Single-Incision Laparoscopic Surgeries for Colorectal Diseases: Early Experiences of a Novel Surgical Method

Objectives. This paper aims to analyze the feasibility and safety of single-incision laparoscopic colectomy (SILC) and its potential benefits. Methods. Systematic review was performed for the years 1983–August 2011 to retrieve all relevant literature. A total of 21 studies with 477 patients undergoing SILC were selected. Results. Range of operative times and estimated blood losses were 75–229 min and 0–100 mL, respectively. Overall conversion rate was 5.9% (28/477) and an additional laparoscopic port was used in 4.9% (16/329) cases. Range of lymph node number for malignant cases was 12–24.6 and surgical margins were all negative. Overall mortality and morbidity rate was 0.4% (2/477) and 11.7% (43/368), respectively. The length of hospital stay (LOS) varied across reports (2.7–9.2 days). Among 6 case-matched studies, one showed less blood loss in SILC as compared to LAC and 2 showed shorter LOS after SILC versus HALC or LAC/HALC groups. In addition, one study reported maximum pain score on postoperative days 1 and 2 was lower in SILS compared to LAC and HALC. Conclusions. SILC procedure is feasible and safe when performed by surgeons highly skilled in laparoscopy. In spite of technical difficulties, there may be potential benefits associated with SILC over LAC/HALC.


Introduction
Recently, laparoscopic surgeries have been widely accepted as a treatment of colon diseases including colon cancer [1][2][3]. Most surgeons are convinced by the short time benefit of the laparoscopic approach in colorectal surgery, that is, early postoperative recovery, decreased postoperative pain, reduced pulmonary dysfunction, and shorter hospitalization [4][5][6]. Moreover, in oncological terms, it has also been shown to be safe in the treatment of colon cancer [1,2]. In order to further improve upon the results of multiport laparoscopic colectomies (LACs), efforts have been made to further reduce the trauma caused by incisions. The rationale for further "scar-less" surgery is that decreasing the number and size of port accesses to the abdominal cavity might be an advantage not only from the cosmetic aspect but also in minimizing the risk of complications such as wound pain and infections as well as incision hernia and internal adhesion formation [7].
The excitement to develop new techniques has given rise to natural orifice transluminal endoscopic surgery (NOTES) [8][9][10]. This procedure in both animal [11] and human [12] models has shown some success but certainly has technical challenges: using transgastric, transvaginal, and transrectal access to the abdominal viscera and the need for expensive specialized equipment has hindered the widespread acceptance of this approach. Therefore use of the NOTES approach in performing routine colon resection is far from being practical at this time. Single-incision laparoscopic surgery (SILS) has advantages over NOTES in that existing laparoscopic instruments can be used and relatively minor adjustments from the current multiport laparoscopic technique are needed. The initial applications of SILS in gastrointestinal surgery were cholecystectomy [13], appendectomy [14] and recently, this technique has also been applied to colorectal surgery [15][16][17][18].
In comparison to multiport laparoscopic colectomy, the potential advantages of SILS are thought to be improved cosmesis as well as incisional and/or parietal pain and avoidance of port site-related complications [40]. Since 2008 when single-incision laparoscopic colectomy (SILC) was first introduced, the number of relevant publications has been increasing year by year as shown in Figure 1. However, because of still limited number of studies reporting SILC [41], its clinical significance remains to be elucidated. The aim of this study is to analyze current literature on SILC and access its potential benefits or efficacy as well as its feasibility and safety.

Literature Search Strategies.
A systematic search of the scientific literature was carried out using the MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials ClinicalTrials.gov (Available at: http://clinicaltrials.gov/), National Research Register, The York (UK) Centre for Reviews, American College of Physicians (ACP) Journal Club, Australian Clinical Trials Registry, relevant online journals, and the Internet for the years 1983-August 2011 to obtain access to all relevant publications, especially randomized controlled trials, systematic reviews, and metaanalyses involving SILC. The search terms were "singleincision," "single port," "single access," "single site," "laparoscopic colectomy," "colectomy," and "laparoscopic colorectal surgery."

Inclusion and Exclusion
Criteria. Articles were selected if the abstract contained data on patients who underwent SILC for colorectal diseases in the form of RCTs and other controlled or comparative studies. Conference abstracts were included if they contained relevant data. The reference lists of these articles were also reviewed to find additional candidate studies. Searches were conducted without language restriction. To avoid duplication of data, articles from the same unit or hospital were included only once if data was updated in a later publication. However, if surgical cases did not overlap among reports by even the same institute, these reports were all included. Reports with fewer than 10 cases of SILC and review articles were excluded from this study. Data extracted for this study were taken from the published reports; authors were not contacted to obtain additional information. All articles selected for full text review were distributed to 2 reviewers (T.M and S.L.), who independently decided on inclusion/exclusion and independently abstracted the study data. Any discrepancies in agreement were resolved by consensus. The flow chart of this selection process is summarized in Figure 2. 2.3. Result of the Literature Research. By using the above search strategy, a total of 249 potentially relevant citations were found. After the exception of 98 duplicated citations, we excluded 86 articles irrelevant of surgical specialty and 37 relevant articles with fewer than 10 cases by reviewing titles and abstracts. 28 publications were selected for review of full text, and 4 studies with no relevant data and 3 review articles were excluded from our paper. Twenty-one studies  with a total of 477 patients undergoing SILC met the criteria for analysis providing level 2-4 evidence ( Table 1). There were one multi-institutional study and a total of 9 comparative studies including 6 case-matched ones between SILC and other minimally invasive procedures. There were no randomized controlled trials and meta-analyses in the selected literature.

Surgical Instruments and Skin Incision Length.
All studies except one [30] used commercially available single port devices as summarized in Table 3. Chen et al. used a surgical glove attached with three trocars for the purpose of reestablishing the pneumoperitoneum after extraction of the specimen and anastomosis [30]. Ross et al., instead of a single access device, used multiple trocars placed through a single skin incision for some patients [32]. All studies, with exception of two [29,34], utilized three ports/trocars (5, 5, 5, or 12 mm) placed through the single access device. Sixteen studies reported on type of laparoscope used [20-26, 29, 30, 32-38]. Most of investigators from the studies reported using 30 • -angled scopes while two studies used 0 • laparoscopes [20,21]. Types of instruments used are detailed in Table 3. The skin incision for the insertion of port systems initially measured 2 to 4 cm, and average length of final scar was 2.7-4.5 cm in 7 studies [22,23,27,[31][32][33]36] with relevant data. The final (at the end of operation) length of incision scar was longer than the initial one in all 11 studies with available data [21-24, 27, 28, 30, 33-36].

Surgical Specimen.
Five studies including right hemicolectomy, sigmoidectomy, and anterior resection showed that the range of specimen lengths was 15-43.5 cm (Table 4) [20,24,27,28,35]. All margins were free of cancer in these series. In 18 studies with available data, the range of number of removed lymph nodes for malignant cases and potential malignant diseases was 12-24.6 (  10) and wound infection/hematoma/seroma (n = 10) followed by and anastomotic bleeding (n = 4) and arrhythmia (n = 3). Overall 6 out of 419 patients (1.4%) required reoperation and the reasons in these cases were as follows: anastomotic leakage (n = 2), anastomotic bleeding (n = 1), wound hematoma (n = 1), cecal ischemia with perforation (n = 1), and a negative relaparotomy to rule out anastomotic leakage (n = 1). In all 21 studies, the range of length of hospital stay (LOS) also varied across reports: 2.7-9.2 days. Notably, 2 studies reported fewer than 3 days of LOS in their series [33,37].   [20] Low anterior resection, and so on.     [20] Lloyd-Davis  Chew et al. [28] (right hemicolectomy)   for the first 2 to 3 days as postoperative anesthesia and no patients required analgesics after the fourth postoperative day [23]. Wolthuis et al. reported that total consumption of levobupivacaine (313 versus 355 mg) and sufentanyl (250 versus 284 µg) provided by epidural infusion with a patientscontrolled bolus capability was similar between SILC and LAC groups (P = 0.94) [24]. Chen et al. also found no difference in the postoperative usage of intravenous narcotics (Demerol) between SILC and LAC groups (10 versus 10 mg, P = 0.82) [30].

Postoperative Recovery of Gastrointestinal Function.
Several reports [21,23,26,29,30,37,39] provided data regarding postoperative recovery of gastrointestinal function; Gash et al. [37], in their analysis of 20 SILC procedures, reported that a normal diet was tolerated in 4-6 hours by 7 patients and in [12][13][14][15][16] [22,24,27,31,33,36] between SILC and other minimally invasive procedures are summarized in Tables 5 and 6. Ramos-Valadez et al., in their case-matched series (SILC versus LAC group), reported that mean estimated blood loss was significantly lower for the SILC group (n = 20) compared to the LAC group (n = 20) (58 versus 99 mL, P < 0.007) [22]. Champagne et al., in their case-controlled study comparing SILC (n = 29) versus laparoscopic-assisted (n = 29) segmental colectomy, reported that SILC is feasible and safe but takes longer time in surgery (134 versus 104 min P = 0.0002) [27]. There were no short-term outcome benefits associated with SILC. Chen et al. also did not find any significant benefits associated with right hemicolectomy by SILS approach compared to the same procedure by the multiport laparoscopic approach [30].  [33]. Importantly, average LOS was significantly shorter in the SILC group compared with the HALC group (2.7 versus 3.3 days P < 0.02), which was also supported by another

Discussion
Potential advantages of SILC over other minimally invasive surgeries include a single small skin incision. The length of the skin incision is partly determined by the size of the resected specimen. Extraction difficulties may be encountered with large colon tumors or with obese patients with thick mesentery, omentum, or deep abdominal wall and colon filled with stool. In fact, our paper revealed that the final (at the end of operation) length of incision scar was longer than the initial one in all relevant reports, suggesting that cosmetic analysis on SILC should be based on final, not initial, scar length and objectively based on cosmesis scale or body image scale which has not yet been examined in any literature. In theory, a single midline fascial incision may minimizes trauma to the abdominal muscles, epigastric articles, and parietal nerves made by multiple trocars in LAC cases. This potentially leads to less postoperative pain and long-term additional port site complications; one out of two case-matched studies demonstrated significantly less postoperative pain score in SILC group as compared to LAC and HALS groups although another study failed to show less postoperative use of anesthesia in SILC group. When introducing any new technology, one significant limitation is often the cost of the procedure. Generally, the initial increases in operative costs associated with laparoscopic techniques are mitigated by reduction in morbidity and duration of hospital stay as a result of the minimally invasive surgery. In fact, several studies which examined both short-term and long-term costs associated with laparoscopic colectomy showed an initial increase in the cost associated with laparoscopic colectomy but a longterm, overall saving. The potential challenge with SILC is that it will require purchase of proprietary instrumentation and additional equipments in some cases which increase overall operative cost. Although potential benefits including fewer conversions, a shorter postoperative recovery or LOS, and less morbidity would make SILC more cost effective, demonstration of any economic benefit over LAC can be difficult. Waters et al. [35] reported that the port itself was purchased at a cost of 550-650 USD compared with average cost of 80 USD of the ports used in the standard LAC cases. The marginal increase in direct operative cost was 310-410 USD per case. With similar operative time and LOS, it can be inferred that the total increase in cost is only that of the port device itself.
Concerning surgical instruments and techniques, SILS has several disadvantages compared with multiport laparoscopic surgery. Standard laparoscopic surgeries are performed through multiports allowing variation of scope placement and angling when met with obstructions. In SILS, no additional ports exist for placement of the scope and maneuvering is greatly restricted by nearby instruments. Therefore SILS requires an experienced surgeon to overcome the difficulties of triangulation, pneumoperitoneum leaks, and instrument crowding. In fact, according to our paper, as many as 9 cases needed to be converted to either open or multiports laparoscopic procedure to get better retraction or aid in colonic mobilization. Some investigators recommend utilizing articulating instruments or since obesity was found to be a common reason for conversion, variable length tools including a bariatric-length bowel grasper or an extralong laparoscope to minimize external clashing are also recommended [19,30]. One of the most challenging factors for SILC in attaining widespread use is the additional learning curve required for this technique. The SILC is essentially a one-operating surgeon technique which has a potentially detrimental impact upon resident education, affecting the training of future surgeons as well. Because most surgeons are still performing open colectomy (the prevalence of even standard LAC procedure is still under 25% in the US [44,45]) or are on their own learning curve for laparoscopy, it requires further analysis to determine the impact that introducing a more technically demanding procedure has on training these surgeons.

Conclusions
SILC is a challenging procedure but seems to be feasible and safe when performed by surgeons highly skilled in laparoscopy. SILC may have potential benefits over other types of minimally invasive surgeries (LAC or HALC), however this has not yet been objectively shown. In the future, randomized controlled trials with a large number of cases are necessary to determine the role of SILC in cost benefit, cosmetic, and oncologic outcomes.