Treatment

DESCRIPTION OF CONDITION:

General surgery includes the surgical treatment of abdominal organs including intestines, esophagus, stomach, colon, liver, and bile ducts. Many of these organs can be treated using a laser due to its versatility.  For example, the laser is used for laser induced thermo therapy (LITT) of liver tumors, esophago-tracheal fistulae, colorectal carcinomas, angiodysplasia, erosion of the gastric membrane, colonic polyps, esophagal stenoses, or hemorrhoids. There are three methods for treating tissue in general surgery with laser:

• Coagulation
• Vaporization
• Cutting

PROCEDURE:

Coagulation:

Coagulation is irreversibly denaturizing proteins, both functional and structural.

Superficial coagulation can be obtained by using high laser power density, short irradiation time and no overlapping of irradiated areas.

Deep coagulation is generated by heat diffusion to deeper tissue layers, however the absorption of the laser light only happens at the first few millimeters below the surface.

The coagulated volume is generated by a combination of medium laser power density, long irradiation time and cooling of the surface. Tissue shrinkage is achieved by dehydrating the tissue or the contraction of collagen fibers.

The Dornier Medilas fibertom 5100 (Nd:YAG laser) and the Dornier Medilas D fibertom (diode laser) are optimal for coagulating tissue.

Interstitial Laser Coagulation (ILC):

Extremely large coagulation volumes can be generated by interstitial laser coagulation. In this procedure, thin lightguides, with special cylindrical application tips that diffusely emit the laser light, are inserted into the tissue to be treated.  The tissue is then irradiated from inside.
Dornier MedTech supplies lightguides with different application tips and radiation geometry in order to achieve an optimum treatment result.

Special patented irradiation software make it possible to provide time-saving therapy.
The patented LPS mode provides protection from thermal damage to the applicator tips. If the tips become carbonized the laser radiation is immediately switched off preventing overheating.
Coagulation zones up to 4 cm in diameter can be generated using water-cooled application catheters and simultaneous irradiation with a variety of catheters.

Primary applications are laser induced thermo therapy (LITT) of liver tumors and ILC of benign prostatic hyperplasia (BPH). Damaged tissue is absorbed or transformed by the body.

If higher power densities or long radiation times are applied, laser radiation causes tissue vaporization. This vaporization directly follows carbonization of the tissue surface.

Once the surface is carbonized absorption increases, leading to immediate vaporization.

Thanks to the coagulation zone below the vaporized volume capillary vessels are occluded immediately. In case of stronger perfused tissue (e.g. tumors) or larger vessels hemostatses can be accomplished by pre-coagulation of the tissue to be vaporized.

Lightguides with bare fiber tips or with special application tips can be used to cut or vaporize tissue efficiently during contact. In this case, carbon deposits occur on laser energy contact and the tips become slightly blackened.
The tip heats up to several hundred degrees and carbonizes the tissue again on contact due to the radiation absorption caused by this procedure. In this way, the cutting radiation always meets carbonized tissue and causes vaporization immediately.
Contact cutting is possible both in air and in a liquid environment.
Since the radiation meets a carbonized, absorbing tissue surface, it cannot penetrate into the tissue.  Although the coagulation seam is extremely small and only caused by heat conduction, a seam of 0.3 - 0.5 mm gives sufficient haemostatic reliability.

Cutting in pulsed mode using short pulses reduces the thermal conduction effect and provides an even finer coagulation seam, making it possible to work on small, bony structures.

ALTERNATIVE TREATMENT OPTIONS:

Open surgery – The organs mentioned above can also be treated by open surgery, which is a more invasive treatment method. Side effects are usually higher and the healing time for the patient is longer than it is for laser treatments. Additionally there is less bleeding with the laser treatment.