Standardize the Surgical Technique and Clarify the Relevant Anatomic Concept for Complete Mobilization of Colonic Splenic Flexure Using da Vinci Xi® Robotic System

Predictors of difficulty in robotic splenic flexure mobilization during rectal cancer surgery

PURPOSE

In surgery for rectal cancer, splenic flexure mobilization is sometimes necessary to ensure a tension-free colorectal anastomosis with adequate blood supply. Splenic flexure mobilization is regarded as a challenging and risky maneuver, but there are no clear indicators of its difficulty in rectal cancer surgery. This study evaluated the impact of clinical and anatomical factors, including splenic flexure height measured qualitatively on the basis of vertebral level using computed tomography, on the difficulty of splenic flexure mobilization during rectal cancer surgery.

METHODS

The enrolled patients underwent robotic splenic flexure mobilization during rectal surgery for primary rectal cancer at Shizuoka Cancer Center in Japan between December 2011 and March 2022. All patients were scheduled to undergo splenic flexure mobilization preoperatively, and all procedures were carried out following a standardized approach. Linear regression analysis was conducted to determine the clinical and anatomical factors significantly influencing the operative time of the abdominal phase, which is defined as the duration from lymph node dissection around the inferior mesenteric artery to the mobilization of the sigmoid and descending colon, including the splenic flexure.

RESULTS

The median operative time for the abdominal phase was 88 min (range, 39-179 min). Univariate analysis revealed that the following variables were significantly correlated with a prolonged abdominal phase: higher body mass index, larger visceral fat area, and higher splenic flexure. In a multiple linear regression analysis, only higher splenic flexure remained significantly associated with a longer abdominal phase (p < 0.01).

CONCLUSIONS

Splenic flexure height measured on the basis of vertebral level using computed tomography may be useful for predicting the difficulty of robotic splenic flexure mobilization in surgery for rectal cancer.

Gaining Mesenteric Length following Colorectal Resection: Essential Maneuvers to Avoid Anastomotic Tension

A surgeon must possess the knowledge and technical skill to obtain length following a left-sided colorectal resection to perform a tension free anastomosis. The distal target organ - either rectum or anus - is fixed in location, and therefore requires surgeons to acquire mastery of proximal mobilization of the colonic conduit. Generally, splenic flexure mobilization (SFM) provides adequate length. Surgeons benefit from clearer understanding of the multiple steps involved in SFM as a result of improved visualization and demonstration of the relevant anatomy - adjacent organs and the attachments, embryologic planes, and mesenteric structures. Much may be attributed to laparoscopic and robotic platforms which provided improved exposure and as a result, development or refinement of novel approaches for SFM with potential advantages. Complete mobilization draws upon the sum or combination of the varied approaches to accomplish the goal. However, in the situation where extended resection is necessary or in the case of re-operative surgery sacrificing either more proximal or distal large intestine often occurs, the transverse colon or even the ascending colon represents the proximal conduit for anastomosis. This challenging situation requires familiarity with special maneuvers to achieve colorectal or coloanal anastomosis using these more proximal conduits. In such instances, operative techniques such as either ileal mesenteric window with retroileal anastomosis or de-rotation of the right colon (Deloyer's procedure) enable the intestinal surgeon to construct such anastomoses and thereby avoid stoma creation or loss of additional large intestine.

An improved path planning algorithm based on artificial potential field and primal-dual neural network for surgical robot

Safety and accuracy are essential for path planning in a surgical navigation system. In this paper, an improved path planning algorithm is proposed to increase the autonomous level of spine surgery robots for higher safety and accuracy. Firstly, the dynamic gravitational constant and piecewise repulsion function are adopted to improve the traditional Artificial Potential Field algorithm to solve the common issues of path planning, including local minimum, unable to reach the target near obstacles. To better control the pose of the end-effector in an operation space, the positions of the two endpoints of the end-effector are further constrained. Secondly, an improved Primal-Dual Neural Network with multiple constraints is proposed to minimize the joint angular velocity norm. The multiple constraints are formulated according to the planned path, the obstacle avoidance of the robot and the joint limits. Moreover, a real-time planned velocity scheme is applied to prevent the accumulation of position errors. The simulation results of the pedicle screw implantation demonstrate that the robot can find the collision-free trajectory and arrive at the target position in various complicated situations. More specifically, the error between two endpoints of the end-effector and the target pose is below 0.1 mm in reaching the surgical tool pose, while the maximum position error is around 0.05 mm when performing the planned path. Moreover, two experiments are conducted in the real-world to verify the proposed algorithm is effective in practice.

Surgical Outcomes of Robotic Resection for Sigmoid and Rectal Cancer: Analysis of 109 Patients From a Single Center in China

Background: Robotic colorectal surgery has been increasingly performed in recent years. The safety and feasibility of its application has also been demonstrated worldwide.However, limited studies have presented clinical data for patients with colorectal cancer (CRC) receiving robotic surgery in China. The aim of this study is to present short-term clinical outcomes of robotic surgery and further confirm its safety and feasibility in Chinese CRC patients.

Methods: The clinical data of 109 consecutive CRC patients who received robotic surgery at Sun Yat-sen University Cancer Center between June 2016 and May 2019 were retrospectively reviewed. Patient characteristics,tumor traits, treatment details, complications, pathological details, and survival status were evaluated.

Results: Among the 109 patients, 35 (32.1%) had sigmoid cancer, and 74 (67.9%) had rectal cancer. Thirty-seven (33.9%) patients underwent neoadjuvant chemoradiotherapy. Ten (9.2%) patients underwent sigmoidectomy, 38 (34.9%) underwent high anterior resection (HAR), 45 (41.3%) underwent low anterior resection (LAR), and 16 (14.7%) underwent abdominoperineal resection (APR). The median surgical procedure time was 270 min (range 120–465 min). Pathologically complete resection was achieved in all patients. There was no postoperative mortality. Complications occurred in 11 (10.1%) patients, including 3 (2.8%) anastomotic leakage, 1 (0.9%) anastomotic bleeding, 1 (0.9%) pelvic hemorrhage, 4 (3.7%) intestinal obstruction, 2 (1.8%) chylous leakage, and 1 (0.9%) delayed wound union. At a median follow-up of 17 months (range 1–37 months), 1 (0.9%) patient developed local recurrence and 5 (4.6%) developed distant metastasis, with one death due to disease progression.

Conclusions: Our results suggest that robotic surgery is technically feasible and safe for Chinese CRC patients, especially for rectal cancer patients who received neoadjuvant treatment. A robotic laparoscope with large magnification showed a clear surgical space for pelvic autonomic nerve preservation in cases of mesorectal edema.

Optimizing outcomes of colorectal cancer surgery with robotic platforms

Advanced robotic technology makes it easier to perform total mesorectal excision procedures in the narrow pelvis for rectal cancer while maintaining the advantages of minimally invasive surgery. Robotic surgery for rectal cancer leads to lower conversion rates and faster recovery of urogenital function than conventional laparoscopic surgery. However, longer operative time and high cost are major weaknesses of robotic surgery. To date, most other short-term surgical outcomes, pathologic outcomes, and long-term oncologic outcomes of robotic surgery have not shown significant advantages over laparoscopic surgery. However, robotic surgery is still a valid and highly anticipated surgical approach for rectal cancer because it greatly reduces the surgeon's workload and learning curve. There are also advantages when robotic techniques are applied to technically demanding procedures such as lateral pelvic lymph node dissection or intersphincteric resection. The introduction of new surgical robot systems, including the da Vinci® SP system, is expected to expand the applications of robotic surgery and provide new advantages.

The art of robotic colonic resection: a review of progress in the past 5 years

Surgery is developing in the direction of minimal invasiveness, and robotic surgery is becoming increasingly adopted in colonic resection procedures. The ergonomic improvements of robot promote surgical performance, reduce workload for surgeons and benefit patients. Compared with laparoscopy-assisted colon surgery, the robotic approach has the advantages of shorter length of hospital stay, lower rate of conversion to open surgery, and lower rate of intraoperative complications for short-term outcomes. Synchronous robotic liver resection with colon cancer is feasible. The introduction of the da Vinci Xi System (Intuitive Surgical, Inc., Sunnyvale, CA, USA) has introduced more flexibility to colonic operations. Optimization of the suprapubic surgical approach may shorten the length of hospital stay for patients who undergo robotic colonic resection. Single-port robotic colectomy reduces the number of robotic ports for better looking and faster recovery. Intestinal anastomosis methods using totally robotic surgery result in shorter time to bowel function recovery and tolerance to a solid diet, although the operative time is longer. Indocyanine green is used as a tracer to assess blood supplementation in the anastomosis and marks lymph nodes during operation. The introduction of new surgical robots from multiple manufacturers is bound to change the landscape of robotic surgery and yield high-quality surgical outcomes. The present article reviews recent advances in robotic colonic resection over the past five years.