Background: s/Aims: Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021. Methods: Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop. Results: In November 2021, the finalized draft was presented for public scrutiny during a formal hearing. Conclusions The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Purpose: We prospectively compared the diagnostic accuracy of kidney dynamic computed tomography (KDCT), magnetic resonance imaging (MRI), and contrast-enhanced ultrasonography (CEUS) for the assessment of small renal mass (SRM) (≤4 cm). Materials and Methods: Seventy-six patients with SRM (mean age, 58.4±13.1 years) who underwent renal biopsy (n=11) or nephrectomy (partial or radical) (n=65) were enrolled. All patients underwent KDCT, MRI, and CEUS before renal biopsy or nephrectomy. Results: The mean maximal tumor size was 21.0±9.8 mm. The mean R.E.N.A.L nephrometry score was 7.0±1.7. Fifty-six patients had renal cell carcinoma (RCC) (clear cell, 42; papillary, 7; chromophobe, 5; succinate dehydrogenase deficient, 1; unspecified RCC, 1). Twenty patients had a benign tumor (angiomyolipoma, 11; oncocytoma, 3; others, 6). Clinicopathologic variables were comparable in RCC and benign groups. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of KDCT were 89.3%, 10.0%, 73.5%, and 25.0%, respectively. The sensitivity, specificity, PPV, and NPV of MRI were 89.3%, 10.0%, 73.5%, and 25.0%, respectively. The sensitivity, specificity, PPV, and NPV of CEUS were 85.7%, 50.0%, 82.8%, and 55.6%, respectively. The diagnostic accuracy of KDCT, MRI, and CEUS were 68.4%, 68.4%, and 76.3%, respectively. In a subgroup analysis based on clinical tumor size of 10 mm and 20 mm, CEUS also showed the highest diagnostic accuracy. Conclusions CEUS had the highest specificity, PPV, and NPV and may help improve the assessment of SRM.

Purpose: In this study, polymerase chain reaction (PCR)-based microsatellite instability (MSI) testing was comprehensively analyzed and compared with immunohistochemistry (IHC) for mismatch repair (MMR) protein expression in patients with gastric cancer (GC). Materials and Methods: In 5,676 GC cases, PCR-based MSI testing using five microsatellites (BAT-26, BAT-25, D5S346, D2S123, and D17S250) and IHC for MLH1 were performed. Reevaluation of MSI testing/MLH1 IHC and additional IHC for MSH2, MSH6, and PMS2 were performed in discordant/indeterminate cases. Results: Of the 5,676 cases, microsatellite stable (MSS)/MSI-low and intact MLH1 were observed in 5,082 cases (89.5%), whereas MSI-high (MSI-H) and loss of MLH1 expression were observed in 502 cases (8.8%). We re-evaluated the remaining 92 cases (1.6%) with a discordant/ indeterminate status. Re-evaluation showed 1) 37 concordant cases (0.7%) (18 and 19 cases of MSI-H/MMR-deficient (dMMR) and MSS/MMR-proficient (pMMR), respectively), 2) 6 discordant cases (0.1%) (3 cases each of MSI-H/pMMR and MSS/dMMR), 3) 14 MSI indeterminate cases (0.2%) (1 case of dMMR and 13 cases of pMMR), and 4) 35 IHC indeterminate cases (0.6%) (22 and 13 cases of MSI-H and MSS, respectively). Finally, MSI-H or dMMR was observed in 549 cases (9.7%), of which 47 (0.8%) were additionally confirmed as MSI-H or dMMR by reevaluation. Sensitivity was 99.3% for MSI testing and 95.4% for MMR IHC. Conclusions Considering the low incidence of MSI-H or dMMR, discordant/indeterminate results were occasionally identified in GCs, in which case complementary testing is required.These findings could help improve the accuracy of MSI/MMR testing in daily practice.

Purpose: Resectable pancreatic ductal adenocarcinoma (PDAC) has a high risk of recurrence after curative resection; despite this, the preoperative risk factors for predicting early recurrence remain unclear. This study therefore aimed to identify preoperative inflammation and nutrition factors associated with early recurrence of resectable PDAC. Methods: From March 2021 to November 2021, a total of 20 patients who underwent curative resection for PDAC were enrolled in this study. We evaluated the risk factors for early recurrence within 1 year by univariate and multivariate analyses using Cox hazard proportional regression. The cutoff values for predicting recurrence were examined using receiver operating characteristic (ROC) curves. Results: In our univariate and multivariate analyses, C-reactive protein (CRP), CRP-albumin ratio, and CRP-prealbumin ratio, as well as sex and age, were significant independent prognostic factors for early recurrence in PDAC. However, known inflammatory factors (neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios), nutritional factors (albumin, prealbumin, ferritin, vitamin D), and inflammatory-nutritional factors (Glasgow Prognostic Score, modified Glasgow Prognostic Score, albumin-bilirubin) showed no association with early recurrence. In addition, using cutoff values by ROC curve analysis, a high preoperative CRP level of >5 mg/L, as well as high CRP-to-albumin (>5.3) and CRP-to-prealbumin (>1.3) ratios showed no prognostic value. Conclusion Our results showed that inflammatory and perioperative nutritional factors, especially CRP-to-prealbumin ratio, have significant associations with early recurrence after curative resection in resectable PDAC. Therefore, for such patients, a cautious approach is needed when inflammation and poor nutritional status are present.

Background/Aims: We investigated the factors related to spleen length and the diagnostic accuracy of a model using spleen length corrected by related factors, for the prediction of varices needing treatment (VNT). Methods: Various prediction models for VNT including spleen length were analyzed in the cohort of compensated advanced chronic liver disease (cACLD), defined as liver stiffness (LS) ≥10 kPa in a recent study. The associated factors for spleen length were identified in healthy subjects to improve the prediction of VNT. Results: Among 1,218 cACLD patients, VNT was noted in 249 patients (20.4%). On multivariate analysis, longer spleen length, lower platelet count, and higher LS value were independent predictors for VNT (all p<0.001). In multivariate analysis of 1,041 healthy subjects, age (β=–0.027), sex (β=0.762), and body mass index (β=0.097) were found to be significant factors for spleen length (all p<0.001). Using the β values, the estimated spleen length was calculated. To improve the prediction of VNT, the ratio of measured and estimated spleen length was calculated. Based on binary regression analysis results, the LS value-spleen ratio to platelet score (LSRPS) was calcu-lated as follows: 0.027×LS value (kPa)+2.690×measured/estimated spleen ratio–0.011×platelet count (cells×10 9 /L)–4.215. The area under the receiver operating characteristic of the LSRPS for VNT was 0.820, which was significantly higher than 0.797 of LS value-spleen diameter to plateletratio score (LSPS) (p=0.006). Conclusions Spleen length is influenced by age, sex, and body mass index in the Asian population. The LSRPS using the measured/estimated spleen ratio had higher diagnostic accuracy than LSPS in predicting VNT in patients with cACLD.

Purpose: Pancreatic enzyme reflux into the biliary tract is associated with chronic inflammation and increased cellular proliferation in the biliary epithelium, leading to biliary carcinoma. We evaluated the relationship between high bile juice amylase levels and biliary microflora in patients with malignant gallbladder lesions. Methods: In this retrospective study, 25 gallbladder specimens were obtained from patients with gallbladder cancer to evaluate amylase levels and perform bacterial culture. The samples were divided into high and low amylase groups and culture-positive and negative groups for analysis. Bile juice amylase 3 times higher than the normal serum amylase level (36–128 IU/L) was considered high. Results: The number of positive cultures was higher in the high amylase group than in the low amylase group, but the difference was insignificant. There were no differences in other clinicopathological factors. Sixteen patients showed positive culture results; Escherichia coli and Klebsiella spp. were the most common gram-negative bacteria, whereas Enterococcus and Streptococcus spp. were the most common gram-positive bacteria. Age and bile juice amylase levels were significantly higher in the culture-positive group than in the culture-negative group. The incidence of bacterial resistance to cephalosporins was 6.25%–35.29%, and this incidence was particularly high for lower-generation cephalosporins. Conclusion Bacteria in gallbladder were identified more frequently when the amylase level was high. High amylase levels in the gallbladder can be associated with caused chronic bacterial infections with occult pancreaticobiliary reflux, potentially triggering gallbladder cancer

Background: Cleft lip and cleft palate are the most frequent congenital craniofacial deformities, with an incidence of approximately 1 per 700 people. Postoperative palatal fistula is one of the most significant long-term complications. This study investigated the incidence of postoperative palatal fistula and its predictive factors based on 25 years of experience at our hospital. Methods: We retrospectively reviewed 636 consecutive palatal repairs performed between January 1996 and October 2020 by a single surgeon. Data from patients’ medical records regarding cleft palate repair were analyzed. The preoperative extent of the cleft was evaluated using the Veau classification system, and the cleft palate repair technique was chosen according to the extent of the cleft. SPSS version 25.0 was used for all statistical analyses, and exploratory univariate associations were investigated using the t-test. Results: Fistulas occurred in 20 of the 636 patients; thus, the incidence of palatal fistula was 3.1%. The most common fistula location was the hard palate (9/20, 45%), followed by the junction of the hard and soft palate (6/20, 30%) and the soft palate (5/20, 25%). The cleft palate repair technique significantly predicted the incidence of palatal fistula following cleft palate repair (P=0.042). Fistula incidence was significantly higher in patients who underwent surgery using the Furlow double-opposing Z-plasty technique (12.1%) than in cases where the Busan modification (3.0%) or two-flap technique (2.0%) was used. Conclusions The overall incidence of palatal fistulas was 3.1% in this study. Moreover, the technique of cleft palate repair predicted fistula incidence.

Objective: We present how to perform radiofrequency sensory stimulation (RFSS) and whether RFSS could be helpful in identifying symptomatic injured roots in multilevel lumbar stenosis. Methods: Consecutive patients who underwent RFSS from 2010 to 2012 were enrolled. To identify pathologic lesions, RFSS was performed for suspicious roots, as determined using lumbar magnetic resonance imaging (MRI). The RFSS procedure resembled transforaminal root block. During RFSS of the suspicious root, patients could indicate whether stimulation induced their usual pain and/or sensory changes and could indicate whether the same leg area was affected. The number of possible symptomatic roots on MRI was evaluated before and after RFSS. Based on the RFSS results, we confirmed the presence of symptomatic nerve root(s) and performed surgical decompression. Surgical results, such as numeric rating scale (NRS) scores for low back pain (LBP) and leg pain (LP), and Oswestry disability index (ODI), were evaluated. Results: Ten patients were enrolled in the study. Their mean age was 70.1±9.7 years. Clinically, NRS-LBP, NRS-LP, and ODI before surgery were 5.1%, 7.5%, and 53.2%, respectively. The mean number of suspicious roots was 2.6±0.8. After RFSS, the mean number of symptomatic roots was 1.6±1.0. On average, 1.4 lumbar segments were decompressed. The follow-up period was 35.3±12.8 months. At the last follow-up, NRS-LBP, NRS-LP, and ODI were 3.1%, 1.5%, and 35.3%, respectively. There was no recurrence or need for further surgical treatment for lumbar stenosis. Conclusion RFSS is a potentially helpful diagnostic tool for verifying and localizing symptomatic injured root lesions, particularly in patients with multilevel spinal stenosis.