Making research more sustainable doesn’t happen overnight. For months, our team at Experimental Surgery has been taking a close look at how we work: how much energy our equipment uses, what we order and how, what ends up in the bin, and which habits we could change along the way.

That effort has now paid off. My Green Lab is an international certification programme that assesses labs across areas like energy, water, waste, chemicals, materials and staff involvement. Out of five possible tiers, we reached Platinum, the second-highest level.

Our heartfelt thanks go to Kirsten Führer, Anja Schirmeier, Anja Reutzel Selke, Marion Marksteiner and Steffen Lippert, who drove this process forward with incredible dedication. And to every colleague who questioned old routines, shared suggestions and made small changes in daily lab work: this result belongs to all of you.

We see this certification as a milestone, not a finish line. There’s still plenty to improve, and we’re looking forward to the next steps.

Prof. Dr. med. Nathanael Raschzok and his research group have received a funding commitment of €990,264 from German Cancer Aid (Deutsche Krebshilfe). The GTO-001 trial (German Transplant Oncology Study 001; NCT07811453) aims to establish liver transplantation as a treatment option in Germany for carefully selected patients with unresectable colorectal liver metastases.

Colorectal cancer is one of the leading causes of cancer-related death worldwide; about half of all patients develop metastases, most often in the liver. Surgical removal is the only potentially curative treatment, but only 20 to 40 percent of patients are eligible. If the metastases can be treated neither surgically nor by interventional procedures, palliative chemotherapy remains the only option, with a 5-year survival rate of around 10 percent.
In 2024, the randomized European TransMet trial led by Prof. René Adam (Paris) showed in The Lancet that selected patients benefit substantially from liver transplantation: five years after transplantation plus chemotherapy, 73 percent of participants were alive, compared with 9 percent on chemotherapy alone. In Germany, liver transplantation for this indication is currently possible only within clinical trials.

Rigorous patient selection by a National Tumor Board.
GTO-001 is a prospective, non-randomized interventional trial planned at up to 19 centers in Germany. Eligible patients are aged 18 to 65 years, have had their primary tumor removed, show no disease outside the liver, and have liver metastases that have remained stable for at least six months under chemotherapy. Every case is reviewed centrally by the “National Tumor Board for Transplant Oncology”, established specifically for the trial, in which experienced surgeons, radiologists and oncologists meet by videoconference. The board approves listing only if resection or ablation has been ruled out and all study criteria are met.
The protocol builds on the TransMet trial, the Toronto protocol and the consensus guidelines of the International Hepato-Pancreato-Biliary Association; in addition, the metabolic tumor volume measured by PET imaging serves as a selection criterion. Grafts come either from deceased donors allocated via Eurotransplant or from living donors. Immediately before transplantation, surgical exploration rules out tumor spread beyond the liver.

Endpoints and outlook
The primary endpoint is 5-year survival after liver transplantation: the trial aims to show that more than half of the transplanted patients are alive after five years. Because only a small proportion of patients meet all criteria up to transplantation, around 260 patients will be assessed in order to reach 26 transplantations. Secondary endpoints include overall and recurrence-free survival, graft survival and postoperative complications; exploratory analyses address risk scores and circulating tumor DNA.
If successful, the trial could provide the evidence base for including liver transplantation for unresectable colorectal liver metastases in the German guidelines for organ transplantation. Given the shortage of donor organs, it is essential that grafts are used where long-term benefit can be expected. At the same time, risks remain – including tumor recurrence under immunosuppression.

Prof. Raschzok is the overall study lead, and PD Dr. med. Simon Moosburner, MHBA and Fellow of the BIH Charité Clinician Scientist Programm, serves as Coordinating Investigator. The trial is overseen by an international Data Safety Monitoring Board (Dr. Elena Elez, Barcelona; Prof. Chiara Cremolini, Pisa; Prof. Pål-Dag Line, Oslo; Dr. Gonzalo Sapisochin, Toronto), an Advisory Board led by Prof. René Adam (Paris), and a Steering Committee comprising Prof. Igor M. Sauer, Prof. Johann Pratschke and Prof. Dominik P. Modest (Charité). The patient organization Lebertransplantierte Deutschland e. V. contributed to the study design; the trial is independent of industry. The ethics application is in preparation, and the trial is scheduled to start in April 2027.

"Nicotinamide Adenine Dinucleotide as a Potential Biomarker for Graft Viability During Normothermic Machine Perfusion: An Ex Vivo Rodent Study" by K.A. Walter, L. Boerger, A. Pietsch, L. Gilles, P. Brunnbauer, C. Kamali, K.H. Hillebrandt, J. Iske, J. Pratschke, I.M Sauer, N. Raschzok, F. Krenzien, and S. Moosburner is available in Artificial Organs. 2026 Oct;50(10):1384-1395.

The shortage of donor organs has increased the use of extended criteria donor (ECD) grafts in liver transplantation. Normothermic machine perfusion (NMP) could be used as a platform for real-time quality assessment, which is crucial since ECD grafts are more susceptible to ischemia-reperfusion injury (IRI). As nicotinamide adenine dinucleotide (NAD+) is a central mediator of cellular antioxidativedefense, reduced intracellular NAD (iNAD+) levels in grafts sustaining greater injury may reflect diminished antioxidative capacity and could serve as a marker to assess graft quality. This study aimed to investigate iNAD+ in comparison to existing damage-associated parameters for liver graft quality in a small animal NMP model simulating ECD conditions through advanced donor age, prolonged cold ischemia time (CIT), and donation after circulatory death (DCD).

Fifty-nine male Sprague-Dawley rat livers were analyzed across six experimental groups defined by donor age (3 months [young] or 12 months [elderly]), procurement modality (standard procurement or donation after circulatory death [DCD]), and cold ischemia time (CIT; 6 h or 12 h), followed by 6 h of NMP. No livers were excluded from analysis. iNAD+ levels were quantified using a colorimetric enzymatic assay.

Perfusate iNAD+ levels continuously rose over time during NMP and differed significantly between intervention groups (p = 0.003). iNAD+ correlated negatively with ALT levels (R = -0.36, p = 0.024) and liver tissue necrosis in grafts (perfusate R = -0.24, p = 0.17; tissue R = -0.19, p = 0.2), although these associations did not reach statistical significance. Long CIT, higher donor age, and DCD procurement were associated with lower iNAD+ levels. iNAD+ did not correlate with lactate clearance or bile production (both p > 0.05). A non-significant trend toward a positive association between iNAD+ and glucose metabolism was observed (R = 0.29, p = 0.077).

Higher perfusate iNAD+ levels were associated with better organ performance, consistent with iNAD+ reflecting the graft's antioxidative metabolic capacity. Lower iNAD+ levels in elderly and DCD grafts aligned with established damage markers. Perfusate iNAD+ may therefore offer a complementary tool for evaluating metabolic activity and organ performance during NMP, pending prospective validation.

"Effect of virtual reality on spatial–anatomical understanding in preoperative liver surgery: a randomized crossover study" by A. Zolkin, Ch. Rüger, Ch. Remde, Z. Akbal, M.M. Maurer, N. Raschzok, J. Pratschke, I.M. Sauer, and M. Queisner is available in Scientific Reports volume 16, Article number: 21191 (2026) d.

The study "Proteomic profiling of colorectal liver metastases reveals histopathological response-specific molecular signatures of chemotherapy efficacy" explores proteomic differences in colorectal liver metastases (CRLM) to understand chemoresistance and identify potential biomarkers for treatment response.

33 tissue samples from 31 patients were analyzed, including patients treated preoperatively with platinum-based chemotherapy, non-platinum-based chemotherapy, or targeted therapies, as well as untreated patients. Tumors were classified into major (MR), partial (PR), or no response (NR) groups using histopathological criteria. Proteomic profiling was performed using label-free mass spectrometry (LFQ-MS).
Analysis identified 607 proteins with differential expression across response types. Responsive CRLM were enriched in pathways related to immune infiltration, extracellular matrix organization, complement activation, and apolipoprotein processes, reflecting distinct stromal and immune patterns. Non-responsive tumors showed reduced expression of proteins involved in mitochondrial translation.
These findings indicate that CRLM have distinct proteomic phenotypes associated with histopathological response, largely independent of chemotherapy type, providing a foundation for biomarker discovery to predict and monitor chemotherapy efficacy.

The paper is available in the March 2026 issue of Journal of Translational Medicine. Authors are A.K. Böhm, L.M. Skrip, D. Klein, F. Strobl, J.K. Wieland, A. Arnold, Y. Zhou, B. Papke, C. Sers, D.P. Modest, S. Moosburner, P.K. Haber, F. Krenzien, N. Raschzok, W. Schöning, D. Horst, T. Malinka, I. Sack, J. Pratschke, I.M. Sauer, and K.H. Hillebrandt.

A hospital stay can be unsettling – especially in the run-up to major operations or medical procedures.  "Patient Empowerment Through Immersive Hospital Experiences before Operations or Procedures" (PERISKOP) uses immersive 360° films to bring key wards and medical care processes to life. Stereoscopic 360° videos show the environment and processes in the intensive care unit, during preparation for surgery and in obstetrics.

This gives patients the opportunity to familiarise themselves with the environment before their stay, learn about spatial and organisational processes, and experience potentially anxiety-provoking situations in advance. The aim is to reduce uncertainty, create a feeling of familiarity and support individual preparation for the hospital stay.
The project also examines how VR-supported information services can improve patient education and be integrated into clinical routine in the long term to support hospital staff.

The studies are based on three stereoscopic 360° films on the clinical areas of anaesthesia, intensive care and childbirth, produced at original locations at Charité – Universitätsmedizin Berlin. The films are not only aimed at patients: hospital staff can also use the recordings to gain the patient's perspective and thus deepen their empathy and understanding of the clinical experience. Each sub-study follows its own research design, tailored to the respective clinical situation and target group. Among other things, the studies examine preoperative anxiety, the subjective feeling of preparation, and effects on empathy and communication in everyday clinical practice. Data collection is currently underway. The project is funded by the Charité Foundation through the Max Rubner Prize 2024.

Learn more about PERISKOP via periskop.experimental-surgery.de/

We thank Stiftung Charité for their support and making this project come alive!

The study "Impact of Donor Age and Prolonged Warm Ischemia in Normothermic Machine Perfusion of Rat Livers" published in Tissue Eng Part A investigated how donor age and circulatory death affect the viability of extended criteria donor (ECD) liver grafts using a rat normothermic machine perfusion (NMP) model. Livers from young (3-month) and older (12-month) rats were subjected to 30 minutes of warm ischemia followed by 3 or 6 hours of NMP. Functional parameters, metabolic markers, histology, and proteomics were analyzed.
Key findings include:

• All grafts remained metabolically active, showing lactate clearance and bile production.
• Older livers had more acidotic perfusate pH and increased necrosis after prolonged perfusion.
• Younger livers exhibited higher transaminase release.
• Proteomic analysis revealed age- and perfusion time-dependent changes in pathways related to mitochondrial damage, oxidative stress, and immune activation, which were not consistently detected by conventional viability markers.

The study suggests that histological and molecular assessments during NMP can better capture graft injury than standard markers, supporting tailored interventions to improve ECD graft quality and potentially expand their use in transplantation amidst organ shortages and an aging donor population.
Authors are A.S. Pietsch, L. Boerger, L. Padoan, K.A. Walter, J.M. Gassner, O. Klein O, L.A. Böhne, A. Arnold, D. Horst, I. Iske, K.H. Hillebrandt, F. Krenzien, J. Pratschke, I.M. Sauer, N. Raschzok, and S. Moosburner.

The latest study "Comparison of different decellularization protocols for porcine centrum tendineum diaphragmatis and diaphragmatic muscle - a base for effective recellularization" published by B.F. Gaag, P. Tang, O. Klein, S. Moosburner, A.K. Böhm, T. Lohmann, J.K. Wieland, V. Contes, Y. Zhou, E. Keshi, L. Haderer, E. Metzler, V. Schöwel-Wolf, S. Spuler, J.C. Rückert, J. Pratschke, I.M. Sauer, M.N. Andreas, and K.H. Hillebrandt evaluated decellularization strategies for porcine diaphragm tissue to support the development of biocompatible scaffolds for diaphragmatic repair. Diaphragmatic dysfunction often requires reconstruction, but current materials have limitations such as poor biocompatibility and immune reactions. Decellularization aims to remove cells while preserving the extracellular matrix (ECM), enabling tissue engineering approaches.
Three protocols were compared:
P1: Detergent-enzymatic treatment adapted from murine diaphragm.
P2: A protocol designed for larger mammalian (human) diaphragm tissue.
P3: A protocol developed for porcine tendinous diaphragm.
All protocols significantly reduced DNA content, indicating effective removal of cellular material. Proteomic analysis identified 4,640 conserved proteins, including matrisomal proteins important for ECM structure. About 55% of the matrisomal fraction was consistently preserved across protocols. P3 preserved the most proteins, followed by P2 and P1; however, P3 did not fully meet current decellularization standards.
Overall, P1 and P2 provided effective ECM preservation while removing cellular components, with no clear superiority between them. The findings support further development of decellularized porcine diaphragm scaffolds for potential clinical application in diaphragm repair.
The paper was published in the January issue of the Journal of Biological Engineering.

The study "Overcoming the data barrier: transfer learning for 90-day mortality prediction in general surgery - a retrospective multicenter development and comparison study" was published in the January issue of the International Surgery Journal by A. Winter, B. Pfitzner, R.P. van de Water, L. Faraj, C. Riepe, W.H. Hahn, F. Krenzien, C. Schineis, T. Malinka, W. Schöning, C. Denecke, B. Arnrich, K. Beyer, J. Pratschke J, I.M. Sauer, and M.M. Maurer.

This multicenter study investigated whether transfer learning (TL) can improve AI-based prediction of 90-day postoperative mortality in general surgery, where limited datasets often hinder the development of robust models.

Data from 14,922 patients undergoing esophageal, liver, pancreatic, or colorectal surgery across three tertiary centers (2015–2023) were analyzed using 85 preoperative variables. Large source neural network models were first trained, then fine-tuned for specific surgical procedures using transfer learning. These models were compared with conventional machine learning (ML) approaches and standard clinical risk scores.
Results showed that ML models already outperformed traditional risk scores (e.g., ASA and Charlson Comorbidity Index). Transfer learning further improved performance, particularly in predicting mortality for esophageal (+38% AUPRC), liver (+14%), and pancreatic surgery (+8%). Across all models, patient age and the Charlson Comorbidity Index were the most influential predictors.
Overall, the study demonstrates that transfer learning can significantly enhance AI model performance in surgical settings with limited data, offering a promising strategy for improving preoperative risk stratification and decision-making in general surgery.

M.M. Maurer, B. Pfitzner, R.P. van de Water, L. Faraj, C. Riepe, D. Zuluaga, F. Krenzien, N. Raschzok, R. Siegel, C. Schineis, B. Arnrich, K. Beyer, J. Pratschke, I.M. Sauer, and A. Winter evaluated federated learning (FL) as a privacy-preserving approach for AI-based prediction of 90-day mortality after colorectal surgery. Limited data sharing between hospitals often restricts surgical AI development, and FL allows multicenter model training without transferring raw patient data. The study also assessed the effect of differential privacy (DP) on model performance.
Data from 2,959 patients undergoing elective colorectal surgery at three tertiary centers (2015–2021) were analyzed. Neural networks were trained locally at each center, using centralized data aggregation and distributed federated learning. Additional privacy protection was implemented using central and local differential privacy.
Results showed that federated learning performed similarly to centralized modeling, achieving comparable predictive accuracy (AUROC ~0.78 vs. 0.81). However, adding differential privacy reduced performance, with central DP causing moderate declines and local DP nearly eliminating predictive accuracy. Across models, the most influential predictors were patient age, blood parameters, and the Charlson Comorbidity Index.
Overall, the study demonstrates that federated learning can enable effective multicenter surgical AI models while preserving data privacy, though strong privacy mechanisms like differential privacy may significantly compromise model performance.

"Privacy preserving federated learning for 90-day mortality prediction in colorectal surgery: a multicenter retrospective development and comparison study" is available in International Journal of Surgery 2025;111(12):9065-9074

L. Zhao, M. Xu, A.M. Pfefferkorn, C. Erdogan, H. Schwelberger, P. Wang, P.H. Khedkar, M. Eigen, F.B. Lichtenberger, R. Catar, E.Y. Lai, F. Aigner, P.B. Persson, I.M. Sauer, A. Patzak, and M.I. Ashraf published the paper "Lipocalin-2 Restores Soluble Guanylyl Cyclase-Dependent Dilation of the Afferent Arteriole After Renal Transplantation or Ex Vivo Hypoxia/Reoxygenation in Mice" in Acta Physiologica 2025;241(8): e70077.

This study investigated whether iron-bound lipocalin-2 (holo-rLcn2) can restore soluble guanylyl cyclase (sGC)-mediated microvascular dilation in the kidney after hypoxia/reoxygenation (H/R) and kidney transplantation. Microvascular dysfunction is a key factor in ischemia/reperfusion injury, and sGC activators like cinaciguat lose efficacy after severe hypoxia.
Using isolated mouse afferent arterioles (AAs) and ex vivo kidney perfusion, the researchers tested vascular dilation following H/R and syngeneic kidney transplantation with short (30 min) or prolonged (5.5 h) cold ischemia.

• Key findings include:
• H/R impaired AA dilation, which was preserved by holo-rLcn2 but not by iron-free apo-rLcn2.
• The protective effect of holo-rLcn2 was iron-dependent, as it was reversed by the iron chelator deferoxamine.
• Kidney transplants exhibited reduced AA dilation, particularly after prolonged ischemia, but holo-rLcn2 treatment restored dilation to levels seen with shorter ischemia.
• Ex vivo kidney perfusion confirmed that holo-rLcn2 enhanced cinaciguat-induced vascular relaxation at the organ level.

Overall, the study identifies a novel role for iron-bound rLcn2 in preserving renal vascular function after ischemic injury and transplantation, likely by maintaining iron-dependent vascular mechanisms.

Organ Transplantation and Organ Donation – A Social Responsibility?
Experiences in Spain and Germany

Monday, September 15, 2025, 5:30 – 9:30 p.m.
Embajada de España | Embassy of Spain
Lichtensteinallee 1, 10787 Berlin

Organ transplantation is the therapy of choice for end-stage organ failure. Despite its life-saving potential, this therapy is not available to all patients in Germany, as a lack of willingness to donate has led to a shortage of organs. Together with the Embassy of Spain in Berlin, we would like to explore this topic further. By examining the different experiences of Spain and Germany—two European countries with very different approaches to organ donation—we aim to discuss opportunities, challenges, and possible ways to increase donation willingness. Experts in organ transplantation from both countries will highlight differences and engage in discussion with the audience.

We look forward to welcoming:
• Dr. Beatriz Domínguez-Gil, Director of the Spanish Transplant Organization (ONT),
• Dr. Luis Rodríguez-Bachiller Villaronga, Gregorio Marañón University Hospital,
• Dr. Alberto Sandiumenge Camps, Vall d’Hebrón University Hospital
• Franziska Bleis, Patient Ambassador,
• Dr. Axel Rahmel, Medical Director of the German Foundation for Organ Transplantation,
• Dr. Dr. Sandra Loder, Managing Physician, German Foundation for Organ Transplantation, and
• Prof. Dr. Johann Pratschke, Director of the Department of Surgery, Charité.
The event will be moderated by Christian Maier.

The event takes place within the framework of the special exhibition “Vessels: Infrastructures of Life” of the Berliner Medizinhistorisches Museum and Experimental Surgery | Charité, in cooperation with the Cluster of Excellence “Matters of Activity” at Humboldt University of Berlin, as part of the __matter Festival 2025. We gratefully acknowledge the generous support of Stiftung Charité.

Please register for the event here.

The number of people needing donor organs continues to grow — but there simply aren't enough to meet demand. Could the future of transplant medicine lie in the laboratory? This arte documentary offers a fascinating look at the latest breakthroughs in artificial organs and artificial hearts, with insights from Germany, Japan, and Sweden.
The documentary “A Heart on Demand?” by Marcus Fitsch explores one of modern medicine’s most urgent challenges: How can we overcome the shortage of donor organs?

The film follows groundbreaking research projects in Germany, Japan, and Sweden — including work at Berlin’s Charité and Japan’s renowned Riken Institute. Scientists there aren’t just modifying existing organs — they’re creating them entirely in the lab, custom-built and in scalable quantities. From miniature kidneys grown from stem cells to liver cells tested in animal models, and even the vision of a fully functional artificial heart, the documentary dives deep into the innovations shaping the future. Ethical questions are also front and center: What does it mean to manufacture human organs? And just how close are we to a true revolution in transplant medicine?

This is a rich, informative, and visually striking documentary that reveals how science and technology are coming together to redefine the future of healthcare.

Virtual reality (VR) and augmented reality (AR) are among the fastest-growing technologies of the 21st century. They also open up enormous opportunities for social integration: through cultural and educational offerings, through networked digital interaction spaces, or as a means of promoting citizen participation. The contributions in this volume present a wide range of application scenarios for VR and AR in the fields of education, health and public space. They demonstrate in a practical way how society, but also companies, can benefit from expanding their technological skills and taking diversity aspects into account. After all, genuine participation is only possible through a sustainable, transdisciplinary and citizen science approach.

Our book chapter ‘Human-Centred Design of Mixed Reality Applications in Medical Education – GreifbAR’ is now available in open access. Authors are Robert Luzsa, Moritz Queisner, Christopher Remde, Igor Sauer, Nadia Robertini and Susanne Mayr.

As part of the BMBF-funded project ‘Tangible Reality – Skilful Interaction of User Hands and Fingers with Real Tools in Mixed Reality Worlds’, we investigated how XR technology can be integrated into medical education. The chapter presents an interdisciplinary, XR-based training system for surgical knot tying. It describes key design principles and experiences from development and evaluation. In addition, it proposes a model for the human-centred design of comparable training applications that can also support other projects.

We warmly invite you to the opening of »Vessels. Infrastructures of Life« at the Berlin Museum of Medical History at the Charité (bmm), a group exhibition curated by Igor M. Sauer and Navena Widulin with contributions by Assal Daneshgar, Emile de Visscher, Frédéric Eyl, Karl Hillebrandt, Eriselda Keshi, Dietrich Polenz, Moritz Queisner, Iva Rešetar and Igor M. Sauer.

Vernissage
Wed, 4 June 2025, 7:00 - 10:00 pm

Exhibition
5 June – 12 October 2025 Tue, Thu, Fri, Sun, 10:00 am - 5:00 pm Wed, Sat, 10:00 am - 7:00 pm Closed on Mondays

Venue
Berliner Medizinhistorisches Museum der Charité (bmm) Virchowweg 17 10117 Berlin

What do plants, animals, humans and cities have in common? They all have vascular systems and, therefore, an infrastructure without which they would not be able to survive.

In the human body, arteries and veins move the blood together with the heart. Plants have a finely branched vascular system for the transport of water and nutrients. And cities utilize an underground network of pipelines that supply clean water and remove wastewater. The temporary exhibition, co-curated by Igor Sauer and Navena Widulin, shows how these vessels function and how they can be visualized, used and reproduced.

What can medicine learn from these natural and technical supply systems? What role does the interdisciplinary view – between biology, design, materials research and medical technology – play for regenerative medicine? And what innovative approaches can be derived from this for the development of artificial and bioartificial donor organs?

»Vessels. Infrastructures of Life« provides insights into the work of designers, material scientists and surgical researchers who are working together on solutions for the future – inspired by nature, technology and the logic of living systems. From exhibits on transplantation and regenerative medicine to examples of architecture and design, the exhibition offers exciting insights into these often-hidden structures. The objects on display correspond with those in Rudolf Virchow’s historical collection of specimens. A particular focus lies on the connections between natural vessels and human-made networks, such as the regulation of temperature in buildings or the water and wastewater supply in cities.

The temporary exhibition »Vessels. Infrastructures of Life« is a collaboration between the Berlin Museum of Medical History and the Experimental Surgery at the Charité and the Cluster of Excellence »Matters of Activity« of Humboldt-Universität zu Berlin as part of the → ＿matter Festival 2025.

Our paper, "90-Day Mortality Prediction in Elective Visceral Surgery Using Machine Learning: A Retrospective Multicenter Development, Validation, and Comparison Study" has been published online ahead of print in the International Journal of Surgery.
Authors are C. Riepe, R. van de Water, A. Winter, B. Pfitzner, L. Faraj, R. Ahlborn, M. Schulze, D. Zuluaga, C. Schineis, K. Beyer, J. Pratschke, B. Arnrich, I.M. Sauer, and M.M. Maurer

Machine Learning (ML) is increasingly being adopted in biomedical research, however, its potential for outcome prediction in visceral surgery remains uncertain. This study compares the potential of ML methods for preoperative 90-day mortality (90DM) prediction of an aggregated multi-organ approach to conventional scoring systems and individual organ models.

This retrospective cohort study enrolled patients undergoing major elective visceral surgery between 2014 and 2022 across two tertiary centers. Multiple ML models for preoperative 90DM prediction were trained, externally validated and benchmarked against the American Society of Anesthesiologists (ASA) score and revised Charlson Comorbidity Index (rCCI). Areas under the receiver operating characteristic (AUROC) and precision recall curves (AUPRC) including standard deviations were calculated. Additionally, individual models for esophageal, gastric, intestinal, liver, and pancreatic surgery were developed and compared to an aggregated approach. A total of 7,711 cases encompassing 78 features were included. Overall 90DM was 4% (n = 309). An XBoost classifier demonstrated the best performance and high robustness following external validation (AUROC: 0.86 [0.01]; AUPRC: 0.2 [0.04]). All models outperformed the ASA score (AUROC: 0.72; AUPRC: 0.08) and rCCI (AUROC: 0.81; AUPRC: 0.11). rCCI, patient age and C-reactive protein emerged as most decisive model weights. Models for gastric (AUROC: 0.88 [0.13]; AUPRC: 0.24 [0.26]) and intestinal surgery (AUROC: 0.87 [0.05]; AUPRC: 0.17 [0.09]) revealed the highest organ-specific performances, while pancreatic surgery yielded the lowest results (AUROC: 0.66 [0.08]; AUPRC: 0.22 [0.12]). A combined multi-organ approach (AUROC: 0.84 [0.04]; AUPRC: 0.21 [0.06]) demonstrated superiority over the weighted average across all organ-specific models (AUROC: 0.82 [0.07]; AUPRC: 0.2 [0.13]).

ML offers robust preoperative risk stratification for 90DM in elective visceral surgery. Leveraging training across multi-organ cohorts may improve accuracy and robustness compared to organ-specific models. Prospective studies are needed to confirm the potential of ML in surgical outcome prediction.

Michael Tummings – Artist in Residence @ Experimental Surgery – has released his latest book, Human Insights.

In this powerful work, Tummings turns his lens toward the operating theatre, capturing intimate moments of surgical intervention. His photographs explore the human body not as an object of clinical analysis, but as a site of vulnerability, resilience, and transformation. As noted by Jörg Christian Tonn, Tummings' work "reveals the mysteries of the body," offering entirely new perspectives on physical existence and the role of modern medicine.

With the consent of both patients and surgical teams of several university hospitals, Tummings was granted rare access to document procedures involving organ implants and artificial prostheses. The resulting imagery bridges the worlds of art and science, bringing us face-to-face with the beauty of the human body—beyond the rational and dissecting eye.

Human Insights invites viewers to reconsider how we see ourselves and our bodies, especially in moments of repair and healing.