Initial Experience of 4K Three-Dimensional Digital Microscope for Lymphaticovenular Anastomosis

A digital microscope projecting the operative field onto a three-dimensional monitor has been developed and allows surgeons to perform “three-dimensional monitor–assisted microsurgery,” which is usually associated with distressful posture. A few articles in the neurosurgery field mentioned that the usability of digital microscopes was comparable to that of conventional optical microscopes.1 In the plastic surgery field, Ichikawa et al. and Piatkowski et al. reported the experience of the microvascular anastomosis with using the Vitom3D (Carl Storz, Tuttlingen, Germany),2,3 and Ahmed et al. also concluded that the usability of the ORBEYE (Olympus Corp., Tokyo, Japan) was not inferior to the optical microscope for microsurgery.4 However, there was a limitation for the usability in supermicrosurgery, defined as anastomosis of small vessels ranging from 0.3 to 0.8 mm because of the resolution under the large manipulation of the digital microscope. To support this, any articles regarding supermicrosurgery using digital microscopes have not been published. Herein, we report the initial experience of the lymphaticovenular anastomosis using a new type of digital microscope, the Hawk Sight (Mitaka, Tokyo, Japan). The lymphaticovenular anastomosis was approved by the Juntendo University Hospital Institutional Review Board in February of 2020 (approval number 19-101). In this study, lymphaticovenular anastomosis using the Hawk Sight was attempted in seven cases of cancer-related extremity lymphedema (upper limbs, n = 5; lower limbs, n = 2) and 13 anastomoses in total by two microsurgeons. The Hawk Sight was used during the dissection of lymphatic vessels and venules and microvascular anastomosis (Fig. 1). [See Video 1 (online), which demonstrates an overview of the lymphaticovenular anastomosis procedures with three-dimensional monitor–assisted microsurgery using the Hawk Sight. In this video, the principal surgeon is performing all procedures, using the 4K three-dimensional monitor.] All anastomoses between lymphatic vessels and venules were conducted in an end-to-end fashion. The average luminal diameter in the lymphatic vessel was 0.47 mm and the average anastomosis time was 31.5 minutes. The patency was confirmed by the lymph fluid flow from the lymphatic vessel to the vein by kneading and the indocyanine green angiography built into the Hawk Sight intraoperatively. (See Figure, Supplemental Digital Content 1, which shows an intraoperative view of indocyanine green angiography to check the patency of the anastomosis. The high-tech clarity enables surgeons to evaluate the patency with ease, https://links.lww.com/PRS/F393. See Video 2 (online), which demonstrates the monitor view of the anastomosis, the patency check, and the mode transition in indocyanine green angiography. The green color reflects the high density of the indocyanine green and helps assessment of the patency.] {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1.","caption":"This video demonstrates an overview of the lymphaticovenular anastomosis procedures with three-dimensional monitor–assisted microsurgery using the Hawk Sight. In this video, the principal surgeon is performing all procedures, using the 4K three-dimensional monitor.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_1l9advlg"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 2.","caption":"This video demonstrates the monitor view of the anastomosis, the patency check, and the mode transition in indocyanine green angiography. The green color reflects the high density of the indocyanine green and helps assessment of the patency.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_gjkele2d"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Fig. 1.: Overview of the lymphaticovenular anastomosis under the latest digital microscope, Hawk Sight. The focal length is so short that the camera head unit does not interfere with the principal operator’s straight view and the assistant’s view. The maximum manipulation is 110× under the minimum focal length (20 cm).To date, several digital microscopes are available in the operative field, and each digital microscope has the original features for outlook, focal length, zoom function, optics, and cost. When considering supermicrosurgery using digital microscopes, the important aspect is high resolution on the monitor under the maximum manipulation without disturbance of the straight view. The Hawk Sight has an incredibly wide and short focal length (200 to 1000 mm), coherent optical zoom system (8×), and 4K three-dimensional optics, and those technologies broke the limitations and allow microsurgeons to perform supermicrosurgery with “heads-up” style, which is better for surgeon ergonomics. In addition, its resolution in indocyanine green mode is so clear that it enables projection of the duct brightly and sharply and evaluation of the patency precisely. Meanwhile, the procedures’ time for dissection and anastomosis were prolonged compared to the conventional method using an optical microscope. In our opinion, because the main reason was the nearly short focal depth under the maximum manipulation, even surgeons familiar with the lymphaticovenular anastomosis procedure might feel this is troublesome when they start lymphaticovenular anastomosis by three-dimensional monitor–assisted microsurgery at the beginning. However, we consider this issue can be overcome with experience with this method. In conclusion, there seems to be room yet for improvement of digital microscopes, but the paradigm shift from optical microscopes to digital microscopes is coming to the field not only of microsurgery but also of supermicrosurgery, including lymphaticovenular anastomosis. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.