Objectives:
Despite advancement in new equipment and surgical instruments, it is
only recently that three-dimensional (3D) endoscopes have been used in
endonasal and anterior skull base surgery. Previous publications have
shown the importance, advantages and limitations of three dimensional
endoscopy either in endonasal or skull base surgical
approaches.(1,
2) The endoscopes used in this study
incorporate dual ‘chip-on-the-tip’ technology in which two video chips
create two different digital images which are displayed onto a 3D
screen. Polarising glasses are worn to project a different image to each
eye.(3)
Extended endoscopic endonasal approaches are increasingly applied in the
management of various intracranial and cranial base pathologies. On one
end of the complexity spectrum, lie lesions such as pituitary adenomas
and encephaloceles of the cribriform plate, which can be more easily
approached through the endonasal
corridor.(4-6)
There are many advantages of endoscope however, it does not achieve the
binocular vision. The monocular endoscopes create a 2D image during the
operative view which lack the depth of perception, size orientation and
hand –eye
coordination.(7,
8) Human kinematic studies proved that
the longer movement times are required by monocular cues to estimate the
distance between variable surgical
landmarks.(9)
Many binocular cues are essential to gain the depth of perception like
convergence, stereopsis and vertical disparities which are the main
features of the three dimensional technology. To achieve stereopsis it
requires two meticulously different retinal images obtained from
different angles and directions and then the human cortex superimposes
these two images to give the stereopsis. Like the majority of
stereoscopic systems which give the 3D display of the surgical field by
production of minimally different images, then displayed separately to
each eye, so the generated two images are the concept of stereopsis
which named the dual channel and the shutter mechanism
technologies.(7)