The challenge for patients with facial pain is that diagnoses such as trigeminal neuralgia (TN), persistent idiopathic facial pain, type I/II TN are all clinical diagnoses. There are no blood tests, imaging studies, or genetic tests that can diagnose these conditions. Hence, these diagnoses are essentially descriptors of a patient’s pain and highlight the fact that we often do not know the cause of facial pain in patients.
In general, classical TN patients have episodic sharp, stabbing, or electric pain that is localized to the face whereas patients with what is commonly called atypical facial pain, but is correctly named persistent idiopathic facial pain, have pain that is NOT sharp/stabbing/electrical. Often patients with persistent idiopathic facial pain have symptoms such as: burning, aching, throbbing with or without associated numbness that is often constant. In addition, there are a group of patients who have a mixture of the classical TN and persistent idiopathic facial pain. Furthermore, pain in patients can evolve from classical TN to persistent idiopathic facial symptoms. As a result, we are battling an entity that clearly has multiple causes.
For patients with persistent idiopathic facial pain, the traditional TN procedures, such as microvascular decompression (MVD), rhizotomy, and stereotactic radiosurgery generally do not work. Sometimes these treatments accelerate the progression of a patient’s pain. In addition, there is a subset of patients who present with classical TN symptoms but then develop burning idiopathic pain after an ablative procedure such as a rhizotomy.
Hence, we know that the clinical symptoms are still not exact in determining true TN and other types of facial pain. Furthermore, the clinical symptoms cannot predict with 100% certainty that patients will respond to certain therapies. There is an obvious need to be able to better identify and classify a patient’s pain to be able to help choose and predict responses to therapies.
The strategy for patients suffering from persistent idiopathic facial pain should focus on two goals:
1. To find the cause of their pain.
2. To find relief for their pain.
Both goals can be achieved in parallel and in fact both journeys may follow different paths. In terms of the first goal of finding the cause of their pain, patients need to work closely with a neurologist to rule out known causes (such as inflammatory conditions, or tumors). However, we know that the cause may often be difficult to determine, which highlights the fact that more research is needed. Scientists are actively studying new pain pathways and receptors in the cell and anatomically in the brain.
For the second goal of pain relief, current therapies primarily focus on medications, blocks, and injections that are often partially or wholly ineffective and have significant side effects. In addition, newer modalities such as transmagnetic stimulation (TMS) and neuromodulation techniques are starting to gain traction, but the results are still preliminary. We are not where we want to be as a field with treatment options for patients with persistent idiopathic facial pain and it is common for patients to get minimal to no relief with current therapies. Therefore, new medications and new modalities are badly needed.
Conclusion: Persistent idiopathic facial pain is a challenging disease for patients and providers. Our current approaches are mainly medical, and these therapies are often accompanied by significant side effects and incomplete pain relief. Further research and novel therapies are needed for patients with this type of facial pain.
