Posterior Cervical Decompression and Fusion Clinical Trial
Official title:
Effect of Reversal of Neuromuscular Blockade on the Amplitude of Motor Evoked Potentials: A Randomized Controlled Crossover Study Comparing Sugammadex and Placebo
Intraoperative monitoring of the motor evoked potentials has been shown to be both a
sensitive and specific indicator for detecting intraoperative neurological injuries during
spine surgery.(Fehlings, Brodke et al. 2010) It is utilized whenever there is risk for injury
of nerve roots or the spinal cord during the procedure.
Anesthetic agents, especially the inhaled volatile anesthetics and muscle relaxants, are
con-founders for motor evoked potential monitoring as they have deleterious effects on the
amplitude of motor evoked potentials.(Sekimoto, Nishikawa et al. 2006) Hence, total
intravenous anesthesia with no intraoperative muscle relaxants, are the standard anesthetic
technique for these surgeries.
Muscle relaxants are usually required during the induction of anesthesia and endotracheal
intubation of larynx. Current practice is to wait for the resolution of residual
neuromuscular blockade before the motor evoked potential recordings (MEP) are initiated and
this makes it difficult to assess if there was any neurological injury associated with
positioning of the patient. A previous case series has shown that reversal of muscle relaxant
can improve the amplitude of MEPs.(Batistaki, Papadopoulos et al. 2012) The aim of this study
is to perform a randomized controlled trial to study the changes in motor evoked potential
amplitudes comparing sugammadex and placebo.
Motor evoked potential monitoring is a well-established and safe intervention to assist in
prevention of intraoperative injury during spine surgery.(Schwartz, Sestokas et al. 2011)
Patients with cervical myelopathy often present with neurological deficits and recording of
the motor evoked potentials are often challenging in these patients. In addition, anesthetic
agents especially muscle relaxants can abolish the motor response making it difficult to know
when the baseline MEP can be recorded.
The usual anesthetic practice for patients undergoing posterior cervical spine surgery is to
administer muscle relaxation to aid intubation at the start of the case . The neuromuscular
blockade is then allowed to wear off and the neurophysiologist will attempt to record their
baseline motor evoked potentials during or just prior to surgical exposure.
The issues with this current technique are;
1. Patients cannot be monitored for neurological changes during their transfer into the
prone position
2. There is likely residual neuromuscular blockade decreasing the amplitude of motor evoked
potentials.
Investigators plan to perform a randomized controlled cross-over trial comparing the change
in MEP amplitudes with administration of sugammadex or placebo. This will be performed on at
risk patients (e.g. cervical myelopathy) undergoing posterior cervical spine surgery where
MEPs can be more difficult to attain but of higher utility.
The purpose of this study is to determine if reversal of residual neuromuscular blockade with
Sugammadex can increase the amplitude of the motor evoked potentials.
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