How Do Spinopelvic Characteristics Change Post-Total Hip Arthroplasty? A Longitudinal Assessment Raising Awareness of the Postoperative Period.

BACKGROUND: Spinopelvic characteristics, including sacral slope (SS), are commonly evaluated in different positions pre-total hip arthroplasty (THA). This study aimed to: 1) investigate the change in spinopelvic parameters at 7 days (early) and 1-year post-THA; and 2) identify patient characteristics associated with a change in SS of more than 7° post-THA. METHODS: We prospectively studied 250 patients who underwent unilateral THA [132 women, age 66 years (range, 32 to 88)] and underwent biplanar images preoperatively and at 7 days and 1-year post-THA. Parameters measured included pelvic incidence, standing lumbar lordosis, SS, and proximal femoral angle (PFA). A SS change ≥ 7° was considered the threshold as it would result in more than a 5° change in cup orientation. RESULTS: Early post-THA SSstanding remained within ± 6º from preoperative measurements in 75% of patients, reduced by ≥ 7° in 9%, and increased by ≥ 7° in 16%. Those that showed a reduction in SS had the lowest PFA and the highest SS pre-THA (P = .028, .107, and < 0.001, respectively). From 7 days until the 1-year mark, pelvic tilt increased, SS reduced (mean: -4º, range: -29 to 17º, P < .001), and patients stood with greater hip extension ΔPFAstanding (mean 7°, range: -34 to 37°, P < .001). At 1 year, SSseated had remained within ± 6º, relative to the pre-THA value, in 49% of patients. CONCLUSIONS: Standing spinopelvic characteristics, especially SSstanding, remain within ±6° in three-quarters of patients both early- and at 1-year post-THA. In the remaining cases, pelvic tilt changes significantly. In 9% of cases, SS reduces ≥ 7° early THA, probably due to the alleviation of fixed-flexion contractures. The SSseated changes by ≥ ± 7° in almost 50% of cases in this study, and its clinical value as a preoperative planning tool should be questioned. LEVEL OF EVIDENCE: Level II, diagnostic study.

Simplified S1 Vertebral Bone Quality Score in the Assessment of Patients with Vertebral Fragility Fractures.

OBJECTIVE: To evaluate the effectiveness of the S1 vertebral bone quality (VBQ) score in assessing bone quality among patients with vertebral fragility fractures (VFF). Additionally, whether the combination of S1 VBQ and Hounsfield unit (HU) values improves the predictive accuracy of VFF. METHODS: Using lumbar noncontrast computed tomography and T1-weighted magnetic resonance imaging, we measured L1 HU values, S1 VBQ, and L1-L4 VBQ. To assess their predictive performance for VFF, we constructed receiver operating characteristic curves. We also compared the diagnostic efficacy of HU values with that of S1 VBQ and L1--L4 VBQ values for the joint diagnosis of VFF. The Delong test was used to compare the value of individual or combined predictions of VFF. RESULTS: In comparison to the nonfracture group, all patients exhibited markedly elevated S1 VBQ and L1--L4 VBQ and notably reduced HU values (P < 0.001). Multivariate analysis revealed that elevated S1 VBQ, increased L1--L4 VBQ, and decreased HU values independently correlated with VFF development. The areas under the curve for VFF prediction were 0.806 for S1 VBQ, 0.799 for L1--L4 VBQ, and 0.820 for HU values. According to the Delong test, the combination of HU values with S1 VBQ/L1--L4 VBQ significantly improved the diagnostic accuracy. CONCLUSIONS: The simplified S1 VBQ is a valuable tool for predicting the occurrence of VFF and can be used as an alternative to the L1--L4 VBQ. In addition, the combination of S1 VBQ and HU values can significantly improve the predictive value of VFF.

Reference values of lumbar spine range of motion by sex and age based on the assessment of supine trunk lateral bending-A preliminary study.

[Purpose] The purpose of this study was to clarify the preliminary reference values for the lumbar spine range of motion associated with lateral bending exercises by gender and age group. [Methods] Subjects were 82 volunteers without low back pain, including five males and five females in each age group from 16-19 to 80-89 years. All subjects underwent radiographs of the lumbar spine with lateral flexion; the range of lateral flexion of the vertebrae from T12 to the sacrum (ROLB) was measured twice by three observers. [Results] The ROLB of the entire T12-S1 of all subjects showed a significant negative correlation with age in both sexes (p < 0.01). The ROLB of the lumbar spine tended to be greater in females, with a statistically significant difference between those aged 16-19 and 70-79 (p < 0.05). Lateral flexion angles for each intervertebral segment were largest at L3-L4 and smallest at L5-S1 (0.7°). [Conclusion] Lumbar ROLB reference values were examined by gender and age group; ROLB was greatest in L3-L4, and ROLB tended to be lower in older age groups.

Assessment of sacral osseous fixation pathways for same-level dual transiliac-transsacral screw insertion.

INTRODUCTION: The purpose of this study is to (1) describe a pre-operative planning technique using non-reformatted CT images for insertion of multiple transiliac-transsacral (TI-TS) screws at a single sacral level, (2) define the parameters of a sacral osseous fixation pathway (OFP) that will allow for insertion of two TI-TS screws at a single level, and (3) identify the incidence of sacral OFPs large enough for dual-screw insertion in a representative patient population. METHODS: Retrospective review at a level-1 academic trauma center of a cohort of patients with unstable pelvic injuries treated with two TI-TS screws in the same sacral OFP, and a control cohort of patients without pelvic injuries who had CT scans for other reasons. RESULTS: Thirty-nine patients had two TI-TS screws at S1. Eleven patients, all with dysmorphic osteology, had two TI-TS screws at S2. The average pathway size in the sagittal plane at the level the screws were placed was 17.2 mm in S1 vs 14.4 mm in S2 (p = 0.02). Twenty-one patients (42%) had screws that were intraosseous and 29 (58%) had part of a screw that was juxtaforaminal. No screws were extraosseous. The average OFP size of intraosseous screws was 18.1 mm vs. 15.5 mm for juxtaforaminal screws (p = 0.02). Fourteen millimeters was used as a guide for the lower limit of the OFP for safe dual-screw fixation. Overall, 30% of S1 or S2 pathways were ≥ 14 mm in the control group, with 58% of control patients having at least one of the S1 or S2 pathways ≥ 14 mm. CONCLUSIONS: OFPs ≥ 7.5 mm in the axial plane and 14 mm in the sagittal plane on non-reformatted CT images are large enough for dual-screw fixation at a single sacral level. Overall, 30% of S1 and S2 pathways were ≥ 14 mm and 58% of control patients had an available OFP in at least one sacral level.

In vivo quantification of 3D displacement in sacral soft tissues under compression: Relevance of 2D US-based measurements for pressure ulcer risk assessment.

OBJECTIVE: 2D Ultrasound (US) imaging has been recently investigated as a more accessible alternative to 3D Magnetic Resonance Imaging (MRI) for the estimation of soft issue motion under external mechanical loading. In the context of pressure ulcer prevention, the aim of this pilot MRI study was to design an experiment to characterize the sacral soft tissue motion under a controlled mechanical loading. Such an experiment targeted the estimation of the discrepancy between tissue motion assessed using a 2D imaging modality (echography) versus tissue motion assessed using a (reference) 3D imaging modality (MRI). METHODS: One healthy male volunteer participated in the study. An MRI-compatible custom-made setup was designed and used to load the top region of the sacrum with a 3D-printed copy of the US transducer. Five MR images were collected, one in the unloaded and four in the different loaded configurations (400-1200 [g]). Then, a 3D displacement field for each loading configuration was extracted based on the results of digital volume correlation. Tissue motion was separated into the X, Y, Z directions of the MRI coordinate system and the ratios between the out-of-plane and in-plane components were assessed for each voxel of the selected region of interest. RESULTS: Ratios between the out-of-plane and in-plane displacement components were higher than 0.6 for more than half of the voxels in the region of interest for all load cases and higher than 1 for at least quarter of the voxels when loads of 400-800 [g] were used. CONCLUSION: The out-of-ultrasound-plane tissue displacement was not negligible, therefore 2D US imaging should be used with caution for the evaluation of the tissue motion in the sacrum region. The 3D US modality should be further investigated for this application.

Assessment of the acetabular version in relation to sagittal sacropelvic parameters.

The relationship between acetabular orientation and the sacropelvic parameters is of interest to both hip and spine surgeons as it is increasingly clear disease in one area can affect the other, including the outcome of surgical procedures. The aim of this study was to further clarify the relationship between measures of acetabular orientation and sacropelvic parameters. This study utilized a trauma CT database. A total of 100 scans on adult patients without overt hip or spinal disease were included. Measures of acetabular orientation included the acetabular sagittal angle (ASA) which uses the anterior pelvic plane as a reference and sacroacetabular angle which uses the sacral endplate as a reference (SA); spinopelvic parameters include the pelvic incidence (PI), sacral anatomic orientation (SAO) and pelvic thickness (PTH). Mean age 48.2 years (SD 18.0), 62% male. Mean values were: PI 50.5, SAO 50.7, PTH 106.4 mm, ASA-right 62.1, ASA-left 64.0, SA-right 67.2, and SA-left 65.4. There was substantial correlation between PI and SA (r = 0.628-0.630) and also between SAO and SA (-0.657 to -0.692). Liner regression determined SA was best predicted by the model: SA = 81 × SAO + 0.36 × PI. When using the anterior pelvic plane as a reference to define acetabular orientation, there does not appear to be any significant relationship between the sagittal orientation of the acetabulum and sacropelvic parameters. Using the sacrum as a common point of reference allows some further understanding of the interplay between pelvic parameters and the orientation of the acetabulum.

Fetal Sacral Ratio: A Novel Method for Prenatal Sonographic Assessment of Sacral Abnormalities.

OBJECTIVES: The sacral ratio (SR) was described as a postnatal X-ray-based method to detect sacral abnormalities and predict functional prognosis for fecal continence in children with anorectal malformations (ARMs). The present study aimed to describe a novel method of assessing sonographic fetal sacral ratio (f-SR) in a normal population of fetuses. METHODS: Sixty three-dimensional (3D) ultrasound reconstruction images of the sacrum obtained from routine low-risk scans performed between 21 and 26 weeks of gestation served for measurement. The f-SR was calculated in a coronal view as the ratio between lines drawn at the upper and lower levels of the iliac bone and the 5th sacral vertebra. Bland-Altman plots assessed the inter- and intrareader variabilities of measurements. RESULTS: The f-SR in the normal population of fetuses was 0.913 (±0.094). During the study period, three cases with ARM were examined and had a mean f-SR of 0.55. There was good repeatability of measurements and between readers' agreement. CONCLUSIONS: The present study introduces a novel prenatal sonographic f-SR that can be reliably calculated on prenatal 3D ultrasound with good reliability and reproducibility. Future research will identify the clinical significance of f-SR abnormalities in ARM and their long-term impact on continence.

Radiological Assessment of Giant Cell Tumour of Bone in the Sacrum: From Diagnosis to Treatment Response Evaluation.

Giant cell tumour of bone (GCTB) typically occurs in young adults from 20-40 years old. Although the majority of lesions are located in the epi-metaphyses of the long bones, approximately one third of tumours are located in the axial skeleton, of which only 4% in the sacrum. Sacral tumours tend to be large at the time of presentation, and they present with aggressive features such as marked cortical destruction and an associated soft tissue component. The 2020 World Health Organisation classification of Soft Tissue and Bone Tumours describes GCTB as a neoplasm which is locally aggressive and rarely metastasizing. The tumour contains three different cell types: neoplastic mononuclear stromal cells, macrophages and osteoclast-like giant cells. Two tumour subtypes were defined: conventional GCTB and malignant GCTB. Only 1-4% of GCTB is malignant. In this review article, we will discuss imaging findings at the time of diagnosis to guide the musculoskeletal radiologist in reporting these tumours. In addition, imaging for response evaluation after various treatment options will be addressed, such as surgery, radiotherapy, embolization and denosumab. Specific findings will be presented per imaging modality and illustrated by cases from our tertiary sarcoma referral center. Common postoperative and post-radiotherapy findings in GCTB of the sacrum on MRI will be discussed.

Subchondral Bone Changes Following Sacroiliac Joint Arthrodesis - A Morpho-mechanical Assessment of Surgical Treatment of the Painful Joint.

BACKGROUND: Sacroiliac joint arthrodesis is an ultima ratio treatment option for sacroiliac joint dysfunction. Fusion drastically reduces sacroiliac joint movement providing long-lasting pain-relief associated with tension-relief to the innervated sacroiliac joint structures involved in force closure. OBJECTIVES: To display the bone mineralization distribution patterns of the subchondral bone plate in 3 distinct regions (superior, anterior, and inferior) of the sacral and iliac counterparts of the sacroiliac joint pre- and post-sacroiliac joint arthrodesis and compare patterns of sacroiliac joint dysfunction post-sacroiliac joint fusion with sacroiliac joint dysfunction pre- arthrodesis patterns and those from healthy controls. STUDY DESIGN: An observational study. SETTING: The research took place at the University of Basel, Switzerland, where the specific image analysis program (Analyze, v7.4, Biomedical Imaging Resources, Mayo Foundation, Rochester, NY, USA) was made available. METHODS: Mineralization densitograms of 18 sacroiliac joint dysfunction patients pre- and post-sacroiliac joint arthrodesis (>= 6, >= 12, and >= 24 months post-surgery) were obtained using computed tomography osteoabsorptiometry. For each patient, pre- vs. post-surgery statistical comparisons were undertaken, using the Hounsfield unit values derived from the subchondral mineralization of superior, anterior, and inferior regions on the iliac and sacral auricular surfaces. Post-operative values were also compared to those from a healthy control cohort (n = 39). RESULTS: In the pre-operative cohort at all 3 follow-up times, the superior iliac region showed significantly higher Hounsfield unit values than the corresponding sacral region (P < 0.01). Mineralization comparisons were similar for the sacrum and ilium in the anterior and inferior regions at all follow-up points (P > 0.5) with no surgery-related changes. Sacral density increased significantly in the post-operative state; not observed on the ilium. Post-operative sacroiliac joints showed a significantly increased mineralization in the superior sacrum after >= 6 months (P < 0.05), not replicated after >= 12 nor >= 24 months. Further comparison of post-operative scans versus healthy controls revealed significantly increased mineralization in the superior sacral region at (>=) 6, 12, and 24 months (P < 0.01), likely related to bone grafting, and in the anterior and inferior regions in post-operative scans at >= 12 and >= 24 months follow-up (P < 0.05). LIMITATIONS: The given study is limited in sample size. Post-operative computed tomography scans had screws which may have left artifacts or partial volume effects on the surfaces. Healthy controls were different patients to the sacroiliac joint dysfunction and post-operative cohorts. Both cohorts were age-matched but this comparison did not take into account potential population differences. Size differences in the regions may have also been an influencing factor of the results as the regions were based on the size and shape of the articular surface. CONCLUSIONS: Sacroiliac joint arthrodesis results in an increased morpho-mechanical conformity in the anterior and inferior sacrum and reflects variable morpho-mechanical density patterns compared to the healthy state due to permanent alterations in the kinematics of the posterior pelvis.

An independent inter- and intraobserver agreement assessment of the AOSpine sacral fracture classification system.

BACKGROUND CONTEXT: The AOSpine sacral classification scheme was recently described. It demonstrated substantial interobserver and excellent intraobserver agreement in the study describing it; however, an independent assessment has not been performed. PURPOSE: To perform an independent inter- and intraobserver agreement evaluation of the AOSpine sacral fracture classification system. STUDY DESIGN: Agreement study. METHODS: Complete computerized tomography (CT) scans, including axial images, with coronal and sagittal reconstructions of 80 patients with sacral fractures were selected and classified using the morphologic grading of the AOSpine sacral classification system by six evaluators (from three different countries). Neurological modifiers and case-specific modifiers were not assessed. After a four-week interval, the 80 cases were presented to the same raters in a random sequence for repeat assessment. We used the Kappa coefficient (κ) to establish the inter- and intraobserver agreement. RESULTS: The interobserver agreement was substantial when considering the fracture severity types (A, B, or C), with κ=0.68 (0.63-0.72), but moderate when considering the subtypes: κ=0.52 (0.49-0.54). The intraobserver agreement was substantial considering the fracture types, with κ=0.69 (0.63-0.75), and considering subtypes, κ=0.61 (0.56-0.67). CONCLUSION: The sacral classification system allows adequate interobserver agreement at the type level, but only moderate at the subtypes level. Future prospective studies should evaluate whether this classification system allows surgeons to decide the best treatment and to establish prognosis in patients with sacral fractures.

Global incidence of spinal perineural Tarlov's cysts and their morphological characteristics: a meta-analysis of 13,266 subjects.

BACKGROUND: Spinal perineural Tarlov's cysts (TCs) are considered incidental findings that occasionally might exert pressure upon nerve roots and correspond with patients' signs and symptoms. Purpose of this meta-analysis is to deliver global incidence and characteristics (location, size, and shape) of TCs. METHODS: Following PRISMA checklist, all major databases were searched by two authors for radiologic studies reporting incidence and morphologic features (location, size, and shape) of TCs. Anatomical Quality Assessment tool was applied for risk of bias evaluation. Meta-analysis of random-effects model was employed. Subgroup analysis for regional distribution, gender, sacral levels, age, correspondence with symptoms, and persistent genital arousal disorder (PGAD) were planned ahead. RESULTS: 22 radiologic studies of level 3 evidence involving 13,266 subjects were included. Global pooled prevalence of TCs was 4.18% (95% CI 2.47-6.30). Mean pooled sagittal diameter was 11.86 mm (95% CI 10.78-12.93). Sacral cysts strongly prevailed over the other segments. Of the sacral, S2 level was the most common (46.7% [95% CI 29.4-60.5]). Geographically, the highest incidence was found in Europe (6.07% [95% CI 1.49-13.00]), followed by North America (3.82% [95% CI 0.49-9.44]), and Asia (3.33% [95% CI 1.52-5.75]). TCs were more common in women than in men (5.84% vs 3.03%, p < 0.001, test of homogeneity, χ2). Subjects with PGAD had incidence of 37.87% (95% CI 2.45-81.75). TCs in pediatric population are rare-0.53% (95% CI 0.02-1.51). 15.59% of TCs corresponded with symptoms. CONCLUSIONS: Spinal perineural (Tarlov) cysts are found in a minority of population. S2 level of the sacral bone is affected most frequently. There is female predominance. Correspondence with symptoms is seen in less than one-fifth of TCs. Studies with stronger evidence level are needed to corroborate the results. The purported high incidence in PGAD requires confirmation in case-control studies for the risk-ratio calculation.

Assessment of sacral ratio in patients with anorectal malformations: Can magnetic resonance imaging replace conventional radiograph?

INTRODUCTION: In patients with anorectal malformations (ARM), the sacral ratio (SR) serves as an established predictive marker for functional prognosis and is derived from conventional radiographs. More recently, magnetic resonance imaging (MRI) has emerged as a diagnostic alternative for preoperative/baseline assessment of patients with ARM. With this study we aimed to evaluate if the SR could be reliable be measured from MRI images and if it correlated to SR measurements obtained from radiographs. METHODS: Two raters analyzed MRI data and conventional radiographs from thirty-one subjects (n = 17 with ARM; n = 14 controls). We calculated intra-class correlation coefficients (ICCs) to test inter-rater reliability and applied paired t-tests to examine if SR parameters from MRI were comparable with those from pelvic radiograph. We further computed Pearson's correlation coefficients to test the linear relationship between SR calculated from MRI and conventional radiographs. RESULTS: The ARM and control groups did not statistically differ in their age and weight on the day of the MRI scan. Reliability analysis revealed an excellent inter-rater agreement for SR from radiograph parameters with an intraclass correlation coefficient (ICC) of 0.94, respectively of 0.86 for MRI (frontal plane), and of 0.84 for MRI (sagittal plane). The correlation coefficient between SR calculated from the sagittal MRI and SR calculated from radiograph images was significant and high (r = 0.80, P < 0.001). The SRs from MRI images did not significantly differ from SRs from radiographs, but were also not statistically equivalent. CONCLUSION: Our results demonstrate that the SR can be derived from MRI images with good inter-rater reliability. The SR value is marginal higher when calculated on MRI, presumably due to inclusion of cartilaginous yet unossified structures.

Spinopelvic Dissociation: Assessment, Reduction Strategies, and Fixation Techniques.

Spinopelvic dissociation is a rare injury associated with 2% to 3% of transverse sacral fractures and 3% of sacral fractures associated with pelvic ring injuries. When spinopelvic dissociation is expediently identified and treated appropriately, patient outcomes can be maximized, highlighting the importance of early diagnosis and treatment. Because of its rarity and complexity, there remains a paucity of high-level evidence-based guidance on treating this complex issue. No consensus exists on fixation techniques or reduction maneuvers to achieve stability, allowing for early functional rehabilitation. The purpose of this article is to review the current body of literature to better understand this injury pattern to help establish a treatment algorithm that appropriately guides the treating surgeons in the surgical planning and perioperative care of these patients.

Assessment of osseous corridor for transiliac-transsacral screws and clinical applications: Computational simulation study.

BACKGROUND: Transiliac-transsacral (TITS) screw fixation might be necessary in some cases involving the vertical shearing injuries with transforaminal fracture and bilateral posterior ring injuries. However, the possibility of S1 TITS screw should be preoperatively assessed because the pelvic ring injuries with sacral dysmorphism had the insufficient osseous corridors. HYPOTHESIS: AxWS2 may predict the possibility of TITS screw fixation and be used as the new indicator to discriminate the sacral dysmorphism. MATERIALS & METHODS: The conventional CT images of eighty-two cadaveric pelvis imported into Mimics® software to reconstruct three-dimensional (3D) models. A 7.0 mm-sized screw was processed into a 3D model using a 3D-sensor at actual size and virtually implanted as S1 and S2 TITS screw using Mimics® software. The cortical violation around screw path was evaluated using 3D biplanar and conventional CT images. The osseous corridor widths around TITS screws were measured in the axial plane images and defined as AxWS1 and AxWS2, respectively. RESULTS: Despite no cortical violation in S2 of all models, cortical violation of S1 TITS screw was found in 20 models. Of them, 14 models (impossible models) were identified in the 3D biplanar images, and all 20 models (CT-violation models) were identified only in CT axial plane images. AxWS1 was<7mm in the impossible models and<9.0mm in the CT-violation models. AxWS2 negatively correlated with AxWS1 (R -0.450, p<0.01). By receiver operating characteristic curve analysis to identify the CT-violation model using AxWS2, the cut-off value of AxWS2 was 13.32mm (sensitivity 0.70, specificity 0.70). DISCUSSION: By using AxWS2, the possibility of S1 TITS screw fixation could be predicted and safely placed without cortical violation, if AxWS2 was less than 13mm. Considering the negative relationship with AxWS1, AxWS2 should be used as a new indicator to predict safe S1 TITS screw fixation. LEVEL OF EVIDENCE: III, controlled laboratory study.

Ultrasonographic and clinical assessment of peripheral enthesitis and arthritis in an Italian cohort of inflammatory bowel disease patients.

AIMS: To evaluate the prevalence of clinical and ultrasonographic musculoskeletal involvement in Italian patients with inflammatory bowel disease (IBD). METHODS: In this cross-sectional multicenter study, 148 consecutive patients with IBD were evaluated by a gastroenterologist and a rheumatologist. All patients underwent a B-mode and power Doppler ultrasonographic examination of 6 pairs of entheses and of knee and ankle joints. RESULTS: A positive history for at least one musculoskeletal manifestation was reported by 40.5% of patients, more frequently in ulcerative colitis (UC) (p = 0.033). Inflammatory back pain was reported by 13.5% of patients, and a past history of peripheral arthritis by 14.9%, entheseal inflammation by 14.2% and dactylitis by 2.7%. At clinical examination, arthritis was observed in 19.6% of patients and enthesitis in 33%. Oligoarthritis and enthesitis at clinical examination were more frequently observed in UC than in Crohn disease (CD). 37.8% of total IBD patients fulfilled ASAS classification criteria for axial and/or peripheral spondyloarthritis, 8.1% ASAS classification criteria for axial spondyloarthritis, and 29.7% ASAS classification criteria for peripheral spondyloarthritis. With ultrasonographic examination, signs of entheseal involvement were observed in 87.8% of patients, while at power Doppler, ≥1 abnormality was observed in 27.1%. ASAS+ patients compared to those ASAS- had a significantly higher frequency at ultrasonography of acute entheseal abnormalities, power Doppler entheseal positivity and joint involvement. These abnormalities at ultrasonography were also observed in 34%, 13% and 12% of ASAS- patients. CONCLUSIONS: Musculoskeletal manifestations occur frequently in patients with IBD. Ultrasonographic entheseal and joint involvement were also observed in asymptomatic patients.

Assessment of Sagittal Spinopelvic Balance in a Population of Normal Chinese Children.

STUDY DESIGN: A retrospective study of 257 normal children at a single center from July 2016 to November 2018 was performed. OBJECTIVE: To evaluate the spinopelvic parameters in a population of normal children and adolescents in mainland China. SUMMARY OF BACKGROUND DATA: Values for sagittal parameters of the spine vary significantly by ages and different population. No study has yet quantified the normal measures for children and adolescents in China, or how these measures compare with other populations. METHODS: Pelvic incidence (PI), sacral slope, pelvic tilt, thoracic kyphosis (TK, T5-T12), lumbar lordosis (LL, L1-S1), and sagittal vertical axis were measured and evaluated by whole spine AP&lateral X-ray images. RESULTS: A total of 257 subjects, including 116 boys (45%) and 141 girls (55%) aged 3 to 12 years, were enrolled. Correlation matrix analysis demonstrated that sagittal balance is strongly correlated with age and Risser sign, including PI, a reported fixed parameter. Further investigation showed that PI could be expressed by the equation PI = 26.243+1.153×age. CONCLUSION: PI was not a fixed but a dynamic parameter in the population under 12-year old. Indeed, PI increases with age and bone maturity in childhood. We also found lower PI, pelvic tilt, and sacral slope compared with published studies of adolescents in other countries. These results may aid in the treatment of patients with spinal deformity, to help them achieve a certain degree of sagittal spinopelvic balance. LEVEL OF EVIDENCE: 2.

Clinical Improvement and Cost-effectiveness of CT-guided Radiofrequency Sacroplasty (RFS) and Cement Sacroplasty (CSP) - a Prospective Randomised Comparison of Methods. / Klinische Verbesserung und Wirtschaftlichkeit nach CT-gesteuerter Radiofrequenzsakroplastie und Zementsakroplastie ­ ein prospektiver randomisierter Methodenvergleich.

INTRODUCTION: The objective of this study was a comparative analysis of cement augmentation by means of RFS and CSP with regard to outcome and cost-effectiveness. PATIENTS AND METHODS: CT-guided cement augmentation was performed on 100 patients with a total of 168 non-dislocated insufficiency fractures, 50 patients being treated with RFS and 50 patients with CSP. Leakages were detected by CT. Pain intensity was determined on a VAS before and after the intervention. The patients' self-sufficiency was assessed using the Barthel index. Patients were asked about any complications and their level of satisfaction. Costs incurred for carrying out the procedure were compared with the respective reimbursements received. RESULTS: Both procedures were technically fully feasible. No leakages were found in the RFS group, as opposed to 8.1% asymptomatic leakages in the CSP group. The mean value for pain before intervention was 8.8 in the RFS group and 8.7 in the CSP group. On the second postoperative day, there was a significant pain reduction with a value of 2.4 for both groups, which remained more or less constant over the follow-up period. The Barthel index increased significantly from an average of 30 before the intervention to 80 on the fourth postoperative day and 70 after 24 months. No differences were found between the two procedures with regard to pain, improvement in functional status and satisfaction. Taking into account the state-wide base rate used for calculating reimbursement, 3,834.75 € remained for RFS and 5,084.32 € for CSP. CONCLUSION: RFS and CSP are minimally invasive procedures that achieve equally good and sustained pain reduction, leading to markedly improved self-sufficiency of the patients. With regard to possible cement leakages, RFS is the safer method. A profit can be generated with both techniques.

Cost Analysis of Magnet-driven Growing Rods for Early-onset Scoliosis at 5 Years.

STUDY DESIGN: Prospective case series of nine children with early-onset scoliosis (EOS) treated by a single surgeon with a novel implant, the magnet-driven growing rod (MdGR) in a publicly funded health care service accounting for "payer costs" (PC) incurred. OBJECTIVE: The aim of this study was to compare the cost-effectiveness of MdGR versus conventional growing rods (CGRs) with respect to the PC incurred for treating EOS at 5 years. SUMMARY OF BACKGROUND DATA: Cost estimate and mathematical modeling study projections of MdGR have shown despite high insertional costs, it breaks even with CGR by 3 to 4 years. However, no clinical study to date exists either supporting or refuting this hypothesis. METHODS: Nine patients with EOS secondary to idiopathic (two), congenital (one), syndromic (three), and neuromuscular (three) etiologies treated by submuscular insertion of MdGR against stringent inclusion criteria formed the study cohort. We collected costs incurred with all aspects of care over the lifetime of device (or at least 5 years) from payers' perspective to compute and report average PC incurred per patient. We performed this cost analysis by comparing the MdGR PC against literature reported PC for CGR at 5 years. RESULTS: There were five single rod (SR) and two dual rod (DR) de novo MdGR insertions, while two patients had conversion of CGR to MdGR. MdGR alone accounted for at least 50% of overall budget. The MdGR was at least 40% more cost-effective in comparison to the CGR (£34,741 vs. £52,293) and there were seven MdGR graduates. CONCLUSION: The first study reporting direct PC incurred in EOS treated by MdGR that is devoid of any mathematical modeling and deterministic sensitivity analysis is presented. The true societal/human cost savings taking into consideration indirect costs are likely to be significantly higher. MdGR is a promising novel implant that may eventually become the "standard of care" for certain EOS etiologies. LEVEL OF EVIDENCE: 4.

Is L5-S1 motion segment different from the rest? A radiographic kinematic assessment of 72 patients with chronic low back pain.

PURPOSE: The relationship between biomechanical instability and degenerative changes in the lumbar spine in chronic low back pain (CLBP) patients remains controversial. The main objective of this retrospective radiographical study was to evaluate changes in kinematics at different lumbar levels (in particular the L5-S1 level) with progressive grades of disc degeneration and facet joint osteoarthritis in CLBP patients. METHODS: Using standing neutral and dynamic flexion/extension (Fx/Ex) radiographs of the lumbar spine, in vivo segmental kinematics at L1-L2 through L5-S1 were evaluated in 72 consecutive CLBP patients. Disc degeneration was quantified using changes in signal intensity and central disc height on mid-sagittal T2-weighted magnetic resonance (MR) scans. Additionally, the presence or absence of facet joint osteoarthritis was noted on T2-weighted axial MR scans. RESULTS: Disc degeneration and facet joint osteoarthritis occurred independent of each other at the L5-S1 level (p = 0.188), but an association was observed between the two at L4-L5 (p < 0.001) and L3-L4 (p < 0.05) levels. In the absence of facet joint osteoarthritis, the L5-S1 segment showed a greater range of motion (ROM) in Ex (3.3° ± 3.6°) and a smaller ROM in Fx (0.6° ± 4.2°) compared with the upper lumbar levels (p < 0.05), but the differences diminished in the presence of it. In the absence of facet joint osteoarthritis, no change in L5-S1 kinematics was observed with progressive disc degeneration, but in its presence, restabilisation of the L5-S1 segment was observed between mild and severe disc degeneration states. CONCLUSION: The L5-S1 motion segment exhibited unique degenerative and kinematic characteristics compared with the upper lumbar motion segments. Disc degeneration and facet joint osteoarthritis occurred independent of each other at the L5-S1 level, but not at the other lumbar levels. Severe disc degeneration in the presence of facet joint osteoarthritis biomechanically restabilised the L5-S1 motion segment.