Experience With Ultrasound Scissors and Blades (UltraCision) in Open and Laparoscopic Liver Resection

Abstract

Objective

The authors used new ultrasonically activated scissors and blades in open and laparoscopic liver resections to investigate their capabilities.

Summary Background Data

Despite standardized techniques for liver resection, the surgical death rate ranges from 4% to 20%. Dissection of liver parenchyma may cause considerable blood loss. Further complications include liver failure, hematoma, infections, and bile leakage. The surgical technique is an important factor in preventing intraoperative and postoperative complications. Various techniques have been developed for safe and careful dissection of the liver parenchyma. In addition to blunt dissection using the “finger fracture” technique, various ultrasonic dissectors, water jet dissectors, laser systems, and specially prepared suction devices have been used, but none of these techniques can achieve complete hemostasis during dissection.

Methods

The instrument was used in open and laparoscopic liver resections. It works by means of a longitudinally vibrating blade or scissors in tissue dissection, coagulation, and preparation. Denaturation of protein and coagulation of vessels up to 2 to 3 mm is possible as a result of the vibration. In this prospective study of a consecutively sampled case series of 41 patients, the author sought to gain experience in handling this instrument and in its capabilities, and they also measured the extent of intraoperative and postoperative blood loss.

Results

The UltraCision was used for 64 open liver resections in 39 patients and for 2 laparoscopic liver resections in 2 patients. Blood loss in laparoscopic resections was less than 50 mL; in open resections it averaged 820 mL. Eleven patients (28%) needed blood transfusions. There were no biliary leakages or abscesses. One patient died after postoperative bleeding leading to fatal liver failure after 4 weeks. Handling of the instrument and cutting and coagulation quality were satisfactory.

Conclusions

The advantages over other resection techniques are limited heat and smoke generation and the lack of current flow through the patient. The handling and coagulation and cutting quality of the UltraCision appeared satisfactory and safe. The new instrument can be recommended for laparoscopic and open resections of the liver.

Despite standardized techniques for liver resection, the surgical death rate ranges from 4% to 20%. ^1–4 Dissection of the parenchyma of the liver may cause considerable blood loss. Further complications include liver failure, hematoma, infections, and bile leakage as a result of inadequate closure of the resection area of the liver.

Surgical techniques are an important factor for preventing intraoperative and postoperative complications. ³ Various techniques have been developed for safe and careful dissection of the liver parenchyma. In addition to blunt dissection using the “finger fracture” technique, ¹ various ultrasonic dissectors, water jet dissectors, laser systems, and specially prepared suction devices have been used. ^2–8 None of these techniques can achieve complete hemostasis during dissection. Consequently, blood vessels and biliary tract branches need to be clipped or sutured.

In laparoscopic surgery dissection of parenchyma is performed using an electric hook or scissors to achieve a bloodless operating field. However, the use of electric coagulation may cause severe complications by damaging nearby organs (i.e., the common bile duct during cholecystectomy or the small bowel). ⁹

The UltraCision scissors discussed in this article were originally developed for laparoscopic surgery. They meet the requirement for a safe instrument for laparoscopic preparation. ^10–15 In this article we will present our experiences with the new technique of ultrasound dissection. In our clinic this cutting device is mainly used in laparoscopic surgery for dissection of tissue, but we consider it an appropriate instrument for liver dissection. Because of its simultaneous hemostatic and coagulating effect, it might theoretically offer a considerable advantage over the suction knife technique used in our clinic for liver resection.

The aim of our study was to prove the suitability of the ultrasound scissors (Harmonic Scalpel, UltraCision, Ethicon Endosurgery) for the dissection of liver parenchyma in laparoscopic and open surgery in routine clinical practice; in addition, we wanted to see whether there are advantages over other techniques.

METHODS

In this prospective study we gained experience with the new ultrasound dissector in a consecutively sampled case series of 41 patients from January 1998 to August 2000.

Ultrasound Dissector

The ultrasound scissors system includes an ultrasound generator with a foot switch, a reusable handle for the scalpel, and the cutting device with scissors. A round coagulator and laparoscopic coagulation hooks are also available. The round coagulator, the two blades for the scalpel, and the scissors can be used through 5-mm and 10-mm trocars. Shorter coagulation scissors and blades can be provided for open surgery. Both the scissors and all the 5-mm instruments are disposable. Prices range from $120 to $250. The 10-mm blades can be sterilized and can be used in at least 30 operations.

Function

The blade’s longitudinal vibration, with a frequency of 55,500 vibrations per second (55.5 kHz), can dissect parenchyma easily. The blade’s movement range is a distance of about 50 to 100 micrometers. An acoustic transformation system of piezoelectric elements in the knife’s handle transforms electrical energy into mechanical energy. The lateral spread of the energy is minimal (500 micrometers).

The coagulating effect by means of protein denaturation is caused by destroying the hydrogen bonds in proteins and by the generation of heat in vibrating tissue. The cutting derives from a saw mechanism in the direction of the vibrating high-frequency blade. The intracellular generation of vacuoles makes the correct dissection of different layers of tissue even easier.

Blood vessels up to 2 to 3 mm in diameter are coagulated on contact of the tissue with the vibrating metal. For coagulation of larger vessels, exertion of pressure with the side or curve of the blade for 3 to 5 seconds is required. ^10,16

The instrument is operated by a foot switch; the cutting speed can be varied in five steps. The hemostatic coagulating effect is better in a low-speed position. Installation of the system is relatively easy and can be performed in 5 to 10 minutes.

Surgical Technique

The new ultrasound scissors were used for laparoscopic and open liver resections from January 1998 to August 2000. Preoperative diagnostics and patient preparation were based on general guidelines as recommended by the German Surgical Society. A separate consent was not considered necessary because the UltraCision instrument is already being used in a wide spectrum of operations.

In laparoscopic procedures, pneumoperitoneum was introduced after the placement of an optical trocar through a small subumbilical incision. Two or three additional trocars were positioned, depending on the surgical requirements. After partial mobilization of the liver to achieve an optimal view, the sickle-shaped blade was used through a 5-mm trocar for the resection in both cases. For open surgery, after a right or bilateral horizontal incision in the upper abdomen (in some patients extended by an upper midline incision), the liver was mobilized according to the individual requirements of the resection.

To achieve a better and more effective coagulating effect, the portal structures are occluded by a tourniquet. Then the liver capsule is incised with electrocautery to outline the plane of incision. The underlying liver tissue can now easily be divided using the UltraCision instrument. Both the scissors and the hook can be used for dissection; however, we believe the scissors provide a better coagulation effect. Larger vessels and biliary ducts are either doubly clipped with titanium clips or divided with clamps and sutured with 4-0 polypropylene. Especially in the periphery, the UltraCision is an ideal dissection instrument: with the absence of large vessels and bile ducts, nearly all of the parenchyma can easily be divided without causing bleeding, bile leakage, or trauma.

After completion of the resection the tourniquet is opened and the remaining cut surface carefully inspected for residual bleeding or nonoccluded bile ducts. Again, the cut vessels or bile ducts are sutured with 4-0 polypropylene. We believe it is unnecessary to pass heavy mattress sutures completely through the substance of the liver. However, we frequently cover the raw liver surface with fibrin-collagen sponges. In seven instances, an omentoplasty to cover large defects was carried out in addition.

RESULTS

From January 1998 to August 2000, 66 liver resections in 41 patients were carried out using UltraCision.

Two operations were carried out laparoscopically: one resection of a large liver cyst in polycystic liver disease and one segmental excision for malignant disease in the left lobe. In both operations, the ultrasound scalpel enabled a clear and hemostatic operation with minimal blood loss (<50 mL). Only the dust generated by the vaporization of tissue interfered with the laparoscopic view. There were no complications in either instance, and the patients were discharged on the days 1 and 5 after surgery, respectively. In conclusion, they clearly benefited from the laparoscopic procedure.

The ultrasound scalpel was used in 64 open liver resections in 39 patients. There were 50 segmental resections in 31 patients (22 patients with 36 liver metastases, 1 focal nodular hyperplasia [FNH], 1 hepatocellular adenoma, 3 hematomas in 2 patients, 2 hemangiomas in 1 patient, 2 hepatocellular foci in 1 patient, and 1 abscess), 4 cystectomies in 2 patients with echinococcal cysts, and 8 hemihepatectomies of the right or left lobe. In all cases the resection was performed with temporary occlusion of the portal vessels (Pringle maneuver), which never lasted longer than 40 minutes. The liver resection using the ultrasound scissors or alternatively the sickle-shaped blade allowed quick parenchymal dissection under hemostatic conditions with safe coagulation of small vessels and bile ducts. Persistent bleeding after opening the portal occlusion was treated using 4-0 polypropylene sutures. An omentoplasty was carried out in seven cases. Intraoperative blood loss averaged 820 mL (range 200–4,500); 11 patients (28%) received blood transfusions on the day of surgery. No postoperative biliary leakage or abscess was observed. After a right hemihepatectomy, one patient sustained severe bleeding on the postoperative day 1, leading to fatal liver failure after 4 weeks.

DISCUSSION

Despite standardized surgical techniques, liver resections still have a perioperative death rate of 4% to 20% and a high complication rate. ^4,8 Death and complications correlate with intraoperative blood loss, duration of surgery, and extent of intraoperative tissue damage, the latter mainly being influenced by the technique of parenchymal dissection. ^2,3 The large number of techniques used worldwide shows the lack of a generally accepted gold standard. Technical improvement seems to be possible and desirable.

The recently introduced UltraCision ultrasound scalpel represents a promising new dissection technique, at present mainly used in laparoscopic surgery and already approved here for the safe dissection of various tissues and small vessels up to 3 mm in diameter. ^11–15

The aim of the present study was to investigate the capabilities of the UltraCision instrument in liver surgery. Over a period of months, the ultrasound scalpel was used for 2 laparoscopic and 64 open liver resections. In the laparoscopic procedures, the easy handling of the ultrasound scalpel, the clear view resulting from the absence of smoke development, and the minimal blood loss resulting from the good coagulating effect were convincing. In open surgery, the ultrasound scalpel was used for different types of liver resection. Here the instrument enabled a quick and bloodless operation because of its easy handling, with excellent coagulation of the parenchyma. Smaller blood vessels and biliary tracts up to 2 to 3 mm in diameter were safely occluded. We prefer the scissors to the dissection hook because the scissors are more precise in their handling and provide a better coagulation effect. Its technical qualities mean that the ultrasound scalpel can be used as a combined instrument for blunt preparation, cutting, and coagulation in laparoscopic and open liver surgery.

Our positive experience with the ultrasound scalpel is in accordance with the reports of other authors, who used the instrument for various operations, especially in laparoscopic surgery. ^10–20 The clear view permitted by the absence of smoke and the qualities of precise preparation and adequate coagulation are principally stressed. The perioperative blood loss at the same operative speed is comparable with other resection techniques. ^16,19 The bleeding complications reported are also similar to other resection techniques. ^1–3,8

We believe the major advantage of the ultrasound scalpel is the modest trauma that it produces and the controlled dissection of the tissue. Dissection and coagulation with the ultrasound knife are achieved by local thermal denaturation resulting from the longitudinal vibration of the blade. However, thermal spreading and conduction are significantly lower compared with electrocoagulation and laser. The heat generation of monopolar and bipolar electrocoagulation and laser resection techniques is considerable by comparison and can cause thermal damage far from the plane of dissection. ⁴ Temperatures up to 82°C have been measured only centimeters away from the preparation area. ²¹ The histologic findings of tissue necrosis along the resection line ^5,16,20 are consistent with this. Infrared coagulation enables hemostasis comparable to diathermy with a depth of necrosis of 2 to 3 mm, ²² although no simultaneous tissue dissection is possible with this technique and a long contact time of 10 to 20 seconds is required. Taking into account the known correlation of the extent of intraoperative tissue damage, healing complications, and postoperative septic complications, we see here one important advantage of the ultrasound scalpel over electrocoagulation or laser techniques.

The “finger fracture” technique”¹ and the “suction knife”, ²² used for many years in our clinic for liver resections, do not provide adequate hemostasis and require the simultaneous use of titanium clips and sutures to a large extent. In contrast, smaller vessels and bile ducts up to 2 to 3 mm in diameter can be safely closed using the UltraCision scissors. The cut surface is plain and brownish; biliary leaks or persistent bleeding can easily be detected and sutured. Here we see another major advantage, explaining the small number of typical postoperative complications in our series (e.g., biliary leakage, local hematoma, or septic complications). However, larger vessels and bile ducts are divided with clamps and sutured with polypropylene in the conventional manner. The best results with the UltraCision instrument are achieved in the periphery, for example when performing a wedge resection.

The complication rate in our series was exceptionally low. This may be related to some extent to the use of the UltraCision instrument. However, other factors may play a major role, such as the use of fibrin-collagen sponges to seal the cut liver surface or the type of surgery: most operations were wedge resections, which in our experience are less prone to complications. With a greater number of hemihepatectomies, one would probably expect a higher complication rate.

Taking into account the price of the UltraCision generator ($20,000) and the single-use scissors ($250), the ultrasound scalpel is more expensive than the cheap “suction knife” or “finger fracture“ techniques. ⁸ However, especially in liver surgery, a lower complication rate in the long term easily neutralizes higher equipment costs.

The number of patients operated on with the ultrasound scalpel in this series is too small to draw any final conclusions, and the lack of homogeneity of the operations impedes statistical evaluation. Further, this was not a controlled study comparing UltraCision with other resection techniques. However, our initial experience is promising, and on consideration of these data we believe that UltraCision may become a valuable tool in liver surgery.