The trigeminal nerve has three divisions, including the ophthalmic nerve, maxillary nerve, which is primarily involved in facial sensation, and mandibular nerve, a mixed nerve, which is involved not only in sensation but also in the motor function of the muscles of mastication [1]. The most common cause of trigeminal nerve damage is dental procedures, but its other causes include local anesthesia, trauma, and tumor removal [2].

The compression of the trigeminal nerve by a tumor can cause facial sensory disturbances, including pain, numbness, and tingling. Therefore, the tumor is often removed when it reaches a specific size or symptoms appear. These tumors are typically located in the middle and posterior fossae, with meningiomas and large vestibular schwannomas being the most common [3].

This report describes the case of a temporomandibular disorder (TMD) with facial sensory abnormalities, resulting from trigeminal nerve transection after tumor removal surgery, which was successfully managed by integrative Korean medicine, including acupuncture, electroacupuncture, pharmacoacupuncture, Chuna manual therapy, wet-cupping therapy, and herbal medicine administration.

1. Medical history

A 39-year-old male developed left TMD and left facial sensory abnormalities immediately after trigeminal nerve transection during the removal of a trigeminal nerve tumor in 2018 (Fig. 1). He mentioned that the residual sensation on the left side of his face was approximately 20% normal, but he had not been evaluated for TMD.

Figure 1. BR-MRI after the resection of trigeminal nerve tumor: left acoustic neuroma status post resection of a trigeminal nerve tumor. BR-MRI, brain magnetic resonance imaging; AX T2 FLAIR, axial T2 fluid-attenuated inversion recovery; AX T2W_TSE, axial T2-weighted turbo spin-echo.

The left facial sensory abnormalities he experienced included numbness from below the left eye extending to the jaw. For his left TMD, the patient reported discomfort with jaw movement, bilateral temporomandibular joint (TMJ) stiffness and pain, and worsening fatigue-induced stiffness. Social history taking revealed that the patient had no history of smoking but he occasionally consumed alcohol.

There was no history of visits to other hospitals, and the total treatment period was limited to 3 weeks due to his plan of returning to the United States. His first hospital visit was on August 25, 2023, and the last one was on September 13, 2023, with a total of seven visits.

2. Radiography

Brain MRI is shown in Fig. 1.

3. Treatment

1) Acupuncture and electroacupuncture

Acupuncture treatment was performed using 0.25 × 40-mm disposable stainless steel needles (DongBang Acupuncture Inc.) for 20 minutes per session. The selected acupuncture points were GB3, LI18, ST6, ST7, SI19, and EX-HN5. Electrical stimulation at 4 Hz (STN-111; Stratek) was applied to both the ST7–SI19 acupoints at an intensity sufficient to induce a visible twitch in the inserted needle.

2) Pharmacoacupuncture

A single 0.5-cm³ dose of 1:30,000 bee venom (BV) was administered using a 1-cm³ disposable syringe (30 gauge; Hwajin Medical Co.) to both the ST7 acupoint and the middle of the masseter muscles, with 0.2 mL injected at each site during each session.

3) Chuna manual therapy

The practitioner placed both thumbs on the patient’s lower molars and encircled the patient’s lower jaw using the remaining four fingers of each hand. Then, the practitioner gently pressed down his fingers on the patient’s lower jaw in the direction of normal jaw movement, pulling it forward. This process was repeated approximately five times. Subsequently, the medial pterygoid compression technique was applied bilaterally to open the jaws. The patient underwent five sessions of Chuna TMJ therapy on August 25, August 30, September 4, September 11, and September 13.

4) Wet-cupping therapy

For the wet-cupping therapy, two tender points on both sides of the sternocleidomastoid, suboccipital, and trapezius muscles, totaling to six points, were selected. Wet-cupping was performed once during each visit for seven sessions.

5) Herbal medicine treatment

The herbal extracts of Jakyakgamcho-tang, comprising Paeonia lactiflora and Glycyrrhiza uralensis (2:1), were administered twice a day from August 25 to September 9 (Table 1).

Table 1 . The duration of the patient’s treatment and the number of sessions for each treatment method.

Treatment	2023/8/25	2023/8/30	2023/9/1	2023/9/4	2023/9/6	2023/9/11	2023/9/13
1. Acupuncture and electroacupuncture	O	O	O	O	O	O	O
2. Pharmacoacupuncture	O	O	O	O	O	O	O
3. Chuna manual therapy	O	O	X	O	X	O	O
4. Wet-cupping therapy	O	O	O	O	O	O	O
5. Herbal medicine	Taken twice a day, every day

4. Assessments

1) Patient-reported scales

The visual analog scale (VAS) for pain and Jaw Functional Limitation Scale-8 (JFLS-8) were used in the assessments. The patient completed both questionnaires on August 25, 2023, the date of the initial visit, and again on September 13, 2023, the last day of treatment.

2) Range of motion

TMJ radiography and maximum unassisted opening (MUO) measurements (in mm) were performed. TMJ radiographs was taken with the patient’s jaws open and closed, capturing both sides of the TMJ on the first (August 25, 2023) and last days of visits (September 13, 2023). Length was measured by connecting the midpoint between the first molars in the upper and lower jaws. The length of the MUO was measured using a ruler to determine the interincisal distance between the maxillary and mandibular reference teeth.

3) Patient’s interview

The patient was asked about his subjective feelings and any changes in symptoms, including the facial stiffness and numbness he experienced postoperatively, specifically at the end of the entire treatment on September 13, 2023.

5. Clinical outcomes

Before treatment, the pain VAS score was four at rest and greater when chewing; however, after treatment, the pain VAS score decreased to 0–1. Additionally, excluding the “swallow” item, which the patient had no discomfort from the beginning, all the other JFLS-8 items showed improvement after treatment. Particularly, significant improvements in chewing tough food or chicken and in opening the mouth wide to yawn were observed (Fig. 2).

Figure 2. Jaw Functional Limitation Scale-8 (JFLS-8).

As shown on the TMJ radiograph, the opening of the left TMJ increased from 26.93 mm before treatment to 36.65 mm after treatment, while the opening of the right TMJ increased from 27.64 mm before treatment to 36.81 mm after treatment (Fig. 3).

Figure 3. X-ray scans of the temporomandibular joint on both sides before and after treatment. The length was measured by connecting the midpoint between the first molars in the upper and lower jaws.

The MUO increased from 35 mm before treatment to 50 mm after treatment. It was also confirmed that the degree of deviation of the mandible to the left side decreased after treatment, as compared to that before treatment (Fig. 4).

Figure 4. Measurement of the maximum unassisted opening (mm) before and after treatment. The length of the MUO was measured to determine the interincisal distance between the maxillary and mandibular reference teeth. MUO, maximum unassisted opening.

The patient described his symptoms as follows: “My jaw movement felt restricted before treatment, but the stiffness decreased after treatment, and chewing became much easier. Before treatment, I could feel a dull sensation under the TMJ, similar to being numbed at the dentist, but this disappeared after the treatment (Fig. 5)."

Figure 5. The treatment assessments and subsequent sequence. TMD, temporomandibular disorder; VAS, visual analog scale; TMJ, temporomandibular joint; MUO, maximum unassisted opening.

There were no side effects or unexpected symptoms.

The patient visited Kyung Hee University Korean Medicine Hospital with complaints of TMD and facial sensory abnormalities following a trigeminal nerve transection. We can infer that the patient’s symptoms occurred through the following mechanisms. First, since the patient had pain and facial sensory abnormalities in the area from below the eye to the jaw, along with an abnormal TMJ movement, it indicated damage to the V2 and V3 branches of the trigeminal nerve. Second, the difficulty in mastication and deviation of the jaw to one side suggests problems with the temporalis and masseter muscles, TMJ capsules, and mandibular nerve. Finally, the continuous abnormal movement of these nerves and muscles can lead to TMJ inflammation, causing pain [4].

According to a meta-analysis published in 2023, the most effective treatments for chronic pain due to TMD include cognitive–behavioral therapy with biofeedback or relaxation therapy, therapist-assisted jaw mobilization, and manual trigger point therapy [5]. In another meta-analysis that managed TMDs by differentiating between masticatory muscle and joint issues, wet needling techniques were found to be the most effective treatment for masticatory muscle problems. Concurrently, non-steroidal inflammatory drugs were most beneficial for issues related to the TMJ itself [6].

However, since the patient did not wish to receive any analgesics, integrative Korean medicine treatments, including acupuncture, electroacupuncture, pharmacopuncture, Chuna manual therapy, wet-cupping therapy, and herbal medicines, were administered. Acupuncture is considerably more effective as compared to no treatment at all in alleviating TMJ and muscle pain, and its effectiveness is comparable to that of other treatments [7]. Additionally, acupuncture is reported to be as effective as Botox treatment and more effective than normal saline injections for the treatment of masticatory myofascial pain [8]. Electroacupuncture has been used to stimulate the growth of damaged nerve axons [9].

BV pharmacopuncture has anti-inflammatory and immunomodulatory effects. This treatment is particularly effective for arthritis [10]. Through the ST7 acupoint, the deep masseter and lateral pterygoid muscles were stimulated, as the superficial masseter muscle greatly contributes to mastication.

Chuna manual therapy promotes nerve regeneration [11], reduces pain by decreasing inflammation [12], and, as a form of exercise, prevents muscle atrophy [13]. Secondary pain was alleviated by increasing the TMJ’s locomotor activity and enhancing the axotomized neurons’ sprouting and growth [14]. These could be achieved through the help of a practitioner, improving the range of motion of the TMJ, and reducing the anxiety levels of patients who were afraid to move their jaws [15]. Additionally, Chuna manual therapy significantly increases the dendritic density and total neurite length, creating new functional adaptations [16]. Compression was applied to the elevation, protrusion, and contralateral lateral deviation of the mandible [17].

As restricted neck muscle movement can affect the movement of the TMJ [18], wet-cupping therapy was performed on the sternocleidomastoid, trapezius, and suboccipital muscles to remove exudates, reduce oxidative stress [19], and stimulate the peripheral nervous system, neurohormones, and circulatory and immune systems [20].

Given that the patient’s postoperative muscle tension and pain could be diagnosed as Qi stagnation and blood stasis from the perspective of Korean medicine, Jakyakgamcho-tang extracts were administered to the patient for their anti-inflammatory and analgesic properties.

In conclusion, the present case demonstrates the significance of using integrative Korean medicine as treatment for chronic TMD and facial sensory abnormalities due to nerve damage after surgery. However, this treatment approach has limitations, including the short outpatient treatment duration, wherein our patient was only treated for a duration of 3 weeks since he was living far from the hospital, and difficulty in distinguishing the effects of each treatment due to the comprehensive application of Korean medical treatments. Although the medical treatments for TMD are frequently administered in Korea, related studies still needed to be conducted. Therefore, if the TMD treatments applied to the present case are utilized in treatment protocols and further research is conducted, the effectiveness of Korean medicine in the treatment of TMD could be better supported.

Conceptualization: MSK, SHL. Data curation: MSK. Formal analysis: MSK, SHL. Investigation: MSK. Methodology: SHL. Project administration: SHL. Resources: SHL. Supervision: SHL. Visualization: MSK. Writing − original draft: MSK. Writing − review & editing: SHL, YSK, HGL, JSL, YJY.

The authors have no conflicts of interest to declare.

None.

The present study was approved by the Kyung Hee University Institutional Review Board (IRB no. KOMCIRB 2024-06-003). Before the study, written consent for the publication of this case report was obtained from the patient.