Free CNIM Neurosurgery Questions and Answers

Question 1

What is the primary purpose of intraoperative neurophysiological monitoring (IONM) during neurosurgery?

Accepted Answer

To monitor neural pathways and prevent damage to the nervous system

Answer

Transcranial motor evoked potentials (TcMEPs) are a key IONM modality used to assess the integrity of descending motor pathways. This involves stimulating the motor cortex of the brain and recording the resulting muscle responses, providing direct information about the functional status of the motor cortex, brainstem, spinal cord, and peripheral nerves. This helps detect potential injury to these pathways during surgery.

Question 2

Which modality of IONM is commonly used to assess the integrity of motor pathways?

Accepted Answer

Transcranial motor evoked potentials (TcMEPs)

Answer

Somatosensory evoked potentials (SSEPs) monitor the integrity of sensory pathways from the periphery to the sensory cortex. A significant and sustained drop in SSEP amplitude or an increase in latency during surgery is a critical warning sign. It typically indicates potential compromise, such as ischemia, compression, or direct injury, to the neural pathway being monitored, alerting the surgical team to a possible neurological deficit.

Question 3

What does a significant drop in somatosensory evoked potentials (SSEPs) during surgery typically indicate?

Accepted Answer

Potential neural pathway compromise

Answer

Transcranial electrical stimulation for TcMEP monitoring involves applying electrical current to the scalp, which carries risks for certain patients. Patients with cardiac pacemakers or other implanted electronic devices are at risk of device malfunction due to electrical interference. Additionally, a history of stroke or seizures can increase the risk of stimulation-induced seizures. Therefore, all these conditions are considered contraindications to ensure patient safety.

Question 4

Which of the following is a contraindication for using transcranial electrical stimulation in TcMEP monitoring?

Accepted Answer

All of the above

Answer

Total intravenous anesthesia (TIVA) is generally preferred for optimal IONM results because it has less suppressive effects on neurophysiological signals compared to inhalational anesthetics. Inhalational agents can significantly depress evoked potentials and alter EEG patterns, making it harder to interpret changes related to surgical manipulation. TIVA allows for more stable and reliable monitoring, crucial for accurate signal interpretation.

Question 5

What type of anesthesia is preferred for optimal IONM results?

Accepted Answer

Total intravenous anesthesia (TIVA)

Answer

During spine surgery, monitoring free-running electromyography (EMG) continuously assesses the electrical activity of muscles innervated by nerve roots or peripheral nerves. Spontaneous bursts of EMG activity, known as neurotonic discharges, can indicate mechanical irritation, compression, or stretching of the nerve root. This provides a real-time warning to the surgeon about potential nerve injury, allowing for immediate corrective action.

CNIM - Certification for Neurophysiological Intraoperative Monitoring Practice Test

CNIM - Certification for Neurophysiological Intraoperative Monitoring Practice Test

Free CNIM Neurosurgery Questions and Answers