Comparison of Unilateral Spinal Anesthesia and Popliteal Nerve Block for Postoperative Rebound Pain in Foot Surgeries - An Observational Study.

Background: Regional anesthesia techniques, such as unilateral spinal anesthesia and peripheral nerve blocks, are essential components of multimodal analgesia. Nonetheless, "rebound pain," an abrupt increase in nociceptive intensity following the cessation of the block, is inadequately defined and may compromise patient satisfaction and functional recovery.

Aims And Objectives: This study aimed to compare postoperative pain profiles, the incidence of rebound pain, and patient satisfaction following popliteal sciatic nerve block versus unilateral spinal anesthesia in elective foot surgeries.

Materials And Methods: This comparative observational study involved 70 adults (ages 25-65; the American Society of Anesthesiologists [ASA] I-III) scheduled for elective foot surgeries, who were assigned to either a popliteal nerve block group (Group P, n = 35) or a unilateral spinal anaesthesia group (Group S, n = 35). The onset of sensory blockade, numeric rating scale (NRS) pain ratings for 24 h, occurrence of rebound pain and patient satisfaction were documented. Data were analyzed utilizing the Mann-Whitney U and Chi-square tests, with P < 0.05 being significant.

Results: The baseline demographics, encompassing age, gender, and ASA status, were analogous across the groups. Group P demonstrated a markedly extended pain-free interval (7.57 ± 1.12 h vs. 2.46 ± 0.92 h; P < 0.001) but a delayed sensory block onset (14.69 ± 3.19 min vs. 8.91 ± 2.97 min; P < 0.001). Early postoperative NRS scores at 2 h and 4 h were significantly lower in Group P (P < 0.05), and secondary nadirs at 16 h and 20 h. The incidence of rebound pain did not differ significantly (17.1% vs. 11.4%; P = 0.495) between the two groups. Patient satisfaction increased dramatically with the popliteal block group (82.9% vs. 25.7%; P < 0.001).

Conclusion: The popliteal sciatic nerve block provides extended postoperative analgesia and enhanced patient satisfaction without increasing rebound pain, whereas unilateral spinal anesthesia facilitates quicker surgical preparation. In elective foot surgery requiring prolonged pain management, a popliteal block combined with multimodal analgesia is appropriate, although spinal anesthesia is preferable for a rapid start.