Hendrikus J. Pullens

Quality indicators for colonoscopy: Current insights and caveats

Colonoscopy is the diagnostic modality of choice for investigation of symptoms suspected to be related to the colon and for the detection of polyps and colorectal cancer (CRC). Colonoscopy with removal of detected polyps has been shown to reduce the incidence and mortality of subsequent CRC. In many countries, population screening programs for CRC have been initiated, either by selection of patients for colonoscopy with fecal occult blood testing or by offering colonoscopy directly to average-risk individuals. Several endoscopy societies have formulated quality indicators for colonoscopy. These quality indicators are almost always incorporated as process indicators, rather than outcome measures. This review focuses on the quality indicators bowel preparation, cecal intubation rate, withdrawal time, adenoma detection rate, patient comfort, sedation and complication rate, and discusses the scientific evidence supporting them, as well as their potential shortcomings and issues that need to be addressed. For instance, there is still no clear and generally accepted definition of adequate bowel preparation, no robust scientific evidence is available supporting a cecal intubation rate ≥ 90% and the association between withdrawal time and occurrence of interval cancers has not been clarified. Adenoma detection rate is currently the only quality indicator that has been shown to be associated with interval colorectal cancer, but as an indicator it does not differentiate between subjects with one or more adenoma detected.

Colonoscopy with robotic steering and automated lumen centralization: a feasibility study in a colon model.

BACKGROUND AND STUDY AIMS We introduced a new platform for performing colonoscopy with robotic steering and automated lumen centralization (RS-ALC) and evaluated its technical feasibility. PARTICIPANTS AND METHODS Expert endoscopists (n = 8) and endoscopy-naive novices (n = 10) used conventional steering and RS-ALC to perform colonoscopy in a validated colon model with simulated polyps (n = 21). The participants were randomized to which modality they were to use first. End points were the cecal intubation time, number of detected polyps, and subjective evaluation of the platform. RESULTS Novices were able to intubate the cecum faster with RS-ALC (median 8 minutes [min] 56 seconds [s], interquartile range [IQR] 6  min 46  s - 16  min 34  s vs. median 11  min 47  s, IQR 8  min 19  s - 15  min 33  s, P = 0.65), whereas experts were faster with conventional steering (median 2  min 9  s, IQR 1  min 13 s - 7  min 28  s vs. median 13  min 1  s, IQR 5  min 9 s - 16  min 54  s, P = 0.12). Novices detected more polyps with RS-ALC (median 88.1 %, IQR 79.8 % - 95.2 % vs. median 78.6 %, IQR 75.0 % - 91.7 %, P = 0.17), whereas experts detected more polyps with conventional steering (median 80.9 %, IQR 76.2 % - 85.7 % vs. median 69.0 %, IQR 61.0 % - 75.0 %, P = 0.03). Novices were more positive than experts about the new platform (P = 0.02), noting an easier and faster introduction of the colonoscope with RS-ALC than with conventional steering. CONCLUSIONS Colonoscopy with RS-ALC is technically feasible and appears to be easier and more intuitive than conventional steering for endoscopy-naive novices.

Risk of post-colonoscopy colorectal cancer due to incomplete adenoma resection: A nationwide, population-based cohort study:

Background Most post-colonoscopy colorectal cancers (PC-CRCs) are thought to develop from missed or incompletely resected adenomas. Aims We aimed to assess the incidence rate of PC-CRC overall and per colorectal segment, as a proxy for PC-CRC due to incomplete adenoma resection, and to identify adenoma characteristics associated with these PC-CRCs. Methods We performed a nationwide, population-based cohort study, including all patients with a first colorectal adenoma between 2000–2010 in the Dutch Pathology Registry (PALGA). Outcomes were the incidence rate of PC-CRC overall and of PC-CRC in the same colorectal segment, occurring between six months and five years after adenoma resection. A multivariable Cox proportional hazard analysis was performed to identify factors associated with PC-CRCs in the same segment. Results We included 107,744 patients (mean age 63.4 years; 53.6% male). PC-CRC was detected in 1031 patients (0.96%) with an incidence rate of 1.88 per 1000 person years. PC-CRC in the same segment was found in 323 of 133,519 adenomas (0.24%) with an incidence rate of 0.56 per 1000 years of follow-up. High-grade dysplasia (hazard ratio (HR) 2.54, 95% confidence interval (CI) 1.99–3.25) and both villous (HR 2.63, 95% CI 1.79–3.87) and tubulovillous histology (HR 1.80, 95% CI 1.43–2.27) were risk factors for PC-CRC in the same segment. Conclusions Approximately one-third of PC-CRCs are found in the same colorectal segment after adenoma resection and could therefore be a consequence of incomplete adenoma resection, occurring in one in 400 adenomas. The risk of PC-CRC in the same segment is increased in adenomas with high-grade dysplasia or (tubulo)villous histology.

A Real-Time Target Tracking Algorithm forźaźRobotic Flexible Endoscopy Platform

Complex endoscopic interventions require a new generation of devices and instruments. A robotic platform for flexible endoscopy through telemanipulation was developed to meet this demand. The concept of telemanipulation allows the development of software for computer-aided surgery. Intelligent navigation such as automated target centralization could assist the endoscopist during procedures. A real-time algorithm was designed for tracking a target region that is of specific interest for the surgeon. Therefore, the physician needs to indicate the region to be tracked, which then will be centralized (locked). The goal of this research is to investigate the robustness and accuracy of the tracking algorithm during endoscopic interventions. The region of interest can be a polyp for polypectomy, Vater’s ampulla for Endoscopic Retrograde CholangioPancreatography (ERCP), Barrett’s epithelia for gastroscopic biopsy or any area in more complex procedures. The algorithm was tested in vitro on image sequences obtained during real endoscopic interventions. The indicated area of interest could be tracked in all image sequences, with an accuracy of 91.6% (Q1–Q3 77.7%–99.0%, intraclass correlation). The algorithm was robust against instruments or smoke in the field of view. Tracking was less robust against very large camera movements. The developed target lock worked robustly, in real-time and was found to be accurate. Improvements include improving the robustness of the algorithm against motion blur and drift.