science

Non-lifting sign

Non-lifting sign 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 Non-lifting sign rather than just read about it. In short: The non-lifting sign is a finding on endoscopic examination that provides information on the suitability of large flat or sessile colorectal polyps for polypectomy by endoscopic mucosal resection (EMR). When fluid is injected under a polyp in preparation for endoscopic mucosal resection, some polyps do not "lift", indicating that the polyp is not separating from the submucosa.

Key takeaways

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

Reference excerpt

The non-lifting sign is a finding on endoscopic examination that provides information on the suitability of large flat or sessile colorectal polyps for polypectomy by endoscopic mucosal resection (EMR). When fluid is injected under a polyp in preparation for endoscopic mucosal resection, some polyps do not "lift", indicating that the polyp is not separating from the submucosa. This makes polypectomy more technically difficult, and increases the risk of intestinal perforation if polypectomy is then attempted. It is also thought to be indicative of an early colorectal cancer that has invaded the submucosa significantly (sm3 – invasion down to the lower one-third of the submucosa), which would make surgical removal of the tumour preferable to allow complete removal of the cancer. Consequently, the non-lifting sign is generally considered to be a contraindication to performing endoscopic mucosal resection.

History The non-lifting sign was first described in 1994 by Yoshiharu Uno and Akihiro Munakata of the Hirosaki University School of Medicine, Japan. In 1999 the same team showed that the presence of a non-lifting sign correlated with the depth of invasion of the submucosa by early colorectal cancers that were being considered for endoscopic resection. The tumours which did lift when fluid was injected were found to be less invasive than those that did not (sm1 or sm2 - invasion confined to the upper two-thirds of the submucosa, with at least 1mm of uninvolved submucosa underneath). It is thought that the non-lifting sign is due to fibrosis around the tumour causing tethering of the tumour to the muscularis mucosae. Subsequent research suggested that the non-lifting sign is less accurate in determining depth of tumour invasion than the assessment of tumours by the endoscopist, but still suggests that the presence of the sign makes endoscopic resection technically difficult. However, more recently it has been found that fibrosis may be caused when a tumour is biopsied before endoscopic mucosal resection is attempted, which leads to a false positive non-lifting sign and therefore reduces the apparent accuracy of the sign. The authors, therefore, recommended avoidance of biopsy of the lesions if EMR is to be attempted, and if biopsies have been taken the time before EMR is attempted should be minimised.

References

Worked examples

Example 1 — a first encounter with Non-lifting sign

Start with the simplest possible case. Write down what Non-lifting sign 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 Non-lifting sign 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 Non-lifting sign 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 Non-lifting sign

In research: Non-lifting sign 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 Non-lifting sign 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: Non-lifting sign is common in secondary-school and first-year university syllabi. It links to neighbouring topics Diagnostic gastroenterology, Endoscopy, Medical signs, so understanding it makes those chapters shorter.
In everyday life: Look for Non-lifting sign 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Non-lifting sign in 20 minutes

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

Frequently asked questions

What is Non-lifting sign in simple terms?

Why does Non-lifting sign 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 Non-lifting sign?

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 Non-lifting sign.