Comparative Accuracy of Clinical and Formula-Based Estimation of Resection Weight in Reduction Mammoplasty and Implications for Insurance Preapproval and Payment

Abstract

Introduction Insurance companies use minimum resection weight, sometimes based on body surface area (Schnur sliding scale), as a criterion for preapproval and ultimately coverage of reduction mammoplasty. The purpose of this study is to compare the accuracy of subjective resection estimates and estimates calculated by published formulae versus measured resection weights, and to explore the impact of these estimates on insurance preauthorization and payment. Methods A retrospective chart review of bilateral reduction mammaplasties performed at a single academic medical center by seven plastic surgeons from January 2011 to December 2017 was performed. Patients undergoing oncoplastic reduction, simultaneous additional body-contouring procedures, or lacking complete data were excluded. A total of 762 patients were reviewed. Absolute and relative errors between preoperative estimate and actual resection weights were calculated. A subset of patients with requisite breast measurements (n = 579) was examined to compare formula-based with clinical estimates of resection weights. Results Median error was 105 g (14% normalized by resection weight). Frequency of underestimation (40.5%) and overestimation (55.7%) were similar. In 19% (n = 291) of reduced breasts, resection estimate was less than the Schnur requirement. For 5 (2.8%) of these patients, insurers denied coverage explicitly for this reason. Our surgeons' positive predictive value of estimate > Schnur was 86.6%. In 23% (n = 352) of breasts, resection was < Schnur requirement. No insurance claim was denied a posteriori due to resection weight less than Schnur. The formula proposed by Appel et al. produced the most accurate estimates, and is the most likely to produce an estimate < Schnur in nonobese women. Correlations between each surgeon's relative errors and years of faculty experience (r 2 < 0.07) and number of reduced breasts (r 2 = 0.0275) were very weak. Conclusions Resection estimate accuracy varies among surgeons and does not appear to be affected by experience. Because insurers use resection estimates to determine preauthorization, this could be problematic, particularly for surgeons tending to underestimate. However, insurers are inconsistent in application of the Schnur requirement once surgery has been preapproved and its validity as a determinant of medical necessity is in question.

Predicting Breast Reduction Resection Weights and Attainment of Insurance-Mandated Minimums

“…Greater surgeon experience has been proposed to increase the accuracy of resection minimum predictions 17,18 ; however, studies have shown no such correlation. 19 Kung et al found a 73% surgeon positive predictive value for achieving the 500-g minimum. 17 This is similar to our surgeons’ positive predictive values for achieving the 500-g and Schnur minimums, 68% and 71%, respectively; however, this leaves the remaining approximately 30% of women at risk for insurance coverage denial.…”

Preauthorization Inconsistencies Prevail in Reduction Mammaplasty

“…It is well known that preoperative postmenarche symptoms are the biggest predictor of candidacy for reduction mammoplasty. 9 However, there was a wide discrepancy among insurance providers on the number of symptoms required for preauthorization. This ranged from ambiguous descriptions to three or more symptoms being required with a stronger preference for resection weight volume measurements.…”

Breast Resection Weight Prediction and Insurance Reimbursement in Reduction Mammaplasty: Which Scale Is Reliable?

“…This might also explain one of the reasons for its poor predictability of actual resection weight. 6,7,14…”

“…Furthermore, 23 percent of this group had breast resection weights of less than or equal to 500 g, and the Schnur scale overestimated the resection weights in 28.9 percent of the patients. Wampler et al 14 reported that no insurance claim was rejected postoperatively for patients in which the Schnur scale overpredicted the actual resection weight. This could be explained by the different insurance policies and different state and local regulations.…”