Single site laparoscopic colorectal surgery past, present, and future: narrative review

Introduction

Since the development of laparoscopic surgery, newer innovations have occurred such as smaller trocars, surgery without trocars, fewer incisions or single incision laparoscopic surgery (SILS). With the incision commonly being made through the umbilicus or future stoma site, SILS is virtually scarless. The current practice of minimally invasive surgery has been standard laparoscopic surgery (SLS) with multiple ports. While SLS has numerous benefits intraoperatively and postoperatively compared to open surgery, SLS requires multiple incisions throughout the abdomen, causing significant surgical trauma (1-5). SILS reduces the incision to a single spot, consolidating the area of surgical trauma.

SILS was first reported in colorectal surgery by Remzi and Bucher in 2008 (6,7). Since the first case report, colorectal SILS has been slow to implement in common practice due to the unique technical challenges required for its operation. There has been large debate regarding the safety and efficacy of implementing such technology. Fears about compromised oncological outcomes, increase in postoperative complication rate, longer operative times, and numerous other adverse elements have deterred many qualified surgeons.

Various past studies and literature have examined the outcomes and feasibility of SILS in cancer, inflammatory bowel disease (IBD), the obese patient population, and in many other diagnoses. They have examined intra and post-operative complication rates, oncological outcomes, hernia rates, cost, learning curve, and other factors (8-27).

This paper aims to provide a detailed review of the past and present literature on colorectal surgery SILS and provide a comparison to SLS, the standard of minimally invasive surgery. Additionally, this paper highlights future areas of research that can be completed to assess the safety and efficacy of colorectal SILS and its place in modern surgical practice. We present this article in accordance with the Narrative Review reporting checklist (available at https://ales.amegroups.com/article/view/10.21037/ales-24-37/rc).

Methods

Narrative review

This narrative review did not require institutional approval. An electronic database search was conducted on PubMed, Google Scholar, and Harvard Hollis Library. Search terms included: “Single-port”, “single site”, “single-incision” colorectal surgery. Studies were filtered for comparison studies from 2000 to the present in the English language. Additionally, studies were selected from bibliographical review of other studies. Studies were selected for the initial abstract. After the abstract was read, studies were excluded due to lack of a proper control arm, hand assisted SILS, data being out of date range, replicate data, as well as having case report structure. Studies were excluded due to insufficient outcome reporting and lack of specification in field or outcomes. Disagreement was resolved by consensus. Table 1 summarizes the search strategy. Studies were presented in narrative format due to heterogeneity of study type and data. Primary outcomes of interest were operative time, blood loss, conversion to open, insertion of additional trocars, patient length of stay (LOS), intraoperative complications, post-operative complications, postoperative pain, cost charged to the patient, hernia rate, lymph nodes retrieved, disease-free survival, and overall survival. Data included: country, date range of study, number of patients included, study type, study inclusion and exclusion criteria, patient characteristics, patient outcomes, surgical outcomes, primary disease for surgery, and type of surgery.

Meta-analysis

After narrative review, topics of interest were screened for meta-analysis. Topics with sufficient homologous and relevant data were included in the analysis. Retrieved data was analyzed using R version 4.2.2 and library “meta” and “metafor”. Continuous data was pooled using mean difference (MD) with 95% confidence intervals (CIs) and dichotomous data using odds ratio (OR) with 95% CI. The heterogeneity between studies was evaluated using Cochrane’s Q statistics. Primary outcomes with sufficient data were analyzed.

Results

A total of 811 studies were identified from the electronic database search. Thirty-three studies were identified for further inquiry. Eight studies were excluded for lack of a proper control arm, two for replicate data, two for having SILS plus hand assists, and one for being out of the date range. Twenty studies were selected for review including 3,792 patients. Table 2 presents the studies reviewed. Topics ranged from SILS learning curve, cost, cancer, IBD, obesity, postoperative pain, hernias, and robotic SILS. Meta-analysis was completed for cancer and IBD. The primary outcomes analyzed were LOS and operative time.

Experience level

Two studies reported on the SILS surgeon learning curve originating from Japan and the UK.

Tei et al. (8) reported the short and long-term outcomes of SILS between experienced and novice surgeons under the supervision of experienced surgeons. This retrospective study included 344 patients (n=172 in each group) with propensity scores matched between groups. Patients included underwent SILS: segmental colon resection, subtotal colectomy, or rectal resection for stage I–IV colorectal cancer between May 2009 and December 2018. Cases with obstruction or perforation were excluded from the study. The novice group had a longer operative time, lower harvested lymph node count, and lower number of lymph node metastasis. There was no difference between groups in other operative factors, morbidity rates, 3-year disease-free survival rate, and 3-year overall survival rate.

A study published by Sodergren et al. (9) in 2012 examined the learning curve and proficiency of SILS compared to SLS. Additionally, the study examined if prior SLS proficiency affected the learning curve and proficiency of SILS. The study analyzed 36 surgically naive medical students practicing on a lap box trainer. The investigators found a higher overall proficiency in the SLS group compared to the SILS group, however, they found no difference in the learning curves. Interestingly they found no significant difference in the rate of learning between the SILS group with no previous experience and the SILS group that was already proficient in SLS. Even more, the authors found no difference in the learning curve or proficiency amongst those who practiced with articulated instruments compared to those who practiced with straight instruments in SILS.

Cost

Two retrospective studies examined the cost associated with SILS compared to SLS. One study originated from the United States and the other from the Netherlands. All procedures were performed by SILS and SLS surgeons beyond the learning curve.

Stewart et al. (10) reported the final costs charged to 260 patients (n=149 SLS and n=111 SILS) and to the institution from 2008 to 2012. Patients included underwent low anterior resection, abdominoperineal resection, creation of ostomy, total abdominal, total, procto, right, left, or sigmoid colectomy for IBD, cancer or other indications. Using the Consumer Price Index component from the Bureau of Labor, costs were adjusted for inflation according to the 2012 US dollar values. Costs were consolidated into operating room, room and board, diagnostic imaging, pharmacy, laboratory, and miscellaneous expenses. The SLS group was found to have more smokers. There were no other differences in demographics. The investigators found no difference in conversion rate, LOS, creation of ostomy, and rate of readmission. SLS was found to have a longer operative and total operating room time compared to SILS. The authors found no difference in cost between groups. Additionally, they found a decrease in median cost for patients that were readmitted to the hospital after undergoing SILS compared to patients readmitted to the hospital after undergoing SLS.

Similarly, van der Linden et al. (11) reported the financial costs and outcomes of patients undergoing SILS compared to SLS for malignant colon cancer (> stage III). Two hundred and sixty-seven patients (n=78 SILS and n=189 SLS) undergoing elective resection of primary colorectal carcinoma between 2011 and 2012 in the Netherlands were analyzed. The author found a shorter operative time in the SILS group compared to SLS. Investigators found no statistically significant difference in cost to the patient between SILS and SLS.

The literature reviewed showed no difference in cost between SILS and SLS when performed by experienced surgeons.

Cancer

Seven studies reported clinical outcomes of SILS for colorectal cancer. The studies included five retrospective studies and three randomized control trials. Three of the studies originated from South Korea, three from Japan, and one from Italy. All SILS and SLS procedures were performed by experienced surgeons.

Lim et al. (12) reported the short-term surgical outcomes of 307 patients (n=44 SILS and n=263 SLS) in a retrospective study. Patients included underwent elective resection of colorectal adenocarcinoma from 2011 to 2012. Exclusion criteria included large tumor size, unresectable distant solid organ metastasis, operation conducted in an emergent setting, and subtotal colectomy with familial adenomatous polyposis or synchronous multiple colorectal cancers.

The authors found no difference between SILS and SLS in perioperative outcomes, postoperative complications, number of lymph nodes harvested, days to first flatus, and estimated blood loss. It was found there was a longer operative time in the SILS group (168.2 vs. 223.8 minutes, P=0.002). Additionally, ten SILS anterior resections for rectal cancer required additional ports. There were more diverting stomas performed in the SILS group than SLS group (64.7% vs. 24.2% respectively, P=0.01).

Huscher et al. (13) reported the outcomes of 32 patients (n=16 in SILS and SLS) undergoing curative left and right segmental colon resection from 2008 to 2010 in a randomized control trial. Patients were excluded if they had prior abdominal surgery, intra-abdominal sepsis, or distant metastasis. There was no significant difference in demographics between the groups.

Similar to Lim (12) the authors found no difference between the two groups in lymph nodes harvested, blood loss, the extent of resection, time to liquid and solid food intake, and postoperative mortality and morbidity. Additionally, they found no difference between the groups in operative time and there were no conversions to open technique in either group; however, one case in the SILS group required the insertion of an additional trocar.

Lee et al. (14) reported the short-term outcomes of 359 patients (n=179 SILS, n=180 SLS) participating in the SIMPLE randomized control trial from 2011 to 2017. Patients included underwent resection for stage I, II, or III adenocarcinoma of the ascending or sigmoid colon. There was no difference in baseline patient or tumor characteristics.

The investigators found no statistically significant difference in the primary endpoint, 30-day postoperative complication rates. The authors found no difference in operative time, lymph nodes harvested, time to flatus, diet, and rate of intraoperative complications; however, subgroup analysis of the SILS group revealed hemicolectomy was associated with more intraoperative blood loss and postoperative complications than anterior resection. In the SILS group, 25 patients required inserting an additional trocar and three required conversions to open. Conversely, in the SLS group none required conversion to open. The main reason for the insertion of additional ports was adhesions and the inability to create a surgical field or proper angle. Lastly, it was found postoperative pain and analgesic consumption were not reduced with SILS.

Examining the long-term outcomes, Tominaga et al. (15) reported a retrospective propensity-matched analysis of 116 patients (n=58 in SILS and SLS group) who underwent curative resection for right colon cancer. Patients were excluded due to: the procedure being completed in an emergency setting, previous open surgery, or synchronous colon cancer. Propensity score matching was completed based on sex, comorbidities, American Society of Anesthesiologists (ASA) performance status (PS), body mass index (BMI), surgeon experience level, and pathological T/N/M status. The authors found a shorter operative time in the SILS group (172 vs. 193 minutes, P=0.007) along with decreased blood loss (12 vs. 20 mL, P=0.04). Similar to the previous studies mentioned, there was no difference in lymph nodes harvested, length of hospital stay, and postoperative complications. In both groups, no procedure required a conversion to an open approach, and for the SILS group, none required the insertion of an additional trocar. The authors found no difference in the rate of recurrence, three-year disease-free survival, and overall survival. For lymph node-positive patients, the oncological outcomes were the same between groups.

Yun et al. (16) reported a retrospective study of patients undergoing SILS primary radical right colectomy for malignancy. From 2009 to 2010, 159 patients (SILS n=66 and SLS n=93) were analyzed. All procedures were performed at a single center. The authors found no difference in any baseline patient or tumor characteristics. They found a decrease in operative time in the SILS group (155±45 vs. 174±56 min, P=0.02), however, there was no statistically significant difference in procedural time. There was no difference in conversion rate, time to first bowel movement, hospital stay, complication rate, and readmission. The investigators found no difference in postoperative pathology, tumor margins, rates of postoperative adjuvant chemotherapy, follow-up, and recurrence.

Tei et al. (17) presented a retrospective propensity-matched study reporting the oncological outcomes of patients undergoing SILS for rectal cancer. From 2012 to 2015, 204 consecutive patients with stage I–III rectal cancer (n=102 in SILS and SLS group) undergoing primary rectosigmoid or upper rectal resection for rectal cancer were analyzed. After propensity score matching there was no difference in patient or tumor characteristics. The investigators found no statistically significant difference in the rate of stoma creation, blood loss, extent of lymph node dissection, multivisceral resection, or conversion to open, and only 24 cases in the SILS group required an additional port. Operative time in the SILS group was found to be shorter than the SLS group {192 [162–220] and 211 [180–259] minutes respectively, P=0.02}. They found no difference in the rate of postoperative complications [Clavien-Dindo classification (grade ≥2)]. In the SILS group there were less lymph nodes harvested than in the SLS group (24 and 27 nodes respectively, P=0.008). There was no difference in tumor size, histology, proximal margin, distal margin, lymphatic invasion, venous invasion, lymph node metastasis, and pathological TNM stage.

The authors found no difference in three-year local recurrence and three and five-year overall survival.

Lastly, Watanabe et al. (18) reported the long-term outcomes of 200 patients (n=100 in both groups) in a randomized control trial undergoing curative resection of histologically proven stage 0–III colon carcinoma located in the cecum, ascending, sigmoid, or rectosigmoid colon from 2012 to 2015. Exclusion criteria included: multiple cancers, active infectious disease, history of mental disease and/or central nervous system damage, pregnant, lactating, possibly pregnant, severe concomitant disease, history of organ transplantation, preoperative treatment for colorectal cancer, and patients considered inappropriate for enrolment in the trial by the investigators. There was no statistically significant difference in baseline characteristics between the two groups. The investigators found no difference in operative time, tumor diameter, lymph nodes harvested, pathological stage, and rate of adjuvant chemotherapy. In the SILS group, nine cases required the insertion of an additional trocar for rectal transection. There was no difference in five-year relapse-free survival and overall survival between SILS and SLS, however, in subgroup analysis it was found that although not statistically significant, patients with a BMI >25 kg/m² or were clinical stage III had worse survival compared to SLS counterparts. There were no cases of lymph node metastasis or local recurrence in either group.

Meta-analysis heterogeneity variated in the study depending on the variable measured as shown in each outcome figure considering 20–50% I² as moderate heterogeneity. Lack of outcome reporting for was noted for conversion to open, estimated blood loss, intra-abdominal bleeding, ileus, pneumonia, reoperation, wound infection, and other complications. Additionally, there was not enough consistency in reported outcomes to analyze disease free survival. Outcomes with insufficient studies were not reported. Similar to the reported outcomes above, our meta-analysis found the use of SILS in colorectal cancer was associated with a reduced LOS when compared with SLS (MD −1.12; P=0.03) (Figure 1). However, no difference was noticed between interventions regarding operative time (MD −3.64; P=0.82) (Figure 2), intraoperative outcomes, or postoperative complications, including wound infection (OR 1.04; P=0.91), ileus, pneumonia, and other complications. Conversion to laparotomy rate (OR 0.82; P=0.72) and reoperation rate (OR 1.01; P=0.99) were not significant.

Figure 1 Forest plot delineating a decreased length of stay after SILS versus SLS for patients with CRC undergoing colorectal resections. Continuous data were pooled using MD with 95% CI and dichotomous data using OR with 95% CI. The heterogeneity between studies was evaluated using Cochrane’s Q statistics. CI, confidence interval; CRC, colorectal cancer; IV, instrumental variables; MD, mean difference; SILS, single incision laparoscopic surgery; SLS, standard laparoscopic surgery.

Figure 2 Forest plot delineating no difference in operative time between SILS and SLS for patients with CRC undergoing colorectal resections. Continuous data were pooled using MD with 95% CI and dichotomous data using OR with 95% CI. The heterogeneity between studies was evaluated using Cochrane’s Q statistics. CI, confidence interval; CRC, colorectal cancer; IV, instrumental variables; MD, mean difference; SILS, single incision laparoscopic surgery; SLS, standard laparoscopic surgery.

In sum, SILS has been proven to be safe and feasible in colorectal cancer surgery with no change in long term oncological outcomes.

IBD

Four studies examined SILS in IBD. All studies were retrospective, matched, and presented short term outcomes. All surgeries were performed by experienced SILS surgeons. One study involved multiple centers in Europe, one study originated from the Netherlands, one from Germany, and one from the United States.

Firstly, Celentano et al. (19) presented the outcomes of 174 patients (n=58 for SILS, SLS, and open surgery) undergoing ileocecal or redo ileocolic resection for primary and recurrent Crohn’s disease (CD). Patients were excluded if they underwent proctocolectomy, proctectomy, or segmental colectomy. Matching was completed against the presence of perianal disease, recurrent disease, penetrating phenotype of CD, history of previous abdominal surgery, and preoperative medical treatment with steroids and anti-TNF. There was no difference between SILS and SLS groups in the rate of conversion to open and postoperative complications within 30 days of surgery. SILS had a shorter LOS compared to SLS (5 and 7 days respectively). Similar to past findings, the open surgery group demonstrated a worse morbidity profile.

Gardenbroek et al. (20) reported the outcomes of 63 patients (n=21 SILS and n=42 SLS) undergoing ileocolic resection for CD from 2010 to 2012. Patients were case matched for BMI, length of diseased bowel resected, and the presence or absence of internal fistulas. It was found that operative time was significantly shorter in the SILS group compared to the SLS group (103.0 and 123.5 minutes respectively, P=0.04) and the SILS group had a shorter hospital stay (4 and 5 days respectively, P=0.03). There was no conversion to open in either group, and no difference in length of resected bowel, complications, readmission within 30 days, and mortality. Additionally, there was no difference in the postoperative pain scores between groups however, the SILS group required less morphine on the first postoperative day.

Rijcken et al. (21) reported the outcomes of 40 patients (n=20 SILS and SLS) who underwent ileocolic resection for ileocecal CD from 2010 to 2011. Patients were matched for age, sex, and BMI. There was no difference between the groups in immunosuppressive medication, duration of disease, ASA classification, smoking habits, or previous abdominal surgeries. The investigators found the SILS group had a shorter operative time compared to the SLS group (137.4 and 166.4 min respectively, P=0.009). Similar to previous studies, they found no difference in complication rate, hospital stay, and postoperative pain. There was one conversion to open surgery in the SILS group and two conversions in the SLS group due to dense adhesions.

Lastly, Alipouriani et al. (22) reported the outcomes of 456 patients (n=114 SILS and n=342 SLS) who underwent total abdominal colectomy with end ileostomy for medically refractory ulcerative colitis (UC) from 2010 to 2020. There were no differences in baseline characteristics between groups. The investigators found a significantly shorter operative time in the SILS group compared to the SLS group (150.3 and 193.3 minutes, P<0.001). They found no rate difference in postoperative leak, postoperative ileus, stoma site complications, postoperative readmission, postoperative reoperation, and rate of patients in which subsequent ileal pouch-anal anastomosis (IPAA) was performed.

Similar results to the cancer meta-analysis were obtained when comparing SILS and SLS in IBD surgery. However, there was an overall lower heterogeneity <25% for the two outcomes measured that had enough studies reporting it. Significant results included, reduced LOS (MD −0.60; 95% CI: −1.05 to −0.15; P=0.01) (Figure 3) and reduced operative time with (MD −28.73; 95% CI: −45.14 to −12.32; P<0.001) (Figure 4) favoring SILS, supporting what was reported in all previous studies analyzed. Regarding other postoperative complications (OR 1.19; P=0.46) and re-operation rate (OR 0.84; P=0.72) no significant differences were found between groups.

Figure 3 Forest plot delineating a decreased length of stay after SILS versus SLS for patients with IBD undergoing colorectal resections. Continuous data were pooled using MD with 95% CI and dichotomous data using OR with 95% CI. The heterogeneity between studies was evaluated using Cochrane’s Q statistics. CI, confidence interval; CRC, colorectal cancer; IBD, inflammatory bowel disease; IV, instrumental variables; MD, mean difference; SILS, single incision laparoscopic surgery; SLS, standard laparoscopic surgery.

Figure 4 Forest plot delineating a decreased operative time after SILS versus SLS for patients with IBD undergoing colorectal resections. Continuous data were pooled using MD with 95% CI and dichotomous data using OR with 95% CI. The heterogeneity between studies was evaluated using Cochrane’s Q statistics. CI, confidence interval; CRC, colorectal cancer; IBD, inflammatory bowel disease; IV, instrumental variables; MD, mean difference; SILS, single incision laparoscopic surgery; SLS, standard laparoscopic surgery.

Obesity

Two studies reported the outcomes of SILS in patients with BMI ≥30 kg/m². Both were case matched retrospective studies, from the United States, and all cases were performed by experienced SILS and SLS surgeons.

Aytac et al. (23) reported the outcomes of 74 obese patients (n=37 SILS and SLS) who underwent resection for CD, UC, diverticular disease, and cancer from 2009 to 2012. Patients were matched on diagnosis and procedure. Procedures included: proctosigmoidectomy, completion proctocolectomy with IPAA with diverting ileostomy, ileocecectomy, right colectomy, sigmoidoscopy, total colectomy ileorectal anastamosis (IRA), and total colectomy end ileostomy. The patients who underwent SILS were predominantly male. There were no other differences in demographics between groups. There was no difference in operating time, estimated blood loss, time to first flatus, time to first bowel movement, length of hospital stay, reoperation, readmission, overall morbidity, or individual postoperative complications. Additionally, there was no difference in the rate of conversion to open surgery.

Keller et al. (24) reported the outcomes of 80 obese patients (BMI ≥30 kg/m²) matched to 80 non-obese patients who underwent SILS colectomy for diverticulitis, colon cancer, polyp, IBD, and constipation from 2009 to 2014. Procedures included: anterior rectosigmoidectomy, right hemicolectomy, total abdominal colectomy, left colectomy, and transverse colectomy. Patients were matched based on age, gender, diagnosis, and operative procedure performed. Patients in the obese group had a higher ASA score, which is expected due to a higher BMI. There were no other differences in demographics. In the obese group there was a longer operative time and higher estimated blood loss compared to the non-obese group. There was no statistically significant difference in intraoperative complications, intraoperative conversion, final incision length, mean LOS, postoperative complications, reoperation, and readmission. Additionally, for malignant cases there was no difference in the number of lymph nodes harvested and the distal margins were all negative.

Post-operative pain

One study from Hong Kong examined pain as the primary outcome of SILS compared to SLS. A study done by Poon et al. (25) reported the pain outcomes of 50 patients (n=25 in SILS and SLS group) undergoing: right hemicolectomy, left hemicolectomy, sigmoidoscopy, or anterior resection for colon cancer from 2008 to 2010. Postoperative pain score was accessed 15 and 60 minutes after the operation along with postoperative day one, two, three, and 14 at rest and at cough. The median wound pain score at rest was lower in the SILS group throughout postoperative recovery. The postoperative pain score was significantly lower on postoperative day 1 and 2. While lower on all postoperative days, it was found not to be significantly different. The investigators found no difference in patient and tumor characteristics. Between the groups, there was no difference in operative time, blood loss, complication rate, lesion size, proximal margin, distal margin, number of lymph nodes harvested, and total morphine usage. Additionally, there was no mortality, reintervention, or conversion to open in either group.

Hernia

One study from the United States examined hernias in SILS. Sangster et al. (26) reported a retrospective review of the incidence of hernias in patients undergoing SILS for IBD, cancer, and benign causes (i.e., diverticulitis, benign polyps, rectal prolapse). From 2008 to 2013, 276 patients (n=157 SILS and n=119 SLS) who underwent segmental colectomy, total abdominal colectomy, proctectomy, creation of stoma only, and Ladd’s procedure were examined. In all SILS cases the umbilicus or future stoma site was used for trocar placement. The investigators found more patients in the SILS group to have an ASA grade ≥3 [74 (47.1%) patients in the SILS group and 40 (33.6%) patients in the SLS group, P=0.02]. There were no other statistically significant differences in patient characteristics. The author found no difference in the incidence of parastomal hernias, however, found an increase incidence of incisional hernias in the SILS group [n=18 (17.0%) patients in the SILS group and n=9 (7.6%) in the SLS group, P=0.03]. Additionally, the investigators found an increase in the incidence of incarcerated hernias, when hernia was present, in the SLS group [n=2 (6.5%) patients in SILS group and n=7 (38.9%) patients in SLS group, P=0.01]. There was no difference in time to diagnosis of hernia, management of hernia (observation or repair), and median follow-up. It was found that the median time from diagnosis of a hernia to repair was shorter in the SLS group than SILS group (n=0.1 and n=2.3 months respectively, P=0.004). The authors noted that, while not significantly different, hernia rates trended down in the SILS group over time, possibly correlating with the increase in surgeon SILS experience.

Robotic single port (SP)

One study from the United States examined SP robotic surgery. Keller et al. (27) reported a retrospective propensity matched study of the short term and oncological outcomes of cancer patients undergoing SP robotic resection compared to SILS resection. One hundred patients (n=50 SP and SILS) who underwent elective curative resection of a primary adenocarcinoma of the colon or rectum without distant metastasis between 2010 and 2022 were included in the study. Exclusion criteria included: metastatic disease or T4 tumors invading through the anal sphincter complex. Procedures included: right colectomy, left colectomy, trans-anal abdominal trans-anal radical proctosigmoidectomy, and abdominoperineal resection. In procedures with combined abdominal and trans-anal approaches, in the SP group the port was placed trans-analy while in the SILS group the port was placed through the abdomen. All procedures were performed by the same experienced SP surgeon. Patients were matched 1:1 on baseline characteristics. The investigators found a good match of patients; however, it was found in rectal cancer cases, in the SP group, the cancer distance from the resection was significantly lower than the SILS group (1.8 vs. 3.4 cm respectively, P=0.02). The authors found a shorter LOS in the SP group (mean 4.1 vs. 5.3 days, P=0.045). They found no difference in operative time, return of bowel function, and overall postoperative morbidity rate. In all cases there were at least 12 lymph nodes excised, no positive distal margins, no unplanned reoperation, no mortality, and in the rectal cancer cases there were comparable rates of complete total mesorectal excision. Additionally, they found the number of lymph nodes excised, and rate of positive lymph nodes to be the same and there were significantly more additional ports placed in the SILS group than SP group.

Discussion

The emergence of laparoscopic colorectal surgery has ushered in a new era of shorter operative times, decreased postoperative complication rates, and decreased morbidity and mortality. While research has been quick to show the benefits of SLS, SILS compared to SLS has been slow to be assessed in colorectal surgery. In addition to having enhanced cosmetic benefits to the patient over SLS, SILS in other fields of surgery has been shown to reduce operative time, enhance recovery, decrease the hospital stay for the patient, and been proven to be safe and effective (28-31).

This paper aimed to review the past literature on colorectal SILS. This study reviewed 20 papers, included 3,792 patients, and addressed topics ranging from SILS learning curve, cost, cancer, IBD, obesity, postoperative pain, hernias, and robotic SILS.

Case reports early in the learning curve of colorectal SILS have demonstrated higher costs, operative time, skill, and ergonomics to be a barrier to its implementation (32-36). However, the literature reviewed has shown the learning curve of colorectal SILS to be no different to SLS. Interestingly, it was found that the SILS learning curve for someone proficient in SLS is no different than that for a novice SLS surgeon. Many of the skills developed in SLS don’t translate to SILS due to the unique ergonomics of SILS. Many experienced SLS surgeons may be challenged early in the learning curve due to the new skills that must be acquired. Another challenge of SILS is that the level of overall proficiency is suggested to be lower than SLS (9). Difficulty in triangulation and access of the instruments may lead to this lower overall proficiency (14). Further development of ergonomic articulated instruments may allow for better triangulation and access, increasing overall surgeon SILS proficiency.

As well as being safe and effective, the literature reviewed has expressed there to be no difference in cost charged to the patient between colorectal SILS and SLS (10,11). It is important to note that both studies reviewed examine experienced SILS surgeons. While costs may be higher early in the learning curve for novice SILS surgeons, once proficiency is achieved, the burden of cost is expected to be relieved. Future research is needed to shorten the learning curve of SILS and thus lower the initial cost required to adopt this new technique.

Most importantly, despite there being increased technical demand, operative time, and cost in novice SILS surgeons, SILS performed by novice surgeons is suggested to be safe and effective in comparison to SILS performed by experienced surgeons. It was found that in colorectal SILS for cancer resection, there was no difference in long-term disease-free survival between novice and experienced colorectal SILS surgeons when under the supervision of experienced surgeons (8).

Moreover, the studies reviewed on colorectal SILS in cancer have reported comparable safety and efficacy to SLS. This held true for both colon and rectal cancer (12-18). Studies have shown similar long-term oncological outcomes along with survival for both colon and rectal cancer (15-18). These echoed similar findings of SILS in cancer resection in other surgical fields (37-39). Additionally, colorectal SILS in IBD has been shown to have similar short-term outcomes compared to SLS (19-22). Meta-analysis showed no difference in operative time in cancer and a shorter SILS operative time in IBD with a shorter LOS in SILS patients compared to SLS for both groups. Further studies are needed to address the long-term outcomes of SILS in IBD.

While having been proven to be effective in cancer and IBS, SILS has been slow to be implemented in the obese population. However, literature has shown no difference in short term postoperative outcomes for oncological and benign disease (23,24). Further studies are needed to assess the long-term outcomes of colorectal SILS in the obese population.

Studies reviewed on post-operative pain have shown there to be lower reported pain in SILS compared to SLS on all postoperative days and significantly less on day 1 and 2 (25). This is similar to findings in other fields of surgery which have reported less postoperative pain in the SILS group. Only having one singular incision, preventing the Swiss cheese incision pattern, may reduce surgical trauma and thus the inflammatory response after surgery, decreasing pain for the patient. The findings in this study such as a shorter operative time, decreased blood loss, and shorter LOS (15-17,19,20) show SILS to provide an enhanced short-term recovery compared to SLS, however, it appears to have less benefit in the long term outside of the cosmetic benefit to the patient.

Long-term complications such as hernias appear the same between the SILS and SLS groups. The literature reviewed saw no difference in parastomal hernias but an increase in incisional hernias (26). This is thought to be attributed to the longer incision required for the larger trocar that usually accompanies SILS. The author noted hernia rates in the SILS group trended down over time, possibly due to increased experience. Further development of improved tools and training curves may lead to a higher level of proficiency and thus may decrease the incidence of incisional hernias in future colorectal SILS.

Another promising avenue of development in SILS is the implementation of SILS in robotic systems. Robotics has granted surgeons with more versatile surgical site access, decreased operative times, decreased postoperative pain, and enhanced patient recoveries (40). Literature has shown SP to have a shorter LOS and less incidence of insertion of additional ports compared to SILS. Short term outcomes of SP have proven it to be safe and effective compared to SILS (27). Future studies are needed to compare SP with standard multiport robotic surgery.

In SILS rectal resections, studies have demonstrated surgical site access to be one of the difficulties associated with SILS in rectal resections due to the anatomy of the pelvis (12,14,18). However, SP is an effective way to combat this difficulty. The unique angle and ergonomics of the robot allows the user to overcome difficult anatomical structures. Future studies should be completed to examine rectal resections completed with SP.

There were several limitations of this review. Many of the studies reviewed were retrospective and included small sample sizes. Retrospective studies are more likely to be influenced by unaccounted bias and studies with small sample sizes are easily influenced by error which can limit the value of the results. Additionally, many of the studies followed a generalized model with lack of specificity in operation type, region of operation, or proficiency of operating surgeon. These variables may have had a significant effect on the outcomes. The meta-analysis was largely limited by the heterogeneity of the data. Many of the studies lacked outcome reporting and thus only a few variables were able to be analyzed. Lastly, many of the outcomes reported were short term and lacked long term follow up. This limited the scope of the review to SILS in the short term.

Many future directions of SILS will help enhance the capability of minimally invasive laparoscopic surgery. Improving the learning curve and providing a more evidence-based approach will shorten the initial increase in cost and time required to adjust one’s practice. Additionally, the development of tools that allow for easier triangulation, less clashing of instruments, and more user control will allow for a higher level of surgeon proficiency. One of the limitations of this review is that many of the studies examine SILS surgeons beyond the learning curve. Future studies are needed to examine the cost and outcomes for SILS performed by surgeons learning SILS. Additionally, studies are needed to assess the long-term outcomes of colorectal SILS in IBD as well as the long-term postoperative pain and quality of life. Future, studies examining patient reported outcomes of colorectal SILS would provide insight into the patient experience with SILS and further guide clinical decision making. Although colorectal SILS has been shown to have comparable outcomes to SLS, little research has proven long-term SILS superiority over SLS in colorectal surgery. Future studies are needed to examine the long-term benefits of SILS.

Conclusions

This review analyzed 20 studies. When completed by an experienced surgeon, SILS can reduce operative time, inflammation, and postoperative pain for the patient while having safe and effective long-term outcomes compared to SLS. Further studies are needed to examine SILS superiority over SLS and the development of technology in SILS.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://ales.amegroups.com/article/view/10.21037/ales-24-37/rc

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Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://ales.amegroups.com/article/view/10.21037/ales-24-37/coif). The authors have no conflicts of interest to declare.

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References

1. Lacy AM, García-Valdecasas JC, Delgado S, et al. Laparoscopy-assisted colectomy versus open colectomy for treatment of non-metastatic colon cancer: a randomised trial. Lancet 2002;359:2224-9. [PubMed]
2. Lacy AM, García-Valdecasas JC, Piqué JM, et al. Short-term outcome analysis of a randomized study comparing laparoscopic vs open colectomy for colon cancer. Surg Endosc 1995;9:1101-5. [PubMed]
3. Nelson H, Sargent DJClinical Outcomes of Surgical Therapy Study Group. A comparison of laparoscopically assisted and open colectomy for colon cancer. N Engl J Med 2004;350:2050-9. [PubMed]
4. Delaney CP, Kiran RP, Senagore AJ, et al. Case-matched comparison of clinical and financial outcome after laparoscopic or open colorectal surgery. Ann Surg 2003;238:67-72. [PubMed]
5. Kaiser AM, Kang JC, Chan LS, et al. Laparoscopic-assisted vs. open colectomy for colon cancer: a prospective randomized trial. J Laparoendosc Adv Surg Tech A 2004;14:329-34. [PubMed]
6. Remzi FH, Kirat HT, Kaouk JH, et al. Single-port laparoscopy in colorectal surgery. Colorectal Dis 2008;10:823-6. [PubMed]
7. Bucher P, Pugin F, Morel P. Single port access laparoscopic right hemicolectomy. Int J Colorectal Dis 2008;23:1013-6. [Crossref] [PubMed]
8. Tei M, Suzuki Y, Ohtsuka M, et al. Clinical outcomes of single incision laparoscopic surgery for colorectal cancer: A propensity score-matched analysis between well-experienced and novice surgeons. Ann Gastroenterol Surg 2022;7:102-9. [Crossref] [PubMed]
9. Sodergren M, McGregor C, Farne HA, et al. A randomised comparative study evaluating learning curves of novices in a basic single-incision laparoscopic surgery task. J Gastrointest Surg 2013;17:569-75. [Crossref] [PubMed]
10. Stewart DB, Berg A, Messaris E. Single-site laparoscopic colorectal surgery provides similar lengths of hospital stay and similar costs compared with standard laparoscopy: results of a retrospective cohort study. J Gastrointest Surg 2014;18:774-81. [Crossref] [PubMed]
11. van der Linden YT, Govaert JA, Fiocco M, et al. Single center cost analysis of single-port and conventional laparoscopic surgical treatment in colorectal malignant diseases. Int J Colorectal Dis 2017;32:233-9. [Crossref] [PubMed]
12. Lim SW, Kim HR, Kim YJ. Single incision laparoscopic colectomy for colorectal cancer: comparison with conventional laparoscopic colectomy. Ann Surg Treat Res 2014;87:131-8. [Crossref] [PubMed]
13. Huscher CG, Mingoli A, Sgarzini G, et al. Standard laparoscopic versus single-incision laparoscopic colectomy for cancer: early results of a randomized prospective study. Am J Surg 2012;204:115-20. [Crossref] [PubMed]
14. Lee YS, Kim JH, Kim HJ, et al. Short-term Outcomes of Single-port Versus Multiport Laparoscopic Surgery for Colon Cancer: The SIMPLE Multicenter Randomized Clinical Trial. Ann Surg 2021;273:217-23. [Crossref] [PubMed]
15. Tominaga T, Nonaka T, Shiraishi T, et al. Short- and long-term outcomes of single-incision laparoscopic surgery for right colon cancer: A multicenter propensity score-matched analysis. Asian J Endosc Surg 2022;15:547-54. [Crossref] [PubMed]
16. Yun JA, Yun SH, Park YA, et al. Single-incision laparoscopic right colectomy compared with conventional laparoscopy for malignancy: assessment of perioperative and short-term oncologic outcomes. Surg Endosc 2013;27:2122-30. [Crossref] [PubMed]
17. Tei M, Suzuki Y, Ohtsuka M, et al. Comparison of clinical outcomes of single-incision versus multi-port laparoscopic surgery for rectosigmoid or upper rectal cancer. Int J Colorectal Dis 2022;37:1553-60. [Crossref] [PubMed]
18. Watanabe J, Ishibe A, Suwa H, et al. Long-term Outcomes of a Randomized Controlled Trial of Single-incision Versus Multi-port Laparoscopic Colectomy for Colon Cancer. Ann Surg 2021;273:1060-5. [Crossref] [PubMed]
19. Celentano V, Pellino G, Rottoli M, et al. Single-incision laparoscopic surgery (SILS) for the treatment of ileocolonic Crohn's disease: a propensity score-matched analysis. Int J Colorectal Dis 2021;36:605-8. Erratum in: Int J Colorectal Dis 2021;36:609. [Crossref] [PubMed]
20. Gardenbroek TJ, Verlaan T, Tanis PJ, et al. Single-port versus multiport laparoscopic ileocecal resection for Crohn's disease. J Crohns Colitis 2013;7:e443-e448. [Crossref] [PubMed]
21. Rijcken E, Mennigen R, Argyris I, et al. Single-incision laparoscopic surgery for ileocolic resection in Crohn's disease. Dis Colon Rectum 2012;55:140-6. [Crossref] [PubMed]
22. Alipouriani A, Yalamarthi N, Sancheti H, et al. A propensity score-matched analysis of single-port vs multiport laparoscopic total abdominal colectomy with end ileostomy for medically refractory ulcerative colitis. Dis Colon Rectum 2024;67:1139-48. [PubMed]
23. Aytac E, Turina M, Gorgun E, et al. Single-port laparoscopic colorectal resections in obese patients are as safe and effective as conventional laparoscopy. Surg Endosc 2014;28:2884-9. [PubMed]
24. Keller DS, Ibarra S, Flores-Gonzalez JR, et al. Outcomes for single-incision laparoscopic colectomy surgery in obese patients: a case-matched study. Surg Endosc 2016;30:739-44. [PubMed]
25. Poon JT, Cheung CW, Fan JK, et al. Single-incision versus conventional laparoscopic colectomy for colonic neoplasm: a randomized, controlled trial. Surg Endosc 2012;26:2729-34. [Crossref] [PubMed]
26. Sangster W, Kulaylat AN, Stewart DB, et al. Hernia incidence following single-site vs standard laparoscopic colorectal surgery. Colorectal Dis 2015;17:250-6. [Crossref] [PubMed]
27. Keller DS, Reif de Paula T, Ikner TP, et al. Perioperative outcomes for single-port robotic versus single-incision laparoscopic surgery: a comparative analysis in colorectal cancer surgery. Surg Endosc 2024;38:1568-75. [Crossref] [PubMed]
28. Haueter R, Schütz T, Raptis DA, et al. Meta-analysis of single-port versus conventional laparoscopic cholecystectomy comparing body image and cosmesis. Br J Surg 2017;104:1141-59. [Crossref] [PubMed]
29. Arezzo A, Passera R, Bullano A, et al. Multi-port versus single-port cholecystectomy: results of a multi-centre, randomised controlled trial (MUSIC trial). Surg Endosc 2017;31:2872-80. [Crossref] [PubMed]
30. Bucher P, Pugin F, Buchs NC, et al. Randomized clinical trial of laparoendoscopic single-site versus conventional laparoscopic cholecystectomy. Br J Surg 2011;98:1695-702. [Crossref] [PubMed]
31. Saad S, Strassel V, Sauerland S. Randomized clinical trial of single-port, minilaparoscopic and conventional laparoscopic cholecystectomy. Br J Surg 2013;100:339-49. [Crossref] [PubMed]
32. Merchant AM, Cook MW, White BC, et al. Transumbilical Gelport access technique for performing single incision laparoscopic surgery (SILS). J Gastrointest Surg 2009;13:159-62. [Crossref] [PubMed]
33. Gaujoux S, Bretagnol F, Ferron M, et al. Single-incision laparoscopic colonic surgery. Colorectal Dis 2011;13:1066-71. [PubMed]
34. Champagne BJ, Lee EC, Leblanc F, et al. Single-incision vs straight laparoscopic segmental colectomy: a case-controlled study. Dis Colon Rectum 2011;54:183-6. [PubMed]
35. Park JS, Choi GS, Park SY, et al. Randomized clinical trial of robot-assisted versus standard laparoscopic right colectomy. Br J Surg 2012;99:1219-26. [PubMed]
36. Pucher PH, Sodergren MH, Singh P, et al. Have we learned from lessons of the past? A systematic review of training for single incision laparoscopic surgery. Surg Endosc 2013;27:1478-84. [PubMed]
37. Alarcón I, Yang T, Balla A, et al. Single/reduced port surgery vs. conventional laparoscopic gastrectomy: systematic review and meta-analysis. Minim Invasive Ther Allied Technol 2022;31:515-24. [Crossref] [PubMed]
38. Franco A, Pellegrino AA, De Nunzio C, et al. Single-Port Robot-Assisted Radical Prostatectomy: Where Do We Stand? Curr Oncol 2023;30:4301-10. [Crossref] [PubMed]
39. Zhu G, Lang X, Zhou S, et al. Short- and long-term outcomes of single-port versus multiport laparoscopic radical gastrectomy for gastric cancer: a meta-analysis of propensity score-matched studies and randomized controlled trials. BMC Surg 2023;23:223. [Crossref] [PubMed]
40. Ravendran K, Abiola E, Balagumar K, et al. A Review of Robotic Surgery in Colorectal Surgery. Cureus 2023;15:e37337. [PubMed]