Cervical Spondylosis as a Potential Cause of Venous Hypertensive Myelopathy: A Case Report

Background

Cervical spondylotic myelopathy (CSM) is caused by degenerative changes in the intervertebral articular structure of the cervical spine, including disc herniation, osteophytes, and ossification of the posterior longitudinal ligament, resulting in a reduction in the diameter of the spinal canal and subsequent compression of the spinal cord [1,2]. The typical course of CSM is characterized by a gradual and progressive decline in neurological function. In general, the relatively rapid progression of neurological deterioration and symptoms of ascending myelitis in patients with CSM are rare in the absence of traumatic injury [1,2]. Venous hypertensive myelopathy (VHM) syndrome refers to a group of comprehensive symptoms caused by the obstruction of spinal drainage venous return or reversal of external venous blood into the spinal canal venous system, resulting in increased pressure on the spinal canal venous system and impaired spinal cord function [3,4]. Here, we describe a case of VHM, likely caused by disc herniation and spinal stenosis, resulting in progressive CSM, and discuss its potential pathophysiology.

Case Report

A 74-year-old male farmer with no notable medical history, including infections, arrived with the gradual development of pain in the neck and bilateral shoulders radiating to both upper limbs, accompanied by numbness and discomfort, with more severe symptoms on the right side. In the following session, the above symptoms repeatedly spontaneously existed and gradually worsened. Because resting on his right side caused numbness in his right arm and leg, he slept on his left side.

Two months after onset, he experienced weakness in his right face and upper and lower extremities, and gait disturbance with increased tone and stiffness, accompanied by numbness on the right side and a decreased pain sensation in the right face, along with poor bowel and urine control. These symptoms prompted the patient to seek medical care. Cervical magnetic resonance imaging (MRI) demonstrated C3 to C7 disc herniation with cervical degeneration, posterior spondylolisthesis (degree I) with spinal stenosis, and a relatively large high-intensity area in the spinal cord from the medulla oblongata to the T1 level on T2-weighted images (Figure 1A–1E). Lumbar puncture was not performed because of spinal stenosis. Paraneoplastic syndrome antibody, central nervous demyelination antibody, and visual-evoked potential test results were negative.

Acute inflammatory processes such as transverse myelitis or demyelinating disease were also considered. The patient was treated with methylprednisolone sodium succinate (80 mg daily for 8 days) and the dose was gradually reduced. However, the effect was not significant, and his symptoms worsened as hormone levels decreased. Over the next month, the symptoms described above worsened. He had significant difficulty in controlling bowel movements and urination. Physical examination revealed the following: muscle strength was 4/5 in the right upper limb and both lower-limb grades, and 5/5 in the left limb; muscular tension increased; and crude touch, pain, and warmth decreased in the right limb and face. Reflexes increased in the right limb. Hoffman’s sign was positive in the upper limb. Repeat cervical MRI demonstrated interval development of diffuse intramedullary increased T2 signal in the spinal cord, which gradually spread to the pons, with cord swelling and degeneration more apparent (Figure 1F–1J). After joint discussions of multidisciplinary treatment, differential diagnoses included compressive myelopathy, transverse myelitis, demyelinating disease, and, less likely, a tumor. The presence of cervical disc herniation causes cord edema, which leads to progressive neurologic impairment. Therefore, surgery was recommended. The patient agreed to undergo surgical decompression. Posterior C3–C6 expansive open-door cervical laminoplasty with lateral mass screw insertion and C2 and C7 decompression surgeries were performed. The postsurgical and surgery courses went smoothly. Postoperative imaging is shown in Figure 2A–2D.

One week after the surgery, his gait disturbance considerably improved, and bowel and bladder functions returned. Physical examination revealed the following: muscle strength was 4/5 in the right upper limb, 5/5 in the left limb and both lower-limb grades; muscular tension relatively increased in the right upper limb; and crude touch, pain, and warmth in the right limb and face recovered compared with the preoperative situation. Hoffman’s sign was positive in the upper limb. Repeat cervical MRI revealed significant improvement in spinal cord edema and degeneration (Figure 3A–3D).

One month after the surgery, the patient’s symptoms had improved. Although his right hand’s partial loss of dexterity persisted, daily life was not affected, and follow-up cervical MRI results confirmed improvement (Figure 3E–3H).

Discussion

We present a very uncommon case of CSM with relatively rapid neurologic deterioration and aberrant growth of the high-signal intensity area on T2-weighted MRI, which progressed to the pons.

In this case, the relatively rapid neurological deterioration and enlargement of the T2 high-intensity region indicated the possibility of transverse myelitis, neuromyelitis optica, and multiple sclerosis, rather than CSM on admission. Intramedullary high-signal lesions associated with spinal cord edema on T2WI are rare in patients with CSM [5,6]. However, the patient’s medical history, disease course, negative laboratory results, evoked potential examination, and poor effect of hormone therapy indicated a low probability of systemic transverse myelitis and inflammatory demyelinating disease.

Therefore, compressive myelopathy was suspected. Decompression surgery was performed after the patient agreed. Patients with CSM have significantly reduced spinal canal reserve space, often with multi-segment spinal canal stenosis and spinal cord compression. Mild external forces can lead to severe spinal cord injury. Anterior surgery for such patients often involves incomplete decompression and higher surgical risk, especially in patients with 3 or more vertebral bodies involved. Therefore, posterior surgery is the most commonly chosen option, which can achieve maximum decompression and effectively preserve most of the bone structure of the cervical spine.

Postoperatively, our patient’s gait disturbance, muscle weakness, and bowel and bladder functions significantly improved. Repeat MRI after surgery revealed a significantly smaller local T2 high-intensity area. Improvements in the clinical signs and imaging findings strongly suggested that the spinal cord injury was most likely caused by physical compression of the spinal cord. Most spinal cord pathologies in CSM occur through direct cord compression [1]. However, in this case, the spinal cord injury showed abnormal expansion of the high-signal intensity area on T2- weighted MRI and could gradually rise to the pons. This feature requires consideration of the pathological mechanism of the injury caused by indirect compression of the spinal cord.

Slipped disc and cervical canal stenosis resulting in arterial compression were excluded because spinal large artery compression syndrome typically manifests with sudden onset, similar to a stroke, with clinical manifestations reaching their peak within minutes, hours, or a few days [7]. Chronic ischemia caused by small blood vessel compression is relatively limited and is not prone to progressive deterioration [8]. Therefore, we hypothesized that spinal vein drainage disorders result in VHM, causing spinal cord edema, necrosis, and dysfunction. The following reasons support this hypothesis: (1) T2-weighted MRI’s high-signal intensity region far exceeded the spinal cord compression area and gradually expended; (2) The level of neurological impairment did not match the T2 high area; (3) Changes in posture are related to the ease or worsening of symptoms; (4) Flow gaps on the dorsal surface of the upper cervical cord on T2-weighted MRI; and (5) Significant and rapid relief of symptoms and imaging findings after cervical surgical decompression.

VHM is generally considered to be intimately associated to spinal vascular malformations, including dural arteriovenous fistulas and spinal cord arteriovenous malformations. Nonetheless, a few other causes of VHM have been identified [3,4]. In our case, VHM was caused by disc herniation and spinal stenosis, resulting in progressive myelopathy, which is rare. The reversible manifestation of both neurological deterioration and imaging abnormalities is a clinical characteristic of VHM [3]. In terms of the pathological mechanism, we suggest that venous return was blocked, including the anterior and posterior medullary veins, vertebral vein, and other venous plexuses that were compressed by the cervical vertebra. Disturbances in venous circulation result in local venous hypertension at the affected level, eventually leading to VHM [3,4]. As the medullary veins and vertebral plexus have valves [9], venous pressure gradually spreads to the intracranial area and eventually involves the brainstem.

A continuous increase in the VHM pressure causes intramedullary edema, ischemia, and necrosis, which results in severe permanent paralysis and irreversible spinal damage [3,10]. Despite the completion of decompression surgery and improvement in neurological function, the function was not at baseline.

Conclusions

This case report shows that spondylotic cord compression can result in VHM, leading to spinal cord injury. When encountering clinical cases similar to this one, VHM should be included in the differential diagnosis by physicians. Therefore, an accurate diagnosis and timely surgery are essential.