- Email: [email protected]
Feasibility of Transrectal Hybrid Natural Orifice Transluminal Endoscopic Surgery (NOTES) Nephrectomy in the Cadaveric Model
Laparoscopy and Robotics Feasibility of Transrectal Hybrid Natural Orifice Transluminal Endoscopic Surgery (NOTES) Nephrectomy in the Cadaveric Model Wassim M. Bazzi, Sean P. Stroup, Seth A. Cohen, Takayuki Dotai, Ryan P. Kopp, Caroline Colangelo, Omer A. Raheem, Sonia Ramamoorthy, Mark Talamini, Santiago Horgan, Christopher J. Kane, and Ithaar H. Derweesh OBJECTIVE
METHODS
RESULTS
CONCLUSION
To examine feasibility of transrectal hybrid natural orifice transluminal endoscopic surgery (NOTES) nephrectomy in human cadavers in the evolution of this technique, as transrectal hybrid NOTES nephrectomy has been demonstrated in the porcine model. Four hybrid transrectal NOTES nephrectomies were performed on 4 cadavers (3 female/1 male, 2 right/2 left). Pneumoperitoneum was created by periumbilical 12-mm trocar, through which a laparoscope was advanced to obtain intra-abdominal visualization. A 4-cm horizontal incision was made 2-cm above the dentate line and a submucosal tunnel was created in the posterior rectal wall/presacral space. A dual-channel gastroscope was advanced through the submucosal tunnel and retroperitoneum to the level of the kidney using air insufflation. A peritoneal window was created and renal mobilization was completed. A transumbilically applied laparoscopic 45-mm stapler was used to transect the ureter and renal hilum. A specimen entrapment bag was deployed transrectally for specimen extraction, followed by transrectal incision closure. Transrectal NOTES nephrectomy was successfully performed in all cases, with intact specimen extraction. Median weight was 77 kg (range 74-85 kg); median body mass index (BMI) was 30.1 kg/m2 (range 25.6-31.2 kg/m2). Mean operative time was 175 minutes (range 150-210 minutes). Median transrectal access time was 36 minutes (range 24-47 minutes). Median dimensions of removed kidneys were length 11.2 cm (range 10-12 cm), width 5 cm (range 4.5-6 cm), and thickness 3.8 cm (range 3-4.5 cm). Transrectal hybrid NOTES nephrectomy in the cadaver model is feasible with intact specimen extraction and acceptable operative times. Preclinical survival studies are requisite to assess sterility and complications. This approach may be an alternative to transvaginal access. UROLOGY 80: 590 –595, 2012. © 2012 Elsevier Inc. All rights reserved.
atural orifice transluminal endoscopic surgery (NOTES) is an emerging platform for minimally invasive surgery in urology. NOTES involves intentional puncture of one of the viscera to access the abdominal cavity and perform an intra-abdominal operation.1,2 NOTES offers advantages of minimally invasive surgery and also eliminates trauma to the abdominal wall and its potential sequelae.1-8 Indeed, applications of NOTES in urologic surgery are an expanding field of inves-
N
tigation. Recent reports demonstrate feasibility and safety of NOTES transvaginal nephrectomy. Although other approaches for performing NOTES have been described, such as transgastric or transcystic, these approaches are generally not large enough for intact extraction of larger solid organs, such as a kidney. We recently reported on the transrectal route as an alternative for nephrectomy in the porcine model,9 and herein, we investigate the feasibility and reproducibility of transrectal hybrid NOTES nephrectomy in the human cadaveric model.
Financial Disclosure: Santiago Horgan is a consultant to Intuitive, Inc, Ethicon Endosurgery, Inc; Christopher J. Kane is a consultant to Intuitive, Inc; and Ithaar H. Derweesh is a consultant to Ethicon Endosurgery, Inc. Funding Support: Stephen Weissman Kidney Cancer Research Fund. From the Department of Surgery/Division of Urology, Department of Surgery/ Division of Minimally Invasive Surgery, and the Center for the Future of Surgery, University of California, San Diego School of Medicine, La Jolla, CA Reprint requests: Ithaar H. Derweesh, M.D., Moores UCSD Cancer Center, University of California, San Diego School of Medicine, 3855 Health Sciences Dr, #0987, La Jolla, CA 92093-0987. E-mail: [email protected] Submitted: March 7, 2012, accepted (with revisions): June 13, 2012
MATERIAL AND METHODS
590
© 2012 Elsevier Inc. All Rights Reserved
Procedural steps, approach, and equipment used are summarized in Table 1. Four cadavers (3 female/1 male) were placed in the lithotomy position and secured to the table. Fleets enema was delivered to clear rectal vault from stool. A Veress needle (Ethicon Endo-surgery, Cincinnati, OH) was used for abdominal insufflation to 15 mm Hg intra-abdominal pressure. A 12 mm Xcel trocar (Ethicon Endo-surgery) was inserted at the 0090-4295/12/$36.00 http://dx.doi.org/10.1016/j.urology.2012.06.026
Table 1. Step-by-step approach of transrectal hybrid nephrectomy in cadaver model Procedural Step (and Approach) Step 1: transumbilical access Step 2: transrectal access/creation of submucosal tunnel and dissection into presacral space (transrectal approach) Step 3: dissection up retroperitoneal space to level of kidney (transrectal approach) Step 4: creation of peritoneal window (transrectal approach) Step 5: renal mobilization and dissection (transrectal primarily, with transumbilical assistance)
Step 6: hilar and ureteral ligation (transumbilical) Step 7: specimen entrapment (transrectal) Step 8: incision closure (transrectal)
Description of Step and Equipment Used Cadaver in dorsal lithotomy position. Place 12-mm trocar at umbilicus. Cadaver in dorsal lithotomy position. Horizontal incision performed 2 cm above dentate line in posterior rectal wall mucosa. Create submucosal tunnel and dissect into presacral space, along avascular areolar plane anterior to Waldeyer’s fascia). Place gastroscope. Cadaver in flank position. Air insufflation and dissection with gastroscope through presacral space and out of pelvis; monitoring by laparoscope. Visualization by gastroscope and transumbilically inserted camera. Snare probe passed through gastroscope. Gastroscope used for visualization exclusively. Snare (passed through the gastroscope) used to take down white line of Toldt, posterior attaching fibers, and for medial visceral rotation. Transumbilically passed bowel grasper and Kittner used to provide traction on bowel to facilitate dissection. Transumbilically passed harmonic scalpel and Kittner for anterior upper pole dissection and hilar skeletalization. Transumbilically passed laparoscopic stapler; ligation of ureter and renal hilum en bloc. Gastroscope exchanged for specimen entrapment bag. Monitoring with laparoscope. Specimen extracted through transrectal incision. Dorsal lithotomy. External rectotomy closure.
Figure 1. (A) Transrectal access: following rectotomy 2 cm above the dentate line in the posterior rectal wall, a submucosal tunnel is created and elevated with sharp dissection. (B) Transrectal access: insertion of a gastroscope through the submucosal tunnel and into presacral space. (C) Transrectal access: dissection through avascular plane in presacral space. (D) Transrectal access: creation of the peritoneal window. (E) Renal mobilization: gastroscope with snare taking down the white line of Toldt (viewed by laparoscope). (F) En bloc transection of renal hilum: by vascular loaded stapler (gastroscope view). (Color version available online.) umbilicus under direct visualization with a 10 mm zero degree rigid camera (Stryker, Kalamazoo, MI). Rectotomy consisted of a 3-cm long horizontal incision in the rectal mucosa, performed 2 cm above the dentate line in the posterior rectal wall (Fig. 1A). A nasal speculum or Army-Navy retractors may be placed to facilitate dissection. A submucosal UROLOGY 80 (3), 2012
tunnel was created and elevated with sharp dissection, and then dissection was carried into the presacral space, cranially along the avascular areolar plane anterior to Waldeyer’s fascia, to extend the tunnel. A dual channel gastroscope was subsequently introduced (Olympus GIF 2T-160, Center Valley, PA; Fig. 1B). The cadaver was repositioned in the flank position 591
Figure 2. (A) Transrectal deployment of specimen extraction bag through the peritoneotomy (laparoscope view). (B) Kidney in specimen entrapment bag being pulled through the peritoneotomy (laparoscope view). (C) Rectal extraction of specimen. (D) Rectotomy closure. (E) Final specimen. (Color version available online.)
with the target side up to allow for performance of right or left-sided nephrectomy, and using air-insufflation (Fig. 1C) and gentle advancement, the gastroscope was veered laterally toward the intended target (right or left). Transabdominal laparoscopic monitoring of the progress of the gastroscope was used to assess progress and to also provide direction for the endoscope through the retroperitoneum. For a right-sided procedure, the gastroscope is deflected upward and to the right and advanced out of the presacral space, ultimately demonstrating the peritoneum medially and the iliac vessels laterally. For a leftsided procedure, the gastroscope is deflected upward and toward the left, ultimately demonstrating the peritoneum medically and the iliac vessels laterally. Visualization of the ureter guides further cephalad dissection toward the kidney, and the peritoneotomy is made using a snare probe (Olympus) inserted through the gastroscope channel (Fig. 1D). The peritoneotomy is then extended with the snare, around the tail of Gerota’s and to the white line of Toldt (Fig. 1E), during which medial traction, if necessary, is provided by a Kittner dissector (Ethicon) inserted through the transumbilical trocar. Medial visceral rotation of the ascending colon (right-sided) and descending colon (left-sided) is then carried out by placement of medical traction by a transumbilically applied bowel grasper to facilitate takedown of attaching fibers by the endoscopic snare probe. Posterior mobilization of the kidney is carried out by the snare probe through the gastroscope with traction by a transumbilical bowel grasper. Further mobilization of the upper pole and renal hilar dissection are undertaken by a transumbilically inserted Harmonic scalpel (Ethicon)—in addition to the gastroscope-deployed snare and flexible graspers. Using visualization from the gastroscope, an EndoPath laparoscopic 45-mm stapler (Ethicon) was used to transect the ureter followed by the renal hilum in an en bloc fashion (Fig. 1F). 592
After completion of renal mobilization, the peritoneal window at the gastroscope insertion site was enlarged. The gastroscope was then exchanged for an EndoCatch bag (Covidien, Mansfield, MA), which was deployed through the rectotomy following the course established by the gastroscope dissection. The EndoCatch bag positioning was guided by visualization through the periumbilical port, and the entrapped kidney was removed intact from the rectum (Fig. 2A to C). The nasal speculum was placed in the anus, and the rectotomy was closed from the outside primarily with interrupted 2-0 Vicryl (polyglactin, Ethicon, Somerville, NJ; Fig. 2D).
Data Collection Operative time (from pneumoperitoneum to closure, minutes) and transrectal access time (minutes) was recorded. The harvested specimen was measured (Fig. 2E), in addition to cadaver weight, transrectal access and operative time, and dimensions of the removed kidney. Cadaver weight and height were used to calculate body mass index (BMI, kg/m2).
RESULTS All cases of transrectal hybrid NOTES nephrectomy (2right/2-left) were successfully completed without conversion to multiport laparoscopy or open surgery. Transrectal access through the submucosal tunnel was able to reach the targeted side in all cadavers with guidance by the transumbilical laparoscope monitoring. Right-sided access into the retroperitoneum was more straightforward, with a wider gap for dissection between the peritoneum and the iliac vessels and ureter than the left. Consequently, transabdominal visual guidance was reUROLOGY 80 (3), 2012
ferred to less on the right side. Entry into the peritoneum facilitated better landmark identification and facilitated renal mobilization and hilar ligation. In all cases, transrectal deployment of the specimen entrapment bag was successful, leading to intact specimen extraction. There were no difficulties with specimen extraction in any of our cases. Median cadaver weight was 77 kg (range 70-85 kg); median BMI (kg/m2) was 30.1 (range 25.6-31.2). Median total operative time was 175 minutes (range 150-210 minutes), with a median transrectal access time of 36 minutes (range 24-47 minutes), and ⬎75% of the procedure being performed through the transrectal access. Median kidney length, width, and thickness (range, cm) were 11.3 (10-12), 5 (4.5-6), and 3.8 (3-4.5), respectively.
COMMENT Since introduction of the concept of natural orifice surgery by Gettman et al10 in 2002 and by Kalloo et al3 in 2004, an expanding range of general surgical and urologic surgical procedures have been performed using a variety of different entry points in a porcine model.9-19 In humans, Breda et al20 were able to deliver a nonfunctioning kidney through the vagina and Gill et al21 reported 10 clinical vaginal extractions of kidney after multiport laparoscopic nephrectomy. Sotelo et al7 and Kaouk et al22 reported hybrid and pure transvaginal NOTES radical nephrectomy in humans, respectively. Our transrectal approach allows a larger colonic access point with easier closure afterward without the need to deploy endoscopic clips.9,23 This has the advantage of access to retroperitoneal and intraperitoneal organs with extraction of larger specimens/organs using larger trocars and deployed rigid and semirigid instruments. The approach is applicable to men and women, avoiding violation of sexual and reproductive organs. Given that the dissection through the pelvis was posterior to the rectum, we avoided contact with the posterior aspects of the prostate and seminal vesicle. Furthermore, the peritoneotomy is made cephalad to intraperitoneal structures, such as the fallopian tubes, which are displaced anteriorly in the overlying peritoneum during the initial dissection by the gastroscope. The key maneuver in the transrectal access is entry into the avascular plane anterior to Waldeyer’s fascia to facilitate cephalad dissection along the presacral space— deviation from this plane posteriorly would result in bleeding and potential injury to sacral vessels and hypogastric nerves, and anteriorly, would create mesorectal bleeding. The major drawback for the transrectal approach is potential for bacterial contamination of the abdomen. There are reports of a small series of animal survival models using different access and sterilization techniques with promising preliminary results revealing good healing of colonic incision sites. Fong et al24 performed transcolonic NOTES abdominal exploration on 6 pigs—all survived for the study duration of 2 weeks, at which time necropsy was performed for inflammatory UROLOGY 80 (3), 2012
infiltrates, abscesses, mucosal ulcerations, and serositis at colonic closure sites; however, there was no evidence for microscopic peritonitis in any of the pigs. Similar findings were reported by Wilhelm et al25 who performed transcolonic NOTES abdominal exploration in 5 pigs survived to necropsy at 10 days with no signs of peritonitis, infection, or significant adhesions. In our experimental transrectal preclinical and cadaveric NOTES studies, we have recapitulated the hybrid approach used by our institutional review board-approved clinical trials of NOTES (NCT00531219, NCT00530998)26,27 using the transumbilical trocar to guide our transrectal access, assist in renal mobilization, and for deployment of the stapler. Indeed, more than 75% of the procedure is performed via instrumentation inserted via the natural orifice, therefore, fulfilling criteria for hybrid NOTES, as proposed by Box et al.28 Of the 8 steps outlined in Table 1, 5 are purely transrectal (Step 2-access, Step 3-dissection up to retroperitoneum, Step 4-creation of peritoneal window, Step 7-specimen entrapment and extraction, and Step 8-rectotomy closure); two steps are transabdominal (access, ureteral and hilar ligation); and 1 step is mixed (Step 5-renal mobilization-mostly transrectal, from take down of the white line, medial visceral rotation, posterior dissection were transrectal, with the upper pole anterior dissection being mostly transabdominal and hilar skeletalization being mixed). From the median operative time of 175 minutes, the 2 purely transabdominal steps (obtaining laparoscopic access and ureteral and renal hilar ligation) took no more than 15 minutes in all cases performed. Indeed, as technology continues to evolve, a purely transrectal NOTES approach using a mixed transperitoneal-retroperitoneal (as demonstrated in our study), or exclusively retroperitoneal dissection may be possible. When compared to our reported porcine experiments,9 a human cadaveric approach posed more challenges and instrument limitations; longer torso, thicker perinephric fat and Gerota’s fascia, complex renal hilar anatomy, and inability to achieve optimal abdominal cavity pneumoperitoneum due to abdominal wall rigidity. Right-sided transrectal access was also more straightforward. The presence of the sigmoid colon on the left side, overlying the pelvic inlet, decreases room to maneuver between the peritoneum and the iliac vessels compared to the right side, and we noted that we referred to the transumbilical laparoscope more to assist in positioning guidance. As a matter of general principle, we considered maintaining the peritoneum medially as a critical landmark as we exited the pelvis and transited the iliac vessels with the gastroscope. The next important landmark was identification of the ureter, coursing laterally over the iliac vessels, which we traced toward the kidney. The dissection and mobilization of the kidney, especially of the upper pole, which is in a more posterior plane than the lower pole, was more challenging. However, this issue was addressed by using the Kittner and harmonic scalpel 593
to take down the upper pole attachments anteriorly, and by using the bowel grasper or Kittner dissector to place medial traction while using the articulation of the endoscope with deployed snare to take down posterior attachments. The hybrid approach allowed effective intra-abdominal triangulation combinations (snare and grasper through the gastroscope and Kittner transumbilically, or harmonic scalpel transabdominally with a transrectal snare through the gastroscope, for instance). Significant challenges locating identifiable landmarks and directional guides were faced and were addressed by transabdominal laparoscope monitoring. There were no difficulties with specimen extraction, given the easy transit of the entrapped specimen through the peritoneotomy into the pelvis and the presacral space. The distensibility of the avascular, areolar plane in the presacral space in the human pelvis facilitates the extraction. In this study with the cadaveric model, our median operative time of 175 minutes and transrectal access time of 36 minutes is similar to the total operative and transrectal access times of 180 and 30 minutes, respectively, which we had previously reported for NOTES hybrid transrectal nephrectomy in the porcine model.9 Our reported times compare to those reported by other groups for NOTES nephrectomy—with a mean operative time of 170 minutes in transvaginal cadaveric models29 and 420 minutes in human transvaginal nephrectomy.22 Although it does replicate anatomy with its posed challenges, the cadaveric model has its drawbacks— especially for the abdominal wall rigidity, hence, the inability to achieve ideal pneumoperitoneum. Additionally, the nondiscriminatory appearance of cadaveric tissue challenged organ and structure identification, which was helped by laparoscopic monitoring with the hybrid approach. Furthermore, despite the median BMI being in the obese range, with potential implications regarding abdominal and retroperitoneal fat, and given the limitations of the cadaveric model with respect to tissue/landmark identification, we demonstrated that using a hybrid NOTES approach we were able to navigate to the kidney and then remove it intact. As proof of principle for the challenges of human anatomy, demonstration of the feasibility of our approach is critical before proceeding with further study.
CONCLUSIONS Transrectal hybrid NOTES nephrectomy in the cadaveric model is feasible and reproducible with intact specimen extraction and acceptable operative times. Preclinical survival studies are requisite to assess sterility and complications of this procedure before we bridge this new surgical concept to human clinical trials. References 1. Pearl JP, Ponsky JL. Natural orifice translumenal endoscopic surgery: a critical review. J Gastrointest Surg. 2008;12:1293-1300.
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2. Wagner OJ, Hagen M, Morel P, et al. Who should do NOTES? Initial endoscopic performance of laparoscopic surgeons compared to gastroenterologists and untrained individuals. J Gastrointest Surg. 2008;12:1724-1729. 3. Kalloo AN, Singh VK, Jagannath SB, et al. Flexible transgastric peritoneoscopy: a novel approach to diagnostic and therapeutic interventions in the peritoneal cavity. Gastrointest Endosc. 2004; 60:114-117. 4. Pai RD, Fong DG, Bundga ME, et al. Transcolonic endoscopic cholecystectomy: a NOTES survival study in a porcine model (with video). Gastrointest Endosc. 2006;64:428-434. 5. Kantsevoy SV, Hu B, Jagannath SB, et al. Transgastric endoscopic splenectomy: is it possible? Surg Endosc. 2006;20:522-525. 6. Bergström M, Ikeda K, Swain P, et al. Transgastric anastomosis by using flexible endoscopy in a porcine model (with video). Gastrointest Endosc. 2006;63:307-312. 7. Sotelo R, de Andrade R, Fernández G, et al. NOTES hybrid transvaginal radical nephrectomy for tumor: stepwise progression toward a first successful clinical case. Eur Urol. 2010;57:138-144. 8. Chow A, Purkayastha S, Dosanjh D, et al. Patient reported outcomes and their importance in the development of novel surgical techniques. Surg Innov. 2011 [Epub ahead of print]. 9. Bazzi WM, Wagner O, Stroup SP, et al. Transrectal hybrid natural orifice transluminal endoscopic surgery (NOTES) nephrectomy in a porcine model. Urology. 2011;77:518-523. 10. Gettman MT, Lotan Y, Napper CA, et al. Transvaginal laparoscopic nephrectomy: development and feasibility in the porcine model. Urology. 2002;59:446-450. 11. Swain P. Nephrectomy and natural orifice translumenal endoscopy (NOTES): transvaginal, transgastric, transrectal, and transvesical approaches. J Endourol. 2008;22:811-818. 12. Granberg CF, Frank I, Gettman MT. Transvesical NOTES: current experience and potential implications for urologic applications. J Endourol. 2009;23:747-752. 13. Lima E, Branco F, Parente J, et al. Transvesical natural orifice transluminal endoscopic surgery (NOTES) nephrectomy with kidney morcellation: a proof of concept study. BJU Int. 2012;109: 1533-1537. 14. Baldwin DD, Tenggardjaja C, Bowman R, et al. Hybrid transureteral natural orifice translumenal endoscopic nephrectomy: a feasibility study in the porcine model. J Endourol. 2011;25: 245-250. 15. Nagele U, Anastasiadis AG, Walcher U, et al. Natural orifice (NOTES) transurethral sutureless radical prostatectomy with thulium laser support: first patient report. World J Urol. 2011 [Epub ahead of print]. 16. Clayman RV, Box GN, Abraham JB, et al. Rapid communication: transvaginal single-port NOTES nephrectomy: initial laboratory experience. J Endourol. 2007;21:640-644. 17. Isariyawongse JP, McGee MF, Rosen MJ, et al. Pure natural orifice transluminal endoscopic surgery (NOTES) nephrectomy using standard laparoscopic instruments in the porcine model. J Endourol. 2008;22:1087-1091. 18. Boylu U, Oommen M, Joshi V, et al. Natural orifice translumenal endoscopic surgery (NOTES) partial nephrectomy in a porcine model. Surg Endosc. 2010;24:485-489. 19. Haber GP, Brethauer S, Crouzet S, et al. Pure ‘natural orifice transluminal endoscopic surgery’ for transvaginal nephrectomy in the porcine model. BJU Int. 2009;104:1260-1264. 20. Breda G, Silvestre P, Giunta A, et al. Laparoscopic nephrectomy with vaginal delivery of the intact kidney. Eur Urol. 1993;24:116117. 21. Gill IS, Cherullo EE, Meraney AM, et al. Vaginal extraction of the intact specimen following laparoscopic radical nephrectomy. J Urol. 2002;167:238-241. 22. Kaouk JH, Haber GP, Goel RK, et al. Pure natural orifice translumenal endoscopic surgery (NOTES) transvaginal nephrectomy. Eur Urol. 2010;57:723-726.
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23. Ramamoorthy SL, Fischer LJ, Jacobsen G, et al. Transrectal endoscopic retrorectal access (TERA): a novel NOTES approach to the peritoneal cavity. J Laparoendosc Adv Surg Tech A. 2009;19:603606. 24. Fong DG, Pai RD, Thompson CC. Transcolonic endoscopic abdominal exploration: a NOTES survival study in a porcine model. Gastrointest Endosc. 2007;65:312-318. 25. Wilhelm D, Meining A, von Delius S, et al. An innovative, safe and sterile sigmoid access (ISSA) for NOTES. Endoscopy. 2007;39: 401-406. 26. Horgan S, Talamini MA, University of California, San Diego. Minimally invasive surgery: using natural orifice translumenal endoscopic surgery (NOTES). Clinicaltrials.gov (internet). Bethesda, Maryland: National Library of Medicine. 2000 – (cited 2012). Available at: http://clinicaltrials.gov/ct2/results?
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term⫽NCT00531219 NLM Identifier: NCT00531219. Accessed March 3, 2012. 27. Horgan S, Talamini MA, University of California, San Diego. Minimally invasive surgery: using natural orifices (NOTES). Clinicaltrials.gov [Internet]. Bethesda, Maryland: National Library of Medicine. 2000 – (cited 2012). Available from: http://clinicaltrials. gov/ct2/results?term⫽⫹NCT00530998 NLM Identifier: NCT00530998. Accessed March 3, 2012. 28. Box G, Averch T, Cadeddu J, et al. Nomenclature of natural orifice translumenal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS) procedures in urology. J Endourol. 2008; 22:2575-2581. 29. Aron M, Berger AK, Stein RJ, et al. Transvaginal nephrectomy with a multichannel laparoscopic port: a cadaver study. BJU Int. 2009;103:1537-1541.
595
METHODS
RESULTS
CONCLUSION
To examine feasibility of transrectal hybrid natural orifice transluminal endoscopic surgery (NOTES) nephrectomy in human cadavers in the evolution of this technique, as transrectal hybrid NOTES nephrectomy has been demonstrated in the porcine model. Four hybrid transrectal NOTES nephrectomies were performed on 4 cadavers (3 female/1 male, 2 right/2 left). Pneumoperitoneum was created by periumbilical 12-mm trocar, through which a laparoscope was advanced to obtain intra-abdominal visualization. A 4-cm horizontal incision was made 2-cm above the dentate line and a submucosal tunnel was created in the posterior rectal wall/presacral space. A dual-channel gastroscope was advanced through the submucosal tunnel and retroperitoneum to the level of the kidney using air insufflation. A peritoneal window was created and renal mobilization was completed. A transumbilically applied laparoscopic 45-mm stapler was used to transect the ureter and renal hilum. A specimen entrapment bag was deployed transrectally for specimen extraction, followed by transrectal incision closure. Transrectal NOTES nephrectomy was successfully performed in all cases, with intact specimen extraction. Median weight was 77 kg (range 74-85 kg); median body mass index (BMI) was 30.1 kg/m2 (range 25.6-31.2 kg/m2). Mean operative time was 175 minutes (range 150-210 minutes). Median transrectal access time was 36 minutes (range 24-47 minutes). Median dimensions of removed kidneys were length 11.2 cm (range 10-12 cm), width 5 cm (range 4.5-6 cm), and thickness 3.8 cm (range 3-4.5 cm). Transrectal hybrid NOTES nephrectomy in the cadaver model is feasible with intact specimen extraction and acceptable operative times. Preclinical survival studies are requisite to assess sterility and complications. This approach may be an alternative to transvaginal access. UROLOGY 80: 590 –595, 2012. © 2012 Elsevier Inc. All rights reserved.
atural orifice transluminal endoscopic surgery (NOTES) is an emerging platform for minimally invasive surgery in urology. NOTES involves intentional puncture of one of the viscera to access the abdominal cavity and perform an intra-abdominal operation.1,2 NOTES offers advantages of minimally invasive surgery and also eliminates trauma to the abdominal wall and its potential sequelae.1-8 Indeed, applications of NOTES in urologic surgery are an expanding field of inves-
N
tigation. Recent reports demonstrate feasibility and safety of NOTES transvaginal nephrectomy. Although other approaches for performing NOTES have been described, such as transgastric or transcystic, these approaches are generally not large enough for intact extraction of larger solid organs, such as a kidney. We recently reported on the transrectal route as an alternative for nephrectomy in the porcine model,9 and herein, we investigate the feasibility and reproducibility of transrectal hybrid NOTES nephrectomy in the human cadaveric model.
Financial Disclosure: Santiago Horgan is a consultant to Intuitive, Inc, Ethicon Endosurgery, Inc; Christopher J. Kane is a consultant to Intuitive, Inc; and Ithaar H. Derweesh is a consultant to Ethicon Endosurgery, Inc. Funding Support: Stephen Weissman Kidney Cancer Research Fund. From the Department of Surgery/Division of Urology, Department of Surgery/ Division of Minimally Invasive Surgery, and the Center for the Future of Surgery, University of California, San Diego School of Medicine, La Jolla, CA Reprint requests: Ithaar H. Derweesh, M.D., Moores UCSD Cancer Center, University of California, San Diego School of Medicine, 3855 Health Sciences Dr, #0987, La Jolla, CA 92093-0987. E-mail: [email protected] Submitted: March 7, 2012, accepted (with revisions): June 13, 2012
MATERIAL AND METHODS
590
© 2012 Elsevier Inc. All Rights Reserved
Procedural steps, approach, and equipment used are summarized in Table 1. Four cadavers (3 female/1 male) were placed in the lithotomy position and secured to the table. Fleets enema was delivered to clear rectal vault from stool. A Veress needle (Ethicon Endo-surgery, Cincinnati, OH) was used for abdominal insufflation to 15 mm Hg intra-abdominal pressure. A 12 mm Xcel trocar (Ethicon Endo-surgery) was inserted at the 0090-4295/12/$36.00 http://dx.doi.org/10.1016/j.urology.2012.06.026
Table 1. Step-by-step approach of transrectal hybrid nephrectomy in cadaver model Procedural Step (and Approach) Step 1: transumbilical access Step 2: transrectal access/creation of submucosal tunnel and dissection into presacral space (transrectal approach) Step 3: dissection up retroperitoneal space to level of kidney (transrectal approach) Step 4: creation of peritoneal window (transrectal approach) Step 5: renal mobilization and dissection (transrectal primarily, with transumbilical assistance)
Step 6: hilar and ureteral ligation (transumbilical) Step 7: specimen entrapment (transrectal) Step 8: incision closure (transrectal)
Description of Step and Equipment Used Cadaver in dorsal lithotomy position. Place 12-mm trocar at umbilicus. Cadaver in dorsal lithotomy position. Horizontal incision performed 2 cm above dentate line in posterior rectal wall mucosa. Create submucosal tunnel and dissect into presacral space, along avascular areolar plane anterior to Waldeyer’s fascia). Place gastroscope. Cadaver in flank position. Air insufflation and dissection with gastroscope through presacral space and out of pelvis; monitoring by laparoscope. Visualization by gastroscope and transumbilically inserted camera. Snare probe passed through gastroscope. Gastroscope used for visualization exclusively. Snare (passed through the gastroscope) used to take down white line of Toldt, posterior attaching fibers, and for medial visceral rotation. Transumbilically passed bowel grasper and Kittner used to provide traction on bowel to facilitate dissection. Transumbilically passed harmonic scalpel and Kittner for anterior upper pole dissection and hilar skeletalization. Transumbilically passed laparoscopic stapler; ligation of ureter and renal hilum en bloc. Gastroscope exchanged for specimen entrapment bag. Monitoring with laparoscope. Specimen extracted through transrectal incision. Dorsal lithotomy. External rectotomy closure.
Figure 1. (A) Transrectal access: following rectotomy 2 cm above the dentate line in the posterior rectal wall, a submucosal tunnel is created and elevated with sharp dissection. (B) Transrectal access: insertion of a gastroscope through the submucosal tunnel and into presacral space. (C) Transrectal access: dissection through avascular plane in presacral space. (D) Transrectal access: creation of the peritoneal window. (E) Renal mobilization: gastroscope with snare taking down the white line of Toldt (viewed by laparoscope). (F) En bloc transection of renal hilum: by vascular loaded stapler (gastroscope view). (Color version available online.) umbilicus under direct visualization with a 10 mm zero degree rigid camera (Stryker, Kalamazoo, MI). Rectotomy consisted of a 3-cm long horizontal incision in the rectal mucosa, performed 2 cm above the dentate line in the posterior rectal wall (Fig. 1A). A nasal speculum or Army-Navy retractors may be placed to facilitate dissection. A submucosal UROLOGY 80 (3), 2012
tunnel was created and elevated with sharp dissection, and then dissection was carried into the presacral space, cranially along the avascular areolar plane anterior to Waldeyer’s fascia, to extend the tunnel. A dual channel gastroscope was subsequently introduced (Olympus GIF 2T-160, Center Valley, PA; Fig. 1B). The cadaver was repositioned in the flank position 591
Figure 2. (A) Transrectal deployment of specimen extraction bag through the peritoneotomy (laparoscope view). (B) Kidney in specimen entrapment bag being pulled through the peritoneotomy (laparoscope view). (C) Rectal extraction of specimen. (D) Rectotomy closure. (E) Final specimen. (Color version available online.)
with the target side up to allow for performance of right or left-sided nephrectomy, and using air-insufflation (Fig. 1C) and gentle advancement, the gastroscope was veered laterally toward the intended target (right or left). Transabdominal laparoscopic monitoring of the progress of the gastroscope was used to assess progress and to also provide direction for the endoscope through the retroperitoneum. For a right-sided procedure, the gastroscope is deflected upward and to the right and advanced out of the presacral space, ultimately demonstrating the peritoneum medially and the iliac vessels laterally. For a leftsided procedure, the gastroscope is deflected upward and toward the left, ultimately demonstrating the peritoneum medically and the iliac vessels laterally. Visualization of the ureter guides further cephalad dissection toward the kidney, and the peritoneotomy is made using a snare probe (Olympus) inserted through the gastroscope channel (Fig. 1D). The peritoneotomy is then extended with the snare, around the tail of Gerota’s and to the white line of Toldt (Fig. 1E), during which medial traction, if necessary, is provided by a Kittner dissector (Ethicon) inserted through the transumbilical trocar. Medial visceral rotation of the ascending colon (right-sided) and descending colon (left-sided) is then carried out by placement of medical traction by a transumbilically applied bowel grasper to facilitate takedown of attaching fibers by the endoscopic snare probe. Posterior mobilization of the kidney is carried out by the snare probe through the gastroscope with traction by a transumbilical bowel grasper. Further mobilization of the upper pole and renal hilar dissection are undertaken by a transumbilically inserted Harmonic scalpel (Ethicon)—in addition to the gastroscope-deployed snare and flexible graspers. Using visualization from the gastroscope, an EndoPath laparoscopic 45-mm stapler (Ethicon) was used to transect the ureter followed by the renal hilum in an en bloc fashion (Fig. 1F). 592
After completion of renal mobilization, the peritoneal window at the gastroscope insertion site was enlarged. The gastroscope was then exchanged for an EndoCatch bag (Covidien, Mansfield, MA), which was deployed through the rectotomy following the course established by the gastroscope dissection. The EndoCatch bag positioning was guided by visualization through the periumbilical port, and the entrapped kidney was removed intact from the rectum (Fig. 2A to C). The nasal speculum was placed in the anus, and the rectotomy was closed from the outside primarily with interrupted 2-0 Vicryl (polyglactin, Ethicon, Somerville, NJ; Fig. 2D).
Data Collection Operative time (from pneumoperitoneum to closure, minutes) and transrectal access time (minutes) was recorded. The harvested specimen was measured (Fig. 2E), in addition to cadaver weight, transrectal access and operative time, and dimensions of the removed kidney. Cadaver weight and height were used to calculate body mass index (BMI, kg/m2).
RESULTS All cases of transrectal hybrid NOTES nephrectomy (2right/2-left) were successfully completed without conversion to multiport laparoscopy or open surgery. Transrectal access through the submucosal tunnel was able to reach the targeted side in all cadavers with guidance by the transumbilical laparoscope monitoring. Right-sided access into the retroperitoneum was more straightforward, with a wider gap for dissection between the peritoneum and the iliac vessels and ureter than the left. Consequently, transabdominal visual guidance was reUROLOGY 80 (3), 2012
ferred to less on the right side. Entry into the peritoneum facilitated better landmark identification and facilitated renal mobilization and hilar ligation. In all cases, transrectal deployment of the specimen entrapment bag was successful, leading to intact specimen extraction. There were no difficulties with specimen extraction in any of our cases. Median cadaver weight was 77 kg (range 70-85 kg); median BMI (kg/m2) was 30.1 (range 25.6-31.2). Median total operative time was 175 minutes (range 150-210 minutes), with a median transrectal access time of 36 minutes (range 24-47 minutes), and ⬎75% of the procedure being performed through the transrectal access. Median kidney length, width, and thickness (range, cm) were 11.3 (10-12), 5 (4.5-6), and 3.8 (3-4.5), respectively.
COMMENT Since introduction of the concept of natural orifice surgery by Gettman et al10 in 2002 and by Kalloo et al3 in 2004, an expanding range of general surgical and urologic surgical procedures have been performed using a variety of different entry points in a porcine model.9-19 In humans, Breda et al20 were able to deliver a nonfunctioning kidney through the vagina and Gill et al21 reported 10 clinical vaginal extractions of kidney after multiport laparoscopic nephrectomy. Sotelo et al7 and Kaouk et al22 reported hybrid and pure transvaginal NOTES radical nephrectomy in humans, respectively. Our transrectal approach allows a larger colonic access point with easier closure afterward without the need to deploy endoscopic clips.9,23 This has the advantage of access to retroperitoneal and intraperitoneal organs with extraction of larger specimens/organs using larger trocars and deployed rigid and semirigid instruments. The approach is applicable to men and women, avoiding violation of sexual and reproductive organs. Given that the dissection through the pelvis was posterior to the rectum, we avoided contact with the posterior aspects of the prostate and seminal vesicle. Furthermore, the peritoneotomy is made cephalad to intraperitoneal structures, such as the fallopian tubes, which are displaced anteriorly in the overlying peritoneum during the initial dissection by the gastroscope. The key maneuver in the transrectal access is entry into the avascular plane anterior to Waldeyer’s fascia to facilitate cephalad dissection along the presacral space— deviation from this plane posteriorly would result in bleeding and potential injury to sacral vessels and hypogastric nerves, and anteriorly, would create mesorectal bleeding. The major drawback for the transrectal approach is potential for bacterial contamination of the abdomen. There are reports of a small series of animal survival models using different access and sterilization techniques with promising preliminary results revealing good healing of colonic incision sites. Fong et al24 performed transcolonic NOTES abdominal exploration on 6 pigs—all survived for the study duration of 2 weeks, at which time necropsy was performed for inflammatory UROLOGY 80 (3), 2012
infiltrates, abscesses, mucosal ulcerations, and serositis at colonic closure sites; however, there was no evidence for microscopic peritonitis in any of the pigs. Similar findings were reported by Wilhelm et al25 who performed transcolonic NOTES abdominal exploration in 5 pigs survived to necropsy at 10 days with no signs of peritonitis, infection, or significant adhesions. In our experimental transrectal preclinical and cadaveric NOTES studies, we have recapitulated the hybrid approach used by our institutional review board-approved clinical trials of NOTES (NCT00531219, NCT00530998)26,27 using the transumbilical trocar to guide our transrectal access, assist in renal mobilization, and for deployment of the stapler. Indeed, more than 75% of the procedure is performed via instrumentation inserted via the natural orifice, therefore, fulfilling criteria for hybrid NOTES, as proposed by Box et al.28 Of the 8 steps outlined in Table 1, 5 are purely transrectal (Step 2-access, Step 3-dissection up to retroperitoneum, Step 4-creation of peritoneal window, Step 7-specimen entrapment and extraction, and Step 8-rectotomy closure); two steps are transabdominal (access, ureteral and hilar ligation); and 1 step is mixed (Step 5-renal mobilization-mostly transrectal, from take down of the white line, medial visceral rotation, posterior dissection were transrectal, with the upper pole anterior dissection being mostly transabdominal and hilar skeletalization being mixed). From the median operative time of 175 minutes, the 2 purely transabdominal steps (obtaining laparoscopic access and ureteral and renal hilar ligation) took no more than 15 minutes in all cases performed. Indeed, as technology continues to evolve, a purely transrectal NOTES approach using a mixed transperitoneal-retroperitoneal (as demonstrated in our study), or exclusively retroperitoneal dissection may be possible. When compared to our reported porcine experiments,9 a human cadaveric approach posed more challenges and instrument limitations; longer torso, thicker perinephric fat and Gerota’s fascia, complex renal hilar anatomy, and inability to achieve optimal abdominal cavity pneumoperitoneum due to abdominal wall rigidity. Right-sided transrectal access was also more straightforward. The presence of the sigmoid colon on the left side, overlying the pelvic inlet, decreases room to maneuver between the peritoneum and the iliac vessels compared to the right side, and we noted that we referred to the transumbilical laparoscope more to assist in positioning guidance. As a matter of general principle, we considered maintaining the peritoneum medially as a critical landmark as we exited the pelvis and transited the iliac vessels with the gastroscope. The next important landmark was identification of the ureter, coursing laterally over the iliac vessels, which we traced toward the kidney. The dissection and mobilization of the kidney, especially of the upper pole, which is in a more posterior plane than the lower pole, was more challenging. However, this issue was addressed by using the Kittner and harmonic scalpel 593
to take down the upper pole attachments anteriorly, and by using the bowel grasper or Kittner dissector to place medial traction while using the articulation of the endoscope with deployed snare to take down posterior attachments. The hybrid approach allowed effective intra-abdominal triangulation combinations (snare and grasper through the gastroscope and Kittner transumbilically, or harmonic scalpel transabdominally with a transrectal snare through the gastroscope, for instance). Significant challenges locating identifiable landmarks and directional guides were faced and were addressed by transabdominal laparoscope monitoring. There were no difficulties with specimen extraction, given the easy transit of the entrapped specimen through the peritoneotomy into the pelvis and the presacral space. The distensibility of the avascular, areolar plane in the presacral space in the human pelvis facilitates the extraction. In this study with the cadaveric model, our median operative time of 175 minutes and transrectal access time of 36 minutes is similar to the total operative and transrectal access times of 180 and 30 minutes, respectively, which we had previously reported for NOTES hybrid transrectal nephrectomy in the porcine model.9 Our reported times compare to those reported by other groups for NOTES nephrectomy—with a mean operative time of 170 minutes in transvaginal cadaveric models29 and 420 minutes in human transvaginal nephrectomy.22 Although it does replicate anatomy with its posed challenges, the cadaveric model has its drawbacks— especially for the abdominal wall rigidity, hence, the inability to achieve ideal pneumoperitoneum. Additionally, the nondiscriminatory appearance of cadaveric tissue challenged organ and structure identification, which was helped by laparoscopic monitoring with the hybrid approach. Furthermore, despite the median BMI being in the obese range, with potential implications regarding abdominal and retroperitoneal fat, and given the limitations of the cadaveric model with respect to tissue/landmark identification, we demonstrated that using a hybrid NOTES approach we were able to navigate to the kidney and then remove it intact. As proof of principle for the challenges of human anatomy, demonstration of the feasibility of our approach is critical before proceeding with further study.
CONCLUSIONS Transrectal hybrid NOTES nephrectomy in the cadaveric model is feasible and reproducible with intact specimen extraction and acceptable operative times. Preclinical survival studies are requisite to assess sterility and complications of this procedure before we bridge this new surgical concept to human clinical trials. References 1. Pearl JP, Ponsky JL. Natural orifice translumenal endoscopic surgery: a critical review. J Gastrointest Surg. 2008;12:1293-1300.
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