The management strategy associated with the optimal clinical outcomes for patients with pancreatic trauma remains ambiguous. Previous retrospective studies were mostly descriptive reports on the treatment process, and some comparative studies only focused on the operative methods of different injury grades. Our study, based on the relatively large sample size in a regional trauma center, differ from these earlier studies, and as a consequence the possibility to compare novelly the outcomes of PCD vs LAP as initial management strategies in blunt high-grade patients with stable hemodynamics and no diffuse peritonitis. This study firstly demonstrate that the initial PCD without open the retroperitoneum significantly reduces the incidence of severe complicates and does not require more invasive reinterventions compared with LAP.
Both of the Eastern Association for the Surgery of Trauma (EAST) and the results from an international conference consensus recommended OM for grade III/IV pancreatic injuries, because failure of NOM leads to treatment delays and increased complications.[22, 23] However, the only two consensus reports so far are based on weak evidence. In addition, the results of the conference consensus put forward the criteria of NOM was that patients be stable and without associated organ injuries requiring LAP, and they suggested that PCD and endoscopic management might be the treatment options in selected centers with advanced skills. Kong et al found that endoscopic management could improve success rate of NOM and lower the incidence of pancreatic-related complications in hemodynamically stable patients with blunt pancreatic trauma, however, the premise was that strictly defined selection criteria should be used for NOM . It’s difficult to pool findings from these studies due to heterogeneity in study participants, interventions, and comparison groups. We clearly defined different groups, conducted a comparative analysis, and adjusted for the effects of confounding and selection bias. Our results extending previous research and indicating significant improvement in the clinical outcomes with the use of NOM strategy based on initial PCD.
The reduced risk of severe complications for PCD seen in this study is potentially attributable to several factors. First, it is well known that in various diseases, minimally invasive techniques bring less surgical stress than LAP, resulting in lower systemic proinflammatory responses . Second, the more pronounced proinflammatory response invoked by LAP may cause organ failure or worsen pre-existing organ failure, especially in critically ill patients who are already suffering from a severe multiple organ injuries, and these patients have a series of complex pathophysiological conditions of serious posttraumatic internal environment disorders and hypoimmunity . More importantly, external drainage of initial PCD combine with the internal drainage of subsequent ERCP-guided stent placement achieves the favorable drainage effect, which can reduce various complications [27, 29, 44]. The retroperitoneal space is like Pandora’s box. Opening this space to expose the pancreas, the normal anatomy is destroyed, just like opening the magic box. Leakage of pancreatic juice and aseptic peripancreatic fluid collection are no longer limited to this space, which spreads to the abdominal cavity to form pancreatogenic ascites . On this basis, LAP may increases the chance of infection, damaging the peritoneal defense barrier, and causing pancreatogenic peritonitis. Combined with the tissue erosion caused by activation of pancreatic enzymes, can lead to fatal complications. PCD as the first step, which can quickly relieve intra-abdominal hypertension, drain peripancreatic fluid collections and so on. In the meantime, it also avoids traditional surgical drainage and reduces the risk of systemic and local complications . Subsequently, ERCP-guided stent placement can bridge the ductal disruption and reduce the incidence of fistula by decreasing intraductal pressure and promoting antegrade flow of pancreatic juice. It has been successfully used to heal MPD disruptions and treat the pancreatic-related to complications in some reports [32, 47].
Our results suggest that patients with blunt high-grade pancreatic trauma who are haemodynamically stable and no diffuse peritonitis should undergo initial PCD instead of LAP. Although the LAP group had poor pathophysiological conditions in pre-intervention (i.e., higher Apache Ⅱ peak score, more concomitant injuries, and older), we still saw that the LAP group had a high risk of worse outcomes than the PCD group after propensity score matching and weighting. Similar to the motality was 9.2% (11/119) in our study, the Western Trauma Association (WTA) Multicenter Trials Group on Pancreatic Injuries found that the motality was 7% (30/426) in high-grade injuries. We did not find significant difference in mortality between the two groups. These patients, who are in a relatively stable clinical condition, seem capable of sustaining the larger surgical stress and proinflammatory hit induced by LAP. In addition, these patients might benefit from the improvement of care capacity for severe trauma and critical illness. Another explanation may be that, due to their lower a priori risk of death, the sample size in this study is not enough to detect the difference in death between the two groups.
Looking from an overall perspective, the mean number of reinterventions per patient did not differ between two groups. Moreover, the LAP group had a higher rate of reoperation compared with the PCD group (38.9% vs 24.1%) and more severe complications, which indirectly reflected that opening the retroperitoneum may leads to severe adverse events requiring invasive reinterventions. Addison et al compared 29 patients underwent OM with 32 patients underwent NOM, and found that patients who underwent OM were more severely injured, had higher mortality (27.6% vs 3.1%), and suffered more complications . The incidence of renal failure was higher in the LAP group. The results of our previous study also showed that renal failure was significantly associated with the risk of mortality after underwent LAP . Furthermore, compared with the PCD group, the LAP group had a higher incidence of pancreatic-related complications (i.e., pancreatic fistula grade B/C, hemorrhage grade B/C, other gastrointestinal fistulas, and intra-abdominal abscess). Pancreatic leakage, caused by high-grade pancreatic trauma, can spread in the retroperitoneal space and along this space to the abdominal cavity . In the process of multiple diffusion pathways, pancreatic enzyme corrosion and cross fascia diffusion of inflammation lead to a series of pancreatic-related complications. Unfortunately, opening the retroperitoneal space through LAP is likely to accelerate this process. Another notable difference between two groups was the significantly higher rates of pancreatic pseudocyst in the PCD group. This finding is consistent with those of some previous studies. Koganti et al found that the development of pseudocysts in haemodynamically stable patients is associated with the success of NOM . Other studies have demonstrated shorter LOS in NOM patients, and we did find a silimar results in the PCD group . The longer LOS in the LAP group is not surprising, since it was related almost exclusively to severe postoperative complications. The conversion rate of LAP was 24.1% (7/29) in the PCD group. Ando et al found that the conversion rate was 40% (4/10) after underwent the initial PCD or stent placement . We believe that this combination of percutaneous peripancreatic external drainage and the bridge stenting-based internal drainage facilitated the success of NOM, and can avoid LAP to a certain extent.
Given the expertise of NOM strategy based on initial PCD is absent and the patient is clinically unfit for transport to a tertiary referral centre, LAP may still be acceptable. In patients with grade III injuries, the incidence of severe complications was significantly higher in patients who underwent operative drainage alone than in patients underwent distal pancreatectomy (100% vs 50%, P＜0.05). Therefore, we suggested that distal pancreatectomy is a valid option for grade III injuries. This result validates the recommendations of most management strategies [14, 15, 22]. Patients with grade IV injuries who underwent operative drainage alone also had a higher incidence of severe complications (68.3%). Lin et al found that peripancreatic drainage can be used as an alternative measure for grade Ⅳ injuries, however, drainage alone is not adequate and further stenting or reoperation is required due to the higher incidence of complications . Regrettably, since partial pancreatectomy was not observed in grade IV injuries, we are unable to talk about this point and these constitute important aims for future study.
A varied number and combination of interventions were adopted in managing the 119 patients in this study. Of the patients requiring a second or third procedure in the form of LAP or PCD, the majority of cases were necessary reinterventions for complications. Our study focuses on the comprehensive PCD-based strategy rather than on one specific interventions measures. Seven patients were converted to LAP due to failure of the initial PCD strategy. To avoid a selection bias, we chose to include them in the PCD group because we wanted to present the overall phenomenon of pancreatic trauma management in the NOM strategy. This gives what is essentially an intention-to-treat analysis of a PCD-based strategy. As we have discussed previously, patients with high-grade pancreatic trauma are a complex population, with no one-size-fits-all management strategy. It is therefore expected that in the evolution of treatment concept, a shift will occur from OM to NOM to an increase in the use of endoscopic and interventional radiological procedures for selected patients.
This study has several limitations. It is possible that measurement errors and hidden or unknown confounding factors, which are not accounted for in our analyses, may have influenced results. Using per-protocol predefined case record forms for data extraction and well-defined patient inclusion criteria, however, reduced the risk of measurement errors to a minimum. For another, the included cohorts did not capture data on pretherapeutic imaging, which may influenced the decisions to perform PCD or LAP. Second, this is a single-center retrospective study spanning 13 years. Time periods is neither included in univariate nor in multivariate analysis. However, it may have been a factor to adjust for per se. Because the konwledge and practice of trauma care, imaging technology and lifesaving interventions have developed significantly during this period. The PCD group might have benefited from overall improvements in care, not specifically related to the management strategy. In addition, our LAP cohort represents a group of patients benefiting from years of experience with that technique, and the patients comprising the PCD group include our first patients treated with the techniques of PCD and ERCP-guided stent placement. This might have biased the comparison against the PCD group. Despite the inherent limitations exist in our study, it still provides a certain degree of evidence to guide clinical decision-making for this serious and complex disease.