Lumbosacral (LS) Disease

Patients suffering from LS disease generally present with either intense lower back pain or pain/lameness involving one rear leg (root signature sign). These patients often show moderate to severe pain upon attempting to stand from a laying position or lying down from a standing position. Compression over the LS region (lordosis test) or extension of the hips or lower back will also cause discomfort. Some dogs can present for what appears to be an intermittent to continual lameness. Symptoms can result from one of several possible abnormalities which include: rupture of the LS disc space, instability of L7 in relationship to the sacrum, soft tissue or bony proliferation in the L7 - S1 foramen causing nerve root pain.

Diagnosis of LS disease often requires MRI imaging and/or a CT scan. The DVSC currently recommends a dynamic MRI study (an MRI performed in both a neutral as well as in a flexed position) to identify if the patient has a disc rupture, compression of a nerve root or instability. In our opinion, there are different forms of LS disease and each one requires a different treatment and surgical technique.

Surgical options to manage LS disease include:

1. dorsal laminectomy to remove a herniated disc,
2. foramenotomy or facetectomy to relieve an entrapped L7 nerve root, or
3. distraction and fusion of the LS region using a combination of a dorsal laminectomy, bone graft, facet screws and possibly a spinal arch or external fixator.

There is more evidence and agreement amongst surgeons that LS instability may play a large role in the pathogenesis of LS disease requiring fusion of the LS disc space to eliminate pain.

Intraoperative fluoroscopy allows accurate and safe placement of orthopedic implants into the L7 - S1 facet and vertebral bodies. Generally the prognosis after surgery is favorable. However, these patients will require a “quieter life style” for the remainder of their lives.

View/download this topic in our newsletter, Cutting Edge, Fall 2007.