Efficacy of Electrocoagulation in Sealing the Cystic Artery and Cystic Duct Occluded with Only One Absorbable Clip During Laparoscopic Cholecystectomy

Abstract

Background:

Even though laparoscopic cholecystectomy (LC) emerged over 20 years ago, controversies persist with regard to the best method to ligate the cystic duct and artery. We proposed to assess the effectiveness and safety of electrocoagulation to seal the cystic artery and cystic duct after their occlusion with only one absorbable clip.

Materials and Methods:

We retrospectively compared the clinical data for 635 patients undergoing LC using electrocoagulation to seal the cystic artery and cystic duct that were occluded with only one absorbable clip (Group 1) and 728 patients undergoing LC using titanium clips (Group 2). In parallel, 30 rabbits randomized into six groups underwent cholecystectomy. After cystic duct ligation with absorbable or titanium clips, the animals were sacrificed 1, 3, or 6 months later, and intraabdominal adhesions were assessed after celiotomy.

Results:

The mean operative time was significantly shorter (41.6 versus 58.9 minutes, P<.01) in Group 1 than in Group 2. No cystic duct leaks occurred in any patients from Group 1, compared with seven leaks among the 728 (0.96%) patients from Group 2 (P<.05). The morbidity was significantly higher in Group 2 than in Group 1 (3.43% versus 1.58%). Mean intraoperative blood loss and hospitalization length were not significantly different between the two groups, and no deaths occurred in either group. In animal experiments, adhesion was tighter for absorbable than for titanium clips, but fibrous tissue encapsulation was thinner at the site of titanium clips.

Conclusions:

Electrocoagulation of the cystic artery and cystic duct that were occluded with only one absorbable clip is safe and effective during LC. This approach is associated with shortened operative times and reduced leakage, compared with the standard method using metal clips.

Introduction

Laparoscopic cholecystectomy (LC) has been accepted as the gold standard in treating benign gallbladder diseases to reduce postoperative pain, shorten hospitalization and recovery times, and decrease visible scarring.^1,2 Nevertheless, some controversies persist with regard to the best method to ligate the cystic duct and artery. Classically, metal clips are being used during laparoscopic methods for cystic duct and artery occlusion. However, many reports have described endoclip slippage and migration into the common bile duct, which may lead to stone formation as a late complication of LC.^3–5 Absorbable clips were proven to be easy to handle and to have a high reliability,⁶ and, in addition, they do not cause artifacts on subsequent computed tomography or magnetic resonance imaging scans. However, two large locking clips have usually been applied to the cystic duct and one large locking clip to the cystic artery,^7,8 leading to higher costs for patients and increased operative times. Recently, ultrasonic devices have been successfully used to close the cystic duct and artery,^9–11 but their costs remains a concern, and these approaches are not suitable for widespread use.

Our research aimed to determine whether electrocoagulation of the cystic artery and cystic duct that were occluded with only one absorbable clip during LC is a safer and more effective approach than the use of metal clips. Additionally, we used a rabbit model to compare adhesions and tissue reactivity between the surgical procedures using these two types of clips.

Materials and Methods

From November 2006 to February 2012, all patients who underwent elective or emergency LC for gallbladder polyps, acute cholecystitis and gallstones, chronic cholecystitis and gallstones, or atrophic cholecystitis in the General Surgery Department of the 117th and 322th Hospitals of the People's Liberation Army were considered. Patients were excluded if the operation was converted to an open procedure or when any other sealing devices were used. Six hundred thirty-five patients underwent LC using electrocoagulation of the cystic artery and duct that were occluded with only one absorbable clip, and 728 patients underwent LC using titanium clips for cystic artery and duct ligation. Two different surgical techniques were performed in both hospitals. Written consent was obtained from the participants. Indications for surgery included cholelithiasis confirmed ultrasonographically or by computed tomography and accompanied by severe dyspepsia or pain, previous cholecystitis, biliary pancreatitis, jaundice, and abnormal blood test results.

All participating surgeons were sufficiently trained in LC (over 300 interventions performed by each surgeon before November 2006). The absorbable clip is radiolucent and made of two components: an inner one manufactured from a polyglyconate polymer and an outer one made of a polyglycolic acid polymer. The inner track piece closes around the duct, and a rigid outer body slides over the track piece to occlude the duct. The clip has a ligating length of 12 mm, and it is applied with a reusable applicator introduced through a 10-mm port.

A uniform technique for LC was used, which involved the patient under general anesthesia and three conventional trocars (5 mm, 10 mm, and 10 mm), and a fourth 5-mm trocar was added if necessary. After the equipment was placed, the gallbladder was lifted and exposed in Calot's triangle. The relationship between the cystic duct and the common bile duct was carefully identified after examining the anatomy of Calot's triangle. The cystic duct was separated 3 mm from the common bile duct and clamped with an absorbable clip, 10 mm from the duct. One titanium clip was clamped on the gallbladder side (which subsequently was to be removed with the gallbladder later, in vitro). The cystic duct was subsequently cut between the two clips (Fig. 1). The cystic artery was isolated, and point coagulation was performed two or three times on the cystic artery with separate clamps. The coagulation time was short, and coagulation points were placed approximately 10 mm apart. The cystic artery was cut away from the common bile duct, and then it was lifted on the patient's side to perform the coagulation (Fig. 2). Calot's triangle and the gallbladder bed were separated with an electric hook. Finally, the gallbladder was removed through the subxiphoid or the infraumbilical port. Patients with unidentified cystic arteries did not undergo special treatment. Drainage suction was only rarely left in place. In the patient group using titanium clips, the difference was that after the cystic duct was isolated, it was clipped with three titanium clips, two on the patient's side and one on the gallbladder side. The cystic artery was clipped with one titanium clip on the patient's side and one on the gallbladder side during the same procedure.

FIG. 1.

The cystic duct was cut between the two clips. Only one absorbable clip was left intraabdominally.

FIG. 2.

Electrocoagulation in sealing the cystic artery with a separate clamp.

The following data were recorded: gender, age, body mass index, American Society of Anesthesiologists risk class, gallbladder disease, concomitant morbidities, operative time, intraoperative blood loss, the number of cystic arteries, the relationship between the cystic artery and Calot's triangle, postoperative mortality and morbidity, and the length of hospitalization. Cystic duct leaks were identified either on endoscopic retrograde cholangiography or at laparotomy. All analyses were performed using SPSS version 13.0 for Windows software (SPSS, Inc., Chicago, IL).

Animal experiments

Thirty 10–12-week-old rabbits, ranging in weight from 2 to 3 kg, were included in the study. All animal experiments met our Animal Protection Association guidelines. Animals were randomized into six different groups prior to the initial surgical procedure: three control and three experimental groups, each containing five rabbits. Titanium surgical clips were used in the control groups to ligate the cystic duct and artery, and absorbable clips were used in the experimental groups. Animals were sacrificed at 1, 3, or 6 months, a celiotomy was performed after injection of pentobarbital (30 mg/kg) intravenously, and the intraabdominal adhesions were assessed and scored as follows¹²: 0, none; 1, filmy, avascular; 2, dense or vascular; and 3, dense and vascular.

Results

The patients' characteristics, including gender, age, body mass index, American Society of Anesthesiologists status, distribution of diseases, and comorbidities, were well matched between the two groups, without any statistically relevant differences (Table 1). Details of the operative course were evaluated in the two groups (Table 2). The mean operative time was significantly shorter in Group 1 than in Group 2 (41.6 versus 58.9 minutes). The mean intraoperative blood loss and the length of hospitalization were not significantly different between the two groups. The mean hospital stay was short, as expected, and well matched between the two groups. The number of cystic arteries and the relationship between the cystic artery and Calot's triangle were not significantly different between the two groups.

Table 1.

Patients and Disease Factors in 1363 Laparoscopic Cholecystectomies

Characteristic	Group 1	Group 2
Sex
Female	379	434
Male	256	294
Mean age (years)	42.2±13. 6	43.1±12. 5
BMI (kg/m²)	23.8±1.8	23.9±1. 5
ASA score (1/2/3)	98/375/162	112/428/188
Disease
Gallbladder polyps	90	102
Acute cholecystitis and gallstone	278	317
Chronic cholecystitis and gallstone	218	251
Atrophic cholecystitis	49	58
Comorbidity (%)	256 (40.3)	287 (39.4)
Pulmonary	32 (5.04)	35 (4.81)
Cardiovascular	141 (22.2)	157 (21.6)
Diabetes	45 (7.09)	50 (6.87)
Liver dysfunction	38 (5.98)	43 (5.91)

ASA, American Society of Anesthesiologists; BMI, body mass index.

Table 2.

Details of the Operative Course

	Group 1	Group 2
Mean operative time (minutes)	41.6±16.5^a	58.9±19.4
Mean intraoperative blood loss (ml)	12.2±0.8	11.9±0.7
Mean hospital stay (days)	2.6±0.4	2.7±0.6
Calot's triangle
Within	619	711
Outside	16	17
Adhesion	5	6
Number of arteries
None	6	6
One	546	624
Two	72	86
Uncertain	11	12

P<.01 versus Group 2.

No perioperative deaths occurred in either group, and the overall morbidity rate was 1.58% (10/635) in Group 1 compared with 3.43% (25/728) in Group 2. Morbidity in Group 2 was significantly higher than in Group 1 (P<.05). The details of postoperative complications are shown in Table 3. A cystic duct leak occurred in 7 (0.96%) of the 728 patients in Group 2, compared with none (0 %) of the 635 patients in Group 1 (P<.05). All cystic duct leaks in patients with biliary peritonitis were treated at the time of the laparotomy. The rate of significant postoperative bleeding that necessitated reoperation was low (2 patients in Group 2), and the reasons involved bleeding from the hepatic gallbladder bed. In none of the patients undergoing reoperation was the severe postoperative bleeding a consequence of clip failure. Minor wound infections at the umbilical trocar site occurred in 1 patient from Group 1 and in 2 patients from Group 2, a difference that was not statistically significant.

Table 3.

Postoperative Complications

Complication	Group 1	Group 2
Cystic duct leak rate	0	7 (0.96)^a
Wound infection	1 (0.16)	2 (0.28)
Pancreatitis	2 (0.32)	3 (0.41)
Ileus	3 (0.47)	4 (0.55)
Lung atelectasis	3 (0.47)	3 (0.41)
Bleeding	0	2 (0.28)
Port hernia	0	2 (0.28)
Abdominal abscess	1 (0.16)	2 (0.28)
Total	10 (1.58)	25 (3.43)^a

Data are percentages.

P<.05, versus Group 1 for this complication.

Animal experiments

All clips, either titanium or absorbable ones, were applied without difficulty, and no complications arose during the experiments. Furthermore, there was no evidence of postoperative bleeding and bile leakage in either the control or the experimental groups. Intraabdominal adhesions and fibrous tissue formation were used to assess tissue reactivity in vivo to both types of surgical clips. Upon controlling for this factor, we observed that adhesions were tighter in the absorbable clip group than in the titanium clip group in 1, 3, or 6 months. However, at all stages, fibrous tissue encapsulation was thinner at the site of titanium clips than at the site of absorbable clips. After 6 months, we observed tan tissue deposition around the titanium clips, but the absorbable clips degraded by hydrolysis and left only a fibrous tissue scar.

Discussion

After the introduction of laparoscopic LC in 1986 and a quarter century of training, this approach has rapidly become the gold standard for gallbladder removal.¹³ This operation is considered to be very effective and safe. Currently, the risk of many types of complications, such as bile duct and bowel injuries, postoperative bile leaks, and hemorrhage, has been significantly reduced in the hands of well-trained laparoscopists.

Nevertheless, some controversies remain with regard to the best method to ligate the cystic duct and artery. Traditionally, the application of metal clips is the most popular method of securing the cystic duct and artery during the procedure, but the foreign body dwelling in the abdomen after surgery may lead to many complications that have been increasingly reported. The imaging properties of metallic clips on computed tomography and magnetic resonance imaging have been extensively studied and were shown to be associated with significant distortion and image artifacts.^14,15 Cystic duct leaks may cause the inadequate closure of the duct, necrosis of the duct at the clipping site, slippage of the clips off the end of the duct,¹⁶ or laceration of the cystic duct.¹⁷ Besides, the metal clips may conduct electricity, causing a cut in the cystic duct.¹⁸ Clips can also cause the occlusion and stenosis of the common bile duct without causing any lacerations.¹⁹ Furthermore, the metal clips can erode the cystic duct and migrate into the common bile duct.³ A clip that migrated in this manner may act as a nidus for stone formation in the common bile duct.^4,5 In contrast, locking absorbable clips come as part of a disposable cartridge and are easy to use and apply.²⁰ They consist of an outer rigid body of polyglycolic acid that slides over a soft pliable polyglyconate inner clip. Once applied, these clips are not easily dislodged. These polymeric absorbable clips are degraded by hydrolysis within 6 months, and this might help avoid the complications mentioned above.

Recently, ultrasonic dissectors have been used to occlude the cystic duct and artery.^9–11 Nevertheless, these are considered expensive, and they are not widely used during LC. This study evaluated the application of polymeric absorbable surgical clips and cystic artery electrocoagulation to LC. Our results showed that the mean operative time was significantly shorter with absorbable clips than with titanium clips. No cystic duct leaks occurred in any participants from the absorbable clip group, compared with seven leaks that occurred in the 728 participants to the titanium clip group. The morbidity in the titanium clip group was significantly higher than that in the absorbable clip group. The mean intraoperative blood loss and hospital stay were not significantly different between the two groups, and no deaths occurred in either group. The animal experiments revealed that adhesions in the absorbable clip group were tighter than in the titanium clip group. However, fibrous tissue encapsulation at the site of titanium clips was thinner than at the site of absorbable clips. After 6 months, we observed tan tissue deposition around the titanium clips, but the absorbable clips were degraded by hydrolysis and only left fibrous tissue scars.

The safety of using the electrocautery alone to divide the cystic artery has been questioned because the anatomic variations in and around Calot's triangle are frequent. Electrocoagulation of the cystic artery may cause collateral tissue injury or may not be adequate to seal the artery. Katri et al.²¹ proved that after accurately identifying the anatomy of the cystic artery, electrocoagulation is safe and effective to control the cystic artery during LC. In our experience, the crucial steps during cystic artery electrocoagulation are to carefully dissect the gallbladder triangle, discern the relationship between the cystic duct and the common bile duct, and apply the cautery very close to the gallbladder, preferably laterally from the cystic lymph nodes. The cystic artery is coagulated at two or three different time points with separate clamps. The coagulation time is short, the procedure is performed two to three times at every point, and the length between the coagulation points is approximately 10 mm. The cystic artery is cut away from the common bile duct, and it is subsequently lifted on the patient's side to perform the coagulation. When coagulating the gallbladder artery, it is important to pay attention to use the appropriate traction force, and the separation clamp should not be in contact with the liver or with other structures.

In conclusion, during LC using electrocoagulation of the cystic artery, occlusion of the cystic duct with only one absorbable clip is safer and more effective than with metal clips. In addition to simplifying the surgical intervention, shortening the operative time, and reducing the medical costs, the avoidance of metal clips also prevents slippage, migration, and other complications that may occur. Moreover, no artifacts are created on subsequent computed tomography or magnetic resonance imaging scans.

Footnotes

Acknowledgments

This project was funded by the 117th Hospital of the People's Liberation Army (grant YG001). We greatly appreciate the support.

Disclosure Statement

No competing financial interests exist.

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