Introduction: Few prospective studies have analyzed catheter position accuracy and procedure-related complications, although external ventricular drain (EVD) placement represents a common procedure. Our study was designed to prospectively collect these results.
Methods: Since November 2009, all patients requiring EVD placement underwent a postoperative CT scan to check EVD position and hemorrhage rates. EVD accuracy was graded based on catheter tip position and trajectory: an optimal placement in the foramen of Monro or ipsilateral frontal horn corresponded to grade 1, a suboptimal placement in other CSF spaces to grade 2, and misplacement with catheter tip or path passing respectively through non-eloquent or eloquent parenchyma to grades 3 or 4.
Results: Sixty-six EVDs were placed in 50 patients. Grades 1 to 4 were noted respectively in 58%, 9%, 18% and 15%. Out of 22 grades 3 and 4, 10 (45%) EVDs needed to be replaced while only one grade 1 EVD became non-functional after 3 days (p<0.001). Statistical significant risk of misplacement were Evans index lower than 0.2 (p=0.04) and intracranial catheter length longer than 6.5 cm (p<0.001), while surgeon’s experience and preoperative midline shift were not. Six postoperative hemorrhages were observed either along the EVD tract (n=5) or in the ventricles (n=1). All were of small size and none required drainage. Multiple attempts to insert EVD were a statistical significant hemorrhage risk factor (p<0.001) while coagulation disorders were not associated with a higher risk.
Conclusions: Similarly to the literature, our preliminary study suggests that free-hand EVD insertion has a low accuracy and potential complications. Too deep catheter insertion is the main procedure-related pitfall that could be easily avoided. Multiple attempts represent the main risk factor of hemorrhages.
Patient Care: By avoiding several pitfalls during free-hand EVD insertion, EVD complication rate could be decreased
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Better understand the importance of EVD complications
2) Identify ways to better avoid them in their current practice.
References: 1. Kakarla and al, Safety and accuracy of bedside external ventricular drain placement., Neurosurgery. 2008 Jul;63(1 Suppl 1):ONS162-6; discussion ONS166-7.
2. Park and al, Accuracy and Safety of Bedside External Ventricular Drain Placement at Two Different Cranial Sites : Kocher’s Point versus Forehead, J Korean Neurosurg Soc 50 : 317-321, 2011
3. Huyette and al, Accuracy of the freehand pass technique for ventriculostomy catheter placement: retrospective assessment using computed tomography scans.J Neurosurg. 2008 Jan;108(1):88-91.
4. Gardner and al, Hemorrhage rates after external ventricular drain placement. J Neurosurg. 2009 May;110(5):1021-5.