A New Exploration for Gallbladder Polyps: Gallbladder Polypectomy by Endolap Technique

Introduction

Gallbladder polyps are more commonly detected in East Asia countries and affect 8.9% of the adult population there. ¹ Clinically, polyps exceeding 1 cm in diameter may be malignant and are often treated with different types of cholecystectomy, ² such as laparoscopic cholecystectomy and single-incisional laparoscopic surgery, which can result in bile duct injury, postcholecystectomy syndrome, or other serious complications during and after the operation.^3–5 Moreover, the majority of gallbladder polyps exceeding 1 cm are benign polyps, such as cholesterol polyps.

Therefore, the first step in the treatment of gallbladder polyps is precise diagnosis. Recently, it was shown that an accurate diagnosis can be obtained with multidetector computed tomography combined with high-resolution ultrasonography, ⁶ although endoscopic biopsy remains the standard for obtaining a precise diagnosis.

With the realization of the importance of gallbladder function, many specialists are increasingly advocating for conservation of the gallbladder in the setting of benign lesions. In 1994, we proposed that if polyps were benign and gallbladder function was well preserved, there was no absolute indication for gallbladder removal. ⁷ In 2004, we reported our serial cases of percutaneous endoscopic polypectomy of the gallbladder. ⁸ The two procedures were safe, and there was no recurrence of polyps. Moreover, the follow-up showed good preservation of gallbladder function. However, these approaches are limited to some patients. ⁹ With the development of laparoscopic and endoscopic techniques, we have attempted to improve the operation. Compared with previous studies, we have improved the operation to a new endoscopic–laparoscopic (Endolap) technique.

Our latest data manifested an incentivizing result and suggested that the Endolap technique was more effective for managing gallbladder polyps. Combined with sufficient preoperative assessment and evaluation of gallbladder function, we performed Endolap polypectomy in 60 patients. This article describes our technique and its reliable results.

Patients and Methods

Operative procedures

Endolap polypectomy of the gallbladder was performed with the patient under general anesthesia. Patients were placed in the reverse Trendelenburg position, and the operating table was tilted upward to the right. After pneumoperitoneum was achieved, a 10-mm trocar was inserted through the umbilicus, and then the 30° laparoscope was introduced to inspect the peritoneal cavity adhesions and the appearance of the gallbladder. Then, a 10-mm trocar and two 5-mm trocars were placed on the right subcostal, the left subcostal, and the right midclavicular line lateral to the umbilicus, respectively (Fig. 1A). A piece of dry gauze was placed around the gallbladder. A 5-mm incision was made on the gallbladder fundus with the electronic hook, and bile was withdrawn (Fig. 1B). The gallbladder lumen was irrigated with saline; meanwhile, the soft choledochoscope was introduced to inspect the inner wall through the right subcostal trocar (Fig. 1C).

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FIG. 1.

The first part of the operation procedure. (A) The trocar site. (B) A 5-mm incision was made on the gallbladder fundus. (C) The gallbladder polyp was located using the soft choledochoscope. (D) The polyp was discovered using the soft choledochoscope.

Through the soft choledochoscope, the bipolar flexible microwave thermal antenna was inserted into the gallbladder. For pedunculated polyps, the polyp stem was coagulated directly (Fig. 2A); for sessile polyps, coagulation was performed along the basement of the polyps, along with simultaneous irrigation with nephrine saline (1:1000 dilution). Then, each polyp was removed using a biopsy clamp for histological examination (Fig. 2B). The gallbladder was rinsed once again, and the choledochoscope was placed to ensure reflux from the opening site of the cystic duct. After the patency of the cystic duct, a lack of bleeding, and no residual polyps were confirmed, the incision on the gallbladder fundus was sutured using an absorbable 4/0 polyglactin 910 (Vicryl™ Plus; Ethicon, Somerville, NJ) (Fig. 2C). ¹¹ In the first 20 patients, full-thickness closure of the incision was performed. In the latter 40 patients, we improved to close the incision with a double suture: the mucous membrane and then the muscular layer as well as the serous membrane. After no active bleeding or bile leakage was identified, the gauze was removed, and the operative field was irrigated repeatedly. No drainage was placed. The trocars were removed, and the ports were closed with stitches. The patients usually resumed eating after 24 hours of postoperative fasting.

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FIG. 2.

The second part of the operation procedure. (A) The polyp stem was coagulated directly using the flexible coaxial bipolar microwave antenna. (B) The polyp was removed using a biopsy clamp. (C) Continuous suturing of the mucous membrane was performed. (D) The cholesterol polyp.

Results

The security of the microwave

Microwaves generated at 50–70 mA for 9 seconds produced effective mucosa coagulation. The gallbladder mucosa of pigs was coagulated using the coaxial bipolar microwave antenna (Fig. 3B). Then, 1 week later, the gallbladder epithelial cells started to regenerate on the surface of the coagulated mucosa (Fig. 3C); 2 weeks later, the gallbladder mucosa was almost normal (Fig. 3D). All images suggested that the gallbladder mucosa is self-healing and can recover to normal after injury. Thus, endoscopic polypectomy using microwave coagulation was feasible in patients.

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FIG. 3.

Electron micrographs show the healing procedure of the pig gallbladder mucosa coagulated with the coaxial bipolar microwave antenna. (A) Normal gallbladder mucosa. (B) The gallbladder mucosa coagulated. (C) Gallbladder epithelial cells began to regenerate 1 week later. (D) Gallbladder epithelial cells have almost covered the coagulated area 2 weeks later.

Follow-up

A long-term follow-up for a mean of 1.5 years (range, 0.5–2.5 years) was carried out in 56 cases, and the follow-up rate was 100%. The results showed that all patients were symptom free. Polyps did not recur. The volume and contractility of the gallbladder based on ultrasonography were found to be well preserved. Different closures for the gallbladder fundus incision slightly interfered with the volume and the contractility of the gallbladder (Fig. 4). The volume and contractility were decreased at 1 month after the operation and elevated at 3 and 6 months after the operation.

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FIG. 4.

The contraction and volume of the gallbladder followed up 1, 3, and 6 months after the procedures. (A) Compared with preoperatively, the contraction produced by the full-thickness suture and the double suture was reduced 1 month after the operation but increased to almost normal 3 months after the operation and was maintained. (B) The gallbladder volume recovered to 84.26% of the preoperative volume in the full-thickness suture group and 92.67% in the double suture group 6 months after the operation.

Discussion

The incidence of the gallbladder polyps is high in East Asian countries. Most gallbladder polyps histologically are cholesterol polyps, whereas the minority of the polyps include inflammatory polyps, adenomyomatosis, adenomas, and others. ¹² In our study, cholesterol polyps accounted for 91.07% (51/56) of the polyps detected, and the gallbladder function in these cases was good. The gallbladder is a vital organ of the human body, and its function includes not only the storage, concentration, and excretion of bile during feeding, but also the regulation of intrahepatic and extrahepatic bile duct pressure. There are also important secretion and immune functions. Based on the importance of gallbladder function, it is very necessary to select a more suitable operation for benign polyps. For this reason, we first developed a percutaneous endoscopic polypectomy technique in 1994. ⁷ Our past data in 2004 showed a progressive result that 78.8% of the operative patients were followed up over 5.5 years on average, and 95% of the cases had a good gallbladder function without gallstone formation and polyp recurrence. ⁸ Our present study also demonstrated that polypectomy of the gallbladder polyps is a reliable and effective procedure. ¹³

As a minimally invasive technique, percutaneous cholecystoscopy can facilitate the correct diagnosis through endoscopy and adequate biopsy using a coaxial bipolar microwave antenna for the removal of polyps and preservation of the gallbladder with satisfactory results. Since 1994, we have explored percutaneous endoscopic polypectomy for gallbladder polyps. Because of the physical limitations of the hard choledochoscope, the entire gallbladder lumen and gallbladder mucosa were difficult to clearly inspect. With the development of the soft choledochoscope, which we used instead of the hard choledochoscope, this problem was solved, and better outcomes were obtained. In 2004, ⁸ we published our improved procedure and follow-up results. However, in some patients who are obese or whose gallbladder is situated in an abnormal position, percutaneous procedures cannot be performed.

As the laparoscopic technique has become popular, we have modified the laparoscope by combining with a choledochoscope technique, which can be performed for nearly all patients. All procedures were uneventful with an operating time between 60 and 135 minutes, except for 4 patients who were not suitable for gallbladder preservation. In this series, there were 12 patients with a body mass index of >35 kg/m², and their gallbladder fundus was not situated in the subcostal region; as a result, percutaneous cholecystoscopic procedures could not be performed.

Although obesity is associated with a higher incidence of gallbladder disease with increasing body mass index, ¹⁴ percutaneous endoscopic polypectomy is inappropriate in obese patients. Moreover, the higher the index, the greater the difficulty of performing any type of cholecystectomy becomes. Some studies have reported that a body mass index exceeding 30 kg/m² increases the difficulty of the operation and that a body mass index exceeding 35 kg/m² increases not only the wound infection rate but also the conversion rate, possibly because of the abnormal anatomy and the difficult separation of the structures, especially in Calot's triangle. ¹⁵ The Endolap technique avoids these risks, enables the gallbladder fundus to be manipulated in situ, and also has wider indications for gallbladder manipulation. All followed-up patients were symptom-free and without recurrence of polyps. Their gallbladder function recovered to the normal level 3 months after the operation. In contrast to the new technique, percutaneous endoscopic polypectomy can be a basic technique for training residents.

Currently, controversy in the management of asymptomatic patients with gallbladder polyps still exists. Therapeutic decision-making is usually correlated with the polyp size and shape. ² Based on the literature, for the following findings, cholecystectomy was recommended: (1) polyps of 10 mm or more in diameter; (2) sessile polyps associated with stones in patients older than 50 years; and (3) symptomatic polyps. However, the diagnostic criteria for cholecystectomy remain a challenge. In this study, polyps larger than 10 mm were present in 11 cases, but only 2 cases were adenomas. In our patients, most of the polyps were detected on routine examination, and patients were usually given unclear information about the polyps, which always caused them to be afraid of malignancy of the polyps and to suffer some mental stress. In 1994, we reported one adenoma treated with percutaneous polypectomy. ⁷ To date, no recurrence or malignancy has occurred. To the best of our knowledge, if polyps are benign and the gallbladder function is normal, polypectomy with gallbladder preservation should be considered. However, we recommend cholecystectomy for the following cases: more than three polyps of the gallbladder, adenomyomatosis of the gallbladder, intramural gallstones, or more than three gallbladder stones. If stones were discovered by chance and there were fewer than three, we recommend removal of the polyps and stones and subsequent preservation of the gallbladder.

Gallbladder volume is an important parameter of gallbladder function. The size of a stab incision in the gallbladder fundus and the closure method could affect gallbladder function. In this study, the incision on the fundus was less than 1 cm, and double-layer sutures (mucous to mucous, seromuscular to seromuscular) influenced the gallbladder volume and contractility to a lesser extent. In the full-thickness suture group, the volume and contractility of the gallbladder at 1 and 3 months after the operation seem to be lower than those of the double-layer suture group. This observation implies that sophisticated laparoscopic suture skills are needed for gallbladder preservation. In addition, absorbable sutures are recommended, and the tissue should not be stitched extensively.

How to handle a polyp in the gallbladder is another topic we must address. Unlike polyps in the colon or stomach, polyps on the gallbladder wall are usually pedunculated or sessile. Radiofrequency is not an adequate thermal coagulator. As described in our previous study, ⁷ we have developed a coaxial bipolar microwave antenna that provides sufficient coagulation on the stalk or base of the polyps without perforation or bleeding. The prevention of mucosal bleeding using nephrine saline (1:1000 dilution) irrigation of the gallbladder lumen resulted in a clear view of the gallbladder cavity; thus, polyp coagulation with a microwave probe and removal with a soft forceps can be safely performed. Our animal study also demonstrated that appropriate settings of the microwave energy induced the mucosa to recover to normal 2 weeks after the operation. This reversible damage to the gallbladder wall ensures that gallbladder functioning is preserved after the procedure. We further believe that thermal injury to the polyp's stalk or basement was able to prevent polyp recurrence in the same location.

Intraoperative endoscopy is a necessary supplement to avoid missing polyps or stones. The flexible choledochoscope is another powerful tool because it can be conveniently adjusted to different angles and can explore any site of the gallbladder inner surface. ¹⁶ Initially, the choledochoscope should be attached to the gallbladder neck where small stones could be located, and then it should be moved gradually to the gallbladder incision where it should be bent as far as possible, until no other gallbladder disease is observed.

Polyp recurrence and the preservation of gallbladder function are the major problems affecting this procedure. However, the absorption and excretory function of the gallbladder should also be further studied. ¹⁷ Although contractions were observed, the correlation between the contractions and Cajal-like cells, a type of dynamic cells that stimulates gallbladder motivation, has not been studied. ¹⁸ The development of a single-incisional laparoscopic technique or robotic surgery would be a revolutionary advancement in the technology for gallbladder preservation.

In conclusion, the Endolap technique we presented here is a safe and feasible procedure. It not only avoids the risk of the complications associated with cholecystectomy but also preserves gallbladder function to the maximum extent possible. However, to the best of our knowledge, currently, the procedure should be limited to benign polyps of the gallbladder. Although no polyp recurrences were detected and gallbladder function was not compromised based on the short follow-up in most cases, the indications for this technique should be determined based on evidence. We suggest that this procedure could be an alternative treatment for patients with benign gallbladder polyps.