Techniques for transgastric access to the peritoneal cavity

Gastrotomy Healing After Transgastric Peritoneoscopy: A Randomized Study in a Pig Model

INTRODUCTION

Reliable closure and infection prevention are the main barriers for implementation of pure transgastric peritoneoscopy. The primary aim of this study was to assess healing of over the scope clip (OTSC) closed gastrotomies.

MATERIALS AND METHODS

Pure transgastric peritoneoscopy was performed in 7 pigs. The pigs were randomized to 14 or 28 postoperative days (POD) of follow-up. Decontamination of the access route was performed before instrumentation. A full necropsy was performed. Closure was evaluated with histopathological examination of excised gastrorrhaphies.

RESULTS

Three pigs were allowed 14 POD of follow-up, and 4 pigs were allowed 28 POD of follow-up. Survival was achieved in 6 of the 7 animals; 1 pig was euthanized due to diffuse peritonitis. Based on our definition, full-thickness healing had only been achieved in a single pig allowed 28 POD. With respect to clinical relevancy, full-thickness healing was deemed achieved in 4 of 6 pigs completing follow-up and in all pigs allowed and surviving 28 POD. Access required repeated punctures and the use of several endoscopic instruments.

CONCLUSIONS

Full-thickness healing of the gastrotomy was only found in a single case when adhering to the per protocol definition. Endoscopic ultrasonography-guided access was difficult. It lacks reproducibility and needs refinement. Despite a combined decontamination regimen, infectious complications still occurred.

Innovations in minimally invasive surgery: lessons learned from translational animal models

PURPOSE

Animal models are key elements of surgical research and promotion of new techniques. Inanimate models, anatomical specimens, and living animals are all necessary to solve the various problems encountered by the advent of a new surgical technique. The development of Natural Orifice Transluminal Endoscopic Surgery (NOTES) procedures is a representative model.

METHODS

Over 400 experimental procedures were performed in inanimate models, ex vivo tissues and animals to solve all problems faced by the development of NOTES surgery: peritoneal access, gastrotomy closure, exposure, retraction, dissection as well as education to start this new procedure.

RESULTS

The successive use of all models allows to identify the ideal solution for each problem and to precisely define the safest and most reliable option to apply the new technique in patients. It allowed to perform the first transvaginal and transgastric cholecystectomy in patients in a safe way.

CONCLUSION

Animal experimentation remains necessary as even sophisticated computer-based solutions are unable to model all interactions between molecules, cells, tissues, organisms, and their environment. Animal research is required in many areas to validate new technologies, develop training, let alone its major goal (namely to avoid using patients for experimentation) which is to be the first "model" for the surgeon.

Comparison of anterior transgastric access techniques for natural orifice translumenal endoscopic surgery

BACKGROUND

The advancement of natural orifice translumenal endoscopic surgery (NOTES) into clinical practice is dependent on its safety, efficacy, and efficiency. Access is the obligatory first step in NOTES and serves as a surrogate to technical difficulties associated with this novel surgical approach. This study aimed to compare endoscopic transgastric access techniques in terms of safety, reproducibility, and efficiency.

METHODS

Seven variations for anterior transgastric NOTES access were evaluated with female domestic swine. After marking of an anterior site, electrocautery was used to create a small gastrotomy, followed by balloon dilation and entry into the peritoneal cavity. Methodologic variations incorporated the use of guidewires, electrocautery and dilation combined within a single device, support tubes, and dilation without electrocautery. Access times were recorded, and tissue injury was evaluated.

RESULTS

In 70 access attempts, the most serious complication was bleeding from the gastroepiploic vessel, controlled with electrocautery. High variability in access times was prevalent with almost all the access techniques.

CONCLUSIONS

This study supports the presumption that an anterior transgastric access technique for NOTES procedures is safe. The use of a wire to mark the site and another wire to retain the gastrotomy provided safe, efficient, and reproducible transgastric access. Comparison with laparoscopy exposed the disparity in technical challenges facing NOTES, suggesting that new technology and further refinement in methodology are required for NOTES to be clinically relevant.

Clinical applications of submucosal endoscopy

PURPOSE OF REVIEW

Submucosal endoscopy with mucosal flap (SEMF), a new diagnostic and therapeutic intervention of flexible endoscopy, has been examined from the perspective of developmental laboratory work, procedural details, and results of early clinical experiences.

RECENT FINDINGS

Diagnostic natural orifice translumenal endoscopic surgery (NOTES) procedures, endolumenal achalasia myotomy, and submucosal tumor excision have been clinically performed with a SEMF method. The outcomes of these procedures were equivalent to standard surgery but with reduced morbidity. Some were accomplished under conscious sedation within the endoscopy unit.

SUMMARY

The SEMF procedure was originally developed to provide safe access to the peritoneal cavity for NOTES procedures. In the SEMF method, the submucosal layer is endoscopically tunneled and the resultant space is used as an endoscopic path into deeper layers of the gut wall and an offset exit to the peritoneal cavity. Key to the method is the overlying mucosa which serves as a sealant flap minimizing the risk of soiling a body cavity with lumenal contents and the ease by which the entry point into the submucosal working space can be closed. Positive outcomes of the early SEMF clinical experiences validate that the submucosa can be transformed into a promising novel working space for flexible endoscopy.

A 2-microm continuous-wave laser system for safe and high-precision dissection during NOTES procedures

INTRODUCTION

Lasers 2-microm in wavelength offer efficient tissue cutting with limited thermal damage in biological tissue.

OBJECTIVE

To evaluate the dissection capabilities of a 2-microm continuous-wave laser for NOTES procedures.

METHODS AND PROCEDURES

We conducted 18 acute animal experiments. Group 1 (three animals): transcolonic access to the peritoneal cavity (15-W transcolonic laser puncture, balloon dilation over the laser probe). Group 2 (six animals): transcolonic access with needle-knife puncture and balloon dilation. Group 3 (three animals): transgastric access to the peritoneal cavity (similar technique as group 1) followed by laser-assisted dissection of the kidney. In one animal of group 3, a therapeutic target (hematoma) was created by percutaneous puncture of the kidney. Group 4 (six animals): transgastric access (similar to the technique of group 2).

RESULTS

Translumenal access to the peritoneal cavity was achieved in 2-3 min in group 1 (significantly shorter than with the needle-knife-assisted technique, 4-5 min, p=0.02) and in 7-10 min in group 3 (compared to 6-17 min in group 4, p=0.88). In group 3, laser dissection of the parietal peritoneum and of perinephric connective tissue allowed access to the retroperitoneum with complete removal of a blood collection in the animal with puncture trauma. Laser dissection demonstrated good maneuverability, clean and rapid cutting, and excellent hemostasis. Peritoneoscopy and necropsy showed no damage of targeted tissue and surrounding organs.

CONCLUSIONS

The 2-microm continuous-wave laser system showed promising capabilities for highly precise and safe dissection during NOTES procedures.

Gastric wall healing after NOTES procedures: closure with endoscopic clips provides superior histological outcome compared with threaded tags closure

BACKGROUND

Closure of the transgastric access to the peritoneal cavity is a critical step in natural orifice transluminal endoscopic surgery (NOTES).

OBJECTIVE

To perform a direct comparison of the histological healing post clips and threaded tags (T-tags) closure after transgastric NOTES procedures.

DESIGN AND INTERVENTION

Twelve survival porcine experiments. After standardized endoscopic gastric wall puncture, balloon-dilation, and transgastric peritoneoscopy, closure of the gastric wall was performed with either clips or T-tags. Necropsy at 14 days was performed for histological evaluation of 2-mm interval transversal cross sections of the gastrotomy site.

MAIN OUTCOME MEASUREMENTS

Histological healing of the gastric wall opening.

RESULTS

Endoscopic closure of the gastrotomy was successfully achieved in all 12 animals, followed by an uneventful 2-week clinical follow-up. Transmural healing was seen in 3 (75%) animals after clip closure compared with only 1 (12.5%) in the group with T-tag closure (P = .06). Gastric wall muscular bridging was observed in 4 (100%) animals with clip closure compared with only 1 (12.5%) in the group with T-tag closure (P = .01).

LIMITATIONS

Animal model with short-term follow-up.

CONCLUSIONS

Endoscopic clip closure results in a layer-to-layer transmural healing of the gastric wall. In contrast, T-tag gastric wall plication impairs gastric layer bridging. These findings might guide the future design of new endoscopic devices and techniques for gastrotomy closure after NOTES procedures.

Transgastric cholecystectomy: From the laboratory to clinical implementation

After the first report by Kalloo et al on transgastric peritoneoscopy in pigs, it rapidly became apparent that there was no room for an under-evaluated concept and blind adoption of an appealing (r)evolution in minimal access surgery. Systematic experimental work became mandatory before any translation to the clinical setting. Choice and management of the access site, techniques of dissection, exposure, retraction and tissue approximation-sealing were the basics that needed to be evaluated before considering any surgical procedure or study of the relevance of natural orifice transluminal endoscopic surgery (NOTES). After several years of testing in experimental labs, the revolutionary concept of NOTES, is now progressively being experimented on in clinical settings. In this paper the authors analyse the challenges, limitations and solutions to assess how to move from the lab to clinical implementation of transgastric endoscopic cholecystectomy.

Evaluation of endoscopy in localizing transgastric access for natural orifice transluminal endoscopic surgery in humans

BACKGROUND

To date, transgastric access in humans for natural orifice transluminal endoscopic surgery (NOTES) has been poorly evaluated.

OBJECTIVE

To compare endoscopic visualization of the transgastric access point with the laparoscopically defined ideal entrance to the peritoneal cavity.

DESIGN

Prospective pilot study in humans.

SETTING

Single tertiary-care center.

PATIENTS

This study involved 31 patients referred for laparoscopic cholecystectomy.

INTERVENTION

Access points were marked by endoscopy alone, endoscopy combined with diaphanoscopy, and endoscopy after pneumoperitoneum. Points were correlated with a laparoscopically visualized, previously defined ideal access area.

MAIN OUTCOME MEASUREMENTS

To choose the appropriate access point within the laparoscopically defined ideal access area to the peritoneal cavity away from major vessels and adjacent organs, by using endoscopy and to establish landmarks for the endoscopist, look for a learning curve, and identify potential problems.

RESULTS

The percentage of access points within the laparoscopically defined ideal area was 35.5% with endoscopy alone, 13.8% using the diaphanoscopy method, and 45.2% after transcutaneous pneumoperitoneum. A safe access point (> or = 3 cm from major gastric vessels) could be achieved with the 3 techniques in 83.9%, 65.5%, and 87.1% of patients, respectively. A positive learning curve for endoscopic localization was identified before (P = .008) and after (P = .014) pneumoperitoneum. Virtual complications were greater in obese patients.

LIMITATIONS

This was a small pilot study with hypothetical complications and problems, because actual transgastric access was not performed. The criteria for an ideal access area were very strict.

CONCLUSION

Endoscopy, especially with the use of pneumoperitoneum, can reliably locate a safe transgastric entrance point. However, the endoscopically chosen site correlates poorly with the ideal laparoscopically determined site for transgastric access.

Natural orifice translumenal endoscopic surgery 2009: what is the future for the gastroenterologist?

PURPOSE OF REVIEW

In order to predict whether the gastroenterologist will have a role in the rapidly developing field of natural orifice translumenal endoscopic surgery (NOTES), it is helpful to examine the new developments in this field. Our goal in this review is to examine the recent developments in the field and study the gastroenterologists' role to best make this prediction.

RECENT FINDINGS

Perhaps the most significant development in the field of NOTES has been the favorable patient and physician preferences for NOTES. There is evidence that patients would prefer NOTES cholecystectomy to laparoscopic cholecystectomy. The most common reason for this choice appears to be the lack of pain and visible scar. Another very significant development has been the reality of human NOTES procedures. Multiple centers have reported human NOTES procedures, including transgastric appendectomies, transgastric liver biopsies, transgastric tubal ligation and transvaginal cholecystectomy without major complications. Gastroenterologists' expertise with flexible endoscope was critical in the above cases. Recently, a few publications have also shown how gastroenterologists with expertise in endosonography can have a role in affirming safe access.

SUMMARY

Although no one can predict with certainty where the field of NOTES will be in 1 year, it seems likely that gastroenterologist involvement will be necessary and advancements in this field will be applicable and diffuse into our daily practice.

[The future of gastrointestinal therapeutic endoscopy: NOTES]

Natural orifice translumenal endoscopic surgery (NOTES) allows access into the peritoneal cavity with a flexible endoscope, through the wall of the digestive or urogenital tracts. NOTES can be combined to laparoscopic surgery in so-called << hybrid >> techniques. In the absence of any incision of the abdominal wall, NOTES procedures provide perfect cosmetic results, with virtually no risk of parietal complications, and with decreased postoperative pain. NOTES could particularly benefit to overweight patients and to patients receiving intensive or palliative care. Most NOTES studies have been performed on animal models, with great interest for both transgastric and transpelvic approaches. Successful NOTES peritoneoscopy, hysterectomy, oophorectomy, tubal ligation, gastrojejunal anastomosis, cholecystectomy, splenectomy, nephrectomy, and abdominal-wall hernia repair have been described. In human studies, the transvaginal route is preferred. NOTES clinical research focuses on low-morbidity procedures, such as cholecystectomy, appendectomy, and peritoneoscopy. Indirect benefits are expected from this research, with possible technological innovations in the field of endoscopic instrumentation (including sutures, anastomosis, traction and triangulation). Overall, NOTES is believed to make evolve both interventional endoscopy and minimally invasive surgery.

[Training design and improvement of technical skills in the transvaginal cholecystectomy (NOTES)]

INTRODUCTION

The current surgical scenario of the surgery through natural orifices or <<no-scar surgery>> requires acquiring new technical skills by the surgeon. We introduce the initial experience of the Minimally Invasive Surgery Centre Jesús Usón (MISCJU) in the design and setting-up of a surgical training programme using the the natural orifices approach for the acquisition of surgical skills and abilities, based on the preliminary trials in simulators and a pig model.

MATERIAL AND METHODS

After initial training, using a laparoscopic pelvic-trainer, 7 female pigs, with weights between 35-40 kg, were operated on. The transvaginal approach was completed using a one-channel gastroscope in all the animals. After accessing the abdomen, the abdominal cavity was explored, and the surgery was concluded with the endoscopic cholecystectomy.

RESULTS

Endoscopic cholecystectomy was successfully completed in 6 cases. In one of the animals, the procedure was stopped because of technical problems regarding the endoscope leaning to one end. The average surgical time was 107.14 min (range, 80-150 min). The transvaginal approach enabled the abdominal to be explored and the dissection, ligature and section of the cystic duct and the cystic artery. After cholecystectomy, the gallbladder was extracted through the vagina. After the procedure necropsy did not reveal intra-abdominal lesions or intraoperative complications.

CONCLUSIONS

The pure transvaginal cholecystectomy is a feasible and reproducible procedure in the animal model. A systematized training model, which includes physiopathology knowledge as well as technical knowledge, in order to translate these procedures to the clinical practice in a safe way, is needed.

Challenges and lessons learned from NOTES cholecystectomy initial experience: a stepwise approach from the laboratory to clinical application

BACKGROUND/PURPOSE

The initial idea behind natural orifice transluminal endoscopic surgery (NOTES) was that of an incisionless surgery. NOTES cholecystectomy is a good model of human ingenuity and technological advance. NOTES cholecystectomy in a human being was performed at our institution after extensive laboratory work in live pig models. In this process we gained helpful information related to NOTES cholecystectomy.

METHODS

More than 250 cholecystectomies in pigs have been performed. From May 2007 to November 2008 a total of 10 and 6 transvaginal and transgastric human cholecystectomies, respectively, have been performed.

RESULTS

The procedure was successful in all patients, with a mean operative time of 120 min. There were no intraoperative or postoperative complications. Patients recovered promptly after surgery and had minor postoperative pain. They were discharged on the second postoperative day.

CONCLUSIONS

The advantages of laparoscopy appeared to be enhanced by this approach: patients had minor postoperative pain and minimal scarring. This stepwise experience in the cholecystectomy procedure is an important first step in the development of methods and devices to enable the evaluation of potential incisionless NOTES surgery. Additional research and comparison studies are needed for further improvement in order to provide NOTES procedures to a wider range of patients.

Natural orifice translumenal surgery: from scales to symphonies

PURPOSE OF REVIEW

Natural orifice transluminal endoscopic surgery is a new therapeutic procedure that combines surgical and endoscopic skills. Although not currently widely used, it is gaining momentum both in the animal laboratory and in human case reports.

RECENT FINDINGS

To date, 15 procedures have been successfully performed on humans worldwide. These included appendectomies (eight), liver biopsies (three), tubal ligation (one), and cholecystectomies (three). Numerous other procedures, using hybrid techniques that combine natural orifice transluminal endoscopic surgery technology with alternative conventional laparoscopic techniques, have been described in human clinical trials. In this review, we will discuss the potential benefits of this procedure over conventional surgical interventions, briefly review the major challenges to the technique (access, spatial orientation, anastomosis, and closure), and point out the technological limitations that severely handicap its potential.

SUMMARY

Despite the widespread interest in this technology, there are a lot of shortcomings: limitations in equipment, lack of clinical outcome data, and absence of randomized trials that compare it with alternative conventional surgical interventions. Nevertheless, it is crucial to remember that we have just started the evaluation process for this new exiting technology, and that, clearly, the best is yet to come.