gms | German Medical Science

Objective: Intraoperative neurophysiological monitoring (IONM) is a well established technique in cerebral and spinal neurosurgery. In order to facilitate the presentation of the monitoring data for the surgeon, we developed a technique which allows a superimposed and transparent visualisation of the monitoring data in the eyepiece of the surgical microscope. Here, we report the results of a feasibility analysis.

Method: The technique has been applied by 4 neurosurgeons in 86 cerebral and spinal procedures (43 acoustic neuromas, 5 trigeminal neuralgias, 5 supratentorial meningiomas, 12 infratentorial meningiomas, 4 brainstem cavernomas, 4 tumors of 4. ventricle, 3 Chiari malformations, 2 vascular cases and 8 spinal tumors). During the operations: 1) System stability, 2) Equipment practicability and 3) Convenience of the system were evaluated by neurosurgeon and technician. System requirements are an ISIS IOM Neuromonitoring System with NeuroExplorer software (Inomed Medizintechnik GmbH, Emmendingen, Germany) integrated into an operation microscope series OPMI^® Pentero^® (Carl Zeiss Meditec AG, Jena, Germany).

Results: In all 86 neurosurgical procedures, no system specific failures have been detected. After a short learning curve, all neurosurgeons continuously applied the system. The IM-IONM integrated intuitively into the neurosurgical workflow, despite additional visual information is presented within the microscopical field. Both, technicians as well as neurosurgeons reported improved communication, facilitating differentiated cranial nerve stimulation and faster reaction on monitoring changes.

Conclusions: The IM-IONM technique allows the surgeon to continue focussing on the surgical field but simultaneously enables the surgeon to interpret alterations in neurophysiological signals and to react immediately in order to minimise the possibility of damage to neuronal structures.