Search PubMed⌕ Search

Biomedical subjects

David Zurakowski

Publications and source records attributed to David Zurakowski.

At least 55 records · Page 3Linked to original sources
PubMed2006

Fetal sheep development on ultrasound and magnetic resonance imaging: a standard for the in utero assessment of models of congenital abnormalities.

OBJECTIVE: To establish normative data for the size, conspicuity, and imaging characteristics of normal developing fetal sheep organs on ultrasound (US) and magnetic resonance (MR) imaging. METHODS: US and MR images of ten normal pregnant sheep, at 40, 65, 90, 115, and 140 gestational days (term = 145 days), were scored for organ conspicuity and imaging characteristics. Imaging biometry was correlated with specimens. Gestational age-based growth parameters were modeled using regression. RESULTS: Imaging biometry showed excellent correlation with specimens. Kidney, bladder, stomach, lung, liver, and spine were seen well from 65 days to term by US. More organs were consistently visible from 90 days to term by MR than by US. Most organ imaging characteristics tended not to change throughout gestation. CONCLUSION: Normal fetal sheep biometry, organ conspicuity, and imaging characteristics are established for US and MR and have potential use for the in utero assessment of sheep models of congenital abnormalities.

Animals↗
PubMed2006

Doxepin by topical application and intrathecal route in rats.

The tricyclic antidepressant, doxepin, has been reported to be a potent local anesthetic in rat sciatic nerve blockade. We hypothesized that topical doxepin has significantly longer antinociception compared with control and intrathecally compared with bupivacaine. Solutions of 0.3 mL of doxepin at 50, 75, and 100 mM and control (only the vehicle solution) were applied as a patch to the shaved dorsal skin of rats. After a 2-h contact interval, the patch was removed, and the rats were tested by three sets of six pinpricks. Inhibition of withdrawal to pain and cutaneous trunci muscle reflex were graded. In the second investigation, 60 muL of doxepin at 10, 20, and 50 mM was injected through intrathecal catheters implanted in the lumbar region of rats, which were evaluated for motor function, proprioception, and nociception. Topical doxepin at concentrations of 75 mM and 100 mM was significantly more effective than control (P < 0.05). Complete recovery for the 100-mM concentration occurred at 60 h, although two of five rats demonstrated erythema and scarring. Intrathecally, 20 mM of doxepin was not significantly different for motor and proprioceptive function from 23 mM (0.75%) bupivacaine; however, neurotoxicity (defined as persistent neurological deficit) commenced at 50 mM.

Administration, Topical↗
PubMed2006

Dexmedetomidine for pediatric sedation for computed tomography imaging studies.

Dexmedetomidine is a sedative with limited experience in the pediatric population. This is the first study that prospectively evaluates the sedation profile of a dexmedetomidine pilot program for pediatric sedation for radiological imaging studies. In March 2005, our hospital sedation committee approved the replacement of IV pentobarbital with dexmedetomidine as the standard of care for CT imaging. Detailed Quality Assurance (QA) data sheets collect relevant information on each patient, which is then logged into a computerized sedation database. After IRB approval, all QA data was accessed. Sixty-two patients with a mean age of 2.8 years (SD = 1.8, range 0.5-9.7) received IV (IV) dexmedetomidine administered as a 2 mcg/kg loading dose over 10 minutes, followed by repeat boluses of 2 mcg/kg over 10 minutes until target of Ramsay Sedation Score 4 (RSS) achieved. Patients were then maintained on 1 mcg/kg/hr infusion until imaging is completed. Repeated-measures ANOVA indicated that compared to pre-sedation values, the heart rate and mean arterial blood pressure decreased an average of 15% during bolus, infusion and recovery (P < 0.01). No significant changes were observed in respiratory rate or end-tidal CO2. Mean recovery time was 32 +/- 18 minutes. Based on our pilot results, dexmedetomidine may provide a reliable and effective method of providing sedation.

Child↗
PubMed2006

Predicting fracture through benign skeletal lesions with quantitative computed tomography.

BACKGROUND: There are no proven radiographic guidelines for predicting fracture risk in children and young adults with a benign skeletal lesion. An in vivo diagnostic study was conducted to determine whether a reduction in the load-carrying capacity of a bone measured with quantitative computed tomography was more accurate than current radiographic guidelines for predicting pathologic fracture in patients with a benign skeletal lesion. METHODS: Eighteen patients who presented with a fracture through a benign skeletal lesion were compared with eighteen patients who had a benign skeletal lesion that had been thought to be at increased risk for fracture on the basis of currently used radiographic criteria but had not fractured over a two-year period. Structural analysis was performed to calculate the resistance of the affected bones to compressive, bending, and torsional loads with use of serial transaxial quantitative computed tomography data obtained along the length of the bone containing the lesion and from homologous cross sections through the contralateral, normal bone. At each cross section, the ratio of the structural rigidity of the affected bone divided by that of the normal, contralateral bone was determined. The cross section with the greatest reduction in compressive, bending, and torsional rigidity was identified as that most likely to fracture. RESULTS: The mean age (and standard deviation) of the thirty-six patients was 12.5 +/- 3.6 years. Twenty lesions were located in the femur; eleven, in the tibia; three, in the humerus; one, in the ulna; and one, in the pelvis. A combination of the minimum bending and torsional rigidities calculated from the tomographic data provided optimal performance in differentiating between the fracture and non-fracture groups (100% sensitivity and 94% specificity). In contrast, plain radiographic criteria demonstrated 28% to 83% sensitivity and 6% to 78% specificity. CONCLUSIONS: The combination of bending and torsional rigidity measured noninvasively with quantitative computed tomography was more accurate (97%) for predicting pathologic fracture through benign bone lesions in children than were standard radiographic criteria (42% to 61% accuracy). We believe that this method can provide accurate objective criteria for planning treatment of benign bone lesions and monitoring treatment response.

Adolescent↗
PubMed2006

Delayed gadolinium-enhanced magnetic resonance imaging of cartilage to predict early failure of Bernese periacetabular osteotomy for hip dysplasia.

BACKGROUND: Hip dysplasia leads to abnormal loading of articular cartilage, which results in osteoarthritis. Pelvic osteotomies such as the Bernese periacetabular osteotomy can improve the mechanics of the joint, but the results are variable and appear to depend on the amount of preexisting arthritis. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a technique designed to measure early arthritis, and it potentially could be used to select hips with too severe arthritis to benefit from a joint-preserving reconstructive procedure. The purpose of our study was to identify radiographic, clinical, and magnetic resonance imaging measurements that predict failure after pelvic osteotomy. METHODS: We performed a cohort study of forty-seven patients undergoing a Bernese periacetabular osteotomy for the treatment of hip dysplasia. Our goal was to identify preoperative radiographic factors, such as the grade of arthritis, joint congruency, and the dGEMRIC index, that are associated with a poor outcome after osteotomy. RESULTS: Hips in which the osteotomy did not fail had a significant decrease in pain compared with their status preoperatively (p < 0.0001). Hips in which the osteotomy did fail had had significantly more arthritis on preoperative radiographs (as demonstrated by the joint space width and the Tönnis grade [p = 0.01]), more subluxation (p = 0.02), and a lower dGEMRIC index (p < 0.001) than the hips in which the osteotomy did not fail. Multivariate analysis identified the dGEMRIC index as the most important predictor of failure of the osteotomy. CONCLUSIONS: Bernese periacetabular osteotomy for the treatment of hip dysplasia can decrease pain and improve function in symptomatic dysplastic hips. The dGEMRIC index, as an early measure of osteoarthritis, appears to be useful for identifying poor candidates for a pelvic osteotomy. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

Acetabulum↗
PubMed2006

The influence of three-dimensional computed tomography reconstructions on the characterization and treatment of distal radial fractures.

BACKGROUND: Computed tomography identifies important characteristics of distal radial fractures better than plain radiographs do. Our hypothesis was that three-dimensional computed tomography images would further increase the reliability and accuracy of radiographic characterization of distal radial fractures. METHODS: Four independent observers evaluated radiographic images of thirty intra-articular fractures of the distal part of the radius for the presence of a fracture line in the coronal plane, impacted central articular fragments, the presence of comminution (defined as more than three articular fragments), and the number of fracture fragments. A treatment was selected on the basis of the interpretation of the radiographic studies. Three rounds of evaluation were compared: (1) radiographs and two-dimensional computed tomography, (2) radiographs and three-dimensional computed tomography two weeks later, and (3) all three types of images two weeks after that. This cycle was then repeated to assess intraobserver reliability. RESULTS: Three-dimensional computed tomography improved the intraobserver agreement, but not the interobserver agreement, regarding the presence of coronal plane fracture lines and central articular fragment depression. Three-dimensional computed tomography improved both the intraobserver and the interobserver agreement regarding the presence of articular comminution. Interobserver agreement increased when three-dimensional computed tomography was used to determine the exact number of articular fracture fragments. The sensitivity and accuracy of identifying specific fracture characteristics (as compared with intraoperative findings) improved when three-dimensional imaging was used in conjunction with two-dimensional imaging as compared with two-dimensional imaging alone. The addition of three-dimensional computed tomography to two-dimensional computed tomography influenced treatment recommendations, resulting in a significantly greater number of decisions for an open approach (p < 0.05) and combined dorsal and volar exposure (p < 0.001). CONCLUSIONS: Three-dimensional computed tomography improves both the reliability and the accuracy of radiographic characterization of articular fractures of the distal part of the radius and influences treatment decisions. Future studies will be required to determine the impact of these decisions on patient outcome.

Adult↗
PubMed2006

Analysis of transfusion predictors in shoulder arthroplasty.

BACKGROUND: We are not aware of any previous study that has examined predictive factors for blood transfusion after shoulder arthroplasty. We analyzed the association between clinical factors and the need for postoperative blood transfusion and documented the use and waste of predonated blood in a group of patients managed with shoulder arthroplasty. METHODS: A retrospective study of 119 patients who underwent 124 shoulder arthroplasties (including eighty-seven primary uncomplicated total shoulder arthroplasties, twenty-seven revision or complicated primary total shoulder arthroplasties, and ten hemiarthroplasties) from 2001 to 2004 was performed. Logistic regression analysis was conducted to determine which clinical variables were predictive of transfusion. RESULTS: A postoperative transfusion was received after thirty-one arthroplasties (25%). The strongest predictor of blood transfusion after shoulder arthroplasty was the preoperative hemoglobin level (likelihood ratio test = 37.8, p < 0.0001). Patients with a preoperative hemoglobin level of between 110 and 130 g/L had a five times greater estimated risk of transfusion than those with a level of >130 g/L (p < 0.001). Gender, body mass index, preoperative diagnosis, comorbid conditions, use of anticoagulants or aspirin, autologous predonation status, type of anesthesia, operative time, and decrease in hemoglobin or hematocrit were not predictors of blood transfusion. One hundred and two (78%) of the 131 predonated autologous units were discarded. Patients with a preoperative hemoglobin level of >130 g/L had the highest percentage of wasted units (90%; fifty-five of sixty-one). Preoperative autologous blood donation did not eliminate the risk of allogeneic blood transfusion in autologous donors. CONCLUSIONS: The preoperative hemoglobin level is the strongest predictor of blood transfusion after shoulder surgery, and individuals with a preoperative hemoglobin level of <110 g/L have the highest risk of transfusion. On the basis of these findings, we do not recommend autologous predonation for individuals with a preoperative hemoglobin level of >130 g/L, to avoid unnecessary expense and waste.

Adult↗
PubMed2006

Self-reported upper extremity health status correlates with depression.

BACKGROUND: The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire is the most widely used upper extremity-specific health-status measure. The DASH score often demonstrates greater variability than would be expected on the basis of objective pathology. This variability may be related to psychosocial factors. The purpose of the present study was to investigate the correlation between the DASH score and psychological factors for specific diagnoses with relatively limited variation in objective pathology. METHODS: Two hundred and thirty-five patients with a single, common, discrete hand problem known to have limited variations in objective pathology completed the DASH questionnaire, the Eysenck Personality Questionnaire-Revised (EPQ-R) to assess neuroticism, the Center for Epidemiologic Studies-Depression (CES-D) scale to quantify depressive symptoms, and the Pain Anxiety Symptoms Scale (PASS). Forty-five patients had carpal tunnel syndrome, forty-four had de Quervain tenosynovitis, forty-eight had lateral elbow pain, and seventy-one had a single trigger finger. In addition, twenty-seven patients were evaluated six weeks after a nonoperatively treated fracture of the distal part of the radius. Relationships between psychosocial factors and the DASH score were determined. RESULTS: A significant positive correlation between the DASH score and depression was noted for all diagnoses (r = 0.38 to 0.52; p < 0.01 for all). The DASH score also correlated with pain anxiety for four of the five diagnoses (carpal tunnel syndrome, r = 0.40; de Quervain tendinitis, r = 0.46; lateral elbow pain, r = 0.42; and trigger finger, r = 0.24) (p < 0.05 for all). The DASH score was not correlated with neuroticism for any diagnosis. There was a highly significant effect of depression (as measured with the CES-D score) on the DASH score for all diagnoses. Both the CES-D score (F = 62.68, p < 0.0001) and gender (F = 11.36, p < 0.001) were independent predictors of the DASH score. CONCLUSIONS: Self-reported upper extremity-specific health status as measured with the DASH score correlates with depression and pain anxiety but not neuroticism. These data support the contention that psychosocial factors have a strong influence on health-status measures.

Adult↗
PubMed2006

Two and three-dimensional computed tomography for the classification and management of distal humeral fractures. Evaluation of reliability and diagnostic accuracy.

BACKGROUND: Complex fractures of the distal part of the humerus can be difficult to characterize on plain radiographs and two-dimensional computed tomography scans. We tested the hypothesis that three-dimensional reconstructions of computed tomography scans improve the reliability and accuracy of fracture characterization, classification, and treatment decisions. METHODS: Five independent observers evaluated thirty consecutive intra-articular fractures of the distal part of the humerus for the presence of five fracture characteristics: a fracture line in the coronal plane; articular comminution; metaphyseal comminution; the presence of separate, entirely articular fragments; and impaction of the articular surface. Fractures were also classified according to the AO/ASIF Comprehensive Classification of Fractures and the classification system of Mehne and Matta. Two rounds of evaluation were performed and then compared. Initially, a combination of plain radiographs and two-dimensional computed tomography scans (2D) were evaluated, and then, two weeks later, a combination of radiographs, two-dimensional computed tomography scans, and three-dimensional reconstructions of computed tomography scans (3D) were assessed. RESULTS: Three-dimensional computed tomography improved both the intraobserver and the interobserver reliability of the AO classification system and the Mehne and Matta classification system. Three-dimensional computed tomography reconstructions also improved the intraobserver agreement for all fracture characteristics, from moderate (average kappa [kappa2D] = 0.554) to substantial agreement (kappa3D = 0.793). The addition of three-dimensional images had limited influence on the interobserver reliability and diagnostic characteristics (sensitivity, specificity, and accuracy) for the recognition of specific fracture characteristics. Three-dimensional computed tomography images improved intraobserver agreement (kappa2D = 0.62 compared with kappa3D = 0.75) but not interobserver agreement (kappa2D = 0.24 compared with kappa3D = 0.28) for treatment decisions. CONCLUSIONS: Three-dimensional reconstructions improve the reliability, but not the accuracy, of fracture classification and characterization. The influence of three-dimensional computed tomography was much more notable for intraobserver comparisons than for interobserver comparisons, suggesting that different observers see different things in the scans-most likely a reflection of the training, knowledge, and experience of the observer with regard to these relatively uncommon and complex injuries.

Adult↗
PubMed2006

Diagnosis of scaphoid fracture displacement with radiography and computed tomography.

BACKGROUND: Displacement is an important risk factor for nonunion of scaphoid wrist fractures. We compared computed tomography with radiographs with regard to their ability to detect displacement. METHODS: Six blinded observers rated thirty scaphoid fractures (ten displaced and twenty nondisplaced) with use of radiographs and computed tomography. The radiographs were evaluated separately from the computed tomography scans and then, in a third evaluation, the two imaging studies were reviewed simultaneously. The evaluations were repeated four weeks later. Observers were asked to evaluate specific measures of fracture displacement and then to judge the fracture as being displaced or nondisplaced. RESULTS: Intraobserver reliability was better for computed tomography alone and the combination of radiographs and computed tomography than it was for radiographs alone (kappa values, 0.65, 0.63, and 0.54, respectively; all p<0.001). The interobserver reliability was also better for computed tomography alone and the combination of radiographs and computed tomography than it was for radiographs alone (kappa values, 0.43, 0.48, and 0.27, respectively; all p<0.001). The average sensitivity was 75% for radiographs alone, 72% for computed tomography alone, and 80% for both; the average specificity was 64%, 80%, and 73%, respectively; the average accuracy was 68%, 77%, and 75%, respectively. The positive predictive values (assuming a 5% prevalence of fracture displacement) were low (0.10, 0.13, and 0.16) and the negative predictive values were high (0.97, 0.98, and 0.99) for the radiographs, computed tomography, and combined modality. CONCLUSIONS: Computed tomography improves the reliability of detecting scaphoid fracture displacement but has a more limited effect on accuracy, which remains <80%. The utility of computed tomography scans for diagnosing scaphoid fracture displacement is affected by the low prevalence of fracture displacement. This study suggests that computed tomography scans are useful for ruling out displacement but not for diagnosing it. We recommend that all scaphoid fractures be evaluated with computed tomography in order to rule out displacement.

Fractures, Bone↗
PubMed2006

Appendicitis in young children: imaging experience and clinical outcomes.

OBJECTIVE: Our purpose was to evaluate the imaging characteristics and clinical outcomes of children less than 5 years old who underwent surgery for presumed appendicitis. CONCLUSION: Appendicitis is not rare in young children and imaging findings reflect the high frequency of perforation in this population.

Adolescent↗
PubMed2006

Ultrasound diagnosis of mouse pregnancy and gestational staging.

Phenotypic analysis of mutant mice is limited by lack of accurate, simple, and nondestructive in utero imaging techniques. This study evaluated the usefulness of ultrasound imaging (US) to stage fetal mouse gestational age (GA) and depict morphologic development. We imaged 16 pregnant CD-1 mice and a total of 92 fetuses with a 15-MHz US transducer from 9.5 d postcoitus (DPC) until 20.5 DPC or delivery. Parameters recorded included gestational sac dimensions, crown-rump length (CRL), biparietal diameter (BPD), thoracoabdominal diameter (TAD), onset of cardiac activity, and morphologic development. At 9.5 d DPC, all gestations appeared as rounded sacs, with a diameter (mean +/- standard error) of 4.4 +/- 1 mm. BPD, CRL, and GA were highly correlated. The following structures were first identifiable at the following GA: cardiac activity, 10.5 DPC; major cardiovascular structures, 11.5 DPC; limb buds, 10.5 DPC; spine, 12.5 DPC; face and skull ossification, 13.5 DPC; rib ossification, 15.5 DPC; hind- and forelimb digits, 15.5 DPC; stomach and urinary bladder, 17.5 DPC; visualization of the rhombencephalic vesicle, 13.5 DPC; and visualization of the lateral ventricles, 14.5 DPC. The echogenic lungs were distinct from the liver as early as 12.5 DPC. The circle of Willis was detectable with color Doppler as early as 13.5 DPC and was easily visualized at 15.5 DPC. We found that US provides accurate, simple staging criteria for fetal mouse gestational development after 9.5 DPC and may be a nondestructive means of documenting phenotypic alterations in mutant mice in utero.

Animals↗
PubMed2005

Prediction of thoracic dimensions and spine length based on individual pelvic dimensions in children and adolescents: an age-independent, individualized standard for evaluation of outcome in early onset spinal deformity.

STUDY DESIGN: A retrospective review of spine, chest, and pelvic dimensions of normal CT scans from 1999 to 2004 was performed. OBJECTIVE: To determine age-independent predictors of spine and chest dimensions. SUMMARY OF BACKGROUND DATA: Progressive thoracic deformity is associated with early-onset spinal deformities. Patients with severe early-onset scoliosis are commonly smaller and slower to grow than normal. Newer treatment approaches emphasize spine length and chest growth. Assessing treatment outcomes is hampered by the lack of normal values appropriate for diseased children. This study establishes normal range standards of chest and spine dimensions to aid in assessment of treatment outcomes. METHODS: A total of 198 CT scans of previously healthy patients 0 to 21 years of age were measured. Measurements taken from CT scans include maximum inner chest width, anteroposterior chest depth, thoracic spine height, lumbar spine height, total spine height, and pelvic inlet width. Linear regression was applied to establish gender-specific reference ranges for spine and chest dimensions based on pelvic width. RESULTS: Chest and spine dimensions were significantly correlated with pelvic inlet width and gender (P < 0.001). Multiple linear regression indicated that pelvic inlet width provided excellent fit in establishing gender-specific normal ranges independent of age. CONCLUSION: Pelvic inlet width is an age-independent predictor of pediatric chest width and thoracic dimensions that may be used to assess thoracic and spine growth in early onset spine deformity patients.

Adolescent↗
PubMed2005

Neuroprotective effects of cardiotrophin-like cytokine on retinal ganglion cells.

BACKGROUND: Premature neuronal cell death is a feature of numerous central nervous system and eye diseases, including glaucoma. Neurons (including retinal ganglion cells, RGCs) are protected by several neurotrophic factors, among those the IL-6 family of cytokines. Lately, a novel member of the IL-6 family of cytokines has been identified and cloned. This cytokine is known as novel neurotrophin-1/B-cell-stimulating factor-3 (NNT-1/BSF-3) or cardiotrophin-like cytokine (CLC). It shows neurotrophic as well as B-cell stimulatory effects. METHODS: In this study, the neuroprotective properties of CLC on RGC loss in vivo were investigated. RESULTS: CLC significantly protected RGCs from degeneration in both chosen models of retinal neuronal damage: optic nerve crush (P<0.01) and N-methyl-D-aspartate (NMDA) injection (P<0.001). CONCLUSIONS: CLC shows neuroprotective effects on RGCs in vivo and might be a treatment option for chronic neurodegenerative eye diseases such as glaucoma. Clinical feasibility for the substance requires further investigation since the immunomodulatory and possible adverse effects have not yet been thoroughly characterized.

Animals↗
PubMed2005

Ross procedure and left ventricular mass regression.

BACKGROUND: Return of left ventricular mass to normal is considered to be a favorable result of aortic valve replacement. The Ross procedure provides near normal hemodynamics and thus allows studies of left ventricular (LV) reverse remodeling. LV mass regression may be influenced by surgical technique (subcoronary [SC] versus root replacement [RR]). METHODS AND RESULTS: Data from the German Ross Registry were analyzed. A total of 646 patients (mean age: 43.6+/-12.7 years, range: 16 to 71 years; SC technique n=295, RR technique n=351) underwent a Ross procedure in 7 participating centers from 1990 to 2004. The patients underwent preoperative and postoperative echocardiographic evaluations. Mean follow-up time was 3.5+/-2.5 years (range 0.12 to 13.7 years). Follow-up completeness was 97%. The LV mass index (LVMI) decreased significantly during follow-up in both groups (SC: 209+/-53 preoperatively to 154+/-48 at 1-year follow-up, [P<0.01 versus preoperative values] to 149+/-51 g/m2 at 2-year follow-up, [P=NS 1-year versus 2-year follow-up] versus RR: from 195+/-56 preoperatively to 144+/-51 at 1-year follow-up [P<0.01 versus preoperative values] to 140+/-49 g/m2 [P=NS 1-year versus 2-year follow-up]). LVMI regression remained stagnant 1 year after the Ross procedure in most patients in both groups. On the basis of multivariate analysis, predictors for incomplete LVMI regression after the autograft procedure were high preoperative LVMI, smoking, and uncontrolled diastolic hypertension. CONCLUSIONS: At mid-term echocardiographic follow-up, patients of both groups had favorable autograft hemodynamics. Risk factors for incomplete postoperative LVMI regression in our study were smoking and persistent diastolic hypertension. This emphasizes the importance of cessation of smoking and treatment of arterial hypertension, even in younger patients, after corrected aortic valve disease.

Adolescent↗
PubMed2005

Autologous chondrocyte implantation versus debridement for treatment of full-thickness chondral defects of the knee: an observational cohort study with 3-year follow-up.

BACKGROUND: Studies that compare the effectiveness of different cartilage repair treatments are needed to update treatment algorithms. HYPOTHESIS: Autologous chondrocyte implantation provides greater improvement in overall condition score than does debridement at a minimum of 3 years' follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Cohorts for debridement and autologous chondrocyte implantation each included 58 Cartilage Repair Registry patients who met study criteria. A retrospective analysis was performed on prospectively collected baseline and follow-up data. RESULTS: Patients in the autologous chondrocyte implantation and debridement groups had similar demographics and chondral lesions at baseline. However, more autologous chondrocyte implantation patients failed a previous debridement or marrow stimulation procedure than did debridement patients. Follow-up outcome assessments were completed by 54 autologous chondrocyte implantation patients and 42 debridement patients. Eighty-one percent of the autologous chondrocyte implantation patients and 60% of the debridement patients reported median improvements of 5 points and 2 points, respectively, in the overall condition score. Autologous chondrocyte implantation patients also reported greater improvements in the median pain and swelling scores than did debridement patients. The treatment failure rate was the same for both autologous chondrocyte implantation and debridement patients. Eighteen autologous chondrocyte implantation patients and 1 debridement patient had at least 1 subsequent operation. CONCLUSION: Although patients treated with debridement for symptomatic, large, focal, chondral defects of the distal femur had some functional improvement at follow-up, patients who received autologous chondrocyte implantations obtained higher levels of knee function and had greater relief from pain and swelling at 3 years.

Adult↗
PubMed2005

Serum levels of nickel and chromium after instrumented posterior spinal arthrodesis.

STUDY DESIGN: Cross-sectional study of 37 patients to measure serum levels of nickel and chromium after posterior spinal arthrodesis using stainless steel implants. OBJECTIVES: To investigate the relationship between factors such as age, gender, pain, time from surgery, length of arthrodesis, and level of arthrodesis to serum metal ion levels after instrumented spinal arthrodesis. SUMMARY OF BACKGROUND DATA: Measurable levels of metal ions in the serum can be detected after the use of stainless steel implants. There is some evidence to suggest that long-term exposure can potentially be toxic. Posterior spinal arthrodesis with stainless steel implants is a common procedure to treat spinal deformity in the adolescent population; however, the extent of metal ion exposure after posterior spinal arthrodesis is unknown. METHODS: Patients that underwent posterior instrumented spinal arthrodesis with more than 6 months follow-up were recruited for this study. Patients with altered neurologic function were excluded. Serum levels of nickel and chromium were measured using inductively coupled plasma mass spectrometry. Pain was assessed using the Oswestry questionnaire. Spine radiographs were used to look for evidence of pseudarthrosis. Forty-five patients were approached, and 37 agreed to the questionnaire and blood test. Ten patients were men and 27 were women. Mean age at surgery was 14 years with mean follow-up of 6 years. Statistical correlations between serum metal ion levels and age at surgery, time from surgery, gender, number of segments fused, spinal instrument interfaces, pain, and instrumentation type were assessed. RESULTS: Abnormally high levels of nickel and chromium above normal levels (0.3 ng/mL for nickel, 0.15 ng/mL for chromium) could be detected in serum after posterior spinal arthrodesis using stainless steel implants. There was a significant inverse correlation between serum nickel (r = -0.61, P < 0.001) and chromium (r = -0.64, P < 0.001) levels and time from surgery. When patients were grouped based on lengths of time from surgery, 0 to 2 years (n = 7), 2 to 4 years (n = 11), and >4 years (n = 8), the mean +/- SD for nickel (ng/mL) was 3.8 +/- 2.6, 1.3 +/- 1.1, and 0.9 +/- 0.8, respectively. Analysis ofvariance revealed significant group differences (P =0.004). Similarly, the chromium levels were 2.7 +/- 2.7, 0.6 +/- 0.4, and 0.3 +/- 0.3, respectively (P = 0.018). Only time from surgery was a significant multivariate predictor of nickel and chromium serum levels. Pseudarthrosis was not seen in this cohort. CONCLUSIONS: Elevated levels of nickel and chromium can be measured after posterior instrumented spinal arthrodesis. The levels diminish rapidly with time from surgery but still remained above normal levels 4 years after surgery. Long-term implication of this metal ion exposure is unknown and should be studied further.

Adolescent↗