By Dr. Becker
There are two types of pain: helpful and unhelpful. Helpful, or adaptive pain, aids in survival by protecting us from injury. It also supports the healing process when an injury has occurred.
Maladaptive pain, by contrast, is unhelpful. According to Clifford Woolf of Harvard Medical School, maladaptive pain is "… an expression of the pathologic operation of the nervous system; it is pain as a disease." It is pain with no useful purpose resulting from abnormal functioning of the nervous system.
Pain is typically a symptom of a disorder, but maladaptive pain is its own disorder.
It can arise from damage to the nervous system, which is neuropathic pain. It can also occur where there is no damage or inflammation, in which case it's dysfunctional pain. In humans, dysfunctional pain is seen in conditions like irritable bowel syndrome, TMJ, interstitial cystitis and other disorders in which there can be a great deal of pain, but little or no detectable reason for it.
Dr. Woolf offers this analogy:
"… if pain were a fire alarm, the nociceptive [adaptive] type would be activated appropriately only by the presence of intense heat, inflammatory pain [also adaptive] would be activated by warm temperatures, and pathological [maladaptive] pain would be a false alarm caused by malfunction of the system itself. The net effect in all three cases is the sensation we call pain. However, because the processes that drive each are quite different, treatments must be targeted at the distinct mechanisms responsible."
According to a column in this month's Clinician's Brief (published by the North American Veterinary Conference or NAVC), Payton is a large Labrador retriever mix surrendered to a shelter and adopted by a new owner.
According to Payton's previous owner, the dog had been limping on her right rear leg for about a year and a half. Payton had not been seen by a vet for the limp, nor was any treatment given.
When she arrived at the Downing Center for Animal Pain Management in Windsor, Colorado, Payton weighed about 100 pounds. Her body condition was average – she was not overweight. She had significant right rear leg lameness with severe atrophy of the right thigh muscles.
After a thorough pain examination by palpation, Payton was diagnosed with complete cranial cruciate ligament (CCL) rupture of the right knee, and partial tear of the left knee. Osteoarthritis was also present in the injured joints. Payton's pain level score was assessed at a 5 on a scale of 1 to 10.
The cruciate ligaments are bands of fibrous tissue, two per knee, which connect the bone above (femur) and below (tibia) the knee joint. The bands cross over each other – one band runs from the inside to the outside of the knee joint and the other runs outside to inside.
Typically one of three things causes a tear or break in the cranial (anterior) cruciate ligament:
- Trauma from a fall, being hit by a car, or even changing direction while running
- A floating kneecap (luxating patella) that slips out of place
When the CCL tears or ruptures, the knee bones no longer move normally and your pet will have a hard time putting weight on the leg without it collapsing. That's because the tibia is no longer supported by the cruciate ligament and thrusts forward when any weight is exerted on the leg.
The condition is painful for the animal, and without proper treatment, permanent joint damage can result.
Payton's Treatment Plan
In partnership with Payton's new owners, the veterinarian in charge of the dog's care decided (very wisely, in my opinion) against immediate surgery.
Instead, she developed a more conservative strategy to accomplish three things:
- Control pain
- Support and improve joint health
- Restore function and strength to the injured leg
Payton's long-standing, untreated ligament damage meant she walked around lame for a year and a half. In trying to compensate for her painful leg, she moved her body awkwardly and ultimately developed maladaptive pain low on her back near her tail.
Before attempting to rehabilitate an animal's injury, ethics (and simple kindness) require pain control as a first step. Since Payton had no way to communicate when she was hurting or to what degree, the first step in treatment was pain management.
The doctor in charge of Payton's care prescribed meloxicam, a non-steroidal anti-inflammatory drug (NSAID). Also prescribed was gabapentin, a medication used to relieve neuropathic pain.
The NSAID was used to control the pain of the CCL injuries, and the gabapentin was given to alleviate Payton's maladaptive low back pain. At my hospital, we incorporate natural anti-inflammatories as well, including:
Payton also received Adequan injections. Adequan helps slow joint degeneration and promotes joint fluid production.
Payton's diet prior to treatment at the pain clinic had consisted of commercial dry dog food.
As part of her recovery, the vet put her on a commercial prescription diet marketed as specific for joint support. Since Payton's weight was good, there was no need to reduce her caloric intake.
Needless to say, this wouldn't be my approach. I would transition Payton, at her own pace, to a balanced, species appropriate diet. I would supplement with Egg Shell Membrane, Glucosamine Sulfate, MSM and Cetyl Meristoleate.
Carbohydrates (corn, wheat, rice, soy, millet and even potato) are pro-inflammatory foods; they promote inflammation. I recommend a naturally anti-inflammatory diet for animals with musculoskeletal issues to naturally help reduce, rather than foster, additional inflammation.
Payton's pain score and function was assessed twice during the first month of treatment. At the end of the month, her pain score was stable at 1 out of 10 and her right rear leg lameness was also significantly improved.
Payton then began a physical rehab program to improve function and rebuild strength.
She used an underwater treadmill, which helped build strength with little to no discomfort. The water supported Payton's body so she could exercise in a normal posture without putting weight on damaged joints. Water also provides resistance during movement, which strengthens muscles.
As her strength increased, Payton's owners increased the length of her walks at home from 10-15 minutes once or twice a day. They added 10 minutes every two weeks until each walk was an hour in length.
After 16 weeks of therapy, Payton's pain score was a nice, round zero.
During this time, Payton also received laser therapy to help with persistent pain at the thoracolumbar junction. Laser therapy is useful for treatment of osteoarthritis, among other things.
At my practice, we also incorporate acupuncture and electro-acupuncture to help reduce joint pain.
Payton went from monthly pain assessments to a reassessment every eight weeks.
The dosage of meloxicam she received was reduced after three months of treatment, reduced again after four months, and discontinued at the five month mark.
The gabapentin dosage was decreased a month after the meloxicam was discontinued, was reduced again every two months and discontinued after six months. This drug, used to deal with the maladaptive back pain Payton suffered, was decreased more slowly than the NSAID to prevent a pain rebound.
Payton remains on the commercial prescribed diet for joint support (again, this would not be my choice of nutrition for any dog). She continues to receive twice-per-month Adequan injections, a glucosamine/chondroitin supplement, and an avocado-soybean unsaponifiables (ASU) supplement.
A word about ASU:
Because there are relatively few trademarked and widely accepted products for veterinary use, the few that have been marketed tend to be the only option traditional veterinarians prescribe, including Dasuquin™ by Nutramax Labs.
There is absolutely nothing wrong with this product (although I don't recommend soybean anything for pets) -- it's safe and fine to use. Because it's one of the few extensively marketed pet joint support products, it tends to be the only one vets reach for. There are many other superior-quality joint products available, but you'll have to do your research, as they are not heavily marketed. You can start by researching 'perna mussel,' 'egg shell membrane,' etc. online. I use several human products at my practice as I feel human supplements are often better quality.
Payton has returned to full activity. She walks 12 to 20 miles per week and shows no right rear limb lameness. Her pain score remains at zero.
Surgery to repair the right CCL rupture was avoided, and there has been no further apparent degeneration of the left knee joint. This case is an example of the best-case scenario of avoiding surgery through rehabilitation.
It's important to note that surgery was avoided because of the intense rehabilitation this patient underwent. Even with intense therapy, many animals end up requiring CCL surgery to continue with superior quality of life. In this situation, the patient was able to compensate adequately enough through the strengthening and conditioning of muscles that she could exist with no CCL ligament. It's important to remember that not all animals fare as well.
Payton's case is a great example of using a multimodal approach – without surgery -- to manage both 'real' and maladaptive pain and return a pet to full function.
Every patient and situation is different, so the challenge is always finding which methods of treatment are most suitable and helpful for the individual pet and his or her family.