Stonebreakers: the era of pancreatic stones treatment

Keywords::

• chronic pancreatitis
• endoscopic retrograde cholangiopancreatography
• pancreatic extracorporeal shock wave lithotripsy
• pancreatic stones
• surgery

“Porter: Faith sir, we were carousing till the second cock; and drink, sir, is a great provoker of three things.

MacDuff: What three things does drink especially provoke?

“Chronic calcifying pancreatitis is related to alcohol abuse and smoking, but can also be related to genetic causes or be idiopathic.”

Porter: Marry, sir, nose-painting, sleep, and urine. Lechery, sir, it provokes, and unprovokes; it provokes the desire, but it takes away the performance.”William Shakespeare (Macbeth: Act 2, Scene 3)

Pancreatic stones were first reported by Graaf in 1667. More than 200 years later, in 1896, Pierce Gould was probably the first one who surgically removed pancreatic stones. We waited for another 100 years to see pancreatic extracorporeal shock wave lithotripsy (P-ESWL) and endoscopy as mini-invasive techniques for the removal of pancreatic stones [1,2].

Chronic calcifying pancreatitis (CCP) is related to alcohol abuse and smoking, but can also be related to genetic causes or be idiopathic [3,4]. Pancreatic stones are composed of carbon salts, phosphorus or magnesium salts and organic matter [5], which is practically the same composition of marble. The pathogenesis of stones formation is complex and includes a series of biochemical processes [4].

Pain is the most distressing symptom in patients with chronic pancreatitis. Removal of occluding pancreatic stones decreases the pressure of the duct which results in reduction or disappearance of pain.

Pain is probably the only indication for treatment. In fact, asymptomatic pancreatic stones, even if occluding the main pancreatic duct and with dilation above, can be left untreated.

In the past two and a half decades, the experience in treatment of symptomatic pancreatic stones has rapidly grown.

P-ESWL and endoscopic retrograde cholangiopancreatography (ERCP) are accepted worldwide as alternatives to surgery in patients with CCP. As reported, less than 20% of these patients require a surgical approach [6–11]. However, in a long-term follow-up study performed on 39 patients randomized to surgery or endoscopy, Cahen et al. found increased efficacy of surgery when compared with P-ESWL and ERCP [12]. Nevertheless, Seven et al., in a recent retrospective study evaluating 120 patients with CCP, treated with P-ESWL and ERCP [11], reported partial and complete pain relief in 85 and 50% of patients, respectively, avoiding surgery in 84% of patients.

Pancreatic stones may, in some circumstances, act as predictors of outcome: for instance, the presence of pancreatic head calculi in patients with chronic pancreatitis-related common bile duct stricture has been found to be associated with poor results of endoscopic biliary stenting [13,14]. In these cases, hepaticojejunostomy is the most reasonable treatment [15].

Lithotripsy alone in patients with a single pancreatic stone, located in the pancreatic head, may be effective as a single treatment [8].

Fragmentation of pancreatic stones can also be done by intraductal electrohydraulic lithotripsy. However, at present, there are scarce data on this technique [16]. Electrohydraulic lithotripsy requires direct vision with a pancreatoscope mother–baby scope system. The advantage of this system is the possibility to deliver high energy to a tightly focused area of the stone, but duct injury including perforation can also occur.

As mentioned, at present, P-ESWL and ERCP are treatments of choice in painful CCP. However, in the literature, there are a lot of discrepancies on how to treat these patients, and as a consequence, there are also different data in the outcomes. In particular, it is not clear if the treatment of pancreatic stones should start with ESWL or with ERCP. For instance, some authors prefer to perform ERCP 24–72 h after P-ESWL, while others perform ERCP immediately before or immediately after ESWL [11,17,18]. There are also scarce data regarding the quantity of waves and force that should be administered per P-ESWL session, and the time of each procedure (this naturally depends on the ESWL equipment). Furthermore, the treatment of radiolucent pancreatic stones or on the other hand very hard pancreatic calculi, poorly responsive to P-ESWL, is almost completely personalized and depends on the local expertise.

Also in our institute, we have our ‘personalized’ treatment of pancreatic stones. We almost always perform P-ESWL before ERCP (Siemens LITHOSKOP^®); P-ESWL is carried out in multiple sessions (medially 5000 waves/session, force 3–8, head pressure 1–5) until there are signs of stone fragmentation similar to a ‘popcorn effect’ (explosion of the stone), ‘comet effect’ (filling of the pancreatic duct with stone fragments) or complete clearance of the stone. In the case of incomplete fragmentation and nonextractable stones at ERCP, we usually place a naso-pancreatic drain in order to slowly and gently flush the pancreatic duct with saline. In these cases, P-ESWL is repeated while flushing the duct. This allows a fluid film to be created around the stone in order to improve the effect of the shock waves. In our experience, this approach is highly effective. In some cases of nonextractable stones, we insert a pancreatic stent, in case of further P-ESWLs.

In the discussion of their recent study, Seven et al. mentioned the problem of discrepancies in the different ways of treating of CCP and different clinical outcomes reported in published studies [11].

In the literature, there are a number of studies on the treatment of painful CCP by P-ESWL alone or combined with ERCP, but only few studies are prospective, follow-up is often on short term, and generally these studies are nonrandomized [6–11,19,20]. What we have learned from these studies is that P-ESWL is a safe and effective treatment modality for CCP, generally there is a good improvement in pain, quality of life and narcotic pain medication use. Interesting data that emerged from the study of Seven et al. is that narcotic pain medication use was significantly reduced among patients who were smokers before P-ESWL, and stopped smoking after P-ESWL [11], however, we do not know if the same applies for alcohol users.

It is a fact that retrospective studies are an important way to define current therapy, but what we need at the moment is a large multicenter prospective study, randomized to surgery, based on precise guidelines for the treatment of patients with symptomatic CCP. The creation of guidelines for the treatment of patients with CCP will probably help to best treat these patients.

The future will probably bring more sophisticated and mini-invasive ways for the treatment of pain in CCP. Until then, it seems that the most reasonable treatment for future generations is prevention, in terms of alcohol abuse and smoking. Even Shakespeare would have suggested it!

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.