Keywords
Chronic Disease - Otitis Media - Hearing Loss - Cholesteatoma - Middle Ear - Reoperation
Introduction
Otitis media is defined as an inflammatory disease of the middle ear that may be infectious
or not and focal or generalized. The course of disease may be acute with a tendency
towards total resolution and a return to the integrity of the regions affected, or
it may be chronic with permanent sequelae[1]
[2]
[3].
Chronic otitis media (COM) is clinically characterized as an inflammatory condition
associated with otorrhea and tympanic membrane perforation in some cases. The disease
course is more than 3 months in duration and histopathologically it is associated
with irreversible tissue changes.
The incidence of COM is higher in less developed countries. Malnutrition, poor hygiene,
poor quality housing, and high population density are factors that are associated
with a higher incidence of middle ear infections[3]
[4].
COM can be subdivided into two groups: cholesteatomatous chronic otitis media (CCOM)
and chronic otitis media without cholesteatoma (COMWC). A central or marginal perforation
may be present. The inflammatory process in the middle ear mucosa may show different
stages of evolution.
CCOM is characterized by epithelial accumulation with keratin production in the middle
ear. Cholesteatoma may be classified as congenital or acquired, and is further categorized
as primary or secondary cholesteatoma. Clinical and surgical treatments are available
for COM. The first is reserved for COMWC when patient follow-up is possible. The surgical
approach is suitable for both CCOM and COMWC and encompasses tympanoplasty, canal
wall-up (CWU) and canal wall-down (CWD) mastoidectomy[1]
[5]
[6] and its variations, including modified radical mastoidectomy or Bondy's procedure.
The choice of technique remains controversial and is usually decided based on the
presence or absence of cholesteatoma, its location, the state of the middle ear mucosa,
and auditory thresholds. Recurrence and post-operative functional status vary between
techniques.
The aim of this study was to clarify which surgical technique provides the best outcomes
in terms of disease control and improved hearing thresholds.
Method
This was a retrospective study of an historical cohort. The medical records of patients
with COM who underwent a CWU or CWD mastoidectomy at the otorhinolaryngology department
of a tertiary hospital between 1997 and 2005 were evaluated.
Postoperative outcomes for the 2 techniques mentioned above were compared using control
of the disease, absence of otorrhea, and cholesteatoma recurrence during the follow-up
period, which was at least 24 months, as criteria. Pure tone average hearing thresholds
at 500 Hz, 1000 Hz, and 2000 Hz were also compared before and after surgery for both
techniques.
Statistical analyses were performed using the Chi square test, and p values <0.05
were considered statistically significant.
Inclusion criteria: Patients of both sexes who were over 14 years of age, diagnosed
with COM, had undergone a CWU or CWD mastoidectomy with preoperative and postoperative
audiometry, and who were followed up for at least 2 years.
Exclusion criteria: Patients with sensorineural hearing loss, exposure to occupational
noise, previous ear surgery, history of head trauma, or with a suspected perilymphatic
fistula were excluded. The study was approved by the Ethics in Research Committee
(number: 098/07).
Results
A total of 88 patients (33 men and 55 women) were selected for the study. Their average
age was 30 years (standard deviation, 15.17) with a minimum age of 14 and a maximum
age of 78. The average period of postoperative follow up of these patients was 7.5
years.
In the group of 39 patients with CCOM, 20 (51.3%) had undergone a CWD mastoidectomy.
Three (15%) of these patients required a second surgery due to persistent otorrhea.
Of the 19 (48.7%) patients who underwent a CWU mastoidectomy, 11 (57.9%) required
a further operation, 8 due to the recurrence of a cholesteatoma and 3 due to persistent
otorrhea.
Of the 49 individuals with COMWC, 8 (16.6%) underwent a CWD mastoidectomy, and 2 (25%)
of these required a further operation due to persistent otorrhea. Of the 41 (84.4%)
patients who underwent a CWU mastoidectomy, 5 (12.2%) required further surgery, including
4 for persistent otorrhea and 1 due to the evolution of cholesteatoma.
When the CWU and CWD techniques were compared among the patients with CCOM, a higher
rate of disease control and the absence of otorrhea and cholesteatoma were associated
with the CWD technique (p < 0.05).
There were no statistically significant pre- or postoperative differences in the pure
tone average thresholds at 500 Hz, 1000 Hz, and 2000 Hz between the techniques.
Discussion
Among the patients with COMWC, the disease control rate was 91.9%, regardless of the
technique used, which is similar to the rates reported in other studies, which have
ranged from 63% to 96%[7]
[8]
[9]
[10]. Among the patients with CCOM, the disease control rate was 64.1%, which is slightly
lower than previous reports, which have ranged from 75% to 90%[7]
[11]
[12]
[13].
When the CWU technique was used, the disease control rate for the first surgery was
76.6%. In contrast, when the CWD technique was used, the disease control rate was
85.7%, regardless of the presence of cholesteatoma. Data in the literature are similar
with reported values ranging from 71% to 95% for the CWU technique[9]
[11]
[14]
[15]
[16] and from 71% to 96% for the CWD technique[9]
[11]
[13]
[14]
[15]
[16].
In the COMWC group, a higher rate of revision surgery was found among patients who
underwent a CWD mastoidectomy (25%) compared with a CWU mastoidectomy (12.2%). This
can be explained by the fact that patients with more severe disease were selected
for CWD mastoidectomy.
Of the patients with CCOM who underwent a CWU mastoidectomy, 57.9% required revision
surgery whereas only 15% of those who underwent a CWD mastoidectomy required revision
surgery. The current literature also shows higher recurrence rates when patients with
cholesteatoma undergo a CWU mastoidectomy. Cruz et al. (2001) reported surgical revision
rates of 37.5% and 26.08% when using the CWU and CWD techniques, respectively. We
believe that in our study the higher rate of reoperation observed when preserving
the canal wall is related to the longer follow-up (median 7.5 years), and suggests
late complications of the disease, which are not uncommon when the CWU technique is
used.
The choice of technique remains controversial but this study, in agreement with the
literature, has shown that cholesteatoma can be treated with the CWU technique. However,
Bento et al. and Cruz et al.[14]
[5] suggest that criteria such as cholesteatoma restricted to the attic, good condition
of the middle ear mucosa, and the possibility of good postoperative follow-up are
required before the CWU technique is used.
In this study, no statistically significant difference in pure tone average thresholds
before and after surgery with either of the techniques. Because patients with less
than 2 years follow-up were excluded from the study, there was a considerable decrease
in the number of individuals available for analysis, which hindered any robust analysis
of this variable. In the literature we found many studies that reported better audiometric
results when the CWU technique was used rather than the CWD technique[7]
[8]
[10]
[11]
[15]
[17]. However, other studies have reported no significant differences in hearing outcomes
in association with the two techniques[16].
Conclusion
The CWD technique and its various modifications results in better outcomes, especially
when it comes to surgery to control CCOM. Some precautions facilitate a satisfactory
functional outcome with better control of persistent otorrhea and greater certainty
as to the eradication of cholesteatoma compared to CWU mastoidectomy.
Table 1.
Disease control in patients with chronic otitis media with and without cholesteatoma
according to surgical technique.
|
Disease control
|
Total
|
RR (95% CI)
|
|
No
|
Yes
|
|
CCOM
|
|
Surgical Technique
|
|
|
|
0.25 (0.09–0.79)*
|
|
Canal wall-down
|
3 (15.0%)
|
17 (85.0%)
|
20
|
|
|
Canal wall-up
|
11 (57.9%)
|
8 (41.1%)
|
19
|
|
|
TOTAL
|
14 (35.9%)
|
25 (64.1%)
|
39
|
|
|
COMWC
|
|
Surgical Technique
|
|
|
|
2.05 (0.48–8.78)
|
|
Canal wall-dow
|
2 (25.0%)
|
6 (75.0%)
|
8
|
|
|
Canal wall-up
|
5 (12.2%)
|
36 (87.8%)
|
41
|
|
|
TOTAL
|
7 (14.3%)
|
42 (85.7%)
|
49
|
|
CCOM - Cholesteatomatous chronic otitis media; COMWC Chronic otitis media without
cholesteatoma; RR – Relative Risk; 95% CI - 95% confidence interval; p value from
the Chi-square test <0.05.
