Jens Fichtner, Erdem Güresir, Volker Seifert and Andreas Raabe
Catheter-related infection of CSF is a potentially life-threatening complication of external ventricular drainage (EVD). When using EVD catheters, contact between the ventricular system and skin surface occurs and CSF infection is possible. The aim of this analysis was to compare the efficacy of silver-bearing EVD catheters for reducing the incidence of infection with standard nonimpregnated EVD catheters in neurosurgical patients with acute hydrocephalus.
Two hundred thirty-one consecutive patients were retrospectively reviewed. Of these, 164 were enrolled in the final analysis. Six patient charts were incomplete or missing, 15 patients were excluded because of catheter insertion within the previous 30 days, 6 because of a suspected CSF infection before ventriculostomy, 7 because the catheter was removed < 24 hours after insertion, and 33 patients because of the requirement of bilateral ventriculostomy. The control group with standard nonimpregnated EVD catheters consisted of 90 patients. The study group with silver-bearing EVDs consisted of 74 patients. For assessing the primary outcome, the authors recorded all CSF samples and liquor cell counts routinely obtained in sterile fashion. After removal of the catheters, they also reviewed microbiology reports of the removed catheters to assess colonization of the catheter tips.
The occurrence of a positive CSF culture, colonization of the catheter tip, or liquor pleocytosis (white blood cell count > 4/μl) was ~ 2 times less in the study group with silver-bearing EVD catheters than that in the control group (18.9% compared with 33.7%, p = 0.04). Positive CSF cultures alone occurred 2 times less frequently for microorganisms in the study group (2.7% compared with 4.7%, p = 0.55). Silver-bearing catheters were 4 times less likely to become colonized as nonimpregnated EVDs (1.4% compared with 5.8%, p = 0.14). Liquor pleocytosis was half as likely in the study group (17.6% compared with 30.2%, p = 0.06).
Although of limited sample size and thus underpowered for subgroup analysis, this analysis indicates that EVD catheters impregnated with silver nanoparticles and an insoluble silver salt may reduce the risk of catheter-related infections in neurosurgical patients.
Clemens Raabe, Jens Fichtner, Jürgen Beck, Jan Gralla and Andreas Raabe
Frontal ventriculostomy is one of the most frequent and standardized procedures in neurosurgery. However, many first and subsequent punctures miss the target, and suboptimal placement or misplacement of the catheter is common. The authors therefore reexamined the landmarks and rules to determine the entry point and trajectory with the best hit rate (HtR).
The authors randomly selected CT scans from their institution’s DICOM pool that had been obtained in 50 patients with normal ventricular and skull anatomy and without ventricular puncture. Using a 5 × 5–cm frontal grid with 25 entry points referenced to the bregma, the authors examined trajectories 1) perpendicular to the skull, 2) toward classic facial landmarks in the coronal and sagittal planes, and 3) toward an idealized target in the middle of the ipsilateral anterior horn (ILAH). Three-dimensional virtual reality ventriculostomies were simulated for these entry points; trajectories and the HtRs were recorded, resulting in an investigation of 8000 different virtual procedures.
The best HtR for the ILAH was 86% for an ideal trajectory, 84% for a landmark trajectory, and 83% for a 90° trajectory, but only at specific entry points. The highest HtRs were found for entry points 3 or 4 cm lateral to the midline, but only in combination with a trajectory toward the contralateral canthus; and 1 or 2 cm lateral to the midline, but only paired with a trajectory toward the nasion. The same “pairing” exists for entry points and trajectories in the sagittal plane. For perpendicular (90°) trajectories, the best entry points were at 3–5 cm lateral to the midline and 3 cm anterior to the bregma, or 4 cm lateral to the midline and 2 cm anterior to the bregma.
Only a few entry points offer a chance of a greater than 80% rate of hitting the ILAH, and then only in combination with a specific trajectory. This “pairing” between entry point and trajectory was found both for landmark targeting and for perpendicular trajectories, with very limited variability. Surprisingly, the ipsilateral medial canthus, a commonly reported landmark, had low HtRs, and should not be recommended as a trajectory target.
Michael Fiechter, Jens Fichtner, Sergej Feiler, Radu Olariu, Jürgen Beck, Andreas Raabe and Christian T. Ulrich
Jürgen Beck, Christian Fung, Christian T. Ulrich, Michael Fiechter, Jens Fichtner, Heinrich P. Mattle, Marie-Luise Mono, Niklaus Meier, Pasquale Mordasini, Werner J. Z’Graggen, Jan Gralla and Andreas Raabe
Spinal CSF leakage causes spontaneous intracranial hypotension (SIH). The aim of this study was to characterize CSF dynamics via lumbar infusion testing in patients with and without proven spinal CSF leakage in order to explore possible discriminators for the presence of an open CSF leak.
This analysis included all patients with suspected SIH who were treated at the authors’ institution between January 2012 and February 2015. The gold standard for “proven” CSF leakage is considered to be extrathecal contrast accumulation after intrathecal contrast injection. To characterize CSF dynamics, the authors performed computerized lumbar infusion testing to measure lumbar pressure at baseline (opening pressure) and at plateau, as well as pulse amplitude, CSF outflow resistance (RCSF), craniospinal elastance, and pressure-volume index.
Thirty-one patients underwent clinical imaging and lumbar infusion testing and were included in the final analysis. A comparison of the 14 patients with proven CSF leakage with the 17 patients without leakage showed a statistically significantly lower lumbar opening pressure (p < 0.001), plateau pressure (p < 0.001), and RCSF (p < 0.001) in the group with leakage. Sensitivity, specificity, and positive and negative predictive values for an RCSF cutoff of ≤ 5 mm Hg/(ml/min) were 0.86, 1.0, 1.0, and 0.89 (area under the curve of 0.96), respectively. The median pressure-volume index was higher (p = 0.003), and baseline (p = 0.017) and plateau (p < 0.001) pulse amplitudes were lower in patients with a proven leak.
Lumbar infusion testing captures a distinct pattern of CSF dynamics associated with spinal CSF leakage. RCSF assessed by computerized lumbar infusion testing has an excellent diagnostic accuracy and is more accurate than evaluating the lumbar opening pressure. The authors suggest inclusion of RCSF in the diagnostic criteria for SIH.
Jürgen Beck, Jan Gralla, Christian Fung, Christian T. Ulrich, Philippe Schucht, Jens Fichtner, Lukas Andereggen, Martin Gosau, Elke Hattingen, Klemens Gutbrod, Werner J. Z'Graggen, Michael Reinert, Jürg Hüsler, Christoph Ozdoba and Andreas Raabe
The etiology of chronic subdural hematoma (CSDH) in nongeriatric patients (≤ 60 years old) often remains unclear. The primary objective of this study was to identify spinal CSF leaks in young patients, after formulating the hypothesis that spinal CSF leaks are causally related to CSDH.
All consecutive patients 60 years of age or younger who underwent operations for CSDH between September 2009 and April 2011 at Bern University Hospital were included in this prospective cohort study. The patient workup included an extended search for a spinal CSF leak using a systematic algorithm: MRI of the spinal axis with or without intrathecal contrast application, myelography/fluoroscopy, and postmyelography CT. Spinal pathologies were classified according to direct proof of CSF outflow from the intrathecal to the extrathecal space, presence of extrathecal fluid accumulation, presence of spinal meningeal cysts, or no pathological findings. The primary outcome was proof of a CSF leak.
Twenty-seven patients, with a mean age of 49.6 ± 9.2 years, underwent operations for CSDH. Hematomas were unilateral in 20 patients and bilateral in 7 patients. In 7 (25.9%) of 27 patients, spinal CSF leakage was proven, in 9 patients (33.3%) spinal meningeal cysts in the cervicothoracic region were found, and 3 patients (11.1%) had spinal cysts in the sacral region. The remaining 8 patients (29.6%) showed no pathological findings.
The direct proof of spinal CSF leakage in 25.9% of patients suggests that spinal CSF leaks may be a frequent cause of nongeriatric CSDH.