Professor Ben -A Valiel Raphael

Pain that is defined as "a direct result of a lesion or disease affecting the somatosensory system." The lesion or disease may be physical damage, infection, or disease and may occur in the central or peripheral nervous system. Lesions and diseases include metabolic diseases (e.g., diabetic neuropathy), neurodegenerative, hypoxic, or autoimmune conditions, tumor, trauma, infection, exposure to toxins, or hereditary disease. Paradoxically, lesions or diseases involving the somatosensory nervous system may lead to loss of function (e.g., numbness) and the development of chronic pain accompanied by the development of increased sensitivity to pain and other sensory changes. Neuropathic pain is usually chronic, meaning that it is continuous or manifests itself in recurrent painful attacks.

There are very important non-painful neuropathies in which the same diseases and injuries described above cause loss or change in sensory function without pain. There are also some serious conditions that can lead to this and you should report any non-painful changes to your doctor immediately.

Within the family of neuropathic pain, my research group has studied two entities in particular. The first is trigeminal neuralgia, which can mimic a number of other diseases, especially dental. This is especially true when the neuralgia presents in atypical forms, and my research group has published extensively on this in order to minimize misdiagnosis in patients, which usually leads to incorrect treatments. Typically, the pain in TN appears after mild, painless stimulation of the face or mouth - see the video below. The stimulation can be talking, eating, brushing teeth, shaving, or even blowing on the face. The pain that is created is disproportionate to the stimulation and is very intense and lasts from a few seconds to about 2 minutes. The course is chronic with little chance of self-healing and therefore requires treatment. There are several drug, surgical, and radiation treatments, each with advantages and disadvantages. Treatment should be tailored to the patient's age, medical condition, occupation, and personal preference. These should be discussed carefully in order to choose the most appropriate one for your individual patient.

The second neuropathic pain, first described and accurately classified by my research group, is painful posttraumatic trigeminal neuropathy (PTTN). It is acquired as a result of nerve damage from multiple sources as shown in the diagram below. This entity has often been confused with trigeminal neuralgia and therefore has not been treated appropriately. The pain begins shortly after the injury and is localized within the area of injury or nerve area. It is usually persistent and occurs daily for hours. The intensity is moderate to severe and it feels like a “burning”. The pain is accompanied by adjacent areas where the sensation is abnormal – touch is not sharp or light touch is very painful. These are typical signs of neuropathic pain.