Trigeminal neuralgia refers to recurrent severe pain within the distribution and branching region of the trigeminal nerve.
The trigeminal nerve arises from the base of the middle part of the pons. It contains both sensory and motor nerve fibers, with sensory fibers constituting the majority. It gives off three major branches from the trigeminal (semilunar) ganglion.
Ophthalmic nerve branch: enters the orbit via the superior orbital fissure, distributes to the eyeball and lacrimal gland, and its terminal branch exits the orbit to supply the skin of the forehead.
Maxillary nerve branch: Exits the cranial cavity through the foramen rotundum, distributing to the maxilla and nasal cavity. The terminal branch of the main trunk emerges from the infraorbital foramen, supplying the skin of the face below the palpebral fissure and above the oral fissure.
Mandibular branch of the trigeminal nerve: It exits the skull through the foramen ovale into the infratemporal fossa. The motor fibers of the trigeminal nerve join the third division, innervating the masticatory muscles. The sensory fibers of the third division are distributed to the mandible, tongue, and auriculotemporal region.
Trigeminal neuralgia is generally classified into two types: primary and secondary.
1. Primary
That is, trigeminal neuralgia of unknown etiology. Some scholars believe it may be a traumatic factor.
Factors cause demyelinating changes in the sensory root and adjacent motor branch of the trigeminal ganglion. Demyelinated axons develop short circuits between adjacent fibers, whereby mild tactile stimuli can be transmitted into the central nervous system via these short circuits, and central efferent impulses can also become afferent impulses through them. When such impulses accumulate to a certain threshold, they excite neurons within the trigeminal ganglion, triggering pain. In some cases of primary trigeminal neuralgia, underlying causes can be identified, such as arteriosclerosis or arterial ectopia in the vessels supplying the nerve, thickened meninges, or a narrowed bony foramen due to periostitis that compresses the nerve root or ganglion. Clinically, trigeminal neuralgia primarily refers to primary trigeminal neuralgia.
II. Secondary Trigeminal Neuralgia
Trigeminal neuralgia with a clear etiology refers to pain symptoms caused by pathological changes in the trigeminal nerve itself or in adjacent tissues that affect, damage, or compress the trigeminal nerve. This includes conditions such as tumors, inflammation, or injury in the ear, nose, teeth, or other areas within the trigeminal nerve distribution. In addition to pain, such conditions present with neurological signs and localized symptoms.
【Key Diagnostic Points】
1. Primary (as in primary disease/pattern, not specific to TCM standard terminology)
This condition most commonly occurs in middle-aged and older adults, with roughly equal incidence in males and females. The pain typically strikes suddenly without warning and is characterized by distinct trigger points (i.e., mild stimulation of certain specific areas can immediately provoke pain). The pain is usually unilateral, most frequently involving the second and third divisions of the trigeminal nerve; simultaneous involvement of all three divisions is rare. The pain is severe—described as lightning-like, knife-cut, or drilling—and brief, typically lasting from a few seconds to one to two minutes. It occurs in recurrent episodes and may be accompanied by ipsilateral facial reflex twitching, flushing, conjunctival injection, lacrimation, and salivation.
II. Secondary
The clinical manifestations are similar to those of the primary condition but are persistent in nature. Once the secondary lesion is resolved, the associated pain also subsides accordingly. Due to its relationship with the secondary lesion, there may be accompanying signs of adjacent cranial nerve involvement, such as diminished facial sensation, decreased corneal reflex, hearing loss, and abducens nerve palsy. Symptoms such as increased intracranial pressure, epistaxis, and cervical lymphadenopathy may also be present.
**Examination:** Typical trigeminal neuralgia, not difficult to diagnose, is characterized by severe, brief, lightning-like pain within the distribution area of the trigeminal nerve. For secondary trigeminal neuralgia, the underlying cause should be identified through its clinical manifestations and auxiliary diagnostic findings.
Treatment
I. Acupoints and Acupuncture Techniques
1. LI4 (Hegu) (affected side): Located on the dorsum of the hand, between the 1st and 2nd metacarpal bones, near the midpoint of the 2nd metacarpal bone. Using a 30-gauge, 2-cun filiform needle, perform routine local disinfection and insert approximately 1.8 cun toward SI3 (Houxi). Needle sensation: local distension and pain.
2. ST2 (Sibai) (affected side): Located in the depression below the lower eyelid, directly below the pupil when looking straight ahead, corresponding to the infraorbital foramen of the maxilla. Using a 30-gauge, 1.5-cun filiform needle, perform routine local disinfection and insert approximately 1.2 cun into the infraorbital foramen. Needling sensation: local distension and pain.
3. **Taiyang (EX-HN5) (affected side)**: Located in the temporal region, in the depression one finger-breadth posterior to the midpoint between the lateral end of the eyebrow and the outer canthus. Use a 30-gauge, 2.5-cun filiform needle. After routine local disinfection, insert toward the angle of the mandible, passing behind the zygomatic arch, to a depth of approximately 2.2 cun. **Sensation**: Local distention and pain.
4. ST7 (Xiaguan) (affected side): Located on the face, anterior to the ear, in the depression formed by the zygomatic arch and the mandibular notch. After routine disinfection of the local area, insert a 28-gauge, 2-cun filiform needle perpendicularly to a depth of approximately 1.8 cun. Sensation: local distension and pain.
II. Methods
Select the affected side. The patient is seated. Each session, treat the facial pain points or trigger point area, and select 2 additional acupoints to combine with the above-mentioned acupoints. Insert the needles using the same needling technique as described above, retain for 40 minutes, and remove without twirling. Treatment is given once daily, with 10 sessions constituting one course. If effective, rest for 5 days before resuming needling; if ineffective, switch to an alternative method.
Appendix 1: Needle Retention at Pain Points
Prepare 1-2 sterile intradermal needles. Locate 1-2 tender points or trigger points within the trigeminal nerve distribution area. Perform routine local disinfection. Insert the needle subcutaneously into the center of the tender/trigger point. Use an alcohol cotton ball of the same diameter as the outer ring of the needle handle to protect the needle hole, and secure it externally with adhesive tape. Retain the needle for 2–3 days before removal. If the treatment proves effective, allow one day of rest before repeating the retention needling. Discontinue when the condition resolves.
Appendix 2: Block Therapy
I. Supraorbital Nerve Block
Indicated for first branch trigeminal neuralgia (V1), where pain occurs on one side of the orbital and frontal region and radiates to the vertex on the same side.
Method: Use a 2 mL sterile syringe fitted with a sterilized 4-gauge skin test needle. Draw 20 mg (1 mL) of procaine into the syringe. The patient may sit or lie supine. Locate the supraorbital notch (or foramen) at the midpoint of the supraorbital rim, slightly medial. Perform routine local disinfection. Insert the needle perpendicularly until it contacts the bone of the supraorbital rim, then search nearby for paresthesia. If the needle enters the foramen, advance 1.2–1.5 cm. Aspirate to ensure no blood return, then slowly inject the medication. After withdrawing the needle, apply pressure with a cotton ball to prevent bleeding. Following injection, a warming sensation may be felt over the ipsilateral forehead extending approximately 20 mm above the hairline; this is due to vasodilation and usually resolves within about one hour. Perform the procedure every other day. If no significant effect is observed after three sessions, switch to an alternative method.
**Infraorbital Nerve Block** (closed block of the infraorbital nerve)
Indicated for trigeminal neuralgia of the second branch, where pain occurs unilaterally in the lower eyelid, beside the nose, upper lip, or in the region of the upper incisors and canines.
**Method:** Use one 2 mL sterile syringe fitted with a sterile 6-gauge intramuscular needle. Draw up 20 mg (1 mL) of procaine and 1 mL of vitamin (micrograms) for use. The patient may be seated in a reclining position or lie supine. Locate the infraorbital foramen depression on the affected side, approximately 1 cm below the infraorbital margin and next to the nasal ala. Perform routine local disinfection. Insert the needle subcutaneously, then advance slowly and tentatively in an upward-posterior and upward-lateral oblique direction. A distinct loss of resistance indicates the needle tip has entered the infraorbital foramen; at this point some patients may experience radiating pain. Continue to advance the needle along the infraorbital canal at a 40–45° angle, slowly inserting about 8 mm in a posterior-superior and lateral-superior direction. Aspirate to confirm no blood return, then inject the medication. Upon withdrawal, apply pressure to prevent bleeding. Administer every other day; 6 treatments constitute one course. Discontinue if no effect is observed.
3. Posterior Superior Alveolar Nerve Block
Indicated for pain of the second branch of the trigeminal nerve, with the trigger point and pain area limited to the upper molars and their lateral mucosa.
**Method:** Prepare a 2 ml sterile syringe fitted with a sterile 5-gauge dental needle. Draw up 20 mg (1 ml) of Procaine and 1 ml of vitamin solution (e.g., Vitamin B12, as per clinical usage). The patient should be seated in a semi-reclined position with the head slightly tilted back and the mouth half-open. Use a mouth mirror to retract the buccal lip on the affected side. Wipe the saliva from the gingival area of the second molar with a sterile dry cotton ball. Then, [inject] near the mesial side of the second molar.
Insert at the buccal groove at the root, slowly insert at a 45-degree angle directed posteriorly, superiorly, and slightly medially, following the bone surface deeply 2–2.5 cm to reach the maxillary ganglion. After confirming no blood return on aspiration, inject the medication. Upon needle removal, apply pressure to the needle hole with a sterile dry cotton ball to prevent bleeding. Administer once every 3 days; discontinue if no effect after 3 treatments.
4. Superior Alveolar Nerve Block
Suitable for pain in the third branch of the trigeminal nerve (V3), with the trigger point and pain area located at the lower molars and their adjacent mucosa.
**Method:** Prepare a sterile 2 mL syringe fitted with a 5-gauge dental needle. Aspirate 20 mg (1 mL) of procaine and 1 mL of vitamin (unspecified, 1 mL) for use. The patient is seated in a reclining position with the head tilted backward and the mouth opened wide. Using a mouth mirror, retract the buccal lip on the affected side. The puncture point is located slightly above the tip of the buccal fat pad, lateral to the pterygomandibular fold on the buccal side. Dry the local saliva with a sterile dry cotton ball. Insert the needle diagonally from the position of the second premolar, parallel to the mandibular plane, and advance slowly through the pterygomandibular space. If referred pain to the chin area occurs, inject the medication slowly. Upon withdrawal, apply pressure with a sterile dry cotton ball to prevent bleeding. Administer once daily; discontinue if no effect after 6 treatments.
5. Mental Nerve Block
Indicated for pain of the third branch of the trigeminal nerve (V3), where the trigger points and painful area are located in the chin, lower lip, and adjacent mucosa.
**Method**: Use a 2 mL sterile syringe fitted with a 6-gauge intramuscular injection needle. Draw up Procaine 20 mg (1 mL) and Vitamin [name omitted] (1 mL) for use. The patient sits in a reclining position with the head turned to the unaffected side. The injection point is located at the lower border of the mandible, approximately at the midpoint of the upper and lower margins, below the second molar or between the first and second molars. After routine sterilization of the local area, insert the needle at a 45-degree angle from the posterosuperior direction toward the anteroinferior direction, advancing until it contacts the bone surface. In most cases, the needle can enter the mental foramen, and a paresthesia sensation will be elicited. If unsuccessful, withdraw the needle by 1–2 mm and gently move it along the adjacent bone surface until it enters the mental foramen. After confirming no blood return upon aspiration, slowly inject the medication. The procedure is performed every other day, and it should be discontinued if no effect is observed after six sessions.
VI. Trigeminal Ganglion Block
The procedure is primarily indicated when peripheral branch blockade has failed, or when pain originates from the second and third branches (maxillary and mandibular divisions). Care must be taken to avoid paralyzing the first branch (ophthalmic division), as this may result in neuroparalytic keratitis and subsequent blindness. Two approaches exist: the anterior approach and the lateral approach. In clinical practice, the anterior approach is more commonly used. The method is as follows:
Method: Prepare two sterile 2 mL syringes. One syringe contains procaine 20 mg (1 mL), and the other contains 0.6 mL of 98% absolute alcohol (reserved). The patient is positioned in the lateral decubitus position with the affected side facing upward. Locate the puncture point 2–4 cm lateral and inferior to the ala of the nose along the horizontal line. After routine local disinfection, use a sterile No. 6 closed needle (10 cm length). First, insert the needle subcutaneously at the identified point, then advance it toward the coronal plane of the ipsilateral pupil and above the ipsilateral external auditory meatus. Alternatively, a trigeminal ganglion localization ruler may be used to guide the puncture. The depth of insertion is approximately 6.8 cm. When the needle reaches the trigeminal ganglion (Gasserian ganglion), the patient will experience a radiating pain on the affected side. After confirming no blood or cerebrospinal fluid upon aspiration, inject 0.3 mL (6 mg) of procaine. If sensory loss occurs in the second and third division areas on the same side, replace the procaine with 0.5 mL of absolute alcohol. If the first division (ophthalmic branch) becomes numb after the procaine injection, postpone the alcohol injection to another session. On the next attempt, insert the needle more superficially and perform a test procaine injection until the correct placement is confirmed, then inject alcohol. If the first division remains paralyzed after alcohol injection, instruct the patient to protect the cornea. In case of accidental injection into the subarachnoid space during procaine administration, the patient may experience severe reactions such as dizziness, nausea, and vomiting. If such reactions occur, discontinue the injection immediately, place the patient supine with the head elevated, and allow rest for 1–2 hours until symptoms resolve. If significant spinal anesthesia reactions appear, collaborate with an internal medicine physician for symptomatic emergency management. Therefore, this block procedure should be performed with extreme caution.
**【Commentary】**
Trigeminal neuralgia is a refractory condition that is difficult to treat clinically. For non-surgical management of primary trigeminal neuralgia, acupuncture and nerve block therapy should be the first-line treatments. In early-stage patients with milder symptoms, acupuncture can achieve certain therapeutic effects. However, for more stubborn cases with multiple daily attacks (dozens of episodes per day), acupuncture may be combined with nerve block therapy. Precise selection of indications is crucial for the success of nerve block therapy; however, this approach carries a higher risk of complications and requires a high degree of accuracy, so caution is warranted when applying it. If the above methods fail to yield satisfactory results, they should be discontinued and surgical intervention should be considered. In summary, the clinical treatment of trigeminal neuralgia is challenging, and the recurrence rate after cure is high. Therefore, acupuncture, nerve block, and surgery are only several effective approaches to alleviating trigeminal neuralgia.
For the treatment of secondary trigeminal neuralgia, the first step is to address the underlying secondary lesion. Once the various secondary lesions are resolved, acupuncture can be applied to the remaining trigeminal neuralgia, yielding satisfactory results.