Duration of Sciatic Nerve Block After Injection of Local Anesthetic In or Around the Nerve

Summary

This study was designed to assess whether the injection of local anesthetic into the nerve (intraneural), as opposed to around it (perineural), leads to longer anesthesia and analgesia of the leg.

Some reports of accidental intraneural injection mention an extremely long duration. When different drugs and doses were evaluated in a clinical trial of intraneural injection, a longer-than-expected duration was reported.

The investigators will compare the two types of injection using the same drug, so as to determine if there is an actual difference in duration.

Conditions

• Orthopedic Surgical Procedures
• Postoperative Pain

Interventions

PROCEDURE

Intraneural Injection for Subgluteal Sciatic Nerve Block

The injection will start as the needle penetrates the outermost discernible layer of the nerve (epineurium) under ultrasound guidance. The injection will be adjudicated as "intraneural" if nerve cross section expansion and a reduction in echogenicity are observed. Short-axis real-time ultrasound imaging will be used, with an in-plane needle approach.

PROCEDURE

Perineural Injection for Subgluteal Sciatic Nerve Block

The injection will start as the needle indents the outermost discernible layer of the nerve (epineurium) under ultrasound guidance. The injection will be adjudicated as "intraneural" if the drug infiltrates the space between the epimysium of the surrounding muscles and the outer epineurium of the sciatic nerve. Short-axis real-time ultrasound imaging will be used, with an in-plane needle approach.

PROCEDURE

Femoral Nerve Block

Patients will receive an ultrasound-guided femoral nerve block using a short- or long-acting local anesthetic, as deemed indicated.

PROCEDURE

Patient-controlled postoperative analgesia

Patients will receive a patient-controlled intravenous or perineural catheter-based analgesia, depending on their preference and the anesthesiologist's indication.

DRUG

Mepivacaine

Thirty milliliters of 1.5% (wt/vol) mepivacaine will be used for the sciatic nerve block.

Sponsors & Collaborators

• University of Parma

  lead OTHER

Principal Investigators

• Marco Baciarello, MD · University of Parma

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2012-10-31

Primary Completion

2013-07-31

Completion

2013-10-31

Countries

• Italy

Study Locations