A Prospective,Randomized Study of Comparison of Clipless Cholecystectomy with Conventional Laparoscopic Cholecystectomy

Introduction

Cholecystectomy for gallstone disease presently accounts for a large share of laparoscopic procedures being done worldwide. Laparoscopic technique for performing cholecystectomy is now the gold standard treatment for gallstone disease. ¹ Being a commonly performed surgery, laparoscopic cholecystectomy is undergoing a thorough makeover with the incorporation of newer technologies.

Use of ultrasonic shears in laparoscopic cholecystectomy provides the surgeon with newer possibilities in laparoscopic cholecystectomy. Ultrasonic shears adequately seal the lumen and keep the surgeon free from fear of clip slippage and other clip-related complications. Minimum bleeding while dissection provides clear surgical fields and reduced postoperative morbidity. The scepticism still exists in using ultrasonic shears as the sole instrument for laparoscopic cholecystectomy. Various studies have reported that cystic duct and artery can be safely ligated using the ultrasonically activated shears.^2–6 In studies wherein bile leak was appreciable, the rates of leak were comparable in the two groups and ranged from 2% to 4%.

Among the various studies that have testified the use of ultrasonic shears in laparoscopic cholecystectomy, all benefits of using this device could not be appreciated, because of either a small sample size or comparison of only a few parameters in these studies. The fear of use and hesitancy still persists regarding widespread acceptance of clipless cholecystectomy because of lack of randomized, controlled trials in this subject. This prospective, randomized, controlled trial aims to provide better understanding to dispel fear and encourage use as a sole device for performing the procedure.

Materials and Methods

A prospective, randomized, control study was undertaken in the Department of Surgery, Maulana Azad Medical College, and associated Lok Nayak Hospital, wherein 200 patients with symptomatic gallstone disease undergoing laparoscopic cholecystectomy between 18 and 70 years of age were included if they did not fall in the exclusion criteria. These patients were randomly divided into two groups using a computer-generated software, one undergoing surgery with electrocautery (group A) and the other with ultrasonic shears (group B). Exclusion criteria included the following:

Appropriate clearance from the scientific and ethical committee of the institution was obtained before starting the study.

A detailed informed consent was obtained from all patients. All patients were given the option to opt out of the study at any stage without compromising their right for treatment. Laparoscopic cholecystectomy was performed using the four-port American technique. In group B patients, after dissecting the Calots triangle with ultrasonic shears, ligation of the cystic artery and duct was done by ultrasonic shears at the power setting of 2, and shears were not removed till the two ligated ends gave way on their own. Before ligation of cystic duct with ultrasonic shears, the size of the cystic duct was judged by comparing it with the size of CBD. To do this, first the width of CBD was judged by opening the jaws of harmonic shear and then compared with the width of cystic duct. In none of our patients, the width of cystic was found to be more than the width of CBD and we did not include any patient with CBD size >5 mm. The surgeons assessed the cystic duct for any calculi before cutting by moving the jaws of ultrasonic scalpel up and down the duct. The jaws were placed at a safe distance from the CBD to avoid injury to it. The instrument was then activated after fixing the jaws and keeping the instrument still till the two ends got separated at their own without applying traction.

Dissection of the gallbladder liver bed was also done using ultrasonic shears at a setting of 5, with minimal bleed. The gallbladder was extracted from the epigastric port and drains were inserted whenever there was significant bleed, ooze from the gallbladder fossa, or bile spillage due to gallbladder perforation. Patients undergoing conventional cholecystectomy in group A underwent dissection with Maryland's dissector and cystic duct and artery were ligated using clips. The gallbladder was extracted from the gallbladder bed using hook and electrocautery. Intraoperatively the time of surgery (starting from skin incision to closure) and the time taken to remove the gallbladder from the gallbladder bed were noted. Postoperative pain scores using visual analog score and analgesic requirement were noted at 6 hours following surgery and at days 1 and 2 by an observer who was unaware of the procedure performed, to eliminate observation bias. Postoperative complications if any and duration of stay were noted. Gallbladder perforation and need for placement of drains were also noted. The amount of blood loss was adjudged by the fall in hemoglobin and hematocrit on postoperative day 1. Patients were followed up at 1 and 3 weeks and at end of 6 months following surgery for completion of data regarding pain score, consumption of analgesics, and complications of surgery if any.

Results

One hundred patients were included in each group for the study. Four patients in each group were converted to open cholecystectomy and thus they were excluded from the study. Both the groups were found to be comparable on data analysis in terms of demographic variables (Table 1) and complicating factors to surgery such as incidence of previous surgery and number of calculi.

The efficacy of the device was compared with electrocautery by taking into account the duration of surgery, which was 50.00 ± 9.35 minutes with ultrasonic shears compared with 64.70 ± 13.74 minutes with electrocautery, and the time to remove gallbladder from its bed, which was nearly 4 minutes when ultrasonic shears were used versus 7.36 minutes when electrocautery was employed. Both these times were significantly less on using ultrasonically activated scalpel (P value of .001). The results of our study have been summarized in Table 2.

Various factors that complicate laparoscopic cholecystectomy, such as gallbladder perforation, were also significantly less in the ultrasonic shears group (9 versus 18; P value of .002). There was also decreased need of placement of drains after the gallbladder was removed (12 versus 31; P value of .002).

Efficacy of dissection was judged by blood loss and postoperative pain. There was greater fall in hemoglobin (0.53 versus 1.33 g%; P value of .001) and hematocrit (1.59 versus 2.60; P value of .001) when electrocautery was used.

Postoperative pain scores were significantly reduced on day 0 (2.65 versus 4.58; P value of .001) and day 1 (1.86 versus 3.01; P value of .001). However, scores at postoperative weeks 1 and 3 were comparable (Fig. 1). Analgesic requirement was reduced significantly only on day 1 (1.89 versus 2.66; P value of .001). Amount of analgesics consumed was comparable on day 0 and at 1st and 3rd weeks. There was no incidence of any major complication such as bile leak, peritonitis, or bowel injury in any of the patient. In 8 patients (4 belonging to group A and 4 belonging to group B), the procedure was converted to open because of difficult anatomy of the Calots triangle.

OPEN IN VIEWER

FIG. 1.

Comparison of pain scores.

Discussion

The present study, which is a prospective, randomized, control trial, clearly shows the safety and superiority of ultrasonically activated scalpel in laparoscopic cholecystectomy in terms of dissection and sealing of cystic artery and duct without any increase in intraoperative and postoperative complications. We have used ultrasonic shears as the only instrument in dissection of calots triangle, ligation of cystic duct and artery, and removal of gallbladder from its bed, without the use of clips and electrocautery. The study shows decreased postoperative pain and analgesic requirement and shorter hospital stay with the use of ultrasonic scalpel.

The ultrasonically activated scalpel is a technological marvel that has a cutting and coagulation effect similar to electrocautery but is devoid of many harmful effects that occur because of the lateral spread of electric current. The transfer of mechanical energy breaks the tertiary hydrogen bonds in the tissues and generates heat from internal cellular friction. Coaptation of vessels by tamponading occurs along with sealing by denatured protein coagulum. Vibrating protein further produces secondary heating, which seals larger coapted vessels.

Heat, pressure, and turbulence generate bubbles in tissues with high water content, leading to disruption. Ultrasonic shears generate temperatures ranging from 80°C to 100°C, compared with 200°C or more with conventional electrocautery. The depth of penetration of ultrasonically generated heat is nearly 1.5 mm, which reduces the chances of injury to important structures such as bile ducts and arteries. ² Shears can be effectively used for dissection of Calots triangle, ligation of cystic duct and artery, and removal of the gallbladder from liver bed,^3–9 making it an all in one tool for the procedure. This minimizes not only the operating time but also inadvertent injury to the viscera occurring during instrument change. ¹⁰ There is decreased postoperative adhesion formation and early return to normal activity. This added to decreased postoperative pain, ¹¹ ease of surgery, and decreased risk of operative and postoperative complications makes the ultrasonically activated scalpel the instrument of choice.

For long, traction has been used by surgeons as an important tool of dissection to separate out tissue in their physiological planes. This method remains time tested and trusted and is now incorporated in ultrasonic shears to divide tissue in its natural planes as much as possible. The fine movement of the active blade, which is nearly 60–150 μm, pulls the tissue with it removing it from the underlying planes by means of gentle consistent traction. At the same time, the vibration at 55,000 Hz produces heat due to friction in the order of 60–100°C, which denatures the proteins by breaking their tertiary structure and causing coagulum to form rather than charring and carbonization that is produced on using heat energy from cautery or lasers.

The ultrasonic energy also produces small vacuoles or cavitations that enlarge and separate tissues. The device, therefore, makes it easy to separate the gallbladder from the gallbladder bed to which it is adherent by means of flimsy fibrous tissue. In the event of inflammation, this flimsy tissue undergoes edema and infiltration by fibrocytes and macrophages, leading to the formation of a tougher and more fibrous, adherent bond between the two organs.

In the present study, fall in hemoglobin and hematocrit levels was statistically much less in the ultrasonic shear group in comparison to the electrocautery group. Decreased fall in hemoglobin and hematocrit levels signifies less blood loss. Less blood loss in ultrasonic group can be explained by the fact that harmonic scalpel can differentiate between natural tissue planes and inflammatory planes. Harmonic scalpel performs dissection in natural tissue planes if proper traction is maintained between the gallbladder and its bed.

In the present study, the duration of hospital stay was found to be statistically significantly less in the ultrasonic group compared with the electrocautery group. Shorter duration was attributable to less number of patients requiring placement of drains and thus the patients could be discharged earlier. The patients who had drains were discharged only after removal of the drain. Less number of patients in the ultrasonic scalpel group had gallbladder perforation during dissection from the gallbladder bed. Perforation of gallbladder leads to spillage of bile and localized peritonitis despite best efforts to wash it away. Localized peritonitis leads to increased pain, leading to delay in discharge.

The chronic cholecystitis cases presented a peculiar picture wherein ultrasonic shears could differentiate the planes between the gallbladder and liver unlike electrocautery, which could not differentiate between virgin and postinflammatory fibrosed tissue. As described in various studies by Amaral, ⁹ who did pioneering work in ultrasonic scalpel use, this device has a hemostatic effect combined with ability to dissect in between tissue planes, making it a suitable instrument to replace electrocautery in laparoscopic cholecystectomy. Amaral did over six studies on the subject and was one of the initial few to study its usefulness in this procedure.

The mean duration was 50 minutes and 10 seconds when we used ultrasonic shears compared with 64 minutes and 56 seconds when electrocautery was used to dissect. We gained 14 minutes and 46 seconds on an average by using this device. The dissection defines the plane easily for further dissection, making the whole process much easier and cleaner.

Our study compared the time to remove gallbladder from its bed using both the methods and we found that it took an average time of 4 minutes to remove the gallbladder using ultrasonic shears compared with an average time of 7½ minutes using electrocautery. Other reasons of less operating time with ultrasonic scalpel are reduced need of instrument exchange. Ultrasonic shears can be replaced for dissection, cutting, and ligation, which means that the instruments such as Maryland's dissector, electrosurgical hook, clip applier, and shears can all be kept at bay. The shears have two blades, of which one longitudinally moves over the other fixed blade, which is a part of the instruments body.

The tissue to be dissected needs to be placed in between these two blades. The blades are useful for gripping as well as dissecting and ligating. The Calots triangle, which is essentially made up of fat and peritoneal folds and covers the cystic duct and artery, could be safely approached with ultrasonic shears. In all patients of the ultrasonic scalpel group, the cystic artery was ligated using the ultrasonic scalpel at a power setting of 2. We observed no complications postoperatively in these patients. Cystic duct was also ligated in all cases at a power setting of 2. When minimal power settings are used, tissues with high strength are disrupted as suggested by Hodgson et al. ¹² It is only at the maximum power mode that the tissues are cut without distinction. The vessels are sealed side by side and there is minimal bleed.

In studies on ultrasonic shears, such as those by Bessa et al ¹⁰ and Westervelt, ³ the harmonic ACE was used for dissection in the triangle of Calots with power level set at 5, which causes more cutting and less coagulation. For the closure and division of the cystic duct and artery, the instrument was set at the power level of 2, which gave a more sustained coagulation effect and a less cutting effect.

The effects of electrocautery spread laterally up to 0.5 cm, whereas with ultrasonic shears the lateral spread of energy is only up to 1.5 mm of the cutting edge as observed under microscope by Hüscher et al. ⁵ Minimal spread to surroundings decreases the chances of gallbladder perforation, spillage of gallstone and bile, and biliary peritonitis. During dissection, we observed that keeping the gallbladder intact was very helpful in performing a clean and faster surgery. After spillage, there is disproportionate increase in duration of surgery. Bessa et al. ¹⁰ stated that surgical time significantly increase in the presence of gallbladder perforation, be it done by ultrasonic shears or electrocautery. In our study, the incidence of perforation of gallbladder was much less than in the ultrasonic group in comparison to the electrocautery group (9 versus 18). The increased gallbladder perforation is another factor attributable to the increase in the duration of surgery. Biliary spillage calls for more irrigation and suctioning and also leads to spread of infected contents into the rest of the abdomen. It also contributes to a poor field and visibility.

Ultrasonic shears generate only mist by vibration, which allows the surgeon to work in a clear field throughout the procedure. This gives advantage in terms of operating time and decreased risk of accidents due to poor visibility and instrument change.

The ligation of cystic duct till date is surrounded by scepticism. Fullum et al. ¹³ and Cengiz et al., ¹⁴ who used ultrasonic shears for dome-down cholecystectomy, used ultrasonic scalpel only for ducts less than 6 mm. Vu et al. ¹⁵ published their work with a recommendation that ultrasonic shears can effectively ligate cystic duct up to 6 mm in diameter. In our patients, the cystic duct and CBD status were confirmed preoperatively by ultrasonography. The CBD less than 6 mm was reported as normal in caliber. The cystic duct was intraoperatively compared with the CBD before ligating.

As ultrasonic shears coagulate what they cut and stay between the planes, there is decreased bleeding and oozing from the surfaces. Other complications such as bile leak, stone spillage, and gallbladder perforations are also less. This kept us confident of the procedure and we had to put less number of drains in patients who underwent laparoscopic cholecystectomy by ultrasonic shears (12 versus 31). The decreased incidence of drain placement further manifested itself in the form of less pain scores, early discharge, and decreased morbidity.

Drains are usually placed when the operating surgeon feels that chances of continuous ooze or bleed exist or when he suspects biliary injury or leak. In such cases, drains can decrease the morbidity by effectively bringing out the contents and preventing stasis and infection. When peritoneal contamination is less, the need is obviated. This is another of the many factors that decrease surgical time and, more importantly, morbidity. We placed drains in all cases with gallbladder perforation and spillage of bile and stones and in patients in whom there was suboptimal hemostasis in the gallbladder fossa after removing the gallbladder. The drains were removed only when the output was less than 30 mL without the presence of bile in it. In all cases, we were able to remove the drain within 48 hours. There were no complications associated with the placement of drains.

The causes of pain after laparoscopy were studied by Alexander in 1997, ¹⁶ who attributed the major cause of pain to be rapid distension of the peritoneum, which causes tearing of vessels, traumatic traction to the nerves, and release of inflammatory mediators. For the prolonged persistence of shoulder tip pain, irritation of phrenic nerve has been pointed out as the causative factor, for which some surgeons have tried active aspiration of gas bubble under the diaphragm or use of “Gas Drain” ¹⁷ or local anesthetic instillation.

We observed a significant reduction of pain scores in our study when ultrasonic shears were used for the procedure. The pain scores on both days 0 and 1 were lower than that of the electrocautery group. Pain during these 2 days has different pathophysiology. Pain on day 0 was due to visceral irritation, which peaked at about 24 hours. It then waned down to recur at later days and was taken over by parietal pain at the sites of trocar insertion and incision. A reason to this is minimal collateral thermal damage. There is minimal damage to surrounding nerves and minimal charring, thereby producing less inflammation and controlled release of inflammatory mediators. Involvement of nerve bundles has been studied microscopically by Hüscher et al. ² Pneumoperitoneum-related peritoneal distension and neuronal rupture may not be reduced with use of ultrasonic shears, but as the duration of surgery is reduced, it may directly affect the degree and duration of peritoneal distension, thereby accounting for lower pain scores. Inflammation, which is the other cause of postoperative pain, was definitely reduced because of minimal lateral damage to surrounding tissues and nerve.

Pain on the day following surgery predominantly arose from the site of trocar insertion and incision. Shoulder pain, which occurred following phrenic nerve excitation, was also predominant on the second day. Although parietal pain was not much affected and responds well to nonsteroidal anti-inflammatory agents, the shoulder tip pain was typically bothersome to the patients. This component of pain was decreased when ultrasonic shears were used, because there was decreased incidence of biliary leak, spread of inflammatory mediators, and need for irrigation and suctioning. Pain response in our study was predictable and significant difference in pain scores was obtained between the two groups on postoperative days 0 and 1.

No significant differences were obtained in the pain scores at weeks 1 and 3. Analgesic requirement was less in the postoperative period in the ultrasonic shears group compared with the electrocautery group.

Our study results are in concurrence with the research done worldwide that ultrasonic shears have a definitive edge over electrocautery in terms of ease of surgery, faster operating time, ability to handle difficult situations, and above all, its safety. Ultrasonic shears were used in our study as a sole instrument to perform the procedure involving dissection and removal of the gallbladder from the gallbladder bed without any problems. There was less risk of injury to surrounding structures and the procedure was followed by no postoperative complications.

In the postoperative period, pain scores were favorable and analgesic requirements were less. The patients were discharged early because of less pain and morbidity. The patients were followed up for 3 weeks without any complications.

We thus add to the benefits of using ultrasonic shears to perform a clipless cholecystectomy, which not only is limited to a faster and safer surgery but also provides other benefits to the surgeon, such as clear operating fields, avoidance of multiple instrument change, and decreased risk of complications, thus reducing the surgical fatigue. On the other hand, it also benefits the patient not just by means of a safer procedure but also in terms of decreased pain and morbidity, a faster recovery, and decreased hospital stay.

Conclusions

Ultrasonically activated scalpel can be used safely in laparoscopic cholecystectomy without risk of major injuries or leaks. It fairs better than electrocautery in terms of not just a faster and safer surgery but also a surgery with decreased associated morbidity and pain and early return back home.