Accuracy of the freehand pass technique for ventriculostomy catheter placement: retrospective assessment using computed tomography scans.

Objectives: The standard method of ventriculostomy catheter placement is a freehand pass technique using surface anatomical landmarks. This study was undertaken to determine the accuracy of successful ventriculostomy procedures performed at a single institution's intensive care unit (ICU). The authors hypothesized that use of surface anatomical landmarks alone with successful results frequently do not correlate with desirable catheter tip placement.

Methods: Retrospective evaluation was performed on the head computed tomography (CT) scans of 97 patients who underwent 98 freehand pass ventriculostomy catheter placements in an ICU setting. Using the postprocedure CT scans of the patients, 3D measurements were made to calculate the accuracy of ventriculostomy catheter placement.

Results: The mean distance (+/- standard deviation [SD]) from the catheter tip to the Monro foramen was 16 +/- 9.6 mm. The mean distance (+/- SD) from the catheter tip to the center of the bur hole was 87.4 +/- 14.0 mm. Regarding accurate catheter tip placement, 56.1% of the catheter tips were in the ipsilateral lateral ventricle, 7.1% were in the contralateral lateral ventricle, 8.2% were in the third ventricle, 6.1% were within the interhemispheric fissure, and 22.4% were within extraventricular spaces.

Conclusions: The accuracy of freehand ventriculostomy catheterization at the authors' institution typically required 2 passes per successful placement, and, when successful, was 1.6 cm from the Monro foramen. More importantly, 22.4% of these catheter tips were in nonventricular spaces. Although many neurosurgeons believe that the current practice of ventriculostomy is good enough, the results of this study show that there is certainly much room for improvement.