Ultrasound Plus Nerve Stimulator Versus Nerve Stimulator Guided Lumbar Plexus Block

Summary

Ultrasound imaging, an effective tool to localize peripheral nerves, may facilitate block performance. It allows direct visualization of nerve structures, needle guidance in real-time to the target, and observation of local anesthetic diffusion. Some case series have demonstrated significantly faster onset time for interscalene blocks, supraclavicular blocks and axillary brachial plexus blocks under ultrasound than with conventional techniques. Ultrasound guidance also enhances the quality of popliteal sciatic nerve block at the popliteal fossa compared with single injection, nerve stimulator-guided block using either a tibial or peroneal endpoint. Despite this impressive profile, the application of the ultrasound for lumbar plexus blocks has not been studied extensively. It is likely that lumbar plexus block (LPB) combined with either a sciatic nerve block or sedation or both is equivalent to general anesthesia and neuraxial anesthesia for knee arthroscopy. The lumbar plexus block is traditionally performed using surface anatomical landmarks and nerve stimulation. Ultrasound imaging of the anatomy relevant for LPB is challenging because of its deep anatomic location and the "acoustic shadow" of the overlying transverse processes. Recently, Karmakar M.K. etc. has demonstrated that a paramedian transverse scan (PMTS) of the lumbar paravertebral region with the ultrasound beam being insonated through the intertransverse space (ITS) and directed medially toward the intervertebral foramen (PMTS-ITS) may overcome the problem of the "acoustic shadow" and allow clear visualization of the anatomy relevant for LPB. However, the application of a PMTS-ITS used for lumbar plexus blocks has not been studied extensively and its advantages are not validated in a clinical study. Thus, we designed this prospective, randomized, subject and assessor blinded, parallel-group, active-controlled study to compare a PMTS ultrasound-guided lumbar plexus block combined with nerve stimulation and a conventional technique on time required to readiness for surgery in patients undergo knee arthroscopy surgery.

Conditions

• Knee Arthroscopy Surgery

Interventions

PROCEDURE

Ultrasound and nerve stimulator guided lumbar plexus block

An insulated nerve block needle connected to a nerve stimulator that was delivering a current of 1.5 mA at a frequency of 2 Hz was then inserted in the long axis (in- plane) of the ultrasound transducer towards the the hypoechoic psoas compartment. If the quadriceps contraction which produces patella twitching was elicited with an initial current of 1.5mA,then the current should be reduced until contraction is still present between 0.3 to 0.5 mA .Afterward, the lumbar plexus nerve block was performed by using 30mL of 0.5% ropivacaine. Contraction should stop below a current of 0.3mA, otherwise intraneural needle position should be suspected.

PROCEDURE

Nerve stimulator guided lumbar plexus block

The block was conducted following traditional Winnie approach. The accepted end point for the lumbar plexus is stimulation of the femoral nerve component, observed by contraction of the quadriceps muscle. Quadriceps contraction which produces patella twitching should be sought with an initial current of 1.5mA, and once elicited the current should be reduced until contraction is still present between 0.3 to 0.5 mA. Afterward, the lumbar plexus nerve block was performed by using 30mL of 0.5% ropivacaine. Contraction should stop below a current of 0.3mA, otherwise intraneural needle position should be suspected.

Sponsors & Collaborators

• Huazhong University of Science and Technology

  lead OTHER

Principal Investigators

• Wei Mei, MD., PhD. · Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology

• Yuke Tian, MD., PhD. · Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2014-01-31

Primary Completion

2014-08-31

Completion

2014-10-31

Countries

• China

Study Locations