Choledochoscope-Guided Necrosectomy for Retroperitoneal and Posterior Rectal Post-Pancreatitis Necrosis

Introduction

Approximately 20% of patients with acute pancreatitis develop pancreatic necrosis, and secondary infection occurs in about 40–70% of patients with pancreatic necrosis [1]. Infected pancreatic necrosis (IPN) is one of the main causes of death in patients with severe acute pancreatitis. The pancreas is a non-encapsulated organ located retroperitoneally, so necrosis development can spread from the to the retroperitoneal space. The present report presents a unique case of severe acute pancreatitis concomitant with extensive retroperitoneal necrosis extending into the posterior rectum, a combination that has rarely been reported.

Case Report

The patient, a 41-year-old Chinese man, was admitted to our institution with the chief complaint of epigastric pain for 2 days. He had hypertension. His initial vital signs were: temperature 36.5°C, blood pressure 90/50 mmHg, heart rate 140 beats/min, respiratory rate 25 breaths/min. Laboratory test results were as follows: blood amylase 1943 U/L, urinary amylase 9249 U/L, white blood cells (WBC) 24.92×109/L, creatinine 272.7 µmol/L, potassium 5.80 mmol/L, sodium 135.5 mmol/L, pH 7.20, PO2 140 mmHg (FIO2 50%), triglycerides (TG) 11.53 mmol/L, total cholesterol 6.81 mmol/L, total bilirubin 22.38 µmol/L, indirect bilirubin 15.78 µmol/L, direct bilirubin 6.6 µmol/L, alanine aminotransferase (ALT) 60 U/L, aspartate transaminase (AST) 72 U/L, alkaline phosphatase (ALP) 95 U/L, γ-glutamyl transferase (GGT) 83 U/L. Computed tomography (CT) showed features of acute pancreatitis (Figure 1). The diagnosis of acute pancreatitis is clear according to the revised Atlanta classification criteria [2]. De Pretis’s research shows that the diagnosis of hypertriglyceridemic pancreatitis (HTGP) is therefore definitive when serum triglyceride levels are >1000 mg/dL (11.3 mmol/L) at clinical onset [3]. Considering the results of the examination, it was concluded that the patient had pancreatitis due to hyperlipidemia. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 23. The patient was diagnosed with severe acute pancreatitis, hyperlipidemia, shock, and acute kidney injury, so the patient was admitted to the intensive care unit for treatment.

On the first day of admission, the patient’s blood pressure was 90/50. This was considered indicative of shock due to abdominal infection leading to internal environmental fluid loss, so the patient was given empirical intravenous piperacillin-tazobactam and bolus injections of intravenous fluid were administered. Norepinephrine was infused to maintain hemodynamic stability. On the second day of admission, he developed acute respiratory distress syndrome and renal failure. Therefore, endotracheal intubation was performed the same day for ventilation management and the patient was given continuous renal replacement therapy. On the fifth day of admission, the patient’s intra-abdominal pressure rose to 17 cm-H2O by bladder pressure measurement and was diagnosed as intra-abdominal hypertension (IAH). A left retroperitoneal and peripancreatic effusion was seen under ultrasound, so the patient was treated with ultrasound-guided puncture and catheter drainage. The puncture aspirate contained reddish-brown pus, so the drainage fluid was immediately sent for culture. On the sixth day of admission, abdominal CT showed necrosis formation from the left retroperitoneal space to the posterior rectum (Figures 2, 3). Studies have shown that early puncture and catheter drainage in patients suffering from severe acute pancreatitis can be highly beneficial [4]. This procedure helps in effectively removing pancreatic necrotic tissue and infectious pus, positively impacting the control of abdominal infection, reducing the risk of multiple organ failure, and managing the progression of severe acute pancreatitis. Therefore, the patient was treated with ultrasound and CT-guided puncture and catheter drainage, and this procedure was repeated many times. There was pus in the puncture aspirates, so the drainage fluid was immediately sent for culture. This was also done repeatedly several times. On the tenth day of admission, the patient’s renal function and respiratory function recovered. The endotracheal tube was removed and renal replacement therapy was discontinued, and the patient’s intra-abdominal pressure dropped to 7 cmH2O. The patient was transferred to the general ward for further treatment. On the 13th day of admission, slow enteral nutrition was started, via transnasal jejunal feeding.

On the 36th day of admission, the patient’s abdominal CT showed the bubble sign, indicating infectious pancreatic necrosis (Figure 4). The patient then experienced continuous fever during intravenous antibiotic infusion with tigecycline and imipenem. Drainage fluid culture tests detected Citrobacter freudii, Candida tropicalis, and Escherichia coli. Laboratory test results showed WBC from 24.92×109/L to 14.38×109/L, C reactive protein (CRP) from 389.00 mg/L to 124.78 mg/L, albumin from 34 g/L to 27.2 g/L (under intravenous and enteral nutritional supplementation). The patient showed intolerance to attempts to give adequate amounts of enteral nutrition and the residual focus of infection elicited a systemic inflammatory response, resulting in a catabolic state, increasing caloric and nutritional requirements [5], so the patient was in a state of negative nitrogen balance. At this point, the necrosis was considered mature, and drainage via percutaneous catheter was not effective enough. Therefore, a surgical intervention was planned. On the 41st day of admission, the patient was drained by a CT guided percutaneous puncture, and 2 drainage catheters were placed in the peripancreatic area through the left and right retroperitoneal regions. The percutaneous drains were in place for the surgery.

On the 45th day of admission, choledochoscope-assisted pancreatic necrosectomy was performed. The incisions were made adjacent to the percutaneous drain through the retroperitoneal region. Then, the incisions were advanced into the retroperitoneum by following the course of the catheter with the catheter in place. After flushing and exploration through the choledochoscope, a ringed forceps was inserted through the incision and used to gently debride the solid necrotic tissue in the safety zone around the pancreas (eg, necrotic tissue in the periphery; necrotic tissue away from blood vessels). For necrotic tissue in dangerous areas, delicate manipulation was required to remove the necrotic tissue with a stone retrieval basket under direct choledochoscopic vision. After pancreatic necrosectomy, 8 triple-lumen sump drains were placed. After the operation, the patient was given continuous saline flushing through the drain and low continuous suction was applied to the lumen sump drain. In the following 30 days, the choledochoscope-assisted pancreatic necrosectomy needed to be conducted 2 times. After 3 surgeries, the patient’s white blood cells returned to normal and his CRP decreased from 124.78 mg/L to 57.96 mg/L. However, the patient still had intermittent fever after these operations. During the fourth choledochoscope-assisted pancreatic necrosectomy, since it was possible to advance the catheter into the pelvic cavity, we decided to use an M10 triple lumen sump drain. The ringed forceps was inserted through the sheath of the M10 triple lumen sump drain and used to gently debride the solid necrotic tissue around the posterior rectum. Then, a triple lumen sump drain was placed in the posterior rectum (Figure 5). After the operation, the patient was given continuous saline flushing through the lumen sump drain. CRP then decreased from 57.96 mg/L to 18.43 mg/L. From the time of admission to the time of publication of this case report, the patient underwent 20 surgeries. The surgeries positively impacted the control of abdominal infection, and served to manage the progression of severe acute pancreatitis (Figure 6A, 6B). An outline of the treatment process is shown in Figure 7. During these 20 surgeries, the number of the patient’s abdominal drains gradually decreased, and the diameter of the drains gradually became thinner as the necrotic tissues in the abdominal cavity were gradually removed (Figures 8, 9). On the 142nd day of admission, the patient remained fever free after stopping the antibiotics, and albumin increased from 27.2 g/L to 42 g/L. Seven months after the onset of the disease, the patient’s condition stabilized and the patient recovered well. Then, the patient was discharged from the hospital and returned to the hospital every 2–3 weeks thereafter.

Discussion

The most common locations of extrapancreatic inflammation are the lesser sac, posterior pararenal space, and paracolic gutter, with the pelvis being the least common [6]. In the case described in the present report, the patient developed extensive retroperitoneal necrosis extending into the posterior rectum following severe acute pancreatitis. The value of necrosectomy has been widely reported in recent years, including laparoscopic-assisted pancreatic necrosectomy (LAPN) [7] and endoscopic necrosectomy [8]. In the present manuscript, we report our institution’s method for choledochoscope-assisted pancreatic necrosectomy and provide the results of our experience.

The timing for operative intervention depends both on whether the necrosis is mature, and whether drainage via percutaneous catheter was effective enough, while receiving broad spectrum antibiotics. In the present case, the infection focus in the posterior rectum was a secondary infection site, while the primary infection focus was peripancreatic necrosis. Therefore, the first 3 surgeries mainly dealt with the pancreatic and peripancreatic infection. However, the patient’s fever persisted after 3 surgeries. To control retroperitoneal infection, the fourth choledochoscope-assisted pancreatic necrosectomy was performed on the 80th day of admission. As much necrotic tissue around the posterior rectum as possible was removed. Then, a triple lumen sump drain was placed in the posterior rectum. As of the publication of this case report, the patient was still scheduled to return to the hospital for surgery. The number of abdominal drains gradually decreased and the diameter of the drains gradually became thinner as the necrotic tissues in the abdominal cavity were gradually removed. According to our center’s clinical experience, residual infections can worsen and patients may even experience abdominal pain and fever again after stopping the surgery too early. The need for surgery requires a comprehensive assessment by the operator based on the last intraoperative situation and the nature of the patient’s flushing fluid. If pus is still visible intraoperatively, and the postoperative washout is turbid, continued surgery to clear the pus is required. When no more neoplastic granulation tissue was visible during the operation and the rinsing fluid was clear, then the operation was able to be stopped, and the drainage tube was gradually removed. Makoto Morita et al reported the successful treatment of a case of walled off necrosis extending into the pelvis by endoscopic necrosectomy [9]. It is difficult for a double-pigtail plastic biliary stent to drain the sub-cavity that exists in a location far from the digestive tract. Therefore, a double-pigtail plastic ureteral stent was used to approach the sub-cavity of the pelvic cavity. In this manuscript, we report our institution’s method for removing necrotic tissue around the posterior rectal area. We decided to perform choledochoscope-assisted pancreatic necrosectomy. The necrotic tissue around the posterior rectal area was removed and a triple lumen sump drain was placed in the posterior rectal area. After the operation, the patient was given continuous saline flushing through the lumen sump drain. This report may offer some advantages in that it describes the removal of the necrotic tissue around the posterior rectal area and the flush of the lumen sump drain.

Conclusions

This is the first case of infection of the posterior rectal space after severe acute pancreatitis treated by choledochoscope-assisted pancreatic necrosectomy. It may offer some advantages in that it describes the removal of necrotic tissue around the posterior rectal area, and flushing of the lumen sump drain.