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Oklahoma State University
Center for Veterinary Health Sciences

Healthy Animals - Healthy People

Hansen Type I Cervical Intervertebral Disc Disease



The correlation between success of medical management for Hansen Type I cervical intervertebral disc disease with percentage of compressive myelopathy and resorption of herniated disc material using magnetic resonance imaging.

Hansen Type I Intervertebral Disc Disease (disc herniation) is one of the most common causes of myelopathy in dogs. Cervical IVDD occurs in about 13-25 percent of IVDD cases, while thoracolumbar accounts for the remainder. Treatment options for IVDD vary depending on the severity and progression of clinical signs; the prognosis, and potentially the best course of treatment, is based on clinical and/or diagnostic findings.

It is common for patients with cervical IVDD to present with severe pain only; 15-61 percent of patients with cervical IVDD present with cervical hyperesthesia, guarding of the neck, and muscle fasiculations without evidence of neurologic deficits. Medical management is reserved for patients who exhibit acute pain only with or without minimal neurologic deficits, such as delay or loss of proprioception, patients who exhibit paresis, but are strongly ambulatory, or when financial constraints are present. Although MRI has been utilized as a sensitive diagnostic tool to characterize and evaluate severity of IVDD compressive myelopathy, it has not been prospectively used to evaluate the likelihood that medically managed cervical myelopathy secondary to IVDD would improve. Retrospective evaluations suggest that patients with pain, with or without mild neurologic deficits, would have a higher likelihood of improving with medical management than those with more severe clinical signs. The goal of this study is to prospectively determine whether or not medical management of cervical IVDD is likely to be successful based upon percentage of spinal cord compression. Also, the study will determine if there is a correlation between degree of resorption of disc material and clinical outcomes with medical management.

Eligible Candidates

Candidates for this study will include those who are currently suffering from an acute episode of Hansen Type I Cervical Intervertebral Disc Disease and fit criteria for medical management of their condition.

Patients who can be included in this study must fit the following criteria:

  • The patient must not be any worse neurologically than ambulatory tetraparesis with varying degrees of ataxia.
  • The patient must have an acute episode that has been present for approximately 2 weeks. The best patients who will fit this study are those that have an acute event to where the owners present to your clinic for sudden pain, neurologic deficits, and have not been receiving long term pain medications prior to your examination.

If you have a patient who fits the criteria of medical management for a presumed cervical disc extrusion (Hansen Type I IVDD), we ask that you consider offering them to come to OSU.

Patients Included in the Study

  • The patient will receive an exam, up to three nights hospitalization to control more severe pain if needed, pain medications, and an MRI scan (including anesthesia) at the time of appointment ($1,500-2,000 value).
  • The patient will be sent home for continued medical management (as you would have initiated prior to the patient arriving at OSU). We will recommend a pain management protocol for consistency amongst the patients enrolled in the study. Our pain management protocol will consist of tramadol (3-5mg/kg PO TID), carprofen (2.2mg/kg PO BID) or an alternative NSAID based on your preference, +/- gabapentin (5mg/kg PO TID), if needed. Therefore, if you see a patient and are interested in sending them up to OSU, we ask that you provide the patient with this pain management protocol prior to their arrival, if possible.
  • The patient will receive a second, free MRI scan ($1,400) 12 weeks after recovery from medical management; or if medical management fails greater than 4 weeks after the first MRI scan.


For more information or to refer a patient for evaluation and possible inclusion in this clinical trial, please contact Dr. Danielle Dugat at the Boren Veterinary Medical Hospital 405-744-7000.