Analgesia for pelvic limb surgery. A review of peripheral nerve blocks and the extradural technique.

OBJECTIVES: To describe the anatomy and approaches reported for peripheral nerve blockade (PNB) of the pelvic limb in dogs and cats and to consider the role of PNB in relation to the extradural technique. DATABASES USED: This review was conducted using the terms 'nerve block', 'extradural' 'dog' and 'cat' entered into Pubmed and Google. Results were filtered manually to narrow the field to pelvic limb nerve blocks. The reference lists of retrieved papers were scrutinized to identify further studies for inclusion.
CONCLUSIONS: Successful PNB techniques require thorough anatomical knowledge for the establishment of reliable landmarks, puncture sites, the direction and depth of needle insertion, and relevant structures to be avoided. To date, clinical evaluations have been made in subjects undergoing stifle surgery where the sciatic nerve has been blocked in combination with various approaches to the femoral nerve. Currently the bulk of literature examines new approaches to these nerves and each of these is described. To date there are no veterinary studies directly comparing one approach versus another, and therefore one is unable to draw conclusions of superiority. The role of PNB's versus the extradural technique is discussed.