Overview

Definition

Posterior cord syndrome (PCS) is an incomplete spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord syndrome affecting the dorsal columns, the corticospinal tracts (CSTs), and descending autonomic tracts to the bladder.

Epidemiology

• Overall incidence: rare
• Least common of the spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord (SC) injury syndromes 

Etiology

• Demyelinating causes:
  • Multiple sclerosis Multiple Sclerosis Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis (primary progressive form)
  • Tabes dorsalis (neurosyphilis) 
• Infectious: AIDS-related myelopathy
• Mechanical:
  • Tumors
  • Seroma after spinal instrumentation
  • Cervical spondylosis/myelopathy
  • Atlantoaxial subluxation (with rheumatoid arthritis Rheumatoid arthritis Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). Rheumatoid Arthritis)
• Vascular/ischemic: posterior spinal artery occlusion
• Metabolic: subacute combined degeneration
  • Due to vitamin B₁₂ deficiency
  • Has also been seen with copper deficiency myeloneuropathy
• Hereditary neurodegenerative disorders:
  • Friedreich ataxia
  • Leukoencephalopathy with brain stem Brain Stem The brain stem is a stalk-like structure that connects the cerebrum with the spinal cord and consists of the midbrain, pons, and medulla oblongata. It also plays a critical role in the control of cardiovascular and respiratory function, consciousness, and the sleep-wake cycle. Brain Stem and SC involvement and lactate elevation (LBSL)
• Trauma

Pathophysiology

• Degeneration, mechanical compression, or ischemia → neurologic sequelae 
• Dorsal columns affected → bilateral loss of joint position and vibration sense:
  • Fasciculus gracilis
  • Fasciculus cuneatus
• Descending autonomic tracts affecting the parasympathetic system → urinary incontinence Urinary incontinence Urinary incontinence (UI) is involuntary loss of bladder control or unintentional voiding, which represents a hygienic or social problem to the patient. Urinary incontinence is a symptom, a sign, and a disorder. The 5 types of UI include stress, urge, mixed, overflow, and functional. Urinary Incontinence
• Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables degrees of corticospinal tract involvement → motor weakness, reflex dysfunction
• Spinothalamic tract preserved: intact pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain and temperature sensation

Clinical Presentation, Diagnosis, and Management

Understanding the structures affected by a posterior cord lesion is essential to their correlation with clinical signs and symptoms. Diagnosis of PCS is by clinical exam and diagnostic imaging. 

Clinical Presentation

• History:
  • Unsteady walking
  • Poor balance; falls
  • Paresthesias (tingling and “pins-and-needles” sensations)
  • Possible weakness or urinary incontinence Urinary incontinence Urinary incontinence (UI) is involuntary loss of bladder control or unintentional voiding, which represents a hygienic or social problem to the patient. Urinary incontinence is a symptom, a sign, and a disorder. The 5 types of UI include stress, urge, mixed, overflow, and functional. Urinary Incontinence
• Physical examination:
  • Findings are almost always bilateral.
  • Sensory deficits:
    • Loss of vibration sense
    • Loss of proprioception below the site of injury
  • If corticospinal tract fibers are affected:
    • Acute findings → weakness, muscle flaccidity, and hyporeflexia
    • Chronic findings → muscle hypertonia (spasticity), hyperreflexia, and positive Babinski sign (plantar reflex)
  • Preserved:
    • Pain and temperature sensation (retained spinothalamic function)
    • Light touch

Diagnosis

• Physical exam
• Lab testing:
  • Vitamin B₁₂ and copper levels
  • Rapid plasma reagin test for syphilis Syphilis Syphilis is a bacterial infection caused by the spirochete Treponema pallidum pallidum (T. p. pallidum), which is usually spread through sexual contact. Syphilis has 4 clinical stages: primary, secondary, latent, and tertiary. Syphilis
• Imaging:
  • X-ray of the cervical spine may show:
    • Degenerative spine disorders
    • Vertebral fractures
    • Atlantoaxial subluxation
  • CT/MRI to look for:
    • Demyelination
    • Impingement of the spinal canal
    • MRI may show hyperintensities in the posterior SC

Management

• Depends on the underlying cause
• Medical management:
  • Vitamin B₁₂ replacement for subacute combined degeneration
  • Penicillin for neurosyphilis
  • Treatment for multiple sclerosis if present
  • Treatment for cancer if present → inpatient SC rehabilitation → functional improvement and improved bowel/bladder continence
• Surgical laminectomy for spinal decompression if PSC PSC Primary sclerosing cholangitis (PSC) is an inflammatory disease that causes fibrosis and strictures of the bile ducts. The exact etiology is unknown, but there is a strong association with IBD. Patients typically present with an insidious onset of fatigue, pruritus, and jaundice, which can progress to cirrhosis and complications related to biliary obstruction. Primary Sclerosing Cholangitis is trauma-related.

Differential Diagnoses

• Anterior cord syndrome Anterior cord syndrome Anterior cord syndrome (ACS) is an incomplete cord syndrome predominantly affecting the anterior (ventral) …” of the spinal cord while sparing the dorsal columns. Anterior cord syndrome can be caused by occlusion of the anterior spinal artery or by trauma, which results in disc herniation and bone fragments disrupting the spinal cord. Anterior Cord Syndrome (ACS): incomplete cord syndrome to the anterior (ventral) ⅔ of the SC while sparing the dorsal columns. Anterior cord syndrome Anterior cord syndrome Anterior cord syndrome (ACS) is an incomplete cord syndrome predominantly affecting the anterior (ventral) …” of the spinal cord while sparing the dorsal columns. Anterior cord syndrome can be caused by occlusion of the anterior spinal artery or by trauma, which results in disc herniation and bone fragments disrupting the spinal cord. Anterior Cord Syndrome can be caused by an occlusion of the anterior spinal artery or trauma causing disc herniation and bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones fragments that disrupt the SC. Clinical manifestations are loss of motor and sensory function below the level of injury. Diagnosis of ACS is by clinical exam and neuroimaging with MRI. Management is directed at resolving the underlying cause. 
• Central cord syndrome Central Cord Syndrome Central cord syndrome (CCS) is a neurological syndrome caused by an injury to the center of the spinal cord, affecting the spinothalamic tracts ((STTs) sensory) and medial aspect of the corticospinal tracts ((CSTs) motor), most often due to trauma in patients with cervical spondylosis. Central Cord Syndrome (CCS): neurologic syndrome caused by an injury to the center of the SC, affecting the spinothalamic and corticospinal tracts, often caused by trauma in patients with cervical spondylosis. Clinical manifestations are motor deficits affecting the upper more than the lower limbs, variable sensory deficits below the level of injury, and bladder dysfunction. Diagnosis is made by exam and MRI. Management can be medical or surgical, depending on the severity of the injury.
• Brown-Séquard syndrome Brown-Séquard syndrome Brown-Séquard syndrome (BSS) is a rare neurologic injury that causes hemisection of the spinal cord, resulting in weakness and paralysis of one side of the body and sensory loss on the opposite side. Brown-Séquard Syndrome: hemisection of the SC secondary to injury, most commonly from penetrating trauma due to knife or bullet injuries. Other etiologies of Brown-Séquard syndrome Brown-Séquard syndrome Brown-Séquard syndrome (BSS) is a rare neurologic injury that causes hemisection of the spinal cord, resulting in weakness and paralysis of one side of the body and sensory loss on the opposite side. Brown-Séquard Syndrome include tumors, disc herniation, demyelination, and infarction. Clinical presentation includes weakness and paralysis of one side of the body and sensory loss on the opposite side. Diagnosis is by neurologic exam and with MRI. Management includes early treatment with high-dose steroids; other treatments are symptomatic and supportive.
• Conus medullaris syndrome and cauda equina syndrome: neurologic syndromes caused by compressive damage to the SC from T12 to L5, causing the disruption of the function of nerves below the point of compression. Diagnosis is made with MRI, and definitive management is prompt surgical decompression with laminectomy. 
• Spinal disc herniation Spinal disc herniation Spinal disk herniation (also known as herniated nucleus pulposus) describes the expulsion of the nucleus pulposus through a perforation in the annulus fibrosus of the intervertebral disk. Spinal disk herniation is an important pain syndrome with the potential for neurologic impairment. Spinal Disk Herniation (also known as herniated nucleus pulposus): expulsion of the nucleus pulposus through a perforation in the annulus fibrosus of the intervertebral disc. Spinal disc herniation Spinal disc herniation Spinal disk herniation (also known as herniated nucleus pulposus) describes the expulsion of the nucleus pulposus through a perforation in the annulus fibrosus of the intervertebral disk. Spinal disk herniation is an important pain syndrome with the potential for neurologic impairment. Spinal Disk Herniation is an important pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain syndrome with the potential for neurologic impairment and is most commonly caused by degenerative disc disease. Diagnosis is by clinical exam and MRI. Management ‌can be conservative with medications and physical therapy. Surgery is indicated for intractable pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain or myelopathy.