Pancreatoscopy guided lithotripsy for difficult pancreatic duct stones: Evidence and treatment selection in chronic pancreatitis

Table 1 Phenotype-driven features that define difficult pancreatic duct stones

Domain	High-yield features	Clinical implication	Preferred action/caveat
Stone phenotype	> 5 mm size, impaction, multiple or chain-like burden, radiolucency, high CT attenuation, poor fluoroscopic target	Predicts failure of simple ERCP extraction and informs selection between intraductal and extracorporeal fragmentation	Classify size, density, location, burden, and radiopacity before ERCP; avoid repeated extraction attempts when mechanical failure is predictable
Duct anatomy	MPD diameter, downstream dominant stricture, tortuosity, angulation, side-branch disease, inflammatory head mass	Determines pancreatoscope passage, fragment clearance, drainage durability, and need for stricture therapy	Treat drainage and stricture control as part of the same obstruction syndrome, not secondary details
Access route	Major papilla, minor papilla, pancreas divisum, surgically reconstructed anatomy, EUS-guided access route	May favor conventional ERCP, pancreatoscopy, ESWL, surgery, or expert-center antegrade salvage	Avoid intraductal lithotripsy when safe access and drainage are not achievable
Pain and patient phenotype	Intermittent vs constant pain, opioid use, admissions, malnutrition, diabetes, exocrine insufficiency, central sensitization	Determines probability that ductal clearance will translate into durable clinical benefit	Assess pain and QoL before committing to repeated endotherapy; involve pain, nutrition, and diabetes care early
System factors	ESWL availability, pancreatoscopy expertise, anesthesia, trained assistants, quality monitoring, pancreatic surgery backup	A technically attractive modality may be locally unsafe, unavailable, or inefficient	Use local capability honestly; refer when required expertise or backup is not available

CT: Computed tomography; ERCP: Endoscopic retrograde cholangiopancreatography; MPD: Main pancreatic duct; EUS: Endoscopic ultrasound; ESWL: Extracorporeal shock wave lithotripsy; QoL: Quality of life.