Thermal QST for Interscale Block Evaluation

Study Overview
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Brief Summary
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Thermal quantitative sensory testing (QST) is a method to evaluate peripheral nerve blocks in a quantitative way. It assesses the neurosensory effects of local anesthetics, like nerve block intensity, duration, recovery, neurotoxicity, the effect of spread of local anesthetic solutions and the effect and the eventual neurotoxicity of adjuvants. We aimed at investigating, in a quantitative way, the block characteristics of 3 different commonly used local anesthetics on peripheral nerves through the application of thermal QST by measuring changes in sensory detection thresholds. Furthermore, we wanted to evaluate if QST could be of value for measuring gradual changes in block characteristics on the adjacent nerves at distance of the injection site in an US-ISB.

Official Title
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Thermal Quantitative Sensory Testing as a Method to Semi-quantitatively Assess the Neurosensory Effects of 3 Local Anesthetic Solutions in an Interscalene Block

Conditions
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Anesthetics, Local, Nerve Block

Intervention / Treatment
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* Procedure: Interscalene block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients scheduled for diagnostic and therapeutic shoulder arthroscopy, with or without decompression technique were eligible Exclusion Criteria: contraindications for ISB diabetes mellitus peripheral neuropathy patients receiving chronic analgesic therapy contraindications for NSAID patients with an initial QST with abnormal values

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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No

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Levobupivacaine 0,5%<br>Levobupivacaine 0,5% 15 ml once | Procedure: Interscalene block<br>* An ultrasound guided ISB was performed with injection aimed to block the C5-root<br>|
| Active Comparator: Levobupivacaine 0,5% with epinephrine<br>Levobupivacaine 0,5% with 1/200000 epinephrine 15 ml once | Procedure: Interscalene block<br>* An ultrasound guided ISB was performed with injection aimed to block the C5-root<br>|
| Active Comparator: Ropivacaine 0,75%<br>Ropivacaine 0,75% 15 ml once | Procedure: Interscalene block<br>* An ultrasound guided ISB was performed with injection aimed to block the C5-root<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Presence of sensory block |  | 24 hours after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Degree of sensory stimulus detection threshold variation from baseline values | The higher the difference in detection threshold variation, the more intense the block. Measured as % change, where 100% change means no sensation on maximal QST stimulus (0°C for cold sensation and 50°C for warm sensation) | 24 hours after intervention | 
| Block duration |  | 24 hours after intervention | 
| Use of rescue medication |  | 24 hours after intervention | 
| Presence of motor block |  | 24 hours after intervention |