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Study examines POEM learning curve

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Sophisticated measurement technique evaluates individual learning curves

Determining competency in endoscopic procedures has been a vexing challenge since the introduction of flexible endoscopy. Traditionally, procedure volume has been used as a surrogate for technical competence. However, each endoscopist has their own learning curve. Furthermore, that curve is influenced by both the endoscopist and the characteristics of each patient. Thus, relying on procedure volume or length of time are likely inadequate markers of the true learning process. It has become more important to rely on more sophisticated measurements of competence, as illustrated in this study by Liu et al.

By using a large database of patients undergoing POEM, the authors applied risk-adjusted cumulative sum and moving averages (CUSUM) analysis to develop individual learning curves of six training endoscopists. The primary outcomes used to develop the curve were technical failure and adverse effects (likely the two outcomes patients are most concerned about). The analysis was adjusted for case complexity as well, reflecting that not all training episodes are the same. The results reveal that, although trainee endoscopists were able to perform POEM “quickly” by 70 cases, they did not achieve the more important primary outcomes of technical success and low adverse events until at least 100 procedures. This is akin to the difference between getting to the cecum quickly and having a high adenoma detection rate in colonoscopy.

Moving forward, using sophisticated measurement of individual endoscopists’ learning curves will allow maximal effectiveness of routine procedures such as colonoscopy.

Kal Patel, MD, is associate professor of medicine, Baylor College of Medicine, Houston. He has no conflicts of interest.



Technical failures or adverse events complicated 4% of peroral endoscopic myotomies (POEMs) in a large single-center retrospective study.

Individual predictors of this composite negative outcome included case number, full-thickness myotomy, and procedure time, Zuqiang Liu, PhD, and his associates at Fudan University, Shanghai, China, wrote in the September issue of Clinical Gastroenterology and Hepatology.

After controlling for these risk factors, the composite rate of adverse events and technical failures dropped gradually after an endoscopist had performed his or her first 100 cases, according to the researchers. “Technical proficiency, demonstrated by plateauing of the procedure time, could be achieved after 70 cases,” they wrote. “The volume of cases required to manage challenging situations and prevent adverse events was thus higher than that needed for simple technical proficiency.” The experience of the training surgeon helped trainees gain technical proficiency faster, they added.

Peroral endoscopic myotomy (POEM) is minimally invasive and effectively treats spastic esophageal motility disorders. However, it is also a challenging procedure, and little is known about its learning curve. For the study, the researchers retrospectively reviewed technical failures and adverse events among 1,346 POEMs performed for achalasia at a single hospital in China between August 2010 and July 2015. They also assessed procedure time and a secondary composite outcome consisting of technical failure, adverse events, and clinical failure (further symptoms) for the first 192 cases performed by the original training surgeon.

There were 10 technical failures and 44 adverse events affecting a total of 54 patients (4%). Case number (P = .010), full-thickness myotomy (P = .002), and procedure time (P = .001) independently predicted this primary composite outcome. Adjusted cumulative sum analysis showed that the rate of this composite outcome decreased gradually after a surgeon had performed his or her first 100 cases. “The procedure time was high during the first few cases and decreased after endoscopists performed 70 cases,” indicating technical proficiency, the investigators wrote. The rate of the secondary composite outcome also fell gradually after the primary surgeon had performed between 90 and 100 cases.

For the first 192 cases performed by the lead surgeon, postprocedural follow-up time was typically 59 months, with a range of 3-71 months. Clinical failures occurred in 20 cases (10%). Rates of clinical failure were 6% at 1 year, 8% at 2 years, and 10% at 3 years.

This is the first study and the largest POEM database so far to assess the learning curve for this procedure by evaluating adverse events and clinical and technical failure, said the researchers. Previous studies consisted of small cases, usually of less than 100 patients each, they added. Such studies would inherently be biased because the smaller the caseload, the longer it might take for the learning curves of surgeons to plateau, they added.

Funders included the National Natural Science Foundation of China, the Major Project of Shanghai Municipal Science and Technology Committee, the Chen Guang Program of Shanghai Municipal Education Commission, and the Outstanding Young Doctor Training Project of Shanghai Municipal Commission of Health and Family Planning. The investigators reported having no relevant conflicts of interest.

SOURCE: Zuqiang L et al. Clin Gastroenterol Hepatol. 2017 Dec 5. doi: 10.1016/j.cgh.2017.11.048.

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