Magnetic Resonance Imaging of Interscalene Plexus Block

Summary

Interscalene plexus block is a widely used technique to provide anesthesia and analgesia for surgery at the upper extremity (shoulder and upper arm); it is standard-of-care in many institutions worldwide. Local anesthetic is being injected around the nerves supplying the arm (Plexus brachialis) at a specific location in the arm (between the scalenus muscles, thus called "interscalene plexus block"). The optimal volume of injection with regard to efficacy, safety and avoidance of untoward effects has been subject to intense debate for a long time. In spite of evidence that small volumes (between 5 and 7 mls) are effective for adequate postoperative analgesia, larger volumes up to 40 mls are still frequently used in many practices. However, with the use of such large doses, adverse events are known to occur with increased frequency, including paralysis of the diaphragm or spread of local anesthetic to the spinal cord.

This study is intended to help evaluate the effects of small or larger injection of local anesthetic around the brachial plexus, and to correlate the distribution with clinical efficacy, block duration, and possible side effects. It is a randomized, controlled, observer-blinded trial; patients undergoing shoulder or upper arm surgery will be randomly allocated to receive either 5mls or 20mls of local anesthetic for their interscalene plexus block. Magnetic resonance imaging will be performed immediately afterwards, followed by a series of neurological exams during the hospital stay. Test of lung function (spirometry) and ultrasound of the diaphragm will be used to evaluate effects of the block on respiratory mechanics.

Conditions

• Disorder of Shoulder

Interventions

PROCEDURE

Interscalene Nerve Block

ultrasound guided interscalene plexus block (UISB) immediately before magnetic resonance imaging of the neck.

DRUG

Ropivacaine 0.75%, 20ml

20 ml of ropivacaine 0.75%

DRUG

Gadopentetate-Dimeglumine 0.0125 mmol

0.0125 mmol of gadopentetate-dimeglumine

DRUG

Gadopentetate-Dimeglumine 0.05 mmol

0.05 mmol of gadopentetate-dimeglumine

DRUG

Ropivacaine 0.75%, 5ml

5 ml of ropivacaine 0.75%

PROCEDURE

Shoulder Surgery

As per individual requirement (patient-dependent)

Sponsors & Collaborators

• Paracelsus Medical University

  lead OTHER

Principal Investigators

• Peter Gerner, MD · Department of Anesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University, Salzburg, Austria

• Gerhard Fritsch, MD · Department of Anesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University, Salzburg, Austria

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2013-12-31

Primary Completion

2014-07-31

Completion

2014-07-31

Countries

• Austria

Study Locations