Ultrasound Visualization Versus Electrical Nerve Stimulation

August 29, 2012 updated by: Nanette Schwann, M.D., Allentown Anesthesia Associates

Ultrasound Visualization v. Electrical Nerve Stimulation for the Safety and Effectiveness of Interscalene/Axillary Nerve Block in Upper Extremity Surgery: A Randomized Trial

Hypothesis and Specific Aims:

The investigators hypothesize that ultrasound (US) visualization is as effective as nerve stimulation (NS) for identification of peripheral nervous structures and may be associated with less trauma and patient discomfort. Specifically, the investigators believe that equivalent rates of surgical anesthesia are achievable with non-invasive ultrasonic needle guidance in comparison to needle guidance by intensity of motor fiber response to intermittent electrical nerve stimulation. Specifically, the number of needle sticks to identify the brachial plexus and total time to plexus sheath injection may be reduced while achieving similar efficacy rates. The investigators hypothesize that similar composite safety and efficacy endpoints but improved patient satisfaction and acceptance will favor US over NS guidance of nerve blocks indicated for surgery on the extremity surgery. However, the investigators believe that an economic assessment based upon capital hardware investment, operating room utilization, total block time, and pay for performance patient satisfaction metrics require examination prior to assimilation of new technology into clinical practice.

Study Overview

Detailed Description

This is a prospective randomized study of 450 consecutive patients presenting for upper extremity surgery scheduled to receive NB without general anesthesia for their surgical procedure. Patients will be randomized to receive one of two nerve localization techniques in a 1:1 randomization ratio. Primary intraoperative providers of supplemental sedative, additional local anesthetic infiltration or analgesia, general anesthesia and assessors of VAS or PCI will be blinded to the technique.

Patients over 18 years of age presenting for elective upper extremity surgery planned in the supine position under isolated interscalene or axillary nerve block will be screened. Up to 450 patients undergoing unilateral upper extremity procedures at Lehigh Valley Hospital will be enrolled.

STUDY PROCEDURES Screening:

All patients meeting inclusion criteria and not meeting exclusion criteria will be eligible to be enrolled. All subjects who have preadmission testing will be recruited prior to their surgical procedure with initial contact made before the day of their scheduled surgery. For patients who do not have preadmission testing scheduled and are found to be eligible for the study on the day of surgery, those patients will be consented for the study the morning of their procedure by the study anesthesiologist. Only patients who are able to understand English and who are able to legally give written informed consent will be recruited to the study. Following signed informed consent (IRB approved) and permission of their surgeon and anesthesiologist and prior to the start of anesthesia, vital signs, standard lab tests, patient history and physical examination will be reviewed.

Day of Procedure:

For the NS group, interscalene/axillary block will be performed in the standard method using a nerve stimulator attached to a four centimeter Stimuplex (B Braun) needle. Following application of routine monitors, supplemental oxygen via facemask, and intravenous sedation, the skin overlying the brachial plexus will be anesthetized. The Stimuplex needle will then be inserted and guided into a position in close proximity to the brachial plexus using an endpoint of muscle twitches involving the hand at a stimulus intensity of less than 0.5 milliamps to the satisfaction of the operator. Forty (40) milliliters of 0.5 percent Bupivicaine with 1.5% Mepivicaine with 1:200,00 of epinephrine will be injected incrementally with intermittent aspiration. This block is chosen for the study because of its widespread use for a variety of shoulder procedures and for its low incidence of complications. The quoted success rate in the literature for interscalene block ranges from 70 to 95 percent.

For the US group interscalene block will be performed in a method using ultrasound guided needle insertion. Following application of routine monitors, supplemental oxygen via facemask, and intravenous sedation, the skin overlying the brachial plexus will be anesthetized. A sterile cover will be used for the ultrasound probe. Using this probe, the anesthesiologist can visualize the nerve and will maneuver the tip of the needle into the nerve guided by the of ultrasound probe. Forty (40) milliliters of 0.5% Bupivicaine with 1.5% Mepivicaine with 1:200,00 of Epinephrine will be injected incrementally with intermittent aspiration. This block is chosen for the study because of its widespread use for a variety of shoulder procedures and for its low incidence of complications. The quoted success rate in the literature for interscalene block ranges for 70 to 95 percent.

The brachial plexus will be visualized at the level of the roots of the plexus at this level. Presence or absence of local anesthetic around the nerves will be recorded using a Sonosite Titan T-shaped ultrasound probe placed on the patient's skin. Still images of the brachial plexus and the local anesthetic will be captured for each patient. Patient identifiers will be on the images, however the images are placed on the patient's medical record.

Assessment of block success:

The success of the block will be assessed by examining motor strength in the anesthetized extremity and degree of anesthesia at 30 minutes after injection. Strength in the distribution of the musculocutaneous, median, radial, and ulnar nerves will be assessed. Pinprick and cold sensation will be assessed in the same distributions. A successful block will be one with a lack of sensation to cold and pinprick in the above distributions as well as strength less than three out of five on the standard scale of strength testing in all of the above distributions. Ultimately, block success (yes/no) will be determined by pain free surgery not requiring general anesthesia. The patient comfort index and post op assessments will be carried out as above.

Completion of the Study:

The study will be complete at PACU discharge after the patient returns his/her assessment of PCI and pain and nausea data.

Study Type

Interventional

Enrollment (Actual)

158

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Pennsylvania
      • Allentown, Pennsylvania, United States, 18105
        • Lehigh Valley Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

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:

  • Male or female patients older than 18 years of age at the time of screening
  • ASA Class I - IV, undergoing unilateral elective surgical procedure involving the shoulder, arm, elbow, forearm, or hand
  • Planned interscalene block

Exclusion Criteria:

  • Peripheral neuropathy
  • Coagulopathy
  • Anticoagulant treatment that would preclude regional anesthesia
  • Local anesthetic allergy
  • Infection at the site of injection

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Ultrasound
Ultrasound guided nerve localization through direct visualization of the nerves and surrounding structures.
Ultrasonography will allow direct visualization of nerves. As local anesthetic is injected, it can be seen surrounding the nerve.
Other Names:
  • Sonosite Titan T-shaped ultrasound probe
Active Comparator: Nerve Stimulation
Standard of Care

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of Successful Block: defined by avoidance of General Anesthesia (which will be documented in the medical record as such)
Time Frame: 30 minutes after injection
30 minutes after injection

Secondary Outcome Measures

Outcome Measure
Time Frame
Amount of sedation required for block. (mg of drug)
Time Frame: 30 minutes after injection
30 minutes after injection

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Collaborators

Investigators

  • Principal Investigator: Nanette Schwann, M.D., Allentown Anesthesia Associates

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 2009

Primary Completion (Actual)

March 1, 2010

Study Completion (Actual)

October 1, 2011

Study Registration Dates

First Submitted

November 9, 2009

First Submitted That Met QC Criteria

November 9, 2009

First Posted (Estimate)

November 10, 2009

Study Record Updates

Last Update Posted (Estimate)

August 30, 2012

Last Update Submitted That Met QC Criteria

August 29, 2012

Last Verified

August 1, 2012

More Information

Terms related to this study

Other Study ID Numbers

  • UVVENS

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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