FROST-STERN Trial: A Trial of Intraoperative Cryoablation for Post Operative Pain Management After Full Sternotomy
brief summary
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.
detailed description
FROST-STERN Research Protocol
1. Study Rationale and Background Median sternotomy remains the gold standard surgical approach for complex open-heart surgeries, including coronary artery bypass grafting (CABG) and valve replacements. However, it is inherently associated with severe acute and chronic postoperative pain. Approximately 28% of patients experience chronic post-sternotomy pain, with 4% characterizing it as severe.
Inadequate acute pain management often results in patient "splinting" and impaired respiratory effort. This poor bronchopulmonary hygiene significantly increases the risks of acute postoperative lung complications, such as atelectasis and pneumonia, which can extend intensive care unit (ICU) and hospital length of stay (LOS). The pathophysiology of this pain stems from direct surgical trauma to peripheral nerve pathways, traction-induced brachial plexus injury, and intercostal neuralgia resulting from internal mammary artery harvesting.
While traditional pain protocols rely heavily on systemic opioids, high narcotic burdens carry substantial side effects, including respiratory depression, sedation, and ileus. Traditional regional plane blocks offer relief that lasts only hours rather than months. This trial introduces intraoperative intercostal nerve cryoablation (INC) into a standardized cardiac Enhanced Recovery After Surgery (ERAS) pathway. By utilizing extreme cold to induce temporary, reversible Wallerian degeneration, INC offers a localized, non-addictive, long-acting analgesic solution designed to reduce early postoperative opioid reliance and accelerate the recovery of objective pulmonary function. 2. Participant Recruitment, Screening, and Consent Potential subjects will be identified and recruited from the Cardiac Surgery Clinic (outpatients) or the Inpatient Cardiac Surgery Service days to weeks prior to their scheduled operation.
* Screening: The Principal Investigator (PI) or a designated Study Nurse will review patients' electronic medical charts against strict eligibility criteria. * Consent Process: Eligible patients will be approached in a private clinic room or at their hospital bedside. The study team will spend 5 to 10 minutes presenting the trial, emphasizing its voluntary nature. Patients will be provided with the written Informed Consent Form (ICF) to read over. Ample time will be provided to answer all questions. To verify comprehension prior to signing, the investigator will ask the patient several validating questions about the study. Once consent is obtained, it will be documented via a formal clinical note in the patient's medical record, and a copy of the ICF will be given to the participant. 3. Randomization, Allocation, and Blinding The FROST-STERN trial is a prospective, randomized, double-blind, parallel-group, sham-controlled trial with a target enrollment of 100 subjects.
official title
FROST-STERN: Functional Recovery and Opioid Sparing Technique for STERNotomy A Randomized Trial of Intraoperative Intercostal Cryoablation for Postoperative Pain Management Following Full Sternotomy