DISCUSSION
Adenoidectomy has been the hallmark treatment in children suffering from
otitis media with effusion since past many decades(1). There have been various expansion in research in
the field of adenoidectomy and its outcomes, but sparse literature is
available studying the outcome of adenoidectomy on middle ear functions.
There is a paucity of literature available in testing middle ear
functions post adenoidectomy and thus we conducted this study to
critically appraise the results comparing the middle ear functions post
conventional and endoscopic microdebrider assisted adenoidectomy.
Adenoid hypertrophy in children is the most common cause of eustachian
tube blockage leading to fluid collection in the middle ear i.e otitis
media with effusion leading to derangement of middle ear functions and
various modalities of treatment have been in use since time immemorial
in treating it.
In a recent Cochrane review by Van den Aardweg et al. [2] they
reported that there is a significant benefit of adenoidectomy in the
resolution of middle ear effusion in children with OME, but the benefit
to hearing is small and the effects on changes in the tympanic membrane
are unknown.
Coyle et al (3) also concluded in his study that adenoidectomy is a
useful procedure for correction of medically resistant chronic OME and
should be considered as the first line procedure when surgical treatment
is chosen.
However the dissatisfaction over the widely used conventional curettage
adenoidectomy since many years has prompted the use of endoscopic
assisted powered shaver adenoidectomy with microbebrider in recent
times.
Setliff and parsons introduced microdebrider use in nasal surgery in
1994. The unique design equipped with powered shaver, continuous
irrigation device and suction port makes this instrument superior in
clearing tissue from the field under direct vision with minimal
complications.
Stainslaw et al(4) found that tissue dissection was more complete and of
appropriate depth with a microdebrider as compared to the depth being
too shallow in conventional method leaving behind significant tissue
post procedure.
Various studies conducted by Murray et al. Rodigruez et al. Costantini
et al. proved that endoscopic assisted powered shaver adenoidectomy is
more effective in cleaning adenoid tissue under direct visualization;
thus requiring less operating time, causing less blood loss, and
providing more complete removal of the adenoid tissue and less
post-operative pain. ( 5, 6 )
By using endoscopic assisted adenoidectomy with a microdebrider, the
adenoid remnants along the superior portion of the nasopharynx, the
choanae and the peritubal region, can be clearly visualized easily and
thus removed completely. Moreover, the likelihood of damage to the
Eustachian tube and/or to the pharyngeal muscles is reduced, thereby
reducing the post-operative scarring. Hemorrhage can also be effectively
controlled by direct identification of the bleeding points (7, 8).
Tympanometry has been a novel approach in studying the function of
middle ear including middle ear pressures, volume and compliance. This
study also states the use of these modalities in testing middle ear
function. According to Renvall et al (9) stapedial reflex is considered
too sensitive to be used as a screening test in the diagnosis of OME
thus we excluded it from our criteria.
The patients included in our study showed a significant improvement in
hearing thresholds post endoscopic microdebrider assisted adenoidectomy
resulting in only 4 % patients with abnormal hearing threshold in
comparison to the conventional method being 24 % ( p value 0.004 ).
There was not much statistical difference seen in the peak compliance
comparing the two groups but however the peak middle pressures were
found to be significantly improved post surgery in children undergoing
endoscopic microdebrider assisted adenoidectomy compared to conventional
method .
The initial preoperative tympanograms of patients presenting showed B
and C type of curves which were found to have significantly improved
(normal A type) in children who underwent endoscopic microdebrider
assisted adenoidectomy in our study.
Similar studies have been conducted in evaluating the conversion rates
of tympanograms by Sarafoleanu et al. in 2010 which revealed a type-B
curve in 41% of cases, compared with type-A in 22% and type-C curve in
37% of cases. Re-evaluation performed after 4 weeks of surgery
(classical adenoidectomy) in their study also documented very good
relief of disease on subjective as well as objective evaluation (10).
Another study by Mori et al. in 1980 also observed a type-B tympanogram
in 50% of cases preoperatively with post-operative conversion to
type-A. (11)
Thus the clinical outcome and improvement in middle ear functions was
found to have improved drastically in the children who underwent
microdebrider assisted adenoidectomy as compared to the conventional
method .