Effects of phenylephrine and noradrenaline on coronary artery motion in an open-chest porcine beating heart model.

PURPOSE: During off-pump coronary artery bypass (OPCAB), surgeons are required to perform a precise anastomosis on the beating heart. The hypotension caused by vertical displacement of the heart during OPCAB is usually treated with vasopressors, such as noradrenaline and phenylephrine. However, the effects of these agents on coronary artery motion are unknown. The present study analyzed the motion of the target coronary arteries during noradrenaline or phenylephrine infusion using three-dimensional motion capture and reconstruction technology. METHODS: The left anterior descending (LAD) artery, left circumflex (LCX) artery and right coronary artery (RCA) of 12 female landrace pigs (weight 50 ± 1 kg) were stabilized using a tissue stabilizer. The motions in the regions were captured before and during noradrenaline (n = 5) and phenylephrine (n = 7) infusion. RESULTS: Noradrenaline (0.15 µg/kg/min) and phenylephrine (1.1 µg/kg/min) significantly increased the blood pressure. Noradrenaline significantly increased the motion parameters, such as the distance moved, maximum velocity, acceleration and deceleration at the LAD (4.2 vs. 7.9 mm, P = 0.025; 95.7 vs. 215.5 mm/s, P = 0.0074; 35.3 vs. 83.6 m/s(2), P = 0.0096 and -35.6 vs. -83.6 m/s(2), P = 0.005, respectively). The values during phenylephrine infusion did not change except for the distance moved at the LAD (3.8 vs. 7.7 mm, P = 0.042). The motion parameters at the LCX and RCA during noradrenaline and phenylephrine infusion did not change significantly. CONCLUSIONS: The effect of phenylephrine on the coronary artery motion was less dramatic than that of noradrenaline.

Softness sensor system for simultaneously measuring the mechanical properties of superficial skin layer and whole skin.

BACKGROUND/AIMS: Few attempts have been made to distinguish the softness of different skin layers, though specific measurement of the superficial layer would be useful for evaluating the emollient effect of cosmetics and for diagnosis of skin diseases. MATERIALS AND METHODS: We developed a sensor probe consisting of a piezoelectric tactile sensor and a load cell. To evaluate it, we firstly measured silicone rubber samples with different softness. Then, it was applied to human forearm skin before and after tape-stripping. A VapoMeter and skin-surface hygrometer were used to confirm removal of the stratum corneum. A Cutometer was used to obtain conventional softness data for comparison. RESULTS AND CONCLUSIONS: Both the piezoelectric tactile sensor and the load cell could measure the softness of silicone rubber samples, but the piezoelectric tactile sensor was more sensitive than the load cell when the reaction force of the measured sample was under 100 mN in response to a 2-mm indentation. For human skin in vivo, transepidermal water loss and skin conductance were significantly changed after tape-stripping, confirming removal of the stratum corneum. The piezoelectric tactile sensor detected a significant change after tape-stripping, whereas the load cell did not. Thus, the piezoelectric tactile sensor can detect changes of mechanical properties at the skin surface. The load cell data were in agreement with Cutometer measurements, which showed no change in representative skin elasticity parameters after tape-stripping. These results indicate that our sensor can simultaneously measure the mechanical properties of the superficial skin layer and whole skin.

Observation of local elastic distribution in aortic tissues under static strain condition by use of a scanning haptic microscope.

The purpose of this study was to observe variation in the local elastic distribution in aortic tissue walls under different static strain conditions, including physiological strain, by use of a scanning haptic microscope (SHM). Strain was applied by stretching aortic tissues in the circumferential direction by the simple tensile method or by the rod-insertion method to mimic in vivo internal pressure loading. SHM measurements in a saline solution at room temperature were performed on canine thoracic aorta using a glass needle probe with a diameter of ca 5 µm and a scanning area and point pitch of 160 × 80 µm and 2 µm, respectively. Under strain of 0-0.23, corresponding to internal pressure of 0-150 mmHg, wavy-shaped elastin fibers stretched until they were almost straightened, and the average elastic modulus increased almost linearly. Although there was little difference between the images obtained for the two different stretching methods, under high strain (>0.36; 250 mmHg) significant circumferential orientation of the collagen fibrils occurred with an increase in the average elastic modulus. It was concluded that the pressure resistance of the aorta under physiological strain was mainly afforded by elastin fibers; collagen fibrils contributed little except under much higher pressures.

Biomechanical properties and associated collagen composition in vaginal tissue of women with pelvic organ prolapse.

PURPOSE: The pelvic tissue of women with pelvic organ prolapse is stiffer than that of controls but there are scant data on the collagen composition that corresponds to these mechanical properties. We evaluated human vaginal wall stiffness using the novel scanning haptic microscope and correlated these measurements to collagen expression in women with and without pelvic organ prolapse. In this simultaneous biomechanical and biochemical assessment we evaluated the usefulness of this measurement technology for pelvic floor disorder research and confirmed an association between mechanical properties and composition. MATERIALS AND METHODS: The elastic constant (a measure of stiffness) of vaginal wall tissue was measured with the scanning haptic microscope. Protein expression of collagen types I and III of the same tissues were determined by Western blot. The Student t test was used for comparisons between groups. RESULTS: The anterior and posterior vaginal walls of premenopausal and postmenopausal women with pelvic organ prolapse were significantly stiffer than those of controls (p <0.05). Collagen III protein expression in the anterior vaginal wall in the control group was higher than in menopausal women. Collagen I expression was not significantly different between controls and cases. CONCLUSIONS: The scanning haptic microscope produced reliable mechanical measurements in small tissue samples without tissue destruction. Vaginal wall tissues are stiffer in women with pelvic organ prolapse than in controls. This vaginal wall stiffness was associated with lower protein expression of collagen III in the vaginal wall compared to that in asymptomatic controls.

Landiolol reduces coronary artery motion in an open-chest porcine model: implications for off-pump coronary artery bypass surgery.

Reduction of target coronary artery motion is imperative for successful off-pump coronary artery bypass surgery. We hypothesized that landiolol, a novel ultra-short-acting selective ß-1 blocker, would reduce such coronary artery motion. To test this hypothesis, the motion of the left anterior descending artery of the porcine heart (n = 8) was analyzed by three-dimensional digital motion capture and reconstruction technology with or without continuous landiolol infusion. Landiolol (0.12 mg/kg/min) significantly decreased the heart rate (105 ± 16 vs. 90 ± 9 beats/min), three-dimensional distance moved (-20.4% vs. control), maximum velocity (-30.0% vs. control), acceleration (-31.1% vs. control), and deceleration (-28.6% vs. control) without inducing a significant change in the systolic blood pressure (85 ± 18 vs. 81 ± 22 mmHg), cardiac output (4.3 ± 1.4 vs. 4.1 ± 1.3 l/min), or pulmonary wedge pressure (7.8 ± 3.0 vs. 8.7 ± 2.9 mmHg). Landiolol reduces the heart rate and coronary artery motion with stable hemodynamics, which may facilitate performing precise anastomosis on the beating heart.

Variations in local elastic modulus along the length of the aorta as observed by use of a scanning haptic microscope (SHM).

Variations in microscopic elastic structures along the entire length of canine aorta were evaluated by use of a scanning haptic microscope (SHM). The total aorta from the aortic arch to the abdominal aorta was divided into 6 approximately equal segments. After embedding the aorta in agar, it was cut into horizontal circumferential segments to obtain disk-like agar portions containing ring-like samples of aorta with flat surfaces (thickness, approximately 1 mm). The elastic modulus and topography of the samples under no-load conditions were simultaneously measured along the entire thickness of the wall by SHM by using a probe with a diameter of 5 µm and a spatial resolution of 2 µm at a rate of 0.3 s/point. The elastic modulus of the wall was the highest on the side of the luminal surface and decreased gradually toward the adventitial side. This tendency was similar to that of the change in the elastin fiber content. During the evaluation of the mid-portion of each tunica media segment, the highest elastic modulus (40.8 ± 3.5 kPa) was identified at the thoracic section of the aorta that had the highest density of elastic fibers. Under no-load conditions, portions of the aorta with high elastin density have a high elastic modulus.

Simulation of vaginal wall biomechanical properties from pelvic floor closure forces map.

We simulated the way that pelvic floor muscles (PFM) generate zonal compression on the vagina and urethra in order to maintain urinary continence. Raw data were obtained using a probe to map the distribution of vaginal closure forces. Simulation model was made using ordinary Spring-mass model. The biomechanical properties are applied to the spring of the model. We simulated four models that are applied to asymptomatic subjects as controls and patients based on information obtained from the measured force maps using a vaginal probe. PFM values are measured when subjects are relaxed and during voluntary PFM contraction. Results show that simulation clearly distinguished between controls and patents and demonstrates that in the controls, after a period of 0.075 sec from the time when the rest force was added, the model was deformed to a neutral shape, and after another period of 0.075 sec from the time when the contract force was added at intervals of 0.001 sec, the closure force reaches maximum. The results render the simulation of the vaginal wall deformations that was obtained directly by the force maps. It shows that in controls the wall model is significantly deformed compared to that from the patient's model. In this research we simulated the response of the vaginal walls using spring mass model and the force maps of vaginal closure forces applied to control subjects and patients. The process of deformation of the vaginal wall is thus visualized demonstrating the relative pathologic differences between the two groups.

Surface elasticity imaging of vascular tissues in a liquid environment by a scanning haptic microscope.

The objective of this study was to make an elasticity distribution image of natural arteries in a liquid environment at high resolution at the micrometer level and at a wide area at the sub-square millimeter level by improving the scanning haptic microscope (SHM), developed previously for characterization of the stiffness of natural tissues. The circumferential sections (thickness, 1.0 mm) of small-caliber porcine arteries (approximately 3-mm diameter) were used as a sample. Measurement was performed by soaking a probe (diameter, 5 microm; spatial resolution, less than 2 microm) in saline solution at an appropriate depth. The vascular tissues were segregated by multi-layering a high elasticity region with mainly elastin (50.8 +/- 13.8 kPa) and a low one with mainly collagen and smooth muscle cells (17.0 +/- 9.0 kPa), as observed previously in high humidity conditions. The elasticity was measured repeatedly with little change for over 4 h in a liquid environment, which enabled observation with maintenance of high precision of a large area of at least 1,200 x 100 microm, whereas the elasticity was increased with time by the dehydration of samples with shrinkage in the air, in which an averaged elasticity in the overall area was approximately doubled within 2 h. This simple, inexpensive system allows observation of the distribution of the surface elasticity at the extracellular matrix level of vascular tissues in a liquid environment close to the natural one.

Local elasticity imaging of vascular tissues using a tactile mapping system.

This study aimed to map the elasticity of a natural artery at the micron level by using a tactile mapping system (TMS) that was recently developed for characterization of the stiffness of tissue slices. The sample used was a circumferential section (thickness, approximately 1 mm) of a small-caliber porcine artery (diameter, approximately 3 mm). Elasticity was measured with a probe of diameter 1 microm and a spatial resolution of 2 microm at a rate of 0.3 s per point, without significant sample invasion. Topographical measurements were also performed simultaneously. Wavy regions of high elasticity, layered in the circumferential direction, were measured at the tunica media, which was identified as an elastin-rich region. The Young's modulus of the elastin-rich region in the media was 50.8 +/- 13.8 kPa, and that of the elastin-rich region of the lamina elastica interna was 69.0 +/- 12.8 kPa. Both these values were higher than the Young's modulus of the other regions in the media, including smooth muscle cells and collagen fibrils (17.0 +/- 9.0 kPa). TMS is simple and inexpensive to perform and allows observation of the distribution of the surface elastic modulus at the extracellular matrix level in vascular tissue. TMS is expected to be a powerful tool in evaluation of the maturation and degree of reconstruction in the development of tissue-engineered or artificial tissues and organs.

Influence of pelvic floor muscle contraction on the profile of vaginal closure pressure in continent and stress urinary incontinent women.

PURPOSE: We characterized the vaginal pressure profile as a representation of closure forces along the length and circumference of the vaginal wall. Vaginal pressure profile data were used to test the hypothesis that the strength of pelvic floor muscle contractions differs significantly between continent women and women with stress urinary incontinence. MATERIALS AND METHODS: Vaginal pressure profile recordings were made in 23 continent subjects and in 10 patients with stress urinary incontinence. The recordings characterized closure forces along the entire length of the vagina and identified differences among the anterior, posterior, left and right sides of the vaginal wall. Using a novel, directionally sensitive vaginal probe we made vaginal pressure profile measurements with the women at rest and during pelvic floor muscle contraction while supine. RESULTS: The nature of the vaginal pressure profile was characterized in terms of force distribution in the anterior and posterior vaginal walls, which was significantly greater than that on the left and right sides. The continent group had significant greater maximum pressure than the stress urinary incontinence group on the posterior side at rest (mean +/- SE 3.4 +/- 0.3 vs 2.01 +/- 0.36 N/cm(2)) and during pelvic floor muscle contraction (4.18 +/- 0.26 vs 2.25 +/- 0.41 N/cm(2)). The activity pressure difference between the posterior and anterior vaginal walls in the continent group was significantly increased when the pelvic floor muscles contracted vs that at rest (3.29 +/- 0.21 vs 2.45 +/- 0.26 N/cm(2)). However, the change observed in the stress urinary incontinence group was not significant (1.85 +/- 0.38 vs 1.35 +/- 0.27 N/cm(2)). CONCLUSIONS: The results demonstrate that the voluntary pelvic floor muscles impose significant closure forces along the vaginal wall of continent women but not in women with stress urinary incontinence. The implication of these findings is that extrinsic urethral closure pressure is insufficiently augmented by pelvic floor muscle contraction in women with stress urinary incontinence.

Assessment of deformation of the mitral valve complex during off-pump coronary artery bypass surgery using three-dimensional echocardiography in a porcine model.

BACKGROUND: This study aimed to assess the deformation of the mitral valve complex during the displacement of the beating heart by using three-dimensional echocardiography in a porcine off-pump coronary artery bypass grafting (OPCAB) model. METHODS: In nine healthy swine, we positioned the beating heart as an OPCAB model, i.e. control, left anterior descending artery (LAD), right coronary artery (RCA), and left circumflex artery (LCX) positions. In each position, three-dimensional echocardiography was performed to assess the mitral valve complex with hemodynamic parameters. We analyzed the deformation of the mitral valve and the three-dimensional coordinates of the papillary muscles. RESULTS: There was a significant increase in maximum tenting length and tenting volume (control 0.70±0.30, LAD 0.65±0.27, RCA 0.79±0.23, LCX 0.95±0.34cm3, p<0.05) in the LCX position compared with the other positions. The posterior papillary muscle (PPM) angle had a significant relationship with the tenting volume (r=-0.643, p<0.001). The PPM was displaced to the medial side in the LAD and LCX positions (p<0.01). CONCLUSIONS: The prime cause of the deformation of the mitral leaflets is suggested to be the displacement of the PPM associated with the change in geometry of the left ventricle in a porcine model.

Evaluation of the dynamic responses of female pelvic floor using a novel vaginal probe.

The female pelvic floor (PF) provides anatomical support to many visceral organs, such as uterus, bladder, urethra, vagina, and rectum. Physiologically, the PF is made up of a number of highly coordinated muscle groups organized to respond to postural and abdominal stresses to maintain continence. In this article, we describe a new methodology for the evaluation of PF strength using a novel vaginal probe design, having force and displacement sensors. This design was derived on the basis of imaging data showing that force/displacement characteristics are important determinants of the integrity of the PF function. The prototype probe used was constructed to evaluate the dynamic responses to slow voluntary contractions as well as reflex stress contractions. Initial clinical experiments were performed on nine healthy female subjects. The probe recorded the force and displacement signals on the anterior and posterior sides of the subjects' middle vaginal wall in voluntary PF muscle contraction and cough. The time domain and frequency domain characteristics of the dynamic responses, including the force and displacement responses, of the vaginal wall were measured and the power and energy associated with the dynamic responses of the PF were analyzed showing the differences between the dynamic characteristics of the voluntary PF muscle contraction and cough. Results show that voluntary PF muscle contractions have higher amplitudes, longer duration, and higher power than reflex contractions. The design of this probe enables the measurement of force and displacement during rapidly occurring events.

Spatial distribution of vaginal closure pressures of continent and stress urinary incontinent women.

Clinically the strength of the contraction of the female pelvic floor is qualitatively evaluated by vaginal tactile palpation. We therefore developed a probe to enable the quantitative evaluation of the closure pressures along the vagina. Four force sensors mounted on the four orthogonal directions of an intra-vaginal probe were used to measure the vaginal pressure profile (VPP) along the vaginal wall. Clinical experiments on 23 controls and 10 patients with stress urinary incontinence (SUI) were performed using the probe to test the hypothesis that the strength of pelvic floor muscle (PFM) contractions, imposed by voluntary contraction, is related to urinary continence. The results show that VPPs, characterized in terms of pressure distribution on the anterior and posterior vaginal walls, are significantly greater than those in the left and right vaginal walls. When the PFM contracted, the positions of the maximum posterior pressures in continent females and SUI patients were 0.63+/-0.15 cm and 1.19+/-0.2 cm proximal from their peak points of anterior pressure, which are 1.52+/-0.09 cm and 1.69+/-0.13 cm proximal from the introitus of vagina, respectively. The statistical analysis shows that the maximum posterior vaginal pressures of the controls were significantly greater than those of the SUI patients both at rest (continent: 3.4+/-0.3 N cm(-2), SUI: 2.01+/-0.36 N cm(-2), p<0.05) and during PFM contraction (continent: 4.18+/-0.26 N cm(-2), SUI: 2.25+/-0.41 N cm(-2), p<0.01). In addition, the difference between the posterior and anterior vaginal walls is significantly increased when the controls contract the PFM. By contrast, there are no significant differences in the SUI group. The results show that the VPP measured by the prototype probe can be used to quantitatively evaluate the strength of the PFM, which is a clinical index for the diagnosis or assessment of female SUI.

The stiffness of normal and abnormal mitral valves.

BACKGROUND: Although it is well known that valvular lesions show changes in stiffness, this fact has not been studied objectively or quantitatively. METHODS: Using a tactile sensor, stiffness of the mitral valve was measured at 11 autopsies and 19 surgically excised specimens. The relationships between stiffness and histological state were investigated in 394 points of resected specimens. RESULTS: In normal mitral valves, the anterior leaflet was significantly stiffer than the posterior leaflet in all zones. The rough zone had the least stiffness in both leaflets. Mitral stenotic valves were significantly stiffer than normal in all zones, the rough zone had the greatest stiffness. The grade of fibrosis (r=0.862), hyalinosis (r=0.783), and calcification (r=0.464) had positive correlation with the stiffness, respectively. An S score that was composed of these three factors had strong positive correlation (r=0.935). The regression equation was: stiffness=2.882+2.304xS score (r(2)=0.88). With cut-off values of 8 g/cm for severe fibrosis, 10 for focal hyalinosis, 13 for diffuse hyalinosis, 15 for mild calcification and 18 for massive calcification, these changes were accurately (>90%) detected. The grade of myxoid change had mild negative correlation with the stiffness (r=-0.507). CONCLUSION: The actual value of stiffness of normal and abnormal mitral valves and the relationships between stiffness and histological changes were obtained. A tactile sensor promptly and accurately shows stiffness of the heart valve indicating its histological state. It can be a useful device for cardiovascular surgery.

Mouse zona pellucida dynamically changes its elasticity during oocyte maturation, fertilization and early embryo development.

A change in the elasticity of mouse zona pellucida was quantitatively evaluated during oocyte maturation, fertilization and early embryo development. Young's modulus of zona pellucida of germinal vesicle (GV), metaphase-II (MII), pronuclear (PN), 2cell, 4cell, 8cell, morulae (M) and early blastocyst (EB) stages was measured using a micro tactile sensor (MTS) and a chamber exclusively designed for the measurement. The MTS has very high sensitivity and a deformation of only 5 microm was sufficient to calculate the Young's modulus and the oocyte/embryo maintained its original spherical shape during the measurement. The Young's modulus of GV, MII, PN, 2cell, 4cell, 8cell, M and EB was 22.8+/-10.4 kPa (n=30), 8.26+/-5.22 kPa (n=74), 22.3+/-10.5 kPa (n=66), 13.8+/-3.54 kPa (n=41), 12.6+/-3.34 kPa (n=19), 5.97+/-4.97 kPa (n=6), 1.88+/-1.34 kPa (n=8) and 3.39+/-1.86 kPa (n=4), respectively. Experimental results clearly demonstrated that the mouse zona pellucida hardened following fertilization. Interestingly, once the zona pellucida hardened at the PN stage, it gradually softened as the embryo developed (i.e. it was found that the zona hardening is a transient phenomenon). Furthermore, the zona pellucida of the GV oocyte was as hard as that of the PN embryo and became soft as it matured to the MII stage. In addition, the safety of the MTS measurement for oocytes and embryos was discussed both theoretically and experimentally.

Considerations in the design and sensitivity optimization of the micro tactile sensor.

Although miniaturization has been considered the only technology with which to increase sensitivity of tactile sensors, we recently developed the micro tactile sensor (MTS) that performs with high sensitivity without microfabrication. In this study, we examined design and sensitivity optimization of the MTS using theory based upon Mason's equivalent circuit. The touch probe, which is attached to the lead zirconate titanate (PZT) element, was expressed as a purely inductive circuit component. Resonance frequency was calculated as a function of the length of the touch probe, and sensitivity was predicted to be dependent on the length. Furthermore, many kinds of MTS were fabricated with different touch probe lengths, and actual sensitivity was measured as phase shift between nonloaded and loaded conditions. And, from the consideration of theory and experimental data, a sensitivity coefficient was proposed and found to be useful.

Remote sensing of mechanical properties of materials using a novel ultrasound transducer and signal processing.

An ultrasound-based remote sensing method to evaluate the mechanical properties of materials is presented. This method consists of a disk-shaped, piezoelectric transducer, operating at its resonance frequency, and a phase-shifted, feedback circuit. Mechanical parameters are derived by analyzing the signal contained in the phase-shifted values of the reflected signal. It is concluded that, using this novel transducer system and signal processing, remote mechanical measurements can be made. Such measurements obviate the need to apply the force-deformation approach and may be used to enable stiffness imaging.

Multi-sensory surgical support system incorporating, tactile, visual and auditory perception modalities.

The incorporation of novel broad band sensory modalities, integrating tactile technology, with visual and auditory signals into the evolution of the next generation of surgical robotic is likely to significantly enhance their utility and safety. In this paper considerations are made of a system, where tactile information together with visual and audio feedback are integrated into a multisensory surgical support platform. The tactile sensor system uses a piezoelectric transducer (PZT) system to evaluate the haptic properties of tissues. The spatial position of the sensor is tracked by a video camera, visualizing the location of the marker. Tactile information is additionally converted to an audio signal, to represent tissue properties in terms of a frequency/amplitude modulated signal. Representative data were obtained from biological tissues demonstrating that the technology developed has potential applications in virtual systems or robotic tele-medical care. In view of these technical developments, consideration is made as to whether visual audio and tactile modalities act as independent sources of information.

Micro-mechanical sensing platform for the characterization of the elastic properties of the ovum via uniaxial measurement.

Stiffness is an important parameter in determining the physical properties of living tissue. Recently, considerable biomedical attention has centered on the mechanical properties of living tissues at the single cell level. In the present paper, the Young's modulus of zona pellucida of bovine ovum was calculated using Micro Tactile Sensor (MTS) fabricated using piezoelectric (PZT) material. The sensor consists of a needle-shaped 20-microm transduction point made using a micro-electrode puller and mounted on a micro-manipulator platform. Measurements were made under microscopic control, using a suction pipette to support the ovum in the same horizontal axis as the MTS. Young's modulus of ovum was found to be 25.3+/-7.94 kPa (n=28). This value was indirectly determined based on calibration curves relating change in resonance frequency (Deltaf(0)) of the sensor with tip displacement for gelatin at concentrations of 4%, 6%, and 8%. The regression equation between the rate of change in resonance frequency (versus sensor tip displacement), Deltaf(0)/x and Young's modulus is Deltaf(0)/x (Hz/microm)=0.2992 x Young's modulus (kPa)-1.0363. It is concluded that a reason that the stiffness of ovum measured in the present study is approximately six times larger than previously reported, may be due to the absence of large deformation present in of existing methodologies.

Development of a novel surgical support instrument and virtual system incorporating new tactile sensor technology.

Surgical practice would be significantly enhanced with robotic systems incorporating tactile sensors. Current tactile sensor technology consists mainly of strain gauge elements having a limited bandwidth. A novel tactile sensor system, has been developed using a piezoelectric transducer(PZT), to simulate the properties of the human hand for use as a surgical support instrument and a palpation probe. Visualization of tactile information as an audio signal is provided, representing tissue properties in terms of an amplitude and frequency modulated signal. Representative data measured from pig brain, lung, pancreas, tongue and liver show that the changes in frequency corresponds to tissues stiffness and contact pressure. The technology developed in this new surgical support system has potential applications in virtual systems or robotic tele-medical care.