Touching reality: Bridging the user-researcher divide in upper-limb prosthetics.

Realistically improving upper-limb prostheses is only possible if we listen to users' actual technological needs.

Use of colour duplex ultrasound as a first line surveillance tool following EVAR is associated with a reduction in cost without compromising accuracy.

INTRODUCTION: CT scanning remains the postoperative surveillance imaging modality of choice following EVAR. Concerns regarding cost, exposure to ionising radiation and intravenous contrast have led to a search for a less expensive, equally efficacious and safer method of monitoring EVAR patients after endograft deployment. This study evaluated the cost saving obtained if CDUS was employed as a first line surveillance tool following EVAR, as well as comparing the two entities in terms of efficacy. PATIENTS & METHODS: Postoperative surveillance CTs and CDUS scans in the 145 patients who have undergone EVAR from 1st June 2003 to 1st July 2010 were compared for the detection of endoleak and determination of residual sac size. RESULTS: Adopting a protocol where CDUS was employed as the first line surveillance tool following EVAR would result in a reduction in the number of postoperative CTs required in 2010 from 235 to 36. Based on 2010 costings, this would equate to an estimated reduction in expenditure from €117,500 to €34,915 a saving of €82,585. CDUS had a sensitivity of 100% and a specificity of 85% in the detection of endoleaks compared to CT. The positive predictive value was 28% and negative predictive value 100%. The Pearson Coefficient correlation of 0.96 indicates a large degree of correlation between CDUS and CT when measuring residual aneurysm size following EVAR. CONCLUSION: CDUS can replace CT as the first line surveillance tool following EVAR. This is associated with a significant reduction in the cost of surveillance without any loss of imaging accuracy.

Transfusion requirements and outcomes in patients undergoing abdominal aortic surgery using intra-operative cell salvage.

BACKGROUND: Intraoperative cell salvage (ICS) is the recovery, anticoagulation, filtration and reinfusion of blood lost during surgery. The aim of this study is to determine the safety and efficacy of ICS in emergency and elective abdominal aortic surgery. METHODS: This study reviews volumes of blood loss, blood salvaged with ICS, allogenic blood requirements, and clinical outcomes in patients undergoing abdominal aortic surgery using ICS. RESULTS: Seventy-nine patients undergoing abdominal aortic surgery are included. Supplemental allogenic blood was not required in 45/79 (57%) of all patients. Transfusion with allogenic blood was not necessary in 41/63 (66%) of elective abdominal aortic aneurysm repairs. ICS was associated with no major complications. CONCLUSION: ICS is a safe procedure and substantially reduces the need for blood transfusion in patients undergoing abdominal aortic surgery. It may substantially alleviate shortages of allogenic blood and should be part of the armamentarium of vascular units.

Association of polymorphonuclear leukocytes with sites of aortic catheter-induced injury in rabbits.

The kinetics of the association of polymorphonuclear leukocytes (PMNs) with arterial balloon catheter-induced injury have been examined. An average of 6 X 10(7) PMNs were isolated from 20 ml of blood and labelled with 111In-oxine for reinfusion into the donor rabbit. The cells remained viable as demonstrated by both in vitro and in vivo tests of cell function. The abdominal aorta of rabbits was denuded of endothelium and immediately, 24 h, or 5 weeks later, exposed to autologous radiolabelled PMNs for 1 h. The presence of PMNs at sites of denudation was demonstrated by detection of the radioactive label and was confirmed by light and electron microscopy after 24 h, but not at 5 weeks. Immediately following denudation radioactivity was 2.44 +/- 0.33 times control (P = 0.006); 2.52 +/- 0.18 at 24 h (P = 0.005); and 1.88 +/- 0.32 times control at 5 weeks (P = 0.045). The presence of PMNs, or their products, 5 weeks after denudation suggests a more complex role of PMNs and possibly a direct involvement in the long term changes resulting from arterial balloon catheter injury.

Norepinephrine-induced vasoconstriction is increased in intimal hyperplastic arteries of the dog.

Norepinephrine-induced arterial contraction in vitro is known to be increased after endothelial denudation and during the subsequent development of intimal hyperplasia. We now report the response to norepinephrine in intimal-thickened iliac vessels in conscious dogs. Seven dogs underwent balloon catheter deendothelialization of the right iliac artery. Three weeks later, ultrasonic transducers were implanted on both iliac arteries to record dynamic vessel dimension. A catheter was inserted into the terminal abdominal aorta for drug infusion and blood pressure monitoring. The dogs were studied unsedated 2 days after instrumentation. Norepinephrine was infused at doses that did not affect blood pressure (0.01 to 0.05 micrograms/kg/min). Control vessel diameter decreased from 5.2 mm +/- 0.3 to 5.1 mm +/- 0.3 (2.4% +/- 1.0% when standardized to baseline diameter) and intimal hyperplastic vessels from 6.2 mm +/- 0.4 to 5.7 mm +/- 0.4 (7.6% +/- 1.7%). The difference between control and intimal hyperplastic vessel vasoconstriction was significant at p less than 0.0025. The calculated reduction in total vessel cross-section area for control vessels was 4.5% +/- 1.9%. In intimal hyperplastic vessels total cross-sectional area was reduced by 14.5% +/- 3.3% by vasoconstriction and the luminal cross-sectional area was reduced by 17.9% +/- 0.7% by the intimal hyperplasia. These data suggest that luminal compromise due to intimal hyperplasia is compounded by increased sensitivity to norepinephrine. This effect, demonstrated in a large elastic artery shortly after endothelial denudation, may be of even greater significance in a smaller vessel with advanced intimal hyperplasia.

Increased vascular contraction and sensitivity to norepinephrine after endothelial denudation is inhibited by prazosin.

The vasomotor function of rabbit aorta was examined after deendothelialization with a Fogarty balloon catheter and during the subsequent development of intimal hyperplasia. Helical strips of injured lower abdominal aortic tissue showed an increase in norepinephrine-induced contraction when compared with control strips from normal upper abdominal aorta. This increase was 235% +/- 40% of control immediately after injury and 341% +/- 51% at 28 days after injury. Standardized dose-response curves demonstrated that the injured tissue was increasingly sensitive over time to norepinephrine and that this was more marked at physiologic levels of norepinephrine. Contraction was blocked by prazosin hydrochloride but not by yohimbine or propranolol. Furthermore, a single intramuscular dose of prazosin hydrochloride 2 hours before injury significantly (p = 0.001) reduced the maximal contraction and sensitivity. These results imply an increase in vasomotor reactivity after deendothelialization mediated through the alpha 1-adrenergic receptor. These functional changes are related to the pertinent morphologic observations.

Non-specific abdominal pain in pre-menopausal women.

Non-specific abdominal pain (NSAP) is a well-recognized clinical problem which places a significant burden on health resources. We studied 100 premenopausal women who were admitted consecutively through the Accident and Emergency Department of the Mater Misericordiae Hospital to assess final diagnosis, duration of hospital stay, extent of investigation, recurrence of symptoms and final diagnosis. The patients were placed in the following diagnostic categories: Gynaecological (30%), Renal (9%), Acute appendicitis (23%), Miscellaneous (9%) and Non-specific abdominal pain which accounted for 29% of the admissions. The mean duration of hospital stay for patients with NSAP was 67 days, one third underwent specialized investigations and one third underwent appendicectomies for normal appendices. On review, one year after admission, 66% of patients admitted with NSAP were asymptomatic.

Bilateral subclavian steal syndrome.

BACKGROUND: Bilateral atherosclerotic subclavian artery occlusion is rare. AIM: To describe the surgical treatment of a patient with symptomatic bilateral subclavian artery occlusion. METHODS: A midline sternotomy and bilateral aorto-subclavian bypass was performed in a male with upper limb, exercise-induced vertigo. RESULTS: Postoperatively symptomatic improvement paralleled an increase in brachial systolic arterial blood pressure readings. CONCLUSION: Bypass grafting is the more durable option for subclavian artery occlusion, as angioplasty with or without stenting is associated with a higher rate of late stenosis.

Comparison of colour duplex ultrasound with computed tomography to measure the maximum abdominal aortic aneurysmal diameter.

Introduction. Maximum diameter of an abdominal aortic aneurysm (AAA) is the main indication for surgery. This study compared colour duplex ultrasound (CDU) and computed tomography (CT) in assessing AAA diameter. Patients and Methods. Patients were included if they had both scans performed within 90 days. Pearson's correlation coefficient, paired t-test, and limits of agreement (LOA) were calculated for the whole group. Subgroup analysis of small (<5.0 cm), medium (5.0-6.5 cm), and large (>6.5 cm) aneurysms was performed. A P value of <0.05 was considered statistically significant. Results. 389 patients were included, giving 130 pairs of tests for comparison. Excellent correlation was in the whole group (r = 0.95) and in the subgroups (r = 0.94; 0.69; 0.96, resp.). Small LOA between the two imaging modalities was found in all subgroups. Conclusion. Small aneurysms can be accurately measured using CDU. CDU is preferable for small AAAs, but cannot supplant CT for planning aortic intervention.

The Task-Dependent Efficacy of Shared-Control Haptic Guidance Paradigms.

Shared-control haptic guidance is a common form of robot-mediated training used to teach novice subjects to perform dynamic tasks. Shared-control guidance is distinct from more traditional guidance controllers, such as virtual fixtures, in that it provides novices with real-time visual and haptic feedback from a real or virtual expert. Previous studies have shown varying levels of training efficacy using shared-control guidance paradigms; it is hypothesized that these mixed results are due to interactions between specific guidance implementations ("paradigms") and tasks. This work proposes a novel guidance paradigm taxonomy intended to help classify and compare the multitude of implementations in the literature, as well as a revised proxy rendering model to allow for the implementation of more complex guidance paradigms. The efficacies of four common paradigms are compared in a controlled study with 50 healthy subjects and two dynamic tasks. The results show that guidance paradigms must be matched to a task's dynamic characteristics to elicit effective training and low workload. Based on these results, we provide suggestions for the future development of improved haptic guidance paradigms.

Eversion endarterectomy for external iliac artery occlusive disease.

INTRODUCTION: The advent of effective endovascular techniques has revolutionized the treatment of iliac occlusive disease. Long-segment iliac occlusions remain technically difficult to treat, particularly in the presence of femoral disease. Iliac endarterectomy is an established procedure for the treatment of iliac occlusive disease, but it has been suggested that in the era of effective endovascular intervention, its role is limited. METHODS: A review of all patients who had eversion endarterectomy of the external iliac artery from a single institution between 2000 and 2008. RESULTS: Twenty-one patients (18 male) underwent eversion external iliac endarterectomy, 15 for external iliac and 6 for iliofemoral disease. Mean age was 64.7 years (range: 46-78 years) and the modal American Society of Anaesthesiologists (ASA) grade was 3. The indications were critical ischemia (n = 16) and disabling claudication (n = 5). Twelve had adjunctive procedures. The mean follow-up was 25.3 months (range: 1-59 months). There were no technical failures. Seventeen patients had significant improvement in symptoms and three had moderate improvement. The cumulative primary patency at 1 year was 81%. One patient had no improvement (because of infrainguinal occlusive disease), and subsequently required femoro-popliteal bypass. There was no systemic morbidity within 30 days. There was 1 in-hospital death from sudden cardiac arrest (47 days postoperatively). Six patients died during follow-up (from unrelated illness). CONCLUSION: Eversion external iliac endarterectomy is an effective means of treating iliofemoral occlusive disease with excellent short-term outcomes and a low complication rate in a cohort with high levels of comorbidity.

Robotic training and clinical assessment of forearm and wrist movements after incomplete spinal cord injury: a case study.

The effectiveness of a robotic training device was evaluated in a 24-year-old male, cervical level four, ASIA Impairment Scale D injury. Robotic training of both upper extremities was provided for three hr/day for ten consecutive sessions using the RiceWrist, an electrically-actuated forearm and wrist haptic exoskeleton device that has been designed for rehabilitation applications. Training involved wrist flexion/extension, radial/ulnar deviation and forearm supination/pronation. Therapy sessions were tailored, based on the patient's movement capabilities for the wrist and forearm, progressed gradually by increasing number of repetitions and resistance. Outcome measures included the ASIA upper-extremity motor score, grip and pinch strength, the Jebsen-Taylor Hand Function test and the Functional Independence Measure. After the training, improvements were observed in pinch strength, and functional tasks. The data from one subject provides valuable information on the feasibility and effectiveness of robotic-assisted training of forearm and hand functions after incomplete spinal cord injury.

Robotic training and kinematic analysis of arm and hand after incomplete spinal cord injury: a case study.

Regaining upper extremity function is the primary concern of persons with tetraplegia caused by spinal cord injury (SCI). Robotic rehabilitation has been inadequately tested and underutilized in rehabilitation of the upper extremity in the SCI population. Given the acceptance of robotic training in stroke rehabilitation and SCI gait training, coupled with recent evidence that the spinal cord, like the brain, demonstrates plasticity that can be catalyzed by repetitive movement training such as that available with robotic devices, it is probable that robotic upper-extremity training of persons with SCI could be clinically beneficial. The primary goal of this pilot study was to test the feasibility of using a novel robotic device for the upper extremity (RiceWrist) and to evaluate robotic rehabilitation using the RiceWrist in a tetraplegic person with incomplete SCI. A 24-year-old male with incomplete SCI participated in 10 sessions of robot-assisted therapy involving intensive upper limb training. The subject successfully completed all training sessions and showed improvements in movement smoothness, as well as in the hand function. Results from this study provide valuable information for further developments of robotic devices for upper limb rehabilitation in persons with SCI.

Passive and Active Discrimination of Natural Frequency of Virtual Dynamic Systems.

It has been shown that humans use combined feedforward and feedback control strategies when manipulating external dynamic systems, and when exciting virtual dynamic systems at resonance, that they can tune their control parameters in response to changing natural frequencies. We present a study to determine the discrimination thresholds for the natural frequency of such resonant dynamic systems. Weber fractions (WFs in %) are reported for the discrimination of 1, 2, 4, and 8 Hz natural frequencies. Participants were instructed either to passively perceive or actively excite the virtual system via a one degree-of-freedom haptic interface with visual and/or haptic feedback. The average WF for natural frequency ranged from 4% to 8.5% for 1,2, and 4 Hz reference natural frequencies, while the WF was approximately 20% for systems with a reference natural frequency of 8 Hz. Results indicate that sensory feedback modality has a significant effect on WF during passive perception, but no significant effect in the active perception case. The data also suggest that discrimination sensitivity is not significantly affected by excitation mode. Finally, results for systems with equivalent natural frequencies but different spring stiffness indicate that participants do not discriminate natural frequency based on the maximum force magnitude perceived.

Altered catecholamine receptor affinity in rabbit aortic intimal hyperplasia.

Intimal thickening is a universal response to endothelial denudation and is also thought to be a precursor of atherosclerosis. We have demonstrated selective supersensitivity in arterial intimal hyperplasia to norepinephrine and we now report a possible mechanism for this. Binding studies in rabbit aorta with the selective alpha 1-adrenergic radioligand 125I-HEAT demonstrated that there was no change in receptor density (20 +/- 4 fmole/10(6) cells) in intact vascular smooth muscle cells at either 5 or 14 days after denudation. However, competition studies showed a 2.6-fold increase in alpha 1-adrenergic receptor affinity for norepinephrine in intimal hyperplastic tissue (P less than 0.05). This increased affinity for norepinephrine was associated with a greater increase in 32P-labeled phosphatidylinositol (148% intimal thickening versus 76% control) and phosphatidic acid (151% intimal thickening versus 56% control) following norepinephrine stimulation of free floating rings of intimal hyperplastic aorta. These data suggest that the catecholamine supersensitivity in rabbit aortic intimal hyperplasia is receptor mediated and may be linked to the phosphatidylinositol cycle.