Eric

Eric was only 11 months old but had been suffering periodically with episodes of neck pain for around 3 months. This was bad enough to make him scream in pain. He’d been to his local vet to be checked over and had even had some X-rays taken, which showed nothing abnormal. Things came to a head in March 2022, when he started screaming in severe pain and was suddenly unable to walk. Although it was the weekend, this turn for the worse meant that Eric had to be treated as promptly as possible and he was sent all the way from his home in Wales to HSR to be examined by the specialist on call.

Eric was severely painful when he arrived, though it was clear that there was more to his inability to walk than a simple reluctance to do so. Neurological assessment showed that he had very weak leg movements in all four legs, though with one side of this body slightly more severely affected. This indicated a problem affecting the spinal cord in the upper to mid-part of his neck.

The best way assess the spinal cord is an MRI scan, which shows the tissues around the spine – and the spinal cord itself – in far more detail than simple X-rays. This was the best way forward for Eric and his condition was felt severe enough to require a scan the same day. This showed a pinch-point between the first two bones of the spinal column – the atlas and the axis – with severe bruising of the spinal cord at this point. This represents atlantoaxial subluxation and is caused when this region of the neck develops abnormally, allowing a greater range of movement between the two bones, with this instability putting Eric at risk of damage to the spinal cord and nerves in this region. This often causes intermittent pain but in severe cases the spinal cord is damaged to the extent that dogs can be paralysed.

Although some dogs can get better with a period of rest, painkillers and sometimes using a neck brace, Eric’s recurrent problems and his profound weakness meant that surgery was the best option. Precisely how to stabilise the bones and allow the spinal cord to recover is a thorny problem. Affected dogs are small, there are several delicate structures in the area – including the spinal cord and some major blood vessels running alongside the spine – and any fixation needs to strong enough to keep the problem in check for the rest of his life. This leaves very little margin for error.

 

The top image shows a lengthways view through Eric’s neck, with a pinch-point clearly seen affecting the spinal cord just behind his skull. The lower images are cross sections through the spinal cord at the levels indicated by the arrows – the one on the left showing severe spinal cord compression and bruising and the one on the right showing an adjacent region at it should look, without compression. The spinal cord in each case is marked by an asterisk.

To improve Eric’s chances of recovery, some custom-made guides were made to ensure that screws could be placed with maximum precision. He had a CT scan to map the surface contours of the bones in his neck and some bespoke 3D guides were printed to ensure that holes were drilled in the correct place. Once these were ready, Eric underwent surgery in which two screws were place in the atlas and three in the axis, with bone cement used to encase the area and keep it rigid. The cartilage in the joint between the two bones – the atlantoaxial joint – was surgically removed and the joint was packed with demineralised bone matrix to stimulate fusion of the two bones and ensure lifelong rigidity.

Eric was more comfortable within 24 hours of the operation. By the following day he was no longer needing injectable painkillers and was also starting to move his legs better. He went home within two days of the operation, not yet walking but much improved and far more comfortable than he had been. Eric was able to walk independently within 10 days and he continued to improve following this, becoming steadily stronger and gradually returning to his pre-injury playful self. Take a look at the recent videos of Eric below, living life to the full.

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