Intertransverse Process Block versus Erector Spinae Plane Block as Adjuncts to an Interpectoral Block for Breast...

This trial compared the efficacy of intertransverse process block (ITPB) with erector spinae plane block (ESPB), each in combination with an interpectoral block (IPB), with systemic analgesia for breast cancer surgery.

Ninety patients were randomized to ITPB/IPB, ESPB/IPB, or control under general anesthesia. The primary outcome was 24-hour morphine consumption. Secondary outcomes included intraoperative fentanyl use, numeric rating scale (NRS) pain scores, and recovery parameters. A 40% reduction in morphine consumption and a 2-point NRS decrease were prespecified as minimal clinically important differences (MCIDs). The IPB was applied equally in both intervention groups to reduce pectoral nerve-mediated pain.

Median (IQR) 24-hour morphine use was 0 mg (0-6), 3 mg (0-4), and 6 mg (3-6) in the ITPB/IPB, ESPB/IPB, and control groups, respectively. Morphine consumption did not differ between the ITPB/IPB and ESPB/IPB (median difference 0 mg; 95% CI 0 to 1; p = 0.275) but was lower in both groups compared with the control group (-2.5 mg; 95% CI -4 to 0; p = 0.014 and -2.7 mg; 95% CI -3 to 0; p = 0.003), exceeding the MCID despite modest absolute differences. Mean NRS pain scores were lower in both block groups than in the control group by approximately 1-1.2 points across the postoperative period. Intraoperative fentanyl use and time to ambulation were significantly reduced in both groups compared with the control. ITPB required longer performance time (+3.4 minutes; 95% CI 1.9 to 5.0; p < 0.001).

Both ITPB/IPB and ESPB/IPB provided comparable and effective analgesia after breast cancer surgery. Given its shorter performance time, ESPB may be the more practical option. However, because the IPB constituted a shared analgesic component in both groups, the independent analgesic effects of ITPB and ESPB remain uncertain and warrant further investigation.