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NCT Number: NCT01981291

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

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.

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Key information

Conditions

Orthopedic Surgical Procedures Neurologic Manifestations Pain Pain, Postoperative Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Postoperative Pain Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Anesthesia, Critical Care and Pain Medicine - University of Parma

Parma, PR, 43126, Italy

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Intraneural Injection for Subgluteal Sciatic Nerve Block

Procedure

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

Perineural Injection for Subgluteal Sciatic Nerve Block

Procedure

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

Femoral Nerve Block

Procedure

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

Patient-Controlled Postoperative Analgesia

Procedure

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

Mepivacaine

Drug

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

Other names: Local Anesthetic, Carbocaine

Primary outcomes

  1. Differences in Time to Resolution of Sciatic Nerve Block

    Time frame: <12 h

    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.

Secondary outcomes

  1. Block Onset Time

    Time frame: ≤30 min

    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.

  2. Success Rate of Anesthetic Nerve Blocks

    Time frame: ≤30 min

    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."

  3. Incidence and Prevalence of Neurologic Disturbances

    Time frame: 30 days

    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.

Other outcomes

  1. Extra- vs. Intraneural Minimum Electrical Stimulation Thresholds

    Time frame: (during the procedure)

    The minimum electrical nerve stimulation threshold will be recorded as a function of needle tip position.

Sponsors and collaborators

Lead sponsor

University of Parma

Other

Registry information

Official study title

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

Important dates

Study start
2012
Primary completion
2013
Study completion
2013
First posted
Nov 11, 2013
Registry last updated
Nov 19, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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