Hydrated nucleus pulposus extrusion

In the healthy intervertebral disc (IVD) the main cell type of the nucleus pulposus (NP) is the notochordal cell embedded in a matrix composed of a complex network of negati interwoven in a mesh of mainly collagen type II fibres (1). The GAGs aggregate with hyaluronic acid and these negatively charged complexes create a strong osmotic gradien result over 80% of the heathy NP is composed of water creating a high intradiscal pressure. The high water content of the heathy NP is also responsible for the hyperintense on T2-weighted (T2W) magnetic resonance imaging (MRI) of the non-degenerated canine spine. The lamellae of the annulus fibrosus (AF) are composed of collagen fibrils m water than the NP thereby creating a hypointense AF signal surrounding the hyperintense NP signal on T2W MR images. Degeneration of the IVD is a complex multifactorial the composition of the cells and extracellular matrix of the NP, AF and endplate (1). Ultimately, intervertebral disc degeneration leads to loss of water content of the NP which on T2W MR images (‘black disc’).

Intervertebral disc disease and disc herniation is the most common spine disorder in dogs. Typically, but not exclusively, type 1 disc herniations (NP extrusion) are seen in cho herniations (AF and NP protrusion) are seen in non-chondrodystrophic dogs. The classical presentation of type1 intervertebral disc extrusion on T2W MR images is that of a d intense) nucleus pulposus extrusion. In this abstract, the clinical data, imaging data, and treatment results of dogs with an atypical presentation of a cervical hydrated NP extr presented.

Canine hydrated nucleus pulposus extrusion (HNPE) has been recently described as a cause of cervical compressive myelopathy with acute onset in non-chondrodystrophic one study HNPE was also documented in the thoracolumbar region (4). Previously, lesions affecting the dog’s cervical spine with similar clinical and MRI findings were named revisited due to histological evidence of NP material in the so-called cysts. [...]