Sagittal Spinal Alignment Research Articles

Hip replacement improves lumbar flexibility and intervertebral disc height — a prospective observational investigation with standing and sitting assessment of patients undergoing total hip arthroplasty

PurposeThe pathogenic mechanism of the hip–spine syndrome is still poorly elucidated. Some studies have reported a reduction in low back pain after total hip arthroplasty (THA). However, the biomechanical mechanisms of THA acting on the lumbar spine are not well understood. The aim of the study is to evaluate the influence of THA on (1) the lumbar lordosis and the lumbar flexibility and (2) the lumbar intervertebral disc height.MethodsA total of 197 primary THA patients were prospectively enrolled. Pre- and post-operative biplanar stereoradiography was performed in standing and sitting positions. Spinopelvic parameters (lumbar lordosis (LL), pelvic tilt, sacral slope, pelvic incidence), sagittal spinal alignment (sagittal vertical axis, PI-LL mismatch (PI-LL)) and lumbar disc height index (DHI) for each segment (L1/2 to L5/S1) were evaluated. The difference between standing and sitting LL (∆LL = LLstanding − LLsitting) was determined as lumbar flexibility. Osteochondrosis intervertebralis was graded according to Kellgren and Lawrence (0–4), and patients were assigned to subgroups (mild: 0–2; severe: 3–4).ResultsLumbar flexibility increased significantly after THA (pre: 22.04 ± 12.26°; post: 25.87 ± 12.26°; p < 0.001), due to significant alterations in LL in standing (pre: 51.3 ± 14.3°; post: 52.4 ± 13.8°; p < 0.001) and sitting (pre: 29.4 ± 15.4°; post: 26.7 ± 15.4°; p = 0.01). ∆LL increased significantly in both subgroups stratified by osteochondrosis (pre/post: ΔLLmild: 25.4 (± 11.8)/29.4 ± 12.0°; p < 0.001; ΔLLsevere: 17.5 (± 11.4)/21.0 ± 10.9°; p = 0.003). The DHI increased significantly from pre-operatively to post-operatively in each lumbar segment. PI-LL mismatch decreased significantly after THA (pre: 3.5°; post: 1.4°; p < 0.001).ConclusionThe impact of THA on the spinopelvic complex was demonstrated by significantly improved lumbar flexibility and a gain in post-operative disc height. These results illustrate the close interaction between the pelvis and the vertebral column. The investigation provides new insights into the biomechanical patterns influencing the hip–spine syndrome.

Age- and Gender-based Global Sagittal Spinal Alignment in Asymptomatic Adult Volunteers: Results of the Multiethnic Alignment Normative Study (MEANS)

Multicenter Cohort. Assess normative values of sagittal spinal and lower extremity alignment in asymptomatic volunteers stratified by age and gender. Our understanding of ideal sagittal alignment is still evolving. The Multiethnic Alignment Normative Study (MEANS) investigated skeletal alignment of the largest multiethnic cohort of asymptomatic adult volunteers. We aim to assess normative values of sagittal spinal and lower extremity alignment in asymptomatic volunteers stratified by age and gender. Asymptomatic volunteers between the ages of 18-80 years were enrolled prospectively and then analyzed retrospectively from six different centers. Volunteers included reported no significant neck or back pain, nor any known spinal disorder(s). All volunteers underwent a standing full-body or full-spine low-dose stereoradiograph. MEANS consisted of 468 volunteers with a mean age of 40.4±14.8 years. Thoracic kyphosis (TK) from T4 to T12 showed a mean of 37.4±10.9°. The average L1-S1 lumbar lordosis (LL) was -57.4±11.3°. LL did not show significant differences across the five age groups. TK showed a significant difference based on age ( P <0.0001). Sagittal vertical axis increased across age groups from -14.2mm in young adults to 17.0mm in patients >64. Similar trend was seen for T1 pelvic angle with a mean of 5.0° in young adults and 13.7° in those older than age 64. Knee flexion increased across age groups without a significant change in odontoid-knee distance which is a surrogate for the center of the head aligned over the knees. In asymptomatic volunteers, sagittal alignment parameters showed a slow and steady change across age groups exemplified by an increase in TK. However, LL did not show a significant decrease across age groups. Volunteers used compensatory mechanisms such as slight pelvis retroversion, knee flexion, and neck extension to maintain an aligned sagittal posture with their head centered over their knees (odontoid-knee). 3.

Age and Gender Based Spinopelvic and Regional Spinal Alignment in Asymptomatic Adult Volunteers: Results of the Multi-Ethnic Alignment Normative Study (MEANS).

Spinal alignment can have a significant impact on a patient's overall quality of life. Predicting the ideal sagittal spinal alignment of a specific individual is still a difficult task. The Multi-Ethnic Alignment Normative Study (MEANS) investigated skeletal alignment, including the spine and lower extremities, of the largest multi-ethnic cohort of asymptomatic adult volunteers. In this analysis, the authors aim to assess normative values of spinopelvic parameters and the regional cervical, thoracic, and lumbar spinal alignment in asymptomatic volunteers stratified by age and sex. Asymptomatic volunteers between ages 18 and 80 years were enrolled prospectively from centers in France, Japan, Singapore, Tunisia, and the United States. Volunteers included reported no significant neck or back pain (Visual Analog Scale ≤2), nor any known spinal disorder(s). All volunteers underwent a standing full-body or full-spine low-dose stereoradiograph. MEANS consisted of 468 volunteers with a mean age of 40.4±14.8 years. Mean cervical lordosis from C2 to C7 was -0.4±12.7°. The T1-slope averaged 23.0±7.9° and showed strong correlation ( r =0.87) with the C7-slope mean of 19.8±8.6°. Thoracic kyphosis (TK) from T4 to T12 showed a mean of 37.4±10.9°. Average L1-S1 lumbar lordosis (LL) was -57.4±11.3°. The mean pelvic incidence (PI) measured 52.0±10.7° and pelvic tilt was 12.5±7.3°. Sacral slope averaged 39.5±8.2°. The average PI-LL was -5.4±10.7°. Approximately 60% of volunteers met the PI-LL criteria within ±10°, 8.3% were ≥10°, while 32.1% were ≤-10°. LL showed moderate correlation with PI ( r =0.53) and TK ( r =0.50), while there was no correlation between TK and PI. Multiple linear regression including PI, TK, and age resulted in the following equation LL=14.6+0.57 (PI)+0.57 (TK)-0.2 (age) ( r =0.75). LL did not change with increasing age in asymptomatic volunteers. However, TK did increase with age leading to an increase in T1-slope and a compensatory increase in cervical lordosis. TK did not correlate with PI and was an independent variable in the prediction of LL. Level II-prospective cohort study.

Effect of Spinal Sagittal Alignment in Sitting Posture on Swallowing Function in Healthy Adult Women: A Cross-Sectional Study.

Swallowing function is both directly and indirectly related to postures, such as head and cervical angle and body position. However, the effects of different sitting postures on oropharyngeal swallowing have not been investigated. This study aimed to investigate whether the change in thoracolumbar alignment affected the oropharyngeal swallowing. A total of 58 healthy adult women (mean age 22.2 ± 1.67years) without dysphagia were enrolled in this cross-sectional study. Participants were positioned in three sitting postures: comfortable sitting (CS), thoracic upright sitting (TUS), and slump sitting (SS). In each sitting posture, the kyphosis index (using a flexicurve), head and cervical angles (using a digital camera), swallowing speed (100-ml water swallowing test), and oral and articulatory function [by maximum tongue pressure (MTP) and oral diadochokinesis (ODK)] were evaluated. SS showed the largest kyphosis index and was associated with a greater anterior translation of the head. Swallowing speed was significantly decreased in SS compared with CS (p = 0.002) and TUS (p = 0.020) and ODK was significantly decreased in SS compared with other postures, for both /ta/ (p = 0.004) and /ka/ (p < 0.001) syllables. Further, MTP tended to decrease in SS compared with TUS (p = 0.064). Our results suggest that changes in sitting posture with different thoracolumbar alignments affect swallowing speed and oral and articulatory function. Consequently, adjustments to reduce sitting postural kyphosis may improve swallowing speed and oral and articulatory function.

Spinal sagittal alignment and postoperative adding-on in patients with adolescent idiopathic scoliosis after surgery

IntroductionSurgery for patients with adolescent idiopathic scoliosis (AIS) may change spinal sagittal alignment, and postoperative adding-on may affect spinal sagittal balance after reconstruction. This study was to investigate the effect of surgery on spinal sagittal alignment and the relationship between postoperative adding-on and spinal sagittal balance in patients with AIS. HypothesisThe hypothesis of this study was that the effect of surgery on AIS was associated with recovery of the spinal sagittal plane and that presence of postoperative adding-on might affect the spinal sagittal balance.Materials and methods This retrospective study enrolled 22 patients who received surgical treatment. Clinical, imaging and follow-up data were analyzed. ResultsAfter surgery, T1 slope (T1S) and thoracic kyphosis (TK) were significantly (P<0.05) lower in patients with postoperative adding-on (16.73°±6.12° for T1S and 28.95°±11.3° for TK) than those without adding-on (24.82°±8.59° for T1S and 40.29°±12.08° for TK). At the last follow-up, cervical lordosis (CL), T1S, and TK were significantly (P<0.05) lower in patients with adding-on (3.05°±11.41° for CL, 22.12°±3.68° for T1S, and 37.89°±8.97° for TK) than those without adding-on (15.94°±°13.6 for CL, 28.86°±4.26° for T1S, and 47.64°±7.1° for TK). The Cobb angle was significantly (19.65°±8.69° vs. 50.66°±11.46°; P<0.001) decreased after compared with that before surgery. At the final follow-up, the Cobb angle (26.48°±9.61° vs. 19.65°±8.69°, P<0.001), T1S (24.87°±5.11° vs. 20.04°±8.13°), and TK (41.88°±9.45° vs 33.53°±12.71°) all significantly (P<0.01) increased compared with those immediately after surgery. The Cobb angle significantly (26.48°±9.61° vs. 50.66°±11.46°, P<0.001) decreased while CL, T1S, and TK all significantly (8.32°±13.67° vs 2.47°±14.42° for CL, T1S 24.87°±5.11° vs. 21.28°±5.88° for T1S, and 41.88°±9.45° vs. 33.13°±10.97° for TK, P<0.05) increased at the final follow-up compared with those before surgery. DiscussionSurgery affects spinal sagittal alignment, and postoperative adding-on may affect spinal sagittal balance after reconstruction. Surgery as the ultimate approach for AIS has good effects but may result in some side effects. Level of proofIII, retrospective cohort study.

Association of the Psoas Muscle Index and Sagittal Spinal Alignment With Patient-Reported Outcomes After Total Hip Arthroplasty: A Minimum 5-Year Follow-Up.

The aim of this study is to assess the association between a spinopelvic malalignment and patient-reported perception of the hip as being "artificial" after total hip arthroplasty (THA). This is a critical issue as an age-related spinopelvic mismatch has been postulated to be associated with the risk of poor outcomes after THA. This is a retrospective case-control study of 274 THAs (244 of whom were women), with a mean follow-up of 6.2 (range 5.0-8.2) years. Hip perception was assessed by asking subjects whether their joint felt "natural" or "artificial." The association between an artificial perception and the following factors was evaluated: age, gender, psoas muscle index (PMI, cross-sectional area of bilateral psoas at L3 divided by height squared), and spinopelvic measures using logistic regression analysis. An artificial hip perception (130 hips, 47.4%) was associated with a lower PMI (P= .016), Hip Disability and Osteoarthritis Outcome Score Joint Replacement score (P= .035), EuroQol 5-Dimension score (P= .041), and a higher incidence of a pelvic incidence-minus-lumbar lordosis (PI-LL) mismatch >10° (P< .001). A flatback deformity (odds ratio 2.24, 95% confidence interval 1.22-6.31, P= .001) and PMI (odds ratio 0.61, 95% confidence interval 0.34-0.82, P= .012) were predictive of an artificial perception. With the threshold of PI-LL set to 10°, PMI (P= .034), Hip Disability and Osteoarthritis Outcome Score Joint Replacement score (P < .001), joint perception (P= .020), EuroQol 5-Dimension score (P= .028), pain (P= .031), and satisfaction (P < .001) differed between the 2 groups. A flatback deformity is associated with the risk of an artificial perception post-THA, especially in patients with sarcopenia. PMI and PI-LL measurements may help predict THA outcomes.

Hip-Spine Relationship between Sagittal Balance of the Lumbo-Pelvi-Femoral Complex and Hip Extension Capacity: An EOS Evaluation in a Healthy Caucasian Population.

A prospective study of healthy volunteers. The influence of the sagittal alignment of the spine and its influence on the extension reserve have been reported in the literature. However, specific analysis of the intrinsic coxofemoral and extrinsic pelvic component in subjects without any spinal or hip pathologies remains poorly reported. The aim of this study was to categorize the hip extension capacity, or extension reserve (ER), in relation to spinal sagittal alignment whilst standing, in a young healthy population. We hypothesized that the global extension reserve (GER) of the hip joint was influenced by the sagittal spinopelvic alignment. We evaluated the ER of 120 healthy Caucasian volunteers (56 females (46.7%), 74 males (53.3%); mean age 25.6years), using low dose radiographs from an EOS® X-ray imaging system in 2 functional positions; neutral standing position and in a forward lunge position. The GER is defined as the sum of the intrinsic (hip) extension reserve (IER) and the extrinsic (pelvic) extension reserve (EER). Cases were grouped into 4 sagittal alignment subtypes according to the Roussouly classification, and analyzed. Global extension reserve values were not significantly different between the 4 Roussouly subtypes (P = .094), nor between patients with a sacral slope (SS) <35° (types 1/2) and ≥ 35° (type 3/4) (P = .837). Statistically significant differences were seen between IER in each subtype (P = .015), and EER (P = .006). No difference in ER was seen between subtypes regarding pelvic incidence (PI). An inverse relationship was found between IER and EER among Roussouly subtypes. The range of motion of the pelvis and the hip joint was higher in patients with a greater sacral slope.

The Short-Term Changes of the Sagittal Spinal Alignments After Acute Vertebral Compression Fracture Receiving Vertebroplasty and Their Relationship With the Change of Bathel Index in the Elderly.

IntroductionFragility vertebral compression fractures (VCFs) are of major concern due to aging populations worldwide, which may occur after a fall from standing or due to severe osteoporosis, impacting greatly the life quality of the elderly. This study thus determined the factors independently associated with poor functional recovery from a new VCF and changes in sagittal spinal alignment after vertebroplasty in elderly patients with osteoporosis.Materials and MethodsThe data were collected from patients older than 70 years and diagnosed with a new VCF. Logistic regression analysis was performed to determine factors independently associated with function and radiographic status.ResultsWe enrolled 8 male and 34 female patients with a mean age of 80.74 ± 8.31 years between January and July 2020. Compared with preoperative data, post-vertebroplasty lumbar sagittal alignments and functional scores improved significantly, and function recovered gradually over 12 weeks. Climbing stairs was the most influential performance indicator at the beginning of the recovery process. At each postoperative follow-up, changes in the C7-sacrum sagittal vertical axis exhibited an influence on functional recovery. Male patients were better able to move from a chair to a bed at the 2-week postoperative follow-up, and positive changes in the spino-sacral angle led to improved function in terms of stair climbing at the 6-week postoperative follow-up.ConclusionsVertebroplasty seemed to be effective for functional recovery related to sagittal spinal alignment improvement of the elderly with VCFs during postoperative 12 weeks, which may be a critical stage for the recovery for their life activities. The recovery rate for stair climbing after vertebroplasty was slower than for the other functional performance indicators in our study. In addition, if a patient was unable to demonstrate a marked improvement in sagittal alignment, they were likely to have ongoing impaired function and a poor prognosis after surgery.

Thoracic kyphosis in light of lumbosacral alignment in thoracic adolescent idiopathic scoliosis: recognition of thoracic hypokyphosis and therapeutic implications

BackgroundThe uniqueness of spinal sagittal alignment in thoracic adolescent idiopathic scoliosis (AIS), for example, the drastically smaller thoracic kyphosis seen in some patients, has been recognized but not yet fully understood. The purpose of this study was to clarify the characteristics of sagittal alignment of thoracic AIS and to determine the contributing factors.MethodsWhole spine radiographs of 83 thoracic AIS patients (73 females) were analyzed. The measured radiographic parameters were the Cobb angle of thoracic scoliosis, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (C7 SVA), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Additionally, max-LL, which was defined as the maximum lordosis angle from the S1 endplate, the inflection point between thoracic kyphosis and lumbar lordosis, and the SVA of the inflection point (IP SVA) were measured. The factors significantly related to a decrease in TK were assessed by stepwise logistic regression analysis. In addition, cluster analysis was performed to classify the global sagittal alignment.ResultsThe significant factors for a decrease in TK were an increase in SS (p = 0.0003, [OR]: 1.16) and a decrease in max-LL (p = 0.0005, [OR]: 0.89). According to the cluster analysis, the global sagittal alignment was categorized into the following three types: Type 1 (low SS, low max-LL, n = 28); Type 2 (high SS, low max-LL, n = 22); and Type 3 (high SS, high max-LL, n = 33).ConclusionsIn thoracic AIS, a decreased TK corresponded to an increased SS or a decreased max-LL. The sagittal alignment of thoracic AIS patients could be classified into three types based on SS and max-LL. One of these three types includes the unique sagittal profile of very small TK.

Effectiveness and cost-effectiveness of dynamic bracing versus standard care alone in patients suffering from osteoporotic vertebral compression fractures: protocol for a multicentre, two-armed, parallel-group randomised controlled trial with 12 months of follow-up

IntroductionPatients with osteoporosis may suffer from a fracture after minimal trauma. Osteoporotic vertebral compression fractures (OVCFs) are among the most common fractures, often leading to substantial pain. There is a...

Lower-Limb Range of Motion Predicts Sagittal Spinal Misalignments in Children: A Case-Control Study

The main objective of this study was to determine lower-limb range of motion (ROM) as a risk factor associated with sagittal spinal misalignments in children. Two hundred and one children (10.9 ± 0.7 years old) from five different primary schools were recruited for this retrospective case—control study. Anthropometric variables, sagittal spinal alignment in habitual everyday postures, and lower-limb ROM, such as ankle dorsiflexion with the knee flexed (ADF-KF), hip extension with the knee relaxed (HE), and hip flexion with the knee extended (HF-KE) were measured. Multivariate and univariate analyses revealed differences between the means of HE and HF-KE ROM, and the thoracic and lumbar curves (p ≤ 0.034; η2 ≥ 0.052). The HE (p ≤ 0.028; OR ≥ 1.066) predicted sagittal thoracic misalignment in the slump sitting (SSP) and relaxed standing (RSP) postures in males and the sagittal lumbar misalignment in the RSP in female children; while HF-KE (p ≤ 0.006; OR ≥ 1.089) predicted sagittal thoracic misalignment in the maximum trunk forward flexion posture (MTFP) and sagittal lumbar misalignment in SSP and MTFP in males. In this study, the reference values for restricted HE and HF-KE were significantly associated with sagittal spinal misalignment in male children but not for the ankle ROM. Physical education teachers should include stretching exercises in the ISQUIOS programme to increase the extensibility of the iliopsoas (HE) and hamstrings (HF-KE) and prevent sagittal spinal misalignments in habitual everyday postures.

A comparison of the reliability and vulnerability of 3D sterEOS and 2D EOS when measuring the sagittal spinal alignment of patients with adolescent idiopathic scoliosis.

An essential component of making the diagnosis of adolescent idiopathic scoliosis (AIS) is standing anteroposterior and lateral radiographs. Two-dimensional (2D) radiographs inevitably fail to reflect every plane of the three-dimensional (3D) deformity in scoliosis. We have tested the hypothesis that there is no difference in the assessment of the sagittal plane deformity when measured with either 2D or 3D EOS radiography. A retrospective radiographic analysis was performed on patients diagnosed with AIS, with subdivided into three groups according to the coronal angular deformity (mild group: 45°-69°, moderate group: 70°-89°, and severe group: 90° +). The sagittal parameters were compared between manual measurement with 2D sterEOS and those made using computer-aided 3D reconstruction. Fifty-two patients were included in each group. The inter-study reliability when measuring the thoracic Kyphosis (TK) and lumbar lordosis (LL) between the two study modalities was excellent in mild group (ICC: 0.90, 95% CI 0.82 ~ 0.94 and ICC: 0.84, 95% CI 0.74 ~ 0.91), excellent in TK and fair in LL in moderate group (ICC: 0.76, 95% CI 0.61 ~ 0.85 and ICC: 0.70, 95% CI 0.53 ~ 0.81), and fair in TK and LL in severe group, respectively (ICC: 0.74, 95% CI 0.57 ~ 0.84 and ICC: 0.65, 95% CI 0.46 ~ 0.84). A Bland-Altman plot showed proportional bias in TK measurements in each group and LL in moderate group, which means the measured value is underestimated in 2D method when the angle is small. 3D sterEOS is less vulnerable to the influence of coronal plane than 2D EOS in evaluating the sagittal spinal parameters of patients with a coronal deformity exceeding 70°.

Effects of the difference between lumbar lordosis in the supine and standing positions on the clinical outcomes of decompression surgery for lumbar spinal stenosis.

The authors sought to evaluate the relationship between the difference in lumbar lordosis (DiLL) in the preoperative supine and standing positions and spinal sagittal alignment in patients with lumbar spinal stenosis (LSS) and to determine whether this difference affects the clinical outcome of laminectomy. Sixty patients who underwent single-level unilateral laminectomy for bilateral decompression of LSS were evaluated. Spinopelvic parameters in the supine and standing positions were measured preoperatively and at 3 months and 2 years postoperatively. DiLL between the supine and standing positions was determined as follows: DiLL = supine LL - standing LL. On the basis of this determination patients were then categorized into DiLL(+) and DiLL(-) groups. The relationship between DiLL and preoperative spinopelvic parameters was evaluated using Pearson's correlation coefficient. In addition, clinical outcomes such as visual analog scale (VAS) and Oswestry Disability Index (ODI) scores between the two groups were measured, and their relationship to DiLL was evaluated using two-group comparison and multivariate analysis. There were 31 patients in the DiLL(+) group and 29 in the DiLL(-) group. DiLL was not associated with supine LL but was strongly correlated with standing LL and pelvic incidence (PI) - LL (PI - LL). In the preoperative spinopelvic alignment, LL and SS in the standing position were significantly smaller in the DiLL(+) group than in the DiLL(-) group, and PI - LL was significantly higher in the DiLL(+) group than in the DiLL(-) group. There was no difference in the clinical outcomes 3 months postoperatively, but low-back pain, especially in the sitting position, was significantly higher in the DiLL(+) group 2 years postoperatively. DiLL was associated with low-back pain in the sitting position, which was likely to persist in the DiLL(+) group postoperatively. We evaluated the relationship between DiLL and spinal sagittal alignment and the influence of DiLL on postoperative outcomes in patients with LSS. DiLL was strongly correlated with PI - LL, and in the DiLL(+) group, postoperative low-back pain relapsed. DiLL can be useful as a new spinal alignment evaluation method that supports the conventional spinal sagittal alignment evaluation.

Does Total Hip Arthroplasty Affect Spinopelvic and Spinal Alignment?: A Prospective Observational Investigation.

A prospective observational study, level of evidence 3. The study with patients undergoing unilateral total hip arthroplasty (THA) aimed to evaluate the following hypotheses: (1) the spinal sagittal and coronal alignment alters due to THA, (2) the spinopelvic parameter changes after THA, (3) the spinopelvic alignment differs between sagittal balanced and imbalanced patients. Surgical correction of spinal sagittal misalignment affects the spinopelvic alignment and pelvic tilt. It is not yet known to what extent THA affects spinopelvic, spinal sagittal, and coronal alignment. A total of 153 patients undergoing THA were assessed with biplanar stereoradiography in standing position preoperatively and postoperatively. Two independent investigators examined C7-sagittal vertical axis (C7-SVA), pelvic incidence-lumbar lordosis (PI-LL) mismatch, lumbar lordosis (LL), C7-central sacral vertical line, pelvic oblique angle lumbosacral, intra-pelvic oblique angle, pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), anterior plane pelvic tilt (APPT), and pelvic femoral angle (PFA). An analysis of the sagittal misaligned subgroups of C7-SVA and PI-LL on the influence of the spinopelvic alignment was performed. A significant difference in spinopelvic parameters was detected in the preoperative to postoperative comparison (SS, PT, APPT, and PFA; P &lt;0.000) ( d =-0.394; d =0.609; d =-0.481; d =0.431). The coronal alignment and pelvic obliquity revealed no significant differences. The misaligned groups (C7-SVA; PI-LL) demonstrated significant increases in PI and PT and decreased in LL compared with the groups with normal sagittal alignment. Preoperatively, 66/153 (C7-SVA) and 46/153 (PI-LL) of the THA patients presented sagittal misalignment, respectively. The results suggest an effect of THA on sagittal spinal and spinopelvic alignment, with a significant reduction of PT postoperatively and no effect on coronal alignment. Particularly striking are the significant differences in the misaligned groups, which may be classified as risk population and potentially can contribute biomechanically to a higher risk of posterior impingement and anterior THA dislocation. The substantial proportion of sagittal misaligned patients in the THA collective illustrates the crucial need for interdisciplinary collaboration.

The Impact of Upper Cervical Spine Alignment on Patient-reported Outcome Measures in Anterior Cervical Decompression and Fusion.

This was a retrospective cohort study. To determine the extent to which the upper cervical spine compensates for malalignment in the subaxial cervical spine, and how changes in upper cervical spine sagittal alignment affect patient-reported outcomes. Previous research has investigated the relationship between clinical outcomes and radiographic parameters in the subaxial cervical spine following anterior cervical discectomy and fusion (ACDF). However, limited research exists regarding the upper cervical spine (occiput to C2), which accounts for up to 40% of neck movement and has been hypothesized to compensate for subaxial dysfunction. Patients undergoing ACDF for cervical radiculopathy and/or myelopathy at a single center with minimum 1-year follow-up were included. Radiographic parameters including cervical sagittal vertical axis, C0 angle, C1 inclination angle, C2 slope, Occiput-C1 angle (Oc-C1 degrees), Oc-C2 degrees, Oc-C7 degrees, C1-C2 degrees, C1-C7 degrees, and C2-C7 degrees cervical lordosis (CL) were recorded preoperatively and postoperatively. Delta (Δ) values were calculated by subtracting preoperative values from postoperative values. Correlation analysis as well as multiple linear regression analysis was used to determine relationships between radiographic and clinical outcomes. Alpha was set at 0.05. A total of 264 patients were included (mean follow-up 20 mo). C2 slope significantly decreased for patients after surgery (Δ=-0.8, P =0.02), as did parameters of regional cervical lordosis (Oc-C7 degrees, C1-C7 degrees, and C2-C7 degrees; P <0.001, <0.001, and 0.01, respectively). Weak to moderate associations were observed between postoperative CL and C1 inclination ( r =-0.24, P <0.001), Oc-C1 degrees ( r =0.59, P <0.001), and C1-C2 degrees ( r =-0.23, P <0.001). Increased preoperative C1-C2 degrees and Oc-C2 degrees inversely correlated with preoperative SF-12 Mental Composite Score (MCS-12) scores ( r =-0.16, P =0.01 and r =-0.13, P =0.04). Cervical sagittal vertical axis was found to have weak but significant associations with Short Form-12 (SF-12) Physical Composite Score (PCS-12) ( r =-0.13, P =0.03) and MCS-12 ( r =0.12, P =0.05). No clinically significant relationship between upper cervical and subaxial cervical alignment was detected for patients undergoing ACDF for neurological symptoms. Upper cervical spine alignment was not found to be a significant predictor of patient-reported outcomes after ACDF. Level III.

Decreased muscle mass and strength affected spinal sagittal malalignment.

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. After excluding metal implant recipients, 1823 of 2551 patients (mean age: 69.2 ± 13.8years; 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. 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. 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.

Effect of Coronal and Sagittal Spinal Malalignment on Spinopelvic Mobility in Patients Undergoing Total Hip Replacement: A Prospective Observational Study.

This was a prospective observational study. This investigation aimed (1) to determine the impact of sagittal spinal alignment with C7-sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL) mismatch and Roussouly classification on individual segments of spinopelvic mobility represented by lumbar flexibility [∆lumbar lordosis (LL)], pelvic mobility [∆pelvic tilt (PT)], and hip motion [∆pelvic femoral angle (PFA)] and (2) to assess the influence of coronal spinal balance on the spinopelvic complex in patients undergoing total hip arthroplasty (THA) preoperatively and postoperatively. Restricted spinopelvic mobility gained attention as a contributing factor for THA instability. However, it remains unclear what influence the coronal and sagittal spinal alignment has on spinopelvic mobility. A total of 197 THA patients were included in the investigation conducting biplanar stereoradiography in standing and sitting position preoperatively and postoperatively. Two independent investigators assessed C7-SVA (≤50 mm balanced, >50 mm imbalanced), PI-LL (≤10 degrees balanced, >10 degrees imbalanced), refounded Roussouly classification, coronal spinal balance with C7-central sacral vertical line, LL, pelvic incidence (PI), PT, PFA. Individual segments of spinopelvic mobility based on the change from standing to sitting were defined as ∆LL, ∆PT, and ∆PFA. Unpaired t test or Welch t test for comparison between groups of 2 was applied. Analysis of variance and post hoc analysis according to Bonferroni or Games-Howell was used to determine differences between groups of >2. The Spearman rank correlation coefficient was used to determine the interrater reliability of the radiographic measurements. Significant differences were demonstrated for ∆LL (SVA balanced/imbalanced: 24.7 degrees/19.1 degrees, P =0.001; PI-LL balanced/imbalanced: 24.4 degrees/16.4 degrees, P <0.000), PT (SVA balanced/imbalanced: 12.5 degrees/15.2 degrees, P =0.029; PI-LL balanced/imbalanced: 10.8 degrees/20.5 degrees, P <0.000), PI (SVA balanced/imbalanced: 52.9 degrees/56.9 degrees, P =0.001; PI-LL balanced/imbalanced: 52.1 degrees/61.0 degrees, P <0.000), LL (SVA balanced/imbalanced: 54.8 degrees/47.8 degrees, P =0.029; PI-LL balanced/imbalanced: 55.3 degrees/42.6 degrees, P <0.000). The coronal spinal balance (central sacral vertical line) indicated no significant differences regarding spinopelvic mobility between positive, neutral, or negative balanced groups. Significant differences with decreased pelvic mobility (∆PT) and lumbar flexibility (∆LL) in low-grade PI types 1 and 2 compared with high-grade PI type 4 according to the Roussouly classification were observed. This is the first study to investigate spinal sagittal alignment using 3 different classifications in association to the spinopelvic complex in THA patients preoperatively and postoperatively. The significantly altered spinopelvic mechanics with decreased lumbar flexibility and increased pelvic retroversion in sagittal imbalanced patients clearly indicate the need for a separate consideration of the global spinal sagittal alignment. Our findings emphasize the importance of risk stratification for THA candidates in terms of sagittal imbalance attempting to mitigate the THA instability risk with accurate preoperative planning. Level III.

Assessment of clinical, imaging, surgical risk factors for subsequent fracture following vertebral augmentation in osteoporotic patients.

Currently, the risk factors for subsequent fracture following vertebral augmentation remain incomplete and controversial. To provide clinicians with accurate information for developing a preventive strategy, we carried out a comprehensive evaluation of previously controversial and unexplored risk factors. We retrospectively reviewed patients with osteoporotic vertebral compression fracture in lumbar spine who received vertebral augmentation between January 2019 and December 2020. Based on whether refracture occurred, patients were assigned to refracture and non-refracture group. The clinical characteristics, imaging parameters (severity of vertebral compression, spinal sagittal alignment, degeneration of paraspinal muscles), and surgical indicators (cement distribution and leakage, correction of spinal sagittal alignment) were collected and analyzed. There were 128 patients and 16 patients in non-refracture and refracture group. The incidence of previous fracture, multiple fractures, and cement leakage were notably higher, relative cross-sectional area of psoas (r-CSAPS) was significantly smaller, CSA ratio, fatty infiltration of erector spinae plus multifidus (FIES+MF), FIPS, postoperative lumbar lordosis (post-LL), correction of body angel (BA), and LL were significantly greater in refracture group. Binary logistic regression analysis revealed previous fracture, cement leakage, post-LL, and correction of BA were independent risk factors. According to the ROC curve, correction of BA showed the highest prediction accuracy, and the critical value was 3.45°. The occurrence of subsequent fracture might be the consequence of multiple factors. Previous fracture, cement leakage, post-LL, and correction of BA were identified as independent risk factors. Furthermore, the correction of BA should not exceed 3.45°, especially in patients with risk factors.

The challenge of measuring spinopelvic parameters: inter-rater reliability before and after minimally invasive lumbar spondylodesis

BackgroundThe common manual measurement technique of spinal sagittal alignment on X-rays is susceptible to rater-dependent variability, which has not been adequately considered in previous publications. This study investigates the effect of those variations in the characterization of patients receiving lumbar spondylodesis.MethodsGeneral alignment parameters on pre- and postoperative X-rays were evaluated by four raters in 43 prospectively sampled patients undergoing monolevel spondylodesis. The Intra-class Correlation Coefficient (ICC) for each rater pair and all raters together was calculated for inter-rater reliability. For the operation-induced change of the sagittal alignment in every patient the Wilcoxon test was applied to compare for each rater separately.ResultsThe ICCs were “good” (>0.75) to “excellent” (>0.9) for all raters together and for 45 of the 48 single rater pairs (93.75%). All revealed a significant increase of the addressed segmental lordosis and disc height and no significant change for spinopelvic parameters and sagittal vertical axis from pre- to postoperative. The lumbar lordosis showed a significant increase through the operation of +2.5° (p = 0.014) and +3.7° (p = 0.015) in two raters and no difference for the other ones (+2.1°, p = 0.171; -2.2°, p = 0.522).ConclusionsThe pre- to postoperative change of lumbar lordosis revealed different significance levels for different raters, although the ICCs were formally good. Accordingly, the evaluation by only one rater would lead to different conclusions. Due to this susceptibility of alignment measurements to rater-dependent variability, the exact evaluation process should be described in every publication and the consistency of significant results be validated through multiple raters.Trials registrationThe trial was approved by the local ethics committee and listed at the national clinical trials register (DRKS00004514, date of registration: 08/11/2012).

Comparison of the mass and amount of intramuscular non-contractile tissue of the trunk and lower extremity muscles between patients with Parkinson's disease and community-dwelling older adults.

This study compared the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles, sagittal spinal alignment, and mobility and balance ability between patients with Parkinson's disease (PD) and older adults. This study included 26 older adults (control [CTR] group) and eight patients with PD (PD group). Muscle thicknesses and echo intensities of the trunk and lower extremity muscles were measured using an ultrasound imaging device. Sagittal spinal alignments in the standing and prone positions were assessed using a Spinal Mouse. Mobility capacity was assessed based on the measurements of usual and maximal walking speeds, timed up-and-go (TUG) time, and five-chair-stand time, while balance ability was assessed based on the measurement of one-legged stance (OLS) time. Our results showed significantly lower gluteus maximus and tibialis anterior muscle thicknesses, higher thickness of the short head of the biceps femoris muscle, and higher echo intensity of the gluteus maximus muscle in the PD group than in the CTR group. Lumbar lordosis angle in the standing position, usual and maximal walking speeds, and OLS time were significantly lower, while the TUG and five-chair-stand times were significantly higher in the PD group than in the CTR group. The other factors did not differ significantly between groups. Our results revealed lower masses of the gluteus maximus and tibialis anterior muscles, higher mass of the short head of the biceps femoris muscle, and higher amounts of intramuscular non-contractile tissue of the gluteus maximus muscle in patients with PD.