Three-Dimensional Video Microscopy: Potential for Improved Ergonomics without Increased Operative Time?

Abstract

Three-dimensional (3D) video exoscopes are high-magnification stereo cameras that project onto monitors mounted in the operating room, viewable from different angles. Outside of plastic surgery, exoscopes have been shown to successfully improve the ergonomics of microsurgery, though sometimes with prolonged operating times. We compare a single surgeon's early experience performing free flap procedures from 2020 to 2021 using either a binocular microscope or a 3D video exoscope. Ten procedures were performed with the standard operating microscope and 8 procedures with the 3D exoscope. The microsurgeon, having minimal prior experience using an exoscope, reported less neck discomfort following the free flap procedures performed with the exoscope compared with the binocular surgical microscope. Total average operating time was comparable between the standard surgical microscope and the 3D exoscope (13.7 vs. 13.4 hours, p  = 0.34). Our early experience using a 3D exoscope in place of a standard optical microscope demonstrated that the exoscope shows promise, offering an ergonomic alternative during microvascular reconstruction without increasing overall operating times. Future studies will compare free flap ischemia time between cases performed using the exoscope and the conventional binocular microscope. Medical Subject Headings authorized following words: free tissue flaps; operating rooms; ergonomics; microsurgery.

Since the birth of microvascular surgery in the early 1960s, many improvements have emerged to aid microvascular anastomosis. Typically, an operating microscope or surgical loupes are used to establish a magnified view of the surgical field. 1 However, the use of surgical microscopes aggravates the ergonomic stress that microsurgeons frequently experience due to sustained static postures and hyperflexion of the cervical spine for prolonged periods of time. 2 3 4 The use of binocular surgical microscopes for 3 hours or more per week has been associated with an increased incidence of musculoskeletal complaints due, in part, to prolonged neck flexion. 5 A survey of plastic surgeons in North America reported that almost 80% of plastic surgeons experience musculoskeletal symptoms, most commonly neck and lower back pain. 6

Newer biomedical devices such as three-dimensional (3D) video microscopes (also known as “exoscopes”) have emerged as an alternative to the classic operating microscope. These devices substitute the optics of a standard microscope with a stereo video camera. The resulting image is projected onto a high-resolution monitor that can be viewed using polarized glasses to provide depth perception. The 3D exoscope was first introduced in the field of neurosurgery as an alternative to the standard operating microscope. Oertel and Burkhardt described the application of the VITOM-3D exoscope in cranial and spinal procedures in 2017. The authors noted comparable image quality to the standard operating microscope and an excellent comfort level for all procedures performed with the exoscope. 7 Several other studies have demonstrated that the 3D-exoscope may prove superior to the operating microscope in terms of depth of focus, image quality, and ergonomics. 1 8 9 10 11

Despite the benefits associated with the use of the 3D exoscope, prolonged operative times have been described in the literature. 9 10 12 13 We aimed to compare the benefits, techniques, and operating (ischemia) times for each type of microscope in performing microvascular reconstructive procedures. We report on a single surgeon's experience performing free flap procedures from 2020 to 2021 using both a binocular microscope and the Modus V (Synaptive Medical Inc. 2017, 555 Richmond Street West, Suite 800, Toronto, ON, M5V 3B1) 3D exoscope. This exoscope offers a field of view of 6.5 to 207.9 mm and can be configured in a way that optimizes the operating room layout ( Figs. 1 and 2 ) .

Fig. 1.

Operating room setup using the three-dimensional (3D) exoscope in reconstructive microsurgery.

Fig. 2.

The principal surgeon and assistant surgeon are each standing in a position of comfort, facing a three-dimensional monitor that is behind the other surgeon. The video monitors are mirrored and positioned to provide an unobstructed view, enabling all participants wearing special polarized eyewear to experience a magnified view of the surgical field.

We describe the first 9 free flap procedures performed with the exoscope and 11 consecutive free flap procedures performed with the standard binocular surgical microscope during the same time frame. Ischemia times and differences in technique were compared between similar procedures performed with each type of microscope ( Fig. 3 ).

Fig. 3.

Scrub technician's view. The monitor and motion sensor are both adjustable to promote neutral posture, limit neck flexion, and optimize surgical ergonomics.

Twenty patients underwent free flap reconstructions between 2020 and 2021, including the first 9 performed with a 3D exoscope. The total ischemia time was comparable for free flaps performed with the exoscope and the standard binocular microscope (152 minutes vs. 110 minutes, respectively; p  = 0.054). The type of microscope was not a significant predictor of ischemia time for radial forearm free flap phalloplasty (exoscope: 195 minutes vs. standard microscope: 154 minutes; p  = 0.117). Similarly, ischemia time was comparable for both unilateral and bilateral deep inferior epigastric artery perforator (DIEP) breast reconstruction (exoscope: 83 minutes per breast vs. standard microscope: 94 minutes; p  = 0.29; Tables 1 and 2 ) .

Table 1. Cases performed with the 3D exoscope.

Case	Procedure	Nerve coaptations	Arterial anastomoses	Venous anastomoses	Ischemia time (min)
1	RFFF PUP	2	1	2	225
2	RFFF PUP	2	1	2	169
3	RFFF PUP	2	1	2	221
4	ALT PUP	1	1	1	143
5	RFFF PUP	2	1	2	218
6	Unilateral DIEP		2	2	98
7	Unilateral DIEP		2	2	99
8	Unilateral DIEP		2	2	52
9	RFFF PUP	2	1	2	143

Abbreviations: 3D, three dimensional; ALT PUP, anterolateral thigh flap phallourethroplasty; DIEP, deep inferior epigastric perforator flap; RFFF PUP, radial forearm free flap phallourethroplasty.

Table 2. Cases performed with a standard operating microscope.

Case	Procedure	Nerve coaptations	Arterial anastomoses	Venous anastomoses	Ischemia time (min)
1	RFFF PUP	2	1	2	106
2	Unilateral DIEP	2	1	2	84
3	Unilateral DIEP		2	2	157
4	Unilateral DIEP		2	2	75
5	Unilateral DIEP		2	2	105
6	Unilateral DIEP		2	2	57
7	Unilateral DIEP		2	2	93
8	Unilateral DIEP		2	2	112
9	Unilateral DIEP		2	2	69
10	RFFF PUP	2	1	2	171
11	RFFF PUP	2	1	2	185

Abbreviations: ALT PUP, anterolateral thigh flap phallourethroplasty; DIEP, deep inferior epigastric perforator flap; RFFF PUP, radial forearm free flap phallourethroplasty.

Our experience using a 3D exoscope in place of a standard optical microscope demonstrates that the exoscope shows promise, offering an ergonomic alternative during microvascular reconstruction without significantly increasing ischemia times. 3D exoscopes have recently been adopted as an alternative to the traditional operating microscope and surgical loupes due to several advantages. The emergence of a 3D imaging system with 4K-resolution has been reported as a notable benefit, as it allows for enhanced visualization of the surgical field with adequate depth perception. 14 15 Another reported advantage is the notable reduction in thermal injury to tissues during surgery as the LED light source of the 3D exoscope radiates much less heat than the light source of standard microscopes. 16 17 Improved posture and decreased musculoskeletal strain have also been described by surgeons using the 3D exoscope. 10 14 This is particularly important in microsurgery, which requires a sustained downward gaze and static posture in the neck and shoulders. 18 Additionally, the 3D exoscope offers all participants in the operating room a 3D view of the operation, as long as they have the appropriate eyewear. Though standard operating microscopes may also project a view of the surgical field on monitors mounted in the operating room, the image is flat and does not provide the viewer perception of depth. 19 This 3D view of the surgical field is helpful from a teaching standpoint, as all viewers, including trainees and observers, experience the same image.

Although the exoscope offers excellent 3D vision and stereopsis, there have been reports of surgeons developing headaches and dizziness from use of the 3D glasses during the surgical procedures. 19 3D exoscopes have also been linked to prolonged operative times in comparison to the standard microscope. 10 13 14 15 This may be attributed to a learning curve since most surgeons are not familiar with this new tool and the need to develop indirect vision skills to maneuver. 16 Piatkowski et al describe their experience using a 3D exoscope and a standard operating microscope for autologous breast reconstruction. Though complication profiles were comparable between the two types of microscopes, microvascular anastomoses took longer to complete with the 3D exoscope. 20 This contrasts with our experience using the exoscope for DIEP flaps where ischemia times averaged 10 minutes less (this did not reach significance). Additionally, the cost of a 3D exoscope typically ranges between $250,000 and $1,500,000, which is similar to the cost of a high-end conventional microscope but may be a limiting factor for some healthcare systems. 16

There appears to be a growing awareness and urgency surrounding musculoskeletal injury in surgery. Our preliminary experience using an exoscope sheds light on an important recently introduced technology that may be adopted into clinical practice to improve the ergonomics of microsurgery. Microvascular plastic surgeons have yet to widely adopt the 3D exoscope, but we demonstrate its potential utility while allaying fears that it is difficult to learn and adapt to microsurgical practice.

Ultimately, adoption of this technology, along with other ergonomic improvements, may better protect the health and career longevity of the physician workforce.

Funding Statement

Funding The authors have no commercial associations or financial disclosures to declare in relation to the content presented in this manuscript. No funding was received for this work.