HARMONIC SCALPEL

The Harmonic Scalpel uses ultrasonic technology, a unique energy form that allows both cutting and coagulation of hemorrhoidal tissue at the precise point of application, resulting in minimal lateral thermal tissue damage. Because the Harmonic Scalpel uses ultrasound, there is less smoke than is generated by both lasers and electrosurgical instruments. The Harmonic Scalpel cuts and coagulates by using lower temperatures than those used by electrosurgery or lasers. Harmonic Scalpel technology controls bleeding by coaptive coagulation at low temperatures ranging from 50ºC to 100ºC: vessels are coapted (tamponaded) and sealed by a protein coagulum. Coagulation occurs via protein denaturation when the blade, vibrating at 55,500 Hz, couples with the protein, denaturing it to form a coagulum that seals small coapted vessels. When the effect is prolonged, secondary heat is produced that seals larger vessels. Because ultrasound is the basis for Harmonic Scalpel technology, no electrical energy is conducted to the patient.

By contrast, electrosurgery coagulates by burning (obliterative coagulation) at temperatures higher than 150ºC. Blood and tissue are desiccated and oxidized (charred), forming an eschar that covers and seals the bleeding area. The reduced postoperative pain after Harmonic Scalpel hemorrhoidectomy compared with electrocautery controls likely results from the avoidance of lateral thermal injury.