Vol. 17, #1

Trigeminal Neuralgia:
Case Report And Review Of Treatment Options
P. G. Parameswaran, MD

ABSTRACT
Background Trigeminal neuralgia is an extremely painful and difficult condition to treat. Adding acupuncture to complement medical treatment might help reduce the dosage of drugs and thereby the adverse effects.
Objective To describe the experience of using acupuncture in a patient with trigeminal neuralgia.
Design, Setting, and Patient A 47-year-old man presented with constant, severe pain in the right side of his face over the nasolabial groove for more than 11 months. The pain had been progressively worse and was usually precipitated by brushing his teeth, shaving, washing his face, eating, and talking. The patient's neurologist treated him with 150 mg/d of carbamazepine; when the pain improved, the dosage was reduced. However, the pain worsened in 2 months and he was prescribed 1500 mg of oxcarbazepine 3 times daily. It did not relieve the pain, which had become constant with the severity higher than 10 on a scale of 1-10.
Intervention The patient was treated with acupuncture using 30-gauge needles at GV 20, ST 2, LI 20, TE 23, LI 4, and HT 7.
Main Outcome Measure Relief of neuralgia.
Results The patient's pain level during the 1st day of treatment dropped from 7/10 to 0 at the end of a 20-minute treatment. On his 5th visit, he reported feeling much better, the pain appearing only once every hour instead of being constant. The patient continued to improve and could eat and speak without pain. Since local pressure was still triggering the pain, he was treated with electroacupuncture at 1.5 MHz. At the end of 10 treatments, he continued having some mild pain, from 3-5/10, triggered only by local pressure. The patient was free of pain for the next 3 months except for mild pain on local pressure over the infraorbital area. He discontinued taking oxcarbazepine. However, at the end of 3 months, the pain recurred and was as severe as before. He was again treated with the same acupuncture points as before. Once-weekly treatment for 7 weeks failed to elicit any improvement and the treatment was discontinued.
Conclusion This case report describes a patient who responded well initially to acupuncture but was not helped when the condition relapsed. Recommendations of various authors in the selection of acupuncture points for treatment are presented.
KEY WORDS
Trigeminal Nerve, Trigeminal Neuralgia, Tic Douloureux, Chronic Facial Pain, Acupuncture

INTRODUCTION
Trigeminal neuralgia, also known as tic douloureux, is a chronic and disabling facial pain affecting about 40,000 US persons every year. The International Association for the Study of Pain defines trigeminal neuralgia as "a sudden, usually unilateral, severe, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve."1 The pain usually lasts for a few seconds to a minute and can be like an electric shock. Between attacks, the patient is usually free of pain. The pain may sometimes come in paroxysms, the frequency being variable; it is usually associated with physical triggers. The presentation is not always typical and variations may not always be easy to diagnose.

CASE REPORT
A 47-year-old Asian Indian man presented with constant, severe pain in the right side of his face over the nasolabial groove for more than 11 months. The pain had been progressively worse and was usually precipitated by brushing his teeth, shaving, washing his face, eating, and talking. Cold water over his face made the pain worse as well as cold breeze hitting his face. The patient's neurologist treated him with 150 mg/d of carbamazepine; when the pain improved, the dosage was reduced. However, the pain worsened in 2 months and he was prescribed 1500 mg of oxcarbazepine 3 times daily. It did not relieve the pain, which had become constant with the severity higher than 10 on a scale of 1-10. The pain at times would radiate to the rest of his face. The only significant incident in his history was that he had a dental bridge 15 years earlier, at which time he had felt some pain in the same location on the face, but it had resolved spontaneously. He has had no further pain in the past 15 years. Computed tomography of the sinuses showed a tiny retention cyst in the maxillary sinus and a deviated nasal septum causing some compromise to drainage of the right inferior meatus. Magnetic resonance images of the brain were reported normal. Magnetic resonance angiography of the intracranial vessels without contrast did not reveal any abnormal vascular loops or aneurysmal formation.

Examination revealed an anxious healthy male in obvious pain. The pain was in the line of distribution of the maxillary division of the trigeminal nerve. The only positive finding was tenderness in the right nasolabial fold in the region of LI 20. There were no skin changes or signs of inflammation either externally or over the buccal mucosa of the right cheek; there was no evidence of infection in the gum or teeth.

METHODS
The patient was treated with acupuncture using 30-gauge needles, with the following points: GV 20, ST 2, LI 20, TE 23, LI 4, and HT 7.

GV 20 was selected for its sedative and harmonizing effect. ST 2, LI 20, and TE 23 were selected to stimulate the infraorbital, the zygomatico facial, and zygomaticotemporal nerves. LI 4 was chosen for its analgesic properties. HT 7 was used to calm and regulate the spirit, thereby reducing the patient's anxiety.

RESULTS
The patient's pain level during the 1st day of treatment dropped from 7/10 to 0 at the end of a 20-minute treatment. He was treated once a week, and on his 5th visit, he reported feeling much better, the pain appearing only once every hour instead of being constant. At his next visit, he reported feeling very improved and that he could speak without pain. He was told to continue his medication during the acupuncture treatment but nevertheless omitted 1 or 2 doses every day and completely quit the week after the 5th treatment.

The patient continued to improve with only an occasional pain on applying pressure over the area, but now he could eat and speak without pain. Since local pressure was still triggering the pain, he was treated with electroacupuncture at 1.5 MHz. He continued to improve and at the 8th visit, it was noted that the area of pain had shifted superiorly over the lateral nasal and adjacent infraorbital area. The pain was mild on local pressure. At the end of 10 treatments, he continued having some mild pain, from 3-5/10, triggered only by local pressure. He believed that he could live with that pain and thus, he discontinued treatment.

The patient was free of pain for the next 3 months except for mild pain on local pressure over the infraorbital area. He discontinued taking oxcarbazepine. However, at the end of 3 months, the pain recurred along the nasolabial fold and was as severe as before. He was again treated with acupuncture, selecting the same points again. He would have relief of pain during treatment but the relief would not last beyond that. Once-weekly treatment for 7 weeks failed to elicit any improvement and the treatment was discontinued. He again started taking oxcarbazepine and finding no relief, switched to carbamazepine with some relief.

DISCUSSION
Anatomy of the Trigeminal Nerve
The trigeminal nerve is the largest of the cranial nerves, providing sensory input to the skin of the face and anterior half of the head, teeth, oral and nasal cavities. It has limited motor component to the muscles of mastication. The nerve divides into 3 major divisions: the ophthalmic, the maxillary, and the mandibular nerves. The mandibular division is the largest of the 3, and its motor component supplies the muscle of mastication.2

Incidence
Trigeminal neuralgia is more common in women and is seen almost exclusively in persons older than 40 years and most often, between the ages of 50 and 69 years. Attacks are more common on the right side of the face.

Etiology
Trigeminal neuralgia is most often idiopathic in origin. It could be a symptom of central nervous system disease; other causes are:  secondary to compression of the sensory root adjacent to the pons by a tumor, an enlarged superior cerebellar or anterior inferior cerebellar arteries, or by pontine branches of the basilar artery or vein or arteriovenous malformations.2 Such compression can lead to demyelination of the nerve root.3 Uncommonly it could be a presentation of multiple sclerosis and should be suspected when trigeminal neuralgia occurs in a young person.4

Pathophysiology
The mechanism of pain production has been controversial. As per one theory, peripheral injury or disease of the trigeminal nerve increases afferent firing in the nerve. There may be associated failure of the central inhibitory mechanism as well. Pain is perceived when nociceptive neurons in a trigeminal nucleus involve thalamic relay neurons.4 Studies indicate that trigeminal neuralgia is usually caused by demyelination of trigeminal sensory fibers within either the nerve root or less commonly, the brainstem.5 The cause of pain is explained by the ignition hypothesis. According to the hypothesis, trigeminal neuralgia results from specific abnormalities of trigeminal afferent neurons in the trigeminal root or ganglion. Injury renders the axons hyperexcitable. The hyperexcitable afferents, in turn, give rise to pain paroxysms as a result of synchronized after-discharge activity.6

Natural History
Though spontaneous remission is common, over time, the disorder is progressive and the pain becomes more severe and more frequent, requiring higher dosage and more continuous use of medications.8
Diagnosis
Diagnosis of trigeminal neuralgia is based exclusively on history, symptoms, and normal neurological examination results. Trigeminal neuralgia is characterized by brief episodes of severe pain in the face. The pain usually lasts for a few seconds to a minute or 2. It is usually limited to one division of the trigeminal nerve and more often to the right side of the face. The mandibular and maxillary divisions of the trigeminal nerve are more often involved than the ophthalmic division. Eating, speaking, or touching specific sites in the face, such as occurs while shaving or brushing teeth, can act as a trigger. The patient is usually pain-free between episodes. The patient's face may contort with pain depending on its severity; hence, the name "tic douloureux."

Differential Diagnosis
Other causes of facial pain from local facial structures and pain from neuralgia have to be considered in the differential diagnosis. A syndrome similar to trigeminal neuralgia can be caused by acoustic neuroma, aneurysms, trigeminal neuromas, and meningiomas. These conditions should be considered, particularly if the patient is younger than 40 years and has pain predominantly in the forehead and eye (ophthalmic division of trigeminal nerve), when the pain is bilateral, or there is evidence of bilateral sensory loss or associated motor signs such as weak jaw, facial weakness, or swallowing difficulty.7

Diagnostic Studies
Diagnostic studies may be necessary when the condition occurs in a younger person or when the presentation is atypical. Magnetic resonance imaging (MRI) and 3-dimensional fast-in-flow with steady-state precession MRI may help to determine the presence of tumors or plaques of multiple sclerosis.1 It will also help to assess possible compression and deformation of the trigeminal nerve.

MRI neuroimaging using the technique called 3-D volume acquisition with contrast injection can detect an offending vascular loop causing compression on the nerve 80% of the time.8

Acupuncture Treatment
There are several reports of successful acupuncture treatment for large series of patients with trigeminal neuralgia, especially in the Chinese literature. However, there is a paucity of reports in the English literature.

Points for treatment are selected appropriate to the affected division of the trigeminal nerve.  In the case of the first division, GB 14, EX 5, and TE 5; for the second division, ST 2, ST 3, and LI 4; and for the third division, ST 6, ST 7, and ST 45.

Wong9 advocates selection of points to stimulate affected branches of the 3 divisions of the trigeminal nerve: ophthalmic division: stimulation to frontal nerve, supraorbital nerve and supratrochlear nerve - BL 1, BL 2, Yin Tang (GV 24.5); maxillary division: stimulation to infraorbital nerve, zygomaticotemporal nerve, and zygomaticofacial nerve - ST 3, LI 20, TE 23; mandibular division: stimulation to inferior alveolar nerve - ST 7, stimulation to mental nerve - CV 24; and stimulation to auriculotemporal nerve - Tai Yang, stimulation of gasserian ganglion: GB 3. This is always combined with ant anxiety acupuncture points HT 7 and Shen Men (auricular).9

Deadman et al mention ST 4, ST 7, SI 18, TE 17, and GB 3 for the treatment of trigeminal neuralgia.10 Silva11 reported complete relief of pain in 36 of 42 patients with trigeminal neuralgia treated with daily 20-Hz electroacupuncture.

In a report of long-term treatment of 177 patients with facial and neck pain including trigeminal neuralgia, Lundeberg et al12 found that acupuncture was most effective in pain associated with muscle tenderness. Gunn13 recommends treating Splenius capitis, and cervicis, sub occipital muscles, masseter, and levator labii superioris.

Liao et al14 claim from their experience that acupuncture will help about 70% of patients with trigeminal neuralgia. They recommend the following points for treatment: GV 20, PC 6, ST 36, KI 3, and LR 3. Additional points are added depending on the division of nerve that is involved. For those with involvement of ophthalmic division: Ex-HN 5, BL 2, GB 3, and GB 14. For those with involvement of maxillary division: ST 2, GB 1, ST 7, ST 18, and ST 3. For those with involvement of the mandibular division: ST 7, ST 6, ST 5, and GB 3. For those with temperomandibular dysfunction: Ex-HN 5, GB 3, ST 7, GB 2, and ST 6.

Jayasuriya15 selects local points depending on the affected division of the trigeminal nerve along with Ah Shi and distal points: GV 20, GB 14, BL 2, EX 2, LI 4, and ST 44; for the ophthalmic branch GV 20, ST 2, ST 3, ST 7, GV 26,  SI 18, LI 20, LI 4, and ST 44; for the maxillary branch GV 20, EX 5, ST 4, ST 5, ST 6, and LI 4. He recommends daily treatment and strong manipulation at LI 4 when acute pain is present.  Gentle manipulation of the needles over the face may also be carried out every 5-10 minutes. Treatment for as long as an hour may be required in resistant cases. Additional body point ST 43 may sometimes be useful. Embedded needles at the faciomandibular area in the ear may help control pain between treatments. If the pain is too severe on the affected side of the face the opposite side may be needled. Although relief of pain occurs within a few treatments in most cases, several months' treatment may be needed for complete recovery.15

SI 18 is considered a very useful and important point in the treatment of trigeminal neuralgia.16 Beppu et al17 treated 10 patients with trigeminal neuralgia, 5 of whom were restored to a pain-free state. They concluded that meridian acupuncture treatment is useful and can be one therapeutic approach in the management of trigeminal neuralgia.

Zhang and Duan18 treated patients with trigeminal neuralgia needling ST 36, LR 3, LI 14, and GB 20 with BL 2, ST 7, or CV 24 depending on the branch involved. They reported relief of pain for at least 3 months in 49% and reduction in episodes of pain in another 32% in an average of 12 sessions.

Zheng19 reported treating 8 patients using points on the affected side except LI 4 on the contra lateral side. For involvement of the ophthalmic branch, GB 14, TE 23, and LI 4 were used. For the maxillary division, ST 6, ST 7, SI 18, LI 20, and LI 4 were needled. For the mandibular division, ST 4, ST 6, ST 7, CV 24, and LI 4 were used. Of the 31 patients treated, 17 were cured without relapse for 6 months and 8 were markedly better.

Liu and Fang20 in a recent article proposed a different approach to selection of acupuncture points. Clinical experiments have shown needling at GB 20, GB 12, and BL 10 relaxes spasm of the vascular smooth muscles thereby improving the blood flow in the vertebral basilar artery. The combined use of GV 23 and EX-HN 3 resuscitates and tranquilizes the mind, dispelling wind, dredging the channels and relieving spasm and pain. They postulate that this therapy may turn the pathological state into a normal physiological state, bringing a quicker recovery for patients with facial spasm, trigeminal neuralgia, and stubborn facial paralysis.

After treating more than 700 patients with craniofacial neuralgias with electroacupuncture and laser irradiation, Costantini et al21 concluded that the best results were achieved with patients who chose acupuncture as the first therapeutic approach, while patients who underwent other previous medical and/or surgical treatment had a worse response.

Laser Therapy
Walker and associates22 have reported treating trigeminal neuralgia with low-power lasers.

Auricular Acupuncture
 The trigeminal nerve point in the ear is located along the peripheral edge of anterior and posterior lobe 116 F. The auricular points for treatment as per Oleson are: primary points: trigeminal nerve, face upper jaw, lower jaw, occiput, point zero, Shen Men. Supplemental points are Master oscillation, Master sensorial, Master cerebral, shoulder, brainstem, mouth, liver, and minor occipital nerve.23

Bloodletting Puncture With Cupping
Zhang24 has reported bloodletting puncture with cupping as an effective therapy for acute trigeminal neuralgia.

Homeopathy
Homeopathic treatment has proved effective in many patients whose condition has not responded to traditional treatments. The homeopathic approach to trigeminal neuralgia is holistic rather than isolated as a local disease. It is considered a constitutional disease and treated accordingly. The Homeopathy India Foundation claims a success rate of more than 70% at its center.25 The most common homeopathic remedies used are Aconite, Arsenicum album, Colocynth, Magnesia phos, Ranunculus bulbosus, and Spigelia.26

Medical Treatment
Medical treatment is often effective. Monotherapy with one anticonvulsant and, if the patient does not respond, a combination of more than one anticonvulsant, add-on therapy with newer drugs, and polytherapy with anticonvulsants, add-on drugs, and antidepressants/anxiolytics may be tried.27 Carbamazepine and baclofen have been found to be most effective, but it decreases with time. Newer medications such as pimozide, tizanidine hydrochloride, and topical capsaicin have shown some promise but none has been shown to be more effective than carbamazepine.3 Topical capsaicin cream showed improvement in 60% of patients using it in an open trial.28

Adverse effects of these drugs include nausea, vomiting, ataxia, vertigo, and transient leucopenia. A serious allergic manifestation can be persistent leucopenia and aplastic anemia. The patients taking these drugs will need to have periodic hemograms.

Nonsurgical Treatment
Nerve Block
Trigeminal nerve block with a local anesthetic using an indwelling catheter for pain control has been done preparatory to microvascular decompression.29

Surgical Treatment
Nondestructive Procedures
Microvascular decompression appears to be the only nondestructive procedure, which reliably relieves the symptoms of trigeminal neuralgia. This involves surgical exploration and coagulation or moving any compressing blood vessels. Pain might recur in 10%-15% of patients.8

Destructive Procedures
Patients whose pain does not respond to medical treatment may consider peripheral or central destructive procedures. Cryotherapy and alcohol injection act by blocking the peripheral branches of the trigeminal nerve. However, there is a high recurrence rate and repeated blocks are not recommended because of the risk of permanent facial anesthesia.3
Other peripheral destructive procedures include trigeminal branch avulsion or peripheral neurectomy, avulsion of the trigeminal nerve, and trigeminal tractotomy.23
Central procedures are performed by percutaneous or open approaches. Percutaneous destruction of the trigeminal nerve is performed by thermal rhizotomy, gamma knife radiation, glycerol injection, electro coagulation, or balloon compression.3
Open surgical treatments include microvascular decompression
and partial trigeminal rhizotomy.30

CONCLUSIONS
Trigeminal neuralgia is a chronic, progressive, painful, and disabling condition. It is difficult to treat because the condition may not respond to medical treatment or can become resistant, requiring toxic doses of drugs. There are adverse effects to the pharmacotherapy and serious risks associated with the nonsurgical and surgical destructive procedures. There are several large case reports in the Chinese literature of the effectiveness of acupuncture treatment without any adverse effects or complications. Only abstracts of these articles are available in MEDLINE and no English translations were available for this review.

The case presented herein is interesting because the patient responded well to the 1st course of acupuncture treatment, but not to the 2nd. His response to treatment the 1st time was gradual until he was completely pain-free while eating and speaking. However, I submit that acupuncture should be the first line of treatment for trigeminal neuralgia because of its lack of adverse effects and complications. Other modalities are available for those who are not helped by acupuncture. The local points chosen for treatment depend on the branch of the trigeminal nerve that is involved. Other additional points, local and distant, are chosen depending on their qualities and personal experience. Treatment may be required as often as daily and/or for a prolonged period because of the nature of the condition. Adding acupuncture to complement medical treatment might help reduce the dosage of drugs and thereby the adverse effects.

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AUTHOR'S INFORMATION
Dr P.G. Parameswaran is a General and Thoracic Surgeon in private practice in Houston, Texas. Dr Parameswaran also practices Medical Acupuncture, Hypnotherapy, Yogatherapy, and Energy Medicine.
P.G. Parameswaran, MD, MS, Mch*
Memorial Herman Southeast Professional Building
11914 Astoria Blvd, #555
Houston, TX 77089
Phone: 281-484-3149 • Fax: 281-484-8664
E-mail: pwaran@hotmail.com

*Correspondence and reprint requests

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