LAUSR

The use of external ventricular drainage (EVD) has been one of the commonest procedures in everyday neurosurgery and a valuable tool for neurosurgeons and neurointensivists [6]. It is more frequently applied in the emergency setting either as a life-saving operation or for monitoring and controlling intracranial pressure (ICP). Although in most occasions, it is used temporarily, the eventual need for permanent diversion and controlled drainage of the cerebrospinal fluid (CSF) can also be required [3]. The traditionally tunneled technique has been initially described around 40 years ago and it is still the most commonly used worldwide [5]. After a skin incision and a burr hole usually in the non-dominant hemisphere, the catheter is inserted with freehand technique to the frontal horn. The catheter is then tunneled under the skin and externalized at a point where it is fixed with sutures. Next, the catheter is connected to a large volume bag and typically, to an ICP-monitoring system [6]. As expected, placement is not complication free as numerous problems can be encountered. Catheter misplacement, CSF leakage, wound and CSF infection, catheter migration and disconnection, intracranial bleeding, and neurological deficits have been repeatedly reported among others [4]. Further, not infrequently, reoperation cannot be avoided which can result in prolonged length of stay, increased costs, and morbidity. For about a decade, bolt-connected EVDs have been used in clinical practice in Denmark with success [2, 6]. The technique is quite different to the conventional tunneled. The catheter is initially cut to a length of 55–65 mm, is then attached to the distal metal tip of the bolt, and secured with a nonabsorbable suture. A stylet is inserted in the system which is followed by puncture of the ventricular system. The bolt is screwed into the burr hole and secured until it reaches an optimal fit. Lastly, the proximal end is shaped for a secure drain-fit with a Luer-Lock [2]. Bergdal et al. in 2013 tested the bolt-connected EVD in 97 patients. This study sample was compared with 57 patients who received a tunneled EVD. In the bolt-connected group, placement was statistically more accurate compared to the tunneled group. Patients subjected to the bolt-connected EVD had less reoperations compared to the tunneled group (2.1% vs. 14%) [2]. In 2016, Jensen et al. compared the two techniques in a larger number of patients, 141 and 131, for the bolt-connected and the tunneled group, respectively. It was found that bolt-connected EVDs had significantly less CSF leakage and significantly less complications requiring reoperation for EVD (e.g., mechanical problems) compared to tunneled EVDs. However, no difference in the infection rate was found between the two groups [6]. Assad and Bjarkam recently compared the two aforementioned techniques in a smaller patient sample (n = 49). This time, the study material was collected prospectively. Again, significantly more complications were seen in the tunneled group (including also infections) where it was found a 3.4 times higher risk for complications compared to the boltconnected group. None patient required revision in the boltconnected group, whereas, 17.4% of cases, the EVD was revised in the tunneled group. According to the authors, bolttunneled EVD should be the first choice, with the traditional tunneled method retaining its role in pediatric patients as well as in occipital insertion and through craniotomies [1]. Although the results are again in favor of the boltconnected EVD, the latter study has problems that raise skepticism and its findings should be interpreted with caution. The level of surgeon’s experience is unclear. Different surgeons with other levels of experience were likely interfered. Few patients received the bolt-connected EVD (n = 12) which cannot allow clear conclusions, similarly, when someone is trying This article is part of the Topical Collection on CSF Circulation