There are several surgical tools designed to remove (ablate) tissue
and control any bleeding that results. Each tool has its own set of
operating characteristics. The surgical tools that remove, destroy,
incise and coagulate tissue include
(1) scalpels and scissors,
- a variety of blade sizes and shapes as well as scissor sizes and
shapes are available.
- the knife is ideal for cutting the skin, with research documenting
greater tensile strength and faster healing in skin cut with a knife
as compared to the carbon dioxide laser, harmonic scalpel or electrosurgical
- scissors are ideal instruments for dissection of tissue and can
also be used effectively to cut tissues ranging from tough to filmy.
These instruments can be used to remove tissue on which endometriosis
has grown. Excised tissue will include some normal tissue and any
bleeding created needs to be controlled. This has limited the use
of these instruments in the routine treatment of endometriosis.
(2) electrosurgical devices,
- these can be adjusted to provide different amounts of power (20
to 80 watts is usually used) with different blends of cutting and
coagulation. The electrical generator has variable power (wattage)
settings. Pure cutting is a continuous delivery of undamped electrical
energy so that a relatively low voltage is required to achieve a particular
chosen power (wattage) usage. Pure coagulation is an interrupted or
damped delivery of electrical energy such that current is flowing
less than 10% of the time (it flows only 6% of the time) so that a
much greater peak voltage is required to achieve the same chosen power
(wattage) use (compared to cutting). Blends of cutting and coagulation
allow the surgeon to select the relative degree of damping used. In
the rare situations in which I use cautery to cut (such as during
hysteroscopic surgery) I typically use blend 1 which applies current
80% of the time and gives just a little coagulation as compared to
- a wide range of effects is possible. Pure cutting current has little
char (which acts to coagulate). At the other end of the spectrum,
fulgaration produces a superficial layer of char by holding the electrode
a small distance from the tissue and allowing the current to spark.
Lateral thermal damage with these instruments due to heating of surrounding
tissue limits their use in the ablation of endometriosis, especially
when close to other vital structures.
(3) thermocoagulation devices,
- these differ from electrocoagulation devices in that they do not
deliver high frequency electrical current to generate heat in the
- these devices deliver heat directly via a hot metal tip that is
applied to tissue.
- these devices are adjusted to deliver heat at up to 160 degrees
centigrade, and tissue generally turns white when desiccation causes
- of course it is necessary to avoid inadvertently touching tissues
other than those desired while using this tool and during its cool
- this is an ideal coagulating device but extensive lateral thermal
damage has limited its use in the treatment of endometriotic lesions
that are close to other vital structures.
- these devices can deliver fine beams of intense energy to tissue
with the power density (watts per square centimeter) at the tissue
site determining the effect (vaporization, excision, coagulation).
- there are different laser systems. These include fiber delivery
via KTP-532 or Nd:YAG lasers where the energy released from the tip
of the fiber diverges to dissipate the energy (highest power density
is closest to the tip of the laser fiber). The carbon dioxide (CO2)
laser focuses the laser energy with a series of mirrors into differing
size spots that help to determine the power density at the tissue.
- the CO2 lasers can deliver power in different wave forms that determine
the power density achieved and amount of lateral thermal damage. The
most common laser in use for most fertility work during laparoscopy
is the CO2 laser and the optimal wave form for fertility work is the
ultrapulse wave. There are noticeable differences in the effects produced
by the lasers that are currently available.
- Laser is a precise and efficient method of destroying tissue. Laser
light can be focused into a very narrow beam of photons since the
waves of light that are produced are coherent (each wave is "in
phase" as it travels through time and space), monochromatic (each
wave has an identical wavelength), and collimated (the waves are parallel
to one another). When the laser light is absorbed into tissue, the
tissue heats up and may be damaged.
- When tissue is heated to greater than 100 degrees centigrade (C)
the water within the cells vaporizes and the cells burst (the conversion
of liquid water to steam results in a 1000 fold increase in volume)
to result in tissue separation. If the tissue is heated to greater
than 57 C the proteins within the cells that are necessary for cellular
function are irreversibly denatured and these proteins no longer function
(the cell dies). If the tissue is heated to greater than 45 C there
is swelling (edema) and frequently eventual cell death.
- The goal of laser laparoscopy for fertility work is to remove or
vaporize abnormal tissue while leaving as much of the adjacent normal
tissue intact. To accomplish this goal, the duration of the transmitted
laser energy can be manipulated. Continuous laser energy may be applied
to tissue but this results in considerable thermal heating and damage
to surrounding tissue (similar to cautery). Superpulse and ultrapulse
laser settings transmit short pulses of laser energy with long interpulse
intervals to limit the spread of thermal damage to surrounding normal
tissue (by enhancing interpulse tissue cooling) and produce highly
precise areas of tissue vaporization. This allows the surgeon to destroy
the abnormal tissue while minimizing thermal damage to the surrounding
(5) the harmonic scalpel, and
- this is a device that incorporates a tip that vibrates at an ultrasonic
frequency to rapidly denature proteins and separate tissue with little
- conceptually, this is a great tool for ablation of endometriosis
and lysis of adhesions.
- experience with the harmonic scalpel has not yet led to widespread
acceptance of this tool. Additionally, the results seen on second
look laparoscopy several weeks following its use have had mixed findings.
(6) the cavitron ultrasonic surgical aspirator (CUSA),
- this is widely used for tumor debulking by gynecologic oncologists.
It has a vibrating tip that reacts to an alternating electromagnetic
field (alternates 23,000 times per second) and produces significant
heat such that cooling is provided by saline liquid solution sprayed
over the tip at a rate of 3-10 ml per minute. This is not commonly
used for treatment of endometriosis.