Mid-term patency after magnetic coupling for distal bypass anastomosis in coronary surgery

Comparative study of cylindrical vs circular ring magnets for colonic anastomosis in rats

BACKGROUND

Magnetic compression anastomosis (MCA) offers a simple and reliable technique for inducing anastomoses at any point along the digestive tract. Evidence regarding whether the design of the MCA device influences the anastomosis effect is lacking.

AIM

To investigate any difference in the side-to-side colonic anastomosis effect achieved with cylindrical vs circular ring magnets.

METHODS

We designed cylindrical and circular ring magnets suitable for side-to-side colonic anastomosis in rats. Thirty Sprague-Dawley rats were randomly divided into a cylindrical group, circular ring group, and cylindrical–circular ring group (n = 10/group). Side-to-side colonic anastomosis was completed by transanal insertion of the magnets without incision of the colon. Operation time, perioperative complications, and magnet discharge time were recorded. Rats were euthanized 4 weeks post-operatively, and anastomotic specimens were obtained. The burst pressure and anastomotic diameter were measured sequentially, and anastomosis formation was observed by naked eye. Histological results were observed by light microscopy.

RESULTS

In all 30 rats, side-to-side colonic anastomosis was completed, for an operation success rate of 100%. No postoperative complications of bleeding and intestinal obstruction occurred, and the postoperative survival rate were 100%. The operation time, magnet discharge time, anastomotic bursting pressure, and anastomotic diameter did not differ significantly among the three designs (P > 0.05). Healing was similar across the groups, with gross specimens showing good anastomotic healing and good mucosal continuity observed on histological analysis.

CONCLUSION

This study found no significant difference in the establishment of rat side-to-side colonic anastomosis with the use of cylindrical vs circular ring magnets.

Sutureless vascular anastomotic approaches and their potential impacts

Sutureless anastomotic devices present several advantages over traditional suture anastomosis, including expanded global access to microvascular surgery, shorter operation and ischemic times, and reduced costs. However, their adaptation for arterial use remains a challenge. This review aims to provide a comprehensive overview of sutureless anastomotic approaches that are either FDA-approved or under investigation. These approaches include extraluminal couplers, intraluminal devices, and methods assisted by lasers or vacuums, with a particular emphasis on tissue adhesives. We analyze these devices for artery compatibility, material composition, potential for intimal damage, risks of thrombosis and restenosis, and complications arising from their deployment and maintenance. Additionally, we discuss the challenges faced in the development and clinical application of sutureless anastomotic techniques. Ideally, a sutureless anastomotic device or technique should eliminate the need for vessel eversion, mitigate thrombosis through either biodegradation or the release of antithrombotic drugs, and be easily deployable for broad use. The transformative potential of sutureless anastomotic approaches in microvascular surgery highlights the necessity for ongoing innovation to expand their applications and maximize their benefits.

Treatment of anastomotic stricture after rectal cancer operation by magnetic compression technique: A case report

BACKGROUND

The treatment of postoperative anastomotic stenosis (AS) after resection of colorectal cancer is challenging. Endoscopic balloon dilation is used to treat stenosis in such cases, but some patients do not show improvement even after multiple balloon dilations. Magnetic compression technique (MCT) has been used for gastrointestinal anastomosis, but its use for the treatment of postoperative AS after colorectal cancer surgery has rarely been reported.

CASE SUMMARY

We report a 72-year-old man who underwent radical resection of colorectal cancer and ileostomy one year ago. An ileostomy closure was prepared six months ago, but colonoscopy revealed a narrowing of the rectal anastomosis. Endoscopic balloon dilation was performed three times, but colonoscopy showed no significant improvement in stenosis. The AS was successfully treated using MCT.

CONCLUSION

MCT is a minimally invasive method that can be used for the treatment of postoperative AS after colorectal cancer surgery.

Influence of different magnetic forces on the effect of colonic anastomosis in rats

BACKGROUND

Despite much work having been conducted on magnetic compression anastomosis (MCA) in the digestive tract, there are no reports on the influence of magnetic force on the anastomosis.

AIM

To investigate the effect of different magnetic force magnets on the MCA of the digestive tract.

METHODS

Two groups of magnets of the same sizes but different magnetic forces were designed and produced. A total of 24 Sprague-Dawley rats were randomly assigned into two groups (powerful magnet group and common magnet group), with 12 rats in each group. Two types of magnets were used to complete the colonic side-to-side anastomosis of the rats. The operation time and magnet discharge time were recorded. The anastomotic specimens were obtained 4 wk after the operation and then the burst pressure and diameter of the anastomosis were measured, and the anastomosis was observed via the naked eye and subjected to histological examination.

RESULTS

The magnetic forces of the powerful and common magnet groups at zero distance were 8.26 N and 4.10 N, respectively. The colonic side-to-side anastomosis was completed in all 24 rats, and the operation success rate and postoperative survival rate were 100%. No significant difference was noted in the operation time between the two groups. The magnet discharge time of the powerful magnet group was slightly longer than that of the common magnet group, but the difference was not statistically significant (P = 0.513). Furthermore, there was no statistical difference in the burst pressure (P = 0.266) or diameter of magnetic anastomosis (P = 0.095) between the two groups. The gross specimens of the two groups showed good anastomotic healing, and histological observation indicated good mucosal continuity without differences on healing.

CONCLUSION

In the rat colonic side-to-side MCA model, both the powerful magnet with 8.26 N and the common magnet with 4.10 N showed no significant impact on the anastomosis establishment process or its effect.

Magnetic compression anastomosis for reconstruction of digestive tract after total gastrectomy in beagle model

BACKGROUND

Magnetic compression anastomosis (MCA) is a simple procedure contributing to a reliable anastomosis. However, digestive-tract reconstruction after total gastrectomy using MCA has not yet been reported.

AIM

To investigate the feasibility of MCA for simultaneous esophagojejunostomy and jejunojejunostomy after total gastrectomy using beagle dogs.

METHODS

Sixteen beagles were randomly divided into an MCA group (study group, n = 8) and a manual-suture anastomosis group (control group, n = 8). Two different magnetic anastomosis devices were used in the study group for esophagojejunal and jejunojejunal anastomoses. Both devices included a pair of circular daughter and parent magnets each. The time of esophagojejunostomy and jejunojejunostomy, postoperative complications, and survival rate of the two groups were compared. The dogs were sacrificed one month after the operation and their anastomotic specimens were obtained. Healing was observed by the naked eye and a light microscope.

RESULTS

Digestive-tract reconstruction after total gastrectomy was successfully completed in both groups (survival rate = 100%). In the study group, esophagojejunal and jejunojejunal anastomoses took 6.13 ± 0.58 and 4.06 ± 0.42 min, respectively, significantly lower than those in the control group (15.63 ± 1.53 min, P < 0.001 and 10.31 ± 1.07 min, P < 0.001, respectively). Complications such as bleeding, anastomotic leakage, and anastomotic stenosis were not observed. In the study group, the magnets did not interfere with each other. Discharge time of the jejunojejunal magnetic anastomosis device was 10.75 ± 1.28 d, while that of the esophagojejunal magnetic anastomosis device was 12.25 ± 1.49 d. Residual silk was found in the control group. The study group showed a greater smoothness of the anastomosis than that of the control group. All layers of anastomosis healed well in both groups.

CONCLUSION

MCA is a safe and feasible procedure for digestive-tract reconstruction after total gastrectomy in this animal model.

The Evolving Use of Magnets in Surgery: Biomedical Considerations and a Review of Their Current Applications

The novel use of magnetic force to optimize modern surgical techniques originated in the 1970s. Since then, magnets have been utilized as an adjunct or alternative to a wide array of existing surgical procedures, ranging from gastrointestinal to vascular surgery. As the use of magnets in surgery continues to grow, the body of knowledge on magnetic surgical devices from preclinical development to clinical implementation has expanded significantly; however, the current magnetic surgical devices can be organized based on their core function: serving as a guidance system, creating a new connection, recreating a physiologic function, or utilization of an internal–external paired magnet system. The purpose of this article is to discuss the biomedical considerations during magnetic device development and review the current surgical applications of magnetic devices.

Sutureless versus Hand-Sewn Coronary Anastomoses: A Systematic Review and Meta-Analysis

BACKGROUND

Sutureless coronary anastomotic devices are intended to facilitate minimally invasive coronary artery bypass grafting (MICS-CABG) by easing and eventually standardizing the anastomotic technique. Within this systematic review and meta-analysis, we aim to determine patency and to evaluate safety outcomes for the sutureless anastomoses.

METHODS

CENTRAL, MEDLINE, and EMBASE were searched from database start till August 2021 in a predefined search strategy combining the key concepts: 'coronary artery bypass grafting', 'sutureless coronary anastomoses', and 'hand-sewn coronary anastomoses' by the Boolean operation 'AND'. Study characteristics, patient demographics, interventional details, and all available outcome data were extracted. A meta-analysis was performed on patency at longest follow-up. Safety outcomes were presented.

RESULTS

A total of eleven trials towards six sutureless anastomotic devices were included, comprising 3724 patients (490 sutureless and 3234 hand-sewn). There was no significant difference in patency at a mean follow-up duration of 546.3 (range 1.5-2691) days, with a risk ratio of 0.77 (95% CI 0.55-1.06). MACE was reported in 4.5% sutureless and 3.9% hand-sewn patients, including all-cause mortality (resp. 1.3 vs. 1.9%), myocardial infarction (resp. 1.6 vs. 1.7%), and coronary revascularization (resp. 1.8 vs. 0.5%). Incomplete hemostasis occurred in 24.8% of the sutureless anastomoses. Intra-operative device failure forced conversion to hand-sewn or redo-anastomosis in 5.8% of the sutureless cases.

CONCLUSION

Based on the systematic review and meta-analysis including six devices, we conclude that sutureless coronary anastomotic devices appear safe and effective when used by well-trained and dedicated surgical teams.

Constant magnetic field in treating congenital esophageal and anorectal malformation: a review

Background

Congenital esophageal and anorectal malformation are common in neonates. Refractory esophageal anastomotic stricture and abnormal defecation after surgical correction in infants are challenging surgical problems. Magnetic compression anastomosis (MCA) using mated magnets with their interposed compressed tissue may result in serosa-to-serosa apposition.

Data sources

A literature search was performed to establish an algorithm for these accidents by the authors to identify relevant articles published from 1977 to 2019 in Google, Medline, ISI Web of Knowledge Ovid, CNKI and library document delivery, using search terms “magnetics”, “esophageal malformation”, “anorectal” and “perforation”. A total of 24 literatures were collected.

Results

Magnamosis is technically feasible for alimentary tract anastomoses in pediatric patients. The magnets are most commonly made of neodymium–iron–boron and samarium–cobalt alloys, which have been employed to create solid anastomosis for long-gap esophageal atresia and refractory esophageal stricture without thoracotomy in children in recent years. Furthermore, magnamosis can be used for the functional undiversion of ileostomy. In anorectal malformations with favorable anatomy, this procedure may avoid an operative repair such as posterior sagittal reconstruction.

Conclusion

Translumenal anastomosis of digestive tract using the MCA is a reliable, minimally invasive and feasible method to treat congenital esophageal and anorectal malformation.

Magnetic Anastomosis Rings to Create Portacaval Shunt in a Canine Model of Portal Hypertension

PURPOSE

This study evaluated a novel magnetic compression technique (magnamosis) for creating a portacaval shunt in a canine model of portal hypertension, relative to traditional manual suture.

METHODS

Portal hypertension was induced in 18 dogs by partial ligation of the portal vein (baseline). Six weeks later, extrahepatic portacaval shunt implantation was performed with either magnetic anastomosis rings, or traditional manual suture (n = 9, each). The two groups were compared for operative time, portal vein pressure, and serum biochemical indices. Twenty-four weeks post-implantation, the established anastomoses were evaluated by color Doppler imaging, venography, and gross and microscopic histological examinations.

RESULTS

Anastomotic leakage did not occur in either group. The operative time to complete the anastomosis for magnamosis (4.12 ± 1.04 min) was significantly less than that needed for manual suture (24.47 ± 4.89 min, P < 0.01). The portal vein pressure in the magnamosis group was more stable than that in the manual suture group. The blood ammonia level at the end of the 24-week post-implantation observation period was significantly lower in the magnamosis group than in the manual suture group. Gross and microscopic histological examinations revealed that better smoothness and continuity of the vascular intima had been achieved via magnamosis than with manual suture.

CONCLUSION

Magnamosis was superior to manual suture for the creation of a portacaval shunt in this canine model of portal hypertension.

Biomechanical and Performance Evaluation of Magnetic Elliptical-Ring Compressive Anastomoses

BACKGROUND

After magnetic compressive anastomosis, anastomat passage through the narrow channels of the digestive tract is difficult owing to the device's large volume. Such passage can lead to mechanical damage to the digestive tract or anastomat's unstable excretion time. This article presents a new magnetic compressive anastomotic approach.

METHODS

A magnetic elliptical-ring compressive anastomat was designed and evaluated for placement and passage in vitro. Nine young adult dogs underwent laparotomy with intestinal tissue side-to-side anastomosis. Four different groups of magnetic compressive anastomats of two different magnetic force levels (20 N or 30 N) and shapes (round or elliptical) were implanted into each dog simultaneously. Three dogs were euthanized on each of postoperative day 1, day 4, and day 7. Anastomoses were then compared with respect to histology and tensile fracture force.

RESULTS

The magnetic elliptical-ring compressive anastomat was functional but produced less obstruction compared to its round counterpart during passage through the esophagus and intestine. Nine dogs underwent successful surgery and harvesting of 30 total anastomoses. Histology of anastomotic tissue showed that, along the newly formed tunnel connecting the two sides of anastomotic tissues, compressed tissues became thinner and fell off, and initial anastomoses formed on the seventh postoperative day. There were large differences in tensile fracture force among the anastomoses formed by magnets with different magnetic forces of the same structure. However, the magnetic compressive anastomat structure did not affect anastomotic repair during magnetic compression anastomosis.

CONCLUSIONS

The magnetic elliptical-ring compressive anastomat is an efficient anastomotic device that can be used easily and with good passage. The device has good biomechanical properties and can be used with endoscopy to reduce operative time.

Laparoscopic Magnetic Compression Biliojejunostomy: A Preliminary Clinical Study

BACKGROUND

Magnetic compression anastomosis is a feasible and effective method for bilioenteric anastomosis (BEA) in animal model. The objective of the present study was to report our initial clinical experience in laparoscopically magnetic compression bilioenteric anastomosis (LMC-BEA).

METHODS

Patients with obstructive jaundice who were candidates for LMC-BEA were prospectively enrolled from 2013 to 2015. All the procedures were performed laparoscopically. A mother magnet and drainage tube were placed in the proximal bile duct and tightened by a purse suture after dissection of the common bile duct. The drainage tube was introduced into the jejunal lumen at the anastomotic site and guided a daughter magnet to approximate the mother magnet. The two magnets mated at the anastomotic site. All the patients were routinely followed up for magnets discharge till the end of the study.

RESULTS

In total, four patients with malignant obstructive jaundice and one patient with benign biliary stricture were included. The median age was 70 y (range, 49-74 y). The median time for LMC-BEA was 12 min (range, 8-15 min). A complete anastomosis was confirmed after a median time of 21 d (range, 5-25 d) postoperatively by cholangiography via drainage tube. The magnets were expulsed around 41 d after surgery (range, 12-47 d) postoperatively. With a median follow-up of 313 d (range, 223-1042 d), no complications associated with magnetic anastomosis was documented, such as bile leakage or anastomotic stricture.

CONCLUSIONS

Magnetic compression is a promising alternate method for laparoscopic BEA. Among the five patients undergoing LMC-BEA, no one developed anastomotic complications.

Magnamosis combined with endoscopy: A new endoscopic technique in digestive surgery

Conventional hand-sewn technique is the basic method for anastomosis in the gastrointestinal tract. However, with the rapid development of minimally invasive surgery and the spread of fast track surgery, hand-sewn technique cannot satisfy the requirements of modern surgery. The common goal that the majority of surgeons seek to achieve has changed: to reduce surgical invasion and operative time as minimally as possible, on the premise that therapeutic and anastomotic effects can be guaranteed. Therefore, after more than 30 years of exploration and development, magnamosis as a novel anastomosis technique shows its significant superiority in anastomosis or recanalization in the gastrointestinal tract. Furthermore, the combination of magnamosis and endoscopy may transform part of the surgical procedures into endoscopic procedures. This review aims to elucidate the application and future development of magnamosis combined with endoscopy in anastomosis or recanalization in the gastrointestinal tract.

Compression anastomoses in colorectal surgery: a review

The main serious risks of anastomotic construction in the colon and rectum include dehiscence and stricture formation. There is a resurgence of interest in sutureless anastomoses formed by compression elements since the introduction of shape memory alloy (SMA) systems, which evoke minimal early inflammatory response whilst maintaining anastomotic integrity. Currently, the most commonly used SMA is the nickel-titanium (NiTi) alloy that is highly biocompatible, returning to its pre-deformed stable (austenite) shape under different mechanical and thermal loads for use in humans. Pre-clinical data for shape memory alloy systems in colorectal anastomoses are limited, but it appears to be safe in porcine and canine models with limited leakage and reduced stricture formation. There does not appear to be any difference in tissue biochemistry of inflammatory markers when compared with conventional stapled techniques, although the few studies available show a markedly reduced early inflammatory response at the anastomotic site with the NiTi device. The majority of the clinical data concerning compression anastomoses are derived from the biofragmentable anastomotic ring device. This device has fallen out of use because of reported leaks, instrumental failure and problems with device expulsion. A novel SMA device, the NiTi anastomotic ring, permits construction of a low rectal anastomosis construction during open or laparoscopic procedures. The preliminary data demonstrate a safety comparable to conventional staple technology. This device also provides the potential of benefit of reduced anastomotic inflammation, because the compression ring results in direct serosa-to-serosa (or alternatively serosa-to-muscularis propria) apposition without the persistence of residual foreign material. This type of construction could lead to a reduced incidence of early anastomotic leakage and/or the development of anastomotic stenosis. Randomized clinical trials employing a NiTi arm for elective, emergency and high-risk colorectal anastomoses are required to determine its indications and clinical profile as well as to assess whether such technology may selectively obviate the need for proximal diversion in low colorectal anastomoses.

Creation of transcatheter aortopulmonary and cavopulmonary shunts using magnetic catheters: feasibility study in swine

Surgical shunts are the basic form of palliation for many types of congenital heart disease. The Glenn shunt (superior cavopulmonary connection) and central shunt (aortopulmonary connection) represent surgical interventions that could potentially be accomplished by transcatheter techniques. We sought to investigate the efficacy of using neodymium iron boron (NdFeB) magnetic catheters to create transcatheter cavopulmonary and aortopulmonary shunts. NdFeB magnets were machined and integrated into catheters. "Target" catheters were placed in the pulmonary arteries (PAs), and radiofrequency "perforation" catheters were placed in either the descending aorta (DAo) for central shunts or the superior vena cava (SVC) for Glenn shunts. The magnet technique or "balloon target" method was used to pass wires from the DAo or the SVC into the PA. Aortopulmonary and cavopulmonary connections were then created using Atrium iCAST covered stents. Magnet catheters were used to perforate the left pulmonary artery from the DAo, thereby establishing a transcatheter central shunt. Given the orientation of the vasculature, magnetic catheters could not be used for SVC-to-PA connections; however, perforation from the SVC to the right pulmonary artery was accomplished with a trans-septal needle and balloon target. Transcatheter Glenn or central shunts were successfully created in four swine.

Automated, compliant, high-flow common carotid to middle cerebral artery bypass

The authors describe the use of the Cardica C-Port xA Distal Anastomosis System to perform an automated, high-flow extracranial–intracranial bypass. The C-Port system has been developed and tested in coronary artery bypass surgery for rapid distal coronary artery anastomoses. Air-powered, it performs an automated end-to-side anastomosis within seconds by nearly simultaneously making an arteriotomy and inserting 13 microclips into the graft and recipient vessel. Intracranial use of the device was first simulated in a cadaver prepared for microsurgical anatomical dissection.

The authors used this system in a 43-year-old man who sustained a subarachnoid hemorrhage after being assaulted and was found to have a traumatic pseudoaneurysm of the proximal intracranial internal carotid artery. The aneurysm appeared to be enlarging on serial imaging studies and it was anticipated that a bypass would probably be needed to treat the lesion. An end-to-side bypass was performed with the C-Port system using a saphenous vein conduit extending from the common carotid artery to the middle cerebral artery. The bypass was demonstrated to be patent on intraoperative and postoperative arteriography. The patient had a temporary hyperperfusion syndrome and subsequently made a good neurological recovery.

The C-Port system facilitates the performance of a high-flow extracranial–intracranial bypass with short periods of temporary arterial occlusion. Because of the size and configuration of the device, its use is not feasible in all anatomical situations that require a high-flow bypass; however it is a useful addition to the armamentarium of the neurovascular surgeon.