194 The Korean Journal of Internal Medicine Vol. 24, No. 3, September 2009 have originated solely or directly from EPST. Jacobs et al. [10] conducted a long-term follow-up study at a single institution (n=171, 18-124 months) and reported that the reprocedure rate due to findings such as restenosis was 9.9% (17/167) after a mean period of 7 months (range 0.5- 36 months). In the current study, however, late comp- lications were noted in 2.1% (1/46) of the cases, a considerably smaller number. These results may have originated from selection bias due to the small number of enrolled patients and because many were lost to follow- up (12/46, 26%). Slight differences in the incidence of complications seen in other studies may also have been due to the heterogeneous characteristics of the subjects. In the current study, a single investigator performed the procedure at a single institution and conducted the follow- up study. The results showed that EPST did not cause late complications requiring treatment. The success rate for EPST was 95.7% (44/46), similar to that reported in other studies; thus, EPST was considered to be a relatively safe procedure. This might not have been attributable to EPST being a technically simple procedure, but occurred because many experts who have experience in EST preferentially attempt to use EPST. In other words, when physicians carry out endoscopic therapy at the pancreatic duct, they are already experienced and can thus be expected to have lower complication rates. Various proposals have been made regarding whether EST or EPST should be preformed first. A theoretical basis for the concomitant use of EST with EPST is that the swelling of the opening of ampulla can cause bile duct stenosis and cholangitis due to thermal injury resulting from the EPST procedure [4,5]. Therefore, the cutting wave, rather than the coagulation wave, is recommended to be used more frequently [6]. In the group in which EPST followed EST versus the group in which EST was preceded by EPST, this is advantageous in that a papillotome could be readily inserted and the scope of the EPST incision could be accurately measured because the opening of the pancreatic duct could be clearly disclosed [6,13]. Fuji et al. stated that the reason for the preceding use of EPST is that determining the scope of the incision is difficult due to damage to the hooding fold in cases when EST is per- formed first [7]. Recent randomized controlled trials have shown that EST is not an essential procedure, but that the procedure should be determined based on the status of bile duct prior to the procedure in cases in which EPST is needed [8]. In the current study, the incidence of complications was similar between the group with EPST alone and the group experiencing EPST with EST. The incidence of complications was not lower in the EPST with EST group compared to the EPST-alone group. As described here, the reason why no significant difference was detected in the incidence of complications may have been due to selection bias occurring in such cases; the comparison was based on the same patient condition not being present between the EPST with EST group and the EPST-alone group and patients who concurrently had biliary disease prior to the procedure being included in the EPST with EST group. Various opinions exist regarding the incidence of complications following pancreatic drainage and the rationale for it. Elton et al. reported that the insertion of pancreatic duct or nasopancreatic drainage could reduce acute complications [9]. Through an analysis of 572 cases of EPST, Hookey et al. maintained that pancre- atic drainage was needed to lower the intrapancreatic pressure generated by papillary edema following EPST [16]. This view has been challenged, however, and many negative opinions exist regarding whether nasopancreatic drainage does indeed reduce complications [10,17]. In contrast, pancreatic drainage has been reported to reduce the occurrence of acute complications in some cases, including SOD [9,15]. However, in the current study, no significant difference was found in the incidence of complications between the group in which pancreatic drainage was performed and the group in which it was not. In contrast, the occurrence of hyperamylasemia increased in the group in which pancreatic drainage was performed. These findings may be the result of stimulation of the pancreatic duct due to the insertion of a pancreatic stent or nasopancreatic drainage in severe pancreatic stenosis or cases in which a small pancreaticolith was present. Indications for EPST in the current study included chronic pancreatic diseases, such as chronic pancreatitis, pancreatic cancer, and pancreatic divisum. In fact, the incidence of complications apparently increased following pancreatic drainage. Of the indications in the current study, the usefulness of pancreatic drainage following papillectomy could not be statistically evaluated because of the small number of enrolled patients. Other limitations of the current study include the following: (1) The current study was designed as a retrospective analysis and this may have caused selection bias, leading to statistical error. (2) The follow-up period was substantial. Due to the small number of enrolled