Long-term Efficacy of Pectoserratus Plane Block (PSPB) for Prevention of Post-mastectomy Pain Syndrome

Objectives: Pectoserratus plane block (PSPB) leads to lower postoperative pain intensity. We examined whether PSPB could also reduce the incidence of post-mastectomy pain syndrome (PMPS) in women undergoing breast cancer surgery. Methods: We performed an extension study of a randomized trial that compared PSPB versus control in women undergoing mastectomy. The primary outcome was any chronic pain at the surgical site or adjacent areas, defined as persistent/recurrent pain lasting ≥3 months. Secondary outcomes included neuropathic pain (score ≥4 in the Douleur Neuropathique 4 questionnaire), use of analgesic/anti-inflammatory drugs, pain intensity through the short-form McGill Pain Questionnaire, and type, frequency, and location of the pain. Results: Of the 60 patients that completed the 24-hour follow-up (short-term trial), 53 (88%) completed the long-term follow-up (27 in the PSPB group and 26 in the placebo group). Six of 27 patients (22%) in the PSPB group and 17 of 26 patients (65%) in the placebo group reported any chronic pain (relative risk [RR], 0.34; 95% confidence interval [95% CI]=0.16–0.73, P =0.005). The risk of neuropathic pain was also lower in the PSPB group than in the placebo group (18.5% vs. 54%, respectively; RR, 0.34; 95% CI=0.14–0.82, P =0.02). There were no differences regarding all other pain-related outcomes considering the patients who developed PMPS. Discussion: The results suggest that, in the long term, PSPB-treated participants were associated with a statistically significantly lower risk of PMPS than those who received standard general anesthesia. Trial Registration: ClinicalTrials.gov (NCT03966326).