Biliary sphincter balloon dilation; who, when and how?

Biliary sphincter balloon dilation for biliary stone removal was introduced in 1983. In the early 1990s, several groups studied this technique further. The success rate of stone removal is comparable with that of endoscopic sphincterotomy in patients with fewer than three stones that are less then 1 cm in diameter. Fewer complications after balloon dilation than after endoscopic sphincterotomy have been noted in most studies. One study, however, showed a higher incidence of pancreatitis and, in particular, severe pancreatitis. Therefore, there is still some reluctance among endoscopists to promote balloon dilation as a routine first choice treatment. The technique, however, is accepted as the treatment of choice in patients with a bleeding tendency and those in whom the local anatomy is associated with an increased risk of complications with endoscopic sphincterotomy, such as patients with periampullary diverticula or Billroth II gastrectomy.

K Huibregtse. Biliary sphincter balloon dilation: Who, when and how? Can J Gastroenterol 1999;13(6):499-500. Biliary sphincter balloon dilation for biliary stone removal was introduced in 1983. In the early 1990s, several groups studied this technique further. The success rate of stone removal is comparable with that of endoscopic sphincterotomy in patients with fewer than three stones that are less then 1 cm in diameter. Fewer complications after balloon dilation than after endoscopic sphincterotomy have been noted in most studies. One study, however, showed a higher incidence of pancreatitis and, in particular, severe pancreatitis. Therefore, there is still some reluctance among endoscopists to promote balloon dilation as a routine first choice treatment. The technique, however, is accepted as the treatment of choice in patients with a bleeding tendency and those in whom the local anatomy is associated with an increased risk of complications with endoscopic sphincterotomy, such as patients with periampullary diverticula or Billroth II gastrectomy.
removed. The stones are then removed with a dormia basket or balloon catheter. Large concrements should first be fragmented by lithotripsy. Cannulation of the bile duct after EBD may be difficult in some patients. It is imperative that the wound of the EBD is not excessively traumatized by forcefully pushing the dormia basket or other device. The papilla is wide open after EBD, and cannulation should be easy when the opening is gently probed by the different devices.

RESULTS
To compare the results and complications of EBD and EST, randomized trials are imperative. Two of these studies have been completed. One is the Amsterdam single-centre study (8), and the other is the American multicentre study, which has only been published in abstract form (9).
In the Amsterdam study, stones of all sizes were completely removed in a single endoscopic session in 89% of EBD patients. The success rate of EBD was comparable with that of standard EST and stone extraction. However, mechanical lithotripsy was required more often after EBD than after EST. When Bergman et al (8) looked into the subgroup of patients with small stones and fewer than three stones, their results and those of the American study were comparable (98% and 100%). The lesson to be learned from these series is that, in patients with smaller and fewer bile duct stones, EBD nearly always allows successful stone removal. In patients with larger or multiple stones, the bile duct can be successfully cleared in the majority of patients after EBD, but lithotripsy is required in about 50% of patients and an additional sphincterotomy or repeat endoscopic retrograde cholangiopancreatography is needed in 15% to 30% of patients. With comparable success rates, the choice between EBD and EST should, therefore, be based on the rate of complications, and on the relative efforts and costs of the two procedures.

COMPLICATIONS
In the Amsterdam study, the rate of early complications after EBD was lower than that after EST (17% versus 24%). The difference, however, was not statistically different. No significant bleeding was observed after EBD in over 550 reported patients. Therefore, EBD is particularly suitable for patients with an increased risk of bleeding.
In the study by Bergman et al (8), 7% pancreatitis was observed in both the EBD and the EST groups. In the 550 reported patients, the overall pancreatitis rate was 5.7%. In the American study, the pancreatitis rate was 11%, with four cases of severe pancreatitis, of whom two died.
Several differences between the Amsterdam and the American study may shed light on this difference in pancreatitis rate. The mean age of the patients differed substantially (Amsterdam 72 years; American 45 years). Because age is an independent risk factor for the development of post-ERCP pancreatitis, the difference in pancreatitis rates may be a re-sult of the selection of patients. It is, however, important to realize that the younger study population had exactly the characteristics that, in theory, make it the most suitable population for EBD -patients with smaller bile duct stones that allow for easy and effective stone removal after EBD and patients of a relatively young age who can benefit most from the preservation of sphincter function.
The results of the American study may better reflect the results and complications of EBD in practice. The Amsterdam study was performed by very experienced endoscopists, whereas the multicentre American study was performed by endoscopists with different levels of experience. Furthermore, there is a learning curve associated with EBD, and some centres contributed only a few patients to the entire study.

WHAT IS THE CURRENT STATUS OF EBD?
The theoretical advantage of sphincter preservation after EBD, which is particularly applicable to young patients, is thought by many endoscopists to be outweighed by the suggested increased risk of pancreatitis. The presence of risk factors for bleeding seems to be a clear-cut indication for EBD. In addition, EBD is a valid and may be a more safe option in patients in whom the local anatomy makes a sphincterotomy more risky or impossible -for example patients with periampullary diverticula or Billroth II gastrectomy (10). Further studies may show EBD to be indicated in a wider range of patients.