Ultracision®: the harmonic scalpel and its possible uses in maxillofacial surgery

Ultracision®: the harmonic scalpel and its possible uses in maxillofacial surgery

British Journal of Oral and Maxillofacial Surgery (2000) 38, 530–532 © 2000 The British Association of Oral and Maxillofacial Surgeons doi: 10.1054/bj...

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British Journal of Oral and Maxillofacial Surgery (2000) 38, 530–532 © 2000 The British Association of Oral and Maxillofacial Surgeons doi: 10.1054/bjom.2000.0502

BRITISH JOURNAL OF ORAL

& M A X I L L O FA C I A L S U R G E RY

TECHNICAL NOTE Ultracision®: the harmonic scalpel and its possible uses in maxillofacial surgery J. A. Sherman,* H. T. Davies† *Senior Registrar; †Consultant, Department of Oral and Maxillofacial Surgery, The Ipswich Hospital NHS Trust, Suffolk, UK SUMMARY. We report on the potential uses and benefits of a new development in incisive technology. The harmonic scalpel uses high-frequency mechanical energy to offer the surgeon controlled and precise incision and haemostasis. Vessels up to 2 mm in diameter may be sealed by coaptation with the blade before division. No special training or precautions are required before using this self-cleaning device. It produces considerably less smoke or smell than either diathermy or laser, which reduces the need for instrument exchanges and smoke evacuation. We think that it will be useful for tongue resections and possibly for neck dissections. © 2000 The British Association of Oral and Maxillofacial Surgeons

that allow cutting, coagulation, and dissection of tissue. The dissecting hook uses the inside curve of the blade to cut and dissect, and the outer blunt edge or flat side to coagulate (Fig. 2). The sharp hook permits simultaneous fast-cutting and dissection with the inner sharp curve of the blade, and coagulation in a similar manner as before (Fig. 3). Both blades are connected to rods, which are 32 cm long. Selection of blade is in accordance with the surgeon’s preference for the procedure being done.

INTRODUCTION The concept of ‘ultracision’ involves the application of an electrical current across a series of coupled pairs of negatively charged, ferroelectric, ceramic, disc-shaped crystals in a transducer to produce a balanced sinusoidal (or harmonic) ultrasonic wave form of high electroacoustic efficiency. By coupling a metallic rod to this device, the wave motion is converted into high-frequency mechanical motion at the tip of a blade located at the end of the rod. The blade is then able to cut and coagulate tissue simultaneously in a precise and controlled manner.1 This offers the surgeon many potential benefits. At the instrument–tissue interface, the vibrations cause hydrogen bonds to break, proteins to denature, and the formation of a sticky coagulum. Blood vessels are selectively spared from being divided. Coagulation is achieved with minimal thermal damage between 80 and 100°C, without the need for an electric current.2 Current machines operate at 55 500 Hz and require less energy than either cutting diathermy or laser.3 Five power levels are available. At level one, the instrument tip vibrates longitudinally with an amplitude of 50 µm, and is used to cut tissue slowly and coagulate collaterally. When the distance is increased to 100 µm (at level five) the effect is almost a pure cut with minimal coagulation.

ADVANTAGES The main benefits to the maxillofacial surgeon are effective haemostasis and less extensive tissue damage with better visibility than with diathermy or laser. Coagulation of blood vessels up to 2 mm in diameter is achieved by coaptation. Gentle pressure is applied with the flat surface of the blade at low power. It is suggested that this should be done over a wide area at two widely separated points before cutting in between. Larger vessels must be tied in the conventional manner. The reduction in operative bleeding should reduce the time spent achieving haemostasis with diathermy or ligatures. Unlike in electrosurgery, direct contact with tissue does not cause adhesion to the instrument, which reduces the amount of bleeding at the surgical site. The harmonic scalpel seals vessels mechanically as it incises without accumulating eschar on the blade or generating much smoke. This reduces the toxins and smoke-related smells associated with other forms of thermal surgery, and eliminates the need for smoke evacuation or diathermy to achieve haemostasis. In addition, the ultrasonic vibrations create a self-cleansing action. Instrument exchanges are reduced as there

EQUIPMENT The commercially available apparatus consists of a 220 volt ultracision generator and cart (Fig. 1), footswitch, a linking cable, and the handpiece which contains both the transducer and the harmonic scalpel blade. Two 5-mm hard sheath blades are available 530

Uses of the harmonic scalpel in maxillofacial surgery

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Fig. 1 – The Ethicon endosurgical ultracision generator (A) and handpiece (B).

Fig. 2 – The dissecting hook.

Fig. 3 – The sharp hook.

is less need to cleanse the blade and vessels may be coagulated with the side of the activated blade. There is some atomization of water molecules while the scalpel is being used, but the resultant mist dissipates rapidly. The thermal injury zone with the harmonic scalpel extends to a depth of 50–150 µm, which appreciably reduces mucosal damage and perforation of vessels. This minimal level of lateral thermal damage compares favourably with both laser and electrosurgery, the thermal effects of which can be measured in millimetres. Activation and pressure are required before cutting starts, which minimizes the risk of accidental incision within or outside the intended field. However, studies in pigs have shown that tissues that look normal may

be histologically dead. The lack of tissue discolouration from lower operating temperatures may therefore mislead the surgeon about the amount of damage to adjacent structures.4 The manufacturers (Ethicon Endo-Surgery, Livingston, West Lothian, UK) claim that the avoidance of tissue dessication and charring promotes rapid healing and more tensile strength than other thermal devices. Neither nerves nor muscles are stimulated during use, which should reduce postoperative discomfort. Some concern has been expressed that, because tissue is divided at a low temperature, viable cancer cells or HIV particles may be present in the generated mist. Smoke analysis after experimental dissection in a rat

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British Journal of Oral and Maxillofacial Surgery

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Fig. 4 – (A) Before resection of the tongue; (B) during operation (note the relatively bloodless field); (C) postoperative view.

CONCLUSIONS The harmonic scalpel has a potential role in head and neck tumour surgery. Both surgeon and patient should benefit from its advantages. Its broader applications have yet to be defined in other areas of our specialty. REFERENCES 1. 2.

tumour model failed to identify any viable cancer cells. However, eye protection is recommended as hepatitis may be transmitted during open surgery.5 No data are currently available regarding HIV transmission. Unlike laser, no special training or precautions are necessary. The electrical risks of diathermy are avoided. At the time of writing, the manufacturers recommend that the disposable blades should be used only once. Re-sterilization of the harmonic scalpel will allow it to be used on any number of patients and appreciably reduce the procedure-related expenses after the initial outlay. Even so, the initial outlay and running costs are much less than for a laser. The device has been successfully used in both open and laparoscopic general surgical and gynaecological procedures. We have used the harmonic scalpel set at power level three for resections of squamous cell carcinoma of the tongue. A clear, relatively bloodless field was obtained with good visibility (Fig. 4). One of the authors (H.T.D.), has used it to do a radical neck dissection on an anaesthetized pig.

3. 4. 5.

Ultracision product information. Livingston, West Lothian: Ethicon Endo-Surgery, 1999. Kimber C, Dunkley P, Cuschieri A. Essentials of ultrasonic dissection for surgeons. University of Dundee: Surgical Skills Unit, 1998. Muller W, Fritzch G. Mechanicotechnical basics of surgery using invasive ultrasound energy. Endosc Surg 1994; 2: 205–210. Kadesky KM, Schopf B, Magee JF, Blair GK. Proximity injury by the ultrasonically activayed scalpel during dissection. J Pediatr Surg 1997; 32: 878–879. Matsumata T, Kanematsu T, Okadome K, Sugimachi K. Possible transmission of serum hepatitis in liver surgery with the ultrasonic dissector. Surgery 1991; 109: 284–285.

The Authors Jeremy A. Sherman FDS, FRCS Ed (OMFS) Senior Registrar Huw T. Davies FDS, FRCS Consultant Department of Oral and Maxillofacial Surgery The Ipswich Hospital NHS Trust Suffolk UK Correspondence and requests for offprints to: Mr J. A. Sherman, 28 Albany Mews, Kingston-upon-Thames, Surrey, KT2 5SL, UK Paper received 12 July 1999 Accepted 20 March 2000