Epidural Injections
Epidural Injection for Management of Caudal Lumbar Pain
Some dogs, like some people, have significant lower back pain. Often it is due to posture and subsequent muscle soreness. In some cases it is due to narrowing of the spinal canal itself or the boney channels (foramen) from which nerves exit to the limbs. This narrowing causes compression or pinching of the nerves in this region resulting in pain and sometimes neurologic deficits like weakness, stumbling, and incontinence.
The symptoms of back pain in dogs include slowing down or reluctance on walks, especially uphill. Decreased willingness to go up stairs, jump onto furniture or into the car are common. The muscles of the back are typically tight and spasm. Sometimes the overlying skin is twitchy when touched. With pressure over the spine some dogs exhibit signs of pain such as wincing, sinking, turning or even whining.
A common site for narrowing in the lower lumbar spine is the lumbosacral space. Compare the 2 radiographs to the right. The red arrow indicates severe changes in the lumbosacral joint and when coupled with the proper signs supports the diagnosis. Importantly, not all dogs with radiographic changes have narrowing of the canals, but many do. The best way to be certain is with MRI or a dynamic CT scan. Short of this clinical impression, ruling out other causes like hip pain, and radiographs can help with diagnosis.
Lumbosacral stenosis can be treated medically with oral medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, gabapentin, and amantadine. Physical rehabilitation, LASER, acupuncture, and shockwave therapy can also help. For some dogs epidural injection with steroid is the most helpful therapy. Dr. Mich utilizes all of these treatments in managing lower lumbar pain in dogs. In dogs with unrelenting pain or significant neurologic deficits surgery may be helpful and these patients are referred to a neurosurgeon.
Lumbosacral (epidural) injection procedure:
This is a common procedure used for providing pain management for routine surgical procedures of the hind limbs using an opioid +/- local anesthetic. Dr. Mich, as a board-certified anesthesiologist, has performed hundreds of epidural injections for surgical procedures. In the case of lower lumbar pain the medication injected is a corticosteroid, which can shrink swelling and inflammation around the compressed nerves relieving pressure. The procedure is performed under heavy sedation and using radiographs to guide the exact placement of the spinal needle. A dye is used to confirm placement before medication is injected. See the images below. The site is located between the wings of the hips in the lower back (yellow arrow).
Efficacy of the Procedure for Managing Symptoms
Steroid injection for the management of nerve pain has been used in human medicine for many decades. In veterinary medicine it has been used less frequently although studies have been published on this technique and Dr. Mich has used steroid injection successfully in managing pain associated with lower lumbar and lumbosacral disease primarily.
Dr. Mich requires a clinical assessment and screening radiographs prior to performing the injection. This can be done day of the procedure (usually) or before. This is to help rule out serious issues such as discospondylitis (an infection of the disc space) and neoplasia (tumors) affecting the bones in the region. Either of these can cause symptoms similar to pain from other lumbar compressive conditions such as disc disease and facet osteoarthritis. Should these conditions exist, epidural injection will not be performed. Notably x-rays are not able to detect all conditions affecting the region. MRI and CT are able to rule out pathology within and around the spinal cord most definitively.
As is true in human medicine the efficacy (ability to improve clinical signs) is not known ahead of time. Some patients improve and some do not. Dr. Mich typically provides a 2-injection series 3-4 weeks apart. If there is not improvement after the second injection no further injections are advised. If there is response, duration of response varies from days to weeks to many months. This is true in human patients as well. Injections can be repeated every 3-4 months usually as a single injection and not a series.
It is important to couple this treatment with other supportive treatments like weight management, physical rehabilitation among others. Dr. Mich provides patients with lower lumbar pain a comprehensive treatment plan.
For a case example see Henry’s story
