The present study including 120 patients with CR POPF indicates that ET (performed in 14%), complementary to standard treatment does not seem to be superior to standard treatment alone, healing time (59 days vs 32 days) and hospital stay (24 vs 11 days). ET seems safe but after ET the time to POPF resolution was long (34 days). Operating time ≥ 3 h, MPD diameter ≤ 3 mm, ASA 1–2, and a CRP ≥ 180 on POD 3 were independent risk factors for CR POPF.
Watanabe et al. [25] demonstrated a similar hospital stay with or without ET (40 days) and the mean healing time after ET was 46 days in 11 patients. Reddymasu et al. [28] reported healing in eight patients 44–379 days after ET. Goasguen et al. [26] evaluated ten patients (including two enucleations) who underwent ET, experiencing a POPF resolution after 1–12 days. Similarly, Grobmyer et al. [27] analyzed eight patients treated with ET and a healing was achieved after 32–84 days. Apparently, there is often a long healing time of POPF after ET with a wide variation in duration. The reason for this is not clear from current data based on small retrospective studies. In contrast to the treatment of biliary leakage, a possible downstream control with a reduction of MPD pressure after ET does not seem to be the obvious mechanism solving the problem [8, 22].
In the present study the selection to perform ET (14%) and time to intervention (8–79 days) was not standardized. In previous studies the frequency of ET in studied cohorts was 29–62% or not reported, the time duration from DP to performing ET has also varied (12–120 days) [25–28]. Thus, all studies suffer from a selection bias and a lack of uniform management. As in the present series, patients with a more severe condition may probably have been offered ET more frequently. In our study the rate of CT within the first postoperative week was 24% in the ET group corresponding with the need for CT in the presence of suspected complications as proposed in a recent randomized controlled trial [39].
Like other studies investigating the role of ET there are methodological variations regarding numbers of stents, dimensions, length of stents, and indications for repeating ET [25–28]. As in the present study, ET has sometimes not included EPS [26] and in one study stents were always inserted without EPS [28]. Moreover, as reported by others ET may also aim at draining collections, thus passing the resection line (5/17 in the present series) [25]. In the present series ET also included endoscopic ultrasound and drainage by double pigtail or lumen apposing metal stents in two patients, not obviously contributing to POPF resolution. A high rate of technical and clinical success has been reported using drainage by endoscopic ultrasound alone but similar to ERCP-based ET, the time until resolution is long [40].
Mild post-ERCP pancreatitis was the only type of complication after ET in the present series and occurred in 17.6% of the patients subjected to this procedure. Our study is small and comparison with the literature is difficult, systematic reviews have reported a rate of post-ERCP pancreatitis in unselected patients between 3.5% and 9.7% [41]. In comparison, in our cohort the aim was a pancreatic intervention in an already vulnerable situation. It may also be difficult to distinguish between what was a true complication of the ET and the development of the primary event. No complications or no “serious complications” after ET were reported by others [25–28]. Thus, it may appear that the complication rate after ET seem low and mild in character not adding an obvious burden to the already serious condition. Multiple procedures were often needed, in our series 53% underwent repeated ET. The rate of repeated ET has ranged from 10–25% in other series [25–28].
The rate of CR POPF after DP in our study was 32.6% which is in the higher range of previous reports [1, 3–5, 8, 11, 42]. Most resections in the present series were performed by open surgery and in accordance with the ISGPS guidelines, and as demonstrated in a recent meta-analysis, the surgical approach did not affect the frequency of CR POPF in our study [14, 43]. In conformity with others, we found no influence on the rate of CR POPF by the choice of closing method [3, 10]. In line with other studies, extended resection was not a risk factor for CR POPF in the present series [3, 4, 10, 21, 44]. There are conflicting results regarding the level of transection line and incidence of POPF; some reports indicate an increased risk dividing on either side of the pancreatic neck [4, 45, 46]. As reported by others, in the present study a transection right of the pancreatic neck was not related with CR POPF [3, 6, 47], but was indeed associated with ET.
Our study identified ASA-PS 1–2 status, MPD ≤ 3 mm, procedure time ≥ 3 h, and CRP ≥ 180 on POD 3 as independent factors for CR POPF. A long operation time as a risk factor has also been demonstrated by others [9, 21]. A high level of CRP on POD 3 or an increase of CRP from POD 2 to POD 3 have been found as risk factors [48]. Contrarily, elevated ASA-PS and increasing MPD diameter have been documented as risk factors by others [6, 49]. A high BMI, smoking, benign disease, younger age, male sex, and intraoperative blood loss have been associated with increased risk [3, 4, 9, 12, 48], but were not confirmed as risk factors in the present series. The ISGPS has emphasized the importance of a reliable risk score, and two scoring systems have recently been suggested [14, 49, 50].
PPH is the most serious complication after CR POPF and linked to mortality [12]. Also in the present study, PPH was more frequent in the CR POPF group with a high rate (5/17) in patients selected to ET. Although other published patient cohorts are small, PPH was not described in other series using ET [25–28]. This may indicate a different selection of patients to ET. The fatality in our ET group was caused by PPH, the patient underwent angiography and laparotomy. Three other patients successfully underwent angiographic interventions, while bleeding stopped spontaneously in the fifth patient with PPH. Thus, there is need for a multimodality treatment, including additional abdominal drainage which was frequently used in the ET group.
A limitation in the current study is the retrospective design. Interpretation of results are hampered by the lack of strict indications for ET, and non-standardized therapy (timing, procedure details, reinterventions, duration of stents). A strength of the study is the consecutive nature, all patients who underwent DP were analyzed, including a complete follow-up. The number of patients treated was small, but still we have not found any larger study and reports of ET of POPF are also scarce.