The use of LS has occurred for more than 30 years since Delaitre et al. reported it in 1991[2] and Tulman et al. applied LS to pediatric surgery in 1993[3]. Compared with traditional surgery, LS had the advantages of less surgical trauma and faster postoperative recovery. It has been widely promoted in clinical practice and is currently the first choice for splenectomy. However, LS is still a laparoscopic surgery with high risk and difficulty, and it requires high surgical skills and a clinically experienced surgeon.
The da Vinci Robotic Surgery system is an upgraded intelligent laparoscopic system, which can greatly reduce the difficulty of complex operations in minimally invasive surgery and simplify complex operations through high-definition 3D images, flexible robotic arms and advanced control system. In 2003, Talamini[4] et al. first reported the application of robotic systems in splenectomy. Among the seven reported cases, two cases were converted to laparotomy, so at that time, it was considered that splenectomy was not an ideal indication for robotic surgery. In the field of pediatric surgery, Mbaka[5] et al. summarized and reported 32 cases of RS in children in 2017, showing that the surgical time of RS was shorter than that of LS and there was no significant difference in postoperative complications between them. This study compared and analyzed 35 cases of splenectomy or partial splenectomy, including 14 cases of RS and 21 cases of LS.
1.Operation time
Previous studies showed that RS was associated with a longer operation time[6], associated with the cumbersome installation process and long installation time in the third generation or earlier da Vinci SI system, which led to the prolongation of overall operation time. The fourth generation da Vinci XI system has simplified the installation process and halved the installation time to around 12 minutes. In this study, the operation time in the RS group was slightly shorter than that in the LS group and closely related to the size of the spleen, which reduces operational space for splenomegaly and significantly increasing operation time. The operation time of partial splenectomy is also significantly longer than that of full splenectomy. Single-center comparative studies by Mbaka[5] et al. and Shelby[7] et al. both found that in the case of large spleen volume, the operation time of RS was shorter than that of LS. Shelby et al. reported that the average operation time of RS was 140.5 minutes, which was shorter than 154.9 minutes for the LS group and in the comparative study by Mbaka et al., the average operation time was significantly shortened from 182.4 minutes of LS to 159.6 min for RS. In this study, all 14 children successfully completed da Vinci XI-assisted full or partial splenectomy. The average operation time was 167 minutes, which was shorter than 176 minutes in the LS group although not significant (P = 0.79) and increased spleen volume increased the difference in the operation time between RS and LS.
There are several reasons to explain this difference. The fourth generation da Vinci XI Robotic System is easier to install than the third-generation or earlier SI system, reducing from more than 30 minutes to 12 minutes in the da Vinci XI system. The da Vinci XI Robotic System significantly improves the operation efficiency. Anatomical separation, ligation, hemostasis, as well as the overall operation time has been shortened, particularly in the splenomegaly operation although the small sample number did not allow statistical significance analysis. It is hypothesized that with the update of the system to the fourth generation, operation time is no longer a factor to hinder the application of robot in splenectomy and the robot-assisted surgery even has the advantage of reducing operation time in splenomegaly surgery.
2.Intraoperative blood loss
Both the da Vinci XI and laparoscopic systems rely on a lens to provide the surgical field of view. Their ability to deal with hemorrhage that influences the field of view as well as major abdominal hemorrhage is inferior to traditional laparotomy, so fine dissection is the most effective way to prevent and control intraoperative bleeding. The visual field of the wound and the efficiency of electrocoagulation will be affected by intraoperative bleeding in da Vinci system and it requires washing of the wound to maintain a clear field of view and expose the precise location of hemorrhage. Because the suction fluid is often a mixture of flushing fluid and blood, coupled with factors such as residual fluid in the peritoneal cavity, the amount of hemorrhage cannot often be accurately estimated and is generally estimated by subtracting the amount of rinsing fluid from the total amount of suction fluid. In partial splenectomy, there is often oozing blood from the wound surface of the residual spleen, and the intraoperative blood loss is often more than that in full splenectomy. Qureshi[8], Rescorla[9], Hassan[10], Xu[11], Xi[12], et al. reported a total of 186 cases of LS, with an average bleeding volume of 52 mL. Bhattacharya[13] et al. compared the data of 202 cases of RS and 258 cases of adult LS through meta-analysis and found that the intraoperative blood loss in the RS group was significantly lower than that in the LS group. The data from this study showed that the average blood loss in the RS group was 20 mL, which was significantly less than 51 mL in the LS group, so the da Vinci XI-assisted splenectomy or partial splenectomy procedure reduced intraoperative bleeding.
3.Intraoperative and postoperative complications
Intraoperative and postoperative complications include major intraoperative bleeding, conversion to laparotomy, postoperative incision infection and abdominal cavity residual infection, recurrence, pancreatic injury and postoperative portal vein thrombosis, with complications caused by primary diseases as well as other internal diseases beyond the scope of this article. Mbaka[5] et al. reported 32 cases of robot-assisted splenectomy and there was no postoperative complication case, while two of 23 cases of laparoscopic splenectomy had major postoperative bleeding and conversion to laparotomy. Shelby[7] et al. reported 10 RS cases and 14 LS cases and there were no perioperative complications in either group. The study of Bhattacharya[13] et al. did not find a significant difference in intraoperative and postoperative complications in adult RS and LS patients. Ghidini[14] et al. analyzed the data of 80 pediatric RS cases and their study showed that there was no significant difference in postoperative complications and conversion to laparotomy between the RS and LS group. In this cohort, there was one case of splenic encapsulation effusion in the RS group and each case of abdominal cavity residual infection, peritoneal encapsulation effusion and peritoneal hemorrhage, as well as three cases of conversion to laparotomy were all caused by uncontrollable major intraoperative bleeding in the LS group. The RS and LS groups had no significant difference in postoperative complications and the RS group had a significantly lower rate of major intraoperative bleeding and conversion to laparotomy (P < 0.05). These results suggest that RS can reduce the risk of conversion to laparotomy by improved control of intraoperative bleeding.
4.Length of hospital stay (LOS)
There is a difference in LOS reported in domestic and foreign literature. In the study by Mbaka[5] et al., LOS in the RS group was 3.93 days, which was longer than that in the LS group at 2.9 days. More severe primary disease in the RS group may explain the longer LOS in the RS group. Shelby[7] et al. reported the opposite result where LOS was 2.1 days in the RS group, which was shorter than 3.2 days in the LS group. In China, Tang Yong[15] et al. reported 31 adult RS cases with 9.4 ± 1.9 days of LOS. Qureshi[8] et al. reported that the LOS in LS surgery was 1.4 to 4.5 days. In this study, the mean LOS of the RS group was 8 and 10 days for the LS group. There was no statistical significance between the two groups (P > 0.05), but the LOS in our cohort was longer than that reported in other literature. It is hypothesized that the surgical approach may have a limited effect on LOS, while other factors such as variations in medical environment, concept of rehabilitation and the standard of discharge between China and Western countries affected LOS more significantly.
5.Hospitalization cost
The da Vinci XI robotic system operation and instrument cost was higher than the traditional laparoscope. In our cohort, the average hospitalization cost was 69,000 RMB in the RS group and 32,000 RMB in the LS group. The former was twice as high as the latter and the difference was statistically significant (P = 0.0001). In the United States, Shelby[7] et al. reported that the average hospitalization cost of RS surgery was 44,000 US dollars and 30,000 US dollars for LS surgery, which also showed a significant difference. The high cost of robot-assisted surgery mainly results from two aspects. The first is the high investment and maintenance cost of robotic equipment, up to 20 times higher than ordinary laparoscopy. The second is the depreciation of the robotic equipment. Robotic systems have a limited number of uses and the cost per use is much higher than that of ordinary laparoscopy. The da Vinci XI robotic surgery will increase the financial burden of patients, so it is more viable for wealthy patients or patients with medical insurance.