science

Implantable bulking agent

Implantable bulking agent 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 Implantable bulking agent rather than just read about it. In short: Implantable bulking agents are self-expanding solid prostheses which are implanted in the tissues around the anal canal. It is a surgical treatment for fecal incontinence and represents a newer evolution of the similar procedure which uses perianal injectable bulking agents.

Key takeaways

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Reference excerpt

Implantable bulking agents are self-expanding solid prostheses which are implanted in the tissues around the anal canal. It is a surgical treatment for fecal incontinence and represents a newer evolution of the similar procedure which uses perianal injectable bulking agents.

History The implantable bulking agents represent the most recent stage of development of a similar procedure which uses perianal injectable bulking agents. That procedure in turn was developed from use of injectable bulking agents in urology to treat urinary incontinence. Many different injectable materials have been used. The biggest problem with injectable materials is that they seem to have only a temporary effect. Over time, the material degrades and may migrate away from the injection site. For example, one study investigated the outcome and ultrasound appearance of 3 of the commonly used injectable bulking agents (Durasphere, PTQ, Solesta) after an average of 7 years. The researchers reported that typically about 14% of the original volume of material was still identifiable on ultrasound, and that complete disappearance of the materials on ultrasound was correlated with poorer clinical outcomes. Implantable bulking agents use multiple cylindrical HYEXPAN (polyacrylonitrile) implants. Marketed as "Gatekeeper" by Medtronic, Minneapolis, USA, it was first used to treat gastro-esophageal reflux disease. Production of the implant system was transferred to THD S.p.A., Correggio, Italy. Gatekeeper now has a CE marking, and was registered for the treatment of fecal incontinence in 2010. The first publication describing use of these implants in FI was in 2011. Several other publications appeared and the results were initially promising. In the original description, Gatekeeper used four self-expandable, solid, thin cylinders. Subsequently, six of the prostheses were used. An advancement of the procedure was described in 2016, marketed as "SphinKeeper". SphinKeeper uses 10 prostheses which are slightly thicker and longer compared to those used in the Gatekeeper implant system. One publication stated that new generation SphinKeeper implant system has replaced use of Gatekeeper, and that the use of 10 prostheses represents change in the paradigm of injectable and implantable bulking agents. SphinKeeper is a permanent implantable device rather than a bulking agent, and aims to create a kind of artificial neosphincter. Previous techniques aimed to simply augment the internal anal sphincter. The first systematic review on implantable bulking agents was published in 2022. However, no randomized placebo controlled trials have been published yet.

Material The implants are made of polyacrylonitrile (HYEXPAN). This material is inert, non-allergenic, non-immunogenic, nondegradable and noncarcinogenic. The material is hydrophilic, which allows the implants to slowly absorb water and change in dimensions, which occurs within 48 hours once they are implanted in the tissues. This polyacrylonitrile material is thought to meet the criteria for the "ideal bulking agent", and therefore may overcome the disadvantages of other bulking agents.

Indications Implantable bulking agents are indicated for passive fecal incontinence, caused by interior anal sphincter dysfunction or damage. The onset of incontinence should be at least 6 months ago. It has been recommended that this procedure should be attempted only if non-surgical options have failed (such as pharmacologic, behavioral, pelvic floor rehabilitation), and also if injectable bulking agents were unsuccessful. Researchers are investigating the use of GK and SK in patients with a wider range of causes of fecal incontinence. Contraindications have been suggested by different authors, and include:

Active perianal sepsis (infection) Inflammatory bowel diseases which involve the anorectal region (Crohn's disease, ulcerative colitis) Active treatment of anal, rectal or colon cancer Rectal bleeding of unknown cause Rectal prolapse Uncontrolled blood coagulation disorders Radiotherapy involving the pelvis Immunosuppression Pregnant patient or patient planning pregnancy in the next 12 months. Lesion involving >60° of the internal anal sphincter and/or >90° of the external anal sphincter, as shown on ultrasound. Severe anal scarring. Diabetes mellitus, pudendal neuropathy, and previous implantation of sacral nerve stimulation device are not contraindications to the use of implantable bulking agents.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Implantable bulking agent

Start with the simplest possible case. Write down what Implantable bulking agent 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 Implantable bulking agent 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 Implantable bulking agent 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 Implantable bulking agent

In research: Implantable bulking agent 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 Implantable bulking agent 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: Implantable bulking agent is common in secondary-school and first-year university syllabi. It links to neighbouring topics Colorectal surgery, Digestive system surgery, Gastroenterology, so understanding it makes those chapters shorter.
In everyday life: Look for Implantable bulking agent 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 Implantable bulking agent in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Implantable bulking agent 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.
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Frequently asked questions

What is Implantable bulking agent in simple terms?

Why does Implantable bulking agent 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 Implantable bulking agent?

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 Implantable bulking agent.