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.

Power Morcellator Features Affecting Tissue Spill in Gynecologic Laparoscopy: An In-Vitro Study.

STUDY OBJECTIVE: To assess features of power morcellators (blade diameter, circular vs oscillating cutting, blade rotation speed, experience level) regarding their effect on the amount of tissue spill. In addition, the amount of tissue spill after the initial two-thirds and final one-third of the morcellated specimen was evaluated. DESIGN: In vitro study (Canadian Task Force classification II-2). SETTING: Laparoscopic skills lab of an academic hospital. PATIENTS: Not applicable. INTERVENTION: Power morcellation of beef tongue specimens. MEASUREMENTS AND MAIN RESULTS: Twenty-four trials were performed. Morcellation was performed in 2 phases (phase 1: initial two-thirds of the total tissue; phase 2: last one-third of the tissue). With larger blade diameter a decline was observed in both the weight of the spilled particles (phase 1) and the number of spilled particles (phases 1 and 2 and both combined) (weight phase 1: 6.5 g vs 6.3 g vs 2.2 g for 12.5 mm vs 15 mm vs 20 mm, respectively, p = .04; number particles: phase 1, 10.2 vs 7.2 vs 2.7, p = .01; phase 2, 22.9 vs 19.0 vs 8.9, p = .02; total, 34.7 vs 26.2 vs 11.6, p = .01). Also, spinning of the tissue mass due to torque applied by the rotating blade occurred later when blade size increased, and the size of the spilled particles was larger (weight of morcellated tissue at onset of torque: 136 g vs 198 g vs 222 g, p = .07; size: .6 g vs .9 g vs .8 g, p = .1). In the oscillation mode there was less total spill (6.8 g/100 g vs 21.3 g/100 g, p = .01, for oscillation and circular cutting, respectively). CONCLUSION: The present study demonstrates that less spill is created by power morcellators with an oscillating blade and/or a large diameter (≥20 mm). Furthermore, when using a large-diameter blade the spilled particles are larger, and less morcellation repetitions are needed. By combining these features with currently introduced contained morcellation, the safety of the morcellation process with respect to tissue spill can be further improved.

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

BACKGROUND: Since 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. METHODS: Through 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. RESULTS: The 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. CONCLUSIONS: Considering 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.

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.

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.

Electromechanical morcellators in minimally invasive gynecologic surgery: an update.

STUDY OBJECTIVE: To assess all electromechanical morcellators used in gynecology to achieve an objective comparison between them and to make suggestions for improvements in future developments. DESIGN: Literature review. INTERVENTION: The PubMed, Web of Science, EMBASE, and MAUDE databases were systematically searched for all available literature using the terms "morcellator," "morcellators," "morcellate," "morcellation," and "morcellated." All articles with information on morcellation time and morcellated tissue mass or the calculated morcellation rate of electromechanical morcellators used for gynecologic laparoscopic surgery were included. For general data of an existing morcellator, the manufacturer was contacted and Google was searched. Data for morcellation rate, type of procedure, and general characteristics were compared. MEASUREMENTS AND MAIN RESULTS: Seven articles were suitable for analysis, and 11 different morcellators were found. In the past decades the morcellation rate has increased. The described morcellation rate ranged from 6.2 to 40.4 g/min. Motor peeling is currently the fastest working principle. Comparing hysterectomy and myomectomy per device, the Morcellex and Rotocut morcellators demonstrated a higher morcellation rate for myomectomy, 25.9 vs 30 g/min and 28.4 vs 33.1 g/min, respectively, although the X-Tract morcellator showed a higher rate for hysterectomy, 14.2 vs 11.7 g/min. CONCLUSION: Over the years, the morcellator has improved with respect to the morcellation rate. However, the morcellation process still has limitations, including tissue scattering, morcellator-related injuries, and the inevitable small blade diameter, which all come at the expense of the morcellation rate and time. Therefore, development of improved morcellators is required, with consideration of the observed limitations.

Catheter steering in interventional cardiology: Mechanical analysis and novel solution.

In recent years, steerable catheters have been developed to combat the effects of the dynamic cardiac environment. Mechanically actuated steerable catheters appear the most in the clinical setting; however, they are bound to a number of mechanical limitations. The aim of this research is to gain insight in these limitations and use this information to develop a new prototype of a catheter with increased steerability. The main limitations in mechanically steerable catheters are identified and analysed, after which requirements and solutions are defined to design a multi-steerable catheter. Finally, a prototype is built and a proof-of-concept test is carried out to analyse the steering functions. The mechanical analysis results in the identification of five limitations: (1) low torsion, (2) shaft shortening, (3) high unpredictable friction, (4) coupled tip-shaft movements, and (5) complex cardiac environment. Solutions are found to each of the limitations and result in the design of a novel multi-steerable catheter with four degrees of freedom. A prototype is developed which allows the dual-segmented tip to be steered over multiple planes and in multiple directions, allowing a range of complex motions including S-shaped curves and circular movements. A detailed analysis of limitations underlying mechanically steerable catheters has led to a new design for a multi-steerable catheter for complex cardiac interventions. The four integrated degrees of freedom provide a high variability of tip directions, and repetition of the bending angle is relatively simple and reliable. The ability to steer inside the heart with a variety of complex shaped curves may potentially change conventional approaches in interventional cardiology towards more patient-specific and lower complexity procedures. Future directions are headed towards further design optimizations and the experimental validation of the prototype.

HelixFlex: bioinspired maneuverable instrument for skull base surgery.

Endoscopic endonasal surgery is currently regarded as the 'gold standard' for operating on pituitary gland tumors, and is becoming more and more accepted for treatment of other skull base lesions. However, endoscopic surgical treatment of most skull base pathologies, including certain pituitary tumors, is severely impaired by current instruments lack of maneuverability. Especially, gaining access to, and visibility of, difficult-to-reach anatomical corners without interference with surrounding neurovascular structures or other instruments, is a challenge. In this context there is the need for instruments that are able to provide a stable shaft position, while both the orientation and the position of the end-effector can be independently controlled. Current instruments that allow for this level of maneuverability are usually mechanically complex, and hence less suitable for mass production. This study therefore focuses on the development of a new actuation technique that allows for the required maneuverability while reducing the construction complexity. This actuation technique, referred to as multi-actuation, integrates multiple cable routings into a single steerable structure. Multi-actuation has been successfully integrated and tested in a handheld prototype instrument called HelixFlex. HelixFlex contains a 4 degrees of freedom maneuverable 5.8 mm (diameter) tip and shows promising results concerning its maneuverability and potential rigidity.

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.