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Clinical Briefings™: Clinical Reports from Penn Medicine

Friday, January 25, 2013

Comprehensive Surgical Options for Trigeminal Neuralgia

Neurosurgeons at Penn Medicine continue to pioneer and advance a comprehensive treatment program to address trigeminal neuralgia. The Penn Trigeminal Neuralgia program encompasses the spectrum of current and innovative treatment options, including endoscopic microvascular decompression surgery, Gamma Knife® radiosurgery and neuromodulation.

Vascular compression of the fifth cranial nerve as it enters the brainstem is among the most common causes of trigeminal neuralgia. Compression of the nerve results in intense unilateral facial pain affecting the forehead, cheek, jaw and teeth.

A leading surgical option, microvascular decompression (MVD) addresses the source of the neuralgia directly by inserting a barrier between the nerve and blood vessel. The barrier (a Teflon sponge) isolates the nerve from the dilation and pressure of the blood vessel, thereby relieving the symptoms of neuralgia.

MVD is performed through a small suboccipital opening on the affected side of the skull, and has the advantage of providing long-term relief of pain and preservation of facial sensation. Recently, the endoscope has been used during surgery to provide improved visualization of the offending pathology. This has resulted in greater surgical confidence and patient success.

Gamma Knife radiosurgery is an effective, minimally invasive approach to trigeminal neuralgia, and is used in patients for whom more invasive approaches are unsuitable. Gamma Knife concentrates approximately 200 individual beams of radiation on a single point to create a focused, surgical lesion within the nerve to block the transmission of pain signals. The procedure results in minimal damage to normal tissues.

Neuromodulation is an ideal approach for patients with atypical facial pain. Electrodes are placed through small (less than 1 cm) incisions in the skin to tunnel electrodes over the supraorbital (V1) and infraorbital (V2) branches of the trigeminal nerve. The procedure is first performed as a trial. If the stimulation provides pain relief, the electrodes are attached to a pulse generator placed subcutaneously in the infraclavicular space. Studies suggest that neuromodulation offers substantial relief for the majority of patients.


Case 1
Mrs. T, a 40-year-old woman, visited a neurologist for treatment of trigeminal neuralgia radiating into the right side of her face. Over a period of several years she was prescribed Tegretol (carbamazepine), Neurontin (gabapentin) and baclofen. These drugs helped initially. Over time, however, Mrs. T experienced breakthrough pain. She was then referred to Penn Neurosurgery, where she estimated her pain to be 10/10 during breakthrough episodes. After a discussion of her options, Mrs. T
agreed to microvascular decompression procedure.

The procedure: Following general anesthesia, a one-inch incision was made behind Mrs. T’s right ear and a 1 cm keyhole incision made in the dura mater (see “Minimally Invasive Endoscopic MVD Surgery,” back page). Endoscopic microsurgical exploration revealed that the superior cerebellar artery was compressing the nerve at the dorsal root of the right trigeminal nerve (Fig. 1). The artery was dissected away from the nerve and a Teflon sponge placed between the vessel and nerve to act as a barrier. The endoscope and instruments were then retracted and the small wound closed.

Results: Mrs. T went home on the second postoperative day. She was able to discontinue her medications within two weeks of surgery, and at her six-month follow-up reported a significant reduction in discomfort.

Case 2
Mr. Z, an 80-year-old man with a history of left-sided V2 trigeminal neuralgia, came to Penn Neurosurgery to explore options for treatment following an increasing intolerance to the side effects of medication, which included carbamazepine, neurontin, and trileptal. Because of his age, it was recommended that Mr. Z have Gamma Knife radiosurgery rather than an open procedure. 

The procedure: Mr. Z was fitted with a frame to stabilize his head during the procedure. A series of imaging scans was then performed to accurately pinpoint the root of the trigeminal nerve and develop dose planning (Fig. 2). During the procedure, approximately 200 beams converged at the target to deliver a single dose of gamma knife radiation (80 Gy). Mr. Z. was discharged home the same day.

Results: Mr. Z’s pain improved over the course of several weeks, during which time he noticed a gradual diminishment in the number and severity of triggers for his neuralgia. At his six-month follow-up visit, he reported that he was able to satisfactorily control his pain with occasional NSAID use. 

Gamma Knife® is a registered trademark of Elekta AB (publ) or it’s subsidiaries.


Case 3
Mrs. L, a 55-year-old woman, had a twelve-month history of burning pain radiating from her forehead. This pain was precipitated by a chickenpox outbreak. The skin vesicles had disappeared, but the pain had increased over time in both intensity and duration, and was constant when she was referred to Penn by an outside neurologist. Her treatments for pain included the antiepileptic drugs carbamazepine and gabapentin, both of which had provided transient relief, but to which her pain was now refractory.

The procedure: After a discussion of her options, Mrs. L chose to have a neuromodulation procedure. During her surgery, an electrode was implanted above her eyebrow and under the skin (Fig. 3).

Results: Mrs. L trialed the effects of the stimulation for several days before concluding that the “tingling” sensation was very soothing. She went on to permanent implantation with an implanted battery and was discharged on the same day as her surgical implant. At one year followup, she continued to have approximately 70% relief of the pain with use of the stimulator and was pleased with the results.





Faculty Team
Penn Neurosurgery is comprised of a skilled team of neurosurgeons, each of whom has a particular subspecialty focus. This permits the department to encompass the spectrum of surgically treated disorders of the nervous system. Given the enormous volume and intensity of exposure, patients benefit from that experience as well as the multidisciplinary approach to achieving the best possible outcomes.

Treating Trigeminal Neuralgia at Penn Medicine

John Y.K. Lee, MD
Director, Cranial Nerve Disorder Center
Medical Director, Penn Gamma Knife Center
Assistant Professor of Neurosurgery

Eric L. Zager, MD
Professor of Neurosurgery

Access
Penn Neurosurgery
Pennsylvania Hospital
Washington Square West Building
235 South 8th Street
Philadelphia, PA 19106

Hospital of the University of Pennsylvania
3 Silverstein
3400 Spruce Street
Philadelphia, PA 19104

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