The Effect of PPB Using 10, 20 and 30 ml of Lidocaine, Study on Volunteers

Study Overview
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Brief Summary
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The aim of this study is to evaluate the Popliteal Plexus Block (PPB) effect on motor nerve branches of the sciatic and femoral nerve, when using different volumes of local anesthetics for PPB. The hypothesis is that increasing the volume of anesthetics used for PPB will spread to the sciatic nerve leading to a reduced muscle strength in the lower leg and decreased nerve conduction velocity in the nerve to gastrocnemius muscle (the tibial nerve) and the nerve to anterior tibial muscle (the deep fibular nerve). The effects will be evaluated by maximum voluntary isometric contraction (MVIC) of the lower leg muscles and by recordings of the compound muscle action potential (cMAP) of the gastrocnemius and tibialis anterior muscles - a motor nerve conduction study. In addition, evaluation of PPBs effect on the femoral nerve is done by MVIC of the quadriceps femoris muscle, cMAP of the vastus medialis and vastus lateralis muscles and by a sensory nerve conduction study of the saphenous nerve.

Detailed Description
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A total number of 40 volunteers will be enrolled in the study. Each volunteer will receive two peripheral nerve blocks (one in each leg) on the day of participation. This will result in 80 peripheral nerve blocks. The types of nerve blocks given to each leg on each volunteer will depend on randomization. The 80 nerve blocks are divided into five groups specified by type of nerve block, volume of anesthetic used, and respective numbers of legs used in the group. The groups and specifications are listed here: Groups name, type of peripheral nerve block, study medication dosage and number of legs in the group: Group A: PPB with 10 ml of lidocaine 1%, 20 legs. Group B: PPB with 20 ml of lidocaine 1%, 20 legs. Group C: PPB with 30 ml of lidocaine 1%, 20 legs. Group FNB: FNB with 20 ml of lidocaine 1%, 10 legs. Group SNB: SNB with 20 ml of lidocaine 1%, 10 legs. Group FNB of SNB are performed unblinded and works as active comparatives for model control, in order to establish reference points for when a nerve is considered affected. Prior to nerve block procedure , pre block assessments are obtained in the following order: Sensory test of the saphenous nerve. MVIC by ankle plantarflexion. MVIC by ankle dorsiflexion. MVIC by knee extension. Compound muscle action potential (cMAP) recordings in the following order: Nerve to vastus medialis muscle Nerve to vastus lateralis muscle Nerve to tibialis anterior muscle Nerve to gastrocnemius muscle 60 minutes after the block performance, post block assessments are done. Values are obtained in the same order as for the pre block assessments. A peripheral intravenous line is inserted prior to the procedure of the peripheral nerve block is performed. At the discretion of the anesthetist, up to 20 mg Propofol IV may be provided to ease the patient during the nerve block procedure. The volunteer is monitored with continuous electrocardiography and pulse oximetry for the first 30 minutes after block performance and clinically hereafter. Final check by an investigator to ensure the volunteer is ready to go home. If the muscle strength is reduced, the volunteer will not be sent home before the ability to walk safely with crutches is ensured.

Official Title
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The Effect of the Popliteal Plexus Block on the Motor Function of the Leg - a Randomized, Controlled, Blinded Study in Volunteers

Conditions
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Knee Arthritis, Anesthesia, Local, Post Surgical Pain

Intervention / Treatment
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* Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]
* Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]
* Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]
* Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]
* Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA 1-2 Ability to give their written informed consent to participating in the study after having fully understood the contents of the study Exclusion Criteria: Subjects who cannot cooperate with the study. Subjects who cannot understand or speak Danish. Subjects with allergy to the medicines used in the study. Subjects suffering from alcohol and/or drug abuse - based on the investigator's opinion. Pathology or previous surgery to the lower limb. Intake of any analgesics 24 hours prior to baseline measurements. BMI > 30 Pregnancy status, provided by the volunteer.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: A person, not otherwise involved in the study will perform a randomization list. The list will contain the ID number (1-40), assigned group and type of nerve block and volume of Lidocaine 1% to be administered for nerve block, e.g. ID nr. 1: Right leg = Group A, PPB with 10 ml of lidocaine 1% Left leg = Group SNB, SNB with 20 ml of lidocaine 1% Randomization must ensure that the legs of a volunteer cannot be assigned to the same group. Groups name, type of peripheral nerve block, study medication dosage and number of legs in the group: Group A: PPB with 10 ml of lidocaine 1%, 20 legs. Group B: PPB with 20 ml of lidocaine 1%, 20 legs. Group C: PPB with 30 ml of lidocaine 1%, 20 legs. Group FNB: FNB with 20 ml of lidocaine 1%, 10 legs. Group SNB: SNB with 20 ml of lidocaine 1%, 10 legs.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group A<br>Popliteal Plexus Block given with 10 ml of Lidocaine Hydrochloride 10 mg/ml | Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]<br>* Ultrasound-guided Popliteal Plexus Block using 10 ml of of Lidocaine Hydrochloride 10 mg/ml<br>* Other names: Popliteal Plexus Block;|
| Experimental: Groups B<br>Popliteal Plexus Block given with 20 ml of Lidocaine Hydrochloride 10 mg/ml | Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]<br>* Ultrasound-guided Popliteal Plexus Block using 20 ml of of Lidocaine Hydrochloride 10 mg/ml<br>* Other names: Popliteal Plexus Block;|
| Experimental: Group C<br>Popliteal Plexus Block given with 30 ml of Lidocaine Hydrochloride 10 mg/ml | Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]<br>* Ultrasound-guided Popliteal Plexus Block using 30 ml of of Lidocaine Hydrochloride 10 mg/ml<br>* Other names: Popliteal Plexus Block;|
| Active Comparator: Group FNB<br>Femoral Nerve Block given with 20 ml of Lidocaine Hydrochloride 10 mg/ml | Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]<br>* Ultrasound-guided Femoral Nerve Block using 20 ml of of Lidocaine Hydrochloride 10 mg/ml. Is used to find cut-off values that define affection of the femoral nerve.<br>* Other names: Femoral Nerve Block;|
| Active Comparator: Groups SNB<br>Sciatic Nerve Block given with 20 ml og Lidocaine Hydrochloride 10 mg/ml | Drug: Lidocaine Hydrochloride 10 MG/ML [Xylocaine]<br>* Ultrasound-guided Sciatic Nerve Block using 20 ml of of Lidocaine Hydrochloride 10 mg/ml. Is used to find cut-off values that define affection of the sciatic nerve.<br>* Other names: Sciatic Nerve Block;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MVIC (Maximum Voluntary Isometric Contraction) ankle plantarflexion | Difference between group A, B and C in post block MVIC by ankle plantarflexion, expressed as percentage change of the pre block value. MVIC is measured using a handheld dynamometer. | Measured pre block and at 60 minutes post block | 
| MVIC ankle dorsiflexion | Difference between group A, B and C in post block MVIC by ankle dorsiflexion, expressed as a percentage change of the pre block value. MVIC is measured using a handheld dynamometer. | Measured pre block and at 60 minutes post block | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MVIC knee extension | Difference between group A, B and C in post block MVIC by knee extension, expressed as a percentage change of the pre block value. MVIC is measured using a handheld dynamometer. | Measured pre block and at 60 minutes post block | 
| cMAP (compoud motor action potention) gatrocnemius | Difference between group A, B and C, in the number of volunteers with affected cMAP of the gastrocnemius muscle, defined as sufficient change from pre block to post block. Cut-off value for sufficient change is determined by SNB group. cMAP is recorded using a motor nerve conduction study. | Measured pre block and at 60 minutes post block | 
| cMAP tibialis anterior | Difference between group A, B and C, in the number of volunteers with affected cMAP of the tibialis anterior muscle, defined as sufficient change from pre block to post block. Cut-off value for sufficient change is determined by SNB group. cMAP is recorded using a motor nerve conduction study. | Measured pre block and at 60 minutes post block | 
| cMAP vastus medialis | Difference between group A, B and C, in the number of volunteers with affected cMAP of the vastus medialis muscle, defined as sufficient change from pre block to post block. Cut-off value for sufficient change is determined by FNB group. cMAP is recorded using a motor nerve conduction study. | Measured pre block and at 60 minutes post block | 
| cMAP vastus lateralis | Difference between group A, B and C, in the number of volunteers with affected cMAP of the vastus lateralis muscle, defined as sufficient change from pre block to post block. Cut-off value for sufficient change is determined by FNB group. cMAP is recorded using a motor nerve conduction study. | Measured pre block and at 60 minutes post block | 
| Saphenus senory test | Difference between group A, B and C in the number of volunteers with an affected sensory of the saphenous nerve, defined as change, from pre block to post block, in the volunteers ability to discriminate cold in the cutaneous area innervated by the medial crural cutaneous branches of saphenous nerve. | Measured pre block and at 60 minutes post block |