gms | German Medical Science

Objective: In patients with narrow ventricles catheterisation can proove difficult resulting in misplacement or frustrane trials with the potential consequence of unneccesary damage to brain tissue. Navigational systems are increasingly used in neurosurgery and could be beneficial in these cases. Recently, navigational techniques that do not require fixation of the anatomical structures and techniques for navigated control of flexible instruments have become available.

Methods: The application of a new modul for navigated ventricular catheterisation (AxiEM Ventricular Access) using flexible electromagnetic navigation and a dynamic reference frame is evaluated. A StealthStation AxiEM navigational system was used. CT-data was obtained using multi-slice CT. In four patients suffering from pseudotumor cerebri, meningeosis carcinomatosa and normal pressure hydrocephalus the technique was applied. Evaluation of the accuracy was performed by correlation of the planned target in intraoperative screenshots and postoperative CT.

Results: Navigated catheter placement was accurate and easy to perform in three instances. In one patient it was successful only in the second attempt, since the surgical plan was not followed correctly due to human error. Evaluation of intraoperative screenshots and postoperative CT showed corresponding positions of the catheter tip. The system was easy to handle, although electromagnetic interferences had to be taken into consideration. The time added to the surgical procedure was 30 minutes.

Conclusions: The presented method for navigated catheter placement is helpful in cases with narrow ventricles as it reduces the risk of misplacement or repeated catheterisation trials. The relevance of flexible navigation is subject to further discussion. The use of a dynamic reference frame is helpful, as it allows repositioning of the patient´s head during the procedure.