Lost gallstones during laparoscopic cholecystectomy as a common but underestimated complication—case report and review of the literature

Introduction Laparoscopic cholecystectomy (LC) represents one of the most commonly performed routine abdominal surgeries. Nevertheless, besides bile duct injury, problems caused by lost gallstones represent a heavily underestimated and underreported possible late complication after LC. Methods Case report of a Clavien-Dindo IVb complication after supposedly straightforward LC and review of all published case reports on complications from lost gallstones from 2000-2022. Case Report An 86-year-old patient developed a perihepatic abscess due to lost gallstones 6 months after LC. The patient had to undergo open surgery to successfully drain the abscess. Reactive pleural effusion needed additional drainage. Postoperative ICU stay was 13 days. The patient was finally discharged after 33 days on a geriatric remobilization ward and died 12 months later due to acute cardiac decompensation. Conclusion Intraabdominal abscess formation due to spilled gallstones may present years after LC as a late complication. Surgical management in order to completely evacuate the abscess and remove all spilled gallstones may be required, which could be associated with high morbidity and mortality, especially in elderly patients. Regarding the overt underreporting of gallstone spillage in case of postoperative gallstone-related complications, focus need be put on precise reporting of even apparently innocuous complications during LC.


Introduction
Gallstone disease affects up to 20% of the European population.Laparoscopic cholecystectomy (LC) is indicated in patients with symptomatic gallstones, acute cholecystitis or biliary sludge and represents one of the most commonly performed abdominal surgeries (1).
Perforation of the gallbladder is relatively common in LC and is reported in various studies to range between 10% to 40% of procedures.Gallstone spillage is less common, and the true frequency of unremoved stones is difficult to determine.Some case series indicate a range of 6% to 30% (2).Incidence increases if the surgery is performed for acute cholecystitis.Other risk factors include male sex, higher age, obesity and the presence of postoperative adhesions.Complications resulting from these spilled stones are reported to occur in 0.08% to 0.3% of patients, and most of these lost stones remain clinically silent (2).
However, even if dropped gallstones do not cause actual postoperative harm through complications, they often are not correctly identified by imaging and can be mistaken for peritoneal lesions leading to unnecessary concern.Nevertheless, a small percentage of dropped gallstones cause actual complications of immediate or delayed (even months after surgery) clinical concern, such as abscesses and fistulas (3).
Some reports show that only half of the surgeons inform the patient when gallstones are lost during operation, less than 30% inform the general practitioner about this complication and less than a quarter of surgeons informed about this complication in the consent form handed to the patient preoperatively (4).Another part of the problem is the differentiation between intraoperative iatrogenic gallbladder perforation, spillage of gallstones, retrieved and lost gallstones.Underreporting of intraoperative gallbladder perforation is common and it is almost impossible to determine the exact number of spilled gallstones.Despite examination and rinsing, it may be impossible to assure, that all gallstones spilled into the abdomen are really retrieved.
We report a case of an elderly patient presenting with a symptomatic perihepatic abscess 6 months after LC.

Case report
An 86-year-old male patient presented in our surgical ward 6 months after presumed, uncomplicated laparoscopic cholecystectomy performed in May 2022 due to necrotizing cholecystitis with 15 kg of weight loss, anorexia and rapid feeling of fullness since the operation.The patient denied pain or fever.Upon physical examination, the patient reported diffuse abdominal discomfort.The abdomen was described as soft with mild tenderness in the right upper abdomen.Blood tests revealed elevated C-reactive protein and white blood count.His past medical history was significant for severe tricuspid valve insufficiency, atrial fibrillation, type 2 diabetes mellitus and arterial hypertension.
Computed tomography scan (CT, Figure 1) revealed a perihepatic abscess (5.5 × 5.8 cm) with suspected connection to the pleural space and small calcareous structures.Diagnostic laparoscopy was performed.Due to a soft, vulnerable liver, small liver injuries and bleeding, open surgery was necessary to successfully and safely drain the abscess.Upon evacuation, lost gallstones were discovered and removed.Further, the diaphragm was eroded by the chronic inflammation, but the parietal pleura was intact.Follow-up x-rays revealed an increasing pleural effusion, which was considered reactive.Therefore, the placement of a chest tube in the 5th intercostal space at the midaxillary line was additionally needed and was left for 4 days.Empirical intravenous antibiotic therapy with piperacillin + tazobactam 4,000 mg/500 mg twice a day for 3 days was initiated and then switched to meropenem as a single 1,000 mg dose once every 24 h due to increasing C-reactive protein.Antibiotics were deescalated to cefuroxime 750 mg once a day after 4 days according to the antibiogram of the detected Escherichia coli isolated from the intraoperative swab.This antibiotic regimen was followed for another 6 days.
Postoperative ICU stay was 13 days.Reintubation was necessary due to cardiac decompensation with pulmonary edema.In addition, acute to chronic kidney failure developed with need for hemodiafiltration.Cardiac recompensation was achieved using Levosimendan and Landiolol.
The patient was finally discharged after additional 33 days on a geriatric remobilization ward, where his autonomous ability and everyday skills were restored.However, chronic kidney failure with need for hemodialysis persisted.The patient died 12 months after being discharged due to acute cardiac decompensation.
We aimed to conduct a census of all cases with complications from lost gallstones after laparoscopic cholecystectomy from 2000 to 2022 reported in the literature.The results should clarify that late complications from spilled gallstones are rare (0.08% to 0.3% of patients) but can cause severe problems that occur at a median of 36 months after the initial operation.However, it should be taken into consideration, that the published literature mainly covers incidental findings and small case series.
Of note, only 32% of reported cases initially had acute cholecystitis, while in the majority of cases, primary LC had been reported as elective procedure for symptomatic gallstone disease.Concerning a concept of a culture of safe cholecystectomy, surgeons should be facile with the following aspects: Knowledge of relevant anatomy, various anatomical landmarks, and anatomical variations; correct gallbladder retraction; safe use of energy devices; knowledge of the critical view of safety (including its documentation); awareness of various bailout procedures (e.g., cholecystectomy by the fundus-first approach) in difficult gallbladder cases; use of intraoperative imaging techniques (e.g., intraoperative cholangiogram) at uncertain anatomy; respecting the concept of time-out and thorough documentation (93).
It is also alarming that iatrogenic peroration of the gallbladder was only described in 30% of cases causing postoperative complications, suggesting a much higher number of actual gallbladder perforations during LC.Literature on incidental gallstone spillage may be biased by distinct underreporting, considering that only a minority of surgeons document gallbladder perforation and gallstone spillage.Mullerat et al. reported that only half of the surgeons informed their patients and less than 30% informed the general practitioner if gallstones were lost during surgery.The supposed low importance of these complications is underlined by the fact that only a quarter of the surgeons mention this complication in the surgical explanation (4).Operative difficulty is classified according to Nassar Grade and was found to be a significant independent predictor of 30-day complications and 30-day reinterventions.The score could be used to unify the severity of the disease and the technical difficulty of the operation and can be implemented as a tool to document operative findings.Therefore, it can be used in future research to compare outcome and intraoperative difficulties (94).
Since almost 60% of all complications are abscesses, predominant symptoms are fever, pain, abdominal swelling, weight loss, nausea or vomiting.This should lead to radiological cross-sectional imaging in acute diagnostics, which should quickly lead to the correct diagnosis.
The formation of an abscess can be life-threatening.The percutaneous placement of a drain or catheter under imaging control is an increasingly used medical procedure.It is an effective and safe alternative to surgery, reducing discomfort and hospitalization.An amazing 66.6% of the cases required an open procedure and only 12.7% of the patients could be treated with percutaneous drainage (95).Apparently retained gallstones are a problem for percutaneous techniques, because the removal of stones is complex or even impossible.Variations in the location of retained stones, clinical symptoms and individual risk factors of patients demand a personal treatment strategy.However, minimal invasive techniques should be applied, whenever appropriate.Thus, it remains questionable whether a standardized procedure can be found for this complication.In particular, confusion with peritoneal masses can have severe consequences.Complex symptoms such as gastrointestinal reflux, urinary tract infections or breathing problems may lead to a diagnostic dilemma.A collection of case reports has several limitations.As Gavriilidis et al. described, institutional, national, underpowered sample size, learning curve, performance and follow-up bias may have influenced the results.In addition, case reports with a poor outcome, unusual history of the disease and rare complications are more commonly reported in the literature, than those with an uncomplicated course (96).
One way to prevent these biases could be the implementation of international databases that record all complications of laparoscopic cholecystectomy postoperatively and in the follow-up.Therefore, awareness of this complication must be created.Futhermore, there is still a lack of a standardized procedure at the international level for laparoscopic operations for gallbladder diseases.Therefore, the Global Evaluation of Cholecystectomy Knowledge and Outcomes (GECKO) study (GlobalSurg 4) will be an international collaborative initiative that will allow contemporaneous data collection on the quality of cholecystectomies.GECKO is a prospective, international, multicentre cohort study observing patients undergoing cholecystectomy, between 31st July 2023 to 19th November 2023, with follow-up at 30-day and one-year postoperatively.The aim of this study is to define the global variation in compliance to pre-, intra-, and post-operative audit standards including: Interventional radiology service; risk stratification via Tokyo Guidelines 18; timing of surgery; achieving a critical view of safety; intraoperative imaging; initiating different bailout procedures; antibiotic use; use of drains; bile duct injury; 30-day readmission; and critical care (97).

Conclusion
This case report and review of the literature shall emphasize the alertness on exact reporting of complications to patients and attending doctors by exact documentation in operating reports, to think of that late complication after LC when the symptoms described above are present, and is simply intended to create general awareness, since many surgeons are probably not aware of the problem.Radiologists may suspect unclear radiopaque concretions in the CT scan as lost gallstones after LC in order to identify the abscess genesis earlier.It should be avoided that lost stones will not be considered in patients with above presented symptoms, as there is not a single note in the operation report about them being spilled.
Surgical management in order to completely evacuate the abscess and remove all spilled gallstones should be the attempted.Generally, laparoscopic approaches must be preferred for accessible abscess collection.However, percutaneous drainage could be considered as bridge to surgery or for patients unfit for surgery.Nevertheless, attempting to treat intra-abdominal abscesses containing spilled gallstones with percutaneous drainage will always bear the risk of incomplete treatment by leaving stones in the abdomen.If gallstones spill intraoperatively during laparoscopic cholecystectomy, all stones should be recovered and copious peritoneal lavage should be performed.The initial administration of antibiotics seems to be of secondary importance, as it seems most important to eliminate the mechanical trigger.
To sum up, most lost gallstones remain clinically silent, but they may cause complications that can become symptomatic after years from surgery.In patients with unexplained abdominal abscess or fistula with a history of cholecystectomy within the last 10 years, lost gallstones should always be considered.

TABLE 1
Study characteristics of all articles included.