In the 62 cases, standard PD was performed for 25 patients, PD with extended lymphadenectomy for 27 patients, and PPPD for 10 patients. One patient with gastric cancer invading the peripancreas region underwent radical gastrostomy and PD with extended lymphadenectomy. In all cases, two drainage tubes were placed posterior to the biliary and pancreatic anastomoses.

The selection of various pancreaticojejunal anastomotic techniques was based on pancreatic duct size and texture of the remnant pancreas. A duct-to-mucosa pancreaticojeju-nostomy was performed for patients with a hard pancreas and a dilated pancreatic duct (diameter ≥3 mm) (Figure 1). Posterior suture was achieved with 3-0 silk sutures between the posterior capsular parenchyma of the pancreatic remnant and the seromuscular layer of the jejunum. At the site for anastomosis to the main pancreatic duct, a small opening was made on the antimesenteric side of the jejunal wall according to the site and diameter of the pancreatic duct. Then anastomosis between the pancreatic duct and jejunum (all layers) was performed with 6-0 Prolene interrupted sutures at intervals of approximately 1 mm, from the posterior layer to the anterior layer, with all knots out of the anastomosis. Next, suture of the anterior side of the anastomosis between the pancreatic capsular parenchyma and the jejunal seromuscular layer was made by the same technique as used for the posterior side. No pancreatic duct drainage was used in cases undergoing duct-to-mucosa anastomotic technique (Figure 2). A traditional end-to-end or end-to-side invagination pancreaticojejunostomy was performed for patients with a soft pancreas and a non-dilated duct. The pancreas remnant was invaginated into the jejunum by about 2 cm, and two-layer sutures were performed interruptedly, with an internal duct stent tube inserted in the pancreatic duct.

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Figure 1 End-to-side duct-to-mucosa pancreaticojejunal anastomosis.

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Figure 2 Duct-to-mucosa pancreaticojejunal anastomosis. A: Posterior suture with 3-0 silk sutures between posterior capsular parenchyma of the pancreatic remnant and the seromuscular layer of the jejunum. B: Posterior layer anastomosis with 6-0 Prolene interrupted sutures between the pancreatic duct and jejunum (all layers). C: Anterior layer anastomosis with 6-0 Prolene interrupted sutures between the pancreatic duct and jejunum. D: Anterior suture with 3-0 silk sutures between anterior interrupted sutures between the pancreatic duct and capsular parenchyma of the pancreatic remnant and the seromuscular layer of the jejunum.

Prophylactic use of somatostatin after PD was based on the experience of the surgeon and satisfactory degree of the anastomosis. Octreotide was used for 5-7 d postoper-atively, 0.3 mg per d by subcutaneous injection.

Pancreaticojejunal anastomotic leakage was defined as: (1) discharge from the postpancreatic drain ≥50 mL/d after postoperative d 3, and (2) an amylase level of drainage fluid exceeding three times of the serum concentration.

Patients were divided into two groups according to the above criteria: 10 cases with postoperative pancreaticojejunal anastomotic leakage (leakage group) and 52 cases without leakage (nonleakage group). Seven general factors and six intraoperative clinical factors with the potential to affect the incidence of pancreaticojejunal anastomotic leakage were analyzed. Statistical computations were done with the SPSS10.0 software. Data were expressed as mean±SE, and percentage was used to express grouped data. The two groups were first compared by the univariate statistical tests, t-test, rank sum test, χ² test or Fisher’s exact test, when applicable (Tables 2 and 3). Logistic regression was then used to determine the effect of multiple factors on pancreatic leakage (Table 4). P less than 0.05 was considered statistically significant.

Of the 62 patients, 10 (16.1%) were identified as having pancreatic leakage after operation. Other major postoperative complications included delayed gastric emptying (eight patients), abdominal bleeding (four patients), abdominal abscess (three patients) and wound infection (two patients). Overall surgical morbidity was 43.5% (27/62). One patient died of massive abdominal hemorrhage associated with pancreatic fistula 10 d after operation, and two died of abdominal bleeding within 3 d after operation. The hospital mortality in this series was 4.84% (3/62), and the mortality associated with pancreatic fistula was 10% (1/10). One patient required reoperation because of abdominal bleeding, but no pancre-aticojejunal anastomotic leakage was found in this patient.

General risk factors were compared for patients with or without pancreatic leakage (Table 2). Patient age, gender, history of jaundice, preoperative nutrition, pathological diagnosis and the length of postoperative stay were similar in the two groups. The incidence of pancreatic fistula was 20.7% (6/29) in the 29 patients who received the prophylactic use of octreotide treatment after surgery, compared to 12.1% (4/33) in the 33 patients who did not undergo somatostatin therapy, and no statistical difference was found in the two patient groups. Moreover, multivariate logistic regression analysis showed that none of these factors seemed to be associated with pancreatic fistula.

Two intraoperative risk factors were found to be significantly associated with pancreatic leakage: pancreatic duct size and texture of the remnant pancreas. The incidence of pancreatic leakage was 4.88% in patients with a pancreatic duct size greater than or equal to 3 mm, and was 38.1% in those with ducts smaller than 3 mm (P = 0.002). The pancreatic leakage rate was 2.94% in patients with a hard pancreas, and was 32.1% in those with a soft pancreas (P = 0.004). Operative time, blood loss and type of resection were similar in the two patient groups. The incidence of pancreatic leakage was 6.25% (1/16) in patients with duct-to-mucosa anastomosis, and was 19.6% (9/46) in those with traditional invagination anastomosis. Although the difference of pancreatic leakage between the two groups was obvious, no statistical significance was found. This may be due to the small number of patients with duct-to-mucosa anastomosis.

The three factors affecting pancreatic leakage were further analyzed by multivariate logistic regression. Both pancreatic duct size and texture of the remnant pancreas were demonstrated to be independent risk factors (Table 3). Patients with a small pancreatic duct or a soft pancreas were at high risk of pancreatic leakage.

All the 10 patients who developed pancreatic leakage were diagnosed on the basis of the total amount and concentration of amylase in postpancreatic drainage exudate. One patient had abdominal massive hemorrhage, and two had abdominal abscess, the rest were successfully managed by conservative treatment. In five patients, a prolonged drainage duration for 4 wk after surgery was required. Octreotide was administered to five patients, including two with ineffective drains requiring another percutaneous drainage.

Risk factors for pancreatic leakage include general factors (age, gender, jaundice, malnutrition), disease factors (pancreatic pathology, pancreatic texture, pancreatic duct size, pancreatic juice output) and procedure-related factors (operative time, resection type, anastomotic technique, intraoperative blood loss). In addition, surgeon experience has been shown to correlate with pancreatic anastomotic leakage rate, and prophylactic use of somatostatin has also been reported in recent literature to influence pancreatic leakage.

It has been widely accepted that a fibrotic pancreatic remnant in patients with chronic pancreatitis facilitates the pancreaticoenteric anastomosis, whereas a soft and friable pancreatic parenchyma makes the anastomosis difficult to perform. Yeo et al[10], found that there was a strong association between the pancreatic texture and pancreatic leakage. None of the 53 patients with hard pancreatic remnants developed pancreatic leakage, whereas 25% (19/75) of patients with soft pancreatic texture were complicated by pancreatic leakage. Hosotani et al[11], reviewed 161 patients who had undergone PD and reported a fistula rate of 11% (17/161), finding that pancreaticojejunostomy anastomotic technique, pancreatic texture and pancreatic duct size were substantial risk factors for pancreatic leakage after PD. In a study by Marcus et al[12], male sex was found to be a significant factor predisposing pancreatic fistula[15]. A recent study by Yeh et al[13], identified jaundice, creatinine clearance abnormality, and intraoperative blood loss as significant risk factors for leakage. Matsusue et al[14], found that advanced age (>70 years) was an adverse factor for pancreatic leakage.

Inhibition of exocrine pancreatic secretion may reduce the anastomotic fistula rate after PD. In recent years, more importance has been attached to prophylactic use of somato-statin after PD, but no consensus has been achieved. European studies found that prophylactic octreotide in pancreatic resection could reduce total morbidity rate or pancreatic fistula rate, though none of them demonstrated a decrease in the overall mortality rate[15-18]. In another report, a significantly lower pancreatic fistula rate was observed with the use of octreotide among patients who underwent distal pancreatectomy or local pancreatic resection, whereas no statistical difference was noted between octreotide and placebo groups in patients who underwent PD[15]. Yeo et al[10],recently randomized 211 patients who underwent PD into saline control and octreotide groups. The pancreatic fistula rate in the octreotide group was 11%, and 9% in the control group. The authors concluded that prophylactic use of octreotide after PD could not reduce the pancreatic fistula rate[10]. Poon et al[19], studied the meta-analysis of six prospective randomized trials on the prophylactic use of octreotide in pancreatic resection and published them as full reports in the literature from January 1990 to December 2000. The meta-analysis did not show any beneficial effect of octreotide on pancreatic anastomotic leakage rate.

In this study, we analyzed 13 general or intraoperative factors. Two intraoperative factors were significantly associated with the risk of pancreatic leakage: pancreatic duct size and texture of the remnant pancreas. Multivariate analysis also revealed that the two factors turned out to be independent risk factors. Prophylactic use of octreotide after PD did not result in a decline of the pancreatic fistula rate.

Management of the pancreatic remnant after PD is regarded as the key point to reduce pancreatic leakage. Various recons-truction techniques have been developed to diminish pancreatic fistulae, such as duct-to-mucosa pancreatico-jejunostomy, invagination pancreaticojejunostomy, pancreati-cogastrostomy, use of a transanastomotic stenting tube, and their modifications. Ligation or obliteration of the pancreatic duct has not been popularized as they abolish the pancreatic exocrine secretion, with still a high incidence of pancreatic leakage[20-22].

Reviewing various techniques of pancreaticojejunal anastomosis in the literatures published over the last decade, Poon et al[19], found that duct-to-mucosa anastomosis was a safer technique than invagination anastomosis. Marcus et al[12], found that duct-to-mucosa anastomosis was associated with a low pancreatic fistula rate in low-risk patients with a dilated pancreatic duct or a fibrotic pancreas, whereas end-to-end invagination technique was safer in high-risk patients with small ducts or a soft friable pancreas. Suzuki et al[23], selected various pancreaticojejunostomy techniques according to the pancreatic texture and duct size, and obtained an overall pancreatic leakage rate of 8% (4/50). All of the patients who developed pancreatic fistulae were all with a small duct and a soft pancreas. In that series, the incidence of pancreatic leakage rate was 6.25% in patients who underwent a duct-to-mucosa pancreaticojejunal anastomosis, compared to 19.6% in invagination group. The difference, of course, resulted from the variation of anastomotic techniques; while all of the patients who received the duct-to-mucosa anastomosis, on the other hand, were with a dilated pancreatic duct (≥3 mm) or a soft pancreas. Therefore, both of the two factors might be associated with the discrepancy of the pancreatic leakage rate in the two groups.

There has been no conclusion as to whether a pancreatic duct stent for internal or external drainage can reduce the pancreatic leakage rate after PD. According to the authors who recommended it, a stent might help drain the pancreatic secretion juice from the anastomosis, and allow a more precise placement of sutures, thus protecting the pancreatic duct from injury and reducing fistula rate[24-27]. Some investigators found a few drawbacks to this method, such as accidental removal of the stent, obstruction or bending of the stenting tube, which might increase the incidence of pancreatic leakage. However, the overall pancreatic leakage rate in patients with a pancreatic stent was found to be similar to that in patients without a stent[28]. Therefore, as far as invagination anastomosis is concerned, it is safer to use an internal drainage stent for patients with a small pancreatic duct and a soft pancreas.

Duct-to-mucosa pancreaticojejunal anastomosis was first used by Cattel in 1943. This technique allows direct contact of the pancreatic duct with jejunal mucosa, preventing direct contact of pancreatic juice with the cut end of the pancreas and thus helping healing of the mucosa, protecting the anastomosis by embedding the pancreatic remnant under jejunal serosa. Therefore, duct-to-mucosa anastomosis is a theoretically more rational technique to avoid pancreatic fistulae. Since it is technically difficult to perform, duct-to-mucosa pancreaticojejunal anastomosis was previously recommended for patients with a dilated pancreatic duct, whereas in recent years this technique has been preferred regardless of the diameter of the pancreatic duct[11,29]. Hosotani et al[11], using multivariate analysis found that only pancreaticojejunal anastomosis technique turned out to be an independent risk factor and duct-to-mucosa anastomosis pancreaticojejunostomy reduced the risk of pancreatic leakage after PD (odds ratio = 4.15). In our hospital, invagin-ation pancreaticojejunal anastomosis was performed for patients with either a dilated or a non-dilated pancreatic duct before 2000, with a consistent high pancreatic leakage rate. From 2000, duct-to-mucosa pancreaticojejunal anasto-mosis has been performed for patients with a dilated pancreatic duct, and the pancreaticojejunal anastomotic leakage rate has declined significantly when compared with previous invagination anastomosis, though no statistical difference was found in the present study.

Based on accumulated evidence so far, no conclusion could be drawn to appraise various anastomotic techniques, since most pertinent articles were retrospective studies. In prospective studies, most were not randomized controlled trials. On the other hand, anastomotic leakage rate is greatly related to the surgery technique and experience, which cannot be easily compared among different institutions. The need for a prospective randomized controlled trial by the same surgeons to evaluate various anastomotic techniques is highlighted. In conclusion, anastomotic techniques should be selected based on the status of the remnant pancreas intraoperatively: duct-to-mucosa anastomosis without a pancreatic duct stent for patients with a dilated pancreatic duct (≥3 mm), and invagination anastomosis with an internal drainage stent for patients with a small pancreatic duct and a soft pancreas.