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

Duration of Subgluteal Sciatic Nerve Block After Intra- or Perineural Injection of Mepivacaine: a Randomized, Controlled Trial

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.

Study Overview

• Status: Completed
• Conditions: Postoperative Pain; Orthopedic Surgical Procedures
• Intervention / Treatment: Procedure: Perineural Injection for Subgluteal Sciatic Nerve Block; Procedure: Femoral Nerve Block; Procedure: Patient-controlled postoperative analgesia; Drug: Mepivacaine; Procedure: Intraneural Injection for Subgluteal Sciatic Nerve Block

Detailed Description

This randomized, controlled trial will investigate prospectively for differences in sensory and motor block duration after intra- or perineural injection of 1.5% (wt/vol) mepivacaine, a short-acting local anesthetic.

• Study Type: Interventional
• Enrollment (Actual): 120
• Phase: Phase 4

Contacts and Locations

Study Locations

• Italy
  • PR
    • Parma, PR, Italy, 43126
      • Anesthesia, Critical Care and Pain Medicine - University of Parma

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Undergoing non-emergent orthopedic procedure of knee, leg, foot with thigh tourniquet
• ASA Physical Status Class I-III
• Consenting to surgery under peripheral nerve block anesthesia (sciatic + femoral/saphenous block)

Exclusion Criteria:

• Unable to understand or communicate for the purpose of the study
• Exhibiting signs of neuropathy in the ipsilateral extremity
• Inability to satisfactorily image the sciatic nerve in the opinion of the attending anesthesiologist

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Perineural; Patients in this group will receive a perineural injection of mepivacaine for subgluteal sciatic nerve block, in addition to a femoral nerve block and patient-controlled postoperative analgesia.	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.; Other Names: Injection outside the common investing external layer; Epineural injection; Extraneural injection; 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.; Other Names: PCA; PCIVA; PCCPNB; Patient-controlled continuous peripheral nerve block; Drug: Mepivacaine; Thirty milliliters of 1.5% (wt/vol) mepivacaine will be used for the sciatic nerve block.; Other Names: Local Anesthetic; Carbocaine
Experimental: Intraneural; Patients in this group will receive an intraneural injection of mepivacaine for subgluteal sciatic nerve block, in addition to a femoral nerve block and patient-controlled postoperative analgesia.	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.; Other Names: PCA; PCIVA; PCCPNB; Patient-controlled continuous peripheral nerve block; Drug: Mepivacaine; Thirty milliliters of 1.5% (wt/vol) mepivacaine will be used for the sciatic nerve block.; Other Names: Local Anesthetic; Carbocaine; 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.; Other Names: Injection beneath the common investing external layer; Subepineural Injection; Gluteal sciatic nerve block; Subparaneural injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Differences in Time to Resolution of Sciatic Nerve Block	The time at which sensory and motor function of the sciatic nerve have recovered at least to the following criteria: Sensory: patients feel discomfort when pricked with a thin needle (25G); Motor: patients may move both toes and ankle, albeit with reduced strength This outcome measure will be examined by an investigator every 30-60 min and reported by patients as "time to return of sensation and movement". The investigator-reported value will be preferred if both are available.	<12 h

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Block Onset Time	Time to onset of sciatic nerve anesthesia, defined as meeting at least the following criteria: Sensory: does not feel pain or discomfort when pricked with a 25G needle.; Motor: able to slightly curl toes; unable to flex the ankle.	≤30 min
Success Rate of Anesthetic Nerve Blocks	The percentage of patients who attain the criteria for block success within 30 minutes of the injeciton. Investigators will also report the percentage of patients who successfully complete surgery without significant additional analgesia (see below); this will be defined as "clinical success rate."	≤30 min
Incidence and Prevalence of Neurologic Disturbances	Patients will be interviewed at ~4 h (block resolution visit), 7 days and (if necessary) at 30 days to assess for residual neurologic disturbances in the sciatic nerve territory. The incidence/prevalence of these phenomena will be noted.	30 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Extra- vs. Intraneural Minimum Electrical Stimulation Thresholds	The minimum electrical nerve stimulation threshold will be recorded as a function of needle tip position.	(during the procedure)

Collaborators and Investigators

• Sponsor: University of Parma

Publications and helpful links

General Publications

• Benhamou D, Blonski E, Levy P, Plessis E, Chalhoub V. Ultra-long duration of a peripheral nerve block: a possible consequence of intraneural (subepineural) local anaesthetic injection. Ann Fr Anesth Reanim. 2010 Jul-Aug;29(7-8):589-91. doi: 10.1016/j.annfar.2010.05.032. Epub 2010 Jul 13.
• Nader A, Kendall MC, De Oliveira GS Jr, Puri L, Tureanu L, Brodskaia A, Asher Y, Parimi V, McCarthy RJ. A dose-ranging study of 0.5% bupivacaine or ropivacaine on the success and duration of the ultrasound-guided, nerve-stimulator-assisted sciatic nerve block: a double-blind, randomized clinical trial. Reg Anesth Pain Med. 2013 Nov-Dec;38(6):492-502. doi: 10.1097/AAP.0b013e3182a4bddf.

Study record dates

Study Major Dates

• Study Start: October 1, 2012
• Primary Completion (Actual): July 1, 2013
• Study Completion (Actual): October 1, 2013

Study Registration Dates

• First Submitted: November 4, 2013
• First Submitted That Met QC Criteria: November 4, 2013
• First Posted (Estimate): November 11, 2013

Study Record Updates

• Last Update Posted (Estimate): November 19, 2013
• Last Update Submitted That Met QC Criteria: November 18, 2013
• Last Verified: November 1, 2013

More Information

Terms related to this study

• Keywords: Ultrasonography; Anesthetics, Local; Lower Extremity; Sciatic Nerve; Anesthesia, Regional; Mepivacaine
• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Pain; Neurologic Manifestations; Pain, Postoperative; Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Mepivacaine
• Other Study ID Numbers: ANEST-ORT-03

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No