Biomedical subjects

Pablo Lamata

Publications and source records attributed to Pablo Lamata.

4 recordsLinked to original sources

PubMed2006

Virtual reality thread simulation for laparoscopic suturing training.

The level of realism in virtual reality trainers might not be proportional to its didactic value. As an example, three exercises to train suturing skills are proposed in this article. They use a discrete thread model with a simple but good enough behaviour, and constitute a training means for three laparoscopic skills: (1) Accurate grasping, which trains grasping a precise point in the thread. (2) Coordinated Pulling, which trains tightening the thread co-ordinately and in different space orientations; and (3) Knotting, which allow the surgeon to practice this manoeuvre. These three exercises, found interesting among experts in surgical training, are now being validated in MIS workshops at the Minimally Invasive Surgery Centre of Cáceres (Spain).

Humans↗

PubMed2006

Study of laparoscopic forces perception for defining simulation fidelity.

One of the most controversial dilemmas in virtual reality laparoscopic simulators design is the incorporation of force feedback (FF). This issue is approached with an experimental design in which surgeons assess the resistance against pulling of four different tissues, which are characterized with the acquisition of interaction forces. Comparing subjective assessments with objective force parameters we aim to determine the fidelity boundary beyond which no more realism is necessary in simulation. Interaction pulling forces of four tissues have been characterized, which can constitute a basis for requirements of a FF algorithm. Results have also led to the hypothesis that surgeons are able to differentiate tissues and perceive somesthesic information although resulting interaction forces are of the same magnitude than interferences like trocar friction.

Animals↗

PubMed2003

A registration-based approach to quantify flow-mediated dilation (FMD) of the brachial artery in ultrasound image sequences.

Flow-mediated dilation (FMD) offers a mechanism to characterize endothelial function and, therefore, may play a role in the diagnosis of cardiovascular diseases. Computerized analysis techniques are very desirable to give accuracy and objectivity to the measurements. Virtually all methods proposed up to now to measure FMD rely on accurate edge detection of the arterial wall, and they are not always robust in the presence of poor image quality or image artifacts. A novel method for automatic dilation assessment based on a global image analysis strategy is presented. We model interframe arterial dilation as a superposition of a rigid motion and a scaling factor perpendicular to the artery. Rigid motion can be interpreted as a global compensation for patient and probe movements, an aspect that has not been sufficiently studied before. The scaling factor explains arterial dilation. The ultrasound sequence is analyzed in two phases using image registration to recover both transformation models. Temporal continuity in the registration parameters along the sequence is enforced with a Kalman filter since the dilation process is known to be a gradual physiological phenomenon. Comparing automated and gold standard measurements (average of manual measurements) we found a negligible bias (0.05%FMD) and a small standard deviation (SD) of the differences (1.05%FMD). These values are comparable with those obtained from manual measurements (bias = 0.23%FMD, SD(intra-obs) = 1.13%FMD, SD(inter-obs) 1.20%FMD). The proposed method offers also better reproducibility (CV = 0.40%) than the manual measurements (CV = 1.04%).

Adult↗

PubMedDate not supplied

Conceptual framework for laparoscopic VR simulators.

Availability of YR laparoscopic simulation for surgical training has increased significantly. Nevertheless, few studies have explored such simulators' requirements and the degree of fidelity necessary to provide effective educational tools. The authors aim to identify which didactic resources available in YR simulation technologies are most important for laparoscopic training.

Computer Graphics↗