The study, published in BMC Cancer by a team led by Zhibin Fu, Linhui Wang, and Jiazi Shi from the Naval Medical University hospitals in Shanghai, set out to answer a deceptively simple question: what is the long-term trajectory of renal parenchymal volume, the functional meat of the kidney, after tumor removal, and how does that trajectory relate to overall kidney function? To find out, the team sifted through the records of 1,947 patients who underwent laparoscopic or robot-assisted partial nephrectomy for renal tumors between January 2015 and December 2021. From that pool, 149 patients with confirmed renal cell carcinoma and complete serial imaging plus clinical follow-up made it into the final analysis.

The technical centerpiece of the work is three-dimensional CT volumetry. Rather than relying on the crude proxy of kidney length or the blunt instrument of a single blood test, the researchers measured the actual volume of functioning renal tissue on each side of the body at three time points: before surgery, at a first postoperative follow-up between one and six months, and at a last follow-up at least 36 months after the operation. Using contrast-enhanced CT images reconstructed at one-millimeter slice thickness, they employed a semi-automated segmentation workflow with an edge-snapping magnetic-lasso tool, manually corrected the contours, and verified them on coronal and sagittal reformations before letting the software calculate three-dimensional volumes. Kidney function was tracked in parallel using the estimated glomerular filtration rate, or eGFR, calculated with the CKD-EPI equation, the standard formula used to stage chronic kidney disease.

The numbers tell a clear story of slow attrition. The ipsilateral kidney, the one that was operated on, started at a median parenchymal volume of 172.57 cubic centimeters before surgery. By the first follow-up visit, a median of 2.8 months after the operation, it had already fallen to 156.66 cubic centimeters, reflecting the immediate loss of tissue removed with the tumor along with early postoperative changes. But the shrinkage did not stop there. At the last follow-up, the volume had dropped further to 136.04 cubic centimeters, which works out to an annualized decline of 3.00 percent during the late follow-up period. In other words, the operated kidney kept losing functional tissue year after year, long after the surgical wound had healed.

Perhaps the most striking finding concerns the contralateral kidney, the untouched organ on the other side of the body. Conventional wisdom holds that when one kidney loses capacity, the other hypertrophies to pick up the slack, a phenomenon well documented after living kidney donation and radical nephrectomy. Yet in this cohort, the healthy kidney barely changed: 175.02 cubic centimeters before surgery, 179.92 cubic centimeters at the first follow-up, and 178.80 cubic centimeters at the last. The researchers found no significant evidence of compensatory hypertrophy. Total parenchymal volume across both kidneys declined at an annualized rate of 1.08 percent, and eGFR declined at 0.65 percent per year, with wide interquartile ranges indicating that some patients fared considerably worse than others.

To understand why some kidneys atrophy faster than others, the team ran univariate and multivariate linear regression models covering demographics, comorbidities, tumor characteristics, and surgical parameters. Three factors emerged as independently associated with the annualized rate of ipsilateral volume loss. Tumor composition mattered: patients with cystic tumors, which are fluid-filled and often require less parenchymal resection, showed different atrophy rates than those with solid tumors, with a p-value of 0.028. Surgical method also played a role, with robot-assisted procedures differing from laparoscopic ones at p equal to 0.048, a result that will feed the ongoing debate over whether the robot’s enhanced dexterity and finer suturing translate into better long-term organ preservation. Finally, ischemia type was associated with volume loss at p equal to 0.023, comparing patients whose renal blood flow was not temporarily clamped with those who underwent warm ischemia, the period during which the kidney is deliberately starved of blood while the surgeon reconstructs it.

Intriguingly, no independent predictors were identified for the annualized change rates of the contralateral kidney, total parenchymal volume, or eGFR. The healthy kidney’s behavior and the overall functional decline appear to follow their own course, resistant to the clinical variables the team tested. When the researchers instead looked at the absolute values at the last follow-up, a different set of relationships surfaced. Final total parenchymal volume was independently associated with patient age and preoperative volume measurements, while final eGFR was independently predicted by age, preoperative contralateral volume, and preoperative eGFR. The practical implication is sobering but useful: the best predictor of how a patient’s kidneys will function years after surgery is largely written into the patient before the first incision is made.

The disconnect between volume and function deserves attention. A three percent annual loss of ipsilateral tissue did not translate into a proportionally steep eGFR decline, likely because the global filtration rate blends contributions from both kidneys and because the relationship between parenchymal mass and filtration capacity is nonlinear. This is precisely where the authors argue CT volumetry earns its place. By measuring each kidney separately, volumetry offers a window into split renal function that serum creatinine and eGFR cannot provide. A stable eGFR can mask progressive atrophy on the operated side that only becomes clinically meaningful if the other kidney later falters, a scenario relevant to patients at risk of chronic kidney disease from diabetes, hypertension, or future contralateral tumors.

The study’s design carries caveats worth noting. It was a retrospective cohort approved by the Institutional Review Board of Changzheng Hospital and conducted under the Declaration of Helsinki, drawing on patients who happened to have complete serial imaging, which may introduce selection bias toward healthier or more closely monitored individuals. The ischemia finding, the authors note, is exploratory after adjustment. The median follow-up of 47.4 months, with an interquartile range of 36.0 to 60.4 months, is long by surgical oncology standards but still may not capture atrophy trajectories over decades. Funding came from the National Natural Science Foundation of China and the Changfeng Talent Development Program, and the authors declared no competing interests.

Even with those limitations, the message for patients and clinicians is actionable. Partial nephrectomy remains the standard of care for localized renal cell carcinoma precisely because it spares tissue and protects long-term kidney function compared with radical removal of the whole organ. This study does not challenge that standard; it refines the follow-up playbook. The operated kidney is not a finished structure once the tumor is out. It is a slowly remodeling organ whose parenchyma continues to atrophy at a measurable, predictable clip, and the opposite kidney, contrary to textbook expectations, does not reliably enlarge to compensate. The authors recommend integrating CT-based volumetric assessment into long-term postoperative surveillance, so that creeping volume loss can be detected and weighed against blood-based function measures before it becomes a clinical problem. For the growing population of kidney cancer survivors living decades after surgery, that shift from snapshot monitoring to longitudinal volumetric tracking could prove one of the quieter but more consequential legacies of this research.

Subject of Research: Long-term changes in renal parenchymal volume and kidney function after minimally invasive partial nephrectomy for renal cell carcinoma

Article Title: Changes in renal parenchymal volume and renal function after minimally invasive partial nephrectomy for renal cell carcinoma at median 47.4-month follow-up

Article References: Fu, Z., Wen, Q., Wu, C., Chen, F., Ni, J., Wang, J., Wang, J., Zhang, Z., Chen, M., Wu, Z., Wang, L., & Shi, J. (2026). Changes in renal parenchymal volume and renal function after minimally invasive partial nephrectomy for renal cell carcinoma at median 47.4-month follow-up. BMC Cancer. https://doi.org/10.1186/s12885-026-16996-y

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16996-y

Keywords: renal cell carcinoma, partial nephrectomy, renal parenchymal volume, eGFR, CT volumetry, kidney function, warm ischemia, robot-assisted surgery, laparoscopy, chronic kidney disease, surgical oncology, nephrology

The study, published in Global Surgical Education, the journal of the Association for Surgical Education, enrolled 48 medical students who had completed a course in operative technique and experimental surgery. Every participant was a genuine laparoscopic novice: none had undertaken formal simulation training, practiced on the study platform, or received structured instruction in laparoscopic suturing before the experiment. This naive cohort was a deliberate choice. By testing learners before they could compensate for lost depth cues with experience, the investigators could isolate the pure effect of visualization modality on early skill acquisition, the phase of training where the cognitive burden of learning instrument handling, camera interpretation, and task sequencing is heaviest.

The trial used a randomized cross-over design to control for the wide individual variability that plagues surgical skills research. Participants were allocated one-to-one to two sequences. One group performed four standardized laparoscopic tasks first under two-dimensional high-definition visualization and then repeated them under three-dimensional high-definition vision; the other group followed the reverse order. Because the intervention was a visual display, blinding of participants and investigators was impossible, but the cross-over structure allowed each student to serve as their own control. Task completion time in seconds and the number of predefined errors served as the primary objective outcomes, while a study-specific post-task questionnaire captured perceived depth perception, performance, speed, visual adaptation, and adverse symptoms.

The four tasks were calibrated to test progressively demanding psychomotor skills on a physical box trainer using real graspers and needle holders. Task one required positioning ten metal cylinders at predefined locations on a board, with an error counted for any misplaced cylinder. Task two involved transferring ten pearls, one at a time, from a container with a 42-millimeter opening into one with a tighter 35-millimeter opening. Task three demanded that participants grasp a disposable needle and its cap from the bottom of the box and cap the needle above the floor, with punctures and dropped objects counted as errors. Task four, the most complex, tested suturing and knot tying on a sponge model with 3-0 nylon on a CTI 3/8 circle needle, timed from the first stitch through the third knot.

The results were striking, particularly among students who moved from two-dimensional to three-dimensional visualization. In this sequence, three-dimensional vision produced statistically significant improvements in every single task. Cylinder positioning was completed 32.9 percent faster with 40.8 percent fewer errors. Pearl transfer was 24.6 percent faster with errors reduced by 67.6 percent. Needle capping improved by 38.5 percent in time and 32.6 percent in errors, while knots and suturing were 22.3 percent faster with 29.4 percent fewer errors. All comparisons reached statistical significance, with p values at or below 0.002 for the time outcomes and p less than 0.001 for error counts.

The reverse sequence, in which students began with three-dimensional vision and switched to two-dimensional, told a subtler story, as expected when learning from task repetition can mask the benefit of a second modality. Here, three-dimensional visualization still produced 50 percent fewer errors in pearl transfer and a 27.4 percent faster completion of needle capping with 27 percent fewer errors, both statistically significant, though some differences narrowed or lost significance. To address carryover learning directly, the investigators compared initial performance between the two groups, contrasting students who had never seen the tasks with those starting on three-dimensional vision. This first-exposure comparison favored 3D in three of the four tasks, including a 21.7 percent faster cylinder positioning with 38.8 percent fewer errors and a dramatic 50.4 percent faster needle capping with 36.9 percent fewer errors, strengthening the case that stereopsis confers a genuine advantage rather than a mere order effect.

The subjective data reinforced the objective measurements with remarkable consistency. An overwhelming 97.9 percent of participants reported better depth perception with three-dimensional vision, 79.2 percent reported better performance and more accurate gestures, and 85.4 percent reported faster task execution. A slimmer majority, 52.1 percent, found the three-dimensional display easier to adapt to, and 47.9 percent actually considered the two-dimensional image more natural, a finding the authors attribute to limited prior exposure to stereoscopic displays, variation in individual tolerance to 3D imaging, monitor positioning, and discomfort related to the glasses. Adverse symptoms were modest but real: 33.3 percent reported discomfort or hand pain during instrument manipulation, 25 percent reported blurred vision, and 8.3 percent reported dizziness, while one-third of participants experienced no symptoms at all.

The technical significance of the study lies less in the individual percentages than in the platform itself. The authors intentionally excluded virtual reality, augmented reality, and force-feedback haptics so that the experiment would isolate the effect of stereoscopic visualization while preserving the tactile interaction of real instruments within a physical trainer. The configuration combined a Sony HDR-TD20 camera capable of both 2D and 3D high-definition recording, an HDMI cable, a Samsung LED TD950 2D/3D monitor, and a standard laparoscopic box trainer with conventional graspers and needle holders. Commercial 3D laparoscopic towers and robotic platforms remain prohibitively expensive for many training programs, and the authors situate their work within a broader movement toward affordable simulation, citing recent examples including biodegradable 3D-printed simulators, validated low-cost trainers, and automated error-detection systems that improve trainee confidence.

The findings also engage with ongoing debates about validity in surgical education. The authors are careful to note that their simulator should not be described as valid in isolation; rather, the completion times, error counts, and preference responses constitute context-specific evidence about immediate simulator performance among novices. They also acknowledge a caution raised in prior literature that two-dimensional versus three-dimensional comparisons vary widely in task type, participant experience, endpoints, and subjective assessment. Among the study’s stated limitations are its exclusive novice population, the short interval between modalities that may have permitted carryover learning, the absence of delayed retention testing or transfer to clinical performance, and a study-specific questionnaire that was not formally psychometrically validated. Baseline measures of video-game use and other visuospatial experience were also not collected.

Nevertheless, the message for global surgical education is clear and potentially transformative. Where access to robotic simulators, high-fidelity virtual reality trainers, or commercial 3D towers is limited by capital and maintenance costs, a low-cost stereoscopic trainer may allow students and residents to acquire fundamental visuospatial and psychomotor skills before entering the operating room. The authors position such platforms not as replacements for emerging autostereoscopic and augmented-reality systems, which may eventually combine depth perception with image-guided overlays and remote instruction, but as a pragmatic bridge until those technologies become widely accessible. Future studies, they suggest, should include delayed retention testing, transfer tasks, clinical outcome measures, and baseline visuospatial profiling. If replicated, the demonstration that a few hundred dollars of consumer hardware can outperform flat high-definition vision on every measure that matters in early laparoscopic training could help democratize surgical skills education in precisely the settings where trained surgeons are scarcest.

Subject of Research: Three-dimensional versus two-dimensional visualization in low-cost laparoscopic skills training for novices

Article Title: 3-Dimensional versus 2-dimensional visualization on laparoscopic skills training in a low-cost simulation model: a randomized cross-over trial

Article References: Heldwein, F. L., Freire, E. S., Vicente, M. V. S., Porath, H., & Veiga, C. B. (2026). 3-Dimensional versus 2-dimensional visualization on laparoscopic skills training in a low-cost simulation model: a randomized cross-over trial. Global Surgical Education – Journal of the Association for Surgical Education, 5(1), Article 164. https://doi.org/10.1007/s44186-026-00567-7

Image Credits: AI Generated

DOI: 10.1007/s44186-026-00567-7

Keywords: laparoscopy, simulation training, 3D visualization, 2D visualization, stereopsis, depth perception, surgical education, box trainer, randomized cross-over trial, low-cost simulator, novice trainees, psychomotor skills