Jason Cheung

The Cobb angle (CA) serves as the principal method for assessing spinal deformity, but manual measurements of the CA are time-consuming and susceptible to inter- and intra-observer variability. While learning-based methods, such as SpineHRNet+, have demonstrated potential in automating CA measurement, their accuracy can be influenced by the severity of spinal deformity, image quality, relative position of rib and vertebrae, etc. Our aim is to create a reliable learning-based approach that provides consistent and highly accurate measurements of the CA from posteroanterior (PA) X-rays, surpassing the state-of-the-art method. To accomplish this, we introduce SpineHRformer, which identifies anatomical landmarks, including the vertices of endplates from the 7th cervical vertebra (C7) to the 5th lumbar vertebra (L5) and the end vertebrae with different output heads, enabling the calculation of CAs. Within our SpineHRformer, a backbone HRNet first extracts multi-scale features from the inp...

Study Design. Prospective study. Objective. To compare the burden between chronic nonspecific low back pain (LBP) and axial spondyloarthropathy (SpA). Summary of Background Data. Chronic nonspecific LBP and SpA are two debilitating yet different chronic musculoskeletal disorders. To compare their burden, propensity score matching is used to control for potential confounders and match the study subjects. Materials and Methods. Two prospectively collected cohorts of LBP (n=269) and SpA (n=218) patients were studied. Outcomes included current LBP, 36-item Short Form Questionnaire, Oswestry Disability Index, EuroQol 5-dimension 5-level Questionnaire, and EuroQol Visual Analog Scale. With the inherent differences between the two types of patients, propensity score matching was performed for comparing the two groups. Baseline covariates of age, sex, education level, occupation, smoking, and drinking history were selected for the estimation of propensity scores for each subject with the logistic regression model. Significant independent variables for the outcome of current back pain were included in the multivariate logistic regressions. Results. A total of 127 matched pairs were identified, with 254 patients. In the matched cohort, more patients with chronic LBP had current back pain (95.3%) as compared with SpA (71.7%). Patients with SpA were younger (P<0.001), with more males (P<0.001), and better educated (P=0.001). There was less current back pain and higher nonsteroidal anti-inflammatory drug use (P<0.001). Most SpA patients had lower Oswestry Disability Index than LBP patients and with low disease activity. Patients with LBP had worse outcome scores as compared with SpA patients given the same Visual Analog Scale. LBP patients had 8.6 times the odds (95% CI: 3.341–20.671; P<0.001) of experiencing current back pain compared with SpA patients. Conclusions. The disease activity of SpA patients is well controlled. However, patients with chronic LBP have worse pain severity, disability, and health-related quality of life. This has implications on resource utilization and the necessity of advancing LBP understanding and management. Level of Evidence. Type I prognostic study.

This cross-sectional study aims to investigate the relationship between the simplified olecranon, simplified digital, and distal radius and ulna (DRU) classifications, and whether they can aid in more comprehensive maturity assessment together. Left hand and wrist and lateral elbow radiographs from pediatric patients were assessed using the three skeletal maturity indices. The association between maturity indices was investigated using Goodman and Kruskal’s gamma, and by mapping of individual grades based on chronological age. Specific maturity grades, at which peak height velocity (PHV) occurs as previously identified, were based upon to explore how the three systems interact. A total of 114 patients (63.2% girls) were studied. Correlations and associations between the three maturity parameters were significant (all at P < 0.001). Mapping revealed uneven spans and coverage of different periods by each index. Olecranon stage 1 coincided with R3 (for girls), R4 (for boys), U3, and SS1. Olecranon stage 5 occurred as early as R7, U6, and SS4. Upon elbow fusion, the simplified digital (SS5–SS8) and DRU (R8–R11 and U7–U9) classifications can be used for assessment until maturity. The inter-relationship of the simplified hand, wrist, and olecranon methods indicates their combined use. DRU grades can be used in growth periods which are less well covered. Prepubertal and growth acceleration phase of pubertal growth spurt can best be assessed by both the simplified olecranon (stages 1–3) and DRU classifications (R1–R5 and U1–U4). All three indices are required during PHV. For post-PHV, DRU (R8–R11 and U7–U9) and simplified digital method (SS5–SS8) complement each other for assessment until skeletal maturity.

Study Design. Prospective observational study. Objective. To determine the prevalence of isolated thoracic degeneration on magnetic resonance imaging (MRI), demographic factors and imaging features, as well as the patient-reported quality of life outcomes associated with this condition. Summary of Background Data. Thoracic intervertebral discs are least susceptible to disc degeneration (DD) and may represent a manifestation of “dysgeneration.” These discs may never be hydrated from the beginning and seem hypointense on MRI. Patients and Methods. A population-based MRI study of 2007 volunteers was conducted. Each disc from C2/3 to L5/S1 was measured by Pfirrmann and Schneiderman grading. Disc herniation, Schmorl node (SN), high-intensity zones (HIZ), and Modic changes were studied. DD was defined by Pfirrmann 4 or 5. patient-reported quality of life scores, including a 36-item short-form questionnaire and visual analog scale for low back pain, were recorded. Subjects were divided into “isolated thoracic degeneration” (only thoracic segment) and “tandem thoracic degeneration” (thoracic with other segments). The association between imaging findings and isolated thoracic degeneration was determined using multivariate logistic regression. Results. The mean age of the subjects was 50.0 ± 0.5 and 61.4% were females (n = 1232). Isolated thoracic degeneration was identified in 2.3% of the cohort. Factors associated with isolated thoracic degeneration included lower age, C6/7 HIZ, T8/9 HIZ, and T8/9 SN. Factors associated with tandem thoracic degeneration included L4/5 posterior bulging. The thoracic and lumbar tandem degeneration group demonstrated higher bodily pain, despite a lower visual analog scale, and a higher physical component score of the 36-item short form. Conclusions. Isolated thoracic degeneration demonstrated an earlier age of onset, mostly involving the mid-thoracic region (T5/6–T8/9), and in association with findings such as SN. Subjects with tandem thoracolumbar degeneration had less severe lumbar DD and low back pain as compared with those with isolated lumbar degeneration. This paints the picture of “dysgeneration” occurring in the thoracic and lumbar spine. Level of Evidence. 1.

Areal and volumetric BMD (aBMD and vBMD) measured by DXA and quantitative CT (QCT), respectively, are usually employed to predict vertebral fracture risks. In this study, we induced compression and wedge vertebral fractures to test if the types of fracture could influence the selection of bone mineral measures to predict biomechanical properties of vertebral bodies. DXA and QCT were employed to scan twenty-four male cadaveric vertebral bodies of humans for bone mineral content (BMC) and aBMD measures, and vBMD measures, respectively. We computed vBMD measures from three kinds of volumes of interest: intact structures (vertebral body, cortical compartment, and trabecular core), axially middle sections (1.250-1.875 cm height) of the intact structures, and clinically used elliptical regions of trabecular bone. We loaded vertebral bodies to failure for properties of strength (Pu), failure displacement (δu), and stiffness (K). Thirteen vertebral bodies sustained compression fractures and the remaining sustained wedge fractures. Linear and power regression models were used to test bone mineral predictions for Pu, δu, and K. We also did equality tests of correlation coefficients. Our results showed aBMD, BMC, and vBMD of the middle section of trabecular bone had the strongest correlations with Pu (R2 = 0.6420, p < 0.001), δu (R2 = 0.4619, p < 0.001), and K (R2 = 0.5992, p < 0.001) in power regression models, respectively when compression and wedge fractures were mixed. Considering compression fractures only, vBMD of the intact vertebral body displayed the strongest correlations with both Pu (R2 = 0.6529, p < 0.001) and K (R2 = 0.6354, p < 0.001) while BMC showed the strongest correlation with δu (R2 = 0.4376, p < 0.001) in linear regression models. When only wedge fractures were analyzed, vBMD of the elliptical regions of trabecular bone exhibited the strongest correlations with both Pu (R2 = 0.5845, p < 0.001) and K (R2 = 0.6420, p < 0.001) in power regression models, however, no bone mineral measure could significantly correlate with δu. These results may suggest the type of fracture could influence the determination of bone mineral measures to predict biomechanical properties of vertebral bodies.

Background: Adolescent idiopathic scoliosis (AIS) curves of 50° to 75° are inclined to progress and are thus indicated for surgery. Nevertheless, the natural history of curves of 40° to 50° following skeletal maturity remains uncertain and presents a clinical dilemma. The aim of this study was to determine the prevalence, rate, and prognostic indicators of curve progression within this patient group. Methods: This was a retrospective study of 73 skeletally mature patients with AIS. Following yearly or more frequent follow-up, patients were stratified as having no progression (<5° increase) or progression (≥5° increase). Those with progression were further differentiated as having standard progression (<2° increase/year) or fast progression (≥2° increase/year). Radiographic parameters (coronal balance, sagittal balance, truncal shift, apical translation, T1 tilt, apical vertebral wedging) and height were determined on skeletal maturity. Parameters that were significantly associated with progression were subject to receiver operating characteristic (ROC) curve analysis. Results: The average period of post-maturity follow-up was 11.8 years. The prevalence of progression was 61.6%. Among those with progression, the curve increased by a mean of 1.47° ± 1.22° per year, and among those with fast progression, by 3.0° ± 1.2° per year. Thoracic apical vertebral wedging (concave/convex vertebral height × 100) was more apparent in those with progression than in those without progression (84.1 ± 7.5 versus 88.6 ± 3.1; p = 0.003). Increased coronal imbalance (C7 plumb line to central sacral vertebral line) differentiated those with fast progression from others (16.0 ± 11.0 versus 8.7 ± 7.7 mm; p = 0.007). An ROC curve of height-corrected coronal balance demonstrated an area under the curve (AUC) of 0.722, sensitivity of 75.0%, and specificity of 72.5% in identifying fast progression. An ROC curve of height-corrected coronal balance together with apical vertebral wedging to identify those with progression demonstrated an AUC of 0.746, with specificity of 93.7% and sensitivity of 64.5%. Conclusions: While the majority of curves progressed, the average rate of progression was slow, and thus, yearly observation was a reasonable management approach. Upon validation in larger cohorts, apical wedging and coronal imbalance may identity patients suited for closer monitoring and early spinal fusion. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

By deep learning technique, we present a new approach to model idiopathic single curve scoliosis. We leverage the advanced version of the recurrent neural network, that is, the long short-term memory network, to achieve the goal. We frame scoliosis as a classification problem and a regression problem. A network for classification is designed first. We perform the training and testing with real clinic records that are imputed by various tricks. Using this model, one can classify the current level of scoliosis into three predefined groups via a few publicly measurable indictors, such as body height or arm span. We also design a regression network that can predict the future progression of spine curvature. This model can infer the development in spine curvature at a certain time span according to the changes of other indictors. Both of these models are evaluated by various metrics. The experiment shows that the quantitative picture of the scoliosis can be captured by our models giving a significant performance boost. Hence, the resulting decision-support system can help to decide the necessity of a further intervene both for physicians and patients.

To assess the safety and efficacy of oral 50 mg Zoledronic acid (ZA) bisphosphate once‐a‐week for 6‐weeks to placebo among patients with chronic low back pain (cLBP) and Modic changes (MC) on MRI. A parallel, double‐blinded randomized controlled study was performed at a single center, consisted of 25 subjects with cLBP and MC that received ZA (n = 13) or placebo (n = 12). Evaluation was at baseline, 2‐weeks, 4‐weeks, 3‐months and 6‐months for assessment of LBP/leg pain intensity, disability (Oswestry‐Disability‐Index: ODI), health‐related quality‐of‐life (RAND‐36), and mental component summary scores (MCS). Type 2 MC at baseline (56%) were prevalent. In the ZA group, LBP intensity was lower at 4‐weeks in comparison to placebo (5.1 ± 1.9 vs. 6.9 ± 1.8, p = 0.038) (minimal clinically important difference [MCID] = 1.5). LBP intensity reduced at 4‐weeks and 3‐months in the ZA‐treated group in comparison to baseline. Although there was no difference in ODI, subscale RAND‐36 metrics for physical function (p = 0.038), energy/fatigue (p = 0.040) and pain (p = 0.003) were improved at 3‐months compared to placebo, with moderate significant difference for pain at 6‐months (p = 0.051). Correlated MCS scores to baseline also improved at 3‐months (p = 0.035) and 6‐months (p = 0.028) by 6.9 and 6.8, respectively, (MCID = 3.8). A reduction in MC endplate affected area at 6‐month follow‐up was noted in the ZA group (−0.67 ± 0.69 cm2), while in the placebo group no change in size was observed (0.0 ± 0.15; p = 0.041). Three subjects withdrew from the study and no long‐lasting adverse events. Oral ZA was a safe and effective treatment that reduced MC volume, improved LBP symptoms and quality‐of‐life measures in cLBP subjects with MCs.

The incidence of Modic changes (MCs) in the lumbar spine of older Japanese individuals was high; some subjects developed MCs (incidence) and had transformation of the Modic type, but few subjects demonstrated reverse transformation of Modic type. Study Design. Large-scale, prospective, population-based, longitudinal observational study. Objective. The aim of this study was to investigate the rate of incidence, transformation, and reverse transformation of Modic changes (MCs) using T1-weighted (T1W) and T2-weighted (T2W) lumbar magnetic resonance images (MRI) over a 3-year period. Summary of Background Data. Although MCs in populational study are considered significant, existing epidemiological evidence is based on cross-sectional studies only. Methods. Overall, 678 subjects (208 men, 470 women, mean age 62.1 ± 12.8 years in 2013) in both 2013 and 2016 surveys were included. The rate of change in Modic Type I (T1W: low-intensity, T2W: high-intensity), Type II (T1W: high, T2W: high), and Type III (T1W: low, T2W: low) at five endplates was analyzed over a 3-year period. An incidence of MC at each level and in the lumbar region was defined as no MC at baseline with signal changes at follow-up. Transformation was defined as Type I or II MC at baseline with conversion at follow-up Type II from Type I or Type III MC from Type I and II. Furthermore, reverse transformation was defined as Type I, II, or III MC at baseline, with at least one endplate showing a reversion in Modic type (no MC for baseline Type I; no MC and Type I for baseline Type II; no MC, Type I or Type II for baseline Type III) at follow-up. Results. Overall, 3390 endplates were included. For 3 years, the incidence, transformation, and reverse transformation of MCs were seen in 395 (11.7%), 84 (2.5%), and 11 (0.3%) endplates, respectively. The highest levels of incidence, transformation, and reverse transformation were at L2/3 (96 [14.2%] endplates), L5/S1 (32 [4.7%] endplates), and L2/3 (5 [0.7%] endplates), respectively. Conclusion. This study revealed a high incidence of MCs at the upper lumbar levels and transformation at the lower lumbar levels. Reverse transformation of MCs occurs but are rare. Level of Evidence: 2

Study Design. Prospective randomized controlled trial. Objective. To compare clinical effectiveness and quality of life (QoL) of the 3D-printed orthosis (3O) and conventional orthosis (CO) for adolescent idiopathic scoliosis (AIS). Summary of Background Data. Using 3D printing technology to design and fabricate orthoses to manage AIS aiming to improve in-orthosis correction and patients’ compliance that are considered essential factors of effective treatment. Clinical evaluation was conducted to study the effectiveness of this innovative method. Methods. Thirty females with AIS who met the criteria (age 10–14, Cobb 20–40°, Risser sign 0–2, ≤12 months after menarche) were recruited. Subjects were randomly allocated to the 3O group (n = 15, age 12.4, Cobb 31.8°) and CO group (n = 15, age 12.0, Cobb 29.3°). All patients were prescribed for full-time wearing (23 hours/d) and follow-up every 4 to 6 months until bone maturity. Compliance was monitored by thermosensors, while QoL was assessed using three validated questionnaires. Results. Comparable immediate in-orthosis correction was observed between 3O (−11.6°, P < 0.001) and CO groups (−12.9°, P < 0.001). In the QoL study via SRS-22r, the 3O group got worse results after 3 months in aspects of function, self-image, and mental health (−0.5, −0.6, −0.7, P < 0.05) while the CO group had worse results in aspects of self-image and mental health (−0.3, −0.3, P < 0.05). No significant difference was found in QoL assessments between groups. After 2 years of follow-up, 22 patients were analyzed with 4 dropouts in each group. Comparable angle reduction was observed in both groups (3O: −2.2°, P = 0.364; CO: −3.5°, P = 0.193). There was one subject (9.1%) in the 3O group while two subjects (18.2%) in the CO group had curve progression >5°. Daily wearing hours were 1.9 hours longer in the 3O group than the CO group (17.1 vs. 15.2 hours, P = 0.934). Conclusion. The 3O group could provide comparable clinical effects as compared with the CO group while patients with 3O showed similar compliance and QoL compared to those with CO. Level of Evidence: 1

In treating recalcitrant low back pain, extreme lateral lumbar interbody fusion (XLIF) with a large cage is reported to have better stability compared to approach of transforaminal lumbar interbody fusion (TLIF) using a small cage. In addition, bilateral pedicle screw fixation (PSF) in comparison with unilateral fixation achieved no inferior fusion rate, but with a significant reduction in operation time and blood loss. The aim of the study was to understand the mechanism underpinning the stability of lumbar interbody fusion using different cage sizes with unilateral or bilateral PSF. A computer model of human lumbar vertebrae L4 and L5 with implants was reconstructed based on CT scans and simulated in Ansys Workbench. Simulation results demonstrated that for either XLIF or TLIF cages, the maximum values of rod stress were comparable with bilateral and unilateral PSF. However, the stability was considerably reduced with unilateral PSF for TLIF due to significantly increased facet joint strain for TLIF; whereas for XLIF with left unilateral PSF, the max facet joint strain was comparable to bilateral PSF, possibly due to facet tropism of this specific subject.

Background Although Risser stages are visible on the same radiograph of the spine, Risser staging is criticized for its insensitivity in estimating the remaining growth potential and its weak correlation with curve progression in patients with adolescent idiopathic scoliosis. Risser staging is frequently accompanied by other skeletal maturity indices to increase its precision for assessing pubertal growth. However, it remains unknown whether there is any discrepancy between various maturity parameters and the extent of this discrepancy when these indices are used concurrently to assess pubertal growth landmarks, which are important for the timing of brace initiation and weaning. Questions/purposes (1) What is the chronologic order of skeletal maturity grades based on the growth rate and curve progression rate in patients with adolescent idiopathic scoliosis? (2) What are the discrepancies among the grades of each maturity index for indicating the peak growth and start of the growth plateau, and how do these indices correspond to each other? (3) What is the effectiveness of Risser staging, Sanders staging, and the distal radius and ulna classification in assessing peak growth and the beginning of the growth plateau? Methods Between 2014 and 2017, a total of 13,536 patients diagnosed with adolescent idiopathic scoliosis were treated at our tertiary clinic. Of those, 3864 patients with a radiograph of the left hand and wrist and a posteroanterior radiograph of the spine at the same visits including initial presentation were considered potentially eligible for this study. Minimum follow-up was defined as 6 months from the first visit, and the follow-up duration was defined as 2 years since initial consultation. In all, 48% (1867 of 3864) of patients were eligible, of which 26% (485 of 1867) were excluded because they were prescribed bracing at the first consultation. These patients visited the subsequent clinics wearing the brace, which might have affected body height measurement. Six percent (117 of 1867) of eligible patients were also excluded as their major coronal Cobb angle reached the surgical threshold of 50° and had undergone surgery before skeletal maturity. Another 21% (387 of 1867) of patients were lost before minimum follow-up or had incomplete data, leaving 47% (878) for analysis. These 878 patients with 1139 skeletal maturity assessments were studied; 74% (648 of 878) were girls. Standing body height was measured in a standardized manner by a wall-mounted stadiometer. Several surgeons measured curve magnitude as per routine clinical consultation, skeletal maturity was measured according to the distal radius and ulna classification, and two raters measured Risser and Sanders stages. Reliability tests were performed with satisfaction. Data were collected for the included patients at multiple points when skeletal maturity was assessed, and only up to when brace wear started for those who eventually had bracing. The growth rate and curve progression rate were calculated by the change of body height and major coronal Cobb angle over the number of months elapsed between the initial visit and next follow-up. At each skeletal maturity grading, we examined the growth rate (in centimeters per month) and curve progression rate (in degrees per month) since the skeletal maturity assessment, as well as the mean age at which this maturity grading occurred. Each patient was then individually assessed for whether he or she was experiencing peak growth and the beginning of growth plateau at each timepoint by comparing the calculated growth rate with the previously defined peak growth rate of ≥ 0.7 cm per month and the beginning of growth plateau rate of ≤ 0.15 cm per month in this adolescent idiopathic scoliosis population. Among the timepoints at which the peak growth and the beginning of growth plateau occurred, the median maturity grade of each maturity index was identified as the benchmark grade for comparison between indices. We used the McNemar test to investigate whether pubertal growth landmarks were identified by specific maturity grades concurrently. We assessed the effectiveness of these skeletal maturity indices by the difference in proportions (%) between two benchmark grades in indicating peak growth and the growth plateau. Results For girls, the chronological order of maturity grades that indicated peak growth was the radius grade, ulna grade, Sanders stage, and Risser stage. Curve progression peaked between the age of 11.6 and 12.1 years at a similar timing by all maturity indices for girls but was inconsistent for boys. For both sexes, radius (R) grade 6, ulna (U) grade 5, Sanders stage (SS) 3, and Risser stage 0+ were the median grades for peak growth, whereas Risser stage 4, R8/9, U7/8, and SS6/7 indicated the beginning of the growth plateau. The largest discrepancy between maturity indices was represented by Risser stage 0+, which corresponded to six grades of the Sanders staging system (SS2 to…