Chest Wall Fascial Plane Blocks for Cardiac Surgery via Median Sternotomy: A Network Meta-Analysis

Y. Bu¹, S. Saeed¹, A. Sharkey¹, M. Robitaille¹, A. Manji¹, U. Ahmed¹, P. Ambarus¹, K. Khabbaz¹, F. Mahmood², R. Matyal^1
1Beth Israel Deaconess Medical Center, Boston, Massachusetts ²Beth Israel Deaconess Medical Center, Sharon, Massachusetts

Purpose: Several chest wall fascial plane blocks have been proposed and investigated separately in cardiothoracic surgeries, but their relative efficacy in cardiac surgeries via median sternotomy remains unknown. We aimed to quantitatively evaluate and rank the relative efficacy of different modalities for multiple clinical outcomes by network meta-analysis.

Methods: We followed the PRISMA-NMA reporting guidelines and registered our research on PROSPERO (registration number CRD42022345047). Randomized controlled trials (RCTs) that met the inclusion criteria [main criteria are: participants age > 18, undergoing elective cardiac surgery under general anesthesia via median sternotomy; interventions including chest wall fascial plane blocks with/without patient-controlled analgesia (PCA)] were retrieved from 4 databases. A random-effect network meta-analysis was conducted. Outcomes included 24-hour postoperative opioid consumption [converted to an equivalent dose of intravenous morphine (mg)], postoperative mechanical ventilation time (mins), and pain assessment score. Confidence in the evidence for the primary outcomes was evaluated using CINeMA (Confidence-In-Network-Meta-Analysis). Interventions were then ranked by a minimally contextualized framework of the GRADE approach.

Results: 24 RCTs were included in this network meta-analysis. A total of five plane blocks [erector spinae plane block (ESPB), pecto-intercostal fascial block (PIFB), transversus thoracic muscle plane block (TTMPB), multi-site parasternal infiltration (MSPI), pectoral nerve block type II (PEC II)] were reported. Interventions were grouped according to the GRADE framework (category I to III, based on P-value and evidence confidence level). 20 RCTs with 1159 patients contributed to the network of 24-hour postoperative opioid consumption (Fig. A), where ESPB (MD = -44.77, 95% CI -57.63 ~ -31.91) fell in category I, followed by MSPI. 20 RCTs with 1186 patients contributed to the network of mechanical ventilation time (Fig. B), where PEC II was the only statistically significant intervention. 12, 19, and 18 RCTs with 664, 1025, and 958 patients contributed to the pain score network, respectively. Anterior parasternal blocks (MSPI, TTMPB) and posterior paraspinal modality (ESPB) exhibit two patterns: anterior blocks showed a moderate yet lasting effect over 24 hours, while ESPB showed a peaked analgesic effect, which wore off in about 12 hours. The effectiveness of MSPI may be due to the high proportion of postoperative, multi-site injections and continuous blocks in the included RCTs.

Conclusion: Based on current evidence, our study suggests that chest wall fascial plane blocks (ESPB and MSPI) can reduce the consumption of postoperative opioids in patients undergoing cardiac surgery via median sternotomy. Fascial plane blocks can also provide analgesic effects in the first postoperative 24-hour period and reduce pain scores (ESPB, MSPI, and TTMPB). Chest wall block modalities show different duration characteristics and analgesia strength depending on the performance site. Future research direction could be whether a multi-site, continuous fascial plane block is more beneficial than the single-site, one-time injection technique.

Identify the source of the funding for this research project: Department internal funding