Trigeminal Neuropathic Pain And Trigeminal Neuralgia

What Is Trigeminal Neuralgia?

Trigeminal neuralgia is a severely painful condition that affects the face in the distribution of one of more divisions of the trigeminal nerve. The trigeminal nerve has three divisions: ophthalmic/V1, maxillary/V2, and mandibular/V3. In trigeminal neuralgia the maxillary and mandibular divisions are more likely to be affected. The pain typically affects one side of the face, and rarely, both sides. Most patients with trigeminal neuralgia are over 50 years old.

What Are the Symptoms of Trigeminal Neuralgia?

Patients typically describe their pain as a severe, sharp-shooting, electric-like-shock pain that lasts a few seconds to two minutes and occurs multiple times during the day. The pain is triggered by stimuli that would not normally cause pain such as brushing teeth, washing face, applying makeup or touching a tooth.

50% of patients have a trigger spot that, once touched, triggers their pain. Some patients may experience remission periods: days to years during which little or no pain occurs.

In addition to the severe attacks of pain, some patients may experience a continuous pain between attacks, which may be aching, throbbing, or burning in character.

What Causes Trigeminal Neuralgia?

Classical trigeminal neuralgia is caused by compression of the trigeminal nerve by an overlying blood vessel. This leads to deformation of the nerve which alters the conduction of nerve impulses.

Secondary trigeminal neuralgia results when the painful symptoms are caused by other conditions that affect the trigeminal nerve such as multiple sclerosis or invasive brain tumors that trap the nerve against adjacent structures.

In idiopathic trigeminal neuralgia, no identifiable cause for the symptoms would be detected.

How Is Trigeminal Neuralgia Diagnosed?

The diagnosis is based on a detailed clinical history and examination. The clinical history will include multiple questions about the location, quality, duration, frequency of the pain. Aggravating and alleviating factors that influence the pain will also be noted.

The clinical examination will include a general examination of the head and neck, a cranial nerve evaluation, a musculoskeletal evaluation, and a dental examination.

An MRI of the brain is typically recommended to verify if there is impingement of the trigeminal nerve by an artery and to rule out other disorders that can present with features similar to trigeminal neuralgia such as brain tumor and multiple sclerosis.

How Is Trigeminal Neuralgia Treated?

Treatment is initiated with anticonvulsant medications that are used for neuropathic pain conditions. Other treatment modalities for patients who fail medication therapy include surgery and gamma knife radiosurgery.

Trigeminal Neuropathic Pain

Neuropathic pain arises from injury, disease, or dysfunction of the peripheral or central nervous system.

Post-Traumatic Trigeminal Neuropathic Pain

Dental treatment can lead to damage to adjacent nerves resulting in altered sensation and trigeminal neuropathic pain. The onset of post-traumatic trigeminal neuropathic pain is frequently associated with minor surgical and invasive dental procedures. It is described as a unilateral or bilateral facial pain caused by trauma to the trigeminal nerves, presenting with other symptoms and signs of trigeminal nerve dysfunction, and persisting or recurring for more than 3 months. (ICOP 2020).

Dental Treatment Associated With Post-Traumatic Trigeminal Neuropathic Pain Include:

• Root canal treatment
• Extractions
• Implants
• Other surgical procedures

Idiopathic Trigeminal Neuropathic Pain

This refers to trigeminal neuropathic pain that occurs in the absence of any trauma or other identifiable etiology such as dental disease. Clinical and radiographic evaluation exclude local causes of the pain. It is also known as Persistent Idiopathic Facial Pain.

What Are the Symptoms of Trigeminal Neuropathic Pain

• Constant dull, achy, throbbing or burning pain
• Pain of moderate to severe intensity
• Mostly affects the upper molars and premolars but can also affect lower teeth
• The area of involvement can be initially localized but, as pain continues, may expand to involve other sites
• Pain may radiate or migrate to other sites
• Reduced, heightened, or altered sensation or complete numbness to pain
• Heat, cold and biting forces do not consistently worsen the pain
• Repeated dental therapies fail to resolve the pain, and can worsen the pain
• Psychological impact due to the persistent pain

How Is Trigeminal Neuropathic Pain Treated?

If trigeminal nerve involvement is suspected during oral surgery such as implant placement, the recommendation is to stop the procedure, prescribe potent anti-inflammatory agents and closely follow-up with the patient. If normal sensation does not return, micro-surgery may be indicated, preferably in the first six months after the injury.

Chronic and idiopathic cases of trigeminal neuropathic pain are managed with neuropathic medications, topical neuropathic pain medications applied to the affected areas, nerve blocks, cognitive behavioral therapy, and lifestyle changes. In severe recalcitrant cases, surgery may be recommended.