Age-related variations in global spinal alignment and sagittal balance in asymptomatic Japanese adults

Influence of the type of atlantoaxial dislocation secondary to os odontoideum on sagittal alignment and balance of the subaxial cervical spine after posterior atlantoaxial fusion

OBJECTIVE

This retrospective study aims to investigate the effect of the type of atlantoaxial dislocation due to os odontoideum on the sagittal alignment and balance of the cervical spine after posterior atlantoaxial fusion.

METHODS

Data of 48 consecutive patients who underwent posterior C1-C2 fusion to treat atlantoaxial dislocation/instability due to os odontoideum were retrospectively reviewed. Radiographic variables, namely the T1 slope (T1S), C1-C2 angle, C2-C7 angle, C1-C2 sagittal vertical axis (SVA), C2-C7 SVA, and modified atlas-dens interval (MADI), were measured preoperatively, immediate postoperatively, and at final follow-up. Patients were divided into three groups based on the preoperative MADI. Differences within and between groups in radiographic variables and relationships between the investigated variables were analyzed.

RESULTS

The MADI was correlated with the preoperative to postoperative changes in the C1-C2 angle (r = 0.776, P < 0.05) and C2-C7 angle (r = - 0.357, P < 0.05). In the group with anterior atlantoaxial dislocation, the C1-C2 angle and C2-C7 SVA were significantly enlarged at final follow-up (P < 0.05), while the C2-C7 angle was significantly reduced (P < 0.05). The changes in C1-C2 angle and C2-C7 angle were opposite between the posterior group and the anterior dislocation group.

CONCLUSION

The direction/type of atlantoaxial subluxation correlates with the changes in lower cervical curvature after atlantoaxial fusion. Patients with atlantoaxial posterior dislocation and atlantoaxial instability are less likely than those with atlantoaxial anterior dislocation to develop loss of lordosis after posterior atlantoaxial fusion.

Correlation between sagittal parameters and disability of patients with nonspecific chronic low back pain: a cross-sectional study of 435 subjects

BACKGROUND CONTEXT

Sagittal parameters are significantly correlated with health-related quality of life (HRQoL) in adult spinal deformity patients. Their association with HRQoL in patients with nonspecific chronic low back pain (NSCLBP) is unclear.

PURPOSE

To analyze the correlation between sagittal parameters and disability in NSCLBP patients.

DESIGN

A cross-sectional study.

PATIENT SAMPLE

Subjects included 435 patients with NSCLBP divided into low disability and high disability groups.

OUTCOME MEASURES

Function was measured using the Oswestry Disability Index (ODI). Pain intensity was measured using the Numeric Rating Scale (NRS) and HRQoL was measured using 36-item Short Form Health Survey (SF-36).

METHODS

Sagittal parameters, demographic data, ODI, SF-36 eight-dimensional scores and NRS scores of patients with NSCLBP were collected. Taking ODI=20 as the cut-off value, patients were divided into low disability group (ODI≤20) and high disability group (ODI>20), and ODI were converted to Ranked ODI (RODI) accordingly. Univariate analysis of the correlation among age, gender, body mass index (BMI), sagittal parameters, RODI, SF-36 eight-dimensional scores, NRS scores were then conducted. The variables related to RODI were analyzed by logistic regression to discover their independent influence on RODI. p<.05 was considered to indicate statistical significance.

RESULTS

A total of 435 patients with NSCLBP were included. Univariate correlation analysis showed that the correlation coefficients between age, sacral slope-pelvic tilt (SS-PT), spinosacral angle (SSA) and RODI were (r=0.126, p<.01), (r=-0.115, p<.05), (r=-0.116, p<.05), respectively. The logistic regression analysis indicated that the regression coefficients of age and SSA were 0.030 (p=.001), -0.044 (p=.002), respectively, and the odds ratio and 95% confidence interval (CI) were 1.031 (1.012, 1.050), 0.957 (0.930, 0.985).

CONCLUSIONS

Age and SSA are independent factors for disability of NSCLBP. SSA can comprehensively reflect the sagittal balance of the spine of patients with NSCLBP. Decreased SSA represents poor sagittal balance, which will increase the disability of NSCLBP.

Do Postural and Walking Stabilities Change over a Decade by Aging? A Longitudinal Study

BACKGROUND

Previous studies have demonstrated that the center of gravity (COG) is more unstable in the elderly than in young people. However, it is unclear whether aging itself destabilizes the COG. This study aimed to investigate changes in COG sway and gait kinematics over time by a longitudinal study of middle-aged and elderly adults.

METHODS

This study included 198 healthy middle-aged and elderly people who underwent stabilometry at ten-year intervals. The participants' mean age at baseline was 62.9 ± 6.5 years, and 77 (39%) of them were male. The results of stabilometry (mean velocity, sway area, postural sway center in the medial-lateral direction [X center], and postural sway center in the anterior-posterior direction [Y center]), and results of exercise tests (the height-adjusted maximum stride length [HMSL] and the 10 m walk test [10MWT]) were analyzed. The destabilized group with 11 participants, whose mean velocity exceeded 3 cm/s after 10 years, was compared with the stable group with 187 participants, whose mean velocity did not exceed 3 cm/s.

RESULTS

Mean velocity increased significantly over ten years (open-eye, from 1.53 ± 0.42 cm to 1.86 ± 0.67 cm, p < 0.001); however, the sway area did not change significantly. X center showed no significant change, whereas Y center showed a significant negative shift (open-eye, from -1.03 ± 1.28 cm to -1.60 ± 1.56 cm, p < 0.001). Although the results of 10MWT and initial HMSL did not differ significantly, the HMSL in the destabilized group at ten years was 0.64, which was significantly smaller than the 0.72 of others (p = 0.019).

CONCLUSIONS

The ten-year changes in COG sway in middle-aged and elderly adults were characterized by a significant increase in mean velocity but no significant difference in sway area. Because the destabilized group had significantly smaller HMSL at ten years, instability at the onset of movement is likely to be affected by COG instability.

Prevalence of global spinal malalignment and the influence on LBP and HR-QOL in a healthy, nonelderly population. A cross sectional analysis, including bone mineral density, skeletal muscle mass index, and back muscle extensor strength

Background

In healthy, nonelderly populations, prevalence of 3 modifiers of global spinal malalignment (GS-MalAlign) (PT ≧20°, PI-LL≧10°, SVA≧40 mm) remains unknown. The clinical significance has not been determined. The purposes are to disclose the prevalence of the 3 modifiers of GS-MalAlign, and evaluate the influence on LBP, and HR-QOL related to bone mineral density (BMD), skeletal muscle mass index (SMI), and back muscle extensors strength (BMES) in a healthy, nonelderly population.

Methods

A mono-centric, cross-sectional survey. Three hundred and 2 participants (18< age <65 years) without ADL disturbance were consecutively enrolled. Sagittal parameters of the spine and the pelvis were measure on whole spine radiograms. BMD and SMI were determined using DEXA. BMES was defined as a maximum extension force at the T4 to T7 level and measured by a strain-gauge dynamotor. LBP was checked through interview. HR-QOL was ascertained by score of Medical Outcome Study Short-Form 36-Health Survey (SF-36v2).

Results

The final analysis could be done in 84 females and 179 males. PT≧20°, PI-LL≧10°, and SVA≧40 mm were found in 12% (31/263), 11% (31/263), and 6% (16/263), and each mean value was 25.0 ± 4.0°, 15.3 ± 5.9°, and 52.7 ± 12.2 mm (Mean ± S.D.). Prevalence of LBP was significantly higher in the participants with PI-LL≧10° than with PI-LL<10°; 43% (12/28) versus 21% (49/235) (p<.05). PI-LL≧10° only had an association with LBP (OR: 3.0435, 95% CI, 1.1378-8.141, p<.05). Four 2% of participants (4/263) associated with all 3 modifiers had LBP and a significantly lower mental component summary score of SF-36v2 (p<.05).

Conclusions

Some of individuals are associated with GS-MalAlign even in healthy, nonelderly populations. There is a possibility that PI-LL ≧10° results in LBP within a degree of no ADL disturbance, and it is speculated that coexistence of all 3 modifiers of GS-MalAlign would lead to a poor mental HR-QOL.

Prevalence and risk factors of occupational neck pain in Chinese male fighter pilots: a cross-sectional study based on questionnaire and cervical sagittal alignment

Background

Neck pain (NP) is a common musculoskeletal disorder among fighter pilots and has become a rising concern due to its detrimental impact on military combat effectiveness. The occurrence of NP is influenced by a variety of factors, but less attention has been paid to the association of NP with demographic, occupational, and cervical sagittal characteristics in this group. This study aimed to investigate the prevalence and risk factors of NP in Chinese male fighter pilots using a questionnaire and cervical sagittal measurements.

Methods

Demographic and flight-related data, as well as musculoskeletal pain information, were gathered from Chinese male fighter pilots via a self-report questionnaire. Cervical sagittal parameters were measured and subtypes were classified using standardized lateral cervical radiographs. Differences in various factors between the case and control groups were analyzed using t-tests or chi-square tests. Binary logistic regressions were conducted to explore potential risk factors contributing to NP. Predictors were presented as crude odds ratios (CORs) and adjusted odds ratios (AORs), along with their respective 95% confidence intervals (CIs).

Results

A total of 185 male fighter pilots were included in this cross-sectional study. Among them, 96 (51.9%) reported experiencing NP within the previous 12 months. The multivariate regression analysis revealed that continuous flight training (AOR: 4.695, 95% CI: 2.226-9.901, p < 0.001), shoulder pain (AOR: 11.891, 95% CI: 4.671-30.268, p < 0.001), and low back pain (AOR: 3.452, 95% CI: 1.600-7.446, p = 0.002) were significantly associated with NP.

Conclusion

The high 12-month prevalence of NP among Chinese male fighter pilots confirms the existence of this growing problem. Continuous flight training, shoulder pain, and low back pain have significant negative effects on pilots' neck health. Effective strategies are necessary to establish appropriate training schedules to reduce NP, and a more holistic perspective on musculoskeletal protection is needed. Given that spinal integrated balance and compensatory mechanisms may maintain individuals in a subclinical state, predicting the incidence of NP in fighter pilots based solely on sagittal characteristics in the cervical region may be inadequate.

Does locomotive syndrome severity predict future fragility fractures in community-dwelling women with osteoporosis?

OBJECTIVES

We investigated whether the locomotive syndrome (LS) severity affects future fragility fractures in osteoporosis patients.

METHODS

In this retrospective cohort study, 315 women with osteoporosis (mean follow-up period, 2.8 years) were reviewed, of whom 244 were included in the analysis. At baseline, we obtained medical information, bone mineral density of the lumbar spine and femoral neck, and sagittal vertical axis. Additionally, LS risk was assessed using the two-step test, stand-up test, and 25-question geriatric locomotive function scale scores. The LS risk test results were used to classify LS severity, which was rated on a 4-point scale from stage 0 (robust) to 3 (worsening). Cox proportional hazards regression analysis was used to determine the association of the severity with future fragility fracture.

RESULTS

Fragility fractures occurred in 37 of 315 participants (11.8%). This study showed that sagittal vertical axis (hazard ratio = 1.014; 95% confidence interval, 1.005-1.023; p value = 0.003) and LS severity (hazard ratio =1.748; 95% confidence interval, 1.133-2.699; p = 0.012) were independent risk factors for incidence of fragility fracture.

CONCLUSIONS

This study revealed the LS severity to predicted fragility fractures. We suggested that the progression of LS associated with osteoporosis increases the fracture risk.

The Relationship Between Cervical Sagittal Balance and Type of Atlantoaxial Dislocation Secondary to Os Odontoideum

OBJECTIVE

To analyze the effect of cervical sagittal balance on the direction and type of atlantoaxial dislocation.

METHODS

Data of 55 patients seen at our hospital for atlantoaxial instability/dislocation caused by os odontoideum were reviewed. Radiographic variables, including T1 slope (T1S), C1-C2 angle, C2-C7 angle, C1-C2 sagittal vertical axis (SVA), C2-C7 SVA, and atlanto-dens interval (ADI), were measured preoperatively. Patients were divided into three groups according to ADI: anterior atlantoaxial dislocation, atlantoaxial instability, and posterior atlantoaxial dislocation. Differences within and between groups in radiographic variables and relationships between the investigated variables were analyzed.

RESULTS

ADI was strongly negatively associated with C1-C2 angle (r = -0.805, P < 0.05); whereas ADI had a medium-strength positive relationship with C2-C7 angle (r = 0.425, P < 0.05) and a medium-strength negative relationship with C2-C7 SVA (r = -0.411, P < 0.05). However, ADI was not significantly correlated with T1 slope (r = -0.092, P > 0.05).

CONCLUSIONS

The type and direction of atlantoaxial dislocation is closely associated with cervical sagittal balance. C2-C7 SVA is an important factor in assessing the direction of atlantoaxial subluxation secondary to os odontoideum. ADI decreases with increasing C2-C7 SVA. The larger the C2-C7 SVA, the more likely the atlantoaxial dislocation is to be posterior.

Cervical Sagittal Alignment and Balance Associated With Aging Chinese Adults: A Radiographic Analysis

STUDY DESIGN

This was a retrospective cohort radiographic study.

OBJECTIVE

To determine the age- and gender-related normative values and correlation of cervical sagittal parameters in asymptomatic Chinese adults, and to explore the changes and compensating mechanisms across different age groups.

METHODS

The asymptomatic subjects were divided into 6 groups according to age and then one-way analysis of variance was used to compare the multiple sets of cervical sagittal parameters among the different age groups. Independent t-tests were performed to compare the sagittal parameters among different gender and different cervical spine alignments. Relationships between each parameter were tested by Pearson's correlation. Linear regression analysis based on T1 slope (T1S) and C2 slope (C2S) was used to provide an equation to predict normal cervical alignment.

RESULTS

Mean values of each cervical sagittal parameter were presented based on age and gender. There were positive correlations between age and cervical lordosis (CL) (r = -.278, P < .001), T1S (r = .271, P < .001), cervical sagittal vertical axis (cSVA) (r = .218, P < .001), C2-C4 Cobb angle (r = -.283, P < .001), horacic inlet angle (TIA) (r = .443, P < .001), and neck tilt (NT) (r = .354, P < .001). Older groups (aged >50 years) had greater T1 Slope, C2S, and TIA. The C2-C4 Cobb angle maintained a steadily increasing trend and significantly increased in the older adult groups (P < .05), while the C5-C7 Cobb angle was relatively constant. Mean values of parameters were larger in males (P > .05). Linear regression analysis indicated a strong association between T1S and CL (R2 = .551, standard error 1.16°), T1S and C5-7 (R2 = .372; P < .001), and C2S and C2-4 (R2 = .309; P < .001).

CONCLUSIONS

Normative values of cervical sagittal parameters vary by age and sex. The CL, cSVA, and T1S, C2-4 Cobb angle changed with increasing age, and it can influence the recruitment of compensation mechanism. Normative CL of Chinese adults was predicted by the equation CL = T1S-14.7° ± 1.2°, which could serve as a reference when planning for cervical surgery.

The effect of ethnicity on the age-related changes of spinopelvic characteristics: a systematic review

Aims

Spinopelvic characteristics influence the hip’s biomechanical behaviour. However, to date there is little knowledge defining what ‘normal’ spinopelvic characteristics are. This study aims to determine how static spinopelvic characteristics change with age and ethnicity among asymptomatic, healthy individuals.

Methods

This systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines to identify English studies, including ≥ 18-year-old participants, without evidence of hip or spine pathology or a history of previous surgery or interventional treatment, documenting lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). From a total of 2,543 articles retrieved after the initial database search, 61 articles were eventually selected for data extraction.

Results

When all ethnicities were combined the mean values for LL, SS, PT, and PI were: 47.4° (SD 11.0°), 35.8° (SD 7.8°), 14.0° (SD 7.2°), and 48.8° (SD 10°), respectively. LL, SS, and PT had statistically significant (p < 0.001) changes per decade at: −1.5° (SD 0.3°), −1.3° (SD 0.3°), and 1.4° (SD 0.1°). Asian populations had the largest age-dependent change in LL, SS, and PT compared to any other ethnicity per decade at: −1.3° (SD 0.3°) to −0.5° (SD 1.3°), –1.2° (SD 0.2°) to −0.3° (SD 0.3°), and 1.7° (SD 0.2°) versus 1.1° (SD 0.1°), respectively.

Conclusion

Ageing alters the orientation between the spine and pelvis, causing LL, SS, and PT to modify their orientations in a compensatory mechanism to maintain sagittal alignment for balance when standing. Asian populations have the largest degree of age-dependent change to their spinopelvic parameters compared to any other ethnicity, likely due to their lower PI.

Cite this article: Bone Joint Res 2023;12(4):231–244.

Sagittal alignment cut-off values for predicting future fall-related fractures in community-dwelling osteoporotic women

PURPOSE

Determining the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures is essential for understanding fracture risk and informing clinicians and physical therapists. We determined the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures in this study.

METHODS

In the retrospective cohort study, we enrolled a total of 255 women aged ≥ 65 years who visited an outpatient osteoporosis clinic. We measured participants' bone mineral density and sagittal alignment, including sagittal vertical axis (SVA), pelvic tilt, thoracic kyphosis, pelvic incidence, lumbar lordosis, global tilt, and gap score at the initial visit. The cut-off value for sagittal alignment that was significantly associated with fall-related fractures was calculated after using multivariate Cox proportional hazards regression analysis.

RESULTS

Ultimately, 192 patients were included in the analysis. After a mean follow-up of 3.0 years, 12.0% (n = 23) had fractures due to falls. Multivariate Cox regression analysis confirmed that SVA (hazard ratio [HR] = 1.022, 95% confidence interval [CI] = 1.005-1.039) was the only independent predictor of fall-related fracture occurrence. The predictive ability of SVA for the occurrence of fall-related fractures was moderate (area under the curve [AUC] = 0.728, 95% CI = 0.623-0.834), with a cut-off value of 100 mm for SVA. SVA classified by cut-off value was also associated with an increased risk of developing fall-related fractures (HR = 17.002, 95% CI = 4.102-70.475).

CONCLUSION

We found that assessing the cut-off value of sagittal alignment would be useful information in understanding fracture risk in postmenopausal older women.

Sagittal alignment cut-off values for predicting future fall-related fractures in community-dwelling osteoporotic women

PURPOSE

Determining the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures is essential for understanding fracture risk and informing clinicians and physical therapists. We determined the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures in this study.

METHODS

In the retrospective cohort study, we enrolled a total of 255 women aged ≥ 65 years who visited an outpatient osteoporosis clinic. We measured participants' bone mineral density and sagittal alignment, including sagittal vertical axis (SVA), pelvic tilt, thoracic kyphosis, pelvic incidence, lumbar lordosis, global tilt, and gap score at the initial visit. The cut-off value for sagittal alignment that was significantly associated with fall-related fractures was calculated after using multivariate Cox proportional hazards regression analysis.

RESULTS

Ultimately, 192 patients were included in the analysis. After a mean follow-up of 3.0 years, 12.0% (n = 23) had fractures due to falls. Multivariate Cox regression analysis confirmed that SVA (hazard ratio [HR] = 1.022, 95% confidence interval [CI] = 1.005-1.039) was the only independent predictor of fall-related fracture occurrence. The predictive ability of SVA for the occurrence of fall-related fractures was moderate (area under the curve [AUC] = 0.728, 95% CI = 0.623-0.834), with a cut-off value of 100 mm for SVA. SVA classified by cut-off value was also associated with an increased risk of developing fall-related fractures (HR = 17.002, 95% CI = 4.102-70.475).

CONCLUSION

We found that assessing the cut-off value of sagittal alignment would be useful information in understanding fracture risk in postmenopausal older women.

Outcome of Anterior and Posterior Endoscopic Procedures for Cervical Radiculopathy Due to Degenerative Disk Disease: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

Cervical spine endoscopic discectomy and decompression have gained popularity in the last decade. This review aimed to shed light on the current outcomes of cervical spine endoscopic procedures for degenerative disc disease (DDD) and to calculate a pooled estimate of various outcome measures.

METHODS

We retrieved articles published in English related to endoscopic cervical spine procedures from 3 central databases from inception until September 2020. A subgroup analysis based on the anterior versus the posterior approach was performed.

RESULTS

Thirty-one articles fulfilled the eligibility criteria and included 1,410 patients. A successful outcome was observed in 91.3% (88.6-93.4%, P = 0.000). This percentage was lower for the anterior approach (89.6% [85.8-92.5%], P = 0.000) than for the posterior approach (94.2% [90.4-96.5%], P = 0.000). A higher percentage of poor outcomes was reported for the anterior approach (5.7% [3.2-10.1%], P = 0.000 vs. 2.3% [1-5.5%], P = 0.000 for the posterior approach). The overall complication rate was 7.2% (5.2-9.8%, P = 0.000). There was a slightly higher complication rate for the anterior approach (7.9% [4.5-13.3%], P = 0.000) than for the posterior approach (6.7% [4.4-10%], P = 0.000). The revision rate was 4.2% (2.6-6.8%, P = 0.000); and 4.2% (1.8-9.7%, P = 0.000) for the anterior approach and 4.00% (2.2-7.4%, P = 0.000) for the posterior approach.

CONCLUSIONS

There is a higher success rate and lower complication rate with the posterior approach than with the anterior approach. However, high-quality randomized controlled trials are vital to evaluate the efficacy of these procedures.

Association with sagittal alignment and osteoporosis-related fractures in outpatient women with osteoporosis

The baseline sagittal vertical axis (SVA) and pelvic tilt (PT) are independent risk factors of osteoporosis-related fractures in women with osteoporosis. We clarified the SVA and PT to predict the incidence of osteoporosis-related fractures.

PURPOSE

Sagittal alignment with osteoporosis women deteriorates with advancing age and sagittal alignment may indicate osteoporosis-related fractures in the future. However, whether the sagittal alignment predicts future osteoporosis-related fracture in patients with osteoporosis has not been clarified. We aimed to investigate the association between sagittal alignment and future osteoporosis-related fractures.

METHODS

This was a retrospective cohort study. Of the 313 participants (mean follow-up period, 2.9 years), 236 were included in the analysis. At baseline, we measured bone mineral density (BMD) of the lumbar spine and the femoral neck, sagittal vertical axis (SVA), thoracic kyphosis, pelvic incidence minus lumbar lordosis, sacral slope, pelvic tilt (PT), geriatric locomotive function scale (GLFS), two-step value, and stand-up test. The information on medications and the duration of treatment were reviewed from the medical records. Additionally, participants reported their history of falls at baseline. Multiple logistic regression analysis was used to determine the association of future osteoporosis-related fracture, and adjusted Odds ratios (OR) and 95% confidence interval (CI) were calculated with all predictors as covariates. All continuous variables were calculated using standardized OR (sOR).

RESULTS

Osteoporosis-related fractures occurred in 33 of 313 participants (10.5%). Multiple logistic regression analysis showed that a history of falls (OR =4.092, 95% CI: 1.029-16.265, p =0.045), SVA (sOR =4.228, 95% CI: 2.118-8.439, p <0.001), and PT (sOR =2.497, 95% CI: 1.087-5.733, p =0.031) were independent risk factors for future osteoporosis-related fractures.

CONCLUSIONS

This study revealed the SVA and PT to predict osteoporosis-related fractures.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

UMIN000036516 (April 1, 2019).

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.

Predictors of Spontaneous Restoration of Lumbar Lordosis after Single-Level Transforaminal Lumbar Interbody Fusion for Degenerative Lumbar Diseases

Introduction

Preoperative factors that predict postoperative restoration of lumbar lordosis (LL) are not well understood. To investigate whether preoperative postural correction of LL, sagittal malalignment, or lumbar flexibility are associated with the postoperative restoration of LL in patients treated with a single-level transforaminal lumbar interbody fusion (TLIF), a retrospective cohort study was conducted.

Methods

We enrolled 104 patients (mean age: 67.5±10.7 years old; 47 men and 57 women) with lumbar degenerative diseases treated with a single-level TLIF. The pre- and postoperative LL were examined using lateral radiographs in the standing position and computed tomography (CT) images in the supine position. The correlation between postoperative LL restoration and preoperative postural correction of LL (difference in LL between the standing and supine positions: D-LL), sagittal imbalance (pelvic incidence minus LL: PI-LL), and lumbar flexibility (difference in LL between the flexion and extension postures) were analyzed. Patients were divided into two groups according to the D-LL (D-LL≥0° and D-LL<0°). The rates of postoperative LL restoration (postoperative LL-preoperative LL in standing) were compared between the two groups.

Results

Multiple regression analysis performed after adjustment for age, gender, body mass index, and cage angle revealed that postoperative LL restoration was significantly correlated with D-LL (p<0.001), but not with PI-LL, and lumbar flexibility. Patients with a preoperative D-LL≥0° showed a significantly greater increase of LL after TLIF (7.1°±11.2°) than those with D-LL<0° (1.4°±6.6°) (p=0.003).

Conclusions

A preoperative evaluation of a lateral radiograph or CT taken in the supine position is useful in predicting postoperative improvement of sagittal alignment. Postoperative improvement of sagittal spinopelvic alignment would be expected when LL is corrected in the supine position preoperatively. Surgeons should pay attention to the postural correction of LL when performing short-segment fusion surgery for lumbar degenerative disease with sagittal malalignment.

Magnetic Resonance Imaging of the Cervical Spine: Frequency of Abnormal Findings with Relation to Age

Background: Patients with neck pain are frequently encountered in cervical spine (C-spine) magnetic resonance imaging (MRI) practice. However, the exact distribution and prevalence of cervical abnormalities are not known. Aim: The aim of this study is to evaluate the association between age, gender, and prevalence of abnormal cervical MRI findings. Methods: Records of 111 cervical MRIs were collected in 12 months from January to December 2019 from adults aged 20–89 years who were referred from neurosurgery, neurology, and orthopedic clinics. Findings were classified and analyzed using the Statistical Package for Social Science (SPSS), version 24.0 (IBM, Armonk, NY, USA). The chi-square test was used to determine the association between demographics and abnormalities using a significance of p = 0.05. Results: The majority of patients were female (72.1%). The number of abnormal incidences increased with age until it reached a peak at ages 50–59. Spondylodegenerative changes were the most frequent finding, which was present in 52.2% of the total sample, and was followed by disc bulge (25.2%). Incidences increased in lower discs, with C5–C6 being the most frequent in 65% of the total sample. Younger males in their 20s had more injuries than females of the same age. However, this rate was reversed in patients over 40, as women were the dominant gender among patients in their 40s with cervical injuries, with a rate of 81.5%. Conclusion: In our study, we found that older patients developed more C-spine injuries. Gender may play a role in the rate of incidents. However, we did not find any significant differences between men and women or between different types of abnormalities.

The Influence of Nordic Walking on Spinal Posture, Physical Function, and Back Pain in Community-Dwelling Older Adults: A Pilot Study

Nordic walking is an increasingly popular form of exercise among the elderly. Using poles is thought to facilitate a more upright posture; however, previous studies primarily investigated the effects of Nordic walking on respiratory function and physical fitness. The aims of this study were to investigate the influence of Nordic walking on spinal posture, physical functions, and back pain in community-dwelling older adults. Thirty-one community-dwelling older adults aged ≥ 60 years participated in a twice weekly Nordic walking training program for 12 weeks. The outcome measures, including spinal posture, physical functions, back pain, and the strength and endurance of back extensor muscles were assessed before and after a 12-week program. After training, spinal posture, back pain, and the strength and endurance of back extensor muscles did not show any statistically significant changes. Among the seven clinical tests of physical function, only the 30 s arm curl test, the 30 s chair stand test, and the single leg stance test showed significant improvements. Nordic walking has limited influence on age-related hyperkyphosis and back pain, but may be effective for physical function. The results of this study can provide useful information for people involved in the prevention and treatment of physical dysfunction in community-dwelling older adults.

Computed Tomographic Assessment of Age- and Gender-Specific Sagittal Lumbopelvic Alignment in a Japanese Population

Introduction

Previous studies have reported differences in lumbopelvic alignment between standing and supine positions. Computed tomography (CT) images taken in the supine position are often used for clinical studies in addition to standing radiographs, although not frequently. Our study aims to clarify normative values of CT-evaluated lumbopelvic parameters and the characteristics of age- and gender-related lumbopelvic alignment in the supine position.

Methods

Patients undergoing CT scans of abdominal or lumbar regions for reasons other than low back disorders were included (n=581). Sagittal multiplanar reconstruction CT images were obtained, and lumbar lordosis (LL), L5-S1 angle, and sacral slope (SS) were measured. Mean values of the parameters in patients aged 59 years and under, 60-69, 70-79, and 80 and over, and in males and females, were calculated. Age- and gender-related differences in these parameters were statistically analyzed.

Results

Among the four age groups, patients 80 years and over showed significantly lower LL and SS than patients aged 70-79. Females 80 years and over showed significantly lower LL and SS than all other age groups, but those in males did not. The comparison between males and females showed no significant differences in LL and SS; however, the L5-S1 angle was significantly higher in males than in females. In patients 80 years and over, females showed significantly lower LL and SS than in males.

Conclusions

This study provides normative CT-evaluated lumbopelvic parameters, such as LL, L5-S1 angle, and SS, which will be utilized for comparisons in future studies. The present study first revealed that pelvic retroversion and lumbar kyphosis occur in elderly females in the supine position, which raised a possibility that age-related decrease of LL and SS in females occurs at an older age in the supine position than in the standing position.

The impact of age, sex, disc height loss and T1 slope on the upper and lower cervical lordosis: a large-scale radiologic study

PURPOSE

To clarify the relative influence of age, sex, disc height loss and T1 slope on upper (Occiput-C2) and lower cervical lordosis (C2-C7).

METHODS

Standing lateral cervical radiographs of 865 adult subjects were evaluated. The presence and severity of disc height loss from C2/C3 to C6/C7 (a total of 4325 discs) were assessed using a validated grading system. The total disc height loss score for each subject was calculated as the sum of the score of each disc space. Sagittal radiographic parameters included: occipital slope, occiput-C2 (Oc-C2) lordosis, C2-C7 lordosis and T1 slope. Multivariable regression analyses were performed to examine the relative influence of the multiple factors on upper and lower cervical lordosis.

RESULTS

This study included 360 males and 505 females, with a mean age of 40.2 ± 16.0 years (range, 20-95 years). Linear multivariate regression analyses showed that greater age, male sex, greater T1 slope were each found to be significantly and independently associated with greater C2-C7 lordosis, whereas total disc height loss score was negatively associated with C2-C7 lordosis. T1 slope had the most independent influence on C2-C7 lordosis among these factors. Age, sex and disc height loss were not independently associated with Oc-C2 lordosis.

CONCLUSIONS

Results from our large-scale radiologic analysis may enhance the understanding of the factors that affect cervical lordosis, indicating that age, sex, disc height loss and T1 slope were each independently associated with C2-C7 lordosis. However, age, sex and disc height loss were not independently associated with upper cervical lordosis.

Global Sagittal Balance of Spine in Asymptomatic Controls: A Systematic Review and Meta-Analysis

OBJECTIVE

To assess the global sagittal balance of spine (GSBS) in asymptomatic controls.

METHODS

PubMed, Scopus, Cochrane library, and Web of Science searched up to July 2020. Studies were screened for the GSB parameters including T1 pelvic angle (TPA), spinosacral angle (SSA), sagittal vertical axis (SVA), C7/sacrofemoral distance ratio (Barrey index), odontoid hip axis (OD-HA), and Full Balance Index (FBI) as measured in asymptomatic participants. A meta-analysis was performed to synthesize pooled estimates. Heterogeneity and publication bias were assessed.

RESULTS

Overall, 76 studies were identified including 12,169 participants (54.7% female) with mean age ranges from 12.0 to 72.9 years old. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of studies included in this review. Begg's test did not indicate obvious publication bias. The pooled analysis reveals that the mean (standard deviation) normative values were: 1) age ˃18 years, SSA (°), 127.6 (0.89); SVA absolute value (millimeters), 13.1 (1.13); TPA (°), 9.8 (1.13); T1SPI (°), -4.3 (0.57); and Barrey index absolute value, 0.51 (0.3). The mean value of the OD-HA (°) was reported 2.9 (1.6), and the FBI average value was less than 5°. 2) Age ≤18 years, SSA (°), 132.1 (8.3); SVA absolute value (millimeters), 11.9 (2.0); and Barrey index, -0.7 (8.3). A significant difference was observed between the 2 age groups based on SVA and SSA.

CONCLUSIONS

This paper presents normative data on TPA, SSA, SVA, Barrey index, OD-HA, and FBI as a reference for evaluating/measuring a GSB of spine in asymptomatic controls.

The relationship between thoracic kyphosis and age, and normative values across age groups: a systematic review of healthy adults

Background

Thoracic kyphosis is reported to increase with ageing. However, this relationship has not been systematically investigated. Peoples’ kyphosis often exceeds 40°, but 40° is the widely accepted cut-off and threshold for normality. Consequently, patients may be misclassified. Accurate restoration of kyphosis is important to avoid complications following spinal surgery. Therefore, specific reference values are needed. The objective of the review is to explore the relationship between thoracic kyphosis and age, provide normative values of kyphosis for different age groups and investigate the influence of gender and ethnicity.

Methods

Two reviewers independently conducted a literature search, including seven databases and the Spine Journal, from inception to April 2020. Quantitative observational studies on healthy adults (18 years of age or older) with no known pathologies, and measuring kyphosis with Cobb’s method, a flexicurve, or a kyphometer, were included. Study selection, data extraction, and study quality assessment (AQUA tool) were performed independently by two reviewers. The authors were contacted if clarifications were necessary. Correlation analysis and inferential statistics were performed (Microsoft Excel). The results are presented narratively. A modified GRADE was used for evidence quality assessment.

Results

Thirty-four studies (24 moderate-quality, 10 high-quality) were included (n = 7633). A positive moderate correlation between kyphosis and age was found (Spearman 0.52, p < 0.05, T5-T12). Peoples’ kyphosis resulted greater than 40° in 65% of the cases, and it was significantly smaller in individuals younger than 40 years old (x < 40) than in those older than 60 years old (x > 60) 75% of the time (p < 0.05). No differences between genders were found, although a greater kyphosis angle was observed in North Americans and Europeans.

Conclusion

Kyphosis increases with ageing, varying significantly between x < 40 and x > 60. Furthermore, kyphosis appears to be influenced by ethnicity, but not gender. Peoples’ thoracic sagittal curvature frequently exceeds 40°.

Trial registration

The review protocol was devised following the PRISMA-P Guidelines, and it was registered on PROSPERO (CRD42020175058) before study commencement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02592-2.

Normal spino-pelvic parameters and correlation between lumbar lordosis (LL) and pelvic incidence (PI) in children and adolescents in Indian population

PURPOSE

The purpose of this work is to describe normal spino-pelvic parameters for pediatric and adolescent Indian population (and compare it with a cohort of different ethnicity) and to find out the correlation of pelvis incidence (PI) and lumbar lordosis (LL) METHODS: 129 asymptomatic subjects (66 males, 63 females) with age 4-15 years were studied. Pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and lumbar lordosis (LL) were measured on lateral whole-spine standing radiographs using computer software and compared in relation to age, sex, and ethnicity. Using correlation and regression analysis, the association and predictability of LL with PI was studied within the entire sample and then among age groups 4-10 and 11-15 years.

RESULTS

Mean PI was 42° ± 8.1°, whereas PT and SS were 12.9° ± 7.8° and 29.3° ± 9.62°, respectively. PI and SS were lower (p < 0.0001), but PT was higher than Caucasians. Overall PI remained unchanged in the age group > 10 years in comparison to the younger age. Mean PT was lower (p = 0.0020), but SS and LL were higher (p = 0.0027 and p = 0.0002 respectively). Angular spino-pelvic parameters were similar between sex groups. Overall correlation between PI and LL was 0.4 (p < 0.0001) which was 0.1 (p = 0.2345) and 0.5 (p < 0.0001) for ages 4-10 and 11-15 years, respectively. Overall, the prediction of PI based on LL is not very accurate with a simple linear term between PI and LL (R² = 0.1) and only improve marginally with a restricted cubic spline function.

CONCLUSIONS

In pediatric and adolescent' population, ethnicity and age-related variations of normal sagittal spino-pelvic parameters exist and should be considered in patient management.

Radiographic Analysis of the Sagittal Alignment of Spine and Pelvis in Asymptomatic Indian Population

Study Design

This is a descriptive observational study.

Purpose

The objective of this study is to analyze and document the sagittal alignment of the spine and pelvis in normal Indian adult volunteers and compare these parameters with the study population of other races and ethnicities.

Overview of Literature

Given the importance of the spinopelvic parameters, there is a need to describe the parameters differentially in relation to the ethnicity of the studied individual. Very few reports have defined the normal physiological value. Ethnic differences are a significant factor not only when describing the anthropometric data but also when applying the findings to a different ethnic group. We have compared these values with other races and ethnicities so that we can know whether the principles of spinal fixation can be applied globally.

Methods

In total, 100 participants were studied by using their anteroposterior and lateral radiographic images of whole of pelvic and spinal area. Additionally, various spinal and pelvic parameters were also measured. Subsequently, the outcomes were analyzed with respect to age, sex, and body mass index (BMI). The correlation between different parameters and differences in these parameters between Indians and other races/ethnicities along with population groups were also analyzed.

Results

There was a significant increase in thoracic kyphosis (TK) from T1–T12 and T4–T12 with increasing age. Lumbar lordosis (LL), sacral translation (sagittal vertical axis), and pelvic tilt were significantly higher among females. Additionally, sacral slope (SS), pelvic incidence, C7 sagittal offset, and T9 sagittal offset were also higher in females. TK (T4–T12 and T1–T12), LL, SS, and pelvic incidence showed a significant correlation with BMI. As compared to European population, TK, segmental LL, and sacral translation were found to be significantly lesser in Indian population.

Conclusions

There is a statistically significant difference between Indians and other races/ethnicities and population groups with respect to TK, LL, and sacral translation. The values obtained can be considered as the physiological normal values for Indian population. Importantly, these values can serve as the reference values for future studies.

Sagittal balance of the cervical spine: a systematic review and meta-analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the cervical sagittal parameters between patients with cervical spine disorder and asymptomatic controls.

METHODS

Two independent authors systematically searched online databases including Pubmed, Scopus, Cochrane library, and Web of Science up to June 2020. Cervical sagittal balance parameters, such as T1 slope, cervical SVA (cSVA), and spine cranial angle (SCA), were compared between the cervical spine in healthy, symptomatic, and pre-operative participants. Where possible, we pooled data using random-effects meta-analysis, by CMA software. Heterogeneity and publication bias were assessed using the I-squared statistic and funnel plots, respectively.

RESULTS

A total of 102 studies, comprising 13,802 cases (52.7% female), were included in this meta-analysis. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of studies included in this review. Funnel plot and Begg's test did not indicate obvious publication bias. The pooled analysis reveals that the mean (SD) values were: T1 slope (degree), 24.5 (0.98), 25.7 (0.99), 25.4 (0.34); cSVA (mm), 18.7 (1.76), 22.7 (0.66), 22.4 (0.68) for healthy population, symptomatic, and pre-operative assessment, respectively. The mean value of the SCA (degree) was 79.5 (3.55) and 75.6 (10.3) for healthy and symptomatic groups, respectively. Statistical differences were observed between the groups (all P values < 0.001).

CONCLUSION

The findings showed that the T1 slope and the cSVA were significantly lower among patients with cervical spine disorder compared to controls and higher for the SCA. Further well-conducted studies are needed to complement our findings.

Optimal indicators for identification of compensatory sagittal balance in patients with degenerative disc disease

Study design

A retrospective study.

Background

To determine whether radiological parameters such as maximal lumbar lordosis-maximal thoracic kyphosis (maxLL-maxTK), sacral slope-pelvic tilt(SS-PT) and sacral slope/pelvic tilt (SS/PT) could be used as indicators for the diagnosis of degenerative disc disease (DDD) in compensatory sagittal balanced patients.

Methods

Medical records of sagittal balanced DDD patients and asymptomatic adults within our hospital registry from July 2019 to November 2019 were reviewed. General characteristics and radiological parameters were evaluated between the two groups. Analysis of covariance with age as a covariate was conducted, followed by receiver operating characteristic (ROC) analysis and areas under the curve (AUC) calculation. The max Youden index was calculated to identify the optimal sensitivity specificity pairs.

Results

A total of 42 DDD patients and 199 asymptomatic adults were included. For those parameters that showed significant differences between the two groups, AUC for SS/PT and SS-PT were the largest, reaching 0.919 and 0.936, respectively. The sensitivity was 0.749, the specificity was 0.952 and the max Youden index was 0.701 when SS/PT = 1.635 was used as threshold. The max Youden index was found for a threshold of SS-PT =8.500, for which the sensitivity increased to 0.854, while the specificity decreased to 0.857.

Conclusions

Both SS/PT and SS-PT were significantly different between sagittal balanced DDD patients and asymptomatic adults. SS/PT < 1.6 and SS-PT < 8.5 could be used as indicators for the diagnosis of DDD patients with compensatory sagittal balance.

Lumbar lordosis morphology correlates to pelvic incidence and erector spinae muscularity

The retrospective study aimed to investigate the relationship between lumbar lordosis morphology, pelvic incidence and paraspinal muscle. It enrolled asymptomatic adult volunteers aged between 18 and 45 years old. Lumbar lordosis morphology, consisting of total lumbar lordosis (LL), proximal lumbar lordosis (PLL), distal lumbar lordosis (DLL), lumbar lordosis apex (LLA) and inflexion point, was evaluated, as well as pelvic incidence (PI) and muscularity of erector spinae (ES) and multifidus. Pearson correlation was performed to analyze the relationship between each other parameter. Cases were stratified according to pelvic incidence (very low < 30°, low 30°–45°, moderate 45°–60°, and high > 60°), comparison between groups was performed by univariance analysis. 87 asymptomatic adult volunteers (33 females and 54 males) were included in the study. PLL revealed a correlation with LLA (r = 0.603, p = 0.002) and inflexion point (r = 0.536, p = 0.004), but did not DLL with LL apex (r = 0.204, p = 0.058) or inflexion point (r = 0.210, p = 0.051). PI revealed a greater correlation with PLL (r = −0.673, p < 0.001) than with DLL (r = −0.237, p = 0.045). Linear stepwise regression analysis also exhibited the correlation between PI and PLL (R² = 0.452, PLL = 16.2–0.61 * PI, p < 0.001). ES muscularity correlated with LL apex (r = −0.279, p = 0.014) and inflexion point (r = −0.227, p = 0.047). Stratification by PI demonstrated PLL increased across groups (p < 0.001), but DLL was comparable between low and moderate PI group (p = 0.329). Lumbar lordosis morphology appears to accommodate to pelvic incidence and erector spinae muscularity. Proximal lumbar lordosis has a bigger correlation with pelvic incidence than the distal lumbar lordosis. The results are helpful for restoring a rational lumbar lordosis shape in long fusion surgery.

Correlations and Age-Related Changes of Cervical Sagittal Parameters in Adults Without Symptoms of Cervical Spinal Disease

STUDY DESIGN

Retrospective study.

OBJECTIVE

To determine the correlations and age-related changes of cervical sagittal parameters in adults without obvious cervical spinal disease.

SUMMARY OF BACKGROUND DATA

Cervical sagittal parameters play essential roles in the pathogenesis and therapy of cervical spinal diseases. However, few studies have investigated the correlations and age-related changes of cervical sagittal parameters.

METHODS

The enrolled participants were divided into three age groups and their cervical sagittal parameters were collected. Correlations and age-related changes of these parameters were analyzed.

RESULTS

Significant differences in the C2-C7 angle, center of gravity of the head-C7 sagittal vertical axis (CGH-C7 SVA), C2-C7 SVA, neck tilt (NT), and thoracic inlet angle (TIA) were found among the three age groups. Pearson correlation analysis showed positive correlations between the C0-C2 angle and CGH-C7 SVA, C0-C2 angle and C2-C7 SVA, C2-C7 angle and T1 slope, C2-C7 angle and TIA, CGH-C7 SVA and C2-C7 SVA, C2-C7 SVA and T1 slope, T1 slope and TIA, and NT and TIA as well as negative correlations between the C0-C2 angle and C2-C7 angle, C2-C7 angle and CGH-C7 SVA, and C2-C7 angle and C2-C7 SVA. Paired t tests showed significant changes in the C2-C7 angle in groups I and II, and in the CGH-C7 SVA and C2-C7 SVA in all age groups with increasing age.

CONCLUSION

The results indicate that cross correlations exist between different cervical sagittal parameters in adults without symptoms of cervical spinal disease, and the lower cervical curvature and SVA change obviously with increasing age.

LEVEL OF EVIDENCE

3.

The 3 Sagittal Morphotypes That Define the Normal Cervical Spine: A Systematic Review of the Literature and an Analysis of Asymptomatic Volunteers

BACKGROUND

Cervical alignment is vital for maintaining horizontal gaze and sagittal balance. The aims of this study were to summarize previously published descriptions of normative cervical alignment and to analyze a cohort of asymptomatic volunteers in order to identify natural clusters of normal radiographic parameters.

METHODS

We performed a systematic review of the literature on radiographic measurements of asymptomatic volunteers through a search of MEDLINE and ScienceDirect databases. We then performed an analysis of demographic and radiographic parameters of volunteers without back or neck complaints. Only subjects with a chin-brow vertical angle (CBVA) within previously published normal limits were retained for analysis. A 2-step cluster analysis was used to find natural groups of cervical alignment. Differences among groups were investigated with a post hoc analysis of variance (ANOVA).

RESULTS

We included 37 articles in our analysis. There was a broad spectrum of both C2-C7 lordosis-kyphosis and T1 slope across ages and sexes. Of the 119 asymptomatic volunteers who were available for analysis, 84 (with a mean age [and standard deviation] of 49.0 ± 17.1 years) had a CBVA ranging from -4.7° to 17.7°. The cluster analysis identified 3 alignment groups based on cervical lordosis-kyphosis and T1 slope (silhouette measure of cohesion, >0.6). Twenty-seven volunteers (32.1%) were identified as the "kyphotic curve cohort" (KCC) (mean C2-C7 Cobb angle, -8.6° ± 7.3°; mean T1 slope, 17.4° ± 6.6°), 43 volunteers (51.2%) were identified as the "medium lordosis cohort" (MLC) (mean C2-C7 Cobb angle, 8.7° ± 7.2°; mean T1 slope, 26.6° ± 4.0°), and 14 volunteers (16.7%) were identified as the "large lordosis cohort" (LLC) (mean C2-C7 Cobb angle, 21.2° ± 7.2°, mean T1 slope, 39.5° ± 6.4°) (p < 0.001 for both). Moving from KCC to LLC, there was a significant decrease in C0-C2 lordosis (p = 0.016). Examination of the cervical vertebral orientation demonstrated that C4 had a constant orientation relative to the horizontal (p = 0.665). Correlation analysis between C2-C7 and vertebral orientations again demonstrated that C4 orientation was independent of C2-C7 alignment.

CONCLUSIONS

We have identified 3 morphotypes of the cervical spine based on C2-C7 alignment and T1 slope. These findings demonstrate the broad definition of normal cervical alignment and the range of cervical lordosis-kyphosis that is acceptable.

Radiographic benefit of incorporating the inflection between the cervical and thoracic curves in fusion constructs for surgical cervical deformity patients

Purpose:

The aim is to assess the relationship between cervicothoracic inflection point and baseline disability, as well as the relationship between clinical outcomes and pre- to postoperative changes in inflection point.

Methods:

Cervical deformity (CD) patients with baseline and 3-month (3M) postoperative radiographic, clinical, and inflection data were grouped by region of inflection point: C6 or above, C6-C7 to C7-T1, T1, or below. Inflection was defined as: Distal-most level where cervical lordosis (CL) changes to thoracic kyphosis (TK). Differences in alignment and patient factors across pre- and postoperative inflection point groups were assessed, as were outcomes by the inclusion of inflection in the CD-corrective fusion construct.

Results:

A total of 108 patients were included. Preoperative inflection breakdown: C6 or above (42%), C6-C7 to C7-T1 (44%), T1 or below (15%). Surgery was associated with a caudal migration of inflection by 3M: C6 or above (8%), C6-C7 to C7-T1 (58%), T1 or below (33%). For patients with preoperative inflection T1 or below, the inclusion of inflection in the fusion construct was associated with improvements in horizontal gaze (McGregor's Slope included: −11.3° vs. not included: 1.6°, P = 0.038). The inclusion of preoperative inflection in fusion was associated with the superior cervical sagittal vertical axis (cSVA) changes for C6-C7 to C7-T1 patients (−5.2 mm vs. 3.2 mm, P = 0.018). The location of postoperative inflection was associated with variation in 3M alignment: Inflection C6 or above was associated with less Pelvic Tilt (PT), PT and a trend of larger cSVA. Location of inflection or inclusion in fusion was not associated with reoperation or distal junctional kyphosis.

Conclusions:

Incorporating the inflection point between CL and TK in the fusion construct was associated with superior restoration of cervical alignment and horizontal gaze for surgical CD patients.

Characteristics of sagittal spine alignment in female patients with distal radius fractures due to fall

Objectives

Distal radius fractures occur due to reflex clasp when falling. Recently, attention has been focused on the strong relationship between sagittal spine alignment and falls. Therefore, we investigated the parameters of sagittal spinal alignment in distal radius fractures in female patients.

Patients and methods

The subjects were group D: 28 female patients with distal radius fractures aged 50 years or older (mean age: 69.3 years), and group C: 26 healthy female patients without a history of fragility fractures (mean age: 70.5 years). Height, body weight, and body mass index (BMI) were measured as physical indices. As parameters of sagittal spinal alignment, the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumber lordosis (LL), and thoracic kyphosis (TK) were measured on lateral whole-spine plain radiographs in a standing position. The measured physical indices and sagittal spinal alignment parameters were compared between groups.

Results

Height, weight, and BMI did not differ significantly between the two groups. Among the sagittal spinal alignment parameters, PT, PI, SS, LL, and TK did not differ significantly between groups, whereas SVA was significantly higher in group D than in group C (P < 0.05).

Conclusion

In this study, SVA was significantly higher in group D than in group C. As SVA increased, the center of gravity of the body shifts forward, which can cause the body to lose balance and fall. This study suggested that an increase in SVA is associated with distal radius fractures.

Magnetic Resonance Imaging Research of Thoracic Inlet Parameters in the Cervical and Cervicothoracic Spine in Degenerative Cervical Spondylosis

OBJECTIVE

The purpose of this study was to examine the thoracic inlet angle (TIA) and its related parameters in the cervical and cervical-thoracic vertebrae in patients with degenerative cervical spondylosis (DCS) and explore the association of the TIA, tilt angle of the neck, and tilt angle of the first thoracic spine with the cervical degeneration score.

METHODS

Patients with DCS were included from January 2014 to December 2017. The relevant parameters were assessed on T2-weighted magnetic resonance imaging. The association of cervical parameters with the cervical degeneration score was examined by multiple linear regression model.

RESULTS

A total of 204 patients (126 men) were eligible and enrolled, with a mean age of 55-56 years. Men had significantly higher thoracic inlet parameters than women (all P < 0.05). Thoracic inlet parameters were positively correlated with age (all P < 0.05). After adjustment for age and sex, the significant association between the TIA and cervical or cervical-thoracic spine degeneration scores was not observed in all vertebrae. Meanwhile, men had higher vertebral height (VH) and intervertebral disk height (IVDH) than women. Only the VHs of C7, T1, and T2 and the IVDHs of C6-7, T1-2, and T2-3 were significantly and positively associated with the TIA (all P < 0.05).

CONCLUSIONS

Age was positively correlated with thoracic inlet parameters in patients with DCS. Men had significantly higher thoracic inlet parameters than women because the men had higher VHs and IVDHs. However, the TIA was not associated with the level of cervical disk degeneration. The clinical relevance of these findings has not been established.

The Transverse Gravitational Deviation Index, a Novel Gravity Line-Related Spinal Parameter, Relates to Balance Control and Health-Related Quality of Life in Adults With Spinal Deformity

STUDY DESIGN

Prospective cross-sectional case-control study design.

OBJECTIVE

This study aims to analyze the relation between balance control as well as health-related quality of life (HRQOL) in patients with adult spinal deformity (ASD), with a novel gravity line (GL)-related 3D spinal alignment parameter, the transverse gravitational deviation index (TGDI), defined to quantify the transverse plane position of any vertebra with respect to the GL.

SUMMARY OF BACKGROUND DATA

Demographic data and balance control have both been identified as important determinants of HRQOL in ASD patients during a preoperative setting. Therefore, a better understanding of the relation between spinal alignment and balance is required.

METHODS

After informed consent, 15 asymptomatic healthy volunteers (mean age 60.1 ± 11.6 years old) and 55 ASD patients (mean age 63.5 ± 10.1 years old) were included. Relation between performance on BESTest as well as core outcome measures index (COMI) with spinopelvic alignment was explored using General Linear Modeling (GLM). A P-value ≤0.05 was considered statistically significant.

RESULTS

The L3 TGDI was identified to relate to balance control in the total ASD population after correction for confounding demographic factors (P = 0.001; adjusted R = 0.500) and explained 19% of the observed variance in balance performance. In addition, COMI is related to L3 TGDI in a subgroup of ASD patients with combined coronal and sagittal malalignment of L3 (P = 0.027; slope B = 0.047), despite significant influence of age (P = 0.020).

CONCLUSION

In ASD patients with a combined coronal and sagittal malalignment of the L3 vertebra, both the level of balance impairment as well as HRQOL are related to the distance component of the L3 TGDI, that is, the offset between the center of the L3 vertebral body and the GL in the transverse plane.

LEVEL OF EVIDENCE

2.

The change of cervical sagittal parameters plays an important role in clinical outcomes of cervical spondylotic myelopathy after multi-level anterior cervical discectomy and fusion

BACKGROUND

Cervical sagittal parameters were closely related with clinical outcomes after multi-level ACDF. Our purpose was to evaluate the clinical outcomes and cervical sagittal parameters in patients with MCSM after ACDF and to identify the risk factors of poor clinical outcomes.

MATERIAL AND METHODS

ACDF was performed in 89 patients with MCSM. Based on average JOA recovery rate, patients were divided good-outcome group (group GO) and poor-outcome group (group PO). The cervical sagittal parameters including Cobb angle, SVA, T1S, cranial tilt and cervical tilt were measured. Multivariate logistic regression was used to identify risk factors.

RESULTS

Fifty-four patients (60.67%) were divided into group GO, while 35 patients (39.33%) were divided into group PO. Cobb angle, SVA and T1S was corrected from preoperative average 11.80° ± 9.63°, 23.69 mm ± 11.69 mm and 24.43° ± 11.78° to postoperative average 15.08° ± 9.05°, 18.79 mm ± 10.78 mm and 26.92° ± 11.94° respectively (p < 0.001). △Cobb angle (p = 0.008) and △SVA (p = 0.009) showed significantly statistical differences between two groups. Longer symptom duration, lower preoperative JOA score, smaller △Cobb angle and larger △SVA were identified as risk factors of poor clinical outcomes.

CONCLUSION

Multi-level ACDF is an effective surgical method to treat patients with MCSM. However, long duration of preoperative symptoms, lower preoperative JOA score, smaller △Cobb angle and larger △SVA are risk factors for poor outcomes in patients with MCSM after ACDF. Sagittal parameters should be paid attention to in surgery.

Association Between Muscle Strength, Mobility, and the Progression of Hyperkyphosis in the Elderly: The Kurabuchi Cohort Study

BACKGROUND

The progression of hyperkyphosis is a significant factor in declining general health. The purpose of this study was to investigate whether muscle strength and/or mobility is associated with the progression of hyperkyphosis in elderly people.

METHODS

As part of a cohort study of community-dwelling elderly people, handgrip strength and mobility (evaluated with the Timed Up and Go Test: TUG) were assessed at baseline (2005-2006). Kyphosis was also evaluated at baseline and in follow-up examinations 4 years later, with the block method. To exclude the measurement error, the progression of kyphosis was defined as increase of 2 or more blocks. The association of kyphosis progression in each group with handgrip strength and/or mobility was assessed using Poisson regression analysis.

RESULTS

Results on 403 participants were available for the final analysis, and kyphosis progression was observed in 53 (13.1%) of them. Multivariable analysis adjusted for sex, age, baseline block number, bone stiffness, TUG performance, or handgrip strength simultaneously revealed that low handgrip strength (<26 kg in men, <18 kg in women) and low mobility (>13.5 seconds) at baseline were both independently associated with kyphosis progression (adjusted risk ratio [95% confidence interval]: 2.11 [1.06-4.20] and 2.48 [1.26-4.89], respectively).

CONCLUSIONS

Our study showed that low handgrip strength and low mobility are clearly associated with the progression of kyphosis. Further study is needed on the applicability of these results to preventive measures.

Changes in Thoracic Kyphosis and Thoracolumbar Kyphosis in Asymptomatic Korean Male Subjects Aged >50 Years: Do They Progress Above T5, T10, T12, or L2?

Study Design

Retrospective analysis of prospectively collected data.

Purpose

To evaluate the natural progression of segmental kyphosis in thoracic and thoracolumbar spine with advancing age.

Overview of Literature

To our knowledge, the evolution of segmental thoracic kyphosis (TK) in individuals aged >50 years has not been reported.

Methods

Total 179 normal, asymptomatic Korean men were divided in to three groups (6th, 7th, and 8th decade) according to their age. Standard sagittal spinopelvic parameters, including TK and thoracolumbar kyphosis, were measured and subdivided into the following four segments: A (C7 upper end plate [UEP]–T5 UEP), B (T5 UEP–T10 UEP), C (T10 UEP–T12 lower end plate [LEP]), and D (T12 LEP–L2 LEP). These segments of the three study groups were analyzed.

Results

In segment B, the segmental kyphosis of group 3 (20.2°±8.0°) showed a statistically larger value than that of group 1 (15.6°±6.8°) and group 2 (16.7°±8.8°) (p=0.017). In segment C, the segmental kyphosis of group 2 (12.9°±6.5°) and group 3 (12.2°±7.1°) showed statistically larger values than that of group 1 (9.5°±6.2°) (p=0.016). The A and D segments of the three groups were not significantly different.

Conclusions

Increased TK was observed in the middle (segment B) and lower (segment C) thoracic segments in normal asymptomatic male subjects with age. The results from the natural progression of segmental kyphosis with age would provide baseline reference data to help surgeons choose the optimal point of the upper instrumented vertebra level for preventing proximal junctional kyphosis.

Age-related Changes in Cervical Sagittal Alignment: A Radiographic Analysis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To identify age-related changes in cervical sagittal parameters using standard radiographs.

SUMMARY OF BACKGROUND DATA

Cervical sagittal balance is important for the maintenance of neutral head posture and horizontal gaze. Degenerative changes in the cervical spine that occur with aging may alter cervical sagittal balance, which can lead to chronic neck pain and predispose to various cervical spine pathologies.

METHODS

We performed a retrospective cohort study of 151 patients with lateral cervical spine radiographs taken at our institution between December 2017 and June 2018. Cervical sagittal parameters were measured, including C1 inclination, C2 slope, C2-C7 Cobb angle, cervical sagittal vertical axis (cSVA), cervical tilt, upper and lower C7 slopes, T1 slope, and T1 slope minus cervical lordosis (TS-CL). The association between age and cervical sagittal parameters was assessed using the Pearson correlation coefficient and a linear regression analysis. An analysis of variance (ANOVA) with Tukey adjustments was then performed to identify differences in cervical sagittal parameters among patients aged 18 to 39 years, 40 to 64 years, and >64 years of age.

RESULTS

There were positive correlations between age and C2-C7 Cobb angle (r = 0.231, P = 0.004), upper C7 slope (r = 0.280, P < 0.001), lower C7 slope (r = 0.283, P < 0.001), and T1 slope (r = 0.189, P = 0.020). Upper C7 slope (R = 0.079) and lower C7 slope (R = 0.074) had the strongest correlation with age in the linear regression analysis. The ANOVA found significant differences among the age subgroups in terms of C2-C7 Cobb angle (P = 0.002), upper C7 slope (P < 0.001), lower C7 slope (P < 0.001), and T1 slope (P = 0.031). Patients >64 years old had significantly higher C2-C7 Cobb angle, upper C7 slope, lower C7 slope, and T1 slope.

CONCLUSION

Changes in cervical sagittal alignment with age are characterized by increased cervical lordosis and increased thoracic kyphosis.

LEVEL OF EVIDENCE

3.

Sagittal Reconstruction and Clinical Outcome Using Traditional ACDF, Versus Stand-alone ACDF Versus TDR: A Systematic Review and Quantitative Analysis

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the difference in postoperative sagittal alignment when single level cervical radiculopathy or myelopathy is treated with an anterior cervical discectomy and fusion (ACDF) using a structural graft and plate, a stand-alone ACDF, or a total disc arthroplasty (TDR). We also wanted to determine if postoperative sagittal alignment impacted clinical outcomes in this patient population.

SUMMARY OF BACKGROUND DATA

Although there are several accepted techniques for interbody reconstruction during single level anterior cervical surgery, little is known on the impact of any of them on segmental and regional sagittal alignment.

METHODS

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines of the PubMed, Embase, and Cochrane databases. Only studies which contained pre and postoperative C2-7 Cobb angles as well as Neck Disability Index (NDI) scores following single level traditional ACDF with plate and cage, stand-alone ACDF, or TDR with at least 1 year follow up were included.

RESULTS

There were 12 publications that fulfilled the inclusion criteria with a total of 658 patients. Cluster regression analysis showed no difference between treatment arms at each respective time-point or in the overall change in NDI from preoperative to postoperative (P = 0.88). Cluster regression analysis showed no difference between treatment arms at each respective time point or in the overall change in lordosis from pre-op to post-op (P = 0.93).

CONCLUSION

This review provides evidence that while NDI scores improved across all devices, there was no significant difference in NDI improvement or C2-7 Cobb angle change between single level traditional ACDF, stand-alone ACDF, or TDR. Although TDR has not been considered a lordosis producing operation, our investigation shows it does not differ significantly in sagittal profile from other cervical fusion techniques. Moreover, we show that the NDI score improved, regardless of device implanted.

LEVEL OF EVIDENCE

1.

Zero-profile Hyperlordotic Spacer for Cervical Deformity Correction: Case Presentation and Technical Note

Cervical spine deformity (CSD) can negatively affect the health-related quality of life (HRQOL) of patients, particularly the elderly, thus representing a socioeconomic problem of increasing importance. While surgical deformity correction has been linked to improved HRQOL, no universally accepted consensus exists for the operative management of CSD.

The authors demonstrate the feasibility of CSD correction, implementing anterior and posterior cervical osteotomies combined with the placement of multiple consecutive zero-profile hyperlordotic interbody spacers in a 55-year-old male with cervical kyphosis. This technique resulted in the satisfactory restoration of the patient’s cervical alignment and significantly ameliorated his presenting symptoms. The patient demonstrated maintained cervical lordosis and he remained symptom-free at the one-year follow-up.

The use of multiple consecutive zero-profile cervical interbody spacers can effectively and safely be utilized for the treatment of CSD. Further studies are needed to compare this technique with other standard surgeries used for CSD correction.

Comparison of Lumbosacral Alignment in Geriatric and Non-Geriatric patients suffering low back pain

Objective:

Lumbosacral alignment is a crucial factor for an appropriate spinal function. Changes in spinal alignment lead to diminished body biomechanics. Additionally, lumbosacral alignment may affect quality of life, sagittal balance and fall risk in elderly. In this study, we aimed to compare lumbosacral alignment in geriatric and non-geriatric patients suffering from low back pain.

Methods:

A total of 202 (120 male and 82 female) patients who visited to physical medicine and rehabilitation clinic with low back pain between January 2017 and August 2017 were enrolled in this study. Standing lateral lumbar radiographs were obtained from the electronic hospital database. Lumbar lordosis angle, sacral tilt, lumbosacral angle and lumbosacral disc angle were calculated on lateral standing lumbar radiographs.

Results:

The mean age of the non-geriatric group was 43.02 ± 13.20 years, the geriatric group was 71.61 ± 6.42 years. In geriatric patients, lumbar lordosis angle, sacral tilt and lumbosacral disc angle were significantly smaller (p = 0.042, p = 0.017 and p = 0.017). No significant differences were observed in lumbosacral angle between the groups (p = 0.508).

Conclusion:

Our study indicates the specific changes in lumbosacral alignment with aging. Identifying these changes in lumbosacral alignment in the geriatric population will enable to create proper rehabilitation strategies.

Could pelvic parameters determine optimal postoperative thoracic kyphosis in Lenke type 1 AIS patients?

Background

A proper restoration of sagittal alignment is essential in AIS patients, but few studies provided a formula to predict an optimal surgical thoracic kyphosis (TK) gain in adolescent idiopathic scoliosis (AIS) patients. A formula was recently proposed (LL = (PI+TK)/2 + 10) to predict the optimal lumbar lordosis (LL) in adult spinal deformity patients, which has not been validated in adolescents. The aim of this study is to establish a formula with TK and pelvic parameters in normal adolescents and predict an optimal TK with this formula pre- and post-operatively in Lenke 1 AIS patients.

Methods

A total of 60 asymptomatic adolescents were used to validate the proposed formula. The subject was considered to match with the formula, if the difference between the virtual TK and the theoretical TK was less than 10°. Then regression analysis was performed to establish a new formula to predict TK in adolescents. The predictive efficiency of the new formula was also validated in 40 Lenke 1 AIS patients.

Results

Of the 60 asymptomatic adolescents, only 26 (43.33%) asymptomatic adolescents matched with the adjusted formula: TK = 2 × (LL-10)-PI. The paired t test revealed a significantly different theoretical TK (tTK) compared to the virtual TK (41.23 ± 18.29° vs. 24.80 ± 8.75°, P < 0.001). Multiple linear regression showed that TK had a relationship with LL, SS and age (R² = 0.331): TK = − 0.785 × LL-0.843 × SS + 0.858 × age + 3.754. There were 27 (67.50%), 32 (80.00%) and 35 (87.50%) Lenke 1 AIS patients matched this formula preoperatively, postoperatively and at the last follow-up.

Conclusion

Our results revealed that the predictive formula for sagittal alignment for adults was not applicable in adolescents. This study established a new predictive formula for TK based on asymptomatic adolescents. In Lenke 1 AIS patients, post-op TK in 87.5% of patients matched the predictive value, indicating that the new formula can be considered as a reference when making a surgery strategy.

Preoperative cervical sagittal alignment parameters and their impacts on myelopathy in patients with cervical spondylotic myelopathy: a retrospective study

Background

Cervical sagittal alignment plays an important role in the pathogenesis of cervical spondylotic myelopathy (CSM), but there are limited studies on the cervical sagittal parameters in CSM patients and their correlations with myelopathy. The aim of this study is to investigate the correlations among the preoperative cervical sagittal alignment parameters and their correlations with the development of myelopathy in patients with CSM.

Methods

We retrospectively collected 212 patients with CSM who underwent surgical interventions. Gender, age, modified Japanese Orthopedic Association score (mJOA), cervical lordosis (CL), C2–C7 sagittal vertical axis (C2–C7 SVA), T1 slope (T1S), neck tilt (NT) and thoracic inlet angle (TIA) were collected before operation. Interobserver and intraobserver reliability were calculated for all measurements (intraclass correlation coefficient, ICC). Data were analyzed with Pearson and Spearman correlation tests and multiple linear regression analysis.

Results

A total of 212 patients with CSM were included in this study (male: 136, female: 76) with an average age of 54.5 ± 10.1 years old. Intraobserver and interobserver reliability for all included radiographic parameters presented good to excellent agreement (ICC > 0.7). No significant differences in demographic and radiological parameters have been observed between males and females (P > 0.05). We found statistically significant correlations among the following parameters: age with CL (r = 0.135, P = 0.049), age with T1S (r = 0.222, P = 0.001), CL with T1S (r = 0.291, P < 0.001), CL with C2-C7 SVA (r =  − 0.395, P < 0.001), mJOA with age (r =  − 0.274, P < 0.001), mJOA with C2–C7 SVA (r =  − 0.219, P < 0.001) and mJOA with T₁S(r =  − 0.171, p = 0.013). Linear regression analysis showed that C2–C7 SVA was the predictor of CL (adjusted R² = 0.152, P < 0.001) and multiple linear regression showed that age combined with C2–C7 SVA was a sensitive predictor of mJOA (adjusted R² = 0.106, P < 0.001).

Discussion

There were significant correlations among certain preoperative cervical sagittal parameters in CSM patients. CL was the only predictor of C2–C7 SVA. Age combined with C2–C7 SVA could predict the severity of myelopathy.