INTRODUCTION
Minimally invasive surgery (MIS) is a continuously evolving field with multiple developments happening since the adoption of laparoscopic cholecystectomy in the late 1980s.1 MIS has become the standard of care for a wide variety of procedures as it has been proven to be safe and effective.2 The advantages of this type of approach are related to better organ exposure and smaller incisions, which leads to decreased pain, improved surgical results, and decreased hospital length of stay.2,3 In an effort to minimize further the invasiveness of laparoscopic procedures, the field of magnetic laparoscopic surgery (MLS) was established.4,5
The concept of MLS is based on the use of magnetic fields to manipulate surgical instruments without making an incision. This technology was first employed in animal models, which were then followed by human cases of laparoscopic cholecystectomy.4–8 In 2016, the first prospective single-arm study utilizing MLS was published.9 In this prospective multicenter clinical trial, 50 patients underwent a 3-port laparoscopic cholecystectomy with the assistance of MLS showing it was safe and feasible. Following this original study and its approval by the Food and Drug Administration multiple authors started reporting their positive results.10–15
The principles of MLS were then coupled to those of robotic surgery when Guerron et al11, in conjunction with the da Vinci Single Port platform (Intuitive Surgical, Sunnyvale, CA), performed a laparoscopic cholecystectomy. This combination of MLS and robotic surgery was further explored by other authors as well, demonstrating its safety and feasibility.15–20 This coupling of technologies led to the first in human experience of the Levita Robotic Platform (Levita Magnetics Corp., Menlo Park, CA), which was done in a series of patients undergoing laparoscopic cholecystectomy using a laparoscopic magnetic grasper with a detachable tip and an external robotically controlled manipulator.21
Nevertheless, until now, this novel Magnetic Robotic Platform had not been prospectively evaluated. The purpose of the present study was to evaluate the safety and feasibility of this novel Magnetic Robotic Platform within a prospective clinical trial using reduced-port laparoscopic cholecystectomy and laparoscopic bariatric surgery.
MATERIALS AND METHODS
From May 2021 to December 2021, a prospective, multicenter, single-arm, open-label study was conducted to assess the safety and feasibility of the Levita Robotic Platform (LRP) during reduced-port laparoscopic cholecystectomy and laparoscopic bariatric surgery. The LRP at this time is authorized for clinical evaluation only and not yet cleared for commercial use.
The LRP includes 2 robotic arms each with 7 degrees of freedom that provides control to an external magnetic controller and a laparoscopic camera (Fig. 1). The detachable grasper and delivery/retrieval shaft make up the magnetic surgical system (MSS) (Fig. 2). Once the MSS is inserted through a ≥10 mm laparoscopic trocar port and attached to the desired tissue, it is detached from the delivery/retrieval shaft and controlled externally using the Magnetic Controller attached to the robotic arm (Fig. 3). Manipulation of the tissue is maintained through the magnetic field attraction between the detachable grasper and the Magnetic Controller. The MSS is single-use, disposable, and provided sterile to the user. The system is console-free, keeping the surgeon next to the patient in the sterile field at all times. The system is commanded at the bedside with a foot controller that manipulates both robotic arms. This enables the operative surgeon to use both arms with full control of the laparoscopic instruments.
;)
FIGURE 1.: Levita Robotic Platform.
FIGURE 2.: Magnetic grasper device.
FIGURE 3.: Magnetic controller.
Patients 18 years and older scheduled for elective laparoscopic cholecystectomy and laparoscopic bariatric surgery were recruited. These procedures were chosen as there are prior studies demonstrating the safety of MSS in addition to Food and Drug Administration clearance for these indications.9,14 Patients with severe comorbid conditions, pregnancy or with electrometrical/ferromagnetic implants were excluded. The study was conducted in 3 clinical sites in Chile receiving prior Institutional Review Board approval by each institution and following the Principles of Good Clinical Practice and the International Ethical Guidelines for Biomedical Research Involving Human Subjects. Written informed consent was obtained from all participants before enrollment. The present study was registered on ClinicalTrials.gov (NCT05353777). All of the surgeons were trained to use the robotic platform with a laparoscopic trainer model for approximately 2 hours before in human experience and also had experience with the non-robotic magnetic surgery platform. No other cases were done outside of the clinical trial. The primary endpoints evaluated were safety and feasibility outcomes.
Safety was defined as (1) there is no evidence of a device failure defined as a device breakage or other malfunction requiring additional surgical intervention, including reoperation and/or device removal and (2) there is no serious adverse event probably or definitely related to the device resulting in: (A) revision/removal of the device, (B) permanent damage to the organ, and/or C) death of the study subject. Patients were followed at 7 and 30 days post-procedure. All adverse events were reported, and the principal investigator determined the adverse event severity and the relation of each adverse event to the device. An independent and external medical monitor reviewed all adverse events. All surgeries were digitally recorded for post-procedure analysis if needed.
Feasibility was defined as the ability to utilize MSS and LRP as intended during the laparoscopic procedures while monitoring (1) the ability of the LRP to engage, move, and decouple with the MSS as intended/controlled by the surgeon, (2) the ability of the LRP to provide adequate laparoscopic visualization via a conventional laparoscopic system as intended/controlled by the surgeon, (3) successful completion of the procedure with the MSS and LRP, and (4) whether the MSS or the LRP cannot be successfully used due to a MSS or LRP performance issue resulting in conversion to an open procedure.
The procedures were planned to be conducted with a reduced-port technique, utilizing 3 ports instead of 4 for cholecystectomy and 4 instead of 5 for bariatric surgery. In all cases, the epigastric port was spared. During cholecystectomy, the MSS was used to retract the gallbladder fundus to provide adequate retraction to expose Calot’s triangle. In the case of bariatric surgery, it was used to retract the liver and expose the stomach. Adequate visualization was considered when the case was completed without the need for an extra instrument to provide retraction.
Other measured variables were age, preoperative body mass index (BMI), operative time (time from the first incision to the last suture’s placement), device use time (time between grasper introduction and correct position and release, time between correct position and coupling with the external magnet, and total time of coupling between the internal grasper and the external magnet), laparoscope coupling with the robotic arm, unintentional decoupling, damage or breakage of the detachable grasper, conversion, number of 5 mm incisions, number of 10 mm incisions, number of 12 mm incisions, blood loss, time spent in the post-anesthesia care unit, and length of stay (time from post-anesthesia care unit admission until discharge).
RESULTS
All patients were invited to participate accepted to be enrolled and were included in the study. Thirty patients undergoing laparoscopic surgery were recruited, including 15 sleeve gastrectomies, 14 cholecystectomies, and 1 Roux-en-Y gastric bypass. The procedures were done by 3 different surgeons. All subjects provided written informed consent before their study enrollment. The entire cohort consisted of 22 females and 8 males with a mean age of 39 years (22–69 years) and mean BMI of 33 kg/m2 (21.6–50.4 kg/m2).
The indication for laparoscopic cholecystectomy was symptomatic cholelithiasis in all 14 patients. This group consisted of 11 females (79%) and 3 males (21%), median age of 38.5 years, and median BMI of 26.9 kg/m2. Patients undergoing laparoscopic bariatric surgery had morbid obesity with a median BMI of 35.9 kg/m2. The group consisted of 11 females (68.8%) and 5 males (31.2%) with median age of 38.5 years. Baseline patient demographics are summarized in Table 1.
TABLE 1. -
Baseline Patient Characteristics
| Attribute |
Result |
| Cohort |
Cholecystectomy |
Bariatric |
| Sex |
| Female |
22 (73%) |
11 (79%) |
11 (69%) |
| Male |
8 (27%) |
3 (21%) |
5 (31%) |
| Age |
| Mean |
39.1 |
41.1 |
37.4 |
| Minimum |
22 |
28 |
22 |
| Maximum |
69 |
69 |
60 |
| BMI (kg/m2) |
| Median |
33.1 |
26.9 |
35.9 |
| Minimum |
21.6 |
21.6 |
30.8 |
| Maximum |
50.5 |
35.0 |
50.5 |
BMI indicates body mass index.
There was no need for additional tools or conversion to an open procedure in any of the cases. All laparoscopic cholecystectomies and laparoscopic bariatric surgeries were done using a reduced-port technique employing 3 and 4 ports, respectively. Operative times and utilization of LRP are shown in Tables 2 and 3. Mean number of 5 mm ports was 1 and the mean number of 10–12 mm ports was 2 for laparoscopic cholecystectomies and 3 for laparoscopic bariatric surgeries. On average, the magnet was moved 2.3 times per case with a range from 1 to 9 times. All cholecystectomies were performed without a surgical assistant, so the surgeons were able to complete the procedures independently.
TABLE 2. -
Intraoperative and Postoperative Characteristics
| Operative characteristic |
Laparoscopic Cholecystectomy |
Laparoscopic Sleeve |
Laparoscopic Bypass* |
| Successful laparoscopic approach (n) |
14 |
100% |
15 |
100% |
1 |
100% |
| Operative time, min (median, IQR) |
62 |
53–71 |
64 |
59–76 |
173 |
NA |
| Mean number of incisions (n, size) |
3 |
10–12 mm × 2 |
4 |
12 mm × 3 |
4 |
12 mm × 3 |
| 5 mm × 1 |
|
5 mm × 1 |
5 mm × 1 |
| Conversion (n, %) |
0 |
0% |
0 |
0% |
0 |
0% |
| Length of stay (≤1 d) (n, %) |
13 |
93% |
15 |
100% |
1 |
100% |
| Adverse events related to the device (n, %) |
1† |
7% |
1‡ |
6.7% |
0 |
0% |
| Estimated blood loss (≤50 mL) (n, %) |
14 |
100% |
15 |
100% |
1 |
100% |
*Individually reported without median or IQR.
†Intra-peritoneal abdominal wall petechiae resolved without sequela.
‡Minor liver capsule abrasion resolved without sequela.
IQR indicates interquartile range; NA, not applicable.
TABLE 3. -
Device Utilization
| Device characteristic |
Laparoscopic Cholecystectomy |
Laparoscopic Sleeve |
Laparoscopic Bypass* |
| Magnetic grasper introduced time, min, median (IQR) |
11.5 (10–13) |
8 (7.5–9) |
9 (NA) |
| Magnetic grasper position and release time, min, median (IQR) |
12 (10.25–14) |
9 (8–11) |
11 (NA) |
| Magnetic grasper first coupled time, min, median (IQR) |
13.5 (11–14.75) |
9 (9–12.5) |
12 (NA) |
| Magnetic grasper removed time, min, median (IQR) |
40 (34.75–47.5) |
53 (48–62.5) |
166 (NA) |
| Laparoscope attached time, min, median (IQR) |
8.5 (8–10) |
7 (6–8.5) |
8 (NA) |
| Laparoscope inserted time, min, median (IQR) |
10 (9–11.75) |
8 (6.5–10) |
8 (NA) |
| Times laparoscope was removed, median (IQR) |
1 (1–2) |
1 (0–2) |
4 (NA) |
| Adequate visualization and retraction, n (%) |
14 (100) |
15 (100) |
1 (100) |
| No additional tools, n (%) |
14 (100) |
15 (100) |
1 (100) |
Times are reported from the start time of the procedure.
*Individually reported without median or IQR.
IQR indicates interquartile range; NA, not applicable.
No major adverse events related to the device were reported. Two minor adverse events related to the device were described. In one of the laparoscopic cholecystectomy cases, there were abdominal wall petechiae that resolved without sequela. Furthermore, in one of the sleeve gastrectomy cases, there was a minor liver capsule abrasion that resolved without sequela. No serious adverse events occurred during the study. There were, in addition, 9 other mild adverse events during the trial not related to the study device, all of which resolved without sequela. All patients completed their scheduled follow-ups at 7 and 30 days postoperative. The estimated blood loss during the procedure was less than 50 mL for all procedures. The majority of the patients (97%) were discharged during the immediate 24 hours after the procedure.
In 5 cases, system issues were noted but none of these had significant impact on the procedures or patient outcomes. In 1 case, a malfunction of the internal grasper was noted before its introduction to the patient and the grasper was replaced. In 1 case, there was a slight misalignment of the camera holder. In 3 other cases, recoverable errors were noticed; these were related to the connector of the foot controller.
DISCUSSION
The use of magnetism in laparoscopic surgery has evolved since it was first described in 2007.4 The increased use of MLS during the past decade has shown this technology to be both safe and feasible.9–20 Incorporation of the principles of MLS to robotic surgery may create a synergism of both techniques and escalate its individual benefits. In this prospective clinical trial, the safety and feasibility of a novel Magnetic Robotic Platform was demonstrated. This new system can be used in reduced-port laparoscopic cholecystectomies and bariatric procedures.
The combination of MLS and robotic surgery was proven to be safe and feasible in prior studies while combining different platforms.15–20 In 2021, Barajas-Gamboa et al21 reported the first in human experience of a single robotic arm attached to an external magnet, which accurately manipulated an internal grasper to achieve adequate exposure during laparoscopic cholecystectomy. Different to that first study, the present study utilized a platform containing 2 robotic arms with 7 degrees of freedom that provided control to an internal magnetic retractor and a laparoscopic camera. The system is console-free, keeping the surgeon next to the patient in the sterile field at all times while providing stable view of the surgery.
Adequate retraction to provide appropriate visualization of the surgical field is fundamental for any type of surgery. This principle remains valid for laparoscopic surgery. The Magnetic Robotic Platform provided adequate visualization and retraction in all of the cases. In addition, no need for conversion or additional instruments were required to complete the procedures.
Although adequate exposure is fundamental, the benefits of adding another instrument needs to be balanced against the risk of inflicting injury.22 The use of additional trocars for a determined procedure is sometimes taken for granted. Surgeons should consider that each trocar placed is an increased risk of causing an injury to the soft tissues, hollow viscus, solid viscus, and vascular structures.23 Also, this risk is carried into the postoperative period, as the incisions are still prone to the development of trocar site hernias.24 One of the advantages of MLS is the feasibility of performing reduced-port surgery while still providing adequate visualization of the surgical field.
As mentioned before, some of the main advantages of MIS are related to smaller incisions leading to decreased pain.2 Following this logic, decreasing number of incisions will likely decrease postoperative pain. Although pain was not evaluated as a primary outcome in the present study, previous reports of MLS have acknowledged less postoperative pain when employing this technology.9,25 A retrospective case-matched comparison between MSS and external retractor including 296 patients demonstrated that patients operated on using the magnetic retraction had lower pain scores at 12 hours (2.9 vs 3.8; P = 0.004) and shorter length of stay (1.5 vs 1.8; P = 0.0051).25
Patient safety is imperative in the operating room and surgeons need to remember the dictum primum non nocere.26,27 Having this in mind, the primacy when assessing new technologies must be its safety. MLS has been present in surgery for more than a decade with multiple studies demonstrating how it is safe to employ this technology in the operating room.9–20 In this first prospective clinical trial, the safety was closely monitored. No serious adverse events occurred related to the device or throughout the study protocol. However, continuous monitoring of all new technologies is warranted to assure patients’ safety.
As previously described, there were 2 minor adverse events related to the device, both of which resolved without any clinical symptoms or sequela. These adverse events consisted of a minor liver abrasion and abdominal wall petechiae, which had been previously describe with the use of MSS.9,14 Patients with severe obesity are at increased risk of iatrogenic liver injury during laparoscopic procedures requiring retraction of this organ as a consequence of a greater prevalence of fatty liver disease. In those procedures requiring liver retraction, the surgeons need to assess the risk and benefit of each one of the different instruments available given that complications such as capsular tear, parenchymal fracture, parenchymal congestion and even parenchymal necrosis can occur with different types of retractors.28
Our study has some limitations worth noting. First, the study was done in a relatively small group of patients and by experienced minimally invasive surgeons familiar with magnetic surgery. This may limit the generalizability of our results. Second, this novel Magnetic Robotic Platform was not compared with other technologies and based on the present study, we cannot assume this new technology is superior to current standard treatments. Third, the study did not evaluate pain as a primary outcome, and no conclusions can be drawn in such aspect as mentioned before. Finally, the cost of the platform was not evaluated, which limits any comments of such regard.
This is the first prospective, multicenter, single-arm study demonstrating the safety and feasibility of a novel Magnetic Robotic Platform. The combination of magnetic surgery plus robotics may provide benefit to both patients and surgeons. This novel emerging technology should undergo additional evaluation in a more generalized setting for further analysis and broader applications.
ACKNOWLEDGMENTS
The authors thank all those who contributed to this clinical trial, without their help and commitment, it could not have been completed. Special thanks to Dr Francisco Riquelme for his help in the study, Javiera Obreque for monitoring the data, and Vivian Soto as the main research coordinator.
I.R., D.P., and M.K. involved in background theory. I.R., J.J., C.C., and R.L. involved in design of experiment. G.R.-V., I.R., J.J., C.C., and R.L. involved in data analysis and interpretation. G.R.-V. and M.K. involved in writing of the article. All authors involved in reviewing and/or revising the text.
REFERENCES
1. Vecchio R, MacFayden BV, Palazzo F. History of laparoscopic surgery. Panminerva Med. 2000;42:87–90.
2. Epstein AJ, Groeneveld PW, Harhay MO, et al. Impact of minimally invasive surgery on medical spending and employee absenteeism. JAMA Surg. 2013;148:641–647.
3. Narvaez CA, Ortega C, Davalos G, et al. Scars matter: the importance of incision decisions in bariatric patients. Obes Surg. 2020;30:1611–1615.
4. Park S, Bergs RA, Eberhart R, et al. Trocar-less instrumentation for laparoscopy: magnetic positioning of intra-abdominal camera and retractor. Ann Surg. 2007;245:379–384.
5. Domínguez GM. Colecistectomía con un trócar asistida por imanes de neodimio. Reporte de un caso. Rev Mex Cir Endoscop. 2007;8:172–176.
6. Kume M, Miyazawa H, Abe F, et al. A newly designed magnet-retracting forceps for laparoscopic cholecystectomy in a swine model. Minim Invasive Ther Allied Technol. 2008;17:251–254.
7. Kume M, Miyazawa H, Iwasaki W, et al. The use of magnetic anchors in the bowel lumen for laparoscopic anterior resection of rectosigmoid colon in pigs: with video. World J Surg. 2008;32:2425–2428.
8. Dominguez G, Durand L, De Rosa J, et al. Retraction and triangulation with neodymium magnetic forceps for single-port laparoscopic cholecystectomy. Surg Endosc. 2009;23:1660–1666.
9. Rivas H, Robles I, Riquelme F, et al. Magnetic surgery: results from first prospective clinical trial in 50 patients. Ann Surg. 2018;267:88–93.
10. Haskins IN, Strong AT, Allemang MT, et al. Magnetic surgery: first U.S. experience with a novel device. Surg Endosc. 2018;32:895–899.
11. Guerron AD, Ortega C, Park C, et al. Magnetic robot–assisted single-incision cholecystectomy. CRSLS. 2017;73:e2017.00073.
12. Davalos G, Lan BY, Diaz R, et al. Single-center experience with magnetic retraction in colorectal surgery. J Laparoendosc Adv Surg Tech. 2019;29:1033–1037.
13. Davis M, Davalos G, Ortega C, et al. Magnetic liver retraction: an incision-less approach for less invasive bariatric surgery. Obes Surg. 2019;29:1068–1073.
14. Luengas R, Galindo J, Castro M, et al. First prospective clinical trial of reduced incision bariatric procedures using magnetic liver retraction. Surg Obes Relat Dis. 2021;17:147–152.
15. Steinberg RL, Johnson BA, Cadeddu JA. Magnetic-assisted robotic surgery: initial case series of reduced-port robotic prostatectomy. J Robotic Surg. 2019;13:599–603.
16. Steinberg RL, Johnson BA, Meskawi M, et al. Magnet-assisted robotic prostatectomy using the da Vinci SP robot: an initial case series. J Endourol. 2019;33:829–834.
17. Steinberg RL, Johnson BA, Cadeddu JA. Magnetic-assisted robotic surgery to facilitate reduced-port radical prostatectomy. Urology. 2019;126:237.
18. Ganesan V, Goueli R, Rodriguez D, et al. Single-port robotic-assisted laparoscopic sacrocolpopexy with magnetic retraction: first experience using the SP da Vinci platform. J Robotic Surg. 2020;14:753–758.
19. Fulla J, Small A, Kaplan-Marans E, et al. Magnetic-assisted robotic and laparoscopic renal surgery: initial clinical experience with the Levita magnetic surgical system. J Endourol. 2020;34:1242–1246.
20. Huang SF, Welsh LK, Davalos G, et al. Robotic assisted prostatectomy with magnetic retraction. Urol Pract. 2020;7:391–396.
21. Barajas-Gamboa JS, Huidobro F, Jensen J, et al. First in-human experience with a novel robotic platform and magnetic surgery system. Int J Med Robot. 2021;17:1–7.
22. Vargas-Palacios A, Hulme C, Veale T, et al. Systematic review of retraction devices for laparoscopic surgery. Surg Innov. 2016;23:90–101.
23. Fuller J, Ashar BS, Carey-Corrado J. Trocar-associated injuries and fatalities: an analysis of 1399 reports to the FDA. J Minim Invasive Gynecol. 2005;12:302–307.
24. Tonouchi H, Ohmori Y, Kobayashi M, et al. Trocar site hernia. Arch Surg. 2004;139:1248–1256.
25. Welsh LK, Davalos G, Diaz R, et al. Magnetic liver retraction decreases postoperative pain and length of stay in bariatric surgery compared to Nathanson device. J Laparoendosc Adv Surg Tech. 2021;31:194–202.
26. van Beuzekom M, Boer F, Akerboom S, et al. Patient safety in the operating room: an intervention study on latent risk factors. BMC Surg. 2012;12:10.
27. Gifford RW. Primum non nocere. JAMA. 1977;238:589–590.
28. Tamhankar AP, Kelty CJ, Jacob G. Retraction-related liver lobe necrosis after laparoscopic gastric surgery. JSLS. 2011;15:117–121.
