ECSPECT prospective multicentre registry for single-port laparoscopic colorectal procedures


Abstract

Background

The international multicentre registry ECSPECT (European Consensus of Single Port Expertise in Colorectal Treatment) was established to evaluate the general feasibility and safety of single-port colorectal surgery with regard to preoperative risk assessment.

Methods

Consecutive patients undergoing single-port colorectal surgery were enrolled from 11 European centres between March 2010 and March 2014. Data were analysed to assess patient-, technique- and procedure-dependent parameters. A validated sex-adjusted risk chart was developed for prediction of single-port colorectal surgery-related conversion and complications.

Results

Some 1769 patients were enrolled, 937 with benign and 832 with malignant conditions. Procedures were completed without additional trocars in 1628 patients (92·0 per cent). Conversion to open surgery was required in 75 patients (4·2 per cent) and was related to male sex and ASA fitness grade exceeding I. Conversions were more frequent in pelvic procedures involving the rectum compared with abdominal procedures (8·1 versus 3·2 per cent; odds ratio 2·69, P < 0·001). Postoperative complications were observed in a total of 224 patients (12·7 per cent). Independent predictors of complications included male sex (P < 0·001), higher ASA grade (P = 0·006) and rectal procedures (P =0·002). The overall 30-day mortality rate was 0·5 per cent (8 of 1769 patients); three deaths (0·2 per cent; 1 blood loss, 2 leaks) were attributable to surgical causes.

Conclusion

The feasibility and safety, conversion and complication profile demonstrated here provides guidance for patient selection.

Introduction

Laparoscopic colorectal surgery is well established as an alternative to conventional open resection, and has been shown to be associated with short-term benefits, including earlier postoperative recovery, decreased postoperative pain, reduced impairment of pulmonary function and shorter hospital stay[1, 2]. Minimally invasive laparoscopic colorectal surgery is conventionally performed using several trocar sites and a separate incision for specimen extraction (multiport laparoscopic colorectal surgery). However, each incision has the potential for bleeding, haematoma, infection and incisional hernia. Single-port colorectal surgery has been used in recent years for both benign and malignant colorectal surgery[3-5]. Nevertheless, despite the potential advantages of single-port colorectal surgery, any innovative technique requires evaluation of its feasibility and safety before gaining wider acceptance[6]. To date, the literature on single-port colorectal surgery is limited to small case series and comparative studies. Furthermore, indications and preoperative selection criteria for the single-port colorectal surgery technique remain unclear, and risk factors for conversions and complications have not been established. Therefore, a multi-institutional European study group (ECSPECT) was established to assess the risk and safety of single-port colorectal surgery.

Methods

The objective of this study was to evaluate the safety and feasibility of single-port colorectal surgery. Thus, particular efforts were made to assess risk and complications, with the further objective of developing a complication risk chart. All surgical procedures were performed primarily using single-port access with only one abdominal incision. Use of any additional trocar was registered but not considered a complication itself. Intraoperative complications were defined as unintentional events that required deviation from the standard technique.

Procedures were classified as proximal or distal abdominal surgery, with the proximal category including right and left colonic resections, and distal incorporating all those with pelvic dissection for rectal resection, abdominoperineal resection (APR) and restorative proctocolectomy.

Postoperative complications were graded according to the Dindo–Demartines–Clavien classification[7]. An anastomotic leak was defined by: radiological demonstration of contrast extravasation; diffuse peritonitis with the presence of faecal fluid at reoperation; presence of a local abscess in the vicinity of the anastomosis; or faecal discharge from the drain or wound[8]. Operative mortality was defined as death from any cause during or after surgery within 30 days if the patient was discharged from hospital, or within any interval if the patient was not discharged.

Data collection

The local institutional review board for clinical trials approved the study and all patients gave informed consent. The clinical effectiveness committees of the participating centres considered this technique to be a formal laparoscopic method. To limit bias owing to heterogeneous learning curves, one surgeon responsible for the colorectal programme in each centre had performed more than 100 single-port colorectal surgery procedures before enrolment. Procedure numbers varied in relation to the preferences for the single-port approach in each centre. Five centres predominantly included patients with left-sided colectomies, whereas two centres mainly performed right colonic resections. Lower single-port procedures such as restorative proctocolectomy, rectal resections and APR were performed in seven of the 11 centres. The hospital data and records included medical notes and operating reports for all hospital admissions, and included patient-, technique- and procedure-dependent variables. All data were blinded and monitored by independent investigators. Data were then entered into the ECSPECT registry system, based on Microsoft Access® (Microsoft, Redmond, Washington, USA), by local study assistants who were unaware of patient identities. Patients were seen at an outpatient clinic 1 month after surgery, or had telephone interviews with study assistants. As such, the 30-day follow-up was 100 per cent complete.

Statistical analysis

In this prospective observational study, potential risk factors were investigated by means of univariable analyses; Fisher’s exact test and χ2 test were used for categorical variables, and the Wilcoxon rank-sum test or Kruskal–Wallis test for continuous variables. A univariable logistic regression analysis was also performed. Multivariable logistic regression models were fitted for conversion and complication as dependent variables. A risk score based on the estimated conversion and complication probabilities was devised: low risk corresponded to an estimated probability below the median for the patient group considered; moderate risk was scored between the median and the 90 per cent quantile and high risk above the 90 per cent quantile. Statistical analyses were carried out using R software version 3.0.3 (http://www.r-project.org). All statistical assessments were two-sided and a significance level of 0·050 was used.

Results

The ECSPECT registry includes data on 2032 consecutive patients who underwent single-port colorectal surgery between March 2010 and March 2014 at 11 centres in Austria, Denmark, Germany, Italy, the Netherlands, Spain, Switzerland and the UK. The surgical procedures (single-port colorectal surgery as a proportion of the total number of colorectal procedures) were performed in Leverkusen (638 of 1070), Salzburg (360 of 613), Turin (263 of 490), Varese (173 of 265), Bristol (145 of 310), St Gallen (142 of 451), Seville (109 of 210), Vienna (81 of 132), Amsterdam (49 of 130), Copenhagen (39 of 765) and Bremerhaven (33 of 114). Reasons for non-eligibility for single-port colorectal surgery were: cT4 tumours, bulky lymph nodules attached to vital pedicles (such as superior mesenteric vein in right colectomies), emergency procedure, or non-availability of the surgeon experienced in single-port colorectal surgery. The complete data were registered in a central database. A random group of 263 patients was excluded before any analysis and used as internal validation for the risk charts, leaving 1769 complete data sets as the study group for review and analyses.

Demographic characteristics according to the single-port procedures performed are shown in Table 1. As expected, sex differences were found between proximal procedure types without rectal involvement (right and left colectomies) and distal abdominal procedures (restorative proctocolectomy, APR and rectal resections). Younger patients were more likely to undergo restorative proctocolectomy or left colonic resections (Fig. S1a, supporting information), probably a result of the higher rates of inflammatory bowel disease in this cohort. There were no differences in distribution of ASA grades for proximal versus distal procedures: 25·5 versus 22·5 per cent ASA I, 54·3 versus 59·7 per cent ASA II, 18·7 versus 16·5 per cent ASA III, and 0·4 versus 0·5 per cent ASA IV, respectively (P = 0·297). However, among patients with ASA III and IV the single-port approach was used more often for right colonic resections than for all other procedures (Fig. S1b, supporting information). In contrast to left colectomies and restorative proctocolectomies, right colectomies, rectal resections and APR were performed significantly more often for malignancies. The histopathological staging of the malignant disease is shown in Table 2.

Table 1. Demographic data for patients who underwent single-incision laparoscopic surgery, in total and according to surgical procedure
Total Right colectomy Left colectomy Rectal resection Abdominoperineal resection Restorative proctocolectomy
(n = 1769) (n = 519) (n = 868) (n = 214) (n = 48) (n = 120) P
  • Values in parentheses are percentages unless indicated otherwise;
  • *values are mean(s.d.) (range).
  • χ2 test, except
  • Kruskal–Wallis test.
Age (years)* 61·1(14·4) 64·5(15·5) 60·2(12·2) 62·7(12·9) 65·9(13·3) 48·6(18·5) < 0·001
(13–93) (13–92) (21–89) (22–93) (23–88) (17–90)
Sex ratio (F : M) 913 : 856 275 : 244 465 : 403 100 : 114 16 : 32 57 : 63 0·026
BMI (kg/m2)* 26·0(4·6) 25·9(4·8) 26·4(4·6) 25·7(4·5) 25·2(4·0) 25·4(5·1) 0·020
(15–52) (16–52) (15–47) (17–48) (16–36) (16–45)
ASA fitness grade
I 439 (24·8) 132 (25·4) 221 (25·5) 62 (29·0) 3 (6) 21 (17·5) 0·005
II 981 (55·5) 242 (46·6) 511 (58·9) 112 (52·3) 38 (79) 78 (65·0) < 0·001
III 323 (18·3) 133 (25·6) 127 (14·6) 36 (16·8) 7 (15) 20 (16·7) < 0·001
IV 8 (0·5) 6 (1·2) 0 (0) 2 (0·9) 0 (0) 0 (0) 0·011
Not assessed 18 (1·0) 6 (1·2) 9 (1·0) 2 (0·9) 0 (0) 1 (0·8)
Disease type < 0·001
Benign 937 (53·0) 170 (32·8) 644 (74·2) 29 (13·6) 2 (4) 92 (76·7)
Malignant 832 (47·0) 349 (67·2) 224 (25·8) 185 (86·4) 46 (96) 28 (23·3)
Table 2. Tumour staging in patients with malignancy
Total Right colectomy Left colectomy Rectal resection Abdominoperineal resection Restorative proctocolectomy
(n = 832) (n = 349) (n = 224) (n = 185) (n = 46) (n = 28) P
  • Values in parentheses are percentages followed by standardized residuals unless indicated otherwise;
  • *values are mean(s.d).
  • χ2 test, except
  • Kruskal–Wallis test.
Tumour category < 0·001
ypT0/pTis 54 (6·5) 34 (9·7) 6 (2·7) 8 (4·3) 2 (4) 4 (14)
(3·24) (–2·71) (–1·36) (–0·61) (1·70)
pT1 125 (15·0) 34 (9·7) 49 (21·9) 24 (13·0) 5 (11) 13 (46)
(–3·62) (3·36) (–0·89) (–0·81) (4·73)
pT2 194 (23·3) 74 (21·2) 40 (17·9) 53 (28·6) 22 (48) 5 (18)
(–1·23) (–2·26) (1·94) (4·04) (–0·70)
pT3 451 (54·2) 203 (58·2) 128 (57·1) 98 (53·0) 17 (37) 5 (18)
(1·95) (1·03) (–0·38) (–2·42) (–3·93)
pT4 8 (1·0) 4 (1·1) 1 (0·4) 2 (1·1) 0 (0) 1 (4)
(0·46) (–0·92) (0·19) (–0·69) (1·44)
Node category 0·031
pN0 409 (49·2) 172 (49·3) 129 (57·6) 71 (38·4) 20 (43) 17 (61)
(0·06) (2·95) (–3·33) (–0·79) (1·24)
pN1 160 (19·2) 68 (19·5) 45 (20·1) 30 (16·2) 13 (28) 4 (14)
(0·16) (0·38) (–1·18) (1·60) (–0·68)
pN2 83 (10·0) 43 (12·3) 17 (7·6) 22 (11·9) 1 (2) 0 (0)
(1·92) (–1·39) (0·99) (–1·82) (–1·79)
Not assessed 180 (21·6) 66 (18·9) 33 (14·7) 62 (33·5) 12 (26) 7 (25)
(–1·62) (–2·93) (4·45) (0·75) (0·44)
No. of nodes retrieved* 18·00(8·55) 16·53(9·64) 16·74(9·61) 17·58(7·34) 15·07(6·17) 8·37(15·60) 0·133
Metastasis category < 0·001
pM0 614 (73·8) 266 (76·2) 181 (80·8) 136 (73·5) 23 (50) 8 (29)
(1·35) (2·79) (–0·10) (–3·78) (–5·54)
pM1 100 (12·0) 28 (8·0) 29 (12·9) 25 (13·5) 12 (26) 6 (21)
(–3·01) (0·50) (0·71) (3·02) (1·56)
Not assessed 118 (14·2) 55 (15·8) 14 (6·3) 24 (13·0) 11 (24) 14 (50)
(1·11) (–3·98) (–0·53) (1·95) (5·53)

Surgical techniques

Disposable ports used for single-port laparoscopic procedures included: SILS-Port™ 56·5 per cent (Covidien-Medtronic, Dublin, Ireland); GelPort® 23·4 per cent (Applied Medical, Rancho Santa Margarita, California, USA); OctoPort™ 6·0 per cent (DalimSurgNET, Seoul, Korea); TriPort™ 2·2 per cent and QuadPort™ 0·1 per cent (Advanced Surgical Concepts, Wicklow, Ireland); and S.P.I.D.E.R. 0·1 per cent (TransEnterix®, Research Triangle Park, North Carolina, USA). Alternatively, reusable trocars were employed, namely: Storz X-Cone™ 7·9 per cent (Karl Storz, Tuttlingen, Germany); multiple trocars 3·6 per cent; homemade glove trocar 0·2 per cent; or KeyPort™ 0·1 per cent (Richard Wolf, Knittlingen, Germany). The incision was made routinely at the umbilical groove, except when a protective ileostomy was planned after rectal resection. Three patients (0·2 per cent) had a suprapubic incision via pre-existing scars. Fascial and skin closure was according to the preference of the surgeon. Pre-existing hernias were closed directly without the use of prophylactic mesh. In all procedures extra-long optical devices were used. Surgeons predominantly used straight working instruments (62·2 per cent) followed by curved instruments (37·8 per cent). Suspension devices were used in 160 patients (9·0 per cent) to improve exposure of the surgical field, including sutures in 143 (8·1 per cent), lifting devices in 14 (0·8 per cent) and magnets in three (0·2 per cent). The main indication for use of a suspension device was to place tension on the ileocolic segment in right hemicolectomy (19·1 per cent) or to elevate the uterus or bladder in APR (25·0 per cent) or rectal resection (6·1 per cent). No additional suspension was considered necessary in other procedures (1609, 91·0 per cent). Anastomoses were performed intracorporeally (1304, 73·7 per cent) and extracorporeally (390, 22·0 per cent); 75 patients (4·2 per cent) required no anastomosis. Extracorporeal stapling was the method of choice in right colectomy (73·0 per cent). All other procedures favoured either intracorporeal stapling (left colectomy 98·3 per cent, rectal resection 93·5 per cent, restorative proctocolectomy 92·5 per cent) or no anastomosis (note that 1 anastomosis in the APR group was performed elsewhere in the colon).

Technical results

A total of 1628 procedures (92·0 per cent) were completed without any additional trocar. One, two and three supplementary trocars were used in 121 (6·8 per cent), 17 (1·0 per cent) and three (0·2 per cent) procedures respectively. There was a trend towards use of more trocars in distal procedures with rectal resection (Fig. 1a) and in patients with higher BMI (Fig. 1b). Operating times differed significantly for right colectomy (mean(s.d.) 124(48) min), left colectomy (157(58) min), rectal resection (183(90) min), APR (305(76) min) and restorative proctocolectomy (197(108) min) (P < 0·001) (Fig. S2, supporting information). The duration of operation was prolonged in transrectal retrieval compared with that in the centre-matched cohort of patients undergoing rectal resections via an abdominal retrieval site (239·0(103·7) versus185·1(73·4) min; P = 0·014). In centres performing both types of anastomosis, operating times for right-sided colectomies with intracorporeal and extracorporeal anastomoses were not significantly different (123·0(47·4) versus 133·0(49·7) min; P = 0·057). Specimen retrieval was performed using a wound protector, a retrieval bag, or both, in all patients. Most specimens were removed via the primary incision, including APR (via the perineal incision) (Table 3). In left-sided colectomy and rectal resection, neither operating times nor complications were different between transvaginal and/or transrectal specimen retrieval routes. Predictors for prolonged operation were BMI (P = 0·005, univariable analysis), and ASA grade exceeding I, male sex, distal procedure, conversion, use of non-curved instruments, use of additional trocars and transrectal retrieval site (P < 0·001, multivariable regression analysis).

Correspondence analysis showing procedures (PC, restorative proctocolectomy; APR, abdominoperineal resection; rectal, rectal resection; left, left colectomy; right, right colectomy) in relation to need for additional trocars. b Box plots showing BMI in relation to need for additional trocars. Median value (bold line), interquartile range (box), and range (error bars) excluding outliers (symbols) are shown. P = 0·005 (Kruskal–Wallis test)
Table 3. Specimen retrieval site for single-incision laparoscopic colorectal procedures
Total Right colectomy Left colectomy Rectal resection Abdominoperineal excision Restorative proctocolectomy
(n = 1769) (n = 519) (n = 868) (n = 214) (n = 48) (n = 120)
  1. Values in parentheses are percentages.
Primary incision 1624 (91·8) 515 (99·2) 800 (92·2) 189 (88·3) 0 (0) 120 (100)
Transvaginal 44 (2·5) 3 (0·6) 39 (4·5) 2 (0·9) 0 (0) 0 (0)
Transrectal 41 (2·3) 0 (0) 28 (3·2) 13 (6·1) 0 (0) 0 (0)
Transperineal 48 (2·7) 0 (0) 0 (0) 0 (0) 48 (100) 0 (0)

Conversion

Some 1694 single-port colorectal surgery procedures (95·8 per cent) were completed without conversion. The reasons for conversion were anticipated operative difficulty (pre-emptive, strategic conversions: 68, 91 per cent) or intraoperative complications and technical problems after more than 15 min (reactive conversions: 7, 9 per cent). Conversion rates and independent predictors for conversion are shown in Table 4. BMI differed significantly among patients undergoing procedures with and without conversion (mean(s.d.) 26·0(4·6) versus 28·0(4·9) kg/m2; P < 0·001).

Table 4. Converted procedures and results of multivariable logistic regression analysis to identify independent predictors of conversion
No. of conversions Odds ratio P
  1. Values in parentheses are percentages.
Procedure
Right colectomy 17 (3·3)
Left colectomy 27 (3·1)
Rectal resection 19 (8·9)
Abdominoperineal resection 4 (8)
Restorative proctocolectomy 8 (6·7)
Procedure location
Proximal 44 (3·2) 1·00 (reference)
Distal 31 (8·1) 2·69 < 0·001
Sex
F 23 (2·5) 1·00 (reference)
M 52 (6·1) 2·50 < 0·001
ASA grade
I 5 (1·1) 1·00 (reference)
> I 70 (5·3) 4·89 < 0·001

Complications

Intraoperative complications were observed in 29 patients (1·6 per cent), and included bleeding (13), injury to the urinary tract (7), enterotomy (5) and splenectomy (owing to laceration, 1). In seven of these patients the operation was converted to open surgery. More patients with malignancies had intraoperative complications than those with benign underlying disease (20 versus 9 patients; odds ratio 2·53, P = 0·023). Most of the intraoperative complications were seen in right colonic resections (16 of 29). The use of additional trocars was different in patients with and without intraoperative complications (28 versus 7·6 per cent; odds ratio 4·60, P = 0·001). Interestingly, extracorporeal anastomosis was performed in nearly all patients with complicated right colonic resections (15 of 16 patients).

Postoperative complications were observed in 224 patients (12·7 per cent) (Table 5) and were unrelated to conversion to laparotomy.

Table 5. Complications and results of multivariable logistic regression analysis to identify independent predictors of complications
Postoperative complication SSI Anastomotic leak Odds ratio P
  • Values in parentheses are percentages.
  • *Dindo–Demartines–Clavien classification. SSI, surgical-site infection.
Complication grade*
I 66 (29·5)
II 40 (17·9)
III 73 (32·6)
IV 37 (16·5)
V 8 (3·6)
Procedure 0·008
Right colectomy 68 (13·1) 38 (7·3) 29 (5·6)
Left colectomy 89 (10·3) 5 (0·6) 28 (3·2)
Rectal resection 35 (16·4) 1 (0·5) 5 (2·3)
Abdominoperineal resection 9 (19) 0 (0)
Restorative proctocolectomy 23 (19·2) 2 (1·7) 1 (0·8)
Procedure location
Proximal 157 (11·3) 1·00 (reference)
Distal 67 (17·5) 1·67 0·002
Sex
F 91 (10·0) 1·00 (reference)
M 133 (15·5) 1·66 < 0·001
ASA grade
I–II 167 (11·8) 1·00 (reference)
III–IV 57 (17·2) 1·56 0·006
Disease type
Benign 104 (11·1) 1·00 (reference)
Malignant 120 (14·4) 1·35 0·038

Sex-adjusted risk charts for preoperative prediction of conversion and complication

Based on univariable risk analyses and logistic multivariable regression modelling to determine predicted probabilities for given patients’ profiles (scores), risk charts were developed for the prediction of conversion (Fig. 2) and complication. According to the median and 90 per cent quartile of the predicted probabilities for conversion, patients’ profiles were classified into low, moderate and high risk. Neither age nor malignancy had significant influence on the conversion rate. Thus, the conversion risk chart (Table S1, supporting information) allows preoperative assessment of any possible conversion according to BMI, sex, procedural involvement of the rectum (distal procedures) and ASA grade. Similarly, risk scores were established to classify patients as low, moderate or high complication risk according to a cluster analysis. In particular, male sex, ASA grade III–IV and distal procedures were found independently to result in a higher risk of complications. The complication risk chart (Table S2, supporting information) allows preoperative risk assessment of any possible intraoperative and/or postoperative complication based on the adjusted classification. These scores were validated by enrolment of an additional group of 263 patients who had single-port colorectal surgery.

Violin plots showing conversion risk in relation to a sex, b ASA grade and c procedure location. Median value (symbol), interquartile range (bold line), range (error bars) and kernel density estimate (shaded area) are shown. d Predicted probability of conversion during the single-incision laparoscopic procedure as a function of BMI

Mortality

The overall 30-day mortality rate was 0·5 per cent (8 of 1769), comprising three deaths each following right colectomy and left colectomy, and one death each following rectal resection and restorative proctocolectomy. There were no deaths among patients undergoing APR. The cause of death was surgical in three patients (bleeding 1; multiple organ failure following anastomotic leak in 2 patients on postoperative days 11 and 25 respectively) and medical in five (myocardial infarction 3, pulmonary embolism 1, stroke 1).

Hospital stay

The mean(s.d.) length of hospital stay was 7·8(8·9) days for right colectomy, 8·6(5·4) days for left colectomy, 8·7(6·6) days for rectal resection, 19·0(19·6) days for APR and 10·0(6·7) days for restorative proctocolectomy. Only 54 patients were discharged within 24 h.

Discussion

The broad feasibility and safety profile of the single-port colorectal surgery technique endorses its general applicability. Sex-specific, validated conversion and complication risk charts were compiled to guide patient selection, and to inform decision-making and consent.

Natural-orifice transluminal endoscopic surgery (NOTES) was developed to avoid external incisions and scars altogether, but lacks overall acceptance and experience with colorectal procedures is still sparse[8-10]. Techniques providing natural-orifice specimen extraction via transvaginal or transrectal routes remain valid options[11]. Unlike NOTES, single-port colorectal surgery is a simple modification of conventional laparoscopic surgery that does not require novel instruments or specific new operative strategies, but can be performed by surgeons who are experienced with laparoscopic techniques. Since the first colorectal applications of the single-port colorectal surgery technique were introduced in 2008[4, 5], many clinical series have been published on benign and malignant indications[3, 12-19]. Studies comparing single-port with multiport surgical techniques have demonstrated similar results in terms of complications, blood loss, number of lymph nodes harvested, tumour resection margins, complications and hospital stay[20-23]. Although single-port colorectal surgery is considered more technically demanding, only four early studies[24-27] reported longer operating times for single-port colorectal surgery compared with multiport laparoscopic colorectal procedures. Given that the registry analysis was not designed as a randomized case–control study, the mean(s.d.) operating time of 158(73) min, which includes even the most complex procedures and an array of indications, falls within the mean times reported for single-port and multiport surgery (130–175 min)[22].

Although it was reported that operations can be performed with straight instruments and without the need for special additional equipment[17, 18], interestingly, the use of curved instruments was associated with a significant decrease in operating time in the present study. Possibly the more convenient triangulation led to fewer collisions and allowed a better operative view, thus avoiding repetition of ineffective retraction and dissection. All surgeons used a variety of ports and the present data do not suggest any preference. As expected, longer operating times were associated with higher BMI, use of additional trocars and postoperative complications. The low 30-day mortality rate here is similar to published data (0·5 per cent), demonstrating that mortality after single-port colorectal surgery is mostly related to medical conditions and complications associated with the underlying disease[20-23]. Postoperative complications (in 12·7 per cent of patients) were unrelated to conversion to laparotomy and, unsurprisingly, more frequent in procedures that included pelvic dissection than right or left colectomies. The incidence of anastomotic leakage of 3·7 per cent is comparable to rates of 0·9–6·7 per cent for single-port colorectal surgery reported in smaller series[18, 26, 28]. Although the overall incidence of anastomotic leakage was very low, leakage was associated with death in two patients.

In right colectomies, intracorporeal anastomoses and extracorporeal stapling were associated with similar operating times, but the former resulted in fewer intraoperative complications (in particular bleeding). This might be explained by more traction on the bowel, and more technical difficulty in exteriorizing the specimen through the umbilicus, especially in overweight patients[29]. Buchs and colleagues[30] reported an incidence of 3·6 per cent for anastomotic leakage, and identified rectal location, higher ASA score and prolonged operating times as predictors. However, the low incidence of anastomotic dehiscence for rectal procedures (compared with right or left colonic resections) in the present study could be due to selection bias (patients and/or surgeons). Hirabayashi and co-workers[31] emphasized the importance of surgeon experience in 258 consecutive colorectal cancer procedures.

The rate of wound complications was low (2·5 per cent during short-term follow-up), which is identical to previous data for single-port colorectal surgery[20, 32]. The data are further supported by reports of substantial benefits in wound complication rates in single-port colorectal surgery compared with multiport laparoscopic colorectal procedures in patients undergoing surgery for colorectal cancer (4·3 versus 13 per cent)[28], diverticular disease[33] or complex colorectal surgery[34]. In single-port colorectal surgery the transumbilical access does not necessitate muscle transection, thus reducing the risk of bleeding and subsequent haematoma. This, combined with the wound protection offered by the device itself, may be responsible for the low rate of wound complications in the present series. Data from Japan suggest a 19 per cent lower cost for single-port colorectal surgery in comparison to multiport laparoscopic colorectal surgery using commercial single ports[32]. It is possible that the reduced length of hospital stay[17] and reduction in instrument costs for single-port colorectal surgery may potentially lead to an economic advantage, but this was not addressed in the present investigation. This registry study is limited by its non-randomized design and short follow-up period of 30 days after surgery. The assessment of late complications and overall (oncological) outcomes was not an objective of this study.

The large number of surgeons and participating institutions emphasizes the value of this registry study in representing a real-life scenario and reducing selection bias. Increasing patient numbers and long follow-up are current objectives of the ECSPECT registry to provide continued robust evaluation of single-port colorectal surgery. Finally, only well conducted randomized trials will allow a definite conclusion regarding the technical superiority of single-port colorectal surgery over conventional laparoscopy.

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