Neuropathic pain is caused by a lesion or disease of the nervous system. It is often refractory to many commonly prescribed analgesic drugs. Common causes in veterinary patients include caudal occipital malformation syndrome (COMS), intervertebral disk disease, lumbosacral stenosis, nerve sheath neoplasm, and trauma, among others.

There are currently no validated neuropathic pain scales in veterinary medicine. The Comparative Pain Program is developing such a scale to facilitate the diagnosis and treatment of neuropathic pain in dogs and cats.

Do you have a patient suffering from neuropathic pain? You may be able to contribute to the development of the first veterinary neuropathic pain scale. Please contact us to provide us with information about the case. If you are seeking a consultation on a neuropathic pain case or would like to refer a patient with neuropathic pain to the Cornell University Hospital for Animals, please refer to the Clinical Service page.

Post-Amputation Pain and the Companion Animal Post-Amputation Pain (CAMPPAIN) Initiative

In people, post-amputation pain (PAP) is divided into phantom limb pain (PLP, pain perceived in a missing limb or other body part) and residual limb pain (RLP, pain perceived in the residual limb). PLP is an incompletely understood, complex pain state involving the central and peripheral nervous systems (CNS); it has a neurophysiological basis and is not solely psychogenic as once thought. In contrast, RLP can have both nociceptive (i.e., caused by nociceptor stimulation in the residual limb) and neuropathic components. Both PLP and RLP aredifferent from the postoperative nociceptive pain caused by surgical tissue handling in all patients.

In general, amputation in dogs and cats (which may be performed due to such problems as neoplasia, trauma, or infection) produces positive outcomes. Most patients are comfortable and fully functional shortly after surgery, and most owners are satisfied with their decision to amputate. However, in a subpopulation of canine and feline amputees, behavioral changes have been reported post-operatively that may reflect the presence of post-amputation pain (PAP). These may include:

• Sudden, unprovoked vocalization
• Sudden episodes or panic or anxiety
• Compulsive grooming or even self-trauma to the residual limb or tail
• Restlessness or difficulty getting comfortable or sleeping

The Comparative Pain Program is leading the CAMPPAIN Initiative, an international, multi-center study of canine and feline amputees. This prospective study aims to determine the incidence of behavioral changes consistent with PAP in dogs and cats and determine risk factors for such behaviors. To do so, the principal investigators collect the following information from all canine and feline amputees enrolled in the study:

• Medical history, including medications
• Physical examination findings
• Diagnostic test results
• Reason for amputation
• Length of anesthesia and anesthetic/ analgesic drug protocol, including regional anesthetic techniques and post-operative analgesic protocol
• Length of surgery, surgical technique, and surgical complications
• Incidence of specific behaviors post-operatively that were not present pre-operatively
  • Owners fill out an online questionnaire once weekly for six weeks post-operatively.

The research also involves the collection of blood and tissue samples, magnetic resonance imaging (MRI), and quantitative sensory testing.