Perspectives on surgical randomized controlled trials

Impact of obesity on patients undergoing surgery for rectal cancer in Australia and New Zealand

PURPOSE

Patients with obesity undergoing rectal cancer surgery may have an increased risk of developing complications, though evidence is inconclusive. The aim of this study was to determine the direct impact of obesity on postoperative outcomes using data from a large clinical registry.

METHOD

The Binational Colorectal Cancer Audit registry was used to identify patients who underwent rectal cancer surgery in Australia and New Zealand from 2007-2021. Primary outcomes were inpatient surgical and medical complications. Logistic regression models were developed to describe the association between body-mass index (BMI) and outcomes.

RESULTS

Among 3,708 patients (median age 66 years [IQR 56.75-75], 65.0% male), 2.0% had a BMI < 18.5 kg/m2, 35.4% had a BMI of 18.5-24.9 kg/m2, 37.6% had a BMI of 25.0-29.9 kg/m2, 16.7% had a BMI of 30.0-34.9 kg/m2, and 8.2% had a BMI ≥ 35.0 kg/m2. Surgical complications occurred in 27.7% of patients with a BMI of 18.5-24.9 kg/m2, 26.6% of patients with a BMI of 25.0-29.9 kg/m2 (OR 0.91, 95% CI 0.76-1.10), 28.5% with a BMI of 30.0-34.9 kg/m2 (OR 0.96, 95% CI 0.76-1.21), and 33.2% with a BMI ≥ 35.0 kg/m2 (OR 1.27, 95% CI 0.94-1.71). Modelling BMI as a continuous variable confirmed a J-shaped relationship. The association between BMI and medical complications was more linear.

CONCLUSION

Risk of postoperative complications is increased in patients with obesity undergoing rectal cancer surgery.

The National Aeronautics and Space Administration-task load index: NASA-TLX: evaluation of its use in surgery

BACKGROUND

The technical difficulty an operation creates for a surgeon is difficult to measure. Current measures are poor surrogates. In both research and teaching settings it would be valuable to be able to accurately measure this degree of difficulty. The National Aeronautics and Space Administration Task Load Index (NASA TLX) is a multi-dimensional scale designed to obtain workload estimates relating to a task. This study aimed to evaluate the NASA TLX as an objective measure of technical difficulty of an operation.

METHODS

Seven surgeons performed 127 pre-defined operations (minimally invasive right hemicolectomy & re-do bariatric surgery) and recorded a NASA TLX score after each operation. These scores were compared to numerous clinical parameters and the score was correlated with the subjective measure of whether the surgeon categorized the operation as "easy", "moderate" or "difficult".

RESULTS

The NASA TLX score was significantly correlated with operative duration, blood loss, previous abdominal surgery and the surgeons' assessment of difficulty. It did not correlate with intra-operative or post-operative complications, conversion to open surgery or length of stay.

CONCLUSIONS

The NASA TLX score provides a graded numerical score that that correlated significantly with the surgeon's assessment of the technical difficulty, and with operative duration, intra-operative blood loss and previous abdominal surgery. This novel application of this tool could be employed in both research and teaching settings to score surgical difficulty and monitor a trainee's proficiency over time.