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Sökning: WFRF:(Ohlin Acke)

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11.
  • Abul-Kasim, Kasim, et al. (författare)
  • Radiological and clinical outcome of screw placement in adolescent idiopathic scoliosis: evaluation with low-dose computed tomography.
  • 2010
  • Ingår i: European Spine Journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 19:1, s. 96-104
  • Tidskriftsartikel (refereegranskat)abstract
    • Posterior corrective surgery using "all pedicle screw construct" carries risk of neurovascular complications. The study aims were to assess the screw placement in patients with adolescent idiopathic scoliosis using CT with low-radiation dose, and to evaluate the clinical outcome in patients with misplaced pedicle screws. CTs of 49 consecutive patients (873 screws, 79% thoracic) were retrospectively evaluated by two independent radiologists. A new grading system was developed to distinguish between lateral, medial and anterior cortical perforations, endplate perforation and foraminal perforation. The grading system is based on whether the cortical violation is partial or total rather than on mm-basis. The overall rate of screw misplacement was 17% (n = 149): 8% were laterally placed and 6.1% were medially placed. The rates of anterior cortical, endplate and foraminal perforation were 1.5, 0.9, and 0.5%, respectively. Lateral cortical perforation was more frequent in the thoracic spine (P = 0.005), whereas other types of misplacement including medial cortical perforation were more frequent on the left and the concave side of scoliotic curves (P = 0.002 and 0.003). No neurovascular complications were reported. The association between the occurrence of screw misplacement and the Cobb angle was statistically significant (P = 0.037). Misplacements exceeding half screw diameter should be classified as unacceptable. Low-dose CT implies exposing these young individuals to a significantly lower radiation dose than do other protocols used in daily clinical practice. We recommend using low-dose CT and the grading system proposed here in the postoperative assessment of screw placement.
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12.
  • Abul-Kasim, Kasim, et al. (författare)
  • Reliability of Low-Radiation Dose CT in the Assessment of Screw Placement After Posterior Scoliosis Surgery, Evaluated With a New Grading System
  • 2009
  • Ingår i: Spine. - 0362-2436. ; 34:9, s. 941-948
  • Tidskriftsartikel (refereegranskat)abstract
    • Study Design. A retrospective study. Objective. To evaluate the reliability of computed tomography (CT) with low radiation dose in the assessment of implant status in patients with adolescent idiopathic scoliosis (AIS). Summary of Background Data. The use of all-pedicle screw construct in scoliosis corrective surgery continues to gain increasing popularity since their introduction 1994 although their use in the thoracic spine carries a potential risk for neurovascular complications. CT is the method widely used to evaluate screw placement. Methods. Retrospective analysis of 46 consecutive low-dose spine CT in patients with AIS after posterior corrective surgery. Status of 809 titanium screws (642 thoracic) was evaluated. The degree of interobserver and intraobserver agreements about implant status was used as an indicator of the reliability of the low-dose spine CT in the assessment of accuracy of pedicle screw insertion. A new grading system has been developed for this purpose. Five types of misplacement have been evaluated: lateral, medial, and anterior cortical perforations; end-plate perforation; and foraminal perforation. Results. The analysis has shown a substantial interobserver and intraobserver agreements (kappa: 0.69 and 0.76, respectively) in differentiating pedicle screws with acceptable placement from screws with partial or total cortical perforation. None of the examinations was subjectively classified as unreliable. Conclusion. The study has shown that low-dose spine CT is a reliable method in evaluating screw placement in patients with AIS after posterior scoliosis surgery with titanium implants, using the here proposed grading system. The new grading system of screw misplacement was feasible and in line with the general agreement about the harmlessness of misplacement with minor pedicle breach. The reliability of low-dose spine CT in evaluation of lateral and medial cortical perforations was substantial. To reduce the radiation load, the postoperative assessment of titanium implants should be performed with low-dose CT.
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13.
  • Abul-Kasim, Kasim, et al. (författare)
  • Spinal Epidural Lipomatosis: A Common Imaging Feature in Scheuermann Disease.
  • 2012
  • Ingår i: Journal of Spinal Disorders and Techniques. - 1539-2465. ; 25:7, s. 356-361
  • Tidskriftsartikel (refereegranskat)abstract
    • STUDY DESIGN: Retrospective study. OBJECTIVES: To find out if spinal epidural lipomatosis (SEL) occurs more commonly among patients with Scheuermann disease than in the general population. SUMMARY AND BACKGROUND: On the basis of our own radiologic and operative observation, SEL seems to occur frequently in patients with Scheuermann disease. METHODS: Magnetic resonance imaging of 87 individuals (72% male, average age 19±6 y) from 2 centers (29 consecutive patients with Scheuermann disease and 58 controls) were retrospectively evaluated by 2 neuroradiologists. Spinal epidural fat (EF) at seventh thoracic vertebra (EF7), maximum EF (EFmax), dural sac diameter at T7 and at the level of maximum EF (DS7 and DSmax) were measured. EF ratios at T7 (EFR7) and at maximum EF (EFRmax) were calculated as EF/DS. Body mass index (BMI) for study population and kyphosis severity for the patients were recorded. Mann-Whitney, Spearman correlation, and χ tests were performed dependent on the variable in question. RESULTS: EF7, DS7, EFmax, EFR7, and EFRmax was significantly higher among patients with Scheuermann disease (EFmax 5.7±2.4 mm) than among controls (EFmax 3.8±1.1 mm), P<0.001. Twelve patients with Scheuermann disease (41%) fulfilled our proposed criteria for the diagnosis of SEL (EFmax>6 mm+EFRmax>0.51) compared with 2 (3%) among controls (P<0.001). Patients with Scheuermann disease exhibited higher BMI than controls (24.9±5 kg/m vs. 22.9±4 kg/m, P=0.138). Logistic regression showed that the occurrence of SEL among patients with Scheuermann disease was independent of BMI (P=0.880). The degree of kyphosis in patients with Scheuermann's disease (62±20°) was correlated to the amount of the EF. CONCLUSIONS: As SEL occurs more frequently among patients with Scheuermann disease, spine magnetic resonance imaging should be routinely performed to screen each of these patients to avoid impending neurological injury during surgery, especially in those exhibiting SEL.
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14.
  • Abul-Kasim, Kasim, et al. (författare)
  • The rate of screw misplacement in segmental pedicle screw fixation in adolescent idiopathic scoliosis.
  • 2011
  • Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3682 .- 1745-3674. ; 82, s. 50-55
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and purpose There are no reports in the literature on the influence of learning on the pedicle screw insertion. We studied the effect of learning on the rate of screw misplacement in patients with adolescent idiopathic scoliosis treated with segmental pedicle screw fixation. Method We retrospectively evaluated low-dose spine computed tomography of 116 consecutive patients (aged 16 (12-24) years, 94 females) who were operated during 4 periods over 2005-2009 (group 1: patients operated autumn 2005-2006; group 2: 2007; group 3: 2008; and group 4: 2009). 5 types of misplacement were recorded: medial cortical perforation, lateral cortical perforation, anterior cortical perforation of the vertebral body, endplate perforation, and perforation of the neural foramen. Reslts 2,201 pedicle screws were evaluated, with an average of 19 screws per patient. The rate of screw misplacement for the whole study was 14%. The rate of lateral and medial cortical perforation was 7% and 5%. There was an inverse correlation between the occurrence of misplacement and the patient number, i.e. the date of operation (r = -0.35; p < 0.001). The skillfulness of screw insertion improved with reduction of the rate of screw misplacement from 20% in 2005-2006 to 11% in 2009, with a breakpoint at the end of the first study period (34 patients). Interpretation We found a substantial learning curve; cumulative experience may have contributed to continued reduction of misplacement rate.
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15.
  • Abul-Kasim, Kasim, et al. (författare)
  • Tonsillar ectopia in idiopathic scoliosis: does it play a role in the pathogenesis and prognosis or is it only an incidental finding?
  • 2009
  • Ingår i: Scoliosis. - : Springer Science and Business Media LLC. - 1748-7161. ; 4, s. 1-7
  • Tidskriftsartikel (refereegranskat)abstract
    • ABSTRACT: BACKGROUND: There is an ongoing controversy about the significance of tonsillar ectopia among patients with idiopathic scoliosis (IS). AIM: To find out if tonsillar ectopia occurs more frequently among patients with IS and if it plays any etiological or prognostic role in IS. STUDY DESIGN: Retrospective study. METHODS: Retrospective analysis of 155 consecutive spine MRIs (79 patients with IS and 76 controls; aged 7-25 years; 55% were female) with regard to the position of the cerebellar tonsils in relation to foramen magnum and the sagittal diameter of foramen magnum. All images were evaluated independently by two neuroradiologists. Interobserver and intraobserver reliability analysis was performed by calculation of kappa-value, intraclass correlation coefficient, and systematic and random errors. The occurrence of tonsillar ectopia among patients with IS and controls was estimated and the association of tonsillar ectopia with different predictors has been tested. Statistical significance was set to P
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16.
  • Abul-Kasim, Kasim, et al. (författare)
  • Vertebral Hemangiomas : Prevalence, New Classification and Natural History. Magnetic Resonance Imaging-Based Retrospective Longitudinal Study
  • 2023
  • Ingår i: Neuroradiology Journal. - : SAGE Publications. - 1971-4009 .- 2385-1996. ; 36:1, s. 23-30
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and purpose: To determine the prevalence of vertebral hemangiomas (VHs), establish a new classification of VHs based on their MRI-signal pattern, and study their natural history. Methods: MRI of 1000 consecutive patients who underwent at least two MRI with an interval of at least 3 years. Growth rate and change of MRI-signal pattern during the follow-up period were the parameters included in studying the natural history of VHs. Results: The prevalence of VHs was 41%. VHs were classified as type I–IV with fat-rich VHs (type I), constituted 79% of all VHs. VHs were more common among females 43% versus males 39%, p =.22. The most affected vertebra was L1. Occurrence rates for cervical (1%), thoracic (7%), and lumbar spine (10%) differed significantly (p <.001). The prevalence of VHs increased with age regardless of gender or spinal part involved (p <.001). Only 26% of VHs changed their size and 4% changed their signal during the average follow-up of 7 years. All VHs were slowly growing lesions (average expected growth of <3 mm/10 years). No significant difference between growth rate of VHs type I (0.25 mm/year) and other types of VHs. None of the VHs that were initially reported as “metastases cannot be rule out” showed alarming change in signal or size. Conclusions: VH can be classified into four types based on their MRI-signal pattern. Regardless of their type, VHs are slowly growing lesions. The presence of typical morphological pattern should enable radiologists to confidently differentiate them from vertebral metastases.
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17.
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18.
  • Andersson, Martin K, et al. (författare)
  • Effects on osteoclast and osteoblast activities in cultured mouse calvarial bones by synovial fluids from patients with a loose joint prosthesis and from osteoarthritis patients.
  • 2007
  • Ingår i: Arthritis research & therapy. - : Springer Science and Business Media LLC. - 1478-6362 .- 1478-6354. ; 9:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Aseptic loosening of a joint prosthesis is associated with remodelling of bone tissue in the vicinity of the prosthesis. In the present study, we investigated the effects of synovial fluid (SF) from patients with a loose prosthetic component and periprosthetic osteolysis on osteoclast and osteoblast activities in vitro and made comparisons with the effects of SF from patients with osteoarthritis (OA). Bone resorption was assessed by the release of calcium 45 (45Ca) from cultured calvariae. The mRNA expression in calvarial bones of molecules known to be involved in osteoclast and osteoblast differentiation was assessed using semi-quantitative reverse transcription-polymerase chain reaction (PCR) and real-time PCR. SFs from patients with a loose joint prosthesis and patients with OA, but not SFs from healthy subjects, significantly enhanced 45Ca release, effects associated with increased mRNA expression of calcitonin receptor and tartrate-resistant acid phosphatase. The mRNA expression of receptor activator of nuclear factor-kappa-B ligand (rankl) and osteoprotegerin (opg) was enhanced by SFs from both patient categories. The mRNA expressions of nfat2 (nuclear factor of activated T cells 2) and oscar (osteoclast-associated receptor) were enhanced only by SFs from patients with OA, whereas the mRNA expressions of dap12 (DNAX-activating protein 12) and fcrgamma (Fc receptor common gamma subunit) were not affected by either of the two SF types. Bone resorption induced by SFs was inhibited by addition of OPG. Antibodies neutralising interleukin (IL)-1alpha, IL-1beta, soluble IL-6 receptor, IL-17, or tumour necrosis factor-alpha, when added to individual SFs, only occasionally decreased the bone-resorbing activity. The mRNA expression of alkaline phosphatase and osteocalcin was increased by SFs from patients with OA, whereas only osteocalcin mRNA was increased by SFs from patients with a loose prosthesis. Our findings demonstrate the presence of a factor (or factors) stimulating both osteoclast and osteoblast activities in SFs from patients with a loose joint prosthesis and periprosthetic osteolysis as well as in SFs from patients with OA. SF-induced bone resorption was dependent on activation of the RANKL/RANK/OPG pathway. The bone-resorbing activity could not be attributed solely to any of the known pro-inflammatory cytokines, well known to stimulate bone resorption, or to RANKL or prostaglandin E2 in SFs. The data indicate that SFs from patients with a loose prosthesis or with OA stimulate bone resorption and that SFs from patients with OA are more prone to enhance bone formation.
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19.
  • Brink, Rob C., et al. (författare)
  • Three-dimensional pelvic incidence is much higher in (thoraco)lumbar scoliosis than in controls
  • 2019
  • Ingår i: European spine journal. - Heidelberg : Springer. - 0940-6719 .- 1432-0932. ; 28:3, s. 544-550
  • Tidskriftsartikel (refereegranskat)abstract
    • PurposeThe pelvic incidence (PI) is used to describe the sagittal spino-pelvic alignment. In previous studies, radiographs were used, leading to less accuracy in establishing the three-dimensional (3D) spino-pelvic parameters. The purpose of this study is to analyze the differences in the 3D sagittal spino-pelvic alignment in adolescent idiopathic scoliosis (AIS) subjects and non-scoliotic controls.MethodsThirty-seven female AIS patients that underwent preoperative supine low-dose computed tomography imaging of the spine, hips and pelvis as part of their general workup were included and compared to 44 non-scoliotic age-matched female controls. A previously validated computerized method was used to measure the PI in 3D, as the angle between the line orthogonal to the inclination of the sacral endplate and the line connecting the center of the sacral endplate with the hip axis.ResultsThe PI was on average 46.8° ± 12.4° in AIS patients and 41.3° ± 11.4° in controls (p = 0.025), with a higher PI in Lenke type 5 curves (50.6° ± 16.2°) as compared to controls (p = 0.042), whereas the Lenke type 1 curves (45.9° ± 12.2°) did not differ from controls (p = 0.141).ConclusionLenke type 5 curves show a significantly higher PI than controls, whereas the Lenke type 1 curves did not differ from controls. This suggests a role of pelvic morphology and spino-pelvic alignment in the pathogenesis of idiopathic scoliosis. Further longitudinal studies should explore the exact role of the PI in the initiation and progression of different AIS types.
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20.
  • Charalampidis, Anastasios, et al. (författare)
  • Nighttime Bracing or Exercise in Moderate-Grade Adolescent Idiopathic Scoliosis
  • 2024
  • Ingår i: JAMA Network Open. - : AMER MEDICAL ASSOC. - 2574-3805. ; 7:1
  • Tidskriftsartikel (refereegranskat)abstract
    • IMPORTANCE Moderate-grade adolescent idiopathic scoliosis (AIS) may be treated with full-timebracing. For patients who reject full-time bracing, the effects of alternative, conservativeinterventions are unknown.OBJECTIVE To determine whether self-mediated physical activity combined with either nighttimebracing (NB) or scoliosis-specific exercise (SSE) is superior to a control of physical activity alone (PA)in preventing Cobb angle progression in moderate-grade AIS.DESIGN, SETTING, AND PARTICIPANTS The Conservative Treatment for Adolescent IdiopathicScoliosis (CONTRAIS) randomized clinical trial was conducted from January 10, 2013, throughOctober 23, 2018, in 6 public hospitals across Sweden. Male and female children and adolescentsaged 9 to 17 years with an AIS primary curve Cobb angle of 25° to 40°, apex T7 or caudal, and skeletalimmaturity based on estimated remaining growth of at least 1 year were included in the study. Datesof analysis were from October 25, 2021, to January 28, 2023.INTERVENTIONS Interventions included self-mediated physical activity in combination with eitherNB or SSE or PA (control). Patients with treatment failure were given the option to transition to afull-time brace until skeletal maturity.MAIN OUTCOMES AND MEASURES The primary outcome was curve progression of 6° or less(treatment success) or curve progression of more than 6° (treatment failure) seen on 2 consecutiveposteroanterior standing radiographs compared with the inclusion radiograph before skeletalmaturity. A secondary outcome of curve progression was the number of patients undergoing surgeryup until 2 years after the primary outcome.RESULTS The CONTRAIS study included 135 patients (45 in each of the 3 groups) with a mean (SD)age of 12.7 (1.4) years; 111 (82%) were female. Treatment success was seen in 34 of 45 patients (76%)in the NB group and in 24 of 45 patients (53%) in the PA group (odds ratio [OR], 2.7; 95% CI, 1.1-6.6).The number needed to treat to prevent curve progression with NB was 4.5 (95% CI, 2.4-33.5).Treatment success occurred in 26 of 45 patients (58%) in the SSE group (OR for SE vs PA, 1.2; 95% CI,0.5-2.8). Up to 2 years after the primary outcome time point, 9 patients in each of the 3 groupsunderwent surgery.CONCLUSIONS AND RELEVANCE In this randomized clinical trial, treatment with NB preventedcurve progression of more than 6° to a significantly higher extent than did PA, while SSE did not; inaddition, allowing transition to full-time bracing after treatment failure resulted in similar surgicalfrequencies independent of initial treatment. These results suggest that NB may be an effectivealternative intervention in patients rejecting full-time bracing.
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