Case Study- tethered cord syndrome and DLSS- meet Siu q

At Hong Kong Veterinary Specialty Services, we recently treated Siu Q, an 8-year-old Pembroke Welsh Corgi presenting with progressive pelvic-limb weakness, knuckling and difficulty walking.
Siu Q was initially known to have severe left hip osteoarthritis, but her neurological abnormalities — particularly marked proprioceptive deficits, absent patellar reflexes and lumbar pain — could not be explained by hip disease alone. This prompted us to investigate for a concurrent neurological disorder.

Investigation

MRI of the thoracolumbar and lumbosacral spine identified degenerative lumbosacral disease with L7 nerve-root/foraminal compression, together with findings highly suspicious for tethered cord syndrome (TCS). The conus medullaris extended unusually far caudally towards the lumbosacral junction and followed an abnormal dorsal course.
Degenerative lumbosacral stenosis (DLSS) develops when degenerative changes around the L7–S1 junction narrow the vertebral canal and/or intervertebral foramina. Compression of the L7 nerve roots and cauda equina can result in pain, weakness and neurological deficits.
Tethered cord syndrome, in contrast, occurs when the distal spinal cord is abnormally anchored by fibrous tissue or other attachments. Instead of moving freely within the vertebral canal, the spinal cord and associated neural structures are subjected to chronic traction. This tension may progressively impair neural function, producing pain, weakness and proprioceptive abnormalities.

Surgical treatment

Because imaging can strongly suggest TCS but may not demonstrate the exact tethering structure, surgical exploration was undertaken.
A dorsal laminectomy allowed direct examination of the lumbosacral neural structures. Intraoperatively, we identified three distinct fibrous ligamentous bands tethering the neural tissues over the cauda equina, confirming the diagnosis of tethered cord syndrome. Each band was carefully isolated and divided, visibly releasing the neural structures from their abnormal attachment.
We then addressed the concurrent DLSS using bilateral L7–sacral pedicle screw and rod stabilisation. The construct was designed to maintain distraction of the lumbosacral foramina, helping to reduce compression of the exiting L7 nerve roots while stabilising the operated region. Postoperative radiographs confirmed appropriate implant positioning and opening of the foramina.
The intraoperative photograph shown here highlights the delicate neural structures encountered during the procedure.
Cases like Siu Q's demonstrate why neurological examination and advanced imaging are so important when orthopaedic and neurological disease coexist. Severe joint disease may explain pain and lameness, but findings such as knuckling and loss of proprioception should prompt investigation for neurological disease as well.

We wish Siu Q a smooth rehabilitation and recovery.