NEW ORLEANS — Intraorbital frontal nerve resection appears effective for some patients with idiopathic trigeminal neuralgia where the ophthalmic division (V1) is involved, researchers say.
The procedure offers long-term relief in a condition where previous surgical and medical treatments have often only temporarily helped, said Susan Tucker, MD, an oculoplastic surgeon at Lahey Hospital and Medical Center in Peabody, Massachusetts.
"The results are excellent," she told Medscape Medical News. "If you have somebody with first-division trigeminal neuralgia, and it affects just this peripheral division of the trigeminal nerve, this is fantastic and should be the first procedure done for it."
However, the procedure fell short for patients with post-herpetic trigeminal neuralgia in the study that Tucker presented here at the American Society of Ophthalmic Plastic & Reconstructive Surgery Fall Scientific Symposium.
About 4 to 5 out of 100,000 people experience trigeminal neuralgia, and about 20% have involvement of the nerve's ophthalmic division. The patients feel a sensation similar to an electric shock.
The condition is generally caused by compression and areas of demyelination, with no sensory loss. Medical treatments such as carbamazepine are often given, but frequently the effects are modest or temporary, Tucker said.
Percutaneous procedures include glycerol injections, with a 70% recurrence of pain by 5 years; radiofrequency thermal rhizotomy, with a 40% recurrence in 5 years; and balloon microcompression, with a 20% recurrence in 5 years, said Tucker.
Gamma knife radiosurgery — in which gamma rays from radioactive cobalt pass through the skull into the intracisternal portion of the trigeminal nerve — has a 45% recurrence in 3 years, she said.
Microvascular decompression relieves the pain in about 70% of patients long-term, but complications include hearing loss, cerebrospinal fluid leakage, stroke, meningitis, extraocular leakage, motor dysfunction, anesthesia dolorosa, and death, said Tucker.
Postherpetic neuralgia differs. It affects 10%-15% of people with shingles, which works out to 58 people per 100,000. It causes steady burning pain and involves significant sensory loss. Treatments include antidepressants, anticonvulsants, and topical anesthetics.
"If you can excise a long segment intraoperatively of the frontal nerve and its branches, the hope was that that would lead to increased pain-free intervals," Tucker said.
For patients whose pain occurs on V1, frontal nerve resection offers some advantages, Tucker said. For example, it affords direct access to the supraorbital and supratrochlear nerves. The operating time is only 15-20 minutes. Bleeding is minimal. And there's no risk of corneal anesthesia because the nasociliary branch is not affected.
Although at first she performed the procedure under general anesthesia, Tucker now uses intravenous or even local anesthesia.
For the procedure, Tucker makes a small cut in the upper eyelid. "Through this skin crease incision, I go as far behind the eye as possible, and try to get to the main trunk of the frontal nerve and then cut out the largest segment possible," she said.
In her presentation at the conference, Tucker analyzed her records on eight patients who had experienced either V1 or combined V1 and V2 pain for at least 2 years, then had surgery from 2002 to 2008, with a mean follow-up of 12.8 years.
She found that 5 had no recurrence of pain in the V1 division. In one of these, pain recurred on the v2 division. The 5 without recurrence of pain included two who had not gotten relief from prior surgical procedures. The 3 patients whose V1 pain recurred were able to control it with medication.
The 3 patients with postherpetic pain all experienced recurrence of pain after this procedure, though the pain was less than before the surgery, Tucker said.
Tucker concluded by recommending the procedure as first-line treatment for isolated frontal nerve distribution idiopathic trigeminal neuralgia.
But she acknowledged that the procedure is restricted to a subset of patients with trigeminal neuralgia and didn't appear effective for postherpetic pain. Complications include permanent numbness and transient ptosis, she said.
Jacques Morcos, MD, a professor and co-chair of neurosurgery at the University of Miami, Florida, typically performs vascular decompression on patients with trigeminal neuralgia. He questioned whether resecting the frontal nerve could address the source of the pain. "What my skepticism would be is it's too far downstream in the nerve to have a physiologic mechanism to eliminate the pain," he said.
If the pain originates in the V1 division near the orbit, this procedure might help, but such pain would not normally be classified as trigeminal neuralgia, he said.
He added that the study was too small to be definitive. "It's going to take a lot more than a handful of patients and a very long-term follow up to convince me that this works," he said.
Tucker and Morcos have disclosed no relevant financial relationships.
American Society of Ophthalmic Plastic & Reconstructive Surgery (ASOPRS) 2021 Fall Scientific Symposium. Presented November 11, 2021.
Laird Harrison writes about science, health, and culture. His work has appeared in national magazines, in newspapers, on public radio, and on websites. He is at work on a novel about alternate realities in physics. Harrison teaches writing at the Writers Grotto. Visit him at lairdharrison.com or follow him on Twitter @LairdH
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Cite this: Trigeminal Neuralgia: Intraorbital Cuts HelpSome Patients - Medscape - Nov 12, 2021.
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