The presence of pain perception in Intervertebral Disc Disease (IVDD) is the most important prognostic factor when making a decision about treatment. All dogs with intact pain perception have the potential to recover motor function and continence. It is appropriate to refer any dog that cannot walk.

Intervertebral disc herniation can be treated conservatively with medical management or surgically*. Conservative treatment for both thoracolumbar and cervical disc herniations includes strict cage confinement for a minimum of two weeks. During this time, they can be taken out (with support) to urinate and defecate three to four times a day. Additionally, passive range of motion exercises can be performed. After two weeks, the amount of controlled exercise the dog can do when it is taken out, can be increased slowly. The dog must remain on a leash, supported by a sling (or cart) if needed, and walking only.  It must still be confined and supervised, when not performing exercises. 

Pain can be managed with NSAIDs and opiates. Muscle relaxants e.g. diazepam or methocarbamol are helpful with neck pain as much of the pain is due to muscle spasm. Anti-inflammatory doses of corticosteroids (0.25 – 0.5mg/kg/day of prednisone) can be used in dogs with neck pain once the diagnosis is confirmed, but are not typically necessary for back pain, and should not be used without cage confinement. The dog should be evaluated regularly for any deterioration in neurologic status, or lack of improvement over 2 weeks, both of which indicate treatment failure. If the dog has motor function it should be able to urinate on its own. If improvement is seen after 2 weeks, the conservative route can be pursued and the dog transitioned to normal activity (excluding jumping, twisting) by a very gradual increase in exercise.

Conservatively managed patients tend to recover more slowly and to a lower level and have an increased risk of occurrence. Conservative treatment is aimed to prevent re-injury to allow the spinal cord to recover. You must remember – the spinal cord is not decompressed.

The prognosis for recovery treating patients conservatively with Grades I and II IVDD are 80-90%. Grade III patients have greater than 70% chance to recover. Grade IV patients have approximately a 50% chance to recover with conservative treatment. Unfortunately, Grade V cases have less than a 5% chance to recover.  Assisi Animal Health’s Loops, with their PEMF technology, have been used successfully in two IVDD trials, with published results (see below).

The goal of surgery is to decompress the spinal cord and reduce the risk of recurrence. It is recommended for Grades III – V disease (non-ambulatory, paraparesis or paraplegic) and imperative for grade V disease (paraplegic without pain perception). Surgery is also acceptable after recurrent bouts of pain in Grades I (pain only) & II (ataxia and paraparesis) disease. Post-op management is the same as with conservative treatment.

The prognosis for recovery treating Grades I, II and III patients surgically is greater than 90%, while Grade IV is about 90%. Grade V patients treated surgically have about a 50% chance to recover.

There is little evidence on a perfect window in which surgery should be performed. Current thoughts are to do surgery on any dog that cannot walk within 24 hours. For dogs without pain perception cut within eight hours. While published data does not show an effect of timing of surgery, new data suggests delaying surgery increases the risk for myelomalacia.

Post-operatively evaluating cutaneous trunci muscle response has been shown to be an early predictor of outcome. Trace the caudal border of the CTM and report if it moves cranially, caudally, or stays static. Cranial movement of the CTM is significantly associated with developing ascending myelomalacia. Caudal movement of the border is associated with improvement.

*Spinal shock is the loss of muscle tone and segmental spinal reflexes that develop caudal to a severe spinal cord injury. Although little recognized in the veterinary literature, spinal shock occurs in animals and is important in both accurate lesion localization and case management. This is particularly important for veterinarians in primary care centers who are likely to see animals in immediate post-injury period when spinal shock is most marked. Spinal cord trauma damages spinal arterioles and abolishes this intrinsic regulation. Spinal cord perfusion becomes dependent on mean arterial pressure and is therefore poor during spinal shock. The initial spinal injury can be markedly worsened as ischemia and hypoxia develop. Spinal shock persists for a variable length of time followed by a gradual return of reflexes.

Assisi Animal Health’s Loop has participated in two IVDD trials, one at North Carolina State University’s College of Veterinary Medicine, and one at Animal Medical Center, NY. The Assisi Loop, with its PEMF technology, was used to control pain and inflammation and to facilitate wound healing. Pet owners noted when dogs were returned to home care, that their continued use of the Loop at home, resulted in the use of 50% less drugs.

Next week we will discuss post-operative management of IVDD.