Comparison of 2 collection methods for cerebrospinal fluid analysis from standing, sedate adult horses

Abstract

Background Cerebrospinal fluid (CSF) analysis is an important component of the evaluation of horses with neurologic disease. Lumbosacral (LS) centesis is routine, but CSF is also collected from the space between the first and second cervical vertebrae (C1‐C2). Objectives To compare collection times, CSF cytology results, and equine protozoal myelitis (EPM) titers of CSF collected from the C1‐C2 and LS sites. Animals Fifteen university‐owned adult horses with no evidence of neurologic disease, and 9 horses with signs of neurologic disease: 3 university‐owned and 6 client‐owned. Methods Prospective study. Cerebrospinal fluid collection from the LS space and C1‐C2 space of each horse was performed in randomized order. Continuous data were analyzed using mixed‐effects linear models and count data using mixed‐effects negative binomial regression. Statistical significance was set at P < .05. Results Cerebrospinal fluid collected from the C1‐C2 site had a significantly lower mean protein concentration (49 [95% CI: 43‐55.8] mg/dL C1‐C2 versus 52.1 [95% CI: 45.7‐59.3] mg/dL LS; P = .03) and red blood cell count (6 [95% CI: 2‐16] cells/μL versus 33 [95% CI: 13‐81] cells/μL; P = .02). Collection time, total nucleated cell count, EPM titers, and serum:CSF EPM titer ratios were not significantly different between collection sites. Conclusions and Clinical Importance Cerebrospinal fluid from the C1‐C2 space provides an acceptable alternative to LS CSF collection with decreased likelihood of clinically important blood contamination of samples.

Comparison of Fluid Analysis and Cytologic Findings of Cerebrospinal Fluid Between Three Collection Sites in Adult Equids With Neurological Disease

“…Despite these adverse outcomes, it is a widely utilized procedure that anecdotally has very low rates of complication. The standing cervical CSF collection technique at the AA space provides increased access and ease of CSF collection for equids with intra-cranial and cranial cervical spinal cord disease ( 8 ).…”

“…While LS centesis may still be preferred in patients with neurolocalization of signs caudal to T2, due to caudal flow of CSF, AA puncture likely still provides a diagnostic sample in patients where minimal blood contamination and patient reaction are prioritized ( 8 ). Lumbosacral puncture may be less desirable based on clinician preference due to the safety risk assumed by the clinician performing the procedure associated with the proximity to the hind legs, the need to be elevated to obtain a dorsal approach, and explosive reactions occasionally observed in the patients ( 7 , 8 ). These risks can be somewhat mitigated through appropriate sedation and restraint, such as the use of stocks, when available.…”

“…In severely ataxic patients, recovery from general anesthesia can be difficult; thus, standing techniques are often preferred. While the LS site is still a widely used location, the technique described by Pease et al in 2012 to access the AA space has become increasingly popular due to its technical ease, lack of reaction from patients, safety for the practitioner, and since it lacks the requirement for general anesthesia ( 8 , 9 ).…”

“…Recent literature has shown no difference in nucleated cell count in CSF from horses with no evidence of neurological disease when sampling the AA and the AO sites, but did show higher TP in samples from the AA site ( 14 ). While CSF collected from the AA and LS sites ( 8 ) and CSF from the AO and AA sites have previously been compared ( 14 ), there are no published comparisons between all three collection sites. Separate reference ranges for albumin have been proposed in human literature based on sample site, but specific reference ranges for CSF collected from the AA site in horses have not yet been established ( 10 ).…”

Highlights of recent clinically relevant papers

“…In this prospective study Hayley Chidlow and colleagues in the USA compared two collection methods for cerebrospinal fluid (CSF) analysis from standing sedated horses.…”