Richard Bergs

Trocar-less Instrumentation for Laparoscopy: Magnetic Positioning of Intra-abdominal Camera and Retractor

Objective:To develop a novel laparoscopic system of moveable instruments that are positioned intra-abdominally and “locked” into place by external permanent magnets placed on the abdomen. Summary Background Data:In conventional laparoscopy, multiple trocars are required because of the limited degrees of freedom of conventional instrumentation, and the limited working envelope (an inverted cone) created by the fulcrum motion around each port. While robotic systems can improve the number of degrees of freedom, they are restricted by even smaller working envelopes. Methods:A collaborative research group from the Department of Urology and the Automation & Robotics Research Institute of the University of Texas, Arlington built a prototype system of magnetically anchored instruments for trocar-less laparoscopy. The only design mandate was that the developed technology be able to pass into the abdomen through one existing 12-mm diameter trocar. Results:A transabdominal “magnetic anchoring and guidance system” (MAGS) platform was developed to incorporate instruments, retractors, and a controllable intra-abdominal camera. In vitro, the platform was able to anchor 375 and 147 g across porcine tissue 1.8 and 2.5 cm thick, respectively. The permanent magnet platforms were sufficiently strong to retract the porcine liver and securely anchor the camera. Its versatility was demonstrated by moving the camera to virtually any location in the peritoneum with no working envelope restrictions and the subsequent completion of porcine laparoscopic procedures with 2 trocars only. Conclusions:Trocar-less laparoscopy using magnetically anchored instruments is feasible and may expand intracorporeal instrument manipulation substantially beyond current-day capability. The ability to reduce the number of trocars necessary for laparoscopic surgery has the potential to revolutionize surgical practice.

Complete transvaginal NOTES nephrectomy using magnetically anchored instrumentation.

BACKGROUND AND PURPOSE Evolution of minimally invasive techniques has prompted interest in natural orifice transluminal endoscopic surgery (NOTES). Challenges for NOTES include loss of instrument rigidity, reduction in working envelopes, and collision of instrumentation. Magnetic anchoring and guidance system (MAGS) is one surgical innovation developed at our institution whereby instruments that are deployed intra-abdominally are maneuvered by the use of an external magnet. We present our initial animal experience with complete transvaginal NOTES nephrectomy using MAGS technology. MATERIALS AND METHODS Transvaginal NOTES nephrectomy was performed in two female pigs through a vaginotomy, using a 40-cm dual-lumen rigid access port inserted into the peritoneal cavity. A MAGS camera and cauterizer were deployed through the port and manipulated across the peritoneal surface by way of magnetic coupling via an external magnet. A prototype 70-cm articulating laparoscopic grasper introduced through the vaginal access port facilitated dissection after deployment of the MAGS instruments. The renal artery and vein were stapled en-bloc using an extra-long articulating endovascular stapler. RESULTS NOTES nephrectomies were successfully completed in both pigs without complications using MAGS instrumentation. The MAGS camera provided a conventional umbilical perspective of the kidney; the cauterizer, transvaginal grasper, and stapler preserved triangulation while avoiding instrument collisions. Operative duration for the two cases was 155 and 125 minutes, and blood loss was minimal. CONCLUSIONS NOTES nephrectomy using MAGS instrumentation is feasible. We believe this approach improves shortcomings of previously reported NOTES nephrectomies in that triangulation, instrument fidelity, and visualization are preserved while hilar ligation is performed using a conventional stapler without need for additional transabdominal trocars.

Enhancement of EAP actuated facial expressions by designed chamber geometry in elastomers

In this paper, the authors explore various ways that designed chambering of elastomers can enhance electroactive polymer (EAP) actuation. Such enhancements include structuring of chambers for various mechanical functions and advantages, boosting of surface area of a polymer for enhanced ionic migration, construction of advanced electret foams for sensing and for tunable hydrophobicity for micro/pumping action, and distribution of composite EAP devices throughout the chambered elastomer to achieve discrete controllability of electroactive polymer actuators. The authors also discuss the chambering of EAP materials themselves for enhanced actuation effects. With varied design of the chambers of the elastomer, the mechanical and structural properties of the elastomer can be tuned to greatly enhance EAP actuation. The chambers can be designed in accordion-like bellows to achieve extreme elongation with low forces, in spiral geometries to effect negative or neutral poissons ratio under actuation, and with embedded fluidic bellows for fluidic actuation or sensing. These are but a few examples of the advantages that can be achieved via designed chambering of elastomers. The authors also discuss various application uses of the described chambering technologies. Such chambered elastomers, combined with advanced muscle-like actuators, can substantially benefit facelike robots (useful for entertainment and education etc), prosthetics, and numerous modalities of bio-inspired locomotion. In the efforts of the authors to generate facial expression robots with low-power lightweight actuators is described.

Magnetic field anomaly detector using magnetoelectric composites

This study reports the low frequency magnetoelectric (ME) response of the sintered composites comprising of a piezoelectric phase Pb(Zr0.52Ti0.48)O3 (PZT) and magnetostrictive phases NiFe1.9Mn0.1O4 (NFM) and Ni0.8Zn0.2Fe2O4 (NZF) with varying ferrite contents of 3, 5, 10, 15, and 20mol%. It was found that the ME coefficient for the PZT-NZF samples shows considerably less scattering as a function of frequency and the composition 0.8PZT-0.2NZF exhibited a flat response in the range of 10–100Hz with a magnitude of 220mV∕cmOe. This composition was used to design the magnetic field anomaly detector mounted in front of a global positioning system (GPS) controlled vehicle. The results from the vehicle test clearly demonstrate the feasibility of using sintered ME composites for magnetic field detection in the noisy environment.

Live video manipulator for endoscopy and natural orifice transluminal endoscopic surgery (with videos)

BACKGROUND During fluoroscopy, radiologists and gastroenterologists are able to manipulate live fluoroscopic video for better orientation and visualization. During endoscopy and natural orifice transluminal endoscopic surgery (NOTES), this function is not currently available. Particularly during NOTES, the endoscopic image is sometimes inverted, and off-axis operation is required. OBJECTIVE Our purpose was to develop and test a prototype live video manipulator (LVM) for endoscopy, laparoscopy, and NOTES. DESIGN Prospective ex vivo and in vivo feasibility study. INTERVENTIONS We developed a prototype LVM software for video image manipulation that can be easily installed on any computer. The video input is streamed into the computer and can be displayed on a standard monitor. LVM was tested ex vivo in the following functions: (1) instant live video rotation, (2) vertical or horizontal video inversion, (3) mirror imaging, and (4) digital zooming. These functions were also tested during upper and lower GI endoscopy, ERCP, diagnostic laparoscopy, and various transvaginal NOTES procedures (cholecystectomy, gastroenterostomy, and sleeve gastrectomy) in porcine models. MAIN OUTCOME MEASUREMENTS Image quality observation between unmanipulated and manipulated live videos. RESULTS LVM reliably and easily performed live video manipulation during these tests. Besides standard definition video signals, LVM is fully compatible with high-definition video endoscopy. Three observers reported that the subjective image quality was the same in specified areas between manipulated and unmanipulated live videos. LIMITATIONS Observation and feasibility study. CONCLUSIONS LVM reliably and conveniently performed live video manipulations. LVM requires minimal equipment, capital investment, and maintenance, and is easy to set up. LVM can be a useful tool in many medical imaging studies, including endoscopy, laparoscopy, and NOTES, either as a built-in technology or as an as-needed add-on feature.

A Randomized Comparison of Laparoscopic, Flexible Endoscopic, and Wired and Wireless Magnetic Cameras on Ex Vivo and In Vivo NOTES Surgical Performance

Background. The influence of endoscopic video camera (VC) image quality on surgical performance has not been studied. Flexible endoscopes are used as substitutes for laparoscopes in natural orifice translumenal endoscopic surgery (NOTES), but their optics are originally designed for intralumenal use. Manipulable wired or wireless independent VCs might offer advantages for NOTES but are still under development. Objective. To measure the optical characteristics of 4 VC systems and to compare their impact on the performance of surgical suturing tasks. Methods. VC systems included a laparoscope (Storz 10 mm), a flexible endoscope (Olympus GIF 160), and 2 prototype deployable cameras (magnetic anchoring and guidance system [MAGS] Camera and PillCam). In a randomized fashion, the 4 systems were evaluated regarding standardized optical characteristics and surgical manipulations of previously validated ex vivo (fundamentals of laparoscopic surgery model) and in vivo (live porcine Nissen model) tasks; objective metrics (time and errors/precision) and combined surgeon (n = 2) performance were recorded. Results. Subtle differences were detected for color tests, and field of view was variable (65°-115°). Suitable resolution was detected up to 10 cm for the laparoscope and MAGS camera but only at closer distances for the endoscope and PillCam. Compared with the laparoscope, surgical suturing performances were modestly lower for the MAGS camera and significantly lower for the endoscope (ex vivo) and PillCam (ex vivo and in vivo). Conclusions. This study documented distinct differences in VC systems that may be used for NOTES in terms of both optical characteristics and surgical performance. Additional work is warranted to optimize cameras for NOTES. Deployable systems may be especially well suited for this purpose.

Development of a Transabdominal Anchoring System for Trocar-Less Laparoscopic Surgery

Compared with open surgery, laparoscopy results in significantly less pain, faster convalescence, and less morbidity. However, eye-hand dissociation, a two-dimensional field-of-view and fixed instrumentation with limited degrees of freedom contribute to a steep learning curve and demanding dexterity requirements for many laparoscopic procedures. One of the main limitations of laparoscopy is the fixed working envelope surrounding each trocar, often necessitating placement of multiple ports to accomodate changes in position of the instruments or laparoscope to improve visibility and efficiency. The placement of additional working ports contributes to post-operative pain and carries a small risk of bleeding or adjacent organ damage. In order to provide for greater flexibility of endoscopic viewing and instrument usage and to further reduce morbidity, a novel adjunct laparoscopic system has been developed consisting of a platform capable of supporting various laparoscopic tools which is secured magnetically to the abdominal wall and subsequently positioned within the abdominal cavity through surgeon-controlled, external magnetic couples on the patient’s abdomen. Using this technique, instruments such as miniature endoscopic cameras used to augment the surgical field of view and surgical retractors have been successfully evaluated in a dry laboratory as well as in porcine models, with several others currently under investigation. This document elaborates on the theoretical and empirical process which has led to anchoring designs optimized for size, strength and surgical compatibility, as well as the benefits, limitations and prospects for the use of incisionless, magnetically-coupled tooling in laparoscopic surgery.Copyright

Magnetically Anchored Cautery Dissector Improves Triangulation, Depth Perception, and Workload During Single-Site Laparoscopic Cholecystectomy

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

Minimizing MIS Using Magnetically Anchored and Percutaneous Needlescopic Instruments for Basic and Complex Procedures

The stem cell spheroids were infected with NV1066, a third-generation herpesvirus, or NDV-F3aa-GFP, a Newcastle Disease virus mutant. Both viruses carried the marker gene green fluorescent protein (GFP), which allowed monitoring by fluorescent microscopy. Cell cycle analysis and cell migration assay were also performed. Results: Viral infection of cancer stem cells was rapid (GFP expression was seen by 24 hours). The viruses from both families each produced efficient infection and killing of cancer. At doses of multiplicity of infection (MOI, number of viruses per tumor cell) of 0.5 or 1, >95% of cells were dead by day 6. Infection with virus also produced decreased migratory capacity of the cancer stem cells and shifted the population to a higher fraction in S phase. Conclusion: Multiple types of oncolytic viruses effectively target the stem cell subpopulation of pancreatic cancer cells. Infection decreases metastatic potential and effects killing of such stem cells. These data support clinical studies of oncolytic viruses in the treatment of chemoand radioresistant tumors.

607 Magnetic Cautery Dissector for Single Site Laparoscopic Cholecystectomy in a Cadaver Model

The Magnetic Anchoring and Guidance System (MAGS) consists of an internal surgical device coupled across the abdominal wall and manipulated using an external handheld magnet. This video demonstrates a MAGS cautery dissector used in a cadaveric human cholecystectomy model. The gallbladder was retracted percutaneously and one laparoscopic instrument was used for assistance. The MAGS instrument was used to perform the entire dissection (18 minutes). The MAGS dissector provided excellent triangulation, obviated the need for additional laparoscopic instruments, minimized instrument conflicts, was compatible with human anatomical considerations, and greatly facilitated the single site approach.