Wide dermatomal coverage after combined block targeting the space between the endothoracic fascia, diaphragm, and costodiaphragmatic recess and the posterior transversus abdominis plane in gynecologic laparoscopy: a case series.

The space between the endothoracic fascia, diaphragm, and costodiaphragmatic recess (SEDIC) is a newly identified anatomical space adjacent to the injection plane for the modified thoracoabdominal nerves block through the perichondrial approach (M-TAPA). Here we describe five cases involving patients who underwent gynecologic laparoscopy and received bilateral ultrasound-guided SEDIC blocks at the ninth intercostal space combined with bilateral posterior transversus abdominis plane blocks. Postoperative sensory distribution was assessed 30 min after surgery using a cold test. No block-related complications, symptoms of local anesthetic systemic toxicity, or respiratory compromise suggestive of phrenic nerve palsy were observed. All patients had extensive cold sensory deficits over the entire abdominal wall, with maximal cephalad extension to T1-T3 and partial extension beyond the posterior axillary line. The widest distribution was from T1 to L1. These findings suggest that the combined technique was associated with extensive thoracoabdominal sensory blockade. The unexpectedly wide cephalad sensory distribution may have been influenced by laparoscopic perioperative conditions such as pneumoperitoneum and Trendelenburg positioning, although injectate spread was not directly visualized. These observations suggest that post-block perioperative conditions may influence the resulting sensory coverage after SEDIC block under laparoscopic conditions.