Natural orifice transluminal endoscopic surgery (NOTES) in the mediastinum: long-term survival animal experiments in transesophageal access, including minor surgical procedures

Transvaginal laparoscopic salpingo-oophorectomy: an oncological risk-reducing procedure

Aim:

Since the first natural orifice transluminal endoscopic surgery procedure, renewed interest has arisen in further developing and advancing minimal access surgery. We introduce a natural orifice endoscopic approach for a bilateral salpingo-oophorectomy.

Patients & methods:

Using the vagina as a natural orifice, we performed a transvaginal laparoscopic salpingo-oophorectomy to remove bilateral adnexa in patients with a strong family history of ovarian and/or breast cancer and those positive for BRCA1/2 mutation.

Results:

Total 36 women underwent transvaginal laparoscopic salpingo-oophorectomy. Conversion to routine laparoscopy was required in eight patients to complete the operation. No peri-operative complications were noted.

Conclusion:

We describe a novel approach in gynecological surgery. Our technique proved to be safe and efficient with the advantage of avoiding any abdominal scars.

This article describes a novel, keyhole surgical approach to remove tubes and ovaries in a female patient. The approach is known as a ‘natural orifice endoscopic approach’ and involves using the vagina as a natural orifice. Both tubes and ovaries were removed in patients with a strong family history of ovarian and/or breast cancer and those positive for BRCA1/2 genetic mutation. Two ports are inserted into the vagina to access the abdomen with both specimens subsequently retrieved vaginally. Total 36 women underwent the procedure with no complications. The technique proved to be safe and efficient with the advantage of avoiding any abdominal scars compared with routine keyhole surgery.

Updated Systematic Review of Achalasia, with a Focus on POEM Therapy

AIM

To systematically review clinical presentation, diagnosis, and therapy of achalasia, focusing on recent developments in high-resolution esophageal manometry (HREM) for diagnosis and peroral endoscopic myotomy (POEM) for therapy.

METHODS

Systematic review of achalasia using computerized literature search via PubMed and Ovid of articles published since 2005 with keywords ("achalasia") AND ("high resolution" or "HREM" or "peroral endoscopic myotomy" or "POEM"). Two authors independently performed literature searches and incorporated articles into this review by consensus according to prospectively determined criteria.

RESULTS

Achalasia is an uncommon esophageal motility disorder, usually manifested by dysphagia to solids and liquids, and sometimes manifested by chest pain, regurgitation, and weight loss. Symptoms often suggest more common disorders, such as gastroesophageal reflux disease (GERD), thus often delaying diagnosis. Achalasia is a predominantly idiopathic chronic disease. Diagnosis is typically suggested by barium swallow showing esophageal dilation; absent distal esophageal peristalsis; smoothly tapered narrowing ("bird's beak") at esophagogastric junction; and delayed passage of contrast into stomach. Diagnostic findings at high-resolution esophageal manometry (HREM) include: distal esophageal aperistalsis and integrated relaxation pressure (trough LES pressure during 4 s) > 15 mmHg. Achalasia is classified by HREM into: type 1 classic; type 2 compartmentalized high pressure in esophageal body, and type 3 spastic. This classification impacts therapeutic decisions. Esophagogastroduodenoscopy is required before therapy to assess esophagus and esophagogastric junction and to exclude distal esophageal malignancy. POEM is a revolutionizing achalasia therapy. POEM creates a myotomy via interventional endoscopy. Numerous studies demonstrate that POEM produces comparable, if not superior, results compared to standard laparoscopic Heller myotomy (LHM), as determined by LES pressure, dysphagia frequency, Eckardt score, hospital length of stay, therapy durability, and incidence of GERD. Other therapies, including botulinum toxin injection and pneumatic dilation, have moderately less efficacy and much less durability than POEM.

CONCLUSION

This comprehensive review suggests that POEM is equivalent or perhaps superior to LHM for achalasia in terms of cost efficiency, hospital length of stay, and relief of dysphagia, with comparable side effects. The data are, however, not conclusive due to sparse long-term follow-up and lack of randomized comparative clinical trials. POEM therapy is currently limited by a shortage of trained endoscopists.

Submucosal tunnel endoscopic resection for extraluminal tumors: a novel endoscopic method for en bloc resection of predominant extraluminal growing subepithelial tumors or extra-gastrointestinal tumors (with videos)

BACKGROUND AND AIMS

The management of subepithelial tumors with a predominant extraluminal growth pattern or extra-GI tumors can be challenging and traditionally requires a surgical resection that is not only invasive but may carry a significant risk of morbidity and mortality. We aimed to assess the feasibility, safety, and efficacy of a novel endoscopic technique termed submucosal tunnel endoscopic resection for extraluminal tumors (STER-ET).

METHODS

We prospectively enrolled patients who underwent STER-ET for GI subepithelial tumors with a predominant extraluminal growth pattern or extra-GI tumors located at the level of cardia or the proximal part of the lesser curvature of the stomach seen on cross-sectional imaging between January 2016 and March 2017.

RESULTS

Eight patients underwent STER-ET. The mean (± standard deviation) tumor size was 2.8 ± 0.6 cm and 2.3 ± 0.8 cm in longest and shortest dimension, respectively. The average procedure time was 67 ± 4.4 minutes. The rates of curative en bloc resection and en bloc retrieval was 100% and 87.5%, respectively. On final histology, 6 tumors were GI stromal tumors, 1 was a schwannoma, and 1 was a foregut cyst. Five patients had capnoperitoneum during the procedure and required abdominal decompression. One patient had a small mucosotomy successfully treated with a hemostatic clip. There were no major adverse events or deaths. The median length of hospital stay was 3 days. There was no residual tumor on surveillance imaging after a mean follow-up period of 10.0 ± 2.1 months.

CONCLUSIONS

STER-ET is a novel technique that appears to be safe and effective in achieving a curative resection for GI subepithelial tumors with a predominantly extraluminal growth pattern or extraluminal tumors in a selected group of patients. However, larger studies are required to validate our finding.

Adverse events of NOTES mediastinoscopy compared to conventional video-assisted mediastinoscopy: a randomized survival study in a porcine model

BACKGROUND

Safety is a concern in natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy. The objective of this study was to compare the safety of NOTES mediastinoscopy with video-assisted mediastinoscopy (VAM).

METHODS

Twenty-four pigs were randomly assigned to NOTES or VAM. Thirty-minute mediastinoscopies were performed with the identification of seven predetermined structures. The animals were euthanized after 7 days and necropsy was performed.

RESULTS

Mediastinoscopy was not possible in one animal in each group. There were more intraoperative adverse events with NOTES than VAM (7 vs. 2, P = 0.04); hemorrhage was the most frequent adverse event (4 and 1, respectively). At necropsy, pathological findings were observed in 13 animals (9 NOTES and 4 VAM; P = 0.03). Inflammatory parameters were not different between groups and were not related to adverse events.

CONCLUSION

Systematic NOTES mediastinoscopy is possible and comparable to VAM in terms of number of organs identified and inflammatory impact. However, the safety profile of NOTES mediastinoscopy has to be improved before it can be adopted in a clinical setting.

Recent advances in natural orifice transluminal endoscopic surgery†

Natural orifice transluminal endoscopic surgery (NOTES) has emerged as one of the most exciting areas in the field of minimally invasive surgery during the last decade. NOTES comprises a wide spectrum of procedures from various natural accesses such as transgastric or transvaginal routes, and different direct-target or distant-target organs. Since polypectomy was first performed in 1955, major advances in technology and refinement of endoscopic technique have allowed endoscopic surgeons to perform complex endoscopic interventions such as endoscopic submucosal dissection. Recognizing the safety and feasibility of submucosal tunnelling and mucosal closure, endoscopic resection beyond the level of mucosa has been increasingly reported. One of these procedures, peroral endoscopic myotomy for achalasia, has gained much popularity and excellent results have been published comparable with that of traditional Heller's cardiomyotomy. Submucosal tunnelling endoscopic resection has also been reported for tumours situated in the muscular layer of the gastrointestinal tract. To overcome the difficulty of intestinal closure after NOTES, researchers have collaborated with the industry in developing different endoscopic suturing devices such as the Eagle Claw (Olympus Medical Systems, Tokyo, Japan) and Overstitch™ (Apollo Endosurgery, Austin TX, USA). These devices allow precise and secure suture application with the ordinary flexible endoscope, achieving tissue approximation similar to open surgical suturing. To further expand the potential of NOTES, investigators had also developed multitasking platforms enabling the performance of surgical procedures of even higher complexity. Recently, a novel endoscopic robotic system 'Master and Slave Transluminal Endoscopic Robot' (MASTER) has been developed. Early results of endoscopic resection utilizing this system have been encouraging, allowing both experts and novices in endoscopy to perform difficult endoscopic resection with a high degree of flexibility.

Natural-orifice translumenal endoscopic surgery (NOTES): minimally invasive evolution or revolution?

Since the first animal experimental laparoscopy in 1902, minimal access techniques have revolutionized surgery. Using the natural orifice dates back to at least the second century when Soranus performed a vaginal hysterectomy. The main difference between traditional endolumenal surgery and the translumenal approach of natural-orifice translumenal endoscopic surgery (NOTES) is the intentional puncture of a healthy organ in NOTES to access a cavity or other organ. The aim of this review was to examine the past, present, and potential future role of NOTES in the context of other developments in minimal access surgery. NOTES is at an early stage in its development and a convincing benefit over laparoscopy has not been demonstrated. Concerns regarding complications, for example of viscerotomy closure, have limited the widespread uptake of pure NOTES. However, it is likely that technological advances for NOTES surgery will enhance conventional laparoscopic and endoscopic techniques.

A novel approach to treat women patients with palmar hyperhidrosis: transumbilical thoracic sympathectomy with an ultrathin gastroscope

BACKGROUND

Primary palmar hyperhidrosis is very common in women. Video-assisted thoracic sympathectomy is recognized as an effective treatment for patients with severe hyperhidrosis, which has usually been performed with more than 2 skin incisions. We developed a novel approach for thoracic sympathectomy in women with palmar hyperhidrosis through the umbilicus using an ultrathin gastroscope. The approach requires only 1 tiny incision, which is hidden in the umbilicus.

METHODS

Under general anesthesia, patients were intubated with a dual-lumen endotracheal tube. Through the incision in the umbilicus, a newly developed long trocar was inserted into the abdominal cavity. After insertion of the ultrathin gastroscope through this trocar, a small incision was created on the both sides of diaphragm by a needle knife. The endoscope was introduced into the thoracic cavity through the incision made in the left or right diaphragm. The sympathetic chain was identified at the desired thoracic level and ablated.

RESULTS

From January 10, 2010, to November 30, 2011, 25 women underwent transumbilical-diaphragmatic thoracic sympathectomy. The mean operating room time for the entire bilateral procedure was 56.9 ± 6.9 minutes. There were no significant postoperative complications. The symptoms disappeared in all patients. Compensatory sweating was reported in 56%. All of the patients were satisfied with the surgical results and the cosmetic outcome of the incision.

CONCLUSIONS

Transumbilical thoracic sympathectomy with the ultrathin flexible endoscope was a safe and effective option for women with severe palmar hyperhidrosis that provided excellent cosmetic outcomes.

Is the transvaginal route appropriate for intra-abdominal NOTES procedures? Experience and follow-up of 222 cases

BACKGROUND

Since 2007, natural orifice transluminal endoscopic surgery (NOTES) has been applied in humans. We performed this prospective study to evaluate the transvaginal route in terms of risks, complication rate, and long-term side effects such as dyspareunia.

METHODS

From June 2007 to September 2011, we performed 222 transvaginal hybrid NOTES procedures: 220 transvaginal cholecystectomies (TVC) and 2 transvaginal appendectomies (TVA). All patients were asked to present to our associated gynecologists within 1 week for an examination. After at least 3 months, the patients were interviewed using a standard questionnaire.

RESULTS

All operations could be successfully performed in this technique except two cases, which were converted to conventional laparoscopic cholecystectomy. The only intraoperative complication was the puncture of the urine bladder. We observed two postoperative complications: one biliary fistula 3 days after TVC, and one abscess in the Douglas pouch 3 weeks after TVC. The gynecological examinations revealed no abnormalities. The interview (median postoperative time, 6 months) with a follow-up rate of 93 % revealed no pain in the pelvis, dyspareunia, or sexual dysfunction after TVC.

CONCLUSIONS

The transvaginal route is appropriate for NOTES procedures; there is only a minor and acceptable rate of intra- and postoperative morbidity.

Comparative study of NOTES alone versus NOTES guided by a new image registration system for navigation in the mediastinum: a study in a porcine model

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy (MED) through the esophagus has proved to be feasible in the animal model. However, injury of the adjacent pleura and pneumothorax has been reported as a frequent adverse event when using a blind access.

OBJECTIVE

To assess the utility and safety of a CT-based image registration system (IRS) for navigation in the mediastinum.

DESIGN

Prospective, randomized, controlled trial in 30 Yorkshire pigs. Thirty-minute MEDs were performed: 15 MEDs were performed with IRS guidance (MED-IRS), and 15 MEDs were performed with a blind access.

SETTING

Animal research laboratory.

INTERVENTIONS

In both groups, the mediastinum was accessed through a 10-cm submucosal tunnel in the esophageal wall. Timed exploration was performed with identification of 8 mediastinal structures.

MAIN OUTCOME MEASUREMENTS

Technical feasibility, adverse events, and the number of mediastinal structures identified.

RESULTS

Thirty animals weighing 31.5 ± 3.5 kg were included in this study. MED was not possible in 2 animals in the "MED with blind access" group but was possible in all MEDs performed with IRS. The mean number of identified organs was slightly higher in "with IRS-MED" (6.13 ± 1.3) than with MED with blind access (4.7 ± 2.3; P = .066). Moreover, the right atrium and vena cava were identified in more cases with IRS-MED than in MED with blind access (13 vs 3 and 15 vs 11, P = .000 and P = .03, respectively). There were 3 (23%) adverse events with IRS-MED and 4 (27%) with "MED with blind access" (P = not significant), with pneumothorax being the most frequent (2 and 3, respectively).

LIMITATIONS

Nonsurvival animal study.

CONCLUSIONS

This study demonstrates that the IRS system appears feasible in natural orifice transluminal endoscopic surgery MED and suggests that IRS guidance might be useful for selected procedures.

The effectiveness of rigid pericardial endoscopy for minimally invasive minor surgeries: cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation

Background

The efficacy and safety of rigid pericardial endoscopy as the promising minimally invasive approach to the pericardial space was evaluated. Techniques for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were developed.

Methods

Two swine and 5 canines were studied to evaluate the safety and efficacy of rigid pericardial endoscopy. After a double pericardiocentesis, a transurethral rigid endoscope was inserted into the pericardial space. The technique to obtain a clear visual field was examined, and acute complications such as hemodynamic changes and the effects on intra-pericardial pressure were evaluated. Using custom-made needles, pacemaker leads, and forceps, the applications for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were also evaluated.

Results

The use of air, the detention of a stiff guide wire in the pericardial space, and the stretching of the pericardium with the rigid endoscope were all useful to obtain a clear visual field. A side-lying position also aided observation of the posterior side of the heart. As a cell transplantation methodology, we developed an ultrasonography-guided needle, which allows for the safe visualization of transplantation without major complications. Pacemaker leads were safely and properly implanted, which provides a better outcome for cardiac resynchronizing therapy. Furthermore, the success of clear visualization of the pulmonary veins enabled us to perform epicardial ablation.

Conclusions

Rigid pericardial endoscopy holds promise as a safe method for minimally invasive cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation by allowing clear visualization of the pericardial space.

Natural orifice translumenal endoscopic surgery for anterior spinal procedures

Background. NOTES techniques allow transesophageal access to the mediastinum. The aim of this study was to assess the feasibility of transesophageal biopsy of thoracic vertebrae. Methods. Nonsurvival experiments on four 50-kg porcine animals were performed. Transesophageal access to the mediastinum was attained using submucosal tunneling technique. Results. The posterior mediastinum was successfully accessed and navigated in all animals. Vertebral bodies and intervertebral spaces were easily approached while avoiding damage to adjacent vessels. Bone biopsy was successfully performed without complications, but the hardness of bone tissue resulted in small and fragmented samples. Conclusions. Peroral transesophageal access into the posterior mediastinum and thoracic vertebral bone biopsy was feasible and safe. The proximity of the esophagus to the vertebral column provides close and direct access to the thoracic spine and opens up new ground for the performance of multilevel anterior spine procedures using NOTES techniques.

Left atrial appendage ligation with single transthoracic port assistance: a study of survival assessment in a porcine model (with videos)

BACKGROUND

Left atrial appendage (LAA) exclusion is a well-known procedure for the prevention of stroke in high-risk patients with atrial fibrillation and contraindication to long-term oral anticoagulant therapy.

OBJECTIVE

To evaluate a natural orifice transluminal endoscopic surgery (NOTES) approach for LAA ligation.

DESIGN

In 4 acute and 6 survival pigs, we performed LAA by using a forward-viewing, single-channel gastroscope and an operative thoracoscope with a 3-mm working channel (introduced through an 8-mm single transthoracic port).

SETTING

Animal laboratory.

INTERVENTIONS

The gastroscope was introduced in the thoracic cavity through an esophageal submucosal tunnel. An end loop introduced through the gastroscope was used to legate the LAA. In the survival experiments, the esophageal mucosa was closed using hemoclips.

MAIN OUTCOME MEASUREMENTS

The time, safety, and feasibility of the procedure were recorded. In the survival experiments, endoscopy and postmortem examination were performed on postoperative day 14.

RESULTS

Creation of a submucosal tunnel and esophagotomy were safely performed in all animals without incidents. The mean time for esophagotomy was 17.0 ± 6.3 minutes. Pericardial dissection and LAA ligation were performed in all animals but 1. The mean time for LAA ligation was 34.4 ± 19.1 minutes. No adverse events occurred during the survival period. Endoscopy showed complete esophageal closure. Postmortem examination revealed pleural adhesions on the site of pericardial dissection, and the LAA was fibrotic with the endoloop in place.

LIMITATIONS

Animal study.

CONCLUSIONS

LAA ligation with single transthoracic trocar assistance is feasible and may be an alternative to anticoagulant therapy or to permanent intracardiac implants in patients with atrial fibrillation.

Natural orifice transesophageal endoscopic surgery: state of the art

The main goal of Natural Orifice Transluminal Endoscopic Surgery (NOTES) is performing surgery avoiding skin incisions. Theoretical advantages of NOTES include decreased postoperative pain, reduction/elimination of general anesthesia, improved cosmetic outcomes, elimination of skin incision-related complications such as wound infections and hernias, and increased overall patient satisfaction. Although various forms of port creation to accomplish thoracic NOTES procedures have been proposed, transesophageal NOTES has been shown to be the most reliable one. The evolution of endoscopic submucosal transesophageal access resulted in the development of per-oral endoscopic myotomy (POEM), which had a fast transition to clinical practice. The authors present a review of the current state of the art concerning transesophageal NOTES, looking at its potential for diagnostic and therapeutic interventions as well as the hurdles yet to be overcome.

A novel approach for the treatment of pelvic abscess: transrectal endoscopic drainage facilitated by transanal endoscopic microsurgery access

BACKGROUND

Postoperative pelvic abscesses in patients submitted to colorectal surgery are challenging. The surgical approach may be too risky, and image-guided drainage often is difficult due to the complex anatomy of the pelvis. This article describes novel access for drainage of a pelvic collection using a minimally invasive natural orifice approach.

METHODS

A 37 year-old man presented with sepsis due to a pelvic abscess during the second postoperative week after a Hartmann procedure due to perforated rectal cancer. Percutaneous drainage was determined by computed tomography to be unsuccessful, and another operation was considered to be hazardous. Because the pelvic fluid was very close to the rectal stump, transrectal drainage was planned. The rectal stump was opened using transanal endoscopic microsurgery (TEM) instruments. The endoscope was advanced through the TEM working channel and the rectal stump opening, accessing the abdominal cavity and pelvic collection.

RESULTS

The pelvic collection was endoscopically drained and the local cavity washed with saline through the scope channel. A Foley catheter was placed in the rectal stump. The patient's recovery after the procedure was successful, without the need for further intervention.

CONCLUSIONS

Transrectal endoscopic drainage may be an option for selected cases of pelvic fluid collection in patients submitted to Hartmann's procedure. The technique allows not only fluid drainage but also visualization of the local cavity, cleavage of multiloculated abscesses, and saline irrigation if necessary. The use of TEM instrumentation allows safe access to the peritoneal cavity.

Endoscopic closure of a tracheal access site using bioglue after transtracheal thoracoscopy in a nonsurvival canine model

OBJECTIVES

An ideal wound closure device would repair the wound with minimal complexity. In this report, we describe a simple wound closure method using BioGlue sealant.

METHOD

Eleven canines underwent transtracheal pericardial window creation under endoscopic guidance for natural orifice transluminal endoscopic surgery (NOTES). The tracheal wound was closed using BioGlue sealant. The integrity of the wound was assessed by determining the amount of air leaking under mechanical ventilation.

RESULTS

Transtracheal thoracic exploration and pericardial window creation was successful for all of the canines, and adequate wound closure was achieved in 10 of the canines. There was 1 case of NOTES-related death arising from misplacement of the endotracheal tube in the left lower lobar bronchus. This caused a collapse of the left upper lobe and ventilatory failure. Minor lung injuries occurred in 3 canines and minor mediastinal bleeding was encountered in 1 canine during the creation of the access site.

CONCLUSION

BioGlue sealant was found to be effective in sealing the tracheal wound in all but 1 of the canines. This study demonstrates that the use of the sealant is a simple and efficient means of endoscopically closing the tracheal access site in NOTES.

Interventional endoscopy and single incision surgery

The following on interventional endoscopy and single incision surgery contains commentaries on transluminal endoscopic esophageal surgery, flexible endoscopy, triangulation, advanced flexible operating platforms, experimental transesophageal procedures, and para- and intra-esophageal endoscopic surgery.

New methods for innovation: the development of a toolbox for natural orifice translumenal endoscopic surgery (NOTES) procedures

BACKGROUND

Devices used for flexible intralumenal procedures are inadequate when used for intraperitoneal surgical procedures such as cholecystectomy.

OBJECTIVE

To assess/address limitations of flexible endoscopic devices in intraperitoneal surgery.

DESIGN

To describe processes used to invent new devices to facilitate this new surgical genre.

SETTING

Engineering laboratory.

PATIENTS

None. INTERVENTIONS AND INVENTIONS: Reviews of the limitations of flexible endoscopic instruments and instrumentation/invention needs for a "NOTES cholecystectomy" were completed.

MAIN OUTCOME MEASURES

The appropriateness of existing methods of device innovation was evaluated against an inventory of new technologies necessary to perform NOTES. The deficiencies in traditional innovation methods led to the creation of a novel process for invention of new medical devices: the "Inventorama."

METHODS

Cooperation between clinicians and industry to develop device concepts to enable NOTES.

RESULTS

The devices included: (1) steerable flex trocar, (2) rotary access needle, (3) bipolar hemostasis forceps, (4) Maryland dissectors, (5) articulating hook knife, (6) rotating hook knife, (7) articulating graspers, (8) scissors, (9) ligating clip applier, and (10) tissue apposition system. Six of these ten were built and tested as initial crude prototypes in the Inventorama process; two underwent major modifications. Three were invented via alternate methods, including by independent clinicians.

CONCLUSIONS

A new method for efficient medical device invention and development was created to address key technology needs for NOTES. The result was a "toolbox" of devices designed to address the key surgical activities necessary for advanced intralumenal and translumenal flexible endoscopic procedures.

Feasibility of Endoscopic Transoral Surgical Lung Biopsy in a Live Canine Model

Background. The feasibility of using a transoral approach to the thoracic cavity has not yet been measured in humans or animals. The present study aimed to evaluate the feasibility of transoral surgical lung biopsy (TOLB) in 10 canines. Methods. Through an incision over the vestibulum oris, a homemade metal tube was introduced into the thoracic cavity under endoscopic guidance and used as a working channel of surgical lung biopsy. TOLB was performed on the predetermined lung lobe by using an electrocautery loop and endoscopic grasper. Results. Successful surgical lung biopsy was achieved in 8 of 10 animals in a mean time of 132 minutes (range 130-190 minutes). There were no major intraoperative or postoperative complications, and all animals survived for 2 weeks after surgery. Autopsy showed no evidence of vital structure injury, mediastinitis, or empyema. Conclusions. TOLB was demonstrated to be safe and feasible in a canine model.

Natural orifice transluminal endoscopy surgery: A review

Minimally invasive surgery started spreading worldwide in 1987, when the first laparoscopic cholecystectomy was performed. Meanwhile, improvement of endoscopic equipment and instruments allowed gastroenterologists to attempt more aggressive endoluminal interventions, even beyond the wall barrier. The first transgastric peritoneoscopy, in 2004, brought to light the concept of natural orifice transluminal endoscopic surgery (NOTES). The idea of incisionless surgery is attractive and has become a new goal for both surgeons and other people interested in this field of investigation. The authors present a review of all developments concerning NOTES, including animal studies and human experience.

Critical analysis of hot topics in NOTES

Natural orifice transluminal endoscopic surgery (NOTES) has gained a great deal of attention from gastroenterologists and surgeons all over the world since its introduction in 2000. The field of NOTES has advanced tremendously since that time and exciting and well-designed research has been reported. Both randomized controlled trials and results from large national and international registries have been published. Many experimental and clinical studies have discussed transesophageal, transgastric, transvaginal and transrectal access for a variety of NOTES procedures. Transvaginal access has been the most frequently reported NOTES access route in clinical trials. When suitable instruments become available, a true comparison of NOTES with current laparoscopic approaches can be realized.

A prospective, randomized trial of esophageal submucosal tunnel closure with a stent versus no closure to secure a transesophageal natural orifice transluminal endoscopic surgery access site

BACKGROUND

Secure esophagotomy closure methods are a critical element in the advancement of transesophageal natural orifice transluminal endoscopic surgery (NOTES) procedures.

OBJECTIVE

To compare the clinical outcomes in swine receiving an esophageal stent or no stent after a submucosal tunnel NOTES access procedure.

DESIGN

Prospective, randomized, controlled trial in 10 Yorkshire swine.

SETTING

Academic center.

INTERVENTION

An endoscopic mucosectomy device was used to create an esophageal mucosal defect. An endoscope was advanced through a submucosal tunnel into the mediastinum and thorax, and diagnostic mediastinoscopy and thoracoscopy were performed. Ten animals were randomized to no stenting (n = 5) or stenting (n = 5) with a prototype small-intestine submucosa-covered stent.

MAIN OUTCOME MEASUREMENTS

Gross and histologic appearance of the mucosectomy and esophagotomy sites as well as clinical outcomes.

RESULTS

There was a significant difference in the overall procedure time between the animals that received a stent (35.0 min, range 27-46.0 min) and those with no closure (19.0 min, range 17-32 min) (P value = .018). The unstented group achieved endoscopic and histologic evidence of complete re-epithelialization and healing (100%) at the mucosectomy site compared with the stented group (20%, P = .048). Stent migration into the stomach occurred in two swine. Both groups had complete closure of the submucosal tunnel and well-healed esophagotomy sites.

LIMITATIONS

Animal study, small number of subjects.

CONCLUSION

The placement of a covered esophageal stent significantly interferes with mucosectomy site healing.

Transesophageal NOTES--a critical analysis of relevant problems

The transesophageal access route has not become a principal topic in the discussion about NOTES up to now. Analyzing the problems in this new field of surgery, however, the transesophageal route shows high relevance. Here, all possibilities, limitations, and problems of NOTES become obvious. This paper contains a critical analysis of the literature published to date (nine full papers, five abstracts). Nearly all publications represent experimental studies in living pigs. In most cases a submucosal tunnel technique is performed as access route to mediastinum, pleural cavity, and heart. Interventions and operations include simple mediastinoscopies as well as epicardial operations after exposition of the heart. For access and manipulation, conventional flexible endoscopes and instruments are used. Clips, T-bars, or a combination of both achieve the closure. Some studies rely on spontaneous closure of the incision without any suturing or approximation. In such experimental settings, the following results are presented: Access is achieved in 90% of cases, the aim of the operation is met in 92%, technical success in closure is achieved in 90%, healing of incision assessed as good in two of five studies, satisfactory in three of five studies. Mortality, ranging from 6 to 25%, and complication rates were (surprisingly) high. It has to be stressed that analyzing these papers published to date, no adequate attention is paid to basic facts and problems of general and thoracic surgery (e.g. different forms, prevention, diagnosis and therapy of pneumothorax or differentiated forms of ventilation). Relevant differences in the anatomy and physiology of the esophagus and mediastinum between humans and pigs should additionally be taken into account to choose optimal experimental parameters when transferring results to human settings. Moreover, requirements regarding sterility and hygiene in a structure like the mediastinum, which is at high risk from the point of view of infection biology, have not yet been respected. These factors should be taken into account in further studies--as well as clinically relevant disease patterns in humans--to be able to realize possible advantages of this NOTES access in a clinical setting.

NOTES cholecystectomy: matched-pair analysis comparing the transvaginal hybrid and conventional laparoscopic techniques in a series of 216 patients

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) is currently a very important topic for both gastroenterologists and surgeons. We have developed a technique of transvaginal hybrid NOTES cholecystectomy (TVC) that leaves no visible scar and is applicable to daily use. This technique is compared to the conventional laparoscopic cholecystectomy (CLC) in a matched-pair analysis.

METHODS

From June 2007 until February 2009, 108 NOTES cholecystectomies were performed. For a matched-pair analysis we first selected a group of 192 female patients who had undergone CLC and who were operated on by the same group of surgeons in the same time period. Then 108 pairs who had TVC were matched according to the degree of inflammation of the gallbladder and age. We were able to contact 208 patients at least 3 months after surgery. Hence, the study analysis was performed with 100 complete pairs.

RESULTS

All 200 cholecystectomies were performed successfully without conversion. The TVC procedure was significantly longer than CLC (52 vs. 35 min, p<0.001). There were no intraoperative complications in either group. There were no significant differences with respect to reoperations, wound infections, consumption of analgesic drugs, length of hospital stay, and sick leave. Seventy-five TVC and 73 CLC patients had sexual intercourse after the operation without any complaints.

CONCLUSION

We present here the largest series of NOTES for cholecystectomy published to date and the first comparative study with the gold standard. The TVC technique is as successful as the CLC, it causes no more complications than CLC, especially with respect to the vaginal approach, it is more time-consuming to perform, but has an ideal cosmetic result, i.e., no visible scar.

Feasibility and safety of endoscopic transesophageal access and closure using a Maryland dissector and a self-expanding metal stent

BACKGROUND

Secure access and reliable closure is paramount in the setting of transesophageal mediastinal endoscopic surgery. The purpose of this study was to develop a secure transesophageal access technique and to evaluate the feasibility, safety, and efficacy of a novel covered, self-expanding, retractable stent for closure of 15-mm esophageal defects.

METHODS

Fifteen-millimeter esophagotomies were created in 18 domestic pigs using needle knife puncture and balloon dilatation or a blunt dissection technique. Six animals were randomly assigned to open surgical repair and six animals to endoscopic closure using a self-expanding, covered, nitinol stent (Danis SX-ELLA stent, ELLA-CS) in a nonsurvival setting. Pressurized leak tests were performed on all closures. Six animals underwent transesophageal endoscopic mediastinal interventions and survived for 17 days. Stents were extracted at day 10.

RESULTS

Nonsurvival experiments revealed two bleeding complications associated with the needle-knife access technique, while blunt-dissection mediastinal access was not associated with any complications. Leak test results were not different for stent compared to surgical closures. All survival animals were found to have complete closure and adequate healing of the esophagotomies. No leakage or infectious complication occurred.

CONCLUSION

Blunt dissection achieves safe access into the mediastinum. Stent closure achieves similar leak test results compared to surgical closure and results in adequate sealing and wound healing of 15-mm esophageal defects.

Transcervical heller myotomy using flexible endoscopy

INTRODUCTION

Esophageal achalasia is most commonly treated by laparoscopic myotomy. Transesophageal approaches using flexible endoscopy have recently been described. We hypothesized that using techniques and flexible instruments from our NOTES experience through a small cervical incision would be a safer and less traumatic route for esophageal myotomy. The purpose of this study was to evaluate the feasibility, safety, and success rate of using flexible endoscopes to perform anterior or posterior Heller myotomy via a transcervical approach.

METHODS

This animal (porcine) and human cadaver study was conducted at the Legacy Research and Technology Center. Mediastinal operations on ten live, anesthetized pigs and two human cadavers were performed using standard flexible endoscopes through a small incision at the supra-sternal notch. The esophagus was dissected to the phreno-esophageal junction using balloon dilatation in the peri-esophageal space followed by either anterior or posterior distal esophageal myotomy. Success rate was recorded of esophageal dissection to the diaphragm and proximal stomach, anterior and posterior myotomy, perforation, and complication rates.

RESULTS

Dissection of the esophagus to the diaphragm and performing esophageal myotomy was achieved in 100% of attempts. Posterior Heller myotomy was always extendable onto the gastric wall, while anterior gastric extension of the myotomy was found to be more difficult (4/4 and 2/8, respectively; P = 0.061).

CONCLUSION

Heller myotomy through a small cervical incision using flexible endoscopes is feasible. A complete Heller myotomy was performed with a higher success rate posteriorly possibly due to less anatomic interference.

Clip closure versus endoscopic suturing versus thoracoscopic repair of an iatrogenic esophageal perforation: a randomized, comparative, long-term survival study in a porcine model (with videos)

BACKGROUND

Esophageal full-thickness wall repair is an important but unsolved issue in endoscopy. It is unknown how well endoscopic clip closure (ECC) and endoscopic closure with suturing (ECS) perform compared with the criterion standard of thoracoscopic closure (TC).

OBJECTIVE

Comparison of technical success, feasibility, long-term patency, complications, and histological quality of the different closure techniques (ECC, ECS, TC) for esophageal perforations.

DESIGN

Comparative animal study.

SETTING

Approved animal facility.

SUBJECTS

Eighteen pigs.

INTERVENTIONS

Eighteen pigs were randomized, 6 each into 3 groups (ECC, ECS, TC). After endoscopic wall incision and mediastinoscopy, closure was performed by using 1 of the 3 techniques. After 8 to 12 weeks, pre-euthanasia endoscopic, necropsy, histological, and morphometric analyses were performed.

MAIN OUTCOME MEASUREMENT

Long-term survival and histological quality of the repair.

RESULTS

The closure of the esophageal incisions was successful in all pigs. On days 2 and 6, 1 animal died of mediastinitis, 1 in the ECS group because of reflux of gastric contents into the mediastinum before the repair and 1 in the TC group because of leakage of the sutured closure (P = 1.0). No strictures were seen on prenecropsy endoscopy. At necropsy, 1 mediastinal abscess was found in an ECS animal (P = 1.0). Minor complications included periesophageal adhesions and reactive lymph nodes in 3 of 6 (ECC group) and 5 of 6 (TC and ECS groups). Histology showed muscle layer defects up to 12 mm in width and 21 mm in length, with a trend toward smaller defect size of width and length in the ECS group of animals.

LIMITATIONS

Animal study of limited size.

CONCLUSIONS

Overall, ECS and ECC performed similarly to TC. ECS showed the smallest histological defects in the long-term repair.

Development of a new trans-oral endoscopic approach for mediastinal surgery based on 'natural orifice surgery': preclinical studies on surgical technique, feasibility, and safety

OBJECTIVE

In recent years, several surgical disciplines adopted endoscopic techniques. Presently, natural orifice approaches are under exploration to reduce surgical access trauma. We have developed a trans-oral endoscopic approach for endoscopic mediastinal surgery and have tested this new technique in preclinical studies for feasibility and safety.

METHODS

We conducted an experimental anatomical study in fresh-frozen cadavers. By a midline, sublingual incision, we placed an optical scissor through a 6.0-mm trocar in the pretracheal region and created a working space; two additional trocars were placed by bi-vestibular incisions in the oral cavity. We visualized and followed the trachea down to the main bronchi. Paratracheal and subcarinal lymph nodes were resected bilaterally; the specimen could be removed through the midline channel. In an additional animal study in pigs, we tested the feasibility and safety for this surgical approach. Anatomical dissection allowed an estimate of collateral damage.

RESULTS

In all cases, we could reach the target region endoscopically, and no conversion was necessary. Landmarks (the brachiocervical trunk, the azygos vein, and the pulmonary artery) were visualized easily and kept intact. A working space in the mediastinum could be established by the insufflation of air at 6-8mmHg. It was possible to harvest the specimen through the midline channel. Anatomical dissection of the cervical access route as well as of the mediastinal region showed no collateral damage. In the animal study, we encountered seroma of the surgical field due to the conditions of the animal model. The other outcomes with respect to pain and food intake were normal until the third postoperative day. No local infections occurred. Intraoperative gas exchange was normal and was not influenced by CO(2) insufflation with respect to blood gas analysis.

CONCLUSION

These preclinical studies showed that the mediastinum could be reached by a trans-oral endoscopic approach, based on natural orifice surgery. Complete compartment resection of the paratracheal and subcarinal lymph node stations was possible in a well-defined and clearly visible working space. This approach may enhance the extent of mediastinal resections in oncologic surgery.

Endoscopic transesophageal mediastinal lymph node dissection and en bloc resection by using mediastinal and thoracic approaches (with video)

BACKGROUND

The criterion standard for sampling mediastinal lymph nodes is cervical mediastinoscopy. Current methods that require transthoracic or cervical incisions can result in significant postoperative pain.

OBJECTIVE

To determine the feasibility of a novel, transesophageal endoscopic technique for mediastinal lymph node dissection and en bloc resection.

DESIGN

Nonsurvival and survival animal study.

SETTING

Animal trial at a tertiary-care academic center.

SUBJECTS

This study involved 12 Yorkshire swine.

INTERVENTION

An endoscopic cap band mucosectomy device was used to create an esophageal mucosal defect. By using the tip of the endoscope and biopsy forceps, a submucosal tunnel was fashioned, and, within the submucosal space, a hook-knife incised the muscular esophageal wall. The endoscope was then advanced into the mediastinum and chest. Mediastinoscopy and thoracoscopy were performed to identify lymph node stations. Prototype endoscopic devices permitted lymph node dissection prior to removal with an electrocautery snare. A covered prototype stent was placed over the mucosectomy site.

MAIN OUTCOME MEASUREMENTS

Feasibility of endoscopic transesophageal lymphadenectomy.

RESULTS

Three lymph nodes (1 para-aortic and 2 right paratracheal) were removed in the 3 nonsurvival swine. Nine swine were survived for 14 days (range 13-14 days) and had a total of 7 lymph nodes (2 para-aortic and 5 paratracheal) removed. Two swine had no endoscopically visible lymph nodes in the mediastinum or chest. Lymph node dissection and resection was successful in all cases where lymph nodes were identified. Lymphadenectomy was completed in a median time of 20.0 minutes (range 8-60 minutes); median total procedure time was 70.0 minutes (range 28-105 minutes). Median lymph node size was 1.1 cm (range 0.6-1.4 cm).

LIMITATIONS

Animal study.

CONCLUSION

An endoscopic transesophageal approach can accomplish mediastinal lymph node dissection and en bloc resection and provides architecturally intact lymph node specimens for histologic examination.

International multicenter trial on clinical natural orifice surgery--NOTES IMTN study: preliminary results of 362 patients

OBJECTIVES

Natural orifice translumenal endoscopic surgery (NOTES) is evolving as a promising alternative for abdominal surgery. IMTN Registry was designed to prospectively document early results of natural orifice surgery among a large group of clinical cases.

METHODS

Sixteen centers from 9 countries were approved to participate in the study, based on study protocol requirements and local institutional review board approval. Transgastric and transvaginal endoscopic natural orifice surgery was clinically applied in 362 patients. Intraoperative and postoperative parameters were prospectively documented.

RESULTS

Mean operative time for transvaginal cholecystectomy was 96 minutes, compared with 111 minute for transgastric cholecystectomy. A general complication rate of 8.84% was recorded (grade I-II representing 5.8%, grade III-IV representing 3.04%). No requirement for any analgesia was found in one fourth of cholecystectomy and appendectomy patients.

CONCLUSIONS

Results of clinical applications of NOTES in the IMTN Study showed the feasibility of different methods of this new minimally invasive alternative for laparoscopic and open surgery.

Stent placement provides safe esophageal closure in thoracic NOTES(TM) procedures

BACKGROUND

Safe esophageal closure remains a challenge in transesophageal Natural Orifice Transluminal Endoscopic Surgery (NOTES). Previously described methods, such as suturing devices, clips, or submucosal tunneling, all have weaknesses. In this survival animal series, we demonstrate safe esophageal closure with a prototype retrievable, antimigration stent.

METHODS

Nine Yorkshire swine underwent thoracic NOTES procedures. A double-channel gastroscope equipped with a mucosectomy device was used to create an esophageal mucosal defect. A 5-cm submucosal tunnel was created and the muscular esophageal wall was incised with a needle-knife. Mediastinoscopy and thoracoscopy were performed in all swine; lymphadenectomy was performed in seven swine. A prototype small intestinal submucosal (SurgiSIS(®)) covered stent was deployed over the mucosectomy site and tunnel. Three versions of the prototype stent were developed. Prenecropsy endoscopy confirmed stent location and permitted stent retrieval. Explanted esophagi were sent to pathology.

RESULTS

Esophageal stenting was successful in all animals. Stent placement took 15.8 ± 4.8 minuted and no stent migration occurred. Prenecropsy endoscopy revealed proximal ingrowth of esophageal mucosa and erosion with Stent A. Mucosal inflammation and erosion was observed proximally with Stent B. No esophageal erosion or pressure damage from proximal radial forces was seen with Stent C. On necropsy, swine 5 had a 0.5-cm periesophageal abscess. Histology revealed a localized inflammatory lesion at the esophageal exit site in swine 1, 3, and 9. The mucosectomy site was partially healed in three swine and poorly healed in six. All swine thrived clinically, except for a brief period of mild lethargy in swine 9 who improved with short-term antibiotic therapy. The submucosal tunnels were completely healed and no esophageal bleeding or stricture formation was observed. All swine survived 13.8 ± 0.4 days and gained weight in the postoperative period.

CONCLUSIONS

Esophageal stenting provides safe closure for NOTES thoracic procedures but may impede healing of the mucosectomy site.

Future applications of flexible endoscopy in esophageal surgery

INTRODUCTION

Flexible endoscopy has long played a role in esophageal surgery, and procedures like perforation closure, stenting of occluding malignancies, antireflux procedures, and removal of Barretts are increasingly replacing open and laparoscopic procedures. We present early results of a series of acute animal experiments studying the feasibility of using flexible endoscopes for complex esophageal surgery such as Heller myotomy and esophagectomy.

METHODS

A total of six animals and one human cadaver have been operated on in a series of three protocols. The first study involves extraluminal flexible endoscopy through a cervical incision. The esophagus is dissected to the phrenoesophageal junction and a Heller myotomy performed. The second study involves labeling specific mediastinal node areas using EUS and transesophageal tattooing. Transcervical access is once again obtained, and wide esophageal dissection is performed; sequential identification of the marked nodes is performed. The final study involves full thoracic esophageal mobilization and laparoscopic gastric mobilization for an esophagogastrectomy.

RESULTS

Heller myotomy in five animals was performed via flexible endoscopy. Total operative time was 49 min with mean time for myotomy being 22 min. One animal had hemodynamic compromise from over insufflating the mediastinum with air. The second study involved three animals and one human cadaver. An average of four nodes was marked by EUS, and there was 100% success in identifying all nodes with flexible medistinoscopy. Operative times had a mean of 187 min (147-227) for the animal model and 198 min for the cadaver model.

CONCLUSION

There is a move to increase the role of flexible endoscopy in GI surgery. This is facilitated by the introduction of novel scopes and instrumentation designed for NOTES. We outline early favorable results from animal studies looking at the use of flexible endoscopy as a surgical tool for Heller myotomy and esophagectomy.

Natural orifice transesophageal thoracoscopic surgery: A review of the current state

Since the concept of Natural Orifice Translumenal Endoscopic Surgery (NOTES) was introduced, it has continued to gain significantly in popularity and enthusiasm for its potential clinical applications. The ability to perform conventional laparoscopic and thoracoscopic procedures without the creation of scars and perhaps faster and less painful recovery has prompted a worldwide devotion to further this field. While intra-abdominal NOTES has rapidly transitioned from animal models to human trials, applying the NOTES concept to perform thoracic procedures has been slower to gain momentum. The goal of this review is to summarize the current state of transesophageal NOTES thoracoscopy by looking at its potential for diagnostic and therapeutic interventions as well as the challenges in transitioning to human trials.

Natural Orifice Trans-Luminal Endoscopic Surgery in the esophagus

As limited as are the studies regarding peritoneal Natural Orifice Trans-Luminal Endoscopic Surgery, mediastinal transluminal experiments are certainly in their infancy. The authors evaluate the parallel development of minimally invasive thoracic surgery with regard to its counterpart in peritoneal laparoscopy to NOTES. Transesophageal interventions by both endosonographic and direct visualization are examined in the context of minimally invasive surgery and mediastinal NOTES. Techniques of viscerotomy creation, visualization, and closure are examined with particular emphasis on mediastinal structures. The state of current interventions is examined. Finally, current morbidity (including infectious complications) and survival outcomes are examined in those animals that have undergone transesophageal exploration.

Feasibility of endoscopic transesophageal thoracic sympathectomy (with video)

BACKGROUND

Thoracoscopic sympathectomy is the preferred surgical treatment for patients with disabling palmar hyperhidrosis. Current methods require a transthoracic approach to permit ablation of the thoracic sympathetic chain.

OBJECTIVE

To develop a minimally invasive, transesophageal endoscopic technique for a sympathectomy in a swine model.

DESIGN

Nonsurvival animal study.

SETTING

Animal trial at a tertiary care academic center.

SUBJECTS

This study involved 8 healthy Yorkshire swine.

INTERVENTIONS

After insertion of a double-channel gastroscope, a Duette Band mucosectomy device was used to create a small esophageal mucosal defect. A short, 5-cm submucosal tunnel was created by using the tip of the endoscope and biopsy forceps. Within the submucosal space, a needle-knife was used to incise the muscular esophageal wall and permit entry into the mediastinum and chest. The sympathetic chain was identified at the desired thoracic level and was ablated or transected. The animals were killed at the completion of the procedure.

MAIN OUTCOME MEASUREMENTS

Feasibility of endoscopic transesophageal thoracic sympathectomy.

RESULTS

The sympathetic chain was successfully ablated in 7 of 8 swine, as confirmed by gross surgical pathology and histology. In 1 swine, muscle fibers were inadvertently transected. On average, the procedure took 61.4+/-24.5 minutes to gain access to the chest, whereas the sympathectomy was performed in less than 3 minutes in all cases. One animal was killed immediately after sympathectomy, before the completion of the observation period, because of hemodynamic instability.

LIMITATIONS

Nonsurvival series, animal study.

CONCLUSIONS

Endoscopic transesophageal thoracic sympathectomy is technically feasible, simple, and can be performed in a porcine model.

Loop-anchor purse-string versus endoscopic clips for gastric closure: a natural orifice transluminal endoscopic surgery comparison study using burst pressures

BACKGROUND

The success of natural orifice surgery depends on a reliable, secure closure of the opening in the gut. Few tests of the integrity of these closures have been published.

OBJECTIVE

To determine whether a gastrotomy can be closed safely and effectively from within the stomach by using looped T-anchors-a novel, endoscopically placed device.

DESIGN

Head-to-head comparison trial of 2 closure methods in 9 explanted porcine stomachs.

SETTING

Animal laboratory.

INTERVENTION

Paired gastrotomies were made in porcine explants. One was closed by using endoscopic clips, and the other was closed by using modified T-anchors in a purse-string fashion.

MAIN OUTCOME MEASUREMENTS

Gastric transmural pressure gradients at bursting of these closures were measured while the explanted stomachs were inflated with a high-pressure insufflator.

RESULTS

The mean burst pressure of the looped T-anchors was 27.3 mm Hg, whereas that of the clip closures was 14 mm Hg. By using 10 mm Hg as a threshold for a "secure" closure, 7 of 9 clip closures failed to meet the threshold value, whereas all 9 of the T-anchor closures met or exceeded the threshold value (P = .0023, 2-tailed Fisher exact test).

LIMITATION

Nonsurvival study.

CONCLUSION

Looped T-anchors provide a secure gastric closure for natural orifice surgery and are superior to endoscopic clips for this purpose.