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Technique Tuesday - Lumbosacral Spinal Fluid Collection

Calling all equine veterinary students and professionals looking to level up their CPD skills! This Technique Tuesday, our co-founder and equine veterinary surgeon, Jennifer Corley, is sharing her expertise on the Lumbosacral Spinal Fluid Collection technique. This technique is an absolute gem for your arsenal, helping you excel in your field.  Have questions or comments? Drop them in the comment form below, and Jennifer will be more than happy to help! Stay tuned for more exciting insights and techniques from our amazing team! 



Equipment Required:

•    Sedation
•    Clippers 
•    Stocks (optional)
•    Chlorhexidine scrub solution and alcohol swabs
•    18G spinal needle 8 inches (20cm) long
•    No 15 scalpel blade
•    Mepivacaine 2% 2-3ml syringe with a 23-25G needle
•    Surgical gloves
•    5 x 5ml syringes
•    Sample pot


The horse needs to stand still and square. Stocks can be useful to protect from reflex kicks. Horses may react violently when the spinal membrane is puncture, good sedation and caution is required. 

Anatomy for site for collection:

Midline at a point intersected by a line drawn between the cranial border of the tuber sacrale. The site should be clipped and scrubbed then infiltrated with local anaesthetic. A small skin incision should be made to prevent dulling of the spinal needle. The needle should be advanced straight down exactly perpendicular to the horses back. The lumbosacral space is 5-6 inches down in an average horse. Increased resistance followed by a “pop” is usually a good indication that the membranes have been penetrated. Remove the stylet and CSF may be gently aspirated. If no fluid can be obtained and the needle is definitely properly placed try advancing very slowly 1mm at a time or turning the needle through 90 degrees and repeating aspiration. Raising the horses head and occluding the jugular veins for a few minutes can promote CSF movement caudally. If blood is seen multiple syringes should be drawn if the samples gradually clear this is likely to be from iatrogenic damage. If it remains uniform then this could be truly representative. 

Normal values for cerebrospinal fluid from lumbosacral space:

Total protein (g/L) 1-12
Total protein (mg/dl) 10-120
Nucleated cell count (/l) 0-7
Red blood cell count (/l) 0-600
Glucose (mmol/L) 2.2-4.2 
Glucose (mg/dL) 40-75
Creatine Kinase (IU) 0-8


1.    Martin Furr Lumbosacral spinal fluid collection. The Equine Hospital Manual. Page 79/80 Blackwell Publishing 2008. 
2.    Mayhew I Collection of CSF from the horse. Cornell Vet 65:500-502, 1975.