The most common symptomatic sequelae of cervical disk herniation (CDH) include cervicogenic headache, interscapular pain, and cervical radiculopathy/myelopathy. CDH is less commonly reported to have an association with a myriad of other symptoms including visual disturbances, diplopia, dysphagia, and transient vertigo1-6. There has been one published case of trigeminal sensory neuropathy brought about by CDH at the C3-C4 level7. The anatomic basis for this presentation stems from the fact that the trigeminal nerve was thought to extend no more distal than the C4 level of the spinal cord via the spinal trigeminal tract8.
The incidence of trigeminal neuropathy (TN) ranges from 4.5 to 28.9 per 100,000 per year and is statistically the most common of all cranial neuralgias1. Patients typically present with unilateral sensations in the somatosensory distribution of more than 1 branch of the trigeminal nerve9,10. The most common symptoms manifest as shock-like episodes of pain over the trigeminal distribution of the face V3 (lower lip, chin, posterior cheek, temple, external ear, mucosa of the lower part of the mouth, and anterior two-thirds of the tongue). Symptoms are often quick in onset and short in duration. The etiology of TN can be quite broad as it is reportedly associated with a myriad of conditions, e.g., traumatic, neoplastic, vascular, and autoimmune causes7.
Although there has been a report of CDH at the C3-C4 level causing left-sided TN, to the best of our knowledge there have been no reports of more caudal CDHs causing TN3. Herein, we report 2 cases with more than 1-year clinical follow-up and also mention a third case with identical presentation and clinical response. In each case, cervical stenosis resulting from a left-sided disk herniation between C5 and C7 caused TN and classic (dermatome appropriate) cervical radicular findings, which subsequently resolved with anterior decompression and fusion.
Each patient was informed that data concerning the case would be submitted for publication, and each patient agreed.
Case 1. A healthy 53-year-old woman presented with a 1-year history of progressive radicular pain and paresthesias radiating into the left anterior shoulder and scapular region, after a C6 pattern of radiation. Additionally, over the same period of time, she noted episodic severe shooting pain and paresthesias that radiated over the lower left side of her face in the distribution of the trigeminal nerve (V3 branch), which were reliably triggered with Spurling test. Bilateral upper extremity motor examination was 5/5, except for the left rotator cuff at 4/5. The left brachioradialis reflex (C6) was diminished when compared with the right. Sensation was intact to all bilateral upper extremity dermatomes. There was no evidence of vertebral artery compression symptoms, such as vertigo. She had limited cervical range of motion, most notably in left rotation and extension, which exacerbated her upper extremity and facial symptoms.
Three months from the onset of her symptoms, a magnetic resonance imaging (MRI) revealed severe left-sided foraminal stenosis at C5-C6 caused by disk herniation. MRI of the brain was normal. A decision to perform surgical decompression and fusion was made after failure of nonoperative measures. The standard Smith-Robinson technique was used, and the left nerve root was directly decompressed via diskectomy and resection of the uncovertebral joint. A 7-mm corticocancellous allograft was placed, and cervical plating was performed.
The patient reported immediate and complete resolution of her left upper extremity symptoms and atypical left-sided facial pain and paresthesias. At 1 year follow-up, the patient's examination demonstrated a negative Spurling test, 5/5 strength to bilateral upper extremities, with intact sensation and continued resolution of her facial paresthesia.
Case 2. A 68-year-old woman presented with a 1-year progressive history of radicular pain radiating into the left chest and upper extremity in a C6 and C7 distribution, with paresthesias along the radial forearm and hand. Additionally, the patient reported numbness and pain in the left side of her face in the trigeminal distribution (V3) but with a preserved corneal reflex. Surgical history is significant for a T10 to pelvis posterior fusion 3 years before the date of her clinical examination. Medical history is significant for atrial fibrillation treated with Plavix and daily 81 mg aspirin for chronic myeloid leukemia treated with Gleevac.
On examination, the patient demonstrated 5/5 strength throughout the bilateral upper and lower extremities, except for the left triceps and wrist extensors at 4/5. These symptoms, including facial paresthesias, were reproduced with a Spurling's maneuver and Valsalva stress. The left triceps reflex was absent when compared with 1+ on the right. MRI of the brain was normal. She underwent a left C5-C6 computed tomography-guided transforaminal epidural steroid injection, with excellent relief of her upper extremity symptoms and left-sided facial symptoms, which lasted 1 week.
MRI of the cervical spine revealed severe left-sided foraminal stenosis at C5-C6 secondary to an ossified disk herniation as well as a large, central C6-C7 disk herniation causing central stenosis. After failure of nonoperative measures with progressive symptoms, the patient elected to proceed with surgical decompression and stabilization. Anterior cervical diskectomy and fusions were performed at the C5-C6 and C6-C7 levels. A 6-mm allograft spacer was placed at the C5-C6 level, and a 7-mm allograft spacer was placed at the C6-C7 level. Cervical plating was performed. Postsurgical examination was normal.
As with case 1, this patient demonstrated immediate and complete symptomatic relief which has persisted through the most recent follow-up (>12 months).
Case 3. Case 3 is a 59-year-old woman with a 9-year history of left arm weakness and paresthesias. Six months before presentation, the patient began to experience episodic left-sided paresthesias in the C7 distribution, which were associated with new-onset paresthesias over the tongue. These episodic symptoms would occur in concert and were initially transient, lasting for an hour before they would abate. Cervical MRI demonstrated critical spinal stenosis at C5-C7, with a large disk protrusion/herniation at C5-C6 and to a lesser extent at C4-C5 and C6-C7, with resultant myelomalacia and cord compression. She developed progressive motor deficits and was referred for surgical assessment.
Both upper extremities demonstrated 3-4/5 strength in the triceps and wrist flexors. All remaining upper extremity myotomes demonstrated 5/5 strength. Sensation was intact to bilateral upper extremities. Hoffman sign was positive. Spurling test and L'Hermitte sign were negative.
The patient elected to proceed with operative intervention. Anterior exposure of the cervical spine was performed by an ENT surgeon, and the patient underwent C4-C5 anterior cervical diskectomy and C6 corpectomy with insertion of a 24-mm carbon fiber cage. Stabilization was achieved with C4-C7 anterior spinal instrumentation plating along with allograft bone grafting. The patient’s postoperative examination demonstrated no neurologic deficits. Symptomatic relief of the left arm radiculopathy and TN has persisted through the most recent follow-up (3 months).
At present, there is a paucity of documented case reports of CDHs causing TN-like symptoms. The case reports that do exist each demonstrate upper CDHs (C3-C4) with paresthesias and facial numbness in the trigeminal nerve distribution7,11. Barakos et al. presented a case study of trigeminal sensory neuropathy as a result of a cervical disk at the C3-C4 level directly impinging on the spinal trigeminal tract3. The pathophysiology was thought to be due to direct impingement as the trigeminal tract and nucleus extend to approximately the second to fourth cervical level4-6. To our knowledge, we present the only 3 patients to have had TN which abated after ACDF at the more caudal C5-C6 and C6-C7 levels.
The exact pathophysiology of cervicogenic TN is poorly understood, but it is postulated that there is a functional convergence of upper cervical and cranial trigeminal sensory pathways which allow for bidirectional referral of painful sensations between the cervical spine and trigeminal sensory receptive fields7,11. The trigeminocervical nucleus is thought to be the region of the upper cervical spinal cord where sensory nerve fibers of the descending tract of the trigeminal nerve interact with sensory fibers from the upper cervical roots. Although the trigeminal nucleus caudalis descends caudally as low as C3 or C4, afferent sensory signals ascend or descend up to 3 spinal cord segments in the dorsolateral tract before entering the spinal dorsal horn7,10. Theoretically, this can allow signals from spinal segments as low as C6 or C7 to have bidirectional stimuli.
To our knowledge, these 3 cases are the first to demonstrate a clear relationship between symptomatic TN and caudal CDHs. Given the fact that the 3 patients with this atypical finding presented to the same spine surgeon within 1 year of each other and that this presentation has only been acknowledged in the literature in 2 previous case reports, it would appear that this is an underreported or underappreciated phenomenon. The immediate and sustained response to surgical decompression suggests that it is important for physicians treating CDH to be aware that TN-like symptoms can be a manifestation of cervical radiculopathy.
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