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Three Part Question

In [adults requiring a femoral nerve block] does [ultrasound guidance or use of anatomical landmarks] provide [better analgesia]?

Clinical Scenario

You see an elderly lady who has sustained a fractured neck of femur and remains in discomfort following administration of opiates. You wish to perform a femoral nerve block. The department's ultrasound machine is currently in use and there is no nerve stimulator. You wonder how successful a nerve block guided by anatomical landmarks will be, or whether you should wait for the ultrasound machine to be free.

Search Strategy

Medline 1950 to date, EMBASE 1974 to date, Cochrane library performed 29.04.08
Medline; [Nerve block OR femoral nerve] AND ultrasound, ltd to human and clinical trials.
EMBASE; [Nerve block OR femoral nerve OR peripheral nerve] AND ultrasound, ltd to human and clinical trials.
Cochrane; Femoral nerve blocks AND ultrasound

Search Outcome

Medline; 58, EMBASE; 77, Cochrane 15, (8 reviews and 7 trials), titles and abstracts screened to reveal one review protocol of relevance which is not yet complete.

Comment(s)

There are many trials which compare efficacy of femoral nerve blocks under ultrasound guidance vs. nerve stimulator but none that directly compare an approach via anatomical landmarks ie the inguinal ligament and the femoral pulse vs. ultrasound. Emergency departments vary in the equipment they have available often restricting the use of ultrasound. If a significant difference was found departments may have a stronger business case for such equipment.

Clinical Bottom Line

There is no evidence directly comparing femoral nerve blocks under ultrasound guidance vs. anatomical land marks. Clinicians should employ a method with which they feel comfortable and have the equipment to facilitate.