Combined Psoas Compartment Block and Sciatic Nerve Block for Elective Lower Limb Surgeries

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Combined Psoas Compartment Block and Sciatic Nerve Block for Elective Lower Limb Surgeries

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Photo by Clay Banks on Unsplash

Photo by Clay Banks on Unsplash

Why is it important?

Introduction: Lower limb orthopedic interventions such as total hip arthroplasty (THA) and total knee arthroplasty (TKA) present a challenge to the anesthetist, as these procedures typically involve elderly patients often suffering from multiple co-morbid conditions. In addition, these procedures generate significant postoperative pain. The psoas compartment block (PCB) is an alternative approach which may circumvent many of the side-effects associated with central neuraxial blockade. Combined with a sciatic nerve block, unilateral anesthesia of the lower limb may be induced (‘Psoas compartment sciatic nerve block or PCSNB’). Aim and Objective of the Study: This study aimed at evaluation of the analgesic effect of combined psoas compartment block and sciatic nerve block in elective lower limb surgeries intra and post operatively. Primary Objective: To assess the effectiveness of the lower limb block based on 1) Sensory block 2) Motor block. Secondary Objective: time to request rescue analgesic. Material and Method: Design of the Study: Randomized controlled trial. Selection of Subjects: • Study involves adult patients of age 18 to 60 years of ASAps I - II posted for elective lower limb surgeries. • Sample size 60 •Randomization – computer generated random numbers • Monitors – NIBP, ECG and SpO2 • Anaesthesia: Combined psoas compartment block and sciatic nerve block. Sixty patients were subjected to psoas compartment block and sciatic nerve block using nerve stimulator 30 ml of 0.25% of bupivacaine for psoas compartment block + and 20 ml 0.25% of bupivacaine for sciatic nerve block. Under strict aseptic precautions, psoas compartment block performed by posterior approach and and sciatic nerve block by labat’s approach using peripheral nerve stimulator after obtaining twitch of quadriceps and calf muscle contraction and dorsiflexion of foot. • Assessment: Time of onset of analgesia and motor blockade, sensory blockade, total duration of analgesia and the time taken for 1st dose of rescue analgesia noted. Results: Sensory blockade by visual analogue scale reveals no pain upto 8 hours and almost complete block upto upto 6 hours in 73.3% of patients and good analgesic effect upto 9 to 10 hours in 48.3% (29 out of 60 patients) and at 10 to 11 hours is 51.7% (31 out of 60 patients) Motor blockade assessed by modified bromage scale at 2 hours revealed a score of 1 (complete block – unable to move feet or knee) in 60 out of 60 patients (100%), at 6 hours revealed a score of 2 (almost complete block – unable to move feet only) in 44 out of 60 patients (73.3%) and 3 (partial block – able to move knees) in 16 out of 60 patients (26.7%) and at 8 hours revealed a score of 3 (partial block – able to move knees) in 29 out of 60 patients (48.3%) and 4 (detectable weakness of hip flexion while supine, full flexion of knees) in 31 out of 60 patients (51.7%). The incidence of first dose of rescue analgesia (inj.Tramadol 50 mg iv) at 9 to 10 hours in 48.3%(29 out of 60 patients) and at 10 to 11 hours is 51.7% (31 out of 60 patients). Mean Total rescue analgesic dosage was 120 mg of inj.Tramadol and mean number of doses required was 2.2. One patient got seizure following the block and one patient developed hematoma at the injection site postoperatively both treated conservatively. Five patients had nausea and vomiting treated with inj.ondensetron 0.15 mg/kg i.v. Conclusion: This study concluded that skillful application of psoas compartment bock by posterior approach and proximal sciatic nerve block provides adequate intraoperative analgesia for major lower extremity procedures

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