Peroral transgastric organ resection: a feasibility study in pigs

Advances in experimental studies of peroral transgastric endosurgery

Since peritoneoscopic surgery was first carried out, this minimal trauma surgery has become widely applied. Recently, endoscopic surgeries from a natural orifice into the abdominal cavity have become a reality, especially for transgastric surgery of the abdomen. Various animal studies, such as those involving transgastric endoscopic gastrojejunostomy and cholecystectomy, trans-gastric abdominal tissue biopsy, transgastric cholecystic surgery, transgastric ligation of fallopian tubes, transgastric endoscopic spleen resection, endoscopic appendectomy and transgastric peripancreatic necrosis debridement, have been reported. Some of these surgical procedures have been performed in patients, indicating the emergence of this form of minimal trauma abdominal surgery. However, these surgical techniques are still at a primary stage. Further coordination between specialists should help overcome any remaining deficiencies and enable perfection of this technique, leading to its eventual clinical application.

Taking NOTES: translumenal flexible endoscopy and endoscopic surgery

PURPOSE OF REVIEW

To review the current state of natural orifice surgery and examine the concerns, challenges, and opportunities presented by translumenal research.

RECENT FINDINGS

Translumenal endoscopic procedures have been the focus of extensive research. Researchers have reported natural orifice translumenal endoscopic surgery in a swine model in several areas involving the abdominal cavity. Diagnostic procedures have included endoscopic peritoneoscopy, liver biopsy, lymphadenectomy, and abdominal exploration. Several gynecologic procedures including tubal ligation, oophorectomy, and partial hysterectomy have been demonstrated using current commercial endoscopes. Gastrointestinal surgical procedures, including gastrojejunostomy, cholecystectomy, splenectomy, and distal pancreatectomy have been performed successfully via transgastric and/or transcolonic approaches. There have been no studies of natural orifice translumenal endoscopic surgery procedures published in humans. While fundamental questions about the emerging technology have not been scrutinized, limitations of the large animal model will pose a challenge to the development of large randomized trials.

SUMMARY

While natural orifice translumenal endoscopic surgery may represent a paradigm shift and may offer significant benefits to patients, rigorous testing of the techniques is lacking and current data have been drawn from case series.

Surgery insight: natural orifice transluminal endoscopic surgery--an analysis of work to date

Traditional flexible endoscopy has been limited to the confines of the gastrointestinal lumen; however, recent developments involving transluminal access to intra-abdominal structures hold the potential to revolutionize flexible endoscopy. Over the past few years various studies have detailed techniques that intentionally breach the lumen and provide endoscopic access to the peritoneal cavity for diagnostic and therapeutic procedures. Unlike standard surgical approaches, which require incisions to be made in the abdominal wall, natural orifice transluminal endoscopic surgery (NOTES) avoids the need for abdominal incisions and can offer specific advantages to select patient populations. Animal models have been used to demonstrate the possible applications of NOTES, including transgastric peritoneoscopy, tubal ligation, gastrojejunostomy, partial hysterectomy, oophorectomy, and transcolonic exploration, liver biopsy and cholecystectomy. In this Review, we highlight important advances in NOTES since it was first described and analyze the hazards and potential benefits associated with this innovative approach.

Current status of natural orifice translumenal surgery

Translumenal access to the peritoneal cavity will have definite advantages in situations whereby the transcutaneous route into the peritoneal cavity is not optimal. For example, transgastric approach may decrease the risk of postoperative wound complications in patients who have marked obesity, as well as in patients who have anterior abdominal wall infection or severe scarring. Natural orifice translumenal surgery provides an exciting opportunity to improve surgical intervention using the skills, imagination, and ingenuity of endoscopists and endoscopic surgeons.

NOTES: a gastroenterologist's perspective

Once in a few decades in science or medicine, an idea emerges that is so powerful that it changes forever how we think about the field. Such is the case of natural orifice transluminal endoscopic surgery (NOTES). NOTES has yet to prove its value in patients. However, having challenged one of the most fundamental and deeply entrenched dogmas in surgery and endoscopy, many of us feel that "we will never be the same again." In this article I will discuss the implications of this paradigm shift and suggest strategies for both gastroenterologists and surgeons that will allow us to test its full potential.

Hybrid minimally invasive surgery--a bridge between laparoscopic and translumenal surgery

BACKGROUND

The peroral transluminal approach to the peritoneal cavity appears safe, feasible, and may further reduce the invasiveness of surgery. However, flexible endoscopes have multiple limitations inside the peritoneal cavity, which can potentially be overcome by blending the use of both a laparoscope and a flexible upper endoscope--a hybrid approach. The goal of the present study was to evaluate a hybrid minimally invasive technique for cholecystectomy in a porcine model.

METHODS

Hybrid cholecystectomies were performed in acute experiments on 50-kg pigs under general anesthesia. Pneumoperitoneum was created with a Veress needle, and a laparoscopic 10-mm port was inserted. Under laparoscopic observation, the gastric wall incision was done with an endoscopic needle-knife and sphincterotome, and the upper endoscope was advanced into the peritoneal cavity. A laparoscopic 10-mm port was inserted into the right upper quadrant of the abdomen for gallbladder traction to facilitate exposure of the cystic duct and artery. Via the biopsy channel of the flexible endoscope, and using a knife with an isolated tip, a needle knife, and clips, both the cystic duct and artery were identified, clipped, and transected. The gallbladder itself was then dissected and retracted through the mouth, and the gastric wall incision was closed with endoscopic clips.

RESULTS

Five hybrid cholecystectomies were performed without complications. The laparoscopic port enabled a stable pneumoperitoneum, good traction and counter-traction, and improved spatial orientation and visualization. Necropsy did not reveal any intraperitoneal complications.

CONCLUSIONS

The hybrid approach increases safety of initial gastric puncture and gastric wall incision, improves orientation and navigation of the flexible endoscope inside the peritoneal cavity, simplifies peroral transgastric cholecystectomy, and could be used to decrease invasiveness of laparoscopic surgery and to facilitate development and clinical introduction of transgastric endoscopic procedures.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s00464-007-9329-2) contains supplementary material, which is available to authorized users.

Rapid Communication: Transvaginal Single-Port NOTES Nephrectomy: Initial Laboratory Experience

BACKGROUND AND PURPOSE

Natural orifice translumenal endoscopic surgery (NOTES) using purpose-built equipment has never been applied to urologic surgery. Herein, we present our initial experience with a trans-vaginal single-port NOTES nephrectomy.

METHODS AND RESULTS

An acute experiment was performed in a female farm pig. A single 12-mm trocar was placed in the midline and the TransPort Multi-Lumen Operating Platform (USGI Medical, San Clemente, CA) was passed transvaginally. This flexible device has four working channels and can be locked into position, thereby creating a rigid multitasking platform that allows two-handed tissue manipulation. Dissection was performed using an endoscopic needle knife and a tissue grasper for retraction. Via the 12-mm port, the renal artery and vein were taken separately with a vascular EndoGIA and standard laparoscopic titanium clips, respectively. The kidney was placed in a 10-mm EndoPouch retriever and removed intact via the vagina. The total operative time was 300 minutes.

CONCLUSION

Transvaginal NOTES nephrectomy can be accomplished in a porcine model. Additional testing on survival animals is necessary to validate this approach.

[The present and future status of "scarless" surgery]

The concept of scarless surgery aims at further minimization of diagnostic and therapeutic interventions. Based on the success of flexible gastroenterological endoscopy and laparoscopic surgery, it combines their advantageous approaches in a synergistic manner. Animal experiments have achieved encouraging results in respect to the feasibility of various types of interventions in the peritoneal and retroperitoneal cavity. Further studies and improvement of instruments will have to prove the practicality and superiority of this concept for medical outcome and efficiency compared to present standards of practice in the potential fields of application. The replacement of certain minimally invasive procedures with scarless intervention techniques seems reasonable, as do new fields of application. After further improvement of the methodology, adequate organization, infrastructure, and teaching structures will have to be developed. If they succeed, the concept of scarless surgery can expect a promising future.

Transvesical thoracoscopy: a natural orifice translumenal endoscopic approach for thoracic surgery

BACKGROUND

Recently there has been an increasing enthusiasm for using natural orifices translumenal endoscopic surgery (NOTES) to perform scarless abdominal procedures. We have previously reported the feasibility and safety of the transvesical endoscopic peritoneoscopy in a long-term survival porcine model as useful for those purposes. Herein, we report our successful experience performing transvesical and transdiaphragmatic endoscopic approach to the thoracic cavity in a long-term survival study in a porcine model.

METHODS

Transvesical and transdiaphragmatic endoscopic thoracoscopy was performed in six anesthetized female pigs. A 5 mm transvesical port was created on the bladder wall and an ureteroscope was advanced into the peritoneal cavity. After diaphragm inspection, we introduced through the left diaphragmatic dome a ureteroscope into the left thoracic cavity. In all animals, we performed thoracoscopy as well as peripheral lung biopsy. Animals were sacrificed by day 15 postoperatively.

RESULTS

We easily introduced a 9.8 Fr ureteroscope into the thoracic cavity that allowed us to visualize the pleural cavity and to perform simple surgical procedures such as lung biopsies without complications. There were neither respiratory distress episodes nor surgical complications to report. Postmortem examination revealed complete healing of vesical and diaphragmatic holes, whereas no signs of infection or adhesions were observed in the peritoneal or thoracic cavities.

CONCLUSION

This study demonstrates the feasibility of transvesical thoracoscopy in porcine model. However, although this study extends the potential applications of NOTES to the thoracic cavity, new instruments and further work are needed to provide evidence that this could be translated to humans and with advantages for patients.

Initial experience with a novel endoscopic device allowing intragastric manipulation and plication

BACKGROUND

Current developments in intraluminal and transluminal natural orifice surgery are limited by issues of access, tissue manipulation, and secure tissue approximation/closure. This report describes an initial laboratory experience with a novel tissue approximation and suturing device. The device is deployed via a previously described platform and is 6 mm in diameter. Desirable qualities of this tissue approximation/closure device include robust tissue grasping, minimal tissue trauma, fully visualized anchor placement via off-axis needle and anchor deployment, full reloadability without instrument withdrawal, single-operator operating capability, torque-stable manipulability, and operator-controlled tension setting of tissue anchor pairs.

METHOD

The device was trialed in performing several maneuvers in porcine or canine models. The features of the system allowed bimanual tissue manipulation, full-thickness tissue approximation and plication, and secure closure of an ex vivo gastrotomy hole similar to that used during transluminal surgical interventions.

CONCLUSIONS

This device appears to offer promise in achieving more complex endoluminal and potentially transluminal tasks, including secure suture closure of tissue defects and access holes. As such, devices of this type may prove useful in addressing some of the identified barriers to further development of natural orifice surgical intervention. Further investigation of the qualities and capabilities of this device in these settings is warranted.

Transcolonic endoscopic abdominal exploration: a NOTES survival study in a porcine model

BACKGROUND

Published reports on NOTES (natural orifice transluminal endoscopic surgery) have thus far been limited to the transgastric method.

OBJECTIVE

The aim of this study was to assess the transcolonic approach as a means of accessing and systematically exploring the abdominal cavity in a survival study design.

DESIGN

Six pigs were placed under general anesthesia and were prepped with multiple tap-water enemas, followed by instillation of a cefazolin suspension and a povidone-iodine lavage. Equipment was prepared with a high-level chemical disinfection, and an aseptic technique was used. An incision was made in the anterior colonic wall, and abdominal exploration was performed by using a double-channel endoscope. The incision was subsequently closed with endoscopic clips, endoloops, or a prototype closure device.

PATIENTS

Six female Yorkshire pigs that weighed 25 to 30 kg.

RESULTS

Stomach, liver, gallbladder, spleen, small bowel, colon, and peritoneal surfaces were identified in all animals in less than 3 minutes. The lower pelvic organs were not consistently visualized. All animals were alive for 14 days without apparent complications. At necropsy, the colonic incision sites were completely closed and appeared well healed. Microscopic inflammatory changes were seen at the closure site in all animals, including microabscesses. Incision-related adhesions were identified in 4 of 6 animals.

CONCLUSIONS

This study demonstrated the use of a novel transcolonic approach to successfully access and explore the abdominal cavity. In contrast to the transgastric method, a transcolonic approach provides more consistent identification of structures in the upper abdomen and provides better en face orientation and scope stability. Therapeutic interventions in the upper abdomen, including organ resection, may be more tenable by using a transcolonic method; however, further studies are needed to address issues of sterility and colonic closure.

Third-generation cholecystectomy by natural orifices: transgastric and transvesical combined approach (with video)

BACKGROUND

An isolated transgastric port has some limitations in performing transluminal endoscopic cholecystectomy. However, transvesical access to the peritoneal cavity has recently been reported to be feasible and safe.

OBJECTIVE

To assess the feasibility and the technical benefits of transgastric and transvesical combined approach to overcome the limitations of isolated transgastric ports.

DESIGN

We created a transgastric and transvesical combined approach to perform cholecystectomy in 7 consecutive anesthetized female pigs. The transgastric access was achieved after perforation and dilation of the gastric wall with a needle knife and with a balloon, respectively. Under cystoscopic control, an ureteral catheter, a guidewire, and a dilator of the ureteral sheath were used to place a transvesical 5-mm overtube into the peritoneal cavity. By using a gastroscope positioned transgastrically and a ureteroscope positioned transvesically, we carried out cholecystectomy in all animals.

RESULTS

Establishment of transvesical and transgastric accesses took place without complications. Under a carbon dioxide pneumoperitoneum controlled by the transvesical port, gallbladder identification, cystic duct, and artery exposure were easily achieved in all cases. Transvesical gallbladder grasping and manipulation proved to be particularly valuable to enhance gastroscope-guided dissection. With the exclusion of 2 cases where mild liver-surface hemorrhage and bile leak secondary to the sliding of cystic clips occurred, all remaining cholecystectomies were carried out without incidents.

LIMITATIONS

Once closure of the gastric hole proved to be unreliable when using endoclips, the animals were euthanized; necropsy was performed immediately after the surgical procedure.

CONCLUSIONS

A transgastric and transvesical combined approach is feasible, and it was particularly useful to perform a cholecystectomy through exclusive natural orifices.

Natural orifice translumenal endoscopic surgery (NOTES)

Surgery has rapidly evolved as new technologies are adopted. With the introduction of laparoscopic surgery, patient outcomes have improved, with faster recovery from smaller incisions. In an effort to continually improve these outcomes and offer alternative options to higher risk patients, a number of investigators have proposed the concept of operating in the peritoneal space through natural orifices, obviating the need for any abdominal skin incisions. Natural orifice translumenal endoscopic surgery (NOTES) offers the same advantages as laparoscopic surgery without skin incisions, and possibly without general anesthesia. This article gives a conceptual and technical description of NOTES, discusses its challenges and potential pitfalls, reviews the early efforts at NOTES-specific device development, and predicts potential future directions of this exciting new area of surgery.

Transcolonic endoscopic cholecystectomy: a NOTES survival study in a porcine model (with video)

BACKGROUND

Transgastric cholecystectomy is a natural orifice transluminal endoscopic surgery (NOTES) procedure that has been reported in 2 nonsurvival studies. Both studies detail substantial technical limitations, with only a 33% success rate when limited to 1 gastric incision site, despite the use of a multichannel locking endoscope.

OBJECTIVE

The aim of this study was to evaluate the feasibility and technical limitations of transcolonic cholecystectomy in a survival model.

DESIGN

Animal feasibility study.

INTERVENTIONS

Five pigs, under general anesthesia, were prepared with tap-water enemas, a peranal antibiotic lavage, and a Betadine rinse. A dual-channel endoscope was advanced into the peritoneum through an anterior, transcolonic incision 15 to 20 cm from the anus. After cystic duct and artery ligation, dissection of the gallbladder was achieved by using grasping and cutting instruments. After removing the gallbladder, the colonic incision was closed by using Endoloops and/or endoclips. The animals lived for 2 weeks after the procedure, then they were euthanized, and a necropsy was performed.

RESULTS

All 5 gallbladders were successfully resected. Four of the 5 animals flourished in the postoperative period, with appropriate weight gain. In 1 animal, complete closure of the colonic incision was not possible, and it was euthanized at 48 hours for suspected peritonitis.

CONCLUSIONS

This study reports the first transcolonic organ resection and demonstrates the first successful NOTES cholecystectomy in a survival model. The transcolonic approach provided improved endoscope stability and biliary exposure compared with the transgastric route, and complete incision closure appeared critical for procedural success.