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'The vessel sealing system is very safe, fast and effective in controlling hamoorrhage'

One of the problems in surgery is bleeding. Whenever a surgery is performed a surgeon has to attempt total haemostais or complete stoppage of haemorhage. Let us assume that a small vessel of 4 mm like one supplying the gall bladder, if left unattended, then a patient can be killed in less than an hour. Therefore, from the days of evolution of surgery different methods of stopping bleeding from vessels have been explored.

Dr Sumit Chaudhuri

Diathermy

Diathermy is the use of high frequency electric current to produce heat used to either cut or destroy tissue or to produce coagulation.

• Mains electricity is 50 Hz and produces intense muscle and nerve activation.
• Electrical frequency used by diathermy is in the range of 300 kHz to 3 MHz.
• Patients body forms part of the electrical circuit.

Effects of diathermy:

• The effects of diathermy depends on the current intensity and wave-form used.
• Coagulation.
• Produced by interrupted pulses of current (50-100 per second).
• Square wave-form.
• Cutting.
• Produced by continuous current.
• Sinus wave-form.

Risk and complications:

• Can interfere with pacemaker function.
• Arcing can occur with metal instruments and implants.
• Superficial burns if use spirit based skin preparation.
• Diathermy burns under indifferent electrode if plate improperly applied.
• Channeling effects if used on viscus with narrow pedicle (e.g. penis or testis).

The Science of Vessel Sealing Technology

This is a technology which is different from conventional diathermy and provides a unique combination of pressure and energy to create vessel fusion and permanently fuses vessels up to and including 7 mm in diameter and tissue bundles, without dissection or isolation.

An optimised combination of pressure and energy creates the seal by melting the collagen and elastin in the vessel walls and reforming it into a permanent, plastic-like seal and results in virtually no sticking or charring. It does not rely on a proximal thrombus.

Feedback-controlled response system automatically discontinues energy delivery when the seal cycle is complete, eliminating the guesswork.

When the instrument determines the seal is complete, a tone sounds and output to the handpiece is automatically discontinued.

• Reduces thermal spread.
• Minimizes thermal spread to approximately 2 mm for most LigaSure(tm) instruments; average thermal spread is less than 1 mm when using the LigaSure Precise(tm) instrument and approximately 1.5 mm when using the LigaSure(tm) V instrument.
• A clinical study demonstrated that seals withstand 3x normal systolic blood pressure.
• High-burst-strength, feedback-controlled bipolar vessel sealing.
• Common usage of the system.

Why is the vessel sealing technology preferred:

In Carolinas Medical Center, Charlotte, North Carolina, USA, Carbonel, Joels CS et al did a study on laparoscopic bipolar vessel sealing devices in the hemostasis of small, medium, and large-sized arteries.

They studied the strength of the vessels sealed or the extent of surrounding lateral thermal injury-two important factors in maintaining hemostasis while preventing injury to surrounding structures. This study compared the burst pressure and extent of thermal injury of vessels sealed with the 5-mm laparoscopic LigaSure trade mark sealing device (LS) (Valleylab, Boulder, Colorado). Arteries in three sizes (2-3 mm, 4-5 mm, and 6-7 mm) were harvested from domestic pigs.

Conclusion: The LS produces supraphysiologic seals with significantly higher bursting pressures in vessels ranging from 4 to 7 mm. The LS seals increase in strength as the vessel size increases.

Peterson SL et al did a comparison of healing process following ligation with sutures and bipolar vessel sealing.

The ability to seal large vessels quickly and effectively, combined with an associated decrease in needle passes on the operating field, suggest benefits directly associated with the use of the electrothermal vessel sealing system. Perhaps a more promising finding lies in the shorter duration associated with the inflammatory response. The potential for seals composed of the patient's native tissue to reduce the inflammatory response may translate to a decrease in post-surgical adhesions.

Clinical studies are currently in progress to quantify the relationship between seals made with the LigaSure(tm) vessel sealing system and the incidence of post-surgical adhesions.

Harold KL of Department of Surgery, Carolinas Medical Center, made a comparison of ultrasonic energy, bipolar thermal energy, and vascular clips for the hemostasis of small, medium and large-sized arteries.

Advanced laparoscopic procedures have necessitated the development of new technology for vascular control. Suture ligation can be time-consuming and cumbersome during laparoscopic dissection.

Titanium clips have been used for hemostasis, and recently plastic clips and energy sources such as ultrasonic coagulating shears and bipolar thermal energy devices have become popular.

The purpose of this study was to compare the bursting pressure of arteries sealed with ultrasonic coagulating shears (UCS), electrothermal bipolar vessel sealer (EBVS), titanium laparoscopic clips (LCs), and plastic laparoscopic clips (PCs). In addition, the spread of thermal injury from the UCS and the EBVS was compared.

Methods: Arteries in three size groups (2-3, 4-5 and 6-7 mm) were harvested from freshly euthanized pigs. Each of the four devices was used to seal 16 specimens from each size group for burst testing.

Conclusions: LC secured all vessel sizes to well above physiologic levels. The EBVS can be used confidently in vessels up to 7 mm. There is no difference in the thermal spread of the LigaSure vessel sealer and the UCS.

Cuschieri A et al studied How safe is high-power ultrasonic dissection at Department of Surgery and Molecular Oncology & Surgical Skills Unit, Ninewells Hospital & Medical School, University of Dundee, Dundee, Scotland.

Objective: To evaluate the safety of ultrasonic dissection. Summary Background Data: High-power ultrasonic dissection is in widespread use for both open and laparoscopic operations and is generally perceived to carry a low risk of collateral damage, but there is no published evidence for this.

Results: Extreme and equivalent temperature gradients were generated by ultrasonic dissection with both systems. Heat production was directly proportional to the power setting and the activation time. The core body temperature of the animals after completion of the laparoscopic dissections rose by an average of 2.3 degrees C. The zone around the jaws that exceeded 60 degrees C with continuous ultrasonic dissection for 10 to 15 seconds at level 5 measured 25.3 and 25.7 mm for Ultracision and Autosonix, respectively.

At this power setting and with an activation time of 15 seconds, the temperature 1.0 cm away from the tips of the instrument exceeded 140 degrees C. Although there was no discernible macroscopic damage, these thermal changes were accompanied by significant histologic injury that extended to the media of large vessels and caused partial-to-full-thickness mural damage of the cardia, ureter, and bile duct.

Conclusions: High-power ultrasonic dissections at level 5 and to a lesser extent level 4 result in considerable heat production that causes proximity collateral damage to adjacent tissues when thecontinuous activation time exceeds 10 seconds. Ultrasonic dissections near important structures should be conducted at level 3.

Considering all these factors the vessel sealing system is very safe as well as fast and effective in controlling hamoorrhage and for haemostasis.