Factors Affecting Total Operating Time in Patients Undergoing Mastectomy With and Without Reconstruction.

ABSTRACT

BACKGROUND: Operating room (OR) time varies significantly in patients undergoing mastectomy. We sought to determine factors influencing OR time such that more accurate predictions could be made. METHODS: Records of patients undergoing mastectomy at our institution between January 2010 and June 2018 were reviewed. Operating Room time was defined as time from incision to dressing. Nonparametric analyses were performed to determine factors associated with OR time. A predictive model using linear regression was created on a training set and evaluated in a separate testing set. RESULTS: Our cohort included 1008 female patients who underwent either unilateral or bilateral mastectomy (BM), with or without reconstruction, and with or without concomitant axillary lymph node staging at our institution. The median OR time was 4.67 hours (range; .70-16.35 hours). To create a predictive model, we divided our cohort into a training set of 504 patients and a testing set of 504 patients. Across the training set, body mass index (BMI), BM, nonconventional mastectomies, intraoperative frozen sections, receipt of neoadjuvant chemotherapy, and reconstruction were associated with longer OR times on linear regression. A model generated from these findings on the training set was run on the testing set (Pearson correlation = .743 for predicted vs. actual OR times, P < .001). CONCLUSION: A number of preoperative factors such as BMI, unilateral vs. BM, type of mastectomy and reconstruction, use of intraoperative frozen sections, and receipt of neoadjuvant chemotherapy can influence OR times. Accurate predictions can be made using a simple model incorporating these factors.