Motion tracking systems for assessment of surgical skill.
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Clinical Competence↗
Biomedical subjects
F Bello
Publications and source records attributed to F Bello.
Simulating tele-manipulator controlled tool-tissue interactions using a nonlinear FEM deformable model.
Enhanced visualization of an operating scene presented by a robotically assisted tele-manipulator system such as the da Vinci(TM) can be provided through the use of augmented reality facilities. Generating overlays from 3D models and the intra-operative video allows the surgeon to acquire greater information about the surgical scene. Tool-tissue interactions must be tracked to ensure the overlays are updated regularly and accurately. The work presented here describes how these interactions may be modelled by integrating a nonlinear finite element model with the 3D reconstruction and using the tool kinematic data as input to the deformation.
Connective Tissue↗
Genetic structure of the genera Psorophora (Diptera: Culicidae) in Columbian and North American populations using isoenzymes and ITS2 sequences.
Two, a priori, Psorophora columbiae and one, a priori, Ps. toltecum populations from Colombia were studied by means of eleven isoenzyme loci. The levels of genetic diversity, Hardy-Weinberg equilibrium, gene flow estimates, isolation by distance and genetic relationships among these three populations were studied and the results were as follows: 1. The gene diversity levels were high as well as very similar among the three populations indicating no differences between them. 2. Within each population and from a hierarchical standpoint several loci were not in Hardy-Weinberg equilibrium simultaneously by excess and defect of heterozygous. This could reflect that several natural selection forces are acting upon these mosquito populations. 3. The gene flow estimate for these populations showed the existence of this event between them. This agrees quite well with the fact that the three populations really belong to a single species. In addition, maximum parsimony analyses with 16 isoenzyme for several individuals from four Colombian and two United States Psorophora populations showed that effectively only one species was present in the Colombian area surveyed, and that this species is Ps. columbiae, which hardly contrast with that previously suggested by other authors.
Animals↗
Bimodal assessment of laparoscopic suturing skills: construct and concurrent validity.
BACKGROUND: The assessment of technical skills should provide objective feedback and judge suitability of progress during training. The aim of this study was to validate two objective assessment techniques for laparoscopic suturing and demonstrate a correlation between them. METHODS: Six experts, seven surgeons skilled in laparoscopic suturing, and 13 with no laparoscopic suturing skills were asked to place two or three intracorporeal sutures on a synthetic suture pad. The latter group was given video-based instructions prior to the execution of the sutures. Ergonomic conditions were standardized for all subjects. The procedures were recorded on videotape and two blinded observers rated the first suture of each subject on a 29-point checklist. A motion analysis system, Imperial College Surgical Assessment Device, was used to assess psychomotor skills. RESULTS: There was a significant difference in the time taken (p = 0.000) and total path length (p = 0.000) per suture across the groups. There were also a significant difference in the total checklist score (p = 0.000) and its individual categories. The was a strong correlation between the total path length and the total checklist score (coefficient, 0.78; p < 0.001). CONCLUSIONS: A combination of the motion analysis system and the checklist would make the process of formative feedback during the learning of intracorporeal suturing objective and comprehensive.
Clinical Competence↗
Dexterity enhancement with robotic surgery.
BACKGROUND: The aim of this study was to quantify the extent of dexterity enhancement in robotic surgery as compared to laparoscopic surgery. METHODS: Ten surgeons with varying laparoscopic suturing experience were asked to place three sutures on a suture pad. The sutures were placed laparoscopically, robotically with 2-D vision and robotically with 3-D vision. The da Vinci systems Application Programming Interface (API) was used for positional data. A validated motion analysis system was used for data retrieval for the laparoscopic task. Custom software was developed for data analysis. RESULTS: Compared to laparoscopic suturing, when the task was undertaken robotically with 2-D vision there was a 20% reduction in the time taken but this was not significant (p = 0.07). There was a 55% reduction in the path traveled by the right hand (p = 0.01) and a 45% reduction in the path traveled by the left hand (p = 0.008). When the task was undertaken robotically with 3-D vision, there was a 40% reduction in the time taken (p = 0.01). There was a 70% reduction in the path traveled by right hand (p = 0.008) and a 55% reduction by the left hand (p = 0.08). CONCLUSIONS: The presence of wristed instrumentation, tremor abolition, and motion scaling enhance dexterity by nearly 50% as compared to laparoscopic surgery. 3-D vision enhances dexterity by a further 10-15%. In addition, the presence of 3-D vision results in a 93% reduction in skills-based errors.
Clinical Competence↗
The benefits of stereoscopic vision in robotic-assisted performance on bench models.
BACKGROUND: Previous studies have failed to establish clear advantages for the use of stereoscopic visualization systems in minimal-access surgery. The aim of this study was to objectively assess whether stereoscopic visualization improves performance on bench models using the da Vinci robotic system. METHODS: Eleven surgeons carried out a series of four tasks. Positional data streamed from the da Vinci system was analyzed by means of a previously validated custom-designed software-package. An independent blinded observer scored errors. Statistical analysis included the Wilcoxon signed rank test. A p < 0.05 was deemed significant. RESULTS: We found significant improvements in all tasks and for all parameters (p < 0.05). In addition, a significantly lower number of errors was scored using the stereoscopic mode as compared to the standard two-dimensional image (p < 0.001). CONCLUSION: Robotic-assisted performance on bench models is more efficient and accurate using stereoscopic visualization.
Data Display↗
Qualitative and quantitative analysis of the learning curve of a simulated surgical task on the da Vinci system.
BACKGROUND: Robotic telemanipulation systems provide solutions to the problems of less dexterity and visual constraints of minimally invasive surgery (MIS). However, their influence over surgeons' dexterity and learning curve needs to be assessed. We present motion analysis as an objective method to measure performance and learning progress.METHODS. Thirteen surgeons completed five synthetic small bowel anastomoses using the da Vinci system. Objective Structured Assessment of Technical Skills (OSATS) allowed qualitative analysis. Quantitative analysis used API software of the system to retrieve real-time robotic signal data of time, path length, and number of movements. Wilcoxon signed ranks test was used for statistical analysis. A p value <0.05 was considered significant.RESULTS. OSATS global scores were 18.6 points for the first attempt and 26 for the fifth attempt ( p < 0.02, Cronbach's alpha = 0.894). Paired data of motion analysis for attempts 1 vs 5 showed significant change: time taken 3507 sec and 2287 sec ( p < 0.008), total number of movements 2411 and 1387 ( p = 0.01), total path length 21,630 cm and 13,941 cm ( p = 0.01).CONCLUSIONS. A rapid learning curve to a competent level using the da Vinci system is possible aided by the system's intuitive motion. Motion analysis is a useful tool to measure performance in the da Vinci system compared to OSATS and time alone.
Anastomosis, Surgical↗
Evaluation of the benefit of VR simulation in a multi-media web-based educational tool.
WebSET is an Internet based educational tool that can be used on any standard personal computer. It has been developed by a European collaboration and integrates high quality multimedia learning materials with VR simulation. The aim of this study was to evaluate the benefit of the VR simulation on the learning of procedure based psychomotor skills. Subjects were divided into three groups. The group that used the entire package including the VR simulation were superior to the group that used only the multimedia component in terms of the their procedural skills in the post-training assessment. Both groups performed better than the controls.
Computer-Assisted Instruction↗
Retrograde amnesia and the volume of critical brain structures.
There are many controversies concerning the structural basis of retrograde amnesia (RA). One view is that memories are held briefly within a medial temporal store ("hippocampal complex") before being "consolidated" or reorganised within temporal neocortex and/or networks more widely distributed within the cerebral cortex. An alternative view is that the medial temporal lobes are always involved in the storage and retrieval (reactivation) of autobiographical memories (multiple trace theory). The present study used quantitative magnetic resonance imaging (MRI) in 40 patients with focal pathology/volume loss in different sites, to examine the correlates of impairment on three different measures of RA. The findings supported the view that widespread neural networks are involved in the storage and retrieval of autobiographical and other remote memories. Brain volume measures in critical structures could account for 60% of variance on autobiographical memory measures (for incidents and facts) in diencephalic patients and for 60-68% of variance in patients with frontal lesions. Significant correlations with medial temporal lobe volume were found only in the diencephalic group, in whom they were thought to reflect thalamic changes, but not in patients with herpes encephalitis or hypoxia in whom the temporal lobes were particularly implicated. The latter finding fails to support one of the main predictions of multiple trace theory, as presently expounded.
Amnesia, Retrograde↗
Validation of a web-based training tool for lumbar puncture.
WebSET is an Internet based educational tool that can be used on any standard personal computer. It has been developed by a European collaboration and integrates high quality courseware, self-assessment exercises, video clips and VR simulation. This pilot study was carried out to validate the lumbar puncture (LP) module in training. Subjects who had never performed an LP participated in the study. The subjects were randomized into 2 groups: 1) underwent training and 2) control group. Both groups performed a pre-test and post-test LP on a synthetic mannequin. There was a significant improvement in the training group in terms of performance assessment as compared to the control group. This study showed that there was a significant improvement in the performance of the procedure and in procedural knowledge after training with WebSET.
Computer Simulation↗
Structural MRI volumetric analysis in patients with organic amnesia, 1: methods and comparative findings across diagnostic groups.
BACKGROUND: If they are to be replicable, MRI volume measurements require explicit definitions of structures and of criteria for delineating these structures on MRI. Previously published volumes in healthy subjects show considerable differences in measurements across different studies, including a fourfold variation in estimates of hippocampal volume. Previous neuroimaging reports in patients with Korsakoff syndrome have generally found widespread or non-specific change, whereas in patients with herpes encephalitis the extent of pathological involvement reported beyond the temporal lobes has varied. METHOD: In the present study, a clear set of anatomical criteria and detailed MRI segmentation procedures were applied to measure whole brain, frontal and temporal lobe, and anterolateral and medial temporal volumes, as well as thalamic areas in patients with organic amnesia (from Korsakoff's syndrome, herpes encephalitis, and focal frontal lesions) as well as healthy controls. RESULTS: Patients with Korsakoff's syndrome showed decreased thalamic measurements but no significant changes in the medial temporal lobes, whereas patients with herpes encephalitis showed severe medial temporal but not thalamic atrophy. In the patients with known frontal lobe lesions, quantitative analysis on MRI showed reduced frontal lobe volume but no significant temporal lobe or thalamic atrophy. CONCLUSION: Quantified MRI can be a useful technique with which to examine brain-cognitive relations, provided that detailed techniques are explicitly described. In particular, specific patterns of volume change can be found in vivo in patients with Korsakoff's syndrome and those with herpes encephalitis.
Adult↗
Structural MRI volumetric analysis in patients with organic amnesia, 2: correlations with anterograde memory and executive tests in 40 patients.
BACKGROUND: Cognitive-MRI correlations have often been studied in disorders in which there are multiple cognitive deficits and widespread cortical atrophy, such as Alzheimer's dementia. In such circumstances, the interpretation of any single cognitive-structural correlation is equivocal. Only by measuring differing cognitive functions and a wide range of brain structures in patients with a varying distribution of lesions or atrophy can specific brain-cognitive relations be determined in neurological disorder. METHOD: In the present study, a clear set of anatomical criteria and detailed MRI segmentation procedures were applied to measure whole brain, and left and right frontal, temporal lobe, anterolateral and medial temporal volumes, as well as thalamic cross sectional areas in 40 patients with organic amnesia (from various diseases) and 10 healthy controls. RESULTS: Within the total patient group, anterograde memory measures correlated significantly with medial temporal, hippocampal, and thalamic measurements. A spatial memory measure correlated significantly with hippocampal volume, and temporal context memory with frontal volume. After a factor analysis of the cognitive measures, the association between anterograde memory and hippocampal volume was corroborated. Forgetting rates and subjective memory evaluations did not show any significant MR correlations and, of executive tests employed, only card sorting categories correlated significantly with frontal volume. CONCLUSION: Loss of volume in key brain structures (for example, hippocampus, thalamus) is detectable on quantitative MRI, and this loss of volume correlates significantly with impaired performance on measures of anterograde memory function. Correlations with hippocampal volume did not indicate a specific role in either recall or verbal memory, as opposed to recognition or visual memory.
Alcohol Amnestic Disorder↗
In vitro interaction between psychotropic drugs and alcohol dehydrogenase activity.
A series of CNS-stimulating and -depressant drugs have been studied for their in vitro interaction with horse liver alcohol dehydrogenase (ADH) activity. The depressant drugs studied included barbital, phenobarbital, thiopental, nitrazepam, chlorpromazine, sulpiride, clomethiazole, Li2CO3, diazepam, phenytoin, ethosuximide, morphine, and codeine. The stimulant drugs were theophylline, caffeine, amphetamine, imipramine, chlorimipramine, amitriptyline, and tranylcypromine. The results were as follows. First, ADH activity was inhibited by the action of chlorpromazine, tranylcypromine, imipramine, chlorimipramine, amitriptyline, sulpiride, amphetamine, codeine, ethosuximide, morphine, clomethiazole, nitrazepam, Li2CO3, theophylline, and phenobarbital, in descending order of inhibitory effect. Second, inhibition followed by activation of ADH activity was observed for imipramine and chlorimipramine. Third, activation of ADH activity was observed for phenytoin. Finally, the following drugs were not seen to exert any effect on ADH activity: barbital, thiopental, diazepam, and caffeine.
Alcohol Dehydrogenase↗
The use of continuous subcutaneous octreotide infusion in brittle type 1 diabetic patients.
Two Type 1 diabetic patients with brittle diabetes were successfully treated using continuous SC octreotide (Sandostatin) infusion (200 micrograms 24-h-1) for 6 months and 12 months. When the analogue was discontinued, rapid deterioration in glucose control and ketonuria recurred in one patient and diabetic ketoacidosis in the other. These were corrected after reinstitution of the analogue.
Adult↗
[Acute arsenic poisoning as contamination of commercial calcium carbide].
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Adolescent↗
[Treatment of diabetic ketoacidosis and hyperosmolar coma with low-dose insulin. Experience in a provincial hospital].
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Adolescent↗
[Contribution to the study of acquired megacolon].
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Humans↗
A geometry-and intensity-based partial volume correction for MRI volumetric studies.
Segmentation of objects of interest in magnetic resonance imaging is a necessary procedure for volumetric calculations. However, these direct measurements tend to be inaccurate due to the intrinsic MRI partial volume effects. In this paper, a general method for correcting these effects based on the geometry and grey level intensity of the segmented objects is presented. This method is independent of the segmentation strategy used to extract the objects of interest. An evaluation for three different segmentation methods is presented and it is shown that the proposed partial volume correction can improve the volume estimation of all three methods.
Brain↗