Comparison of conjoined tendon-preserving posterior approach and conventional posterolateral approach in hemiarthroplasty for femoral neck fracture in the elderly: A multicenter (TRON group) retrospective study.

BACKGROUND: Femoral neck fractures (FNF) are one of the most common traumatic injuries in the elderly. The conjoined tendon-preserving posterior (CPP) approach was developed as a modification of the conventional posterolateral (PL) approach in hemiarthroplasty (HA) for displaced femoral neck fractures (FNF) to reduce postoperative dislocation. We hypothesized that the CPP approach would result in fewer dislocations and similar functional and radiographic outcomes compared to the PL approach. PATIENTS AND METHODS: This was a retrospective multicenter (TRON group) study. We evaluated the rate of complications, and functional and radiographic outcomes for patients aged >65 years who underwent HA via the PL approach or the CPP approach from 2017 to 2019 and followed up for at least 24 months. To adjust for baseline differences between the groups, a propensity score-matching algorithm was used in a 1:1 ratio. RESULTS: We identified 135 patients who underwent HA via the PL approach and 135 patients via the CPP approach. The mean follow-up period was 32.4 ± 14.0 months. The incidence of dislocation was 6 in 135 patients (4.4%) in the PL group and 0 in 135 patients (0%) in the CPP group, and there was significant difference (p = 0.04). Operation time was equivalent between the two groups (73.1 ± 30.4 vs. 71.8 ± 30.0 min; p = 0.72). The rate of varus insertion of stems in the PL group lower than that in the CPP group (19.3% vs. 33.3%; p = 0.01). Postoperative Parker's mobility score was similar between the two groups at 12 months follow-up (6.17 vs. 6.27; p = 0.81). CONCLUSION: The CPP approach showed a significantly lower dislocation rate, similar functional outcome and more varus stem insertions compared with the PL approach in this retrospective study.

Effect of anaesthesia on cemented hemiarthroplasty -A multicentre retrospective study (TRON study).

INTRODUCTION: This study aimed to investigate the survival rate, postoperative complications, and walking ability in cemented hemiarthroplasty (HA) for displaced femoral neck fractures according to the anaesthesia method. METHODS: We conducted a retrospective study of a multicentre group (the TRON group). Three hundred fifty-eight patients who underwent cemented HA between 2015 and 2019 were selected; 289 patients of ≥75 years of age with no missing data were included. Patient background factors were matched and patients were assigned to spinal anaesthesia (SA) and general anaesthesia (GA) groups. The primary outcome was death at any time during the follow-up period. Secondary outcomes included postoperative complications and walking ability assessed using the Parker mobility score (PMS). Overall survival was evaluated using the Kaplan-Meier method, and differences were compared using the log-rank test. The incidence of each complication and PMS were compared between the two groups using Fisher's exact test. RESULTS: Overall survival during follow-up was significantly higher in the SA group in comparison to the GA group (p = 0.037). In the SA and GA groups, the survival rate at 3 months postoperatively was 98.4% and 95.5%, respectively. The incidence of postoperative pneumonia was significantly higher in the GA (p = 0.012), and PMS at 3 months postoperatively was significantly higher in the SA group (p = 0.016). CONCLUSION: The survival rate of elderly patients who underwent cemented HA was better in the SA group. General anaesthesia in cemented HA may be associated with lower life expectancy, increased incidence of pneumonia, and decreased walking ability.

Application of Extended Reality (Virtual Reality and Mixed Reality) Technology in Laparoscopic Liver Resections.

Background and purpose Laparoscopic liver resection (LLR) has recently gained popularity owing to advances in surgical techniques. Difficulties in LLR may be influenced by anatomical factors. This study presents a comprehensive overview of LLR performed using extended reality (XR) technology. Methods Six patients underwent LLR performed wearing HoloLens2® XR (Microsoft Corporation, Redmond, Washington, United States) technology. We performed dynamic contrast-enhanced CT scans before surgery and used the data to construct three-dimensional images. Results Of the six patients, two were diagnosed with colorectal liver metastases, two with hepatocellular carcinoma, and one with intrahepatic cholangiocarcinoma. The median maximum tumor diameter was 31 mm (range, 23-80 mm). One patient had liver cirrhosis, with Child-Pugh classification grade B. Anatomical resection was performed in three patients (60%), with a median difficulty score of 7 (intermediate). No conversions to open surgery were necessary. The median operative time and estimated blood loss were 444 minutes (range, 337-597 minutes) and 200 mL (range, 100-1000 mL), respectively. Postoperative complications (Clavien-Dindo classification grade II) were observed in one patient. All six cases achieved negative surgical margins. Conclusions LLR using XR technology enhances surgical visualization and anatomical recognition. The incorporation of XR technology into LLR offers advantages over traditional two-dimensional imaging.

The Safety of Laparoscopic Cholecystectomy in Super-elderly Patients: A Propensity Score Matching Analysis.

BACKGROUND: Although reports on the safety of laparoscopic cholecystectomy (LC) exist, few have included patients aged ≥ 85 years. Hence, our study aimed to evaluate surgical outcomes of LC in patients aged ≥ 85 years. METHODS: After excluding patients who underwent other types of surgeries, 583 patients who underwent LC between 2015 and 2022 were included. Patients were classified into two groups based on age: < 85 years (control group, n = 551) and ≥ 85 years (super-elderly group, n = 32). Propensity score matching (PSM) was performed based on preoperative clinical parameters, and intraoperative and postoperative outcomes were compared. RESULTS: After PSM, 28 patients were included in each group. Intraoperative blood loss (1 vs. 5 mL, respectively; P = .052) and frequency of serious postoperative complications (Clavien-Dindo class ≥ 2, 2/28 (7.1%) vs. 6/28 (21.4%), P = .252) were similar between the control and elderly groups. There was no significant difference in the length of postoperative stay (control group: 5 (4-24) days vs. super-elderly group: 7 (3-64) days, P = .236). Unfortunately, one case of pneumonia of unknown cause occurred postoperatively, resulting in the death of one patient in the super-elderly group. CONCLUSIONS: There were no clinically significant differences in the short-term outcomes of LC between super-elderly patients aged ≥ 85 years and patients aged < 85 years. Hence, LC may be relatively safe even in patients aged ≥ 85 years. However, owing to many pre-existing diseases and deterioration of physiological function, careful management during the perioperative period is desirable.

Preoperatively diagnosed intraductal oncocytic papillary neoplasm of the pancreas with prominent invasion: a case report.

Previously considered as one of the less-invasive subtypes of intraductal papillary mucinous neoplasm, intraductal oncocytic papillary neoplasm (IOPN) has recently been acknowledged as a new entity of pancreatic tumor. We herein present a case of preoperatively diagnosable IOPN invasion in the stomach and colon. A 78-year-old woman was referred to our hospital for evaluation of anorexia and gastroesophageal reflux. Upper gastrointestinal endoscopy revealed a gastric subepithelial lesion with ulcerated mucosa that required hemostasis. Computed tomography revealed a 96-mm-diameter solid tumor with a well-defined border and centrally positioned necrotic area, extending from the stomach to the transverse colon and pancreatic tail. Because it was suspected to be a pancreatic solid tumor with direct stomach invasion, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) was performed, which led to a preoperative diagnosis of IOPN. Moreover, laparoscopic pancreatosplenectomy, proximal gastrectomy, and transverse colectomy were performed. Analysis of the surgical specimen revealed that the tumor was IOPN and had invaded the stomach and transverse colon. Lymph node metastasis was also confirmed. These findings indicate that IOPN can manifest as an invasive tumor, and EUS-FNB may be equally helpful for assessing the invaded area of a cystic lesion as it is for a solid lesion.

Quick and Easy Application Method of TachoSil®ï¸ During Laparoscopic and Robotic Liver Resections.

TachoSil®ï¸, a fibrin sealant patch, is a sheet-type hemostatic agent. Therefore, it is technically demanding to put it on the target place especially in laparoscopic surgeries due to the motion restriction of straight-fixed instruments. This article describes a quick and easy technique of TachoSil application during laparoscopic liver surgeries, by sewing it to the laparoscopic gauze in advance. This method allows for one-handed operation and stress-free application even in the situation of active bleeding.

Non-Stick Liver Parenchymal Transection With Saline-Linked Bipolar Clamp-Crush Technique in Robotic Liver Resection.

Background Without satisfactory instruments, liver parenchymal transection during robotic liver resection (RLR) remains challenging. We combined the commonly used bipolar clamp-crush technique with the saline drip, achieving a comfortable liver resection without coagulated liver tissues sticking to the bipolar forceps. Methods Between December 2022 and March 2023, six RLRs were performed using the saline-linked bipolar clamp-crush method for both anatomical and non-anatomical liver resections. We assessed the safety and feasibility of our robotic liver parenchymal transection technique. Results Three of six patients were diagnosed with colorectal liver metastasis, two with hepatocellular carcinoma (HCC), and the other with intrahepatic bile duct stricture. Three of the six patients received anatomical liver resection, and the other three underwent non-anatomical liver resection. There were no conversions to open surgery. The median operative time and estimated blood loss were 406.5 minutes (196-670 minutes) and 5 ml (5-465 ml), respectively. The median length of the postoperative hospital stay was nine days (7-10 days). Postoperative complications (Clavien-Dindo classification grade II or more) or mortality were not encountered in this cohort. Conclusion We presented here our saline-linked bipolar clamp-crush method for liver parenchymal transection in RLR. By simply adding the saline drip to the commonly used bipolar clamp-crush technique, non-stick and comfortable liver parenchymal transection is now possible. This technique may help overcome the limitations of currently available robotic instruments for liver parenchymal resection.

High predictive ability of apparent diffusion coefficient value for wall-invasion pattern of advanced gallbladder carcinoma.

PURPOSE: The wall-invasion pattern classification of advanced gallbladder carcinoma (GBC) has been reported. However, its association with clinical findings remains unclear. We aimed to clarify relationships between clinicopathological characteristics, prognosis, and apparent diffusion coefficient (ADC) values of advanced GBC based on the wall-invasion pattern. METHODS: We reviewed the data of 37 patients who had undergone advanced GBC cholecystectomy at our institution between 2009 and 2021. Clinicopathological findings, prognosis, and ADC values were retrospectively analyzed. RESULTS: Based on the wall-invasion pattern, patients were classified into infiltrative growth (IG) type (n = 22) and destructive growth (DG) type (n = 15). In the DG-type, the incidence of venous invasion (P = 0.027), neural invasion (P = 0.008), and lymph node metastasis (P = 0.047) was significantly higher than in the IG-type, and recurrent-free survival (RFS) was significantly shorter (P = 0.015); the median RFS was 11.4 months (95% confidence interval, 6.3-16.5 months) in the DG-type and not reached in the IG-type. The ADC value in the DG-type was significantly lower than in the IG-type (median, 1.19 × 10-3 mm2/s vs. 1.86 × 10-3 mm2/s, P < 0.001). The area under the receiver operating characteristic curve for the ADC values to differentiate wall-invasion patterns was 0.95 (95% confidence interval, 0.87-1.00). The optimal cutoff ADC value was 1.45 × 10-3 mm2/s (sensitivity, 92.9%; specificity, 90.9%). CONCLUSIONS: The wall-invasion pattern of advanced GBC is associated with its aggressiveness and prognosis, and can be predicted by ADC values with high accuracy.

Impact of AirSeal® insufflation system on respiratory and circulatory dynamics during laparoscopic abdominal surgery.

The effect of the AirSeal® insufflation system on hemodynamic parameters, especially end-tidal carbon dioxide (EtCO2), during laparoscopic abdominal surgery remains unclear. This retrospective single-center study included 333 consecutive patients who underwent laparoscopic hepatectomy (n = 43), gastrectomy (n = 69), colectomy (n = 137), or proctectomy (n = 84) using the AirSeal®. Patient demographics and intraoperative hemodynamic parameters, such as EtCO2, peripheral capillary oxygen saturation (SpO2), and arterial systolic blood pressure (ABP), were collected and analyzed. EtCO2 was evaluated during the entire operative period (whole period) as well as the pneumoperitoneum period until specimen removal (pneumoperitoneum period). We defined "positive respiratory and circulatory responses" (positive responses) as a decrease in EtCO2 ≥ 3 mmHg in addition to decreases in SpO2 ≥ 3% and ABP ≥ 10 mmHg simultaneously, which suggest possible carbon dioxide (CO2) embolism. The median EtCO2 values of hepatectomy, gastrectomy, colectomy, and proctectomy in the whole period/pneumoperitoneum period were 37.3/37.4, 37.1/37.3, 37.4/37.9, and 38.2/38.4 mmHg, respectively. The EtCO2 of proctectomy was significantly higher than that of gastrectomy during the whole and pneumoperitoneum periods (P < 0.05). In contrast, the EtCO2 of hepatectomy was comparable to that of the other three surgeries in the whole and pneumoperitoneum periods. Meanwhile, nine (2.7%; eight hepatectomies and one proctectomy) patients showed positive responses, and one who underwent a partial hepatectomy developed a clinically manifested CO2 embolism. Positive responses occurred during venous exposure or bleeding in all nine cases. Although the EtCO2 of hepatectomy was comparable to that of the other surgeries using the AirSeal®, laparoscopic hepatectomy showed a tendency of CO2 embolism. Thus, a secure and careful surgical approach is mandatory for laparoscopic hepatectomy using the AirSeal® insufflation system.

Dissection Around the Superior Mesenteric Artery (SMA) Using LigaSure Maryland During Left Posterior Approach for Pancreaticoduodenectomy.

R0 resection for pancreatic head cancer without exposing the tumor demands complete resection of "mesopancreas". In other words, dividing the proximal jejunal artery and vein at their roots of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) respectively during pancreaticoduodenectomy (PD) is absolutely essential. We present here our standardized dissection procedures around the SMA during the left posterior approach for PD. This procedure is safe and reproducible owing to the secure sealing performance of LigaSureTM Maryland.

Standardized Methods Using EUS-guided Fine-needle Biopsy and a Minimal Medium Creates Three Pancreatic Cancer Organoids.

BACKGROUND/AIM: Recently, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has been conducted for diagnosing pancreatic ductal adenocarcinoma (PDAC), after which obtained samples were used in organoid cultures. However, no standardized method for PDAC organoid cultures exists. Therefore, to standardize or simplify sample collection and culture methods for PDAC organoids, we performed a floating culture using non-minced specimens obtained by EUS-FNB in a minimal medium, lacking growth factors or inhibitors for pancreatic organoids. PATIENTS AND METHODS: A total of 38 patients with clinically diagnosed PDAC were enrolled in the study. First, EUS-FNB was conducted using a 22- or 25-gauge biopsy needle. Then, a surplus of samples was collected for organoid formation after rapid on-site cytological evaluations of sample adequacy. Subsequently, the established organoids were compared with clinical data and pathological diagnosis, following periodic observations and evaluations for morphology. RESULTS: PDAC organoids were successfully created in 24 of the 38 cases (63.2%), including four cases with pathologically inconclusive EUS-FNB results. Afterward, PDAC organoid morphology was classified into ductal, dormant, and adhesive small cluster (ASC) types. Although the ductal and ASC types were seen separately, they were also seen together in other cases, which we named "mixed type". CONCLUSION: We propose a feasible and straightforward method for establishing organoids, especially for diagnosing PDAC, particularly when the result of EUS-FNB is pathologically inconclusive. Furthermore, PDAC organoids are morphologically classified into three types reported for the first time.

Crucial Roles of the Assistant Surgeon During Laparoscopic Left Hemihepatectomy.

Background Although left hemihepatectomy has been widely performed via the laparoscopic approach, the roles of the assistant surgeon have not been well-documented so far. We herein present our standardized procedures of laparoscopic left hemihepatectomy without Spiegel's lobe resection, focusing on the crucial roles of the assistant surgeon. Methods During laparoscopic left hemihepatectomy without Spiegel's lobe resection, countertraction by the assistant surgeon is quite important especially during isolating the left Glissonean pedicle and transecting liver parenchyma. When securing the left hepatic pedicle using the Glissonean approach, the assistant surgeon pushes Segment 4 of the liver cranially and pulls the tape encircling the hepatoduodenal ligament caudally in the opposite way, orthogonal to the direction of the laparoscopic forceps toward the left portal triad. During liver parenchymal transection, the assistant surgeon pulls the hanging tape across the left lobe of the liver in order to provide a wide and stable liver transection plane. With this standardized technique, nine cases of laparoscopic left hemihepatectomy were performed over the last two years in our department, and the perioperative data were retrospectively analyzed. Results The median age of the nine patients was 70 years (range: 58 - 84 years). Most of the patients were males (77.8%). Five of nine patients were diagnosed with colorectal liver metastasis, two with hepatocellular carcinoma (HCC), one with inflammatory pseudotumor, and the other one with hepaticolithiasis. There were no conversions to open surgery. The median operative time and estimated blood loss were 337 minutes (range: 219 - 478 minutes) and 100 ml (range: 41 - 375 ml), respectively. The median length of postoperative hospital stay was nine days (range: 7 - 16 days). Major complications (Clavien-Dindo classification grade III or more) were not encountered in our cohort postoperatively. Conclusion We presented here our standardized assistant roles during laparoscopic left hemihepatectomy without Spiegel's lobe resection, which was revealed to be safe and feasible in our cohort.

Oncological evaluation in the perioperative period using cfDNA with BRAF V600E mutation in patients with colorectal cancer.

The detection of circulating cell-free DNA (cfDNA) by liquid biopsy is reported to provide prognostic information in colorectal cancer (CRC). Although the frequency of BRAF V600E mutation in CRC is less than 10%, it is associated with poor responses to conventional chemotherapy. We conducted a prospective study to investigate the relationship between the perioperative mutant allele frequency (MAF) of BRAF V600E and tumor recurrence, and to evaluate the possibility of early detection of recurrence. Among 362 patients who underwent radical resection, cfDNA was extracted from the perioperative blood of 11 CRC patients with BRAF V600E mutation and analyzed using the digital polymerase chain reaction (dPCR) system. The median follow-up time was 22 months, and there were four cases of recurrence. Although there was no correlation between recurrence and the perioperative MAF of BRAF V600E, tumor diameter was correlated with the MAF (p = 0.024), and the MAF increased with time in two patients from whom additional samples were obtained prior to recurrence. In this study, we identified a correlation between the pathological tumor diameter and the MAF, but it was difficult to predict recurrence by measuring cfDNA with BRAF V600E mutation in the perioperative period of radical resection of CRC.

Unsupervised Phoneme and Word Discovery From Multiple Speakers Using Double Articulation Analyzer and Neural Network With Parametric Bias.

This paper describes a new unsupervised machine-learning method for simultaneous phoneme and word discovery from multiple speakers. Phoneme and word discovery from multiple speakers is a more challenging problem than that from one speaker, because the speech signals from different speakers exhibit different acoustic features. The existing method, a nonparametric Bayesian double articulation analyzer (NPB-DAA) with deep sparse autoencoder (DSAE) only performed phoneme and word discovery from a single speaker. Extending NPB-DAA with DSAE to a multi-speaker scenario is, therefore, the research problem of this paper.This paper proposes the employment of a DSAE with parametric bias in the hidden layer (DSAE-PBHL) as a feature extractor for unsupervised phoneme and word discovery. DSAE-PBHL is designed to subtract speaker-dependent acoustic features and speaker-independent features by introducing parametric bias input to the DSAE hidden layer. An experiment demonstrated that DSAE-PBHL could subtract distributed representations of acoustic signals, enabling extraction based on the types of phonemes rather than the speakers. Another experiment demonstrated that a combination of NPB-DAA and DSAE-PBHL outperformed other available methods accomplishing phoneme and word discovery tasks involving speech signals with Japanese vowel sequences from multiple speakers.

[Enhancement of Pesticide Peak Response in GC-MS in the Presence of Multiple Co-Existing Reference Pesticides].

We carried out a collaborative study in six laboratories to confirm the universality of the enhancing effect of co-existing reference pesticides on the GC-MS peak response to a target pesticide (malathion, procymidone, or flucythrinate). First, we confirmed the response enhancement of the target pesticides with increasing numbers of co-existing reference pesticides in solution. Then, using diluted green soybean matrix, we analyzed the target pesticides with two types of matrix-matched calibration, containing the target pesticides or 166 other pesticides. In both cases, the response-enhancing effect of co-existing pesticides was confirmed in all laboratories. The enhancement was reduced by addition of green soybean matrix to the sample and calibration solutions. Our results show that it is necessary to estimate the peak response-enhancing effect of co-existing pesticides in the calibration solution to obtain accurate results with GC-MS determination. The enhancing effect could be reduced by addition of food matrix to the sample and calibration solutions.

Efficacy and safety of endoscopic submucosal dissection under general anesthesia.

AIM: To evaluate the efficacy and safety of endoscopic submucosal dissection (ESD) under general anesthesia. METHODS: From January 2011 to July 2014, 206 consecutive patients had undergone ESD under general anesthesia for neoplasms of the stomach, esophagus, and colorectum were enrolled in this retrospective study. The efficacy and safety of ESD under general anesthesia were assessed. RESULTS: The en bloc resection rate of esophageal, gastric, and colorectal lesions was 100.0%, 98.3%, and 96.1%, respectively. The complication rate of perforation and bleeding were 0.0% and 0.0% in esophageal ESD, 1.7% and 1.7% in gastric ESD, and 3.9% and 2.0% in colorectal ESD, respectively. No cases of aspiration pneumonia were observed. All complications were managed by conservative treatment, with no surgical intervention required. CONCLUSION: With the cooperation of an anesthesiologist, ESD under general anesthesia appears to be a useful method, decreasing the risk of complications.

Long-term outcome of peroral endoscopic myotomy for achalasia treatment in a 9-year-old female patient.

Achalasia is a primary motility disorder with incomplete lower esophageal sphincter relaxation; it has an annual incidence of 0.11 cases per 100 000 children. Peroral endoscopic myotomy (POEM) is a new endoscopic treatment method for achalasia. Reports about POEM in pediatric patients are rare. We herein report the case of a 9-year-old female patient with achalasia who underwent POEM. The patient underwent endoscopic balloon dilatation because medication was not effective at a previous hospital; however, endoscopic balloon dilatation was not effective either. She then underwent successful POEM upon admission at our hospital. The patient was symptom-free at 2 years postoperatively with no signs of esophagitis in the absence of proton-pump inhibitor therapy.

Peroral endoscopic myotomy for esophageal achalasia: outcomes of the first over 100 patients with short-term follow-up.

BACKGROUND: POEM is a recently developed achalasia treatment method, which combines the efficacy of surgical myotomy with the benefits of endoscopic procedures. Very few studies have focussed on the efficacy and usefulness of POEM in over 100 cases. METHODS: The first 100 adult patients treated according to standard POEM technique in a single center and followed up for 3 months were identified and included in this study (men 42; women 58; mean age 48.2 ± 18.8; range 9-91 years) The pre- and postoperative assessments included Eckardt scores, manometry, endoscopy, and monitoring pH. RESULTS: Mean operative time was 150.8 ± 49.3 min (75-370 min). Adverse events over Grade IIIb by the Clavien-Dindo classification were not encountered. The mean preoperative and postoperative lower esophageal sphincter pressures were 43.6 ± 26.2 and 20.9 ± 12.7 mmHg, respectively, indicating a statistically significant decrease after POEM (P < 0.05). The mean preoperative and postoperative integrated relaxation pressure values were 33.5 ± 15.2 and 15.3 ± 6.5 mmHg (P < 0.05). Furthermore, the Eckardt score significantly decreased from 5.9 ± 2.5 preoperatively to 0.8 ± 0.9 postoperatively (P < 0.05). Clinical success was documented in 99 % of the patients. Short-term outcomes after POEM were extremely good and independent of the age, type of achalasia, and previous treatment method. The percent of monitoring time with a pH < 4 was 25.6 % (22/86) in patients not on proton-pump inhibitors. Nine patients were diagnosed with symptomatic gastroesophageal reflux disease (GERD); patients with reflux esophagitis and symptomatic GERD improved with PPI treatment. CONCLUSIONS: Our results confirm the efficacy of POEM in a large patient series and support POEM as one of the first-line achalasia therapies in the near future.

Drain selection reduces pancreatic fistulae risk: a propensity-score matched study.

BACKGROUND/AIMS: Appropriate drainage management after pancreaticoduodenectomy (PD) is important to prevent and manage serious complications. This prospective study evaluated postoperative complications with either closed or open drainage placement after PD. METHODOLOGY: The incidence of postoperative complications in patients of PD, assigned to 2 groups of closed- and open-drain systems based on assessment periods, were investigated using propensity scores matching (PSM) after accounting for potential covariates. RESULTS: Baseline characteristics were comparable in both groups of patients [n = 100; open, 36; closed, 64). Pancreatic fistulae requiring clinical treatment, and wound infection, were found in 33.3% and 15.6%, and 22.2% and 0%, of patients in open- and closed-drainage groups, respectively. Drainage fluid culture showed exogenous infection (63.6% of bacteria) in the open-drain group which was absent in the closed-drainage group. PSM cohorts had 26 patients in either group. Following PSM, pancreatic fistulae requiring treatment were found in 12/26 (46.2%) and 3/26 (11.5%) of patients in the open- and closed-drain groups (RR, 0.25, 95% CI, 0.08-0.81), respectively. Intra-abdominal abscess (5/26 [19.2%]) and wound infection (7/26 [26.9%]) were found in the open-drain group only. CONCLUSION: These results indicate postoperative retrograde infections may be prevented, and the incidence of pancreatic fistula reduced, with a closed drainage system.