PECTO-INTERCOSTAL FASCIAL PLANE BLOCK FOR PREVENTING CHRONIC POST-SURGICAL PAIN: THE ROLE OF SYMPATHETIC-MEDIATED CENTRAL SENSITIZATION

Abstract

Background: Chronic post-surgical pain (CPSP) is a debilitating complication affecting 10-50% of patients following thoracic and cardiac surgery, with sympathetic nervous system (SNS) dysregulation increasingly recognized as a central driver of the neuroplastic changes that perpetuate it. The pecto-intercostal fascial plane block (PIFB) is an ultrasound-guided regional anesthesia technique targeting the fascial plane between the pectoralis major and the internal intercostal muscles. While its acute analgesic efficacy has been demonstrated, its capacity to attenuate sympathetically mediated central sensitization and thereby prevent CPSP remains unexplored. In this prospective, randomized, double-blind, placebo-controlled trial, we aimed to investigate whether preoperative PIFB reduces the incidence of CPSP through sympathetic modulation, assessed by galvanic skin response (GSR), skin temperature, and validated pain outcome measures.

Methods: Eighty adult patients aged 18-70 years, scheduled for elective cardiac surgery via median sternotomy under general anesthesia, were enrolled. Patients were randomly allocated in a 1:1 ratio to the PIFB group (bilateral injection of 40 mL of 0.375% ropivacaine into the pecto-intercostal fascial plane) or the control group (bilateral injection of 40 mL of 0.9% normal saline). The co-primary outcomes were the incidence of CPSP at 3 months post-surgery, assessed by the Numeric Rating Scale (NRS), and the extent of sympathetic blockade, evaluated by GSR and the hot-cold test. Secondary outcomes included acute postoperative pain scores, opioid consumption, skin temperature change, hemodynamic parameters, neuropathic pain characteristics (SF-MPQ-2), quality of life (BPI), and anxiety and depression scores (HADS) at 3, 6, and 12 months.

Results: The incidence of CPSP at 3 months was significantly lower in the PIFB group compared to the control group (18.4% vs. 37.2%; p = 0.031). GSR measurements demonstrated a significant reduction in ipsilateral skin conductance in the PIFB group compared to baseline (p < 0.001), indicating meaningful sympathetic activity, whereas between-group differences in the hot-cold test did not reach statistical significance (Group × Time interaction: p = 0.061). Ipsilateral skin temperature increased significantly in both groups after 30 minutes, but the rate of increase was greater in the PIFB group (p = 0.019). Acute postoperative NRS scores at rest and during coughing were significantly lower in the PIFB group at 24, 48, and 72 hours (all p < 0.05). Total opioid consumption within 5 days was significantly reduced in the PIFB group (sufentanil equivalent: 142.3 ± 38.1 μg vs. 198.6 ± 51.4 μg; p = 0.001). At 3 months, neuropathic pain features (SF-MPQ-2) and HADS scores were significantly improved in the PIFB group (p < 0.05). No serious block-related adverse events were observed.

Conclusion: Preoperative PIFB significantly reduces the incidence of CPSP following cardiac surgery via median sternotomy. The observed sympatholytic activity, as evidenced by GSR and skin temperature changes, suggests that attenuation of sympathetically mediated central sensitization may constitute an important mechanism underlying this benefit. PIFB represents a promising, safe, and technically accessible strategy for CPSP prevention in this high-risk surgical population.