Plastic Surgery Research Council
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PSRC 60th Annual Meeting
Program and Abstracts

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Is there a Safe Lipoaspirate Volume? A Risk Assessment Model of Liposuction Volume as a Function of Body Mass Index Based on TOPS Data
Ian Chow, BA1, Mohammed S. Alghoul, MD1, Nima Khavanin, BS1, Philip J. Hanwright, BA1, Kristen E. Mayer, BS1, Keith M. Hume, MA2, Robert X. Murphy, Jr., MD, MA3, Karol A. Gutowski, MD4, John YS Kim, MD1.
1Northwestern University, Chicago, IL, USA, 2American Society of Plastic Surgery, Chicago, IL, USA, 3Lehigh Valley Health Network, Allentown, PA, USA, 4University of Illinois, Chicago, IL, USA.

PURPOSE: Significant controversy surrounds the maximum permissible lipoaspirate volume. The American Society of Plastic Surgeons (ASPS) safety advisory identifies 5,000 mL as an important metric of safety, recommending that procedures in excess of 5,000 mL take considerable measure to prevent adverse outcomes. However, limited clinical evidence supports this grade D recommendation, and the advisory committee recommends that surgeons formulate a gestalt impression of surgical risk based on preoperative BMI and comorbidity burden. This study represents the first attempt to quantify the comprehensive risk associated with varying liposuction volumes and its interaction with body mass index (BMI).
METHODS: Suction assisted lipectomies were identified in the Tracking Operations and Outcomes for Plastic Surgeons (TOPS) database. To evaluate the validity of current guidelines, outcomes of large volume liposuctions (>5,000 mL total aspirate) and standard volume liposuctions (≤5,000 mL total aspirate) were compared. Next, multivariate regression models were used to assess the impact of liposuction volume on complication rates while adjusting for potential confounding variables. To characterize the dynamic relationship between liposuction volume and BMI, an interaction term for this association was included in the regression models. An interaction term quantifies how changes in the marginal effect of one variable are conditioned by changes in another variable’s value; in this case, how the risk incurred by increasing liposuction volume is affected by changes in BMI.
RESULTS: Of the 11,615 patients meeting inclusion criteria, 542 patients (4.67%) underwent large volume liposuction as defined by current ASPS guidelines. Post-operative complications rates did not differ significantly between the large volume and standard volume cohorts (4.98% vs 4.92%, respectively; p = 0.950). Regression modeling identified liposuction volume (OR 1.143, 95% CI 1.088-1.200, p < 0.001) and BMI (OR 1.088, 95% CI 1.057-1.119, p < 0.001) as significant independent risk factors for complications. However, when examining the effect of these variables simultaneously, increasing BMI exerts a protective effect on the risk associated with a concomitant increases in lipoaspirate volume (OR 0.996, 95% CI 0.995-0.998, p < 0.001). Put simply, a higher BMI reduces the risk associated with increased lipoaspirate volumes. A three-dimensional representation of this effect was constructed with overlying risk curves for theoretical patient examples to demonstrate this relationship visually (Figure 1).
CONCLUSION: The validity of current lipoaspirate volume thresholds was not supported by this analysis. Rater, a dynamic relationship between BMI and lipoaspirate volume was characterized, facilitating a more accurate estimates of individualized risk and obviating the need to resort to absolute safety cutoffs or subjective impressions of risk.


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