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A 6-year-old patient is undergoing a T2-pelvis posterior spinal fusion for neuromuscular scoliosis due to Duchenne's Muscular Dystrophy. During the placement of pedicles screws under fluoroscopic guidance, there is an 80% decrease in amplitude of transcranial motor evoked potentials diffusely. The patient is currently under propofol anesthesia and the mean arterial pressure is 55 mm Hg. What is the best course of action?
Proceed with instrumentation
Remove the pedicle screw and repeat testing
Switch to halogenated gas anesthesia
Restore MAP to >90 mm Hg and repeat testing
Perform a Stagnara Wake-up test
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Which of the following statements regarding Somatosensory Evoked Potenitals (SSEPs) as a method to detect neurologic injury during spinal deformity surgery is true?
SSEPs are not reliable with respect to monitoring the integrity of the anterior spinal cord pathways
The minimum criteria for determining potentially significant SSEP changes include a 10% decrease in amplitude, and a 50% increase in latency.
Signal initiation is performed with transcranial stimulation of the somatosensory cortex
SSEPs are more sensitive to the effect of anesthesia than MEPS (motor-evoked potentials)
They monitor the integrity of the anterior spinothalamic tract
A 75-year-old female with cervical spondylotic myelopathy is undergoing a cervical corpectomy with placement of an interbody cage as seen in Figure A. Immediately following placement of the cage, there is a 75% decrease in the lower extremity somatosensory evoked potentials (SSEPs) and a loss in the motor-evoked potentials (tceMEPs). What is the next most appropriate step in management?
Proceed with placing an anterior plate as planned
Correct the kyphotic deformity by placing a larger interbody strut cage
Remove strut cage and monitor for return of motor and sensory signals.
Observe for 20 minutes and then repeat motor and sensory neurophysiologic testing
Close the wound and proceed with an emergency MRI