System Architecture
Neuro-IOM system consists of electronic unit with built-in amplifiers and stimulators, several electrical stimulator pods with 5-meter connecting cables, PC, set of special electrodes and dedicated software.
16-channel Amplifier
The system is equipped with a reliable low-noise universal neurophysiological amplifier allowing high-quality acquisition of EMG, EEG and multimodal EPs. Neurosoft amplifiers are well-known around the world.
Acquisition Pods to Attach Recording Electrodes
The system is equipped with two pods with 5-meter shielded cables to attach the recording electrodes. In most cases the electrodes placed at upper extremities are connected to one pod, and at lower extremities — to another one. The signal acquisition at IOM is mostly done with the monopolar needle electrodes.
Transcranial Electrical Stimulator (TES)
Transcranial electrical stimulator is intended for stimulation of motor cortex in order to elicit motor evoked potentials in peripheral muscles. MEPs allow to monitor the integrity of motor pathways. Response acquisition is performed using one or several channels of built-in 16-channel amplifier.
TES Electronic Switch
During the monitoring it is often required to change stimulation site, for example, stimulate left or right side, arm or leg area. For this purpose a special electronic switch is built-in. It has 4 pairs ot outputs to attach the stimulating electrodes. A pair of outputs to deliver a stimulus is specified in Neuro-IOM.NET software. Special corkscrew electrodes are commonly used for the transcranial electrical stimulation.
Direct Nerve Stimulator
With a special probe a surgeon can stimulate nerves in operative area of risk. At that low current is delivered to the probe. The recording electrodes connected to 16-channel amplifier are placed on muscles innervated by nerves located in operative area. As soon as a surgeon stimulates a nerve with the probe, the system will record the obtained muscle response. Thus, a specialist will get a direct positive feedback concerning the nerve location. Using the electrophysiological data a surgeon can change the strategy in order to avoid the injury of nervous tissue. Besides, low-current stimulator can be also used during the surgical testing of pedicle screws.
Direct Nerve Stimulator Pod
The DNS pod with 5-meter cable is intended to attach different electrodes for the direct nerve stimulation. The wide range of probes can be used: concentric, monopolar, hook etc.
8-channel Electrical Stimulator
This device allows stimulating 8 nerves simultaneously or in any sequence to elicit somatosensory evoked potentials. Using 16-channel amplifier it is possible to record SSEPs obtained from various sites of peripheral nervous system along the efferent pathways. For example, to stimulate upper extremity, the median nerve is often used. At that the responses are recorded in different sites of this nerve, at Erb’s point and sensory cortex. Thus, it is possible to assess the integrity of the whole sensory tract. SSEPs are sensitive to peripheral nerve events, spinal cord pathway injuries, and also to regional blood flow changes.
Electrical Stimulator Pods (for 1-4 Channels and 5-8 Channels)
Each pod is equipped with 4 outputs to attach the stimulating electrodes. The outputs can function simultaneously. In most cases the electrodes placed at upper extremities are connected to one pod, and at lower extremities – to another one.
ES Detector
The electrosurgical equipment is often induces artifacts on neurophysiological signals. With the detector the system always knows if the electrosurgical equipment is on. It helps to avoid the false alarms.
Auditory-visual Stimulator Unit
External unit with USB interface allows to add auditory and visual evoked potentials to the list of monitored modalities. Special LED silicon goggles and insert earphones are used as stimulators.
IOM Modalities
Main: free-run EMG, SSEP, MEP, DNS, pedicle screw test, EEG, AEP, VEP, train-of-four (TOF) stimulation.
Optional: anesthesia depth
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