Abstract
Aim: The three-dimensional (3D) visualization system has been introduced for the technical improvement of laparoscopic surgery, but clinical evidence for its usefulness is lacking. This study aimed to evaluate the usefulness of a 3D system in laparoscopic surgery. Patients and Methods: Between 2015 and 2016, a randomized controlled trial was performed on 61 patients who underwent laparoscopic distal pancreatectomy. The primary outcome was the shortening of operative time. The hospital course, number of technical errors, and clinicians' subjective scores were compared as secondary outcome. Results: There were no significant differences in operative times, hospital course and technical errors. However, depth perception was significantly improved and physical demand was reduced in the 3D group. These advantages became clearer in the later period of the study, with longer operative times, and in spleen-preserving procedures. Conclusion: Subjective scoring through 3D systems was significantly superior, which might lead to better surgical performance in difficult cases.
Laparoscopic techniques can minimize surgical wounds, accelerate postoperative recovery, and reduce the duration of hospital stay compared to open techniques (1, 2). Previously, laparoscopic surgery depended on two-dimensional (2D) visualization technology, which presented remarkable challenges for those using this technique. These laparoscopic techniques have been further improved by the development of better surgical instruments (3-5). In particular, progression in camera technology has extended the scope of the application of laparoscopic systems, and more detailed surgery has become possible. Nevertheless, the improvement in high-quality cameras has not completely resolved the key limitations of 2D laparoscopy, such as lack of depth perception and visual strain (6, 7).
In the 1990s, three-dimensional (3D) visualization technology was proposed to facilitate laparoscopic performance (8, 9). In the early stage of 3D system introduction, there was a limitation of image enhancement, and its utilization was also insignificant. However, rapid innovation has provided more advanced 3D technologies that are important for the further development of minimally invasive surgery (10, 11).
A report indicated that the technical features and advantages of 3D systems are ineffective and limited (12), but other studies and reviews have suggested that 3D technology improves practical efficiency (13-15). In this study, we focused on laparoscopic distal pancreatectomy (LDP) as a form of laparoscopic abdominal surgery that requires at least 1 h of operative time. Our aim was to assess the benefits and harms of using the 3D versus the 2D system during LDP and to compare the parameters of imaging quality, adverse effects of surgery, and overall demands of laparoscopic technologies. Through this study, we expect to be able to comprehensively understand the 3D laparoscopic system and provide detailed information on its clinical application.
Patients and Methods
Study design. This study was performed in compliance with the Declaration of Helsinki. The study protocol was approved by the Institutional Review Board of ASAN Medical Center (IRB No. 2014-0924) and by the Clinical Research Information Service (registration number: NCT02757690). Written informed consent was obtained from all participants. Between 2015 and 2016, patients preoperatively diagnosed with a benign or borderline lesion in the distal pancreas by two radiologists using computed tomography (CT) or magnetic resonance imaging (MRI) were assessed for eligibility. Patients were divided into two groups (3D and 2D) using the block randomization method (16). Two expert surgeons and two first assistants participated. 2D surgery was performed using on Olympus (Seoul, Korea) 2D high definition (HD) laparoscopic system, and 3D surgery was performed using an ENDOEYE FLEX 3D system (LTF-190-10-3D; Olympus). Exclusion criteria were as follows: age ≤20 years or ≥80 years, body mass index (BMI) >30 kg/m2, history of severe or recurrent pancreatitis, tumor size in preoperative CT imaging >10 cm, history of major abdominal operation, and additional resection for an extra-pancreatic organ. The primary outcome was reduction of the operative time by at least 10 min through the 3D system. Operative time was defined as the time from port insertion to wound closure. The secondary outcome was to determine whether use of the 3D system was superior or not inferior to the 2D system for the following factors: Intra-hospital course, short-term outcomes, subjective scoring, and number of technical errors during the operation.
CONSORT diagram for the study.
Sample size. Our recent records of surgery were analyzed and showed that the average operation time for LDP was 200±59 min. The minimum number of patients to verify our hypothesis that the operative time could be reduced by at least 10 min using the 3D system was calculated. A sample size of 26 patients for each group was necessary to detect superiority using a one-sided design (81% power, two-sample t-test). The margin of superiority was −0.167. The true difference between the means was assumed to be −0.400. The significance level (α) of the test was 0.02500. All data were drawn from populations with standard deviations of 0.600 and 0.800 (17, 18).
Data collection. The analysis was divided into three parts: Clinical factors, subjective scoring of clinicians, and technical errors during surgery. The medical records were reviewed to collect their characteristics, hospital stay, time to start eating, recovery of general condition, pathological examination, blood results, and radiological examination parameters. The subjective scoring system was analyzed from the perspective of the operator and first assistant, which depended on three main categories: Image quality (scores of 1-9, bad to good), which included depth perception, sharpness, contrast, and ghosting; adverse effects (scores of 0-5, good to worse), which included visual strain, headache, facial discomfort, ear discomfort, and physical discomfort; and overall demand (scores of 0–5, easy to difficult), which included mental demand, physical demand, and performance success (12, 19). Finally, the operation video was analyzed to assess the operative time and the number of technical errors.
Statistical analysis. Statistical analyses were performed using SPSS version 21.0 (IBM, Armonk, NY, USA). Data are expressed as the average±standard deviation for continuous variables and as frequency for categorical variables. Student's t-tests and chi-square tests were used to analyze differences between the values of continuous and categorical variables, respectively. A p-value of less than 0.05 was accepted as statistically significant.
Results
Study design. A total of 63 consecutive patients were divided into two groups: 31 and 32 patients were assigned to the 2D and 3D system, respectively. Of the 31 patients in the 2D group, two with a history of abdominal surgery were excluded because of a more severe adhesion than expected (Figure 1). Twenty-one patients in the 2D group underwent a spleen-preserving procedure and eight had a spleen-sacrificing procedure. In the 3D group, 19 patients underwent a spleen-preserving procedure and 13 had a spleen-sacrificing procedure.
Demographics and short-term outcomes of patients. The patient and tumour characteristics were compared (Table I). There were no significant differences in age, gender, BMI, past history, laboratory results, operator, and pathological diagnosis. In addition, the various clinical features and short-term outcomes were also analyzed (Table II). There was no transfusion during operation, and no significant difference in the ratio of spleen-preserving, inflammation, hemorrhage, recovery pattern, re-operation, and re-admission between the two groups.
Host and tumor characteristics of the study population.
Surgical technique and subjective scoring according to visualization system. Differences in the technical aspects were analyzed through a review of the surgical videos, and the subjective scoring of operators (Table III). The operative time, which was the subject of the primary outcome, was similar for both groups. Among the items of technical error, the frequency of missed grasps appeared to decrease slightly in the 3D group, but this was not significant. However, image quality was superior and the mental and physical demands were significantly reduced in the 3D system. Next, the analysis was conducted between the first 10 cases and the later cases. The adverse effects (headache, physical discomfort) and overall demand (mental and physical demand) of the 3D system decreased remarkably in the later period.
Further analysis was conducted to determine whether these factors were affected by the operative time and surgical procedure. Firstly, the operative time was divided into three categories based on cutoffs of 120 min and 180 min. There were no differences in the average operative time between the 2D and 3D groups in the three categories. As the operative time increased, the number of technical errors also increased. The degree of increase was more pronounced for missed grasps, but there were no significant differences between the two groups (Figure 2A). In Figure 2B-D, the comparison of subjective scores by operative time showed that the advantages of the 3D system became clearer with longer operative time.
Secondly, we analyzed the influence of the surgical procedure. Patients were divided into two categories by spleen-preserving procedure (Table IV). The difference between the two groups was clear in the spleen-preserving procedure rather than the spleen-sacrificed procedure. In particular, depth perception, sharpness, and contrast increased relatively and mental and physical demand was relatively reduced in the 3D system.
Surgical technique and subjective scoring between operator and first assistant. A comparative analysis of the subjective scoring between the operators and first assistants was performed. Except for ear discomfort, there was no difference between the two groups (Table V). The six factors (depth perception, sharpness, contrast, physical discomfort, mental demand, and physical demand) that differed from the subjective scoring analysis between the operators (Table III) were compared with the results of the first assistant. Of these, three factors (depth perception, sharpness, contrast) related to imaging still showed superiority in 3D systems (Table VI).
Discussion
In 1992, the 3D visualization system was introduced to improve image quality and reduce the learning curve required for surgeons to reach high performance levels (20-22). Recently, improved optics has allowed for more accuracy in spatial distance and hand–eye coordination, which lead to increased accuracy in performance and hand-grasping (11, 23, 24). Nevertheless, the application of 3D systems is still limited, and additional research on their scope and utility is required. Most of the previous clinical studies were performed on relatively simple operations of less than 1 hour (12, 13, 15). 3D systems can be useful in relatively more complex and sophisticated operations (25-27). Considering the difficulty of the surgical technique and the operative time, we decided that LDP is a suitable model for confirming the usefulness of the 3D system. By conducting a randomized control study through a well-designed study, we found the following interesting results.
Clinical outcomes after laparoscopic distal pancreatectomy.
Firstly, an objective result of improvement in technique through the 3D system was not confirmed. As shown in Table II, the operative time, which was the parameter and primary outcome of the surgical technique, was not shortened, and there were no significant differences in frequency of technical errors. These findings are consistent with those in published articles (12, 28). Considering that the participating surgeons were experts who had already performed more than 100 cases of LDP using the 2D system, it may be difficult to identify a dramatic improvement of their surgical technique.
Secondly, 3D systems exhibit superior image quality, particularly in depth perception, sharpness, and contrast. Consistent with these results, the mental and physical demands on surgeons decreased in the 3D group, which is supported by a previous study that investigated image quality and overall demand of the 3D system (12). These findings may be explained by the advanced visualization optics that allows for more accuracy in spatial distance perception and hand–eye coordination. The better image quality might relate to optical shuttering glasses, which reduce photo transmission to the retina and lead to a decline in the sensory impact on color vision (29). Interestingly, these advantages became clearer in the later period of the study, with longer operative times, and in more complex surgical procedures. This reflects the feasibility and accessibility of this system, which may reduce the burden on the operator, particularly in difficult cases. Although these advantages are not directly related to shortening of the operative time, operations will be more effective as the burden on the operator decreases.
Frequency of technical errors (A) and subjective scoring of laparoscopic distal pancreatectomy according to operative time (B-D) between 2D and 3D groups. Significantly different at *p<0.01, **p<0.005 and ***p<0.001.
Technical errors and subjective scoring of laparoscopic distal pancreatectomy according to study period and method.
Technical errors and subjective scoring of laparoscopic distal pancreatectomy according to spleen preservation and method.
Subjective scoring (mean±SD) of laparoscopic distal pancreatectomy of the operator and first assistant according to method.
Technical errors and subjective scoring (mean±SD) of the first assistant in laparoscopic distal pancreatectomy.
Thirdly, the first assistant unlike the operator, experienced no reduction of physical demand through the 3D system. Among the subjective scoring results of the operators, only the imaging quality-related factors showed superiority for the first assistant. As far as we are aware, this study is the first to compare operator and first assistant scoring, these results may be a reflection of a difference in concentration and burden between the two.
This study was the first study to validate the clinical usefulness of the 3D system for LDP with an operative time of at least 1 h. The 3D system did not shorten the operative time nor reduce technical errors. However, superiority of the 3D system was confirmed by subjective scoring such as imaging quality and physical demand, particularly in longer and more complicated procedures. Through extensive research on the 3D system, we hope to find a clearer answer to the clinical usability and scope of the 3D system.
Footnotes
↵* These Authors contributed equally to this work.
Authors' Contributions
Substantial contributions to the conception or design of the work: Eunsung Jun, Abdulwahab A. Alshahrani, Sang Hyun Shin, Dae Wook Hwang, Ki Byung Song, Jae Hoon Lee, Young-Joo Lee, Song Cheol Kim; Acquisition of data: Dae Wook Hwang, Ki Byung Song, Jae Hoon Lee, Young-Joo Lee; Analysis and interpretation of data: Eunsung Jun, Abdulwahab A. Alshahrani, Sang Hyun Shin, Young-Joo Lee; Statistical Analysis: Sang Hyun Shin, Dae Wook Hwang, Ki Byung Song, Jae Hoon Lee; Drafting of manuscript: Eunsung Jun, Abdulwahab A. Alshahrani, Song Cheol Kim; Critical revision: Eunsung Jun, Abdulwahab A. Alshahrani, Song Cheol Kim; Thereafter, in the final revision of this manuscript, all Authors discussed the interpretation of the data and intellectual contents.
Conflicts of Interest
No potential conflict of interest relevant to this article was reported.
Funding
This study was supported by a Grant from the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (No. HI14C2640) and by a grant (2017-7033) from the Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea.
- Received January 3, 2019.
- Revision received January 21, 2019.
- Accepted January 22, 2019.
- Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved
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