1.Improving prediction of ypT0–1N0 response in rectal cancer: the added value of gross tumor type to magnetic resonance tumor regression grade after chemoradiotherapy in a retrospective cohort study
Kyong-Min KANG ; Mi-Jeong CHOI ; Hong-min AHN ; Heung-Kwon OH ; Duck-Woo KIM ; Jungheum CHO ; Won CHANG ; Young Hoon KIM ; Kyoung Ho LEE ; Yu Kyung JUN ; Yonghoon CHOI ; Sung-Bum KANG
Annals of Surgical Treatment and Research 2026;110(4):237-245
Purpose:
While MRI-based tumor regression grade (mrTRG) has shown promise in evaluating pathologic response to concurrent chemoradiotherapy (CCRT) in rectal cancer, its ability to predict pathologic complete response remains limited.This study aimed to enhance mrTRG’s diagnostic performance in predicting ypT0–1N0 status, a key factor in considering non-radical management after CCRT for locally advanced rectal cancer (LARC).
Methods:
This retrospective study included 430 patients with LARC who underwent radical resection following CCRT at a single referral hospital between April 2018 and September 2024. Multivariable logistic regression was used to identify predictive factors associated with achieving ypT0–1N0 status. The diagnostic performances of mrTRG1–2 alone and in combination with other factors were assessed by comparing sensitivity, specificity, positive-predictive value (PPV), negative-predictive value, and area under the curve (AUC).
Results:
Ninety-three patients (21.6%) achieved ypT0–1N0. In the multivariable analysis, fungating type, cT1–2, and mrTRG1–2 were independent predictors for ypT0–1N0. Integrating mrTRG with gross tumor type yielded the highest AUC of 0.689 among the combined models. For predicting ypT0–1N0, the combination of mrTRG and gross tumor type improved PPV (79.2% vs. 41.5% for mrTRG alone) while also demonstrating enhanced sensitivity compared with ycT0–1N0, the conventional MRI-based predictor (40.9% vs. 22.6%).
Conclusion
This study demonstrated that combining mrTRG and gross tumor type improved the PPV of mrTRG in predicting ypT0–1N0 after CCRT in LARC. Further studies are warranted to validate the role of gross tumor type in refining predictive systems for selecting candidates for non-radical treatment.
2.Single port–assisted diverting ileostomy formation for anastomotic leakage after low anterior resection
Kyong-Min KANG ; Heung-Kwon OH ; Hong-min AHN ; Hye-Rim SHIN ; Min-Hyeong JO ; Mi-Jeong CHOI ; Duck-Woo KIM ; Sung-Bum KANG
Journal of Minimally Invasive Surgery 2025;28(1):47-49
Stoma formation for fecal diversion is a common procedure in patients with various complicated conditions after colorectal surgery, such as anastomotic leakage. The singleincision laparoscopic approach for stoma creation offers several advantages, including a reduction in surgical wounds and related complications as well as optimal visualization of the surgical field. This video demonstrates a single-port–assisted diverting ileostomy in a 61-yearold man with anastomotic leakage following low anterior resection for advanced rectal cancer.
3.Single port–assisted diverting ileostomy formation for anastomotic leakage after low anterior resection
Kyong-Min KANG ; Heung-Kwon OH ; Hong-min AHN ; Hye-Rim SHIN ; Min-Hyeong JO ; Mi-Jeong CHOI ; Duck-Woo KIM ; Sung-Bum KANG
Journal of Minimally Invasive Surgery 2025;28(1):47-49
Stoma formation for fecal diversion is a common procedure in patients with various complicated conditions after colorectal surgery, such as anastomotic leakage. The singleincision laparoscopic approach for stoma creation offers several advantages, including a reduction in surgical wounds and related complications as well as optimal visualization of the surgical field. This video demonstrates a single-port–assisted diverting ileostomy in a 61-yearold man with anastomotic leakage following low anterior resection for advanced rectal cancer.
4.Single port–assisted diverting ileostomy formation for anastomotic leakage after low anterior resection
Kyong-Min KANG ; Heung-Kwon OH ; Hong-min AHN ; Hye-Rim SHIN ; Min-Hyeong JO ; Mi-Jeong CHOI ; Duck-Woo KIM ; Sung-Bum KANG
Journal of Minimally Invasive Surgery 2025;28(1):47-49
Stoma formation for fecal diversion is a common procedure in patients with various complicated conditions after colorectal surgery, such as anastomotic leakage. The singleincision laparoscopic approach for stoma creation offers several advantages, including a reduction in surgical wounds and related complications as well as optimal visualization of the surgical field. This video demonstrates a single-port–assisted diverting ileostomy in a 61-yearold man with anastomotic leakage following low anterior resection for advanced rectal cancer.
5.ABO Antibody Titer Testing Harmonization in Korea:A 5-Year Analysis of External Quality Control Data
Han Joo KIM ; Yousun CHUNG ; Sang-Hyun HWANG ; Heung-Bum OH ; Hyungsuk KIM ; Dae-Hyun KO
Annals of Laboratory Medicine 2025;45(3):334-338
Current ABO titration methods lack standardization and harmonization. We analyzed the consistency of ABO antibody titer testing among Korean laboratories and discussed future directions for standardization by analyzing external quality control data collected by the Korean Association of External Quality Assessment Service over 5 yrs (2019–2023). The analysis included the number of participating institutions and methods, as well as the proportion of acceptable results. To compare column agglutination technology (CAT) and tube methods, we created a normalized variable: ([log 2 titer of laboratory test result]–[mean of log 2 titer for the peer group]). The number of participating institutions and methods increased over time. The use of CAT methods expanded, whereas that of tube methods declined. The proportion of acceptable results ranged from 84.0% to 100%, with no significant differences between CAT and tube methods. An F-test revealed no significant variance differences among institutions using these methods. Tube methods demonstrated lower variance in anti-human globulin testing, and room temperature tube methods exhibited lower variance than that of CAT methods. Domestic laboratories demonstrated highquality performance in ABO antibody titer testing, with no significant differences in acceptable result rates or variance across methods. Continuous efforts toward standardization remain essential.
6.Lateral pelvic lymph node dissection based on nodal response to neoadjuvant chemoradiotherapy in mid/low rectal cancer: a retrospective comparative cohort study
Tae-Gyun LEE ; Duck-Woo KIM ; Hong-min AHN ; Hye-Rim SHIN ; Mi Jeong CHOI ; Min Hyeong JO ; Heung-Kwon OH ; Sung-Bum KANG
Annals of Surgical Treatment and Research 2025;108(6):333-344
Purpose:
Total mesorectal excision (TME) without lateral pelvic lymph node (LPN) dissection (LPND) is feasible in patients with mid/low rectal cancer showing a reduction in LPN size to ≤5 mm following neoadjuvant chemoradiotherapy (nCRT).We aimed to evaluate the clinical outcomes of selective LPNDs based on these criteria.
Methods:
Patients with mid/low rectal cancer and LPNs >5 mm before nCRT were included and classified based on nCRT response (post-nCRT LPN size ≤5 mm [responsive] vs. >5 mm [persistent]) and surgical procedure (TME alone vs. TME + LPND). In the responsive group, LPND was selectively performed only if morphologic predictors of LPN metastasis were present. Clinical outcomes were analyzed across subgroups.
Results:
Of 122 patients, 82 were in the responsive group. Within this group, 61 underwent TME alone and 21 underwent TME + LPND. No locoregional recurrence was observed in either subgroup of the responsive group, with similar systemic metastasis rates (13.1% vs. 14.3%, P > 0.99). The TME alone subgroup showed significantly smaller post-nCRT LPN sizes (1.7 ± 2.1 mm vs. 3.9 ± 1.8 mm, P < 0.001) and lower ycN positivity rates (31.1% vs. 71.4%, P = 0.001).
Conclusion
Selective LPND based on post-nCRT LPN size ≤5 mm and the absence of morphologic predictors of metastasis may serve as a feasible option for managing mid/low rectal cancer with enlarged LPNs, thereby optimizing local control and reducing unnecessary surgeries.
7.Cranial-first approach for laparoscopic extended right hemicolectomy
Kyong-Min KANG ; Heung-Kwon OH ; Hong-Min AHN ; Tae-Gyun LEE ; Hye-Rim SHIN ; Mi-Jeong CHOI ; Duck-Woo KIM ; Sung-Bum KANG
Annals of Coloproctology 2024;40(3):282-284
Complete mesocolic excision and central vascular ligation with D3 lymphadenectomy are important surgical principles for improving oncological outcomes in colon cancer. The cranial-first approach is a colonic mobilization–first approach to radical right hemicolectomy, which has several advantages, including early feasibility assessment, safe dissection from surrounding organs, preestablished inferior margin of lymph node dissection, and revelation of the tangible anatomy of the tributaries of the gastrocolic trunk. This video demonstrates the cranial-first approach to radical right hemicolectomy in a 66-year-old man with locally advanced cecal cancer.
8.Accelerated wound healing after topical application of hyaluronic acid cotton to hemorrhoidectomy wounds in a rat model
Jung Wook SUH ; Myoung-Han LEE ; Heung-Kwon OH ; Hyung Kyung KIM ; Dong-Keon KWEON ; Jeehye LEE ; Hong-min AHN ; Duck-Woo KIM ; Sung-Bum KANG
Annals of Surgical Treatment and Research 2024;106(2):85-92
Purpose:
Anal wounds following hemorrhoidectomy can lead to severe pain and postoperative bleeding, impacting patient recovery and quality of life. Hyaluronic acid (HA) stimulates tissue regeneration and wound healing by accelerating cell migration and proliferation. This study aimed to investigate the differences in wound healing rate and completeness of recovery of perianal wounds topically treated with HA-soaked cotton in a murine model.
Methods:
Forty-eight 8-week-old Sprague-Dawley rats with perianal wounds created using a biopsy punch were divided into 2 groups: simple dressing with gauze (control) and topical HA-soaked cotton. A single application of HA-soaked cotton was administered after surgery. Wound healing rate and completeness of recovery were evaluated by measuring the healed area and conducting histological analyses.
Results:
The HA-cotton group exhibited a shorter complete wound healing duration compared to the control group (13.9 days vs. 16.4 days, P = 0.031). Differences in wound healing area between the 2 groups were greatest on postoperative day 2 (51.6% vs. 28.8%, P < 0.001). The HA-cotton group exhibited fewer cases of granulation tissue (2 vs. 5) or redness (0 vs.3) upon complete wound healing. Histologically, the HA-cotton group showed accelerated reepithelialization, rapid shift to lymphocyte-dominant inflammation, enhanced fibroblast proliferation, and increased collagen deposition compared to the control group.
Conclusion
Herein, topical application of HA-soaked cotton on perianal wounds in rats resulted in accelerated wound healing, particularly in the initial stages, and improved completeness of recovery, underscoring the potential of the topical application of HA-soaked cotton on hemorrhoidectomy wounds in human patients to improve wound healing.
9.Comparative analysis of different surgical approaches for recurrent inguinal hernia: a single-center observational study
Mi Jeong CHOI ; Kang-Seok LEE ; Heung-Kwon OH ; Sang-Hoon AHN ; Hong-min AHN ; Hye-Rim SHIN ; Tae-Gyun LEE ; Min Hyeong JO ; Duck-Woo KIM ; Sung-Bum KANG
Annals of Surgical Treatment and Research 2024;106(6):330-336
Purpose:
Managing recurrent inguinal hernias is complex, and choosing the right surgical approach (laparoscopic vs. open) is vital for patient outcomes. This study compared the outcomes of using the same vs. different surgical approaches for initial and subsequent hernia repairs.
Methods:
We retrospectively analyzed patients who underwent recurrent inguinal hernia repair at Seoul National University Bundang Hospital between January 2014 and May 2023. Patients were divided into the “concordant” and “discordant” groups, comprising patients who underwent same and different approaches in both surgeries, respectively. Preoperative baseline characteristics, index surgery data, postoperative outcomes, and recurrence rates were analyzed and compared.
Results:
In total, 131 patients were enrolled; the concordant and discordant groups comprised 31 (open, n = 19; laparoscopic, n = 12) and 100 patients (open to laparoscopic, n = 68; laparoscopic to open, n = 32), respectively. No significant differences were observed in the mean operation time (50.5 ± 21.7 minutes vs. 50.2 ± 20.0 minutes, P = 0.979), complication rates (6.5% vs. 14.0%, P = 0.356), or 36-month cumulative recurrence rates (9.8% vs. 9.8%; P = 0.865). The mean postoperative hospital stay was significantly shorter in the discordant than in the concordant group (1.8 ± 0.7 vs. 1.4 ± 0.6, P = 0.003).
Conclusion
Most recurrent inguinal hernia repairs were performed using the discordant surgical approach. Overall, concordance in the surgical approach did not significantly affect postoperative outcomes. Therefore, the selection of the surgical approach based on the patient’s condition and surgeon’s preference may be advisable.
10.Effect of prophylactic abdominal drainage on postoperative pain in laparoscopic hemicolectomy for colon cancer: a single-center observational study in Korea
Sung Seo HWANG ; Heung-Kwon OH ; Hye-Rim SHIN ; Tae-Gyun LEE ; Mi Jeong CHOI ; Min Hyeong JO ; Hong-min AHN ; Hyeonjeong PARK ; Hyun Hee SIM ; Eunjeong JI ; Anuj Naresh SINGHI ; Duck-Woo KIM ; Sung-Bum KANG
Journal of Minimally Invasive Surgery 2024;27(2):76-84
Purpose:
This study aimed to evaluate the effect of prophylactic abdominal drainage (AD) in laparoscopic hemicolectomy, focusing on assessing postoperative pain outcomes.
Methods:
Patients were categorized into two groups: those with and without AD (AD group vs.no-AD group). A numerical rating scale (NRS) was used to assess postoperative pain on each postoperative day (POD). Further, the inverse probability of treatment weighting (IPTW) method was used to reduce intergroup bias.
Results:
In total, 204 patients who underwent laparoscopic hemicolectomies by a single surgeon between June 2013 and September 2022 at a single institution were retrospectively reviewed. After adjusting for IPTW, NRS scores on POD 2 were significantly lower in the no-AD group (3.2 ± 0.8 vs. 3.4 ± 0.8, p = 0.043). Further examination of postoperative outcomes showed no statistically significant differences in complications between the AD (17.3%) and no-AD (12.4%) groups (p = 0.170). The postoperative length of hospital stay was 7.3 ± 2.8 days in the AD group and 6.9 ± 3.0 days in the no-AD group, with no significant difference (p = 0.298). Time to first flatus was 3.0 ± 0.9 days in the AD group and 2.7 ± 0.9 days in the no-AD group, with no significant difference (p = 0.078). Regarding readmission within 1 month, there were four cases each in the AD (2.3%) and no-AD (1.7%) groups, with no significant difference (p = 0.733).
Conclusion
Laparoscopic hemicolectomy without AD resulted in no significant differences in postoperative clinical outcomes, except for postoperative pain. This finding suggests that prophylactic AD may exacerbate postoperative pain.

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