Effect of Preoperative Continuous Femoral Nerve Block in Ease of Administration of Spinal Anaesthesia for Fracture Neck of Femur Stabilisation: A Case-control Study

Abstract

Introduction: Subarachnoid block remains the anaesthesia modality of choice for surgical fixation of femur. Extreme fracture pain makes ideal positioning for spinal anaesthesia difficult. Preoperative continuous femoral block can provide analgesia for such patients. Aim: To evaluate the effect of continuous femoral nerve block in ease of administration of spinal anaesthesia for fracture neck of femur stabilisation. Materials and Methods: This was a prospective case-control study conducted at the Government Medical College, Kozhikode, Kerala, India from September 2020 to September 2021. Total of 86 adult patients posted for fracture femur neck stabilisation were selected and divided into two groups- group 1 and group 2. Patients in group 1, were administered ultrasound guided continuous femoral nerve block with 0.2% ropivacaine (15 mL) followed by subarachnoid block and group 2 patients were administered subarachnoid block without prior femoral nerve block. Parameters observed included were VAS score while positioning for spinal anaesthesia, ease of palpating interspinous space, time required to perform spinal anaesthesia, number of attempts required to achieve dural puncture, patient satisfaction score as well as haemodynamic and respiratory changes while positioning for subarachnoid block. Results: Group 1 patients had significantly lower VAS scores while positioning for spinal anaesthesia (4.2±1.8 in group 1 as compared to 6.3±1.2 in group 2, p-value=0.001). There was a significant difference in the number of attempts required for dural puncture (1.3±0.4 in group 1 as compared to 1.8±0.6 in group 2, p-value=0.04) and total performance time for spinal anaesthesia (2.2±0.4 min in group 1 as compared to 3.3±0.9 in group 2, p-value=0.02) between 2 groups. Patient satisfaction scores were significantly higher in group 1 compared to group 2 (9.3±0.6 in group 1 as compared to 6.5±0.5, p-value <0.001). Both groups were comparable in terms of ease of palpating inter spinous space, haemodynamic and respiratory changes during positioning for subarachnoid block. Conclusion: Preoperative administration of continuous femoral nerve block provides better conditions for performing subarachnoid block in fracture neck of femur surgeries by reducing the pain while positioning.