The incidence of post amputation syndrome after pericapsular nerve group block versus sciatico-femoral nerve block in patients undergoing above knee amputation

Abstract

Background & objective: Regional anesthesia for orthopedic procedures has been widely practiced around the globe, and it has been employed either alone or in combination with general anesthesia. An above knee amputation will need blockade of both femoral and sciatic nerves for successful pain control and help with peripheral sensitization for the patient. Pericapsular nerve group (PENG) block is a novel regional nerve block to provide analgesia in fractured hip patients. We assessed the effectiveness of this block compared to sciatico-femoral block and the incidence of post amputation syndrome in patients undergoing above knee amputation. Methodology: This randomized controlled single-blinded study was carried out on 30 patients with lower limb bone tumors indicated for above knee amputation admitted to surgery clinic, National Cancer Institute, Cairo University. The duration of study was from January 2021 to May 2022. Patients were randomized equally using opaque sealed envelopes into 2 groups Group A: (n = 15) pericapsular nerve group block group (PNGB) to receive 20 mL of 0.125% bupivacaine with 4 mg dexamethasone at the pubic ramus just medial to the anterior inferior iliac spine (AIIS). Group B: (n = 15) patients received sciatico-femoral block with a mixture of 20 mL 0.125% bupivacaine with 4 mg dexamethasone injected in the femoral and sciatic nerve. Postoperative VAS scores, the time to first analgesic request was and the total morphine consumed as rescue analgesic were recorded. Results: Time to first analgesic request was significantly prolonged in group B than group A (P < 0.001). Total morphine dose in first 24 h postoperative and in first 48 h postoperative were significantly lower in group B than in group A (P < 0.001 and 0.003 respectively). VAS scores were significantly lower at 2, 4 and 8 h in group B than group A (P < 0.05) and were insignificantly different at 12, 24 h, and on 2nd and 7th day between the two groups. Phantom limb syndrome frequency was significantly lower at 1, 2, 3 and 6 months in group B than in group A (P < 0.05); at 6 mo it was noted in 10 (66.67%) patients in group A and 4 (26.67%) in group B with 2.5 (1:6.23) RR (95% CI) (P = 0.028). Conclusions: Sciatico-femoral block has better outcomes than pericapsular nerve block in patients undergoing above knee amputation regarding analgesic effect and the development of phantom limb syndrome.