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Intervertebral Disc Disease

Herniation of degenerate nucleus pulposus can result in sudden onset of clinical signs ranging from spinal pain to the loss of motor function and pain sensation. This is most common in the thoracolumbar spinal column but can affect the cervical spinal cord as well. Whilst most reports in the veterinary literature relate to dogs, intervertebral disc extrusions are also reported in cats

Herniation of the nucleus pulposus through the annulus of the disc and extrusion of nuclear material into the spinal canal, resulting in concussion of the spinal cord and concurrent compression. Genetic investigations have identified an FGF4 retrogene insertion on chromosome 12 associated with the development of Hansen Type I intervertebral disc extrusions and chondrodystrophy across several dog breeds.

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Image by Olga Guryanova


Clinical Characteristics & Diagnosis

Image by Joyce Hankins

ACVIM Consensus Statement on Acute Canine TL Intervertebral Disc Extrusion

Although there is much literature available on IVDE, the majority of it is observational. Consensus statements are important to review available literature, weigh the evidence and generate recommendations for management as well as highlight some areas of opportunity for further exploration (see image above). If you want to know more about the state of knowledge on IVDE and potential areas of research, have a read at this paper published in JVIM

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Comparison of Surgical Outcomes Associated With Compression Secondary to Hemorrhage and Intervertebral Disk Extrusions in Dogs

The goals of this retrospective case-control cross-sectional study were to (1) compare the success rate of routine surgical decompression in dogs with disc extrusion with epidural hemorrhage (DEEH) compression compared to Modified Frankel Score (MFS) matched dogs with non-hemorrhagic disk extrusions; (2) evaluate the extent of spinal cord compression on MRI compared to final patient outcomes in DEEH compression and (3) determine the surgical compression to decompression ratio and its relation to patient outcomes in cases of DEEH compression. A total of 143 dogs were included in this study.

The study supports the finding that when a similar level of surgical decompression is achieved, dogs with DEEH compression have similar outcomes to dogs with non-hemorrhagic IVDE for similar degrees of neurological dysfunction. Overall, the presenting Modified Frankel Score, rather than the extent of extradural compression visualised on MRI or presence of hemorrhage predicts functional outcome.

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Lumbar vertebral canal stenosis due to marked bone overgrowth after routine hemilaminectomy in a dog

Fascinating case report published in Acta Veterinaria Scandinavica of bone overgrowth after decompressive surgery for lumbar epidural hemorrhage resulting a year later in recurrence of neurological signs. Revision decompressive spinal surgery was performed with histopathology revealing normal or reactive osseous tissue. Nine-month postoperative, imaging studies showed a similar vertebral overgrowth, resulting in minimal spinal cord compression.

Colourful Pile of Old Books

Prognostic Factors in Canine Acute Intervertebral Disc Disease

This review article addresses what is known about predicting the prognosis in dogs with acute intervertebral disc disease.


Important prognostic considerations are recovery of ambulation, return of urinary and fecal continence, resolution of pain and, on the negative side, development of progressive myelomalacia. Initial injury severity affects prognosis as does type of IVDE, particularly when considering recovery of continence. Overall, loss of deep pain perception signals a worse outcome. When considering Hansen type 1 IVDE, the prognosis is altered by the choice of surgical vs. medical therapy. Cross-sectional area and length of T2 hyperintensity and loss of HASTE signal on MRI have also been associated with outcome.


Same-day surgery may reduce the risk of losing pain perception in dogs with thoracolumbar disc extrusion


The objective of this study was to compare the proportions of dogs with thoracolumbar disc extrusion that lose pelvic limb pain perception if surgery is performed on the day of admission or delayed overnight.

273 dogs were subdivided into two groups: early surgery (spinal decompression between their examination at day of admission and the following morning), and delayed surgery (did not undergo surgery between admission and the following morning). The proportion of dogs that lost pelvic limb pain perception overnight was compared between the early and delayed surgery groups.

Seven of 151 dogs in the early surgery group lost pain perception overnight compared to 15 of 122 in the delayed surgery group (P= 0.025).

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Residual volume of extruded disc material and residual spinal cord compression measured on postoperative MRI do not predict neurological outcomes in dogs following decompressive surgery for thoracolumbar intervertebral disc extrusion


The aim of this retrospective analytical study was to describe the volume of postoperative residual extradural material (VREM) and the ratio of the cross-sectional area (CSA) of maximum SC compression to the CSA of SC in a compression-free intervertebral space as MRI measures of preoperative and postoperative compression (residual spinal cord compression, RSCC), and to compare these measures between the neurological outcome in a group of dogs.

The prevalence of residual extradural material in postoperative MRI studies was 100%. No significant differences in mean preoperative SC compression, mean RSCC, mean SC decompression, or VREM were found between positive and negative outcome groups. 

Image by Joyce Hankins

A case series of 37 surgically managed, paraplegic, deep pain negative French bulldogs, with thoracolumbar intervertebral disc extrusion, from two English referral centres

There is a general perception that French bulldogs with severe thoracolumbar disc extrusions (TL-IVEDE) have a poor rate of recovery especially when compared to Dachshunds and other chondrodystrophic breeds. This recent paper evaluates the rate of recovery of nociception-negative French bulldogs with TL-IVDE.

Thirty-seven French bulldogs with absent nociception were evaluated and 14 of 37 (38%) regained deep pain perception by the time of discharge; only 19% with L4-S3 lesions regained deep pain perception compared to 11 of 21 (52%) of dogs with T3-L3 lesions!

The video above is one of the lucky Frenchies which can be seen to have regained motor function shortly after surgery.

Image by Ian Talmacs

Ultrasound-guided paravertebral perineural glucocorticoid injection for signs of refractory cervical pain associated with foraminal intervertebral disk protrusion in four dogs

Lateralised / foraminal disc disease in 4 dogs with chronic cervical pain refractory to standard conservative treatment was evaluated.

Ultrasound-guided paravertebral perineural injections with methylprednisolone acetate (1 mg/kg [0.45 mg/lb]) at the C3 nerve root in dog 1 and at the C7 nerve root in the other 3 dogs were performed. Injections were repeated at intervals of 4 weeks to 3 months on the basis of clinical response. None of the dogs had any complications from the procedures. For dogs 1 and 4, there was complete resolution of lameness and signs of cervical pain following perineural injections, and for dog 3, there was complete resolution of lameness and only minimal residual cervical pain. Dog 2 did not have long-lasting improvement.

Therapy & Prognosis

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