The effect of prior thecal puncture on cerebrospinal fluid analytes in normal adult horses.

BACKGROUND Serial cerebrospinal fluid (CSF) analysis might be required in clinical neurologic disease. The effect of lumbosacral (LS) or cervical (C1-C2) centesis on subsequent CSF cytologic analyses has not been investigated in horses. OBJECTIVE To evaluate the effect of thecal puncture on subsequent CSF analyses ANIMALS: Ten healthy adult horses. METHODS Prospective study. Horses were randomly assigned to undergo CSF collection twice, 14 days apart, from either the C1-C2 or LS space. After a 4-month washout period, CSF collection was repeated from the alternate site. Continuous data were analyzed using linear mixed-effects models and count data using mixed-effects negative binomial regression. Statistical significance was set at P < .05. RESULTS There was no significant effect of collection day (day 0 or day 14) for any CSF analytes, including protein concentration (C1-C2: 45 [95% CI: 33-57] mg/dL day 0 vs 49 [95% CI: 39-62] mg/dL day 14, P = .12; LS: 64 [95% CI: 41-100] mg/dL day 0 vs 83 [95% CI: 53-129] mg/dL day 14, P = .37), or nucleated cell count (C1-C2: 2 [95% CI: 1-4] cells/μL day 0 vs 3 [95% CI: 1-4] cells/μL day 14, P = .65; LS: 3 [95% CI: 2-5] cells/μL day 0 vs 5 [95% CI: 3-8] cells/μL day 14, P = .10). There was no significant difference in EPM titer or EPM serum : CSF ratio between days 0 and 14. CONCLUSIONS AND CLINICAL IMPORTANCE Repeat thecal puncture from the LS or C1-C2 space 2 weeks apart does not appear to impact CSF analytes.