DREZ Lesioning for Phantom Pain
Date: September 1, 2007
Excruciating … agonizing … unbearable …. Patients conjure up all sorts of adjectives when describing phantom pain, or pain in a limb in which there is no sensation. But there are two they all use without fail. One is “crushing.” The other is “burning.”
“Imagine that a moving van is parked on your hand,” said one man whose hand had been paralyzed in a motorcycle accident. “Then someone comes along and sets the van on fire. That’s what phantom pain feels like.”
This patient, like many others in similar situations, wanted to have his hand amputated. “But that,” says neurosurgeon Allan Belzberg, “is the last thing you want to do. Amputating the limb isn’t going to help because the pain is coming from the level of the spinal cord.”
Phantom pain is associated with nerve injury, and in some patients the nerve has been avulsed, or torn from the spinal cord, because of an injury or disease. “When a nerve is pulled out of the spinal cord, the injury site, we think, develops epilepsy,” Belzberg explains. “So the spinal cord has an epileptic fit, so to speak, and rather than having a seizure, you feel pain that’s coming from the injured area in the spinal cord.”
Belzberg, who directs the Peripheral Nerve Center, treats phantom pain with dorsal root entry zone (DREZ) lesioning. Candidates are first evaluated with MRI, CT scan or myelogram for distortions of the spinal nerve roots. “What I’m looking for are little, fluid-filled cavities in each of the holes where the nerves exit the spine. A fluid cyst tells me there’s an avulsion injury.”
In the OR, Belzberg exposes the spinal cord and pinpoints the DREZ area where the nerves have been yanked out. Then, with the utmost precision, he makes a series of radiofrequency burns with an electrode. “Under the microscope we seat this electrode about 2 to 3 millimeters in a very specific area in the spinal cord. We do approximately 80 to 110 radiofrequency burns along the area we need to cover.”
Belzberg reports an 80 to 90 percent success rate with DREZ lesioning. “Over a period of one to three years following the procedure, however, some of the pain comes back because the physiology of the spinal cord adjusts,” he says. “But patients are very quick to tell us that managing even as much as 30 percent of the pain they had before is just nothing.”
Postoperatively, patients typically report immediate and complete resolution of neuropathic pain. “I’ve seen patients in the recovery room, crying with relief because they no longer have the phantom pain,” says Belzberg.
“When you repair a nerve and give someone back some function, you feel awfully good. But patients with phantom pain are often suicidal. Their lives have been absolutely destroyed. So this is one of the most, if not the most, dramatic operations I do in terms of impact on someone’s life.”
To refer a patient: 410-95-5810.