激光在腹腔镜手术

LASER IN LAPAROSCOPIC SURGERY

                               
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Recently laser technology has gained wide-spread use within almost all fields, including laparoscopic surgery. A laser is a device that emits light (electromagnetic radiation) via a procedure for optical amplification based on the stimulated emission of photons. The term "laser" was initially an acronym for Light Amplification by Stimulated Emission of Radiation. The emitted laser light is notable for its high degree of spatial and temporal coherence, unattainable using other technologies. Both laser and electrosurgery work on an identical biological principle by intracellular fluid is intensively heated causing the cell membrane to explode as in cutting, or to slowly dehydrate the process of coagulation during minimal access surgery.

Laser surgery was introduced in the early 1950s, however it didn't gain popularity before last ten years. Electrosurgery, in use since the turn of this century, uses high frequency (radio-frequency) energy for cutting as well as other forms of coagulation. There are various types of lasers. In this review we refer to the CO2 laser, not another modalities such as YAG, etc.

BIOLOGICAL ACTIONS OF LASER AND ELECTROSURGERY

In electrosurgery, the high density of the RF current applied through the active electrosurgical electrode leads to a cutting action, provided the electrode includes a small surface which can be use with versatile laparoscopic instruments like Hook, Aspiration Needle, Maryland, Tritom, Spatula and even with Scissors..

The efficiency of electrosurgery is depending on

• The shape from the electrode
• The frequency and wave modulation
• Peak-to-peak voltage
• Current and output impedance from the generator
  

The cut can be smooth, with absolutely no arcing, or it may be charring and burn the tissue. This great variation of tissue effects is generally ignored or misunderstood, and that's why some surgeons claim that the cut by having an electrosurgical scalpel provides better wound healing than the usual laser, while some claim the reverse. Electrosurgical coagulation may be carried out in many different forms slow, delicate contact coagulation with bipolar forceps, to light charring and burning within the spray coagulation mode. The biological effect, accordingly, significantly is different from gentle tissue dehydration to burning, charring and even carbonization. The temperature differences during. the different coagulation processes may vary between 100 degrees Celsius to more than 500 degrees Celsius.

Reviewing these many variables, it's possible to understand why claims are being produced in favor of laser surgery. The laser beam includes a cutting effect similar to electrosurgery, without tissue contact but, since there are fewer variables using the laser, the cut is more uniform. This may be a benefit for many surgeons, but a disadvantage for other surgeons especialy in laparoscopic surgery because of loss of depth perception, depending on many factors. Coagulation with the laser is comparable to spray coagulation mode of electrosurgery, Spray of electrosurgery is coagulation current from distance but perhaps more controllable and predictable. Again, this depends on the instrumentation and experience of the surgeon with the different modalities.

CUTTING WITH LASER AND ELECTROSURGERY

The electrosurgical cutting electrode can be a fine micro-needle, a lancet, a knife, a wire or band loop, a snare, or even an energized scalpel or scissors. This suggests the enormous variations, and also the requirement to choose the proper device, because the electrode also determines the cutting performance. Additionally. the present waveform is really a significant factor in the cutting performance. An even, non-modulated current is much more ideal for scalpel-like cutting, whereas the modulated current gives cuts with predetermined coagulation. The output high intensity selected, as well as the output impedance from the generator, are also important regarding cutting performance. Having so many parameters and choices, there is no wonder that some surgeons are unhappy with the cutting performance of the electrosurgical system; some believe that choosing the proper electrode alone guarantees the required results. If all the parameters mentioned are taken into consideration, with understanding, the electrosurgical cut is going to be precisely the way the most discriminating surgeon desires.

Cutting using the laser looks to become simpler with regards to the number of parameters to be considered; the surgeon needs only to concentrate on the beam, have it in focus, and select the correct intensity. However, tissue excavation or snaring is merely difficult with the laser.

TARGETING THE SURGICAL AREA

The targeting of the surgical area is obviously more standard with the electrosurgical method because, even under the microscope, the active electrode is first aligned to the intended approach, after which the generator is activated. With forceps coagulation, unipolar or bipolar, the targeting isn't just more standard, however the forceps are also used to mechanically close the vessel. This really is something the laser cannot do. The targeting from the laser beam is a lot more critical, and usually requires a costly optical system. When the laser is activated, the beam better be on target; no mechanical tissue manipulation with the active electrode is possible.

LASER IN TRANSURETHRAL RESECTION OF PROSTATE (TURP)

Endoscopic surgery for prostate inside the urinary bladder became possible after the electrosurgical modality was introduced. While cryo has also been used in this discipline, it has not established itself as a practical method. The YAG laser is now being introduced for certain coagulating processes in the bladder, with promising results. However, TURP remains an electrosurgical operation.

EXCAVATION OF TISSUE

The active electrosurgical electrode could be shaped into any form suiting the anatomical requirements. The tissue removal, specifically in tumor surgery with wire and band loop electrodes, is a practical and preventative method over tissue removal using the cold steel.
The laserlight isn't suitable for tissue excavation.

OPEN-AIR COAGULATION WITH LASER AND ELECTROSURGERY

For this surgical treatment, both modalities are perhaps equally suitable, plus some favor the laser as a more predictable modality. However if the surgeon chooses the proper waveform, intensity, and electrode, he can produce predictable and delicate results. Dermatologists and gynecologists have demonstrated electrosurgery to be free of complications. If important parameters aren't carefully followed, neither electrosurgery nor laser modality is going to be free from difficulties. It is generally claimed how the laser beam is superior in pinpoint coagulations. Under the microscope, however, one can demonstrate that the micro-electrosurgical process may be equal and maybe simpler to apply if your microsurgical unit and electrodes are used.

COAGULATING WITH UNIPOLAR AND BIPOLAR FORCEPS

With proper use, electrosurgery procedures have become simpler, reducing operating time and loss of blood, especially when the electro-hemostat or forceps are used. With bipolar forceps and also the appropriate generator, the descriminating, delicate microsurgical procedures can be carried out.

LASER IN ENDOMETRIOSIS

Since endometrial tissue could be manipulated during laparoscopy, major surgery could be avoided. One method of tissue manipulation involves utilizing a carbon dioxide laser system. The benefit of this type of laser is the fact that there is minimal formation of scarring or tissue shrinking. The process is well-tolerated and required a brief hospital stay. Laser manipulation of endometrial tissue can be performed during the time of the initial laparoscopy, allowing patients to try conception sooner. No injuries or complications is brought on by the laser light treatments in Endometriosis in experienced hand.

SAFETY FOR PATIENT AND SURGEON

Each electrosurgical and laser modalities are secure in laparoscopic surgery when the devices are saved in perfect working condition and all sorts of technical requirements are fulfilled. Surgical accidents with both electrosurgery and laser have been reported. Most were brought on by insufficient attention and respect for proper requirements and treatments.

THE SMOKE PROBLEM

The two electrosurgery and laser surgery are recognized to produce undesirable smoke, compared with cold steel surgery. The smoke derives from the burning from the tissue, being a significant problem in endoscopic surgery. With electrosurgery, the amount of smoke produced might be significant or insignificant; in bipolar applications or cutting with non-modulated current, there is little smoke, if any.

With laser surgery, there's always a great amount of smoke due to the extremely high temperatures which make the cell to lose up. In electrosurgery, exactly the same way be true when spray coagulation, or heavy blending cutting, is performed. However, in delicate procedures, for example microsurgical cutting and bipolar coagulation, the surgical process is conducted at low temperatures and, thus, tissue dehydration instead of tissue burning occurs.

Specifically in laparoscopic interventions, insufflators with an increased flow rate and smoke exhaustion are essential when laser applications are carried out. These are not necessary during electrosurgical procedures.

COST EFFECTIVENESS

A rule of thumb states that each output watt from the laser costs about $1,000, compared with $10 for electrosurgical equipment. This means that a typical laser costs between $20,000 to $50,000 in contrast to an electrosurgical unit price of between $1,000 and $5,000. Operating expenditures maintenance and repair costs are much more in laser compare to electrosurgery. Electrosurgical units are relatively reliable and, in event of a breakdown, the repair rarely exceeds 20% from the purchase price.

CONCLUSION

"The laser: is still not method of alternative in laparoscopic surgery except a few of the disease like endometriosis. The laser receives a massive publicity like a "Star Wars" technology. The laser will need to show more features, applications and reliability before it will succeed in the armamentarium of surgical technology and types of procedures. The laser will discover its place but, at this time, there's excessive enthusiasm and nonobjectivity displayed by many laser marketers.