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The three types of percutaneous rhizotomy procedures that are currently used for the surgical management of trigeminal neuralgia pain include:

• Percutaneous Glycerol Rhizotomy - Once the surgeon has advanced and confirmed the correct position of the needle, the chemical glycerol is injected through the needle into the space surrounding the Gasserian ganglion and trigeminal nerve root resulting in mild injury to the nerve. Although most patients achieve early pain relief after undergoing this procedure, the pain may recur within a few years in up to 50% of cases.

• Percutaneous Balloon Compression Rhizotomy - In this procedure, usually performed under general anesthesia followed by an overnight stay in the hospital, the surgeon advances a large-caliber needle to the area of the Gasserian ganglion and confirms the correct positioning of the needle. A balloon-tip catheter ( a tube with a balloon at its tip that can be inflated and deflated after placement) is then advanced through the needle and the balloon is inflated. Mechanical compression of the inflated balloon causes physical damage to the Gasserian ganglion trigeminal nerve root.

• Percutaneous Radiofrequency Rhizotomy - In this procedure, usually performed under intravenous (IV) sedation, the surgeon advances a special radiofrequency electrode into the area of the Gasserian ganglion and verifies the correct positioning of the electrode. The electrode is then heated and the radiofrequency current that is generated produces thermal (heat) injury to the Gasserian ganglion and trigeminal nerve root/

Percutaneous rhizotomy surgical procedures for trigeminal neuralgia offer about an 80% chance for short-term pain relief (lasting at least one year) and about a 60% likelihood for longer-term pain relief (5 years or longer).

In general, the complication rate from percutanous rhizotomy surgical procedures for the treatment of TN is low. The most common complication is facial numbness. Although mild facial numbness is the goal of the procedure and is well tolerated by most patients, severe or extensive facial numbness can be quite bothersome. The most severe form of facial numbness is called anesthesia dolorosa. It involves constant, intense pain, burning and numbness in the region of the anesthesia. The risk of developing anesthesia dolorosa is higher with percutaneous radiofrequency rhizotomy (2% to 4% of cases) than with the other types of percutaneous rhizotomy procedures. Currently, there is no effective treatment for patients with anesthesia dolorosa. Other potential complications of percutaneous rhizotomy procedures include weakness of the masseter muscles causing a reduced chewing capacity and, in rare cases, injury to the cornea of the eye that can lead to keratitis (inflammation of the cornea) and blindness.

Stereotactic Radiosurgery (Gamma Knife)

This is a newer procedure that is being used for the treatment of trigeminal neuralgia. As is the case with the percutaneous rhizotomy procedures described above, stereotactic radiosurgery is also a destructive procedure designed to produce an injury to the trigeminal nerve in an effort to alleviate the pain. In this procedure, the injury to the trigeminal nerve root is accomplished using a gamma knife which delivers focused beams of cobalt radiation directly to the trigeminal nerve root without damaging the surrounding brain tissue or blood vessels. The "gamma knife" is actually not a knife at all but an instrument that uses focused beams of radiation to perform brain surgery; this type of surgery is also called stereotactic radiosurgery.