Anesthesia and Motor Evoked Potential (MEP) Recruitment

Study Overview
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Brief Summary
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Test the hypothesis to recruit larger motor responses to transcranial stimulation.

Detailed Description
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The study is designed to test the hypothesis that it is possible to recruit larger motor responses to transcranial stimulation by increasing the number of stimulating pulses under both baseline conditions and conditions of increased anesthetic suppression of the motor responses.

Official Title
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The Effect of Anesthesia on the Recruitment of Motor Evoked Potentials Using an Increased Number of Pulses

Conditions
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Idiopathic Scoliosis

Intervention / Treatment
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* Drug: Desflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 12 through 17 years Diagnosis of idiopathic scoliosis Scheduled for posterior spinal fusion with neurophysiological monitoring No known allergies to propofol or remifentanil No contraindication to total intravenous anesthesia No contraindications to the administration of volatile agents Exclusion Criteria: Failure to consent or assent to study Diagnosis other than idiopathic scoliosis Poorly controlled seizures or the presence of a cochlear implant Patient history or family history of malignant hypothermia or mitochondrial myopathies

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 17 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

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: desflurane MEP's<br>Transcranial motor evoked potentials are obtained under total intravenous anesthesia (TIVA) and again after desflurane at 3%, for at least 5 minutes.at two different time points. Each subject is his/her own control | Drug: Desflurane<br> <br> * Other names: Suprane;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of Pulse Train Length on Transcranial Motor Evoked Potentials (TcMEP) Area Under Total Intravenous Anesthesia (TIVA) and TIVA Plus 3% Desflurane | A series of 15 transcranial motor evoked potentials are recorded under a TIVA anesthetic and again after addition of 3% desflurane for 5 minutes at two different time points in a surgical procedure. The series consisted of 3 runs of 5,6, 7, 8, and 9 pulse trains, each train separated by 30 seconds. The 3 runs were averaged to give and average value of TcMEP amplitude and area for the 5,6,7,8 and 9 pulse trains. The data were used to compute regression coefficients for area vs pulse length for the TIVA case and TIVA plus desflurane for each participant who completed the study..The final measure is the number of participants who had a MEP area ratios significantly different from 1 at all times and conditions; that is for TIVA alone and TIVA plus desflurane, at both time points. | 15 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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anesthesia, pulses, intra, operative, neurophysiologic, monitoring, transcranial, motor, evoked, potential