Peroral transgastric organ resection: a feasibility study in pigs

Current developments in natural orifices transluminal endoscopic surgery: An evidence-based review

Tremendous advances have been made in recent years addressing the key obstacles to safe performance and introduction of human natural orifice transluminal endoscopic surgery (NOTES). Animal studies have focused on identifying optimal solutions to these obstacles, in particular methods of creating transluminal access, safe closure of the point of access, and development of a multitasking platform with dedicated instruments. Whether the performance data generated from these animal studies can be reproduced in humans has yet to be determined. Reports of human NOTES procedures are emerging, and the possibility of accomplishing human NOTES based on existing technology has been demonstrated. However, dedicated platforms and devices are still lacking to allow for pure NOTES procedures, and whether NOTES can deliver the postulated benefits of earlier recovery and improved cosmesis remains uncertain.

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.

Expandable gastric port for natural orifice translumenal endoscopic surgery

BACKGROUND

The risk of intraabdominal contamination is a critical consideration during most natural orifice translumenal endoscopic surgery (NOTES) procedures.

OBJECTIVE

The objective of this study was to determine a safe and efficient pathway for the endoscope in a transgastric NOTES procedure.

DESIGN AND SETTINGS

A pilot experimental study in live pigs was performed.

METHODS

Five White Landrace pigs, weighing approximately 30-35 kg, underwent the placement of a device consisting of an expandable sheath, the distal portion of which was composed of a fully covered self-expanding metal stent, and an introducer made with an outer catheter, a pushing catheter, and an inner, guiding catheter. The sheath was attached to the stent by suturing it in place. The initial gastric opening was made by means of a needle knife papilotome with electrocoagulation, aimed to the anterior gastric wall. Then, it was dilated with an endoscopic 1.8-cm balloon. The set was introduced over a Savary guidewire. After the set placement, the outer tube was slowly retrieved. Finally, the delivery system was removed from the pig, leaving the entire endoscopic port in place.

RESULTS

The expandable gastric port was placed without difficulty in all animals. Endoscope insertion into the expandable gastric port was very easily performed. The endoscope had a wide range of movement inside the peritoneal cavity. The gastric port sealed the gastric wall, avoiding gross contamination of the peritoneal cavity and maintaining the pneumoperitoneum without excessive inflation of the intestine.

CONCLUSIONS

Use of a gastric port can minimize contamination of the peritoneal cavity due to the spillage of gastric contents during a transgastric NOTES procedure and can also facilitate performance of the procedure.

Durability of the self-approximating translumenal access technique (STAT) for potential use in natural orifice translumenal surgery (NOTES)

BACKGROUND

The self-approximating translumenal access technique (STAT) has been shown to provide a safe and reliable means of abdominal access for natural orifice translumenal endoscopic surgery (NOTES). However, the feasibility of using STAT for translumenal organ resection is unknown. This study aimed to evaluate the technical performance of organ resection using STAT, the integrity of the STAT gastric tunnel after organ resection, and the postoperative morbidity of organ resection using STAT.

METHODS

In this study, 14 domestic swine underwent transgastric organ resection (7 cholecystectomies, 7 uterine horn resections) followed by sequential removal of two different sizes of standardized specimens. Evaluation of operative injury to the tunnel and difficulty of specimen extraction was performed. After 2 weeks of observation, necropsy was performed for evaluation and documentation of gross findings.

RESULTS

The mean operating room time (intubation recovery) was 4.1 h. A tunnel with a mean length of 12 cm and a mean width of 4 cm was created. The tunnel remained fully intact in 14 of 14 animals after organ resection, in 13 of 13 animals after balloon extraction, and in 12 of 14 animals after rigid specimen extraction (1 clinically significant tear occurred). Postoperatively, all the animals gained weight appropriately. Necropsy findings included adhesions (n = 4), bile leak (n = 2), minor lap-port abscess (n = 1), and ventral hernia (n = 1).

CONCLUSIONS

Although this study was a limited, prospective, animal survival study without a control arm, it again indicates that STAT allows safe abdominal access, a reliable means of closure, and directed endoscope positioning. Although one significant mucosal tear did occur, this study suggests STAT will tolerate the mechanical forces of peroral transgastric procedures provided the organ resected is small to moderate in size (<8 × 3 cm).

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.

Impact of body image on patients' attitude towards conventional, minimal invasive, and natural orifice surgery

PURPOSE

A series of investigations proposed that patients' preference on minimal invasive and scarless surgery may be influenced by age, sex, and surgical as well as endoscopic history of the individual patient. However, it is unknown which psychological criteria lead to the acceptance of increased personal surgical risk or increased personal expenses in patients demanding scarless operations. We investigated whether individual body image contributes to the patient's readiness to assume higher risk in favor of potentially increased cosmesis.

MATERIALS AND METHODS

We conducted a nonrandomized survey among 63 consecutive surgical patients after receiving surgery. Individual body image perception was assessed postoperatively applying the FKB-20 questionnaire extended by four additional items. The FKB-20 questionnaire is a validated tool for measuring body image disturbances resulting in a two-dimensional score with negative body image (NBI) and vital body dynamics (VBD) being the two resulting scores. A subgroup analysis was performed according to the conducted operations: conventional open surgery = group 1, traditional laparoscopic surgery = group 2, and no scar surgery = group 3.

RESULTS

There was a significant correlation between a negative body image and the preference for scar sparing and scarless surgery indicated by a significantly increased acceptance of surgical risks and the willingness to spend additional money for receiving scarless surgery (r = 0.333; p = 0.0227). Allocated to operation subgroups, 17 of 63 patients belonged to group 1 (OS), 29 to group 2 (minimally invasive surgery), and 17 patients to group 3 (no scar). Although age and sex were unequally distributed, the groups were homogenous regarding body mass index and body image (NBI). Subgroup analysis revealed that postoperative desire for scar sparing approaches was most frequently expressed by patients who received no scar operations.

CONCLUSIONS

Patients with an NBI tend towards scarless surgery and are willing to accept increased operative risk and to spend additional money for improved postoperative cosmesis.

Transgastric organ resection solely with the prototype R-scope and the self-approximating transluminal access technique

BACKGROUND

The self-approximating transluminal access technique (STAT) has been demonstrated to provide safe transluminal access and in-line endoscope positioning to target abdominal organs during natural orifice transluminal endoscopic surgery (NOTES). To date, organ resection with NOTES has typically required percutaneous assistance. We hypothesized that the in-line positioning and partial stability provided by STAT would allow single-access NOTES procedures if a multiarticulated endoscope could be used.

OBJECTIVE

Assessment of single-site NOTES, using STAT and a prototype, multi-articulated endoscope.

DESIGN

Animal survival study.

SETTING

Penn State Hershey Medical Center Research Laboratories.

INTERVENTIONS

Thirteen pigs underwent NOTES using a prototype endoscope with 2 articulated channels, a grasping forceps, and an insulated-tip needle-knife. The gallbladder was dissected using a fundus down technique, and hemoclips and a detachable loop were placed on the cystic duct and artery before removal. After a 2- to 3-week observation period, animals were euthanized and necropsy performed.

RESULTS

All target organs were successfully resected without laparoscopic assistance. Significant complications were 2 perforations (1 caused by a prototype duodenal occlusion device and 1 caused by enterotomy during cholecystectomy) and 1 entrapment of the small bowel with an endoloop. Postoperatively, all animals gained weight appropriately with 1 killed on postoperative day 12 because of lethargy (cystic duct leak/biloma).

LIMITATIONS

This is a limited animal survival study without control arm.

CONCLUSIONS

The combination of the R-scope and STAT does allow effective, single-site NOTES procedures; however, although the R-scope provides improved tissue manipulation and visibility, the complications incurred here suggest that further improvements in devices and technique will be required for safe and effective single-site NOTES procedures.

Natural orifice translumenal surgery: Flexible platform review

Natural orifice translumenal surgery (NOTES) has garnished significant attention from surgeons and gastroenterologists, due to the fusion of flexible endoscopy and operative technique. Preliminary efforts suggest that NOTES holds potential for a less invasive approach with certain surgical conditions. Many of the hurdles encountered during the shift from open to laparoscopic surgery are now being revisited in the development of NOTES. Physician directed efforts, coupled with industry support, have brought about several NOTES specific devices and platforms to help address limitations with current instrumentation. This review addresses current flexible platforms and their attributes, advantages, disadvantages and limitations.

Leaks and endoscopic assessment of break of integrity after NOTES gastrotomy: the LEAKING study, a prospective, randomized, controlled trial

BACKGROUND

Gastric leak testing after natural orifice transluminal endoscopic surgery (NOTES) gastrotomy closure may help reduce the risk of leaks after transgastric procedures.

OBJECTIVE

To develop a novel endoscopy-based system to determine the presence of a leak after NOTES gastrotomy and to compare this system prospectively with radiographic leak testing.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Academic Medical Center laboratory.

SUBJECTS

Fifty swine.

INTERVENTION

During the pretrial phase, an endoscopic system for the measurement of intragastric pressure was developed. In the trial phase, swine with a NOTES gastrotomy were randomized to endoscopic versus radiographic leak testing. If a leak was demonstrated, the gastrotomy was reclosed by using a second-generation prototype T-anchor system. The primary outcome was leak detection after gastrotomy closure. The secondary outcome variables included necropsy findings, peritoneal fluid analysis, histologic examination, and clinical outcome.

RESULTS

Fourteen swine were included in the pretrial phase and 36 in the randomized trial. Swine were survived for a mean of 9 days postoperatively. Endoscopic pressure monitoring demonstrated a reproducible change in intragastric pressure with insufflation; r = 0.735, P = .001 and r = 0.769, P < or = .000 for the total and maximum pressures, respectively. Post-peritoneoscopy, there was a detectable and significant decrease in the mean total and mean maximum pressures versus baseline (P = .006 and P = .009). There was no significant difference between the radiologic and endoscopic arms in leak detection rate (4/18 vs 3/18, respectively, P = .500). Clinical outcomes and mean weight gain were equivalent. There was 1 operative abdominal wall injury and no deaths.

LIMITATIONS

Animal study.

CONCLUSION

Endoscopic pressure monitoring was reproducible, demonstrated the presence of gastric leak, and was as reliable as contrast-based radiographic leak testing.

[Laparoscopic transumbilical cholecystectomy. Results with the gel device and literature review]

INTRODUCTION

The appearance of single transumbilical incision surgery has opened a new era in the minimally invasive approach of cholecystectomy. Specific ports for this technique have made it easier to perform. We report our initial experience, from July 2008 to June 2009 and give an updated bibliographic review.

PATIENTS AND METHODS

A prospective, longitudinal and interventional study that included 30 patients with symptomatic cholelithiasis, from 10 July 2008 to 30 June 2009, on whom a single transumbilical incision laparoscopic cholecystectomy was performed (LESS technique), without other minilaparoscopic ports or traction stitches. A gel port was used for all surgeries (R-Port, Tri-Port), as well as straight and roticulating laparoscopic graspers. Surgical time, analgesia requirements, postoperative hospital stay, conversions and complications were registered.

RESULTS

The median age was 34.8 years (range, from 21 to 53), with a BMI between 21 kg/m(2) and 39.5 kg/m(2) (mean 25.8 kg/m(2)). Surgical time was 65.1 minutes (ranging from 40 to 150) and postoperative length stay was less than 24 hours. Postoperative pain was measured with the VAS scale, giving a low score. Up to now, two wound infections and a bile leak have been observed.

CONCLUSIONS

LESS cholecystectomy is a safe and feasible technique performed by experienced surgeons in minimally invasive surgery, and requires a greater learning curve than that of the conventional laparoscopic cholecystectomy.

Early healing of transcolonic and transgastric natural orifice transluminal endoscopic surgery access sites

BACKGROUND

Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a developing, minimally invasive surgical approach whose potential benefits are being investigated. Little is known about secure access site closure and early healing kinetics of transvisceral access.

STUDY DESIGN

Transvisceral access incisions were created in the colon (C-NOTES, n = 8) and stomach (G-NOTES, n = 8) for peritoneal exploration. Incisions were closed primarily with endoloops, endoclips, or t-tags. Macroscopic and histologic analyses performed on postoperative day 7 assessed gross appearance, granulation tissue, inflammation, ulceration, and complications.

RESULTS

Macroscopically, incisions appeared closed without intraperitoneal spillage. Incisions closed by endoloop and t-tags showed intense granulation tissue fill of defect despite partial (G-NOTES, n = 3) and transmural ulceration (C-NOTES, n = 8; G-NOTES, n = 3). Of the 30 t-tags applied, 40% broke or deployed into the peritoneal cavity. Endoclip closures (C-NOTES, n = 1; G-NOTES, n = 1) did not show histologic mucosal continuity. Healing complications included transmural necrosis (C-NOTES, n = 1; G-NOTES, n = 1), foreign body material (C-NOTES, n = 3; G-NOTES, n = 2), and microabscesses (G-NOTES, n = 1).

CONCLUSIONS

This study provides a reproducible model to assess noninvasive repair of planned visceral perforations. Of investigated technologies, endoloop closure was favored for transcolonic incisions, and t-tags with omental patch for transgastric incisions, although these have significant limitations. Endoclips were inadequate for primary closure, but may be useful as an adjunctive closure modality. Additional studies are needed to examine visceral repair at later time points, as they will help determine the quality and kinetics of repair of a variety of incision closure strategies. This study demonstrates the need for improved technologies to more reliably close visceral transluminal defects.

Infection during natural orifice transluminal endoscopic surgery: a randomized, controlled study in a live porcine model

BACKGROUND

Currently reported natural orifice transluminal endoscopic surgery (NOTES) procedures in animals have been done in heterogeneous milieus ranging from nonsterile to sterile procedures, with mixed results, including no infection in those performed in nonsterile settings.

OBJECTIVE

To establish the potential frequency of infection during NOTES, comparing sterile to nonsterile approaches.

SETTING

Survival experiments on sixteen 50-kg pigs.

DESIGN AND INTERVENTIONS

From pilot data (100% infection frequency after nonsterile procedures), sample size (8 animals in each group) was calculated by using a power of 95% and an alpha risk of 0.05. The animals were randomly assigned to two groups: In the transgastric peritoneoscopy study group, liver and ovarian biopsies were performed with sterile overtubes, endoscopes, and accessories and the use of preoperative intravenous antibiotics and antiseptic gastric lavage. In the nonsterile (control) group, the same procedures were performed with nonsterile endoscopes and accessories without the use of gastric lavage and preoperative antibiotics. Complete transmural closure of the transgastric access site was made in all animals. After a 1-week survival time, all animals were killed for necropsy, which included Gram staining and peritoneal cultures.

MAIN OUTCOME MEASUREMENTS

Intraperitoneal infection on necropsy.

RESULTS

All necropsies revealed intraperitoneal infection (abscesses, fibrinopurulent exudates, and adhesions) in the control group (frequency of infection 100%). Peritoneal bacterial culture grew various aerobic and anaerobic organisms. No gross or bacteriological evidence of infection was seen in the sterile group (frequency of infection 0%, P value = <.0002).

LIMITATIONS

Animal experiments.

CONCLUSION

Nonsterile conditions invariably lead to intraperitoneal infection. Aseptic techniques during NOTES can prevent intra-abdominal infection. Future studies will determine which infection prevention steps are mandatory and which can be omitted during NOTES procedures.

[Natural orifice transluminal endoscopic surgery: current situation]

Natural orifice transluminal endoscopic surgery (NOTES) is an emerging experimental alternative to conventional surgery that eliminates abdominal incisions and incision-related complications by combining endoscopic and laparoscopic techniques to diagnose and treat abdominal pathology. Natural orifice transluminal endoscopic surgery refers to the method of accessing the abdominal cavity through a natural orifice under endoscopic visualization. Since its introduction in 2004, numerous reports have been published describing different surgical interventions. Recently, a group of expert laparoscopic surgeons and endoscopists outlined the limitations of this approach and issued recommendations for progress toward human trials. Transluminal surgery is a new method for accessing the abdomen under direct endoscopic visualization. Preliminary studies have demonstrated the feasibility of this technique in animal models; however, further research is warranted to validate its safety in humans.

Transoral thyroid and parathyroid surgery

BACKGROUND

Translumenal endoscopic interventions via so-called natural orifices are gaining increasing interest because they allow surgical treatment without any incision of the skin. Moreover, minimally invasive procedures have found their way into thyroid and parathyroid surgery. Our goal was to develop a new access for thyroid and parathyroid resection via an entirely transoral approach.

METHODS

We managed to find an entirely transoral sublingual access to the thyroid region in pigs and human cadavers. Using a modified rigid rectoscope (oraloscope) hemithyroidectomies as well as resection of parathyroid glands were performed via this new approach. Preparation and resection was performed using conventional laparoscopic instruments. In living pigs, integrity of the recurrent laryngeal nerve after resection could be documented by neuromonitoring. An absorbable suture was used to seal the mucosal incision.

RESULTS

First, hemithyroidectomy was performed via the transoral access in 10 porcine cadavers, then in 10 living and orally intubated pigs, and finally in five human corpses. In humans, resection of parathyroid glands also was performed. We gained access to the thyroid region by blunt dissection of the layer behind the hyoid bone and the strap muscles of the neck. We did not observe any complication during the insertion, resection, and removal part of the new procedure.

CONCLUSIONS

Entirely transoral thyroid and parathyroid surgery via sublingual access seems to be feasible. However, further investigations are needed to evaluate the safety of the new technique, especially potential and clinically relevant contamination of the access route has to be excluded.

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.

[Diagnostic and interventional endoscopy in gastroenterology : from high-resolution chips and procedures for endoscopic resection to NOTES]

In the past 10 years endoscopic diagnostics has benefited from technologies such as big chips, high-definition television (HDTV) and narrow band imaging (NBI). Video capsule endoscopy and double balloon enteroscopy have facilitated visualization of the entire small bowel. A number of studies on mucosal Barrett's and gastric cancers could prove that endoscopic mucosal resection (EMR) is oncologically equivalent to surgical resection when certain criteria are respected. However, EMR is less invasive and carries a substantially lower complication risk and mortality compared to surgery. Endoscopic submucosal dissection (ESD) facilitates en bloc resection with thorough histopathologic evaluation of the specimen, e.g. for mucosal lesions in the stomach and rectum. Endosonography (EUS) guided transgastric necrosectomy using a flexible gastroscope has set a milestone in the treatment of infected pancreatic necroses and has replaced open surgery in many centers. Natural orifice transluminal endoscopic surgery (NOTES) uses natural body openings as minimally invasive access to the abdomen and mediastinum. Interventional GI endoscopists and minimally invasive surgeons have profited from these innovations in micromechanics and microelectronics.

Microbiological contamination during transgastric and transvaginal endoscopic techniques

Natural orifice transluminal endoscopic surgery (NOTES) has gained widespread interest as a potentially alternative to laparoscopic surgery, but concerns over peritoneal contaminations are unsolved. The aim of our study was to assess the safety of transluminal surgery by investigating the intraperitoneal bacterial load and contamination during transgastric and transvaginal surgeries. Twelve female pigs underwent transgastric (n = 7; tubal ligation and oophorectomy) and transvaginal procedures (n = 5; cholecystectomy). All animals were sacrificed after 2 weeks. The procedures were performed by using a double-channel endoscope (GIF-2T160; Olympus, Tokyo, Japan) under general anesthesia. Peritoneal fluid sampling was taken immediately after entry into the abdomen, at the end of the surgical procedure and during the autopsy, and sent for microbiologic assessment. In the transgastric group, 6 animals completed the surgical procedures and survived. Three pigs experienced signs of postoperative peritonitis with abscesses and adhesions visible and Escherichia Coli isolated at autopsy. In the transvaginal group, a cholecystectomy was performed without technical problems in all animals. No signs of postoperative sepsis nor growth in the microbiologic samples were recorded. In conclusion, the transvaginal approach seemed to be safer and produced less intra-abdominal contamination and sepsis, compared to the transgastric approach. Although both transgastric tubal ligation and oophorectomy and transvaginal cholecystectomy were feasible using equipment and accessories currently available for conventional endoscopy, new procedure-specific instruments and equipment should be developed to allow the operator safer access into the peritoneum.

NOTES: new dimension of minimally invasive surgery

Natural orifice transluminal endoscopic surgery (NOTES) is an emerging experimental alternative to conventional surgery. NOTES eliminates abdominal incisions and incision-related complications by combining endoscopic and laparoscopic techniques to diagnose and treat abdominal pathology. Since the first NOTES was reported by Kalloo et al. in 2004, significant achievements in the laboratory have occurred. Clinical use in humans has been limited, but several cases and one small clinical trial were published recently. As a further technical revolution in minimally invasive surgery, NOTES has the promising potential to be safer, less invasive, provide better cosmesis and possibly be more cost-effective. The purpose of the present article was to review the development and current status of NOTES and highlight important advances associated with this innovative approach.

Natural orifice versus conventional laparoscopic distal pancreatectomy in a porcine model: a randomized, controlled trial

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) research has primarily involved case series reports of low-risk procedures. Distal pancreatectomy has significant postoperative morbidity and would permit rigorous examination in a controlled trial setting.

OBJECTIVE

To compare endoscopic transgastric distal pancreatectomy (ETDP) and laparoscopic distal pancreatectomy (LDP).

DESIGN

Prospective, randomized, controlled trial.

SETTING

Academic hospital.

SUBJECTS

Forty-one swine, 28 block randomized.

INTERVENTIONS

LDP was performed with 3 trocars and stapled transection of the pancreas. ETDP was performed via a gastrotomy, with 1 trocar for visualization, by using endoloop placement, snare transection, and purse-string gastrotomy closure.

MAIN OUTCOME MEASUREMENTS

Clinical examination, CT, serum chemistries, necropsy, peritoneal fluid analysis, and histologic examination.

RESULTS

Swine were survived for 8 days. The procedure time for ETDP was significantly greater than for LDP (1:52 vs 0:33 [hours:minutes]; P = .00). Pancreatic specimen weight was similar (4.1 g vs 5.5 g; P = .108). Postoperatively, 26 of 28 animals thrived. In the LDP group, 1 death caused by pancreatic leak and renal failure occurred on day 1. In the ETDP group, 1 death caused by pneumothorax occurred intraoperatively. The necropsy, CT, and histologic examinations revealed focal resection-margin necrosis in 3 to 7 swine in the ETDP group with no proximal necrosis or pancreatitis. The groups were equivalent clinically, by survival, and by serum and peritoneal fluid analysis. The gastrotomy closure was associated with small serosal adhesions, but no gross abscess or necrosis.

LIMITATION

Animal study.

CONCLUSIONS

In the largest controlled trial of NOTES orifice surgery to date, there was no clinical or survival difference between NOTES and laparoscopic approaches.

Anatomical considerations for natural orifice translumenal endoscopic surgery

Success in surgical procedures relies on the surgeon's understanding of anatomy and the ways in which the internal organs relate to one another. Recently, a new surgical technique has been introduced. Natural orifice translumenal endoscopic surgery (NOTES) uses the body's natural orifices (mouth, anus, urethra, or vagina) as entrance points to the peritoneal cavities (through the stomach, rectum, bladder, or posterior vaginal fornix). NOTES techniques have proven feasible in both animal and early human trials. While it remains to be seen what advantages NOTES possesses over traditional surgical approaches, a clear understanding of human anatomy will be critical for successful, safe NOTES procedures. This article summarizes the development and the basic techniques of NOTES and reviews those anatomical considerations specific to NOTES.

Appendicectomy and cholecystectomy using single-incision laparoscopic surgery (SILS): the first UK experience

INTRODUCTION

Single-incision laparoscopic surgery (SILS) has the potential advantages of reduced postoperative pain and reduced port-site complications. Careful attention to closure can lead to virtually "scarless" surgery. In this article, we present our first experiences with SILS appendicectomy and cholecystectomy.

METHOD

SILS appendicectomy and cholecystectomy was performed in 12 and 14 patients, respectively. Data were collected prospectively and analyzed retrospectively from case notes and the theater database.

RESULTS

The average operating times were 61.3 and 142.9 minutes for SILS appendicectomy and SILS cholecystectomy, respectively. There was a good correlation between increasing experience and a reduction in operative time with Pearson's coefficient being -1 for appendicectomy and -0.56 for cholecystectomy. There were no postoperative complications in the SILS appendicectomy group. One patient in the SILS cholecystectomy group suffered a postoperative biliary leak from an accessory duct of Lushka.

CONCLUSIONS

In our series, we have demonstrated SILS to be a safe and efficacious method for appendicectomy and cholecystectomy. Further studies are required to investigate any potential advantages of this method over standard laparoscopic techniques.

Comparison of Transgastric NOTES and laparoscopic peritoneoscopy for detection of peritoneal metastases

BACKGROUND

Transgastric peritoneoscopy (TGP) may be a future alternative to the diagnostic laparoscopy (LAP).

OBJECTIVE

To create a model of peritoneal metastases for development of TGP and to employ this model to compare TGP to LAP.

METHODS

Small beads were stapled in porcine peritoneal cavities to simulate metastases. Using a noninferiority design a sample size of 64 beads was determined, which were divided over 12 animals. Randomization was performed for number and location of beads. LAP was performed by one of 2 blinded surgeons. TGP was then performed in the same pig using either standard endoscopic accessories (TGP-s) or a specially designed toolkit (TGP-t) in randomized order by 1 of 2 blinded endoscopists. Primary outcome was number of beads found and touched during peritoneoscopy.

RESULTS

Locations of beads included: abdominal peritoneum (14 beads), diaphragm (11), surface of liver and hepatoduodenal ligament (32), and miscellaneous sites (7). LAP detected 61 beads (yield = 95%), TGP-s 40 beads (63%), and TGP-t 40 beads (63%). TGP-s and TGP-t were both inferior in comparison with LAP (P = 0.8465 and P = 0.7440 respectively). TGP-s and TGP-t were similar in number, distribution and time to detect beads. TGP was superior for detecting beads on the abdominal and diaphragmatic peritoneum than for the liver, namely TGP-s: 23/25 (92%) versus 12/32 (38%) (P < 0.001); TGP-t: 25/25 (100%) versus 11/32 (34%) (P < 0.001).

CONCLUSION

In this first prospective, blinded, comparative trial TGP was inferior to LAP for the detection of simulated metastases. Future development for NOTES peritoneoscopy should focus on improved access to the region of the liver and enhanced endoscopic optics and performance.

[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.

NOTES transvaginal nephrectomy: first human experience

OBJECTIVES

To present the operative outcomes of the first natural orifice translumenal endoscopic surgery (NOTES) transvaginal nephrectomy.

METHODS

A 57-year-old woman with hypertension, right-sided flank pain, and radiographic evidence of an atrophic right kidney consented for NOTES transvaginal nephrectomy. Pneumoperitoneum was achieved with a Veress needle inserted deep in the umbilicus. Under direct vision, a colpotomy was made and a transvaginal port positioned. Using standard and articulating operating instruments inserted transvaginally, the kidney was mobilized and the renal hilum was controlled with an endovascular stapler. The kidney was placed in a laparoscopic retrieval bag and extracted through the vaginal incision. Salient demographic and operative data were obtained.

RESULTS

NOTES transvaginal nephrectomy was successfully completed, with all the operative steps performed transvaginally. Dense pelvic adhesions from a prior hysterectomy necessitated the use of a 5-mm umbilical port during vaginal port placement and for retraction of the ascending colon during division of the renal hilum. No intraoperative complications occurred. Operative time was 307 minutes, with 124 minutes dedicated to vaginal port placement and 183 minutes dedicated to adhesiolysis and nephrectomy. The duration of hospitalization was 23 hours. The visual analog pain scale score was 1 of 10 on postoperative day 2.

CONCLUSIONS

Our experience shows that NOTES transvaginal nephrectomy is technically feasible. Access to the peritoneal cavity should be performed under visual guidance and after insufflation through the umbilicus. Additional experience is needed to better define patient selection criteria and indications for NOTES transvaginal urologic surgery.

Principle and history of Natural Orifice Translumenal Endoscopic Surgery (NOTES)

The field of gastrointestinal endoscopy has been witnessing major advances over the last five decades. Developing from flexible endoscopy to endoscopic retrograde cholangiopancreatography (ERCP) in the 1950's and 70's to endoscopic ultrasound in the 80's, endoscopic technology has been transformed from serving purely diagnostic purposes to therapeutic applications. One recent major advance is the notion of using the flexible endoscope, taking it beyond the gastrointestinal lumen into what lies beyond the confines of the gastrointestinal tract. Natural orifice translumenal surgery offers the exciting potential to be safer, less invasive and possibly more cost-effective than the traditional open surgical or laparoscopic approach. The history and principles of natural orifice translumenal endoscopic surgery (NOTES), along with future implications, are outlined in this article.

The history of NOTES

Throughout history, medicine has witnessed paradigm shifts that significantly change patient treatment. Recently, the introduction and development of laparoscopic surgery has had a major impact on patient treatment. On the horizon is natural orifice translumenal endoscopic surgery (NOTES), which has tremendous potential. This review focuses on the history of natural orifice endoscopy in urology with the progression through therapeutic natural orifice endoscopy and resection to the development of upper tract natural orifice surgery. Further delineated is how technology has improved these procedures to set the stage for NOTES.

Status of access and closure techniques for NOTES

Natural orifice translumenal endoscopic surgery (NOTES) is a novel surgical concept that may provide a multitasking platform for minimally invasive surgery in the 21st century. With NOTES, natural hollow organs are used to gain access to body cavities via the mouth, anus, vagina, and urethra, thereby eliminating skin incisions. Access to the body cavity through the entry portal for the NOTES procedure and closure of the portal after surgery are important treatment considerations. In this review, access and closure techniques for NOTES-related procedures are discussed. Technical descriptions for access are also described. Closure techniques using experimental and commercially available devices are also reviewed. Based on the experimental and early clinical experiences to date, the future of NOTES appears quite promising. Nonetheless, ongoing fundamental research is necessary to determine the safety and benefit of these procedures. While technical challenges are currently present, the issues are being resolved with the development of optimal instrumentation and techniques. We believe that once standardized safe and reliable access and closure techniques are established, a major shift in minimally invasive surgery will likely be inevitable.

Feasibility study of natural orifice transluminal endoscopic surgery inguinal hernia repair

BACKGROUND

A potentially less-invasive technique, transluminal surgery, may reduce or eliminate pain and decrease time to full return of activities after abdominal operations. Inguinal hernia repair is perfectly suited to the transgastric endoscopic approach and has not been previously reported.

OBJECTIVE

Our purpose was to evaluate the feasibility of transgastric bilateral inguinal herniorrhaphy (BIH).

DESIGN

Feasibility study with a nonsurvival canine model.

INTERVENTIONS

Under general anesthesia, male mongrel dogs weighing 20 to 30 kg had a dual-channel endoscope introduced into the peritoneal cavity over a percutaneously placed guidewire. An overtube with an insufflation channel was used. Peritoneoscopy was performed, and bilateral deep and superficial inguinal rings were identified. The endoscope was removed, premounted with a 4 x 6 cm acellular human dermal implant and then readvanced intraperitoneally through the overtube. The implant was then deployed across the entire myopectineal orifice and draped over the cord structures. Bioglue was then applied endoscopically, and the implant was attached to the peritoneum. After completion of bilateral repairs, the animals were killed and necropsy performed.

RESULTS

Five dogs underwent pure natural orifice transluminal endoscopic surgery (NOTES) intraperitoneal onlay mesh (IPOM) BIH. Accurate placement and adequate myopectineal coverage was accomplished in all subjects. At necropsy no injuries to the major structures were noted but Bioglue misapplication with contamination of unintended sites did occur.

LIMITATIONS

Our study involved only a small number of subjects in nonsurvival experiments, and no gastric closure was used.

CONCLUSIONS

Many of the characteristics of inguinal hernia repair are especially well suited to the transgastric approach. The repair is in line with the transgastric endoscope vector, bilateral defects are adjacent, and the IPOM technique does not require significant manipulation or novel instrumentation.

Omentoplasty for gastrotomy closure after natural orifice transluminal endoscopic surgery procedures (with video)

INTRODUCTION

The utility of the greater omentum has not been assessed in transluminal access closure after natural orifice transluminal endoscopic surgery (NOTES) procedures.

OBJECTIVE

Our purpose was to evaluate the feasibility, efficacy, and safety of omentoplasty for gastrotomy closure.

METHODS AND PROCEDURES

Survival experiments in 9 female 40-kg pigs were randomly assigned to 3 groups: group A, endoscopic full-thickness resection (EFTR) for transgastric access and peritoneoscopy without closure; group B, ETFR and peritoneoscopy with omentoplasty (flap of omentum is pulled into the stomach and attached to the gastric mucosa with clips but no clips are used for gastrotomy closure itself); group C, balloon dilation for opening and peritoneoscopy followed by omentoplasty for closure. The animals were observed for 2 weeks and then underwent endoscopy and necropsy with histologic evaluation.

RESULTS

Transgastric opening and peritoneoscopy were achieved in all pigs. In groups B and C, a flap of omentum was easily placed to seal the gastrotomy and then attached to the gastric mucosa with 2 to 5 clips (median 4) in 7 to 20 minutes (median 15 minutes). In group A, peritonitis developed in all animals. In both groups B and C, all animals survived 15 days with no peritonitis and minimal adhesions outside the gastrotomy site. In addition, all achieved complete healing (transmural, n = 4; mucosal ulceration, n = 2) of the gastrotomy site. One animal in group B had an 18-mm abscess in the omental flap.

LIMITATIONS

Animal model, small sample size, lack of appropriate controls for group C.

CONCLUSIONS

Omentoplasty of the gastrotomy site is a technically feasible method to seal balloon-created transgastric access to the peritoneal cavity after NOTES procedures.

Natural orifice transluminal endoscopic surgery

In the past few years, endoscopy has been enriched by a novel concept, natural orifice transluminal endoscopic surgery (NOTES). In this innovative endoscopic technique abdominal organs are approached through natural orifices (mouth, anus, and vagina) in order to perform intra-abdominal diagnostic and therapeutic procedures. Moreover, endoscope is inserted into preexisting orifices to access the other body cavities (i.e. thoracic cavity). Unlike standard surgical procedures, NOTES avoids the need for abdominal incision, and also offers specific advantages in selected patient populations. Although major barriers remain, the demand for a truly scarless, safe, and minimally invasive surgery will promote a rapid development of NOTES technology. This review aimed to elucidate the history, experimental study, clinical application of NOTES.

Minimal contamination of the human peritoneum after transvesical incision

BACKGROUND AND PURPOSE

The recent literature has questioned the infectious risk of natural orifice translumenal endoscopic surgery (NOTES). The need for a clean portal of entry may be important to minimize peritoneal contamination after NOTES. Our study examines the resultant microbial contamination of the human peritoneum after transvesical incision and exposure of the abdomen to bladder contents during robot-assisted laparoscopic prostatectomy (RALP) to better understand the potential for infection in transvesical NOTES.

PATIENTS AND METHODS

Sixty consecutive men undergoing RALP for clinically localized prostate adenocarcinoma from January to May 2008 were prospectively studied as part of a database approved by an Institutional Review Board. The patient's preoperative urine microscopy values, complete blood cell count, and prostate-specific antigen (PSA) levels were recorded, along with the total length of time the cystotomy was open to the peritoneum. Intraoperative samplings of peritoneal fluid were collected before and after transvesical incision and sent for anaerobic, aerobic and fungal cultures.

RESULTS

Patients undergoing RALP had peritoneal exposure after transvesical incision for an average of 118 minutes. Five of 60 (8.3%) patients had evidence of novel aerobic bacterial contamination of the peritoneum after RALP. No patient had a positive anaerobic culture or fungal culture from the peritoneum. Preoperative serum leukocyte and PSA levels were elevated in patients with peritoneal contamination (P < 0.05). Remaining clinicopathologic features, total operative time, or open cystotomy time did not predict peritoneal contamination.

CONCLUSION

Prolonged peritoneal exposure to bladder contents demonstrates minimal contamination of the abdominal cavity and is without postoperative infectious significance. This study may overestimate bacterial contamination via the bladder during RALP, because the specific bacteria seen may have originated from the seminal or prostatic fluid during prostatectomy. Transvesical incision would effectively be a clean portal of entry for NOTES with its low rate of peritoneal contamination.

Oophorectomy by natural orifice transluminal endoscopic surgery: feasibility study in dogs

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) represents a potentially less-invasive alternative to conventional or laparoscopic surgery.

OBJECTIVE

Our purpose was to develop a canine oophorectomy model for prospective evaluation of intraoperative complications, surgical stress, and postoperative pain and recovery with NOTES.

DESIGN

Feasibility study.

SETTING

Academic preclinical research.

PATIENTS

Ten healthy female dogs.

INTERVENTIONS

NOTES procedures were performed through gastric access with an electrocautery snare to resect and retrieve the ovaries. The gastrotomy was closed with prototype T-fasteners.

MAIN OUTCOME MEASUREMENTS

Operative time; complications; postoperative pain scores, and nociceptive threshold; surgical stress markers (interleukin-6 [IL-6], C-reactive protein); systemic stress parameters (cortisol, glucose); necropsy evaluation at 10 to 14 days.

RESULTS

The mean operative time was 154 minutes (SD +/- 58 minutes) and no animals died as a result of complications from the procedure. The primary difficulty was incomplete ovarian excision and conversion to an open procedure in 1 dog. Serum glucose concentrations increased after surgery and remained elevated for at least 36 hours. The serum cortisol concentration was transiently increased from baseline at 2 hours after surgery. The serum IL-6 concentration peaked at 2 hours after surgery and returned to the baseline value by 18 hours. The serum C-reactive protein concentration increased significantly from baseline, peaked at 12 hours after surgery, and then slowly declined toward baseline but remained elevated at 72 hours after surgery. Nociceptive threshold measurements indicated increased sensitivity to pain for 2 to 24 hours after surgery. At necropsy, surgical sites were healing uneventfully with no significant damage to surrounding organs, no significant growth on bacterial cultures, and no evidence of peritonitis.

LIMITATIONS

Small number of animals, single center.

CONCLUSIONS

The NOTES approach to oophorectomy in dogs appears to be a reasonable alternative to traditional surgery. Attention must be paid to ensure complete excision of the ovaries.

Feasibility of transgastric and transcolonic natural orifice transluminal endoscopic surgery peritoneoscopy combined with intraperitoneal EUS

BACKGROUND

If natural orifice transluminal endoscopic surgery (NOTES) peritoneoscopy is to become an alternative to diagnostic laparoscopy, NOTES peritoneoscopy must be comparable to laparoscopy in its diagnostic accuracy.

OBJECTIVE

To assess the feasibility of transgastric (TG) and transcolonic (TC) NOTES peritoneoscopy combined with intraperitoneal EUS.

DESIGN

Twelve nonsurvival experiments on 6 female pigs.

SETTING

Animal laboratory.

PATIENTS

Six 35- to 40-kg female pigs.

INTERVENTIONS

Randomization was performed to determine the order of approach (TG or TC as first procedure). After peritoneal access, systematic peritoneoscopy was performed according to a preassessed list of 12 locations considered clinically important. For each visualized location, 1 point was scored and 1 point added if it was touched as well, leading to a maximum score of 24 points. Subsequently, the endoscope was exchanged for a linear EUS-scope. The percentage of visualization of the 4 sections of the liver was recorded (0, not visible; 1, 33%; 2, 66%; 3, 100%; maximum score, 12 points). After withdrawal, the protocol was repeated by using the second natural orifice (TG or TC).

MAIN OUTCOME MEASUREMENTS

Extent of adequate visualization of diagnostic peritoneoscopy and intraperitoneal EUS measured by a preassessed record form.

RESULTS

Access was achieved without difficulties at all 12 sites. TG peritoneoscopy resulted in a median of 23 points (range 20-24) via the TC approach. A maximum of 24 points was recorded in all pigs (P = .102). TG-EUS resulted in a median of 11 points (range 6-12) and TC-EUS in a median of 12 points (range 8-12) (P = .317).

LIMITATION

Lack of objective landmarks for EUS.

CONCLUSIONS

TG and TC NOTES peritoneoscopy combined with intraperitoneal EUS is technically feasible. Furthermore, NOTES peritoneoscopy and intraperitoneal EUS seem to result in adequate visualization of the peritoneal cavity and liver, respectively.

Transluminal endosurgery: novel use of endoscopic tacks for the closure of access sites in natural orifice transluminal endoscopic surgery (with videos)

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) is a novel and potentially less-invasive alternative to laparoscopic surgery. Successful reproducible secure closure of the transluminal access site represents one of the largest obstacles in the evolution of this discipline.

AIM

To study the feasibility and efficacy of a novel transluminal closure device in a live porcine model.

DESIGN

Experimental endoscopic study of transgastric incision and closure with a novel device in a porcine survival model. Six survival experiments were conducted on Yorkshire pigs that weighed 22 to 25 kg.

INTERVENTIONS

After general anesthesia was administered, a therapeutic endoscope was inserted into the stomach. Two gastrotomies were made in each pig by using a needle-knife with blended current, a guidewire, and an 18-mm through-the-scope dilating balloon. The peritoneum was easily accessed in all pigs without complications. One gastrotomy was closed with T-tag fasteners and the other one with endoscopic tacks. Two different closure methods were used with the tacks: the anchor-and-loop technique (ALT) and the serosa-to-serosa closure (SSC). All closures were immediately completely sealed, with no carbon dioxide (CO(2)) leak detected at 25 cm of water pressure. After recovery from anesthesia, all the animals resumed feeding and returned to preprocedure activities on the same day as the procedure. The animals were monitored daily for signs of peritonitis and sepsis. Preplanned euthanasia of the animals was performed after 7 to 14 days. The peritoneal cavity was studied at necropsy for evidence of wound dehiscence, abscess formation, and gross adhesions.

MAIN OUTCOME MEASUREMENTS

Full-thickness healing of the gastric-wall incisions without intraperitoneal complications on postmortem examination.

RESULTS

All animals survived without complications. Transgastric closure was successful in all the animals by using both study techniques (ALT and SSC) and the T-tag closure. The deployment device performed well, and accurate closure was rapid and reproducible.

CONCLUSIONS

This prototype closure device holds promise in solving some of the problems of closure for transluminal access for NOTES. Both the ALT and the SSC technique hold promise for threadless closure and for simplifying endoscopic techniques. The SSC technique holds promise to maintain surgical principles of serosa-to-serosa apposition. Further studies are recommended before in vivo human use.

Endoscopic closure of gastrointestinal leaks

Surgery has been the mainstay of therapy in patients with gastrointestinal perforations. This paradigm started to shift with the development of techniques for endoscopic closure of gastrointestinal perforations. A detailed review of the literature on this subject, along with a commentary on practical aspects in the management of patients with gastrointestinal leaks, is provided here.

Single-port endoscopic cholecystectomy: a bridge between laparoscopic and translumenal endoscopic surgery

BACKGROUND AND OBJECTIVE

The intentional puncture of the normal viscera is likely the most important issue limiting the widespread use of natural orifice translumenal endoscopic surgery (NOTES). We developed a new procedure for cholecystectomy using a flexible endoscope via a single port placed in the abdominal wall without visceral puncture (single-port endoscopic cholecystectomy; SPEC) as a bridge between laparoscopic surgery and NOTES. This study aimed to evaluate the technical feasibility of SPEC.

METHODS

Five pigs were subjected to SPEC. An endoscope was inserted through a 12-mm port placed in the right upper abdomen. After grasping and retracting the gallbladder using a 2-mm retractor that was directly introduced into the peritoneal cavity, gallbladder excision with ligation of the cystic artery and duct using endoclips was carried out.

RESULTS

A complete gallbladder excision was carried out easily and safely in all cases. No major adverse events occurred. The mean operating time was 67 min (range 52-84 min).

CONCLUSIONS

SPEC is a technically feasible procedure. It is simpler, easier, and safer than NOTES cholecystectomy. SPEC could be a less invasive alternative to the conventional four-port laparoscopic cholecystectomy.

NOTES: approach to the liver and spleen

BACKGROUND

Minimally invasive abdominal surgery means minimal trauma to the abdominal wall, thus reducing postoperative pain and wound complications, and facilitating earlier mobilization and shorter hospitalization in comparison with conventional surgery. Natural orifice translumenal endoscopic surgery (NOTES) has the potential to further reduce the invasiveness of surgery in human patients. Here we report an experimental study of NOTES to access the liver and spleen, discuss its current status, and review the related literature.

METHODS

The utility of transgastric peritoneoscopy was evaluated using one 15-kg pig and four 8-kg dogs on the basis of acute experiments. Under general anesthesia with endotracheal intubation, a forward-viewing, double-channel endoscope was advanced into the peritoneal cavity through a gastric hole. Liver biopsy from the edge of the liver was performed using routine biopsy forceps. Splenectomy was performed using a laparoscopically assisted procedure, and then the spleen was pulled into the stomach using an endoscopic polypectomy snare after enlargement of the gastric orifice. The animals were then sacrificed and necropsy was performed.

RESULTS

There were no complications during incision of the gastric wall and entry into the peritoneal cavity. Peritoneoscopy gave satisfactory visualization of the abdominal cavity in all directions. Liver biopsy was performed successfully without any bleeding and adequate samples were obtained in all cases. Splenectomies were also accomplished uneventfully, except for injury of the splenic parenchyma due to excessive force during pulling into the stomach. Necropsy revealed no particular damage to other intraperitoneal organs related to this transgastric procedure.

CONCLUSION

Although NOTES is a feasible procedure and offers several advantages to patients, surgeons and endoscopists need to resolve several key issues before its clinical introduction for routine surgical work and to establish a training system for NOTES in order to avoid critical complications.

Pure 'natural orifice transluminal endoscopic surgery' for transvaginal nephrectomy in the porcine model

OBJECTIVES

To determine the technical feasibility and reproducibility of pure natural orifice transluminal endoscopic surgery (NOTES) transvaginal nephrectomy using NOTES-specific instrumentation, with no transabdominal assistance.

MATERIALS AND METHODS

Five female farm pigs (mean weight 45 kg) had a right NOTES nephrectomy, using a single-channel gastroscope in the first three pigs and a dual-channel gastroscope in the remaining two. The peritoneal cavity was accessed through the posterior fornix of the vagina. Dissection was started at the lower pole of the kidney, and the ureter was retracted laterally and followed towards the hilum. An XL articulated 60 cm endo-GIA stapler (US Surgical, Norwalk, CO, USA), inserted transvaginally via a separate vaginal incision, was used for tissue retraction and renal hilar transection. The kidney was freed, entrapped in an impermeable sac, and extracted intact transvaginally.

RESULTS

All five procedures were successful with no addition of a transabdominal laparoscopic port or open conversion. The total operative duration decreased from 200 min in the first pig to 60 min in the last (mean 113 min); the mean blood loss was <50 mL, the mean kidney length was 13.9 cm and the weight was 142 g. There were no intraoperative complications; at autopsy, there was no pelvic or bowel injury.

CONCLUSIONS

Pure NOTES transvaginal nephrectomy is feasible in the porcine model. It has the potential of a less morbid approach, providing truly scar-less surgery. Further development of instrumentation is necessary.