Comprehensive assessment of global spinal sagittal alignment and related normal spinal loads in a healthy population.

Abnormal postoperative global sagittal alignment (GSA) is associated with an increased risk of mechanical complications after spinal surgery. Typical assessment of sagittal alignment relies on a few selected measures, disregarding global complexity and variability of the sagittal curvature. The normative range of spinal loads associated with GSA has not yet been considered in clinical evaluation. The study objectives were to develop a new GSA assessment method that holistically describes the inherent relationships within GSA and to estimate the related spinal loads. Vertebral endplates were annotated on radiographs of 85 non-pathological subjects. A Principal Component Analysis (PCA) was performed to derive a Statistical Shape Model (SSM). Associations between identified GSA variability modes and conventional alignment measures were assessed. Simulations of respective Shape Modes (SMs) were performed using an established musculoskeletal AnyBody model to estimate normal variation in cervico-thoraco-lumbar loads. The first six principal components explained 97.96% of GSA variance. The SSM provides the normative range of GSA and a visual representation of the main variability modes. Normal variation relative to the population mean in identified alignment features was found to influence spinal loads, e.g. the lower bound of the second shape mode (SM2-2σ) corresponds to an increase in L4L5-compression by 378.64 N (67.86%). Six unique alignment features were sufficient to describe GSA almost entirely, demonstrating the value of the proposed method for an objective and comprehensive analysis of GSA. The influence of these features on spinal loads provides a normative biomechanical reference, eventually guiding surgical planning of deformity correction in the future.

Association of Spinal Corrective Surgery With Abdominal Aorta Length in Patients With Adult Spinal Deformity.

Introduction This research aimed to explore the relationship between spinal characteristics and the length of the abdominal aorta in adult spinal deformity (ASD) patients who underwent corrective spinal surgery. We hypothesized that adjusting spinal alignment might affect the abdominal aorta's length. Methods This study included thirteen patients with ASD (average age: 63.0 ± 8.9 years; four males and nine females) who received spinal correction surgery. We measured both pre-operative and post-operative spinal parameters, including thoracolumbar kyphosis (TLK), and calculated their differences (Δ). The length of the aorta (AoL) was determined using an automated process that measures the central luminal line from the celiac artery's bifurcation to the inferior mesenteric artery. This measurement was made using contrast-enhanced computed tomography for three-dimensional aortic reconstruction. We compared the pre-operative and post-operative AoLs and their differences (Δ). The study examined the correlation between changes in spinal parameters and changes in AoL. Results Post-operatively, there was an increase in aortic length (ΔAoL: 4.2 ± 4.9 mm). There was a negative correlation between the change in TLK and the change in AoL (R2 = 0.45, p = 0.012, ß = -0.21). No significant correlations were found with other spinal parameters. Conclusions The abdominal aorta can elongate by 4.8% after spinal corrective surgery in patients with ASD. The degree of elongation of the abdominal aorta is associated with spinal alignment correction.

Impact of Surgical Resection Without Spinal Fusion for Thoracic Dumbbell Tumors on Postoperative Global Spinal Sagittal Alignment and Clinical Outcomes.

STUDY DESIGN: A retrospective comparative study. OBJECTIVES: This study investigated radiographical changes in global spinal sagittal alignment (GSSA) and clinical outcomes after tumor resection without spinal fusion in patients with thoracic dumbbell tumors. METHODS: Thirty patients with thoracic dumbbell tumors who were followed up for at least 3 years were included in this study. Variations in the outcome variables were analyzed using individual GSSA parameters measured on radiography. Clinical outcomes were assessed using the modified McCormick scale (MMCS), Japan Orthopaedic Association (JOA) score, and visual analog scale (VAS). To assess the impact of the affected levels on these outcomes, we divided the patients into three groups according to the location of the tumor (upper [T1-4], middle [T5-8], or lower [T9-12] thoracic spine). RESULTS: The GSSA parameters (cervical lordosis, T1 slope, thoracic kyphosis [global, upper, middle, and lower], thoracolumbar kyphosis, lumbar lordosis, sacral slope, pelvic incidence, and pelvic tilt) of all the patients did not change significantly after surgery. Eleven of thirty patients had preoperative gait disturbances but they could walk without support (MMCS grade I or II) at the final follow-up. The JOA score and VAS showed significant postoperative improvements. No statistically significant differences were observed in each postoperative sagittal profile or clinical outcome between the upper, middle, and lower groups. CONCLUSIONS: Tumor resection without spinal fusion did not affect the various GSSA parameters and resulted in satisfactory clinical outcomes, indicating that spinal fusion may not always be necessary when resecting thoracic dumbbell tumors.

Spinous Process-Splitting Laminectomy Approach for Tumor Excision at Conus Medullaris or Cauda Equina Level Results in Satisfactory Clinical Outcomes Without Affecting Global Spinal Sagittal Alignment.

STUDY DESIGN: Retrospective comparative study. OBJECTIVES: The present study investigated radiographical changes in global spinal sagittal alignment (GSSA) and clinical outcomes following tumor resection using spinous process-splitting laminectomy (SPSL) approach without fixation in patients with conus medullaris (CM) or cauda equina (CE) tumor. METHODS: Forty-one patients with CM or CE tumor (19 males, 22 females, mean age at surgery of 52.9 ± 13.0 years) were included in this study. The variations of outcome variables were analyzed in various GSSA profiles using radiographic outcomes. The clinical outcomes were assessed using Japan Orthopaedic Association (JOA) score and JOA back pain evaluation questionnaire (JOABPEQ). RESULTS: In all cases, the various GSSA parameters (sagittal vertical axis, C2-7 lordosis, T1 slope, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis [LL; upper, middle, and lower], sacral slope, pelvic incidence, and pelvic tilt) did not significantly change in the 2-years postoperative period. Moreover, age at surgery, the number of resected laminae, preoperative T12-L2 kyphosis, or LL did not affect the postoperative changes in T12-L2 kyphosis or LL, and had no statistically significant correlation among them. The scores of each postoperative JOA domain and the Visual Analogue Scale included in the JOABPEQ were significantly improved. There was no statistical significant group difference in each sagittal profile or clinical outcomes between CM and CE groups postoperatively. CONCLUSIONS: Tumor resection using SPSL approach did not affected the various GSSA parameters examined and resulted in satisfactory clinical outcomes, indicating that SPSL approach is a suitable surgical technique for patients with CM or CE tumor.

Can Proximal Junctional Kyphosis after Surgery for Adult Spinal Deformity Be Predicted by Preoperative Dynamic Sagittal Alignment Change with 3D Gait Analysis? A Case-Control Study.

BACKGROUND: Severe spinal deformity is a risk factor for proximal junctional kyphosis (PJK) in surgery for adult spinal deformity (ASD). However, standing X-ray imaging in patients with dynamic spinal imbalance can underestimate the risk of PJK because of compensation mechanisms. This study aimed to investigate whether preoperative dynamic spinal alignment can be a predictive factor for PJK. METHODS: We retrospectively included 27 ASD patients undergoing three-dimensional (3D) gait analysis before surgery. Dynamic spinal parameters were obtained using a Nexus motion capture system (Vicon, Oxford, UK). The patients were instructed to walk as long as possible around an oval walkway. The averaged dynamic parameters in the final lap were compared between patients with PJK (+) and with PJK (-). RESULTS: PJK occurred in seven patients (26%). The dynamic angle between the thoracic spine and pelvis was larger in patients with PJK (+) than in those with PJK (-) (32.3 ± 8.1 vs. 18.7 ± 13.5 °, p = 0.020). Multiple logistic regression analysis identified this angle as an independent risk factor for PJK. CONCLUSIONS: Preoperative thoracic anterior inclination exacerbated by gait can be one of preoperative independent risk factors for PJK in patients undergoing corrective surgery for ASD.

Decreased muscle mass and strength affected spinal sagittal malalignment.

PURPOSE: Correction surgeries for spinal malalignment showed good clinical outcomes; however, there were concerns including increased invasiveness, complications, and impact on medico-economics. Ideally, an early intervention is needed. To better understand the patho-mechanism and natural course of spinal alignment, the effect of factors such as muscle mass and strength on spinal sagittal imbalance were determined in a multicenter cross-sectional study. METHODS: After excluding metal implant recipients, 1823 of 2551 patients (mean age: 69.2 ± 13.8 years; men 768, women 1055) were enrolled. Age, sex, past medical history (Charlson comorbidity index), body mass index (BMI), grip strength (GS), and trunk muscle mass (TM) were reviewed. Spinal sagittal imbalance was determined by the SRS-Schwab classification. Multiple comparison analysis among four groups (Normal, Mild, Moderate, Severe) and multinomial logistic regression analysis were performed. RESULTS: On multiple comparison analysis, with progressing spinal malalignment, age in both sexes tended to be higher; further, TM in women and GS in both sexes tended to be low. On multinomial logistic regression analysis, age and BMI were positively associated with spinal sagittal malalignment in Mild, Moderate, and Severe groups. TM in Moderate and Severe groups and GS in the Moderate group were negatively associated with spinal sagittal malalignment. CONCLUSION: Aging, obesity, low TM, and low GS are potential risk factors for spinal sagittal malalignment. Especially, low TM and low GS are potentially associated with more progressed spinal sagittal malalignment. Thus, early intervention for muscles, such as exercise therapy, is needed, while the spinal sagittal alignment is normal or mildly affected.

Static and dynamic stabilometric force platform study of spinopelvic anterior sagittal imbalance.

BACKGROUND DATA: Anterior sagittal imbalance (ASI) is a severity factor in spinal pathology. Stabilometric study of the dynamic position of the center of pressure (CoP) assesses orthostatic control. These analyses provide the energy expenditure used for this control. HYPOTHESIS: Stabilometric signs are associated with ASI indicate increased energy expenditure. PATIENTS AND METHODS: Healthy male volunteers were subjected to reversible ASI induced by wearing a kyphotic thermoformed thoracolumbar corset. The deformation was assessed by C7 tilt on EOS whole-spine views. Static and dynamic posturographic force platform study was performed under conditions of anteroposterior and mediolateral instability. Mean CoP position (Xmean, Ymean) was studied on statokinesigram, with scatter assessed as confidence ellipse (CE). Path length according to CE surface (LAS) indicated energy expenditure. The stabilogram quantified displacement over time as lengths (Lx, Ly) and amplitudes (Ax, Ay). RESULTS: The corset significantly increased C7 tilt (p<0.0001). This did not significantly change mean CoP positions (Xmean and Ymean), but LAS was significantly increased (p=0.003). Static tests showed changes in Ly (p=0.0008) and Ax (p=0.003), and dynamic tests showed changes in Ly (p<0.0001), Lx (p<0.0001), Ax (p<0.0001), Ay (p<0.05) and CE (p<0.004). DISCUSSION: Posturographic parameters were impacted by inducing ASI in healthy subjects. Significant differences were seen in stabilography, CE and LAS, were greater on dynamic testing, and correlated with radiologic sagittal balance. Force platforms can reveal increased energy expenditure in maintaining posture. LEVEL OF EVIDENCE: II; Single-center prospective study involving healthy volunteers.

Factors associated with pain-related disorders and gait disturbance scores from the Japanese orthopedic association back pain evaluation questionnaire and Oswestry Disability Index in patients with osteoporosis.

In the current study, multivariate analyses were performed to determine factors associated with low back pain (LBP) in patients with osteoporosis. Aging, high bone turnover, obesity, low trunk muscle mass, spinal global sagittal malalignment, and a high number of previous vertebral fractures were potential independent risk factors of pain-related disorders, gait disturbance, or ADL deficit due to LBP. PURPOSE: Patients with osteoporosis often experience low back pain (LBP) even in the absence of acute fractures. This study identifies factors that may affect questionnaires about LBP. METHODS: The data of 491 patients with osteoporosis were retrospectively reviewed. Data included patient age, sex, body mass index (BMI), bone mineral density of the lumbar spine, tartrate-resistant acid phosphatase 5b level (TRACP5b), trunk muscle mass, sagittal vertical axis (SVA), previous vertebral fractures, secondary osteoporosis, controlling nutritional status score, pain-related disorders and gait disturbance scores from the Japanese Orthopedic Association Back Pain Evaluation questionnaire (JOABPEQ), and Oswestry disability index (ODI) scores for activities of daily living (ADL) deficit. Patients with scores of 100 for each subsection of the JOABPEQ, or an ODI scores < 12 were considered to not have dysfunction (dysfunction (-) group). Multivariate analyses were used to determine variables associated with dysfunction. RESULTS: Pain-related disorders score of JOABPEQ was associated with aging, high BMI, and high SVA. Aging, high TRACP5b, high BMI, low TM, high SVA, and more previous vertebral fractures were associated with gait disturbance score of JOABPEQ. ODI scores were associated with high BMI, low TM, high SVA, and more previous vertebral fractures. CONCLUSIONS: Aging, high bone turnover, obesity, a low TM, spinal global sagittal malalignment, and a high number of previous VFs were potential independent risk factors of pain-related disorders or gait disturbance according to the JOABPEQ or ODI score in patients with osteoporosis.

Association between pre-operative sagittal alignment and radiographic measures of decompression following cervical laminectomy: a retrospective cohort study.

BACKGROUND: The primary purpose of this study was to determine the association between pre-operative cervical sagittal alignment and the extent of cord decompression in the form of increased spinal cord width and cerebrospinal fluid (CSF) space in front of and behind the cord in patients undergoing laminectomy for cervical spondylotic myelopathy (CSM). Secondary objectives included an assessment of the correlation between increasing numbers of levels decompressed and the post-operative cervical spine sagittal alignment, the effect of laminectomy on the change in alignment, as well as effect of laminectomy on pre-existing spinal cord signal abnormality. METHODS: This retrospective cohort study included patients who underwent cervical laminectomies, without fusion, between 2015 and 2020. Chart review was used to collect baseline variables. Cervical sagittal alignment, width of the spinal cord, and the CSF space in-front and behind the cord was measured pre-operatively and post-operatively using magnetic resonance imaging (MRI) scans for each patient. The correlation between change in measured parameters and pre-operative cervical sagittal alignment was assessed using Spearman's correlation. RESULTS: Thirty-five patients were included. Average age was 65.29±10.98 years old. The majority of patients (80%) underwent laminectomies at 3-4 levels. Average pre-operative sagittal alignment determined by the Cobb angle was 6.05°±14.17°, while the average post-operative Cobb angle was 3.15°±16.64°. The change in Cobb angle was not statistically significant (P=0.998). Eleven patients (32%) had pre-operative kyphotic sagittal alignment. The average time from surgery to post-operative MRI scan was 20.44±13.18 months (range, 3-39; median, 18.5; IQR, 23.5). There was no statistically significant association between increasing levels of decompression and change in alignment (P=0.546). Cord signal abnormality persisted after decompression. There was a moderate correlation between lordotic pre-operative cervical sagittal alignment and change in space in-front of the cord (correlation coefficient 0.337, P=0.048) and change in cord width (correlation coefficient 0.388, P=0.021). CONCLUSIONS: Severity of pre-operative kyphotic sagittal alignment is associated with decreased spinal cord drift and extent of decompression. The pre-operative sagittal alignment is not significantly associated with the change in post-operative alignment. Increasing number of levels decompressed does not worsen a kyphotic cervical spine sagittal alignment.

Prevalence and Characteristics of Spinal Sagittal Malalignment in Patients with Osteoporosis.

Spinal sagittal malalignment due to vertebral fractures (VFs) induces low back pain (LBP) in patients with osteoporosis. This study aimed to elucidate spinal sagittal malalignment prevalence based on VF number and patient characteristics in individuals with osteoporosis and spinal sagittal malalignment. Spinal sagittal alignment, and VF number were measured in 259 patients with osteoporosis. Spinal sagittal malalignment was defined according to the SRS-Schwab classification of adult spinal deformity. Spinal sagittal malalignment prevalence was evaluated based on VF number. In patients without VFs, bone mineral density, bone turnover markers, LBP scores and health-related quality of life (HRQoL) scores of normal and sagittal malalignment groups were compared. In 205 of the 259 (79.2%) patients, spinal sagittal malalignment was detected. Sagittal malalignment prevalence in patients with 0, 1, or ≥2 VFs was 72.1%, 86.0%, and 86.3%, respectively. All LBP scores and some subscale of HRQoL scores in patients without VFs were significantly worse for the sagittal malalignment group than the normal alignment group (p < 0.05). The majority of patients with osteoporosis had spinal sagittal malalignment, including ≥70% of patients without VFs. Patients with spinal sagittal malalignment reported worse LBP and HRQoL. These findings suggest that spinal sagittal malalignment is a risk factor for LBP and poor HRQoL in patients with osteoporosis.

Use of a Spinal Traction Device during Work Shift in Assembly Line Workers.

Increasing back discomfort and spinal shrinkage during the workday is a problem that affects assembly line workers. The aim of this research was to analyze the effect of a spinal traction system on discomfort, spinal shrinkage, and spinal sagittal alignment in assembly line workers, who are in prolonged standing conditions during a workday. A total of 16 asymptomatic males were recruited to assess spinal shrinkage, spinal sagittal alignment, and back discomfort during the workday. The measurement was carried out in two days of work, a normal day, and the other using a spinal traction device utilized in two breaks during the workday. Assembly line workers lost height significantly on both control and intervention days. No differences were found between days. No changes were found in spinal sagittal alignment on the control day. Lumbar lordosis angle increased significantly at the end of the intervention day. The use of a spinal traction device during the workday in two breaks time did not significantly reduce the spinal shrinkage of healthy workers. Lumbar lordosis angle increased significantly at the end of the spinal traction intervention day. Prospective studies would be necessary to clarify the possible benefits of the traction device.

Relationships Between Spinal Alignment and Muscle Mass in Osteoporosis Patients Over 75 Years of Age Who Were Independent and Maintained Their Activities of Daily Living.

Introduction Elderly patients with osteoporosis often complain of back pain associated with pathological vertebral fractures caused by abnormal spinal alignment. Few reports evaluate the relationships among muscle mass, bone mineral density (BMD), sagittal spinal alignment, and low back pain. We hypothesized that decreasing muscle mass in elderly patients with osteoporosis could cause spinal alignment abnormalities. The aim of the current study were to compare the characteristics between spinal sagittal normal alignment and malalignment and to evaluate the relationships between sagittal spinal alignment and muscle mass in elderly patients with osteoporosis. Methods Fifty patients aged 75 years or more (mean age = 80.5 years) with osteoporosis were included in this study. We evaluated the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), the number of vertebral fractures (N of VFs), BMD by dual-energy X-ray absorptiometry, and trunk and skeletal muscle mass using bioelectrical impedance. Low back pain was evaluated using the Oswestry Disability Index (ODI). Corrected trunk muscle mass (trunk muscle mass index, TMI) and corrected limb muscle mass (skeletal mass index, SMI) also were measured. Patients were divided into two groups for comparison: a 'normal' group and a sagittal spinal 'malalignment' group. Multiple regression analysis was carried out to evaluate the relationship between spinal sagittal parameters and muscle mass. Results Comparisons between normal and malalignment groups for SVA, N of VFs, BMI, and SMI showed significantly higher in the malalignment group versus the normal group (p < 0.05). N of VFs, BMI, and TMI, for PT, and BMI, TMI, SMI, and ODI scores for PI-LL showed significantly higher in the malalignment group versus the normal group (p < 0.05). There were significantly more vertebral fractures in the malalignment group than in the normal group (p < 0.05). However, there were no significant differences of pure muscle mass between the two groups. When adjusted by BMD and the number of vertebral fractures, SMI and TMI were positively correlated to PI-LL and SVA (p < 0.05). Conclusion Elderly patients with osteoporosis and a sagittal spinal malalignment had more vertebral fractures and a higher risk of low back pain than patients with normal spinal alignment. Patients with a sagittal spinal malalignment who were independent and maintained their activities of daily living (ADL) showed high BMI and maintained muscle mass, independent of BMD and the N of VFs, contrary to our hypothesis.

The effect of minimally invasive lumbar decompression surgery on sagittal spinopelvic alignment in patients with lumbar spinal stenosis: a 5-year follow-up study.

OBJECTIVE: Several studies have examined the relationship between sagittal spinopelvic alignment and clinical outcomes after spinal surgery. However, the long-term reciprocal changes in sagittal spinopelvic alignment in patients with lumbar spinal stenosis after decompression surgery remain unclear. The aim of this study was to investigate radiographic changes in sagittal spinopelvic alignment and clinical outcomes at the 2-year and 5-year follow-ups after minimally invasive lumbar decompression surgery. METHODS: The authors retrospectively studied the medical records of 110 patients who underwent bilateral decompression via a unilateral approach for lumbar spinal stenosis. Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores for low-back pain (LBP), leg pain, leg numbness, and spinopelvic parameters were evaluated before surgery and at the 2-year and 5-year follow-ups. Sagittal malalignment was defined as a sagittal vertical axis (SVA) ≥ 50 mm. RESULTS: Compared with baseline, lumbar lordosis significantly increased after decompression surgery at the 2-year (30.2° vs 38.5°, respectively; p < 0.001) and 5-year (30.2° vs 35.7°, respectively; p < 0.001) follow-ups. SVA significantly decreased at the 2-year follow-up compared with baseline (36.1 mm vs 51.5 mm, respectively; p < 0.001). However, there was no difference in SVA at the 5-year follow-up compared with baseline (50.6 mm vs 51.5 mm, respectively; p = 0.812). At the 5-year follow-up, 82.5% of patients with preoperative normal alignment maintained normal alignment, whereas 42.6% of patients with preoperative malalignment developed normal alignment. Preoperative sagittal malalignment was associated with the VAS score for LBP at baseline and 2-year and 5-year follow-ups and the JOA score at the 5-year follow-up. Postoperative sagittal malalignment was associated with the VAS score for LBP at the 2-year and 5-year follow-ups and the VAS score for leg pain at the 5-year follow-up. There was a trend toward deterioration in clinical outcomes in patients with persistent postural malalignment compared with other patients. CONCLUSIONS: After minimally invasive surgery, spinal sagittal malalignment can convert to normal alignment at both short-term and long-term follow-ups. Sagittal malalignment has a negative impact on the VAS score for LBP and a weakly negative impact on the JOA score after decompression surgery.

Cervical sagittal alignment in patients with dropped head syndrome.

BACKGROUND: Dropped head syndrome (DHS) can be divided into two types, the positive sagittal vertical axis (SVA) type and the negative SVA type. However, the cervical sagittal alignment of DHS including global sagittal spinal alignment and the typical cervical alignment of the types of DHS is still unclear. The purpose of this study was to clarify the character of cervical sagittal alignment of DHS and analyze the relationship between cervical sagittal alignment and global sagittal spinal alignment. METHODS: The subjects were 35 DHS patients (10 men, 25 women, mean 71.1 years old). They were divided into two groups: negative DHS (N-DHS group, SVA < 0 mm) and positive DHS group (P-DHS group, SVA ≥ 0 mm). As control, 28 age-matched cervical spondylosis patients (CS, 21 men, 7 women, mean 67.4 years old) were analyzed. The following parameters were measured on lateral global-spine standing radiographs: cervical SVA (C2-C7SVA), O-C2A (O-C2 angle), C2 slope (C2S), C2-7A (C2-7 angle), T1 slope (T1S) and C7SVA. RESULTS: The results of measurements of each of the averaged sagittal alignment parameters were (CS, P-DHS, N-DHS): C2-7SVA(26.2 mm, 47.3 mm, 44.5 mm), O-C2 angle (35.0°, 37.1°, 39.3°), C2S (16.5°, 31.4°, 33.8°), C2-7A (9.3°, 9.9°, -16.6°), T1S (22.9°, 39.7°, 25.7°), C7SVA (35.3 mm, 51.0 mm, -43.1 mm). C2-C7SVA and C2S were significantly larger in both types of DHS compared to CS. Comparing P-DHS with N-DHS, C2-C7A and T1S were significantly smaller in N-DHS. CONCLUSIONS: O-C2A did not differ significantly among CS, P-DHS and N-DHS. In DHS patients, C2-7SVA and C2S were significantly larger than those of CS regardless of the type of DHS. The typical cervical sagittal alignment of DHS was different between P-DHS and N-DHS. In P-DHS, C2-7A and T1S were larger than those in N-DHS and the imbalance of thoraco-lumbar alignment should be noted.

Radiographic and clinical evidence: osteoarthritic knee can change surgical result for lumbar degenerative disease patient undergone surgery for 3-year follow-up: a retrospective comparative clinical study.

BACKGROUND: There is a paucity of reports clarifying the implication of knee osteoarthritis (OA) on spinal sagittal alignment of patients undergone surgery for lumbar spine. This study aimed to analyze how osteoarthritic knee affects radiographic and clinical results of degenerative lumbar disease patients undergone lumbar fusion. METHODS: We retrospectively reviewed the medical records and radiographs of 74 consecutive degenerative lumbar disease patients who underwent posterior instrumentation and fusion surgery between May 2016 and June 2017 and were followed up for minimum 3 years postoperatively. The patients were divided into 2 groups according to the severity of knee OA by Kellgren-Lawrence grading (KLG) scale (group I, KLG 1 or 2 [n = 39]; group II, KLG 3 or 4 [n = 35]). Patient demographic data, comorbidities, spinal sagittal parameters and clinical scores were extracted and compared at preoperative, postoperative 1 month and the ultimate follow-up between the groups. In radiographic assessment, sagittal alignment parameters and sagittal balance were used. In clinical assessment, the scores of Oswestry disability index (ODI) and Scoliosis Research Society questionnaire (SRS-22) were used. For the frequency analysis of categorical variables across the groups, chi-square test was used and student t tests was used to compare the differences of continuous variables. RESULTS: In radiographic assessment, TLK (thoracolumbar kyphosis), LL (lumbar lordosis), PT (pelvic tilt), C7 SVA (sagittal vertical axis) in both groups improved significantly after surgery (p <  0.05). However, LL, PT, C7SVA improved at postoperative 1 month in the group II were not maintained at the ultimate postoperative follow-up. In clinical assessment, preoperative Oswestry disability index (ODI, %) and all SRS-22 subscores of the group I and II were not different (p > 0.05). There were significant differences between the groups at the ultimate follow-up in ODI (- 25.6 vs - 12.1, p <  0.001), SRS total score (%) (28 vs 20, p = 0.037), function subscore (1.4 vs 0.7, p = 0.016), and satisfaction subscore (1.6 vs 0.6, p < 0.001). CONCLUSION: Osteoarthritic knee with KLG 3 or 4 have a negative influence on maintaining postoperative spinal sagittal alignment, balance, and the clinical outcomes achieved immediately by posterior instrumentation and fusion for lumbar degenerative disease. TRIAL REGISTRATION: This study was retrospectively registered with approval by the institutional review board (IRB) of our institution (approval number: 2018-11-007).

Low lordosis is a common finding in young lumbar disc herniation patients.

PURPOSE: The sagittal alignment of the lumbar spine and pelvis can be classified into several subtypes. It has been suggested that the risk of developing certain pathologies, such as a lumbar disc herniation (LDH) is affected by spinal sagittal profiles. The main aim of this study was to investigate the sagittal profile in young patients surgically treated for a lumbar disc herniation and if a discectomy would alter the sagittal parameters. METHODS: Sixteen active young patients (mean age 18.3 ± 3.2 SD) with a lumbar disc herniation having a discectomy were included. A classification according to Roussouly of the sagittal parameters was made by two senior spinal surgeons, both pre-operatively and post-operatively on radiographs. The distribution of sagittal parameters and spinopelvic profiles were analysed and compared to a previous established healthy normal population. RESULTS: This series of active young patients with LDH exhibited a low lumbar lordosis dominance, with Roussouly sagittal profiles type 1 and type 2 accounting for more than 75% of the examined patients. An analysis of the erect radiographs revealed no significant changes in the post-operative sagittal profile. CONCLUSIONS: This study showed that sagittal spinal alignment according to Roussouly in a young population with LDH is skewed compared with a normal population cohort. Furthermore, the lack of post-operative correction is suggestive of a non-ephemeral response to a LDH. Roussouly type 2 spinal sagittal profile may be a risk factor in young individuals suffering a disc herniation.

Correlations between the inflection point and spinal sagittal alignment in asymptomatic adults.

PURPOSE: The purposes of this study were to analyse the correlations between the inflection point (IP) and spinal sagittal parameters and to establish the corresponding linear regressions in asymptomatic adults. METHODS: A total of 205 asymptomatic subjects older than 18 years were recruited between April 2017 and September 2019. A full-spine, standing X-ray was collected for each subject. The following parameters were documented: the IP, the apices of thoracic kyphosis (TKA) and lumbar lordosis (LLA), the distance between the plumb line of the thoracic apex (TAPL) or lumbar apex (LAPL) and gravity plumb line, thoracic kyphosis (TK), lumbar lordosis (LL) and the upper arc and the lower arc of lumbar lordosis (LLUA and LLLA, respectively). The correlations between the IP and the above parameters and between the thoracic and lumbar parameters were analysed. The level of significance was P < 0.05. RESULTS: The IP was statistically correlated with age (rs = 0.327), the TKA (rs = 0.639), the TAPL (rs = 0.338), TK (rs = 0.391), the LLA (rs = 0.545), the LAPL (rs = - 0.383), the LLUA (rs = 0.371) and the LLLA (rs = - 0.145) but was not linked with LL (rs = 0.118). In addition, there were relationships between the TKA and LLA (rs = 0.397), the TAPL and LAPL (rs = - 0.357), TK and LL (rs = 0.529), TK and the LLUA (rs = 0.742) and TK and the LLLA (rs = 0.148). CONCLUSION: The IP was significantly related to spinal sagittal alignment in asymptomatic adults. Moreover, predictive formulae for sagittal parameters as a function of the IP were developed, which are helpful for surgeons in comprehending the regulatory mechanisms of spinal sagittal alignment and designing an ideal therapeutic plan. These slides can be retrieved under Electronic Supplementary Material.

Spinal Sagittal Alignment, Hospital Anxiety and Depression Scale Scores, and Patient-Reported Outcome among People with Sporting Activity.

STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aimed to investigate how participation in sporting activity affects patient-reported outcome (PRO), including Neck Disability Index (NDI), in males and females. OVERVIEW OF LITERATURE: Previously, our study reported that factors with a negative influence on the NDI in females were a lack of sporting activities. However, it was still unclear why it affected poor scores of NDI. METHODS: The subjects were 473 volunteers. They were divided into two groups (activity and non-activity) according to participation or non-participation in sporting activities using a self-filled questionnaire. The evaluation items were height, weight, grip strength, bone density, Hospital Anxiety and Depression Scale (HADS) score, standing radiographic parameters, PRO (evaluated by EuroQol-5 dimension [EQ-5D], Oswestry Disability Index [ODI]), and NDI. RESULTS: There were 101 males in the non-activity group and 69 in the activity group and 178 females in the non-activity group and 125 in the activity group. For the males, the evaluation items with significant influence were cervical lordosis (non-activity group:activity group, 17°:22°) and T1 slope minus cervical lordosis (10°:6°, p <0.05). For the females, the evaluation items with significant influence were sagittal vertical axis (28:14 mm), HADS (10.4:8.4), EQ-5D (0.79:0.86), ODI (17:12), and NDI (12:9, p <0.01). HADS and PRO in the females were significantly correlated with the EQ-5D (-0.40), ODI (0.43), and NDI (0.55). CONCLUSIONS: Males who participated in sporting activities had better cervical spine alignment but no effect on PRO. Females with sporting activities had better spinal global alignment and less mental stress. It is suggested that sporting activity in females might be associated with PRO because HADS highly correlates with PRO.

Effects of mirror placement on sagittal alignment of the spine during acquisition of full-spine standing X-Rays.

PURPOSE: The line of sight when whole-spine radiographs are taken has not been defined. In our 2012 health screening study (TOEI study), whole-spine radiographs were taken with the volunteers in the most relaxed position and with a horizontal gaze. However, in the TOEI 2014 study, a mirror was placed in front of their faces to unify their line of sight. To our knowledge, there are no reports on how the sagittal alignment changes when radiographs are taken using a mirror. The purpose of this study was to investigate how mirror placement impacted sagittal spinal alignment in whole-spine radiographs taken while standing. METHODS: Volunteers who participated in both the TOEI 2012 and 2014 studies were recruited. Pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), cervical lordosis (CL), slope of McGregor's line (McGS), and C7 sagittal vertical axis (C7 SVA) were examined using software. RESULTS: Three hundred fifty-four volunteers (142 males, 212 females, average age in 2012: 72 years) whose radiographs were evaluated in both previous studies were enrolled. The average parameters of 2012 and 2014 were: PT: 18° and 21° (P < 0.01), LL: 40° and 40°, TK: 34° and 34°, CL: 13° and 23° (P < 0.01), McGS: 2° ± 11° and - 9° ± 8° (P < 0.01), and C7 SVA: 46 and 23 mm (P < 0.01), respectively. In the Levene test, the McGS variation in 2014 [95% confidence interval (CI) 0.9-3.4] was significantly smaller than that in 2012 (95% CI - 9.7 to - 8.0, P < 0.01). CONCLUSION: The smaller McGS variation in the TOEI 2014 study suggested that mirror placement could standardize the head's position. These results showed that the mirror placement retroflexed cervical alignment and caused the head to lean backward. It is important that a mirror is placed to unify the line of sight.

Factors influencing spinal sagittal balance, bone mineral density, and Oswestry Disability Index outcome measures in patients with rheumatoid arthritis.

PURPOSE: To identify the factors influencing spinal sagittal alignment, bone mineral density (BMD), and Oswestry Disability Index (ODI) outcome measures in patients with rheumatoid arthritis (RA). METHODS: We enrolled 272 RA patients to identify the factors influencing sagittal vertical axis (SVA). Out of this, 220 had evaluation of bone mineral density (BMD) and vertebral deformity (VD) on the sagittal plane; 183 completed the ODI questionnaire. We collected data regarding RA-associated clinical parameters and standing lateral X-ray images via an ODI questionnaire from April to December 2012 at a single center. Patients with a history of spinal surgery or any missing clinical data were excluded. Clinical parameters included age, sex, body mass index, RA disease duration, disease activity score 28 erythrocyte sedimentation rate (DAS28-ESR), serum anti-cyclic citrullinated peptide antibody, serum rheumatoid factor, serum matrix metalloproteinase-3, BMD and treatment type at survey, such as methotrexate (MTX), biological disease-modifying anti-rheumatic drugs, and glucocorticoids. We measured radiological parameters including pelvic incidence (PI), lumbar lordosis (LL), and SVA. We statistically identified the factors influencing SVA, BMD, VD, and ODI using multivariate regression analysis. RESULTS: Multivariate regression analysis showed that larger SVA correlated with older age, higher DAS28-ESR, MTX nonuse, and glucocorticoid use. Lower BMD was associated with female, older age, higher DAS28-ESR, and MTX nonuse. VD was associated with older age, longer disease duration, lower BMD, and glucocorticoid use. Worse ODI correlated with older age, larger PI-LL mismatch or larger SVA, higher DAS28-ESR, and glucocorticoid use. CONCLUSIONS: In managing low back pain and spinal sagittal alignment in RA patients, RA-related clinical factors and the treatment type should be taken into consideration.