Lumbosacral Conditions in Dogs

Diagnosing and treating lumbosacral (LS) pain can become a frustrating experience for veterinary practitioners.

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Integrative Medical Considerations

by Narda G. Robinson, DO, DVM, MS, FAAMA, and Mike Petty, DVM, CCRT, CVPP, DAAPM

Introduction

Diagnosing and treating lumbosacral (LS) pain can become a frustrating experience for veterinary practitioners. Many conditions present with one or all of the following signs: ataxia, paresis, paralysis, loss of normal neurologic reflexes, and pain. In this article, we seek to achieve two aims: 1) Assist veterinarians in investigating the cause of LS disease or dysfunction, and 2) Consider nonsurgical treatment options with a special emphasis on integrative medicine and rehabilitation measures.

LS Disease

CS5.jpgThese plates identify muscles of the superficial (Plate 1, top) and deep layers (Plate 2, bottom) as a reminder of the interconnectedness of the LS region with numerous other structures, including the thoracolumbar fascia (the white diamond outlined in Plate 1.

The term “LS disease” describes an array of disorders that likely include the L7-S1 junction but typically affect the caudal back and sacral region more broadly.

Given the prominent neurovascular structures in the pelvis, one could see neurologic involvement as in cauda equina syndrome (CES) and LS stenosis; myofascial dysfunction; degeneration of intervertebral disks, ligaments, and bone; tenderness to palpation; postural abnormalities; gait disturbances; and biomechanical compensatory patterns. See Box 1 for additional differentials.

Regardless of the etiology, practitioners could more precisely identify sources of pain and mechanical dysfunction by improving their evaluation. They could also “up their game,” that is, offer more complete care and pain resolution by including science-based integrative medicine and rehabilitation modalities in their treatment plan. See Table 1 for ideas on including methodologies such as medical acupuncture, massage, photomedicine, and rehabilitation to improve outcomes and help reduce the need for surgery.

Diagnosis

Without advanced imaging and diagnostic procedures such as magnetic resonance imaging (MRI), computed tomography (CT), and lumbar puncture, the primary care practitioner may not be able to fully characterize the underlying problems. For many dog owners, the cost of these diagnostics may be beyond their financial reach, and in most cases, one could institute an integrative medicine sequence to determine whether the condition appears to respond. The good news is that when dogs are presented with lumbosacral issues, the same therapies can be applied to all of them; only those dogs who do not improve with therapy typically need further testing.

For this article, we are going to primarily look at the diagnosis and treatment of three similar presentations: LS disease, intervertebral disc disease (IVDD), and degenerative myelopathy (DM). Every diagnosis starts with a good clinical history. Allopathic medicine tends to jump right into an exam and lab tests. Most of us do not take the time to start with a thorough history, beginning with what is going on in the animal’s home life. For example, did you recently move to a new house with stairs or wood floors? Did a new animal join the household that might be “roughhousing” with the patient? Has a new person taken over as the dog’s primary caregiver?

All of these things can impact a pre-existing condition (having to use stairs, for example) or cause a new one (an injury from roughhousing). And, of course, we should ask the usual history questions about trauma, onset, previous episodes, previous surgery, urinary or fecal incontinence, trouble positioning or experiencing pain during defecation or urination, and so on.

After acquiring a thorough history, our key next steps include observation, physical examination, and a comprehensive myofascial palpation to identify areas of myofascial restriction and tenderness. Plates 1 and 2 identify muscles of the superficial and deep layers as a reminder of the interconnectedness of the LS region with numerous other structures, including the thoracolumbar fascia (the white diamond outlined in Plate 1 (Superficial Muscles).

Physical Exam

The physical exam begins with a hands-off distant observation. We look for postural abnormalities, movement alterations, and physical changes. All three conditions (LS disease, IVDD, and DM) may have similar presentations: clicking nails or knuckling of the back feet when walking, a limp tail or one that is tucked or less mobile, and difficulty changing positions.

If time permits, we prefer to begin our assessment as the dog exits the car and walks in from the parking area. This way, they are less guarded in hiding their pain. It also allows us to see them walk on nonslip surfaces. Continue observing the dog while discussing the history with the caregiver in the exam room. This may help to differentiate between signs of pain and neurologic involvement; you may find both.

Observational Signs

Too commonly, we tend to dismiss signs of pain and dysfunction as “behavioral” or idiosyncrasies of the patient. This uninformed attitude underestimates the amount of physical debility an animal is exhibiting and risks missing the opportunity to intervene meaningfully in their care. To help offset this habit, please review the list below and keep it handy as a reminder to evaluate these features each time you encounter a dog with suspected LS problems.

  • Signs of pain
  • Knuckling
  • Kyphosis
  • Moves whole back as a unit
  • Bilateral hind limb lameness
  • Wiggly butt; may have a “sashay” as the dog walks to avoid movement of lower back
  • Interrupted whole body shake (see Glossary)
  • Signs of a neurologic problem
  • Paresis/paralysis
  • Hair coat changes (see Glossary)
  • Particularly over the lumbosacral region
  • Flattened (most common), erect, or disheveled hair

Myofascial Palpation Evaluation

(See Plates 1 and 2 for muscular anatomy review.) With a whole-hand palpation applied in a slow, cross-fiber direction to each muscle/ myofascial structure, assess for areas of tenderness, restriction, or “noticing” from the animal as they may turn toward you, breathe a bit faster, or move away. The myofascial evaluation should approximate a massage. It should never be painful or induce fear. Rather, this opportunity should mark the beginning of a relationship of trust between the patient and the practitioner. Take your time, be thoughtful, examine each muscle from end to end, and record your findings to compare with future treatments. The integrative medicine measures outlined in Table 1 rely heavily on the myofascial palpation exam as a scientific approach that addresses actual physical and functional problems—not mystical, metaphorical, imaginary energies. During the exam, you might note symptoms such as:

  • Restrictions of the muscles in the lumbosacral region (entire pelvis, trunk, caudal abdomen, and pelvic limbs)
  • Fascial restrictions in the region
  • Tenderness to palpation
  • Especially over the LS junction
  • Warmth over LS region

Neurologic Exam

Many providers skip the neurologic exam or perform it ineptly. Learn to perform at least these three tests and do them well. Doing so will help you avoid misdiagnosing animals in the future.

1. Conscious proprioception (CP) determines whether the problem is neurologic. It does not localize the lesion.

  • To check for this, many practitioners will flip a foot upside down and let go. This leads to false negatives as dogs with loss of CP can still feel their foot, they just don’t know where it is in space (i.e., the conscious proprioception part!). To avoid this “touch” reaction, flip the foot upside down, hold it in place at least three seconds while supporting weight over that leg, then let go. If they immediately flip it right side up, then the CP is normal. If not, this indicates early neurologic problems—the inability of an animal to know where their foot is in space. This is often the first thing to go with any neurologic impairment.

Glossary

Interrupted Body Shake
Most dogs, when standing from a down position, will shake their entire body. However, if it hurts somewhere, they will either not shake that part or stop completely when they reach a painful area. For example, a dog with IVDD at the T/L junction will shake through most of the thorax but stop just before the junction. Another example is a dog with hip dysplasia. They will shake all of the way down their back but not their pelvis.

Hair Coat Changes
All vertebrae share pathways with organs, muscles, and skin. The observant practitioner may notice that the hair coat is flattened or disheveled over a portion of the spine that corresponds to a dysfunction at that part of the spinal cord.

Transitional Vertebrae
Discovering transitional vertebrae and what they mean can be an important diagnostic tool. When there is chronic irritation secondary to CES, oftentimes either the last lumbar vertebra will react by starting to look like the first sacral vertebra or the first sacral vertebra will start to look like a lumbar vertebra. The exact reason for this inflammatory response is unknown. Always take a lateral radiograph that includes the entire lumbar spine and sacral spine. Then, count the lumbar vertebrae, and if the number is either six or eight and the corresponding sacral vertebrae are either four or two, then this is pathognomonic for CES—no MRI necessary!

2. Crossed extensor reflex tests provides information about the presence of an upper motor neuron (UMN) lesion. The limb that straightens (and perhaps both will) to a pinch of the opposite limb’s toe (hence the term “crossed” extensor) is considered positive. Under normal circumstances, this reflex will be inhibited. Thus, an interruption in the integrity of connections within the spinal cord will allow this hardwired reflex to manifest.

Perform the test in the thoracic limbs and pelvic limbs. A positive crossed-extensor reflex in the thoracic limbs and the pelvic limbs suggests a UMN lesion in the neck but does not rule out additional lesions more caudal. A positive reflex only in the pelvic limbs indicates the possibility of a UMN lesion from T3 to L3. Finding evidence of a crossed extensor reflex does not mean that the animal requires surgery.

On the contrary, a comprehensive knowledge of the neurologic status of a patient informs the science-based integrative medicine provider and rehabilitation practitioner about where and how to most safely and judiciously address the problems.

  • A crossed extensor test involves putting a dog in lateral recumbency. A sharp pinch is given to the “down” paw while holding the “up” limb lightly in your hand. A normal reflex is to feel the “up” paw push down, even slightly. An abnormal reflex is to have no reaction whatsoever in the “up” paw.

3. Panniculus response is a twitching or crawling of the skin when it is stimulated with a small-gauge hypodermic or acupuncture needle in the paraspinal region. I start this test in the pelvic region and work my way up. If you can get all the way to the head and there is not panniculus, then the test is unreliable. But if you can consistently get the dog’s skin to react at the same point, that is the approximate area of the spinal lesion.

Laboratory Testing

It is always a good idea to run a basic panel on your patients with lumbosacral conditions. Not only do you need to know that they are healthy for any medications, botanicals, or supplements that you might want to dispense, but you also want to rule out problems that can mimic pain, such as the following.

  • Anemia can mimic ataxia.
  • Diabetes mellitus can cause diabetic neuropathy.
  • Any organ issue can cause a dysfunction in the shared myotome. Just like a person having a heart attack can feel arm pain, things like kidney disease and pancreatitis can exhibit pain in areas along the spine.

In addition, every dog with a lumbosacral condition should have a genetic test for degenerative myelopathy. It is a simple test that can be done in your clinic with a cotton swab, or you can have clients do it themselves and send it in.

Radiology

To best narrow the diagnosis, we prefer to obtain radiographs of the lumbar spine and LS junction. Although we can feel heat and see a pain reaction during palpation, we can’t immediately know what the issue is. Radiology can help us differentiate between

  • Spondylosis
  • Spondylitis
  • Osteosarcoma
  • Calcified and narrowed disc spaces indicating chronic or acute disc disease
  • Transitional vertebrae (see Glossary)

Specialty diagnostics are sometimes the last resort of the recalcitrant case, but rarely does the practitioner need to send an animal off if they are careful to follow the diagnostic steps previously listed.

Other Causes of
Caudal Back Issues

Cauda equina syndrome
⊲ Fibrocartilaginous embolism
⊲ Neoplasia
⊲ Spondylitis/osteomyelitis
⊲ Fracture/trauma
⊲ Hemivertebrae
⊲ Tick paralysis
⊲ Diabetic neuropathy
⊲ Toxoplamosis
⊲ Neospora caninum
⊲ Iliopsoas muscle dysfunction
⊲ Primary malignant neoplasm (e.g., osteosarcoma, fibrosarcoma, hemangiosarcoma, nerve sheath tumor)
⊲ Metastatic neoplasia (e.g., prostatic)
⊲ Polyarthropathies
⊲ Pelvic limb disorders (e.g., stifle dysfunction, coxofemoral degeneration or dysplasia)
⊲ Myasthenia gravis
⊲ Metabolic disorders leading to weakness
⊲ Inflammation
⊲ Fracture/luxation

Diagnosis of Three Featured Diseases

Degenerative Myelopathy (DM)
I am surprised by the number of dogs that come through my practice who have never been tested for DM. It is no longer considered a “German Shepherd disease.” It is also just about the least expensive diagnostic we can run and leaves no doubt when the results come in, positive or negative. However, there are some hallmarks of DM that will make you put this at the top of your differential list after your exam:

  • Slow onset of signs.
  • Although owners may think a dog is acting how it is from pain, it is usually a nonpainful disease. Look for neurologic issues as noted earlier.
  • When you do firm palpation at the L/S junction, most dogs with DM couldn’t care less. If it is a dog with cauda equina syndrome, they almost always react, sometimes dramatically.

Cauda Equina Syndrome (CES)
As just mentioned with the diagnostic description of DM, a painful response to palpation of the L/S junction puts CES high on my list of possibilities. These dogs may have both the neurologic signs of DM and the pain signs listed earlier. I rely heavily on radiographic changes to help confirm my diagnosis:

  • Presence of a transitional vertebra.
  • Spondylosis between L7 and S1, often more advanced than spondylosis elsewhere in the lumbar spine.
  • Sclerosis of the caudal endplate of L7 or the anterior endplate of S1. Sclerosing is usually seen as a bright white area of calcification and indicates some kind of chronic inflammation.

Intervertebral Disc Disease (IVDD)
In dogs, the spinal cord usually ends at L6, although variation is possible. This means that a narrow disc between L6 and L7 needs to be interpreted with caution before calling it IVDD. But a narrow or calcified disc further up the spinal column can mimic the pain and dysfunction of CES and the paresis seen in DM.

Treatments

Therapy for these conditions differ slightly, with treatment of CES and IVDD aimed toward reducing pain and maintaining or improving function and treatment of DM aimed more at preserving neurologic function and muscle mass as long as possible. With the advent of the use of medical acupuncture and physical rehabilitation therapy in veterinary medicine, the question of how to treat these dogs is receiving more intense scrutiny.

When presented with CES or IVDD a decade or more ago, it seemed that the only option we were told about was surgery—“a chance to cut is a chance to cure.” With acupuncture and rehab, and in the right hands, the outcomes of therapy are similar to that of surgery. And, of course, this avoids the cost, pain, and anatomic intrusion of spinal surgery. This doesn’t mean that surgery should be avoided at all costs, but it should be the last resort and not the first step. See Table 1 for an outline of how integrative rehabilitation modalities address specific components of LS dysfunction.

Pharmaceuticals can also help with the pain associated with CES and IVDD, and almost all of my cases are put on something. Because of the side effects of corticosteroids, I always reach for NSAIDs first. Most cases respond just fine to NSAIDs. Other common choices are gabapentin and amantadine, whose side effects can usually be managed with changes in dosing.

Degenerative myelopathy cases have a harder row to hoe when it comes to both treatment and prognosis. These cases progress no matter what we do, but we have the ability to slow that progression dramatically with acupuncture and physical rehabilitation. To date, no drugs have been shown to vastly improve the outcome of DM cases.

Conclusion

Every diagnosis starts with a good history and a complete physical examination. This is even more important when diagnosing conditions that can cause lower back pain or neurologic function. However, this often requires the primary care veterinarian to refresh themselves on different examination techniques and to know when to refer if they are unable to perform these techniques themselves.

Mike Petty
Mike Petty, DVM, CCRT, CVPP, DAAPM, is in private practice in Canton, Michigan. He is a frequent national and international lecturer on topics related to pain management. Petty offers commentary on each Pain Case of the Month.

 

Narda Robinson
Narda G. Robinson, DO, DVM, MS, FAAMA, is founder and CEO of CuraCore MED and CuraCore VET, a private continuing education company in Fort Collins, Colorado. Prior to launching her own educational institutions, Dr. Robinson taught science-based integrative medicine for two decades at Colorado State University’s College of Veterinary Medicine and Biomedical Sciences.

 

Photo credits: Photos courtesy of CuraCore VET

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