Perioperative,Pathologic,and Early Continence Outcomes Comparing Three-Dimensional and Two-Dimensional Display Systems for Laparoscopic Radical Prostatectomy

Abstract

Purpose:

To examine perioperative, pathologic, and early continence outcomes of laparoscopic radical prostatectomy (RP) aided by a new-generation three-dimensional (3D) display system and compare them with those from the same operation aided by a conventional, two-dimensional (2D) display system.

Patients and Methods:

A total of 95 consecutive patients underwent laparoscopic RP for clinically localized prostate cancer (PC) by an experienced single surgeon from October 2009 to December 2012. Baseline characteristics, perioperative and pathologic variables, and continence data at 3 months after surgery were retrospectively reviewed from a prospectively maintained database. Categoric and continuous variables were compared using chi-square, Student t, and Wilcoxon rank-sum tests, as appropriate.

Results:

A total of 29 patients underwent laparoscopic RP using a 3D display system and 66 patients underwent laparoscopic RP using a 2D display system. The two groups were comparable for all clinical and pathologic variables. Mean total operative time for the 3D group was 131 minutes (standard deviation [SD]±18) compared with 190 (SD±31) for the 2D group (P<0.001). Mean time to perform the urethrovesical anastomosis was 28 minutes (SD±6) for the 3D group compared with 87 minutes (SD±17) for the 2D group (P<0.001). Blood loss was lower in the 3D group, and the difference was statistically significant (P<0.001). A statistically significant higher number of patients in the 3D group had early recovery of continence compared with patients in the 2D group (14/28 (50%) patients in the 3D group vs 16/64 (25%) patients in the 2D group, P=0.02).

Conclusions:

Laparoscopic RP aided by a new-generation 3D display system is associated with shorter operative times, reduced blood loss, and higher early continence rates in comparison with that aided by a 2D display system. In particular when considering economic issues, 3D laparoscopic RP may represent an acceptable alternative to robot-assisted laparoscopic RP.

Introduction

Radical prostatectomy (RP) remains the reference standard for the surgical management of clinically localized prostate cancer (PC).^1,2 Since Hugh Hampton Young's first description of radical perineal prostatectomy in 1905,³ substantial efforts have been devoted to improving anatomic knowledge and surgical techniques to optimize the perioperative course as well as oncologic and functional outcomes. In this context, minimally invasive approaches including conventional and robot-assisted laparoscopic RP have gained increasing interest in recent years. In fact, early available evidence indicates that comparable results can be achieved with open, conventional, and robot-assisted RP in terms of perioperative, oncologic, and functional outcomes.^4,5

Conventional laparoscopic RP was first introduced in 1991.⁶ Despite known advantages that include less postoperative pain and shorter hospital stay, laparoscopic RP is a complex procedure that is limited by two-dimensional (2D) visualization and space constraint. The operation is therefore associated with a long learning curve.⁷ Some of these limitations have been overcome with the introduction of robotic technology, which provides three-dimensional (3D) display in addition to endowristed instrumentation. Robotic technology, however, is associated with a substantially higher initial investment as well as running costs and particularly in low-volume centers is not cost-effective.^8,9 On the other hand, a 3D display system represents an alternative at reduced cost to improve on one of the important limitations of conventional laparoscopy—i.e., depth perception and spatial orientation.

To the best of our knowledge, there is no published comparative study between 2D and 3D display systems for laparoscopic RP. To redress this lack, the present study aims to compare perioperative, pathologic, and early continence outcomes between laparoscopic RP aided by a next-generation 3D display system and a conventional 2D display system in a series of 95 consecutive patients.

Patients and Methods

The study protocol was reviewed and approved by the Institutional Review Board. From October 2009 to December 2012, 95 consecutive patients with clinically localized PC underwent laparoscopic RP by a single surgeon (SA) who had performed more than 600 laparoscopic interventions before study start, including approximately 100 laparoscopic RPs, using an extraperitoneal, antegrade technique.¹⁰ The 3D display system was 3DHD Vision System^® (Viking Systems, La Jolla, CA), while the 2D display system was Full HD Endoscopy System^® (Karl Storz, Tuttlingen, Germany). Because the 3D display system was available from April 2010 and because it is shared with other units in our hospital, the choice of use of the 3D or 2D system was based on its availability on the day of surgery. No demographic, clinical, or oncologic criteria were used to select the visualization system.

Briefly, the laparoscopic RP follows these steps: Development of the extraperitoneal space, transection of the bladder neck, dissection of the periprostatic fascia (and of the endopelvic fascia in case of nerve sparing) toward the apex of the prostate, dissection of the vasa deferentia and seminal vesicles to the level of the Denonvilliers fascia, ligation of the dorsal venous complex (DVC), and transection of the apical urethra and DVC. Bilateral pelvic lymph node dissection is performed if the preoperative serum prostate-specific antigen (PSA) level is >10 ng/mL and/or Gleason score >7.

The urethrovesical anastomosis is accomplished with a V-Loc™ 180 Absorbable Wound Closure Device (Covidien, Paris, France). Starting at 3 o'clock, the anastomosis is completed using a running suture technique after introduction of a 20F Foley catheter into the bladder. Anastomotic integrity is confirmed by filling the bladder with 150 mL of saline and checking for leak. Rectal injury is checked in all patients by gently inserting a rectal tube and blowing air in the rectum after covering it with saline. A drain is placed at the anastomosis. In both groups, attempts to preserve the neurovascular bundles are made in patients with cT_1c-T_2a PC, serum PSA level <10 ng/mL, Gleason score 6, and erections before surgery.

After surgery, all patients are mobilized within 24 hours of surgery. The patients are allowed oral intake within 24 to 48 hours depending on intestinal activity. The drain is taken out when it shows no significant output. Patients are discharged 1 day after removal of the drain contingent on adequate pain control, oral intake, ambulation, and flatus. The Foley catheter is routinely removed at 15 days after surgery.

All clinical, perioperative, and pathologic variables were evaluated retrospectively from a prospectively maintained database. Baseline characteristics included age at RP, body mass index (BMI), American Society of Anesthesiologists (ASA) score, serum PSA level at RP, and biopsy Gleason score. Perioperative variables were total operative time (from Hasson incision to removal of prostate specimen), time to perform the urethrovesical anastomosis, blood loss, and complications adapted from the Dindo-Clavien classification system.¹¹ Pathologic variables included prostate specimen weight, tumor stage according to the 2002 tumor-node-metastasis classification, pathologic Gleason score, and presence of positive surgical margins (PSMs). In addition, early continence data at 3 months after surgery were assessed, with continence defined as the use of 1 safety pad or less per day.

Parametric and nonparametric continuous variables were reported as the mean (standard deviation [SD]) and the median (range), respectively. Differences in clinical, perioperative, and pathologic variables were assessed with the chi-square test for categorical variables and the Student t test (means) and Wilcoxon rank-sum test (medians) for continuous variables, using IBM SPSS 21 (IBM, Armonk, New York, NY). A two-sided P value<0.05 was considered significant.

Results

In all, 29 patients underwent laparoscopic RP using a 3D display system and 66 patients underwent laparoscopic RP using a 2D display system. There was no statistically significant difference between both groups with regard to age at RP, BMI, ASA score, serum PSA level at RP, and biopsy Gleason score (Table 1). Similarly, prostate specimen weight, distribution of pathologic tumor stage, and pathologic Gleason score and presence of PSMs were comparable in both groups (Table 1). There were statistically significant differences in total operative time and time to perform the urethrovesical anastomosis. Mean total operative time for the 3D group was 131 minutes (±18) compared with 190 (±31) for the 2D group (P<0.001) (Table 2). Mean time to perform the urethrovesical anastomosis was 28 minutes (±6) for the 3D group compared with 87 (±17) for the 2D group (P<0.001). Blood loss was lower in the 3D group and the difference was statistically significant (102 mL (±17) for the 3D group vs 138 (±32) for the 2D group, P<0.001).

Table 1.

Baseline Characteristics of the Study Population

	3D group n=29	2D group n=66	P-value
Age at RP, median (range)	65 (49–73)	64.5 (46–78)	0.5
BMI (kg/m²), median (range)	31 (25–35)	30.5 (24–37)	0.9
ASA score, median (range)	2 (1–3)	2 (1–3)	0.1
PSA (ng/mL), median (range)	7.6 (4.0–23.0)	6.0 (2.3–34.7)	0.8
Biopsy Gleason score, n (%)
≤6	21 (72)	51 (77)	0.8
7	7 (24)	14 (21)
≥8	1 (3)	1 (2)
Lymph node dissection, n (%)	16 (55)	35 (53)	0.9
Prostate specimen weight (g), median (range)	55 (30–99)	51.5 (20–140)	0.5
Pathologic tumor stage, n (%)
T₂	24 (83)	51 (77)	0.6
T₃	5 (17)	14 (21)
T₄	0	1 (2)
Pathologic Gleason score, n (%)
≤6	7 (24)	23 (35)	0.2
7	14 (48)	34 (52)
≥8	8 (28)	9 (14)
PSM, n (%)	4 (14)	11 (17)	0.8

3D=three-dimensional; 2D=two-dimensional; RP=radical prostatectomy; BMI=body mass index; ASA=American Society of Anesthesiologists; PSA=prostate-specific antigen; PSM=positive surgical margin. Percentages may not sum because of rounding.

Table 2.

Perioperative Outcomes of Patients Who Underwent Laparoscopic Radical Prostatectomy Aided by Three-Dimensional and Two-Dimensional Display Systems

	3D group n=29	2D group n=72	P-value
Operative time (min), mean (SD)	131 (±18)	190 (±31)	<0.001
Anastomosis time (min), mean (SD)	28 (±6)	87 (±17)	<0.001
Blood loss (mL), mean (SD)	102 (±17)	138 (±32)	<0.001

3D=three-dimensional; 2D=two-dimensional; SD=standard deviation.

Intraoperative anastomotic leakage could not be detected in any patients. Three patients suffered minor rectal tears during surgery, all in the 2D group. These tears were primarily repaired in two layers. These complications had no impact on the postoperative course and recovery of the patients. There were no conversions to open surgery. Blood transfusion was needed postoperatively in a single patient, who belonged to the 2D group. There were no early postoperative complications including pneumonia, wound infection, deep venous thrombosis, or lymphocele.

Data on continence status at 3 months after surgery were available in 92/95 (97%) patients. A statistically significant higher number of patients in the 3D group had early recovery of continence compared with patients in the 2D group (14/28 [50%] patients in the 3D group vs 16/64 [25%] patients in the 2D group, P=0.02).

Discussion

New-generation 3D display systems aim to fill the gap between conventional 2D display systems and robotic technology. We show for the first time that laparoscopic RP aided by a next-generation 3D display system is superior to that aided by a 2D display system in regard to total operative time, time to perform the urethrovesical anastomosis, blood loss, and early continence outcomes.

In 1992, 3D visualization was introduced in laparoscopy with the hope of improving depth perception and spatial orientation, thereby enhancing surgical performance and reducing learning curves.¹² Reviews of early commercially available 3D display systems were mixed, however. While some general surgeons found that 3D vision improved surgical performance on surgical trainers or animals,^13

–16 others did not.^17
–19 These first- and second-generation 3D display systems were limited by reduced resolution compared with three-chip 2D systems,⁷ dimmer illumination, and blurred peripheral display that caused symptoms of ocular fatigue, headache, and nausea.^17
–19 One randomized clinical study in 1998 found no difference between 3D and 2D display systems for laparoscopic cholecystectomy in regard to operative time, error rate, and surgeons' side effects.²⁰

Gains in surgical performance between 3D and 2D display systems, however, have not been evaluated for more complex procedures, where the utility of 3D visualization may be more apparent. In recent years, the shortcomings of earlier 3D display systems as well as improvement in video imaging have led to the development of new-generation visualization systems and a renewed interest in 3D laparoscopic surgery.²¹

The 3DHD Vision System has been examined in surgical, nonurologic settings. Tanagho and associates²² evaluated surgical skills and task performance using Viking's 3D system or a 2D display system. Simple and complex tasks took significantly longer to complete with the 2D than with the 3D display system, and 87.9% of all participants preferred 3D visualization. The same group reported that initial clinical results were encouraging.²³ Bilgen and colleagues²⁴ compared the 3DHD Vision System to Olympus 2DHD System^® (Olympus Corporation, Tokyo, Japan) in 22 patients who underwent laparoscopic cholecystectomy (11 patients in each arm). The authors reported statistically shorter operative times in favor of the 3D display system (20 min vs 30 min).²⁴ In line with these findings, studies using other modern 3D display systems reported that these novel modalities can improve the performance of laparoscopic surgeons.^25

–29 Taken together, these studies and ours support a role for modern 3D visualization in enhancing surgical performance regardless of surgical experience.

Improved spherical optics during surgery allows the surgeon to accurately determine spatial distance and improve hand-eye coordination,⁷ thereby enhancing dissection, grasping skills, suturing, and overall surgical efficiency. Regarding operative times, our results suggest that improvements are mainly attributed to the facilitation of the urethrovesical anastomosis, usually considered the most challenging and time-consuming step of laparoscopic RP.³⁰ Our operative times with the 3D display system are in line with those from experienced robot-experienced groups (Menon and coworkers,³¹ 154 min; Patel and colleagues,³² 130 min; Frota and associates,³³ 199 min). Our mean time to perform the urethrovesical anastomosis is slightly longer (Rassweiler and colleagues,⁷ 16 min [range 12–22], Menon and associates,³⁴ 13 min [5–34]). Similarly, reduced blood loss may be attributed to the magnified 3D continence outcomes imaging, which allows the surgeon to perform more delicate and accurate maneuvers.

In the context of laparoscopic RP, depth perception is critical to adequate hemostasis and suturing of the urethrovesical anastomosis. On the other hand, the rate of PSMs was similar between the 3D and 2D groups. Although lower PSM rates may have been expected in the 3D group, our single-surgeon study was most likely insufficiently powered to capture any difference. Interestingly, our overall PSM rate regardless of the visualization system (15.8%) is lower than reported numbers for laparoscopic RP (20.4%); however, it is in line with PSM rates in robot-assisted laparoscopic RP (16.2%).³⁵ Furthermore, early continence outcomes showed that the use of 3D visualization in our patients led to higher continence rates at 3 months after surgery, an achievement possibly owed to better preservation of structures around the urinary sphincter, improved apical dissection, and preservation of the neurovascular bundles.⁷

One other advantage of modern 3D technology is the considerable reduction of side effects.¹⁴ Instead of a cumbersome head mounted display, the operating team wears 3D glasses similar to sunglasses (Fig. 1). Of note, the present 3D display system is available at approximately $150,000, with no additional consumable expenses, while the Da Vinci S Surgical System (Intuitive Surgical Inc., Sunnyvale, CA) costs around $1.5 million. Therefore, we argue that 3D laparoscopic RP represents an acceptable alternative to robot-assisted laparoscopic RP, especially in low-volume centers like ours.

FIG. 1.

Three-dimensional glasses used with the 3DHD Vision System.

The main limitation of our study is the lack of randomization allocation of the patients to the study arms. On availability of the 3D system in our hospital, however, the choice of the visualization system was based on accessibility of the 3D system on the day of surgery. No demographic, clinical, or oncologic criteria were used to select the visualization system. Moreover, our two groups are similar in terms of baseline characteristics. Therefore, we believe that selection and comparison bias are minimal and that the present study provides a realistic perspective of daily clinical practice. At the same time, our results need to be interpreted with caution given the low number of cases, which does not convey statistical certainty.

Another shortcoming of our study is that our cohort has to mature to determine potential advantages of 3D over 2D laparoscopic RP in regard to long-term functional and oncologic outcomes. Further studies aimed at addressing these questions are needed. Finally, a laparoscopically experienced surgeon undertook all present surgeries. It remains to be documented whether extension of 3D visualization to laparoscopically untrained surgeons will shorten the learning curve of laparoscopic RP. Previous studies on laparoscopic trainers suggest that 3D vision is beneficial to both untrained and experienced surgeons. ^{13,22,25,27,28} These limitations notwithstanding, we show for the first time that new-generation 3D laparoscopic RP is associated with shorter operative times, reduced blood loss, and higher early continence rates in comparison with conventional 2D laparoscopic RP. In view of the growing popularity of robot-assisted laparoscopic RP, our findings are important not only to urologists, but also to healthcare providers as a whole when considering economic issues.

Conclusions

Laparoscopic RP aided by new-generation 3D vision is associated with shorter operative times, reduced blood loss, and higher early continence rates in comparison with that aided by 2D vision. This novel technique holds great potential as an alternative to robot-assisted laparoscopic RP. Further validation of 3D laparoscopic RP in larger cohorts and, ideally, prospective comparison with robot-assisted laparoscopic RP are warranted.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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Perioperative,Pathologic,and Early Continence Outcomes Comparing Three-Dimensional and Two-Dimensional Display Systems for Laparoscopic Radical Prostatectomy—A Retrospective,Single-Surgeon Study

Abstract

Purpose:

Patients and Methods:

Results:

Conclusions:

Introduction

Patients and Methods

Results

Discussion

Conclusions

Footnotes

Disclosure Statement

Abbreviations Used

References