Lumbosacral Foraminal Injections in Dogs: Preliminary Assessment of an Ultrasound- and Fluoroscopy-Guided Technique in a Cadaveric Model

Lumbosacral radiculopathy is a frequent cause of lumbosacral pain in both dogs and humans. Targeted lumbosacral foraminal perineural injections (commonly referred to as transforaminal epidural injections) are described in dogs and are widely used in medicine to treat lumbosacral radicular pain. This cadaveric study evaluated the injectate distribution achieved by lumbosacral foraminal injections using a combined ultrasound- and fluoroscopy-guided technique to position the tip of the needle at the cranial aspect of the foramen. Ten injections were performed in five dog cadavers using a contrast-dye mixture, and distribution was assessed by fluoroscopy, CT imaging, and anatomical dissections. Perineural epidural staining of L7 at the foraminal region was achieved in 90% of injections, with transforaminal epidural spread medial to the intervertebral foramen in 80% of injections. Subarachnoid spread occurred in 50-60%, while vascular uptake was uncommon (10-20%). The technique enabled consistent needle placement, even when nerve visualisation was limited. These findings indicate that the method can reliably achieve perineural epidural staining of L7 while minimising vascular uptake, supporting its potential clinical utility for targeted drug delivery in dogs with lumbosacral radiculopathy. Further research is needed to validate safety and efficacy in live patients.