Neurosurgery

Neuromonitoring in neurosurgery

Neuromonitoring has become an integral part of many neurosurgical procedures, reflecting the ongoing efforts to improve patient safety, surgical precision, and overall treatment outcomes in the field of neurosurgery.

The Situation

During neurosurgical procedures, intraoperative neuromonitoring of the cranial nerves and central nervous system is standard practice.

If a tumour obscures vital brain areas, AVALANCHE® PLUS aids in locating tumour tissue with minimal damage while preserving brain function. Multimodal neuromonitoring also enables control of many cranial nerves.

AVALANCHE® PLUS

Multimodal Neuromonitoring

EMG – Assessing Motor Nerves
Monitoring motor cranial nerves (e.g., cranial nerves III-VII, IX-XII) via electromyography (EMG) is crucial for brain stem and skull base surgeries. Continuous EMG recording and playback help promptly detect motor structure approaches. Stimulated EMG measurements facilitate motor cranial nerve localisation and functional assessment.

SEP – Monitoring Sensory Pathways and Oxygenation Continuous somatosensory evoked potentials (SEP) recording offers vital insights into sensory pathway function. SEP monitoring ensures adequate brain oxygenation during brain aneurysm clipping and evaluates the spinal cord posterior funiculus during intramedullary tumours.

 
 

The AVALANCHE® PLUS SEP software features pre-set SEP channels. For instance, you can easily opt for SEP stimulation on the median nerve with just a click. There’s no need for manual switching of recording sites – AVALANCHE® PLUS automatically sets up the measuring channel, presents the required recording sites in an anatomical representation of the international 10-20 system, and assigns a stimulation channel. Simply drag and drop the displayed recording site onto a connection using the touch screen. Meanwhile, AVALANCHE® PLUS establishes an SEP frame in the main window, allowing you to monitor SEP signals throughout the surgery.

VEP – Monitoring the Optic Nerve

During surgery, the recording of visual evoked potentials (VEP) serves to monitor the functionality of the second cranial nerve (optic nerve), assessing the integrity of the visual pathway from the retina to the visual cortex. Dependable VEP recording aids in determining the extent of tumour resection required. Real-time adjustments in the surgical approach can mitigate permanent damage to the optic nerve caused by medical intervention. With AVALANCHE® PLUS VEP, the retina can be stimulated through the closed eye using LED flash goggles (red or white light). The adequacy of stimulation intensity, crucial for accurate VEP measurement, can be confirmed by simultaneously recording an electroretinogram (ERG).

MEP – Monitoring Central Motor Pathways

The measurement of motor evoked potentials (MEP), triggered by transcranial or direct cortical stimulation, assists in monitoring and safeguarding motor pathways in nearly all neurosurgical procedures. This involves identifying motor structures or cortical areas and functionally monitoring motor pathways such as pyramidal tracts or motor cranial nerves.

Configuration

If you’ve set up an AVALANCHE® PLUS EMG configuration, MEP setup becomes a breeze since the muscle selections are already made. Just create an MEP measurement frame by dragging and dropping the muscles – it’s that simple!

AEP – Monitoring Auditory Nerve and Brain Stem

The auditory nerve, a component of the vestibulocochlear nerve (cranial nerve VIII), resides primarily in the cerebellopontine angle. Surgical procedures near this area can cause significant stress on the auditory nerve. Preserving auditory function is crucial during surgeries involving the cerebellopontine angle, where predefined clicking stimuli are played to the patient through earphones.

The resulting action potentials are recorded cortically. Continuous monitoring of intraoperative changes in AEP potential helps identify surgical actions that may compromise auditory function. AEP potential monitoring offers surgeons real-time feedback on the functional status of the auditory pathway.

DCS - Direct Cortical Stimulation

with AVALANCHE® PLUS

Direct cortical stimulation is specifically crafted for pinpointing motor areas in the brain and the speech centre in neurosurgery or epilepsy surgery (cortical mapping). Brain tumours can alter the anatomy of the cortex, which naturally varies between patients. Without assistance, accessing tumour tissue with minimal damage to surrounding areas while preserving vital brain functions becomes challenging. With AVALANCHE® PLUS, visualising the patient’s individual cortex and pinpointing regions of interest becomes achievable. Special atraumatic stimulation probes are available for this purpose.

Whether using the Penfield or train technique, AVALANCHE® PLUS offers graphical representations of complex stimulation parameters for direct cortical stimulation. Any parameter adjustments are instantly clarified, ensuring full functionality paired with simple operation.

AVALANCHE® PLUS empowers you to become an expert!

SEP Phase Reversal

AVALANCHE® PLUS - Locating the central sulcus

Tumours affecting the central cortex can significantly change its anatomy, making it crucial to pinpoint structures around the central sulcus to determine the type and extent of tumour removal. SEP phase reversal measurements are utilised for identifying the central cerebral sulcus. Typically, signals generated by wrist stimulation (median nerve) are directly measured at the cortex using strip electrodes. A polarity shift in the evoked potential across the central sulcus is inferred from the SEP curves, indicating the “phase reversal” between the motor and sensory cortex. This approach helps preserve healthy tissue and minimises deficits.

With just a single click, select strip electrodes with 4, 6, or 8 contacts in SEP phase reversal and let AVALANCHE® PLUS handle the rest automatically: from electrode visualisation to phase reversal window and calculation – complex measurements configured instantly!

Subdural Strip Electrodes (with 4, 6 or 8 contacts)

Locating the Central Sulcus with AVALANCHE® PLUS

Discovering the central sulcus is made possible with AVALANCHE® PLUS through phase reversal SEP measurements. These measurements help identify the central sulcus by detecting the potentials evoked from wrist stimulation (median nerve), which are directly measured at the cortex using strip electrodes.

Featuring contact spacing of 10 mm and a cable length of 1.85 m, these electrodes come with connectors compliant with DIN 42802-1 standards. Each electrode is single sterile packed, disposable, and available in packs of one piece.

Electrode Tube

Streamlined intubation and lead placement in one step


Our cutting-edge technology saves precious time by eliminating the need for individual electrode application.

Featuring extended conductive contact surfaces, our electrode tube offers exceptional position tolerance while remaining flexible throughout. Positioning an electrode on the vocal cords has never been simpler.

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