Comparison of Ventricular and Lumbar Cerebrospinal Fluid Composition.

Objective Cerebrospinal fluid (CSF) analysis is a common diagnostic tool used to evaluate diseases of the central nervous system (CNS). We sought to determine whether there is a difference between the composition of CSF sampled from an external ventricular drain (EVD) and lumbar drain (LD) and whether this made a difference in guiding therapeutic decisions. Patients and Methods This study was a retrospective analysis from a single neurosurgery service between the dates of January 2011 and April 2019. A total of 12,134 patients were screened. Inclusion criteria were ages 18-80 and the presence of both an EVD and LD. Exclusion criteria were not having both routes of CSF sampling and the inability to determine which samples originated from which compartment. Results Six patients underwent simultaneous spinal and ventricular routine CSF sampling <24 hours apart and were analyzed for their compositions. There were 42 samples, but only 20 paired EVD-LD samples that could be analyzed. When comparing the EVD and LD sample compositions, there were statistically significant differences in white blood cells (WBCs; p = 0.040), total protein (p = 0.042), and glucose (p = 0.043). Red blood cells (RBCs; p = 0.104) and polymorphonuclear leukocytes (PMN; p = 0.544) were not statistically significant. We found a statistically significant correlation between cranial and spinal CSF WBC (r = 0.944, p < 0.001), protein (r = 0.679, p = 0.001), and glucose (r = 0.805, p < 0.001). We also found that there was a significant correlation between CSF and serum glucose (r = 0.502, p = 0.040). There was no statistically significant correlation between RBCs (r = 0.276, p = 0.252). Conclusion Our results demonstrate a correlation between the cranial and spinal CSF samples, except for RBCs, with statistically significant differences in WBC, glucose, and protein values between the two sites. This confirms that sampling CSF via lumbar puncture, which carries less risk than a ventriculostomy and provides accurate data to help establish a diagnosis for intracranial pathologies.