Ultrasound-guided thoracic paravertebral nerve block in superficial versus deep superior costotransverse ligament: a comparative study of 106 cases

To compare the analgesic effect and postoperative recovery quality of ultrasound-guided superficial and deep injection to superior costal transverse ligament (SCTL) for local anesthetics in thoracic paravertebral block (TPVB) combined with patient-controlled intravenous analgesia (PCIA) for postoperative analgesia in patients undergoing thoracoscopic surgery.

A total of 106 patients undergoing elective thoracoscopic surgery in the thoracic surgery department of our hospital from May 2021 to September 2021 were eligible for inclusion. They were randomly divided into SCTL superficial block group (Group S) and SCTL deep block group (Group T). Routine anesthesia induction and maintenance were performed in the both groups. After extubation, TPVB was operated under the guidance of ultrasound, and corresponding analgesic agent was injected into the superficial or deep surface of SCTL for local anesthetics, with 20 mL of 0.375% ropivacaine hydrochloride for single-point TPVB on the affected side, and PCIA was given at the same time. The positioning time and puncture time of ultrasonic image were recorded, the distance from the tip of ultrasonic image needle to pleura was measured, and the pleural depression and puncture related complications of ultrasonic image were observed. Visual analogue score (VAS) in resting and exercise (cough) states was evaluated at 5, 10, 20 and 30 min, and 4, 12 and 24 h (T_0~6) after block. The use of analgesic pump within 24 h after operation was observed in terms of sufentanil dosage, first compression time, effective compression times, and actual compression times. QOR-40 was employed to investigate the quality of recovery before and 24 h after operation.

Group S had significantly shorter puncture time (P<0.05) and longer distance from the tip of the needle to the pleura on ultrasound image when compared with Group T (P<0.05). Pleural depression could be observed in ultrasound image of 15 cases in Group S and of 51 cases in Group T (P<0.05). There was 1 case of epidural block in Group T. The VAS score at T₆ in exercise (cough) state was obviously higher in Group S than Group T (P<0.05). But, because the scores in both groups belonged to the range of mild pain score, no clinical difference was identified between the 2 groups. There were no statistical differences in the other VAS scores in resting and exercise (cough) states, time of image positioning under ultrasound guidance, and use of analgesic pump within 24 h after operation, and QOR-40 scores before and 24 h after operation between the 2 groups.

Both ultrasound-guided superficial and deep injection of analgesic drugs into SCTL for TPVB can provide effective postoperative analgesia and equivalent postoperative recovery quality for patients after thoracoscopic surgery. SCTL can be used as injection reference for ultrasound guidance. But the superficial injection of SCTL is safer, easier and simpler in operation.