For trigeminal neuralgia, a careful escalation of remedies
Date: December 1, 2011
The main reason Michael Lim recommended a surgical procedure is because his patient was no longer finding pain relief from more modest therapies.
"This often happens in cases of trigeminal neuralgia," says the Johns Hopkins neurosurgeon.
As physicians know, TN stems from a compromise in the sheathing that protects the integrity of the fifth cranial nerve. That layer can be worn thin after years of friction from a pulsing artery adjacent to the nerve.
Trigeminal neuralgia most often afflicts women and typically presents in the fifth through seventh decades of life. But it can start earlier, says Lim, and the age of onset for TN can play a role in the application of therapy.
In TN’s early stages, standard analgesics have little effect in ameliorating the sometimes hair-trigger occurrences of intense pain. Some physicians succeed with traditional antidepressants like amitriptyline or with anticonvulsants like gabapentin or phenytoin. But Lim says he has also attained some of his best medical management using the antiseizure drug carbamazepine.
Yet the underlying mechanism that causes TN can adapt with time, eventually defeating the effects of medication. In such cases, Lim may progress to radiotherapy to ablate the arterial/neural juncture. The resulting scar tissue can mute TN’s stimulation.
Lim says radiotherapy succeeds more than 80 percent of the time, quickly relieving pain and allowing patients a rapid return to work. In some cases, he can achieve similar results by injecting a form of glycerin into the site.
The limit of these mid-range therapies is that they can cause zones of facial numbness, Lim explains, and the TN symptoms will usually recur within five years.
He has an answer for those cases, too.
Approximately 200 times every year, he and fellow neurosurgeon Benjamin Carson perform a microvascular decompression. In the three-hour surgical procedure, surgeons separate the artery from the trigeminal nerve and insert a small Teflon pledget in the new space.
Lim reports that most patients who undergo the procedure are discharged from the hospital after two days and return to work in less than six weeks. He says the procedure is 90 percent successful and that up to 80 percent of patients remain free of TN pain even 20 years later.
Hopkins’ relatively large patient number in this field ensures that specialists are aware of nuances in procedure and recovery.
“We offer the full set of TN procedures,” Lim says.
To refer a patient 410-955-6406.