The efficacy of bracing larger curves in adolescent idiopathic scoliosis (AIS) patients is uncertain. We aimed to assess the influence of night-time bracing in AIS patients with main curves exceeding ...40° Cobb angle at brace initiation.
We reviewed AIS patients treated with nighttime braces between 2005 and 2018. Patients with curves ≥ 25° and estimated growth potential were included. Patients were monitored with radiographs from brace initiation until brace weaning at skeletal maturity. Patients were grouped based on curve magnitude at initial evaluation: a control group (25-39°) and a large-curves group (≥ 40°). Progression was defined as > 5° increase.
We included 299 patients (control group, n = 125; large-curves group, n = 174). In the control group, 65 (52%) patients progressed compared with 101 (58%) in the large-curves group (P = 0.3). The lower-end vertebra (LEV) shifted distally post-bracing in 41 (23%) patients in the largecurves group. Patients with progressive large curves were younger (age 13.2 SD 1.5 vs. 13.9 SD 1.1, P = 0.009) and more premenarchal (n = 36 42% vs. n = 6 9%, P < 0.001) compared with non-progressive large curves.
Progression risk in patients with curves exceeding 40° treated with night-time bracing is similar to smaller curves. The LEV moved distally in almost one-fourth of the larger curves, possibly affecting fusion levels in cases of surgery.
Objective: The demand for spinal fusion is increasing, with concurrent reports of iatrogenic adult spinal deformity (flatback deformity) possibly due to inappropriate lordosis distribution. This ...distribution is assessed using the lordosis distribution index (LDI) which describes the upper and lower arc lordosis ratio. Maldistributed LDI has been associated to adjacent segment disease following interbody fusion, although correlation to later-stage deformity is yet to be assessed. We therefore aimed to investigate if hypolordotic lordosis maldistribution was associated to radiographic deformity-surrogates or revision surgery following instrumented lumbar fusion.Methods: All patients undergoing fusion surgery ( ≤ 4 vertebra) for degenerative lumbar diseases were retrospectively included at a single center. Patients were categorized according to their postoperative LDI as: “normal” (LDI 50–80), “hypolordotic” (LDI < 50), or “hyperlordotic” (LDI > 80).Results: We included 149 patients who were followed for 21 ± 14 months. Most attained a normally distributed lordosis (62%). The hypolordotic group had increased postoperative pelvic tilt (PT) (p < 0.001), pelvic incidence minus lumbar lordosis (PI–LL) mismatch (p < 0.001) and decreased global lordosis (p = 0.007) compared to the normal group. Survival analyses revealed a significant difference in revision surgery (p = 0.03), and subsequent multivariable logistic regression showed increased odds of 1-year revision in the hypolordotic group (p = 0.04). There was also a negative, linear correlation between preoperative pelvic incidence (PI) and postoperative LDI (p < 0.001).Conclusion: In patients undergoing instrumented lumbar fusion surgery, hypolordotic lordosis maldistribution (LDI < 50) was associated to increased risk of revision surgery, increased postoperative PT and PI–LL mismatch. Lordosis distribution should be considered prior to spinal fusion, especially in high PI patients.
Following surgical treatment for adult spinal deformity (ASD) there is an increased risk of revision surgery due to mechanical failure or pseudarthrosis. Demineralized cortical fibers (DCF) were ...introduced at our institution aiming to reduce the risk of pseudarthrosis after ASD surgery.
We wanted to investigate the effect of DCF on postoperative pseudarthrosis compared with allogenic bone graft in ASD surgery without three-column osteotomies (3CO).
All patients undergoing ASD surgery between January 1, 2010 to June 31, 2020 were included in this interventional study with historical controls. Patients with current or previous 3CO were excluded. Before February 1, 2017, patients undergoing surgery received auto- and allogenic bone graft (non-DCF group) whilst patients after received DCF in addition to autologous bone graft (DCF group). Patients were followed for at least two years. The primary outcome was radiographic or CT-verified postoperative pseudarthrosis requiring revision surgery.
We included 50 patients in the DCF group and 85 patients in the non-DCF group for final analysis. Pseudarthrosis requiring revision surgery at two-year follow-up occurred in seven (14%) patients in the DCF group compared with 28 (33%) patients in the non-DCF group (p = 0.016). The difference was statistically significant, corresponding to a relative risk of 0.43 (95%CI: 0.21–0.94) in favor of the DCF group.
We assessed the use of DCF in patients undergoing ASD surgery without 3CO. Our results suggest that the use of DCF was associated with a considerable decreased risk of postoperative pseudarthrosis requiring revision surgery.
•Pseudarthrosis is a major cause of revision surgery following surgical treatment of adult spinal deformity.•The use of bone grafts in spine surgery enhances fusion and lowers the rate of pseudarthrosis.•Demineralized cortical fibers were associated with a considerably lower pseudarthrosis risk than allogenic bone graft.
Purpose
Adolescent idiopathic scoliosis (AIS) is characterized by coronal scoliosis and often a sagittal hypokyphosis. The effect of bracing on the sagittal profile is not well understood. The aim of ...this study is to assess the effect of night-time bracing on the sagittal profile in patients with AIS.
Methods
We retrospectively included AIS patients with a main curve of 25–45° treated with a night-time brace in our institution between 2005 and 2018. Patients with estimated growth potential based on either Risser stage, hand X-rays, or menarchal status were included. Coronal and sagittal radiographic parameters were recorded at both brace- initiation and -termination. Patients were followed until surgery or one year after brace termination. Results were compared to a published cohort of full-time braced patients.
Results
One hundred forty-six patients were included. Maximum thoracic kyphosis (TK) increased 2.5° (± 9.7) (
p
= 0.003), corresponding to a 3.5-fold relative risk increase post bracing in TK compared to a full-time brace cohort. Twenty-seven percent (
n
= 36) of the patients were hypokyphotic (T4/T12 < 20°) at brace initiation compared with 19% (
n
= 26) at brace termination (
p
= 0.134). All other sagittal parameters remained the same at follow-up. We found no association between progression in the coronal plane and change in sagittal parameters.
Conclusion
This is the first study to indicate that night-time bracing of AIS does not induce hypokyphosis. We found a small increase in TK, with a substantially lower risk of developing flat back deformity compared to full-time bracing. The coronal curve progression was not coupled to a change in TK.
Purpose
Risser stage is widely used as a marker for skeletal maturity (SM) and thereby an indirect measure for the risk of progression of adolescent idiopathic scoliosis (AIS). The Scoliosis Research ...Society recommends bracing for Risser stages 0–2 as Risser stage 3 or above is considered low risk. Very few studies have assessed the risk of progression during bracing in Risser stages 3–4. The objective of the current study is to determine if Risser stages 3–4 provide a meaningful cutoff in terms of progression risk in patients with AIS treated with night-time bracing.
Methods
AIS patients treated with night-time brace from 2005 to 2018 with a Cobb angle between 25 and 40 degrees and Risser stages 0–4 were retrospectively included. Curve progression (> 5 degrees increase) was monitored until surgery or SM. Skeletal maturity was defined as either 2 years postmenarchal, no height development or closed ulnar epiphyseal plates on radiographs.
Results
One hundred and thirty-five patients were included (Risser stages 0–2:
n
= 86 and 3–4:
n
= 49). Overall, radiographic curve progression occurred in 52% while progression beyond 45 degrees was seen in 35%. The progression rate in the Risser 0–2 group was 60% and 37% in the Risser 3–4 group (
p
= 0.012). In multivariate logistic regression analysis, adjusted for Risser stages and age, only premenarchal status showed a statistically significant association with progression (OR: 2.68, 95%CI 1.08–6.67).
Conclusion
Risser stage does not provide a clinically meaningful differentiation of progression risk in AIS patients treated with a night-time brace. Risk assessment should include other more reliable measures of skeletal growth potential.
To determine the rate of postoperative complications following surgery for Scheuermann?s kyphosis (SK) and ascertain whether restoration to an ideal Roussouly spine type reduced the incidence of ...postoperative proximal junctional kyphosis (PJK).
We retrospectively screened all patients undergoing SK surgery at our institution (2010?2017) and excluded patients with less than two years of follow-up. Postoperative complications were identified as early or late and minor or major. Successful restoration of Roussouly spine type was assessed and patients were classified as ?restored? or ?non-restored.? Associations between ideal Roussouly restoration and postoperative PJK were evaluated using logistic regression analysis.
The study included 22 patients with a median age of 23 (IQR, 20.0?43.8) years. Postoperative complications developed in 17 (77%) of these cases. All 17 patients developed minor complications; seven (32%) patients also exhibited major complications. PJK was diagnosed in 55% of the patients with an 18% overall two-year revision rate. Forty-four percent of the patients in the restored group developed PJK compared to 83% in the non-restored group (p=0.162). Multivariable logistic regression analysis revealed a trend towards an increased incidence of PJK in the non-restored group, albeit without statistical significance (OR, 9.4; 95% CI, 0.7?122.5, p=0.087).
Our study revealed that 77% of patients undergoing surgery for SK developed at least one complication with a two-year revision rate of 18%. PJK was detected less frequently in patients who were restored to their ideal Roussouly spine type, although this finding did not achieve statistical significance.
Strategies for biomarker discovery increasingly focus on biofluid protein and peptide expression patterns. Post-translational modifications contribute significantly to the pattern complexity and ...thereby increase the likelihood of obtaining specific biomarkers for diagnostics and disease monitoring. Glycosylation is a common post-translational modification that plays a role e.g. in cell adhesion and in cell-cell and receptor-ligand interactions. Abnormal protein glycosylation has important disease associations, and the glycoproteome is therefore a target for biomarker discovery. Here we present a simple and highly selective strategy for purification of sialic acid-containing glycopeptides (the sialiome) from complex peptide mixtures. The approach utilizes a high and selective affinity of sialic acids for titanium dioxide under specific buffer conditions. In combination with mass spectrometry we used this strategy to characterize the human plasma and saliva sialiomes where 192 and 97 glycosylation sites, respectively, were identified. Furthermore we illustrate the potential of this method in biomarker discovery.
Biomarkers in the cerebrospinal fluid (CSF) may be important for the diagnosis of chronic degenerative disorders in the central nervous system including dementia. Existing CSF biomarkers for ...dementia, however, are relatively nonspecific. More specific markers may be found by targeting investigations based on knowledge of the molecular pathology of the disease in question. In Alzheimer’s disease, hyperphosphorylation of the tau protein is a characteristic feature and thus a comprehensive characterization of the phosphoproteome of the CSF may be pursued to obtain a complete picture of phosphorylation aberrations in health and disease. Toward that goal we here describe a method for a comprehensive isolation and identification of phosphorylated tryptic peptides derived from CSF proteins using a simple sample preparation step and titanium dioxide-affinity chromatography followed by MALDI-TOF or LC-MS/MS linear iontrap-FT mass spectrometry. Whereas not all previously reported phosphoproteins were found in normal CSF, we detected 56 putative novel phosphorylation sites in 38 proteins in addition to known sites. The approach seems to be a promising foundation for the discovery of new biomarkers embedded in the CSF phosphoproteome.
Definition of QoE Fairness in Shared Systems Hossfeld, Tobias; Skorin-Kapov, Lea; Heegaard, Poul E. ...
IEEE communications letters,
2017-Jan., 2017-1-00, Letnik:
21, Številka:
1
Journal Article
Recenzirano
Odprti dostop
User-centric service and application management focuses on the quality of experience (QoE) as perceived by the end user. Thereby, the goal is to maximize QoE while ensuring fairness among users, ...e.g., for resource allocation and scheduling in shared systems. Although the literature suggests to consider consequently QoE fairness, there is currently no accepted definition of QoE fairness. The contribution of this letter is the definition of a generic QoE fairness index F, which has desirable key properties as well as the rationale behind it. By using examples and a measurement study involving multiple users downloading web content over a bottleneck link, we differentiate the proposed index from QoS fairness and the widely used Jain's fairness index. Based on results, we argue that neither QoS fairness nor Jain's fairness index meet all of the desirable QoE-relevant Properties, which are met by F. Consequently, the proposed index F may be used to compare QoE fairness across systems and applications, thus serving as a benchmark for QoE management mechanisms and system optimization.
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