Intercostal Nerve Cryoablation for Postoperative Pain

(FROST-STERN Trial)

Background and Rationale: Open-heart surgery via a median sternotomy is associated with severe acute postoperative pain. This pain can impair a patient's ability to take deep breaths and cough effectively which increases the risk of postoperative lung complications such as atelectasis (collapsed lung) or pneumonia. Traditional pain management protocols rely heavily on opioid medications, which carry systemic side effects including respiratory depression, sedation, and nausea. While short-acting regional nerve blocks are helpful, their effects often wear off within the first 24 hours. The result is a suboptimal duration of pain relief for the remaining critical early recovery window. Intra-operative intercostal nerve cryoablation (temporary nerve freezing) offers a prolonged, localized, and non-opioid alternative. By temporarily interrupting pain signals along the chest wall, this technique may preserve early respiratory function and reduce systemic narcotic requirements during acute recovery.

Study Objective:The objective of this study is to evaluate whether adding bilateral intra-operative intercostal nerve cryoablation (levels T2 through T6) improves the recovery of pulmonary function and reduces acute pain in patients undergoing elective cardiac surgery via a full median sternotomy.

Study Design:This is a prospective, randomized, double-blind, sham-controlled, single-center trial. A total of 100 adult patients scheduled for elective first-time cardiac surgery (such as coronary artery bypass grafting or valve replacement) will be randomized in a 1:1 ratio into either an intervention or control group.

Intervention Group: Patients will receive bilateral intraoperative intercostal nerve cryoablation at levels T2-T6 from within the surgical field prior to sternal closure.

Control Group: Patients will receive standard-of-care multimodal analgesia. Patients, clinical staff managing postoperative care, and data assessors will be fully blinded to the treatment assignment.

Primary Outcome:Pulmonary Function Recovery (FEV1 and Incentive Spirometry): Measured as the percentage of the patient's preoperative baseline Forced Expiratory Volume in 1 second (FEV1) and incentive spirometry recovered at 48 hours postoperatively.

Key Secondary Outcomes:

Cumulative postoperative opioid consumption (measured in Morphine Milligram Equivalents, or MME) during the first 72 hours.

Subjective pain intensity scores at rest and during deep inspiration/coughing (using a 0-10 Numerical Rating Scale) at 12, 24, 48, and 72 hours.

Key recovery milestones, including time to first extubation, intensive care unit (ICU) length of stay, and total hospital length of stay.

Incidence of long-term or chronic post-sternotomy pain syndrome at 3 and 6 months follow-up.