Glasses-free three-dimensional laparoscopic systems in oncologic surgery: Innovation or equivalence?

Abstract

The development of minimally invasive surgery has transformed the management of gastrointestinal cancer. Notably, three-dimensional visualization systems have increased surgical precision. This editorial discusses a recent study by Shen and Zhang, which compared the clinical applications of naked-eye three-dimensional laparoscopic systems vs traditional optical systems in radical surgery for gastric and colorectal cancer. Both systems appeared to yield comparable surgical and oncological outcomes in terms of safety parameters, operating times, and quality of lymph node dissection. However, the spectacle-free system’s technical and logistical limitations hindered its effects on the surgical team’s overall competency. This editorial examines the authors’ findings within the broader context of the evolution of oncologic laparoscopy, discusses the relevance of the results in light of the current literature, and proposes future research directions focused on multicenter validation, comprehensive ergonomic analysis, and technological advancements aimed at enhancing intraoperative collaboration. As technology continues to evolve, clinical implementation of new methods must be supported by robust scientific evidence and standardized criteria, to ensure tangible improvements in efficiency, safety, and oncologic outcomes.

Key Words: Autostereoscopic three-dimensional technology; Laparoscopic surgery; Three-dimensional laparoscopy; Two-dimensional laparoscopy; Oncologic surgery

Core Tip: The glasses-free three-dimensional laparoscopic system is an innovative alternative to the conventional glasses-based systems used in gastrointestinal oncologic surgery. Although preliminary findings suggest its comparable clinical efficacy to conventional systems, its widespread clinical use still faces several technical, ergonomic, and logistical challenges. Future research should evaluate not only surgical outcomes but also the effects on intraoperative collaboration, surgeon perception, and user experience.

INTRODUCTION

In the evolution of minimally invasive surgery, which has transformed the approach to gastrointestinal cancer, the roles of three-dimensional (3D) visualization systems in optimizing surgical precision have been notable[1-4]. In the 1990s, advances in 3D laparoscopic systems, which previously relied on the use of polarized glasses, markedly improved spatial orientation, depth perception, and operative ergonomics, particularly in complex approaches. These developments have facilitated more effective and safer interventions in abdominal oncologic surgery[5,6].

Within this framework, new autostereoscopic 3D laparoscopic systems, referred to as glasses-free or “naked-eye” 3D systems, have been aimed at overcoming the limitations of traditional systems, such as equipment discomfort, eye fatigue, and visualization difficulties among surgical team members. A retrospective study by Shen and Zhang[7], published in the World Journal of Gastrointestinal Surgery, has analyzed the efficacy of these glasses-free systems, compared with conventional 3D systems, in gastric and colorectal cancer surgery. Although similar results were found between techniques, this apparent equivalence prompts critical reflection on whether these new systems are as safe as conventional systems and whether they provide added value. Previous studies have indicated that 3D systems, with or without glasses, can enhance surgical performance, particularly among surgeons with limited experience[8,9]. However, glasses-free systems still pose several technical challenges, such as lower resolution, limited viewing angles, and difficulty in effectively integrating the entire surgical team. Consequently, this editorial analyzes whether this method provides a genuine advance or an equivalent technical alternative. On the basis of the available literature, the limitations, benefits, and future prospects of glasses-free 3D laparoscopy in gastrointestinal oncologic surgery are discussed.

LAPAROSCOPIC SYSTEMS IN GASTROINTESTINAL CANCER SURGERY

Gastrointestinal surgery has been revolutionized by laparoscopy, which minimizes surgical invasiveness by making small incisions, thereby offering benefits such as decreasing postoperative pain, shortening hospital stays, and enabling faster return to daily activities[1,2]. However, in traditional laparoscopy using two-dimensional (2D) visualization, a major challenge is the loss of depth perception. This limitation increases cognitive demand and contributes to fatigue among surgeons performing complex maneuvers in a 3D environment projected onto a flat screen[1-4].

Given these limitations, 3D visualization systems were developed to reproduce the natural stereopsis of the human eye by using dual camera or stereoscopic technologies. This approach enables more accurate spatial perception of anatomical structures, and increases hand-eye coordination, operative speed, and surgical safety, particularly in procedures requiring intracorporeal suturing or fine dissection[1,2]. The integration of 3D visualization marked a paradigm shift providing realistic depth perception in real time[1,8]. The 3D systems enable significantly greater performance of both basic and advanced surgical tasks than 2D systems, particularly among surgeons with limited experience. The main measurable clinical findings for these systems, as compared with 2D systems, include their markedly faster operative times, less intraoperative blood loss, and shorter lengths of hospital stay[9]. Although early 3D prototypes had technical drawbacks, such as a need for active or polarized glasses that caused discomfort and adverse effects such as dizziness, nausea, and visual fatigue, recent advancements have improved the ergonomics, resolution, and compatibility with minimally invasive techniques[1,8].

The advanced optical technologies of 3D laparoscopic systems without glasses enable perception of 3D depth without use of glasses. These innovative systems rely on two primary mechanisms to direct various images to each eye of the operator: The parallax barrier and the lenticular lens[10,11]. The parallax barrier is based on a grid that is placed in front of the screen and selectively blocks certain parts of the image for each eye, thus creating a sense of depth. In contrast, the lenticular lens, through a series of cylindrical micro-lenses, refracts light in specific directions, thereby assigning a different visual channel for each eye. The more advanced systems that are currently available integrate eye-tracking technology enabling identification of the user’s position and real-time adjustment of image projection, and preservation of stereoscopic effects even when the operator moves within a certain range. These innovative systems enable operators to perceive realistic 3D images without a need for glasses, although their effectiveness is currently optimized primarily for a single operator on the central axis, thus limiting intraoperative collaborative work[10,11].

The retrospective study by Shen and Zhang[7] is among the first retrospective clinical investigations comparing the implementation of a glasses-free 3D system in radical surgeries for gastric and colorectal cancer (n = 16) vs conventional 3D technology with polarized glasses (n = 52). Importantly, the study advances beyond prior studies focused on simulators or experimental interventions, by analyzing the use of these methods in real clinical practice in patients with cancer[7]. No significant differences were found between the glasses-free (n = 16) and glasses-wearing (n = 52) 3D system groups in terms of operative time (195 minutes vs 196 minutes), blood loss (20 mL vs 40 mL), and complication rates (12.5% vs 17.3%). Therefore, the glasses-free system might be considered to have equivalent efficacy and safety in terms of immediate clinical outcomes. However, the findings should be interpreted with caution, because of various methodological limitations. First, the study’s small sample size in the intervention group (n = 35) restricted the generalizability of the results and the statistical power. Additionally, the surgical interventions were performed by a single surgeon, thus posing potential operative bias and restricting the analysis of interoperative variability - a particularly important aspect for technologies aimed at improving surgical performance. Likewise, whether multivariate adjustments were made to control for possible confounding factors, such as tumor stage, comorbidities, or procedure type, is unknown. Second, despite the adequate definition of the inclusion and exclusion criteria, the authors limited their evaluation to a particular subgroup of patients with gastric or colorectal tumors, thereby restricting the applicability of the findings to other surgical contexts. Third, although the researchers determined that both systems presented “comparable” findings, they considered only immediate surgical outcomes but not functional variables, such as visual fatigue, cognitive load, or surgical equipment performance, which are essential factors for the introduction of new technologies. Consequently, these methodological restrictions must be considered in interpreting the apparent equivalence identified between both systems and highlight the need for prospective randomized studies including ergonomic, clinical, and intraoperative performance parameters.

Considering these findings alongside other studies reveals interesting nuances (Table 1). A prospective study by Agrusa et al[12] examined various complex surgical procedures in 163 patients undergoing 3D high-definition laparoscopic surgery compared with a retrospective-prospective 2D control group. The 3D system was found to improve surgical precision, the definition of anatomical planes, and depth perception (P < 0.05), as well as to significantly shorten surgical times for complex interventions (P < 0.05), such as anti-reflux surgery, esophageal myotomy, colorectal resections, and sacrocolpopexy. Regarding complications and bleeding, despite an absence of statistically significant differences between groups, two esophageal perforations occurred in the 2D group, whereas none occurred in the 3D group. In contrast, Busshoff et al[8] in a prospective trial, have demonstrated that the 3D system improves the performance of novice surgeons in simulated laparoscopic tasks, thus highlighting its value as a teaching tool. The improvement was significantly greater in female (27.84% times decrease) than male (25.31% times decrease; P = 0.005) operators. This investigation was the first to evaluate the application of the 3D system through a sex-based approach. Among medical students, women showed a greater time decrease (327.6 seconds) than men (249.8 seconds) (P = 0.041). However, no significant differences by sex were observed among certified surgeons; this finding suggested a diminishing performance gap between sexes with increasing experience. Notably, because no studies have rigorously analyzed the implementation of glasses-free systems, the article by Shen and Zhang[7] provides a fundamental, albeit preliminary, first step.

Table 1 Comparison of studies on three-dimensional laparoscopic surgery in gastrointestinal cancer.

Ref.	Objective	Study type	Population	Technology evaluated	Surgeons	Main outcomes	Statistical significance	Functional evaluation
Shen and Zhang[7], 2025	Compare glasses-free 3D laparoscopy with glasses-based 3D laparoscopy in radical gastrointestinal surgery	Retrospective, comparative	165 patients (99 males, 66 females) with gastric or colorectal cancer	Glasses-free 3D (autostereoscopic) vs glasses-based 3D	All procedures were performed by a single surgeon	No significant differences in operative time, blood loss, or complication rates	Significant differences favoring glasses-based 3D in multiple clinical parameters (P < 0.05)	Quality of life, pain, and functional recovery (6-minute walk) were analyzed
Agrusa et al[12], 2018	Analyze the clinical benefits of 3D vs 2D laparoscopy in various complex procedures	Prospective (3D) vs retrospective-prospective control group (2D)	163 patients (74 males, 89 females) with various surgical indications	3D high-definition laparoscopy vs 2D high-definition laparoscopy	All procedures were performed by the same surgical team	3D reduced operative time in complex procedures; no differences in blood loss or complications	3D showed significant benefits in complex surgeries (P < 0.05); not in simple procedures	Subjective performance (accuracy, depth perception, visual fatigue) was assessed
Busshoff et al[8], 2022	Evaluate surgical performance differences between men and women using 3D vs 2D-ultra-high definition imaging	Randomized crossover trial	28 participants (56 females, 72 males), including students and certified/non-certified surgeons	Passive 3D vs 2D in ultra-high definition resolution	Surgeons and students with varying levels of experience	3D significantly reduced total time and number of errors; greater benefits observed in women and less experienced surgeons	3D showed significant differences in time and errors (P < 0.001)	Performance (time, errors) as well as fatigue and surgical interest were analyzed

3D: Three-dimensional; 2D: Two-dimensional.

Despite their evolution, glasses-free 3D systems still face substantial challenges, such as the need for precise operator positioning in front of the screen to maintain the 3D effect, dependence on optimal lighting conditions, and a limited shared viewing angle[5]. The viewing angle is particularly crucial in team dynamics, to avoid impeding collaboration and coordination between surgeons and assistants. This issue is critical in complex oncological surgeries, in which precise synchronization of dissection, aspiration, and retrograde assistance are essential. In contrast, glasses-based 3D systems, compared with 2D systems, enable substantially greater hand-eye coordination and depth perception, and less mental fatigue for the primary operator, particularly during operative tasks such as fine dissection and intracorporeal suturing[7]. These findings suggest that the benefits of 3D vision are well established in conventional glasses-based systems. Therefore, the primary challenge for new systems is not merely replicating safety but demonstrating superiority in terms of surgeon performance, operating costs, learning curves, and team collaboration. This evidence gap should be addressed in future research.

One of the most important challenges of glasses-free 3D systems is the limited effective viewing angle, which must be maintained within a specific range on the screen to preserve the stereoscopic effect[5,13]. This visual limitation can complicate coordination among surgical team members, particularly in interventions requiring high synchronization among surgeons, assistants, and instrumentists. Whereas systems with glasses provide an individualized 3D visual experience to each participant in the team, glasses-free 3D systems restrict 3D perception to a specific visualization site and consequently prevent peripherally located assistants from experiencing the 3D effect[13]. In clinical contexts, such as during lymphadenectomy in gastric surgery or before deep pelvic dissection in colorectal surgery, precision in tissue management and the coordination of tweezers or the vacuum cleaner by the assistant are fundamental. If the assistant does not visualize the same 3D visual field, the precise identification of anatomical planes is compromised, delays may occur in critical maneuvers, or uncoordinated movements may occur and subsequently influence the quality of the intervention. These restrictions can increase primary surgeons’ cognitive load as they try to compensate for their team members’ visual limitations. Consequently, the fixed angle of vision challenge is not exclusively technical but has direct clinical implications in the quality, coordination, and precision of complex laparoscopic interventions. Considering this challenge in future technological versions of the system will be essential to achieving the complete integration of the surgical team in minimally invasive environments[13,14].

FUTURE PERSPECTIVES

The recent encouraging findings regarding the glasses-free 3D laparoscopic system indicate that this technological innovation has potential not only to preserve the advantages of stereoscopic vision but also to overcome certain logistical and ergonomic limitations of conventional systems. However, to allow for widespread clinical implementation of glasses-free 3D systems, a structured research agenda with several key lines of action must first be established.

Given that the study by Shen and Zhang[7] was retrospective, involved a limited sample size, and was conducted at a single center, multicenter randomized trials are needed to directly compare traditional systems (2D and 3D with glasses) with glasses-free 3D systems. To ensure rigorous, correct, and standardized evaluation of the ergonomic and cognitive effects of glasses-free 3D laparoscopic systems, future studies should consider objective evaluation tools such as electromyography, eye tracking, and integration of validated scales for analyzing cognitive workload. In the early stages of validation, these studies should be conducted within high-fidelity surgical simulations to control experimental variables, decrease clinical variability, and increase the replicability of the findings. In this context, complex surgical interventions (such as advanced lymphadenectomy, intracorporeal suture, or retroperitoneal dissection) should be prioritized, because they require high-level visuospatial coordination, fine motor skills, and sustained attention; these procedures are likely to reveal substantial ergonomic discrepancies among visualization systems.

Regarding workload evaluation, implementing validated scales such as the national aeronautics and space administration task load index and the surgery task load index is advised, to enable multidimensional assessments integrating temporal demand, mental demand, physical effort, frustration, and perceived performance. Considering these tools alongside data collected from electromyography and eye tracking (including pupillary changes, visual fixation patterns, or saccadic movements) would facilitate a comprehensive analysis of visual fatigue, muscle tension, and the distribution of attention throughout prolonged interventions. Furthermore, ongoing improvements in visual technology are necessary to refine the glasses-free system to achieve advances in image quality with higher-resolution displays, expansion of the effective field of view, and integration with augmented imaging techniques or 3D reconstruction. Finally, promoting institutional policies that support continuing training and education of surgical teams in emerging technologies will be critical. Incorporating 3D simulators into specialty training programs and conducting controlled clinical trials focused on various visual modalities would accelerate the scientific validation of these innovations. Consequently, continued objective evaluation of effects on the learning curve, particularly for surgeons in training, by using performance metrics and movement analysis, should be prioritized.

CONCLUSION

The introduction of glasses-free 3D laparoscopic systems represents a major technological innovation in gastrointestinal oncologic surgery. Although preliminary findings from Shen and Zhang[7] suggest these systems’ comparable efficacy and safety to those of traditional 3D systems using glasses, this apparent equivalence must be interpreted with caution. Current technical and logistical challenges limit the widespread clinical adoption of this new technology, particularly regarding intraoperative collaboration and surgical team ergonomics. Future research focusing on comprehensive evaluation of cognitive load, technical performance, and ergonomic benefits will be essential to support broader implementation. Ultimately, rigorous scientific validation will determine whether this innovation is truly revolutionary or is merely a comparable technical alternative.