Transversus Abdominis Plane Block With Liposomal Bupivacaine vs. Regular Anesthetics for Pain Control After Surgery: A Systematic Review and Meta-Analysis

Comparison of Liposomal Bupivacaine to a Local Analgesic Cocktail for Transversus Abdominis Plane-Blocks in Abdominally-Based Microvascular Breast Reconstruction

BACKGROUND

Transversus Abdominis Plane (TAP) blocks can improve pain control and decrease opioid usage within an ERAS protocol, in patients undergoing abdominally-based autologous breast reconstruction. The author has transitioned to using a local analgesic cocktail in place of liposomal bupivacaine for TAP blocks. The purpose of this study is to compare post-operative opioid use in patients who received the different TAP blocks.

METHODS

A retrospective review of patients undergoing abdominally-based autologous breast reconstruction between November 2015 and December 2019 was performed. The study group received Bupivacaine, Ketorolac, Dexmedetomidine, and Dexamethasone, and the control group received Liposomal Bupivacaine +/- Bupivacaine, Ketorolac, or Dexmedetomidine, as a TAP block. The primary outcome of interest was post-operative opioid use and pain scores.

RESULTS

A total of 104 women met inclusion criteria: 36 in Group A (pre-ERAS, pre-TAP), 38 in Group B (ERAS, TAP with liposomal bupivacaine), and 30 in Group C (ERAS, TAP with local anesthetic cocktail). Total and average daily OME consumption were significantly less for Group C in the inpatient phase (Group A: 633, B: 240, C: 135; p<0.0001) (Group A: 137, B: 56, C: 29; p<0.0001). Patients in Group C were prescribed significantly less outpatient OMEs (Group A: 79, B: 74, C: 52; p=0.01).

CONCLUSION

TAP blocks are a significant component of an ERAS protocol for abdominally-based breast reconstruction. Liposomal bupivacaine is a popular option for TAP blocks. Our results demonstrate that a local anesthetic cocktail, composed of economical and readily available medications, can provide excellent patient pain control and decrease post-operative opioid use.

Sodium Channels and Local Anesthetics-Old Friends With New Perspectives

The long history of local anesthetics (LAs) starts out in the late 19th century when the content of coca plant leaves was discovered to alleviate pain. Soon after, cocaine was established and headed off to an infamous career as a substance causing addiction. Today, LAs and related substances-in modified form-are indispensable in our clinical everyday life for pain relief during and after minor and major surgery, and dental practices. In this review, we elucidate on the interaction of modern LAs with their main target, the voltage-gated sodium channel (Navs), in the light of the recently published channel structures. Knowledge of the 3D interaction sites of the drug with the protein will allow to mechanistically substantiate the comprehensive data available on LA gating modification. In the 1970s it was suggested that LAs can enter the channel pore from the lipid phase, which was quite prospective at that time. Today we know from cryo-electron microscopy structures and mutagenesis experiments, that indeed Navs have side fenestrations facing the membrane, which are likely the entrance for LAs to induce tonic block. In this review, we will focus on the effects of LA binding on fast inactivation and use-dependent inhibition in the light of the proposed new allosteric mechanism of fast inactivation. We will elaborate on subtype and species specificity and provide insights into modelling approaches that will help identify the exact molecular binding orientation, access pathways and pharmacokinetics. With this comprehensive overview, we will provide new perspectives in the use of the drug, both clinically and as a tool for basic ion channel research.