Determination of Target of Adequate Partial Neuromuscular Blockade for Electrophysiologic Monitoring During Microvascular Decompression Surgery

Study Overview
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Brief Summary
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There have been reports of monitoring LSR during MVD surgery helps predicting the clinical outcome of MVD.However, there have been no evidence of which degree of partial neuromuscular blockade should be performed or no neuromuscular blockade could be performed during LSR monitoring. Therefore, we performed a randomized controlled trial to evaluate the effect of different degree of partial neuromuscular blockade, including no neuromuscular blockade on the LSR monitoring for MVD surgery.

Detailed Description
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Hemifacial spasm develops by vascular compression of facial nerve at the root exit zone from brain stem. Microvascular decompression (MVD) is known for its curative treatment. Lateral spread response (LSR) is a kind of pathologic electromyographic (EMG) wave form which develops when facial nerve is compressed by vessel. There have been reports of monitoring LSR during MVD surgery helps predicting the clinical outcome of MVD. As neuromuscular blockade during LSR monitoring decreases the amplitude of EMG, partial neuromuscular blockade is usually maintained during general anesthesia for MVD. However, there have been no evidence of which degree of partial neuromuscular blockade should be performed or no neuromuscular blockade could be performed during LSR monitoring. Therefore, we performed a randomized controlled trial to evaluate the effect of different degree of partial neuromuscular blockade, including no neuromuscular blockade on the LSR monitoring for MVD surgery.

Official Title
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Determination of Target of Adequate Partial Neuromuscular Blockade for Electrophysiologic Monitoring During Microvascular Decompression Surgery

Conditions
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Hemifacial Spasm, Microvascular Decompression, Lateral Spread Response Monitoring

Intervention / Treatment
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* Other: TOF count-guided partial NMB
* Other: T1/Tc guided partial NMB
* Other: No NMB


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Those who undergo microvascular decompression by diagnosis of hemifacial spasm in our institution Exclusion Criteria: Patients were excluded from the study if they had any of following: severe cardiopulmonary disorder with hemodynamic unstability (pulmonary hypertension, cardiomyopathy, mechanical ventilation, American Society of Anesthesiologists physical status III or more), severe hepatic or renal disease. Those who can not undergo MEP monitoring due to central or peripheral neuromuscular disease, e.g. cerebral palsy, myasthenia gravis, acute spinal injury, neurologic shock

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 70 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: TOF count-guided group<br>Using partial neuromuscular blockade to maintain train-of-four response of two, TOF response measured by the neuromuscular transmission module (NMT module) | Other: TOF count-guided partial NMB<br>* Using partial neuromuscular blockade to maintain train-of-four response of two, TOF response measured by the neuromuscular transmission module (NMT module)<br>|
| Active Comparator: T1/Tc amplitude group<br>Using partial neuromuscular blockade to maintain T1/Tc amplitude of 50%, T1/Tc amplitude measured by the neuromuscular transmission module (NMT) | Other: T1/Tc guided partial NMB<br>* Using partial neuromuscular blockade to maintain T1/Tc amplitude of 50%, T1/Tc amplitude measured by the neuromuscular transmission module (NMT)<br>|
| Experimental: No neuromuscular blockade group<br>to maintain no neuromuscular blockade during LSR monitoring except the intubation dose during anesthetic induction | Other: No NMB<br>* to maintain no neuromuscular blockade during LSR monitoring except the intubation dose during anesthetic induction<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lateral spread response | Lateral spread response of electromyography measured by electrophysiologist at baseline (30 min after anesthetic induction) | baseline (30 min after anesthetic induction) | 
| Lateral spread response | Lateral spread response of electromyography measured by electrophysiologist before dura opening | before dura opening (45 minute after anesthetic induction) | 
| Lateral spread response | Lateral spread response of electromyography measured by electrophysiologist after dura opening (one hour after anesthetic induction) | after dura opening (60 min after anesthetic induction) | 
| Lateral spread response | Lateral spread response of electromyography measured by electrophysiologist before facial nerve decompression (90 minutes after anesthetic induction) | before facial nerve decompression (90 minutes after anesthetic induction) | 
| Lateral spread response | Lateral spread response of electromyography measured by electrophysiologist after facial nerve decompression (2 hour after anesthetic induction) | after facial nerve decompression (120 min after anesthetic induction) | 
| Lateral spread response | Lateral spread response of electromyography measured by electrophysiologist after dura closure (150 min after anesthetic induction) | after dura closure (150 min after anesthetic induction) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Train-of-four response | Train-of-four response to ulnar nerve electrical stimulation measured by NMT module at six time-points; Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | 
| T1/Tc amplitude | T1/Tc amplitude as a reponse to ulnar nerve stimulation measured by NMT module at six time points; Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | 
| incidence of patients' spontaneous movements or respiration | incidence of patients' spontaneous movements or respiration measured by anesthesiologists or reported by surgeon at six time points; Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | 
| Mean blood pressure (mmHg) | mean blood pressure measured by anesthesiologists at six time points; Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | 
| heart rate (beats/min) | heart rate measured by anesthesiologists at six time points; Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | 
| pulse oximetry (oxygen saturation, %) | pulse oximetry measured by anesthesiologists at six time points; Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) | Baseline (30min), Before dura open (45 min), After dura open (60 min), Before decompression (90 min), After decompression (120 min), After dura close (150 min after anesthetic induction) |