Biomedical subjects

Jaydev P Desai

Publications and source records attributed to Jaydev P Desai.

4 recordsLinked to original sources

PubMed2005

Force feedback plays a significant role in minimally invasive surgery: results and analysis.

OBJECTIVE: To evaluate the role of force feedback with applications to minimally invasive surgery (MIS). Two research hypotheses were tested using our automated laparoscopic grasper. SUMMARY BACKGROUND DATA: Conventional laparoscopic tools do not have the ability of providing force feedback to a surgeon when in use with or without robotic surgical systems. Loss of haptic (force and tactile) feedback in MIS procedures is a disadvantage to surgeons since they are conventionally used to palpating tissues to diagnose tissues as normal or abnormal. Therefore, the need exists to incorporate force feedback into laparoscopic tools. METHODS: We have developed an automated laparoscopic grasper with force feedback capability to help surgeons differentiate tissue stiffness through a haptic interface device. We tested our system with 20 human subjects (10 surgeons and 10 nonsurgeons) using our grasper to evaluate the role of force feedback to characterize tissues and answer 2 research hypotheses. RESULTS: Our experiments confirmed 1 of our 2 research hypotheses, namely, providing both vision and force feedback leads to better tissue characterization than only vision feedback or only force feedback. CONCLUSIONS: We have validated 1 of our 2 research hypotheses regarding incorporating force feedback with vision feedback to characterize tissues of varying stiffness.

Biocompatible Materials↗

PubMed2004

Robotic surgery: a current perspective.

OBJECTIVE: To review the history, development, and current applications of robotics in surgery. BACKGROUND: Surgical robotics is a new technology that holds significant promise. Robotic surgery is often heralded as the new revolution, and it is one of the most talked about subjects in surgery today. Up to this point in time, however, the drive to develop and obtain robotic devices has been largely driven by the market. There is no doubt that they will become an important tool in the surgical armamentarium, but the extent of their use is still evolving. METHODS: A review of the literature was undertaken using Medline. Articles describing the history and development of surgical robots were identified as were articles reporting data on applications. RESULTS: Several centers are currently using surgical robots and publishing data. Most of these early studies report that robotic surgery is feasible. There is, however, a paucity of data regarding costs and benefits of robotics versus conventional techniques. CONCLUSIONS: Robotic surgery is still in its infancy and its niche has not yet been well defined. Its current practical uses are mostly confined to smaller surgical procedures.

Cardiac Surgical Procedures↗

PubMed2004

Study of soft tissue cutting forces and cutting speeds.

A versatile equipment to study the cutting of soft tissue with surgery scalpel was designed and constructed. Experiments were performed with pig liver (ex-vivo) to measure the blade-tissue interaction forces at cutting speeds ranging from 0.1 cm/sec-2.54 cm/sec. The experimentally measured force-displacement curves reveal that the liver cutting process was made up of a sequence of repeating local units with similar features. Each local unit was comprised of a linear deformation phase followed by a crack growth phase. A method was developed to quantify the deformation resistance of the tissue during each local deformation phase in cutting. This deformation resistance was presented in the form of a self-consistent local effective Young's modulus (LEYM), and was determined by post-processing force-displacement data with finite element models. Values for LEYM were determined from plane-stress finite element model and plane-strain finite element model. The plane-stress LEYM values were within a close bound of the plane-strain values. Results of the self-consistent LEYM at different cutting speeds show that the tissue's resistance to deformation decreased as the cutting speed increased.

Animals↗

PubMed2003

Measuring forces in liver cutting: new equipment and experimental results.

We are interested in modeling the liver cutting process as accurately as possible by determining the mechanical properties experimentally and developing a predictive model that is self-consistent with the experimentally determined properties. In this paper, we present the newly developed hardware and software to characterize the mechanical response of pig liver during (ex vivo) cutting. We describe the custom-made cutting apparatus, the data acquisition system, and the characteristics of the cutting force versus displacement plot. The force-displacement behavior appears to reveal that the cutting process consists of a sequence of intermittent localized crack extension in the tissue on the macroscopic scale. The macroscopic cutting force-displacement curve shows repeating self-similar units of localized linear loading followed by sudden unloading. The sudden unloading coincides with observed onset of localized crack growth. This experimental data were used to determine the self-consistent local effective Young's modulus for the specimens, to be used in finite element models. Results from finite element analyses models reveal that the magnitude of the self-consistent local effective Young's modulus determined by plane-stress and plane-strain varies within close bounds. Finally, we have also observed that the local effective Young's modulus determined by plane stress and plane strain analysis decreases with increasing cutting speed.

Animals↗