Control Comparison of the New EndoWrist and Traditional Laparoscopic Staplers for Anterior Rectal Resection with the Da Vinci Xi: A Case Study

Abstract

Background:

A new robotic stapler for the da Vinci Xi^® is directly controlled by the surgeon at the console and equipped with EndoWrist^® technology. We evaluated operative and short-term results of the first patients who underwent anterior rectal resection for cancer with the da Vinci Xi and new staplers, and compared the results with those of a comparable group treated with traditional laparoscopic staplers.

Methods:

From December 2015 to December 2017, 25 patients underwent anterior rectal resection for cancer with robotic EndoWrist staplers (EndoWrist group). Using a case–control method, we compared the results with those of a similar group of patients treated with the same system and a traditional laparoscopic endostapler, controlled by a bedside assistant (Control group).

Results:

No conversions to laparoscopy or laparotomy were observed, in either group. The mean number of charges was 2.1 ± 0.2 in the EndoWrist group versus 2.7 ± 0.7 in the Control group (P = .0004). The other perioperative results were comparable. During follow-up, the incidence of anastomotic fistula in a contrast enema study was higher in the Control group, although the difference was not statistically significant (two leaks versus two leaks in EndoWrist group; P = .8). The interval between rectal resection and stoma closure was shorter in the EndoWrist group (3.4 ± 2.5 versus 4.2 ± 2.9 months in the Control group; P = .2), although the difference was not significant.

Conclusions:

Our experience suggests that the new robotic staplers simplify transection, which could reduce the average number of stapler firings used during rectal resection and could decrease the incidence of anastomotic leakage. These findings require confirmation in larger studies.

Introduction

Robotic surgery for rectal cancer was first described by Pigazzi et al.,¹ in 2006. Since then, uptake of the da Vinci Si anterior rectal resection has been rapid. Accumulating evidence suggests that this system has perioperative and functional advantages over laparoscopic approaches and results in similar oncologic outcomes.^2,3

Some intrinsic limitations of this platform have been addressed by a new product, the da Vinci Xi^®, which was specifically designed for multiquadrant surgery. In addition, the da Vinci Xi is particularly suitable for colorectal procedures.⁴ However, despite recent technological innovations, an important phase of the operation—distal rectal transection—until recently, required the aid of pure laparoscopy and the use of a laparoscopic linear articulated stapler by a bedside surgeon. This was relatively challenging because of the unfavorable entry angle from the assistant port and because of the width and limited range of motion for traditional staplers in the narrow pelvis.

The EndoWrist^® Stapler (Intuitive Surgical, Sunnyvale, CA) for the da Vinci Xi Surgical System enables full control of stapling by a surgeon at the robotic console. Moreover, this device has a special articulation system with a total side-to-side range of 108° and a total up-and-down range of 54°, thus providing a fully wristed cone of articulation. In addition, Smart Clamp Feedback reduces guesswork associated with conventional, handheld stapling by detecting whether the jaws of the device can adequately close on target tissue at a given staple height.

We analyzed the operative results and short-term outcomes for the first patients at our center to undergo robotic low anterior rectal resection with total mesorectal excision (TME) for cancer with the use of the new robotic staplers for the da Vinci Xi and compared those findings with the results from a control group treated with traditional laparoscopic staplers.

Materials and Methods

From December 2015 to December 2017, 25 patients with histologically confirmed rectal cancer underwent robot-assisted anterior rectal resection with TME with the new robotic 45 mm stapler for the da Vinci Xi at our Multidisciplinary Center of Robotic Surgery (EndoWrist group). Preoperative patient characteristics were recorded, including data from a colonoscopy with biopsy, endorectal ultrasonography, magnetic resonance imaging, and computed tomography. Patients with cT3, or node-positive disease, received preoperative chemoradiotherapy, in accordance with current oncologic guidelines. For these patients, the operation was performed 6–8 weeks after the end of radiation treatment.

Exclusion criteria for robotic surgery were preoperative diagnosis of T4 tumors invading the vagina, uterus, prostate, seminal vesicles, or bladder, a history of major lower abdominal surgery, and contraindications to anesthesia. The outcomes of the EndoWrist group were compared with those of a control group selected from patients undergoing da Vinci Xi robotic TME rectal resection with a traditional laparoscopic stapler (Endopath Echelon 60 mm or Endo GIA Roticulator Covidien 60 mm; Control group) at our center.

Patients were selected using a one-to-one case-matched design, where each patient in the EndoWrist group was matched with a patient in the Control group according to age, sex, body mass index, American Society of Anesthesiologists score, neoadjuvant chemoradiotherapy status, and distance of the distal tumor margin from the anal verge.

Perioperative data were analyzed and included overall operative time (from creation of pneumoperitoneum to application of dressing), docking time, whether the splenic flexure was mobilized, number of stapler charges necessary for rectal transection, and conversion rate to other surgical techniques. Postoperative data included duration of hospital stay, morbidity, mortality, symptomatic and asymptomatic anastomotic leak (AL) rates, readmission rate, and interval from rectal resection to stoma closure.

Abdominal pain, fever, pus, or fecal discharge from the pelvic drain, peritonitis, and pelvic abscess were regarded as signs of clinical leakage. Clinically suspicious symptoms were confirmed by radiographic examination (e.g., extravasation of endoluminally administered water-soluble contrast enema, abscess at the level of anastomosis, and fluid/air bubbles surrounding the anastomosis on computed tomography images). Every patient underwent a routine water-soluble contrast enema study 1 month after surgery, to detect possible asymptomatic anastomotic fistulas path and to plan stoma closure. The number of harvested lymph nodes, margin status and, most importantly, the distance of the distal tumor margin from the anal verge were also measured and recorded.

Differences between groups were analyzed with the independent t-test or Pearson chi-square test, as appropriate. A P-value of <.05 was set as the threshold for statistical significance. All patients received an extensive explanation of the procedure and provided informed consent. The study was approved by the Institutional Review Board.

Surgical technique

All patients received standard bowel preparation and antibiotic prophylaxis. Single docking full robotic technique was used for both groups. Patients were placed in a modified lithotomy position with a 30° Trendelenburg angle and a tilt to the right side. The first 8-mm robotic trocar was placed in the umbilical region, along the right pararectal line. Four trocars were then inserted in an oblique fashion under visualization, in accordance with the “modified” universal port placement guidelines provided by Intuitive Surgical for “left lower” abdominal procedures, as described elsewhere.⁴ “Patient-left” was the selected approach, and the surgical cart was moved to position the green laser crosshairs on the initial endoscope port.

After docking, the scope was pointed at the inferior mesenteric pedicle of the sigmoid colon, and the “targeting” function was performed. The boom was then rotated in a clockwise direction to ensure the optimal configuration for dividing the inferior mesenteric pedicles and mobilizing the left colon until the splenic flexure. After mobilization of the left colon, proctectomy with TME was performed with nerve-sparing technique. To perform this last phase, we only used the “FLEX” function to change the arm orientation toward the pelvis; we did not perform retargeting.

In the Control group, the rectum was then transected with a traditional laparoscopic stapler, fired by an assistant at the operating table through the accessory 12-mm port in the right iliac fossa, which is considerably higher than the line for the robotic trocars. In the EndoWrist group we used the new robotic EndoWrist stapler, green cartridge, inserted in a specific 12-mm robotic trocar, which replaced the standard 8-mm robotic trocar situated in the right lower quadrant.

After the surgical specimens were removed through suprapubic minilaparotomy, the anvil of a circular stapler was positioned in the proximal colon. The circular stapler (CDH20; Ethicon Endo-Surgery, Cincinnati, OH) was inserted through the rectum, after which end-to-end double-stapling anastomosis was completed intracorporeally. The “doughnut” created after anastomosis was inspected for completeness. Airtightness was routinely tested by transanal instillation of air. At the end of the procedure, the surgeon decided whether to fashion a diverting ileostomy in the right flank.

Results

The baseline characteristics of the matched patient groups are summarized in Table 1.

Table 1.

Baseline Characteristics

	EndoWrist (n = 25)	Control (n = 25)	P-value
Male (%)	18 (72)	17 (68)	.9
Age (years), mean ± SD	67.1 ± 12.2	68.1 ± 10.5	.4
BMI, mean ± SD	25.8 ± 1.8	26.5 ± 2.6	.15
ASA score 3 or 4 (%)	13 (53)	15 (60)	.5
Low rectum location (%)	11 (44)	10 (40)	.95
Distance from anal verge (cm), mean ± SD	7.1 ± 3.7	7.2 ± 3.4	.5
Neoadjuvant therapy (%)	9 (36)	8 (32)	.8

ASA, American Society of Anesthesiologists; BMI, body mass index; SD, standard deviation.

From an intraoperative standpoint, we performed full-robotic complete takedown of the splenic flexure in both study groups. There was no conversion to conventional laparoscopy, hand-assisted laparoscopy surgery, or open surgery in either group. No intraoperative surgical complications developed and no additional trocars were required in any patient. There was no significant difference in mean operative time (302.1 ± 61.1 min in the EndoWrist group versus 284.0 ± 57.6 min in the Control group, P = .16). Even mean docking time was similar between groups. The number of stapler firings required was significantly higher for the Control group than for the EndoWrist group (2.7 ± 0.7 versus 2.1 ± 0.2, respectively; P = .0004; Table 2). A diverting stoma was created in 23/25 patients in the EndoWrist group and 22/25 patients in the Control group.

Table 2.

Perioperative Records Between the Two Study Groups

	EndoWrist (n = 25)	Control (n = 25)	P-value
Totally da Vinci Xi anterior rectal resection (%)	25 (100)	25 (100)	.99
Complete splenic flexure mobilization (%)	25 (100)	25 (100)	.99
Conversion to laparoscopy or open (%)	0 (0)	0 (0)	.99
Operative time (minutes), mean ± SD	302.1 ± 61.1	284.0 ± 57.6	.16
Docking time (minutes), mean ± SD	21.7 ± 5.8	21.2 ± 5.3	.9
No. stapler firing, mean ± SD	2.1 ± 0.2	2.7 ± 0.7	.0004
Ileostomy (%)	23 (92)	22 (88)	.9
Distal margin (mm), mean ± SD	25.2 ± 10.4	22.1 ± 15.4	.2
No. lymph nodes, mean ± SD	23.5 ± 12.1	20.3 ± 5.4	.09
Postoperative hospital stay (days), mean ± SD	7.8 ± 2.9	7.2 ± 2.6	.2
Postoperative minor surgical complications (%)	3 (12)	4 (16)	.5
Anastomotic leak (%)	2 (8)	3 (12)	.8
Time between primary surgery and stoma reversal (month), mean ± SD	3.4 ± 2.5	4.2 ± 2.8	.2

SD, standard deviation.

There were no significant differences between groups in the distal margin (25.2 ± 10.4 mm in the EndoWrist group versus 22.1 ± 15.4 mm in the Control group; P = .2) or mean number of retrieved lymph nodes (23.5 ± 12.1 versus 20.3 ± 5.4, respectively; P = .09). No patients had involvement of circumferential resection margins (≤1 mm), and the quality of the mesorectum, according to Quirke's criteria,⁵ was classified as “complete” in all cases.

There were no reoperations or in-hospital deaths. Only one patient in the Control group developed symptomatic AL with fever and fluid collection with air bubbles surrounding the anastomosis, which was revealed by computed tomography. The patient was treated conservatively, which resulted in complete clinical resolution, and was followed up with contrast enema studies, clinical evaluations, and blood testing after discharge. Minor complications occurred in three patients in the EndoWrist group and in four patients in the Control group (P = .5). However, most (5/7 cases; 71% of total) of these complications were related to ileostomy outflow and were treated with supportive therapy. The average hospital stay was similar between groups (7.8 ± 2.9 days in the EndoWrist group versus 7.2 ± 2.6 days in the Control group; P = .2).

During the follow-up period, the overall incidence of anastomotic fistula was higher in the Control group in a contrast enema study, although the difference was not significant (two cases of asymptomatic plus one case of symptomatic AL in the Control group versus two cases of asymptomatic AL in the EndoWrist group; P = .8). The interval from rectal resection to stoma closure was shorter in the EndoWrist group than in the Control (3.4 ± 2.5 versus 4.2 ± 2.8 months, respectively; P = .2), although the difference was significant.

Discussion

The double-stapling technique⁶ has simplified intestinal reconstruction, particularly after operations for rectal cancer. The advent of mechanical stapling devices and ongoing instrument development has simplified reconstruction of the distal rectum. Despite these improvements, AL remains an important complication of this type of surgery, as it adversely affects early postoperative outcomes and is associated with local recurrence and survival.^7,8

The creation of a diverting stoma, despite the lack of consensus on its effects on AL incidence,⁹ can prevent the clinical sequelae of AL, including peritonitis, abscess, and septicemia.¹⁰ However, asymptomatic leakage prolongs the interval from primary rectal resection to reoperation for stoma reversal; this is particularly important for patient quality of life in light of potential psychological and stoma-related problems.¹¹ Moreover, stoma-related problems may alter the “window of opportunity” for adjuvant chemotherapy, which is important for reducing the risk of cancer recurrence.

As compared with open surgery, minimally invasive surgical approaches for large bowel resection in the treatment of malignant colon disease have many advantages, the most important of which are earlier recovery and reduced postoperative pain.^12,13 The anastomotic fistula rate after proctectomy is similar for laparoscopic and robotic procedures: 3%–20%.^14–16

Several factors have been extensively examined in relation to their association with AL risk,^14,17,18 including male sex, body mass index, history of neoadjuvant radiotherapy, bowel preparation, preoperative antibiotic regimen, and the level and characteristics of the primary rectal tumor. However, variables related to intraoperative risk appeared to be the most relevant. In particular, studies indicate that use of more than three cartridges for distal rectal transection is an important cause of leakage, because of the presence of small defects between staple lines. Other factors that might be important in achieving secure stump formation are the crossing points of staple lines, precompression, proper cartridge selection, blood supply, operative time, and anastomotic tension.

A recent study¹⁹ reported that, as compared with AL during traditional operations, AL during minimally invasive rectal resection was more strongly associated with factors related to technical difficulties, such as sex (narrower pelvis, visceral obesity), previous abdominal operations, low anterior resection, operative time, and, most importantly, the number of stapler firings.

In rectal surgery, standard laparoscopy has obvious limits, particularly for proctectomy in the deep pelvis, because of the bi-dimensional view and use of straight instruments. Thus, laparoscopic anterior rectal resection is considered a challenging operation with a high conversion and should be performed by expert surgeons at high-volume centers.²⁰

The enhanced dexterity and stable 3-HD camera offered by robotic assistance can potentially overcome the intrinsic drawbacks of laparoscopy when working in narrow spaces. Previous studies found that da Vinci Si rectal resection improved functional and perioperative outcomes, particularly for “difficult cases,” such as obese patients and male patients with restricted operative fields.^21,22

In contrast, the previous version of the Intuitive robot was criticized for its bulky side cart, and because the limited range of motion increased operative time and the workflow of operations, particularly when coverage of a wide surgical area was required.

The da Vinci Xi has several tools and specific characteristics that make it well suited for multiquadrant surgery and thus for rectal surgical procedures such as proctectomy, high inferior mesenteric vessel ligation, and left colonic mobilization. A recent study²³ noted a significant reduction in operative time and full splenic mobilization with tension-free anastomosis during da Vinci Xi rectal resection as compared with da Vinci Si rectal resection. These findings are very important for AL, as it is generally believed that the splenic flexure must be sufficiently mobilized to lower anastomotic tension, especially when the anastomotic site is very low.

In addition, the new operating table enables the patient to be repositioned without undocking the robot, thus offering one of the advantages of laparoscopy, that is, rapid, flexible use of gravity for countertraction.²⁴ The ability to move the patient quickly during robotic surgery drastically reduces operative time and simplifies all phases of rectal resection.

Moreover, the Fire-Fly^®, a smart, user-friendly indocyanine fluorescence program, appears to be particularly useful for real-time evaluation of stump perfusion, which is important in suture sealing. Some recent data^25,26 indicate that fluorescence imaging changed the initially planned transection line in 13.9% of cases and reduced AL by 4%, as compared with a control group.

Nevertheless, during the distal transection phase even robot-assisted rectal resection inevitably requires the aid of laparoscopy and/or use of a laparoscopic linear stapler, which is more difficult than open surgery. This is a critical step because of the width and limited performance of a standard linear stapler in the pelvic cavity and because of problems related to the need for one-handed manual firing by an assistant at the operating table. These limitations may in part explain the similar AL findings for robot-assisted and total laparoscopic rectal resection.¹⁶

The EndoWrist Stapler for the da Vinci Xi surgical system enables the operating surgeon at the console to control stapling, which creates a more direct relationship between clinical decision making and instrument action. This is particularly important, as it transforms, in this setting, the entire procedure for full-robotic, full-automated rectal resection. The stapler line appeared to be more rectilinear in the EndoWrist group.

In our experience, and with difficult cases, the sharp dissection and full rectal mobilization provided by the robot in combination with this new stapler device improved the ease and precision of distal transection. Interestingly, the total number of firings was less than the threshold of three cartridges in all patients that underwent procedures using a robotic stapler.

This reduced AL incidence as compared with the traditional laparoscopic stapler, although the difference was not significant. A large proportion of patients with AL were asymptomatic, and AL was discovered in a postoperative contrast enema study of an ileostomy. Despite the lower incidence of major surgical complications, rectal fistula affects recanalization time. In the present study, the mean interval from primary surgery to ileostomy was shorter in the EndoWrist group than in the Control group (3.4 versus 4.2 months, respectively), because of the lower AL incidence in the former.

This study had some limitations. The retrospective design of the study may have resulted in selection bias; however, the use of case matching ensured that the two groups were homogeneous and would tend to reduce differences in preoperative AL risk between groups. In addition, in both groups, rectal resection was performed with the aid of da Vinci Xi and thus the splenic flexure mobilization rate was similar. This eliminated the inconvenience of using different robotic platforms and surgical techniques and resulted in distal transection being the only variable. The small sample size is another drawback that precludes us from offering definitive conclusions.

To date only two studies have been published on the use of the new EndoWrist robotic staplers in the field of colorectal surgery. If the published article by Holzmacher et al.²⁷ contains a heterogeneous patient population regarding surgical interventions and primary diseases, the most recent article of Atasoy et al.²⁸ encloses a relatively restricted and homogeneous case cohort. The authors showed no difference between robotic and laparoscopic stapler in terms of stapler firing and fistula rate, but because the two groups were not similar as in the robotic stapler group, and a greater number of male patients was present, the reported results could be affected by a selection bias.

Even if our study had some limitations, such as the retrospective design and the small sample size, the use of case matching ensured that the two groups were homogeneous and would tend to reduce differences in preoperative AL risk between groups. In addition, in both groups, rectal resection was performed with the aid of da Vinci Xi and thus the splenic flexure mobilization rate was similar. This eliminated the inconvenience of using different robotic platforms and surgical techniques and resulted in distal transection being the only variable.

In conclusion, the EndoWrist robotic stapler permits a safe resection, as it is fully automated and totally controlled by the operator. This allows rectal resection to be performed with complete robot assistance, without the intrinsic limits of a laparoscopic phase and the use of manual laparoscopic devices. Our experience indicates that the new robotic linear staplers have intraoperative advantages, namely fewer stapler firings during rectal resection and a trend toward fewer anastomotic fistulas. Because of the lower incidence of AL, the mean interval from rectal surgery to stoma reversal was slightly shorter in the EndoWrist group, which had a beneficial effect on short-term outcomes. These findings are encouraging but require confirmation in larger studies.

Footnotes

Acknowledgment

The study was supported by ARPA Foundation:

Disclosure Statement

No competing financial interests exist.

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