Revision tympanomastoid surgery. (Original Article).

Abstract

We conducted a retrospective study of 50 ears in 48 patients in whom we performed revision tympanomastoid surgery for chronic otitis media. We found that the most common probable causes for the failure of previous surgery were incomplete lowering of the facial ridge (94% of cases), persistent sinodural-angle air-cell disease (92%), persistent tegmental air-cell disease (88%), recurrent or persistent cholesteatoma (66%), persistent mastoid-tip air-cell disease (62%), a small meatus (60%), and persistent hypotympanic air-cell disease (56%). After a mean postoperative follow-up of 26 months, we found no appreciable difference in success rates between patients who had undergone only one previous surgery (93%) and those who had undergone more than one previous surgery (95%) prior to referral to our center. Follow-up hearing data revealed a statistically significant improvement in air and bone conduction and a nonsignificant reduction in the air-bone gap. We conclude that revision mastoid surgery following multiple earlier surgical failures does not carry an appreciably higher risk of failure than does initial revision surgery. Moreover, there appears to have been no change in the causes of failure following mastoid surgery over the past 3 decades.

Introduction

The goals of surgery for otitis media are universal and have been clearly articulated in the past. (1) The mandates for the surgeon include removal of disease (e.g., infection and cholesteatoma) in the middle ear and in the mastoid cavity as well as reconstruction of the area in a manner designed to minimize the risk of recurrent disease. It is also desirable to maximize hearing postoperatively and to avoid injury to important neurovascular structures.

The literature is replete with reports on the merits of the two major surgical procedures that address these problems: the canal-wall-down (open-cavity) techniques and the canal-wall-up (closed-cavity) techniques, with or without second-look surgery. (1-4) What is sometimes overlooked in discussions of the various surgical approaches is the significant rate of failure or recidivism. (4) Failure might be the result of recurrent or persistent cholesteatoma or persistent infection and suppuration following surgery for chronic otitis media with or without cholesteatoma. (3)

The otologic literature contains a variety of reports describing the incidence of postoperative infection or drainage in the ear following mastoidectomy. (1-4) The success of tympanomastoid surgery, therefore, has been defined as the attainment of a dry ear postoperatively. Various authors have reported success rates in the range of 70 to 95%. (4) A number of articles have identified a subset of surgical factors that serve as hallmarks of a classic "problem cavity," or discharging mastoid bowl. (5,6) The problem cavity is likely to exhibit a number of findings that are believed to be responsible for failure. (6) These findings include a small meatus, a high facial ridge, a persistent bony canal wall, a partially removed attic wall, a deep mastoid cavity, and a failure of a drum graft attributable to diseased mucosa and/or active mucopurulent drainage. (6)

In 1974, Brandow delineated four major factors that he believed are responsible for continued cavity suppuration. (7) These factors are (1) a failure to completely eradicate the original disease, (2) the inability of the cavity to cleanse itself, resulting in an accumulation of excessive debris, (3) persistence of an open eustachian tube, resulting in exposure of the middle ear mucosa, and (4) infection of the skin that lines the mastoid cavity.

In 1978, Cheesman analyzed the causes of surgical failure in 141 patients with chronic otitis media who later required revision surgery. (8) Of the initial failed operations, 75% were canal-wall-down procedures. Cheesman found that the four leading causes of failure and the impetus behind revision surgery were (1) an inadequate cartilaginous meatoplasty, (2) a high facial ridge, (3) inadequate management of air-cell disease, and (4) a failure to exteriorize all cholesteatoma.

In 1985, Nadol reviewed the operative findings in 66 patients who underwent revision mastoid surgery and found recurrent cholesteatoma in 45% of them. (1) He then reviewed the anatomic location of persistent granulation tissue and found that 41% of cases harbored granulation tissue in tegmental air cells and 38% demonstrated involvement of sinodural-angle air cells. Of those patients who had undergone previous canal-wall-down surgery, 34% had a high facial ridge. Nadol reported that revision surgery was successful in 85% of patients who had previously undergone one to three primary mastoid procedures.

For our study, we analyzed a consecutive series of patients who had been referred to us for revision surgery after previous mastoid surgery had failed. Our goals were to ascertain the likely causes of the previous failures and to identify the sites of unexenterated air cells in the tympanomastoid cavity. We also compared our findings with those of similar studies conducted during the 1970s and 1980s to test the hypothesis that the causes of failure have not changed over the past 3 decades. Most important, we sought to determine if there was any difference in surgical outcomes (i.e., dry ear vs draining ear) between patients who underwent revision surgery for the first time and those who had undergone mastoid surgery after one or more failed revision attempts. Finally, we attempted to identify the overall effects that successful revision mastoid surgery had on hearing and to illustrate the variety of challenging issues that face the surgeon who performs revision mastoid surgery.

Patients and methods

We retrospectively reviewed the outcomes of 48 consecutive patients who had been referred to our institution for revision mastoidectomy. We had performed 50 revisions (46 unilateral and two bilateral) in the 48 patients--30 males and 18 females, aged 7 to 71 years (mean: 39.2)--over a 5-year period from 1995 through 1999. The 50 ears had undergone a total of 86 previous surgeries (range: 1 to 5; mean: 1.7). Twenty ears had undergone more than one previous surgery.

We tabulated data on the location of persistent air-cell disease, the presence or absence of cholesteatoma, and the significant mechanical factors that contributed to recurrent symptoms. We also analyzed the results of all available pre- and postoperative hearing evaluations.

One of the authors (C.A.M.) performed all of the revision procedures described in this study. Patients were treated with one of three revision techniques: (1) tympanomastoid obliteration, (2) a canal-wall-up procedure, or (3) a canal-wall-down procedure. The latter included (1) removal of all air cells at the level of the tegmen, sinodural angle, and mastoid tip, (2) canaloplasty, including removal of tegmental air cells to the level of the tegmen tympani and anteriorly to the temporomandibular joint, and (3) lowering of the facial ridge to the level of the facial nerve. Care was taken to leave a thin shell of bone over the facial nerve. The facial ridge was lowered inferiorly at the level of the digastric ridge to allow for unencumbered communication between the mastoid bowl and the meatus (figure 1). Formal meatoplasty, including removal of conchal cartilage, was also performed. Tympanoplasty (type 3 or 4) and total drum replacement (with temporalis fascia) was followed by split-thickness skin grafting. The grafting procedure included obliteration of the mastoid cavity with muscle pedicle flaps or, in some cases, bone pate. Type 1 tympanoplasty was performed in canal-wall-up procedures. Facial nerve function was monitored, and prophylactic antibiotics were routinely administered to all patients.

We studied the postoperative course following all 50 procedures up until the time that a clean and dry ear was achieved. Postoperative audiologic follow-up data were available on 39 of the 50 ears. Outcomes were assessed by comparing pure-tone averages (500 to 2,000 Hz and 500 to 4,000 Hz) and individual pure tones (250 to 8,000 Hz) before and after revision surgery. The two-tailed Student's t test was used for statistical analysis.

Among the 11 patients (all of whom underwent unilateral procedures) for whom audiologic follow-up data were not available, three patients had undergone tympanomastoid obliteration (two of whom had a profound sensorineural hearing loss as a result of previous surgery), four were affected with severe developmental delay and therefore evaluation of their behavioral thresholds was not possible, two were surgical failures who later went on to further revision surgery, and two were lost to follow-up prior to formal postoperative audiology.

Results

The length of the clinical and audiologic follow-up ranged from 1.5 to 49 months (mean: 26). A successful outcome was defined as the attainment of a clean, dry, well-epithelialized cavity with no persistent or recurrent cholesteatoma, drainage, or granulation tissue. Overall, 47 of the 50 revision surgeries (94%) met these criteria for success. There was no appreciable difference in success rates between those who had undergone only one previous surgery and those who had undergone more than one. Of the 30 ears that had undergone only one previous surgery, success was achieved in 28(93%). Among the 20 ears that underwent more than one previous surgery, 19 (95%) were treated successfully.

Types of revision surgery. During previous surgery, 32 of the 50 ears (64%) had been treated with a canal-wall-down procedure and 18 (36%) with a canal-wall-up procedure. During revision surgery, 42 ears (84%) were treated with a canal-wall-down procedure, five (10%) with a canal-wail-up procedure, and three (6%) with a canal-wall-down procedure followed by tympanomastoid obliteration with abdominal fat. At our initial evaluation, 48 of the 50 ears exhibited otorrhea (two of which required urgent care) and the other two were marked by severe debris accumulation. In addition, we also noted eight cases of severe complications of chronic otitis media following previous surgery (table 1).

Intraoperative findings. During previous surgery, 48 of the 50 ears (96%) exhibited cholesteatoma; during revision surgery, 33 (66%) had recurrent or persistent cholesteatoma. Intraoperative findings of concern included nine instances of facial nerve dehiscence (18%), one case of horizontal semicircular canal fistula (recurrent cholesteatoma) (2%), and 18 cases of tegmental dural dehiscence (36%), two of which required concomitant middle fossa craniotomy and dural repair with a bone graft (figure 2).

Intraoperative findings of interest during revision surgery were the presence or absence of cholesteatoma, the site of persistent air-cell disease, and the presence or absence of a small meatus or a high facial ridge. The most common finding on revision surgery thought to be causally related to the previous surgical failure was an incomplete lowering of the facial ridge, which was seen in 30 of the 32 cases (94%) that had previously been treated by a canal-wall-down procedure (table 2). Other possible causes of both canal-wall-up and -down failures in all 50 ears were persistent sinodural-angle air-cell disease (46/50 [92%]), persistent tegmental air-cell disease (44/50 [88%]), recurrent or persistent cholesteatoma (33/50 [66%]), persistent mastoid-tip air-cell disease (31/50 [62%]), a small meatus (30/50 [60%]), and persistent hypotympanic aircell disease (28/50 [56%]). In addition, 41 of the 50 ears (82%) had a failed drum graft.

Hearing data. The group as a whole experienced a statistically significant improvement in air and bone conduction (figure 3, table 3). These patients also demonstrated a reduction in the mean air-bone gap, but this improvement was not statistically significant.

Complications of revision surgery. Only two complications of revision surgery were noted. One patient developed a postoperative wound infection that required intravenous antibiotics; the infection subsequently resolved. Another patient developed a hematoma following tympanomastoid obliteration secondary to a rapid escalation of warfarin. The hematoma resolved after surgical debridement and placement of a muscle flap. There was no case of iatrogenic labyrinthine or facial nerve injury or iatrogenic postoperative sensorineural hearing loss.

Discussion

Revision surgery for chronic otitis media is clearly a more complicated and potentially risky undertaking than is primary surgery. In this series, there was a 16% incidence (8 of 50 ears) of significant complications noted upon referral to our clinic. These complications included profound sensorineural hearing loss in two ears, two cases of facial paralysis, and conditions related to the loss of dural integrity. Cottrell and Pulec found similar complications in 740 patients who had undergone radical or modified radical mastoidectomy at Mayo Clinic. (9) Management of these issues at the time of revision surgery was enhanced by routine preoperative computed tomography (CT). During our revision surgery, dural dehiscence(36% of cases) and facial nerve vulnerability as a result of dehiscence (18%) were common, and thus they should be anticipated.

When looking at persistent unexenterated air cells in the mastoid system, 92% of cases had persistent diseased air cells in the sinodural angle and 88% had persistent disease involving tegmental air cells; substantially fewer patients had problematic air cells at the level of the mastoid tip or hypotympanum. It is unclear whether these findings alone or in combination with the additional mechanical issues noted at the time of surgery were the causes of failure and persistent drainage. However, it is likely that the combined findings of a high facial ridge, a small meatus, and a failed drum graft were contributory.

In our study, 26 of the 32 cases (81%) that had been previously treated by canal-wall-down surgery were found to involve an inadequate meatus. A high facial ridge was found to be a complicating factor in 30 of these 32 cases (94%). Also, 41 of the 50 ears (82%) had a failed drum graft. It is likely, then, that surgical failures were caused by the totality of these technical factors and not by merely one factor in and of itself. Others have noted this in the past and have indicated that these conditions are additional risk factors for a postoperative wet ear. (10) Although it is likely that these technical causes of failure are all contributory, it appears that the most common cause is a high facial ridge. It is likely that lowering the facial ridge reduces the incidence of these additional factors.

The extent of surgical exenteration during primary or revision surgery with regard to uninvolved or uninfected air cells is controversial. Brandow advocated that areas of infected or diseased bone should be removed, although he wrote that "it is not necessary to look for and remove all noninfected cells." (7) In a review of causes of surgical failure in chronic ear surgery, Cheesman noted that most otologists agreed that diseased cells should be removed, but he pointed out that there was a lack of agreement regarding the management of the remaining healthy cells. (8) He wrote that it might not be necessary or practical to remove every cell, especially if the drainage system remains uninterrupted postoperatively. However, during canal-wall-down surgery that includes the creation of a cavum minor and interruption of normal mastoid drainage, Cheesman believed that it was necessary to "achieve total removal of all mastoid air cells except those not disturbed by the cavity reconstruction." He stressed the need for attention to the sinodural-angle air cells, the posterior and lateral perilabyrinthine air cells, and the cells in the mastoid tip.

In a large study by Jackson et al in 1996, the problem cavity was marked by numerous other mechanical issues. (11) Although they are not listed here in order of their prevalence in revision cases, these issues include problems with a small meatus, a high facial ridge, a dependent mastoid tip, tympanic membrane perforation, granulation tissue, and retained cholesteatoma. In our series, all of these findings were significant contributors. The occurrence of failed drum grafts that we noted on revision surgery, however, was not limited to canal-wall-down surgeries; failed grafts complicated approximately 80% of both canal-wall-up and canal-wall-down procedures.

It is possible that the constellation of technical problems described in this and other reports occurs in a cascade during surgery. For example, failure to exenterate epitympanic tegmental air cells leaves disease in the attic region and possibly contributes to the eventual failure of the drum graft superiorly. Similarly, failure to lower the facial ridge to the level of the facial nerve in the posteroinferior annular region might leave disease or trapped cells at the level of the hypotympanum, which can lead to granulation tissue and subsequent failure of the drum graft inferiorly. It is likely that a failure to "skeletonize" the sinodural angle and unmask diseased tegmental air cells leaves behind diseased labyrinthine air cells and obscures persistent cholesteatoma; these failures are often associated with the finding of disease in the posterior epitympanum. Therefore, it is possible that central to the many factors that complicate the chronically draining postoperative ear is the failure during initial su rgery, and in some cases during revision surgery, to remove all air cells, whether they are diseased or undiseased. In sum, the causes of failure noted in reports of revision mastoid surgery during the 1970s and 1980s appear to be the same as they are today.

It is interesting that the number of previous surgeries in this study did not appear to put the patient at greater risk of failure. There was no appreciable difference in success rates between those who had undergone only one previous surgery and those who had undergone more than one (93 and 95%, respectively).

Although the primary goal of this type of procedure is to create a clean, dry, and safe ear, the need to retain hearing is also significant. (12) The hearing data in this report reflect short-term (mean: 26 mo) findings. Nevertheless, the audiologic findings were encouraging, and they suggest that an improvement in hearing rather than mere preservation is a realistic expectation.

Two weaknesses of our study are that the size of the sample was relatively small and the duration of follow-up was relatively short. Nevertheless, neither of these limitations hindered our goal of highlighting and documenting the outcomes differences between primary and secondary revision mastoid surgeries.

[FIGURE 3 OMITTED]

Table 1. Severe complications of chronic otitis media following previous
surgery

Complication                         n

Profound sensorineural hearing loss  2

Acute mastoiditis                    1

Facial paralysis (chronic)           1

Facial paralysis (acute) with        1
 recurrent cholesteatoma

Meningoencephalocele                 1

Meningoencephalocele with            1 *
 intracranial cholesteatoma and
 seizure

Sigmoid sinus thrombosis and         1 *
 meningitis

* Urgent condition.
Table 2. Possible causes of failure of previous surgery in the 50 ears

                                     Canal-wall-down  Canal-wall-up
                                      (n = 32 [%])    (n = 18 [%])

High facial ridge                        30 (94)           N/A

Persistent sinodural-angle air-cell
disease                                  31 (97)         15 (83)

Persistent tegmental air-cell
disease                                  28 (88)         16 (89)

Recurrent or persistent
cholesteatoma                            20 (63)         13 (72)

Persistent mastoid-tip air-cell
disease                                  20 (63)         11 (61)

Small meatus                             26 (81)          4 (22)

Persistent hypotympanic air-cell
disease                                  20 (63)          8 (44)

                                        Total
                                     (n = 50 [%])

High facial ridge                        N/A

Persistent sinodural-angle air-cell
disease                                46 (92)

Persistent tegmental air-cell
disease                                44 (88)

Recurrent or persistent
cholesteatoma                          33 (66)

Persistent mastoid-tip air-cell
disease                                31 (62)

Small meatus                           30 (60)

Persistent hypotympanic air-cell
disease                                28 (56)
Table 3. Hearing results following revision surgery

                                      Mean      No.           Mean SD
Measurement                           (dB)   patients   SD *   error

Air PTA * (500 to 2,000 Hz)  Pre-op   50.21     39     18.18   2.91

                             Post-op  43.41     39     15.31   2.45

Air PTA (500 to 4,000 Hz)    Pre-op   53.14     39     19.02   3.04

                             Post-op  45.89     39     16.35   2.61

Bone PTA (500 to 4,000 Hz)   Pre-op   18.51     37     10.36    1.7

                             Post-op  15.90     37     11.17    1.8

Air-bone gap                 Pre-op   31.45     39     13.92   2.23

                             Post-op  28.33     39     12.91   2.06


Measurement                   p Value

Air PTA * (500 to 2,000 Hz)
                             p = 0.007


Air PTA (500 to 4,000 Hz)
                             p = 0.002


Bone PTA (500 to 4,000 Hz)
                             p = 0.048


Air-bone gap
                             p = 0.194


* SD = Standard deviation; PTA = Pure-tone average.

References

(1.) Nadol JB, Jr. Causes of failure of mastoidectomy for chronic otitis media. Laryngoscope 1985;95:410-3.

(2.) Kinney SE. Intact canal wall tympanoplasty with mastoidectomy for cholesteatoma: Long-term follow-up. Laryngoscope 1988;98:1190-4.

(3.) Males AG, Gray RF. Mastoid misery: Quantifying the distress in a radical cavity. Clin Otolaryngol 1991;16:12-4.

(4.) Merchant SN, Wang P, Jang CH, et al. Efficacy of tympanomastoid surgery for control of infection in active chronic otitis media. Laryngoscope 1997;107:872-7.

(5.) Wormald PJ, van Hasselt CA. A technique of mastoidectomy and meatoplasty that minimizes factors associated with a discharging mastoid cavity. Laryngoscope 1999;109:478-82.

(6.) Jackson CG, Glasscock ME III, Nissen AJ. et al. Open mastoid procedures: Contemporary indications and surgical technique. Laryngoscope 1985;95:1037-43.

(7.) Brandow EC, Jr. Revision surgery for the mastoid cavity. Otolaryngol Clin North Am 1974;7:41-56.

(8.) Cheesman AD. Changes in otological teaching following analysis of failures in surgical technique. Clin Otolaryngol 1978;3:233-7.

(9.) Cottrell RE, Pulec JL. Modified radical and radical mastoidectomy: Long-term results. Laryngoscope 1971;81:193-9.

(10.) Wormald PJ, Nilssen EL. The facial ridge and the discharging mastoid cavity. Laryngoscope 1998;108:92-6.

(11.) Jackson CG, Schall DG, Glasscock ME III, et al. A surgical solution for the difficult chronic ear. Am J Otol 1996;17:7-14.

(12.) Harvey SA, Fox MC. Relevant issues in revision canal-wall-down mastoidectomy. Otolaryngol Head Neck Surg 1999;121:18-22.

Reprint requests: Cliff A. Megerian, MD, Department of Otolaryngology--Head and Neck Surgery, University Hospitals of Cleveland, 11100 Euclid Ave., Cleveland, OH 44106. Phone: [phone]; fax: [phone]; e-mail: [e-mail]

Originally presented in part at the Eastern Section meeting of the Triologic Society; Pittsburgh; Jan. 30, 2000.