Sobhan Mardan-Dezfouli’s MSc Thesis Defence

Title: The Impact of Abdominal Body Contouring Surgery on Physical Function After a Massive Weight Loss: A Pilot Non-Randomized Controlled Trial

Thesis Supervisor: Dr. Cameron Mitchell
Committee Members: Dr. Laura Hurd, Dr. Michael Koehle
Dr. Bill Sheel

Background: It is estimated that 70% of individuals who undergo a massive weight loss (MWL) develop excess skin (ES). The ES around the abdominal area has been shown through patient reported outcome measures to negatively impact perceptions of physical function. Yet no studies have examined the impact of abdominal body contouring surgeries on direct measures of physical function.

Study Objectives: The primary objective of this pilot study was to determine the variability of outcome measures in the context of ceiling, floor and learning effects to allow measuring the test-retest reliability of the physical performance measures. The secondary objectives of this study were to measure recruitment/retention, participant’s acceptability, and adherence to the protocol. The tertiary objective of this study was to provide data to estimate the effect size and sample size required to design a definitive non-randomized controlled trial.

Materials and Methods: Patients who have undergone MWL were recruited through 4 medical clinics and were placed in either body contouring intervention group if they self-selected to undergo surgery or post massive weight loss matched control group. They participated in a series of physical function batteries of tests including 9-item modified physical performance test, 30s-chair to stand, star excursion balance test, timed up and go, modified agility t-test, 6-minute walk test, and body composition measures of fat mass and bone free fat free mass. There was a total of two visits which were 8-12 weeks apart to accommodate for recovery time for abdominal contouring procedures.

Conclusion: It was found that tests involving dynamic balance, agility, and walking were reliable and showed medium to large effect size to be considered for future studies. Retention (72%) and recruitment (46%) rates were found to be compromised due to Covid-19 pandemic local limitations, and institutional surgical regulations. Depending on the primary outcomes of future trials, it is estimated that between 12 to 37 participants are required to be included in the sample size to achieve adequate statistical power.