biology

Laser surgery

Laser surgery 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 Laser surgery rather than just read about it. In short: Laser surgery is a type of surgery that cuts tissue using a laser in contrast to using a scalpel. Soft-tissue laser surgery is used in a variety of applications in humans (general surgery, neurosurgery, ENT, dentistry, orthodontics, and oral and maxillofacial surgery) as well as veterinary surgical fields.

Key takeaways

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

Reference excerpt

Laser surgery is a type of surgery that cuts tissue using a laser in contrast to using a scalpel. Soft-tissue laser surgery is used in a variety of applications in humans (general surgery, neurosurgery, ENT, dentistry, orthodontics, and oral and maxillofacial surgery) as well as veterinary surgical fields. The primary uses of lasers in soft tissue surgery are to cut, ablate, vaporize, and coagulate. There are several different laser wavelengths used in soft tissue surgery. Different laser wavelengths and device settings (such as pulse duration and power) produce different effects on the tissue. Some commonly used lasers types in soft tissue surgery include erbium, diode, and CO2. Erbium lasers are excellent cutters, but provide minimal hemostasis. Diode lasers (hot tip) provide excellent hemostasis, but are slow cutters. CO2 lasers are both efficient at cutting and coagulating. Laser surgery is commonly used on the eye. Techniques used include LASIK, which is used to correct near and far-sightedness in vision, and photorefractive keratectomy, a procedure which permanently reshapes the cornea using an excimer laser to remove a small amount of the human tissue.

Effects Photochemical effect: clinically referred to as photodynamic therapy. Photosensitizer (photophrin II) is administered which is taken up by the tumor tissue and later irradiated by laser light resulting in highly toxic substances with resultant necrosis of the tumor. Photodynamic therapy is used in palliation of oesophageal and bronchial carcinoma and ablation of mucosal cancers of Gastrointestinal tract and urinary bladder. Photoablative effect: Used in eye surgeries like refractive surgery, band keratoplasty, and endartectomy of peripheral blood vessels. Photothermal effect: this property is used for endoscopic control of bleeding e.g. Bleeding peptic ulcers, oesophageal varices Photomechanical effect: used in intraluminal lithotripsy

Equipment

Surgical laser systems, sometimes called "laser scalpels", are differentiated not only by the wavelength, but also by the light delivery system: flexible fiber or articulated arm, as well as by other factors. Types of surgical lasers include carbon dioxide, argon, Nd:YAG laser, and potassium titanyl phosphate. CO2 lasers were the dominant soft-tissue surgical lasers as of 2010.

Applications

Dermatology and plastic surgery A range of lasers such as erbium, dye, Q switch lasers, and CO2 are used to treat various skin conditions including scars, vascular and pigmented lesions, and for photorejuvenation. The laser surgery for dermatology often bypasses the skin surface. The principle of laser surgery for dermatologic problems is based on SPTL (selective photothermolysis). The laser beam penetrates the skin until it encounters chromophore which absorbs the laser beam. After absorption of the laser beam, heat is generated to induce coagulation, necrosis of the targeted tissue, this results in the removal of unwanted tissue by laser surgery. Laser resurfacing is a technique in which covalent bonds of a material are dissolved by a laser, a technique invented by aesthetic plastic surgeon Thomas L. Roberts, III using CO2 lasers in the 1990s. Lasers are also used for laser-assisted lipectomy.

Eye surgery

Various types of laser surgery are used to treat refractive error. LASIK, in which a knife is used to cut a flap in the cornea, and a laser is used to reshape the layers underneath, is used to treat refractive error. IntraLASIK is a variant in which the flap is also cut with a laser. In photorefractive keratectomy (PRK, LASEK), the cornea is reshaped without first cutting a flap. In laser thermal keratoplasty, a ring of concentric burns is made in the cornea, which causes its surface to steepen, allowing better near vision. ReLEx SMILE is the latest advancement in laser vision correction technology. In SMILE surgery, ZEISS VisuMax femtosecond laser is used to make a small incision and to create a pre-calculated mini lens tissue (or lenticule) inside the cornea. Lasers are also used to treat non-refractive conditions, such as phototherapeutic keratectomy (PTK) in which opacities and surface irregularities are removed from the cornea and laser coagulation in which a laser is used to cauterize blood vessels in the eye, to treat various conditions. Lasers can be used to repair tears in the retina.

Endovascular surgery Laser endarterectomy is a technique in which an entire atheromatous plaque in the artery is excised. Other applications include laser assisted angioplasties and laser-assisted vascular anastomosis.

Foot and ankle surgery Lasers are used to treat several disorders in foot and ankle surgery. They are used to remove benign and malignant tumors, treat bunions, debride ulcers and burns, excise epidermal nevi, blue rubber bleb nevi, and keloids, and the removal of hypertrophic scars and tattoos. A carbon dioxide laser (CO2) is used in surgery to treat onychocryptosis (ingrown nails), onychauxis (club nails), onychogryposis (rams horn nail), and onychomycosis (fungus nail).

Gastro-intestinal tract Laser photoablation is can be used to treat Peptic ulcer disease and oesophageal varices. Laser surgery used in hemorrhoidectomy, and is a relatively popular and non-invasive method of hemorrhoid removal. Laser-assisted liver resections have been done using carbon dioxide and Nd:YAG lasers. Endoscopic laser lithotripsy is a safer modality compared to electrohydraulic lithotripsy. Lasers can be used to treat Coagulation of vascular malformations of stomach, duodenum, and colon. Laser can be effective in treating several forms of cancer: Lasers can be effectively used to treat early gastric cancers provided they are less than 4 cm and without lymph node involvement. Lasers are also used in treating oral submucous fibrosis. Palliative laser therapy is given in advanced oesophageal cancers with obstruction of lumen. Recanalisation of the lumen is done which allows the patient to resume a soft diet and maintain hydration. Ablative laser therapy is used in advanced colorectal cancers to relieve obstruction and to control bleeding. The ablation of liver tumors can be achieved by selective photovaporization of the tumor.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Laser surgery

Start with the simplest possible case. Write down what Laser surgery 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 Laser surgery 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 Laser surgery 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 Laser surgery

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

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

Frequently asked questions

What is Laser surgery in simple terms?

Why does Laser surgery 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 Laser surgery?

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 Laser surgery.