Performance of three-dimensional and ultra-high-definition (4K) technology in laparoscopic surgery: A systematic review and meta-analysis.

Background: The technology in the field of laparoscopy is rapidly evolving and is primarily focussed on increasing the quality of image and depth perception in the form of 4K and three-dimensional (3D) technology. There has been no conclusion yet regarding the better technology.
Methods: A systematic search was performed independently by two authors across MEDLINE, Google Scholar and Embase using the PRISMA guidelines. All randomised control trials comparing 3D and 4K technologies were included. Meta-analysis was conducted using random-effects statistics for time taken for different tasks across the studies.
Results: The search strategy revealed a total of 1835 articles, out of which nine studies were included. Three studies showed no superiority of 3D over 4K, while the remaining six did. Meta-analysis for the time taken for peg transfer favoured 3D over 4K (overall effect: Z = 2.12; P = 0.03). Forest plots for time taken for suturing (Z = 1.3; P = 0.19) and knot tying (Z = 1.7; P = 0.09) also favoured 3D over 4K; the results however were statistically insignificant. Path length was reported by two studies and was found to be lesser in the 3D group. Two studies measured the workload by NASA/Surg-TLX score, which was lower in the 3D group. Visual side effects were found to be higher in the 3D group.
Conclusion: 3D technology is likely to result in a shorter operative time and better efficiency of movement as compared to the 4K technology by the virtue of its better depth perception.

INTRODUCTION

The technology in the field of laparoscopic surgery is rapidly evolving. Since the foundation laid by Georg Kelling and H. C Jacobaeus,[1] there have been various advances in the field of laparoscopic surgery, most of them are focussing on to increase the quality of image and the depth perception. Although by practice and experience, surgeons acquire the ability to obtain monocular depth perception, the inability to perceive adequate depth is still a major limitation of laparoscopic surgery. The regular high-definition (HD) endovision system has a resolution ranging of 1080 pixels. It provides adequate image quality and is presently the preferred endovision technology.

Limitation caused by lack of depth perception was recognised by surgeons since early days of laparoscopic surgery. Attempts were made to overcome this by developing a three-dimensional (3D) endovision system. The first clinical use of stereo-endoscope was reported by Becker et al.[2] The latest generation high-definition 3D technology has effectively minimised the user-related post-procedural adverse effects such as headache, vomiting and dizziness which were frequent with previous generation of 3D technology. With advancement of technology, the 3D HD endovision system has gained a gradual acceptance among laparoscopic surgeons worldwide.[3456] The European Association of Endoscopic Surgery reached a consensus that the use of 3D technology was associated with not only a shortened operative time but also a significant reduction in complication rate, especially in surgeries that involved laparoscopic suturing.[7]

Recently, an ultra-high-definition (4K) technology has evolved to improve the depth perception in laparoscopic surgery. The 4K technology has a resolution of 3840 × 2160 pixels. The high-quality and large image of 4K system provides monocular depth perception by virtue of indirect visual cues, shadows of the structures, motion parallax, colour and contrast of the operative field. The 4K technology has been found to be useful in reducing intra-operative blood loss and operative time.[8] The 4K system is essentially an extension of existing two-dimensional working environment. Other advantages of 4K system such as availability of 5 mm optic, easy to rotate the angled optic and no requirement to wear polarised goggles during surgery have made it a possible alternative to 3D HD technology.

With availability of various technologies, it has become difficult for the users to choose the best endovision system. The preferred technology should facilitate a surgeon to perform the surgery faster without compromising procedural safety and with no adverse effect to the surgeon. There are several studies comparing the effectiveness of 3D HD and 4K technologies. Most of these studies have evaluated the time taken for task completion, error rates and surgeons’ workload. However, the results in different studies are varied with no clear conclusion or recommendation for one technology over the other. We conducted a systematic review of randomised trials to draw conclusion in this regard and to find out the lacunae for possible future research.

METHODS

Search strategy

The literature search was performed by two authors (VS and HB) across PubMed, Embase and Google Scholar. The search in PubMed, Embase and Google Scholar revealed 1109, 94 and 819 articles, respectively. Various combinations of ‘3d, 3D, 4k, 4K and laparoscopy’ were used for the search. The initial literature search was carried out on 26 October 2020 and updated on 26 March 2021. All the articles in English were screened by titles, abstracts and full text if required. Articles were also included from the references of the articles obtained through the search. The sample size and year of publication were not taken into consideration for inclusion in the systematic review due to the paucity of data. Articles providing unpublished data such as editorials and thesis were excluded. Studies comparing the 3D with the 4K technology were included. Studies other than the randomised control trials were excluded. Finally, seven studies were identified for inclusion. The intervention group use 3D technology, whereas the use of 4K was kept as the control group. The details of selection of articles in accordance with the PRISMA guidelines are shown in Figure 1.

Figure 1

PRISMA chart

Data extraction

The data were extracted from each study by two authors independently (VS and EG). Agreement was reached by mutual consensus after consultation with a senior author (HB). The information extracted from each study included the year of publication, first author, study design, sample size, time taken and error rates in the 3D and 4K groups in various tasks, path length, side effects and workload assessment wherever available. The primary objective was to compare the time taken and errors in the 3D and 4K technology. Other parameters such as path length, workload and visual side effects were also compared. There was a significant heterogeneity in the tasks used and the methodology to compare 3D and 4K technologies within the studies.

Assessment of study quality

The risk-of-bias assessment was performed using the Cochrane risk assessment tool Review Manager (RevMan) [Computer program]. Version 5.4, The Cochrane Collaboration, 2020. The risk-of-bias summary shows judgements of authors regarding each risk-of-bias item for every study which is included. The risk-of-bias graph shows judgements of authors regarding each risk-of-bias item which is presented as percentages across all the included studies. The details are shown in Figure 2.

Figure 2

Figure showing the risk of bias assessment for the studies included

Statistical analysis

The meta-analysis of extracted data was conducted using Cochrane Review Manager 5.2.6. (http://ims.cochrane. org/revman). A fixed-effects model or random-effects model was used, depending on the absence or presence of heterogeneity (explained in the next section). The time taken to perform different tasks including peg transfer, suturing and knot tying using 3D or 4K technologies in different studies was used to estimate overall mean difference.

Exploring heterogeneity

Heterogeneity was calculated using the Higgins Chi-square test, and inconsistency was quantified by I2. A Chi-square test with a P < 0.10 was considered to indicate the presence of heterogeneity, and an I2 >50% was considered to suggest marked inconsistency in effect between studies. A funnel plot was not conceived in view of the number of studies being <10.

RESULTS

A total of nine randomised control studies with 600 participants were included in the systematic review.[91011121314151617] All the studies reported the time taken and error rates for various tasks performed. Two studies included the workload assessment using the NASA TLX[14] /Surg TLX[15] questionnaire. Two studies reported visual side effects in both the procedures.[913] There were two in vivo studies in patients undergoing laparoscopic cholecystectomy,[1017] Heller's myotomy and laparoscopic hernia repair,[17] which reported time taken, errors and postoperative complications in both the groups. The summarised salient features of each study are presented in Table 1.

Table 1

The salient features of each study

Study characteristics	Sample size	Participants (expert/novice)	Tasks	Results in 3D compared to 4K	Comments
Abdelrahman et al. 2018	24	Novice (24) 8 in 2D 8 in 3D 8 in 4K	Laparoscopic peg transfer Intra-corporeal suturing	Mean performance time (min): 3D group: 316.7; 4K group: 310.4; (P<0.0001) Mean number of repetitions: 3D group: 125.9; 4K group: 127.4; (P<0.0001) Mean number of errors: 3D: 26.1; 4K group: 1.2; (P<0.0001)	The 4K technology improves the accuracy of laparoscopic surgery in complex tasks
Bhattacharjee et al. 2020	21	Novice (21) 7 in 2D 7 in 3D 7 in 4K	Peg transfer Precision cutting Navigating in space Intra-corporeal suturing	Shorter execution time in 3D compared to 4K (except precision cutting) Similar error scores in both groups Less workload in the 3D group	3D HD results in faster execution of task without compromising on the safety
Dunstan et al. 2020	109	Experts 54 in 3D 55 in 4K	Task: Laparoscopic cholecystectomy	Operative time:  3D (23.41 min [17.00-37.98])  4K (20.90 min [17.67-33.03]); P=0.91 Error scores:  3D: 60 (56–62); 4K: 58 (56-60); P=0.27	3D and 4K similar in terms of operative time and error rates in vivo
Harada et al. 2018	11	Expert	3 laparoscopic suturing tasks Task 1: Simple suturing Task 2: Knotting thread in a small box Task 3: Suturing in a narrow space	3D/HD was significantly better than 4K in simple suturing. (P=0.017, 0.033 and 0.492 for operative time, path length, and technical errors, respectively) In tasks 2 and 3 (operation in narrow spaces), performances using 2D/4K were not inferior to 3D/HD performances	3D and 4K have similar performance in narrow spaces
Kanaji et al. 2019	66	Novice 22 in 3D 22 in 4K 22 in 2D	Task 1, touching markers on a non-flat surface Task 2, bimanual peg transfer Task 3, passing a straight rod through a loop	3D monitor were significantly better than 4K with respect to operative time, path length and technical errors	The benefit of 3D was most pronounced as far as the time taken to complete a task was concerned
Rana et al. 2019	40	Novice	4 tasks:  Passing needle through a ring  Knot tying  Cutting circle  Touching circles with a needle	Significant difference in errors, with 3D showing reduction in errors for passing needle through a ring, knot tying, cutting circle and touching circles with a needle	The study showed no significant difference in the time to perform tasks. The precision of the tasks was significantly improved with the 3D systems
Wahba et al. 2020	128	Experts and novice 49 medical students 39 non-board-certified surgeons 40 board-certified surgeons	7 tasks  Rope pass  Paper cut  Pegboard transfer  Needle threading  Needle recapping  Circle cutting  Knot tying Medical students did not perform the tasks ‘circle cutting’ and ‘knot tying’	Overall Parkour time (s): 3D (712.5 s); 4K (999.5 s); P<0.001 for all experience levels Overall number of mistakes: 3D (10.0); 4K (13.3); P<0.001 The NASA-TLX score was lower with 3D	3D laparoscopic display technique optimises surgical performance compared to the 4K technique even for expert surgeons
Thomaschewski et al. 2021	62	Novice	Learning skills on LTB video box trainer (4 tasks including suturing)	3D system required fewer repetitions to achieve goals for simple tasks. #D and 4K were similar for complex tasks	Learning curve might be lesser when using 3D technology
Parshad et al. 2021	139 (patients)	Expert	3D group:  Cholecystectomy: 30  TAPP: 23  Heller’s cardiomyotomy: 15 4K group: Cholecystectomy: 30 TAPP: 24 Heller’s cardiomyotomy: 15	Mean operative time in 3D versus 4K  Cholecystectomy (52.7 vs. 56.2, P=0.50)  TAPP (63.8 vs. 69.6, P=0.25)  Heller’s cardiomyotomy (124.7 vs. 143.3, P=0.14), but with faster hiatal dissection in 3D group by 8 min (P=0.02) Heller’s cardiomyotomy (124.7 vs. 143.3, P=0.14), but with faster hiatal dissection in 3D group by 8 min (P=0.02) Total workload was similar in 3D and 4K groups in all the procedures but mental and physical demand was lower in 3D group in Heller’s cardiomyotomy	3D might be beneficial in advanced laparoscopic procedures

LTB: Lübeck Toolbox, 3D: Three-dimensional, 4K: Ultra-high-definition, TAPP: Trans-abdominal pre-peritoneal, HD: High definition, NASA-TLX: NASA task load index

Studies showing no superiority of 3D over 4K technology

Harada et al.[11] compared three parameters - operative time, path length and technical errors - during the task performance by 11 expert laparoscopic surgeons in 3D and 4K systems. A total of three tasks including simple suturing, knotting a thread around rubber bands in a small box and suturing in a narrow space were performed. Initially, all the subjects performed the task five times on a 2D monitor. After this initial training, six participants performed the tasks on 3D followed by 4k. Similarly, five participants performed the tasks first on a 4K monitor followed by 3D. The operating time was lower in the 3D group in case of simple suturing, whereas it was similar in rest of the two tasks. The performance of 3D was similar to 4k in task 2 and task 3, both of which involved narrow spaces.

Dunstan et al.[10] analysed 54 and 55 patients undergoing laparoscopic cholecystectomy in 3D and 4K, respectively. They compared the 3D and 4K technologies in terms of operative time and error (major and minor) rate. The operative time was 23.41 min in the 3D and 20.90 min in the 4k group. The operative time in difficult cases (dense adhesions, difficult anatomy and stone at the neck of the gallbladder) was similar in the 3D and 4K groups (48 min vs. 38.69 min; P > 0.05). The minor error rate was similar in both the groups. There were seven gallbladder injuries with stone spillage in the 3D group and only one in the 4K group. The complication rates were also similar in both the groups.

Abdelrahman et al.[9] compared 3D, 4K and 2D technologies and included eight novice participants in each group. All the participants performed two tasks of peg transfer and suturing in a box trainer. Peg transfer was completed in a lesser time in the 3D group and suturing took lesser time in the 4K group. The results were although statistically not significant. There were significantly less errors in the 4K group in the task of suturing. The errors were also lesser in the 4K group for peg transfer, but the results were not statistically significant. Based on a Likert scale, the participants felt that depth perception and hand eye coordination were better in the 3D group but at the cost of higher eye strain, perceived difficulty to focus and blurred vision.

Studies showing superiority of 3D over 4K

Wahba et al.[14] performed a randomised trial on 128 subjects. These subjects included ‘medical students’ with no exposure to laparoscopy, ‘non-board-certified surgeons’ and ‘board-certified surgeons. They completed various tasks using 3D or 4K technology. The workload assessment was performed using the NASA-TLX score. The time taken to complete the tasks in 3D and 4K groups by the students was 555.4 s and 858.7 s, for non-board-certified surgeons was 935.9 s and 1274.1 s and for board-certified surgeons was 646.3 s and 865.7 s, respectively. The results were statistically significant. The error rate was higher while using the 4K technology for all the participants. The errors were less in the 4K group only in the tasks of ‘paper cut’ and ‘circle cut’ when performed by students and board-certified surgeons.

Kanaji et al.[12] in their study compared 3D, 4K and 2D technologies. There were 22 participants with no surgical training in each group. They performed three tasks including ‘touching markers on a nonflat surface’, ‘bimanual peg transfer’ and ‘passing a straight rod through a loop’. The operative time, errors and the path length were then compared. Ten expert surgeons were also included who served as controls and performed the tasks in all the three technologies. The operative time was found to be shorter in the 3D group for all the tasks. The path length in task 3 was shorter in the 3D group and the errors in the task 2 and 3 were also less in the 3D group. The experts also had a shorter time for the tasks 1 and 3 when using 3D. They also had less errors in task 3 while using 3D. However, nausea and dizziness were also more common in the 3D group as compared to other groups.

Rana et al.[13] compared 3D versus 4K technology using 40 (20 in each group) medical students with no exposure of laparoscopy. They used total time and error rate for comparison. The tasks included touching circles with a needle, transfer of ring, passing needle through two circles, cutting circle and knot tying. They found that the time taken was significantly more in the 4k group for cutting a circle and knot tying. The error rate was higher in 4k for the tasks of cutting circle, touching circle and passing needle through circle. The time taken and error rate were similar in both the groups for rest of the tasks.

Bhattacharjee et al.[15] compared execution time and error scores for the tasks: peg transfer, precision cutting, navigation in the space and intra-corporeal suturing. The subjective workload was also compared using Surg-TLX score. A total of 21 laparoscopy-naïve participants were included in the study. The execution time using the 3D technology was significantly shorter in all the tasks except for precision cutting. The error score was also lesser for 3D in all the tasks except for peg transfer although statistically insignificant. The subjective workload was found to be least with the 3D technology. Moreover, the mental demand and situational stress were also lesser with the 3D vision system.

Thomaschewski et al.[16] evaluated the number of repetitions required to satisfactorily complete a task using 3D and 4K technologies. The time taken, error rates were not reported. They found that the number of repetitions required for simple laparoscopic tasks was significantly lesser in the 3D group. In complex tasks such as suturing, the number of repetitions was still lesser in the 3D group; however, the difference did not reach statistical significance.

Parshad et al.[17] compared 3D and 4K technologies in vivo. They evaluated the time taken to perform the surgeries and performed a workload assessment in both the groups. It was seen that the time taken was similar in both the groups as far as laparoscopic cholecystectomy and trans-abdominal pre-peritoneal repair were concerned. The time taken was shorter in the 3D group for hiatal dissection during Heller's myotomy. The workload was also found to be lesser in the 3D group during Heller's myotomy. The workload was similar in other two surgeries.

Quantitative synthesis

Three studies were included for quantitative synthesis of the time taken for the task of peg transfer[121415] as shown in Figure 3. The study by Wahba et al. reported time taken for novice group (medical students) and expert group (board-certified surgeons) separately. The forest plot in Figure 3a includes only the novice group from the study, and the plot in Figure 3b includes both novice and expert groups from the study. 3D was better as compared to 4K; however, there was significant heterogeneity (I2 >95%) [Figure 3]. Inclusion of only the novice group revealed an overall Z effect of 2.12 [Figure 3a]. The overall Z effect was better when the expert group (Z = 3.04) was also included for the analysis [Figure 3b]. The results were statistically significant (P < 0.05).

Figure 3

Forest plot comparing time taken for Peg transfer in three-dimensional HD and 4k; (a) Only novice participants included, (b) Both novice and expert participants included

Three studies were included for the task of knot tying.[111314] The result appeared to favour the 3D technology (overall effect Z = 1.7). It was, however, statistically insignificant with a significant heterogeneity (P = 0.09; I2 = 98%) [Figure 4]. Two studies were included for the task of suturing.[1115] The study by Harada et al. reported times for simple suturing and suturing in narrow spaces separately. Both these subgroups were included for the quantitative synthesis. The results again favoured the 3D technology but were statistically insignificant with no heterogeneity (Z = 1.31, P = 0.19; I2 = 0%) [Figure 5].

Figure 4

Forest plot comparing time taken for Knot tying in three-dimensional HD and 4k

Figure 5

Forest plot comparing time taken for suturing in three-dimensional HD and 4k

DISCUSSION

The use of laparoscopy has resulted in shorter recovery times and decreased postoperative morbidity. It had certain drawbacks including two-dimensional vision and poor quality of image as compared to that seen in open surgery.[18] Various technologies have come up including 3D and 4K to overcome these obstacles.[45819] With availability of technology, there is a gradual penetration of 3D and 4K system into the clinical arena. The nation-wide study from Italy suggested that 25% of laparoscopic right colectomies are performed using 3D system, while 6% are with 4K system. Since 4K is a recent technology, the use of these technologies is likely to increase further in due course of time.

Most of the studies in our systematic review showed faster execution of task in 3D system compared to in 4K system. The better binocular depth perception with 3D system may be the reason for it.[1112] While looking at the errors, most of the studies have shown comparable errors with both the technologies.[1015] Comparable error scores with faster task performance, placed 3D technology in an advantageous position, as this finding may translate that 3D would deliver faster surgery without compromising the safety of a procedure. Due to the heterogeneity of task assayed in various studies, we could not perform a meta-analysis for all the tasks. The results of the quantitative synthesis also showed that the 3D technology resulted in lesser operative time for peg transfer, suturing and knot tying. The results were statistically significant for the task of peg transfer. This leads to an inference that 3D technology is likely to result in shorter operative times, especially for simple laparoscopic tasks. However, on quantitative synthesis, it was seen that 3D technology had lesser error rate as far as peg transfer was concerned which was again statistically insignificant. There was no preference for 3D for other tasks in the quantitative synthesis.

The task performed in most of the studies is obtained from the FLS or designed indigenously. The monocular depth perception in 4K relies on indirect depth cues provided by the superior image quality and colour contrast. The remarkable image quality of 4D confers a contrast between the object of interest and the surroundings, thus (indirectly) enhances the depth perception immensely.[11] The impact from surroundings may not be adequately simulated on some of these experimental tasks, as seen in a few studies.[121314] Harada et al. showed that in narrow space surgical manoeuvres, 4K system performs better or similar to the 3D system. It was suggested that shading of the target objects and the surroundings may be enhanced by the high-resolution imaging in 4K HD in narrow spaces, hence providing better indirect depth cues.[11] To bring out the best performance of 4K system, simulated task also needs modification, which will be more clinically relevant. The clinical study by Dunstan et al., comparing 3D and 4K, showed equivalent result.[10] The procedure they compared was laparoscopic cholecystectomy. More technically demanding procedures may have provided us more useful information on superiority of one technology over others. The number of repetitions was found to be similar in both the 3D and 4K technologies when the tasks were performed in closed spaces.[16]

The time taken for completion of tasks was invariably reported in all the studies. Some studies reported a shorter execution time in the 3D group,[121415] while some reported similar times in both the groups.[9101113] Two studies were performed in vivo, and the time taken for cholecystectomy was similar in both the groups.[1017] The time taken for Heller's myotomy which requires advanced laparoscopic skills was lesser in the 3d group.[17]

Harada et al. had an interesting observation of similar suturing times in both the groups while suturing in narrow spaces, whereas they were lower in the 3D group when simple suturing was performed.[11] The studies indicate that the visual cues obtained from the surroundings play an important role in the performance of the task. The narrow space simulated an in vivo environment, and the visual cues are easy to be achieved in such surroundings. 4K technology provides a very high-quality image to achieve such visual cues and result in similar performance. The 3D technology might have an edge where performance of complex tasks is required. Nonetheless, considering the results of the studies included in the systematic review, the 3D technology appears to shorten the execution time of various tasks. Moreover, a study also showed that the execution times were shorter in the 3D for medical students as well as trained surgeons. The results of the quantitative synthesis also showed that the 3D technology resulted in lesser operative time for peg transfer, suturing and knot tying. The results were statistically significant for the task of peg transfer. This leads to an inference that 3D technology is likely to result in shorter operative times, especially for simple laparoscopic tasks.

Majority of the studies also reported the error rates/mistakes for the various tasks which indirectly impact the operative time and efficiency of surgery with variable results. Two studies reported lesser error rates with the 4K technology.[910] Rest of the studies showed either similar results in both the groups[15] or favoured the 3D technology.[11121314] The in vivo study by Dunstan et al. showed similar error rates in 3D and 4k groups, except for a higher rate of stone spillage from injury to gallbladder in the 3D group.[10] Overall, the results favour the 3D group slightly with regard to the error rate; however, this might not be significant in the clinical setting.

Another important parameter reported in two of the included studies is the path length of the instrument. It translates into unnecessary movements in vivo and thus efficiency of performing the task. In one study, the path length was greater in the 4K group as compared to the 3D group in the task of simple suturing or suturing in narrow space.[11] Another study reported greater path length in the 4K group in the task of passing a rod through the loop. The path lengths were similar in both the groups in the tasks of navigation and peg transfer.[12] A common inference that can be deduced from the findings, 3D technology in view of its greater depth perception, results in a shorter path length in the tasks where movement in depth is required, i.e., a movement in all the three dimensions is required. The path length for peg transfer which essentially involves movement in a two-dimensional plane was found to be similar. As earlier discussed, intra-corporeal suturing is an advanced laparoscopic task and the use of 3D technology reduced the path length for suturing but had no effect while knotting around rubber bands. The in vivo study also favoured 3D over 4K for advanced laparoscopic surgery.[17] Another important observation was that the path length was lesser in the 3D group even while suturing in narrow spaces questioning the hypothesis of cues from narrow spaces in 4K technology. However, more in vivo studies are required to have a stronger conclusion in this aspect.

Visual side effects and fatigue have been reported with the 3D technology in various studies.[2021] In this review, two studies compared the visual side effects in the 3D and 4K groups.[913] Visual side effects including blurred vision, eye strain and difficulty focussing were significantly higher in the 3D group as compared to the 4K group.[9] Another study also found that the participants preferred 4k over 3D as far as headache and visual strain were concerned.[13] Thus, the 3D technology is likely to result in higher visual side effects. Decreased peripheral vision, inability to manoeuvre the camera as in 2D/4K and adjustment problems with 3D image can result in higher visual side effects in 3D technology. Workload was found to be lesser in the 3D group when done by NASA-TLX[14] or Surg-TLX,[1517] especially for complex tasks. Workload reflects the difficulty in depth perception. 4K due to its high-quality image had a lesser workload than in 2D technology, but still 3D technology had lesser workload as compared to 4K. In two of these studies,[1415] workload assessment was done while performing the tasks ex vivo. In the in vivo study, the workload was again found to be lesser in the 3D group with similar surgeon satisfaction scores in both the groups. The visual side effects were however not reported in the study. The visual side effects and workload need to be considered together while choosing one technology over another. The higher incidence of visual side effects might overcome the advantage from decreased workload in the 3D group. 3D technology can be chosen over the 4K while performing advanced laparoscopic surgeries.

This was the first systematic review to compare the 3D and 4K technologies with an attempt of quantitative synthesis. The 3D technology is likely to be better than the 4K as far as the parameters of time taken, error rate, path length and workload are concerned. The reported data in different studies were quite heterogenous precluding the performance of meta-analysis for all the parameters. Seven of the nine randomised controlled trials included were performed in a simulated setting and only two were performed in a clinical setting. Moreover, the simulated task used to assess these technologies may not be the perfect for the purpose. Thus, further studies in the clinical setting are required to make a strong conclusion in favour of 3D technology. Although reported by two studies only, visual side effects were higher in the 3D technology which should be taken into consideration, given the generally longer duration of surgeries than the tasks performed in simulated settings.

CONCLUSION

3D technology is likely to result in a shorter operative time and better efficiency of movement as compared to the 4K technology by the virtue of its better depth perception. The incidence of visual side effects is higher in 3D as compared to 4K.

Ethical clearance

A formal ethical clearance was not required for this study.

Informed consent

Informed consent was not applicable for this type of study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.