This study aimed to compare the short-term outcomes of laparoscopic-assisted colon cancer surgery in the Soloassist II-assisted (SA) group and in the human-assisted (HA) group.
A total of 76 patients with colon cancer who underwent laparoscopic-assisted right hemicolectomy and anterior resection performed by a single surgeon between January 2017 and May 2018 were recruited from the consecutively enrolled registry and retrospectively analyzed.
Of 76 patients, 43 underwent surgery with human assistance and 33 underwent surgery using the Soloassist II system. The clinicopathologic characteristics were not statistically different between the 2 groups. In both HA and SA groups, no statistical difference was observed between operation time (220.23 ± 47.83 minutes vs. 218.03 ± 38.22 minutes, P = 0.829), total number of harvested lymph nodes (20.42 ± 10.86 vs. 20.24 ± 8.21, P = 0.938), and other parameters of short-term outcomes (length of hospital stay, blood loss, open conversion, time to flatus, time to soft diet, and complication events). Subgroup analyses did not show statistical differences.
Soloassist II can reduce the participation of a human assistant during surgery and is not inferior to human assistance in laparoscopic-assisted colon cancer surgery. Thus, it is a feasible instrument in laparoscopic-assisted colon cancer surgery that can provide positive short-term outcomes.
Laparoscopic techniques in general surgery began with appendectomy, introduced by Semm in 1980 [
The da Vinci robotic surgical system (Intuitive Surgical Inc., Sunnyvale, CA, USA) was recently developed, and several institutions have reported their results. Despite some advantages, the high cost of the procedure has remained a problem [
An endoscope system is essential in laparoscopic-assisted surgery, and most endoscopes are held by a human assistant. However, as operation time increases, assistants may experience fatigue and capture unstable images due to tremor. Endoscope holder systems were developed to solve these problems and capture precise images. Initially, these were passive endoscope holders that attach to an endoscope [
The Soloassist II system (AKTORmed, Barbing, Germany), a robotic active endoscope holder system, is a joystick-guided endoscope remote control system [
A total of 76 patients with colon cancer who underwent laparoscopic-assisted right hemicolectomy (RHC) and anterior resection (AR) performed by a single surgeon at Wonkwang University Hospital between January 2017 and May 2018 were recruited from the consecutively enrolled registry and retrospectively analyzed.
Because our institution has used the Soloassist II system since October 2017, patients were divided into a HA group and a SA group (n = 43 and n = 33, respectively). All patients were diagnosed with colon cancer through pathologic biopsy and underwent elective surgery performed by the same surgeon. There were no inclusion criteria for applying the Soloassist II system. Conversion between HA laparoscopic surgery and SA laparoscopic surgery did not occur. This study was approved by the Institutional Review Board of Wonkwang University Hospital (WKUH 2018-07-007), and informed consent was waived.
The Soloassist II system is a robotic active endoscope holder that can be moved by a joystick. It consists of the main body unit, a power unit, a universal joint, an endoscope clamp, and a joystick. It can be attached to the side rail of a surgical bed, and the main body can be covered by a disposable drape. Other settings were comparable to those of conventional laparoscopic-assisted operations, except for the use of the Soloassist II system (
All surgical procedures were performed using the same method, endoscope, surgical bed, patient position, participant positions, and instrument positions, except for the use of the Soloassist II system in one group. All procedures were performed using standard laparoscopic-assisted surgery via conventional multiport methods. In cases of RHC, the endoscope trocar was inserted into the supra-umbilical area, and two operator ports were placed in the suprapubic area and left lower quadrant (LLQ), respectively. One assistant port was located in the epigastric area. The specimen was extracted via midline mini-laparotomy above the umbilicus. An extracorporeal ileocolic anastomosis was performed with intraluminal staples (ILS). For AR, the endoscope trocar was located on the left of the umbilicus, and 2 operator ports were placed in the right upper quadrant and right lower quadrant, respectively. One assistant port was inserted into the LLQ area. The sigmoid colon was extracted through mini-laparotomy of the LLQ. Intracorporeal colo-colic anastomosis was performed with ILS inserted through the anus. The HA group included 1 operator and 2 assistants, whereas the SA group included 1 operator and 1 assistant. The operator was an experienced colorectal surgeon who had experience performing laparoscopic-assisted surgery, including robot-assisted surgery (>400 cases). However, he was not experienced in using the Soloassist II system before this study.
The primary end point of the study was comparison of early surgical outcomes. Operation time (minutes), postoperative length of hospital stay (LOHS, days), estimated intraoperative blood loss (mL), and complication events were assessed. Operation time was measured in minutes from skin incision to skin suture. LOHS was measured in days from surgery to discharge. Blood loss was assessed by suction volume and gauze weight. Complication events included only grade II or higher complications of the Clavien-Dindo classification that occurred until the postoperative hospital stay. The total number of harvested lymph nodes (LNs) was evaluated based on pathologic biopsy results. Open conversion, time to flatus (days), and time to soft diet (days) were also assessed.
Patient demographic data were also analyzed, including age, sex, body mass index, American Society of Anesthesiologists physical status classification, history of previous abdominal operation, operation method, and cancer stage.
Comparisons of continuous variables between the 2 groups were made using independent t-test or Mann-Whitney U-test. The chi-square test and Fisher exact test were used to compare categorical variables. A 2-sided P-value < 0.05 was considered significant. All statistical analyses were performed using IBM SPSS Statistics ver. 24.0 (IBM Co., Armonk, NY, USA).
Of 76 patients (48 males and 28 females) included in the study, 43 underwent surgery with a human assistant and 33 had surgery with the Soloassist II system. The clinicopathologic characteristics of patients are shown in
LOHS was not statistically different between groups (HA: 9.93 ± 3.07 vs. SA: 10.24 ± 3.19, P = 0.667). No significant differences were identified for time to flatus (HA: 2.07 ± 0.46 vs. SA: 2.24 ± 0.50, P = 0.122) or time to soft diet (HA: 5.84 ± 2.10 vs. 5.97 ± 2.14, P = 0.788). Postoperative complications occurred in 2 patients from the HA group due to minor anastomosis leakage. In the SA group, 1 patient had postoperative ileus and the other had pleural effusion. All complication events were class II of the Clavien-Dindo classification. There were no significant differences in complications between the 2 groups (P = 1.000).
The characteristics of subgroups were not statistically different, even though they were reclassified according to the operative method (data not shown).
Laparoscopic endoscopes and instruments have developed gradually over the past 30 years and have various applications in the surgical field. In colon cancer surgery, laparoscopic-assisted surgery is not inferior to conventional open surgery, as shown by large-scale randomized trials. Laparoscopic-assisted surgery provides some advantages, such as shorter hospital stay, surgical wound minimization, and reduced pain [
In laparoscopic-assisted surgery, it is important to acquire precise images to ensure safety. High-resolution endoscopes and even 3-dimensional technology have recently evolved to enable safer and more sophisticated procedures [
Here, we compared the short-term outcomes of the HA and SA groups. Operation time and LOHS were not significantly different between the HA and SA groups (
In our experience, the Soloassist II system was easy to learn for inexperienced surgeons. It does not lead to prolonged operation time, increased LOHS, or additional complication events. These results are thought to be the same in all procedures except for those controlled by a joystick. In a previous study of cholecystectomy using the Soloassist, there was no defined learning curve or effect [
We could not compare long-term oncologic outcomes due to the short follow-up period. Instead, the total number of harvested LNs, which is associated with the prognosis of patients with colon cancer, was compared [
This study had several limitations. Although patient characteristics were similar, there were hidden confounders and biases due to the retrospective nature of this study. Next, this study had a small sample size (n = 76). Lastly, the long-term outcomes of the 2 groups were not compared because the follow-up period was short. Nevertheless, this was one of the few studies that evaluated the feasibility of using the Soloassist II in laparoscopic-assisted colon cancer surgery.
In conclusion, the use of Soloassist II can decrease the need for a human assistant during surgery and is not inferior to human assistants in laparoscopic-assisted colon cancer surgery. Therefore, Soloassist II is considered a feasible instrument in laparoscopic-assisted colon cancer surgery with positive short-term outcomes. However, the long-term oncologic outcomes of laparoscopic-assisted colon cancer surgery using Soloassist II should be evaluated in further studies.
No potential conflict of interest relevant to this article was reported.
Positioning of the Soloassist II system in laparoscopic-assisted right hemicolectomy (red arrow).
The surgeon can move the endoscope 360° using a joystick.
Clinicopathologic characteristics of patients
Variable | HA (n = 43) | SA (n = 33) | P-value |
---|---|---|---|
Sex | 0.301 |
||
Male | 25 (58.1) | 23 (69.7) | |
Female | 18 (41.9) | 10 (30.3) | |
Age (yr) | 68.09 ± 10.16 | 71.21 ± 10.48 | 0.195 |
Body mass index (kg/m2) | 24.11 ± 3.02 | 24.24 ± 3.79 | 0.866 |
ASA PS classification | 0.487 |
||
I | 2 (4.7) | 1 (3.0) | |
II | 37 (86.0) | 26 (78.8) | |
II | 4 (9.3) | 6 (18.2) | |
Previous abdominal operation | 7 (16.3) | 3 (9.1) | 0.499 |
Operation method | 0.272 |
||
Right hemicolectomy | 18 (41.9) | 18 (54.5) | |
Anterior resection | 25 (58.1) | 15 (45.5) | |
Cancer stage |
0.503 |
||
0 | 1 (2.3) | 1 (3.0) | |
1 | 11 (25.6) | 11 (33.3) | |
2 | 14 (32.6) | 5 (15.2) | |
3 | 15 (34.9) | 15 (45.5) | |
4 | 2 (4.7) | 1 (3.0) |
Values are presented as number (%) or mean ± standard deviation.
HA, human-assisted group; SA, Soloassist II-assisted group; ASA PS, American Society of Anesthesiologists physical status classification.
Independent t-test.
Chi-square test.
Fisher exact test.
Stage according to American Joint Committee on Cancer cancer stage manual, 8th edition.
Short-term outcomes in human-assisted and Soloassist II-assisted groups
Variable | HA (n = 43) | SA (n = 33) | P-value |
---|---|---|---|
Operation time (min) | 220.23 ± 47.83 | 218.03 ± 38.22 | 0.829 |
LOHS (day) | 9.93 ± 3.07 | 10.24 ± 3.19 | 0.667 |
Blood loss (mL) | 79.77 ± 48.53 | 68.79 ± 56.22 | 0.364 |
Total harvested lymph nodes | 20.42 ± 10.86 | 20.24 ± 8.21 | 0.938 |
Open conversion | 0 (0) | 0 (0) | |
Time to flatus (day) | 2.07 ± 0.46 | 2.24 ± 0.50 | 0.122 |
Time to soft diet (day) | 5.84 ± 2.10 | 5.97 ± 2.14 | 0.788 |
Complication events | 2 (4.7) | 2 (6.1) | 1.000 |
Values are presented as mean ± standard deviation or number (%).
HA, human-assisted group; SA, Soloassist II-assisted group; LOHS, length of hospital stay.
Independent t-test.
Fisher exact test.
Short-term outcomes according to operation method
Variable | Right hemicolectomy |
Anterior resection |
||||
---|---|---|---|---|---|---|
HA (n = 18) | SA (n = 18) | P-value |
HA (n = 25) | SA (n = 15) | P-value | |
Operation time (min) | 231.94 ± 61.55 | 221.94 ± 38.47 | 0.650 | 211.80 ± 33.82 | 213.33 ± 38.71 | 0.896 |
LOHS (day) | 10.72 ± 4.06 | 10.67 ± 4.03 | 0.584 | 9.36 ± 2.02 | 9.73 ± 1.75 | 0.305 |
Blood loss (mL) | 101.67 ± 48.42 | 87.22 ± 66.05 | 0.181 | 64.00 ± 42.92 | 46.67 ± 31.09 | 0.164 |
Total harvested lymph nodes | 24.33 ± 11.22 | 21.17 ± 8.36 | 0.323 | 17.60 ± 9.87 | 19.13 ± 8.17 | 0.616 |
Open conversion | 0 (0) | 0 (0) | 0 (0) | 0 (0) | ||
Time to flatus (day) | 2.00 ± 0.49 | 2.33 ± 0.59 | 0.203 | 2.12 ± 0.44 | 2.13 ± 0.35 | 0.978 |
Time to soft diet (day) | 6.06 ± 2.88 | 6.61 ± 2.66 | 0.161 | 5.68 ± 1.35 | 5.20 ± 0.86 | 0.292 |
Complication events | 2 (11.1) | 1 (5.6) | 1.000 |
0 (0) | 1 (6.7) | 0.375 |
Values are presented as mean ± standard deviation or number (%).
HA, human-assisted group; SA, Soloassist II-assisted group; LOHS, length of hospital stay.
Independent t-test or Mann-Whitney U-test.
Fisher exact test.