Quadrant and dermatomal analysis of sensorial block in ultrasound-guided erector spinae plane block

Abstract

Objective: as a novel procedure now gaining popularity, erector spinae plane block has been the subject of many studies. However, dermatomal coverage of the sensory block caused by erector spinae plane block has been rarely studied. The goal of this study is to evaluate the sensory block resulting from erector spinae plane block applied at the T9 vertebral level. Materials and methods: this observational, prospective, blinded study was conducted on 50 adult patients undergoing laparoscopic abdominal surgery. All patients underwent bilateral erector spinae plane block at the T9 level after completion of the surgery while under general anesthesia. In order to further evaluate the sensory blockade, we divided the hemiabdomen-hemithorax region into 4 quadrants: dorsal-medial, dorsallaterel, ventral-lateral, and ventral-medial. The sensorial evaluation was performed using the pinprick test, 2 hours following the application of erector spinae plane block. Results: a total of 28 female and 22 male patients were examined in this study. Complete failure of the block was recorded in 7 patients, with no thoracic/lumbar segmental or quadrant involvement. Successful sensory block was achieved in 67% of the dorsolateral quadrants, 58% of the dorsomedial quadrants, 69% of the ventrolateral quadrants, and 55% of the ventromedial quadrants. Conclusion: cutaneous sensory block of erector spinae plane block at T9 vertebral level revealed variable results and low failure rates. Administration of erector spinae plane block for postoperative analgesia in thoracoabdominal surgeries requires further randomized controlled trials to confirm its effectiveness and convenience.