Referred Pain Due to Greater Occipital Nerve Entrapment as a Cause of Failed Cervical Spine Surgery Syndrome

GON Entrapment as a Cause of Failed Cervical Spine Surgery

Article information

Nerve. 2025;11(2):46-54

Publication date (electronic) : 2025 October 20

doi : https://doi.org/10.21129/nerve.2025.00759

¹Department of Neurosurgery, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

²Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

Corresponding author: Byung-chul Son Department of Neurosurgery, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea Tel: +82-2-2258-6122 Fax: +82-2-594-4248 E-mail: sbc@catholic.ac.kr

Received 2025 May 20; Revised 2025 July 13; Accepted 2025 July 14.

Abstract

This report discusses a case of failed cervical spine surgery syndrome attributed to referred pain from greater occipital nerve (GON) entrapment. Although occipital neuralgia is commonly recognized as a symptom of GON entrapment, this condition typically manifests as continuous aching, tightening, and pressure-like pain across the GON distribution. Pain from chronic suboccipital and neck discomfort due to GON entrapment is often accompanied by referred pain in the orofacial and submandibular neck areas, as well as in the upper extremity. A lack of understanding of referred pain from chronic suboccipital and neck issues associated with GON entrapment may lead to unnecessary spinal surgery for asymptomatic degenerative lesions of the cervical spine. The anatomical basis for pain referral to the facial trigeminal area from GON entrapment involves the convergence of nociceptive inflow from the high cervical C1-3 structures and the trigeminal orofacial area onto the dorsal horn of the cervical spinal cord (trigeminocervical complex [TCC]) from the C2 segment to the medullary dorsal horn (MDH). Persistent noxious input due to GON entrapment may induce sensitization and hypersensitivity in the second-order neurons in both the TCC and MDH in the caudal trigeminal nucleus and high cervical cord.

Keywords: Failed back surgery syndrome; Greater occipital nerve; Occipital neuralgia; Nerve compression syndromes; Neuralgia; Pain

INTRODUCTION

Nociceptive afferent input from occipital and suboccipital structures is mediated by small-diameter afferent fibers in the upper cervical roots, terminating in the dorsal horn of the cervical spinal cord from the C2 segment to the medullary dorsal horn (MDH)1,5,22). The primary afferent contribution is facilitated by the C2 cervical root, which peripherally corresponds to the greater occipital nerve (GON)5,24). Similar to trigeminal sensory neurons, these cervical neurons exhibit a high convergence of input from neck muscles and skin4,6). Meanwhile, trigeminal nociceptive afferent input is transmitted to second-order neurons in the superficial and deep layers of the MDH within the trigeminocervical complex (TCC)3,4,6). The TCC extends from the trigeminal nucleus caudalis to the C2-3 segment12,15). This integration of nociceptive inputs from trigeminal and upper cervical structures into the MDH and TCC may elucidate the frequent occipital pain referrals observed in patients with primary headache4).

Occipital neuralgia is characterized by paroxysmal stabbing pain originating from the distribution of the GON and is predominantly primary in origin11,37). Recent studies, however, have indicated that GON entrapment within the trapezial tunnel—the area where the aponeurotic edge of the trapezius muscle attaches to the superior nuchal line—is a leading cause of occipital neuralgia9,20,21,30,31). The GON transmits nociceptive afferent information from the temporo-occipital area, vertex, suboccipital region, and neck21,36). Consequently, the GON represents the principal sensory afferent passing through the C2 root, with this information being relayed directly to the high cervical dorsal horn where the TCC is situated3,19,34). GON entrapment typically results in aching, tightening, and pressure-like pain in the posterior head and neck, typical of GON distribution, as well as occipital neuralgia30,31). Moreover, the chronic, incessant, and noxious inputs from the entrapped GON are associated with sensitization and hypersensitivity of second-order neurons in the TCC, leading to referred pain in the trigeminal distribution5,14,16-18,23,27-33). Indeed, this pain has been reported to not only affect the trigeminal nerve area but also extend throughout the body, including the upper and lower extremities5,14,16-18,23,27-33). Therefore, the clinical manifestations of TCC hypersensitivity induced by chronic GON entrapment are varied, considering the occurrence of generalized extremity pain and pain in facial and occipital regions5,14,16-18,23,27-33).

A failure to recognize that pain in the occipital and neck areas caused by GON compression can refer to the face and arms may lead to the misdiagnosis of these symptoms as a variety of other conditions5,14,16-18,23,27-33). Chronic pain in the suboccipital region and neck due to GON entrapment often requires differentiation from conditions such as cervicogenic headache, trapezial myofascial pain, and cervical disc herniation5,14,16-18,23,27-33). This report presents a case of cervical spine surgery addressing chronic pain in the occipital and neck regions associated with chronic GON compression. Diagnosing GON entrapment can be challenging when the pain attributed to the GON is misinterpreted as radiating solely to the occipital vertex.

CASE REPORT

A 55-year-old male patient presented with chronic bilateral temporo-occipital and bilateral neck and shoulder pain for 5 years. The pain in his bilateral temporal occipital region actually started about 10 years ago without any specific cause and recurred annually for one or two months each year. At that time, he was treated with medication, neck physical therapy, and injection therapy, managing to live his daily life without specific issues. Five years ago, he abruptly experienced a lightning-like pain radiating from the retro-auricular suboccipital to the temporo-occipital vertex. Subsequently, the pain in his suboccipital and lateral neck regions extended to his shoulders, continuing throughout the day (Fig. 1A). The pain was constant, characterized by aching and squeezing sensations accompanied by a sense of pressure and tightening.

Fig. 1.

Schematic diagram illustrating the distribution and characteristics of chronic pain. (A) The patient’s pain was localized in the bilateral temporo-occipital, neck, shoulder, and interscapular neck areas. The affected area is depicted as a gray area. (B) The patient experienced pain in the bilateral jaw and anterior neck, as well as periorbital areas. (C) In addition to head and neck, and facial pain, spontaneous pain occurred in the mid-sternal chest, left upper arm, bilateral inguinal and lateral thigh, and back.

Along with the shoulder pain, he also experienced a tightening sensation accompanied by numbness in his lower gums and jaw angle on both sides (Fig. 1B). Dental examinations, including oral surgery, did not reveal any specific abnormalities. As the pain in his posterior head, neck, and shoulders intensified, he began to experience intermittent periorbital pain and blurred vision in both eyes. Additionally, he felt mild numbness and a cold sensation on the lateral side of his left upper arm (Fig. 1C). Over the past five years, he had been treated for migraine, tension headaches, cervicogenic headache, and cervical disc herniation at various clinics and hospitals for the last five years. He received physical therapy and acupuncture, along with multiple repeated interventional pain blocks and tender point injections to his neck and shoulders on a nearly weekly basis.

Three years ago, his chronic shoulder pain was diagnosed as a rotator cuff injury, and he underwent surgery. However, the surgery failed to alleviate the pain in both shoulders. A percutaneous neuroplasty was then performed for his chronic neck pain, which radiated to his occipital and shoulders, but it was ineffective. Subsequently, he was diagnosed with degenerative cervical disc disease and underwent anterior cervical discectomy and fusion surgery at the C5-6 and C6-7 levels (Fig. 2). Unfortunately, this cervical disc surgery also did not resolve his chronic pain. Over time, he developed intermittent stabbing pains in the sternal area of his chest. Cardiac examination did not reveal any specific abnormalities. With no other options, he continued taking non-steroidal anti-inflammatory drugs, muscle relaxants, and pain relievers as he had before his neck and shoulder surgeries, and participated in physical therapy and injections into the affected areas.

Fig. 2.

Imaging findings of the cervical spine in a patient with greater occipital nerve (GON) entrapment who underwent cervical spine surgery for chronic occipital and neck pain. (A) An X-ray image of the cervical spine showing anterior cervical discectomy and fusion at C5-6 and C6-7. (B) A T2-weighted sagittal magnetic resonance image of the cervical spine reveals mild degenerative cervical disc protrusions. (C) T2-weighted axial images of the cervical spine at the C5-6 (left) and C6-7 levels (right). Left-sided disc protrusion was noted at the level of C6-7 (right). However, there are no significant findings at the C5-6 level (left).

One year prior to presentation, the patient experienced persistent pain in the bilateral temporo-occipital region, neck, and shoulders, accompanied by bilateral periorbital, jaw, and gum discomfort. He also began to experience intermittent, dull aching and burning sensations in the bilateral groin areas and lateral thighs, as shown in Fig. 1C. This occurred spontaneously, irrespective of his posture or activities. He eventually sought consultation at the author’s outpatient clinic to determine the cause of his facial and neck pain, which was accompanied by chronic temporo-occipital pain.

Upon examination, his pain was found to localize to the bilateral suboccipital areas and the lateral sides of the neck, radiating to the temporo-occipital vertex and down to the deltoid and shoulder areas. No tenderness or allodynia was detected in the painful regions. The patient exhibited no limitation in neck motion, and no significant sensory changes were observed in the left upper extremity and the lateral aspect of the forearm, where he reported feelings of numbness and coldness. Motor strength was normal in both the upper and lower extremities. Deep tendon reflexes were normoactive. Cranial nerve examination, including facial sensation, did not reveal any abnormalities. His arm pain did not worsen during a Spurling test or with hyperabduction of the left arm. Systemic diseases were ruled out as potential causes of the pain, and laboratory tests showed no abnormalities. The patient rated his pain at a 5 or 6 out of 10 on the numerical rating scale-11 (NRS-11).

Plain X-ray imaging of the cervical spine showed anterior cervical interbody fusion at C5-6 and C6-7. His preoperative magnetic resonance imaging (MRI) scan, conducted 3 years prior to the cervical spine surgery, was reviewed and depicted in Fig. 2. A left-sided posterolateral disc protrusion was observed at the level of C6-7 , but no abnormality was noted at C5-6. Subsequent cervical MRI, performed one year post-surgery, confirmed the absence of disc protrusion at C6-7. Additionally, the brain MRI showed no abnormalities. No abnormalities were detected in the computed tomographic (CT) scan of the cervical spine, which was undertaken to examine structural lesions from the C2 nerve root to the GON. Both electromyography and nerve conduction velocity tests showed no signs of cervical radiculopathy or peripheral neuropathy.

Given the potential for referred trigeminal and extra-trigeminal, generalized pain due to GON entrapment, a bilateral occipital nerve block (ONB) with 2 mL of 2% lidocaine was performed. This treatment reduced the severity of occipital pain and associated with jaw and neck discomfort by 80% for 6 hr. A similar temporary improvement was noted during the second ONB, conducted two weeks later, which alleviated bilateral retro-auricular suboccipital, neck, and jaw pain for about 12 hr. Considering the chronic and refractory nature of the pain and the possibility of referred pain due to chronic GON entrapment, exploration and decompression of GON were recommended after obtaining written informed consent.

Decompression of the bilateral GONs was performed using an oblique, paramedian approach with a microscope6,8-19). The procedure initially targeted the distal branch of the GON passing through the trapezial canal. Under general anesthesia, bilateral 3-cm long paramedian oblique incisions were along the presumed course of the GON. Identification and tracing of the small visible distal branch in the subcutaneous tissue led to the main GON branch, which was entrapped at the tendinous aponeurotic edge of the trapezius muscle (Fig. 3). This specific site was confirmed as the primary entrapment location. The aponeurotic edge was dissected, and the GON’s proximal course was fully released by dissecting around the semispinalis capitis muscle beneath the trapezius up to the point where the GON emerges (Fig. 3). Bilateral decompression of the GONs was successfully accomplished.

Fig. 3.

Intraoperative images showing the entrapment of the greater occipital nerve (GON) during decompression. (A) Intraoperative images showing severe entrapment of the right GON (white arrows) by the fibrous, with the aponeurotic edge of the trapezius muscle (black arrows) along the superior nuchal line. The inset shows the direction of the image and the location of the incision. (B) Intraoperative image after decompression of the right GON (white arrows) with division of the trapezial aponeurosis (black arrows). The most severe part of GON constriction is indicated by a white arrowhead. (C) Intraoperative image showing entrapment of the left GON (white arrows) with elevation of the aponeurotic edge of the trapezius muscle (black arrows). The inset shows the direction of the image and the location of the incision. (D) Intraoperative image following decompression of the left GON (white arrows), achieved through division of the trapezial aponeurosis (black arrows). The white arrowhead indicates the occipital artery, which has been dissected from the left GON.

The beneficial effects of GON decompression became evident the day after surgery. The patient reported a significant reduction in persistent pain and discomfort in the bilateral temporo-occipital, suboccipital, lateral neck, and deltoid areas with an approximately 50% improvement compared to the baseline. Concurrently, it was reported that the pain in the bilateral inguinal region, thighs, and left arm was markedly alleviated.

Two months post-operatively, the pain in the back of the head, neck, and limbs had significantly improved, no longer interfering with daily activities. Numbness and tingling of the occipital vertex following GON decompression surgery also showed considerable improvement. The pain in the jaw and gums was mild (NRS 2-3/10) but would often intensify for 2 to 3 hr when the patient felt tired or stressed. Continued medication was necessary. By the fourth month post-surgery, the patient reported substantial relief from the temporo-occipital region as well as the facial, jaw, and gum area. He reported the absence of tightening pain in his neck and shoulders, and no paresthesia in his left arm. He mentioned that his symptoms were virtually resolved, eliminating the need for medication. Furthermore, he noted that the pain experienced prior to his cervical spine surgery three years earlier had dissipated following GON decompression.

Seven months post-surgery, the patient reported an approximately 80% reduction in pain in his occipital and neck regions. He felt no need for further follow-up. He used gabapentin 300 mg and Ultracet® as analgesics only when necessary, limiting their use to 3 to 5 days a month as required. One year after surgery, he experienced intermittent discomfort in the occipital and neck areas, but no further medication was required (NRS 2/10).

DISCUSSION

1. Entrapment of the GON

The GON originates from the medial branch of the dorsal rami of the second cervical root1). Additionally, it receives a branch from the dorsal rami of the C3 nerve2). It ascends through the semispinalis capitis muscle and runs posterolaterally before emerging onto the scalp by piercing the aponeurotic fibrous sling situated between the trapezius and sternocleidomastoideus muscles near their attachment to the superior nuchal line2). This aperture is a frequent site of GON entrapment and has been termed the trapezial tunnel21,37). After passing through the aponeurotic sling of the trapezial tunnel, the GON broadens along its course to the periphery, a feature that distinguishes it from other peripheral nerves21,36). This characteristic is considered significant to GON entrapment, as the widening of the nerve increases its susceptibility to entrapment, especially within the rigid trapezius aponeurosis21).

2. Anatomical Basis of Pain Distribution in GON Entrapment in Head and Neck

Nociceptive afferent inflow from the occipital and suboccipital structures is mediated by small-diameter afferent fibers in the upper cervical roots that terminate in the dorsal horn of the cervical cord, extending from the C2 segment up to the MDH of the caudal trigeminal nucleus1). The major afferent contribution is facilitated by the C2 spinal root, which is peripherally represented by the GON5). Pain associated with GON entrapment has been reported to be distribute to not only to the suboccipital area but also to the vertex, temples, retro-auricular and subauricular regions, jaw angle, and posterolateral neck5,14,16-18,23,27-29,32,33). The GON receives communicating branches from the third occipital nerve2). The third occipital nerve serves as the superficial medial branch of the dorsal ramus of the third cervical nerve2). The communicating branches of the third occipital nerve merge with the cutaneous branches of the GON and the lesser occipital nerve (LON)2). The LON is primarily originates from the ventral rami of the second cervical nerve, though it also receives contributions from the third occipital nerve2,23,27).

Additionally, the GON communicates with other nerves distributing sensations to the occipital and anterolateral neck2,23,27). Alongside its connections with the lesser and third occipital nerves, communications with the superficial auriculotemporal nerve, which is a terminal branch of the mandibular division (V3) of the trigeminal nerve and the greater auricular nerve of the cervical plexus, have been reported. Due to these anatomical relationships, GON entrapment may cause ear and peri-auricular pain and can radiate to the jaw angle and submandibular area5,14,16-18,23,27-29,32,33).

The LON, primarily derived from the ventral rami of the second cervical nerve, forms part of the cervical plexus along with other nerves, such as the greater auricular nerve, transverse cutaneous nerve, and suprascapular nerve, which originate from the ventral rami of the second, third, and fourth cervical nerves. These nerves supply the cutaneous branches to the anterior and lateral portions of the neck. The LON communicates effectively with the GON, and it occasionally originates from the GON2,36). It connects with the greater auricular, GON, and the auricular branches of the facial nerve2). Consequently, pain associated with GON entrapment can also radiate to the territories of the LON, the greater auricular nerve, the auricular branch of the facial nerve, and the auriculotemporal nerves through comprehensive communication with the LON27). In addition, its extensive communication with the cervical plexus can also cause pain in the anterolateral neck and shoulder27).

3. Referred Trigeminal and Extra-trigeminal Generalized Referred Pain in GON Entrapment

Chronic noxious afferent input from the entrapment of the GON can lead to sensitization and hypersensitivity of secondary neurons in the TCC, resulting in referred pain within the facial trigeminal distribution5,14,16-18,23,27-33).

The nociceptive afferent inflow from the occipital and suboccipital structures is conducted by small-diameter afferent fibers in the upper cervical roots, terminating in the dorsal horn of the cervical cord, which extends from the C2 segment to the MDH of the caudal trigeminal nucleus10). The C2 spinal root, which is peripherally represented by the GON, plays a major afferent role in transmitting sensory signals5). Noxious inputs from the receptors on the distal end of the fifth nerve terminate in the subdivisions of the spinal trigeminal nucleus and upper cervical cord, activating second-order neurons11). The spinal trigeminal sensory nucleus (Sp5) comprises three subnuclei: Sp5O (oralis), Sp5I (interpolaris), Sp5C (caudalis)38). Sp5C is referred to as the MDH because it uniquely features a layered structure and a morphological and functional organization comparable to that of the spinal dorsal horn13,26,38). Thus, nociceptive afferents from the high cervical region and the trigeminal system converge at the second-order nociceptive neurons of the MDH and TCC in the caudal trigeminal nucleus and upper cervical cord3,4). The convergence of nociceptive trigeminal and occipital afferent input in the spinal trigeminal nucleus and the dorsal horn of the upper cervical cord constitutes an anatomical basis for central sensitization5,6,10,12,14-18,23,27-33).

Chronic noxious input from GON entrapment can induce sensitization and hypersensitivity in second order neurons within the TCC and the MDH of the caudal trigeminal nucleus and high cervical cord5,14,16-18,23,27-33). This referral to pain to the orofacial area is not limited to the V1 (ophthalmic) region but also includes the V2 (maxillary) and V3 (mandibular) regions16,18). It may even lead to hemifacial sensory changes14,32,33). Referred pain from GON entrapment has also been reported to cause deep ear pain28). Pain resulting from GON compression can extend beyond the facial areas, which are the distribution area of the trigeminal nerve, affecting the entire body, including the arms and legs14,33).

For this extra-trigeminal, generalized extension of referred pain from GON entrapment, Hyung and Son14) as well as Son and Lee33) proposed two explanations. Firstly, they suggested that generalized pain may be caused by sensitization of third-order nociceptive neurons in the thalamus7). Secondly, they speculated that spontaneous pain could manifest throughout the body owing to dysfunction of the descending brainstem pain-modulating pathway due to sensitization and hyperexcitation of the MDH and trigeminal brainstem sensory nuclear complex25,35).

4. Differentiating cervical radiculopathy from neck pain associated with GON entrapment

In the current case, an asymptomatic degenerative lesion of the cervical spine, potentially the source of upper extremity pain, was incidentally discovered in a patient with chronic GON entrapment. The patient subsequently underwent 2-level cervical discectomy and fusion surgery. Therefore, it is crucial to differentiate chronic neck pain associated with GON entrapment from the radicular pain of more common cervical spine disorders for an accurate diagnosis. Common cervical pathologies such as cervical disc disease or spondylosis typically lead to nerve root compression, manifesting as neck pain, stiffness, radiating paresthesia, and weakness in the affected cervical roots8).

In this case, the patient presented with chronic occipital and neck pain, along with pain in the deltoid and medial scapular area on both sides. Although an MRI of the cervical spine revealed a left-sided disc herniation at the C6-7 vertebrae (Fig. 2), bilateral occipital pain and shoulder pain are not typical symptoms of cervical radiculopathy. The same is true for pain experienced in both eyes and the jaw. Although numbness and coldness were in the left arm, they lacked a specific dermatomal distribution. Furthermore, this non-dermatomal pain in the limbs was not accompanied by any objective neurological or musculoskeletal abnormalities.

Occipital neuralgia is well recognized as a symptom of GON entrapment. However, the paroxysmal stabbing pain characteristic of occipital neuralgia does not encompass all symptoms of GON entrapment5,14,16-18,23,27-33). GON entrapment typically induces continuous aching, tightening, and pressure-like pain across the GON distribution, accompanied by intermittent stabbing pain associated with classical occipital neuralgia5,14,16-18,23,27-33). Chronic aching and pressure-like, tightening pain in the neck and shoulders, coupled with suboccipital pain, are major symptoms of GON entrapment5,14,16-18,23,27-33). The current case is unique in that the referred pain due to GON entrapment extended not only frequently to the face but also to the extremities. It has previously been reported that referred pain due to sensitization of TCC and MDH by GON entrapment can manifest in both the upper and lower extremities14,33). The pain in the arm and leg resolved promptly, coinciding with amelioration of the referred pain involving the bilateral periorbital and jaw areas following GON decompression.

Considering the pathogenesis of referred trigeminal facial pain due to chronic GON entrapment based on the convergence of trigeminocervical afferents and subsequent sensitization of secondary neurons in TCC2,15,21), the neuroanatomical foundation for pain referral to the extremities stems from GON distribution and connectivity. The resolution of bilateral facial and jaw pain, along with concurrent chronic neck, shoulder, and limb pain due to GON decompression, heightened the sensitivity of the TCC.

CONCLUSION

Pain from chronic GON entrapment radiates from the suboccipital and lateral neck to the upper head, lower neck, and shoulders. Concurrently, sensitization and hypersensitivity of the TCC may cause referred pain to the face, jaw, and arms. Recognizing the referred pain associated with chronic GON entrapment can prevent unnecessary cervical spine surgery for chronic neck pain and nonspecific arm pain. Surgery for degenerative cervical spine lesions should not be performed based solely on imaging findings and medical refractoriness.

Notes

No potential conflict of interest relevant to this article was reported.

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