Ultrasound Guidance Versus Electrical Stimulation for Continuous Popliteal-Sciatic Nerve Blocks

Ultrasound Guidance Versus Electrical Stimulation for Continuous Popliteal-Sciatic Nerve Blocks: A Randomized, Controlled Trial

Research study to determine if pain relief following foot and/or ankle surgery is influenced by the technique used to place perineural catheter. The catheters are placed using ultrasound-guidance or nerve stimulation and the method is selected at random using a computer program. This may help to determine if one of these methods is associated with an increased success rate and incidence of foot numbness during the infusion.

Specific Aim 1: To determine the relationship between perineural catheter placement technique (ultrasound-guidance and electrical stimulation) and quality of postoperative analgesia during continuous popliteal-sciatic nerve blocks following moderate-to-severely painful orthopedic surgery.

Hypothesis 1: When inserting a perineural catheter for a continuous peripheral nerve block, the use of electrical stimulation, as compared with ultrasound-guidance, is associated with decreased pain the morning following moderate-to-severely painful orthopedic surgery as measured with a numeric rating scale.

Specific Aim 2: To determine the relationship between perineural catheter placement technique (ultrasound-guidance and electrical stimulation) and degree of sensory deficit during continuous popliteal-sciatic nerve blocks following moderate-to-severely painful orthopedic surgery.

Hypothesis 2: When inserting a perineural catheter for a continuous peripheral nerve block, the use of electrical stimulation, as compared with ultrasound-guidance, is associated with increased sensory deficit the day following moderate-to-severely painful orthopedic surgery as measured with a simple 0-10 scale (0=no numbness; 10=completely insensate) of the part of the foot with the greatest sensory deficit at the time of the data-collection phone call.

Inclusion Criteria:

• Undergoing surgery with a planned popliteal-sciatic perineural catheter for postoperative analgesia
• Expected postoperative pain to be at least moderate in severity the day following surgery (often not adequately treatable with oral analgesics alone)
• Age 18 years or older

Exclusion Criteria:

• Pregnancy
• Inability to communicate wiht the investigators and hospital staff
• Incarceration
• Current chronic opioid use (daily opioid equivalent of >10mg oxycodone for more than the previous four weeks)
• History of alcohol or opioid abuse
• Neuropathy in the surgical extremity
• Any physical, mental or medical conditions which may confound quantifying postoperative pain resulting from surgery