Parasternal Intercostal Nerve Block and Chronic Pain After Cardiac Surgery

Overview

Chronic post-sternotomy pain is a common but under-recognised complication of cardiac surgery, reported in roughly 11 to 56 percent of patients and capable of persisting for years after the operation. Effective control of pain in the early postoperative period is thought to reduce the central sensitisation that drives the transition from acute to chronic pain. This single-centre, prospective, randomised, patient- and assessor-blinded controlled trial investigates whether an ultrasound-guided bilateral parasternal intercostal nerve block, performed preemptively after induction of general anaesthesia and before surgical incision, reduces the incidence of chronic pain three months after cardiac surgery performed through a median sternotomy. A total of 174 adults scheduled for elective cardiac surgery will be randomised in a 1:1 ratio to receive either the block plus the institution's standard multimodal analgesia protocol, or the standard protocol alone. The primary endpoint is the incidence of chronic post-sternotomy pain at three months, assessed with the Turkish version of the Brief Pain Inventory - Short Form. Secondary endpoints cover acute pain scores, opioid consumption, postoperative nausea and vomiting, and complications.

Design and setting. The trial will be conducted in the Department of Anesthesiology and Reanimation, University of Health Sciences Istanbul Bakirkoy Dr. Sadi Konuk Training and Research Hospital. Eligible patients will be identified at the preoperative anaesthesia assessment and written informed consent will be obtained. Randomisation and blinding. Participants will be allocated 1:1 using sequentially numbered, opaque, sealed envelopes prepared in advance. Patients and the investigator performing postoperative assessments will be unaware of group assignment; the anaesthesiologist performing the block cannot be blinded. Intervention. In the block group, after induction of general anaesthesia and before surgical incision, a bilateral parasternal intercostal nerve block will be performed in the supine position with a high-frequency linear ultrasound probe (6-15 MHz) and a 22 G, 80 mm echogenic block needle. Anaesthetic and analgesic management, identical in both groups. Assessments. Pain is scored with the Numeric Rating Scale at rest and on movement at 1, 6, 12 and 24 hours after extubation. Opioid consumption, postoperative nausea and vomiting and any complications are recorded. At three months patients are contacted by telephone and assessed with the Brief Pain Inventory - Short Form, validated in Turkish by Ataman and colleagues. Sample size. The calculation is based on the primary endpoint. 87 participants per group will be enrolled, for a total of 174.