Surg Endosc DOI 10.1007/s00464-014-3896-9
and Other Interventional Techniques
Single-Incision Robotic Colectomy (SIRC) case series: initial experience at a single center Yen-Yi Juo • Samir Agarwal • Samuel Luka Sean Satey • Vincent Obias
•
Received: 31 March 2014 / Accepted: 12 September 2014 Ó Springer Science+Business Media New York 2014
Abstract Background Laparoscopic colectomy has been associated with favorable outcomes when compared to open colectomy. Single-Incision Robotic Colectomy (SIRC) is a novel procedure hypothesized to improve upon conventional three-port laparoscopic colectomy. We hereby present and analyze our institution’s initial experience with SIRC. Methods We performed a retrospective review of 59 patients who underwent SIRC between May 2010 and September 2013, attempting to identify factors associated with conversion rate and postoperative complication rate. Results Our study included 34 males (57.6 %) and 25 females (42.4 %). The mean age was 60.3 years (range 29–92 years), and the mean BMI was 26.6 kg/m2 (range 14.9–39.7 kg/m2). We identified 31 right hemicolectomies (53.4 %), 20 sigmoid colectomies (34.5 %), 5 left hemicolectomies (1.7 %), 2 low anterior resections (3.5 %), and 1 total colectomy (1.7 %). The overall median operative time was 188 min with an interquartile range of 79 min. Surgical indications included diverticulitis (n = 23, 39.0 %), benign colonic mass (n = 18, 30.5 %), colon cancer (n = 16, 27.1 %), familial adenomatous polyposis (n = 1, 1.7 %), and Crohn’s disease (n = 1, 1.7 %). There were four conversions to open procedure (6.8 %), three conversions to multiport robotic procedure (5.1 %), and one conversion to single-port laparoscopic procedure (1.7 %). Reasons for conversions include difficulty Y.-Y. Juo S. Agarwal S. Luka S. Satey V. Obias (&) Department of Surgery, George Washington University Medical Center, Washington, DC, USA e-mail: [email protected] Y.-Y. Juo e-mail: [email protected]
mobilizing the colon and robotic equipment malfunction. Conversions were associated with both higher complication rates (62.5 vs 25.5 %, p = 0.035) and longer LOS (7.4 vs 4.0 days, p = 0.0003). Postoperative complications occurred in 16 of the 59 cases (27.1 %). Higher BMI was the only significant risk factor for postoperative complications. The overall median LOS was 4 ± 2 days, while the median estimated blood loss was 100 ± 90 ml. Conclusions Our experience has shown that SIRC can be a safe and feasible procedure for both benign and malignant disease. Patient selection is the key to improving surgical outcomes in SIRC. Keywords Robotic surgery Single-incision Colon resection Colorectal surgery Complications Laparoscopic colectomy was associated with decreased intraoperative blood loss, shorter length of stay (LOS), and a lower rate of postoperative ileus [1] versus open colectomy in several prospective randomized trials [2–4] and meta-analyses [5]. This benefit is seen among patients with both malignant [3, 4] and benign [6–8] disease. Laparoscopic colectomy is also associated with a reduction in overall cost due to the decreased LOS and fewer complications [9]. Recently, single-incision techniques have been introduced as an alternative to conventional multiport laparoscopic colectomy. Single-Incision Laparoscopy (SIL) is an approach that attempts to manipulate the laparoscopic camera and instruments through a single skin incision using a multichannel port. Theoretically, the procedure may reduce portrelated complications, decrease postoperative recovery time, and improve cosmesis. To date, SIL has been most frequently utilized for general surgery procedures that require limited exposure and dissection, such as
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appendectomy and cholecystectomy [10, 11]. Recently, several studies have demonstrated the safety and feasibility of SIL in colorectal surgery [12–15]. However, SIL technique shows longer operative times due to ergonomics and visualization with standard instrumentation [16]. The da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) is a minimally invasive approach that enhances instrument articulation and range of motion, visualization and depth perception, and surgical ergonomics. Although several studies show that robotic colectomy is associated with equivalent complication rates and LOS, robotic colectomies incur higher costs and longer operative times compared to conventional three-port laparoscopic colectomy [17–19]. However, robotic surgery decreases the learning curve for surgeons attempting to learn minimally invasive techniques [20]. Presently, several case reports and small series [21–23] have demonstrated the feasibility of Single-Incision Robotic Colectomy (SIRC). The purpose of this study is to analyze our institution’s initial experience with SIRC using a single surgeon’s case series.
Materials and methods Data collection The study was approved by the Institutional Reivew Board at the George Washington University Hospital. Data extraction was performed in a retrospective manner. Between May 2010 and September 2013, fifty-nine patients underwent SIRC in a single institution. Indications for surgery included both benign and malignant disease. No patients received neoadjuvant chemo- or radiotherapy. Patient demographics including gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) score, and prior abdominal surgery were obtained. Operative data included type of operation, operative time, surgical indication, reason for conversion, and estimated blood loss (EBL). Postoperative complications and LOS were reviewed from surgical records. Operative technique All patients are placed in lithotomy position. A single 4 cm vertical incision is made 0.5 cm lateral to the umbilicus. A fascial incision approximately 1 cm longer than the skin incision is then made. A single-incision port (GelPOINT Advanced Access Platform; Applied Medical Inc. Rancho Santa Margarita, CA, USA) is then inserted. Typically, four trocars are placed through the GelPOINT including a 30° robotic scope through a 12 mm trocar, two 8.5 mm robotic
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Fig. 1 Photo of external set up (crossed arms occur under the abdominal wall, not pictured) Patient’s head is to the right of the photo. Four trocars are introduced through the GelPoint, which is placed through the umbilical incision. Two robotic instruments (left, right) and a robotic camera (middle) are pictured. The unoccupied trocar is intended for the surgical assistant 169 9 225 mm (72 9 72 DPI)
trocars, and a 5 mm laparoscopic trocar. Positive-pressure pneumoperitoneum is then established. The robot (da Vinci S-type Surgical System; Intuitive Surgical Inc., Sunnyvale, CA, USA) is docked on the side of the patient near the pathology. The base of the robot is positioned perpendicular to the bed, and the robotic arms are introduced through the trocars. A ‘‘crossed-arm’’ technique is used to minimize instrument clashing and to improve triangulation. The two robotic arms cross each other under the abdominal wall fascia. On the robotic console, the left robotic arm is assigned to the surgeon’s right hand, while the right robotic arm is assigned to the surgeon’s left hand. For a left hemicolectomy and sigmoidectomy, the robot is positioned to the left of the patient. For a right hemicolectomy, the robot is positioned to the right of the patient; for total colectomies, the robot is initially positioned to the right of the patient and intraoperatively re-docked to the left of the patient. The surgical assistant stands opposite to the robot and utilizes the bowel grasper to facilitate exposure (See Fig. 1 for photo of external set up and Fig. 2 for the chosen incision and port placement within the GelPort). The remainder of the procedure, including the sequence of dissection and
Surg Endosc Table 1 Patient demographics, surgical indications, and procedures (n = 59) Patient demographics Age (years)
Mean 60.3 (range 29–92)
Gender (n, %) Male Female
34 (57.6) 25 (42.4)
Body Mass Index (kg/m2)
Mean 26.6 (range 14.9–39.7)
Abdominal wall thickness (cm)
Mean 3.02 (range 0.8–7.2)
ASA Score I
1 (1.5 %)
II
40 (67.8 %)
III Surgical indication Diverticulitis
Fig. 2 Diagram of port placement C, Robotic camera; 1 & 2, left and right robotic instruments; 3, surgical assistant instrument 241 9 280 mm (96 9 96 DPI)
mobilization, is performed similar to techniques employed in laparoscopic colectomy. Statistical analysis Continuous variables such as age and BMI were expressed as mean and range. Other continuous variables that did not assimilate normal distribution such as operative time, EBL, and LOS were expressed as median with their interquartile range (IQR). The mean value of continuous variables was compared using unpaired Student’s t test. The median value of continuous variables was compared using Wilcoxon ranksum test. Comparison of categorical variables was performed using v2 analysis. The Accordion severity grading system was used to classify postoperative complication surgical complications into mild, moderate, and severe complications. In order to identify specific risk factors associated with occurrence of complication and conversion, stratification was used instead of multivariate logistic regression due to the small sample size. The case sequence variable was generated by ordering the patients by procedure date from earliest to latest and was used to assess whether conversion rate or complication rate decreased as the learning curve ascended. To assess the impact of experience on outcome, One-way Analysis of Variance (ANOVA) was used to calculate correlation between case sequence and both complication incidence and operative time. All tests were two-sided with significance level set at a = 0.05. All data transformation and statistical analyses were done using Stata version 12.1 (StataCorp).
18 (30.5 %) 23 (40.0 %)
Benign colonic mass
18 (30.5 %)
Colon cancer
16 (27.1 %)
Familial adenomatous polyposis
1 (1.7 %)
Crohn’s disease
1 (1.7 %)
Procedure Right hemicolectomy
31 (53.4 %)
Sigmoid colectomy
20 (34.5 %)
Left hemicolectomy
5 (8.6 %)
Low anterior resection
2 (3.5 %)
Total colectomy
1 (1.7 %)
Others
1 (1.7 %)
Results During the study period, 59 patients underwent SIRC. Patient demographics, surgical indications, and procedures are summarized in Table 1. The series entailed 34 males (57.6 %) and 25 females (42.4 %) with a mean age of 60.3 years (range 29–92 years). The mean BMI was 26.6 kg/m2 (range 14.9–39.7 kg/m2). Forty Patients (67.8 %) had an ASA score of two, eighteen patients (30.5 %) had an ASA score of three, and one patient (1.7 %) had an ASA score of one. Twelve of the fifty-nine patients (20.3 %) had undergone previous abdominal surgeries. Of the fifty-nine cases, thirty-one were right hemicolectomies (53.4 %), twenty were sigmoid colectomies (34.5 %), five were left hemicolectomies (1.7 %), two were low anterior resections (3.5 %), and one was a total colectomy (1.7 %). Surgical indications included diverticulitis (n = 23, 39.0 %), benign colonic mass (n = 18, 30.5 %), colon cancer (n = 16, 27.1 %), Familial Adenomatous Polyposis (n = 1, 1.7 %), and Crohn’s disease (n = 1, 1.7 %). Overall median operative time was 188 min, with an IQR of 79 min. After removing outliers (operative times that were two standard deviations beyond the mean), the
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Surg Endosc Table 2 Comparison of conversion & non-conversion cases Conversion cases
Non-conversion cases
Mean 63.1 (range 51–78)
Mean 59.9 (range 29–92)
4 (50) 4 (50)
30 (58.8) 21 (41.2)
Body Mass Index (kg/m2)
Mean 26.6 (range 20.7–32.4)
Mean 26.6 (range 14.9–39.7)
Abdominal wall thickness (cm)
Mean 2.6 (range 1.5–3.7)
Mean 3.1 (range 0.8–7.2)
ASA Score of III or higher (n, %)
2 (25)
16 (31.4)
Diverticulitis
6 (75.0 %)
17 (33.3 %)
Benign colonic mass
1 (12.5 %)
17 (33.3 %)
Colon cancer
1 (12.5 %)
15 (29.4 %)
Familial adenomatous polyposis
0 (0 %)
1 (2.0 %)
0 (0 %)
1 (2.0 %)
Mean age (years) Gender (n, %) Male Female
Surgical indication
Crohn’s disease Procedure Right hemicolectomy
1 (14.3 %)
30 (58.0 %)
Sigmoid colectomy
4 (57.1 %)
16 (31.4 %)
Left hemicolectomy
1 (14.3 %)
4 (7.8 %)
Low anterior resection
1 (14.3 %)
1 (1.9 %)
Total colectomy
0 (0 %)
1 (1.9 %)
Others
0 (0 %)
1 (1.9 %)
Complication (n, %)
5 (62.5)
13 (25.5)
Operative time (minutes)
Median 300 (IQR* 111)
Median 180 (IQR* 179)
Length of stay (days)
Median 5.5 (IQR* 7.5)
Median 4 (IQR* 1)
*IQR interquartile range
median operative time for right hemicolectomy was 180 min with an IQR of 43 min, and the median operative time for sigmoid colectomy was 225 min with an IQR of 62 min. No statistically significant trend for operative time could be observed within each procedure category. There were eight intraoperative conversions: four patients were converted to an open procedure (6.8 %), three patients were converted to multiport robotic procedures (5.1 %), and one patient required conversion to a single-port laparoscopic procedure (1.7 %). (See Table 2 for comparison of conversion vs non-conversion cases) Conversions were associated with decreased visualization, adhesions, or malfunctioning laparoscopic equipment. In five cases involved extensive adhesions between the colon and an adjacent organs and/or abdominal wall, that
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prohibited colonic mobilization. In another case, the ureter was bathed inside a phlegmon near the site of diverticulitis; this lead to difficulty dissecting the ureter secondary to the limited mobility provided by single-incision robotic instruments. Two cases were complicated by malfunctioning equipment. In the first case, we were unable to visualize a dislodged anvil from a malfunctioning EEA stapler deep inside the pelvis through the single-port robotic camera. In the second case, there were multiple visualization air leak issues associated with a malfunctioning single-incision access device. There was no statistically significant difference in patient gender, age, ASA class, BMI, surgical indication, case sequence, or presence of previous abdominal surgeries between the conversion and non-conversion groups. However, patients in the conversion group had significantly longer operative times (313.5 vs 187.4 min, p \ 0.0001), higher complication rates (62.5 vs 25.5 %, p = 0.035), and longer LOS (7.4 vs 4.0 days, p = 0.0003). Postoperative complications occurred in sixteen of the fifty-nine cases (27.1 %). Complications included six incisional hernias (10.2 %), five wound infections (8.5 %), three intra-abdominal infections (5.1 %), one wound hematoma (1.7 %), and one postoperative stroke (1.7 %). Of these, one resulted in death, five were classified as severe complications, three moderate complications, and seven mild complications, according to the Accordion Classification [24]. No statistically significant relationship was found between occurrence of postoperative complications and case sequence. No difference in gender, age, previous abdominal surgeries, ASA class, surgical indication, or procedure type was found between patients who experienced complications and those who did not. However, patients who had a complication were noted to have a significantly higher mean BMI (29.1 vs 25.5 kg/m2; p = 0.0179). Median LOS was 4 days, with an IQR of 2 days. The median EBL for the entire case series was 100 ml, with an IQR of 90 ml. Of the 16 cases that underwent surgery for colon cancer, the surgical margins were negative for all cases and the average lymph node yield was 27 (range 17–53).
Discussion Conventional multiport laparoscopic colectomy is associated with either improved or equivalent outcomes when compared to open colectomy in multiple studies [2–4, 25]. SILC attempts to further minimize abdominal trauma and facilitate patient recovery via decreasing the number of incisions. However, since its initial case report in 2008 [26], the procedure has been slow in gaining popularity due to its technical difficulties and prolonged operative times. SIRC aims to surmount these challenges by incorporating
Surg Endosc
the da Vinci S and Si-type Surgical System by incorporating the system’s capacity to ‘‘cross arms’’ while performing SILC. To the extent of our knowledge, our study represents the largest SIRC case series published thus far. In our case series, operative times for right hemicolectomy and sigmoidectomy are 180 ± 43 and 225 ± 65 min, respectively. Despite claims that the incorporation of the robot into single-incision colectomy can lessen the technical challenges and potentially shorten operative time, we find our operative time to be slightly higher than those reported in Vestweber et al’s SILC case series of 224 patients. They report operative times of 142.3 ± 55.4 and 145.6 ± 47.5 min for right hemicolectomy and sigmoidectomy, respectively. However, our patient population consists of a cohort that is overweight, with a mean BMI of 26.6 (range 14.9–39.7). Higher BMI has been associated with longer operative time in previous SILC literature [27]. Although no significant temporal trend in operative time during the course of our study is observed, this is most likely due to the limited number of cases in our series. In accordance with previous literature on the learning curve of minimally-invasive procedures [20, 28], we expect to reduce our operative time as our experience matures. The conversion to open rate in our case series is 6.8 %. This appears similar to those reported for conventional threeport laparoscopic colectomy (9.9 %) and robotic colectomy (5.7 %) in a recent study using a national database [25]. Two of the largest SILC case series also reported a similar conversion rates. Ross reported a 5 % rate [28] while Vestweber reported a 6.3 % rate [29]. We found that the most common reasons for conversion were visualization, adhesive disease, and equipment malfunction. These conversions, besides leading to a longer operative time, resulted in a higher complication rate and longer LOS. While we expect equipment malfunction to improve over time as technology advances, we should focus on appropriate patient selection in order to minimize prolonged operative times. Previous abdominal surgery [30], radiographic evidence of marked inflammation, and aberrant anatomy should all be assessed before the proceeding with a SIRC. The overall complication rate in our case series is 27.1 %. Unlike conversion rate, it is difficult to compare overall complication rates across studies due to disparate definitions of complications and variable follow-up durations. However, the majority (12 of the 16) of our complications were woundrelated, including wound infections, incisional hernias, and wound hematomas. The absence of other commonly observed postoperative complications such as anastomotic leak, intestinal obstruction, cardiac or pulmonary complication, or deep vein thrombosis more likely reflects the fact that only elective procedures were considered for SIRC. We speculate that the increased incisional hernia rate (10.2 %) in comparison with conventional multiport laparoscopic colectomy results from
the single incision through the umbilicus. A recent study by Delaney et al. [31] on laparoscopic colorectal procedures cited an incisional hernia rate of 8.9 % among midline extractions versus 2.3, 3.8, and 4.8 % for muscle-splitting, Pfannenstiel, and ostomy site extractions, respectively. Several previous studies [32, 33] have similar conclusions regarding incisional hernia rates after midline extraction. Another reason for the elevated incisional hernia rate may be the increased stretching and trauma sustained by the single incision during the procedure. It is unlikely that the higher rate is due to the longer incision length, as conventional laparoscopic colectomies also require an eventual 3–5 cm incision for extraction. We also identified obesity as a significant risk factor associated with the occurrence of incisional hernia after colon resection, as was seen in a previous study by Vignali et al. [34] among laparoscopic and open colectomy patients. Whether an increased incisional hernia rate is an incidental finding or represents a true disadvantage associated with SIRC remains to be clarified with future studies involving a larger sample size. Ergonomic advantages provided by SIRC secondary to triangulation and advanced instruments, like the robotic vessel sealer and robotic stapler, are difficult to quantify beyond anecdotal opinions from experienced surgeons. Our operating surgeon feels strongly that utilizing the crossedarm technique in robotic single-incision surgery improves the overall ergonomics of single-incision surgery. The return of triangulation enhances bowel manipulation, vessel isolation, and transection, while the robotic camera provides a stable 3-D platform. Future studies comparing SIRC to conventional multiport or single-port laparoscopic colectomy are recommended to further define the benefits of single-incision robotic surgery. In conclusion, our experience has shown that SIRC is a safe and feasible procedure for both benign and malignant disease. The results of our analysis show that the presence of intra-abdominal adhesions and obesity is the most important factors leading to conversion and postoperative complications. Refinement of patient selection criteria is the key to improving future outcomes.
Disclosures Dr Obias is a consultant for Intuitive Surgical. Inc. Dr. Juo, Dr. Luka, Dr. Satey, and Dr. Agarwal have no conflicts of interest or financial ties to disclose.
References 1. The Clinical Outcomes of Surgical Therapy Study Group (2004) A comparison of laparoscopically assisted and open colectomy for colon cancer. N Engl J Med 350:2050–9 2. Reibetanz J, Germer CT (2013) Laparoscopic vs open surgery in colorectal cancer: the 10-year results of the CLASICC trial. Chirurg 84:234
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19. Tyler JA, Fox JP, Desai MM, Perry WB, Glasgow SC (2013) Outcomes and costs associated with robotic colectomy in the minimally invasive era. Dis Colon Rectum 56:458–466 20. Yohannes P, Rotariu P, Pinto P, Smith AD, Lee BR (2002) Comparison of robotic versus laparoscopic skills: is there a difference in the learning curve? Urology 60:39–45 discussion 21. Morelli L, Guadagni S, Caprili G, Di Candio G, Boggi U, Mosca F (2011) Robotic right colectomy using the Da Vinci SingleSite(R) platform: case report. Int J Med Robot 9:258–261 22. Ostrowitz MB, Eschete D, Zemon H, DeNoto G (2009) Roboticassisted single-incision right colectomy: early experience. Int J Med Robot 5:465–470 23. Ragupathi M, Ramos-Valadez DI, Pedraza R, Haas EM (2010) Robotic-assisted single-incision laparoscopic partial cecectomy. Int J Med Robot 6:362–367 24. Strasberg SM, Linehan DC, Hawkins WG (2009) The accordion severity grading system of surgical complications. Ann Surg 250:177–186 25. Juo YY, Hyder O, Haider AH, Camp M, Lidor A, Ahuja N. Is minimally invasive colon resection better than traditional approaches?: First comprehensive national examination with propensity score matching. JAMA Surg 149:177–184. doi:10. 1001/jamasurg.2013.3660 26. Bucher P, Pugin F, Morel P (2008) Single port access laparoscopic right hemicolectomy. Int J Colorectal Dis 23:1013–1016 27. Ramos-Valadez DI, Patel CB, Ragupathi M, Bartley Pickron T, Haas EM (2010) Single-incision laparoscopic right hemicolectomy: safety and feasibility in a series of consecutive cases. Surg Endosc 24:2613–2616 28. Ross H, Steele S, Whiteford M et al (2011) Early multi-institution experience with single-incision laparoscopic colectomy. Dis Colon Rectum 54:187–192 29. Vestweber B, Galetin T, Lammerting K et al (2013) Singleincision laparoscopic surgery: outcomes from 224 colonic resections performed at a single center using SILS. Surg Endosc 27:434–442 30. Kossi JA, Salminen PT, Laato MK (2004) Surgical workload and cost of postoperative adhesion-related intestinal obstruction: importance of previous surgery. World J Surg 28:666–670 31. Samia H, Lawrence J, Nobel T, Stein S, Champagne BJ, Delaney CP (2013) Extraction site location and incisional hernias after laparoscopic colorectal surgery: should we be avoiding the midline? Am J Surg 205:264–267 discussion 8 32. Lee L, Mappin-Kasirer B, Sender Liberman A et al (2012) High incidence of symptomatic incisional hernia after midline extraction in laparoscopic colon resection. Surg Endosc 26:3180–3185 33. Singh R, Omiccioli A, Hegge S, McKinley C (2008) Does the extraction-site location in laparoscopic colorectal surgery have an impact on incisional hernia rates? Surg Endosc 22:2596–2600 34. Vignali A, De Nardi P, Ghirardelli L, Di Palo S, Staudacher C (2013) Short and long-term outcomes of laparoscopic colectomy in obese patients. World J Gastroenterol 19:7405–7411
and Other Interventional Techniques
Single-Incision Robotic Colectomy (SIRC) case series: initial experience at a single center Yen-Yi Juo • Samir Agarwal • Samuel Luka Sean Satey • Vincent Obias
•
Received: 31 March 2014 / Accepted: 12 September 2014 Ó Springer Science+Business Media New York 2014
Abstract Background Laparoscopic colectomy has been associated with favorable outcomes when compared to open colectomy. Single-Incision Robotic Colectomy (SIRC) is a novel procedure hypothesized to improve upon conventional three-port laparoscopic colectomy. We hereby present and analyze our institution’s initial experience with SIRC. Methods We performed a retrospective review of 59 patients who underwent SIRC between May 2010 and September 2013, attempting to identify factors associated with conversion rate and postoperative complication rate. Results Our study included 34 males (57.6 %) and 25 females (42.4 %). The mean age was 60.3 years (range 29–92 years), and the mean BMI was 26.6 kg/m2 (range 14.9–39.7 kg/m2). We identified 31 right hemicolectomies (53.4 %), 20 sigmoid colectomies (34.5 %), 5 left hemicolectomies (1.7 %), 2 low anterior resections (3.5 %), and 1 total colectomy (1.7 %). The overall median operative time was 188 min with an interquartile range of 79 min. Surgical indications included diverticulitis (n = 23, 39.0 %), benign colonic mass (n = 18, 30.5 %), colon cancer (n = 16, 27.1 %), familial adenomatous polyposis (n = 1, 1.7 %), and Crohn’s disease (n = 1, 1.7 %). There were four conversions to open procedure (6.8 %), three conversions to multiport robotic procedure (5.1 %), and one conversion to single-port laparoscopic procedure (1.7 %). Reasons for conversions include difficulty Y.-Y. Juo S. Agarwal S. Luka S. Satey V. Obias (&) Department of Surgery, George Washington University Medical Center, Washington, DC, USA e-mail: [email protected] Y.-Y. Juo e-mail: [email protected]
mobilizing the colon and robotic equipment malfunction. Conversions were associated with both higher complication rates (62.5 vs 25.5 %, p = 0.035) and longer LOS (7.4 vs 4.0 days, p = 0.0003). Postoperative complications occurred in 16 of the 59 cases (27.1 %). Higher BMI was the only significant risk factor for postoperative complications. The overall median LOS was 4 ± 2 days, while the median estimated blood loss was 100 ± 90 ml. Conclusions Our experience has shown that SIRC can be a safe and feasible procedure for both benign and malignant disease. Patient selection is the key to improving surgical outcomes in SIRC. Keywords Robotic surgery Single-incision Colon resection Colorectal surgery Complications Laparoscopic colectomy was associated with decreased intraoperative blood loss, shorter length of stay (LOS), and a lower rate of postoperative ileus [1] versus open colectomy in several prospective randomized trials [2–4] and meta-analyses [5]. This benefit is seen among patients with both malignant [3, 4] and benign [6–8] disease. Laparoscopic colectomy is also associated with a reduction in overall cost due to the decreased LOS and fewer complications [9]. Recently, single-incision techniques have been introduced as an alternative to conventional multiport laparoscopic colectomy. Single-Incision Laparoscopy (SIL) is an approach that attempts to manipulate the laparoscopic camera and instruments through a single skin incision using a multichannel port. Theoretically, the procedure may reduce portrelated complications, decrease postoperative recovery time, and improve cosmesis. To date, SIL has been most frequently utilized for general surgery procedures that require limited exposure and dissection, such as
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appendectomy and cholecystectomy [10, 11]. Recently, several studies have demonstrated the safety and feasibility of SIL in colorectal surgery [12–15]. However, SIL technique shows longer operative times due to ergonomics and visualization with standard instrumentation [16]. The da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) is a minimally invasive approach that enhances instrument articulation and range of motion, visualization and depth perception, and surgical ergonomics. Although several studies show that robotic colectomy is associated with equivalent complication rates and LOS, robotic colectomies incur higher costs and longer operative times compared to conventional three-port laparoscopic colectomy [17–19]. However, robotic surgery decreases the learning curve for surgeons attempting to learn minimally invasive techniques [20]. Presently, several case reports and small series [21–23] have demonstrated the feasibility of Single-Incision Robotic Colectomy (SIRC). The purpose of this study is to analyze our institution’s initial experience with SIRC using a single surgeon’s case series.
Materials and methods Data collection The study was approved by the Institutional Reivew Board at the George Washington University Hospital. Data extraction was performed in a retrospective manner. Between May 2010 and September 2013, fifty-nine patients underwent SIRC in a single institution. Indications for surgery included both benign and malignant disease. No patients received neoadjuvant chemo- or radiotherapy. Patient demographics including gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) score, and prior abdominal surgery were obtained. Operative data included type of operation, operative time, surgical indication, reason for conversion, and estimated blood loss (EBL). Postoperative complications and LOS were reviewed from surgical records. Operative technique All patients are placed in lithotomy position. A single 4 cm vertical incision is made 0.5 cm lateral to the umbilicus. A fascial incision approximately 1 cm longer than the skin incision is then made. A single-incision port (GelPOINT Advanced Access Platform; Applied Medical Inc. Rancho Santa Margarita, CA, USA) is then inserted. Typically, four trocars are placed through the GelPOINT including a 30° robotic scope through a 12 mm trocar, two 8.5 mm robotic
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Fig. 1 Photo of external set up (crossed arms occur under the abdominal wall, not pictured) Patient’s head is to the right of the photo. Four trocars are introduced through the GelPoint, which is placed through the umbilical incision. Two robotic instruments (left, right) and a robotic camera (middle) are pictured. The unoccupied trocar is intended for the surgical assistant 169 9 225 mm (72 9 72 DPI)
trocars, and a 5 mm laparoscopic trocar. Positive-pressure pneumoperitoneum is then established. The robot (da Vinci S-type Surgical System; Intuitive Surgical Inc., Sunnyvale, CA, USA) is docked on the side of the patient near the pathology. The base of the robot is positioned perpendicular to the bed, and the robotic arms are introduced through the trocars. A ‘‘crossed-arm’’ technique is used to minimize instrument clashing and to improve triangulation. The two robotic arms cross each other under the abdominal wall fascia. On the robotic console, the left robotic arm is assigned to the surgeon’s right hand, while the right robotic arm is assigned to the surgeon’s left hand. For a left hemicolectomy and sigmoidectomy, the robot is positioned to the left of the patient. For a right hemicolectomy, the robot is positioned to the right of the patient; for total colectomies, the robot is initially positioned to the right of the patient and intraoperatively re-docked to the left of the patient. The surgical assistant stands opposite to the robot and utilizes the bowel grasper to facilitate exposure (See Fig. 1 for photo of external set up and Fig. 2 for the chosen incision and port placement within the GelPort). The remainder of the procedure, including the sequence of dissection and
Surg Endosc Table 1 Patient demographics, surgical indications, and procedures (n = 59) Patient demographics Age (years)
Mean 60.3 (range 29–92)
Gender (n, %) Male Female
34 (57.6) 25 (42.4)
Body Mass Index (kg/m2)
Mean 26.6 (range 14.9–39.7)
Abdominal wall thickness (cm)
Mean 3.02 (range 0.8–7.2)
ASA Score I
1 (1.5 %)
II
40 (67.8 %)
III Surgical indication Diverticulitis
Fig. 2 Diagram of port placement C, Robotic camera; 1 & 2, left and right robotic instruments; 3, surgical assistant instrument 241 9 280 mm (96 9 96 DPI)
mobilization, is performed similar to techniques employed in laparoscopic colectomy. Statistical analysis Continuous variables such as age and BMI were expressed as mean and range. Other continuous variables that did not assimilate normal distribution such as operative time, EBL, and LOS were expressed as median with their interquartile range (IQR). The mean value of continuous variables was compared using unpaired Student’s t test. The median value of continuous variables was compared using Wilcoxon ranksum test. Comparison of categorical variables was performed using v2 analysis. The Accordion severity grading system was used to classify postoperative complication surgical complications into mild, moderate, and severe complications. In order to identify specific risk factors associated with occurrence of complication and conversion, stratification was used instead of multivariate logistic regression due to the small sample size. The case sequence variable was generated by ordering the patients by procedure date from earliest to latest and was used to assess whether conversion rate or complication rate decreased as the learning curve ascended. To assess the impact of experience on outcome, One-way Analysis of Variance (ANOVA) was used to calculate correlation between case sequence and both complication incidence and operative time. All tests were two-sided with significance level set at a = 0.05. All data transformation and statistical analyses were done using Stata version 12.1 (StataCorp).
18 (30.5 %) 23 (40.0 %)
Benign colonic mass
18 (30.5 %)
Colon cancer
16 (27.1 %)
Familial adenomatous polyposis
1 (1.7 %)
Crohn’s disease
1 (1.7 %)
Procedure Right hemicolectomy
31 (53.4 %)
Sigmoid colectomy
20 (34.5 %)
Left hemicolectomy
5 (8.6 %)
Low anterior resection
2 (3.5 %)
Total colectomy
1 (1.7 %)
Others
1 (1.7 %)
Results During the study period, 59 patients underwent SIRC. Patient demographics, surgical indications, and procedures are summarized in Table 1. The series entailed 34 males (57.6 %) and 25 females (42.4 %) with a mean age of 60.3 years (range 29–92 years). The mean BMI was 26.6 kg/m2 (range 14.9–39.7 kg/m2). Forty Patients (67.8 %) had an ASA score of two, eighteen patients (30.5 %) had an ASA score of three, and one patient (1.7 %) had an ASA score of one. Twelve of the fifty-nine patients (20.3 %) had undergone previous abdominal surgeries. Of the fifty-nine cases, thirty-one were right hemicolectomies (53.4 %), twenty were sigmoid colectomies (34.5 %), five were left hemicolectomies (1.7 %), two were low anterior resections (3.5 %), and one was a total colectomy (1.7 %). Surgical indications included diverticulitis (n = 23, 39.0 %), benign colonic mass (n = 18, 30.5 %), colon cancer (n = 16, 27.1 %), Familial Adenomatous Polyposis (n = 1, 1.7 %), and Crohn’s disease (n = 1, 1.7 %). Overall median operative time was 188 min, with an IQR of 79 min. After removing outliers (operative times that were two standard deviations beyond the mean), the
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Surg Endosc Table 2 Comparison of conversion & non-conversion cases Conversion cases
Non-conversion cases
Mean 63.1 (range 51–78)
Mean 59.9 (range 29–92)
4 (50) 4 (50)
30 (58.8) 21 (41.2)
Body Mass Index (kg/m2)
Mean 26.6 (range 20.7–32.4)
Mean 26.6 (range 14.9–39.7)
Abdominal wall thickness (cm)
Mean 2.6 (range 1.5–3.7)
Mean 3.1 (range 0.8–7.2)
ASA Score of III or higher (n, %)
2 (25)
16 (31.4)
Diverticulitis
6 (75.0 %)
17 (33.3 %)
Benign colonic mass
1 (12.5 %)
17 (33.3 %)
Colon cancer
1 (12.5 %)
15 (29.4 %)
Familial adenomatous polyposis
0 (0 %)
1 (2.0 %)
0 (0 %)
1 (2.0 %)
Mean age (years) Gender (n, %) Male Female
Surgical indication
Crohn’s disease Procedure Right hemicolectomy
1 (14.3 %)
30 (58.0 %)
Sigmoid colectomy
4 (57.1 %)
16 (31.4 %)
Left hemicolectomy
1 (14.3 %)
4 (7.8 %)
Low anterior resection
1 (14.3 %)
1 (1.9 %)
Total colectomy
0 (0 %)
1 (1.9 %)
Others
0 (0 %)
1 (1.9 %)
Complication (n, %)
5 (62.5)
13 (25.5)
Operative time (minutes)
Median 300 (IQR* 111)
Median 180 (IQR* 179)
Length of stay (days)
Median 5.5 (IQR* 7.5)
Median 4 (IQR* 1)
*IQR interquartile range
median operative time for right hemicolectomy was 180 min with an IQR of 43 min, and the median operative time for sigmoid colectomy was 225 min with an IQR of 62 min. No statistically significant trend for operative time could be observed within each procedure category. There were eight intraoperative conversions: four patients were converted to an open procedure (6.8 %), three patients were converted to multiport robotic procedures (5.1 %), and one patient required conversion to a single-port laparoscopic procedure (1.7 %). (See Table 2 for comparison of conversion vs non-conversion cases) Conversions were associated with decreased visualization, adhesions, or malfunctioning laparoscopic equipment. In five cases involved extensive adhesions between the colon and an adjacent organs and/or abdominal wall, that
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prohibited colonic mobilization. In another case, the ureter was bathed inside a phlegmon near the site of diverticulitis; this lead to difficulty dissecting the ureter secondary to the limited mobility provided by single-incision robotic instruments. Two cases were complicated by malfunctioning equipment. In the first case, we were unable to visualize a dislodged anvil from a malfunctioning EEA stapler deep inside the pelvis through the single-port robotic camera. In the second case, there were multiple visualization air leak issues associated with a malfunctioning single-incision access device. There was no statistically significant difference in patient gender, age, ASA class, BMI, surgical indication, case sequence, or presence of previous abdominal surgeries between the conversion and non-conversion groups. However, patients in the conversion group had significantly longer operative times (313.5 vs 187.4 min, p \ 0.0001), higher complication rates (62.5 vs 25.5 %, p = 0.035), and longer LOS (7.4 vs 4.0 days, p = 0.0003). Postoperative complications occurred in sixteen of the fifty-nine cases (27.1 %). Complications included six incisional hernias (10.2 %), five wound infections (8.5 %), three intra-abdominal infections (5.1 %), one wound hematoma (1.7 %), and one postoperative stroke (1.7 %). Of these, one resulted in death, five were classified as severe complications, three moderate complications, and seven mild complications, according to the Accordion Classification [24]. No statistically significant relationship was found between occurrence of postoperative complications and case sequence. No difference in gender, age, previous abdominal surgeries, ASA class, surgical indication, or procedure type was found between patients who experienced complications and those who did not. However, patients who had a complication were noted to have a significantly higher mean BMI (29.1 vs 25.5 kg/m2; p = 0.0179). Median LOS was 4 days, with an IQR of 2 days. The median EBL for the entire case series was 100 ml, with an IQR of 90 ml. Of the 16 cases that underwent surgery for colon cancer, the surgical margins were negative for all cases and the average lymph node yield was 27 (range 17–53).
Discussion Conventional multiport laparoscopic colectomy is associated with either improved or equivalent outcomes when compared to open colectomy in multiple studies [2–4, 25]. SILC attempts to further minimize abdominal trauma and facilitate patient recovery via decreasing the number of incisions. However, since its initial case report in 2008 [26], the procedure has been slow in gaining popularity due to its technical difficulties and prolonged operative times. SIRC aims to surmount these challenges by incorporating
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the da Vinci S and Si-type Surgical System by incorporating the system’s capacity to ‘‘cross arms’’ while performing SILC. To the extent of our knowledge, our study represents the largest SIRC case series published thus far. In our case series, operative times for right hemicolectomy and sigmoidectomy are 180 ± 43 and 225 ± 65 min, respectively. Despite claims that the incorporation of the robot into single-incision colectomy can lessen the technical challenges and potentially shorten operative time, we find our operative time to be slightly higher than those reported in Vestweber et al’s SILC case series of 224 patients. They report operative times of 142.3 ± 55.4 and 145.6 ± 47.5 min for right hemicolectomy and sigmoidectomy, respectively. However, our patient population consists of a cohort that is overweight, with a mean BMI of 26.6 (range 14.9–39.7). Higher BMI has been associated with longer operative time in previous SILC literature [27]. Although no significant temporal trend in operative time during the course of our study is observed, this is most likely due to the limited number of cases in our series. In accordance with previous literature on the learning curve of minimally-invasive procedures [20, 28], we expect to reduce our operative time as our experience matures. The conversion to open rate in our case series is 6.8 %. This appears similar to those reported for conventional threeport laparoscopic colectomy (9.9 %) and robotic colectomy (5.7 %) in a recent study using a national database [25]. Two of the largest SILC case series also reported a similar conversion rates. Ross reported a 5 % rate [28] while Vestweber reported a 6.3 % rate [29]. We found that the most common reasons for conversion were visualization, adhesive disease, and equipment malfunction. These conversions, besides leading to a longer operative time, resulted in a higher complication rate and longer LOS. While we expect equipment malfunction to improve over time as technology advances, we should focus on appropriate patient selection in order to minimize prolonged operative times. Previous abdominal surgery [30], radiographic evidence of marked inflammation, and aberrant anatomy should all be assessed before the proceeding with a SIRC. The overall complication rate in our case series is 27.1 %. Unlike conversion rate, it is difficult to compare overall complication rates across studies due to disparate definitions of complications and variable follow-up durations. However, the majority (12 of the 16) of our complications were woundrelated, including wound infections, incisional hernias, and wound hematomas. The absence of other commonly observed postoperative complications such as anastomotic leak, intestinal obstruction, cardiac or pulmonary complication, or deep vein thrombosis more likely reflects the fact that only elective procedures were considered for SIRC. We speculate that the increased incisional hernia rate (10.2 %) in comparison with conventional multiport laparoscopic colectomy results from
the single incision through the umbilicus. A recent study by Delaney et al. [31] on laparoscopic colorectal procedures cited an incisional hernia rate of 8.9 % among midline extractions versus 2.3, 3.8, and 4.8 % for muscle-splitting, Pfannenstiel, and ostomy site extractions, respectively. Several previous studies [32, 33] have similar conclusions regarding incisional hernia rates after midline extraction. Another reason for the elevated incisional hernia rate may be the increased stretching and trauma sustained by the single incision during the procedure. It is unlikely that the higher rate is due to the longer incision length, as conventional laparoscopic colectomies also require an eventual 3–5 cm incision for extraction. We also identified obesity as a significant risk factor associated with the occurrence of incisional hernia after colon resection, as was seen in a previous study by Vignali et al. [34] among laparoscopic and open colectomy patients. Whether an increased incisional hernia rate is an incidental finding or represents a true disadvantage associated with SIRC remains to be clarified with future studies involving a larger sample size. Ergonomic advantages provided by SIRC secondary to triangulation and advanced instruments, like the robotic vessel sealer and robotic stapler, are difficult to quantify beyond anecdotal opinions from experienced surgeons. Our operating surgeon feels strongly that utilizing the crossedarm technique in robotic single-incision surgery improves the overall ergonomics of single-incision surgery. The return of triangulation enhances bowel manipulation, vessel isolation, and transection, while the robotic camera provides a stable 3-D platform. Future studies comparing SIRC to conventional multiport or single-port laparoscopic colectomy are recommended to further define the benefits of single-incision robotic surgery. In conclusion, our experience has shown that SIRC is a safe and feasible procedure for both benign and malignant disease. The results of our analysis show that the presence of intra-abdominal adhesions and obesity is the most important factors leading to conversion and postoperative complications. Refinement of patient selection criteria is the key to improving future outcomes.
Disclosures Dr Obias is a consultant for Intuitive Surgical. Inc. Dr. Juo, Dr. Luka, Dr. Satey, and Dr. Agarwal have no conflicts of interest or financial ties to disclose.
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