Subtotal cholecystectomy is useful for avoiding bile duct injury when a severe inflammation in the neck of the gallbladder limits surgical views . Henneman et al. reported only one bile duct injury in 625 laparoscopic subtotal cholecystectomies , suggesting that subtotal cholecystectomy may be useful as an aspect of reducing the risk of bile duct injury. In contrast, long-term complications associated with remnant gallbladder have been reported [3,4,5,6]. Indeed, Kohga et al.  reported that 1 of 35 patients (3%) who underwent subtotal cholecystectomy developed remnant cholecystitis. Between January 2018 and December 2019, 359 patients underwent LC in our hospital. We performed subtotal cholecystectomy in 9 patients (laparoscopic procedures in 2 patients, and open laparotomies in 7). None of the 9 patients had fallen stones, but one patient (Case 2 [11%]) had remnant cholecystitis. These results suggest that remnant cholecystitis is one of the most crucial complications after subtotal cholecystectomy.
Two methods of subtotal cholecystectomy have been proposed: fenestrating and reconstituting . Fenestrating requires as much removal of the gallbladder wall as possible, leaving the neck of the gallbladder, and extracting any stones. The cystic duct is closed from the inside with a purse-string suture and the lowest part of the gallbladder is left open. Reconstituting also involves removing the gallbladder wall, but leaves behind the lowest part of the gallbladder, and then the stones are removed. The gallbladder wall is then closed with sutures or staples, creating a dead space that could allow for future stone formation. Although fenestrating has been associated with more postoperative bile leakage than reconstituting, most cases of bile leakage are absorbed spontaneously [4, 6]. On the other hand, the incidence of residual stones in the common bile duct was significantly higher in patients who underwent reconstituting compared with patients who underwent LC (16.6% vs 0.7%) . Furthermore, in long term follow-up after subtotal cholecystectomy, reformation of gallstones was observed in up to 5% of cases and these patients usually underwent subtotal reconstituting procedures . Therefore, it is necessary to be vigilant for long-term complications associated with the reconstituting procedure. In case 1 we could not perform a total residual cholecystectomy due to severe adhesions, thus we opted to proceed with reconstituting. Given his history of a mesh repair for a previous ventral incisional hernia, we were concerned that any potential post-operative bile leakage would be a nidus for a mesh-related infection, and this further supported our decision against a fenestrating procedure. Because of the potential risk for cholecystitis recurrence in the remnant gallbladder, the patient will have long-term, close follow-up evaluation.
Further studies are needed to assess the operative indications for fenestration versus reconstitution.
Our two cases suffering remnant cholecystitis underwent reconstituting procedures, and stones were observed in the remnant gallbladder. Kohga et al. measured the remnant gallbladder diameter by MRCP in 35 patients after subtotal cholecystectomy . No long-term complications were observed in 15 patients in whom the remnant gallbladder could not be identified by the image. On the other hand, long-term complications were observed in 8 of 20 patients (median remnant gallbladder diameter, 22.6 mm) in whom the remnant gallbladder was identified on imaging. They reported that there was a significant correlation between the remnant gallbladder diameter and long-term complications. Due to the size of the remnant gallbladder in both our cases, 38 × 36 mm and 47 × 29 mm, respectively, they had a higher risk for long-term complications.
Remnant cholecystitis is thought to be due to the severe adhesions from both prior cholecystitis and current inflammation. Moreover, there may be some anatomical variations caused by the previous surgery. Therefore, the surgical difficulty for remnant cholecystitis is considered high and bridging prior to surgery may be needed to minimize potential complications associated with the high inflammatory state. Percutaneous transhepatic gallbladder drainage (PTGBD) is often performed to improve the inflammation for severe cholecystitis as recommended in TG18. However, PTGBD for remnant cholecystitis is often difficult because the remnant gallbladder consists of the lowest part of the gallbladder and the area of remnant gallbladder contacting with the gallbladder bed is relatively small. EGBD is a useful technique to drain remnant gallbladder without requiring transhepatic puncture [7,8,9]. In fact, although both of our cases had remnant gallbladders greater than 30 mm, it was impossible to perform PTGBD. EGBD improved the persistent cholecystitis, allowing for elective surgery afterwards. EGBD is known as a difficult procedure. In our hospital, we attempted to perform EGBD on 47 patients with cholecystitis (not remnant cholecystitis) from December 2011 to December 2018. Among the 47 patients, 4 patients failed (2 patients had extravasation from the cystic duct; 1 patient had impaction of stones in the cystic duct; and it was not technically possible to cannulate the cystic duct in 1 patient) and EGBD was successful in 43 patients (91.5%). Therefore, outcomes for patients with remnant cholecystitis may be improved if transferred to advanced facilities with not just experienced surgeons, but also endoscopists trained in EGBD tube placement techniques. Moreover, it may be difficult to identify the remnant gallbladder due to severe adhesion or anatomical variation, in which case the EGBD tube could be a landmark to identify the remnant gallbladder intraoperatively.