biology

Lumbar–peritoneal shunt

Lumbar–peritoneal shunt is a biology 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 Lumbar–peritoneal shunt rather than just read about it. In short: A lumbar–peritoneal shunt is a technique to channelise the cerebrospinal fluid (CSF) from the lumbar thecal sac into the peritoneal cavity. Overview A shunt is described as a tube, catheter or "surgically created anastomosis" and is designed to bypass or redirect bodily fluids from one point in the body to another.

Key takeaways

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

Reference excerpt

A lumbar–peritoneal shunt is a technique to channelise the cerebrospinal fluid (CSF) from the lumbar thecal sac into the peritoneal cavity.

Overview A shunt is described as a tube, catheter or "surgically created anastomosis" and is designed to bypass or redirect bodily fluids from one point in the body to another. Lumbar–peritoneal shunts are used in neurological disorders, in cases of chronic increased intracranial pressure to drain excess cerebrospinal fluid (CSF) from the Subarachnoid cavity associated with such conditions as hydrocephalus and Benign intracranial hypertension (BIH) also known as idiopathic intracranial hypertension (IIH) and pseudotumor cerebri (PTC), idiopathic intracranial hypertension is the preferred name for the condition. There are various categories of medical shunts and there are two main categories of shunt used in the treatment of chronic increased intracranial pressure due to cerebrospinal fluid (CSF), they are cerebral shunts and lumbar shunts (extracranial shunts). Below is a list of the various types of the above two categories of shunts:

Cerebral shunts Ventriculo–peritoneal shunt (VP shunt) Ventriculo–atrial shunt (VA shunt) Ventriculo–pleural shunt (VPL shunt)

Lumbar shunts Lumbar–peritoneal shunt (LP shunt) Lumbar subcutaneous shunt (LS shunt)

Composition of shunts Each of the types of shunts listed above can be composed of a tube or catheter and various types of valves, although they can just be composed of the tubing or catheter. Below is a list of valves that are used in lumbar–peritoneal shunts (LP shunts) and Cerebral shunts (for a more detailed list of the types of valves see type of valves):

Delta Medium Pressure Cylindrical Nulsen and Spitz Anti-Siphon Sigma The composition of a lumbar–peritoneal shunt is dependent on the Neurosurgeon performing the operation, there are no guidelines determining what the composition of the lumbar–peritoneal shunt should be for different types of cases. The composition of the lumbar–peritoneal shunt can affect how well the patient will get on with the shunt and whether or not they may need revisions in the future, although this is not the only determining factor in whether or not a revision will be necessary.

Placement The lumbar–peritoneal shunt is inserted between two of the lumbar vertebrae of the spine into the subarachnoid space. The subarachnoid space is a spongy tissue-filled cavity that surrounds the brain and spinal cord, where cerebrospinal fluid (CSF) is contained. The shunt is placed under the skin, continues around the oblique muscles on one side of the body, and terminates at the peritoneal cavity, a cavity in the abdomen area of the body. Once in place the lumbar–peritoneal shunt is used to drain the excess cerebrospinal fluid from the brain via the subarachnoid space and transport it to the peritoneal cavity, where it is eventually absorbed by the organs and passed out of the body during urination. The operation is performed under general anesthetic by a neurosurgeon and usually takes a couple of hours. Patients with lumbar–peritoneal shunts are left with two scars; a vertical scar down part of the lumbar of the spine, and a horizontal scar across the upper abdomen. A lumbar–peritoneal shunt is expected to remain in situ for the lifespan of the patient unless revisions or relocation of the shunt is required. In some cases the shunt has been removed completely; however, this is very rare as it is difficult to determine when a patient's condition has changed to enable them to be independent of the shunt and relapse of the condition can occur requiring the patient to undergo surgery for the placement of a shunt again. A lumbar subcutaneous shunt (LS shunt) differs from these types of shunt in that the cerebrospinal fluid drains into the potential space immediately under the skin. A narrow tube is inserted into the subarachnoid space in the lumbar part of the back during a lumbar puncture. It is then fed under the skin to a site where it can drain fluid, usually in the flank.

Shunt revisions The revision of a shunt means to replace or make adjustments to all or part of the shunt, this also means that the location of the shunt may be changed therefore changing the category or type of shunt a patient has. For some patients with shunts, a revision or multiple revisions to the shunt may be required. This can be something minor, such as adjusting the setting on a valve to change the flow level through the valve to replacing a substantial length of the shunt, or even replacing the entire shunt or relocating the shunt route to a different part of the body. For example, it may be required for a patient with a lumbar–peritoneal shunt, if multiple revisions are required or overdrainage is occurring, to have it replaced with a ventriculo–peritoneal shunt (VP shunt). Shunt revisions are required due to the following complications:

Over drainage Under drainage Infection Blockage or obstruction

References

Worked examples

Example 1 — a first encounter with Lumbar–peritoneal shunt

Start with the simplest possible case. Write down what Lumbar–peritoneal shunt claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Lumbar–peritoneal shunt 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 Lumbar–peritoneal shunt 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 Lumbar–peritoneal shunt

In research: Lumbar–peritoneal shunt appears in biology 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 Lumbar–peritoneal shunt 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: Lumbar–peritoneal shunt is common in secondary-school and first-year university syllabi. It links to neighbouring topics Neurology procedures, so understanding it makes those chapters shorter.
In everyday life: Look for Lumbar–peritoneal shunt 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 Lumbar–peritoneal shunt in 20 minutes

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Close the page and write down what Lumbar–peritoneal shunt means in your own words.
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Frequently asked questions

What is Lumbar–peritoneal shunt in simple terms?

A lumbar–peritoneal shunt is a technique to channelise the cerebrospinal fluid (CSF) from the lumbar thecal sac into the peritoneal cavity. Overview A shunt is described as a tube, catheter or "surgically created anastomosis" and is designed to bypass or redirect bodily fluids from one point in the…

Why does Lumbar–peritoneal shunt matter?

Because it connects several biology 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 Lumbar–peritoneal shunt?

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 Lumbar–peritoneal shunt.