Trigeminal neuralgia is a headache that affects quality of life and can disrupt socioeconomic life. Treatment options are medical treatment, interventional pain treatment, and surgery. Antiepileptics such as carbamazepine, oxcarbazepine, and lamotrigine are recommended in the first line of treatment(5). The first-line drug carbamazepine in particular has serious side effects such as aplastic anemia, hepatotoxicity, thrombocytopenia, leucopenia, and hyponatremia(6). In patients with systemic diseases and in the elderly population, these drugs may cause much more serious problems. Due to these side effects, many patients cannot tolerate medical treatment, and treatment doses are thus insufficient. Therefore, it seems more reliable to try minor interventional methods before medical treatment in trigeminal neuralgia during pregnancy because of side effects.
Alternative methods to medical treatment of trigeminal neuralgia are peripheral neurectomies, percutaneous radiofrequency rhizotomy (PRR), percutaneous glycerol rhizotomy (PGR), percutaneous balloon compression (PBC), stereotactic radiosurgery (gamma knife radiosurgery (GKRS), CyberKnife) and microvascular decompression (MVD). Percutaneous radiofrequency rhizotomy, percutaneous glycerol rhizotomy and percutaneous balloon compression may cause major complications such as nerve damage, anesthesia dolorosa, keratitis, aseptic meningitis, bacterial meningitis, and decreased corneal sensation.(7, 8)
Peripheral neurectomy as a minimal invasive surgical procedure is an old technique that can provide analgesia for about two years. Although it is usually performed under local anesthesia, general anesthesia may be needed(9). There is no majör complication but complications such as infection, sensorial loss and anesthesia dolorosa were reported (10).
Microvascular decompression surgery is the first-line surgical method in patients with neurovascular compression together with magnetic resonance imaging, and it has been shown to be painless for a long time, especially in men(11, 13). However, the effectiveness of MVD in trigeminal neuralgia caused by multiple sclerosis is much less. This procedure may also cause serious complications such as nerve damage, anesthesia dolorosa, cerebellar hematoma or infarction and even death(12, 14).
Percutaneous radiofrequency rhizotomy, which is more reliable than MVD, is performed with high temperature ablation by using radiofrequency needle, accompanied by imaging methods. Although its effectiveness is close to microvascular decompression surgery in the short term, it decreases after one year(15, 16). The high temperature (60–80 degrees Celsius) created in this procedure may cause nerve damage and anesthesia dolorosa. To avoid these serious complications, PRF was tested for percutaneous radiofrequency rhizotomy, but found to be ineffective(17). On the other hand, it gives better results than microvascular decompression surgery in multiple sclerosis-related trigeminal neuralgia(18).
Percutaneous glycerol rhizotomy and balloon decompression provide almost complete relief approximately in 75% of the patients, but these procedures may also cause complications such as nerve damage, aseptic meningitis, bacterial meningitis, and decreased corneal sensation(19, 20).
To avoid complications of the thermal lesion, PRF can be successfully applied in many neural structures such as dorsal root ganglion, sphenopalatine ganglion and suprascapular nerve(21–23).PRF seems to be a less destructive alternative technique which consists of regular intermittent RF waves and silent periods(21,24,25). It can be performed between 90 seconds and 240 seconds, but there is no consensus on the optimal lesion time(26). The temperature of the PRF site remains constant at 42 degrees Celsius, so it is known that there are no serious complications such as neural damage. The mechanism of action of the PRF is still not fully explained, but it may be related to the rapidly changing electric field regardless of temperature(27).
Interventional procedures on the peripheral branches of the trigeminal nerve usually do not cause serious neurological or vascular complications because they are not close to these important anatomical structures. The fact that PRF application is far from the neurological complications that may occur in conventional RF application makes the treatment completely safe(17,28). In our study none of the patients had serious complications such as anesthesia dolorosa, keratitis, aseptic meningitis, bacterial meningitis, decreased corneal sensation or nerve damage.
Results of this retrospective study showed that the duration of analgesia in various nerves that underwent PRF was different. For example, pain relief in mental nerve PRF procedure was longer than infraorbital and supraorbital nerve procedures. However, we concluded that the number of patients is insufficient for this assertion. In future studies it may be more accurate to evaluate this point of view with a larger number of patients.
This retrospective study showed that the PRF procedure in the peripheral branches of the trigeminal nerve may lead to pain relief for nearly one year. It has a lower risk of complications than other interventional methods. Another advantage is that it can be applied safely in many situations contraindicated for other procedures, pregnancy, coagulation defects and old age.
There ara some limitations of this study. First of all, the retrospective design of our study makes it difficult to evaluate the treatment response. In addition, increasing the number of participants and adding a control group can enable a better evaluation of the treatment effect.