Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine
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Proc Inst Mech Eng H · Jul 2012
Magnetic resonance imaging-compatible tactile sensing device based on a piezoelectric array.
Minimally invasive surgery is a widely used medical technique, one of the drawbacks of which is the loss of direct sense of touch during the operation. Palpation is the use of fingertips to explore and make fast assessments of tissue morphology. Although technologies are developed to equip minimally invasive surgery tools with haptic feedback capabilities, the majority focus on tissue stiffness profiling and tool-tissue interaction force measurement. ⋯ The sensing unit is based on a piezoelectric sensor methodology, which conforms to the stringent mechanical and electrical design requirements imposed by the magnetic resonance environment The sensor mechanical design and the device integration to a 0.2 Tesla open magnetic resonance imaging scanner are described, together with the device's magnetic resonance compatibility testing. Its design limitations and potential future improvements are also discussed. A tactile sensing unit based on a piezoelectric sensor principle is proposed, which is designed for magnetic resonance imaging guided interventions.
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Proc Inst Mech Eng H · Jun 2012
Gas flow between coaxial tubes: impedance to gas flow in an endotracheal tube increases with a catheter within.
The insertion of a suction catheter or a bronchoscope down an endotracheal tube increases the resistance to gas flow down the tube. The extent to which this occurs depends on the relative diameters of the endotracheal tube and the coaxially introduced catheter. This study utilises a laboratory model to quantify this effect, using a steady flow down an annulus between two tubes whose long axes lie co-axially. ⋯ The results show that for equal d(o)/d(i), and equal values of x, deltaP/deltaPo are lower for higher values of Re than for lower; and that for lower values of Re there is a more rapid increase in deltaP/deltaPo as x increases, than for higher Re, especially at low values of d(o)/d(i). This result quantifiably confirms clinical experience; that care must be taken in introducing a catheter down a neonatal endotracheal tube. Deviation of these results from the theoretical calculation is less for the smaller Reynolds numbers and smaller values of d(o)/d(i), because under these conditions the flow is more likely to be laminar, with a greater degree of concentricity.
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Proc Inst Mech Eng H · May 2012
Accurate multi-robot targeting for keyhole neurosurgery based on external sensor monitoring.
Robotics has recently been introduced in surgery to improve intervention accuracy, to reduce invasiveness and to allow new surgical procedures. In this framework, the ROBOCAST system is an optically surveyed multi-robot chain aimed at enhancing the accuracy of surgical probe insertion during keyhole neurosurgery procedures. The system encompasses three robots, connected as a multiple kinematic chain (serial and parallel), totalling 13 degrees of freedom, and it is used to automatically align the probe onto a desired planned trajectory. ⋯ The iterative targeting was tested in an operating room environment using a skull phantom, and the targets were selected on magnetic resonance images. The proposed targeting procedure allows about 0.3 mm to be obtained as the residual median Euclidean distance between the planned and the desired targets, thus satisfying the surgical accuracy requirements (1 mm), due to the resolution of the diffused medical images. The performances proved to be independent of the robot optical sensor calibration accuracy.
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Proc Inst Mech Eng H · Apr 2012
Association of limited joint mobility and increased plantar hardness in diabetic foot ulceration in north Asian Indian: a preliminary study.
The aim of this article is to investigate the association of limited joint mobility and foot sole hardness in north Asian Indian type 2 diabetic patients. Limited joint mobility and hardness of the foot sole were measured for 39 subjects attending the AIIMS Endocrinology & Metabolism Clinic. The total subject divided into three groups: 13 control subjects (nondiabetic), 13 diabetic patients without neuropathy and 13 diabetic neuropathy patients. ⋯ Also linear regression analysis showed that duration of diabetes was significantly associated with the joint mobility parameters. In this study we conclude that joint mobility had reduced further if neuropathy and increased foot sole hardness coexisted owing to high plantar pressures. Hence, both limited joint mobility and increased foot sole hardness appears to be important determinants of foot sole ulceration in diabetic neuropathic subject.
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Proc Inst Mech Eng H · Nov 2011
Case ReportsSimultaneous repair of two large cranial defects using rapid prototyping and custom computer-designed titanium plates: a case report.
Custom titanium cranioplasty plates, manufactured by a variety of techniques, have been used to repair a range of cranial defects. The authors present a case where two relatively large, adjacent cranial defects were repaired by custom computer-designed titanium plates. The two plates were designed and fabricated simultaneously using a unique methodology. ⋯ The cranioplasty procedure to implant both titanium cranial plates was performed efficiently with no intra-operative complications. Intra-operatively, an excellent fit was achieved. The careful planning of the plates enhanced the relative ease with which the cranial defects were repaired with an excellent cosmetic outcome.