science

Posterior spinal artery syndrome

Posterior spinal artery syndrome is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Posterior spinal artery syndrome rather than just read about it. In short: Posterior spinal artery syndrome (PSAS), also known as posterior spinal cord syndrome or posterior cord syndrome, is a type of incomplete spinal cord injury. PSAS is the least commonly occurring of the six clinical spinal cord injury syndromes, with an incidence rate of less than 1%.

Key takeaways

Posterior spinal artery syndrome belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Posterior spinal artery syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Posterior spinal artery syndrome from memory before moving on to harder problems.

Reference excerpt

Posterior spinal artery syndrome (PSAS), also known as posterior spinal cord syndrome or posterior cord syndrome, is a type of incomplete spinal cord injury. PSAS is the least commonly occurring of the six clinical spinal cord injury syndromes, with an incidence rate of less than 1%. PSAS originates from an infarct in the posterior spinal artery and is caused by lesions on the posterior portion of the spinal cord, specifically the posterior column, posterior horn, and posterolateral region of the lateral column. These lesions can be caused by trauma to the neck, occlusion of the spinal artery, tumors, disc compression, vitamin B12 deficiency, syphilis, or multiple sclerosis. Despite these numerous pathological pathways, the result is an interruption in transmission of sensory information and motor commands from the brain to the periphery.

Causes Trauma to the spinal cord, such as neck hyperflexion injuries, are often the result of car accidents or sports-related injuries. In such injuries, posterior dislocations and extensions occur without the rupture of ligaments. This blunt trauma may be further complicated with subsequent disc compression. In addition to these complications, transient ischemic attacks could occur in the spinal cord during spinal artery occlusion. Common pathological sources of PSAS include Friedreich's Ataxia, an autosomal-recessive inherited disease, and tumors such as astrocytoma, ependymoma, meningioma, neurofibroma, sarcoma, and schwannoma.

Cobalamin, commonly known as vitamin B12, plays a crucial role in the synthesis and maintenance of myelin in neurons found in the spinal cord. A deficiency of this essential vitamin results in demyelination, a deterioration of the axon's layer of insulation causing interrupted signal transmission, with a currently unknown specificity to the posterior region. PSAS may develop with the failure to treat syphilis. Symptoms typically appear during the tertiary phase of the disease, between twenty and thirty years after the initial syphilis infection. Failure to treat syphilis leads to progressive degeneration of the nerve roots and posterior columns. The bacteria Treponema pallidum that causes syphilis results in locomotor ataxia and tabes dorsalis. Further complications from tabes dorsalis include optic nerve damage, blindness, shooting pains, urinary incontinence, and degeneration of the joints. In most cases, lesions present bilaterally. However, in rare cases, lesions have been seen unilaterally. Moreover, general symptoms of posterior spinal artery infarcts include ipsilateral loss of proprioceptive sensation, fine touch, pressure, and vibration below the lesion; deep tendon areflexia; and in severe circumstances, complete paralysis below the portion of the spinal cord affected.

Diagnosis Complete spinal imaging, X-rays, computed tomography (CT), or magnetic resonance imaging (MRI) can be used to identify infarctions on the dorsal columns. Imaging alone is often inconclusive and does not present a full analysis of the affected columns. Clinical history, blood and cerebral spinal fluid (CSF) tests can also be used to make a full diagnosis.

Treatment Treatment for posterior spinal artery syndrome depends on the causes and symptoms, as well as the source of the infarction. The main goal of treatment is to stabilize the spine. Possible treatments include airway adjuncts; the use of ventilators; full spinal precautions and immobilization; and injections of dopamine. While there is no definitive cure for posterior cord syndrome, treatment and supportive care can be provided based on the patient's symptoms. Therapy and rehabilitative care including walking aids, physical, occupational, and psychotherapy can help ease the symptoms associated with PSAS. Acute therapy can include intensive medical care and analgesia. Corticosteroids are used to reduce any inflammation or swelling. Bracing or surgical repair can be done to stabilize the spinal fracture.

Research

It has been difficult to make any breakthroughs in diagnosis and/or treatment of PSAS as symptoms are not specific in nature and can vary based on the exact location of spinal cord lesions. In addition, the demographics of patients with PSAS are widespread as the onset of symptoms typically follows a traumatic event. Additionally, research has suffered setbacks because PSAS is rare with few documented cases, unlike anterior spinal artery syndrome. However, ongoing research has helped in differentiating PSAS from other brain injuries. Therefore, better therapies for PSAS treatment can be developed. For instance, one study suggests that a tissue plasminogen activator (tPA) therapy intervention, commonly used in stroke patients, may aid in treating patients with symptoms of PSAS.

References

External links

Illustrations

Worked examples

Example 1 — a first encounter with Posterior spinal artery syndrome

Start with the simplest possible case. Write down what Posterior spinal artery syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Posterior spinal artery syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Posterior spinal artery syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Posterior spinal artery syndrome

In research: Posterior spinal artery syndrome appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Posterior spinal artery syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Posterior spinal artery syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Rare syndromes, Spinal cord injury, Syndromes affecting the nervous system, so understanding it makes those chapters shorter.
In everyday life: Look for Posterior spinal artery syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Posterior spinal artery syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Posterior spinal artery syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Posterior spinal artery syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Posterior spinal artery syndrome in simple terms?

Why does Posterior spinal artery syndrome matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Posterior spinal artery syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Posterior spinal artery syndrome.