Although single-incision laparoscopic surgery (SILS) has gained some attention as a feasible alternative to conventional multiport laparoscopic surgery (MPLS) in colonic surgery, it became less prevalent than expected. Hence, we conducted this systematic review to evaluate the feasibility, safety, and oncological outcomes of single-incision laparoscopic colectomy (SILC) with meta-analysis and discussion of the future prospect of SILS. The search was conducted from September to October 2023 using PubMed and the Cochrane Central Register of Controlled Trials. Articles on colorectal cancer comparing SILC with multiport laparoscopic colectomy (MPLC) from all randomized controlled trials and comparative studies with 50 patients or more per arm were examined. The primary outcomes were the intra- and postoperative complication rates, and the secondary outcomes were the perioperative and oncological outcomes. The trends of the SILS number in Japan and the trends of the number of articles on SILS in PubMed were also reviewed. There were no significant differences in perioperative complication rates, operative factors, and oncological outcomes between SILC and MPLC, although heterogeneity was observed mainly in operative factors and the total length of the skin incision was significantly shorter in SILC. Therefore, SILC is technically and oncologically feasible and safe when performed by experienced laparoscopic surgeons. The case number of SILS was gradually increasing but the rate of SILS was decreasing in Japan. The number of articles on SILS was also decreasing. SILS has gained foothold to some extent but has plateaued. The emerging new robotic platform may reappraise the concept of SILS.

Objectives: Detailed superiority of CAD EYE (Fujifilm, Tokyo, Japan), an artificial intelligence for polyp detection/diagnosis, compared to endoscopists is not well examined. We examined endoscopist's ability using movie sets of colorectal lesions which were detected and diagnosed by CAD EYE accurately.

Methods: Consecutive lesions of ≤10 mm were examined live by CAD EYE from March-June 2022 in our institution. Short unique movie sets of each lesion with and without CAD EYE were recorded simultaneously using two recorders for detection under white light imaging (WLI) and linked color imaging (LCI) and diagnosis under blue laser/light imaging (BLI). Excluding inappropriate movies, 100 lesions detected and diagnosed with CAD EYE accurately were evaluated. Movies without CAD EYE were evaluated first by three trainees and three experts. Subsequently, movies with CAD EYE were examined. The rates of accurate detection and diagnosis were evaluated for both movie sets.

Results: Among 100 lesions (mean size: 4.7±2.6 mm; 67 neoplastic/33 hyperplastic), mean accurate detection rates of movies without or with CAD EYE were 78.7%/96.7% under WLI (p<0.01) and 91.3%/97.3% under LCI (p<0.01) for trainees and 85.3%/99.0% under WLI (p<0.01) and 92.6%/99.3% under LCI (p<0.01) for experts. Mean accurate diagnosis rates of movies without or with CAD EYE for BLI were 85.3%/100% for trainees (p<0.01) and 92.3%/100% for experts (p<0.01), respectively. The significant risk factors of not-detected lesions for trainees were right-sided, hyperplastic, not-reddish, in the corner, halation, and inadequate bowel preparation.

Conclusions: Unique movie sets with and without CAD EYE could suggest it's efficacy for lesion detection/diagnosis.

Objectives: Surgical-site infections (SSIs) are the most common complication after stoma closure. We propose a new method for wound closure using the subcutaneous large-bite buried suture (SLBS) technique and a closed suction drain (CSD). In this study, we aimed to investigate the efficacy of a combination of the SLBS technique and a CSD to prevent superficial SSIs following stoma closure.

Methods: We retrospectively analyzed patients who underwent stoma closure between January 2019 and July 2022. Primary closure of the stomal site was performed using the SLBS technique and a CSD for wound closure. The CSD was placed until postoperative day 7. The occurrence of superficial postoperative SSIs was also evaluated.

Results: In total, 67 patients were included in the study. Within 30 days postoperatively, nine patients (13%) developed superficial SSIs. Considering the type of stoma, only 1 (2%) of 45 patients with ileostomy showed superficial SSIs, whereas 8 (36%) of 22 patients with colostomy showed superficial SSIs. Univariate analysis of the risk factors associated with the occurrence of superficial SSIs revealed that colostomy (p < 0.001) and hand-sewn anastomosis were significant risk factors (p = 0.019). Multivariate analysis of the risk factors associated with the occurrence of superficial SSIs revealed that colostomy was significant risk factor (p = 0.003).

Conclusions: This new method of stoma closure is feasible for preventing superficial SSIs, especially in ileostomy closure.

Objectives: Parastomal hernia (PSH) is a common complication of colostomy; however, its risk factors remain poorly investigated. In this study, we examined the associations between sarcopenia, visceral and subcutaneous fat, and PSH in patients who underwent transperitoneal colostomy for colorectal cancer.

Methods: This retrospective, single-center, cohort study included 60 patients who underwent laparoscopic or robot-assisted abdominoperineal resection or Hartmann's procedure for colorectal cancer between November 2010 and February 2022. Stoma creation was uniformly performed using the transperitoneal approach, and PSH was diagnosed via abdominal computed tomography (CT) at 1 year postoperatively. Visceral fat areas (VFAs) and subcutaneous fat areas (SFAs) were measured through preoperative CT images using an image analysis system. Risk factors for PSH were retrospectively analyzed.

Results: PSH was diagnosed in 13 (21.7%) patients. In the univariate analysis, PSH was significantly associated with body mass index >22.3 kg/m² (p=0.002), operation time >319 min (p=0.027), estimated blood loss >230 mL (p=0.008), postoperative complications (p=0.028), stoma diameter >18.6 mm (p=0.015), VFA >89.2 cm² (p=0.005), and SFA >173.2 cm² (p=0.001). Multivariate analyses confirmed that SFA >173.2 cm² (odds ratio: 16.7, 95% confidence interval 1.29-217.2, p=0.031) was an independent risk factor for PSH.

Conclusions: Subcutaneous fat area is significantly associated with the development of PSH after transperitoneal colostomy. Applying these insights could help to prevent PSH.

Objectives: To investigate patient acceptance and preference for computed tomographic colonography (CTC) over colonoscopy.

Methods: Participants were recruited from a nationwide multicenter trial in Japan to assess the accuracy of CTC detection. They were scheduled to undergo colonoscopy after CTC with common bowel preparation on the same day. Some were administered sedative drugs during colonoscopy, depending on the referring clinician and participant's preferences. The participants were requested to complete a questionnaire to evaluate the acceptability of bowel preparation, examinations, and preference for future examinations.

Results: Of the 1,257 enrolled participants, 1,180 (mean age: 60.6 years; women: 43.3%) completed the questionnaire. Sedative drugs were not administered in 687 participants (unsedated colonoscopy group) and were administered intravenously during colonoscopy in 493 participants (sedated colonoscopy group). Before propensity score matching, the mean participants' age, percentages of asymptomatic participants, insufflation of gas during colonoscopy, and number of participants with a history of abdominal/pelvic operation significantly differed between the groups. After propensity score matching, 912 participants from each group were included in the analysis. In the unsedated colonoscopy group, CTC was answered as significantly easier than colonoscopy (p<0.001). Conversely, CTC was significantly more difficult than colonoscopy in the sedated colonoscopy group (p<0.001). In the unsedated colonoscopy group, 48% preferred CTC and 22% preferred colonoscopy for future examinations, whereas in the sedated colonoscopy group, 26% preferred CTC and 38% preferred colonoscopy (p<0.001).

Conclusions: CTC has superior participant acceptability compared with unsedated colonoscopy. However, our study did not observe the advantages of CTC acceptance over sedative colonoscopy.

Objectives: Deep pelvic abscesses are surrounded by the pelvic bones, bladder, gynecological organs, intestinal tract, and nerve and vascular systems, and are approached by various routes for drainage. The transgluteal approach is often performed under computed tomography guidance; however, if ultrasonography can be used to confirm the approach, it is considered more effective because it reduces radiation exposure and allows for real-time puncture under sonographic and fluoroscopic guidance.

Methods: This retrospective study was conducted at Tobata Kyoritsu Hospital (Fukuoka, Japan) between April 1, 2021, and December 31, 2022. Sonographically guided transgluteal drainage with fluoroscopy was performed in five consecutive cases of deep pelvic abscesses using a 3D image analysis system (SYNAPSE VINCENT) to study the anatomy for safe puncture.

Results: Three patients had postoperative abscesses from colorectal cancer, one caused by perforation of the appendicitis, and one caused by sigmoid diverticulitis. The average drainage duration was 11 days (SD = 6.7). No complications, such as bleeding or nerve damage, were observed.

Conclusions: We constructed a 3D image of the puncture route of the trans greater sciatic foramen using SYNAPSE VINCENT to objectively comprehend the anatomy and puncture route. The ideal transgluteal approach is to insert the catheter as close to the sacrum as possible at the level of the infrapiriformis. The parasacrum infrapiriformis approach can be performed safely and easily using ultrasound guidance and fluoroscopy.

Objectives: A total mesenteric excision (TME) with lateral pelvic lymph node dissection (LLND) is the standard treatment for advanced low rectal cancer in Japan. Recently, neoadjuvant (chemo) radiotherapy (n (C) RT) has been used with LLND to improve outcomes at multiple Japanese institutes. This study evaluates the benefits of adding nCRT to TME with LLND.

Methods: Seventy-two consecutive patients who underwent TME and LLND with or without nCRT between 2006-2019 to treat advanced low rectal cancer were retrospectively reviewed. The clinicopathological data were compared and the risk factors for local recurrence were evaluated.

Results: Fifty-seven patients (79.1%) underwent TME and LLND with nCRT, and 15 patients (20.9%) without nCRT. There was no significant difference in the clinicopathological characteristics except the clinical T stage. The occurrence of postoperative complications was statistically insignificant. The 5-year local recurrence rate of patients with nCRT was significantly lower than those without (4.0% versus 26.6%, in all patients, p=0.002). Multivariate analysis revealed that the absence of nCRT was an independent risk factor for local recurrences in patients who underwent TME with LLND (hazard ratio: 6.04, p=0.04).

Conclusions: The administration of nCRT prevented local recurrences more effectively in patients with advanced low rectal cancer who underwent TME with LLND.

Objectives: Lateral internal sphincterotomy is a conventional surgical intervention for chronic anal fissures, yet the potential for postoperative anal incontinence underscores the need for an alternative approach. This study aimed to evaluate the outcomes of patients with chronic fissures who underwent a combination of fissurectomy, vertical non-full thickness midline sphincterotomy (VNMS), and mucosal advancement flap (MAF), as a means of mitigating the risk of incontinence.

Methods: This retrospective analysis included forty-six consecutive patients with chronic anal fissures, unresponsive to topical diltiazem, who underwent fissurectomy combined with VNMS and MAF between April 2018 and May 2023. Primary outcome measures encompassed fissure healing rates. Continence was assessed using the Fecal Incontinence Severity Index (FISI), and manometric assessments were conducted before the procedure and three months postoperatively.

Results: With a median follow-up of 27 months, there were no postoperative complications, and the overall fissure healing rate reached 96% (44/46). At three months post-procedure, FISI scores were reduced to 0, with no instances of fecal soiling. Anal resting pressure exhibited a significant reduction at 3 months [pre-op: 133 (95% CI, 128−150) vs. 3 mo: 109 (95% CI, 100−117) cmH₂O; p = 0.01]. Similarly, maximum anal squeeze pressure showed a significant decrease three months post-surgery [pre-op: 317 cmH₂O (95% CI, 294−380) vs. 3 mo: 291 cmH₂O (95% CI, 276−359), p = 0.03].

Conclusions: The combination of fissurectomy, VNMS, and MAF proved to be an effective approach for chronic anal fissures, yielding favorable medium-term outcomes without postoperative anal incontinence.

Objectives: Colorectal perforation is associated with high morbidity and mortality rates after surgery. We investigated various clinical features of patients who underwent emergency surgery for colorectal perforation and explored the risk factors for postoperative complications and hospital mortality.

Methods: Data from 147 patients who underwent surgery for colorectal perforation were retrospectively reviewed. We investigated various clinical and operative factors, including inflammation-based prognostic scores (IBPSs), and evaluated the risk factors for postoperative complications and hospital mortality due to colorectal perforation.

Results: Among 147 patients, the most frequent postoperative complication was wound infection (32 cases, 21.8%), followed by intra-abdominal abscesses (27 cases, 18.4%) after surgery for colorectal perforation. Time from onset to surgery ≥ 2 days (Hazard ratio [HR] = 2.810, p = 0.0383) and prognostic nutritional index (PNI) < 30 (HR = 3.190, p = 0.0488) were identified as risk factors for intra-abdominal abscess, while neutrophil-lymphocyte ratio (NLR) < 6.15 (HR = 5.020, p = 0.0009) was identified as a risk factor for wound infection. Time from onset to surgery ≥ 2 days (HR = 7.713, p = 0.0492), severe postoperative complications (Clavien-Dindo grade ≥ IIIa) (HR = 10.98, p = 0.0281), and platelet-lymphocyte ratio (PLR) < 144 (HR = 18.84, p = 0.0190) were independent predictive factors for hospital mortality.

Conclusions: Time from onset to surgery and IBPSs such as PNI, NLR, and PLR, may be associated with postoperative complications and hospital mortality due to colorectal perforation.

Objectives: Chronic constipation is a common gastrointestinal disorder, and management is crucial. Computed tomography (CT) is useful for evaluating rectal fecal mass but limited owing to radiation exposure, cost, and inaccessibility at certain facilities. Ultrasonography (US) avoids these pitfalls, but it is unknown whether it accurately assesses rectal feces. In this study, we evaluated the diagnostic performance of US compared with CT as the gold standard for assessing rectal feces.

Methods: We prospectively evaluated rectal fecal mass retention using US performed within 1 h of CT to assess the degree of agreement between methodologies. Rectal stool findings were evaluated on three levels: no stool (R1), presence of stool (R2), and hard stool filling (R3).

Results: The sample included 100 patients (55 men, 45 women), of whom 47 were constipated. The kappa coefficients for rectal content detection were excellent between US and CT (p <0.001). Eighty-two cases (R1: 46 cases; R2: 28 cases; R3: 8 cases) were matched with CT and US findings, and 18 were not. Cases that did not match had low urine or high gas volumes. CT and US findings showed high agreement in constipation (kappa coefficient 0.674, p <0.001) and non-constipation groups (kappa coefficient 0.677, p <0.001). All cases with R3 on CT were found in the constipation group, while more than half of the cases with R1 on CT were in the non-constipation group.

Conclusions: CT and US showed high agreement in evaluating rectal fecal mass retention, indicating that US can substitute CT.

Background: Spatial and temporal heterogeneities of RAS and other molecular genes should be considered in the treatment of metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs); acquired RAS mutation is sometimes observed at disease progression of treatment with the anti-EGFR mAb. At the same time, discrepancy of RAS status from tissues and circulating tumor DNA (ctDNA) in the same patient is sometimes observed. Based on this, we commenced two observational studies to clarify these heterogeneities of RAS and BRAF in mCRC, using next generation sequencing from liquid biopsy.

Methods/Design: RAS-trace study is an observational study to monitor ctDNA RAS/BRAF/PIK3CA status every 4-12 weeks using the Plasma-SeqSensei™ CRC RUO Kit (Sysmex Inostics GmbH) in mCRC with RAS/BRAF wild-type (wt) on tumor tissue. The primary endpoint was the time to the acquired RAS mutations. A total of 42 patients has been accrued. RAS-trace-2 study is also an observational study aimed at comparing the efficacy of the anti-EGFR mAb in ctDNA RAS/BRAF wt with ctDNA RAS or BRAF mutant mCRC patients, whose RAS/BRAF are wt in tumor tissue. The primary endpoint was progression-free survival in patients with ctDNA RAS/BRAF wt and RAS or BRAF mutant. A total of 240 patients will be accrued over 2 years.

Discussion: These trials will help us understanding the clinical significance of spatial and temporal heterogeneities of RAS, BRAF and other genes, while optimizing the anti-EGFR mAb treatment strategies in mCRC.