Background: The VP shunt operation is one of the most common in neurosurgical practice for treatment of hydrocephalus. However, malfunction due to proximal obstruction of the ventricular catheter caused by improper placement of the ventricular catheter tip is still a common occurrence. This retrospective study aimed to provide information on proper placement for problem evaluation and further planning in order to improve surgical outcomes in Rajavithi Hospital.
Objective: The present research in Rajavithi Hospital, Bangkok, examined the outcomes of ventricular catheter tip position in patients undergoing VP shunt operations using the parietal approach and parameters related to improper placement.
Material and Method: This was a retrospective study of 42 adult patients who underwent VP shunt operations via the parietal route. Only post-operative images (CT or MRI) obtained from Rajavithi Hospital’s PACS between November 2012 and
September 2014 were included. Baseline characteristics (sex, age, etiologies of hydrocephalus) and associated parameters
(burr hole location, ventricular size, angle of catheter to midline, length of catheter) were recorded and analyzed. From postoperative images, the positions of ventricular catheter tips were evaluated and graded on a 3-point scale as: 1) grade 1 -
optimal position, free-floating in cerebrospinal fluid in frontal horn; 2) grade 2 - touching choroid plexus or ventricular wall;
and 3) grade 3 - tip within or passing through brain parenchyma.
Results: From 42 parietal approach operations, grade 1 placement was found in 15 cases (35.7%), grade 2 in 11 (26.2%) and grade 3 in 16 cases (38.1%). Length of ventricular catheter and ventricular size were significant parameters in this study (p<0.001). The average length of catheter in grade 3 placements was significantly greater (139.04 mm) and ventricular size was significantly larger (22.59 mm) than in the other two grades.
Conclusion: Overlong ventricular catheter and large ventricular size were significant variables in poor placement outcomes in the present study. Pre-operative planning from CT or MRI can be used to determine the optimal length in order to improve
the outcomes.

Keywords: Hydrocephalus, Ventriculo-peritoneal shunt, Malfunction, Parietal approach