Relative Perioperative Analgesic Efficacy of Superficial Versus Deep Approach of Serratus Anterior Plane Block for Anterior Chest Wall Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Objectives: Both superficial (s) and deep (d) serratus anterior plane (SAP) blocks are effective for anterior chest wall surgeries, but there is little clarity on which is more effective. Hence, we conducted a systematic review and meta-analysis of randomized control trials (RCT) to evaluate the comparative efficacy of the two approaches for SAP block after anterior chest wall surgery.

Materials and methods: A systematic literature search was performed using PubMed, Embase, Scopus, and Cochrane Central Registers of Controlled Trials for eligible RCTs from inception until August 2023. The primary outcome was opioid consumption during the first 24 hours of the postoperative period. The secondary outcomes included pain scores at various intervals, intraoperative opioid consumption, time to first analgesic request, block-related complications, opioid-related side effects, and patient satisfaction scores. Statistical analysis of the pooled data was performed using Review Manager Version 5.3.

Results: We identified seven RCTs published between 2020 and 2022, enrolling 371 patients (186 in the sSAP block and 187 in the dSAP block). Moderate certainty of evidence suggests that both the approaches (deep and superficial) of SAP block were comparable for 24-hour oral morphine equivalent consumption with a mean difference (MD) of 3.78 mg (95% CI -1.70 to 9.29; P=0.18; I2=87%). The results of other secondary outcomes were comparable, including resting pain scores with an MD of 0.08 (95% CI -0.27 to 0.43; P=0.67; I2=87%) for early pain and MD of 0.63 (95% CI -1.28 to 0.01; P=0.05; I2=95%) for late pain scores, time to first analgesic request with MD of -0.41 hour (95% CI -1.40 to 0.59; P=0.42; I2=90%), and incidence of PONV (OR, 1.45 (95% CI 0.72 to 2.90; P=0.30; I2=0%).

Discussion: Current evidence does not support the preference for one approach of SAP block over the other for postoperative pain. Based on the available data, we recommend further future trials to determine any differences between these interventions.