A comparison of pre‐operative nerve stimulator‐guided femoral nerve block and fascia iliaca compartment block in patients with a femoral neck fracture

Abstract

SummaryWe undertook a randomised, controlled trial to compare the analgesic efficacy and opioid sparing effect of nerve stimulator-guided femoral nerve block with fascia iliaca compartment block in patients awaiting surgery for fractured neck of femur. Ten-centimetre visual analogue pain scores were measured before and 2 h after the block and opioid consumption was recorded in the 12-h period after the block. One hundred and ten patients were randomly assigned. Femoral nerve block provided superior pre-operative analgesia for fractured neck of femur compared with fascia iliaca compartment block. The difference in the mean reduction of pain score after the block was 0.9 (95% CI 0-1.8); p = 0.047. Patients receiving a femoral nerve block required less morphine after the block than those receiving fascia iliaca compartment block (p = 0.041). In the UK, the target for maximum delay from diagnosis to surgery for patients with femoral neck fracture is 36 h, during which time they require adequate analgesia. Both femoral nerve block [1] and the fascia iliaca compartment block [2] are commonly used peri-operatively for analgesia in patients with a fractured neck of femur. These two techniques are used in our institution and we have equipoise as to their relative efficacy. They are either performed with a nerve stimulator to place local anaesthetic solution close to the femoral nerve or as a fascia iliaca compartment block using surface landmarks and the tactile feedback technique. All blocks are undertaken by four specialist acute pain nurses with training and extensive experience in performing these blocks. To date, over 1600 blocks have been undertaken by this team with no significant complications recorded. The two blocks have not been compared for relative efficacy when administered pre-operatively. This study was designed to resolve the question as to which technique provides superior analgesic efficacy. MethodsThe study was approved by the Local Research Ethics Committee and written informed consent was obtained from all patients. Inclusion criteria were patients presenting with isolated femoral neck fracture who had a mini-mental score [3] of ≥ 8/10 and fulfilled the requirements for full mental capacity for

Pre‐operative femoral nerve block vs fascia iliaca block for femoral neck fracture – 6

“…We feel that Newman et al's findings [1] should be accepted with three important caveats. First, the authors did not standardise to one nerve localisation technique (anatomical landmark or nerve stimulator or ultrasound) and therefore the degree to which the observed difference occurred because of differences in technique rather than nerve anatomy cannot be quantified.…”

“…Regarding Newman et al's study [1], if 'the right amount' of local anaesthetic is injected into 'the right place' (the fascia iliaca compartment), it will spread to the femoral nerve and should produce an adequate femoral block, comparable with the femoral nerve block [2]. Larger volumes may allow spread to the other nerves in the compartment (obturator and lateral femoral cutaneous) or even the lumber plexus.…”

Pre‐operative nerve blocks for hip fracture – 1

“…We read with great interest the article by Newman et al [1]. The authors clearly have an excellent pain management team, and other hospitals should strive to provide early regional blockade as the authors have.…”

“…I congratulate Newman et al for their well-conducted study that concluded that femoral nerve blockade significantly improved pre-operative analgesia compared with fascia iliaca blockade in patients with hip fracture [1].…”

Pre‐operative femoral nerve block vs fascia iliaca block for femoral neck fracture – 4

“…Newman et al [1] have identified that peripheral nerve stimulation to assist placement of local anaesthetic close to the femoral nerve and its branches gave superior results in their hands when compared with blind placement after perceived puncture of two fascial layers. Ultrasound-assisted methods are now gaining widespread adoption as these devices become more commonly available.…”