The review, led by Ee Hng Ian Lim, Aaleyah Adam, and Athanasios Hassoulas of Cardiff University School of Medicine, is the first to formally appraise skill retention and operative transfer as outcomes in their own right. Previous syntheses, including recent meta-analyses by El Ashry and colleagues, Xiong and colleagues, and Farooq and colleagues, had established with reasonable consistency that AR improves technical performance during training. None of them, however, measured whether that performance persists without continued practice, or whether it carries over into live surgery. The Cardiff team searched PubMed/MEDLINE, EMBASE, the Cochrane Library, and CINAHL from January 2000 to March 2026, following PRISMA 2020 guidance and prospectively registering the protocol on PROSPERO. Of 304 records screened after de-duplication, 18 underwent full-text review and just nine studies, encompassing 324 participants, met the inclusion criteria.

The included studies spanned four specialties: five in laparoscopic or visceral surgery, two in urology, and one each in orthopaedics and neurosurgery. All were prospective comparative designs, seven of them randomised controlled trials, and all used validated assessment instruments such as OSATS, GOALS, and GEARS rather than subjective measures of confidence or satisfaction. Eligibility was deliberately strict: studies had to report skill retention beyond the immediate training session, or transfer to live intraoperative or high-fidelity ex-vivo performance. Purely virtual systems without a physical component were excluded, as were studies reporting only satisfaction outcomes. Methodological quality was assessed with the Medical Education Research Study Quality Instrument, or MERSQI, and risk of bias in randomised trials with the Cochrane RoB2 tool, with particular attention to whether outcome assessors were blinded.

On retention, the picture is encouraging but bounded. Four studies assessed performance after a delay, with intervals ranging from one to eight weeks. The strongest evidence came from Shepard and colleagues, who found that checklist scores for ultrasound-guided percutaneous nephrolithotomy access remained significantly improved from baseline at eight weeks at both lower pole and upper pole sites, with only modest, non-significant decline from post-test to retention assessment. Brinkman and colleagues found that laparoscopic training gains on the LAP Mentor II simulator were maintained without significant decline at one week. Dodier and colleagues reported that aneurysm occlusion rates in an AR-guided neurosurgical simulator improved significantly at fourteen days, though between-group comparisons did not reach significance and baseline imbalances complicated interpretation. Notably, Sugand and colleagues used a one-week washout design rather than a true retention paradigm, so the reviewers caution it cannot be read as confirmatory retention evidence.

Transfer results split along a striking line. Five studies assessed transfer to high-fidelity ex-vivo models, and four of the five favoured AR on validated instruments. All three studies assessing transfer to porcine box-trainer cholecystectomy reported significant AR advantages: Felinska and colleagues found higher global and task-specific OSATS scores; Wild and colleagues reported higher GOALS and OSATS scores along with lower complication rates of 60 percent versus 86.7 percent; and Cizmic and colleagues, across a ten-session training programme, found the AR group superior on GOALS and OSATS scores, critical view of safety achievement, completion rates, and complication rates. Chowriappa and colleagues found significantly higher GEARS scores and lower NASA-TLX time pressure and effort in AR-trained urology residents performing robot-assisted urethrovesical anastomosis, with a crossover arm replicating the findings.

Then comes the outlier that defines the field’s largest evidence deficit. Huettl and colleagues conducted the only study of any AR platform assessing performance in a live operating theatre, using real-time AR annotation during laparoscopic surgery. The result: no significant difference between AR and control groups in GOALS total scores, critical view of safety achievement, or operative time. Intriguingly, the AR group received 59.4 percent fewer gestural and 36.1 percent fewer verbal corrections from trainers, yet were rated as receiving lower-quality assistance, suggesting AR changed the structure of the teaching interaction rather than the participants’ underlying technical performance. The reviewers note several possible explanations for the divergence: ex-vivo settings strip away the unpredictable anatomy, time pressure, and consequences of error that characterise real operations, and Huettl’s real-time annotation modality differs fundamentally from the pre-operative simulation training used in every ex-vivo study.

One consistent null finding deserves attention. Operative time showed no significant difference in any of the eight studies that measured it, regardless of specialty, platform, or comparator. The authors argue this is probably a ceiling effect rather than a true null: in novice populations, duration is driven more by hesitation and error recovery than by movement quality, so AR may sharpen precision without shortening procedures. This fits the Fitts-Posner model of motor learning, in which qualitative gains precede speed and automaticity. Chowriappa’s cognitive load data, showing significantly lower perceived time pressure and effort in AR-trained participants, is at least consistent with AR functioning as a cognitive scaffold that offloads spatial information from working memory.

The methodological caveats are substantial. All nine studies scored as high quality on MERSQI, ranging from 13.5 to 16.5 out of 18, yet no study achieved an overall low-risk judgement on RoB2: seven raised some concerns and two were rated high risk, driven predominantly by unblinded outcome assessment. In Felinska’s study, gaze data annotation was performed by an unblinded assessor; in Wild’s, the training tutor assessed outcomes in real time with the AR overlay still visible, precluding blinding altogether. Randomisation sequence generation was inadequately reported in eight of nine studies. No study reported effect sizes, meaning statistical significance cannot be read as educational or clinical meaningfulness, and no study measured patient-level outcomes, complication rates in patients, or safety data. The maximum follow-up across the entire evidence base was eight weeks, leaving consolidation beyond that window entirely uncharted.

The reviewers’ conclusions are deliberately circumscribed. AR simulation produces measurable technical benefits in controlled ex-vivo and simulator-based settings, predominantly in novice learners, which justifies cautious integration as a pre-operative or early-curriculum adjunct, most defensibly for laparoscopic cholecystectomy and robotic surgery where the evidence is most internally consistent. What is not supported matters just as much: nothing demonstrates benefit beyond an eight-week horizon, procedural efficiency gains, or AR as a substitute for conventional intraoperative supervision. The highest research priority is adequately powered, pre-registered, blinded intraoperative transfer trials reaching Kirkpatrick Levels 3 and 4, alongside retention studies beyond three months, enrolment of senior trainees, mandatory effect size reporting, and standardised platform characterisation. Until then, the authors argue, AR should be treated as complementary rather than standalone, a genuinely promising but evidentially immature technology that must meet the same methodological bar as any other training intervention before system-level adoption.

Subject of Research: Augmented reality simulation for surgical skill retention and transfer to operative performance

Article Title: Augmented reality simulation for surgical skill retention and operative transfer: a systematic review

Article References: Lim, E. H. I., Adam, A., & Hassoulas, A. (2026). Augmented reality simulation for surgical skill retention and operative transfer: a systematic review. Global Surgical Education – Journal of the Association for Surgical Education, 5(1), Article 182. https://doi.org/10.1007/s44186-026-00585-5

Image Credits: AI Generated

DOI: 10.1007/s44186-026-00585-5

Keywords: augmented reality, surgical education, simulation training, skill retention, skill transfer, systematic review, laparoscopic surgery, surgical training, operating room, clinical competence, medical education, randomised controlled trials

Ovarian microcystic stromal tumor is exceptionally rare. Since it was first delineated as a distinct entity, only a limited number of cases have been documented in the medical literature worldwide. The tumor belongs to the broad family of ovarian stromal neoplasms, which arise from the supportive tissue of the ovary rather than from the egg cells themselves. What distinguishes MCST is its striking microscopic appearance: the tumor is composed of sheets and nests of relatively uniform cells arranged around a network of tiny, fluid-filled microcysts that give the lesion its name. Under the microscope, this architecture can resemble other ovarian tumors, including yolk sac tumor or even certain metastatic cancers, which historically made diagnosis challenging.

The key to recognizing MCST lies in its immunohistochemical fingerprint. Tumor cells in these lesions characteristically show nuclear expression of β-catenin, a protein that serves as a hallmark feature and helps separate MCST from its many microscopic mimics. The tumors also typically express Cyclin D1, CD10, vimentin, WT1, FOXL2, and SF1, a constellation of markers that pathologists use to confirm the diagnosis and to exclude other possibilities. Despite this growing list of identifying features, the biological behavior and molecular underpinnings of MCST remain incompletely characterized, largely because so few cases exist to study. Most reported tumors have behaved in a benign fashion, and conservative surgical management has generally proven sufficient.

The newly reported case involved a 38-year-old woman who had never been pregnant and who carried a history of irregular menstruation. Her ovarian mass was discovered incidentally, meaning it was found without the patient having shown symptoms directly attributable to the tumor. An initial intraoperative frozen-section examination pointed to a benign sex cord-stromal tumor, allowing the surgical team to proceed with a laparoscopic tumor enucleation, a fertility-sparing approach in which the tumor is shelled out while the ovary is preserved. This minimally invasive strategy reflects the growing recognition that, in carefully selected patients with apparently benign ovarian lesions, organ-preserving surgery can offer excellent outcomes without the need for more radical procedures.

Definitive histopathological examination confirmed the diagnosis of microcystic stromal tumor. The tumor displayed the characteristic morphology and the expected immunoprofile, with positivity for β-catenin, Cyclin D1, CD10, vimentin, WT1, FOXL2, and SF1. But two findings set this case apart. First, the tumor cells showed partial positivity for S100, a calcium-binding protein commonly expressed in neural, melanocytic, and certain other tissues, and one that is not typically associated with MCST. Second, and perhaps more strikingly, the tumor exhibited what the authors describe as a distinctive hormone receptor signature: androgen receptor was strongly expressed in approximately 90 percent of tumor cell nuclei, while progesterone receptor was weak, present in only about 15 percent of cells.

Androgen receptor expression in ovarian tumors carries particular interest because the androgen receptor participates in signaling pathways relevant to ovarian physiology and ovarian carcinogenesis. Its strong expression in this MCST raises questions about whether hormone signaling might play a role in the growth or regulation of these tumors, or whether the finding represents an incidental epiphenomenon without clinical consequence. Similarly, S100 expression introduces a diagnostic wrinkle: S100 positivity can suggest alternative diagnoses, including neural tumors or melanocytic lesions, and its partial presence in an otherwise classic MCST underscores the importance of interpreting immunohistochemical panels in context rather than relying on any single marker. Although androgen receptor expression has been reported in MCST before, and focal S100 positivity has been documented in at least one prior case, the co-existence of both features in a single tumor has only rarely been recorded.

The clinical course of the patient adds a reassuring dimension to the report. Following her laparoscopic enucleation, she recovered well, and follow-up at 28 months revealed no evidence of recurrence. This outcome is consistent with the prevailing understanding of MCST as a typically indolent neoplasm, and it supports the feasibility of conservative surgery combined with careful long-term surveillance in affected patients. For a young woman whose tumor was detected before any malignant transformation or complication, the preservation of ovarian tissue represents a meaningful quality-of-life benefit, and the extended recurrence-free follow-up provides additional confidence in the benign trajectory of this tumor type.

The authors of the report paired their case with a review of the existing literature, aiming to consolidate what is known about the clinicopathological features of MCST and its unusual immunophenotypic variants. Because the entity is so rare, individual case reports effectively serve as the primary source of knowledge, each one contributing data points that slowly refine the diagnostic criteria and the understanding of biological behavior. The review situates the present case within this accumulating record, noting both the consistency of core features—microcystic architecture, nuclear β-catenin, and benign behavior—and the variability in secondary findings such as hormone receptor status and unexpected marker expression.

The report also highlights the practical implications for diagnostic pathology. Pathologists confronting an ovarian microcystic lesion must distinguish MCST from a differential diagnosis that includes yolk sac tumor, juvenile granulosa cell tumor, and clear cell carcinoma, among others. Unusual immunostaining results, such as partial S100 positivity, could easily send the diagnostic workup down an erroneous path if not weighed against the full morphological and immunophenotypic picture. Cases like this one, in which atypical marker expression arises within an otherwise typical tumor, help calibrate the diagnostic thresholds that practicing pathologists apply, reducing the risk of both overdiagnosis and missed diagnosis.

For now, the biological significance of the combined androgen receptor and S100 expression observed in this tumor remains unresolved. The authors emphasize that larger case series will be needed to determine whether such immunophenotypic variation carries any prognostic or therapeutic relevance, or whether it simply reflects the natural heterogeneity of a rare neoplasm. In the meantime, the case stands as a reminder of how much remains to be learned about even the quietest corners of tumor biology—and of how a single carefully documented patient can meaningfully advance the field. The 28-month disease-free outcome offers comfort to patients facing similar diagnoses, while the unusual molecular profile offers scientists a fresh line of inquiry into the mechanisms that drive this enigmatic ovarian tumor.

Subject of Research: A rare benign ovarian stromal neoplasm exhibiting an atypical immunophenotype with androgen receptor and partial S100 expression

Article Title: Ovarian microcystic stromal tumor with unusual expression of AR and partial S100: a case report and literature review

Article References: Liu, M., Sun, Y., Yin, J., Liu, K., & Jiang, Z. (2026). Ovarian microcystic stromal tumor with unusual expression of AR and partial S100: a case report and literature review. Journal of Ovarian Research. https://doi.org/10.1186/s13048-026-02276-7

Image Credits: AI Generated

DOI: 10.1186/s13048-026-02276-7

Keywords: ovarian tumor, microcystic stromal tumor, MCST, androgen receptor, S100, β-catenin, immunohistochemistry, sex cord-stromal tumor, case report, ovarian pathology, laparoscopic surgery, Journal of Ovarian Research

The research team, led by authors including Yudai Fukui, Koya Hida, Marie Hanaoka, and Yusuke Kinugasa, screened 438 records and ultimately synthesized 29 studies, comprising 20 observational investigations, four reports from randomized trials, and five systematic reviews or meta-analyses. Rather than pooling heterogeneous data into a single meta-analysis, which the authors argue would obscure clinically meaningful differences, they stratified the evidence by clinical setting, operative strategy, and patient risk profile. This framework allowed them to separate the true effects of the surgical approach itself from the powerful influence of patient selection, disease severity, and institutional expertise, factors that have long muddied comparisons between the two techniques.

The strongest evidence comes from the elective setting, where patients undergo planned sigmoid resection after recurrent episodes of diverticulitis. Randomized trials, including the landmark Dutch Sigma trial of 104 patients, demonstrated that laparoscopic sigmoidectomy reduced major morbidity, lessened early postoperative pain, shortened hospitalization, and sped recovery compared with open surgery. A Cochrane review of three randomized trials involving 392 patients confirmed that laparoscopy may reduce pain, though with low certainty and a notable trade-off: operative times ran nearly 50 minutes longer on average. Yet the review also highlights a sobering caveat. Mid- and long-term follow-up studies from these same trials found no clear differences in mortality, gastrointestinal function, or quality of life, and economic analyses from the Sigma trial showed that higher operative costs for laparoscopy were offset only to the point of comparable overall healthcare spending, not savings.

Large real-world database studies reinforce the short-term picture. Analyses of more than 124,000 elective colectomies in the Nationwide Inpatient Sample and nearly 7,700 cases in the American College of Surgeons NSQIP registry found lower postoperative morbidity, fewer wound complications, shorter hospital stays, and lower hospital charges with laparoscopy. For complicated diverticulitis specifically, a cohort of nearly 12,000 patients showed that the morbidity advantage was most pronounced among those receiving primary anastomosis. These observational findings are impressively consistent, but the authors caution that residual confounding by indication, the tendency to offer keyhole surgery to fitter patients with less severe disease, remains an unavoidable limitation of nonrandomized data.

The emergency setting is where the review delivers its most striking and clinically consequential findings. In one large NSQIP analysis of 9,194 emergent colectomies for diverticulitis, minimally invasive surgery was associated with significantly fewer major adverse events, 42.0 percent versus 56.4 percent, an adjusted odds ratio of 0.56, along with lower 30-day mortality of 4.1 percent versus 8.8 percent, dramatically lower ostomy formation at 35.8 percent versus 84.8 percent, fewer ileus cases, and shorter hospital stays of a median 7 versus 9 days. In selected cohorts, even operations that began laparoscopically and converted to open surgery were not associated with worse outcomes than planned open procedures, challenging the long-held assumption that conversion signals failure. Hospital volume emerged as a key modifier, with higher minimally invasive surgical volumes linked to lower conversion rates.

For perforated diverticulitis, the review’s most technically detailed domain, outcomes depended sharply on which operation was performed. In a propensity score-matched cohort of patients with purulent or fecal peritonitis, laparoscopic sigmoidectomy achieved lower overall morbidity of 44 percent versus 66 percent, shorter hospitalization of 7 versus 9 days, far fewer wound infections at 3 percent versus 29 percent, and a higher 12-month probability of being stoma-free among Hartmann procedure patients, 0.88 versus 0.64. By contrast, laparoscopic Hartmann procedures showed only limited advantages, chiefly reduced superficial surgical site infections, without consistent reductions in mortality or major complications. Most provocatively, the review concluded that laparoscopic lavage and drainage, a strategy of washing out the abdomen without removing the diseased segment, cannot be considered equivalent to laparoscopic resection, with comparative evidence suggesting lavage-based approaches may carry more frequent severe complications than open resection.

High-risk populations received special attention, and here the observational associations were among the most favorable. In cirrhotic patients undergoing colectomy for acute diverticulitis, laparoscopy was linked to lower mortality, shorter stays, and reduced costs. Among patients with respiratory comorbidities, hospital stays were dramatically shorter with laparoscopy, 5.3 versus 9.5 days in smokers, 6.8 versus 11.1 days in patients with dyspnea, and 7.4 versus 12.6 days in those with chronic obstructive pulmonary disease. In elderly patients, laparoscopic surgery reduced 30-day morbidity in both elective and non-elective settings, with odds ratios of 0.47 and 0.76 respectively, alongside fewer surgical site infections and shorter admissions. The authors repeatedly stress, however, that preferential selection of physiologically fitter patients for keyhole surgery may substantially inflate these apparent benefits.

Procedure-specific findings extended the favorable pattern to fistulizing disease and right-sided diverticulitis. A meta-analysis of diverticular colovesical fistulas, where the inflamed colon has eroded into the bladder, found fewer total postoperative complications with laparoscopy, an odds ratio of 0.55, and hospital stays nearly three days shorter, while mortality, anastomotic leak, and stoma rates remained comparable. A multicenter German study of fistulizing recurrent diverticulitis confirmed faster bowel recovery and shorter intensive care stays. For right-sided disease, a less common variant typically managed differently from sigmoid diverticulitis, NSQIP data showed comparable morbidity with shorter hospitalization after minimally invasive resection, and small comparative studies supported feasibility in selected complicated cases.

On the intraoperative front, the review found less to celebrate. Laparoscopic surgery consistently required longer operative time, with a matched perforated-disease cohort showing 127 versus 96.5 minutes, and while blood loss appeared numerically lower in several studies, evidence that laparoscopy reduces intraoperative complications remains insufficient. Questions about ureteral injury, a feared complication in inflamed diverticular fields, could not be answered definitively, though the authors note that fluorescence-guided ureter visualization techniques are attracting growing interest even as their protective value remains unproven.

The review’s ultimate contribution is a decision-making framework rather than a verdict. Laparoscopy offers its clearest and best-supported benefits in elective surgery, meaningful promise in selected emergency resections, perforated disease treated with resection rather than lavage, high-risk patients, fistulizing disease, and right-sided cases, while its role in Hartmann procedures and lavage-based strategies is far more uncertain. The authors emphasize that in emergency surgery, rapid and reliable source control of infection must take priority over completing a minimally invasive procedure, and that conversion to open surgery should be regarded as an appropriate safety decision rather than a technical failure. They also acknowledge their study’s limitations, including the absence of a formal risk-of-bias assessment, the exclusion of robotic surgery, and the reality that observational findings represent associations rather than causal proof. The choice of surgical approach, they conclude, should be driven not by technique alone but by the interplay of disease severity, patient condition, operative strategy, and institutional expertise, a conclusion that reframes the laparoscopic-versus-open debate as a question of matching the right operation to the right patient rather than crowning a single winner.

Subject of Research: Comparative outcomes of laparoscopic versus open surgery for colonic diverticular disease across elective, emergency, perforated, and high-risk clinical settings

Article Title: Laparoscopic Versus Open Surgery for Diverticular Disease: A Structured Review Across Clinical Settings and Operative Strategies

Article References: Hanaoka, M., Fukui, Y., Hida, K., Takeuchi, H., & Kinugasa, Y. (2026). Laparoscopic Versus Open Surgery for Diverticular Disease: A Structured Review Across Clinical Settings and Operative Strategies. Annals of Gastroenterological Surgery, Article ags3.70285. https://doi.org/10.1002/ags3.70285

Image Credits: AI Generated

DOI: 10.1002/ags3.70285

Keywords: diverticular disease, diverticulitis, laparoscopic surgery, open surgery, colectomy, sigmoidectomy, Hartmann procedure, laparoscopic lavage, emergency surgery, perforated diverticulitis, stoma creation, surgical outcomes

Small bowel obstruction is far from a niche problem. Postoperative adhesions account for an estimated 12 to 16 percent of surgical admissions in the United States, and comparable burdens have been documented in Swedish and Korean registry data. Management is frequently prolonged, may require reoperation or extensive bowel resection, and carries an operative mortality approaching 5 percent, alongside impaired nutrition and reduced quality of life for survivors. Despite this clinical and economic toll, standardized prevention strategies remain elusive, and current practice depends largely on surgeon preference rather than high-quality evidence.

The biological logic behind the new findings is straightforward. Postoperative obstruction arises primarily when the parietal and visceral peritoneum, the slippery membranes lining the abdominal cavity and covering the organs, are damaged during surgery, prompting scar tissue formation. Laparoscopic surgery, performed through small incisions with camera guidance, minimizes peritoneal trauma. Adhesion prevention materials, such as the hyaluronic acid-carboxymethylcellulose film Seprafilm, act as physical barriers between injured peritoneal surfaces during healing. Yet randomized trials, including the influential COLOR II trial of rectal cancer, had failed to show that laparoscopy significantly reduces obstruction, partly because laparoscopy reduces parietal adhesions more effectively than visceral ones.

To resolve these uncertainties, the researchers drew on a nationwide retrospective survey covering 18,798 gastrointestinal surgeries across 32 institutions, of which 5811 involved colorectal disease. After excluding benign conditions and incomplete records, 5458 patients with histologically confirmed colorectal cancer remained. Of these, 3193 patients, or 58.5 percent, underwent laparoscopic surgery, while 2265, or 41.5 percent, had open operations. Over five years of follow-up, 283 cases of small bowel obstruction were identified, defined as clinically diagnosed obstruction requiring hospitalization and fasting for more than one day, with suspected cancer recurrences excluded.

Because patients were treated at many different hospitals, the team used mixed-effects logistic regression with hospital as a random intercept, a statistical technique that accounts for institutional clustering and prevents any single center from distorting the results. The model adjusted for age, sex, tumor location, and stoma creation. The headline result was striking: laparoscopic surgery was independently associated with a 42 percent reduction in the odds of developing obstruction compared with open surgery, with an adjusted odds ratio of 0.58 and a confidence interval of 0.45 to 0.74, highly statistically significant. In absolute terms, the risk fell from 6.8 percent with open surgery to 4.1 percent with laparoscopy, an absolute risk reduction of 2.7 percent, equivalent to a number needed to treat of 37.

That last figure deserves unpacking for readers unfamiliar with clinical epidemiology. A number needed to treat of 37 means that for every 37 patients shifted from open to laparoscopic surgery, one case of small bowel obstruction would be prevented over five years. The benefit, however, was not uniform across the bowel. Site-specific analyses revealed statistically significant reductions in ascending colon surgery, where the number needed to treat dropped to 22.2, and in sigmoid colon surgery, at 30.2. No significant reduction was seen in the cecum, transverse colon, descending colon, or rectum. The transverse colon, highly mobile and often requiring omental dissection, may blunt laparoscopy’s advantage, while rectal surgery involves deep pelvic dissection, frequent stomas, and possible neoadjuvant radiotherapy, all of which complicate the picture.

In contrast to the laparoscopy findings, adhesion prevention materials were a clear null result. Seprafilm, the only such product approved for gastrointestinal surgery in Japan during the study period, showed no significant association with reduced obstruction, with an adjusted odds ratio of 1.01 and a p-value of 0.94. When patients were stratified by surgical approach, obstruction rates were nearly identical with and without the film in both laparoscopic and open groups. Usage varied dramatically across hospitals, from 0 to 99.2 percent, and surgeons applied it at their own discretion, raising the possibility of confounding by indication, in which the film was preferentially used in the most complex, highest-risk operations, potentially masking a genuine benefit. Still, the findings echo a randomized trial that likewise found no significant obstruction reduction with the material in colorectal cancer patients.

Perhaps the most clinically provocative finding concerned stomas. Patients who received a stoma, a surgical opening of the bowel through the abdominal wall, faced an 84 percent increase in the odds of obstruction, with an odds ratio of 1.84. Among rectal cancer patients, 11.4 percent of those with stomas developed obstruction versus 5.1 percent of those without. Notably, the risk was similar for ileostomies, at 13.2 percent, and colostomies, at 10.6 percent, suggesting that the presence of a stoma itself, rather than its type or fluid output, is the key driver. The mechanism likely involves both additional peritoneal trauma from stoma creation and closure and non-adhesive problems such as kinking at the abdominal wall passage or parastomal hernia. The authors argue that stoma creation warrants judicious use, reserved for cases where the danger of anastomotic leakage clearly outweighs the obstruction risk.

Tumor location emerged as an independent determinant in its own right. Rectal cancer carried the highest obstruction incidence at 6.8 percent, and all colonic sites except the descending colon showed significantly lower odds than the rectum. This pattern reflects surgical anatomy: total mesorectal excision in the confined pelvic space, often combined with radiotherapy and stomas, promotes adhesion formation, while descending colon resections demand splenic flexure mobilization and extended dissection. Sigmoid colon surgery, despite its anatomical proximity to the rectum, enjoyed lower risk, plausibly because of more straightforward operative planes and fewer stomas.

The study’s statistical rigor extended to sensitivity analyses. E-value calculations, which estimate how strong an unmeasured confounder would need to be to erase the observed associations, reached 2.84 for laparoscopic surgery and 3.08 for stoma creation, indicating reasonably robust findings, while the E-value of 1.11 for adhesion films was consistent with a true null effect. Nonetheless, the authors are candid about limitations. The retrospective, non-randomized design cannot prove causation, and variables such as body mass index, tumor stage, diabetes, neoadjuvant therapy, prior abdominal surgery, and emergency operations were unavailable. Because factors like advanced stage and obesity push surgeons toward open surgery while independently raising adhesion risk, confounding, if present, would tend to overstate laparoscopy’s protective effect, not undermine it. The binary five-year endpoint also prevented time-to-event analysis, could not distinguish early from late obstruction, and did not capture obstruction severity or episodes occurring decades later.

Even with those caveats, the study’s implications are substantial. It suggests that the benefits of minimally invasive colorectal cancer surgery extend beyond the well-established short-term advantages of less pain and faster recovery into meaningful long-term protection against bowel obstruction, particularly in ascending and sigmoid colon resections. It casts serious doubt on the routine use of adhesion barrier films under current, unstandardized practice patterns, and it flags stoma creation as a modifiable risk factor deserving careful weighing. As robotic platforms, refined laparoscopic techniques, and enhanced recovery protocols spread, the balance of risks may shift further, and the authors call for prospective studies with time-to-event data reflecting contemporary practice. For now, the message to surgical teams is clear: the route taken through the abdominal wall may echo in a patient’s health for years to come.

Subject of Research: The association of laparoscopic surgery, adhesion prevention materials, and stoma creation with five-year small bowel obstruction risk after colorectal cancer surgery.

Article Title: Laparoscopic Surgery Is Associated With Reduced Small Bowel Obstruction Risk After Colorectal Cancer Surgery: A Nationwide Cohort Study of 5458 Patients

Article References: Yamada, T., Fujita, F., Eto, K., Kataoka, K., Yukawa, N., Sugimoto, K., Shimoyama, R., Fukazawa, A., Kumamoto, K., Takayama, Y., Komono, A., Matsuda, A., Ohta, R., Sonoda, H., Okuya, K., Ihara, K., Yokoyama, Y., Nishino, T., Akiyama, Y., & Ichikawa, D. (2026). Laparoscopic Surgery Is Associated With Reduced Small Bowel Obstruction Risk After Colorectal Cancer Surgery: A Nationwide Cohort Study of 5458 Patients. Annals of Gastroenterological Surgery, Article ags3.70280. https://doi.org/10.1002/ags3.70280

Image Credits: AI Generated

DOI: 10.1002/ags3.70280

Keywords: colorectal cancer, laparoscopic surgery, small bowel obstruction, adhesions, adhesion prevention materials, stoma, open surgery, nationwide cohort study, surgical outcomes, Seprafilm, rectal cancer, postoperative complications

The study, published in the Journal of Industrial Ecology, used a research-through-design approach to develop four alternative concepts for a single-use powered linear laparoscopic stapler: a fully recyclable device, a partially reusable device, a multifunctional device with interchangeable modules, and a manual device stripped of its electronics. Each concept was evaluated with fast-track life cycle assessments and scrutinized by both Medtech industry experts and a broader group of ten stakeholders spanning clinical, sustainability, technical, and business perspectives. The goal was not to produce a final product but to systematically map where circular design collides with the non-negotiable demands of healthcare: patient safety, clinical performance, usability, regulatory compliance, and financial viability.

The environmental case for redesign is compelling. Previous research has shown that switching from single-use to multi-use surgical staplers can reduce waste by 40 percent and material requirements by 92 percent in laparoscopic sleeve gastrectomy. Hybrid laparoscopic instruments that combine reusable and disposable parts have been shown to carry a carbon footprint of roughly 1,756 grams of CO2-equivalent per operation, compared with 7,194 grams for single-use equivalents, a 75 percent reduction. Yet powered staplers are far more technically complex than those instruments, embedding printed circuit boards and batteries that dominate their manufacturing footprint. The new study’s baseline life cycle assessment confirmed that manufacturing impacts, particularly the production of electronics, were the largest contributors, with transport impacts close behind because assembly, sterilization, and use occur in different countries, including assumed air freight from a United States distribution center to hospitals in Belgium.

The life cycle modeling, performed in SimaPro using Ecoinvent v3.9.1 data and the Environmental Footprint 3.0 impact method, compared each concept against the baseline over 50 use cycles, the maximum reuse figure specified by manufacturers for reusable laparoscopic instruments. The results were striking. The multifunctional and manual designs could theoretically reduce environmental impacts by 80 to 90 percent, either by eliminating electronic components altogether or by consolidating multiple functions into a single reusable electronics module paired with separate metal actuator modules. The partially reusable device, which extends the life of the electronics while keeping the housing disposable, offered a moderate improvement. The fully recyclable single-use device, despite being engineered for disassembly and material recovery, delivered almost no carbon benefit, because the dominant manufacturing impacts of the electronics remained untouched.

Perhaps the most provocative finding concerns the gap between environmental performance and stakeholder preference. The Medtech experts rated the recyclable device as their overall favorite, precisely because it resembled existing products and could slot into familiar clinical workflows and regulatory pathways, even though it offered the least carbon reduction. Broader stakeholders, by contrast, rejected it for exactly that reason, warning that plastic recycling remains economically limited when virgin materials are cheap and that reliance on virgin feedstocks carries significant transport and material costs. Meanwhile, the multifunctional device, with one of the lowest estimated footprints, was judged technically infeasible by industry experts due to differences in circuitry and actuation, and stakeholders flagged logistical complexity, inventory tracking difficulties, and regulatory hurdles around reprocessing components. Yet the surgeon participating in the study named the multifunctional concept his preferred option, citing its usability and practicality, a direct contradiction of assumptions voiced by other participants about what surgeons would accept.

The partially reusable device emerged as a pragmatic middle ground. Half of the surveyed stakeholders named it their favorite, praising its ability to cut electronic waste while leaving design and logistics largely unchanged. Comments included observations that staff would only need to charge a battery as an extra step and that a single-use housing would likely still comply with existing frameworks. Industry experts, however, cautioned that charging and reassembly steps could introduce risks around maintenance, reliability, and aseptic transfer, the process of moving materials without contamination, and warned that perceived risks of reusing contaminated components could trigger user resistance, even though in practice the electronics module never contacts bodily fluids. This tension between perceived and actual risk recurred throughout the study and echoes earlier findings that barriers to sustainable medical device design are often more perceptual than factual.

The manual device presented a different kind of dilemma. Removing electronics entirely yields the lowest theoretical carbon footprint and, according to stakeholders, simpler logistics with no complex waste management required, no battery charging, and potential alignment with emerging sustainability regulations. Some even suggested it could enable pay-per-use business models in which hospitals or manufacturers capture value through per-surgery pricing. But Medtech experts were blunt: powered staplers exist for ergonomic and performance reasons, and achieving comparable precision and consistency through mechanical means would be highly challenging. They also noted that any increase in surgical complications could raise the total cost and carbon footprint of the entire patient journey, since treating complications is part of care delivery. The lesson, the researchers argue, is not that manual designs are off the table, but that any such redesign must identify which electronic functions are essential and find smart mechanical alternatives that preserve performance.

Beyond the concept comparisons, the study cataloged recurring trade-offs organized by the underlying circular intervention, whether enabling reuse, reducing electronics, multifunctional design, or improving traceability. Common drawbacks included increased sterilization burden, altered surgical workflow, reduced user familiarity, and regulatory complexity around reprocessing. But the researchers also documented a set of genuine synergies in which circular strategies improved environmental and operational outcomes simultaneously. Reuse can lower material and logistics costs by extending the life of high-value components, improve alignment with emerging regulations, and generate long-term savings despite higher upfront investment. Eliminating or reducing electronics can simplify production, reduce failure risks in the operating room, enhance sterilization compatibility, and make devices more intuitive for staff. Circular design, the study concludes, does not always involve sacrifice.

The authors are careful to acknowledge the limits of their work. The analysis examined a single device type, relied on conceptual designs rather than physical prototypes, and used fast-track life cycle assessments whose assumptions about reuse cycles, sterilization intensity, and maintenance requirements are key uncertainty drivers. The stakeholder sample of ten was purposive rather than statistically representative, and the differing scoring scales used for experts and survey participants constrained direct comparison. The life cycle results should be read as a comparative assessment of the relative potential of circular strategies, not precise predictions. Future research, the team suggests, should include prototyping, user testing, sensitivity analyses, and the development of a circular design guide for medical devices that embeds trade-off mapping at each stage of product development, alongside exploration of take-back models, product-as-a-service approaches, and service-based sterilization arrangements.

The broader significance of the study lies less in the four stapler concepts themselves than in the decision-making process it demonstrates. By pairing quantitative life cycle modeling with structured stakeholder evaluation, the researchers showed that sustainability, technical feasibility, clinical usability, and regulatory compliance act as separate filters on design ideas, and the best overall design rarely maximizes any single criterion. They argue that companies should model the environmental consequences of their choices just as they already model financial and clinical ones, and that even when the most sustainable option is not chosen, it can point the way from today’s incremental strategies toward more transformative circular redesigns. Regulatory frameworks such as the European Medical Device Regulation and the Waste Electrical and Electronic Equipment Directive will shape what is possible, and procurement policies that consider lifecycle value rather than upfront cost could accelerate adoption. For a sector under growing pressure to shrink its climate footprint while safeguarding patients, the message is clear: the path to circular medical devices runs not through engineering alone, but through a systems-level alignment of design, regulation, clinical practice, and business incentives.

Subject of Research: Circular design trade-offs and carbon footprint reduction in single-use powered laparoscopic surgical staplers

Article Title: Balancing trade-offs in circular medical device design: a case study on laparoscopic devices

Article References: Hoveling, T., Muindi, N., Faludi, J., & Bakker, C. (2026). Balancing trade-offs in circular medical device design: a case study on laparoscopic devices. Journal of Industrial Ecology. https://doi.org/10.1007/s44498-026-00189-8

Image Credits: AI Generated

DOI: 10.1007/s44498-026-00189-8

Keywords: circular economy, medical devices, laparoscopic surgery, life cycle assessment, sustainable healthcare, surgical staplers, e-waste, research through design, carbon footprint, regulatory compliance, medical device design, reuse and recycling

The peg transfer task is deceptively simple to describe. Using a pair of laparoscopic graspers, a trainee must pick up small objects, transfer them between the left and right instruments, and place them on a pegboard, all while viewing the field only through a camera that removes natural depth perception. Speed and precision both matter, and expert raters have long used the task to distinguish novices from seasoned minimally invasive surgeons. Previous research has established that simulator performance on FLS tasks predicts intraoperative laparoscopic skill, which is precisely why the program carries such weight in certification. But the same research literature has also documented how resource-intensive human assessment can be, motivating a decades-long search for automated, objective measures of surgical motion, from early motion-analysis studies to modern deep learning approaches that interpret surgical video directly.

To build their dataset, the researchers recorded general surgery residents and medical students at an academic medical center performing the peg transfer task on camera. In total, 132 videos were captured. Two adjudicators then independently scored each recording as beginner, intermediate, or expert, basing their judgments on task duration and the perceived technical quality of the performance. This human labeling step is crucial: in supervised machine learning, the algorithm can only be as good as the ground truth it learns from, and the use of two independent adjudicators helps ensure the labels reflect genuine consensus about skill level rather than one rater’s idiosyncrasies. Of the 132 recordings, 100 were ultimately used for analysis, while 32 were excluded because of tracking dropout, a reminder that even mature computer vision systems can lose track of instruments when visibility degrades or movements become ambiguous.

Technically, the pipeline rests on several components that have become standard tools in modern computer vision. The team used Ultralytics YOLOv8 for object detection, identifying and localizing the laparoscopic instruments frame by frame, and paired it with ByteTrack, a multi-object tracking algorithm that associates detection boxes across consecutive frames to maintain consistent identities for each instrument through time. From these tracked trajectories, the system extracted three quantitative input features: task duration, instrument path length, and peg displacement. These features distill an entire performance into the quantities that surgical educators have long recognized as meaningful. Shorter completion times and shorter instrument travel distances have historically correlated with higher technical skill, while peg displacement captures the physical consequences of the surgeon’s actions on the training board itself. A gradient boosting classifier, LightGBM, then mapped these features to skill level labels.

The model was trained under five-fold cross-validation, a rigorous scheme in which the data are split into five subsets and the model is repeatedly trained on four while being tested on the fifth, so that every recording serves as an unseen test case. The results were strong. Overall classification accuracy reached 84 percent, and, notably, the model made almost no beginner-to-expert misclassifications, meaning it essentially never confused the least skilled performers with the most skilled ones. The macro-averaged area under the curve, a measure of the model’s ability to discriminate across classes, came in at 0.907 plus or minus 0.061. Broken down by class, the AUC was 0.971 for beginners, 0.850 for intermediates, and 0.900 for experts, indicating that the extremes of the skill spectrum were the easiest to identify while the middle category, as is often the case in ordinal classification problems, posed the greatest challenge.

A threshold-based variant of the classifier, which converts the model’s probability outputs into hard class assignments, achieved a macro F1-score of 0.83 and, strikingly, a precision of 0.96 when identifying experts. In practical terms, when the system declares a performance expert-level, it is right nearly every time. That property matters for real-world deployment in surgical education. A tool that occasionally under-recognizes an intermediate performer but almost never inflates a novice to expert status is far safer for high-stakes feedback than one with symmetric error rates. The authors suggest that their AI-enabled computer vision model may offer a scalable supplement to traditional expert-based evaluation, potentially increasing opportunities for trainee feedback without adding to faculty workload.

The significance of that scalability claim becomes clear when considering the structure of American surgical training. Because successful FLS completion is a prerequisite for board qualification, residents across the country must prepare for and pass the exam, and studies have shown that doing so improves operative performance and autonomy while boosting junior residents’ self-efficacy. Yet feedback during preparation typically requires a faculty surgeon to watch practice runs, an expensive use of attending physician time that caps the frequency of assessment. A vision-based system that can watch unlimited repetitions and deliver consistent, quantified scores could allow residents to practice more deliberately, tracking their trajectory from beginner toward expert using objective metrics rather than intermittent impressions. The authors argue that implementing such AI-enabled assessment systems may enhance the accessibility of feedback and promote technical skill development across training programs, not just at well-resourced academic centers.

The study also situates itself within a rapidly expanding body of work on artificial intelligence in surgery. A 2024 review in Nature Medicine charted the broad scope of AI applications across the surgical lifecycle, and recent projects have applied deep learning to simulated laparoscopic skill assessment, video-based formative and summative evaluation of surgical tasks, and competency gauging on novel laparoscopic training systems. Earlier efforts demonstrated that 3D convolutional neural networks could assess skill directly from raw video, while other teams built software-based motion tracking tools for the surgical skills assessment landscape. What distinguishes the new UCLA approach is its deliberate parsimony: rather than feeding entire video streams into a heavyweight neural network, the researchers reduced each performance to three interpretable features derived from instrument tracking. This design choice makes the model’s decisions easier to audit and explain to educators, an important consideration as AI tools move closer to credentialing processes.

The choice of features also connects the work to foundational research in surgical education. Landmark studies by Datta and colleagues at Imperial College showed decades ago that motion analysis metrics correlate strongly with expert technical assessments, and randomized trials demonstrated that FLS simulator training to proficiency translates into improved laparoscopic performance in the operating room. By automating the extraction of duration, path length, and displacement, the new system operationalizes those validated constructs at scale, converting what once required laboratory motion-tracking equipment into something achievable with a standard camera and open-source detection and tracking software. The exclusions for tracking dropout, however, highlight remaining engineering challenges: lighting, camera angle, occlusion, and instrument visibility all still influence whether the pipeline can reliably follow tools through a complete performance.

The research team, led by corresponding author Terrance Peng of UCLA and including collaborators from Cedars-Sinai Medical Center, reports no conflicts of interest related to the project. The authors caution that their model was developed and validated on recordings from a single academic medical center, and broader validation across institutions, camera setups, and trainee populations will be needed before such systems can assume a formal role in summative assessment. Privacy considerations also shape the field: the video recordings generated for the study are not publicly available, with additional data available only on reasonable request. Still, the trajectory of the results, 84 percent accuracy, near-zero confusion between skill extremes, and 96 percent expert precision, suggests that AI-assisted surgical assessment is moving from proof-of-concept toward practical tool. If future systems match this performance in everyday training environments, the hours faculty spend watching peg transfers could be redirected toward higher-value teaching, while residents gain the luxury of feedback after every single repetition, a shift that could quietly reshape how the next generation of surgeons learns to operate.

Subject of Research: Artificial intelligence-based computer vision assessment of laparoscopic surgical skill on the FLS peg transfer task

Article Title: Artificial intelligence-enabled evaluation of laparoscopic peg transfer performance

Article References: Peng, T., Alipour, A., Desai, K., Chen, D., Huang, G., Rosenthal, R. J., Barmparas, G., Chen, Y., & Benharash, P. (2026). Artificial intelligence-enabled evaluation of laparoscopic peg transfer performance. Global Surgical Education – Journal of the Association for Surgical Education, 5(1), Article 173. https://doi.org/10.1007/s44186-026-00580-w

Image Credits: AI Generated

DOI: 10.1007/s44186-026-00580-w

Keywords: artificial intelligence, computer vision, laparoscopic surgery, surgical education, FLS, peg transfer, skills assessment, machine learning, surgical training, object detection, YOLOv8, residency