Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 19 de 19
Filter
1.
Appl Clin Inform ; 10(1): 140-150, 2019 01.
Article in English | MEDLINE | ID: mdl-30812040

ABSTRACT

OBJECTIVE: The use of text messaging in clinical care has become ubiquitous. Due to security and privacy concerns, many hospital systems are evaluating secure text messaging applications. This paper highlights our evaluation process, and offers an overview of secure messaging functionalities, as well as a framework for how to evaluate such applications. METHODS: Application functionalities were gathered through literature review, Web sites, speaking with representatives, demonstrations, and use cases. Based on similar levels of functionalities, vendors were grouped into three tiers. Essential and secondary functionalities for our health system were defined to help narrow our vendor choices. RESULTS: We stratified 19 secure messaging vendors into three tiers: basic secure communication, secure communication within an existing clinical application, and dedicated communication and collaboration systems. Our essential requirements revolved around functionalities to enhance security and communication, while advanced functionalities were mostly considered secondary. We then narrowed our list of 19 vendors to four, then created clinical use cases to rank the final vendors. DISCUSSION: When evaluating a secure messaging application, numerous factors must be considered in parallel. These include: what clinical processes to improve, archiving text messages, mobile device management, bring your own device policy, and Wi-Fi architecture. CONCLUSION: Secure messaging applications provide a Health Insurance Portability and Accountability Act (HIPAA) compliant communication platform, and also include functionality to improve clinical collaboration and workflow. We hope that our evaluation framework can be used by other health systems to find a secure messaging application that meets their needs.


Subject(s)
Computer Security , Delivery of Health Care/methods , Text Messaging , Humans
2.
Urology ; 121: 175-181, 2018 11.
Article in English | MEDLINE | ID: mdl-30193844

ABSTRACT

OBJECTIVE: To describe long-term quality of life (QOL) outcomes after rectourethral fistula (RUF) repair. RUF is a debilitating diagnosis and complex surgical dilemma with limited data regarding QOL after repair. METHODS: Patients at a tertiary referral center undergoing transperineal RUF repair 1/2009-5/2016 were analyzed. Patients were contacted by telephone to assess QOL following repair. Descriptive analysis performed of short-term surgical data (success and complications) and long-term QOL data (novel questionnaire). RESULTS: Twenty one men underwent RUF surgery with 95% success after initial repair. Fifty two percent had a history of radiation and/or ablation. Four individuals (19%) experienced a Clavien-Dindo complication within 30 days, with 3 of those being grade III+. Fifteen had postoperative urinary incontinence, of whom 73% underwent artificial urinary sphincter placement. Three previously radiated individuals underwent subsequent urethral stricture surgery. At long-term follow-up (mean 45.6 ± 27.1 months), 53% reported perineal pain, 43% reported problems related to the gracilis flap, and 80% reported urinary incontinence (primarily occasional mild leakage). Twenty one percent were unable to do the things they wanted in their daily lives, while 80% reported that surgery positively impacted their life. None would have opted for complete urinary diversion. CONCLUSION: RUF repair leads to patient satisfaction and improved QOL, despite possible residual issues such as perineal pain and urinary incontinence. Definitive RUF repair should be offered to suitable radiated and nonradiated patients.


Subject(s)
Anal Canal/surgery , Fecal Incontinence , Postoperative Complications , Quality of Life , Rectal Fistula , Urinary Fistula , Urinary Incontinence , Adult , Aged , Fecal Incontinence/etiology , Fecal Incontinence/physiopathology , Fecal Incontinence/psychology , Humans , Long Term Adverse Effects/physiopathology , Long Term Adverse Effects/psychology , Male , Middle Aged , Organ Sparing Treatments/methods , Outcome Assessment, Health Care , Postoperative Complications/physiopathology , Postoperative Complications/psychology , Postoperative Period , Plastic Surgery Procedures/adverse effects , Plastic Surgery Procedures/methods , Recovery of Function , Rectal Fistula/diagnosis , Rectal Fistula/etiology , Rectal Fistula/physiopathology , Rectal Fistula/surgery , Retrospective Studies , United States , Urinary Fistula/diagnosis , Urinary Fistula/etiology , Urinary Fistula/physiopathology , Urinary Fistula/surgery , Urinary Incontinence/etiology , Urinary Incontinence/physiopathology , Urinary Incontinence/psychology
3.
Inflamm Bowel Dis ; 23(1): E3, 2017 01.
Article in English | MEDLINE | ID: mdl-28002133
4.
Inflamm Bowel Dis ; 22(8): 1887-95, 2016 08.
Article in English | MEDLINE | ID: mdl-27057681

ABSTRACT

BACKGROUND: Preoperative immunosuppressive use among patients with Crohn's disease or ulcerative colitis may lead to an increased risk of postoperative complications. There is limited information on the preoperative safety profile of methotrexate (MTX) in inflammatory bowel disease (IBD). METHODS: A retrospective study of patients who underwent abdominal surgery for IBD between 1993 and 2012 was performed and records abstracted, including preoperative use of MTX, azathioprine/6-mercaptopurine, antitumor necrosis factor, and corticosteroids. Early postoperative complications, including death, septic, and nonseptic complications were identified. A meta-analysis was also performed on the use of preoperative MTX in patients with IBD or rheumatoid arthritis. RESULTS: A total of 180 patients with IBD underwent abdominal surgery. A total of 15 patients received MTX either monotherapy or in combination therapy. Total early postoperative complications were identified in 71 (39%) patients, specifically 5 patients on oral MTX. A total of 51 cases (28%) of septic complications and 20 (11%) nonseptic. No significant association between the use of MTX and early postoperative complications was found. The odds ratio (OR) of complications versus no complications associated with MTX was 0.75 (95% CI, 0.25-2.29) and with azathioprine/6-mercaptopurine, OR 1.48 (95% CI, 0.77-2.84). The odds of a septic complication associated with MTX were 0.58 (95% CI, 0.09-3.73), and higher in azathioprine/6-mercaptopurine, OR 3.97 (95% CI, 1.03-15.3). Our meta-analysis also did not reveal an increased risk of postoperative complications in IBD or rheumatoid arthritis on preoperative MTX (OR 0.62, 95% CI, 0.34-1.15). CONCLUSIONS: Preoperative MTX use does not seem to be associated with early postoperative complications in IBD.


Subject(s)
Colitis, Ulcerative/drug therapy , Crohn Disease/drug therapy , Immunosuppressive Agents/therapeutic use , Methotrexate/therapeutic use , Postoperative Complications/epidemiology , Adult , Aged , Aged, 80 and over , Arthritis, Rheumatoid/drug therapy , Azathioprine/therapeutic use , Colitis, Ulcerative/surgery , Crohn Disease/surgery , Female , Humans , Male , Mercaptopurine/therapeutic use , Middle Aged , Odds Ratio , Preoperative Period , Retrospective Studies , Sepsis/epidemiology , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Young Adult
5.
J Surg Res ; 192(2): 329-38, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25108691

ABSTRACT

BACKGROUND: Laparoscopic psychomotor skills are challenging to learn and objectively evaluate. The Fundamentals of Laparoscopic Skills (FLS) program provides a popular, inexpensive, widely-studied, and reported method for evaluating basic laparoscopic skills. With an emphasis on training safety before efficiency, we present data that explore the metrics in the FLS curriculum. MATERIALS AND METHODS: A multi-institutional (n = 3) cross-sectional study enrolled subjects (n = 98) of all laparoscopic skill levels to perform FLS tasks in an instrumented box trainer. Recorded task videos were postevaluated by faculty reviewers (n = 2) blinded to subject identity using a modified Objective Structured Assessment of Technical Skills (OSATS) protocol. FLS scores were computed for each completed task and compared with demographically established skill levels (training level and number of procedures), video review scoring, and objective performance metrics including path length, economy of motion, and peak grasping force. RESULTS: Three criteria used to determine expert skill, training and experience level, blinded review of performance by faculty via OSATS, and FLS scores, disagree in establishing concurrent validity for determining "true experts" in FLS tasks. FLS-scoring exhibited near-perfect correlation with task time for all three tasks (Pearson r = 0.99, 1.00, 1.00 with P <0.00000001). FLS error penalties had negligible effect on FLS scores. Peak grasping force did not correlate with task time or FLS scores. CONCLUSIONS: FLS technical skills scores presented negligible benefit beyond the measurement of task time. FLS scoring is weighted more toward speed than precision and may not significantly address poor tissue handling skills, especially regarding excessive grasping force. Categories of experience or training level may not form a suitable basis for establishing proficiency thresholds or for construct validity studies for technical skills.


Subject(s)
Computer-Assisted Instruction/instrumentation , Education, Medical/methods , Laparoscopy/education , Psychomotor Performance , Surgeons/education , Computer-Assisted Instruction/methods , Computer-Assisted Instruction/standards , Education, Medical/standards , Educational Measurement , Humans , Reproducibility of Results , Students, Medical , Suture Techniques/education , Time and Motion Studies , User-Computer Interface
7.
Inflamm Bowel Dis ; 19(10): 2118-24, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23863401

ABSTRACT

BACKGROUND: Obesity is an emerging problem in the care of inflammatory bowel disease (IBD) patients and has been associated with a diminished response to adalimumab. Whether obesity influences the response to infliximab (IFX) is not known. METHODS: A retrospective cohort of 124 subjects with IBD initiating IFX, naive to biologic therapy, was identified. Subjects were stratified according to their weight and body mass index (BMI). The primary outcome was the first occurrence of an IBD flare defined as dose escalation of IFX, corticosteroid use, discontinuation of IFX, hospitalization, or surgery. Multivariable logistic regression was performed considering body mass and BMI as categorical and continuous variables. RESULTS: Obese (BMI > 30 kg/m) patients with Crohn's disease were more likely to have an IBD flare than nonobese patients (adjusted hazard ratio [HR]: 3.03, P < 0.001); overweight (BMI > 25 kg/m) patients with ulcerative colitis trended toward a similar observation (HR: 9.68, P = 0.06). When considered as continuous variables, increasing mass and BMI were associated with earlier IBD flare in both Crohn's disease (adjusted HR: 1.06 per unit increase in BMI [P = 0.02] and 1.02 per kg increase in body mass [P = 0.02]) and ulcerative colitis (adjusted HR: 1.3 per unit increase in BMI [P = 0.01] and 1.11 per kg increase in body mass [P = 0.004]). CONCLUSIONS: Increased body weight is associated with an earlier time to loss of response to IFX in Crohn's disease and ulcerative colitis, a novel finding given that IFX is the only antitumor necrosis factor agent whose dosing reflects increased body weight.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Antibodies, Monoclonal/therapeutic use , Colitis, Ulcerative/drug therapy , Crohn Disease/drug therapy , Obesity/physiopathology , Adult , Body Mass Index , Colitis, Ulcerative/complications , Crohn Disease/complications , Female , Follow-Up Studies , Humans , Infliximab , Male , Prognosis , Retrospective Studies , Time Factors
8.
J Healthc Qual ; 34(5): 39-47; quiz 48-9, 2012.
Article in English | MEDLINE | ID: mdl-22860887

ABSTRACT

To achieve sustainable reductions in healthcare-associated infections (HAIs), the University of Washington Medical Center (UWMC) deployed a collaborative, systems-level initiative. With the sponsorship of senior leadership, multidisciplinary teams were established to address healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA), central-line-associated bloodstream infections (CLABSI), ventilator-associated pneumonia (VAP), and respiratory virus infections. The goal of the initiative was to eliminate these four HAIs among medical center inpatients by 2012. In the first 24 months of the project, the number of healthcare-associated MRSA cases decreased 58%; CLABSI cases decreased 54%. Staff and provider compliance with infection prevention measures improved and remained strong, for example, 96% compliance with hand hygiene, 98% compliance with the recommended influenza vaccination program, and 100% compliance with the VAP bundle. Achieving these results required an array of coordinated, systems-level interventions. Critical project success factors were believed to include creating organizational alignment by declaring eliminating HAIs as an organizational breakthrough goal, having the organization's executive leadership highly engaged in the project, coordination by an experienced and effective project leader and manager, collaboration by multidisciplinary project teams, and promoting transparency of results across the organization.


Subject(s)
Bacteremia/prevention & control , Catheter-Related Infections/prevention & control , Cooperative Behavior , Cross Infection/prevention & control , Infection Control/methods , Methicillin-Resistant Staphylococcus aureus , Pneumonia, Ventilator-Associated/prevention & control , Respiratory Tract Infections/prevention & control , Respiratory Tract Infections/virology , Staphylococcal Infections/prevention & control , Humans , Models, Organizational , Organizational Objectives , Washington/epidemiology
10.
Article in English | MEDLINE | ID: mdl-19964184

ABSTRACT

A teleoperated surgical robotic system allows surgical procedures to be conducted across long distances while utilizing wired and wireless communication with a wide spectrum of performance that may affect the outcome. An open architecture portable surgical robotic system (Raven) was developed for both open and minimally invasive surgery. The system has been the subject of an intensive telesurgical experimental protocol aimed at exploring the boundaries of the system and surgeon performance during a series of field experiments in extreme environments (desert and underwater) teleportation between US, Europe, and Japan as well as lab experiments under synthetic fixed time delay. One standard task (block transfer emulating tissue manipulation) of the Fundamentals of Laparoscopic Surgery (FLS) training kit was used for the experimental protocol. Network characterization indicated a typical time delay in the range of 16-172 ms in field experiments. The results of the lab experiments showed that the completion time of the task as well as the length of the tool tip trajectory significantly increased (alpha< 0.02) as time delay increased in the range of 0-0.5 sec increased. For teleoperation with a time delay of 0.25s and 0.5s the task completion time was lengthened by a factor of 1.45 and 2.04 with respect to no time delay, whereas the length of the tools' trajectory was increased by a factor of 1.28 and 1.53 with respect to no time delay. There were no statistical differences between experienced surgeons and non-surgeons in the number of errors (block drooping) as well as the completion time and the tool tip path length at different time delays.


Subject(s)
Laparoscopy/methods , Robotics/methods , Telemedicine/methods , Adolescent , Adult , Florida , Humans , Time Factors , Washington , Young Adult
11.
Article in English | MEDLINE | ID: mdl-19163986

ABSTRACT

Within the area of telerobotic surgery no standardized means of surgically relevant performance evaluation has been established. The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) Fundamentals of Laparoscopic Surgery (FLS) program provides a set of standardized tasks that are considered the 'gold standard' in surgical skill assessment. We present a methodology for using one of the SAGES FLS tasks for surgical robotic performance evaluation. The TeleRobotic FLS methodology is extendable to two other FLS tasks. Time delay in teleoperation in general and telesurgery in particular is one of the fundamental effects that limits performance in telerobotic surgery. In this pilot study the effect of time delay on the Block Transfer task performance was investigated. The RAVEN Surgical Robot was used in a master/slave configuration in which time delays of 0, 250, 500, and 1000 ms were introduced by a network emulator between the master (Surgeon Site) and the slave (Patient Site). The study included three subjects, each of whom was presented with three of the four conditions. The results show that one subject had a lower error rate with increasing time delay, whereas the other subjects had a higher error rate with increased delay. The subject with the longest average completion time suffered the least performance decrease under time delay.


Subject(s)
Laparoscopy/methods , Robotics/methods , Surgery, Computer-Assisted/methods , Task Performance and Analysis , Telemedicine/methods , Humans , Pilot Projects , Time Factors
12.
Surg Innov ; 14(2): 122-6, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17558018

ABSTRACT

The Global Operative Assessment of Laparoscopic Skills (GOALS) is a valid assessment tool for objectively evaluating the technical performance of laparoscopic skills in surgery residents. We hypothesized that GOALS would reliably differentiate between an experienced (expert) and an inexperienced (novice) laparoscopic surgeon (construct validity) based on a blinded videotape review of a laparoscopic cholecystectomy procedure. Ten board-certified surgeons actively engaged in the practice and teaching of laparoscopy reviewed and evaluated the videotaped operative performance of one novice and one expert laparoscopic surgeon using GOALS. Each reviewer recorded a score for both the expert and the novice videotape reviews in each of the 5 domains in GOALS (depth perception, bimanual dexterity, efficiency, tissue handling, and overall competence). The scores for the expert and the novice were compared and statistically analyzed using single-factor analysis of variance (ANOVA). The expert scored significantly higher than the novice did in the domains of depth perception (p = .005), bimanual dexterity (p = .001), efficiency (p = .001), and overall competence ( p = .001). Interrater reliability for the reviewers of the novice tape was Cronbach alpha = .93 and the expert tape was Cronbach alpha = .87. There was no difference between the two for tissue handling. The Global Operative Assessment of Laparoscopic Skills is a valid, objective assessment tool for evaluating technical surgical performance when used to blindly evaluate an intraoperative videotape recording of a laparoscopic procedure.


Subject(s)
Cholecystectomy, Laparoscopic , Clinical Competence , Videotape Recording , Cholecystectomy, Laparoscopic/education , General Surgery/education , Humans , Intraoperative Period , Task Performance and Analysis
13.
IEEE Trans Biomed Eng ; 53(7): 1440-5, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16830951

ABSTRACT

With a focus on design methodology for developing a compact and lightweight minimally invasive surgery (MIS) robot manipulator, the goal of this study is progress toward a next-generation surgical robot system that will help surgeons deliver healthcare more effectively. Based on an extensive database of in-vivo surgical measurements, the workspace requirements were clearly defined. The pivot point constraint in MIS makes the spherical manipulator a natural candidate. An experimental evaluation process helped to more clearly understand the application and limitations of the spherical mechanism as an MIS robot manipulator. The best configuration consists of two serial manipulators in order to avoid collision problems. A complete kinematic analysis and optimization incorporating the requirements for MIS was performed to find the optimal link lengths of the manipulator. The results show that for the serial spherical 2-link manipulator used to guide the surgical tool, the optimal link lengths (angles) are (60 degrees, 50 degrees). A prototype 6-DOF surgical robot has been developed and will be the subject of further study.


Subject(s)
Computer-Aided Design , Minimally Invasive Surgical Procedures/instrumentation , Robotics/instrumentation , Surgery, Computer-Assisted/instrumentation , Telemedicine/instrumentation , Equipment Design , Equipment Failure Analysis , Minimally Invasive Surgical Procedures/methods , Quality Control , Robotics/methods , Rotation , Surgery, Computer-Assisted/methods , Telemedicine/methods
14.
J Heart Lung Transplant ; 25(5): 539-43, 2006 May.
Article in English | MEDLINE | ID: mdl-16678032

ABSTRACT

BACKGROUND: The optimal management of cholelithiasis after heart transplant remains unclear. We use expectant management based on symptoms, without screening studies or prophylactic treatment. We hypothesized that expectant management for cholelithiasis after heart transplant does not result in significant mortality or morbidity from gallstone-associated disease. METHODS: Between November 1985 and August 2004, 409 heart transplants were performed in 402 recipients at the University of Washington. This is a non-concurrent cohort study of these recipients. RESULTS: Among recipients, 24 underwent cholecystectomy before heart transplant. After transplant, in the remaining 378 patients, 34 were found to have gallstones during the observation period. There was no mortality from gallstone-associated disease. Thirty patients developed morbidity from gallstones, including 25 cases of biliary colic, 3 of acute cholecystitis and 2 of pancreatitis, and there was 1 abnormal liver function test. Acute cholecystitis and pancreatitis were treated with conservative management followed by cholecystectomy. Cholecystectomy was performed in 32 patients after transplant. Indications included symptomatic cholelithiasis in 31, and prophylactic cholecystectomy prior to kidney transplant in 1. The laparoscopic approach was performed in 25 of these 32 patients. There was no mortality from cholecystectomy, but there were 4 complications: surgical site infections (n = 2); wound dehiscence (n = 1); and bile duct injury (n = 1). Median hospital stay was 1 day. CONCLUSIONS: Our expectant management for cholelithiasis after heart transplant resulted in no mortality or significant morbidity related to delay in treatment. Symptomatic cholelithiasis was successfully treated with cholecystectomy, mostly with the laparoscopic approach. We believe expectant management is safe for patients after heart transplant.


Subject(s)
Cholelithiasis/therapy , Heart Transplantation , Postoperative Complications/therapy , Adult , Cholecystectomy , Cholelithiasis/complications , Cholelithiasis/surgery , Female , Humans , Male , Middle Aged
15.
IEEE Trans Biomed Eng ; 53(3): 399-413, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16532766

ABSTRACT

Minimally invasive surgery (MIS) involves a multidimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in defining objective criteria for characterizing surgical performance. The Blue DRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools synchronized with the endoscopic view of the surgical scene. Modeling the process of MIS using a finite state model [Markov model (MM)] reveals the internal structure of the surgical task and is utilized as one of the key steps in objectively assessing surgical performance. The experimental protocol includes tying an intracorporeal knot in a MIS setup performed on an animal model (pig) by 30 surgeons at different levels of training including expert surgeons. An objective learning curve was defined based on measuring quantitative statistical distance (similarity) between MM of experts and MM of residents at different levels of training. The objective learning curve was similar to that of the subjective performance analysis. The MM proved to be a powerful and compact mathematical model for decomposing a complex task such as laparoscopic suturing. Systems like surgical robots or virtual reality simulators in which the kinematics and the dynamics of the surgical tool are inherently measured may benefit from incorporation of the proposed methodology.


Subject(s)
Endoscopy/methods , Expert Systems , Minimally Invasive Surgical Procedures/methods , Models, Biological , Robotics/methods , Surgery, Computer-Assisted/methods , Task Performance and Analysis , Computer Simulation , Endoscopes , Humans , Man-Machine Systems , Markov Chains , Minimally Invasive Surgical Procedures/instrumentation , Models, Statistical , Robotics/instrumentation , Stochastic Processes , Surgery, Computer-Assisted/instrumentation , User-Computer Interface
16.
Stud Health Technol Inform ; 119: 349-54, 2006.
Article in English | MEDLINE | ID: mdl-16404076

ABSTRACT

Several criteria exist for determining the optimal design for a surgical robot. This paper considers kinematic performance metrics, which reward good kinematic performance, and dynamic performance metrics, which penalize poor dynamic performance. Kinematic and dynamic metrics are considered independently, and then combined to produce hybrid metrics. For each metric, the optimal design is the one that maximizes the performance metric over a specific design space. In the case of a 2-DOF spherical mechanism for a surgical robot, the optimal design determined by kinematic metrics is a robot arm with link angles (alpha(12)=90 degrees , alpha(23)=90 degrees ). The large link angles are the most dextrous, but have the greatest risk of robot-robot or robot-patient collisions and require the largest actuators. The link lengths determined by the dynamic metrics are much shorter, which reduces the risk of collisions, but tend to place the robot in singularities much more frequently. When the hybrid metrics are used, and a restriction that the arm must be able to reach a human's entire abdomen, the optimal design is around (alpha(12)=51 degrees, alpha(23)=54 degrees). The hybrid design provides a compromise between dexterity and compactness.


Subject(s)
Equipment Design , Minimally Invasive Surgical Procedures , Robotics , United States
17.
Article in English | MEDLINE | ID: mdl-15544237

ABSTRACT

Mechanical testing of abdominal organs has a profound impact on surgical simulation and surgical robotics development. Due to the nonlinear and viscoelastic nature of soft tissue it is crucial to test them in surgically relevant ranges of applied force, deformation, and duration for incorporating haptic realism into surgical simulators and for safe operation of surgical robots. In order to determine these ranges, a system known as the Blue DRAGON was used to track the motions and the forces applied to surgical tools during live procedures for quantifying how surgeons typically perform a minimally invasive surgical procedure. Thirty-one surgeons of varying skill were recorded performing three different surgical tasks. Grasping force (as applied to the tool handles) and handle angle for each tool were the signals of interest among 26 channels total acquired by the system in real time. These data were analyzed for their magnitudes and frequency content. Using the tool contact state, an algorithm selected tissue grasps to analyze measures during grasps only, as well as obtain grasp durations. The mean force applied to the tool handles during tissue grasps was 8.52 N +/- 2.77 N; maximum force was 68.17 N. Ninety-five percent of the handle angle frequency content was below 1.98 Hz +/- 0.98 Hz. Average grasp time was 2.29 s +/- 1.65 s, and 95% of all grasps were held for 8.86 s +/- 7.06 s or less. The average maximum grasp time during these tasks was 13.37 s +/- 11.42 s. These results form the basis for determining how abdominal tissues are to be mechanically tested in ranges and durations of force and deformation that are surgically realistic. Additionally, this information may serve as design specifications for new surgical robots or haptic simulators.


Subject(s)
Hand Strength , Laparoscopy , Surgical Instruments , Animals , Biomechanical Phenomena , Humans , Models, Animal , Robotics , Swine , Task Performance and Analysis , United States
18.
Stud Health Technol Inform ; 98: 174-9, 2004.
Article in English | MEDLINE | ID: mdl-15544266

ABSTRACT

Surgical robotic systems and virtual reality simulators have introduced an unprecedented precision of measurement for both tool-tissue and tool-surgeon interaction; thus holding promise for more objective analyses of surgical skill. Integrative or averaged metrics such as path length, time-to-task, success/failure percentages, etc., have often been employed towards this end but these fail to address the processes associated with a surgical task as a dynamic phenomena. Stochastic tools such as Markov modeling using a 'white-box' approach have proven amenable to this type of analysis. While such an approach reveals the internal structure of the of the surgical task as a process, it requires a task decomposition based on expert knowledge, which may result in a relatively large/complex model. In this work, a 'black box' approach is developed with generalized cross-procedural applications., the model is characterized by a compact topology, abstract state definitions, and optimized codebook size. Data sets of isolated tasks were extracted from the Blue DRAGON database consisting of 30 surgical subjects stratified into six training levels. Vector quantization (VQ) was employed on the entire database, thus synthesizing a lexicon of discrete, task-independent surgical tool/tissue interactions. VQ has successfully established a dictionary of 63 surgical code words and displayed non-temporal skill discrimination. VQ allows for a more cross-procedural analysis without relying on a thorough study of the procedure, links the results of the black-box approach to observable phenomena, and reduces the computational cost of the analysis by discretizing a complex, continuous data space.


Subject(s)
Clinical Competence , General Surgery/education , Guidelines as Topic , Manuals as Topic , Algorithms , Animals , Educational Measurement , Swine , United States
19.
Stud Health Technol Inform ; 94: 26-32, 2003.
Article in English | MEDLINE | ID: mdl-15455858

ABSTRACT

Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic feedback. Surgical simulation technology has progressed rapidly but lacks a comprehensive database of soft tissue mechanical properties with which to incorporate. Simulators are often designed purely based on what "feels right;" quantitative empirical data are lacking. A motorized endoscopic grasper was used to test abdominal porcine tissues in-vivo and in-situ with cyclic and static compressive loadings. An exponential constitutive equation was fit to the resulting stress-strain curves, and the coefficients were compared for various conditions. Stress relaxation for liver and small bowel were also examined. Differences between successive squeezes and between in-vivo and in-situ conditions were found.


Subject(s)
Abdomen , Computer Simulation , Connective Tissue/physiology , Surgical Instruments , Animals , Compressive Strength , In Vitro Techniques , Swine , User-Computer Interface
SELECTION OF CITATIONS
SEARCH DETAIL
...