Inter-semispinal Plane (ISP) Block for Postoperative Analgesia Following Cervical Spine Surgery: A Prospective Randomized Controlled Trial

Study Objective: We evaluated the perioperative analgesic effects of the inter-semispinal plane (ISP) block in patients undergoing posterior cervical spine surgery.

Design: Prospective, randomized, controlled, double-blinded trial.

Setting: Operating room and surgical ward.

Patients: 60 patients aged 18-60 years of either gender, ASA I-II, undergoing elective posterior cervical spine surgery.

Interventions: Patients were randomly assigned into a control group (general anesthesia only), ISP group received bilateral ultrasound guided ISP block at the level of C5 using 20 ml bupivacaine 0.25% on each side.

Measurements: Visual analog scale (VAS), intraoperative fentanyl and 24 h postoperative pethidine consumptions and time to first rescue analgesic request were documented.

Main Results: The median (quartiles) of 24 h postoperative rescue pethidine consumption was significantly lower in the ISP group [0 (0-46.25) mg] compared to that of the control group [143 (116.75-169.00) mg]; P < 0.001). VAS was significantly lower in the ISP group at 30 min, 1 h, 2 h,4 h, 6 h, 8 h and 12 h postoperative compared to control group (P < 0.05). At 18 and 24 h, VAS was not significantly different between groups. The median (quartiles) of intraoperative fentanyl consumption in the ISP group [0 (0-40.75) μg] was significantly lower compared to that of the control group [63.5 (39.5-90.25) μg]; P < 0.001]. The time to first rescue analgesic administration was significantly longer in the ISP group compared to the control group (P < 0.001).

Conclusion: Bilateral ultrasound-guided ISP block can provide decreased 24 h postoperative analgesic consumption as well as lower pain scores in the first 12 postoperative hours in patients undergoing posterior cervical spine surgery.