gms | German Medical Science

Objective: Bolt kit systems are increasingly used as an alternative to conventional external drainage systems. However, as in conventional implanted EVD catheters, contact between the ventricular system and skin surface and cerebrospinal fluid infection (CSF) is possible. Since 2009 we regularly utilize bolt-kit external ventricular drainage systems with silver bearing catheters inserted manually with a hand drill and skull screws for emergency ventriculostomy. For non-emergency situations, we use the conventional ventriculostomy with the subcutaneous tunnel technique which is performed in the operating room with a pneumatic drill. The aim of this analysis was to compare both techniques in terms of infection rates.

Method: 304 patient charts were retrospectively reviewed. Of these, 152 (aged 17–85 years, mean=55.4 years, female=45.4%) were enrolled in the final analysis. 152 were excluded due to use of non-silver bearing conventional catheters (N=111), bilateral implanted external ventricular drain (N=21), implantation time less than 24 hours (N=12), known or suspected cerebrospinal fluid infection at implantation (N=7) and catheter insertion within the previous 30 days (N=1). The control group with conventionally implanted silver-bearing catheters comprised 57 patients. The study group with bolt-kit silver bearing catheters comprised 95 patients. For assessing the primary outcome we recorded all CSF samples and resulting routine CSF cell counts. After removal of catheter tips we also reviewed microbiology reports for colonization.

Results: The occurrence of either positive CSF culture, colonization of the catheter tips or pleocytosis (white blood cell count > 4/ µl) in CSF fluid was not significantly different between the group with bolt-kit catheters and. catheters with conventional insertion (58.9% compared with 63.2%, p=0.61, chi-square-test). Positive CSF cultures occurred in 2 patients in the Bolt Kit group and 3 patients in the group with conventionally implanted silver-bearing catheters (2.1% compared with 5.3%, p=0.30, chi-square-test). Colonization of catheter tips occurred more often in Bolt-Kit catheters (7.4% compared with 1.8%, p=0.13, chi-square-test).

Conclusions: This analysis indicates that external ventricular drainage catheters implanted with a Bolt-Kit system outside the operating room do not significantly elevate the risk of CSF infection as compared to conventional implant methods.