface between the prosthesis and the tympanic membrane graft. Unrelated, nonotologic events can cause the prosthesis to become displaced after proper insertion. These include postoperative head injury, trauma, and sports-related injuries (soccer, scuba diving, wrestling, etc.), as well as a simple sneeze or other Valsalva episodes, which are sometimes unavoidable. It is also possible to have a malfunction of the prosthesis by reabsorption. This is rather uncommon with most biomaterials, except with cartilage used to reconstruct the ossicular chain.9 Determination of which technical factor caused the failure in ossiculoplasty may be difficult or impossible; an accurate operative note or personal knowledge if the revision is accomplished by the initial surgeon is desirable. The patient’s history, however, will be helpful in identifying whether the lack of hearing improvement was immediate or delayed. A second cause of failure in ossiculoplasty is from postoperative adhesions in the middle ear. As with any epithelial surface in a cavity, the method of handling middle ear mucosa can create adhesions postoperatively. Bone dust, glove powder, or packing material itself can create a foreign body reaction that causes adhesions. Manipulation of the mucosa can create raw surface areas that will adhere to the graft material or opposing epithelium. The disease process itself, either recurrent or primary, can promote granulation tissue formation.5 Inadequate removal of diseased mucosa can create excessive scar tissue. Each of the conditions may promote adhesion formation. Modification in surgical technique can reduce the incidence of adhesions, but the underlying disease process will often create a situation where adhesions arise. Ossiculoplasty may also fail because of recurrent disease. A recurrent or residual cholesteatoma can displace a prosthesis or simply render it nonfunctional. The persistence of granulation tissue, reperforation of the tympanic membrane, or persisting otorrhea can cause a failure in ossiculoplasty. Atelectasis and nonaeration of the middle ear affect the transformer mechanism of the middle ear, although the ossiculoplasty itself may be intact. All of these conditions can also cause the prosthesis to become immobilized or to migrate or extrude. The causes of failure of tympanoplasty and ossiculoplasty have been considered separately, but obviously, many of the factors that affect one can affect the other. It is important to recognize the causes of failure when considering the indications for revision surgery. The indications for revision surgery relate to the objectives of surgery. The basic objectives for revision surgery are identical to those for primary surgery: eliminating residual disease, obtaining a dry, functional ear, and improving or maintaining hearing. It is just as critical at revision surgery (perhaps even more so) to consider the specific objectives of both the surgeon and the patient. Does the patient only want a dry ear at the expense of hearing improvement? Does the surgeon note residual or recurrent disease that must be addressed to prevent complications? Does the patient want to hear better, even if it means never swimming again? Answering these questions accurately is important in counseling the patient preoperatively and improves the chances of satisfactory surgical outcome. With these thoughts in mind, we will consider for each of the two procedures the indications for revision surgery and will try to identify noncorrectable causes of failure and, specifically, when not to reoperate. The indications for revision tympanoplasty are persisting otorrhea, hearing loss, reperforation, graft lateralization, atelectasis, and residual and/or recurrent disease. These factors must be considered with respect to the objectives just discussed to allow appropriate patient selection preoperatively.
Causes of Failure of Primary Surgery
Tympanoplasty
Ossiculoplasty
Indications for Revision Surgery
General
Tympanoplasty
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