During endoscopic submucosal dissection (ESD) for gastric lesions with fibrosis, appropriate traction could provide clear submucosal dissection visualization to improve safety and efficiency of procedures. Therefore, the aim of this study was to evaluate the feasibility of magnetic ring-assisted ESD (MRA-ESD) for gastric fibrotic lesions.

In the eight healthy beagles, 2-3 mL of 50% glucose solution was injected into submucosal layer of the stomach to induce gastric fibrotic lesions. A week after submucosal injection, two endoscopists at different levels performed MRA-ESD or standard ESD (S-ESD) for gastric simulated lesions, respectively. The magnetic traction system consisted of external handheld magnet and internal magnetic ring. The feasibility and procedure outcomes of the magnetic traction system were mainly evaluated.

Forty-eight gastric simulated lesions with ulceration were confirmed to have submucosal fibrosis formation by preoperative endoscopic ultrasonography. The magnetic traction system could be easily established, only took 1.57 min, and allowed excellent submucosal visualization. The total procedure time was significantly shorter in the MRA-ESD group than in the S-ESD group for both endoscopists (mean: 46.83 vs. 25.09 min, p < 0.001), and this difference was accentuated in non-skilled endoscopist. There was significant difference between two groups in bleeding and perforation rates. Histological analysis showed the depth of resected specimens was a little deeper around the fibrotic portion in the S-ESD group (p < 0.001).

The magnetic ring-assisted ESD technique may be an effective and safe treatment for gastric fibrotic lesions and may shorten the endoscopic learning curve for non-skilled endoscopists.

Background: The use of magnetic devices in digestive surgery has been a matter of debate in recent years. The aim of this review was to describe the physical bases, indications, and results of the use of magnets in digestive surgery. Methods: A review of the literature was performed using Scopus, PubMed, ScienceDirect, and SciELO databases considering as inclusion criteria all articles published since 2007 to date, describing the physical basis of magnetic assisted surgery and those that describe the surgical procedure, including case reports, as well as, articles on humans and experimental animals. Results: Sixty-four studies were included, 15 detailing aspects on the physical basis and 49 about indications and results. Magnets are currently used to perform fixed traction, mobilizing structures, and anastomosis in humans and experimental animals. Conclusions: The use of magnets in digestive surgery has shown good results, and no complications arising from their use have been reported. However, more prospective and randomized studies that compare magnetic surgery and conventional techniques are needed.

Introduction: Laparoscopic cholecystectomy (LC) is the gold standard performed by the majority of surgeons worldwide, and the use of single-port cholecystectomy remains a matter of debate. Single-port magnetic-assisted cholecystectomy (SPMAC) was described as an alternative because of its ability for proper triangulation and the advantage of reducing port surgery. The objective of this study is to describe the initial experience of SPMAC and evaluate the surgical learning curve. Materials and Methods: A prospective cohort was conducted between February 2017 and August 2018; 60 patients completed the inclusion criteria. Variables analyzed were gender, age, body mass index, American Society of Anesthesiologist (ASA) classification, operative time, hospital stay, intraoperative bleeding, and conversion rate. Postoperative pain was measured with a visual analogue scale (VAS). Aesthetic perception was measured by the cosmetic visual analogue scale (CVAS). The postoperative complications were graded according to Clavien-Dindo classification, and the cumulative sum (CUSUM) model was used for evaluating the learning curve. Results: The mean operatory time was 56.1 minutes. With regard to the postoperative pain variable, the VAS value was 2 out of 10 in 78.33% of patients. With regard to aesthetic satisfaction, CVAS was reported to be 10 out of 10 in 96.67% of patients. Conversion rate was 0%. The learning curve of operative time was reached at the 22nd patient, according to the CUSUM chart. Conclusions: SPMAC is feasible and effective; in our consideration, an acceptable learning curve considering benign gallbladder pathology is one of the most prevalent in general surgery. Further comparative studies with conventional LC and SPMAC need to be performed to conduct a proper comparison.

Introduction: Recently, magnetic solutions have been proposed to minimize surgical invasiveness. These are comprised of deployable instruments containing magnets which are inserted into the abdominal cavity through a single access point. The manipulation of the internal elements occurs via magnets held on the external surface of the abdominal wall. This technology relies on the magnetic force between the magnets, which is inversely related to the abdominal wall thickness (AWT). The aim of this study was to establish the expected change in AWT from before and after initiation of pneumoperitoneum. Material and methods: Patients scheduled for laparoscopic procedures were assessed by ultrasound for AWT immediately before and during laparoscopy. Change of AWT during laparoscopy was calculated. Statistical analysis was performed using Student's t-test. Results: Thirty-two patients undergoing various laparoscopic procedures were included. Twenty patients were male (62.5%) and ten were morbidly obese (31%). Mean age was 51 years (range 18-76) and average BMI was 28.1 kg/m2 (range 19.0-41.0). AWT decreased on average by 15.6% once pneumoperitoneum was initiated in both obese and non-obese patients (p = .01). Conclusion: Our data suggest that following preoperative assessment of AWT with abdominal wall ultrasound, more patients than expected might be candidates for the use of trans-abdominal magnetic devices.

In recent years, minimally invasive surgery (MIS) has gained wider acceptance among surgeons. MIS requires high skills for the operators, mainly due to its intrinsic technical limitations. Tissue manipulation and retraction remain the most challenging tasks; more specifically liver, stomach, and intestine are the organs mostly involved in retraction tasks for abdominal procedures. The literature reports an increasing interest toward dedicated solutions for abdominal tissue retraction tasks. To overcome the limitations of commercial systems and research prototypes, the aim of this study is the design, the realization, and the validation of a retraction system that is simple, reliable, easy to use, safe, and broadly compatible with MIS. The proposed retractor has two main components: (1) a soft central part with variable stiffness obtained by exploiting the granular jamming phenomenon for assuring, at the same time, safe introduction into the abdominal cavity and stable retraction and (2) two iron cylinders located at the two extremities of the device for anchoring the retractor to the abdominal wall by using the magnetic attraction force between these components and two external permanent magnets. System design has been performed by deeply investigating granular jamming principle and ferromagnetic properties of iron elements. Ex vivo and in vivo assessment has been carried out with the final aim to identify the most appropriate design of each retractor component and to demonstrate the advantages of using a soft system with variable stiffness during a retraction task.

In order to simplify a percutaneous gastrostomy procedure and avoid the need of endoscopy or imaging methods, a novel percutaneous magnetically guided gastrostomy (PMG) technique was conceived. The aim of the present study is to evaluate the feasibility of a novel PMG technique with no endoscopy or any imaging guidance in a porcine model.

Fourteen crossbred domestic pigs were used for prototype development (cadaveric experiments) and proof-of concept, survival study. The magnetic device was conceived using commercially available rare-earth neodymium-based magnets. The experimental design consisted of developing an internal magnetic gastric tube prototype to be orally inserted and coupled to an external magnet placed on the skin, which facilitated stomach and abdominal wall apposition for blind percutaneous gastrostomy tube placement. Then, a gastrostomy tube was percutaneously and blindly placed.

Twelve procedures were undertaken in animal cadavers and two in live models. The technique chosen consisted of using a magnetic gastric tube prototype using six 1 × 1-cm-ring magnets attached to its end. This device enabled successful magnetic coupling with a large (5 cm in diameter) magnet disc placed on the skin. For gastric tube placement, a direct trocar insertion allowed easier and safer placement of a gastric tube as compared to a needle-guide-wire dilation (Seldinger-based) technique. Gastropexy was added to avoid early gastric tube displacement. This novel PMG technique was feasible in a live model experiment.

A novel magnetically guided percutaneous gastrostomy tube insertion technique without the use of endoscopy or image-guidance was successful in a porcine model. A non-inferiority experimental controlled study comparing this technique to percutaneous endoscopic gastrostomy is needed to confirm its efficacy and safety.

The feasibility of magnetic anchor-guided endoscopic submucosal dissection (MAG-ESD) using a neodymium magnet for gastric lesions has not been clarified. The aim of study was to evaluate the feasibility of MAG-ESD using neodymium magnets while treating gastric lesions.

This prospective trial was conducted at the Yamashita Hospital. MAG-ESD was performed for 50 gastric lesions using an insulated-tip knife. The magnetic anchor consisted of an internal neodymium magnet attached to a hemoclip with 3-0 silk. The external and internal magnets were made from the neodymium magnet. The feasibility of traction using MAG-ESD, en bloc resection rate, complete en bloc resection rate, time required for preparation and attaching the magnetic anchor, procedure time, rate of retrieval of the magnetic anchors, and adverse events were evaluated.

Fifty patients (median lesion size, 20 mm [range, 5-100]) were enrolled. MAG-ESDs were successfully performed for all 50 gastric lesions. Adequate counter-traction was obtained using the external magnet. En bloc resections were achieved and complete en bloc resections confirmed in all cases without adverse events. Attaching the magnetic anchor required a median of 6 minutes (range, 2-14). The median procedure time was 49 minutes (range, 15-301), and the magnetic anchors could be retrieved in all cases.

This study clearly demonstrated the feasibility of this MAG-ESD in the stomach. We hope this procedure will facilitate the resection of difficult lesions. (Clinical trial registration number: UMIN000024100.).

The adequate visualization of the dissection line, inside the submucosal layer, supposes the main challenging issue in ESD. For this reason, several counter traction methods have been developed focused on overcoming this handicap. One of which, Magnetic anchor guided - ESD (MG-ESD) is an attractive alternative. However, the usefulness of this approach has been scarcely assessed and compared with other ESD strategies. Therefore, the aim of this study is to compare three different ESD alternatives in experimental faction.

This was a prospective non-randomized study, in which three different ESD techniques were performed in an ex-vivo gastric porcine model by an endoscopist slight expertise in ESD: conventional ESD, waterjet assisted ESD and MG-ESD. MG-ESD was performed using two different magnets: inner Neodymiun ringed shape magnet attached to the simulated lesions by an endoclip and external electromagnet connected to a Single Output Adjustable 24V/0.3A Power Supply Unit.

Forty-six ESD procedures were performed: 24 conventional ESD, 12 waterjet-assisted ESD and 10 MG-ESD. Average size of the simulated lesions was 33.86 mm. No differences in terms of safety and efficacy were registered between the three approaches. Nevertheless, MG-ESD proved to be faster and more efficient than conventional ESD and water-jet assisted ESD (min per cm ² 10.85 vs. 7.43 vs. 3,41; P  = 0.001).

MG-ESD could be a feasible alternative to conventional ESD even at the beginning of the learning curve. Therefore, researches focused on developing appropriate ESD magnetic devices and further comparative studies must be promoted, in order to assess the reliable usefulness of the magnet-assistance in ESD.

Endoscopic submucosal dissection (ESD) is a well-established, minimally invasive treatment for superficial neoplasms of the gastrointestinal tract. The universal adoption of ESD has been limited by its slow learning curve, long procedure times, and high risk of complications. One technical challenge is the lack of a second hand that can provide traction, as in conventional surgery. Reliable tissue retraction that exposes the submucosal plane of dissection would allow for safer and more efficient dissection. Magnetic anchor guided endoscopic submucosal dissection (MAG-ESD) has potential benefits compared to other current traction methods. MAG-ESD offers dynamic tissue retraction independent of the endoscope mimicking a surgeon's "second hand". Two types of magnets can be used: electromagnets and permanent magnets. In this article we review the MAG-ESD technology, published work and studies of magnets in ESD. We also review the use of magnetic anchor guidance systems in natural orifice transluminal endoscopic surgery and the idea of magnetic non-contact retraction using surface ferromagentization. We discuss the current limitations, the future potential of MAG-ESD and the developments needed for adoption of this technology.

To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.

The system consists of a miniature magnetically anchored camera with a 30° downward angle, an external magnetically anchored unit, and a vision output device. The camera weighs 12 g, measures Φ10.5 mm × 55 mm and has two magnets, a vision model, a light source, and a metal hexagonal nut. To test the prototype, the camera was inserted through a 12-mm conventional trocar in an ex vivo real liver laparoscopic training system. A trocar-less laparoscopic cholecystectomy was performed 6 times using a 12-mm and a 5-mm conventional trocar. In addition, the same procedure was performed in four canine models.

Both procedures were successfully performed using only two conventional laparoscopic trocars. The cholecystectomy was completed without any major complication in 42 min (38-45 min) in vitro and in 50 min (45-53 min) using an animal model. This camera was anchored and controlled by an external unit magnetically anchored on the abdominal wall. The camera could generate excellent image. with no instrument collisions.

The camera system we designed provides excellent optics and can be easily maneuvered. The number of conventional trocars is reduced without adding technical difficulties.

The magnetic anchoring guidance system (MAGS) is one of the most promising technological innovations in minimally invasive surgery and consists in two magnetic elements matched through the abdominal or thoracic wall. The internal magnet can be inserted into the abdominal or chest cavity through a small single incision and then moved into position by manipulating the external component. In addition to a video camera system, the inner magnetic platform can house remotely controlled surgical tools thus reducing instruments fencing, a serious inconvenience of the uniportal access. The latest prototypes are equipped with self-light-emitting diode (LED) illumination and a wireless antenna for signal transmission and device controlling, which allows bypassing the obstacle of wires crossing the field of view (FOV). Despite being originally designed for laparoscopic surgery, the MAGS seems to suit optimally the characteristics of the chest wall and might meet the specific demands of video-assisted thoracic surgery (VATS) surgery in terms of ergonomics, visualization and surgical performance; moreover, it involves less risks for the patients and an improved aesthetic outcome.

Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems.

In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master-slave control strategy was adopted, in which the control model was established by off-line experiments.

The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS.

The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application.

Obesity treatment options are of great interest worldwide with major developments in the past 20 years. From general surgery to natural orifice transluminal endoscopic surgery intervention nowadays, obesity surgical therapies have surely developed and are now offering a variety of possibilities.

Although surgery is the only proven approach for weight loss, a joint decision between the physician and patient is required before proceeding to such a procedure. With a lot of options available, the treatment should be individualized because the benefits of surgical intervention must be weighed against the surgical risks.

Medline search to locate full-text articles and abstracts with obvious conclusions by using the keywords: obesity, surgical endoscopy, gastric bypass, bariatric surgery, and endoscopic surgery, alone and in various combinations. Additional relevant publications were also searched using the reference lists of the identified articles as a starting point.

Laparoscopic Roux-en-Y gastric bypass still is the most effective, less invasive, bariatric surgical intervention, although there are various complications encountered, such as postoperative hemorrhage (1.9%-4.4%), internal hernias, anastomotic strictures (2.9%-23%), marginal ulcerations (1%-16%), fistulas (1.5%-6%), weight gain, and nutritional deficiencies. However, the absence of parietal incisions, less pain, decreased risk of infection, and short hospital stay make room for endoscopic surgery as a possible valid option for obesity for both the doctors' and the patients' perspective.

The current tendency is to promote surgical treatment of obesity to a status of less invasive scars therefore promoting minimally invasive surgical techniques.

The purpose of this work is to design and validate an innovative magnetic-based device for tissue retraction for minimally invasive surgery.

An intra-abdominal magnetic module is coupled with an extracorporeal system for establishing a stable attraction, and consequently a reliable tissue retraction. Once the retractor has been inserted into the abdomen, tissue retraction is not constrained by a fixed access port, thus guaranteeing a more flexible, safer and less invasive operation. The intra-abdominal unit is composed of an axial permanent magnet attached to a stainless-steel non-magnetic alligator clip by a traditional suturing thread. A miniaturized mechanism to adjust the length of the suturing thread for lengthening or shortening the distance between the tissue grasper and the internal magnetic unit is included. A multiphysics approach assured a dedicated design that thoroughly fulfills anatomical, physiological and engineering constraints.

System functionalities were demonstrated both in in-vitro and ex-vivo conditions, reaching good results and promising outcomes in terms of effectiveness and maneuverability. The retractor was successfully tested in an animal model, carrying out a whole retraction procedure.

The proposed retraction system resulted to be intuitive, reliable, robust and easy to use, representing a suitable device for MIS procedures.

Laparoendoscopic single-site surgery and natural orifice transluminal endoscopic surgery attempt to reduce transabdominal port sites. These require all instruments to pass through a single access point, leading to instruments collide or work at unfamiliar angles. Thus, we designed an internal grasper under magnetic anchoring guide system (MAGS) platform and investigated its utility and operability.

We measured the configuration for magnetic force decay over distance using a standardized, ex vivo laboratory testing apparatus. An electronic balance was used to measure the force of the gallbladder pull in ten patients with gallbladder stones. One pig (11 mm abdominal wall thickness) underwent a compressed trial of MAGS platform. The device was left in place for 20 min before tissue sections were harvested, and histologic assessment was performed. The utility and operability were investigated in four pigs (38-280 kg weight).

The magnetic attraction force decayed exponentially over distance; the force of pulling gallbladder was 7.46 ± 0.54 N. This pairing of components allowed for coupling to a theoretical distance of 10 mm. No gross tissue damage was observed. H-E stain showed no necrosis in all specimens. One failed due to wall thickness of 45 mm. Others showed the critical view, triangulation of instruments was obtained, and instrument collision or "sword fighting" was reduced.

The MAGS platform overcomes limitations such as collisions and lack of triangulation, reduces transabdominal port sites, and is easy to operate. However, our internal grasper requires the abdominal wall thickness below 10 mm.

This review looks at the implementation of magnetic-based approaches in surgical instruments for abdominal surgeries. As abdominal surgical techniques advance toward minimizing surgical trauma, surgical instruments are enhanced to support such an objective through the exploration of magnetic-based systems. With this design approach, surgical devices are given the capabilities to be fully inserted intraabdominally to achieve access to all abdominal quadrants, without the conventional rigid link connection with the external unit. The variety of intraabdominal surgical devices are anchored, guided, and actuated by external units, with power and torque transmitted across the abdominal wall through magnetic linkage. This addresses many constraints encountered by conventional laparoscopic tools, such as loss of triangulation, fulcrum effect, and loss/lack of dexterity for surgical tasks. Design requirements of clinical considerations to aid the successful development of magnetic surgical instruments, are also discussed.

Magnetic anchored surgical instruments (MASI), relying on magnetic force, can break through the limitations of the single port approach in dexterity. Individual characteristic abdominal wall thickness (ICAWT) deeply influences magnetic force that determines the safety of MASI. The purpose of this study was to research the abdominal wall characteristics in MASI applied environment to find ICAWT, and then construct an artful method to predict ICAWT, resulting in better safety and feasibility for MASI.

For MASI, ICAWT is referred to the thickness of thickest point in the applied environment. We determined ICAWT through finding the thickest point in computed tomography scans. We also investigated the traits of abdominal wall thickness to discover the factor that can be used to predict ICAWT.

Abdominal wall at C point in the middle third lumbar vertebra plane (L3) is the thickest during chosen points. Fat layer thickness plays a more important role in abdominal wall thickness than muscle layer thickness. "BMI-ICAWT" curve was obtained based on abdominal wall thickness of C point in L3 plane, and the expression was as follow: f(x) = P1 × x 2 + P2 × x + P3, where P1 = 0.03916 (0.01776, 0.06056), P2 = 1.098 (0.03197, 2.164), P3 = -18.52 (-31.64, -5.412), R-square: 0.99.

Abdominal wall thickness of C point at L3 could be regarded as ICAWT. BMI could be a reliable predictor of ICAWT. In the light of "BMI-ICAWT" curve, we may conveniently predict ICAWT by BMI, resulting a better safety and feasibility for MASI.

Magnetic anchor-guided endoscopic submucosal dissection (MAG-ESD) was developed to reduce adverse events such as bleeding and perforation and to facilitate ESD. However, the external electromagnet required miniaturization to make it suitable for daily clinical practice.

To evaluate the feasibility of simplified MAG-ESD using permanent magnets.

Case series.

Nagoya University Hospital.

Beagle dogs.

The simplified MAG-ESD was performed on 10 representative areas of the stomachs of beagle dogs. The magnetic anchor consisted of an internal magnet attached to a hemoclip. The external and internal magnets were made from the rare earth neodymium.

The feasibility of countertraction with good visualization using simplified MAG-ESD. The rate of perforation, the time required for preparation, and attaching the magnetic anchor were also evaluated.

All lesions were successfully resected without perforation. The magnetic anchor could be controlled easily, and direct visualization was maintained by adequate counter traction. Preparing the magnetic anchor and grasping the mucosal edge using the hemoclip was easy and required a median of only 4 minutes (range, 2-7 minutes).

Animal experiment, low number and lesion size.

This simplified MAG-ESD is feasible and allowed excellent visualization in the dog stomach. The feasibility of this system should be assessed in humans.

In an open surgery, identification of precise margins for curative tissue resection is performed by manual palpation. This is not the case for minimally invasive and robotic procedures, where tactile feedback is either distorted or not available. In this paper, we introduce the concept of intraoperative wireless tissue palpation. The wireless palpation probe (WPP) is a cylindrical device (15 mm in diameter, 60 mm in length) that can be deployed through a trocar incision and directly controlled by the surgeon to create a volumetric stiffness distribution map of the region of interest. This map can then be used to guide the tissue resection to minimize healthy tissue loss. The wireless operation prevents the need for a dedicated port and reduces the chance of instrument clashing in the operating field. The WPP is able to measure in real time the indentation pressure with a sensitivity of 34 Pa, the indentation depth with an accuracy of 0.68 mm, and the probe position with a maximum error of 11.3 mm in a tridimensional workspace. The WPP was assessed on the benchtop in detecting the local stiffness of two different silicone tissue simulators (elastic modulus ranging from 45 to 220 kPa), showing a maximum relative error below 5%. Then, in vivo trials were aimed to identify an agar-gel lump injected into a porcine liver and to assess the device usability within the frame of a laparoscopic procedure. The stiffness map created intraoperatively by the WPP was compared with a map generated ex vivo by a standard uniaxial material tester, showing less than 8% local stiffness error at the site of the lump.

Laparoscopic surgery has displaced open surgery as the standard of care for many clinical conditions. NOTES has been described as the next surgical frontier with the objective of incision-free abdominal surgery. The principal challenge of NOTES procedures is the loss of triangulation and instrument rigidity, which is one of the fundamental concepts of laparoscopic surgery. To overcome these problems necessitates the development of new instrumentation. material and methods: We aimed to assess the use of a very simple combination of internal and external magnets that might allow the vigorous multiaxial traction/counter-traction required in NOTES procedures. The magnet retraction system consisted of an external magnetic assembly and either small internal magnets attached by endoscopic clips to the designated tissue (magnet-clip-approach) or an endoscopic grasping forceps in a magnetic deflector roll (magnet-trocar-approach).

We compared both methods regarding precision, time and efficacy by performing transgastric partial uterus resections with better results for the magnet-trocar-approach.

This proof-of-principle animal study showed that the combination of external and internal magnets generates sufficient coupling forces at clinically relevant abdominal wall thicknesses, making them suitable for use and evaluation in NOTES procedures, and provides the vigorous multiaxial traction/counter-traction required by the lack of additional abdominal trocars.

This study evaluated operative outcomes and workload during single-site laparoscopy (SSL) using a magnetically anchored cautery dissector (MAGS) compared with a conventional laparoscopic hook cautery (LAP).

Each cautery was used to perform six SSL porcine cholecystectomies. For MAGS, the cautery device was inserted through the umbilical incision, magnetically coupled, and deployed; two graspers and a laparoscope were used. For LAP, two percutaneous retraction sutures, one grasper, a hook cautery dissector, and a laparoscope were used. Operative outcomes, surgeon ratings (scale, 1-5; 1 = superior), and workload (scale, 1-10; 1 = superior) were evaluated.

No significant differences were detected for operative outcomes and surgeon ratings, however, trends were detected favoring MAGS. Surgeon workload ratings were significantly better for MAGS (2.6 ± 0.2) vs. LAP (5.6 ± 1.1; p < 0.05). For MAGS, depth perception and triangulation were excellent and the safe handling protocol was followed with no complications. For LAP, the parallelism of instruments and lack of triangulation hindered depth perception, caused instrument conflicts, and resulted in two minor complications (one superficial liver laceration and one inadvertent burn to the diaphragm).

These data suggest that using the MAGS device for SSL cholecystectomy results in equivalent (or better) operative outcomes and less workload compared with LAP.

We report a redesigned magnetically anchored and guided systems (MAGS) camera with improved optics and a 30° downward viewing angle that facilitates solitary surgeon laparo-endoscopic single site (LESS) nephrectomy.

The prototype consists of an external 2 by 6 cm cylinder containing magnets positioned such that the intra-abdominal camera is anchored on the peritoneal surface with a default 30° downward angle. It was inserted through a 3 cm LESS-port periumbilical incision in three pigs (mean 47 kg). The camera was coupled with the handheld magnetic device across the anterior abdominal wall and was steered into position to view the kidney. LESS nephrectomy was then performed.

Since a standard LESS laparoscope was not needed, only the two operative instruments were inserted through the single incision port, significantly decreasing instrument "clashing" compared with traditional LESS nephrectomy. Due to the favorable angle of view of the camera and its self-anchoring capability, no assistant was needed to drive the camera. Instead, the surgeon periodically made minor adjustments to optimize the view. The nephrectomy was completed without complication in an average of 35 minutes in these three nonsurvival animals.

The MAGS camera provides good optics and easy maneuverability during LESS porcine nephrectomy. As with other MAGS instruments, by replacing a traditional transabdominal laparoscope that occupies access port space, use of this insertable camera may diminish some of the "collision challenge" of LESS surgery. Also, by being self-anchoring, this prototype may minimize the need for an assistant surgeon.

The purpose of this study was to evaluate the histological effects of dynamic abdominal wall compression using the magnetic anchoring and guidance system (MAGS) platform.

Cholecystectomy was performed in two nonsurvival and two survival pigs using a single-site laparoscopic (SSL) approach. A deployable MAGS cautery dissector was used to perform the entire dissection in conjunction with a laparoscope and other instruments. The abdominal wall areas corresponding to the region occupied by the MAGS platform were examined grossly and microscopically for signs of tissue damage. Gallbladder dissection time was 36 min with no complications. Compressed abdominal wall thickness was 1.4 cm.

In all four animals, a very mild skin erythema was noted immediately postprocedure but was nonvisible within 20 min. Mild peritoneal blanching was noted in two animals, and one animal exhibited a 5-mm area of petechiae. Necropsy demonstrated no adhesions. Light microscopy documented no evidence of tissue injury for all specimens.

This study demonstrated that the use of the MAGS cautery dissector for a SSL cholecystectomy was advantageous in providing triangulation and did not result in any significant gross or microscopic tissue damage despite the thin abdominal wall of the porcine model.

The clinical application of natural orifice transluminal endoscopic surgery (NOTES) for sigmoidectomy is associated with several difficulties that need to be overcome before wider clinical application of the procedure. The purpose of this study was to evaluate the technical feasibility and safety of transgastric sigmoidectomy in a survival animal model, as well as to evaluate the safety and usability of a custom paired magnetic intraluminal device, which we developed for the NOTES procedure.

Survival experiments were conducted on 24-33-kg dogs. After anesthesia, a gastrotomy was created using double-channel endoscope, and peritoneoscopy was performed. The sigmoid colon was retracted laterally using paired magnetic intraluminal device, the mesocolon was dissected, and the branch vessel was sealed. The anvil was placed into the descending colon through anus. A proximal and distal colonic transection was then performed. The circular stapler was passed through the anus and performed end-to-end anastomosis. Afterwards the specimen was removed through gastrotomy, and the gastric incision was closed. Postoperatively, all dogs were recovered and monitored for well-being during convalescence. Reexploration was practiced under anesthesia 2 weeks after surgery for evaluation of intra-abdominal complications, and intra-peritoneal cultures for microorganism.

The mean operative time was 141 (range, 122-157) min. There were no complications or physical evidence of sepsis or bowel obstruction during the observation period. Only one dog exhibited decreased body weight, decreasing to 20.4 kg from 22.4 kg after surgery; all of the other dogs exhibited increased body weight. We observed no evidence of peritonitis, intra-abdominal abscess, bleeding, or organ injury on reexploration conducted on day 14 after surgery.

Transgastric NOTES sigmoidectomy is a safe operation technique as evaluated in a dog model. The paired magnetic intraluminal device that was used in this study was useful to avoid an abdominal incision for retracting the sigmoid colon.