Percutaneous Procedures For Trigeminal Neuralgia

Overview

Trigeminal neuralgia (TN) is a debilitating condition characterised by sudden severe attacks of pain in the head and face (specifically the trigeminal nerve area). The pain is usually short-lived, lasting from a few seconds to a couple of minutes, but it can occur several times a day.¹ Whilst the first line of treatment for the condition usually involves medication, percutaneous procedures (involving a needle puncture of the skin), can be a promising alternative for patients who are unable to undergo surgery.

What is trigeminal neuralgia?

The trigeminal nerve is the fifth and largest of all the cranial nerves, providing sensation to the face and neck. Trigeminal neuralgia pain occurs when there is pressure exerted on the trigeminal nerve. This most commonly occurs due to compression of the nerve by a blood vessel.² However, in rare cases it can be caused by more serious conditions, such as a tumour or multiple sclerosis.¹

Trigeminal neuralgia (TN) is considered to be one of the worst pains a person can experience.² It is characterised by sudden, severe, stabbing pain in the face and head. The pain is usually short-lived, lasting only seconds to a couple of minutes, but it can occur repeatedly and several times a day. These neuralgia attacks can be triggered by touching the face, brushing teeth, or sometimes even talking and eating. Suffering from severe trigeminal neuralgia often poses a huge impact on quality of life and mental health.² 

What is the treatment for trigeminal neuralgia?

The first line of treatment for TN is medication, the most commonly prescribed medications being anticonvulsants such as carbamazepine.3 These aim to reduce the pain by slowing down electrical impulses within the nerves. When medication is not sufficient to control the symptoms of TN, there are surgical options available; the most common of these is microvascular decompression.4 Microvascular decompression aims to relieve the pressure on the trigeminal nerve by removing a small piece of skull. It is generally considered an effective treatment for TN, with a high chance of long-lasting effects.4 Nevertheless, it is very invasive and carries the risk of some severe side effects, such as facial numbness, stroke and hearing loss.⁵ There are also some populations, such as the elderly and those with comorbidities, where surgery is not an option.³ Because of this, percutaneous procedures are another viable treatment option. 

What are percutaneous procedures?

Percutaneous procedures involve inserting a needle through the cheek and into the trigeminal nerve whilst the patient is under heavy sedation. This procedure aims to reduce the pain signals carried along the nerve by injuring or damaging the nerve itself. There are 3 main types of percutaneous procedures:⁶

• Glycerol rhizotomy – this involves a glycerol injection into the surrounding area of the trigeminal nerve
• Percutaneous radiofrequency thermocoagulation – where a needle is used to apply heat directly to the trigeminal nerve
• Percutaneous balloon compression – where a tiny balloon is passed along a thin tube that has been inserted through the cheek. The balloon is then inflated around the nerve to squeeze it and damage the nerve. The balloon is then removed 

Indications for percutaneous procedures

Percutaneous procedures are often considered as a treatment for TN in older patients and for those in which surgery is not an option, such as patients with other health conditions. It may also be considered for those who wish to avoid the potential side effects of surgery, or in those who experience the symptoms of TN but show no evidence of actual nerve compression.³ 

Types of percutaneous procedures

Glycerol rhizotomy 

This procedure involves a glycerol injection administered under sedation where the trigeminal nerve exits the skull. The glycerol damages the large nerve fibres and slows down pain transmission.³ Before the procedure, a computer tomography (CT) brain scan and x-ray are performed to ensure the nerve can be located easily. The procedure is then performed whilst the patient is sedated and local anaesthetic is also administered to the cheek. Whilst the patient is under sedation, an incision is made in the cheek and a navigation probe is used to locate the nerve. Once the position is confirmed, the patient is sat up and the glycerol is injected into the nerve. People who have undergone the procedure are usually discharged on the same day as the procedure is performed. 

Evidence on the effectiveness of glycerol is mixed, but it seems to suggest a high initial success rate, with over 90% of people experiencing pain relief.^7,8 For some people, this pain relief can be temporary, although 50% of cases show improvement even after 3 years.⁷ Side effects include a small risk of bleeding and numbness in the face, which can sometimes be permanent.⁵ 

Percutaneous radiofrequency thermocoagulation (PRF)

PRF involves the controlled thermal ablation (destruction) of nerve fibres in the trigeminal ganglion or nerve root. The procedure is carried out under CT guidance to ensure the nerve can be accurately located. Pain medications and sedation are given to the patient, but they remain awake. A catheter is used to deliver stimulation to the nerve, ensuring the correct area is identified. Bursts of radiofrequency thermocoagulation are then administered to destroy the nerve fibres, thereby relieving the pain. 

PRF shows high effectiveness in the months following the procedure, with 90% of people reporting being pain-free at 6 months.⁹ However, there are indications that its effectiveness appears to decrease over time.^9,10 Complications following the procedure can include sensory loss over the area of the trigeminal nerve, weakness of the masseter (a muscle involved in the act of chewing food), and some painful sensations.¹⁰ 

Balloon compression 

Percutaneous balloon compression (PBC) involves inflating a tiny balloon to compress the trigeminal nerve ganglion. Under sedation, a needle is positioned into the skull via the foramen ovale. A catheter is then inserted, while neuroimaging techniques are used to deliver the balloon. The balloon is inflated, compressing the ganglion for up to 3 minutes; this damages the larger pain-carrying nerve fibres of the trigeminal nerve, providing long-lasting pain relief.¹¹ 

Evidence suggests the procedure results in immediate pain relief in 80-90% of cases, with recurrence rates of about 25% over a 10-year period.¹¹ PBC has many advantages, including a discomfort-free postoperative period, null mortality, and other minimal complications.^11,12 

Are there any other surgical options?

Recently, a newer procedure, called gamma knife surgery, has been developed for trigeminal neuralgia. This involves delivering controlled beams of radiation to the nerve, damaging the trigeminal nerve fibres.¹³ This procedure is less invasive than microvascular decompression or percutaneous procedures, and it requires little to no anaesthesia so it can be delivered on an outpatient basis. Reports suggest a reduction in pain in over 80% of patients, but the response is usually slower than for other treatments.¹³ 

Comparative effectiveness of percutaneous procedures in the treatment of TN 

When comparing the effectiveness of the procedures, one has to consider short and long-term pain relief, in conjunction with any complications and pain recurrence. Overall, microvascular decompression is shown to be the best surgical option for trigeminal neuralgia.¹⁴ However, for patients in which surgery is not an option, such as the elderly or those with multiple comorbidities, percutaneous procedures appear to be an effective alternative. 

Overall, percutaneous procedures have a high success rate of relieving pain in the short term, with few complications. Their effectiveness diminishes slightly over the longer term, yet success rates still remain high. 

FAQs

What surgery can be done for trigeminal neuralgia? 

Surgery can be considered an option for TN if medication has not been successful. Microvascular decompression has been shown to be the best surgical option for the condition. However, in cases where surgery is not advised, percutaneous procedures have also been shown to be an effective alternative. Percutaneous procedures involve inserting a needle through the cheek to the trigeminal nerve and using various techniques to damage the nerve reducing pain transmission. 

What is the newest surgery for trigeminal neuralgia?

Gamma Knife surgery is a new procedure for TN. It involves delivering controlled beams of radiation to the nerve in order to damage the nerve fibres.13 This procedure is less invasive than microvascular decompression or percutaneous procedures and requires little or no anaesthesia, meaning it can be delivered on an outpatient basis. Reports suggest a reduction in pain in over 80% of patients, but the response is usually slower than for other treatments.¹³ 

Summary

Trigeminal neuralgia is a painful and debilitating condition involving sudden severe attacks of pain in the head and face. The first-line treatment for trigeminal neuralgia involves medication that can be prescribed by your GP. If medication is unsuccessful, surgery is an option. Microvascular decompression has be shown to be the best surgical option for trigeminal neuralgia; however, percutaneous procedures are highly effective and have minimal side effects, making them a viable alternative for those who cannot undergo surgery, such as the elderly or those with comorbidities.