1.Predictors and patterns of early liver regeneration after major hepatectomy
Seoyeong KU ; Garam LEE ; Hyung Hwan MOON ; Hyungjune KU ; Won Jong YANG ; Junho SONG ; Suyeon KIM ; Chol Min KANG ; Amy CHOI ; Dong Hyeon GIM ; Young Il CHOI ; Dong Hoon SHIN ; Namkee OH ; Jinsoo RHU
Kosin Medical Journal 2026;41(1):58-66
Background:
Postoperative liver regeneration is essential for maintaining hepatic function. This study evaluated the rate, determinants, and volumetric patterns of early liver regeneration after hemihepatectomy.
Methods:
A retrospective review was conducted of 50 patients who underwent right or left hemihepatectomy between April 2019 and March 2025. Liver and spleen volumes (SV) were assessed preoperatively, at postoperative day (POD) 1 week, and at POD 3 months. Early liver regeneration rate (LRR) was defined as the percentage increase in remnant liver volume at POD 1 week relative to the preoperative future liver remnant (FLR), and patients were categorized into low (<50%) and high (≥50%) LRR groups. Clinical, biochemical, and volumetric variables were compared, and predictors of regeneration were identified using multivariable analyses. Regeneration patterns were also examined according to whether the FLR/standard liver volume (SLV) ratio was <50% or ≥50%.
Results:
FLR/SLV was the strongest independent predictor of rapid early liver regeneration (p<0.001). Remnants with FLR/SLV <50% exhibited rapid and sustained regeneration, whereas those with FLR/SLV ≥50% showed slower regrowth that plateaued after reaching approximately 90% of SLV. SV increased at POD 1 week in all patients; however, only the FLR/SLV ≥50% group showed a reduction by POD 3 months, whereas the <50% group maintained elevated volumes.
Conclusions
FLR/SLV reliably predicts early postoperative liver regeneration. Smaller remnants regenerate more rapidly, whereas persistent splenic enlargement suggests a sustained portal hemodynamic burden. Combined evaluation of FLR/SLV and SV may enhance perioperative risk assessment and surgical planning.
2.Artificial intelligence-assisted prediction of bile duct bifurcation site in pure laparoscopic donor right hepatectomy: a retrospective feasibility study
Jiyoung BAIK ; Namkee OH ; Gyu-Seong CHOI ; Jinsoo RHU ; Jongman KIM
Annals of Surgical Treatment and Research 2026;110(6):359-365
Purpose:
Accurate identification of the bile duct bifurcation site is crucial in pure laparoscopic donor right hepatectomy (PLDRH) for living donor liver transplantation. This study aimed to develop and evaluate a deep learning model to predict the bile duct bifurcation site for surgical precision.
Methods:
We retrospectively analyzed 55 PLDRH procedures conducted between August 2021 and April 2022. A deep learning model combining UNet with a MiT-B3 encoder was trained on 150 manually annotated frames. We then incorporated expert-reviewed pseudo-labels from an additional 901 frames to refine the model. Performance was evaluated using 5-fold cross-validation and an independent test set.
Results:
Clinical evaluation showed a 97% accuracy in 5-fold cross-validation and 93.3% accuracy in the independent test set. From the initial to final model, dice similarity coefficient improved from 0.392 to 0.472, intersection over union from 0.279 to 0.339, and sensitivity from 0.487 to 0.643, while specificity remained consistent at 0.993.
Conclusion
The proposed artificial intelligence (AI) model demonstrated strong clinical performance in predicting the bile duct bifurcation site during PLDRH. Despite modest quantitative scores, the high clinical accuracy highlights the potential of integrating AI for precise donor hepatectomy.
3.Physical AI goes to the operating room: are we ready for the Surgical Data Factory?
Namkee OH ; Kyu-Hwan JUNG ; Gyu-Seong CHOI
Annals of Surgical Treatment and Research 2026;110(3):135-143
The operating room remains a paradox: it is one of the most sensor-rich environments in the hospital, yet it produces largely underutilized data. While surgical artificial intelligence (AI) has achieved remarkable progress in recent years, the day-to-day practice of surgery has changed little, with most systems confined to passive decision support. This narrative review traces the evolution of surgical AI from perception to cognition to early forms of action, arguing that the next paradigm shift requires “physical AI”—systems capable of meaningful physical interaction and autonomous execution. The clinical motivation for pursuing physical AI is clear: surgical outcomes vary substantially across surgeons, access is constrained by workforce shortages, and high-quality care remains tied to the scarcity of human expertise. If reliable autonomous systems can be developed, surgery could become more standardized, scalable, and reproducible.However, a critical bottleneck persists: the scarcity of synchronized, multimodal training data. The fundamental barrier is environmental rather than algorithmic, as most operating rooms are not configured to measure surgical practice objectively. We propose reconceptualizing the operating room as a “Surgical Data Factory”—a closed-loop ecosystem designed to capture multimodal signals, structure them via consensus taxonomies linked to outcomes, and utilize them for training, validation, and monitoring. Surgeons must transition from passive users to active architects of this infrastructure.Investing in systematic data governance is the prerequisite for responsibly developing, validating, and scaling physical AI in surgery.
4.Impact of low tacrolimus level on graft rejection, survival, and hepatocellular carcinoma recurrence
Hayeon DO ; Namkee OH ; Jiyoung BAIK ; Suk Min GWON ; Youngju RYU ; Eunjin LEE ; Sunghyo AN ; Jinsoo RHU ; Gyu-Seong CHOI ; Jae-Won JOH ; Jongman KIM
Annals of Liver Transplantation 2025;5(2):124-133
Background:
Tacrolimus is a key immunosuppressant after liver transplantation.Although guideline-recommended trough levels are 4–10 ng/mL, concerns about nephrotoxicity, metabolic complications, and malignancies have led to interest in minimizing tacrolimus use. However, the effects of lower tacrolimus levels on graft rejection and hepatocellular carcinoma (HCC) recurrence remain unclear.
Methods:
We conducted a single-center, retrospective study of adult patients (≥19 years) who underwent living donor liver transplantation between January 2000 and December 2021. Patients were divided into low tacrolimus (FK) (<6 ng/mL) and high FK (≥6 ng/mL) groups based on tacrolimus levels measured 1–2 years post-transplantation. We analyzed overall survival, biopsy-proven rejection-free survival, and HCC recurrence-free survival in relevant subgroups. Cox proportional hazards regression identified predictors of mortality, rejection, and HCC recurrence.
Results:
Among 1,117 recipients, 941 were in the low FK group and 176 in the high FK group. Landmark analysis showed significantly better 10-year overall survival in the low FK group (82.8% vs. 68.8%, p=0.016), while rejection-free survival did not differ significantly beyond 2 years (p=0.098), despite early separation favoring the low FK group (p<0.001). Higher tacrolimus levels independently predicted increased mortality (hazard ratio [HR]=1.98, 95% confidence interval [CI] 1.35–2.89; p<0.001) and rejection (HR=2.20, 95% CI 1.48–3.27; p<0.001). Among 614 HCC patients, landmark analysis revealed no significant difference in recurrence-free survival (77.7% vs. 81.2%, p=0.288) or overall survival (77.3% vs. 65.8%, p=0.215), and FK levels were not independently associated with either outcome.
Conclusion
Maintaining tacrolimus levels below 6 ng/mL was associated with better survival and rejection outcomes without increasing HCC recurrence, suggesting dose minimization may be feasible in selected patients.
5.Left lobe living donor liver transplantation using the resection and partial liver segment 2–3 transplantation with delayed total hepatectomy (RAPID) procedure in cirrhotic patients:First case report in Korea
Jongman KIM ; Jinsoo RHU ; Eunjin LEE ; Youngju RYU ; Sunghyo AN ; Sung Jun JO ; Namkee OH ; Seungwook HAN ; Sunghae PARK ; Gyu-Seong CHOI
Annals of Hepato-Biliary-Pancreatic Surgery 2024;28(3):388-392
In liver transplantation, the primary concern is to ensure an adequate future liver remnant (FLR) volume for the donor, while selecting a graft of sufficient size for the recipient. The living donor–resection and partial liver segment 2−3 transplantation with delayed total hepatectomy (LD−RAPID) procedure offers a potential solution to expand the donor pool for living donor liver transplantation (LDLT).We report the first case involving a cirrhotic patient with autoimmune hepatitis and hepatocellular carcinoma, who underwent left lobe LDLT using the LD−RAPID procedure. The living liver donor (LLD) underwent a laparoscopic left hepatectomy, including middle hepatic vein. The resection on the recipient side was an extended left hepatectomy, including the middle hepatic vein orifice and caudate lobe. At postoperative day 7, a computed tomography scan showed hypertrophy of the left graft from 320 g to 465 mL (i.e., a 45.3% increase in graft volume body weight ratio from 0.60% to 0.77%). After a 7-day interval, the diseased right lobe was removed in the second stage surgery. The LD−RAPID procedure using left lobe graft allows for the use of a small liver graft or small FLR volume in LLD in LDLT, which expands the donor pool to minimize the risk to LLD by enabling the donation of a smaller liver portion.
6.ChatGPT Predicts In-Hospital All-Cause Mortality for Sepsis: In-Context Learning with the Korean Sepsis Alliance Database
Namkee OH ; Won Chul CHA ; Jun Hyuk SEO ; Seong-Gyu CHOI ; Jong Man KIM ; Chi Ryang CHUNG ; Gee Young SUH ; Su Yeon LEE ; Dong Kyu OH ; Mi Hyeon PARK ; Chae-Man LIM ; Ryoung-Eun KO ;
Healthcare Informatics Research 2024;30(3):266-276
Objectives:
Sepsis is a leading global cause of mortality, and predicting its outcomes is vital for improving patient care. This study explored the capabilities of ChatGPT, a state-of-the-art natural language processing model, in predicting in-hospital mortality for sepsis patients.
Methods:
This study utilized data from the Korean Sepsis Alliance (KSA) database, collected between 2019 and 2021, focusing on adult intensive care unit (ICU) patients and aiming to determine whether ChatGPT could predict all-cause mortality after ICU admission at 7 and 30 days. Structured prompts enabled ChatGPT to engage in in-context learning, with the number of patient examples varying from zero to six. The predictive capabilities of ChatGPT-3.5-turbo and ChatGPT-4 were then compared against a gradient boosting model (GBM) using various performance metrics.
Results:
From the KSA database, 4,786 patients formed the 7-day mortality prediction dataset, of whom 718 died, and 4,025 patients formed the 30-day dataset, with 1,368 deaths. Age and clinical markers (e.g., Sequential Organ Failure Assessment score and lactic acid levels) showed significant differences between survivors and non-survivors in both datasets. For 7-day mortality predictions, the area under the receiver operating characteristic curve (AUROC) was 0.70–0.83 for GPT-4, 0.51–0.70 for GPT-3.5, and 0.79 for GBM. The AUROC for 30-day mortality was 0.51–0.59 for GPT-4, 0.47–0.57 for GPT-3.5, and 0.76 for GBM. Zero-shot predictions using GPT-4 for mortality from ICU admission to day 30 showed AUROCs from the mid-0.60s to 0.75 for GPT-4 and mainly from 0.47 to 0.63 for GPT-3.5.
Conclusions
GPT-4 demonstrated potential in predicting short-term in-hospital mortality, although its performance varied across different evaluation metrics.
7.Deceased donor liver transplantation for post-hepatectomy liver failure with fixed pupils
Sunghyo AN ; Jongman KIM ; Sungjun JO ; Namkee OH ; Eunmi GIL ; Gaabsoo KIM
Annals of Liver Transplantation 2024;4(2):112-116
Deceased donor liver transplantation (DDLT) raises ethical and social questions about liver transplantation for patients who are not expected to live. Patients with post-hepatectomy liver failure must have DDLT as soon as possible. Here, we detail a particular dilemma that the transplant team had while deciding whether to harvest liver from a deceased donor in the face of the recipient’s non-reactive, fully dilated pupils while they awaited a liver transplant in the intensive care unit. Despite having fixed dilated pupils during the neurologic evaluation, the patient eventually had effective DDLT, indicating that DDLT should not be done unless there is obvious brain death.
8.Two cases of living donor liver transplantation for colorectal liver metastases in Korea
Abdullah ALSHAMRANI ; Eunjin LEE ; Youngju RHU ; Sunghyo AN ; Sungjun JO ; Namkee OH ; Jinsoo RHU ; Jongman KIM
Annals of Liver Transplantation 2024;4(2):129-133
Colorectal cancer (CRC) poses a significant global health challenge, particularly with patients often experiencing liver metastases. Surgical resection remains the standard treatment; however, many patients face ineligibility due to disease status, contributing to poor prognoses. Liver transplantation (LT) is a viable alternative for select patients with advanced disease. This case report details the clinical outcomes of two CRC patients with multiple liver metastases who successfully underwent living donor LT (LDLT). Both individuals had intricate medical histories and pre-existing liver issues. Patient 1, a 58-year-old male, received extensive pre-transplant interventions, including multiple radiofrequency ablations and pulmonary resections. Patient 2, a 50-year-old male, had cirrhosis alongside colorectal cancer with liver metastases and completed chemotherapy. The cases illustrate LDLT's viability and potential advantages for complex CRC cases with liver metastases. The patients’ intricate medical backgrounds necessitate thorough pre-transplant evaluations and vigilant post-transplant supervision. Moreover, these cases highlight the critical nature of ongoing follow-up for evaluating long-term survival and recognizing possible complications.
9.Successful living liver donation from a septuagenarian donor with cardiac diseases
Jiyoung BAIK ; Jongman KIM ; Eunjin LEE ; Sunghyo AN ; Namkee OH ; Eunmi GIL ; Gaabsoo KIM
Annals of Liver Transplantation 2024;4(2):124-128
We present the case of a 74-year-old female who had a right hepatectomy performed laparoscopically to donate her liver to her a 40-year-old son who had alcoholic liver cirrhosis. She voluntarily cooperated, and thorough medical and psychological evaluations were carried out. The receiver underwent surgery in 296 minutes, while the donor took 158 minutes. With normal liver function, the donor and recipient were released from the hospital on days 10 and 14, respectively, after a smooth recovery. Three months following the living donor liver transplant, both the receiver and the living liver donor have not experienced any problems and are doing well.
10.Outcomes of living donor liver transplantation in patients with concurrent extrahepatic malignancy
John Hee PARK ; Jongman KIM ; Sunghyo AN ; Namkee OH ; Jinsoo RHU ; Gyu-Seong CHOI ; Jae-Won JOH
Annals of Liver Transplantation 2024;4(2):102-107
Background:
Concurrently extrahepatic malignancy (EHM) has long been considered a relative contraindication to liver transplantation because of cancer recurrence. However, we were frequently challenged as living donor liver transplantation (LDLT) may be the only life-saving option available in the setting of end-stage liver disease, or hepatocellular carcinoma (HCC) with concurrent EHM. In this study, we aim to analyze the outcome of adult LDLT with concurrent EHM at the time of LDLT.
Methods:
Of 2,448 adults who underwent LDLT from May 1996 to January 2023 at our institution, we retrospectively analyzed data for 16 patients with an EHM treated within 6 months at the time of LDLT.
Results:
Among 16 patients, one patient died of postoperative liver failure, and another died 3 months post-surgery due to bowel perforation. The cumulative overall survival rates at 1-year, 3-year, and 5-year were 87.5%, 78.8%, and 68.9%, respectively. Five patients died during follow-up; only one patient died due to a cancer-related cause. None of the eight patients with low-risk EHM showed EHM recurrence after LDLT. EHM recurrence occurred in one patient with intermediate risk, and cancer progression was seen in one patient with high-risk EHM. Concurrent HCC was present in six patients, and HCC recurrence occurred in two (33.33%). There was no statistically significant difference in survival between patients with hematologic (n=5) and non-hematologic (n=11) EHM (p=0.891).
Conclusion
Our study shows a high survival rate for LDLT in patients with concurrently EHM. Hence, we suggest that concurrent EHM should not be a contraindication to LDLT even when ‘minimum remission times’ have not yet elapsed.

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