The Aalborg Bolt-Connected Drain (ABCD) study: a prospective comparison of tunnelled and bolt-connected external ventricular drains

BACKGROUND: Acutely increased intracranial pressure (ICP) is frequently managed by external ventricular drainage (EVD). This procedure is life-saving but marred by a high incidence of complications. It has recently been indicated that bolt-connected external ventricular drainage (BC-EVD) compared to the standard technique of tunnelled EVD (T-EVD) may result in less complications.

AIM: To prospectively sample and compare two cohorts by consecutive allocation to either BC-EVD or T-EVD from the introduction of the BC-EVD technique in our department and 12 months onward.

METHODS: Patients undergoing ventriculostomy between the 1st of March 2017 and the 28th of February 2018 were considered for inclusion. The neurosurgeon on-call sovereignly set the indication and decided on EVD type (BC-EVD or T-EVD), consequently resulting in two cohorts as 3/7 senior neurosurgeons on call were open to the use of BC-EVD, while 4/7 were reluctant to use this technique. Data was continuously collected using patient records, including results of cerebrospinal fluid (CSF) culturing and available CT/MRI-scans. Recorded complications included CSF leakage, accidental discontinuation, placement-related intracranial haemorrhage, malfunction, migration, infection and revision.

RESULTS: Forty-nine EVDs (32 T-EVDs/17 BC-EVDs) were included; 19/32 (59.4%) T-EVDs and 3/17 (17.6%) BC-EVDs were found to have complications (p = 0.007). The relative risk of complications when using T-EVD was 3.4 times that of BC-EVD.

CONCLUSION: Ventriculostomy by BC-EVD compared to T-EVD reduces incidence and risk of complications and should be the first choice in EVD placement. That said, T-EVD has a role in paediatric patients and for intraoperatively and occipitally placed EVDs.