Image Guided Interpedicular Screw Placement Simulation System for Training and Skill Evaluation. Proof of Concept.

BACKGROUND: The SpineST-01 system is an image-guided vertebrae cannulation training system. During task execution, the computer calculates performance-based metrics displaying different visual perspectives (lateral view, axial view, anteroposterior view) with the position of the instrument inside the vertebra. Finally, a report with the metrics is generated as performance feedback. METHODS: A training box holds a 3D printed spine section. The computer works with 2 orthogonally disposed cameras, tracking passive markers placed on the instrument. Eight metrics were proposed to evaluate the execution of the surgical task. A preliminary study with 25 participants divided into 3 groups (12 novices, 10 intermediates, and 3 expert) was conducted to determine the feasibility of the system and to evaluate and assess the performance differences of each group using Kruskal-Wallis analysis and Mann-Whitney U analysis. In both analyses, a P value ≤ 0.05 was considered statistically significant. RESULTS: When comparing experts versus novices and all 3 groups, statistical analysis showed significant differences in 6 of the 8 metrics: axial angle error (°), lateral angle error (°), average speed (mm/second), progress between shots (mm), Time (seconds), and shots. The metrics that did not show any statistically significant difference were time between shots (seconds), and speed between shots (mm/second). Also, the average result comparison placed the experts as the best performance group. CONCLUSIONS: Initial testing of the SpineST-01 demonstrated potential for the system to practice image-guided cannulation tasks on lumbar vertebrae. Results showed objective differences between experts, intermediates, and novices in the proposed metrics, making this system a feasible option for developing basic navigation system skills without the risk of radiation exposure and objectively evaluating task performance.

Objective Evaluation of Laparoscopic Experience Based on Muscle Electromyography and Accelerometry Performing Circular Pattern Cutting Tasks: A Pilot Study.

Purpose.The aim of this work is to present a new physical laparoscopy simulator with an electromyography (EMG)/accelerometry-based muscle activity recording system, EvalLap EMG-ACC, and perform objective evaluation of laparoscopic skills based on the quantification of muscle activity of participants with different levels of laparoscopic experience. Methods. EMG and ACC signals were obtained from 14 participants (6 experts, 8 medical students) performing circular pattern cutting tasks using a laparoscopic box trainer with the Trigno (Delsys Inc, Natick, MA) portable wireless system of 16 wireless sensors. Sensors were placed on the proximal and distal muscles of the upper extremities. Seven evaluation metrics were proposed and compared between skilled and novice surgeons. Results. The proximal and distal arm muscles (trapezius, deltoids, biceps, and forearms) were most active while executing laparoscopic tasks. Laparoscopic experience was associated with differences in EMG amplitude (Aavg), muscle activity (iEMG), hand acceleration (iACH), user movement (iAC), and muscle fatigue. For the cutting task, the deltoid, bicep, forearm EMG amplitude, and user movement significantly differed between experience groups. Conclusion. This pilot study demonstrates that different muscle groups are preferentially activated during laparoscopic tasks depending on the level of surgical experience. Expert surgeons showed less muscle activity compared with novices. EvalLap EMG-ACC represents a promising means to distinguish surgeons with basic cutting skills from those who have not yet developed these skills.

Objective classification of psychomotor laparoscopic skills of surgeons based on three different approaches.

BACKGROUND: The determination of surgeons' psychomotor skills in minimally invasive surgery techniques is one of the major concerns of the programs of surgical training in several hospitals. Therefore, it is important to assess and classify objectively the level of experience of surgeons and residents during their training process. The aim of this study was to investigate three classification methods for establishing automatically the level of surgical competence of the surgeons based on their psychomotor laparoscopic skills. METHODS: A total of 43 participants, divided into an experienced surgeons group with ten experts (> 100 laparoscopic procedures performed) and non-experienced surgeons group with 24 residents and nine medical students (< 10 laparoscopic procedures performed), performed three tasks in the EndoViS training system. Motion data of the instruments were captured with a video-tracking system built into the EndoViS simulator and analyzed using 13 motion analysis parameters (MAPs). Radial basis function networks (RBFNets), K-star (K*), and random forest (RF) were used for classifying surgeons based on the MAPs' scores of all participants. The performance of the three classifiers was examined using hold-out and leave-one-out validation techniques. RESULTS: For all three tasks, the K-star method was superior in terms of accuracy and AUC in both validation techniques. The mean accuracy of the classifiers was 93.33% for K-star, 87.58% for RBFNets, and 84.85% for RF in hold-out validation, and 91.47% for K-star, 89.92% for RBFNets, and 83.72% for RF in leave-one-out cross-validation. CONCLUSIONS: The three proposed methods demonstrated high performance in the classification of laparoscopic surgeons, according to their level of psychomotor skills. Together with motion analysis and three laparoscopic tasks of the Fundamental Laparoscopic Surgery Program, these classifiers provide a means for objectively classifying surgical competence of the surgeons for existing laparoscopic box trainers.

Construct validity of a video-tracking system based on orthogonal cameras approach for objective assessment of laparoscopic skills.

PURPOSE: This study was aimed to establish the construct validity of a video-tracking system based on orthogonal cameras approach for assessment of laparoscopic psychomotor skills in training environments. METHODS: The camera-tracking system consists of two webcams placed in orthogonal configuration at a distance of 13.5 cm. The orthogonal cameras employ a color segmentation algorithm to register the 3D motions of the laparoscopic instruments using colored tapes placed on the distal end. For construct validity, 31 participants (4 experts and 27 residents) performed three training tasks in a laparoscopic box trainer with the built-in orthogonal cameras system. Eleven motion-related parameters were used to evaluate their performance. Statistical analysis was performed, and results between two groups were compared using a Mann-Whitney U-test. RESULTS: Construct validity results showed statistical differences in almost all motion-related parameters for assessment of laparoscopic technical skills. Results demonstrated that the orthogonal video-based tracking system was able to differentiate laparoscopic experience between experts and trainees surgeons. CONCLUSION: The orthogonal cameras system was successfully validated in a laparoscopic box trainer. This video-based tracking system was able to distinguish performance between experts and trainees surgeons, showing its potential as a reliable tool to assess laparoscopic psychomotor skills. The orthogonal cameras allow incorporating the advantages of this video motion-tracking technology with the benefits of the traditional laparoscopic box trainers, creating realistic haptic feedback and allowing the evaluation of psychomotor skills of the surgeons.

Pediatric inguinal hernia repair with a single-incision approach using an Endo Close™ suturing device.

BACKGROUND: Diverse techniques have been described for pediatric inguinal hernia repair, based on extraperitoneal [1-4] and intraperitoneal [5-8] methodologies. In this video, we describe a novel technique to repair pediatric inguinal hernia using an Endo Close™ suturing device by percutaneous puncture with a single incision. METHODS: With a transumbilical approach, a 5-mm trocar is inserted for a 30° laparoscope. A 3-mm incision is made, and the Endo Close™ suturing device (Covidien, Minneapolis, MN, USA), with a 2-0 polypropylene suture retained by the stylet, is inserted perpendicularly to the skin. An extraperitoneal dissection is made on a side the inguinal ring and the needle of the device penetrates the peritoneum through the inferior border. Then, the stylet mechanism is pushed to free the lasso inside the cavity. At the same incision site, the needle of the Endo Close™ is inserted again, but an extraperitoneal dissection is made on the other side of the ring, ensuring that the needle penetrates at the same exit orifice. Now, the suture lasso is recovered and retracted to close the ring. Finally, the suture is extracted and knots are tied extracorporeally at the level of the skin. RESULTS: A total of 34 patients (20 females and 14 males) underwent surgery with this procedure. Operative time for unilateral repair was 10-15 and 25-30 min for the bilateral repair (29 unilateral/5 bilateral). The patients experienced minimal postoperative pain. The follow-up period was 12 months with no complications, no recurrence and without cases of postoperative hydrocele. There were no injuries to the structures as vessels or vas deferens, and the esthetic outcome was excellent. CONCLUSIONS: The technique presents a simple, safe and reliable method to repair inguinal hernias in children. The long-term results of this novel technique will be evaluated in future studies.

Optimizing the positional relationships between instruments used in laparoscopic simulation using a simple trigonometric method.

BACKGROUND: Various methods for evaluating laparoscopic skill have been reported, but without detailed information on the configuration used they are difficult to reproduce. Here we present a method based on the trigonometric relationships between the instruments used in a laparoscopic training platform in order to provide a tool to aid in the reproducible assessment of surgical laparoscopic technique. MATERIALS AND METHODS: The positions of the instruments were represented using triangles. Basic trigonometry was used to objectively establish the distances among the working ports RL, the placement of the optical port h', and the placement of the surgical target OT. RESULTS: The optimal configuration of a training platform depends on the selected working angles, the intracorporeal/extracorporeal lengths of the instrument, and the depth of the surgical target. We demonstrate that some distances, angles, and positions of the instruments are inappropriate for satisfactory laparoscopy. CONCLUSIONS: By applying basic trigonometric principles we can determine the ideal placement of the working ports and the optics in a simple, precise, and objective way. In addition, because the method is based on parameters known to be important in both the performance and quantitative quality of laparoscopy, the results are generalizable to different training platforms and types of laparoscopic surgery.

Postural mechatronic assistant for laparoscopic solo surgery (PMASS).

BACKGROUND AND PURPOSE: Laparoscopes used in laparoscopic surgery are manipulated by human means, passive systems or robotic systems. All three methods accumulate downtime when the laparoscope is cleaned and the optical perspective is adjusted. This work proposes a new navigation system that autonomously handles the laparoscope, with a view to reducing latency, and that allows real-time adjustment of the visual perspective. METHODS: The system designed is an intuitive mechatronic system with three degrees of freedom and a single active articulation. The system uses the point of insertion as the invariant point for navigation and has a work space that closely resembles an inverted cone. RESULTS: The mechatronic system has been tested in a physical trainer, cutting and suturing chicken parts, as well as in laparoscopic ovariohysterectomies in dogs and pediatric surgeries. In all the procedures, surgeons were able to auto-navigate and there was no visual tremor while using the system. Surgeons performed visual approaches in real time and had both hands free to carry out the procedure. CONCLUSION: This new mechatronic system allows surgeons to perform solo surgery. Cleaning and positioning downtime are reduced, since it is the surgeon him/herself who handles the optics and selects the best visual perspective for the surgery.