Atypical facial pain
"[6] However, the term AFP continues to be used by the World Health Organization's 10th revision of the International Statistical Classification of Diseases and Related Health Problems and remains in general use by clinicians to refer to chronic facial pain that does not meet any diagnostic criteria and does not respond to most treatments.
[7] The main features of AFP are: no objective signs, negative results with all investigations/ tests, no obvious explanation for the cause of the pain, and a poor response to attempted treatments.
[8] AFP has been described variably as a medically unexplained symptom, a diagnosis of exclusion, a psychogenic cause of pain (e.g. a manifestation of somatoform disorder), and as a neuropathy.
[7] As with AFP, there is a similar lack of standardization of terms and no consensus regarding a globally accepted definition surrounding AO.
[8] Research in individuals with AFP showed that there is increased cerebral activity (demonstrated during positron emission tomography), possibly suggesting that there is an overactive alerting mechanism to peripheral stimuli.
[14] Nowhere in the body is referred pain more well illustrated than in the face, and this is due to the richly and complexly innervated nature of the head and neck.
Osteonecrosis of the jaws refers to the death of bone marrow in the maxilla or the mandible due to inadequate blood supply.
The term NICO is used to describe pain caused by ischemic osteonecrosis of the jaws, where degenerative extracellular cystic spaces (cavitations inside the bone) are said to develop as a result of ischemia and infarctions in the bone marrow, possibly in relation to other factors such as a hereditary predisposition for thrombus formation within blood vessels, chronic low-grade dental infections and the use of vasoconstrictors in local anesthetics during dental procedures.
This proposed phenomenon has been postulated to be the cause of pain in some patients with AFP or trigeminal neuralgia, but this is controversial.
[9] Proponents of NICO recommend decortication (surgical removal of a section of the cortical plate, originally described as a treatment for osteomyelitis of the jaws) and curettage of the necrotic bone from the cavitation, and in some reported cases, this has relieved the chronic pain.
Because of the lack of clear etiological data, a NICO diagnosis should be considered only as a last resort when all possible local odontogenic causes for facial pain have been eliminated.
If a NICO lesion is suspected in relation to an endodontically treated tooth, if possible, periradicular surgery and curettage should be attempted, not extraction.
In addition, the practice of recommending the extraction of endodontically treated teeth for the prevention of NICO, or any other disease, is unethical and should be reported immediately to the appropriate state board of dentistry.
[8] Sometimes stressful life events appear to precede the onset of AFP, such as bereavement or illness in a family member.
It is argued whether this is a sole or contributing cause of AFP, or the emotional consequences of suffering with chronic, unrelieved pain.
[12] AFP and AO can be difficult to diagnose,[10] and are often misdiagnosed with resultant inappropriate attempts of treatment, e.g. root canal therapy which may at best have only a temporary benefit, or at worst lead to an increase in the pain.
[21] Another cited reason for discontinuing use of the term AFP is that some cases appear to follow surgeries or injuries involving the face, teeth and gums, possibly suggesting infectious or traumatic etiologies.
[22] Despite the controversy surrounding the use of the term, it has a long history, and it is still in common use by clinicians to refer to chronic facial pain that does not meet any diagnostic criteria and does not respond to most treatments.
[23] They theorized that this type was a progression of untreated classic trigeminal neuralgia, and represented worsening neural injury.
There were seven proposed sub-types of trigeminal neuralgia (TN) in this classification (see table), and the final category was reserved for facial pain caused by somatoform disorder.
However, a normal Radiograph, CT, and MRI may help to exclude other pathology such as arterio-veinous malformation, tumor, temporomandibular joint disorder, or MS. Psychosocial interventions for AFP include cognitive behavioral therapy and biofeedback.
A systematic review reported that there was weak evidence to support the use of these treatments to improve long-term outcomes in chronic orofacial pain,[1] however these results were based primarily upon temporomandibular joint dysfunction and burning mouth syndrome rather than ATP and AO.
Surgery may give a temporary remission from pain, but rarely is there a long term cure achieved via these measures.
In this study, the individuals had been subjected to a wide variety of different treatments, from surgery, antidepressants, analgesics and physical therapies.
