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Tips and Information on Endometriosis: A Monthly Feature

Understanding Surgical Techniques in the Treatment of Endometriosis

By Andrew S. Cook, M.D.
OBGYN.net Editorial Advisor
Endometriosis Zone
Laparoscopy & Hysteroscopy
Hysterectomy and Alternatives
Chronic Pelvic Pain

Complete removal of endometriosis is dependent, to a large extent, upon the skill of the surgeon, and this is true no matter which surgical approaches or instruments are used.  The goal with surgery is to completely remove the endometrial implants while maintaining as much normal tissue as possible.

The current surgical tools available to remove endometriosis include: scissors; electrosurgery; harmonic scalpel; laser; or the endocoagulator. These tools can be used to excise, coagulate or ablative vaporize (Carbon 13 CO₂ laser and high pure-cut electrosurgery).

All surgical techniques used for removing endometriosis use either mechanical energy (e.g., mechanical scissors) or thermal energy (heat). Depending on how intense and how high the heat, one of two effects can occur to the tissue: coagulation or vaporization. Low-intensity heat results in coagulation, and high-intensity heat results in vaporization.

Each of the various surgical techniques available for the removal of endometriosis has certain advantages and disadvantages. Let's examine each of these:

Coagulation
In the past, coagulation has been one of the more common surgical techniques used to treat endometriosis. It is relatively quick, easy to use, and is available at most hospitals. Coagulation is a burning, or melting, of the tissue. Like any burn it is difficult to tell precisely how much tissue is destroyed. This is because the heat spreads slowly, and, just like a sunburn, the extent of the burn may not be apparent for hours or days. While this is a relatively simple technique to use, the fact that endometriosis often grows right on delicate organs such as the bowel, bladder, and the ureters (the tubes from the kidney to the bladder) means that it is virtually impossible to burn just the right amount of tissue to completely remove the endometriosis so that none is left behind, and at the same time avoid damaging normal vital organs. For these reasons, most nationally recognized surgeons who specialize in the treatment of endometriosis do not consider coagulation the preferred method for the surgical treatment of endometriosis (source:  38^th AAGL Global Conference on Minimally Invasive Gynecology)

Surgical instruments that can coagulate include monopolar electrosurgery, bipolar electrosurgery, some types of lasers, the harmonic scalpel, and the endocoaguator.

Preferred Techniques
While it is important to emphasize that none of the surgical techniques listed above has been shown in the scientific literature to provide results superior to the others, there does seem to be a general consensus among nationally recognized endometriosis surgeons that excision is preferred over coagulation for the treatment of endometriosis (source:  38^th AAGL Global Conference on Minimally Invasive Gynecology). Remember that complete removal or destruction of the endometrial implants is the goal of the surgical treatment of endometriosis.

There are two basic techniques in which a surgeon can remove or destroy the endometriosis: excision and vaporization. Excision means that the surgeon cuts around and removes the tissue. Vaporization eliminates the cells of the endometrial implants by turning the solids and liquids of the cell into vapor. Some types of surgical lasers, high current electrosurgery, and high intensity ultrasound devices can deliver very intense energy/heat that instantly boils the water in the cell (remember, cells are mostly water, with some proteins and other components). The water turns into steam, vaporizing and thus eliminating the unhealthy tissue.

Excision
Excision can be performed surgically in one of two ways:

1. By Mechanical Excision (ME), or
2. By Thermal Excision by Linear Vaporization (TEL-V).

Mechanical Excision (ME) uses only the mechanical shearing force of scissors, without the aid of electrosurgery. Thermal Excision by Linear Vaporization (TEL-V) uses electrosurgery, laser, or the harmonic scalpel to create the intense heat that results in vaporization. As stated in the American Association of Gynecologic Laparoscopists (AAGL) publication, even the most die-hard, "excise only" surgeons who use electrosurgery via scissors are, in fact, linear vaporizers¹.

Both Mechanical Excision (ME) and Thermal Excision by Linear Vaporization (TEL-V) offer several advantages, and are the mainstay of the successful surgical treatment of endometriosis. These methods of excision can quickly remove large amounts of tissue, and provide tissue for the pathologist to check under the microscope. Neither method damages or alters the appearance of the underlying tissue.

This is an important point. Whenever tissue is removed, the remaining underlying tissue must be assessed to determine whether all of the endometriosis was removed or whether deeper disease is still present. Sounds pretty good so far, but what is the disadvantage of excision? The primary disadvantage of excision is that it is fairly non-selective. Endometriosis not only grows on the surface of the peritoneum (the inside lining of the body), where it can be easily plucked off; it can also invade the underlying tissue. This invasive endometriosis can send out "fingers" of endometriosis, growing on and around vital organs (e.g., the bowel, blood vessels, ureter, bladder, etc.).

If the endometriosis being removed is separate from vital structures, then excision is a good approach. But if the endometriosis is growing on vital structures excision is not always the best choice, as it may require the removal of healthy tissue. In my opinion, if endometriosis is aggressively removed using only excision, there will be a higher incidence of bowel resection, ureteral resection, etc., because "the endometriosis was so advanced." But in reality, appropriate use of selective ablative vaporization would have removed the endometriosis without having to resort to removing normal tissue.

Vaporization
There are two basic types of vaporization: Linear Vaporization and Ablative Vaporization.

Figure 1 – Basic Types of Vaporization

As mentioned above, virtually all physicians who excise endometriosis are linear vaporizers using the technique Thermal Excision by Linear Vaporization (TEL-V). Because vaporization does not conduct heat, it does not distort the appearance of the cells next to or underneath the cells that are vaporized. The vaporization is performed in a line, resulting in a cutting of the tissue. This is the preferred method of most advanced endometriosis specialists (Source: 38^th AAGL Global Conference on Minimally Invasive Gynecology).

The second type of vaporization is Ablative Vaporization. For the same reasons that Excision by Linear Vaporization (TEL-V) is the preferred surgical technique, Ablative Vaporization is acceptable in limited situations as a touch-up tool after a preliminary process of excision, with the qualification that it is performed by surgeons who have the necessary surgical skills to recognize and remove endometriosis. The main drawbacks to Ablative Vaporization are:

1. The surgeon must be very thorough in ablating all of the tissue and not leaving any islands of endometrial tissue; and
2. The tissue undergoing Ablative Vaporization is destroyed and cannot be sent to the pathologist for evaluation.

For these reasons, Ablative Vaporization should only be used in select cases as an appropriate secondary tool in select areas, and not as the primary or sole method of removing endometriosis.

Ablative Vaporization can be performed with electrosurgery or with a Carbon 13 CO₂ laser. This technique offers several advantages. It is the most precise surgical tool available for the removal of endometriosis, because the packet of light energy is so intense and focused that there is no conduction of heat and no coagulation. Hence there is virtually no thermal (heat) damage to the tissue that is left behind.  It’s important to note that vaporization turns liquid water into steam, it does not burn tissue. This technique enables the surgeon to remove the endometriosis layer by layer. Another advantage of Ablative Vaporization is that the surgeon can examine the appearance of the remaining tissue, permitting an accurate assessment of whether endometriosis is still remaining or if normal tissue has been reached. This is especially useful when working on vital structures such as the bowel, ureters, blood vessels, etc.

Summary
While endometriosis is considered a benign tumor or at most a tumor of very low malignant potential, the removal of the scattered endometrial implants with wide excision and clear margins nevertheless provides the greatest chance of complete elimination of the disease. Debulking or only partial removal of the endometriosis will result in the persistence of disease, continued growth of the endometrial lesions, and most likely relatively rapid recurrence of symptoms². For these reasons many endometriosis surgeons feel that excision (with or without the aid of ablative vaporization) is the preferred surgical technique for the removal and treatment of endometriosis.

The very nature of heat delivery with coagulation is imprecise, resulting in a higher chance of both incomplete removal of the endometriosis and more extensive damage of normal tissue.  These significant drawbacks lead one to consider if the technique of coagulation for the treatment of endometriosis should be relegated to the past.

Finally, while it is important to understand the various surgical techniques, the real issue is the surgeon's skill in identifying and removing endometriosis. Good surgeons may use variations of the excision and vaporization surgical techniques described above based on personal preference, with equally good results. 

References

1.  Munro MG, Electrosurgery Basics. AAGL NewsScope. 2006, July-Sept: 4-5

2.  Taylor E and Williams C. Surgical treatment of endometriosis: location and patterns of disease at reoperation. Fertil Steril. 2010 Jan;93(1):57-61.