Electroacupuncture for the treatment of infraorbital nerve injury caused by zygomaticomaxillary complex fracture: a case report

Abstract

Background

Zygomaticomaxillary complex (ZMC) fractures often lead to infraorbital nerve (ION) injury, which is characterized by facial numbness and sensory impairment. For patients with poor surgical outcomes or those refusing surgery, effective alternative interventions are required. In this paper, we report the clinical outcome of Electroacupuncture (EA) in a patient with ION injury caused by ZMC fracture.

Case description

A 36-year-old East Asian (Han Chinese) woman presented with persistent numbness of the left zygomatic face, nose, upper lip, and gums due to infraorbital nerve injury after a left ZMC fracture. The patient refused surgery and underwent 8 weeks of EA treatment (3 times per week) at selected points including GV26, left ST2, SI18, and bilateral LI4, supplemented by 2-Hz continuous wave electrical stimulation. After treatment, Semmes–Weinstein monofilament test (SWMT) values were reduced, two-point discrimination perception (2PD) was shortened, visual analog scores (VAS) were reduced, and electrophysiological tests showed significant improvement in nerve conduction latency and wave amplitude on the affected side. After 3 months of follow-up, the patient was left with only a slight numbness of the upper gingiva on the affected side.

Conclusions

EA can improve the symptoms of ION injury after ZMC fracture. This study is a single-case report, and further large-sample studies are needed to verify the efficacy of EA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13256-026-06027-6.

Introduction

Zygomaticomaxillary complex (ZMC) fractures are a common type of maxillofacial trauma, accounting for approximately 15% of all facial fractures [1]. Typical clinical signs and symptoms of ZMC fractures include facial depression, diplopia, and infraorbital nerve (ION) injury caused by fracture lines involving the infraorbital canal and foramen, leading to numbness in the affected cheek, upper lip, and gingiva [2, 3]. Depending on the evaluation method, ION injury occurs in 30–80% of midfacial fractures [4, 5]. Most scholars suggest that for moderate to severe ION injuries (e.g., Sunderland grades III–IV), nerve decompression surgery combined with fracture reduction is recommended. Conservative treatments, such as neurotrophic medications and hyperbaric oxygen therapy, may be considered if the ZMC fracture exhibits minimal displacement [6–8]. However, some studies indicate that surgical intervention for ZMC fractures with minor displacement does not improve neurological recovery, and postoperative complications such as persistent sensory disturbances, intraoperative nerve injury, and high costs remain concerns.

EA which integrates traditional acupuncture with modern electrical stimulation, has emerged as a potential adjunctive therapy for peripheral nerve injury [9–11]. Studies suggest that EA may support nerve regeneration by promoting the secretion of neurotrophic factors and activating Schwann cells while also alleviating neuropathic pain through the modulation of inflammatory cytokines and central pain pathways [12–16]. This case report describes the clinical course of a patient with ION injury following a ZMC fracture, who refused surgical intervention and subsequently underwent EA treatment, resulting in significant improvement of sensory function.

Case presentation

The patient was a 36-year-old East Asian (Han Chinese) female who presented with a 1-week history of persistent numbness in the left zygomatic region, nasal ala, upper lip, and upper gingiva. In November 2024, she fell from a bicycle, resulting in direct trauma to the left side of her face. This caused left zygomatic pain, swelling, and persistent numbness in the left nasal ala, upper lip, upper gingiva, and infraorbital region, without visual impairment or restricted mouth opening. Palpation of the affected cheek elicited numbness and tingling. The patient initially self-treated with ice and subsequently visited a local hospital. A maxillary CT scan with three-dimensional reconstruction revealed fractures of the left lateral orbital wall, anterior and posterior walls of the left maxillary sinus, left zygomatic bone, and zygomatic arch, accompanied by soft tissue swelling, pneumatosis, and possible hematocele in the left maxillary sinus (Fig. 1). Based on clinical symptoms and imaging findings, a diagnosis of left ZMC fracture with infraorbital nerve injury was confirmed. The patient declined surgical intervention and opted for conservative treatment under medical advice. She was subsequently referred to the acupuncture department of the First Affiliated Hospital of Anhui University of Chinese Medicine. Physical examination findings included mild ecchymosis over the left zygomatic region and tenderness (+) at the infraorbital foramen. Sensory function assessments revealed the following: Semmes–Weinstein monofilament testing (SWMT): affected infraorbital region: 4.31 (contralateral side: 2.83). Two-point discrimination (2PD): affected infraorbital region: 15 mm (contralateral side: 6 mm). Visual Analog Scale (VAS): 7 points. Sensory nerve conduction study (SNCS): latency: affected infraorbital region: 3.5 ms (contralateral side: 2.3 ms). Amplitude: affected infraorbital region: 24.5 μV (contralateral side: 6.8 μV). Given the patient's concerns about surgery and her proactive pursuit of non-pharmacological therapies, we selected EA as the primary rehabilitation intervention following thorough communication with the patient.

Fig. 1.

Three-dimensional computed tomography (CT) imaging

Acupuncture treatment

The patient received treatment using stainless steel acupuncture needles (0.35 mm × 40 mm; Suzhou Tianxie Acupuncture Devices Co., Ltd., Suzhou, Jiangsu, China) inserted to a depth of approximately 30 mm. The selected acupoints included Renzhong (GV26), left Sibai (ST2), Quanliao (SI18), and bilateral Hegu (LI4) (Table 1; Fig. 2). The electrodes of an EA device (HuaTuo SDZ-V Pulse Acupuncture Therapeutic Apparatus) were connected to Sibai (ST2) and Quanliao (SI18). The device was initially set to zero, with a continuous wave mode at 2 Hz frequency selected [17]. The power was then turned on, starting at an intensity of 1 mA. The intensity was gradually increased based on the occurrence of rhythmic muscle contractions and patient tolerance, with a maximum threshold of ≤ 3 mA. Each session lasted 30 min. After treatment, the device was turned off, electrodes were removed, and needles were withdrawn. The patient underwent three sessions per week for eight consecutive weeks, administered by the same experienced acupuncturist. No medications were used during the treatment period.

Table 1.

Framework of the acupuncture point prescription

Acupoints	Locations
SiBai (ST2)	On the face, directly below the pupil, in the depression of the infraorbital foramen
QuanLiao (SI1)	On the face, in the depression directly below the outer canthus (outer corner of the eye), at the lower border of the zygomatic bone
RenZhong (GV26)	On the face, at the junction of the upper one-third and middle one-third of the philtrum groove
HeGu (LI4)	On the dorsum of the hand, between the 1st and 2nd metacarpal bones, approximately at the midpoint of the radial side of the 2nd metacarpal bone

Fig. 2.

Acupoint selection for needling. Arrows indicate the location of bilateral LI4 (Hegu) on the patient's hands

Outcome measurements

This study employed a series of validated tools widely used in the assessment of peripheral nerve injury. The SWMT and 2PD serve as sensitive indicators for evaluating the recovery of tactile and discriminative sensation [18–20]. The VAS was utilized to quantify subjective sensory abnormalities [21]. The SNCS provided objective quantitative data on neurophysiological function [22].Therapeutic outcomes were assessed weekly using SWMT, 2PD, and VAS. SNCS were performed at baseline (week 0), week 4, and week 8. After 8 weeks of EA therapy, the patient exhibited reduced SWMT log values, shortened 2PD distances, and decreased VAS scores (Fig. 3). Numbness and pain in the left infraorbital region, nasal ala, and upper lip resolved, with only mild residual numbness in the left upper gingiva. Pre- and post-treatment electrophysiological assessments are summarized in Table 2. Upon completion of the treatment cycle, the patient underwent a telephone follow-up. At the 3-month follow-up, she reported overall physical comfort, with no recurrence of sensory disturbances except for persistent mild numbness in the left upper gingiva. A timeline of symptom progression and treatment effects is shown in Fig. 4.

Fig. 3.

Change of VAS, 2PD, SWMT during the treatment course. a VAS; b 2PD; c SWMT

Table 2.

Sensory nerve conduction study results

Sensory nerve conduction study		0 week		4 weeks		8 weeks
Right (healthy side)	Latency (ms)	2.3	2.4		2.3
	Amplitude (mV)	24.5	23.8		26.9
Left (affected side)	Latency (ms)	3.5	3		2.9
	Amplitude (mV)	6.8	10.5		14.3
Recovery rate (%)		27.8	44.1		53.2

Fig. 4.

Timeline of symptom progression during disease onset and acupuncture treatment

Discussion

This report presents a case of ION injury following a ZMC fracture. The patient, who declined surgical intervention, exhibited symptomatic and electrophysiological improvement after an 8-week course of EA, which was sustained at the 3-month follow-up. This case provides an observational example for exploring the potential application of EA in such traumatic neuropathies.

The acupoint selection integrated empirical tradition with modern anatomical considerations. ST2 (Sibai) and SI18 (Quanliao) were targeted over the ION distribution area, consistent with the principle of local stimulation [23]. GV26 (Renzhong) was chosen based on its traditional indication for facial disorders. The bilateral application of LI4 (Hegu) followed the classic distal point principle for treating facial regions. It has been proposed that the efficacy of such distal points might relate to the neurophysiological basis of somatotopic representation in the sensory cortex, where the hand and face areas are adjacent, offering a perspective for interpreting distal point effects [24, 25]. The combination of local and distal points used here represents an experience-based strategy within acupuncture practice. Given that individualized treatment often takes precedence in traditional Chinese medicine practice, the acupoint selection and EA protocols described herein should be regarded as specific examples. Their general applicability may be influenced by the inherent characteristics of this therapeutic system.

The functional improvement observed in this patient may stem from the dual effects of EA in promoting nerve repair and controlling neuropathic pain. Regarding nerve repair, EA likely facilitates regeneration by modulating non-coding RNA networks. Studies show that EA downregulates lncRNA GAS5, thereby elevating miR-21 and enhancing Schwann cell proliferation and migration [26]. Concurrently, EA downregulates miR-1b, alleviating its inhibition on Brain-derived neurotrophic factor and subsequently supporting Schwann cell survival and axonal growth [27].Regarding pain control, EA acts through multi-level mechanisms. Peripherally, EA downregulates P2X3 receptor expression in the dorsal root ganglion and modulates the TRPV1 channel, with low-frequency (2 Hz) EA demonstrating superior efficacy [28]. At the spinal level, EA modulates neurotransmitters including opioids, serotonin, and norepinephrine, effectively inhibiting central sensitization to alleviate pain [29–31]. Notably, low-frequency EA (2–10 Hz) generally induces more potent and sustained relief in neuropathic pain [32].These molecular mechanisms, based on animal studies, provide a possible explanation for the sensory recovery observed in this case.

While spontaneous recovery of nerve injury remains a possibility, the temporal correlation between improvement and the treatment course, the concordant positive trends in both subjective and objective measures, and the short-term stability of outcomes suggest that EA may have actively facilitated the recovery process. Considering that natural recovery from Sunderland grade III–IV nerve injuries is often incomplete and protracted [33], the recovery pattern observed in this case warrants attention.

In current clinical practice, surgical decompression remains the standard of care for ION injuries associated with significantly displaced ZMC fractures. However, this approach carries risks of infection, scarring, and iatrogenic nerve injury [34, 35]. Notably, some comparative studies have found no significant difference in the extent of sensory recovery between patients who underwent infraorbital canal decompression and those who did not [36]. Alternatively, neurotrophic pharmacotherapy represents a relatively passive conservative option. Within this context, the present case suggests that for specific patient populations, such as those declining surgery, EA may be explored as a low-cost complementary or alternative treatment option, underscoring the importance of individualized therapy.

In this particular case, the EA procedure was well-tolerated without observed adverse events, such as bleeding, hematoma, infection, or exacerbated pain. When administered by qualified practitioners, EA represents a low-risk intervention [37, 38]. However, standard clinical contraindications must still be observed; for instance, caution is warranted in patients with bleeding disorders, local infections, or implanted cardiac pacemakers [39].

Limitations

As a single-case report, this study has inherent limitations. We cannot establish a causal relationship between EA and nerve recovery, as we cannot completely rule out the placebo effect or the influence of the natural course of the injury. Furthermore, the EA mechanisms discussed in this paper is primarily extrapolated from prior basic science and clinical research on other types of neurological injury, rather than directly derived from molecular or imaging evidence obtained from this specific patient. Therefore, these hypothesized mechanisms remain speculative and represent a gap in current understanding. Furthermore, the follow-up period in this study was 3 months. Although efficacy remained stable during this time, the lack of longer-term follow-up data precludes confirmation of the durability of these improvements. Future large-scale, well-controlled randomized clinical trials with extended follow-up periods are needed to confirm the efficacy of EA for traumatic ION injury.

Conclusion

This case highlights EA as a promising adjunctive strategy for managing post-ZMC fracture nerve injuries, particularly in patients with suboptimal surgical outcomes or medication intolerance. EA demonstrated marked clinical improvement in ION injury symptoms, with low cost and minimal adverse effects. However, this single-case report necessitates further validation through large-scale randomized controlled trials to confirm its efficacy.

Abbreviations

EA

Electroacupuncture

ZMC

Zygomaticomaxillary Complex

ION

Infraorbital nerve

SWMT

Semmes–Weinstein Monofilament Testing

2PD

Two-Point Discrimination

VAS

Visual analog scale

SNCS

Sensory Nerve Conduction Study

Author contributions

ZY conceived the study and prepared the manuscript; BC conceptualized the research; FH and PW and ZH and LW collected and analyzed the data; BZ and JY revised the manuscript. All authors contributed to the article and approved the submitted.

Funding

This work was supported by State Administration of Traditional Chinese Medicine national famous traditional Chinese medicine practitioners Yang Jun inheritance studio grant number: Anhui traditional Chinese medicine development secret [2022] No. 19.

Availability of data and materials

All data available are included in this article and its supplementary material files. Further inquiries can be directed to the corresponding author.

Declarations

Ethics approval and consent to participate

Ethical approval is held to be unnecessary by the Medical Ethics Committee of The First Affiliated Hospital of Anhui University of Chinese Medicine, as this is a single, rare case encountered during clinical practice.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests

The authors declare that they have no competing interests.