Page 28 - Aspire April -2023 Vol 8 / Issue 2

REPRODUCTIVE SURGERY SIG (includes Minimal Invasive Surgery)
Will laser energy in gynaecological surgery replace conventional electrosurgery?
By Professors Maria Antonia Habana and Huang Xiao-Wu and Associate Professor Herbert Situmorang
The employment of laser energy in gynaecological surgery has encountered both popularity and predicament.
The initial use of laser energy was aimed to overcome electrosurgery adverse events such as insulation failure, direct coupling and lateral damage.
It started in 1961 with the application of the CO2 laser in surgery right after laser discovery by Theodore Maiman the previous year. The CO2 laser then became well known for its cutting precision and minimal damage to collateral tissues, as it was well absorbed in water.
In gynaecology, the CO2 laser initially was used by Kaplan and colleagues in 1973 for treatment of cervical erosion. The fast adoption and progress of laparoscopic surgery during that period had shaped many trends in gynaecological surgery, including the use of lasers.
Many other laser types were invented including KTP, Argon, Er-YAG, Nd-YAG and diodes.
After gaining peak popularity in the 1980s, electrosurgery has shed the notoriety of the CO2 laser for two main reasons. It is more compatible with the laparoscopy device and cost effective.
Although the later generation of the CO2 laser was flexible, its use has been confined mainly to robotic laparoscopic surgery.
The KTP and argon laser, with similar wavelength – 514 and 533 nm – has several advantages compared to the CO2 laser, namely selectively absorbed by haemoglobin, less plume production, and an easy delivery system that uses lower power settings in the range of 5–10 W.
The main disadvantage is the need to wear special glasses that distort the view of the pelvis and make it difficult to visualise small implants of endometriosis. 1
Nd YAG lasers can produce different wavelengths, but the most common emission wavelength is 1064 nm.
This laser energy is poorly absorbed by water, giving an average depth of penetration of 3-4 mm.
It can operate in continuous or pulsed modes and it can be transmitted through quartz fibres (the bare quartz fibre and the quartz fibre with a sapphire contact tip).
This property of being poorly absorbed by water makes the Nd YAG laser an excellent tool for hysteroscopic surgery. In addition, the wave can be transmitted through an operating hysteroscope.
The bare fibre on contact with tissue creates an area of coagulation that can extend 3-5 mm into the tissue, while by using a sapphire tip at the end of the fibre the laser energy can be focused and converted into heat. This results in the ability to vaporise without the extensive tissue coagulation caused by the bare fibre.
Unfortunately, the sapphire tips need to be cooled with a coaxial flow of gas or liquid through the fibre making it contraindicated for hysteroscopic surgery. But they can be safely used for abdominal surgery.
Recently, it has been become possible to modify bare fibres for use in a contact mode by moulding the tip and creating sculptured tips of various types such as scalpel tips and balls. Until recently, this made the Nd YAG laser remain as the preferred laser in the hysteroscopy field.
The diode laser is the newest type of laser and recently has had a great development for a variety of medical applications, especially surgery due to its miniature size, cost effectiveness, relative simplicity of use and the range of available wavelengths.
They produce wavelengths from 980 to 1470 nm that simultaneously confer a contemporary absorption in haemoglobin and H2O, and therefore excellent ability of haemostasis, cutting and vaporization.
Compared to the CO2 laser, the diode laser creates a significantly higher haemostasis.
The diode laser has now been widely used in many gynaecologic laparoscopy surgeries, one of which is in treating the endometrioma and deep endometriosis. A study has shown that the diode laser could preserve ovarian function as it only penetrates 0.3-0.6 mm depths of the tissue. 2
Munros and colleagues (2019) confirmed the superiority of CO2 laser vaporisation in preserving ovarian reserve compared to laparoscopic stripping. It does so by reducing the accidental removal of healthy tissue with minimal inflammatory response that does not negatively affect the ovarian reserve in terms of AMH and AFC at six months after surgery.
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