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PubMed2000

Dietary influences on bone mass and bone metabolism: further evidence of a positive link between fruit and vegetable consumption and bone health?

BACKGROUND: The role of nutritional influences on bone health remains largely undefined because most studies have focused attention on calcium intake. OBJECTIVE: We reported previously that intakes of nutrients found in abundance in fruit and vegetables are positively associated with bone health. We examined this finding further by considering axial and peripheral bone mass and markers of bone metabolism. DESIGN: This was a cross-sectional study of 62 healthy women aged 45-55 y. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at the lumbar spine and femoral neck and by peripheral quantitative computed tomography at the ultradistal radial total, trabecular, and cortical sites. Bone resorption was calculated by measuring urinary excretion of pyridinoline and deoxypyridinoline and bone formation by measuring serum osteocalcin. Nutrient intakes were assessed by using a validated food-frequency questionnaire; other lifestyle factors were assessed by additional questions. RESULTS: After present energy intake was controlled for, higher intakes of magnesium, potassium, and alcohol were associated with higher total bone mass by Pearson correlation (P < 0.05 to P < 0.005). Femoral neck BMD was higher in women who had consumed high amounts of fruit in their childhood than in women who had consumed medium or low amounts (P < 0.01). In a regression analysis with age, weight, height, menstrual status, and dietary intake entered into the model, magnesium intake accounted for 12.3% of the variation in pyridinoline excretion and 12% of the variation in deoxypyridinoline excretion. Alcohol and potassium intakes accounted for 18.1% of the variation in total forearm bone mass. CONCLUSION: The BMD results confirm our previous work (but at peripheral bone mass sites), and our findings associating bone resorption with dietary factors provide further evidence of a positive link between fruit and vegetable consumption and bone health.

Absorptiometry, Photon↗
PubMed1998

Implementation of Section 255 of the Telecommunications Act of 1996: access to telecommunications services, telecommunications equipment, and customer premises equipment by persons with disabilities--FCC. Notice of proposed rulemaking.

This Notice of Proposed Rulemaking (NPRM) is an important step in the Commission's effort to increase the accessibility of telecommunications services and equipment to Americans with disabilities. The NPRM proposes a framework for implementing section 255 of the Communications Act of 1934 (Act), which requires telecommunications equipment manufacturers and service providers to ensure that their equipment and services are accessible to persons with disabilities, to the extent it is readily achievable to do so. In addition, if accessibility is not readily achievable, section 255 requires manufacturers and service providers to ensure compatibility with existing peripheral devices or specialized customer premises equipment commonly used by individuals with disabilities to achieve access, to the extent it is readily achievable to do so. The NPRM first explores the Commission's legal authority to establish rules implementing section 255. The NPRM then seeks comment on the interpretation of specific statutory terms that are relevant to the proceeding. Finally, the NPRM seeks comment on proposals to implement and enforce the requirement that telecommunications equipment and services be made accessible to the extent readily achievable. The actions proposed in the NPRM are needed to ensure that people with disabilities are not left behind in the telecommunications revolution and consequently isolated from contemporary life.

Communication Devices for People with Disabilities↗
PubMed2002

Biological parameters on computed tomography guided fine needle aspiration biopsy from peripheral primary non-small cell lung cancer.

Computed tomography (CT) guided fine needle aspiration biopsy (CT-guided FNAB) represents the procedure of choice for diagnosing peripheral primary lung cancer before surgery. The aim of the present study was to assess the reliability of the immunocytochemical evaluation of biological parameters and DNA flow cytometry on cellular material obtained from non-small cell lung cancer (NSCLC) patients by CT-guided FNAB. Thirty consecutive CT-guided FNABs obtained from NSCLC patients were submitted both to the immunocytochemical evaluation of p53, Ki67, bcl-2 and to flow cytometric DNA analysis. p53, Ki67 and bcl-2 were assessable in 60% (18/30), 53% (16/30) and 48% (10/21) of the cases, respectively. Flow cytometric DNA analysis was performed in 19 out of the 30 cases and 74% (14/19) of the histograms were evaluable. Cytofluorimetric S-phase fraction (SPF), was obtained in 57% (8/14) of the cases. The results of the current study suggest that CT-guided FNAB from primary NSCLC patients may represent an effective practice for the evaluation of biologic parameters and could be useful as a preoperative procedure. The role of neoadjuvant chemotherapy in operable NSCLC is still under debate. We suppose that in the future the presurgical characterization of NSCLC could suggest the opportunity of a neoadjuvant systemic treatment aimed to improve the clinical outcome. Moreover, in locally advanced or metastatic NSCLC immunocytochemistry could help to predict the response to chemotherapy and/or radiotherapy, avoiding ineffective treatments and supporting the development of more rational therapies.

Biopsy, Needle↗
PubMed1998

Orbital tumor in acute myeloid leukemia associated with karyotype 46,XX,t(8;21)(q22;q22): a case report.

Orbital tumor formation in acute myeloid leukemia (AML) is rare as an initial symptom. Furthermore, orbital granulocytic sarcoma (myeloid sarcoma) in pediatric patients is uncommon. We describe a 5-year-old Japanese girl with a left orbital mass as an initial symptom of AML, the mass revealed by computed tomography. Peripheral blood and bone marrow pictures and a chromosomal analysis disclosing 46,XX,t(8;21)(q22;q22) showed AML (M2 according to the French-American-British classification). She was treated with antileukemic chemotherapy systemically. Three weeks after the initiation of chemotherapy, the orbital tumor regressed markedly. AML as an initial symptom of the orbital mass should be fully considered in a differential diagnosis, even in the absence of typical leukemic symptoms, and chromosomal analysis and immunophenotypical analysis may explain the pathogenesis of the extramedullary leukemic tumor.

Acute Disease↗
PubMed2006

A neural network approach to motor-sensory relations during postural disturbance.

This study explored whether artificial neural networks (ANN) can be used to quantify the motor-sensory relationship during postural disturbance. An ANN model was constructed with seven mechanical stimuli to the visual, vestibular and somatosensory systems (i.e., head angular and linear accelerations, eye-target distance, ankle joint rotation and velocity, as well as normal and shear ground contact forces under the feet) as inputs, and electromyographic activities of tibialis anterior and gastrocnemius muscles as outputs. These inputs and outputs were directly measured during a sudden toes-up-down rotation of the supporting base in two groups of elderly subjects: people with peripheral neuropathy (NP) who have severe loss of mechanoreception in the sole of their feet and people without NP. The products of ANN weights were used in a summary statistic called the Q-value to estimate the contribution of each mechanical stimulus to sensory systems in determining each leg muscle activity. It was found that: (1) the stimuli to the vestibular system and/or ankle proprioceptors have greater contributions to leg muscle activities, especially the TA muscle, in people with NP than people without NP; (2) the stimuli to somatosensory receptors have the greatest contribution, and the stimuli to the vestibular system have the least contribution to both muscle activities in both groups. These findings are supported by previous studies and have demonstrated the potential of the Q-value concept in the ANN model in studying the motor-sensory relationship in human postural control.

Aged↗
PubMed2002

Computational model of the fluid dynamics of a cannula inserted in a vessel: incidence of the presence of side holes in blood flow.

Vascular access methods, performed by the insertion of cannulae into vessels, may disturb the physiological flow of blood, giving rise to non-physiological pressure variations and shear stresses. To date, the hydrodynamic behaviour of the cannulae has been evaluated comparing their pressure loss-flow rate relationships, as obtained from in vitro experiments using a monodimensional approach; this methodology neither furnish information about the local fluid dynamics nor the established flow field in specific clinical work conditions. Since the shear stress is a critical factor in the design of artificial circulatory devices, more knowledge should be necessary about the local values assumed by the haemodynamic parameters during cannulation. An alternative way to investigate the fluid dynamic as accurately as possible is given by numeric studies. A 3D model of cannula concentrically placed in a rigid wall vessel is presented, with the finite element methodology used to numerically simulate the steady-state flow field in two different venous cannulation case studies, with two cannulae having a central hole and two or four side holes, respectively, with the same boundary conditions. Lower velocity and shear stress peak values have been computed for the model with four side holes upstream of the central hole, in the region of the cannula where the inlet flows meet and towards cannula's outlet, due to the increased flow symmetry and inlet area with respect to the model with two side holes. Starting from the investigation of different cannula designs, numerically assessing the local fluid dynamics, indications can be drawn to support both the design phase and the device optimal clinical use, in order to limit risks of biomechanical origin. Thus the presence of four side holes implied, as a consequence of the greater inlet area and of the increased symmetry, a less disturbed blood flow, together with reduced shear stress values. Furthermore, results show that the numerical simulations furnished useful informations on the interaction between vessel and cannula, e.g. on the fluid dynamics establishing in the free luminal space left, in the vessel, by the inserted cannula.

Blood Flow Velocity↗
PubMed2006

Segmentation of bone CT images and assessment of bone structure using measures of complexity.

A nondestructive and noninvasive method for numeric characterization (quantification) of the structural composition of human bone tissue has been developed and tested. In order to quantify and to compare the structural composition of bones from 2D computed tomography (CT) images acquired at different skeletal locations, a series of robust, versatile, and adjustable image segmentation and structure assessment algorithms were developed. The segmentation technique facilitates separation from cortical bone and standardizes the region of interest. The segmented images were symbol-encoded and different aspects of the bone structural composition were quantified using six different measures of complexity. These structural examinations were performed on CT images of bone specimens obtained at the distal radius, humeral mid-diaphysis, vertebral body, femoral head, femoral neck, proximal tibia, and calcaneus. In addition, the ability of the noninvasive and nondestructive measures of complexity to quantify trabecular bone structure was verified by comparing them to conventional static histomorphometry performed on human fourth lumbar vertebral bodies. Strong correlations were established between the measures of complexity and the histomorphometric parameters except for measures expressing trabecular thickness. Furthermore, the ability of the measures of complexity to predict vertebral bone strength was investigated by comparing the outcome of the complexity analysis of the CT images with the results of a biomechanical compression test of the third lumbar vertebral bodies from the same population as used for histomorphometry. A multiple regression analysis using the proposed measures including structure complexity index, structure disorder index, trabecular network index, index of a global ensemble, maximal L-block, and entropy of x-ray attenuation distribution revealed an excellent relationship (r=0.959, r2=0.92) between the measures of complexity and compressive bone strength. In conclusion, the image segmentation techniques and the assessment of bone architecture by measures of complexity have been successfully applied to analyze high-resolution peripheral quantitative computed tomography (pQCT) and CT images obtained from the distal radius, humeral mid-diaphysis, third and fourth lumbar vertebral bodies, proximal femur, proximal tibia, and calcaneus. The proposed approach is of broad interest as it can be applied for the quantification of structures and textures originating from different imaging modalities in other fields of science.

Aged↗
PubMedDate not supplied

Detection of inflammation in aortic aneurysms with indium 111-oxine--labeled leukocyte imaging.

BACKGROUND: The exact cause of aortic aneurysms is not completely understood. Histologically, the atherosclerotic lesions present in an aneurysm contain numerous inflammatory cells. This finding represents active atherosclerosis, which can cause lesion expansion. In this study we investigated the role of scintigraphy in the evaluation of inflammation in aortic aneurysms. METHODS AND RESULTS: We performed imaging using indium 111-oxine--labeled leukocytes in 14 patients with aortic aneurysms (10 thoracic and 4 abdominal) diagnosed by computed tomography. Peripheral blood evidence of inflammation was assessed on the same day. In 8 patients who subsequently underwent graft replacement of the aneurysm, the excised specimen was examined for evidence of inflammatory infiltration and correlated with the scintigraphic findings. Scintigraphic accumulation of labeled leukocytes was present in 10 of the 14 patients. Although all patients had a small increase in the erythrocyte sedimentation rate, there was no significant difference in the erythrocyte sedimentation rate between patients with positive and negative scintigram results. In 5 of the 8 surgical patients with positive scintigram results, the resected specimens demonstrated numerous inflammatory cells in the adventitia of the aortic wall and atherosclerotic changes in the media. There was no correlation between the presence of periaortic inflammatory adhesions at the time of surgery and the scintigraphic results. CONCLUSIONS: The accumulation of In-111-oxine--labeled leukocytes is a potentially useful scintigraphic marker of inflammatory infiltration in aortic aneurysms.

Aged↗
PubMed1995

Prospective assessment of an artificial neural network for the detection of peripheral vascular disease from lower limb pulse waveforms.

The diagnostic performance of an artificial neural network pulse classification system for the detection of peripheral vascular disease was investigated prospectively. Lower limb photoelectric plethysmographic pulses, and Doppler ankle/brachial pressure index (ABPI) measurements (pre- and post-exercise) were obtained from 200 patients referred to a vascular investigation laboratory. A single toe pulse was processed and used as input data to a neural network which had been trained previously with a set of pulses from 100 legs. The neural network outputs represented the diagnostic arterial disease classifications defined by the ABPI. From the 200 patients entered prospectively, 266 legs were available for neural network assessment. A network sensitivity of 92% and specificity of 63% were achieved with a diagnostic accuracy of 80%. By using a higher confidence for the classification decision a small, but insignificant overall improvement was obtained. When a borderline classification was introduced 100% sensitivity and 100% negative predictive value were obtained, though 31% of legs were unclassifiable. Nevertheless, the very high sensitivity and negative predictive value could make this quick and simple technique the one of choice for the first stage in screening large numbers of subjects.

Adult↗
PubMed1991

Recognition of synthetic speech by hearing-impaired elderly listeners.

The Modified Rhyme Test (MRT), recorded using natural speech and two forms of synthetic speech, DECtalk and Votrax, was used to measure both open-set and closed-set speech-recognition performance. Performance of hearing-impaired elderly listeners was compared to two groups of young normal-hearing adults, one listening in quiet, and the other listening in a background of spectrally shaped noise designed to simulate the peripheral hearing loss of the elderly. Votrax synthetic speech yielded significant decrements in speech recognition compared to either natural or DECtalk synthetic speech for all three subject groups. There were no differences in performance between natural speech and DECtalk speech for the elderly hearing-impaired listeners or the young listeners with simulated hearing loss. The normal-hearing young adults listening in quiet out-performed both of the other groups, but there were no differences in performance between the young listeners with simulated hearing loss and the elderly hearing-impaired listeners. When the closed-set identification of synthetic speech was compared to its open-set recognition, the hearing-impaired elderly gained as much from the reduction in stimulus/response uncertainty as the two younger groups. Finally, among the elderly hearing-impaired listeners, speech-recognition performance was correlated negatively with hearing sensitivity, but scores were correlated positively among the different talker conditions. Those listeners with the greatest hearing loss had the most difficulty understanding speech and those having the most trouble understanding natural speech also had the greatest difficulty with synthetic speech.

Adult↗
PubMed2002

Learning intravenous cannulation: a comparison of the conventional method and the CathSim Intravenous Training System.

Intravenous cannulation is a nursing procedure carried out in some clinical units that may induce trauma and discomfort. Nurses should be well prepared before practising the procedure with clients. Conventionally, a plastic arm was used for practice but, with innovative developments in technology, a computer program called the CathSim Intravenous Training System (CathSim ITS) is available for this purpose. This study was conducted to compare the effectiveness of learning using a plastic arm with the CathSim ITS. Twenty-eight nurses were divided into two groups and randomly assigned to the two different methods: plastic arm (control group) or CathSim ITS (experimental group). Both groups were provided with 1 hour of theory input and 2 hours of nursing laboratory work. When the nurses felt ready to practise on clients, their performances were assessed by researchers with an intravenous cannulation qualification using a validated checklist. Prior to the assessment, trait and state anxiety levels were measured using the State-Trait Anxiety Inventory (Hong Kong Chinese adaptation) to check whether anxiety would affect the performance. Following the assessment, a semi-structured interview was conducted to reveal my knowledge acquired through using the selected method. Both the control and CathSim ITS groups demonstrated a high success rate, scoring 100% and 92.86%, respectively, with their first client. The semi-structured interviews revealed that the CathSim ITS group appreciated several features of their assigned method. However, there is room for further development.

Catheterization, Peripheral↗
PubMed1999

Effect of catheter placement on 3-D velocity profiles in curved tubes resembling the human coronary system.

Novel measurement techniques based on intravenous ultrasound (IVUS) technology ('IVUS-Flowmetry') require the location of a catheter inside the coronary bed. The present study quantifies disturbances in the 3-D velocity profile induced by catheter placement inside a tube, applying computational fluid dynamics. Two curved, circular meshes (radius K = 0.025 m and K = 0.035 m) with and without a catheter inside the lumen were applied. The catheter was located at the inner curve, the outer curve and at the top position. Boundary conditions were: no slip on the wall, zero stress at the outlet, uniform inflow with entrance velocities of 0.1, 0.2 and 0.4 m/s. Curvature-associated centrifugal forces shifted the maximal velocity to the outer curve and introduced two symmetrical vortices. Additional catheter placement redistributed the 3-D axial velocity field away from the catheter, which was accompanied by the appearance of multiple low-strength vortices. In addition, peak axial velocity increased, peak secondary velocities decreased, axial pressure drop increased and shear stress increased. Flow calculations simulated to resemble IVUS-based flowmetry changed by only 1% after considering secondary velocity. In conclusion, placement of a catheter inside a curved tube resembling the human coronary system changes the velocity field and reduces secondary patterns. The present study supports the usefulness of catheter-based flowmetry during resting flow conditions. During hyperemic flow conditions, flow measurements might be accompanied by large axial pressure drops because the catheter, itself, might act as a significant stenosis.

Blood Flow Velocity↗
PubMed2006

Simulation improves resident performance in catheter-based intervention: results of a randomized, controlled study.

OBJECTIVES: Surgical simulation has been shown to enhance the training of general surgery residents. Since catheter-based techniques have become an important part of the vascular surgeon's armamentarium, we explored whether simulation might impact the acquisition of catheter skills by surgical residents. METHODS: Twenty general surgery residents received didactic training in the techniques of catheter intervention. Residents were then randomized with 10 receiving additional training with the Procedicus, computer-based, haptic simulator. All 20 residents then participated in 2 consecutive mentored catheter-based interventions for lower extremity occlusive disease in an OR/angiography suite. Resident performance was graded by attending surgeons blinded to the resident's training status, using 18 procedural steps as well as a global rating scale. RESULTS: There were no differences between the 2 resident groups with regard to demographics or scores on a visuospatial test administered at study outset. Overall, residents exposed to simulation scored higher than controls during the first angio/OR intervention: procedural steps (simulation/control) (50 +/- 6 vs. 33 +/- 9, P = 0.0015); global rating scale (30 +/- 7 vs. 19 +/- 5, P = 0.0052). The advantage provided by simulator training persisted with the second intervention (53 +/- 6 vs. 36 +/- 7, P = 0.0006); global rating scale (33 +/- 6 vs. 21 +/- 6, P = 0.0015). Moreover, simulation training, particularly for the second intervention, led to enhancement in almost all of the individual measures of performance. CONCLUSION: Simulation is a valid tool for instructing surgical residents and fellows in basic endovascular techniques and should be incorporated into surgical training programs. Moreover, simulators may also benefit the large number of vascular surgeons who seek retraining in catheter-based intervention.

Angiography↗
PubMed1993

Development of a neural network screening aid for diagnosing lower limb peripheral vascular disease from photoelectric plethysmography pulse waveforms.

An artificial neural network (ANN) was trained to classify photoelectric plethysmographic (PPG) pulse waveforms for the diagnosis of lower limb peripheral vascular disease (PVD). PPG pulses from the lower limbs, and pre- and post-exercise Doppler ultrasound ankle to brachial systolic blood pressure ratio measurements were obtained from patients referred to a vascular investigation laboratory. A single PPG pulse from the big toe of each leg was processed and normalized, and used as input data to the ANN. The ANN outputs represented the diagnostic classifications (normal, significant PVD and major PVD) and the ANN was trained with the ankle to brachial pressure indices (ABPI). The ANN structure consisted of an input layer (50 neuron units from the PPG pulse input), a single hidden layer (15 neurons) and an output layer (3 neurons for the PVD diagnoses). The back-propagation learning algorithm was used to train the ANN for 500 epochs with a PPG training set of pulses from 100 legs. Test data for network assessment comprised pulses from a further 50 legs (20 normal and 30 PVD, of which 15 were categorized as having major disease). A network sensitivity of 93% and specificity of 85% was achieved with respect to the Doppler ABPI standard, giving a diagnostic accuracy of 90%. The results of this study indicate that a neural network can be trained to distinguish between PPG pulses from normal and diseased lower limb arteries. The simplicity of PPG measurement and neural network classification holds promise for the screening of lower limb arterial PVD.

Humans↗
PubMed2006

Effects of calcium supplementation on clinical fracture and bone structure: results of a 5-year, double-blind, placebo-controlled trial in elderly women.

BACKGROUND: Increased dietary calcium intake has been proposed as a population-based public health intervention to prevent osteoporotic fractures. We have examined whether calcium supplementation decreases clinical fracture risk in elderly women and its mechanism of action. METHODS: Five-year, double-blind, placebo-controlled study of 1460 women recruited from the population and older than 70 years (mean age, 75 years) who were randomized to receive calcium carbonate, 600 mg twice per day, or identical placebo. The primary end points included clinical incident osteoporotic fractures, vertebral deformity, and adverse events ascertained in 5 years. Bone structure was also measured using dual x-ray absorptiometry of the hip and whole body, quantitative ultrasonography of the heel, and peripheral quantitative computed tomography of the distal radius. RESULTS: Among our patients, 16.1% sustained 1 or more clinical osteoporotic fractures. In the intention-to-treat analysis, calcium supplementation did not significantly reduce fracture risk (hazard ratio, 0.87; 95% confidence interval, 0.67-1.12). However, 830 patients (56.8%) who took 80% or more of their tablets (calcium or placebo) per year had reduced fracture incidence in the calcium compared with the placebo groups (10.2% vs 15.4%; hazard ratio, 0.66; 95% confidence interval, 0.45-0.97). Calcium-treated patients had improved quantitative ultrasonography findings of the heel, femoral neck and whole-body dual x-ray absorptiometry data, and bone strength compared with placebo-treated patients. Of the 92 000 adverse events recorded, constipation was the only event increased by the treatment (calcium group, 13.4%; placebo group, 9.1%). CONCLUSION: Supplementation with calcium carbonate tablets supplying 1200 mg/d is ineffective as a public health intervention in preventing clinical fractures in the ambulatory elderly population owing to poor long-term compliance, but it is effective in those patients who are compliant.

Absorptiometry, Photon↗
PubMed2002

Surgical indications in idiopathic splenomegaly.

HYPOTHESIS: The incidence of primary lymphoma of the spleen in patients with idiopathic splenomegaly is significant. DESIGN: Retrospective review of all patients referred to a general surgical service for splenectomy. SETTING: A large tertiary care hospital. PATIENTS: Between 1994 and 2001, 86 nontrauma patients were referred for splenectomy. Of these, 18 had idiopathic splenomegaly despite prior workup with computed tomography, peripheral smear, bone marrow biopsy, and laboratory testing. All patients were symptomatic and displayed varying degrees of cytopenia. INTERVENTION: All 18 patients underwent open splenectomy for diagnosis and treatment of their cytopenias. MAIN OUTCOME MEASURE: Incidence of lymphoma in the pathologic specimens. RESULTS: The mean size of the spleens was 21 cm (range, 14-34 cm) and mean weight was 996 g (range, 320-1840 g). In all 18 patients, the surgical specimen provided a diagnosis. Sarcoidosis was discovered in 4 patients, and 1 patient had Castleman disease. Six patients with the benign diagnosis of hypersplenism received no further interventions, and the cytopenias resolved in all 6 cases. The 7 remaining patients (39%) were diagnosed with lymphoma. Five had marginal zone lymphoma, and 2 had a more aggressive B-cell lymphoma. Three patients required chemotherapy, but 4 are still in remission since their splenectomies and show no evidence of active disease. The mean follow-up was 20 months. CONCLUSIONS: A high percentage of patients with splenomegaly of unknown etiology will have primary lymphoma of the spleen. Splenectomy is both diagnostic and therapeutic and should be considered for all patients with idiopathic splenomegaly.

Adult↗
PubMed1999

Reliability of nerve conduction studies among active workers.

Nerve conduction studies play an important role in clinical practice and research. Given their widespread use, reliability of tests merits careful attention. We assessed interexaminer and intraexaminer reliability of median and ulnar sensory nerve measures of amplitude, onset latency, and peak latency. In a two-phase cross-sectional study, two examiners tested 158 workers. Reliability was assessed with intraclass correlations (ICC) and kappa statistics. Median nerve measures were more reliable (ICC range, 0.76 to 0.92) than ulnar measures (ICC range, 0.22 to 0.85). Ulnar-onset latencies had the worst reliability. The median-ulnar peak latency difference was a particularly stable measure (ICC range, 0.79 to 0.92). The median-ulnar peak latency difference had high interexaminer reliability (kappa range, 0.71 to 0.79) for normal tests defined by cut points of 0.8 ms and 0.5 ms. Intraexaminer reliability was higher with the 0.8-ms cut point (kappa = 0.90 and kappa = 0.85 for examiners 1 and 2, respectively). Rather than absolute cut points to describe normality, a more rational interpretation of results can be made with ordered categories or continuous measures.

Adult↗
PubMed1999

Bone healing and mineralization, implant corrosion, and trace metals after nickel-titanium shape memory metal intramedullary fixation.

Its shape memory effect, superelasticity, and good wear and damping properties make the NiTi shape memory alloy a material with fascinating potential for orthopedic surgery. It provides a possibility for making self-locking, self-expanding, and self-compressing implants. Problems, however, may arise because of its high nickel content. The purpose of this work was to determine the corrosion of NiTi in vivo and to evaluate the possible deleterious effects of NiTi on osteotomy healing, bone mineralization, and the remodeling response. Femoral osteotomies of 40 rats were fixed with either NiTi or stainless steel (StSt) intramedullary nails. The rats were killed at 2, 4, 8, 12, 26, and 60 weeks. Bone healing was examined with radiographs, peripheral quantitative computed tomography, (pQCT) and histologically. The corrosion of the retrieved implants was analyzed by electron microscopy (FESEM). Trace metals from several organs were determined by graphite furnace atomic absorption spectrometry (GF-AAS) or by inductively coupled plasma-atomic emission spectrometry (ICP-AES). There were more healed bone unions in the NiTi than in the StSt group at early (4 and 8 weeks) time points. Callus size was equal between the groups. The total and cortical bone mineral densities did not differ between the NiTi and StSt groups. Mineral density in both groups was lower in the osteotomy area than in the other areas along the nail. Density in the nail area was lower than in the proximal part of the operated femur or the contralateral femur. Bone contact to NiTi was close. A peri-implant lamellar bone sheet formed in the metaphyseal area after 8 weeks, indicating good tissue tolerance. The FESEM assessment showed surface corrosion changes to be more evident in the StSt implants. There were no statistically significant differences in nickel concentration between the NiTi and StSt groups in any of the organs. NiTi appears to be an appropriate material for further intramedullary use because it has good biocompatibility in bone tissue.

Animals↗