Some types of electrical energy are very useful for laparoscopy and thoracoscopy. Many grasping and dissecting forceps, as well as scissors and biopsy forceps have connections for monopolar cautery.
For endoscopy, the bipolar mode is used for ovariohysterectomies, ovariectomies, cholecystectomies, and dissections such as obtaining lymph node biopsies, lobectomies, tumor resections, adrenalectomies, etc.
The primary procedure is to coagulate prior to cutting, thus reducing blood and visibility loss. If hemorrhage develops during dissection and is modest, hemostasis can frequently be obtained by pinpoint monopolar cautery, bipolar cautery, or with hemostatic clips. Excessive hemorrhage requires the use of a suction/irrigation device and perhaps cleaning of end of the laparoscope. Uncontrolled hemorrhage can require conversion to an open surgery. Requirement to convert due to bleeding is rare for the experienced endoscopic surgeon.
Ligasure and Force Triad
Covidien provides energy equipment (LigaSure and Force Triad) that combine an electrical energy designed to produce minimal collateral injury with the ability to adjust current during sealing base on tissue impedance to current flow.
The current is a high flow with low voltage. For the LigaSure, feedback is performed by its internal computer at 200 times per second, and for the Force Triad at 3,333 times per second. Both devices are approved by the FDA to seal a 7mm vessel.
Although radiofrequency and electrocautery generators can provide sufficient energy for laparoscopic ovariohysterectomy and ovarioectomy in many dogs, LigaSure’s ability to manage larger patients is very useful and quicker. The LigaSure and Force Triad is also used for general surgery, such as tumor resections, soft palate amputations, limb amputations, prostatic surgery, liver lobectomies, and splenectomies, etc. In addition the Force Triad also provides modules for monopolar and for bipolar electrical energy. Thus, a surgeon can use two or three energy formats alternately during general surgery.
Below: The ForceTriad generator is approved to seal and divide vessels that are 7mm in diameter. Few vessels other than the aorta and vena cava exceed this diameter in the dog. A wide variety of endoscopic and non-endoscopic instruments are available to deliver this energy.
Above, left and right: The Force Triad is the next generation of the LigaSure. The one-third that is the LigaSure is improved over the original by more frequent decisions of adjusting current according to impedance (3,333 per second versus 200 per second); continuous energy versus pulsed energy; and real-time measure of impedance versus the initial impedance measurement. As a result, sealing is quicker with the Force Triad than the LigaSure, which remains much quicker than the traditional means of hemorrhage control and division of tissue. In addition, the other two power units of the Triad - monopolar and bipolar electrocautery - are also improved.
Above: The 5mm sealer-divider endoscopic forceps is excellent for endoscopic procedures such as ovarioectomy, ovariohysterectomy, cholecystectomy, adrenalectomy, partial pericardial resections, lymph node dissections, and other vascular dissections. Excellent compression of the tips is obtained by squeezing and locking the finger trigger. As with the HotBlade, the handle should be positioned in a comfortable hand position and the shaft with blades rotated using the rotating wheel within the handle to properly position the tips on either side of the tissue to be sealed and divided.
Above: Once the tips are compressed, the LigaSure is initiated by pushing continually on the thumb trigger. The LigaSure will emit a sound indicating that there is either good or poor tissue contact based on impedance measurements. If the contact is good, the unit will seal tissue until a change in the sound tone indicates vessel sealing.
Above: Once the tissue is sealed, the finger trigger is squeezed and a cutting blade is propelled within the tips to divide the sealed tissue. The tips are constructed such that some tissue is sealed beyond the point of division.
Above: Another Force Triad instrument is the Impact forceps that is used for traditional surgery. It seals and divides. The LigaSure current can be initiated to seal and the blade advanced to cut using controls within the handpiece.
Above: Application of a Impact for an emergency splenectomy. Some surgeons will ligate the main splenic artery and others prefer to only use the LigaSure sealing device. Regardless, the total laparotomy time can be less 30 minutes.