Accuracy of bolt external ventricular drain insertion by neurosurgeons of different experience

The accuracy of tunneled external ventricular drain (EVD) placement has been shown to be similar among practitioners of varying experience, but this has not yet been investigated for bolt EVDs. Tunneled and bolt EVDs are distinct techniques, and it is unclear if conclusions regarding accuracy can be inferred from one method to the other. The goal of this study was to determine whether neurosurgical experience influences the accuracy of bolt EVD placement.

We performed a single-center retrospective analysis of accuracy of bolt EVD placement between 1st December 2018 and 31st May 2020, comparing the accuracy outcomes between three levels of training (junior trainees (JT); mid-grade trainees (MT); senior trainees/fellows (ST)). Accuracy was determined radiologically by two methods: Kakarla grade and by measuring the distance of the catheter tip to its optimal position (DTOP) at the foramen of Monro.

Eighty-seven patients underwent insertion of bolt EVDs, of which n = 19 by JT, n = 40 by MT and n = 28 by ST, with a significant difference found between training grades in the median Kakarla grade (p = 0.0055) and in the accuracy of placement as per DTOP (p = 0.0168).

In contrast to previous published results on tunneled EVDs, we demonstrate that the accuracy of bolt EVD placement is dependent on neurosurgical experience. Our results draw awareness to the fact that the bolt EVD technique can represent a challenge for less experienced practitioners and underline the importance of dedicated training to support the safe insertion of bolt ventricular catheters.