TAP Blocks Decrease Postoperative Prescriptions in Opioid-Na´ve Patients Undergoing Autologous Breast Reconstruction
Arhana Chattopadhyay MD1, Jennifer Shah2, Vy Ho MD1, Pooja Yesantharao MS3, Clifford Sheckter MD4, Rahim Nazerali MD1 1Stanford Hospital, Stanford, CA 2Stanford University, Stanford, CA 3The Johns Hopkins Hospital, Baltimore, MD 4University of Washington Hospital, Seattle, WA
Background: The transversus abdominus plane (TAP) block is used to reduce postoperative donor site pain in patients undergoing autologous breast reconstruction with an abdominally-based free flap. Current evidence from single institutions has yielded mixed results in TAP block effectiveness. This study aims to determine the effect of TAP blocks on postoperative opioid prescriptions and the rates of conversion to chronic opioid use leveraging national data.
Methods: The ClinformaticsTM Data Mart (OptumInsight, Eden Prairie, MN) is a de-identified national claims database from a private insurer. From 2003-2019, adult female patients within a 1-year continuous enrollment period were queried. Common procedural terminology codes for autologous breast reconstruction with an abdominally-based free flap and for placement of an intraoperative TAP block were used. Patients who underwent additional procedures within 180 days after their index operation were excluded. Patients were considered opioid-na´ve if they did not fill a narcotic prescription from 1 year to 30 days prior to surgery. Morphine milligram equivalents (MME) were calculated for postoperative prescriptions which were filled within 30 days after surgery. Chronic opioid use (COU) was defined as receiving 4 unique prescriptions or a 60-day supply between 30 and 180 days after surgery. Schapiro-Wilk testing was used to determine whether continuous variables were normally distributed. Chi squared and Mann-Whitney-Wilcoxon tests were used for statistical analysis. The two-tailed threshold for statistical significance was 0.05. All analyses were completed using Stata 16.
Results: Of 4122 patients meeting criteria (mean age 51.2 ▒ 9.0 years), 183 (4.4%) had a TAP block placed. Within 30 days of surgery, postoperative MME/day was significantly lower in patients who received a TAP block (14.77 vs. 17.94 MME/day, p = 0.005). Postoperative COU did not significantly differ between those patients who underwent TAP blocks versus those who did not (7.65% vs 7.15%, p = 0.80). Similarly, mean length of stay did not differ between the two groups (3.45 vs. 3.38 days, p = 0.67).
Conclusion: Following autologous breast reconstruction, TAP blocks were associated with fewer opioid prescriptions in the immediate postoperative period. However, these effects were not lasting given that the percentage of patients who developed COU was similar to the non-TAP cohort. Additional investigations are needed to understand how the benefits of TAP blocks can be extended into the later postsurgical period.
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