Laser Surgery: Principles and Safety

<p>It is reduced to one-fourth. (B)</p> Signup and view all the answers

<p>In watts. (C)</p> Signup and view all the answers

<p>To focus the laser beam. (C)</p> Signup and view all the answers

<p>Helium-neon beam. (A)</p> Signup and view all the answers

<p>Protein denaturation (C)</p> Signup and view all the answers

<p>It determines the tissue injury depth and vaporization. (B)</p> Signup and view all the answers

<p>100 µm (C)</p> Signup and view all the answers

<p>Minimal operative trauma and vascular seal (A)</p> Signup and view all the answers

<p>Weaker than scalpel incisions (D)</p> Signup and view all the answers

<p>They are sealed (B)</p> Signup and view all the answers

<p>It increases in temperature (A)</p> Signup and view all the answers

<p>300 to 500 µm (C)</p> Signup and view all the answers

<p>Tissue surface appears paler (B)</p> Signup and view all the answers

<p>They are always turned on, providing stable intensity. (B)</p> Signup and view all the answers

<p>Lower postoperative pain and complications. (B)</p> Signup and view all the answers

<p>Larger dispersion of thermal effect. (B)</p> Signup and view all the answers

<p>Large tissue resections. (A)</p> Signup and view all the answers

<p>They have a very short pulse duration. (B)</p> Signup and view all the answers

<p>It has a more ablative action. (B)</p> Signup and view all the answers

<p>It controls the laser's exposure time. (D)</p> Signup and view all the answers

<p>Less precision in cutting. (D)</p> Signup and view all the answers

<p>Bone (A)</p> Signup and view all the answers

<p>To vaporize the target tissue (C)</p> Signup and view all the answers

<p>To initiate absorption of the laser energy (C)</p> Signup and view all the answers

<p>Port wine stains (A)</p> Signup and view all the answers

<p>Argon laser (C)</p> Signup and view all the answers

<p>Increases its power density (D)</p> Signup and view all the answers

<p>Minimizing laser energy delivered (D)</p> Signup and view all the answers

<p>Extrinsic compression of the airway (C)</p> Signup and view all the answers

<p>A series of irregular spikes (B)</p> Signup and view all the answers

<p>Less thermal damage to surrounding tissue (D)</p> Signup and view all the answers

<p>The wavelength is too long to transmit through optical fibers (B)</p> Signup and view all the answers

<p>To stabilize the population inversion (D)</p> Signup and view all the answers

<p>It can control spiking to produce very short laser pulses (C)</p> Signup and view all the answers

<p>Less than 2 µm (C)</p> Signup and view all the answers

<p>It is extremely short, resulting in minimal coagulation (C)</p> Signup and view all the answers

<p>The state where more atoms are in an excited state than in a ground state (D)</p> Signup and view all the answers

<p>Treating melanocytic nevi (B)</p> Signup and view all the answers

<p>It can be applied through a flexible endoscope. (D)</p> Signup and view all the answers

<p>The intensity of the laser and exposure time (C)</p> Signup and view all the answers

<p>It shortens the pulse duration. (A)</p> Signup and view all the answers

<p>By the distance between mirrors in the cavity (A)</p> Signup and view all the answers

<p>Intensity of the laser (D)</p> Signup and view all the answers

<p>A substance that absorbs light at specific wavelengths (C)</p> Signup and view all the answers

<p>Shorter pulses of light (A)</p> Signup and view all the answers

The area of the laser beam's cross-section, calculated as πr² or πd²/4, where 'r' is the beam radius and 'd' is the beam diameter.

Irradiance, or power per unit area, is inversely proportional to the square of the beam diameter. Doubling the diameter reduces irradiance to one-fourth.

The rate at which laser energy is delivered, measured in watts.

The area of the laser beam's focal point, measured in square millimeters or square centimeters.

The duration for which the laser energy is applied, measured in seconds.

The most fundamental laser beam mode, characterized by a circular cross-section.

Physicians control power (watts), spot size (area), and exposure time (seconds) of surgical lasers.

The distribution of the laser energy across the focal spot, determining how tissue is injured/vaporized.

Shorter light wavelengths are scattered more by tissue than longer wavelengths.

Radiant energy can be reflected or transmitted through tissue, affecting its properties.

High-energy laser beams cause a localized zone of tissue death.

The zone of tissue death surrounding a laser incision is about 100 µm wide.

Following thermal necrosis, a zone of tissue repair and conductivity is present, 300 to 500 µm wide.

Laser incisions often exhibit minimal postoperative edema compared to scalpel incisions.

Some studies suggest that CO2 laser incisions might lead to impaired wound healing compared to scalpel incisions.

At temperatures between 60°C and 65°C, proteins in tissue begin to break down.

Argon laser light is absorbed by hemoglobin and pigmented tissues, causing a thermal reaction in the target tissue.

A procedure using an argon laser to perform surgery on the stapes.

High power density laser beams can vaporize tissue.

Minimizing laser energy to the vascular cutaneous lesion reduces scarring tendencies in the overlying skin.

Laser bronchoscopy procedure for airway conditions.

Careful selection of patients is crucial in laser procedures to avoid possible complications.

Tissue color influences absorption of laser energy; white tissues reflect more.

A condition where the stapes bone is affected, requiring a stapedotomy procedure.

Lasers that are always on, with a consistent intensity.

Lasers that turn on and off in short bursts.

A type of laser, often used as an alternative to CO2 lasers in surgery.

A CO2 laser that's delivered through a glass fiber.

Laser type that pulses in bursts, lasting from milliseconds to hundreds of milliseconds.

The stopping of bleeding.

A surgical procedure (likely a type of resection)

A surgical technique that uses heat to stop bleeding and/or cut tissue.

A laser with a wavelength of 2.013 µm that uses water as its primary target, offering potential as an alternative to CO2 lasers for endoscopic procedures.

A technique for generating short laser pulses by trapping light energy within a resonant cavity and releasing it quickly.

The pattern of light emission from a laser, characterized by factors like intensity, exposure time, and pulse duration.

The total amount of light energy incident on tissue, determined by the laser power and exposure time.

The length of time a laser pulse lasts, measured in seconds or nanoseconds.

The physical distance between the mirrors in a laser cavity, influencing the duration of laser pulses.

A type of laser used in aesthetic surgery, where its properties like cavity dumping allow precise manipulation of tissues.

The ruby laser's output is not a steady beam but a series of short, irregular bursts known as spikes. Each spike lasts a few microseconds with several microseconds between them.

Many long-pulsed lasers operate in a spiking mode, where the laser output is a series of short pulses due to the depletion and replenishment of the population inversion.

Longer wavelengths, like those of Er:YAG lasers, are absorbed by water and result in minimal thermal spread, causing precise incisions. Shorter wavelengths penetrate deeper and cause more widespread heating.

Q-switched lasers control the spiking of the output to produce a single, very short pulse, much shorter than the flashlamp lifetime.

Laser operation relies on creating an imbalance in the energy states of atoms, with a higher population in energized states, known as 'population inversion'.

The extinction length in water is the distance over which the laser beam's intensity drops to 1/e (about 37%) of its initial value. It's a measure of how far the laser beam travels before being completely absorbed.