Discussion
Endoscopic sinus surgery is considered the gold standard for the
management of most sinus pathology. Improvements and updates in image
quality and angled scopes have resulted in advances in endoscopic sinus
surgery (ESS) with the expansion of use of the endoscopic approach in
skull base surgical
interventions.(10)
The three dimensional (3D) endoscopes have been utilized for endonasal
surgery, and recent publications have shown the advantages and a number
of limitations in using 3D endoscopes in endonasal sinus surgery or
skull base surgical
approaches.(2) In these
reports, 3D images were reconstructed from multiple 2D images obtained
using special lenses that imitate the compound eye of bees, from various
angles.(11) This is a
different technology to the 3D HD storz endoscopes that were used in
this study.
In our clinical study, the mean operative time in the 2D group was
significantly higher than the 3D group. This is also shown by
Castelnuovo et al., (2012), while studying the utilization of the 3D
endoscope in resection of anterior skull base malignancy, they found a
statistically significant reduction of both operative time and error
rates by using the new stereoscopic
endoscope(12), which
require the passive polarizing three dimensional
display(13) compared to
two dimensional endoscope. Also they recorded
low(14) or absent
surgeon discomforts with the novel stereoscopic
systems.(15) Moreover
Barkhoudarian et al., reported that there is a strong evidence for 3D
allowing a 30-minute reduction in pituitary adenoma resection operating
time.(16) A shorter
operative time decreases the risk of postoperative complications in
endoscopic pituitary
surgery.(17)
In our study, the frequency of using the surgical navigation system
showed that there was a highly significant increase in frequency of
navigation system use in the 2D group more than the 3D group. There are
no similar studies in the literature to compare to our study but these
results are in keeping with the hypothesis that 3D endoscopy gives
improved depth of perception hence a reduction in the need to use
navigation to confirm anatomy.
In our 2D group there was no surgeon discomfort during all operative
cases while 3 operative cases in the 3D group resulted in the surgeon
reporting discomfort (headache/migraine); there was no significant
difference between the two studied groups. Other authors in clinical and
experimental studies reported similar results. Moreover a small number
of surgeons in multiple studies recorded user side effects and
discomforts like dizziness, eye strain, fatigue, migraine and headaches
in 3D endoscope
users.(18)
Minimally invasive surgery is the standard of patient care in many
institutions (19).
However, incidents of increased complication rates among inexperienced
surgeons have been reported and a detailed study of these claims
demonstrates that the surgical learning curve plays a vital role in the
rate of complications.(20)
Regarding intraoperative complications, the incidence of complication in
our 2D group was higher than 3D group, however it was statistically not
significant. The most common complication in our 2D group was cavernous
bleeding in 11 cases (42.3%) followed by C.S.F leak in 6 patients
(23.1%), while in 3D group there were 7 cases of C.S.F leak (26.9%)
followed by cavernous bleeding in 5 patients (19.2%).
For endoscopic pituitary surgery, the Southern Surgeons club noted that
90% of complications happened in the first 30 patients of the learning
curve, with the initial risk being tenfold of that after 50
operations.(21) They
were using 2D endoscopy and a number of explanations were given
including: loss of depth perception (stereopsis), ergonomic difficulties
of using an endoscope, and issues with
training.(20,
21)
Regarding our cadaveric study, the mean dissection time for both sides
of the cadavers using 2D endoscope was 19.67±1.53 minutes while in using
3D endoscope was 21.33±4.93 minutes which was not statistically
significant (p > 0.05). It is possible that if we had
chosen a more complicated index longer operation to compare then we
might increase the likelihood of repeating the same results as seen in
the clinical study with 2D taking longer than 3D.
The cadaveric study describes only a qualitative comparison of various
approaches and anatomical landmarks using 3-dimensional endoscopy as a
new learning tool and technique. Future studies should focus on more
detailed quantitative comparisons of field exposure and surgical
limitations.