Comparison of Paravertebral Block and Deep Parasternal Intercostal Plane Block in Cardiac Surgery

Median sternotomy remains the most commonly used surgical approach in adult cardiac surgery and is associated with substantial postoperative pain. Inadequate pain control after sternotomy may lead to increased opioid consumption, delayed mobilization, prolonged extubation time, respiratory complications, and extended intensive care unit or hospital stay. Despite the routine use of multimodal analgesia, postoperative pain after sternotomy continues to be a significant clinical problem.

Ultrasound-guided regional analgesia techniques have increasingly been used as part of multimodal pain management strategies in cardiac surgery. Thoracic paravertebral block is one of the established regional techniques that can provide effective hemithoracic analgesia. However, its use may be limited by technical difficulty, dependence on operator experience, and the potential risk of complications. In contrast, deep parasternal intercostal plane block is a more superficial fascial plane block that targets the anterior cutaneous branches of the intercostal nerves, which play an important role in sternotomy-related pain. Although both techniques have shown potential benefit in previous studies, direct comparative data between thoracic paravertebral block and deep parasternal intercostal plane block are limited.

This study is designed as a prospective, randomized, controlled, single-center clinical trial in adult patients undergoing elective cardiac surgery via median sternotomy. A total of 80 patients aged 18 to 65 years with American Society of Anesthesiologists physical status II-III will be enrolled. Eligible participants who provide written informed consent will be randomly assigned in a 1:1 ratio to one of two groups: the thoracic paravertebral block group or the bilateral deep parasternal intercostal plane block group. Randomization will be performed using a computer-generated sequence, and group assignments will be concealed in sealed, opaque, sequentially numbered envelopes.

All patients will undergo surgery under standard general anesthesia and routine perioperative monitoring according to institutional practice. In addition to standard anesthesia and multimodal analgesia, patients in one group will receive ultrasound-guided thoracic paravertebral block, while patients in the other group will receive ultrasound-guided bilateral deep parasternal intercostal plane block before surgery. All block procedures will be performed by an experienced anesthesiologist. Surgical procedures will be carried out by the same cardiovascular surgical team using the standard median sternotomy technique in order to reduce procedural variability.

The primary outcome measure is total opioid consumption during the first 24 hours after surgery. Secondary outcome measures include postoperative pain scores assessed with the Visual Analog Scale at 0, 2, 4, 6, 12, and 24 hours, additional analgesic requirements, analgesia-related adverse effects such as nausea, vomiting, or respiratory depression, and extubation time. Demographic and clinical variables including age, sex, body mass index, ASA class, diabetes mellitus, comorbidities, internal mammary artery preparation, and duration of surgery will also be recorded.

The hypothesis of the study is that there will be a significant difference in postoperative analgesic effectiveness between thoracic paravertebral block and bilateral deep parasternal intercostal plane block in adult patients undergoing cardiac surgery through median sternotomy. The findings are expected to contribute to the evidence base regarding the comparative effectiveness and clinical applicability of these two active regional analgesia techniques in post-sternotomy pain management.