Trigeminal neuralgia is a condition affecting the trigeminal nerve, which carries sensation from receptors in the face to the brain. This nerve is a small, thick nerve cluster connecting to the brain, with multiple smaller, narrower nerve endings leading out to different regions of the face. This condition generally occurs when a blood vessel near the base of the thicker nerve cluster becomes abnormally swollen or displaced, which can put pressure on the trigeminal nerve and cause it to malfunction. This causes the facial receptors to register even mild sensation as extreme pain.
Because the pain is caused by swollen blood vessels, one of the methods by which it is treated is a surgical procedure known as microvascular decompression, in which the problematic blood vessel is surgically corrected to remove the pressure on the trigeminal nerve. Although an effective and proven method of treatment, there are some cases of trigeminal neuralgia in which this surgery will be ineffective, because the pressure on the nerve does not result from a swollen blood vessel.
Due to the location of the nerves and vessels in question, determining whether or not the patient’s condition was caused by a compressed nerve used to be difficult to determine, but a 2020 study has given doctors a set of distinct characteristics that can be used for a fast and correct diagnosis.
Trigeminal Neuralgia and Neuroanatomical Imaging
A neuroanatomical scan is a process that allows medical professionals to map out the position of a patient’s nerves before beginning treatment. An MRI (magnetic resonance imaging) scan of trigeminal neuralgia patients was used to compare the sizes and shapes of the nerves in question and determine concrete factors that could be used to predict whether neurovascular decompression will be helpful to that patient.
In a confirmation of some previous theoretical research on the subject, it was determined that those with larger nerves or cranial volumes tend not to respond to surgery. Two structures in particular, known as the contralateral trigeminal nerve and hippocampus, were identified as reliable predictors of non-response; patients in whom these structures exceeded a certain volume were non-responsive, making them useful indicators for medical professionals dealing with this condition.
Future Developments
Confirming the connection between neural structure and patient response is an important step toward creating a reliable means of determining what treatment is most advisable for the individual patient. By providing the medical professionals involved with an objective standard to determine the effectiveness of a treatment, this study has eliminated a significant amount of the subjective elements that can complicate attempts to treat chronic or recurring pain.
One possible application of this discovery outside of treating trigeminal neuralgia is as a basis for establishing the relationship between the body’s different nerve networks and other causes of chronic pain. It may be possible to create an empirical map of what nerve anatomy is needed for a given pain treatment to be effective, allowing for faster and more effective diagnosis of a patient’s condition.
References
- Trigeminal neuralgia
- Microvascular Decompression Surgery
- Hippocampal and trigeminal nerve volume predict outcome of surgical treatment for trigeminal neuralgia
- Size matters! The neuroanatomy of trigeminal neuralgia´s treatment response
- Predicting pain relief: Use of pre-surgical trigeminal nerve diffusion metrics in trigeminal neuralgia
- Trigeminal neuralgia – New classification and diagnostic grading for practice and research
