Keywords
eustachian tube - bariatric surgery - weight loss
Introduction
The eustachian tube, an osteocartilaginous canal that communicates the middle ear
with the nasopharynx, is one of the most important structures responsible for the
functional balance of middle ear structures and is involved in mechanisms of protection,
aeration, and draining.[1]
[2] Tubal malfunction can cause extremely unpleasant symptoms, such as autophony, cacophony,
and the sensation of aural fullness.[1]
[2] These symptoms might be unveiled by several clinical conditions, including the acute
loss of weight after bariatric surgery.[3]
Bariatric surgery is already accepted as a treatment for morbid obesity and is becoming
increasingly widespread among these patients. Morbid obesity is a multifactorial chronic
disease and is genetically related to an excessive overstock of body fat. It is intimately
related to medical, psychological, physical, and economic comorbidities.[4] The obesity prevalence is rising among the world population, as is the number of
surgeries.[5] A 2009 Brazilian survey detected 14% obesity rate in Brazilian women, and in 4%
of those, morbid obesity. Among men, 11% were obese and 2% morbidly obese.[5]
Tube dysfunction after bariatric surgery might originate from the lack of fat tissue
that involves and supports the eustachian tube. The abrupt decrease of adipocytes
in this region caused by the acute loss of weight might lead to a failure of tubal
support and to a relaxation in this covering tissue, ultimately leading to eustachian
tube dysfunction symptoms. Although symptoms of auditory alterations related to tube
dysfunction are relatively frequent in these patients, only a few studies have investigated
this relationship.
This study aims to evaluate the occurrence of signs and symptoms related to eustachian
tube dysfunction in obese patients after bariatric surgery.
Methods
This prospective cohort study was conducted with adult patients (≥18 years) with body
mass index (BMI) > 40 or > 35 and presenting comorbidities related to their weight.
All patients underwent bariatric surgery by production of gastric bypass (Fobi-Capella
technique) at the same hospital, by the same surgeon. The hospital nutrition team
in the postoperative follow-up evaluated all patients.
The institution's ethics committee approved this project and the data were collected
between March and September 2011.
Prior to surgery, all patients had a hearing evaluation (otoscopy, tonal and vocal
audiometry, and impedanceometry) and a standardized hearing questionnaire. There was
no abnormality in those evaluations. Patients with disease or a history of ear surgery
were excluded.
The questionnaire included questions about gender, age, current BMI, and symptoms
related to tube dysfunction (aural fullness, sensation of water in ears, hearing own
voice (echo), hearing crackles, tinnitus, hearing own breath, hearing own heartbeat).
Three to four months (first postoperative evaluation) and 5 to 6 months (second postoperative
evaluation) after the surgery, all patients were reevaluated with the same questionnaire.
Patients presenting with tubal dysfunction symptoms underwent a new hearing evaluation
(otoscopy, tonal and vocal audiometry, and tympanometry).
Results
Twenty-one patients were selected for the study, but only 19 were included. Two were
lost during follow-up. Thirteen (68.4%) were female and six (31.6%) were male. The
age average and the overall median of BMI are shown at the [Table 1]. No patients reported abnormal auditory symptoms before the bariatric surgery or
had history of ear disease or surgery.
Table 1
Patient demographics
|
Age (y)
|
Preoperative BMI
|
Postoperative visit 1 BMI
|
Postoperative visit 2 BMI
|
|
|
Sex
|
Average
|
Standard deviation
|
Average
|
Standard deviation
|
Average
|
Standard deviation
|
Average
|
Standard deviation
|
n
|
|
Male
|
38.83
|
13.70
|
44.58
|
4.77
|
33.61
|
3.63
|
29.77
|
2.48
|
6
|
|
Female
|
39.38
|
10.65
|
40.35
|
3.15
|
31.04
|
3.31
|
27.84
|
2.85
|
13
|
|
Total
|
39.21
|
11.30
|
41.68
|
4.13
|
31.85
|
3.53
|
28.45
|
2.83
|
19
|
Abbreviation: BMI, body mass index.
Three to four months after surgery (first postoperative evaluation), average weight
loss among all patients was 31.57 kg. Among women this average was 24.53 kg and among
men, 32.25 kg. After 5 to 6 months (second postoperative evaluation), the average
loss of weight was 36.47 kg. Among women this average was 33.15 kg and among men,
43.66 kg. The values of BMI before surgery and at the first and second postoperative
evaluation are shown in [Table 1].
The prevalence of tube dysfunction in the preoperative period was 0%. In the postoperative
evaluations, 5 (26.3%) patients presented symptoms related to tube dysfunction at
the first evaluation, and 9 (47.3%) presented symptoms at the second evaluation. Average
onset of symptoms was 2.33 weeks (range: 1 to 20 weeks). The distribution of the most
frequent symptoms can be seen in [Fig. 1].
Fig. 1 Distribution of symptoms in postoperative visit 1 (3 to 4 months) and visit 2 (5
to 6 months), and number of patients who cited those symptoms.
Despite the frequency and intensity of the auditory complaints, no changes were detected
after surgery with otoscopy and tympanometry.
Discussion
In an adult, the eustachian tube is usually ∼35 to 38 mm in length, presenting 26 mm
of fibrocartilaginous tissue. The lumen of this part of the tube is practically virtual,
remaining closed due to its elastic properties, only opening at yawning, swallowing,
or sneezing.[1]
[2]
[6] The real mechanism of the tube's opening is still controversial, but it is believed
that the tensor veli palatini, elevator veli palatine, and salpingopharyngeus muscles
are involved.[6]
Factors involved in tubal dysfunction include loss of adipocyte tissue around the
tube (Ostmann's fat), abnormal activity of peritubal muscles (tensor and elevator
veli palatine and salpingopharyngeus), and inability of pterygoid venous plexus to
assist the closure of the tube.[3]
Our study aimed to evaluate the relationship between acute loss of weight after bariatric
surgery and the occurrence of tubal dysfunction symptoms. As the bariatric surgery
is already ordained as treatment for morbid obesity and is becoming more and more
widespread among this population, the impact in tubal function could be relevant.
All patients of this study had formal indications for surgery. Patients who lost weight
faster were those with tubal dysfunction symptoms. Although the peak of weight loss
occurred between 5 and 6 months, some auditory symptoms appeared 1 week after surgery,
worsening with the progression of the loss of weight. It is interesting to note that
despite the symptoms of tubal dysfunction, such as autophony, no patient presented
alterations in audiometry and tympanometry. Unfortunately, objective diagnosis of
tubal dysfunction is still difficult, as the symptoms are not always present at the
examination time (e.g. tympanometry). The diagnosis remains based on the patient's
history and clinical symptoms.[2]
[3]
We believe that tubal dysfunction symptoms in our patients were related to the acute
loss of adipocyte tissue that surrounds the cartilage part of the eustachian tube
(Ostmann's fat). Other authors reported the same results in similar conditions of
weight loss such as in restrictive alimentary diet, the puerperium period, and anorexia.[1]
[2]
[3]
[7]
Letti, in 1977, evaluated eight patients with complaints of patent tube; they all
had a restrictive diet, with average weight loss of 15 kg in 45 to 65 days. The author
observed that patients who submitted to very a restrictive diet with significant loss
of weight or those with a severe disease, with poor general condition and nutrition,
might present more permeability of the tube, predisposing its patency due to the loss
of the peritubal adipocyte tissue.[7]
These studies strongly suggest that an acute and significant loss of weight can make
these patients more susceptible to develop tubal dysfunction than the general population.
More studies are necessary to evaluate the relationship between loss of weight and
occurrence of these symptoms and their intensity. A long-term follow-up with specific
tests for tubal dysfunction would be useful to analyze the persistence and/or improvement
of these symptoms and their relevance to the quality of life of these patients.
Conclusions
This study suggests that bariatric surgery can cause symptoms of eustachian tube dysfunction,
probably due to rapid weight loss and the consequent loss of peritubular fat.
