Transversus abdominus plane blocks do not reduce rates of postoperative prolonged opioid use following abdominally based autologous breast reconstruction: a nationwide longitudinal analysis

Background The transversus abdominus plane (TAP) block reduces postoperative donor site pain in patients undergoing autologous breast reconstruction with an abdominally based flap. This study aimed to determine the effect of TAP blocks on rates of conversion to chronic opioid use. Methods The Clinformatics Data Mart was queried from 2003 to 2019, extracting adult encounters for abdominally based free and pedicled flaps based on common procedural terminology (CPT) codes. Patients were excluded if they had filled a narcotic prescription 1 year to 30 days prior to surgery. The exposure variable-TAP block-was identified by CPT codes. Outcomes were evaluated using morphine milligram equivalents (MME) from prescriptions filled between 30 days prior to and 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. Results Of the 4091 patients, (mean age 51.2 +/- 9.0 years), 181 (4.4%) had a TAP block placed. Perioperative MMEs/day, postoperative COU, and length of stay did not differ in patients who received a TAP block (p = 0.142; p = 0.271). Significant predictors of risk of conversion to COU included younger age, pedicled abdominal flap, Elixhauser comorbidity index score > 3, filling a psychiatric medication prescription, and filling a benzodiazepine prescription. Conclusions In patients undergoing autologous breast reconstruction with abdominally based flap reconstruction, TAP blocks do not decrease perioperative MME/day, conversion to chronic opioid use, or length of stay. These data suggest that intraoperative TAP block placement may be a low-yield opioid-reduction strategy. Level of evidence: Level III, risk/prognostic study