science

Percutaneous nephrolithotomy

Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy rather than just read about it. In short: A percutaneous nephrolithotomy (PCNL, PCN, or PNL) is a minimally-invasive procedure to remove stones from the kidney by a small puncture wound (up to about 1 cm) through the skin. It is most suitable to remove stones over 2 cm in size or which are present near the pelvic region.

Key takeaways

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

Reference excerpt

A percutaneous nephrolithotomy (PCNL, PCN, or PNL) is a minimally-invasive procedure to remove stones from the kidney by a small puncture wound (up to about 1 cm) through the skin. It is most suitable to remove stones over 2 cm in size or which are present near the pelvic region. It is usually done under general anesthesia or spinal anesthesia. Since their development in 2000, PCNLs have become the standard treatment for complex and large kidney stones, and have largely obviated the need for open surgical procedures.

History Janak Desai developed the ultra-mini PCNL technique.

Procedure A retrograde pyelogram is first done to locate the stone in the kidney. Contrast is diluted to the ratio of 1:3. If the ureteric catheter is placed in the upper pole of the kidney, it should be pulled down so that the tip is inside the renal pelvis; this helps for proper filling of the renal calyces. The contrast is injected slowly to prevent extravasation. Fluoroscopy monitoring should be continuous so that the sequence of calyces filled can help to identify the position of posterior calyx. With a small (1 cm) incision in the loin, the PCN needle punctures the skin and is passed into the pelvis of the kidney. The position of the needle is guided and confirmed by fluoroscopic-guided puncture (FP), ultrasonography-guided puncture (UP), or a combination of both referred to as a combined fluoroscopic and ultrasonography-guided puncture (FUP). Fluoroscopy was the only available imaging technique before ultrasonography was introduced in the 1970s. If the puncture is not carefully done, other organs around the kidney may be damaged. A guide wire is passed through the needle into the pelvis. The needle is then withdrawn with the guide wire still inside the pelvis. Over the guide wire, the dilators are passed and a working sheath is introduced to gain access. The most common standard types of dilation are Amplatz dilation, metal telescopic dilation, and balloon dilation. A nephroscope is then passed inside and small stones taken out. In case the stone is big, it may first have to be crushed using ultrasound probes or via other means. The most difficult portion of the procedure is creating the tract between the kidney and the flank skin. Most of the time this is achieved by advancing a needle from the flank skin into the kidney, known as the antegrade technique. A retrograde technique has recently been updated wherein a thin wire is passed from inside the kidney to outside the flank with the aid of a flexible ureteroscope. This technique may reduce radiation exposure for both the patient and the surgeon.

Complications The following complications may take place:

Injury to the colon Injury to the lungs Injury to the renal blood vessels Urinary leak may persist for a few days Infection and sepsis Hydrothorax, if done through the 11th intercostal space Bleeding Death

Notes and references

Worked examples

Example 1 — a first encounter with Percutaneous nephrolithotomy

Start with the simplest possible case. Write down what Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy

In research: Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy 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: Percutaneous nephrolithotomy is common in secondary-school and first-year university syllabi. It links to neighbouring topics Urologic surgery, so understanding it makes those chapters shorter.
In everyday life: Look for Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Percutaneous nephrolithotomy in simple terms?

Why does Percutaneous nephrolithotomy 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 Percutaneous nephrolithotomy?

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 Percutaneous nephrolithotomy.