Facilitating gastrotomy closure during natural-orifice transluminal endoscopic surgery using tissue anchors

Transtracheal thoracic natural orifice transluminal endoscopic surgery (NOTES) in a swine model

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) has the potential to be the final frontier in minimally invasive procedures in thoracic surgery. In order for thoracic pleural NOTES to 1 day be ready for clinical trials, each step of the procedure must be independently evaluated for both safety and efficacy. The aim of this study was to evaluate the trachea as a portal of entry for thoracic NOTES.

METHODS

Eight 40-kg swine underwent right thoracic pleuroscopy in a survival model. In order to avoid inadvertent injury to the superior vena cava, endobronchial ultrasound was employed to select the location of airway incision. A 7-mm linear incision was then performed at the chosen location using an endoscopic electrocautery needle knife through a therapeutic flexible videobronchoscope. The mediastinal fat and parietal pleura were then dissected with electrocautery, and complete right pleuroscopy was performed. The tracheal and mediastinal portal of entry were then sealed with 1-2 cc of fibrin sealant. The pigs were kept alive for 21 days postoperatively. Postmortem diagnostic bronchoscopy was performed to assess tracheal healing. All tracheal specimens underwent histologic examination for healing and signs of mediastinal infection.

RESULTS

Thoracic NOTES procedures on all eight pigs were successful. There were no intraoperative complications except for one minor bleeding episode within the mediastinal dissection site which stopped spontaneously. Two pigs died from severe laryngospasm in the early postoperative period. Six pigs survived for 21 days post-procedure and experienced uneventful postoperative courses. Postmortem examination demonstrated complete tracheal healing with appropriate scarring in all pigs.

CONCLUSIONS

The trachea appears to be a safe port of entry for thoracic NOTES procedures in a swine model. Smaller tracheal incisions followed by balloon dilatation are associated with less postoperative morbidity and mortality. Tracheal incisions sealed with fibrin sealant healed rapidly and without signs of mediastinal infection. This procedure represents a work in progress and is not yet ready for human trials.

New laser soldering-based closures: a promising method in natural orifice transluminal endoscopic surgery

BACKGROUND

Complete closure of gastrotomy is the linchpin of safe natural orifice transgastric endoscopic surgery.

OBJECTIVE

To evaluate feasibility and efficacy of a new method of gastrotomy closure by using a sutureless laser tissue-soldering (LTS) technique in an ex vivo porcine stomach.

DESIGN

In vitro experiment.

SETTING

Experimental laboratory.

INTERVENTIONS

Histological analysis and internal and external liquid pressure with and without hydrochloric acid exposure were determined comparing gastrotomy closure with LTS and with hand-sewn surgical sutures.

MAIN OUTCOME MEASUREMENTS

Comparison of LTS and hand-sewn surgical gastrotomy closure. The primary outcome parameter was the internal leak pressure. Secondary parameters were the difference between internal and external leak pressures, the impact of an acid environment on the device, histological changes, and feasibility of endoscopic placement.

RESULTS

The internal liquid leak pressure after LTS was almost twice as high as after hand-sewn surgical closure (416 ± 53 mm Hg vs 229 ± 99 mm Hg; P = .01). The internal leak pressure (416 ± 53 mm Hg) after LTS was higher than the external leak pressure (154 ± 46 mm Hg; P < .0001). An acidic environment did not affect leak pressure after LTS. Endoscopic LTS closure was feasible in all experiments. Histopathology revealed only slight alterations beneath the soldering plug.

LIMITATIONS

In vitro experiments.

CONCLUSIONS

Leak pressure after LTS closure of gastrotomy is higher than after hand-sewn surgical closure. LTS is a promising technique for closure of gastrotomies and iatrogenic perforations. Further experiments, in particular survival studies, are mandatory.

Natural orifice translumenal endoscopic surgery (NOTES(®)): a technical review

INTRODUCTION

The clinical NOTES literature continues to grow. This review quantifies the published human NOTES experience to date, examines instrument use in detail, and compiles available perioperative outcomes data.

METHODS

A PubMed search for all articles describing human NOTES cases was performed. All articles providing a technical description of procedures, excluding cases limited to diagnostic procedures, specimen extraction, fluid drainage or gynecological procedures, were reviewed. Two reviewers systematically cataloged the technical details of each procedure and performed a frequency analysis of instrument use in each type of case. Available outcomes data were also compiled.

RESULTS

Forty-three discrete articles were reviewed in detail, describing a total of 432 operations consisting of transvaginal (n = 355), transgastric (n = 58), transesophageal (n = 17), and transrectal (n = 2) procedures, with 90% of cases performed in hybrid fashion with laparoscopic assistance. Cholecystectomy (84% of cases) was the most common procedure. Analysis of key steps included choice of endoscope, establishment of peritoneal access, dissection, specimen extraction, and closure of the access site. Analysis of instrument use during transvaginal cholecystectomy revealed variation in the choice of endoscope and the technique for establishment of access. A majority of these procedures relied heavily on the use of rigid and transabdominal instrumentation. Closure of the vaginotomy site was found to be well standardized, performed with an open suturing technique. Similar analysis for transgastric procedures revealed consistency in the choice of flexible endoscope as well as access and closure techniques. Perioperative outcomes from NOTES procedures were reported, but the data are currently limited due to small case numbers.

CONCLUSIONS

NOTES is most commonly performed using a hybrid, transvaginal approach. Although some aspects of these procedures appear to be well standardized, there is still significant variability in technique. More outcomes data with standardized reporting are needed to determine the actual risks and benefits of NOTES.

Natural orifice translumenal endoscopic surgery (NOTES(®)): a technical review

INTRODUCTION

The clinical NOTES literature continues to grow. This review quantifies the published human NOTES experience to date, examines instrument use in detail, and compiles available perioperative outcomes data.

METHODS

A PubMed search for all articles describing human NOTES cases was performed. All articles providing a technical description of procedures, excluding cases limited to diagnostic procedures, specimen extraction, fluid drainage or gynecological procedures, were reviewed. Two reviewers systematically cataloged the technical details of each procedure and performed a frequency analysis of instrument use in each type of case. Available outcomes data were also compiled.

RESULTS

Forty-three discrete articles were reviewed in detail, describing a total of 432 operations consisting of transvaginal (n = 355), transgastric (n = 58), transesophageal (n = 17), and transrectal (n = 2) procedures, with 90% of cases performed in hybrid fashion with laparoscopic assistance. Cholecystectomy (84% of cases) was the most common procedure. Analysis of key steps included choice of endoscope, establishment of peritoneal access, dissection, specimen extraction, and closure of the access site. Analysis of instrument use during transvaginal cholecystectomy revealed variation in the choice of endoscope and the technique for establishment of access. A majority of these procedures relied heavily on the use of rigid and transabdominal instrumentation. Closure of the vaginotomy site was found to be well standardized, performed with an open suturing technique. Similar analysis for transgastric procedures revealed consistency in the choice of flexible endoscope as well as access and closure techniques. Perioperative outcomes from NOTES procedures were reported, but the data are currently limited due to small case numbers.

CONCLUSIONS

NOTES is most commonly performed using a hybrid, transvaginal approach. Although some aspects of these procedures appear to be well standardized, there is still significant variability in technique. More outcomes data with standardized reporting are needed to determine the actual risks and benefits of NOTES.

Gastrotomy closure with the lock-it system and the Padlock-G clip: a survival study in a porcine model

BACKGROUND AND STUDY AIMS

The success of natural orifice surgery depends on secure closure of the transmural gut opening, so a rapid, secure, and easy-to-place closure method is desirable. Our aim was to determine whether a gastrotomy can be closed safely and effectively from within the stomach in a survival model by using a novel, endoscopically placed device: the Padlock-G system.

PATIENTS AND METHODS

This was a pilot study of 4 survival animals in an animal laboratory setting. Gastrotomies were made in the stomachs of laboratory swine, and the abdomen was explored by using a standard gastroscope. Gastrotomies were then closed by using the Padlock-G system. Survival for 2 or 6 weeks was the primary outcome measurement. Secondary outcomes included ease of use, visual assessment of closure integrity immediately and at necropsy, presence of adhesions, evidence of infection, and histologic appearance at the closure sites.

RESULTS

All animals thrived, ate normally, and gained weight. None developed fever, tachycardia, or signs of peritoneal irritation. Closure-site inspection at necropsy revealed excellent healing, with epithelial growth over the Padlock-G. There were no ulcers, serosal surfaces were tightly closed, and no defects could be seen. There were no signs of peritoneal inflammation, intra-abdominal adhesions, or gastric spillage. Histologic evaluation showed organizing granulation tissue with fibrosis, vascular proliferation, and mild chronic inflammatory infiltrate (i.e., scar).

CONCLUSIONS

The Padlock-G is easy to place, provides a durable closure, and allows survival animals to thrive without adverse sequellae. This device provides a suitable closure system for transgastric NOTES.

Endoscopic closure of GI fistulae by using an over-the-scope clip (with videos)

BACKGROUND

Preclinical studies have demonstrated the over-the-scope clip (OTSC) to be feasible and safe for closure of gastric, duodenal, and colonic perforations. A retrospective clinical study demonstrated the feasibility and preliminary safety of the OTSC for the treatment of GI bleeding and closure of acute GI perforations.

OBJECTIVE

Because the OTSC allows rapid and easy endoscopic organ wall closure, we hypothesized that it might be a useful tool to close GI fistulae.

DESIGN

Case series.

SETTING

Academic medical center.

PATIENTS

Four consecutive patients with GI fistulae.

INTERVENTIONS

In all patients, a 12-mm OTSC, in combination with the dedicated twin grasper, anchor device, or endoscopic suction, was used to facilitate endoscopic closure.

MAIN OUTCOME MEASUREMENTS

In 2 cases, OTSCs allowed complete closure of a posttraumatic esophagopulmonary fistula and a chronic gastrocutaneous fistula. Leak tests and follow-up examination demonstrated complete leakproof closures. In 1 esophagopulmonary fistula and 1 jejunocutaneous fistula, the initial closure attempts using OTSCs were not successful because of chronic fibrotic changes and scarring at the fistula site. Both OTSCs were removed by using an endoscopic grasping forceps. The mean procedure time was 54 minutes (range 24-93 minutes). There were no procedure-related complications.

LIMITATIONS

Small sample size.

CONCLUSIONS

The OTSC seems to be a feasible device to close chronic fistulae of the GI tract. It can achieve leakproof, full-thickness closure of transmural defects. Nevertheless, in circumstances of severe fibrosis and scarring, complete incorporation of the defect into the applicator cap and successful OTSC application might not be possible.

Feasibility of the transtracheal approach for the thoracic cavity in a large animal model

BACKGROUND

The aim of this study was to evaluate the performance of a novel transtracheal endoscopic technique for thoracic evaluation and intervention in a large animal model.

METHODS

In 12 animals (6 pigs and 6 dogs) under general anesthesia, a tracheal incision was made on the right lateral wall of the lower trachea and used as an entrance for thoracic evaluation and intervention. Postoperative follow-up included endoscopy at 1 and 2 weeks after surgery and necropsy at 2 weeks after surgery.

RESULTS

Transtracheal opening and thoracic exploration were achieved in all animals. Four animals (3 pigs and 1 dog) died as a result of complications from the procedure. At the follow-up endoscopy, healing at the tracheal opening region was noted in seven animals.

CONCLUSIONS

The transtracheal approach to the thoracic cavity is technically feasible in both porcine and canine models (4/12 animals died). The canine model is perhaps more suitable than the porcine model for the study of the transtracheal approach to the thoracic cavity.

Hydroperitoneum-facilitated EUS-guided peritoneal entry and closure of alternate access sites for NOTES

BACKGROUND

Access sites other than the anterior gastric wall may provide improved ergonomics for natural orifice transluminal endoscopic surgery (NOTES). Endoscopic ultrasound (EUS) guidance significantly reduces, but does not eliminate, risk of access through these alternate sites. This study evaluates the utility of hydroperitoneum as an adjunct to EUS-guided access and closure of alternate access sites for NOTES.

METHODS

Access and closure procedures were initially performed with EUS guidance alone, and subsequently, because of complications resulting from this technique, the procedures were performed with the aid of a transabdominal hydroperitoneum.

RESULTS

In this nonrandomized study, 6 access and closure procedures performed with EUS guidance alone resulted in 4 complications. After modifying the technique to incorporate pre-access hydroperitoneum, 7 EUS-guided access and closure procedures were performed without significant complications.

CONCLUSIONS

Hydroperitoneum appears to be an effective adjunct to ensure the safety of EUS-guided peritoneal entry and closure of alternate access sites for NOTES.

What are the elements of safe gastrotomy closure in NOTES? A systematic review

INTRODUCTION

The safe closure of the gastrotomy needs to be established before natural orifice translumenal endoscopic surgery (NOTES) can be extended to routine clinical practice. As yet no optimum closure method has been identified.

METHODS

A systematic review of the literature on gastrotomy closure modalities for NOTES up until December 2009 was undertaken. An assessment of each closure modality was determined using specified quantitative and qualitative parameters.

RESULTS

There were 46 studies included in this review describing 20 closure techniques. Some robustly designed experimental studies have now been published particularly in relation to the over-the-scope clip system.

CONCLUSION

Current evidence is experimental and therefore limited, but there appears to be some clarification in the direction of the innovative process in this area outlining favorable characteristics of an ideal system. Based on the studies examined in this review, a standardized assessment method is summarized for future in vivo studies, necessary prior to phase 1 trials.

Video. Natural orifice transtracheal evaluation of the thoracic cavity and mediastinum

BACKGROUND

This study aimed to determine the feasibility of a novel transtracheal endoscopic technique for thoracic and mediastinum evaluation in a canine model.

METHODS

In two dogs under general anesthesia, a transverse incision was made in the right lateral wall of the lower trachea and used as an entrance for thoracic and mediastinum evaluation.

RESULTS

Transtracheal thoracoscopic evaluation was possible in both animals. One animal experienced massive subcutaneous emphysema immediately after evaluation of the thoracic cavity and required chest tube drainage. The follow-up endoscopies 2 weeks after surgery showed good healing of the tracheal openings in both animals.

CONCLUSIONS

The transtracheal approach to the thoracic cavity and mediastinum appears to be feasible. This technique may provide an intriguing platform for the development of natural orifice transluminal surgery (NOTES) in the thoracic cavity.

Endoscopic full-thickness resection of gastric lesions using a novel grasp-and-snare technique: evaluation in a porcine survival model

BACKGROUND

Endoscopic full-thickness resection (EFTR) is a less-invasive method of en bloc removal of gastrointestinal tumors. In a previous nonsurvival animal experiment, the feasibility of a novel grasp-and-snare EFTR technique using a prototype tissue-lifting device was demonstrated. The objective of this study was to evaluate the safety and outcomes of this EFTR method in a porcine survival model.

METHODS

EFTR of model stomach tumors was performed in seven pigs using a double-channel endoscope with a prototype tissue-lifting device through one channel and snare through the other. The lifting device was advanced through the snare loop and anchored to the gastric wall adjacent the model tumor. The lifting device was then partially retracted into the endoscope, causing the target tissue, including tumor, to evert into the gastric lumen. The open snare was then placed beyond the tumor around uninvolved gastric tissue. Resection was performed by delivering an electrosurgical current through the snare. EFTR defects were closed by using tissue anchors. After an intended 10-day observation period, the pigs were euthanized and necropsy was performed.

RESULTS

All seven resections were successful with negative gross margins. No immediate complications occurred. Two defect closures failed during the early postoperative period, leading to infectious complications. The remaining intact closures were complicated by adjacent ulcers, one of which resulted in hemorrhage.

CONCLUSIONS

Endoscopic full-thickness resection of gastric lesions using the grasp-and-snare technique is feasible in pigs. In this experiment, complications related to closure were significant. Further evaluation and modification of closure technique is necessary before studying this method of EFTR in humans.