PURPOSE: Transversus abdominis plane (TAP) blocks have been shown to significantly reduce pain and narcotic consumption following several major abdominal surgeries; however, their widespread adoption in microsurgical breast reconstruction has been slow. This study investigates the current body of evidence on the use of TAP blocks in microsurgical breast reconstruction.
METHODS: A systematic review of patients undergoing autologous breast reconstruction with TAP blocks was performed. Information on patient demographics, pain scores, and postoperative narcotic consumption were noted. Meta-analysis of hospital length of stay (LoS) was performed using a random effects model.
RESULTS: Ten studies published between 2011 and 2018 were included. All studies were either a randomized control trial/prospective case-control study (LoE II [5, 50%]) or a retrospective cohort study (LoE III [5, 50%]). Across all studies, 174 patients (5 studies) received a single intraoperative TAP block injection, 185 patients (4 studies) received a TAP catheter for intermittent postoperative analgesia, and 325 patients served as controls for a total of 684 included patients. The majority of TAP block delivery techniques were ultrasound guided (7/10 studies). Liposomal bupivacaine (LB) was the most commonly used analgesic (4 studies, 139 patients) followed by conventional bupivacaine (3 studies, 105 patients). Studies reported on a mixed cohort of both unilateral and bilateral, and immediate and delayed reconstructions. Abdominally based flaps investigated included deep inferior epigastric perforator, MS-TRAM, TRAM, and superficial inferior epigastric artery flaps. Nine of the included studies analyzed postoperative narcotic consumption with the use of TAP blocks. Of those, all but one found a significant reduction in oral, intravenous, and/or total morphine requirements in the experimental TAP group when either the daily average and/or total inpatient consumption was compared to the control. Only 1 study performed a formal analysis of cost with the use of a LB TAP block and found no statistically significant increase in hospital expenses in the TAP block group. Hospital LoS was significantly shorter for patients undergoing single intraoperative TAP block injection with any analgesic as compared to standard narcotic-based protocols (mean difference, −0.95 days; 95% confidence interval, −1.72 to −0.17 days; P = 0.02). Looking at TAP blocks specifically with LB, there was a mean decrease of 0.83 days as compared to the control which was not statistically significant (95% confidence interval, −1.90 to 0.25 days; P = 0.13). No study reported adverse outcomes related to the TAP injections themselves. One prospective cohort study specifically looked at chronic postsurgical pain outcomes following the use of standard 0.25% bupivacaine delivered via TAP catheters and found no significant reduction in the incidence of chronic postsurgical pain at 6 and 12 months.
CONCLUSIONS: Several high-quality studies have demonstrated that TAP blocks in microsurgical breast reconstruction significantly reduce narcotic consumption and hospital LoS. However, there remains considerable variability with regard to delivery technique, analgesic type, and dose. Although the current data support the use of TAP blocks in autologous breast reconstruction, additional studies with more standardized protocols should be performed to determine the most optimal practice.