Ex Vivo Assessment of an Ultrasound-Guided Injection Technique of the Lumbosacral Disc in the Horse.

OBJECTIVES: The aim of this study was to describe an ultrasound-guided injection technique of the lumbosacral disc in horses through the cranial vertebral notch of the sacrum and to evaluate both accuracy and potential complications of the technique on equine cadavers. MATERIALS AND METHODS: Twenty-four injections of the lumbosacral area were performed on 12 equine cadavers shortly after euthanasia under ultrasound guidance with the horse in recumbency using two different dyes (one colour for each side). The lumbosacral area was dissected in each horse and the accuracy of the technique, as well as its potential complications, was evaluated detecting the dyes and the structures that have been coloured. RESULTS: The lumbosacral area was correctly reached in only 11/24 injections. However, this technique allowed a lumbosacral peridiscal injection in 7/12 horses. The main difficulty was reaching the ventral opening of the L6-S1 intervertebral foramen that is partially hidden by the iliac wing on ultrasound. Puncture of the vertebral canal has been observed in 11/24 cases. The L6 spinal nerve roots emerging through the intervertebral foramen could potentially be damaged when inserting the needle. CLINICAL SIGNIFICANCE: The described ultrasound-guided technique allows peridiscal injection in the lumbosacral space in less than 60% of cases with potential sciatic nerve damage. Further investigations are warranted before using this technique in clinical practice in horses suffering from lumbosacral lesions.

Assessment of a computed tomography guided injection technique of the lumbo-sacral disc in sheep.

OBJECTIVES: Recent data indicate that degeneration of intervertebral discs occurs naturally in sheep, with a higher prevalence at the level of the lumbo-sacral disc. The objective of this ex vivo study was to evaluate a computed tomography (CT) guided method of injection into the ovine lumbo-sacral disc. METHODS: Six euthanatized sheep were used for identification of the approach plane, the optimal direction of the needle and the mean distance from skin to disc. Dissection after injection of coloured ink was used to determine the anatomical structures that were penetrated. In seven other animals, all spines were assessed beforehand by CT and magnetic resonance imaging to determine whether disc pathology was present. The final position of the needle was assessed by CT to determine the accuracy of the technique. Contrast agent was injected to identify any problems associated with administration of liquid into the disc. RESULTS: The CT guided injection technique was easy to perform and enabled adequate positioning of the needle into all (n = 7) lumbo-sacral discs. Distance between the skin and the disc ranged between 12 and 17 cm. No organ, vascular or nervous structure was penetrated and the needle path remained intramuscular without penetration of the peritoneal cavity. Contrast medium leaked out through three degenerate discs. CLINICAL SIGNIFICANCE: The current study described a consistently safe and accurate CT guided injection technique to the lumbo-sacral disc for future in vivo experimental studies that will use sheep as animal model for human intervertebral disc disease disease.