Ewout A. Arkenbout

A state of the art review and categorization of multi-branched instruments for NOTES and SILS

BackgroundSince the advent of Natural Orifice Translumenal Endoscopic Surgery (NOTES) and single incision laparoscopic surgery (SILS), a variety of multitasking platforms have been under development with the objective to allow for bimanual surgical tasks to be performed. These instruments show large differences in construction, enabled degrees of freedom (DOF), and control aspects.MethodsThrough a literature review, the absence of an in-depth analysis and structural comparison of these instruments in the literature is addressed. All the designed and prototyped multitasking platforms are identified and categorized with respect to their actively controlled DOF in their shafts and branches. Additionally, a graphical overview of patents, bench test experiments, and animal and/or human trials performed with each instrument is provided.ResultsThe large range of instruments, various actuation strategies, and different direct and indirect control methods implemented in the instruments show that an optimal instrument configuration has not been found yet. Moreover, several questions remain unanswered with respect to which DOF are essential for bimanual tasks and which control methods are best suited for the control of these DOF.ConclusionsConsidering the complexity of the currently prototyped and tested instruments, future NOTES and SILS instrument development will potentially necessitate a reduction of the available DOF to minimize the control complexity, thereby allowing for single surgeon bimanual task execution.

Robust Hand Motion Tracking through Data Fusion of 5DT Data Glove and Nimble VR Kinect Camera Measurements

Vision based interfaces for human computer interaction have gained increasing attention over the past decade. This study presents a data fusion approach of the Nimble VR vision based system, using the Kinect camera, with the contact based 5DT Data Glove. Data fusion was achieved through a Kalman filter. The Nimble VR and filter output were compared using measurements performed on (1) a wooden hand model placed in various static postures and orientations; and (2) three differently sized human hands during active finger flexions. Precision and accuracy of joint angle estimates as a function of hand posture and orientation were determined. Moreover, in light of possible self-occlusions of the fingers in the Kinect camera images, data completeness was assessed. Results showed that the integration of the Data Glove through the Kalman filter provided for the proximal interphalangeal (PIP) joints of the fingers a substantial improvement of 79% in precision, from 2.2 deg to 0.9 deg. Moreover, a moderate improvement of 31% in accuracy (being the mean angular deviation from the true joint angle) was established, from 24 deg to 17 deg. The metacarpophalangeal (MCP) joint was relatively unaffected by the Kalman filter. Moreover, the Data Glove increased data completeness, thus providing a substantial advantage over the sole use of the Nimble VR system.

Assessing basic "physiology" of the morcellation process and tissue spread: a time-action analysis.

STUDY OBJECTIVE To assess the basic morcellation process in laparoscopic supracervical hysterectomy (LSH). Proper understanding of this process may help enhance future efficacy of morcellation regarding the prevention of tissue scatter. DESIGN Time-action analysis was performed based on video imaging of the procedures (Canadian Task Force classification II-2). SETTING Procedures were performed at Leiden University Medical Centre and St Lucas Andreas Hospital, Amsterdam, the Netherlands. PATIENTS Women undergoing LSH for benign conditions. INTERVENTIONS Power morcellation of uterine tissue. MEASUREMENTS AND MAIN RESULTS The morcellation process was divided into 4 stages: tissue manipulation, tissue cutting, tissue depositing, and cleaning. Stages were timed, and perioperative data were gathered. Data were analyzed as a whole and after subdivision into 3 groups according to uterine weight: <350 g, 350 to 750 g, and >750 g. A cutoff point was found at a uterine weight of 350 g, after which an increase in uterine weight did not affect the cleaning stage. The tissue strip cutting time was used as a measure for tissue strip length. With progression of the morcellation process, the tissue strip cutting time decreases. The majority of cutting time is of short duration (i.e., 60% of the cutting lasts 5 seconds or less), and these occur later on in the morcellation process. CONCLUSION With the current power morcellators, the amount of tissue spread peaks and is independent of uterine weight after a certain cutoff point (in this study 350 g). There is a relative inefficiency in the rotational mechanism because mostly small tissue strips are created. These small tissue strips occur increasingly later on in the procedure. Because small tissue strips are inherently more prone to scatter by the rotational mechanism of the morcellator, the risk of tissue spread is highest at the end of the morcellation procedure. This means that LSH and laparoscopic hysterectomy procedures may be at higher risk for tissue scatter than total laparoscopic hysterectomy. Finally, engineers should evaluate how to create only large tissue strips or assess alternatives to the rotational mechanism.

Design of an endovascular morcellator for the surgical treatment of equine Cushing's disease.

Background: A new paradigm of surgical treatment of equine Cushings disease has been developed using the vascular system combined with a flexible morcellation instrument to reach the pituitary gland. Objective: The goal was twofold: (1) to design, prototype, and test an instrument that can reach the pituitary gland using the vascular system unique to equids and (2) to test the feasibility of the endovascular approach. Animals and methods: The morcellator consists of a radial rotating cutting blade for tissue resection, a flexible shaft incorporating a cable drive for flexible actuation, and central morcellated tissue transportation lumen. The morcellator prototype was tested on a horses cadaver head for the validation of the cutting blade design, actuator design, and feasibility of the endovascular approach. Results: The overall assembled length of the morcellator tip was 13.9 mm, allowing for non-traumatic steering through the vascular system from the proximal end. The radially rotating cutting blade (barrel of Ø 4 and 4.4 mm width) incorporated multiple cutting edges to deliver the action force during resection and provides the necessary grasping force to draw the tissue towards the second cutting edge of the morcellator incorporated inside the blunted cuboidal static tip element (5 mm square and wall-thickness of 0.3 mm). In the tests, the morcellator was successfully guided towards the pituitary and managed to sample pituitary tissue. Conclusion and clinical importance: Continued development of the prototype and the endovascular approach may in time improve the outcome and quality of life of horses suffering from Cushings disease.

Minimally invasive surgical instruments with an accessory channel capable of integrating fibre-optic cable for optical biopsy: a review of the state of the art.

This review article provides a comprehensive overview and classification of minimally invasive surgical instruments with an accessory channel incorporating fibreoptics or another auxiliary device for various purposes. More specifically, this review was performed with the focus on the newly emerging field of optical biopsy, its objective being to discuss primarily the instruments capable of carrying out the optical biopsy and subsequent tissue resection. Instruments housing the fibreoptics for other uses, as well as instruments with an accessory channel capable of housing the fibreoptics instead of their original auxiliary device after relevant design modifications, supplement the review. The entire Espacenet and Scopus databases were searched, yielding numerous patents and articles on conceptual and existing instruments satisfying the criteria. The instruments were categorised based on the function the fibreoptics or the auxiliary device serves. On the basis of their geometrical placement with respect to the tissue resector or manipulator, the subcategories were further defined. This subdivision was used to identify the feasibility of performing the optical biopsy and the tissue resection in an accurate and successive fashion. In general, the existing concepts or instruments are regarded as limited with regard to such a functionality, either due to the placement of their accessory channel with or without the fibreoptics or due to the operational restrictions of their tissue manipulators. A novel opto-mechanical biopsy harvester, currently under development at Delft University of Technology, is suggested as a promising alternative, ensuring a fast and accurate succession of the optical and the mechanical biopsies of a flat superficial tissue.

A Comparitive Overview of Existing and Experimental Morcellators in Gynecology and Urology

https://medicaldevices.asmedigitalcollection.asme.org on 12/05/2018 Terms of U the market, and they are used fairly frequently, it is important to know whether the devices perform optimally, or if one is more functional than another. To this purpose, a literature research has been performed to find all previous, current and experimental morcellators and compare their morcellation rates g/min , i.e., the removed mass divided by its removal time. The instruments were categorized by their respective working principles and significant trends were identified in the field of morcellation from the found and calculated data. The main findings are that the newest morcellators on the market, which rely on the principle of “motor peeling,” are indeed the fastest in terms of morcellation rate, yet it seems that improvements are still possible when it comes to speed and safety. Based on literature, these improvements include the use of an endoscopic bag with a custom created environment and the optimization of the continuity of the applied morcellation working principle.

A gesture-based design tool : Assessing 2DOF vs. 4DOF steerable instrument control

Iterative prototyping is costly and time-consuming. Particularly when designing medical instruments, human factors related design choices significantly impact performance and safety. A tool is presented that allows for the evaluation of steerable instrument controls before the onset of the prototyping stage. The design tool couples gestural input to virtually simulated instrument motions using hand motion tracking. We performed a human-subject evaluation of two manual control strategies that differed in their degrees of freedom (DOF). 2DOF thumb control was compared to 4DOF thumb-index finger control. Results identified regions within the instrument workspace that are difficult to reach and showed participants to favor using the thumb for gross and fine-tuning motions at both control strategies. Index finger ab/adduction was found to be least functional. A strong learning effect was observed at 4DOF control. Based on the results, gesture-based instrument design is a viable design tool.

The Art of Electrosurgery: Trainees and Experts:

The benefits of electrosurgery have been acknowledged since the early 1920s, and nowadays more than 80% of surgical procedures involve devices that apply energy to tissues. Despite its widespread use, it is currently unknown how the operator’s choices with regard to instrument selection and application technique are related to complications. As such, the manner in which electrosurgery is applied can have a serious influence on the outcome of the procedure and the well-being of patients. The aim of this study is to investigate the variety of differences in usage of electrosurgical devices. Our approach is to measure these parameters to provide insight into application techniques. A sensor was developed that records the magnitude of electric current delivered to an electrosurgical device at a frequency of 10 Hz. The sensor is able to detect device activation times and a reliable estimate of the power-level settings. Data were recorded for 91 laparoscopic cholecystectomies performed by different surgeons and residents. Results of the current measurement data show differences in the way electrosurgery is applied by surgeons and residents during a laparoscopic cholecystectomy. Variations are seen in the number of activations, the activation time, and the approach for removal of the gallbladder. Analysis showed that experienced surgeons have a longer activation time than residents (3.01 vs 1.41 seconds, P < .001) and a lower number of activations (102 vs 123). This method offers the opportunity to relate application techniques to clinical outcome and to provide input for the development of a best practice model.

Review of Techniques to Achieve Optical Surface Cleanliness and Their Potential Application to Surgical Endoscopes

A clear visualization of the operative field is of critical importance in endoscopic surgery. During surgery the endoscope lens can get fouled by body fluids (eg, blood), ground substance, rinsing fluid, bone dust, or smoke plumes, resulting in visual impairment. As a result, surgeons spend part of the procedure on intermittent cleaning of the endoscope lens. Current cleaning methods that rely on manual wiping or a lens irrigation system are still far from ideal, leading to longer procedure times, dirtying of the surgical site, and reduced visual acuity, potentially reducing patient safety. With the goal of finding a solution to these issues, a literature review was conducted to identify and categorize existing techniques capable of achieving optically clean surfaces, and to show which techniques can potentially be implemented in surgical practice. The review found that the most promising method for achieving surface cleanliness consists of a hybrid solution, namely, that of a hydrophilic or hydrophobic coating on the endoscope lens and the use of the existing lens irrigation system.

A laparoscopic morcellator redesign to constrain tissue using integrated gripping teeth

Laparoscopic hysterectomy is a procedure that involves the removal of the uterus through an abdominal keyhole incision. Morcellators have been specifically designed for this task, but their use has been discouraged by the food and drug administration (FDA) since November 2014 because of risks of cancerous tissue spread. The use of laparoscopic bags to catch and contain tissue debris has been suggested, but this does not solve the root cause of tissue spread. The fundamental problem lies in the tendency of the tissue mass outside the morcellation tube to rotate along with the cutting blade, causing tissue to be spread through the abdomen. This paper presents a bio-inspired concept that constrains the tissue mass in the advent of its rotation in order to improve the overall morcellation efficacy and reduce tissue spread. A design of gripping teeth integrated into the inner diameter of the morcellation tube is proposed. Various tooth geometries were developed and evaluated through an iterative process in order to maximize the gripping forces of these teeth. The maximum gripping force was determined through the measurement of force-displacement curves during the gripping of gelatin and bovine tissue samples. The results indicate that a tooth ring with a diameter of 15mm can provide a torque resistance of 1.9 Ncm. Finally, a full morcellation instrument concept design is provided.