Novel prototype sewing device, EndoSew®, for minimally invasive surgery: an extracorporeal ileal conduit construction pilot study in 10 patients

Authors


  • B.R. and F.D.B. contributed equally to the work.
  • Trial registration: ClinicalTrials.gov; ISRCTN65809197.

Correspondence: Pascal Zehnder, Department of Urology, University of Bern, CH-3010 Bern, Switzerland.

e-mail: urology_berne@insel.ch

Abstract

What's known on the subject? and What does the study add?

  • The EndoSew® prototype was first tested in a porcine model several years ago. The investigators found it both simple to master and reliable, its greatest advantage being a 2.4-fold time saving compared with straight laparoscopic suturing. In addition to that publication, there is a single case report describing the performance of an open EndoSew® suture to close parts (16 cm) of an ileal neobladder. The time for suturing the 16 cm ileum was 25 min, which is in line with our experience. The knowledge on this subject is limited to these two publications.
  • We report on the first consecutive series of ileal conduits performed in humans using the novel prototype sewing device EndoSew®. The study shows that the beginning and the end of the suture process represent the critical procedural steps. It also shows that, overall, the prototype sewing machine has the potential to facilitate the intracorporeal suturing required in reconstructive urology for construction of urinary diversions.

Objective

  • To evaluate the feasibility and safety of the novel prototype sewing device EndoSew® in placing an extracorporeal resorbable running suture for ileal conduits.

Patients and Methods

  • We conducted a prospective single-centre pilot study of 10 consecutive patients undergoing ileal conduit, in whom the proximal end of the ileal conduit was closed extracorporeally using an EndoSew® running suture.
  • The primary endpoint was the safety of the device and the feasibility of the sewing procedure which was defined as a complete watertight running suture line accomplished by EndoSew® only. Watertightness was assessed using methylene blue intraoperatively and by loopography on postoperative days 7 and 14.
  • Secondary endpoints were the time requirements and complications ≤30 days after surgery.

Results

  • A complete EndoSew® running suture was feasible in nine patients; the suture had to be abandoned in one patient because of mechanical failure.
  • In three patients, two additional single freehand stitches were needed to anchor the thread and to seal tiny leaks. Consequently, all suture lines in 6/10 patients were watertight with EndoSew® suturing alone and in 10/10 patients after additional freehand stitches.
  • The median (range) sewing time was 5.5 (3–10) min and the median (range) suture length was 4.5 (2–5.5) cm.
  • There were no suture-related complications.

Conclusions

  • The EndoSew® procedure is both feasible and safe.
  • After additional freehand stitches in four patients all sutures were watertight.
  • With further technical refinements, EndoSew® has the potential to facilitate the intracorporeal construction of urinary diversions.

Introduction

Robot-assisted radical cystectomy is rapidly evolving [1-6]. Complex intracorporeal manipulations, such as the entire construction of a urinary diversion, require higher skill levels and are more time-consuming than extracorporeal manoeuvres [7]. Urinary diversions after robot-assisted radical cystectomy, therefore, are usually performed via mini-laparotomy [8], facilitating bowel preparation, resection and freehand extracorporeal reconstructive suturing. The switch to the open approach minimizes the potential advantages of diversions performed purely intracorporeally. In the past, new devices, such as laparoscopic staplers, were developed to facilitate the construction of urinary diversions [9, 10]. The use of non-absorbable staples, however, remains a risk for stone formation if the staples come in contact with urine [11, 12], leading to complications such as chronic urinary infections [13]. Mechanical sewing devices using resorbable suture material would simplify the demanding sewing part of reconstructive urological surgery and decrease potential complications. Recently, a novel prototype sewing device for laparoscopic use, the EndoSew®, was introduced in a pig experimental model and was shown to reduce suturing time 2.4-fold [14]; however, porcine ileum is different from human ileum and animal experiment results may not be directly transferred to the human setting, especially when suturing the entire ileal wall encompassing the mucosa, as performed by EndoSew®. We therefore prospectively evaluated the feasibility and safety of EndoSew® in placing a watertight running suture, applying an open technique, in a series of 10 consecutive patients undergoing ileal conduit.

Patients and Methods

Ten consecutive patients undergoing open surgery for an ileal conduit were included in this prospective single-centre pilot study. Exclusion criteria were age < 18 years, chronic inflammatory bowel disease, and having undergone abdominal radiotherapy. The study was approved by the local ethics committee. All patients gave written informed consent.

The EndoSew® device was developed by Karl Storz GmbH & Co. KG (Tuttlingen, Germany) to perform minimally invasive intracorporeal running sutures and has previously been described by Brehmer et al. [14]. So far, only prototypes exist and clinical testing is limited to European countries. The device consists of three key components, the motor, gear and needle unit (Fig. 1). The tip of the needle unit consists of a top and middle downholder, looper, stitch plate and needle (Fig. 2). The sewing process has previously been described by Brehmer et al. [14] and is shown and explained in Fig. 2. The resulting suture is a single-thread running suture type 501 with overedge chain stitches (Fig. 3). Various resorbable threads between 4/0 and 5/0 can been used.

Figure 1.

EndoSew® prototype sewing device.

Figure 2.

Tip of the EndoSew® needle unit: one tissue border is placed between the top and middle downholders, the other tissue border between the middle downholder and the stitch plate. The top and middle downholders pinch both tissue borders while the needle perforates and transports the thread through both tissues. The looper captures the thread, creates a loop and directs it to the next position for needle perforation. When the needle moves to the up position, the two downholders release the tissue borders, allowing the tissues to be manually advanced [12].

Figure 3.

EndoSew® single-thread running suture type 501 with overedge chain stitches. The distance between stitches (a) can range from 1.5 to 4 mm. The stitch depth (b) is 3 mm.

Surgical Technique

Both surgeons performing the current pilot series had previously been trained to use the EndoSew® prototype sewing device on extracorporeal sewing of bovine intestinum and intracorporeal laparoscopic sewing procedures on porcine intestinum.

As routinely performed at our institution, a 15–20-cm long ileal segment was isolated ∼25 cm proximal to the ileocecal valve in an open technique. The proximal end of the isolated ileal segment was closed extracorporeally with a running suture using the EndoSew® device as described below. Both ureters were split and separately anastomosed to the proximal ileal segment by two freehand running sutures according to the Nesbit technique. Finally, the distal ileal segment was anastomosed to the abdominal wall in a nipple-to-stoma fashion.

For the EndoSew® running suture, two 4/0 polyglactin 910 stay sutures were first placed at the proximal end of the ileal segment on both the mesenteric and the antimesenteric sides. The two carefully stretched ileum borders were placed between the top and middle downholders (upper ileum border) and middle downholder and stitch plate (lower ileum border; Fig. 3). The 4/0 polyglactin 910 suture was continuously run in full thickness of the ileal wall from one end to the other, aiming to have a stitch every 3–4 mm (Fig. 4). For the final two stitches, the position of the upper tissue border had to be switched in such a way that both tissue borders were brought together between the middle downholder and stitch plate. Finally, the threads at both ends were manually knotted together with the ends of the stay sutures (Fig. 5).

Figure 4.

Intraoperative sewing with the EndoSew®. The surgeon stretches the ileum using two stay sutures, and moves the bowel from one end to the other while the EndoSew® device is affixed to the operating table.

Figure 5.

Watertight suture line at the proximal end of the ileal conduit completed using only the EndoSew®.

The primary endpoint was to assess the feasibility and safety of the EndoSew® device in placing a watertight, extracorporeal running suture, defined as a complete running suture line on the proximal end of the ileal conduit accomplished by EndoSew® only. After blocking the distal end of the ileal segment with an inflated Foley catheter 20 F, primary watertightness was intra-operatively assessed by filling the ileal segment with 20 mL methylene blue diluted 1:10 with NaCl 0.9% using a syringe. Eventual leaks were closed with additional freehand single polyglactin 910 sutures. On postoperative days 7 and 14, secondary watertightness of the running suture was assessed by loopography, applying 20 mL contrast medium (Telebrix® Gastro, Guerbet, Roissy, France) diluted 1:2 with NaCl 0.9%. Since all 10 running sutures were watertight on day 7 as well as in the first five patients on day 14, loopography on day 14 was omitted in the last five patients after weighing the very low probability of detecting a potential leak against the burden of additional x-ray exposure.

Secondary endpoints were the time requirements ‘equipment preparation time’ (time from beginning to end of assembling the device), ‘equipment in use time’ (time during which the surgeon held the device), and the ‘pure suture time’ (time from first to last stitch). In addition, complications occurring ≤30 days after surgery were assessed according to the Clavien–Dindo classification [15].

A descriptive analysis of the results was performed.

Results

Eight male and two female patients, whose median (range) age was 72 (69–88) years, were included in the study. A complete running suture with EndoSew® was successfully performed in nine patients. In one patient, sewing with EndoSew® had to be abandoned after 50% of the suturing distance because of a mechanical failure of the device. The remaining suturing distance was finished using a freehand running suture. In three patients, two additional single freehand stitches each were placed at the beginning and/or the end of the suture line in order to anchor the thread and to seal tiny leaks. Thus, 6/10 suture lines were watertight after EndoSew® sewing only and all 10 were watertight once additional freehand (anchor) stitches had been placed. Likewise, all running sutures assessed by loopography on postoperative day 7 (10 of 10) and day 14 (5 of 5) were watertight (Table 1).

Table 1. Suture-related technical data, suture tightness and complications.
PatientResults
Suture tightness intra-operativelyTechnical problems EndoSew®Additional freehand single stitchesSuture watertightness at day 7Suture watertightness at day 14Number of stitches, nSuture length, mmEquipment preparation time, minEquipment in use time, minPure suture time, minComplications overall*Complications related to EndoSew® suture*
  1. *According to the five-grade Clavien-Dindo classification system. Risk of additional x-ray exposure outweighed probability of detecting potential leak.
 1NoTransportation failure2YesYes154530255NoneNone
 2YesNoneNoneYesYes175530205Acute on chronic renal insufficiency (grade 4a)None
 3NoTransportation failure2YesYes145010306NoneNone
 4YesNoneNoneYesYes164515144Subileus (grade 1)None
 5YesNoneNoneYesYes14559204NoneNone
 6YesNoneNoneYesOmitted14455153NoneNone
 7YesNoneNoneYesOmitted144515256NoneNone
 8NoTransportation failure2YesOmitted12459186Obstructive pyelonephritis (grade 3a)None
 9YesNoneNoneYesOmitted82515206NoneNone
10NoMechanical failure after 50% of the suture length.Freehand running sutureYesOmitted420101210NoneNone
Median     144512.5205.5  
Range     4–1720–555–3012–303–10  

The median (range) equipment preparation, equipment in use, and pure suture times were 12.5 (5–30), 20 (12–30) and 5.5 (3–10) min, respectively. The median (range) number of stitches was 14 (4–17), median (range) suture length 4.5 (2.0–5.5) cm (Table 1).

Three patients had postoperative complications: one patient developed an acute-on-chronic renal insufficiency, necessitating temporary dialysis for several days (Clavien–Dindo grade IVa); one patient had a transient subileus, which resolved spontaneously (grade I); and one patient with pre-existing ureteropelvic junction obstruction developed an obstructive pyelonephritis, requiring nephrostomy placement (grade IIIa). No suture-related complications were encountered (Table 1).

Discussion

The first experience with laparoscopic radical cystectomy and complete intracorporeal construction of a continent orthotopic ileal neobladder was reported 10 years ago [3]. Since then, robot-assisted radical cystectomy has evolved rapidly and supports laparoscopic surgeons in the performance of skill-demanding manipulations. As a consequence, urological centres worldwide are increasingly offering minimally invasive cystectomies to their patients. The reconstructive part of the procedure is still widely performed through a mini-laparotomy to improve the exposure, bowel preparation and resection, and to aid the time-consuming sewing, especially when performing running sutures for, e.g. orthotopic ileal diversions [7]. In the present study, we report on the first consecutive series of ileal conduits performed in humans using the novel prototype sewing device EndoSew®.

In 9/10 patients the entire running sutures were successfully performed in full length with EndoSew®, but minor device-related thread transportation irregularities precluded prompt perfect suture lines in all patients and prolonged the time requirements. Nevertheless, in 6/10 patients the suture lines were immediately watertight after mechanical sewing with EndoSew®. In one of the four remaining patients 50% of the suture line had to be completed by a freehand running suture because of a mechanical blockage of the device, while in three patients only two additional freehand stitches each were necessary at the beginning and/or at the end of the suture lines to anchor the thread and seal tiny leaks. The beginning and the end of the suture process represent the critical procedural steps as precise placement of both ileal borders between the two downholders and the stitch plate is crucial for a tight and accurate running suture. Potential small leaks at these sites can be closed peri-operatively with solitary additional freehand stitches if necessary. The fact that no suture leaks were detected in between stitches at any time shows that the EndoSew® running suture provides watertight sealing once the first stitch is correctly anchored. This belies our initial hypothesis that a suture of the entire ileal wall encompassing the mucosa as performed by EndoSew® may not be safe. Hence, this technology has substantial potential to simplify the intracorporeal construction of urinary diversions.

In the present series, equipment preparation and equipment in use times, especially during the critical steps at the beginning and the end of the running suture, were considerable in the first two patients. With growing experience, however, these time requirements decreased. Three patients experienced postoperative complications, none of which were suture related. From these results, albeit in a limited series of 10 patients, the application of EndoSew® appears to be safe.

Although robot assistance is thought to facilitate intracorporeal laparoscopic sewing [16], this remains the most demanding skill in minimally invasive surgery [17]. For this reason, several devices for extracorporeal [18] and intracorporeal stitching and knotting have been developed [19-21] that greatly facilitate the placing of interrupted sutures. For urinary diversions, however, running sutures are essential. Sewing machines have the potential to substantially simplify these skill-intensive and time-consuming manipulations. The EndoSew® prototype presented here was first tested in a porcine model several years ago by Brehmer et al. [14]. They found it both simple to master and reliable, its greatest advantage being a 2.4-fold time-saving compared with straight laparoscopic suturing. Since then, Martinschek et al. [22] have been the only ones to report EndoSew® application in humans. In their single case report they performed an open EndoSew® suture to close parts (16 cm) of an ileal neobladder. Their time for suturing the 16-cm ileum was 25 min, which is in line with our experience.

New techniques other than traditional sewing, e.g. laparoscopic stapling, are in widespread use for the construction of urinary diversions [9, 10]. Urinary stones and chronic UTIs, however, are well known complications of non-absorbable staples [11-13]; therefore, currently available, non-absorbable staple lines are not suitable for the construction of urinary diversions. EndoSew® offers a key advantage in this regard by delivering a suture made of resorbable thread, which for decades has been used for the construction of urinary diversions. Moreover, these threads are widely available and cheap.

A potential limitation of the present study is that we tested the EndoSew® device in the context of an extracorporeal surgical approach, although it is intended to reduce intracorporeal laparoscopic sewing time [14]; however, our goal was to test the intraoperative feasibility of the EndoSew® sewing device in the human setting and to assess patient safety, irrespective of the surgical approach. A point of criticism may also be the intra-operative assessment of watertightness using a syringe. This might have overestimated the ‘physiological leakage’ by artificially produced pressures higher than a 30–40-cm water column. Since patient's safety was our major concern, we conducted an extra freehand stitch rather than risk postoperative complications resulting from a leakage. Another limitation is that the EndoSew® device is not yet commercially available, but technical refinement of EndoSew® is ongoing and it is projected for release as soon as it is completed.

In conclusion, the novel prototype sewing device EndoSew® was both feasible and safe in placing a resorbable running suture for ileal conduits. It has the potential to facilitate the intracorporeal suturing required in reconstructive urology for construction of urinary diversions. Further technical refinements are planned before its commercial release.

Conflict of Interest

None declared.

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