NCT06750835 - Efficacy of the Serratus Posterior Superior Intercostal Plane Block for Postoperative Analgesia in Breast Cancer Surger.(SPSIP) Block is a Novel Regional Anesthesia Technique Targeting the Dorsal Rami and Intercostal Nerves (T2-T6), Providing Sensory Blockade to Both the Posterior and Lateral Aspect | Crick | Crick