These therapies are designed to ablate or selectively destroy specific fibers of the trigeminal nerve.
The procedures represent a collection of different strategies ranging from compression of the nerve with a balloon (balloon rhizotomy or balloon nerve compression), alcohol injection of the nerve (alcohol or glycerol rhizotomy), and radiofrequency destruction of the fibers (RF rhizotomy or RF ablation). These therapies can be helpful for atypical facial pain or trigeminal neuralgia caused by multiple sclerosis.
Each of these approaches has a variable degree of effectiveness, numbness and nerve dysfunction and recurrence rates associated with procedures. Ablative therapies may also result in anesthesia dolorosa when the nerve fibers are severely disrupted. This condition creates painful numbness similar to “phantom pain syndrome” that may be difficult to treat.
In more dire cases of facial pain, or when radiofrequency ablation has not been effective, balloon compression of the trigeminal nerve is an option. This procedure uses stereotactic techniques to insert a small balloon to where the trigeminal nerve branches. It is inflated briefly, causing compression of the nerve. This typically affects the pain fibers as they are more sensitive than the sensory fibers.
Similar to the other percutaneous procedures, balloon compression has variable success rate and when successful, its effects typically last about 6-12 months. Side effects include worsening pain, facial numbness, anesthesia dolorosa (numb face, but with pain) and vessel injury. These outpatient procedures are performed in the operating room or radiology suites with general anesthesia.
Glycerol rhizotomy
In rare cases of refractory facial pain, glycerol or alcohol rhizotomy of the trigeminal nerve may have some effect. This procedure uses stereotactic techniques to insert a thin needle into the trigeminal nerve. The nerve is then instilled with either glycerol or pure alcohol. Similar to the other percutaneous procedures, glycerol rhizotomy has variable success rate and when successful, its effects typically last about 6 months.
Side effects include worsening pain, facial numbness, anesthesia dolorosa (numb face, but with pain) and vessel injury. These outpatient procedures are performed in the operating room or the office with local anesthesia.
Radiofrequency ablation
The most common percutaneous procedure for trigeminal neuralgia and its variants is radiofrequency ablation. This technique uses stereotactic methods to selectively insert a fine needle into the trigeminal nerve, heating the nerve with radiofrequency energy. This can selectively affect the pain fibers while maintaining the normal sensory and motor fibers within the nerve.
This procedure can achieve pain relief relatively quickly, but it is not as effective as surgical decompression or radiosurgery. The effects are also less durable, lasting typically between 6-12 months. Repeat procedures, however, are possible and well tolerated. Side effects are low, but include worsening facial pain, facial numbness, anesthesia dolorosa (numb face, but worse pain), and vessel injury. These are primarily outpatient procedures.
