Article

Facial pain is a relatively common clinical condition with multiple aetiologies, often requiring the expertise of various medical specialists.

The sensory functions of the face are primarily managed by the trigeminal nerve, which has three branches responsible for transmitting pain sensations from the forehead, maxilla, and mandible. In addition to superficial sensations, the trigeminal nerve also conveys deep sensations from structures such as the sinuses, gums, tongue, and even the intracranial meninges. Due to the complex structure of cranial nerves, there are many potential causes of facial pain. Common conditions include herpes zoster outbreaks, postherpetic neuralgia, trigeminal neuralgia, dental pain, and temporomandibular joint disorders. Severe intracranial tumours or vascular diseases can also lead to facial pain. Diagnosis often requires a detailed medical history and clinical examination, alongside imaging studies, as it involves multiple specialties, including oral and maxillofacial surgery, dentistry, otolaryngology, and neurology.

Clinical Presentation of Trigeminal Neuralgia
Trigeminal neuralgia is a type of facial pain characterised by sudden, severe pain on one side of the face, described as sharp, stabbing, or electric shock-like. The pain typically lasts from a few seconds to 1-2 minutes and often occurs in areas such as the upper lip, nostrils, corners of the mouth, gums, and buccal mucosa. Triggers can include touching the face, eating, or brushing teeth. The recurrent nature of these pain episodes can severely impact the patient's quality of life and mental well-being.

Aetiology of Trigeminal Neuralgia
Primary trigeminal neuralgia is primarily caused by the compression of the trigeminal nerve root as it exits the brainstem, usually by abnormally positioned blood vessels, such as the cerebellar artery or vein. This compression can create indentations on the trigeminal nerve root, leading to localised thinning and damage of the nerve sheath, resulting in short-circuiting between nerve fibres and causing trigeminal neuralgia.

Diagnosis
The diagnosis of trigeminal neuralgia is based on typical neuralgic symptoms, the exclusion of secondary factors, and the use of imaging studies. Magnetic resonance imaging (MRI) can help rule out intracranial structural lesions and assess the degree of vascular compression on the nerve.

Pharmacological Treatment
Most cases of trigeminal neuralgia are primarily managed with medication. Commonly used drugs include Carbamazepine and Oxcarbazepine. During treatment, around 75% of patients experience a significant reduction in pain, although some may require long-term medication. Side effects can include dizziness, fatigue, and instability while walking. Additionally, some patients may develop tolerance or experience a decrease in efficacy over time. Before prescribing these medications, it is important to test for the HLA-B1502 gene to avoid severe allergic reactions.

Surgical Treatment
For severe trigeminal neuralgia that does not respond to medication, surgical intervention may be considered. Microvascular decompression surgery is a definitive treatment aimed at relieving nerve compression, potentially curing trigeminal neuralgia while preserving sensory function. The procedure involves a craniotomy behind the ear, requiring an incision of about 4-5 centimetres. Under a microscope, the blood vessels that are abnormally close to and compressing the trigeminal nerve root are carefully separated and moved aside. A Teflon cushion is then placed to maintain separation between the vessels and the nerve, alleviating the pressure. This surgery can lead to the disappearance of pain while preserving facial sensation, and the recurrence rate is relatively low. Indications and risks for surgical treatment should be assessed in detail based on the patient's overall health and imaging results.

Neurotomy Treatment
The trigeminal ganglion is the point where sensory signals converge and transmit to the brainstem. Radiofrequency heating can be used to reduce pain signal transmission. This treatment is performed under local anaesthesia, using a facial puncture to introduce a radiofrequency needle to the trigeminal ganglion located at the base of the skull. During heating, facial sensation is monitored. Radiofrequency ablation is suitable for patients whose pain is unresponsive to medication and who are unwilling to undergo vascular decompression surgery. Approximately 90% of patients experience significant pain relief, although some may develop facial numbness or experience pain recurrence afterwards. This treatment is highly safe and can be repeated as needed.

Radiotherapy
Stereotactic radiotherapy, commonly known as gamma knife treatment, focuses radiation on the nerve root to achieve pain relief. This method does not involve surgical wounds, bleeding, or infection-related complications. About 70% of patients can achieve significant pain relief through this treatment.

Trigeminal neuralgia is a condition that significantly impacts the quality of life of patients. There are multiple treatment options available, and doctors will consider the patient's specific condition and the pros and cons of each treatment method to develop an individualized treatment plan aimed at achieving the best possible outcomes.