PD represents the ideal treatment for periampullary lesions. Complications related to pancreatic duct reconstruction are still the leading cause of morbidity and mortality.
Evidences support a strong correlation between surgical outcomes and hospital volume in pancreatic surgery [23–26].
Mortality can be used as an indicator of quality of surgery for PD, but literature lacks an agreed description of the standard of care for such a complex procedure .
Surgical outcomes after PD are better in centres performing more than 50 resections per year with a reported overall mortality of less than 5%, compared with a mortality rate of 12.4% in low-volume centres [25, 28]. Centres can be considered for pancreatic surgery accreditation if they meet the requirement of 50 pancreatic procedures (including PD) over 3 years with a mortality rate lower than 50% .
In a recent study of Krautz et al., the mortality rates reported in Germany ranged from 6.5% in very high-volume hospital to 11.5% in very low-volume ones . Considering only high-volume centres, mortality rates can be below 2% .
Similarly, the overall mortality rate in more than 1500 PD performed in Italy was reported to be as high as 8.1% . The authors classified hospitals according to volume in low-volume, (< 5 PD/year), medium-volume (6–13 PD/year), high-volume (14–51 PD/year) and very high-volume (> 90 PD/year) centres, and found that post-operative mortality rate decreased progressively from 12% (low-volume hospitals) to 2.6% (very high-volume hospitals) .
Our results show an overall pancreatic surgery-related mortality, as high as 8.3%, which is lower compared to the observed mortality for low-volume centres .
However, in the experience of a high-volume centre, postoperative mortality after PJ seemed to be higher than after DO (6.8% vs 2.4%) .
Pedrazzoli in a large systematic review on Pancreaticoduodenectomy and pancreatic fistula analysed 162 articles involving 54,232 patients. The review shows 4813 Grade A (8.9%), 4830 Grade B (8.9%), and 1872 Grade C (3.5%) POPFs with a mean overall fistula rate of 21.3%. A huge variability of Grades A and B POPFs varied from less than 2% to more than 20% with a minimum of 0% and a maximum of 42.5% for Grade A and a minimum of 0.7% and a maximum of 33.3% for Grade B POPF. Grade C POPFs arises from 1% to more than 9% with a maximum of 13.6% .
It has been suggested that avoiding an anastomosis of the pancreatic duct by means of duct occlusion could minimize anastomosis-related morbidity, especially in low-volume centres [17, 18, 32, 3]. The aim was to obtain a “pure” pancreatic fistula with no activation by bile and/or enteric juice, thereby reducing the risk of life-threating complications.
Di Carlo et al showed that DO procedure was feasible and less time-consuming than PJ, although it could be associated with higher fistula rates. However, POPF could not be clinically relevant probably due to the absence of a pancreatic enzymes activation .
In our experience the overall incidence of POPF was 66.6%. This observation is consistent with the experience of Tersigni et al, who observed a higher rate of POPF after DO (45.4%) compared to end-to-end PJ anastomosis (15.6%) and to end-to-side PJ anastomosis (11.3%), with a similar incidence of Grade C fistula in all the groups (3.1% after end-to-end PJ anastomosis, 2.3 after end-to-side anastomosis and 3.0% after DO) . In our hands only 4 patients (8.3%) had a life-threating POPF. In a recent study comparing 54 patients operated on in a high-volume centre with 44 patients operated on in a low-volume centre over five years, there were no statistical differences in the incidence of POPF between the two groups (30% vs 27%, P = 0.826) . All patients in this study had a PJ after PD. Interestingly, the rates of Grade C fistula were 25% in the high-volume centres and 17% in the low-volume centre. These figures are slightly higher than those observed in our centre with DO. Others have reported that DO has higher postoperative morbidity and mortality, even if not statically significant .
Consistent with other reports, in our patients a soft pancreatic texture was associated with a significantly higher incidence of POPF (overall 27.1% of POPF with soft pancreas vs. 6.25% of POPF with fibrotic pancreas, P = 0.0068).
Moreover, when considering only clinically relevant POPF, we had only 2 POPF (4.2%) with fibrotic pancreas versus 15 POPF (31.4%) with soft pancreas (P < 0.005).
In a recent prospective randomised control study  compared POPF following PO in high risk patients for pancreatic fistula vs PJ after PD for low risk patients for pancreatic fistula, mortality after PO was 5.9% and 2.0% after PJ anastomosis, in our serie 90-day mortality related to significant POPF was (3/48) 6%, so mortality might be considered superimposable with other authors who performed DO (Table4) .
He et al. analysed RCTs and OCSs, where were related different treatment of pancreatic stump and maojor outcomes after PD or pylorus-preserving PD for malignant or benign pancreatic tumor, chronic pancreatitis, or extra- pancreatic tumors (periampullary, biliary or duodenal)
The objective of the metanalysis was a comparison between PJ and PG using quantitative data on PF and overall complications. PD without anastomosis, or duodenum-preserving pancreatectomy was excluded. ( He et. al)  We shall underline metanalysis by He et al. reported a lower mortality index performing PG and PJ, but these data were published by high volume and referral centres for pancreatic surgery , the same paper reported data by Duffas et al. showing in their experience an incidence of death after PG 10 (12%) and PJ 7 (10%). A summary of these findings is depicted in Table 5.
Our incidence of reoperation was quite high 19.6% (Table 4), it was linked to Grade C POPF in 5 patients (45.4% of C grade fistula patients) our incidence is similar to what other authors reported in literature either after DO either after PA [20-21-23-27], but as depicted in the Table 5, high volume referral centre showed lower rate of reoperations.
In our opinion, in patients with a higher risk for POPF (soft pancreas, dilated pancreatic duct) DO can be a safer option, ideally suitable in low-volume centres.
Four of our patients (8.3%) had postoperative haemorrhage, and all of them needed return to operative room. Interestingly, in only two patients (50%) haemorrhage was a consequence of POPF (all grade A). In the other two cases the bleeding originated from a small vessel from the portal vein and the gastroepiploic artery. The overall incidence of POPF-related bleeding was 4.2%, which is in line with other experiences .
Our length of stay was 28 days, higher than those observed in other experiences [7, 18]. Of note, availability of post-discharge opportunities, financial problems, low human resources and patients wish could affect this figure.
More than 80% of patients needed pancreatic enzymes supplementation due to postoperative pancreatic insufficiency. This facet is consistent with others [15–17] however, Tran et al reported that the need for enzyme supplementation one year after surgery was not related to the type of reconstruction  Probably, pancreatic exocrine insufficiency is more related to the pancreatic atrophy/fibrosis and preoperative texture than to DO or PJ [15–17].
In our series, 9% of patients developed brittle diabetes, with only 13 patients (27.1%) developing new onset diabetes. This might confirm that DO has higher risk of new onset diabetes, even if only few patients suffer from an uncontrolled diabetes [15–17].
According to Tran et al., the incidence of endocrine insufficiency is significantly higher after DO compared with PJ at 3- and 12-month follow-up after surgery (P = 0.001 for both) .
It is clear that the outcome of complex surgical procedures may not only rely on technical aspects of surgery, but it is also affected by resource availability. However, some technical aspects can be modified and reduce the risk of life-threating postoperative complications even in low/medium volume centres.
PD can be safely performed in low-volume centres if amenities and processes typical of high-volume centres can be replicated in specialized units [34–35].
The ideal concept of reserving pancreatic surgery only to high specialized centres is probably utopian. Geographical limitations, elevated costs for the patients and their relatives, political issues, different regional health-care systems, and the opposition by medical and surgical staff determine the need to perform this surgery even in academic or tertiary referral hospitals with a limited experience in pancreatic surgery  but with all the amenities required for very complex surgery.
According to Diaz et al. although most patients who need PD bypass the nearest providing hospital
to seek care at a higher-volume hospital, nearly 25% of the patients still underwent PD at a low-volume centre .
So, considering criteria published in literature [23–26], pancreatic surgery should be centralized, this implies unavoidably an increase of interregional mobility and related health care costs, especially for patients from region of southern Italy.
During Covid-19 pandemia, as we know from the survey written by Aldrighetti et al. on HPB surgery in Italy , 72.8% of HPB centers showed a reduction of routine elective operations ≥ 50%, if we combine effects of centralization to the effects of Covid-19 pandemia we understand how difficult would be for patients to undergo pancreatic surgery in a quite fast, safe and effective way. In this situation we decided to analyze our outcomes from a low volume center for pancreatic surgery to overcome the impossibility to send patients to pancreatic surgery referral centers, considering their overload, ensuring to patients a high-quality service at the same time. Our approach led us to guarantee effective treatment and safety procedures during the critical pandemic period.
Probably, a surgical alternative such as DO during the phase of PD at higher risk of complications, i.e. the pancreatic anastomosis, can reduce the rates of subsequent morbidity and mortality with similar oncological results.