Biomedical subjects

Rajni Patel

Publications and source records attributed to Rajni Patel.

5 recordsLinked to original sources

PubMed2006

Needle insertion into soft tissue: a survey.

Needle insertion in soft tissue has attracted considerable attention in recent years due to its application in minimally invasive percutaneous procedures such as biopsies and brachytherapy. This paper presents a survey of the current state of research on needle insertion in soft tissue. It examines the topic from several aspects, e.g. modeling needle insertion forces, modeling tissue deformation and needle deflection during insertion, robot-assisted needle insertion, and the effect of different trajectories on tissue deformation. All studies show that the axial force of a needle during insertion in soft tissue is the summation of different forces distributed along the needle shaft such as stiffness force, frictional force and cutting force. Some studies have modeled these forces. The force data in some procedures is used for identifying tissue layers as the needle is inserted or for path planning. Needle deflection and tissue deformation are major problems for accurate needle insertion and attempts have been made to model them. Using current models several insertion techniques have been developed which are briefly reviewed in this paper.

Adipose Tissue↗

PubMed2006

Control of soft tissue deformation during robotic needle insertion.

Accurate needle insertion into soft, inhomogeneous tissue is of practical interest because of its importance in percutaneous therapies. In procedures that involve multiple needle insertions such as transrectal ultrasound-guided prostate brachytherapy, it is important to reduce tissue deformation before puncture and during needle insertion. In order to reduce this deformation, we have studied the effect of different trajectories for a 2-DOF (degrees of freedom) robot performing needle insertion in soft tissue. To obtain an optimum trajectory, we have compared tissue indentation and frictional forces for different trajectories. According to the results of our experiments, infinitesimal force per tissue displacement is a useful parameter for online trajectory update. In addition, the results show that axial rotation can reduce tissue indentation before puncture and frictional forces after puncture. Our proposed position/force controller is shown to provide considerable improvement in performance with regard to minimizing tissue deformation before puncture.

Animals↗

PubMed2006

A haptics based simulator for laparoscopic pyeloplasty.

We present a methodology for modeling the surgical procedures involved in robotics-assisted Pyeloplasty, which is a minimally invasive surgical procedure for correcting a kidney ureteropelvic junction obstruction. The simulator facilitates surgical training of laparoscopic pyeloplasty by providing both visual and haptic feedback to the trainee.

Canada↗

PubMed2005

Effects of latency on telesurgery: an experimental study.

The paper is concerned with determining the feasibility of performing telesurgery over long communication links. It describes an experimental testbed for telesurgery that is currently available in our laboratory. The tesbed is capable of supporting both wired and satellite connections as well as simulated network environments. The feasibility of performing telesurgery over a satellite link with approximately 600 ms delay is shown through a number of dry and wet lab experiments. Quantative results of these experiments are also discussed.

Computer Communication Networks↗

PubMedDate not supplied

Transradial primary angioplasty and stenting in Indian patients with acute myocardial infarction: acute results and 6-month follow-up.

BACKGROUND: Coronary angioplasty and stent implantation is effective as primary intervention in acute myocardial infarction. Because of fewer puncture site complications and improved patient comfort, transradial access has been increasingly used as an alternative to transfemoral access for percutaneous coronary interventions. METHODS AND RESULTS: We studied 103 patients (94 men, 9 women: mean age 52.5 +/- 11.96 years) with a diagnosis of acute myocardial infarction (<12 hours after onset), who underwent primary percutaneous coronary intervention. Transradial access was used in all patients with a normal Allen's test and transfemoral access was used additionally only if intra-aortic balloon counterpulsation was required. Follow-up duration was 6 months. Transradial access was successfully achieved in all patients. Radial artery cannulation took <2 min in more than 85% patients. During percutaneous coronary intervention, cannulation to balloon inflation times and total procedure times were 11.3 +/- 5.2 min and 19.9 +/- 10.8 min, respectively. Stents were implanted in 99 (96.1%) patients andplain balloon angioplastywas performed in 3.9%. The primary success rate was 98.1%, with no major bleeding complications. Total length of hospitalization averaged 2.4 +/- 0.8 days. In-hospital major adverse clinical events rate was 5.9%. Six-month clinical follow-up was achieved for 84 (86.6%) patients. Six (7.1%) patients died during follow-up. Follow-up coronary angiography was performed in 22 (26.2%) patients. After 6 months, 7 patients required revascularizationof the target lesion. The rate of survival without myocardial infarction, bypass surgery or repeat coronary angioplasty was 88.5% at 6 months. CONCLUSIONS: Transradial access may represent a safe and feasible technique for performing primary percutaneous coronary intervention with good acute results and without major bleeding complications.

Adult↗