INTRODUCTION
Chronic pancreatitis is characterized by chronic progressive inflammation, destruction and scarring of the pancreatic tissue, all of which can lead to permanent loss of pancreatic function in both the exocrine and endocrine glands of the organ. As a condition with appreciable prevalence and incidence worldwide, accumulated research efforts have provided substantive insights into its etiology, pathophysiological course, and clinical manifestations[1]. The resultant advancements in radiologic and endoscopic techniques for examining this condition have increased the rate of diagnosis and helped to identify cases eligible for treatment in a more timely manner.
The most common clinical signs of chronic pancreatitis are deficiencies in pancreatic exocrine and endocrine enzymes (known as pancreatic insufficiency) and chronic abdominal pain. The pancreatic-type pain manifests from major pancreatic duct obstruction consequent to ductal stone blockade, peri-pancreatic ductal fibrosis, or parenchymal calcification. A multitude of therapeutic approaches are available for treatment of main pancreatic duct (MPD) obstruction in chronic pancreatitis, and range from pharmacologic, endoscopic and radiologic approaches to surgical intervention[2-4]. These approaches are also applied to resolve obstructions of the MPD associated with post-operative anastomotic stricture resulting from the Whipple procedure or surgeries to address disconnected pancreatic tail syndrome or necrotizing pancreatitis with complete duct rupture[5]. Until resolution, the obstruction of drainage of pancreatic juices causes ductal hypertension which manifests as pancreatic-type pain[6,7].
The pharmacologic treatments, such as pancreatic enzyme supplementation and analgesics, can relieve the pain symptom but do not resolve the obstruction-induced ductal hypertension[4,8]. Resolutive treatments, on the other hand, include physical interventions, using surgical or the less-invasive endoscopic approaches. Endoscopic retrograde pancreatography (ERP) with pancreatic duct drainage is the current preferred first line treatment[5-9], and reportedly leads to complete or partial relief of the pain symptom in up to 80% of cases[9,10]; however, the ERP intervention reportedly fails to achieve pancreatic duct drainage in 5%-10% of cases, even when performed by experienced endoscopists[11,12]. The reported reasons for failure of pancreatic drainage are various and include chronic inflammation-related changes in the tissues of the periampullary region, complete MPD obstruction, post-surgical anastomotic changes, tortuous configuration of MPD, and obstructions of the gastric outlet and duodenum[11,13-15]. Surgery remains the most effective intervention for chronic pancreatitis since it can resolve ductal hypertension while facilitating resection of pathologic foci; in addition, the surgical approach allows for localized disease treatment in the absence of ductal dilatation[11]. When MPD dilatation is present, however, the surgical drainage is most frequently achieved by longitudinal pancreaticojejunostomy; although, this procedure carries high rates of complications (reportedly up to 30%) and mortality (reportedly up to 2%)[4,16-20].
For patients with contraindications for surgery or who decline the surgical treatment, endoscopic intervention is considered. ERP with pancreatic duct drainage is the least invasive of the available endoscopic treatments and is often offered as the first line treatment for this alterative therapeutic approach[21-23]. However, if pancreatic duct cannulation by the standard ERP approach fails, alternative endoscopic techniques are available; these techniques include the endoscopic ultrasound (EUS)-guided rendezvous technique using a transpapillary approach or antegrade stenting and the EUS-guided transmural drainage technique[24].
Here, we report the successful application of EUS-guided pancreaticogastrostomy (EUS-PGS) using a fully covered, self-expandable metallic stent (SEMS) to resolve a case a chronic pancreatitis.
CASE REPORT
A 42-year-old man presented to our clinic with complaint of post-prandial chronic epigastric pain that had lasted for 3 mo. At intake, the patient reported no pre-existing illness but revealed a 14-year history of heavy alcohol intake. The patient described the abdominal pain as very severe and radiating into his back. Other reported symptoms included anorexia, nausea and vomiting, with unintentional weight loss of a few kilogram. Physical examination revealed mild epigastric tenderness without rebound tenderness or abdominal mass. Blood workup showed complete blood count in the normal range, high fasting glucose (115 mg/dL; reference range: 74-99 mg/dL), normal total/direct bilirubin (0.6/0.2 mg/dL; reference range: 0.0-1.2 mg/dL), normal serum glutamic oxaloacetic transaminase/serum glutamic pyruvic transaminase (SGOT/SGPT) (21/15 U/L; reference range: 0-41 U/L), normal alkaline phosphatase (75 U/L; reference range: 40-130 U/L), low amylase (25 U/L; reference range: 28-100 U/L), and low lipase (12 U/L; reference range: 13-60 U/L). Coagulation tests were normal.
The patient underwent esophagogastroduodenostomy, which showed unremarkable findings. Radiologic examinations of the upper abdomen by computed tomography and magnetic resonance imaging demonstrated atrophic pancreatic parenchyma with heavy calcification; in addition, the pancreatic duct showed a beaded appearance and dilation, with duct size measuring 7 mm at the maximal diameter. Accumulation of pancreatic juices was detected in the MPD adjacent to the pancreatic head, and multifocal narrowing and focal wall thickening was detected in the cystic duct and extrahepatic common bile duct. The collective radiologic findings strongly suggested a diagnosis of chronic pancreatitis (Figure 1).
Figure 1 Radiologic imaging finding showing an atrophic pancreatic parenchyma dilatation of pancreatic duct to 7 mm in diameter.
A: Magnetic resonance image; B: Magnetic resonance cholangiopancreatography.
Pharmacological treatment was initiated and consisted of pancreatic enzyme supplements, tricyclic anti-depressant, and analgesic agents. When the nearly 1-year treatment produced no improvement in symptoms, including of the abdominal pain, the patient was referred for endoscopic pancreatic duct decompression. Initially, ERP with transpapillary drainage was attempted but the procedure could not be completed due to tight stricture of the pancreatic duct at the pancreatic genu that hindered passage of the guidewire.
The patient developed post-ERP pancreatitis and at day 3 post-ERP was offered the alternative treatment options of EUS-guided pancreatic duct drainage (rendezvous or PGS) as well as surgery. The patient and his family were informed of all procedure-related risks, benefits and long-term outcomes. At this time, the patient was discharged for decision-making and he returned 14 d later to undergo the selected EUS-guided intervention. Upon admission for the procedure, the patient provided informed consent for the procedure and publication of any and all data related to his case. For the treatment, the patient was positioned on the left lateral decubitus in the supine position and was put under intravenous sedation using propofol.
A curvilinear echoscope (GF-UCT 140-AL5; Olympus, Tokyo, Japan) was used for scanning. The endoview was unremarkable, and the echoview demonstrated non-homogeneous pancreatic parenchyma with hyperechoic foci and strands, lobulation, and parenchymal calcifications. The MPD, from the body to tail, was irregular, tortuous, and dilated up to 7 mm (Figure 2). An optimal puncture site was located to access the full MPD, from the body to tail, and a 19-gauge needle (Expect™ Slimline; Boston Scientific Corp., Spencer, IN, United States) was inserted. The aspirated liquid was clear. Contrast media was injected for the pancreatography, and the MPD was observed to be tortuous and dilated to between 6 mm and 8 mm in diameter (Figure 3). A 0.025 stiff guidewire (VisiGlide™; Terumo Medical Corp., Somerset, NJ, United States) was negotiated proximally, but passage down through the papilla was not possible (Figure 4). Therefore, the endoscopist decided to perform PGS. The neo-tract was created using a needle knife (MicroKnife™; Boston Scientific Corp., El Coyol, Alajuela, Costa Rica), followed by dilation using a 5 Fr Soehendra biliary dilation tapered tip catheter (Wilson-Cook Medical, Inc., Winston-Salem, NC, United States), a 7 Fr Soehendra dilation catheter, a Soehendra stent retriever size 8.5 Fr, and an 8.5 Fr Soehendra dilator (Figure 5). Then, a 10 mm × 60 mm fully covered metallic stent (Niti-S Biliary Covered Stent™; TaeWoong Medical Co, Ltd., Gimpo-si, Gyeonggi-do, Korea) was inserted and deployed between the MPD and gastric cavity; good position and satisfactory drainage was achieved (Figure 6). After 5 d of uneventful in-hospital recovery, the patient was discharged.
Figure 2 Echoview of the main pancreatic duct, from the body to tail, showing irregular and tortuous configuration and dilation up to 7 mm.
Figure 3 Pancreatography showing the main pancreatic duct to be irregular, tortuous, and dilated.
Figure 4 Fluoroscopic view showing the guidewire at the point it was hindered from passing through the papilla.
Figure 5 Fluoroscopic views during the neo-tract dilation.
Figure 6 Fluoroscopic views after stent deployment.
At the 6-mo follow-up appointment, the patient reported no recurrence of abdominal pain and weight gain of 3 kg. The blood workup showed results within normal range for complete blood count and for all liver function markers. The patient continued taking the pancreatic enzyme supplement, but analgesics and anti-depressants were deemed unnecessary and discontinued. At the last follow-up (attended at 6 mo), the patient was healthy and had gained an additional 3 kg. The blood workup again showed results within the normal ranges, including those for lipase, amylase, and CA19-9. Pancreatic stent removal was planned for 6 mo to 9 mo following this appointment.
DISCUSSION
When conventional endoscopic techniques for pancreatic drainage fail, two alternative endoscopic approaches may be considered. The first technique is the rendezvous technique followed by transpapillary approach, and is recommended by some expert endoscopists as the first line option due to its general safety and efficacy[24-27]. For the case described herein, we attempted to perform this technique initially but the attempt failed when the guidewire could not be negotiated down through the stricture point, possibly due to the patient’s complete MPD obstruction at the pancreatic genu. The second technique is the EUS-PGS. Since its first description in the literature in 1995 by Harada et al[28] several case series successfully treated by this technique have been reported, but with the majority having used plastic stents[24,26,29-34]. However, the safety profile of plastic stents is negatively impacted by their potential to migrate from the intrapancreatic location[35], the not infrequent failure rate of achieving stent placement, and the association with pancreatic fluid leakage following placement[36,37].
Recent case reports have demonstrated the advantages of using fully covered SEMS, which include longer stent patency, applicability to larger sized pancreaticogastric fistula, reduced rates of re-intervention, and increased ease of re-intervention to resolve cases of stent obstruction[38,39]. Moon et al[40] reported a case series of 25 patients with painful obstructive pancreatitis, including 10 cases of chronic pancreatitis, all of who failed the initial ERP treatment and then underwent EUS-guided pancreatic drainage using fully covered SEMS. The study showed a 100% technical success rate and 100% clinical success rate, without any occurrences of stent-related adverse events (mean follow-up: 221.1 d).
The stents used in the study by Moon et al[40] were either 6 mm or 8 mm in diameter, which are not readily available in the global medical device market. For example, our hospital did not have ready access to stents of those sizes and only a regular-sized biliary stent, of 10-mm, was available. Therefore, we performed the EUS-PGS using the 10-mm biliary stent and drainage was achieved without occurrence of any stent-related adverse event during the 6-mo follow-up period.
In conclusion, we have shown that a regular biliary fully covered SEMS can be used effectively and safely for EUS-PGS.
COMMENTS
Case characteristics
A 42-year-old man presented with severe abdominal pain that had lasted for 3 mo. Computed tomography scanning showed evidence of chronic obstructive pancreatitis with pancreatic duct stricture at genu. After conventional endoscopic retrograde pancreaticography failed to eliminate the symptoms, endoscopic ultrasound (EUS)-guided pancreaticogastrostomy (PGS) was applied using a fully covered, self-expandable, 10-mm diameter metallic stent.
Clinical diagnosis
Chronic pancreatitis with pancreatic duct stricture.
Differential diagnosis
Pancreatic duct stone.
Laboratory diagnosis
Increased blood glucose (115 mg/dL; reference range: 74-99 mg/dL); Liver chemistry results: normal total/direct bilirubin (0.6/0.2 mg/dL; reference range: 0.0-1.2 mg/dL), normal serum glutamic oxaloacetic transaminase/serum glutamic pyruvic transaminase (21/15 U/L; reference range: 0-41 U/L), normal alkaline phosphatase (75 U/L; reference range: 40-130 U/L), low amylase (25 U/L; reference range: 28-100 U/L), low lipase (12 U/L; reference range: 13-60 U/L).
Imaging diagnosis
Magnetic resonance imaging showed trophic pancreatic parenchyma with heavy calcification and the pancreatic duct with a beaded appearance and dilatation of 7 mm at the maximal diameter; in addition, multifocal narrowing and focal wall thickening was observed in the cystic duct and extrahepatic cystic bile duct.
Treatment
EUS-guided PGS using a 10-mm, fully covered self-expandable metallic stent (FCSEMS).
Term explanation
EUS is a novel endoscopic intervention applied through the gastrointestinal tract for diagnostic evaluation and therapeutic interventions. EUS-guided PGS is a therapeutic intervention used to create a new connection between the main pancreatic duct and stomach to achieve pancreatic drainage.
Experiences and lessons
A 10-mm FCSEMS represents a feasible and safe tool for achieving drainage of the pancreatic duct via the EUS-guided PGS procedure.
Peer-review
This is an interesting case report aimed at describing and explaining the treatment of pancreatic duct obstruction by EUS-guided PGS using a fully covered metallic stent that is 10 mm in diameter.
