DISCUSSION
The major difference between Microscopy and Endoscopy is the surgical
view. Tarabichi et al reported that the view during microscopic surgery
is defined and limited by the narrow segment of the ear canal[2,3]. By contrast transcanal endoscope bypasses
the narrow segment of the ear canal and provides a wide view with 00
endoscopes. Furukawa et al [4], Lade et al[5] and Harugop et al [6]conducted studies to compare the microscopic and endoscopic views
tympanoplasty. They reported that in the microscopy groups, the tympanic
annulus was not completely visualized in 17%to20% of patients, thus
requiring canalplasty. However, in the endoscopy groups, the tympanic
annulus was completely visualized; hence, no patient required
canalplasty. Ayache [7] reported an even higher
rate of 73% of patients in whom anterior perforations of the tympanic
membrane were poorly visualized.
Comparing the success rates of microscopic and endoscopic tympanoplasty
is often the main concern. Success rates of 90% to 95% for microscopic
myringoplasty have been reported [8,9]. Similar
success rates of 80% to100% have also been reported for endoscopic
myringoplasty [10,11,12] Harugop et al and Lade et
al compared the success rates of microscopic and endoscopic
myringoplasty and reported no difference. The success rate in our study
was 86.6% and the AB reduction to <10 was in 63.3% and 10-20
DB reduction was 33.3% of patients. In 2008, Satyawati Mohindra et al.
did 49 cases of myringoplasty and 6 cases of Ossiculoplasties through
the transcanal route using rigid endoscopes. The success rate regarding
perforation closure was 91.5% and average air bone gap improvement was
22.24 dB in the myringoplasty groups [13]. Ahmed
ELGuindy (Tanta, Egypt) has evaluated the role of the rigid endoscope in
the management of 36 cases of dry central perforation of the tympanic
membrane. The graft uptake rate was 91.7% and air bone gap was closed
to less than 10 dB in 83.3% [14].
Endoscopic myringoplasty carries several advantages over the Microscopic
myringoplasty, most important it carries minimal scar which is
especially beneficial for the females. Shaving is not required in any of
these cases. Endoscopy has several disadvantages in ear surgery compared
with microscopy. First, the endoscope must be held in one hand, and only
the other hand is free to operate; this procedure is particularly
cumbersome when bleeding obscures the view of the operating field. In
addition, endoscopy provides a monocular view, which causes the loss of
depth perception compared with the binocular view provided through
microscopy. Moreover, endoscopic myringoplasty still requires more
training experience [ 2,3,11]. We partially
disagree with the above statement as most of the endoscopic surgeries
are done single handed so the required expertise is nothing special for
endoscopic myringoplasty. To us there are two most important requirement
others than the better hand control, one is a bloodless which is
achieved by sufficient canal infiltration with 1:2 Lakh Xylocaine with
Adrenalin and the other is dry temporalis fascia graft which makes the
manoeuvre of the graft easier. As far as the learning curve of the post
graduates is concerned its same as the other endoscopic procedure
requirement i.e. practice of diagnostic endoscopy in every patient in
the OPD. Temporal bone dissections to learn the methods of myringoplasty
before doing actual myringoplasty. In our study, endoscopes allowed us
close inspection and photo documentation of the tympanic membrane
perforation, the drum remnant, the eustachian tube orifice, the middle
ear mucosa and ossicular chain. The anatomical variations (tortuous or
stenotic ear canal, anterior meatal overhang etc. that hamper the view
of entire tympanic membrane during ear surgery were overcome by the use
of endoscopes. Moreover, the permeatal route avoided post aural
incision, resulting in less operative time and postoperative pain and
morbidity. Disadvantages of the endoscopic myringoplasty included the
one-handed surgical technique, a loss of depth perception, limited
magnification and the need for training [15]. One
major safety concerns with endoscopic ear surgery is excessive heat
dissipation. This was evident only when a xenon light source was used.
Adequate illumination of the middle ear space can be accomplished with
lower settings on the regular light source (because of the size of the
cavity) without the need of the xenon systems. Also, the tip of the
endoscope requires continuous cleaning with anti-fog solution, which
probably helps in cooling the endoscope
The endoscopic technique is the future of myringoplasty and
tympanoplasty. With results similar to the microscopic techniques and
the added advantages, the endoscope may become more popular than the
microscope. The endoscope holds the greatest promise in tympanoplasty
and cholesteatoma surgery and should increase the utilization of
transcanal over post-auricular procedures[16, 17].
CONCLUSION
Panoramic, wide angle, and magnified view provided by endoscope as well
as ability to easily negotiate through EAC and uninterrupted picture
overcomes most of the disadvantage of microscope. In our study success
rate was comparable between endoscopic and microscopic technique. In
terms of morbidity and postoperative recovery, endoscope produced better
results. Loss of depth perception and one-handed technique are some of
the disadvantage of endoscope that can be overcome with practice and use
of endo-holder. Thus, endoscopic myringoplasty can be a good alternative
of microscopic myringoplasty.