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Ali et al. Plast Aesthet Res 2021;8:35 https://dx.doi.org/10.20517/2347-9264.2021.29 Page 7 of 15

[41]
operators to provide depth to the image . The exoscope can be used during dissection and/or during the
microvascular anastomosis.

There are several commercially available systems including the VITOM (Karl Storz, Tuttlingen, Germany),
ORBEYE (Olympus, Tokyo, Japan), Modus V (Synaptive Medical, Toronto, Canada), and KINEVO (Carl
Zeiss AG, Oberkochen, Germany) exoscope . The majority of the literature on exoscope use in head and
[42]
neck microvascular surgery utilizes the VITOM and ORBEYE system. There are differences between the
platforms. VITOM is essentially a high-resolution endoscope mounted on a pneumatic arm. The ORBEYE
and Modus V are free standing exoscopes - the ORBEYE offers 3D imaging while the Modus V provides a
2-dimentional (2D) image. Finally, the KINEVO is an operating microscope that can be converted into an
[42]
exoscope .

This technology has been more widely utilized in neurosurgery and less so in head and neck microvascular
surgery. Microvascular anastomosis using the 3D exoscope has been demonstrated in animal and laboratory
simulation studies [41,43] and, more recently, in clinical application. In 2012, Cheng et al. reported the use of
[44]
a 3D stereoscopic monitor system, in conjunction with the conventional microscope, in FTT microvascular
anastomosis. In 2017, Piatkowski et al. successfully performed breast FTT reconstruction using just the
[45]
3D exoscope. Since then, multiple studies have shown that 3D exoscopes can be safely and successfully used
in FTT microvascular anastomosis [46-49] . Furthermore, subjective advantages include favorable ergonomics,
excellent image quality, and ease of intraoperative use .
[50]

There are several advantages of the exoscope over the conventional operating microscopes. One of the
major reported advantages of the exoscopes is superior ergonomics. Chronic neck and back problems can
result from neck flexion to position appropriately to ocular lenses or surgical loupes. Users of the exoscope
have noted improved ergonomics and minimized need to adjust posture and position during use [43,50] .
Ultimately, improved surgeon ergonomics may reduce surgeon long term disability and increase career
[50]
longevity . The operating microscope also has a larger footprint occupying more space in the operating
room (OR) when compared to the generally more compact exoscope. The exoscope is also valuable for
teaching purposes. The exoscope allows surgical trainees and assistants to have the same visualization as the
senior surgeon. With the traditional operative microscopes, all other members of the surgical team, aside
from the senior surgeon, may have a 2D or inferior view. Studies have also noted that procedures on the
exoscope are easy to learn, and simulation studies have shown progressive improvement in performance
with repetition .
[43]

Disadvantages of the exoscope include the low depth of field and loss of resolution at higher
magnifications . There is debate on whether the image quality may be inferior to that of an operating
[45]
[45]
[41]
microscope , although other studies note superior clarity and sharpness with the exoscope . In addition,
there were surgeon complaints of headaches and nausea with the earlier versions of the 3D optics. This issue
[42]
seems to be much improved with newer versions of these exoscopes . Also, in several small studies,
microvascular anastomosis using the exoscope did take longer compared to that using the operative
microscope [44,45] . However, a recent pilot study by Ahmad et al. showed no difference in operative time. In
[50]
addition, there was no difference in ischemia time or microsurgical complications between the exoscope
and traditional microscope group.

Another necessary consideration is the cost of this technology. The estimated cost of the two most
commonly used exoscope systems in head and neck microvascular surgery, the VITOM and ORBEYE, is
$200,000 and $400,000, respectively . The cost accounts for multiple components including the exoscope
[42]