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255 result(s) for "Akbar, Michael"
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3D-modeling of the spine using EOS imaging system: Inter-reader reproducibility and reliability
To retrospectively assess the interreader reproducibility and reliability of EOS 3D full spine reconstructions in patients with adolescent idiopathic scoliosis (AIS). 73 patients with mean age of 17 years and a moderate AIS (median Cobb Angle 18.2°) obtained low-dose standing biplanar radiographs with EOS. Two independent readers performed \"full spine\" 3D reconstructions of the spine with the \"full-spine\" method adjusting the bone contour of every thoracic and lumbar vertebra (Th1-L5). Interreader reproducibility was assessed regarding rotation of every single vertebra in the coronal (i.e. frontal), sagittal (i.e. lateral), and axial plane, T1/T12 kyphosis, T4/T12 kyphosis, L1/L5 lordosis, L1/S1 lordosis and pelvic parameters. Radiation exposure, scan-time and 3D reconstruction time were recorded. Interclass correlation (ICC) ranged between 0.83 and 0.98 for frontal vertebral rotation, between 0.94 and 0.99 for lateral vertebral rotation and between 0.51 and 0.88 for axial vertebral rotation. ICC was 0.92 for T1/T12 kyphosis, 0.95 for T4/T12 kyphosis, 0.90 for L1/L5 lordosis, 0.85 for L1/S1 lordosis, 0.97 for pelvic incidence, 0.96 for sacral slope, 0.98 for sagittal pelvic tilt and 0.94 for lateral pelvic tilt. The mean time for reconstruction was 14.9 minutes (reader 1: 14.6 minutes, reader 2: 15.2 minutes, p<0.0001). The mean total absorbed dose was 593.4μGy ±212.3 per patient. EOS \"full spine\" 3D angle measurement of vertebral rotation proved to be reliable and was performed in an acceptable reconstruction time. Interreader reproducibility of axial rotation was limited to some degree in the upper and middle thoracic spine due the obtuse angulation of the pedicles and the processi spinosi in the frontal view somewhat complicating their delineation.
Elevated Serum Insulin-Like Growth Factor 1 Levels in Patients with Neurological Remission after Traumatic Spinal Cord Injury
After traumatic spinal cord injury, an acute phase triggered by trauma is followed by a subacute phase involving inflammatory processes. We previously demonstrated that peripheral serum cytokine expression changes depend on neurological outcome after spinal cord injury. In a subsequent intermediate phase, repair and remodeling takes place under the mediation of growth factors such as Insulin-like Growth Factor 1 (IGF-1). IGF-1 is a promising growth factor which is thought to act as a neuroprotective agent. Since previous findings were taken from animal studies, our aim was to investigate this hypothesis in humans based on peripheral blood serum. Forty-five patients after traumatic spinal cord injury were investigated over a period of three months after trauma. Blood samples were taken according to a fixed schema and IGF-1 levels were determined. Clinical data including AIS scores at admission to the hospital and at discharge were collected and compared with IGF-1 levels. In our study, we could observe distinct patterns in the expression of IGF-1 in peripheral blood serum after traumatic spinal cord injury regardless of the degree of plegia. All patients showed a marked increase of levels seven days after injury. IGF-1 serum levels were significantly different from initial measurements at four and nine hours and seven and 14 days after injury, as well as one, two and three months after injury. We did not detect a significant correlation between fracture and the IGF-1 serum level nor between the quantity of operations performed after trauma and the IGF-1 serum level. Patients with clinically documented neurological remission showed consistently higher IGF-1 levels than patients without neurological remission. This data could be the base for the establishment of animal models for further and much needed research in the field of spinal cord injury.
CT-Guided Biopsy in Suspected Spondylodiscitis – The Association of Paravertebral Inflammation with Microbial Pathogen Detection
To search for imaging characteristics distinguishing patients with successful from those with futile microbiological pathogen detection by CT-guided biopsy in suspected spondylodiscitis. 34 consecutive patients with suspected spondylodiscitis underwent CT-guided biopsy for pathogen detection. MR-images were assessed for inflammatory infiltration of disks, adjacent vertebrae, epidural and paravertebral space. CT-images were reviewed for arrosion of adjacent end plates and reduced disk height. Biopsy samples were sent for microbiological examination in 34/34 patients, and for additional histological analysis in 28/34 patients. Paravertebral infiltration was present in all 10/10 patients with positive microbiology and occurred in only 12/24 patients with negative microbiology, resulting in a sensitivity of 100% and a specificity of 50% for pathogen detection. Despite its limited sensitivities, epidural infiltration and paravertebral abscesses showed considerably higher specificities of 83.3% and 90.9%, respectively. Paravertebral infiltration was more extensive in patients with positive as compared to negative microbiology (p = 0.002). Even though sensitivities for pathogen detection were also high in case of vertebral and disk infiltration, or end plate arrosion, specificities remained below 10%. Inflammatory infiltration of the paravertebral space indicated successful pathogen detection by CT-guided biopsy. Specificity was increased by the additional occurrence of epidural infiltration or paravertebral abscesses.
Could long-term overhead load in painters be associated with rotator cuff lesions? A pilot study
Use of the arm above shoulder level has been described as a risk factor for developing rotator cuff tears (RCT). There is a lack of information regarding the frequency and distribution of RCT in a population using their arms above shoulder level during daily work. The aim of this study was to analyze clinical and radiographic findings in a population of painters working more than 10 years and to compare the results with a control group (CG). 100 individuals working more than 10 years as a painter were compared to 100 matched controls without using their arms above shoulder level. MRI scans were performed in all participants. Clinically, the Constant score, DASH score and range of motion (ROM) of the shoulders were analyzed. In the painter group (PG) a tear of the supraspinatus tendon was detected in 45% (10%full-thickness; 35% partial) compared to 8% in the (CG) (3% full-thickness; 5%partial; p<0.001). Impingement test was painful in 52% of PG and 7% of CG (p<0.001). The Constant score in the PG was significantly lower compared to the CG (62 vs. 93 points; p<0.001). PG had significantly worse DASH scores and inferior active and passive ROM of the dominant shoulders. In the multivariable logistic regression analysis, three risk factors (smoking, sports activity, and handedness) showed no effect. However, group membership (PG/CG) and age revealed a significant effect. Long-term occupational load on the shoulders in painters seems to be associated with an increased risk for developing RCT. Our findings may provide support for developing preventive strategies for this unique cohort. Level of evidence: III.
Surgical site infections following instrumented stabilization of the spine
Implant-associated infections are still a feared complication in the field of orthopedics. Bacteria attach to the implant surface and form so-called biofilm colonies that are often difficult to diagnose and treat. Since the majority of studies focus on prosthetic joint infections (PJIs) of the hip and knee, current treatment options (eg, antibiotic prophylaxis) of implant-associated infections have mostly been adapted according to these results. The aim of this study was to evaluate patients with surgical site infections following instrumented stabilization of the spine with regard to detected bacteria species and the course of the disease. We performed a retrospective single-center analysis of implant-associated infections of the spine from 2010 to 2014. A total of 138 patients were included in the study. The following parameters were evaluated: C-reactive protein serum concentration, microbiological evaluation of tissue samples, the time course of the disease, indication for instrumented stabilization of the spine, localization of the infection, and the number of revision surgeries required until cessation of symptoms. Coagulase-negative spp. were most commonly detected (n=69, 50%), followed by fecal bacteria (n=46, 33.3%). In 23.2% of cases, no bacteria were detected despite clinical suspicion of an infection. Most patients suffered from degenerative spine disorders (44.9%), followed by spinal fractures (23.9%), non-degenerative scoliosis (20.3%), and spinal tumors (10.1%). Surgical site infections occurred predominantly within 3 months (64.5%), late infections after 2 years were rare (4.3%), in particular when compared with PJIs. Most cases were successfully treated after 1 revision surgery (60.9%), but there were significant differences between bacteria species. Fecal bacteria were more difficult to treat and often required more than 1 revision surgery. In summary, we were able to demonstrate significant differences between spinal implant-associated infections and PJIs. These aspects should be considered early on in the treatment of surgical site infections following instrumented stabilization of the spine.
Risk of dislocation using large- vs. small-diameter femoral heads in total hip arthroplasty
Background Dislocation remains a difficult problem in total hip arthroplasty. Large-diameter femoral heads may lower the incidence of dislocation by enhancing the jump distance and decreasing impingement, but their performance against small-diameter heads has not been assessed. This study compared the mid-term radiographic and functional outcomes of two matched cohorts of patients undergoing total hip arthroplasty who had a high pre-operative risk for dislocation and who received either small-diameter (26- or 28-millimeters) or large-diameter (≥36-millimeters) femoral heads. Methods All patients who received large-diameter heads (≥36-millimeter) between 2002 and 2005, and who had pre-operative risk factors for dislocation, were identified in the institution’s joint registry. Forty-one patients (52 hips) who received large-diameter heads were identified, and these patients were matched to 48 patients (52 hips) in the registry who received small-diameter femoral heads. Results At mean final follow-up of 62 months (range, 49 to 101 months), both groups achieved excellent functional outcomes as measured by Harris Hip scores, with slightly better final scores in the large-diameter group (90 vs. 83 points). No patient showed any radiographic signs of loosening. No patient dislocated in the large-diameter femoral head group; the smaller-diameter group had a greater rate of dislocation (3.8%, 2 out of 52). Conclusions Large-diameter femoral head articulations may reduce dislocation rates in patients who have a high pre-operative risk for dislocation while providing the same functional improvements and safety as small-diameter bearings.
Proposition of a protocol to evaluate upper-extremity functional deficits and compensation mechanisms: application to elbow contracture
Instrumented gait analysis is widely acceptedas an objective assessment of lower-extremity function. Conversely, upper-extremity function suffers from lack of objective evaluation. The present paper aims at proposing a protocol to be used to clinically and objectively evaluate upper-extremity function whatever the pathological joint. Secondly, it aims at better understanding the consequences on upper-extremity function and the compensation mechanisms induced by elbow contracture. Elbow contracture was simulated in this study by using a brace. Twelve healthy subjects followed an instrumented3D movement analysis while performing 11 daily life movements. The movements were performed with 3 differentelbow contracture conditions, simulated by wearing an adjustable elbow brace. The proposed protocol was successful in creatinga wide range of motion at all the upper-extremity joints. The activity-related range of motion and the mean range of motion computed on the whole set of daily life movements were effective in evaluating the severity of elbow contracture. The lack of elbow flexion was compensated by trunk flexion, hand flexion and radial deviation, and combined movement of shoulder flexion, abduction, and humeral internal rotation. Deficit in elbow extension was mainly compensated by the use of trunk flexion. A protocol could be proposed for the objectiveevaluation of upper-extremity function. Its application to elbow contracture suggests that loss of elbow flexion affects more movements than loss of elbow extension.
Biomechanical Study of a Novel, Expandable, Non-Metallic and Radiolucent CF/PEEK Vertebral Body Replacement (VBR)
Vertebral body replacement is well-established to stabilize vertebral injuries due to trauma or cancer. Spinal implants are mainly manufactured by metallic alloys; which leads to artifacts in radiological diagnostics; as well as in radiotherapy. The purpose of this study was to evaluate the biomechanical data of a novel carbon fiber reinforced polyetheretherketone (CF/PEEK) vertebral body replacement (VBR). Six thoracolumbar specimens were tested in a six degrees of freedom spine tester. In all tested specimens CF/PEEK pedicle screws were used. Two different rods (CF/PEEK versus titanium) with/without cross connectors and two different VBRs (CF/PEEK prototype versus titanium) were tested. In lateral bending and flexion/extension; range of motion (ROM) was significantly reduced in all instrumented states. In axial rotation; the CF/PEEK combination (rods and VBR) resulted in the highest ROM; whereas titanium rods with titanium VBR resulted in the lowest ROM. Two cross connectors reduced ROM in axial rotation for all instrumentations independently of VBR or rod material. All instrumented states in all planes of motion showed a significantly reduced ROM. No significant differences were detected between the VBR materials in all planes of motion. Less rigid CF/PEEK rods in combination with the CF/PEEK VBR without cross connectors showed the smallest reduction in ROM. Independently of VBR and rod material; two cross connectors significantly reduced ROM in axial rotation. Compared to titanium rods; the use of CF/PEEK rods results in higher ROM. The stiffness of rod material has more influence on the ROM than the stiffness of VBR material.
Tracking Spinal Cord Injury: Differences in Cytokine Expression of IGF-1, TGF- B1, and sCD95l Can Be Measured in Blood Samples and Correspond to Neurological Remission in a 12-Week Follow-Up
Neuroinflammation presumably has an important impact on the secondary phase of spinal cord injury and is regulated by pro- and anti-inflammatory cytokines. We analyzed serum levels of three different cytokines (insulin-like-growth-factor [IGF]-1, tumor growth factor [TGF]-β1, and soluble CD 95 ligand [sCD95L]), in blood samples of 23 patients admitted with acute traumatic spinal cord injury between November 2010 and July 2013 with a follow-up period of 12 weeks. Quantification was performed using Human Quantikine Immunoassays, classification of neurological impairment was performed using the American Spinal Cord Injury Impairment Scale at time of admission and after 12 weeks. After an initial drop of all three cytokine serum levels, IGF-1, TGF-β1, and sCD95L showed significantly increased serum levels during the acute and sub-acute phases. For IGF-1 and sCD95L, we could also observe significantly higher serum levels in patients without neurological improvement compared with patients who had improvement after 12 weeks. In this study, we were able to show differences in cytokine serum levels in patients with different neurological outcome. Measuring the serum level patterns of IGF-1, TGF-β1, and sCD95L might be a useful tool for prognosis in patients with neurological improvement and tracking the pathophysiology in further studies. Further, our observations might link promising therapeutic efforts in numerous animal studies and future studies in human patients.