Transversus Abdominis Plane Blocks in Microsurgical Breast Reconstruction: An Analysis of Pain, Narcotic Consumption, Length of Stay and Cost Implications

Purpose: Transversus abdominis plane (TAP) blocks are increasingly utilized in abdominally-based microvascular breast reconstruction. Studies, however, have not reliably shown improvements in postoperative pain,^1-3 and cost implications remain unknown. The purpose of this study is to elucidate the global effects of TAP blocks on reconstructive and institutional outcomes after microvascular breast reconstruction.

Methods: Patients undergoing abdominally-based microvascular breast reconstruction from 2015-2017 were reviewed. Length of stay, complications, narcotic consumption, donor-site pain and hospital expenses were compared between patients that did and those that did not receive TAP blocks with liposomal bupivacaine. Patient that did not receive TAP blocks had local infiltration of the rectus fascia and abdominal flaps with bupivacaine.

Medication consumption was summated for the first 72 hours of inpatient stay and donor-site pain was determined from nursing-reported pain scores. Hospital expenses were calculated from estimates of average hospital expenses per inpatient day, medication costs including liposomal bupivacaine, and operating room expenses. A sub-population analysis was performed for high-body mass index (BMI) patients (BMI≥25).

Results: Fifty patients (43.9%) received TAP blocks and 64 patients (56.1%) did not. 98.8% of patients with TAP blocks underwent deep inferior epigastric artery perforator (DIEP) flap reconstruction and 1.2% had muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flaps compared to the no-TAP group which had 94.2% DIEP, 3.9% ms-TRAM and 1.9% superficial inferior epigastric artery (SIEA) flaps (p=0.2414). Of the 50 TAP blocks, 27 (54.0%) were performed under ultrasound guidance. Patients in the no-TAP block group had a higher rate of major mastectomy flap necrosis (17.5% versus 7.4%, p=0.0493). The remainder of reconstructive and donor-site complications were comparable. There were no complications secondary to TAP blocks themselves.

Patients with TAP blocks had significantly decreased oral (46.5 versus 79.9 mg oxycodone equivalents, p=0.0001) and total (25.9 vs 44.4 mg morphine equivalents, p<0.0001) narcotic consumption as well as less donor-site pain (3.3 versus 4.3, p<0.0001). There was no significant difference in hospital expenses between the two cohorts ($21,531.53 versus $22,050.15 per patient, p=0.5659). High-BMI patients with TAP blocks additionally had a significantly shorter length of stay (3.8 versus 4.4 days, p=0.0094) compared to those without blocks.

Multivariable linear regression analysis revealed TAP blocks as the only independent predictor of decreased total narcotic usage (p<0.0001) and average abdominal pain (p<0.0001) post-operatively.

Conclusions: TAP blocks with liposomal bupivacaine reduce postoperative narcotic consumption as well as donor-site pain in all patients after abdominally-based microvascular breast reconstruction without increasing hospital expenses. TAP blocks additionally decrease length of stay in patients with BMI≥25.

References

1. Hivelin M, Wyniecki A, Plaud B, Marty J, Lantieri L. Ultrasound-guided bilateral transversus abdominis plane block for postoperative analgesia after breast reconstruction by DIEP flap. Plast Reconstr Surg. 2011;128:44-55.
2. Afonso A, Oskar S, Tan KS, et al. Is Enhanced Recovery the New Standard of Care in Microsurgical Breast Reconstruction? Plast Reconstr Surg. 2017;139:1053-1061.
3. Hunter C, Shakir A, Momeni A, et al. Transversus Abdominis Plane Block and Free Flap Abdominal Tissue Breast Reconstruction: Is There a True Reduction in Postoperative Narcotic Use? Ann Plast Surg. 2017;78:254-259.