Magnetic Anastomosis for Biliojejunostomy: First Prospective Clinical Trial

An experimental study of magnetic compression technique for ureterovesical anastomosis in rabbits

This study aimed to explore the feasibility of the magnetic compression technique (MCT) for ureterovesical anastomosis in a rabbit model with ureteral obstruction. The distal ureteral obstruction model using female New Zealand rabbits was induced by ligating the distal end of the right ureter with silk thread for four weeks. A pair of cylindrical NdFeB magnets (daughter magnet and parent magnet) with a hole in the center was used for the ureterovesical anastomosis. The daughter magnet and the parent magnet were respectively placed close to the obstruction site through the dilated proximal ureter and urethra, and then the daughter-parent magnets pair was attracted together automatically. Postoperative X-rays were taken to confirm the position of the magnets. The anastomotic stoma specimens were obtained two weeks postoperatively, and the anastomotic stoma formation was observed by the naked eye and histological staining. The operation time and the anastomotic burst pressure were measured. The ureter was significantly dilated in the fourth week after ligation, which satisfied the placement of the daughter magnet. The ureterovesical magnet placements were successfully performed in ten experimental rabbits, with an operation time of 36.5 ± 6.09 min. The parent and daughter magnets attracted each other well and were subsequently removed through the urethra two weeks postoperatively, resulting in the establishment of ureterovesical anastomosis. The anastomotic burst pressure was 147.5 ± 14.59 mmHg. Gross specimens and histological examination of the anastomotic stoma showed that the anastomotic stoma healed well. MCT is feasible and simple for ureterovesical anastomosis.

A novel micromagnetic ring used for biliary-enteric anastomosis in rats

BACKGROUND

To explore the feasibility of micromagnetic ring in establishing biliary-enteric anastomosis in a rat model.

METHODS

A new micromagnetic ring suitable for rat biliary-enteric anastomosis model was designed and fabricated. The common bile ducts of 20 Sprague-Dawley albino rats were ligated and dilated after 2 weeks. Surgery for biliary-enteric anastomosis was completed by using micromagnetic ring. The anastomosis time, postoperative survival rate, liver function, liver histopathology, and complications were recorded. After 28 days, anastomotic specimens were obtained to observe healing with the naked eye and light microscopy.

RESULTS

Among the 20 Sprague-Dawley albino rats, one rat showed bile leakage and died one week after ligation of the common bile duct and another rat was removed from the experiment because there was no obvious dilatation of the common bile duct. The remaining 18 rats successfully underwent surgery for biliary-enteric anastomosis using micromagnetic ring, with an average anastomosis time of 7.10 ± 1.15 min (range, 5.17-9.50 min). The expulsion time of micromagnetic anastomosis rings was 11.94 ± 2.48 days (range, 8-17 days). The bilirubin level dropped to normal 1 week after surgery. Biliary-enteric anastomotic specimens were obtained 28 days after surgery, and microscopic observation showed that the mucosal layer of the anastomosis had good continuity and the anastomosis was smooth.

CONCLUSION

A micromagnetic ring can be used to construct a rat biliary-enteric anastomosis model, and it offers advantages, such as simple operation and reliable anastomosis effect.

Esophageal magnetic compression anastomosis in dogs

BACKGROUND

Magnetic compression anastomosis (MCA) is a novel suture-free reconstruction of the digestive tract. It has been used in gastrointestinal anastomosis, jejunal anastomosis, cholangioenteric anastomosis and so on. The traditional operative outcomes of congenital esophageal atresia and benign esophageal stricture are poor, and there are too many complications postoperatively.

AIM

To test MCA technology to reconstruct the esophagus in dogs, prior to studying the feasibility and safety of MCA in humans.

METHODS

Thirty-six dogs were randomized into either the study or control group (n = 18 per group). The dogs in the study group were subjected to end-to-end esophageal anastomosis with the magnetic compression device, while those in the control group underwent hand-sewn anastomosis with 4-0 absorbable multifilament Vicryl. We used interrupted single-layer inverting sutures. The anastomosis time, gross appearance, weight and pathology of the anastomosis were evaluated at one month, three months and six months postoperatively.

RESULTS

The anastomosis time of the MCA group was shorter than that of the hand-sewn group (7.5 ± 1.0 min vs 12.5 ± 1.8 min, P < 0.01). In the MCA group, X-ray examination was performed every day to locate the magnetic device in the esophagus before the magnetic device fell off from the esophagus. In the hand-sewn group, dogs did not undergo X-ray examination. One month after the surgeries, the mean weight of the dogs in the hand-sewn group had decreased more than that of the dogs in the MCA group (11.63 ± 0.71 kg vs 12.73 ± 0.80 kg, P < 0.05). At 3 mo and 6 mo after the operation, the dogs' weights were similar between the two groups (13.75 ± 0.84 kg vs 14.03 ± 0.82 kg, 14.93 ± 0.80 kg vs 15.44 ± 0.47 kg). The number of inflammatory cells in MCA group was lower than that in hand-sewn group on 1 mo after operation.

CONCLUSION

MCA is an effective and safe method for esophageal reconstruction. The anastomosis time of the MCA group was less than that of the hand-sewn group. This study shows that MCA technology may be applied to human esophageal reconstruction, provided these favorable results are confirmed by more publications.

Establishment of Yan-Zhang's staging of digestive tract magnetic compression anastomosis in a rat model

Magnetic compression anastomosis, also known as magnamosis, is a safe and feasible method for digestive tract anastomosis. However, the pathological process involved in magnamosis of the digestive tract has not been investigated. This study aimed to establish the stages of digestive tract magnamosis in a rat model. Eighty-four Sprague–Dawley albino rats (200–250 g) were randomly divided into 14 groups (n = 6 per group). All rats underwent colonic magnamosis. Starting from postoperative day (POD) 1, one group of rats was sacrificed every other day to obtain the specimens. Burst pressure at the anastomotic site of each specimen was examined. Gross and histological examination of the anastomotic site was performed to establish the stages of the digestive tract magnamosis. Colonic magnamosis was successfully performed in all rats and the mean anastomosis time was 5.62 ± 0.91 min. The postoperative survival rate was 100%. The lowest anastomotic burst pressure was 78.33 ± 3.44 mmHg on POD3. The anastomotic burst pressure gradually increased and stabilized on POD21. Macroscopic and histological examination showed that the anastomotic mucosal and serosal layer did not heal on POD1. The serosal layer of the anastomosis healed by adhesion on POD3, and the mucosal layer began to heal on POD3-11 and was established by POD21. According to the anastomotic bursting pressure, digestive tract magnamosis can be staged into the magnetic maintenance, fragile, strengthening, and stable phases, which on histology correspond to the serosal adhesion formation, serosal healing, mucosal healing, and stereotyping, respectively.

A novel magnetic compression technique for cystostomy in rabbits

Magnetic compression technique (MCT) is a popular new anastomosis method. In this paper, we aimed to explore the feasibility of use of MCT for performing cystotomy in rabbits. The parent magnets and daughter magnets for rabbit cystostomy were designed and manufactured according to the anatomical characteristics of rabbit lower urinary tract. Twelve female New Zealand rabbits were used as animal models. After anesthesia, a daughter magnet was inserted into the bladder through the urethra, and the parent magnet was placed on the body surface projection of the bladder over the abdominal wall. The two magnets automatically attract each other. Postoperatively, the state of magnets was monitored daily, and the time when the magnets fell off was recorded. Cystostomy with MCT was successfully performed in all twelve rabbits. The mean operation time was 4.46 ± 0.75 min. The magnets fell off from the abdominal wall after a mean duration of 10.08 ± 1.62 days, resulting in the formation of bladder fistula. Macroscopic and microscopic examination showed that the fistula was well formed and unobstructed. The junction between bladder and abdominal wall was tight and smooth. We provide preliminary experimental evidence of the safety and feasibility of cystostomy based on MCT.

Regional anticoagulation magnetic artificial blood vessels constructed by heparin-PLCL core-shell nanofibers for rapid deployment of veno-venous bypass

Veno-venous bypass (VVB) is necessary for maintaining hemodynamic and internal environment stabilities in complex liver surgeries. However, the current VVB strategies require systematic anticoagulation and are time-consuming, leading to unexpected complications. This study aims to overcome these limitations by using a novel magnetic artificial blood vessel constructed with heparin-PLCL core-shell nanofibers. Coaxial electrospinning was used to fabricate core-shell nanofibers with heparin encapsulated into the core layer. The microstructure, physical and chemical properties, hemocompatibility, and heparin release behavior were characterized. The regional anticoagulation magnetic artificial vessel was constructed with these nanofibers and used to perform VVB in a rat liver transplantation model for in vivo evaluation. The core-shell nanofibers appeared smooth and uniform without apparent defects. Fluorescence and TEM images indicated that heparin was successfully encapsulated into the core layer. In addition, the in vitro heparin release test presented a two-phase release profile, burst release at day 1 and sustained release from days 2 to 14, which resulted in better hemocompatibility. The VVB could be rapidly deployed in 3.65 ± 0.83 min by the magnetic artificial vessel without systemic anticoagulation. Moreover, the novel device could reduce portal pressure and abdominal organ congestion, protect intestinal function, and increase the survival rate of liver transplantation with a long anhepatic phase from 0 to 65%. In summary, VVB can be rapidly deployed using regional anticoagulation magnetic artificial blood vessels without systemic anticoagulation, which is promising for improving patient outcomes after complex liver surgery.

Construction of Esophagogastric Anastomosis in Rabbits with Magnetic Compression Technique

PURPOSE

The magnetic compression technique (MCT) is a new surgical method that has been used for gastrointestinal anastomosis, choledochojejunostomy, and intestinal anastomosis, but there are no reports on its use for esophagogastric anastomosis. This study aimed to investigate the feasibility of using MCT to fashion esophagogastric anastomoses in rabbits.

METHODS

Twenty rabbits were randomized into an MCT group (study group, n = 10) and a hand-sewn group (control group, n = 10). The magnetic compression anastomosis device used in this study was made of neodymium iron boron (NdFeB) and possessed parent (PMR) and daughter (DMR) magnetic rings. To fashion the anastomosis, the PMR and DMR were inserted into the lower esophagus and gastric fundus, respectively. The coupled magnets automatically compressed the sandwiched tissues and were expelled once the anastomosis was installed. The two groups were further compared in terms of the anastomosis construction time, survival rate, and postoperative complications. One month after the anastomosis was installed, the burst pressure and gross appearance of the anastomoses were evaluated.

RESULTS

The anastomosis construction time in the study group was significantly shorter than that in the control group (10.50 ± 1.58 min vs. 18.60 ± 2.22 min; P < 0.05), and the magnetic rings were defecated out in 10.70 ± 3.49 days. The incidence of anastomotic blockage in both the study and control groups did not differ significantly (0%, 0/10 vs. 20%, 2/10; P > 0.05). Anastomotic leakage was not found in either of the groups, and the anastomoses burst pressures were similar in the two groups. However, the magnetically compressed anastomoses in the study group had a relatively smoother gross appearance than the hand-sewn anastomoses.

CONCLUSION

The magnetic compression anastomosis device is a safe and feasible tool for fashioning esophagogastric anastomoses in this animal model.

Physical Bases, Indications, and Results of the Use of Magnets in Digestive Surgery: A Narrative Review

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.

Cholangiojejunostomy Using a Novel Magnamosis Device: Initial Clinical Results

BACKGROUND

Cholangiojejunostomy (CJ) is a popular operation; however, no specific anastomotic device is available. A novel magnamosis device for CJ was developed in 2017; here, we evaluated the feasibility and safety of the device.

METHODS

Between January 2017 and December 2019, 23 patients who underwent CJ using a novel magnamosis device were enrolled. For the CJ: the parent magnet was placed in the proximal duct, and the purse-string suture was tightened over the rod of the parent magnet. The magnamosis device was introduced into the jejunum, and the mandrel penetrated the jejunum at the anastomotic site, before insertion into the rod of the parent magnet. After rotating the knob, the distance between two magnets was shortened enough to achieve coupling.

RESULTS

Sixteen patients (69.6%) underwent open CJ, while 7 (30.4%) underwent laparoscopic CJ; 21 patients (91.3%) underwent choledochojejunostomy, and 2 (8.7%) underwent right or left hepatic duct jejunostomy. The mean time for completion of CJ was 9.2±2.5 min; it was significantly shorter for open CJ than for the laparoscopic way (8±1.2 min vs. 11.8±2.5 min, P<0.05). Only one patient (4.3%) suffered bile leakage after operation and was cured by conservative treatment. The magnets were discharged with a postoperative duration of 66.7±47.2 days, with a 100% expulsion rate. After a median follow-up of 15 months, only one patient (4.3%) developed inflammatory anastomotic stricture.

CONCLUSION

The novel magnamosis device is a simple, safe, and effective modality for CJ.

Innate Immune Regulation Under Magnetic Fields With Possible Mechanisms and Therapeutic Applications

With the wide applications of magnetic fields (MFs) in medicine, researchers from different disciplines have gained interest in understanding the effect of various types of MFs on living cells and organisms. In this paper, we mainly focus on the immunological and physical aspects of the immune responses and their mechanisms under different types of MFs. Immune cells were slightly affected by low-frequency alternating MFs but were strongly influenced by moderate-intensity MFs and high-gradient MFs (HGMFs). Larger immune cells, such as macrophages, were more sensitive to HGMFs, which biased the cell polarization into the anti-inflammatory M2 phenotype. Subject to the gradient forces of varying directions and strength, the elongated M2 macrophage also remodeled the cytoskeleton with actin polymerization and changed the membrane receptors and ion channel gating. These alterations were very similar to changes caused by the small GTPase RhoA interference in macrophage. Regulation of iron metabolism may also contribute to the MF effects in macrophages. High MFs were found to regulate the iron content in monocyte-/macrophage-derived osteoclasts by affecting the expression of iron-regulation genes. On the other hand, paramagnetic nanoparticles (NPs) combined with external MFs play an important role in T-cell immunity. Paramagnetic NP-coated T-cells can cluster their T-cell receptors (TCRs) by using an external MF, thus increasing the cell–cell contact and communication followed by enhanced tumor killing capacity. The external MF can also guide the adoptively transferred magnetic NP-coated T-cells to their target sites in vivo, thus dramatically increasing the efficiency of cell therapy. Additionally, iron oxide NPs for ferroptosis-based cancer therapy and other MF-related therapeutic applications with obstacles were also addressed. Furthermore, for a profound understanding of the effect of MFs on immune cells, multidisciplinary research involving both experimental research and theoretical modeling is essential.

Fedora-type magnetic compression anastomosis device for intestinal anastomosis

BACKGROUND

Although previous studies have confirmed the feasibility of magnetic compression anastomosis (MCA), there is still a risk of long-term anastomotic stenosis. For traditional MCA devices, a large device is associated with great pressure, and eventually increased leakage.

AIM

To develop a novel MCA device to simultaneously meet the requirements of pressure and size.

METHODS

Traditional nummular MCA devices of all possible sizes were used to conduct ileac anastomosis in rats. The mean (± SD) circumference of the ileum was 13.34 ± 0.12 mm. Based on short- and long-term follow-up results, we determined the appropriate pressure range and minimum size. Thereafter, we introduced a novel “fedora-type” MCA device, which entailed the use of a nummular magnet with a larger sheet metal.

RESULTS

With traditional MCA devices, the anastomoses experienced stenosis and even closure during the long-term follow-up when the anastomat was smaller than Φ5 mm. However, the risk of leakage increased when it was larger than Φ4 mm. On comparison of the different designs, it was found that the “fedora-type” MCA device should be composed of a Φ4-mm nummular magnet with a Φ6-mm sheet metal.

CONCLUSION

The diameter of the MCA device should be greater than 120% of the enteric diameter. The novel “fedora-type” MCA device controls the pressure and optimizes the size.

Magnetic Compression Anastomosis in Laparoscopic Pancreatoduodenectomy: A Preliminary Study

BACKGROUND

Laparoscopic pancreatoduodenectomy (LPD) is a minimally invasive technique widely developed in the last few decades. Although magnetic compression anastomosis (magnamosis) is used during cholangiojejunostomy, its applicability in LPD has not yet been reported. Herein, we evaluated the feasibility and effectiveness of magnamosis in LPD.

METHODS

Between January 2018 and December 2019, seven patients who underwent laparoscopic magnetic compression choledochojejunostomy (LMC-CJ) or laparoscopic magnetic compression pancreatojejunostomy (LMC-PJ) in LPD were enrolled. After LPD, a parent magnet with or without a drainage tube was placed in the proximal bile duct and pancreatic duct of each patient. Daughter magnets were introduced to couple with the parent magnets at the desired sites. A close postoperative surveillance of magnet movements was performed. Various relevant data were collected, and all patients were followed up until February 2020.

RESULTS

LPD was successfully completed in all seven patients, of which seven underwent LMC-CJ and two received LMC-PJ. The median time needed for completion of LMC-CJ was 11 min (range, 8-16). The cost time for the two cases of LMC-PJ was 12 and 15 min, respectively. After a median time of 50 d (range, 40-170) postoperation, all magnets were expelled. No leakages of LMC-CJ or LMC-PJ were observed after operation. After a median follow-up period of 11 mo (range, 4-18), there was no incidence of anastomotic stricture.

Magnetic compression anastomosis for biliojejunostomy and pancreaticojejunostomy in Whipple's procedure: An initial clinical study

BACKGROUND AND AIM

Magnetic anastomosis has been attempted in biliary and intestinal reconstruction. The objective of the current study was to introduce an initial clinical use of magnetic compression anastomosis for pancreaticojejunostomy and biliojejunostomy in Whipple's procedure.

METHODS

Patients with peri-ampullary carcinoma and dilated bile and pancreatic ducts were prospectively enrolled from 2016 to 2017. After pancreaticoduodenectomy, an appropriate mother magnet and drainage tube was placed in the proximal bile duct and pancreatic duct. The daughter magnets were introduced to mate with the mother magnets at the anastomotic sites. A close postoperative surveillance and routine cholangiopancreaticography via the drainage tube were performed.

RESULTS

One female and three male patients with a median age of 69 years (range, 57-77) were included. The diameter of the common bile ducts and pancreatic ducts ranged from 8 to 15 mm, and 7 to 10 mm, respectively. The median time duration for biliojejunostomy and pancreaticojejunostomy was 7 (range, 5-8 min) min and 9 (range, 8-10 min) min, respectively. The median time of biliojejunostomy and pancreaticojejunostomy formation was 17 (range, 15-21 days) days and 11 (range, 10-18 days), respectively. With a median follow up of 313 days, one patient developed biliary anastomotic stricture at 11 months after surgery, and underwent stent placement via percutaneous transhepatic drainage sinus, and recovered well.

CONCLUSIONS

Magnetic anastomosis is safe, effective, and simple for both biliojejunostomy and pancreaticojejunostomy in Whipple's procedure.

Use of magnets in gastrointestinal surgery

BACKGROUND

Laparoscopic and endoscopic surgery has undergone vast progress during the last 2 decades, translating into improved patient outcomes. A prime example of this development is the use of magnetic devices in gastrointestinal surgery. Magnetic devices have been developed and implemented for both laparoscopic and endoscopic surgery, providing alternatives for retraction, anchoring, and compression among other critical surgical steps. The purpose of this review is to explore the use of magnetic devices in gastrointestinal surgery, and describe different magnetic technologies, current applications, and future directions.

METHODS

IRB approval and written consent were not required. In this review of the existing literature, we offer a critical examination at the use of magnets for gastrointestinal surgery currently described. We show the experiences done to date, the benefits in laparoscopic and endoscopic surgery, and additional future implications.

RESULTS

Magnetic devices have been tested in the field of gastrointestinal surgery, both in the contexts of animal and human experimentation. Magnets have been mainly used for retraction, anchoring, mobilization, and anastomosis.

CONCLUSION

Research into the use of magnets in gastrointestinal surgery offers promising results. The integration of these technologies in minimally invasive surgery provides benefits in various procedures. However, more research is needed to continually evaluate their impact and implementation into surgical practice.

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.