Advantages of ET over MT
One of the primary advantages of the endoscope is the panoramic and wide
angle surgical view with magnification. In contrast, the microscope has
a straight-line view, which can be limited when encountering variations
of the EAC, such as a tortuous, stenotic ear canal and bony overhangs.
Therefore, surgeons may need to drill out or curette bony overhangs
during canaloplasty and canal wall curettage for complete visualization
and assessment of the TM and the status of ossicles. In the present
study, the rate of these required additional maneuvers was significantly
lower in ET than in MT since the endoscope can be approximated to the
surgical field, bypassing the narrowing parts of the EAC, and the angled
endoscope can be rotated to obtain all-round vision without the
requirement of these invasive maneuvers, thereby reducing morbidity and
operative time. In agreement with our findings, Tseng C-C et
al34, Lee S-Y et al35 and Pap I et
al36 reported a significantly lower canaloplasty rates
in ET than in MT.
In agreement with Lee S-Y et al35 and Pap I et
al36, another significant advantage regarding ET is
that the operative time for ET was significantly shorter than for MT.
The surgeon’s experience and
the learning curve generally have an impact on the operative time.
However, MT consumes more time due to frequent manipulation of the
patient’s head or repeated microscope adjustment for a better view,
using the post-auricular approach, or performing canaloplasty and
curettage. According to Hsu Y-C et al, the relatively short time
required for surgery and under anaesthesia results in the significantly
fewer medical resources expended on ET and decreased complications from
prolonged exposure to anaesthesia.37 In our
meta-analysis, the analysis for operative time data suffers from
significant heterogeneity and publication bias.
Characteristically, ET is advantageous concerning safety, minimal
invasiveness and the rate of complications. Because of a wide field of
view with magnification, ear surgeons have obtained minimally invasive
endoscope-assisted tympanoplasty accompanied by minimal complications.
In our meta-analysis, we focused particularly on the following
complications: the infection (wet ear), wound gap, visible scar, nausea
and vomiting. No significant difference was found between both
techniques with regard to infection and wound gap, but there was a
highly significant decrease in the rates of visible scar, nausea and
vomiting as well as the overall complications rate in favour of ET.
Postoperatively, the wet ear results from a severe middle ear
infection37 and the wound gap following suture removal
from early loose stitches27 rather than the procedure
itself. In the present study, a meta-analysis of cosmetic results
through the presence or absence of a visible scar revealed that the
endoscope was definitely preferred over the microscope. For ET, the
transcanal approach to the middle ear and smaller incision with minimum
tissue dissection for harvesting a graft lead to early wound healing and
less scarring on the graft donor site.16,18,26Besides, avoiding the post-auricular route reduces the incidence of
auricular displacement and asymmetry of the pinna yielding better
cosmetic outcomes.12,14,19,22 Similar to meta-analytic
results of visible scar, the rates of nausea and vomiting were
significantly lower after ET than after MT. Nausea and vomiting are
unpleasant events and are associated with patient discomfort and
dissatisfaction during postoperative recovery.38 These
two adverse events require administration of various treatment
modalities and consequently can expand recovery room time, increase
nursing care requests and the duration of hospital stay, and can further
increase total healthcare costs.39
In concordance with our results regarding complications, Lee S-Y et
al35 reported that wound problems of ET were
significantly lower than those of MT, but there was no significant
difference between ET and MT regarding wet ear.