gms | German Medical Science

Objective: Patients with eloquently located cerebral lesions require surgery using intraoperative motor or speech mapping with monopolar or bipolar stimulation.50-60Hz stimulation with an Ojeman stimulator can mainly be performed by the surgeon independently, whereas monopolar stimulation requires additional trained personnel for handling of the intraoperative monitoring (IONM) system.Here,we report our experiences using a device that can be operated by the surgeon independently for both intraoperative techniques.

Methods: For monopolar and bipolar cortical/subcortical stimulation two preset programmes were available and intraoperatively used.One enabling EMG real-time tracking of 8 muscles for monopolar mapping and a second programme for 60 Hz stimulation. Motor mapping was performed using a standard monopolar probe connected to the device. EMG signals were screened in real-time on the device monitor. For 60 Hz stimulation a standard bipolar stimulation probe was connected through a second port. Preoperative application of subdermal EMG needles as well as intraoperative handling of the device were performed by the surgeons independently. Postoperatively, evaluation of autonomous handling and feasibility of the device for chosen test parameters was conducted.

Results: From 04/19-10/20, 106 patients with eloquently located cerebral lesions underwent surgery using the device.In 95% monopolar and in 45% of the cases bipolar mapping was performed. Regarding setup and sufficiency for cortical/subcortical mapping the device was evaluated as independently usable for motor and language mapping in 96 patients (90%). Complete resection was achieved in 67%, functional limit throughout resection was reached in 27% of the patients. 6 patients postoperatively suffered from a new neurological deficit. Follow-Up showed persistent deficit in 2 patients at 3-6 month follow-up (2%).

Conclusion: The device was evaluated as sufficient in 90 % concerning monopolar and bipolar mapping, set-up and handling was sufficient in all patients. However, missing SSEP monitoring was seen as a limitation in some cases and led to exclusion of patients with expected neurovascular conflicts. Concerning grade of resection and neurological outcome results were comparable to IONM procedures using standard devices. In our cohort surgeons were able to perform motor and speech mapping adequately and safely by independent use of the device.