Evolution of stereoscopic imaging in surgery and recent advances

Surgeon Preference and Clinical Outcome of 3D Vision Compared to 2D Vision in Laparoscopic Surgery: Systematic Review and Meta-Analysis of Randomized Trials

Objective

To assess the added value of 3-dimensional (3D) vision, including high definition (HD) technology, in laparoscopic surgery in terms of surgeon preference and clinical outcome.

Background

The use of 3D vision in laparoscopic surgery has been suggested to improve surgical performance. However, the added value of 3D vision remains unclear as a systematic review of randomized controlled trials (RCTs) comparing 3D vision including HD technology in laparoscopic surgery is currently lacking.

Methods

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines with a literature search up to May 2023 using PubMed and Embase (PROSPERO, CRD42021290426). We included RCTs comparing 3D versus 2-dimensional (2D) vision in laparoscopic surgery. The primary outcome was operative time. Meta-analyses were performed using the random effects model to estimate the pooled effect size expressed in standard mean difference (SMD) with corresponding 95% confidence intervals (CIs). The level of evidence and quality was assessed according to the Cochrane risk of bias tool.

Results

Overall, 25 RCTs with 3003 patients were included. Operative time was reduced by 3D vision (-8.0%; SMD, -0.22; 95% CI, -0.37 to -0.06; P = 0.007; n = 3003; 24 studies; I 2 = 75%) compared to 2D vision. This benefit was mostly seen in bariatric surgery (-16.3%; 95% CI, -1.28 to -0.21; P = 0.006; 2 studies; n = 58; I 2 = 0%) and general surgery (-6.7%; 95% CI, -0.34 to -0.01; P = 0.036; 9 studies; n = 1056; I 2 = 41%). Blood loss was nonsignificantly reduced by 3D vision (SMD, -0.33; 95% CI, -0.68 to 0.017; P = 0.060; n = 1830; I 2 = 92%). No differences in the rates of morbidity (14.9% vs 13.5%, P = 0.644), mortality (0% vs 0%), conversion (0.8% vs 0.9%, P = 0.898), and hospital stay (9.6 vs 10.5 days, P = 0.078) were found between 3D and 2D vision. In 15 RCTs that reported on surgeon preference, 13 (87%) reported that the majority of surgeons favored 3D vision.

Conclusions

Across 25 RCTs, this systematic review and meta-analysis demonstrated shorter operative time with 3D vision in laparoscopic surgery, without differences in other outcomes. The majority of surgeons participating in the RCTs reported in favor of 3D vision.

Comparison of 2D 4K vs. 3D HD laparoscopic imaging systems in bariatric surgery: study protocol for a randomized controlled prospective trial

BACKGROUND

Vision is an important and defining element of laparoscopy and significantly affects the outcome of surgery in terms of time, error, and precision. Several new imaging systems have become available for laparoscopic surgery, including three-dimensional (3D) high-definition (HD) and two-dimensional (2D) ultra-high-resolution (4K) monitors. 3D HD systems offer a number of potential benefits to surgeons and patients over traditional 2D systems, including reduced operating time, blood loss, and hospital stay. However, the performance of 3D systems against the new, ultra-high definition 4K systems is barely known and highly controversial. There is a paucity of studies comparing them in clinical settings. The aim of this study is to compare 2D 4K and 3D HD perspectives in gastric bypass surgery.

METHODS

Forty-eight patients with an indication for gastric bypass will be randomized to receive laparoscopic gastric bypass surgery using either 2D 4K or 3D HD systems. The operations will be performed by a well-coordinated team of three senior surgeons. The primary outcome is operative time. Secondary outcomes include intraoperative complications, blood loss, operator workload as assessed by the validated Surg-TLX questionnaire, and postoperative complications according to the Clavien-Dindo classification. An interim analysis is planned after enrollment of 12 participants for each group.

DISCUSSION

This prospective, randomized trial is designed to test the hypothesis that the use of a 3D HD system will result in a significant improvement in operative time compared to a 2D 4K system in bariatric surgery. The objective is to provide clinical evidence for new laparoscopic imaging systems and to evaluate potential benefits.

TRIAL REGISTRATION

This trial is registered at clinicaltrials.gov under the identifier NCT05895058. Registered 30 May 2023. BASEC2023-D0014 [Registry ID Swissethics, approved 3 May 2023]. SNCTP000005489 [SNCTP study register, last updated 13 July 2023].

Prospective randomized comparison of three-dimensional (3D) versus conventional laparoscopy in total colectomy for ulcerative colitis

BACKGROUND

3D laparoscopy has been proposed with the aim of improving the depth perception and overall operative performance. To aim of this study is to compare 3D laparoscopy with conventional 2D laparoscopy in terms of operative time and visual parameters.

METHODS

This is a prospective, randomized, single-center trial designed to determine 10% reduction in the mean operative time. Ulcerative colitis patients >18 years of age who underwent laparoscopic total abdominal colectomy with end ileostomy between 2015 and 2020 were included. Patients were randomized into 3D and 2D laparoscopy groups. Duration of operation and surgeons' evaluation of the visualization system were the primary outcomes.

RESULTS

Fifty-three subjects (26 in 2D, 27 in 3D group) were included in the analysis, with 56% being male. Mean age and body mass index were 40 (16.3) years and 23.5 (4.7) kg/m2 , respectively. Twenty-five subjects underwent single port laparoscopic surgery, of whom 13 were in 3D and 12 in 2D group. Mean operative time was 75.3 (30.8) versus 82.7 (38.6) minutes (P = 0.4) for 3D and 2D groups, respectively. Operative times spent for individual steps were comparable. Post-operative minor complications (8 in 3D versus 8 in 2D, P = 1) and median number of times for scope maintenance were also similar between the groups. 69% of the visual evaluation survey results favoured 3D over 2D (P = 0.014).

CONCLUSION

Three-dimensional laparoscopy for total colectomy in ulcerative colitis patients is safe and feasible option providing better visualization with no difference in operative time.

Effect of binocular disparity on learning anatomy with stereoscopic augmented reality visualization: A double center randomized controlled trial

Binocular disparity provides one of the important depth cues within stereoscopic three-dimensional (3D) visualization technology. However, there is limited research on its effect on learning within a 3D augmented reality (AR) environment. This study evaluated the effect of binocular disparity on the acquisition of anatomical knowledge and perceived cognitive load in relation to visual-spatial abilities. In a double-center randomized controlled trial, first-year (bio)medical undergraduates studied lower extremity anatomy in an interactive 3D AR environment either with a stereoscopic 3D view (n = 32) or monoscopic 3D view (n = 34). Visual-spatial abilities were tested with a mental rotation test. Anatomical knowledge was assessed by a validated 30-item written test and 30-item specimen test. Cognitive load was measured by the NASA-TLX questionnaire. Students in the stereoscopic 3D and monoscopic 3D groups performed equally well in terms of percentage correct answers (written test: 47.9 ± 15.8 vs. 49.1 ± 18.3; P = 0.635; specimen test: 43.0 ± 17.9 vs. 46.3 ± 15.1; P = 0.429), and perceived cognitive load scores (6.2 ± 1.0 vs. 6.2 ± 1.3; P = 0.992). Regardless of intervention, visual-spatial abilities were positively associated with the specimen test scores (η² = 0.13, P = 0.003), perceived representativeness of the anatomy test questions (P = 0.010) and subjective improvement in anatomy knowledge (P < 0.001). In conclusion, binocular disparity does not improve learning anatomy. Motion parallax should be considered as another important depth cue that contributes to depth perception during learning in a stereoscopic 3D AR environment.

Effect of 2D vs. 3D laparoscopy on postoperative complications and operation time in a propensity-score-matched real-world data analysis

BACKGROUND

Postoperative complication rates using 3D visualization are rarely reported. The primary aim of our study is to detect a possible advantage of using 3D on postoperative complication rates in a real-world setting.

METHOD

With a sample size calculation for a medium effect size difference that 3D reduces significantly postoperative complications, data of 287 patients with 3D visualization and 832 with 2D procedure were screened. The groups underwent an exact propensity score-matching to be comparable. Comprehensive complication index (CCI) for every procedure was calculated and Operation Time was determined.

RESULTS

Including 1078 patients in the study, 213 exact propensity score-matched pairs could finally be established. Concerning overall CCI (3D: 5.70 ± 13.63 vs. 2D: 3.37 ± 9.89; p = 0.076) and operation time (3D: 103.98 ± 93.26 min vs. 2D: 88.60 ±6 9.32 min; p = 0.2569) there was no significant difference between the groups.

CONCLUSION

Our study shows no advantage of 3D over 2D laparoscopy regarding postoperative complications in a real-world setting, the second endpoint operation time, too, was not influenced by 3D overall.

Study on Reconstruction and Feature Tracking of Silicone Heart 3D Surface

At present, feature-based 3D reconstruction and tracking technology is widely applied in the medical field. In minimally invasive surgery, the surgeon can achieve three-dimensional reconstruction through the images obtained by the endoscope in the human body, restore the three-dimensional scene of the area to be operated on, and track the motion of the soft tissue surface. This enables doctors to have a clearer understanding of the location depth of the surgical area, greatly reducing the negative impact of 2D image defects and ensuring smooth operation. In this study, firstly, the 3D coordinates of each feature point are calculated by using the parameters of the parallel binocular endoscope and the spatial geometric constraints. At the same time, the discrete feature points are divided into multiple triangles using the Delaunay triangulation method. Then, the 3D coordinates of feature points and the division results of each triangle are combined to complete the 3D surface reconstruction. Combined with the feature matching method based on convolutional neural network, feature tracking is realized by calculating the three-dimensional coordinate changes of the same feature point in different frames. Finally, experiments are carried out on the endoscope image to complete the 3D surface reconstruction and feature tracking.

Robotic Surgery: Advancements and Inflection Points in the Field of Gynecology

Robotics has become an essential part of the surgical armamentarium for a growing number of surgeons around the world. New companies seek to compete with established robotic systems that have dominated the market to date. Evolving robotic surgery platforms have introduced technologic and design advancements to optimize ergonomics, improve visualization, provide haptic feedback, and make systems smaller and cheaper. With the introduction of any new technology in the operating room, it is imperative that safeguards be in place to ensure its appropriate use. Current processes for granting of hospital robotic surgery privileges are inadequate and must be strengthened and standardized.

Comparison of 2D 4K vs. 3D HD laparoscopic imaging systems using a pelvitrainer model: a randomized controlled study

Laparoscopic surgery provides well-known benefits, but it has technological limitations. Depth perception is particularly crucial, with three-dimensional (3D) imaging being superior to two-dimensional (2D) HD imaging. However, with the introduction of 4K resolution monitors, 2D rendering is capable of providing higher-quality visuals. Therefore, this study aimed to compare 3D HD and 2D 4K imaging using a pelvitrainer model. Eight experts and 32 medical students were performing the same four standardized tasks using 2D 4K and 3D HD imaging systems. Task completion time and the number of errors made were recorded. The Wilcoxon test and mixed-effects models were used to analyze the results. Students were significantly faster in all four tasks when using the 3D HD perspective. The median difference ranged from 18 s in task 3 (P < 0.003) up to 177.5 s in task 4 (P < 0.001). With the exception of task 4, students demonstrated significantly fewer errors in all tasks involving 3D HD imaging. The experts’ results confirmed these findings, as they were also faster in all four tasks using 3D HD, which was significant for task 1 (P < 0.001) and task 4 (P < 0.006). The expert group also achieved better movement accuracy using the 3D HD system, with fewer mistakes made in all four tasks, which was significant in task 4 (P < 0.001). Participants in both groups achieved better results with the 3D HD imaging system than with the 2D 4K system. The 3D HD image system should be used when available. Trial registration: this trial is registered at research registry under the identifier researchregistry6852.

4K versus 3D total laparoscopic hysterectomy by resident in training: a prospective randomised trial

Background

The introduction of ultra-high-definition laparoscopic cameras (4K), by providing stronger monocular depth perception, could challenge the existing 3D technology. There are few available studies on this topic, especially in gynaecological setting.

Objectives

Prospective, single institution, randomised clinical trial (NCT04209036).

Materials and Methods

The two laparoscopes utilised were the 0°ULTRA Telescopes with 4K technology and the 0°3D-HD by Olympus. The surgeons were all trainees and in their last year of residency and who had obtained the certificate of first or second level of the Gynaecological Endoscopic Surgical Education and Assessment program - GESEA program. Twenty-nine patients with benign uterine pathology were enrolled.

Main outcome measures

To compare if the use three-dimensional (3D) versus ultra-high-definition laparoscopic vision system (4K) for total laparoscopic hysterectomy performed by trainees was associated with a shorter operative time.

Results

The 3D vision system did not prove to be superior to the 4K vision system. Operators reported significantly more vision-related side effects when using 3D than 4K. Completing the GESEA training program was the only factor with a positive and statistically significant impact on the overall time of the procedure, especially when greater dexterity and tissue handling were required.

Conclusions

Neither technology used proved superior to the other, although operators showed a preference for 4K over 3D due to the lower number of visual side effects. Attendance at courses on laparoscopic simulators and training programs allowed trainees to demonstrate excellent surgical skills.

Comparison of 3D vs 2D laparoscopic-assisted anorectal pull-through (LAARP) for high anorectal malformations in children

INTRODUCTION

The limitation of two-dimensional (2D) laparoscopic techniques includes lack of stereoscopic vision and depth perception which can affect surgical performance, physical and mental comfort of the operating surgeon. 3D laparoscopic surgery is popular in adults; however, its application and experience in the pediatric age group have been limited. We did a comparison of 2D and 3D laparoscopic-assisted anorectal pull-through (LAARP) in male high anorectal malformations (ARM).

MATERIAL AND METHOD

This prospective cohort study included male children diagnosed with high anorectal malformation (recto-prostatic urethral fistula) who underwent LAARP in infancy after a neonatal colostomy between November 2019 to March 2020. The patients were randomized into a 2D group or 3D group at a 1:1 ratio. Patient demographics and operative/postoperative parameters were recorded. The effect of 3D laparoscopy was assessed in terms of laparoscopy visual parameters (image quality, depth perception, hand-eye coordination, and precision), physical discomfort (5-point Likert scale), and mental strain (State-Trait Anxiety Inventory scale). The statistical tests were performed on SPSS version 16.

RESULTS

The demographics of both groups, 20 (patients in each), were similar. There was a significant reduction of laparoscopy execution time, physical discomfort (for eye, hand and wrist strain), and overall mental strain in the 3D group. There were similar complications, blood loss, and hospital stay, and no open conversion in two groups.

CONCLUSION

3D LAARP is feasible and safe in the surgical treatment of ARM in children. Further studies with assessment by more than one observer are needed to investigate the wider application of 3D in pediatric surgery.

A randomized controlled trial of three-dimensional versus two-dimensional imaging system on duration of surgery and mental workload for laparoscopic gastropexies in dogs

OBJECTIVE

To evaluate the effect of three-dimensional (3D) laparoscopy compared to two-dimensional (2D) laparoscopy when evaluating duration of surgery for canine intracorporeally sutured gastropexy.

STUDY DESIGN

Randomized controlled clinical trial.

ANIMALS

Thirty client-owned dogs.

METHODS

Dogs were randomized into 2D or 3D groups and underwent a three-port laparoscopic intracorporeally sutured incisional gastropexy with barbed suture. Procedures were performed by a single board-certified surgeon. Duration of surgery was recorded and workload was assessed immediately after surgery using the NASA Task Load Index (TLX).

RESULTS

Median duration of surgery was 3 min shorter for 3D versus 2D (95%CI -10 to 13; p = .51). Surgical component durations, total and component TLX scores, and intraoperative complications also did not differ between groups. In a subgroup analysis excluding the first eight cases due to presumption of a learning curve with suturing technique, total TLX score (p = .004) and all component scores were lower for 3D as compared to 2D laparoscopy, although duration of surgery did not differ (p = .20).

CONCLUSION

The use of 3D laparoscopy was not associated with shorter duration of surgery when compared to 2D laparoscopy.

CLINICAL SIGNIFICANCE

3D laparoscopy requires further investigation in veterinary medicine to determine its utility in decreasing surgical duration, surgical complications or surgeon mental or physical workload.

Advances in Intraoperative Optics: A Brief Review of Current Exoscope Platforms

BACKGROUND

The advent of the operating microscope (OM) revolutionized the field of neurosurgery. It allowed surgeons to operate on and effectively treat diseases previously inaccessible with conventional eyesight because of magnification and illumination. Improvements in the essential methods of visualization and the quality of the optics have plateaued. Another main limitation of the OM remains its ergonomics because of the need of the surgeon and assistant to directly interface with the OM objective. Recently, exoscopes have been introduced to overcome some shortcomings of the conventional OM.

OBJECTIVE

To subjectively review the individual authors experience with the current exoscope platforms in an attempt to provide a resource to the neurosurgeon when considering imaging options.

METHODS

Experts with previous use of each individual platform were contacted and asked to contribute their experiences.

RESULTS

In total, 4 systems are discussed. They include the VITOM (Karl Storz, Tuttlingen, Germany), the Olympus ORBEYE (Olympus, Tokyo, Japan), the Synaptive Modus V (Synaptive Medical, Toronto, Canada), and the Zeiss KINEVO (Carl Zeiss AG, Oberkochen, Germany).

CONCLUSION

The advent of exoscopes has the potential to begin to allow surgeons to move beyond solely the microscope for intraoperative visualization while improving upon its ergonomic disadvantages.

Intraocular endoscopy: A review

Optimal visualization is one of the most challenging aspects of performing vitreoretinal surgery. In situations where conventional microscopic techniques provide poor posterior visualization, the adjunctive skill set of endoscopic visualization may be needed. This allows for by-passing the opaque anterior segment media and getting access to the posterior segment pathology. Endoscopic vitrectomy is a useful and unique adjunct to microincision vitreoretinal surgery. The optical set-up of endoscopy allows for clinical approaches that are impossible with regular microscope viewing systems. These include the ability to observe across optically significant anterior segment opacities and directly visualize the posterior segment of the eye. It also allows for visualizing the difficult-to-access retroirideal, retrolental, and anterior retinal structures. Surgical access to anatomic spaces like the pars plana, pars plicata, ciliary sulcus, ciliary body, and peripheral lens is tedious. This is made simpler by endoscopy. In this review, we summarize and review the usage of the intraocular endoscope as a diagnostic and therapeutic armamentarium across a wide spectrum of ocular pathologies.

Comparison of three-dimensional (3D) endovision system versus ultra-high-definition 4K endovision system in minimally invasive surgical procedures: a randomized-open label pilot study

BACKGROUND

Experimental work comparing 3-Dimensional (3D) and 4K ultra-high-definition endovision system (4K) indicates that the latter with double the resolution of standard 2D high-definition systems may provide additional visual cues to compensate for the lack of stereoscopic vision. There is paucity of studies comparing 3D and 4K system in clinical settings. This randomized study compares 3D and 4K systems in three laparoscopic procedures of increasing complexity.

METHODS

139 patients undergoing laparoscopic cholecystectomy (60 patients), transabdominal preperitoneal (TAPP) repair (49 patients) and laparoscopic Heller's cardiomyotomy with anti- reflux procedure (30 patients) between May 2018 and February 2020 were randomized to undergo surgery using either 3D or 4K systems. Primary objective was to measure total operative time. Secondary objectives were to compare workload perceived by surgeons using SURG-TLX and surgeon satisfaction score. Timings of key surgical steps and peri-operative course of the patients was also recorded. Data were analyzed using Stata Corp. 2015.

RESULTS

Patients undergoing surgery with 3D and 4K systems were comparable in their clinical and demographic profiles. The mean total operative time in 3D and 4K groups was comparable in cholecystectomy (52.7 vs 56.2, p = 0.50), TAPP (63.8 vs 69.6, p = 0.25) and Heller's cardiomyotomy (124.7 vs 143.3, p = 0.14) with faster hiatal dissection in 3D group (8 min, p = 0.02). Operative time was better in patients undergoing Heller's myotomy with Angle of His accentuation with 3D by 28 min (p = 0.03). Total workload was similar in 3D and 4K groups in all the procedures but mental & physical demand was lower in 3D group in Heller's cardiomyotomy (p = 0.03, p = 0.01), Surgeon satisfaction score was comparable in all three procedures.

CONCLUSION

Overall, 3D HD and 4K systems are comparable in performing laparoscopic cholecystectomy, TAPP and Heller's Cardiomyotomy. Hiatal dissection time, mental and physical task load was better with 3D in Heller's Cardiomyotomy.

Learning Laparoscopic Surgery Skills With a 4K Ultra-High Definition 2D vs a Three-Dimensional HD Laparoscopic System: Results From a Prospective Randomized Trial

Background. In minimally invasive surgery (MIS), the loss of stereoscopic depth perception in a two-dimensional (2D) representation is most challenging. Recently introduced 4K ultrahigh definition (UHD) 2D optical systems could potentially facilitate the learning and use of compensation mechanisms for the loss of depth perception. However, the role of the new 4K technology against three dimensional (3D) in learning and implementation of MIS remains unknown. The aim of this trial was to determine the influence of 4K UHD 2D vs 3D HD representation on the acquisition of MIS skills. Methods. This was a prospective randomized study involving 62 MIS-inexperienced study participants. We compared a laparoscopic 4K UHD 2D (system A) vs a laparoscopic 3D HD system (system B) for differences in learning MIS skills using the Lübeck Toolbox (LTB) video box trainer. We evaluated participants' performance regarding the repetitions required to reach the goal of each LTB task. Results. Comparing systems A and B, participants using the laparoscopic 3D system required fewer repetitions to achieve goals of LTB tasks No. 1 (P = .0048) and No. 3 (P = .0014). In contrast, for LTB tasks No. 2 and No. 4, no significant difference could be determined between both groups. Conclusion. Our results indicated that MIS basic skills can be learned quicker using a 3D HD system vs a 4K UHD 2D system. However, for MIS tasks in confined spaces, the learning speed with 4K UHD 2D imaging seems to be comparable to a 3D HD system.

The application of the three-dimensional high-definition laparoscope in thyroid microcarcinoma

BACKGROUND

This study aimed to evaluate the feasibility and safety of the three-dimensional (3D) high-definition (HD) laparoscope via a chest-breast approach in thyroid microcarcinoma.

METHODS

In this retrospective study, ten patients with thyroid microcarcinoma who underwent laparoscopic thyroidectomy in the Department of General Surgery of Tangdu Hospital from May 2016 to October 2016 were included. Preoperative thyroid and neck ultrasound in these patients showed a thyroid nodule ≤1 cm, and no significantly enlarged cervical lymph nodes were observed. The patients' thyroid function showed no subclinical hyperthyroidism. Three trocars were used via the chest and breast during the surgery. The main outcome measures included the operation time, intraoperative blood loss, postoperative hospital stay time, postoperative drainage volume, and the incidence of complications.

RESULTS

The ten patients were successfully treated using a 3D HD laparoscope. The mean operation time was 70-160 minutes, the average intraoperative blood loss was 10-30 mL, the mean postoperative hospital stay was 4.5 days, and the mean postoperative drainage volume was 10-20 mL. None of the patients needed to receive a traditional open thyroidectomy during the operation. No patient experienced hoarseness, numbness of limbs, or choking or coughing while drinking water.

CONCLUSIONS

The 3D endoscopic thyroidectomy operation via the chest-breast approach is a feasible and safe therapeutic method for the treatment of thyroid microcarcinoma.

Comprehensive review of surgical microscopes: technology development and medical applications

SIGNIFICANCE

Surgical microscopes provide adjustable magnification, bright illumination, and clear visualization of the surgical field and have been increasingly used in operating rooms. State-of-the-art surgical microscopes are integrated with various imaging modalities, such as optical coherence tomography (OCT), fluorescence imaging, and augmented reality (AR) for image-guided surgery.

AIM

This comprehensive review is based on the literature of over 500 papers that cover the technology development and applications of surgical microscopy over the past century. The aim of this review is threefold: (i) providing a comprehensive technical overview of surgical microscopes, (ii) providing critical references for microscope selection and system development, and (iii) providing an overview of various medical applications.

APPROACH

More than 500 references were collected and reviewed. A timeline of important milestones during the evolution of surgical microscope is provided in this study. An in-depth technical overview of the optical system, mechanical system, illumination, visualization, and integration with advanced imaging modalities is provided. Various medical applications of surgical microscopes in neurosurgery and spine surgery, ophthalmic surgery, ear-nose-throat (ENT) surgery, endodontics, and plastic and reconstructive surgery are described.

RESULTS

Surgical microscopy has been significantly advanced in the technical aspects of high-end optics, bright and shadow-free illumination, stable and flexible mechanical design, and versatile visualization. New imaging modalities, such as hyperspectral imaging, OCT, fluorescence imaging, photoacoustic microscopy, and laser speckle contrast imaging, are being integrated with surgical microscopes. Advanced visualization and AR are being added to surgical microscopes as new features that are changing clinical practices in the operating room.

CONCLUSIONS

The combination of new imaging technologies and surgical microscopy will enable surgeons to perform challenging procedures and improve surgical outcomes. With advanced visualization and improved ergonomics, the surgical microscope has become a powerful tool in neurosurgery, spinal, ENT, ophthalmic, plastic and reconstructive surgeries.

A laparoscopic study investigating 3D vs 2D imaging systems using a pelvitrainer model with experts, non-experts, and students

BACKGROUND

Vision is an essential element of laparoscopic surgery that defines the outcome of an operation in regards to time, mistakes and precision. A 3-dimensional (3D) perspective may improve vision during an operation. Therefore, this study was designed to compare 3D versus 2-dimensional (2D) perspectives using a pelvitrainer model.

METHODS

Fifty candidates were divided into 3 categories based on different experience levels. The candidates were randomised into two groups, with each group performing the same 4 standardised tasks. Group A approached the tasks first with 3D high definition and in a second turn with 2D high definition. Group B carried out the tasks with the systems in reverse order. Task completion time and the number of mistakes made for each task were recorded. After completing the tasks, participants answered questions concerning the two systems.

RESULTS

Group A was, on average, 20% faster at all four tasks and made approximately 18% fewer mistakes in two of the tasks in comparison to group B. The experts significantly benefited from the 3D system in terms of accuracy compared to non-experts and students. The students demonstrated a significantly greater benefit from the 3D system when performing non-linear, continuous movements. Loss of concentration occurred at the same rate for subjects using the 2D and 3D systems. Nausea and dizziness were reported only when working with the 3D system. 91% found the 3D system advantageous for accomplishing the tasks.

CONCLUSIONS

Irrespective of experience level, 3D laparoscopy shows advantages in saving time, increasing accuracy and reducing mistakes. These benefits were also accompanied by subjective advantages that were noted by the participants. However, the more complex the task, the less significant the benefit of the 3D system and some people feel handicapped by the eyewear.

Three-dimensional (3D) system versus two-dimensional (2D) system for laparoscopic resection of adrenal tumors: a case-control study

PURPOSE

Laparoscopy is the standard technique for resecting adrenal tumors worldwide. The main drawbacks of conventional 2D laparoscopy are limited depth perception and tactile feedback. Currently available high-quality 3D laparoscopy systems might improve surgical outcomes for adrenalectomy. We compare the safety and efficacy of 3D versus 2D laparoscopy in the treatment of adrenal tumors.

METHODS

This case-control study analyzed prospectively collected data from patients with benign or malignant adrenal tumors treated laparoscopically at a single academic medical center between April 2003 and March 2020. We collected demographic, diagnostic, preoperative, and operative variables, and used multiple linear and logistic regression to analyze differences in various short-term outcomes between the two approaches while adjusting for potential confounders.

RESULTS

We included 150 patients: 128 with benign tumors and 22 with malignant tumors; 95 treated with 3D laparoscopy (case group); and 55 with 2D laparoscopy (control group). After adjustment for patient, surgical, and tumor characteristics, a 2D vision was associated with a longer operative time (β = 0.26, p = 0.002) and greater blood loss (β = 0.20, p = 0.047). There was no significant difference in rates of conversion to open surgery (odds ratio [OR] = 1.47 (95% CI 0.90-22.31); p = 0.549) or complications (3.6% vs. 2.1%; p = 0.624).

CONCLUSIONS

With experienced surgeons, laparoscopic adrenalectomy was safer and more feasible with the 3D system than with the 2D system, resulting in less operative blood loss and shorter operative time with no differences in rates of conversion to open surgery or postoperative complications. For adrenal tumors, 3D laparoscopy offers advantages over 2D laparoscopy.

Learning curves, potential and speed in training of laparoscopic skills: a randomised comparative study in a box trainer

Background

The effectiveness of practical surgical training is characterised by an inherent learning curve. Decisive are individual initial starting capabilities, learning speed, ideal learning plateaus, and resulting learning potentials. The quantification of learning curves requires reproducible tasks with varied levels of difficulty. The hypothesis of this study is that the use of three-dimensional (3D) vision is more advantageous than two-dimensional vision (2D) for the learning curve in laparoscopic training.

Methods

Forty laparoscopy novices were recruited and randomised to a 2D Group and a 3D Group. A laparoscopy box trainer with two standardised tasks was used for training of surgical tasks. Task 1 was a positioning task, while Task 2 called for laparoscopic knotting as a more complex process. Each task was repeated at least ten times. Performance time and the number of predefined errors were recorded. 2D performance after 3D training was assessed in an additional final 2D cycle undertaken by the 3D Group.

Results

The calculated learning plateaus of both performance times and errors were lower for 3D. Independent of the vision mode the learning curves were smoother (exponential decay) and efficiency was learned faster than precision. The learning potentials varied widely depending on the corresponding initial values and learning plateaus. The final 2D performance time of the 3D-trained group was not significantly better than that of the 2D Group. The final 2D error numbers were similar for all groups.

Conclusions

Stereoscopic vision can speed up laparoscopic training. The 3D learning curves resulted in better precision and efficiency. The 3D-trained group did not show inferior performance in the final 2D cycle. Consequently, we encourage the training of surgical competences like suturing and knotting under 3D vision, even if it is not available in clinical routine.

Laparoscopic Robotic Surgery: Current Perspective and Future Directions

Just as laparoscopic surgery provided a giant leap in safety and recovery for patients over open surgery methods, robotic-assisted surgery (RAS) is doing the same to laparoscopic surgery. The first laparoscopic-RAS systems to be commercialized were the Intuitive Surgical, Inc. (Sunnyvale, CA, USA) da Vinci and the Computer Motion Zeus. These systems were similar in many aspects, which led to a patent dispute between the two companies. Before the dispute was settled in court, Intuitive Surgical bought Computer Motion, and thus owned critical patents for laparoscopic-RAS. Recently, the patents held by Intuitive Surgical have begun to expire, leading to many new laparoscopic-RAS systems being developed and entering the market. In this study, we review the newly commercialized and prototype laparoscopic-RAS systems. We compare the features of the imaging and display technology, surgeons console and patient cart of the reviewed RAS systems. We also briefly discuss the future directions of laparoscopic-RAS surgery. With new laparoscopic-RAS systems now commercially available we should see RAS being adopted more widely in surgical interventions and costs of procedures using RAS to decrease in the near future.

Cognitive load in 3d and 2d minimally invasive colorectal surgery

BACKGROUND

Three-dimensional (3d) laparoscopy has been introduced to enhance depth perception and facilitate surgical operations. The aim of this study was to compare cognitive load during 3d and 2d laparoscopic procedures.

METHODS

Two subjective questionnaires (the Simulator Sickness Questionnaire and the NASA task load index) were used to prospectively collect data regarding cognitive load in surgeons performing 2d and 3d laparoscopic colorectal resections. Moreover, the perioperative results of 3d and 2d laparoscopic operations were analyzed.

RESULTS

A total of 313 patients were included: 82 in the 2d group and 231 in the 3d group. The NASA TLX results did not reveal significantly major cognitive load differences in the 3d group compared with the 2d group; the SSQ results were better in the 3d group than in the 2d group in terms of general discomfort, whereas difficulty concentrating, difficulty focusing, and fatigue were more frequent in 3d operations than in 2d operations (p = 0.001-0.038). The results of age, sex, and ASA score were comparable between the two groups (p = 0.299-0.374). The median operative time showed no statistically significant difference between the 3d and 2d groups (median, IQR, 2d 150 min [120-180]-3d 160 min [130-190] p = 0.611). There was no statistically significant difference in the risk of severe complications between patients in the 3d group and in the 2d group (2d 7 [8.54%] vs 3d 21 [9.1%], p = 0.271). The median hospitalization time and the reoperation rate showed no difference between the 2d and 3d operations (p = 0.417-0.843).

CONCLUSION

The NASA TLX did not reveal a significant difference in cognitive load between the 2d and 3d groups, whereas data reported by the SSQ showed a mild risk of cognitive load in the 3d group. Furthermore, 3d laparoscopic surgery revealed the same postoperative results as 2d standard laparoscopy.

Is 3D faster and safer than 4K laparoscopic cholecystectomy? A randomised-controlled trial

BACKGROUND

Laparoscopic surgery has well-established benefits for patients; however, laparoscopic procedures have a long and difficult learning curve, in large part due to the lack of stereoscopic depth perception. Developments in high-definition and stereoscopic imaging have attempted to overcome this. Three-dimensional high-definition (3D HD) systems are thought to improve operating times compared to two-dimensional high-definition systems. However their performance against new, ultra-high-definition ('4K') systems is not known.

METHODS

Patients undergoing laparoscopic cholecystectomy were randomised to 3D HD or 4K laparoscopy. Operative videos were recorded, and the time from gallbladder exposure to separation from the liver (minus on table cholangiogram) was calculated. Blinded video assessment was performed to calculate intraoperative error scores.

RESULTS

One hundred and twenty patients were randomised, of which 109 were analysed (3D HD n = 54; 4K n = 55). No reduction in operative time was detected with 3D HD compared to 4K laparoscopy (median [IQR]; 23.41 min [17.00-37.98] vs 20.90 min [17.67-33.03]; p = 0.91); nor was there any decrease observed in error scores (60 [56-62] vs 58 [56-60]; p = 0.27), complications or reattendance. Stone spillage occurred more frequently with 3D HD, but there were no other differences in individual error rates. Gallbladder grade and operating surgeon had significant effects on time to complete the operation. Gallbladder grade also had a significant effect on the error score.

CONCLUSIONS

A 3D HD laparoscopic system did not reduce operative time or error scores during laparoscopic cholecystectomy compared with a new 4K imaging system.

A pilot study comparing ergonomics in laparoscopy and robotics: beyond anecdotes, and subjective claims

We aimed to use hand dexterity and grip strength test as objective measures to compare the difference in surgeon fatigue associated with robotic and laparoscopic colorectal surgery. We used the Purdue Pegboard Test to assess hand dexterity and the Camry Electronic Handgrip Dynamometer to assess hand grip strength. Eighteen patients were operated on, including 10 robotic and 8 laparoscopic cases. Statistical analysis revealed no difference in dexterity or muscle fatigue after operating with the robot. In contrast, there was a significant difference in the hand grip strength of both hands after laparoscopic surgery. Our results show that the resultant fatigue after laparoscopy affects both hands of the surgeon. In contrast, there was no difference in dexterity or muscle fatigue after operating with the robot. Given the demands of complex colorectal surgeries, robotics may be a means of optimizing surgeon performance by reducing fatigue.

3D laparoscopy does not reduce operative duration or errors in day-case laparoscopic cholecystectomy: a randomised controlled trial

Background

Contemporary 3D platforms have overcome past deficiencies. Available trainee and laboratory studies suggest stereoscopic imaging improves performance but there is little clinical data or studies assessing specialists. We aimed to determine whether stereoscopic (3D) laparoscopic systems reduce operative time and number of intraoperative errors during specialist-performed laparoscopic cholecystectomy (LC).

Methods

A parallel arm (1:1) randomised controlled trial comparing 2D and 3D passive-polarised laparoscopic systems in day-case LC using was performed. Eleven consultant surgeons that had each performed > 200 LC (including > 10 3D LC) participated. Cases were video recorded and a four-point difficulty grade applied. The primary outcome was overall operative time. Subtask time and the number of intraoperative consequential errors as identified by two blinded assessors using a hierarchical task analysis and the observational clinical human reliability analysis technique formed secondary endpoints.

Results

112 patients were randomised. There was no difference in operative time between 2D and 3D LC (23:14 min (± 10:52) vs. 20:17 (± 9:10), absolute difference − 14.6%, p = 0.148) although 3D surgery was significantly quicker in difficulty grade 3 and 4 cases (30:23 min (± 9:24), vs. 18:02 (± 7:56), p < 0.001). No differences in overall error count was seen (total 47, median 1, range 0–4 vs. 45, 1, 0–3, p = 0.62) although there were significantly fewer 3D gallbladder perforations (15 vs. 6, p = 0.034).

Conclusion

3D laparoscopy did not reduce overall operative time or error frequency in laparoscopic cholecystectomies performed by specialist surgeons. 3D reduced Calot’s dissection time and operative time in complex cases as well as the incidence of iatrogenic gallbladder perforation (NCT01930344).

Electronic supplementary material

The online version of this article (10.1007/s00464-019-06961-1) contains supplementary material, which is available to authorized users.

Endoscopic vitreoretinal surgery: principles, applications and new directions

Purpose

To analyze endoscopic vitreoretinal surgery principles, applications, challenges and potential technological advances.

Background

Microendoscopic imaging permits vitreoretinal surgery for tissues that are not visible using operating microscopy ophthalmoscopy. Evolving instrumentation may overcome some limitations of current endoscopic technology.

Analysis

Transfer of the fine detail in endoscopic vitreoretinal images to extraocular video cameras is constrained currently by the caliber limitations of intraocular probes in ophthalmic surgery. Gradient index and Hopkins rod lenses provide high resolution ophthalmoscopy but restrict surgical manipulation. Fiberoptic coherent image guides offer surgical maneuverability but reduce imaging resolution. Coaxial endoscopic illumination can highlight delicate vitreoretinal structures difficult to image in chandelier or endoilluminator diffuse, side-scattered lighting. Microendoscopy’s ultra-high magnification video monitor images can reveal microscopic tissue details blurred partly by ocular media aberrations in contemporary surgical microscope ophthalmoscopy, thereby providing a lower resolution, invasive alternative to confocal fundus imaging. Endoscopic surgery is particularly useful when ocular media opacities or small pupils restrict or prevent transpupillary ophthalmoscopy. It has a growing spectrum of surgical uses that include the management of proliferative vitreoretinopathy and epiretinal membranes as well as the implantation of posterior chamber intraocular lenses and electrode arrays for intraretinal stimulation in retinitis pigmentosa. Microendoscopy’s range of applications will continue to grow with technological developments that include video microchip sensors, stereoscopic visualization, chromovitrectomy, digital image enhancement and operating room heads-up displays.

Conclusion

Microendoscopy is a robust platform for vitreoretinal surgery. Continuing clinical and technological innovation will help integrate it into the modern ophthalmic operating room of interconnected surgical microscopy, microendoscopy, vitrectomy machine and heads-up display instrumentation.

2D versus 3D laparoscopic total mesorectal excision: a developmental multicentre randomised controlled trial

AIMS

The role of laparoscopy in rectal cancer has been questioned. 3D laparoscopic systems are suggested to aid optimal surgical performance but have not been evaluated in advanced procedures. We hypothesised that stereoscopic imaging could improve the performance of laparoscopic total mesorectal excision (TME).

METHODS

A multicentre developmental randomised controlled trial comparing 2D and 3D laparoscopic TME was performed (ISRCTN59485808). Trial surgeons were colorectal consultants that had completed their TME proficiency curve and underwent stereoscopic visual testing. Patients requiring elective laparoscopic TME with curative intent were centrally randomised (1:1) to 2D or 3D using Karl Storz IMAGE1 S D3-Link™ and 10-mm TIPCAM®1S 3D passive polarising laparoscopic systems. Outcomes were enacted adverse events as assessed by the observational clinical human reliability analysis technique, intraoperative data, 30-day patient outcomes, histopathological specimen assessment and surgeon cognitive load.

RESULTS

88 patients were included. There were no differences in patient or tumour demographics, surgeon stereopsis, case difficulty, cognitive load, operative time, blood loss or conversion between the trial arms. 1377 intraoperative adverse events were identified (median 18 per case, IQR 14-21, range 2-49) with no differences seen between the 2D and 3D arms (18 (95% CI 17-21) vs. 17 (95% CI 16-19), p = 0.437). 3D laparoscopy had non-significantly higher mesorectal fascial plane resections (94 vs. 77%, p = 0.059; OR 0.23 (95% CI 0.05-1.16)) but equal lymph node yield and circumferential margin distance and involvement. 30-day morbidity, anastomotic leak, re-operation, length of stay and readmission rates were equal between the 2D and 3D arms.

CONCLUSION

Feasibility of performing multicentre 3D laparoscopic multicentre trials of specialist performed complex procedures is shown. 3D imaging did not alter the number of intraoperative adverse events; however, a potential improvement in mesorectal specimen quality was observed and should form the focus of future 3D laparoscopic TME trials.

3D presentation in surgery: a review of technology and adverse effects

A systematic review was undertaken to assess the technology used to create stereovision for human perception. Adverse effects associated with artificial stereoscopic technology were reviewed with an emphasis on the impact of surgical performance in the operating room. MEDLINE/PubMed library databases were used to identify literature published up to Aug 2017. In the past 60 years, four major types of technologies have been used for reconstructing stereo images: anaglyph, polarization, active shutter, and autostereoscopy. As none of them can perfectly duplicate our natural stereoperception, user exposure to this artificial environment for a period of time can lead to a series of psychophysiological responses including nausea, dizziness, and others. The exact mechanism underlying these symptoms is not clear. Neurophysiologic evidences suggest that the visuo-vestibular pathway plays a vital role in coupling unnatural visual inputs to autonomic neural responses. When stereoscopic technology was used in surgical environments, controversial results were reported. Although recent advances in stereoscopy are promising, no definitive evidence has yet been presented to support that stereoscopes can enhance surgical performance in image-guided surgery. Stereoscopic technology has been rapidly introduced to healthcare. Adverse effects to human operators caused by immature technology seem inevitable. The impact on surgeons working with this visualization system needs to be explored and its safety and feasibility need to be addressed.

The use of 3D laparoscopic imaging systems in surgery: EAES consensus development conference 2018

BACKGROUND

The use of 3D laparoscopic systems is expanding. The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference with the aim of creating evidence-based statements and recommendations for the surgical community.

METHODS

Systematic reviews of the PubMed and Embase libraries were performed to identify evidence on potential benefits of 3D on clinical practice and patient outcomes. Statements and recommendations were prepared and unanimously agreed by an international surgical and engineering expert panel which were presented and voted at the EAES annual congress, London, May 2018.

RESULTS

9967 abstracts were screened with 138 articles included. 18 statements and two recommendations were generated and approved. 3D significantly shortened operative time (mean difference 11 min (8% [95% CI 20.29-1.72], I² 96%)). A significant reduction in complications was observed when 3D systems were used (RR 0.75, [95 CI% 0.60-0.94], I² 0%) particularly for cases involving laparoscopic suturing (RR 0.57 [95% CI 0.35-0.90], I² 0%). In 69 box trainer or simulator studies, 64% concluded trainees were significant faster and 62% performed fewer errors when using 3D.

CONCLUSION

We recommend the use of 3D vision in laparoscopy to reduce the operative time (grade of recommendation: low). Future robust clinical research is required to specifically investigate the potential benefit of 3D laparoscopy system on complication rates (grade of recommendation: high).

The use of 3D laparoscopic imaging systems in surgery: EAES consensus development conference 2018

BACKGROUND

The use of 3D laparoscopic systems is expanding. The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference with the aim of creating evidence-based statements and recommendations for the surgical community.

METHODS

Systematic reviews of the PubMed and Embase libraries were performed to identify evidence on potential benefits of 3D on clinical practice and patient outcomes. Statements and recommendations were prepared and unanimously agreed by an international surgical and engineering expert panel which were presented and voted at the EAES annual congress, London, May 2018.

RESULTS

9967 abstracts were screened with 138 articles included. 18 statements and two recommendations were generated and approved. 3D significantly shortened operative time (mean difference 11 min (8% [95% CI 20.29-1.72], I² 96%)). A significant reduction in complications was observed when 3D systems were used (RR 0.75, [95 CI% 0.60-0.94], I² 0%) particularly for cases involving laparoscopic suturing (RR 0.57 [95% CI 0.35-0.90], I² 0%). In 69 box trainer or simulator studies, 64% concluded trainees were significant faster and 62% performed fewer errors when using 3D.

CONCLUSION

We recommend the use of 3D vision in laparoscopy to reduce the operative time (grade of recommendation: low). Future robust clinical research is required to specifically investigate the potential benefit of 3D laparoscopy system on complication rates (grade of recommendation: high).

Development of three-dimensional laryngostroboscopy for office-based laryngeal diagnostics and phonosurgical therapy

OBJECTIVE

To develop a three-dimensional (3D) laryngostroboscopic examination unit, compare the optic playback quality in relation to established 2D procedures, and report the first case series using 3D rigid laryngostroboscopy for diagnosis and management of laryngotracheal diseases.

STUDY DESIGN

Laboratory study, prospective case series.

METHODS

The optical efficacy of newly developed rigid 3D endoscopes was examined in a laboratory setting. Diagnostic suitability was investigated in 100 subjects (50 male, 50 female) receiving 2D high-definition (HD) and 3D laryngostroboscopy. Two of the subjects subsequently underwent 3D-assisted office-based transoral phonosurgery under local anesthesia. Main outcome measures were comparative visualization of laryngotracheal pathologies, influence on preoperative planning, and evaluation of prognostic factors for the outcome of phonosurgical interventions.

RESULTS

Three-dimensional endostroboscopic procedures were effectively optimized to establish an examination protocol for all-day clinical use. Office-based 3D laryngostroboscopy was successfully applied in subjects with normal anatomy (n = 10) and various laryngotracheal findings (n = 90). In comparison to 2D HD videolaryngostroboscopy, the 3D view offered enhanced visualization of laryngotracheal anatomy, with qualitatively improved depth perception and spatial representation. In organic pathologies, this resulted in a more precise indication of phonosurgical procedures, increased accuracy in surgical planning, facilitated office-based endoscopic surgery, and better evaluation of prognostic factors for the outcome of phonosurgical interventions.

CONCLUSION

Three-dimensional laryngostroboscopy proved to increase the understanding of functional and surgical anatomy. Its application has enormous potential for improving the diagnostic value of laryngoscopy, surgical precision in laryngotracheal interventions, tissue preservation, and methods of teaching.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2823-2831, 2018.

A Suggestion on How to Compare 2D and 3D Laparoscopy: A Qualitative Analysis of the Literature and Randomized Pilot Study

BACKGROUND AND AIMS

The results of studies comparing two-dimensional (2D) and three-dimensional (3D) laparoscopy have shown variable results. We aimed to review the literature and develop an appropriate instrument to compare 2D and 3D laparoscopy. We further aimed to use the data extracted to perform a pilot study.

METHODS

Sixty-seven recent articles on 3D laparoscopy were reviewed and data extracted on factors influencing outcome variables. These variables were used to design a pilot study of 28 novices using a randomized crossover design. The results were analyzed using descriptive statistics and the Wilcoxon signed-rank tests.

RESULTS

Seven themes were identified to influence the outcome of 3D studies: applied technique (1), experience of subjects (2), study design (3), learning curve (4), subjective qualitative reports (5), laparoscopic tasks (6), and chosen outcome variables (7). The consecutively developed five laparoscopic simulation tasks contained placing a rubber band over hooks, ring and pearl transfer, threading a pipe cleaner through loops, and placing a suturise. The pilot study showed a primary benefit of 3D laparoscopy that was unrelated to repetition. Two tasks served well to assess first-time performance, and two tasks promise to serve well to assess a learning curve if performed repeatedly.

CONCLUSION

We were able to identify important issues influencing the outcome of studies analyzing 3D laparoscopy. These may help evaluate future studies. The developed tasks resulted in meaningful data in favor of 3D visualization, but further studies are necessary to confirm the pilot test results.

Laparoscopic radical prostatectomy in 2018: 20 years of worldwide experiences, experimentations, researches and refinements

INTRODUCTION

After the first feasibility report in 1997, a growing interest has risen in the urologic community for laparoscopic radical prostatectomy (LRP) and several authors have contributed to the evolution of the technique. We attempt a review of the available evidences and provide a broad framework of different technical refinements considering their impact on pentafecta.

EVIDENCE ACQUISITION

The PubMed/Medline database was searched. Duplicates and "Expert opinion" papers were removed. Studies were included according to the aim of the present paper to present a selected review on LRP and report our personal experience.

EVIDENCE SYNTHESIS

In 1999 Guillonneau et al. codified their transperitoneal-posterior-antegrade technique for LRP. Since then, several modifications of the transperitoneal approach were published and the extraperitoneal route was also proposed. Sparing the bladder neck and reconstructing the posterior muscolofascial plate were proven to improve continence rate. Nerve-sparing LRP were performed in order to maximize postoperative recovery of the sexual function. Novel techniques to ligate the Santorini plexus and sew the urethrovesical anastomosis provided improvement in operative time, intraoperative blood loss and reduced the incidence of postoperative urinary-leakages. In the recent years, the single-site approach as pushed the limits of LRP and three-dimensional (3D) systems for endoscopic surgery were developed.

CONCLUSIONS

Thanks to several technical improvements, LRP provides brilliant oncologic and functional outcomes and it is now considered the treatment of choice in many institutions worldwide. Although it is a technically demanding procedure, the recent introduction of 3D systems will reduce the steepness of its learning curve.