This single center single surgeon experience retrospective cohort study investigates the usage and benefits of 3D digital microscope in hepatic artery reconstruction during living donor liver transplant. Although operative techniques for hepatic transplant have matured enough to yield high success rates, we propose a few modifications that can be adopted to make vascular anastomosis in hepatic transplant easier for young surgeons.
The Use of Micro-forceps
Forceps are commonly used during operations and each surgical speciality has its own custom forceps that is designed to suit their operative approaches (Figure 1). The 15cm long forceps is a standard instrument in most general surgery operations, yet when used in hepatic artery anastomosis, it is not effective. As seen in Figure 2, the end of a 15cm long forceps, when held in the hand of surgeon during artery anastomosis, is against the operator’s palm and the operator’s fingers are pinched to have effective grip, which is tiresome for the hand and provides little lever working space. Furthermore, the surgeon’s hand motion is often limited by rib encasing the liver. To overcome this limitation, we use a 25cm, or 20cm, long micro-forceps for the procedure (Figure 1, right). As seen in the Figure 2, the extended length of this micro-forceps allows surgeons’ hand to work in a more relaxed grip with a working field that is wider and deeper. Leverage in longer forceps allow precise movement at forceps’ tip without much hand movement, which is essential for artery reconstruction. When both the primary surgeon and assistant surgeon use micro-forceps during the procedure (Figure 2, bottom), the assistant is able to provide assistance more precisely without blocking the surgeon’s working field and the anastomosis can proceeded smoothly and efficiently.
Tying Surgical Knots
Surgical residents were conventionally taught to hold the needle-holder with their dominant hand, usually the right-hand, and have the forceps in their non-dominant hand, usually the left-hand. Surgical knots were made by circling the forceps around the needle holder. However, during hepatic artery anastomosis, the rib encasing the liver will limit the surgeon’s field of exercise and since the since the working field is vertically beneath the hand, as seen in figure, surgical knots are often loose due to inadequate tie. Hence, we propose circling the needle-holder around the still forceps. The right-hand held needle-holder has more working space than the left-hand forceps, this allows more effective and firmer surgical knots to be made than the conventional method.
The Operation Setup: Operative microscope
Figure 3 shows the operation setup with conventional operative microscope (Control group). The main operator is on the left side and assistant operator on the right side of the microscope. To accommodate the microscope, operators often maintain a forward leaning, stiff neck and shrugged shoulder position. If the arm-board is used in some operations, operators may need to stand with twisted trunk position and slanted shoulder to gain visualization to the microscopic field. In addition, with only one objective lens and the microscope is usually set up to suit the primary surgeon, assistant surgeon often stands in awkward non-ergonomic positions.
The Operation Setup: Exoscope
Figure 4 shows the operative setup with the use of 3D digital microscope Mitaka Kestrel View II (Study group). As seen in Figure 5, both operators are standing in upright position with relaxed shoulder. A real time projection of the operation field that allows all bystanders, such as scrub nurse, anesthesiologist, surgical residents, to learn intraoperative techniques and follow the progress of the operation. In addition, looking at a projection screen is easier on the eyes for surgeons with presbyopia. Less physical discomfort with heighten surgeons’ concentration and willingness to teach and learn throughout this complicated surgery.
Benefits of Our Approach
Surgeons endure long and strenuous training years with high level of stress to perfect their surgical techniques to improve patients’ surgical outcome and prognosis. This pursuit of perfection comes at the cost of surgeons physical and mental health. Studies have found that 60-90% of all surgeons experience painful musculoskeletal conditions in their neck, back or shoulders.5,6,7 Microsurgeons experience these symptoms during or after microscope use.8 Our approach with using micro-forceps instead of standard forceps stabilizes the hand during vascular reconstruction with more precise movement and the modified suture tying method provides larger working field with firmer ties made. The use of exoscopes, such as 3D microscopy, can neutralize mal-posture and alleviate work-related injuries. However, surgeons cannot benefit themselves at the cost of jeopardizing patient’s health. Although Pafitanis et al. found that exoscopic microvascular anastomosis was more time consuming, our comparative analysis of hepatic artery reconstruction done via operational microscopy and via 3D digital microscopy showed no statistical nor clinical significance in operative outcome (Table 1). Both instruments have no hepatic artery size limit, and both have complete vessel patency rate. This non-inferiority is in concordance to previous study.8
Rosenblatt et al. analyze surgeons’ intraoperative posture and found three most common malposition that contributed musculoskeletal injuries: forward head position, improper should elevation and internal rotations, and pelvic girdle asymmetry. As in Figure 3, the forward leaning position, stiff neck position and shrugged shoulder causes fatigue in deltoid and trapezius muscles. Due to obstacles, surgeons need to maintain a twisted position to gain visualization of the operation field. This sustained twisting causes asymmetrical loading on back and leg muscles, leading to work-related musculoskeletal pain. Other risk factors that led to increased muscle activity and muscle fatigue include prolong static posture, hyperflexion of cervical spine and back-bent posture.6,11,12 Hence operating with a more neutral position should be reminded and reinforced among surgeons.
Modern digital exoscopes have its forte with surgeons. Its application ranges from open surgery to microsurgery and its ergonomics design, the projection of microscopic image onto a 3D monitor, allow surgeons to operate in a heads-up position, alleviating cervical musculoskeletal fatigue and work-related injuries. For surgeons with presbyopia, looking at a distant screen is more comfortable than a close-up image. Moreover, this real-time projection allows all active participants in the operation room to see the progress of the operation and allow bystanding surgical residents to learn intraoperative skills. 3D digital microscopy is an asset to surgeons in non-reconstructive specialties because of its similar operative method with laparoscopy and the switch from microscope to exoscope with good quality outcome can be achieved in relatively short practice time.13