Portuguese Version

Year:  2003  Vol. 69   Ed. 4 - (13º)

Artigo Original

Pages: 521 to 525

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Labyrinthine fístulae in chronic otitis media with cholesteatoma

Author(s): Norma O. Penido1,
Flávia A. Barros2,
Luiz C. N. Iha3,
Carlos E.C. Abreu3,
Rogério N. Silva4,
Sung W. Park4

Keywords: chronic otitis media with choleteatoma, labyrinthine fístulae, computed tomography

Abstract:
The chronic otitis media with cholesteatoma (COMC) may evoluate to intracranial and extra cranial complications, including the labyrithine fístulae. In this study, we present the evolution of our patients with labyrinthine fístulae. Study design: Clinical prospective. Material and Method: Ten out 82 patients with COMC had labyrinthine fístulae and underwent surgery from January/2001 to April/2002. They were assessed by clinical exam, computed tomography scans, and pre and postoperative audiogram. Results: Hearing loss, otorrhea, tinnitus and dizziness were present in 100%, 90%,80%, and 40% of the cases. In one patient the fístulae was seen only in the coronal CT-scan, in another patient the fístulae was not seen neither in coronal nor axial images. Among the patients who had tinnitus, 66% referred improvement of this complaint after surgery. Discussion: in the cases without invasion of the perilymphatic space, we noticed a tendency of improvement of the postoperative audiogram pattern and clinical outcome. In the extensive fístulae, on the other hand, there were no clinical changes. Conclusion: The CT-scan remains the best exam to assess the COMC with 90% of sensitivity for labyrinthine fístulae. In the stage II we had a good postoperative outcome.

INTRODUCTION

Chronic otitis media with cholesteatoma (COMC) is an otologic affection that can manifest intra and/or extracranial complications during its progression. In past decades as a result of the advent of effective antibiotic therapy and improvement of surgical and diagnostic techniques, the incidence of such complications has decreased significantly, but the incidence of labyrinthine fistula has remained constant at 3.6% to 12.8%, according to the literature 1, 2.

The lateral semicircular canal (CSL) is the most frequent location of labyrinthine fistulae, which may be accompanied by other affected structures, such as the superior and posterior semicircular canals or, more rarely, the cochlea 3, 4, 5.

The clinical presentation is varied: some fistulae are asymptomatic whereas others are associated with varied grades of auditory and vestibular disorders.

Among the assessment methods for patients with chronic otitis media (COM), high resolution computed tomography scan (CT scan) is the most widely used, diagnosing cholesteatoma, bone ossicle chain involvement, labyrinthine fistula and facial nerve canal defects. However, the sensitivity of this test varies according to the involved structures.

The treatment of labyrinthine fistula is controversial concerning the surgical technique (open or closed mastoidectomy), partial or complete removal of the matrix and, in some cases, the material used for sealing.

The present study aimed at correlating the clinical audiological and radiological assessment of patients with treatment in cases of COMC with labyrinthine fistula, confirmed intraoperatively.

MATERIAL AND METHOD

We conducted a retrospective study in the period between January 2001 and April 2002, reviewing 82 patients operated on owing to COMC, being that 10 of them presented labyrinthine fistula diagnosed intraoperatively at the Service of Otorhinolaryngology, Federal University of Sao Paulo, Escola Paulista de Medicina.
Our sample included:

 10 patients;
 7 men and 3 women;
 Ages between 13 and 70 years.

All patients were submitted to complete ENT examination and CT scan, pure tone audiometry, speech discrimination test and immittanciometry with contralateral stapedial reflex, pre and postoperatively.

Pure tone audiometry was conducted in the following frequencies: air conduction 250 Hz - 500 Hz - 1000 Hz - 2000 Hz - 3000 Hz - 4000 Hz - 6000 Hz and 8000 Hz and bone conduction 500 Hz - 1000 Hz - 2000 Hz - 3000 Hz - 4000 Hz. We also performed Speech Reception Threshold (SRT) and Speech Recognition Index (SRI). The audiometer used was brand MAICO MA 41.

We followed the classification by Davis and Silverman, 1970, to define the grades of hearing loss (mean of 500-1000-2000 Hz).

 Normal - 0-25dB HL
 Mild - 26-40 dB HL
 Moderate - 41-70 dB HL
 Severe - 71-90 dB HL
 Profound - > 91 dB HL

CT scan was performed with device Phillips Tomoscan, using the high-resolution mode with sections and 1mm increments at axial and coronal sections.

Surgical description was obtained by reviewing the medical charts of the patients. It was possible to analyze the surgical technique, the fistula site and its treatment.

Fistulae were classified concerning degree of bone erosion of the labyrinth 6 (Table 1).

Figure 1. Axial section: Absence of fistula.



Figure 2. Coronal section of the same patient: lateral semicircular canal fistula.

RESULTS

The ten patients with labyrinthine fistula presented cholesteatoma. The clinical picture involved hearing loss, otorrhea, tinnitus and labyrinth symptoms in 100%, 90%, 80% and 40% of the cases, respectively (Table 2).

The CT scan of patients at axial and coronal sections were assessed by emphasizing the semicircular canals and the cochlea.

We detected fistula of the lateral semicircular canal in 8 patients at axial and coronal sections, being that in 3 patients we also visualized affection of the vestibule; two of these patients had damage of the superior semicircular canal, being that in one there was associated affection of the basal cochlear turn. In one patient, the finding of fistula was only made by coronal section (Figures 1 and 2).

In one patient we did not detect the fistula in the CT scan (Table 3).

Among the nine cases that had preoperative tinnitus, three still reported tinnitus postoperatively, being that two of them were still operated on only for one month.

Based on the surgical descriptions, we could analyze the mastoidectomy technique described, as well as the management concerning the fistula. The data were compared to pre and postoperative audiometry findings and vestibular symptoms (Table 4).

Table 1. Classification of degree of fistula.



Table 2. Preoperative symptoms.



Table 3. CT scan - Location of the labyrinthine fistula.

CSL: Lateral Semicircular Canal
CSS: Superior Semicircular Canal
Vest: Vestibule


Table 4. Surgery, pre and postoperative audiometry findings and vestibular symptoms.

VA= air conduction; VO= bone conduction; CSL= lateral semicircular canal; CSS= superior semicircular canal

DISCUSSION

The assessment of labyrinthine fistulae caused by cholesteatoma remains undefined, being that preoperative diagnosis is not possible in all cases.

The presence of vertigo associated with otorrhea and sensorineural loss can lead to suspicion of labyrinth involvement, however, in our sample we observed only 40% of the patients with vestibular symptoms, similarly to the literature findings 7.

High resolution CT scan is considered the preferred exam for assessment of COMC presenting high sensitivity to identify soft part tissues and bone erosion of the middle ear structures, but with limitations in identifying labyrinth damage 8.

In our study, we could not detect the number of false-positive cases, because we included only patients with surgical diagnosis of fistula, but we observed two cases of false negative, one only at the axial sections (grade II erosion fistula) and the other at both sections (grade III erosion fistula).

These results are in accordance with the literature and show that CT scan, concerning labyrinthine fistula, has limited sensitivity. Some authors justify this failure by the positioning of the patient and the level of the section, since smaller lesions than 2mm are not evidenced 7.

The audiometric findings in our patients showed a directly proportional correlation with fistula grade. All patients with endosteum lesions (equal or greater than 3) were anacusic in the preoperative assessment. In the three patients without endosteum lesion, but with its exposure, we detected cochlear reserve. Among them, none presented loss bone conduction greater than 50 dB. The results are related to the grade of hearing loss with the observed destruction, which agrees with the data in the literature 9, 10.

The surgical technique, in turn, is the most controversial topic in the literature. Considerations about the type of mastoidectomy, open or closed, and the complete or incomplete removal of the cholesteatoma matrix are issues still under discussion. Such questions are based on the destructive nature of the cholesteatoma and the risk of cochleovestibular function loss. Some authors advocate the idea that the preservation of the matrix of the cholesteatoma predisposes to the progression of the disease, thus, indicate that complete removal be performed to avoid possible complications 11. Conversely, others emphasize that the preservation of the matrix over the fistula with exteriorization through the open cavity would protect labyrinth functions 12, 13.

In our service, we normally conducted open mastoidectomy in cases of cholesteatoma with labyrinth involvement owing to the social-economic characteristics of the population, which has high prevalence of cholesteatoma of large extension at the first diagnosis. Owing to the referred reasons, the adoption of a second look becomes impossible.

To choose fistula treatment between removing the matrix or not, and in case of removal, the material to be employed to close the fistula, we should take into consideration the level of hearing impairment ipsi and contralateral to the affected ear and the size of the fistula. In grade II fistula, we advocate the use of bone wax, whereas in more advanced grades, the material to be used is varied, and it can be fascia, muscle, fat or bone patte. In extensive fistulae, with remains of ipsilateral hearing or fistulae of any degree in one single ear, our management is to maintain the matrix to avoid hearing loss.

The postoperative audiometric results showed that patients that had grade II fistula with erosion achieved the best thresholds, whereas patients that presented grades III and IV did not have improvement, which suggested that integrity of the endosteum is important to preserve the cochlear reserve. The only patient that presented auditory reserve 9 maintained the hearing loss level.
Preoperative vestibular symptoms were reported in only four patients. The distribution did not vary according to fistula grade. Out of the total, two cases presented improvement of symptoms, one maintained vertigo with partial improvement and the other died.

Patient 5 came to the ER with peripheral facial paralysis on the left, vertigo and hypoacusis. We diagnosed cholesteatoma and he was submitted to radical mastoidectomy whose intraoperative finding revealed fistula of the lateral semicircular canal and vestibule, with purulent discharge from the labyrinth. After intralabyrinth injection with gentamicin, the vestibule was sealed with muscle and the semicircular canal was sealed with bone wax. The patient was administered ceftriaxone during hospitalization and he was discharged and improved considerably using axetil-cefuroxime. Later on, he progressed with fulminant bacterial meningitis, intracranial hypertension and death within few hours after hospitalization.

CONCLUSION

CT scan continuous to be the preferred test for assessing patients with COMC but the diagnosis of labyrinthine fistula in some cases is made only intraoperatively. In our sample, we had one case of fistula observed in the surgery, in which CT was not conclusive.

The surgeon should always be attentive to the possible presence of a fistula, because one of the most important causes of deafness is failure to diagnose intraoperative fistula.

We found a correlation between audiometric pattern and extension of the fistula. In cases in which the endosteum was not involved, we considered it timely to remove the matrix of the cholesteatoma and to use bone wax, because we observed improvement of the audiometric pattern in our patients. In more extensive fistulae, the removal of the cholesteatoma matrix should be conditioned to absence of cochlear reserve. In anacusic patients, we decided to remove the matrix, because the risk of complications in the central nervous system is high.

REFERENCES

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1. Affiliated Professor, Department of Otorhinolaryngology and Human Communication Disorders, Federal University of Sao Paulo - Escola Paulista de Medicina.
2. Master studies in Otorhinolaryngology under course, Federal University of Sao Paulo - Escola Paulista de Medicina.
3. Master studies in Otorhinolaryngology and Head and Neck Surgery under course, Federal University of Sao Paulo - Escola Paulista de Medicina.
4. Specialist in Otorhinolaryngology and Head and Neck Surgery, Federal University of Sao Paulo - Escola Paulista de Medicina.
Department of Otorhinolaryngology and Human Communication Disorders - Federal University of Sao Paulo - Escola Paulista de Medicina.
Rua René Zamlutti 160 apt. 131 Chácara Klabin - Sao Paulo SP Brazil 04116-260
Tel: 55 11-5573-1388/ 55 11-9608-9796.
Study presented at 36 º Congresso Brasileiro de Otorrinolaringologia, in Florianópolis, held on November 19 - 23, 2002.
Article submitted on April 15, 2003. Article accepted on July 01, 2003.

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