Brown-Sequard syndrome (BSS) has been reported in patients with various spinal pathologies, including spinal traumatic injuries, spinal cord neoplasms, epidural hematomas and spinal cord ischemia. Pure BSS caused by cervical disc herniation is very rare.
We report a rare case of cervical disc herniation presenting as BSS associated with Horner syndrome (HS), which has not been reported up to now. A prompt diagnosis by magnetic resonance imaging (MRI), followed by spinal cord decompression was performed. A postoperative rapid improvement of the neurological deficits was observed.
We review the literature and discuss the functional anatomy of spinal cord of BSS combined with HS. And it is important that clinicians be aware that a MRI of spinal cord is needed for those patients with a thoracic sensory level, and that a thoracic sensory level might not only depend on the level of spinal cord injury but also on the stage of evolution of the lesion.
Brown-Sequard syndrome (BSS) features ipsilateral upper motor neuron paralysis (hemiplegia) resulting from corticospinal tract interruption and ipsilateral loss of proprioception due to posterior columns’ impairment, combined with contralateral pain and temperature sensation deficits as a result of spinothalamic tract dysfunction. However, pure BSS is an uncommon occurrence with relatively few studies, and most patients present with an incomplete form of this condition,1 with or without some additional features, which were called Brown-Sequard-plus syndrome.2
In 1849, BSS was first reported as a clinical constellation after a traumatic transverse of the spinal cord from a knife.3 BSS is most commonly seen in the setting of spinal traumatic injuries or spinal cord neoplasms, epidural hematomas.1,
A 51-year-old woman presented with a 5-day history of progressive right hemiparesis and was admitted to difficulty with walking, as well as numbness in the lower trunk and limbs on the left side, associated with mild neck pain for 2 years. There was no history of trauma, arthritis. On admission, neurological examination revealed motor weakness and spasticity of the right side of the body (Manual Muscle Test 3/5) and diminished sensation to pain and temperature on the left side below the T6 dermatome, which were consistent with BSS. The patellar-tendon reflexes were bilaterally hyperactive. Positive Babinski signs were present bilaterally. She had reduced neck mobility, combined with a right HS, including slight lid drop, and the right pupil smaller than the left, was also noticed (Figure 1). There was no loss of deep sensation on both sides. Moreover, there were no radicular symptoms and no bladder or bowel dysfunction.
Magnetic resonance imaging of the cervical spine revealed a large central and right-sided extradural C5–6 disc herniation, almost obliterating the right side of the spinal cord, and a small central and extradural C3–4 disc herniation was observed. The underlying cord showed high signal intensity on T2-weighted images (Figure 2).
The patient underwent anterior cervical corpectomy (C5) and reconstruction using titanium mesh cages, associated with cervical immobilization using rigid cervical collar for 8 weeks postoperatively. The patient recovered from surgery with no complications. The neck pain disappeared almost completely within 6 weeks after the surgery. After 2 months from the operation, miosis and ptosis were dramatically recovered (Figure 1). At the 8 month follow-up, the patient had significant improvement with 5/5 strength in right upper extremity and 4/5 in right lower extremity. The numbness had completely resolved, whereas there was some residual lower-limb hypalgesia in left side.
Cervical disc herniation is a common neurosurgical problem that is encountered in routine neurosurgical practice. Cervical disc herniation is a rare cause of BSS. In 1928, Stookey first reported a herniated cervical disc as a etiology of BSS.5 We found 58 cases reported in the literature,4 with our cases increasing the number to 59. The frequency of this syndrome has been reported to be 2.6% and 0.21% by Jomin et al and Kim et al, respectively.6 A review of the literature associated with BSS caused by herniated cervical disc indicates that C5–C6 is the most vulnerable in discogenic BSS,3,4,6 and that most cases with no or insignificant radicular symptoms resulting from the neural compression seen in most patients of which was primarily paracentral herniation on the spinal cord itself and not the nerve root.7 In addition, most cases of discogenic BSS were related to extradural herniation, which seemed to be associated with complete neurological recovery more often compared with these intradural herniation, either an anterior approach or a posterior surgery.3,4,6,7
Presenting syndromes of spinal cord injury are based on the functional anatomy, and a basic knowledge of spinal cord anatomy is essential for interpretation of clinical signs and symptoms and understanding of pathologic processes involving the spinal cord.8,9
Transverse injury of hemicord disrupts descending corticospinal tract has already crossed in the pyramidal decussations, resulting in upper motor neuron paralysis in the ipsilateral side below the level of the lesion,1,3,
Typical HS is characterized by the classic triad of ipsilateral eyelid ptosis and miosis, combined with ipsilateral anhydrosis.12 HS is often classified into central, preganglionic and postganglionic types, based on the interruption localization of the oculosympathetic pathway.13,14 Central HS is uncommon, which usually is a part of brain disorders, including brain stem ischemia, brain tumors, and it is often associated with other neurological findings.12,13,14 Postganglionic HS may often relate to the lesions involving the internal carotid artery, skull base or cavernous sinus/ and orbital apex.12,13,14 The most frequent causes of preganglionic HS are tumor and trauma, which is the most common variety seen in clinical practice. However, cervical herniated disc caused HS were very rare; we found only 2 cases reported in the literature, including ours.12,13,14 Spinal cord compression relates to cervical disc herniation at C4–5 or C5–6 levels producing an insult to the sympathetic pathway, which may be a possible cause of HS in our case.12,13,14
The procedure for the treatment of cervical disc herniation includes analgesics, cervical soft collar and surgical treatment.15 However, mounting data indicated that a prompt surgical decompression should be recommended for cases with progressive neurologic deterioration.15 The treatment decision of anterior or posterior surgical approaches is based on multiple factors, including the anatomical location of the herniated disc, the longitudinal extent of disease, the alignment of the spinal column and the dimensions of the spinal canal.10,15 In our case, an anterior cervical corpectomy with fusion and instrumentation was performed. At final follow-up, our patient got a good functional recovery, except for the residual hypalgesia, which was consistent with that in previous study by Kohno M et al.16
Cervical disc herniation as a very rare cause of BSS and HS, especially for those patients with BSS associated with HS, an accurate diagnosis and early surgical decompression of the spinal cord, is the most important for patients to get an improvement in neurological function. And also it is important that clinicians should be aware that a magnetic resonance imaging of spinal cord (cervicle and thoracic level) is needed for those patients with a thoracic sensory level, and that a thoracic sensory level might not only depend on the level of spinal cord injury (cervical or thoracic) but also on the stage of evolution of the lesion, which mostly attributes to the damaged lamination of spinothalamic tracts in transverse section, as well as, a thoracic sensory level may be a false localizing sign in cervical spinal cord sometime, especially for those patients with normal findings on magnetic resonance imaging of thoracic spinal cord.
This work was supported by the Orthopedic Institute of Changzheng Hospital.