Safety and Efficacy of Intraoperative Colonoscopy During Laparoscopic Left-Sided Colorectal Surgery: A Prospective Observational Study

Colorectal cancer (CRC) remains a major global health burden, ranking as the third most commonly diagnosed malignancy and a leading cause of cancer-related mortality [1-3]. Laparoscopic colorectal surgery has transformed CRC management by offering reduced postoperative pain, faster recovery, shorter hospital stays and oncologic outcomes comparable to open surgery. Owing to these advantages, laparoscopic techniques are now widely used across a spectrum of benign and malignant colorectal diseases, including inflammatory bowel disease, diverticulitis, polyps and obstructive lesions [4-6].

Despite these advancements, accurate intraoperative tumour localization continues to pose a significant challenge in minimally invasive surgery. Conventional preoperative modalities, high-resolution colonoscopy, computed tomography (CT) and magnetic resonance imaging (MRI), remain fundamental but are prone to limitations [7-10]. Factors such as incomplete bowel preparation, variable anatomy and small or flat tumour morphology may hinder colonoscopic detection, whereas CT and MRI offer static images that may fail to identify subtle lesions. These shortcomings can result in suboptimal tumour localization and increase the risk of inappropriate or inadequate resection [11,12].

Intraoperative colonoscopy (IOC) has emerged as a useful adjunct to overcome these limitations. By providing real-time mucosal visualization during laparoscopic resection, IOC aids in verifying tumour position, confirming or evaluating tattoo marks and identifying synchronous lesions not evident on imaging or laparoscopy alone [13-15]. Additionally, IOC facilitates intraoperative leak testing, typically via air or dye insufflation, allowing direct assessment of anastomotic integrity [16-18]. Evidence suggests that systematic leak testing can significantly reduce postoperative anastomotic complications [16-18]. Through improved localization and intraoperative verification, IOC may help prevent unnecessary bowel resection and reduce postoperative morbidity.

Given these potential benefits, further evaluation of IOC in laparoscopic colorectal surgery is warranted. Current evidence on its routine use, particularly during laparoscopic colorectal cancer resections, remains limited. Therefore, the present study aims to assess the impact of intraoperative colonoscopy on tumour localization accuracy and intraoperative decision-making in patients undergoing laparoscopic colorectal cancer surgery.

Study Design and Setting

This prospective observational study included consecutive adult patients (≥18 years) with left-sided colorectal tumours who were scheduled for elective laparoscopic resection at our institution between March 2023 and August 2024. All patients provided written informed consent prior to enrolment. Patients with synchronous extra-abdominal disease or contraindications to laparoscopy were excluded.

Preoperative Evaluation

All patients underwent standard preoperative assessment, including diagnostic colonoscopy and contrast-enhanced CT of the abdomen. MRI was performed when clinically indicated. Preoperative imaging and endoscopic findings were documented for comparison with intraoperative assessments.

Surgical Technique and Intraoperative Colonoscopy

Patients were positioned in lithotomy to allow endoscopic access to the colon up to the splenic flexure. After establishing pneumoperitoneum and completing colonic mobilization, intraoperative colonoscopy was performed using a high-definition flexible colonoscope (Olympus CV-170). Under simultaneous laparoscopic visualization, the colonoscope was advanced to the suspected tumour site. IOC was used to:

• Confirm tumour localization
• Inspect any preoperative tattoo marks
• Assess the integrity of the planned or freshly created anastomosis using air or dye leak testing

All IOC findings were recorded. Laparoscopic bowel resection and anastomosis were then completed according to standard surgical principles (Figure 1-10).

Figure 1: Sony Olumpus CV-170 HD system with flexible colonoscope

Figure 2: Descending colon broad based sensile polyp detected on intraoperative colonoscopy

Data Collection

Collected variables included patient demographics, tumour location, findings from preoperative colonoscopy, CT and MRI, as well as intraoperative colonoscopy observations. IOC findings were compared with preoperative localization to determine concordance.

The primary outcomes were accuracy of tumour localization and any resulting change in the surgical plan.

Figure 3: Scope negotiated beyond tumor site/rest of left colon normal

Figure 4: Insertion of flexible colonoscope intraoperative while maintaining patient position and pneumoperitoneum

Figure 5: Intraoperative colonoscopy being done in laparoscopic colorectal surgery flexible colonoscope with torchers and lap working instruments in situ while maintaining pneumoperitoneum

Figure 6: Sigmoid colon circumferential enhancing stenotic thickening (green arrow) (Coronal Plane)

Figure 7: Distal descending colon circumferential enhancing growth (green arrow) (Axial Plane)