The 9th annual British Veterinary Neurology Society (BVNS) Symposium took place on March 20th, 2024 in Manchester, focusing on the theme of “Disc Disease – You Think You Know It…”. This meeting brought together veterinary neurologists, neurosurgeons, geneticists and other experts to share the latest research on intervertebral disc disease (IVDD), which disproportionately affects breeds like dachshunds.
The programme featured several presentations highly relevant for dachshund owners and breeders concerned about this painful and debilitating condition. Here were some of the key highlights:
Keynote presentation
The symposium included a keynote presentation by Dr. Nisaharan Srikandarajah, a consultant neurosurgeon from The Walton Centre in Liverpool, titled “Time is Spine.” Dr. Srikandarajah discussed the concept of early surgical intervention for conditions like cauda equina syndrome and spinal cord injury in human patients.
Cauda equina syndrome occurs when the bundle of nerve roots below the termination of the spinal cord (the cauda equina) becomes compressed, causing symptoms like low back pain, bladder/bowel dysfunction, and sensory/motor deficits in the legs. It requires urgent decompressive surgery to try to halt or reverse neurological deterioration.
Dr. Srikandarajah explored whether there is validity to the idea of “time is spine” – that quicker surgical decompression leads to better neurological outcomes – for cauda equina syndrome and other acute spinal cord injuries in humans. He reviewed the current literature and presented contemporary clinical practices regarding the optimal timing of surgery for maximal preservation of function.
While the effectiveness of very early (<24 hours) versus later surgical decompression remains an area of ongoing research and debate in human medicine, Dr. Srikandarajah’s talk provided relevant insight that may help guide decision-making around surgical timing for intervertebral disc herniations veterinary patients as well.
Genetics of Disc Degeneration
Dr. Frances Williams from King’s College London discussed the genetics behind intervertebral disc degeneration in humans based on studies like the UK BioBank and the TwinsUK adult twin registry. This work aims to identify genetic risk factors that may also apply to disc degeneration in dogs. Understanding the genetic underpinnings is an important step towards developing treatments that could slow or halt disc degeneration. Frances Williams delved into the genetic aspects of intervertebral disc disease (IVDD) and chronic back pain, shedding light on the complex interplay between genetics, lifestyle, and environmental factors. Twin studies revealed a significant heritable component in lumbar disc degeneration, underscoring the need for further genetic research in understanding back pain. At least 3 genes have been identified with causal associations with back pain. This opens doors for the development of potential genetic tests to identify the genetic basis of IVDD in dogs predisposed to the condition.
Minimally Invasive Spinal Surgery
Dr. Julien Guevar discussed the potential of minimally invasive spine surgery (MISS) techniques for intervertebral disc disease in dogs. To reduce tissue disruption and potentially accelerate recovery, researchers are exploring new surgical techniques that utilise smaller incisions. These minimally invasive procedures may offer promising alternatives to traditional open surgery. While challenging due to the small operating field, MISS approaches like miniopen hemilaminectomies may reduce surgical trauma and post-operative pain compared to conventional open surgery. Further research is still needed in this area.
Spinal Rehabilitation
Dr. Marianne Dorn (The Rehab Vet) provided an overview of key principles and exercises for neurorehabilitation of dogs suffering from intervertebral disc extrusions. This covered strategies to help patients relearn natural movement patterns, setting achievable goals, avoiding fatigue, ensuring comfort and keeping them motivated during recovery. Here are some key rehabilitation practices that Marianne discussed:
- Promoting Natural Movement: Encouraging patients to move in ways that mimic their natural postures and gait patterns is crucial for regaining optimal function.
- Curbing Compensatory Movements: Compensatory movements, such as scooting or dragging the limbs, can hinder proper gait re-learning. Rehabilitation helps patients avoid these patterns and focus on correct movement.
- Setting Realistic Goals: Setting achievable milestones throughout the rehabilitation journey keeps patients motivated and fosters a sense of accomplishment.
- Positive Reinforcement is Key: Utilising positive reinforcement techniques, like food rewards, during exercise sessions can significantly enhance motivation and engagement.
Is surgery for disc extrusions overrated?
Professor Paul Freeman discussed his team’s research at Cambridge Vet School and said there are good reasons to question the current consensus approach to IVDE. He explained that there is a finite amount of money to pay for IVDD operations and, with a high recurrence rate, many owners can’t afford a 2nd surgery. His team had studied recovery rates in dogs treated conservatively. 49 out of 51 dogs that were Deep Pain Positive (Grade 3-4) recovered and their time to ambulation averaged 10 days. 10 of 21 Deep Pain Negative (Grade 5) dogs recovered in a median time of 3 weeks.
Failure to recover was unrelated to the degree of spinal cord compression. Paul asked several questions that were probably quite challenging for the audience of neurosurgeons:
Why do we still consider this as a surgical disease?
How do we pick the ones that really need surgery?
Should we allow 2-3 weeks to wait and see?
Are we making some dogs worse by doing surgery?
Overall, his team’s findings showed that outcomes on recovery with conservative management were no different from surgically treated cases.
Mineral Changes in Degenerated Discs
Researchers from the University of Cambridge IVDD Research Group presented fascinating findings on the mineral composition of degenerated and extruded disc material from chondrodystrophic dogs like dachshunds. Their analysis suggests there is a transformation from amorphous calcium phosphate to crystalline hydroxyapatite as discs degenerate, which may predispose them to extrusion. Identifying these mineral phase changes could shed light on the pathological processes driving disc extrusion.
In conclusion
While much remains unknown about what triggers disc extrusion and paralysis in high-risk breeds, this symposium highlighted how active research from multiple angles is enhancing our understanding of the disease process. With continued investigations into genetics, biomineralisation, surgical techniques and rehabilitation, there is hope for improving prevention and treatment of IVDD in the future. Dachshund owners and breeders should stay tuned for the latest updates from the veterinary neurology field.