Duration of Analgesia After Popliteal Fossa Nerve Blockade: Effects of Dexamethasone and Buprenorphine

Duration of Analgesia After Popliteal Fossa Nerve Blockade: Effects of Dexamethasone and Buprenorphine

Patients scheduled to go home after ankle surgery at HSS typically receive a sciatic nerve block in the popliteal fossa and oral analgesic tablets (such as Percocet). Popliteal fossa nerve blockade has reduced pain for these patients (YaDeau et al, Anesth Analg 2008;106:1916-20), but unfortunately the patients still often experience moderate to severe pain after the block wears off. The investigators wish to study two additives that may prolong the period of analgesia provided by the nerve block. The additives will be studied in the context of a standardized postoperative multimodal analgesic pathway.

Primary outcome:

Does adding dexamethasone and / or buprenorphine prolong the analgesia provided by a popliteal fossa nerve block?

Inclusion Criteria:

1. Patients of Dr Levine or Dr Roberts.
2. Scheduled for discharge from HSS after foot or ankle surgery.
3. A single-injection popliteal fossa nerve block is judged appropriate.
4. Surgery confined to foot and ankle (no iliac crest bone graft planned - iliac aspirate is not an exclusion criterion).
5. Patients aged 18-75 years.

Exclusion Criteria:

• Surgery that will cause pain at sites outside the distal lower extremity (e.g. iliac crest bone graft).
• Bilateral surgery
• Chronic pain (defined as regular use of opioid analgesics for > 3 months).
• Chronic use of steroids (defined as regular use of steroids for > 3 months).
• Contraindication to performance of the popliteal fossa nerve block with 30 cc 0.25% bupivacaine with clonidine (e.g. alleged bupivacaine sensitivity, low body weight, clonidine allergy, etc.).
• Contraindications to dexamethasone or buprenorphine (e.g. allergy, Insulin Dependent Diabetes Mellitus, etc.)
• Inability of the patient to describe postoperative pain (e.g. psychiatric disorder, dementia).
• Non-English speaking patients (the questionnaire is in English, and translations would have to be separately validated)