The change of cervical spine alignment along with aging in asymptomatic population: a preliminary analysis

Reduced Vertebral Hounsfield Unit Values in the Bridging Group of Ossification-Related Segments in Patients with Ossification of the Posterior Longitudinal Ligament of the Cervical Spine

BACKGROUND

Increased systemic bone mineral density has been reported in patients with ossification of the posterior longitudinal ligament (OPLL). This study investigated the differences in vertebral Hounsfield unit (HU) values between the bridged and nonbridged groups of patients with OPLL of the cervical spine at the ossification-related segments.

METHODS

A total of 436 ossification-related segments from 157 patients were involved in the study. X-ray and computed tomography scans were used to assess the segmental cervical range of motion (ROM), C2-7 Cobb angle, K-line, ossification thickness, maximum canal occupancy, HU values, and presence and type of OPLL.

RESULTS

In terms of imaging parameters, HU values were significantly higher in the OPLL group (P < 0.001), whereas the ROM was greater in the control group (P < 0.05). In the OPLL group, the K-line positive group had a better C2-7 Cobb angle and greater T1 slope. The ossification-related segments were divided into bridging and nonbridging groups, with smaller vertebral HU values, thicker ossification lesions, greater canal occupation, and reduced interbody mobility in the bridging group. However, we found no significant correlation among segmental ROM, ossified material thickness, maximum canal occupancy of the ossified material, and segmental HU values.

CONCLUSIONS

We found that the mean HU value of the cervical spine in patients with OPLL was higher than that of the control group, and the ROM was smaller than that of the control group, with the smallest ROM in the continuous type. In the ossification-related segments, the bridging group exhibited lower vertebral HU values, reduced segmental mobility, and thicker ossification thickness.

Movement control of the cervical spine declines with aging: a cross-sectional study

BACKGROUND

Previous studies suggest that cervical spine position sense declines with age, while the relationship between aging and cervical spine movement control remains unknown.

OBJECTIVE

To investigate the relationship between age and cervical spine movement control in asymptomatic adults.

METHODS

One hundred five asymptomatic adults (21-79 years old) were included. The Butterfly test (performed with an inertial measurement unit) was used to assess movement control of the cervical spine, in which participants tracked an unpredictable moving target with active head and neck movements at three different movement path difficulty levels (3 repetitions each). The determined parameters were amplitude accuracy (AA), time on target (ToT), undershoot (U) and overshoot (O). Spearman's rank correlation coefficient and simple linear regression analysis were used to assess the relationship between age and each parameter.

RESULTS

A significant relationship was demonstrated between advancing age and the AA, ToT and U parameters for all three movement path difficulty levels (p ≤ .001), but not for the O parameter (p > .05). Advancing age explained 19.8-30.4%, 24.5-30.8% and 33.7-37.2% of the variance in the AA, ToT, and U parameters, respectively.

CONCLUSION

The results suggest that cervical spine movement control declines with aging in an asymptomatic population. Clinicians may need to monitor potential deficits in cervicocephalic kinesthesia in older asymptomatic adults, as these impairments may have a considerable impact on their functional abilities.

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.

Comparative study of preoperative sagittal alignment between patients with multisegment cervical ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy

BACKGROUND CONTEXT

Preoperative sagittal alignment is of great significance in the development of spinal deformities, degenerative diseases, preoperative planning, postoperative clinical evaluation, and functional recovery. However, few reports have focused on the difference in preoperative sagittal alignment between patients with ossification of the posterior longitudinal ligament (OPLL) and patients with cervical spondylotic myelopathy (CSM).

PURPOSE

To compare preoperative sagittal alignment between patients with multisegment cervical OPLL and multilevel CSM.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

A total of 243 patients were included in this study.

OUTCOME MEASURES

The outcome measures were the Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score, number of hand actions in 10 seconds, hand-grip strength, C2 to C7 Cobb angle, C2 to C5 Cobb angle, C5 to C7 Cobb angle, C2 to C7 sagittal vertical axis, C7 slope, T1 slope, K-line, K-line tilt, and range of motion (ROM).

METHODS

The outcome measures were calculated in the OPLL group and CSM group and the data were analyzed using the unpaired t-test, χ² test, and one-way analysis of variance.

RESULTS

A total of 243 patients (136 men, 107 women; mean age, 59.1±10.6 years) underwent surgical treatment from September 2013 to December 2021. In total, 123 patients were diagnosed with multisegment cervical OPLL, including continuous type (n=39), segmental type (n=38), and mixed type (n=46). The remaining 120 patients had multisegment CSM. The disease course in the OPLL group was significantly shorter than that in the CSM group (p<.05). Among the above preoperative measurements, the JOA score, number of hand actions in 10 seconds, hand-grip strength, and VAS score were not significantly different between the two groups (p>.05). The C2 to C7 Cobb angle was significantly larger in the OPLL than CSM group (17.7°±9.2° and 14.9°±9.3°, respectively; p< .05), as was the C5 to C7 Cobb angle (10.0°±6.3° and 7.5°±6.1°, respectively; p<.05). The ROM was significantly smaller in the OPLL than CSM group (33.1°±8.1° and 40.1°±10.9°, respectively; p<.001). Within the OPLL group, the ROM was significantly smaller in the continuous type than in the segmental type (p<.05).

CONCLUSION

Patients with multisegment cervical OPLL have greater lordotic preoperative sagittal alignment and smaller preoperative ROM than patients with CSM.

Analysis of sagittal parameters for easier and more accurate determination of cervical spine alignment

Cross-sectional comparative study. This study aimed to analyze the role of cervical parameters, in terms of the perception process, when evaluating cervical sagittal balance on an X-ray image. Reports on the role of cervical parameters in the perception of cervical sagittal balance have not been made. The study included 4 board-certified neurosurgeons and 6 residents of a neurosurgical department. They were instructed to answer a total of 40 questions. The parameter that was the most helpful in deriving the answer was checked. The correct answer rate, dependency on the parameter, and correct answer contribution of the parameter were analyzed. Among the various parameters, 5 parameters [C2-7 angle (C2-7A), T1 slope minus cervical lordosis (T1s-CL), C2 slope (C2s), C7 slope (C7s), and C2-7 sagittal vertical axis) were selected. The simple parameter (C2s, C7s) has a higher dependency and correct answer contribution than the complex parameter (C2-7A, T1s-CL). The angular (C2-7A, T1s-CL, C2s, C7s) parameters have a higher dependency; however, both the length and angular parameters correct answer contribution were similar. The cervical parameters that have simpler properties were highly preferred and had a lower perception error.

Variation of cervical sagittal alignment parameters according to age and pelvic incidence in degenerative spinal deformity patients

INTRODUCTION

In asymptomatic subjects, variations of cervical sagittal alignment parameters according to age and spinopelvic organization have been reported. A large range of compensation phenomena has been observed in degenerative spinal deformity in order to maintain horizontal gaze, but it remains unclear how age and spinopelvic morphology could additionally influence cervical alignment. The aim of this observational retrospective study was to describe the distribution of cervical sagittal alignment parameters according to age and pelvic incidence in subjects with and without degenerative spinal deformity in order to precisely evaluate cervical compensation phenomena in adult spinal deformity (ASD).

MATERIAL AND METHODS

Radiographs of 478 subjects (327 females and 151 males) were distributed into 235 asymptomatic and 243 deformed subjects. Occipito-cervical parameters were McGregor-C1, McGregor-C2, C1-C2 and occipito-C2 angles. The cervicothoracic inflection point (CTIP) was determined. Caudal cervical sagittal alignment parameters were: C2-C7 lordosis, C2-apex (superior arch), apex-CTIP (inferior arch), occipito-C3 and occipito-C4 angles, C7-slope and T1-slope. The distribution of parameters was analyzed using a Bayesian inference (significant when Pr > 0.975 or Pr < 0.025). Comparisons between asymptomatic and deformed subjects were done after matching on age (40-60 years; > 60 years) and on PI (< 45°; 45-60°; > 60°).

RESULTS

Among occipito-cervical parameters, there was no significant change in McGregor-C1 angle. However, McGregor-C2 angle was significantly higher in the ASD group (Pr = 0.0029), with influence of age (Pr = 0.023), but PI influence. C1-C2 lordosis was significantly higher in the ASD group compared to the asymptomatic group (Pr < 0.0007), without influence of age or PI noticed. C2-C7 lordosis was also higher in the ASD group (Pr < 0.025) with a role of age and PI (Pr < 0.025). Cervical lordosis in the superior arch was significantly higher in the ASD group (Pr > 0.999), without influence of age or PI. In the inferior arch, the lordosis angle was not modified according to the group, but there was an influence of age (Pr < 0.0007). C7-slope and T1-slope were higher according the age group (Pr < 0.0012), without influence of the group or PI.

CONCLUSION

This observational study highlights cervical sagittal alignment adaptations in degenerative spinal deformity, matched on age and pelvic incidence. The inferior cervical spine seemed to be modified with a higher lordosis, increasing with age responding to the age-related thoracic kyphosis increase. In addition to that, the superior cervical spine hyperextends more in adult degenerative deformity to maintain horizontal gaze.

LEVEL OF EVIDENCE

III.

Description of age-related changes in cervical sagittal alignment based on pelvic incidence classification in asymptomatic Chinese population

PURPOSE

To investigate the pelvic incidence (PI)- and age-related cervical alignment changes of Chinese healthy population.

METHODS

Six hundred and twenty-five asymptomatic adult subjects, who underwent the standing whole spinal radiograph, were recruited in this work. The sagittal parameters were measured, including Occipito-C2 angle (O-C2), C2-7 angle (C2-7), cranial arch, caudal arch, T1-slope (T1S), C2-7 sagittal vertical axis (C2-7 SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), PI, and sagittal vertical axis (SVA). All subjects were stratified into 5 age groups, namely 40-59 years, 60-64 years, 65-69 years, 70-74 years, and 75 years and above, with each age group further divided into 2 subgroups based on PI (deeming PI < 50° as low PI, and PI ≥ 50° as high PI). The correlations between PI or age, and other sagittal parameters were assessed. The age-related changes of sagittal parameters in each PI subgroup were also assessed, followed by one-way analysis of variance analysis for change comparison between age groups.

RESULTS

The average cervical sagittal parameters were as below: 18.2 ± 6.8° for O-C2, 10.4 ± 10.2° for C2-7, 3.9 ± 7.5° for cranial arch, 6.5 ± 7.1° for caudal arch, 23.6 ± 7.3° for T1S, and 21.0 ± 9.7 mm for C2-7 SVA. There was no obvious difference observed between PI and cervical sagittal parameters, excepting for caudal arch. While, C2-7, cranial arch, caudal arch, T1S, and C2-7 SVA increased remarkably with the age. Thereof, C2-7 exhibited great increases at the age of 60-64 years and 70-74 years, respectively, cranial arch increased notably at 60-64 years of age, and caudal arch developed obviously at 70-74 years of age, regardless of PI.

CONCLUSION

This study showed the PI- and age-related cervical alignment changes of Chinese healthy population. Based on the classification in our study, high or low PI apparently did not correlate with the occurrence of cervical degenerative disease.

Comparison of three methods for measuring C0-1 angles and C0-2 angles

BACKGROUND

The mutual compensatory relationship between the upper cervical sagittal alignment and the lower cervical sagittal alignment has been repeatedly reported. However, the evaluation of the upper cervical sagittal parameters are varied in previous studies. This retrospective study was performed to compare three methods for measuring the upper cervical sagittal parameters.

METHODS

A total of 263 individuals with standing neutral lateral cervical radiographs were included in this study. The Frankfort horizontal line (FHL), foramen magnum line (FML), and McGregor line (ML) were separately used as the reference lines for measuring the C0-1 angle and C0-2 angle. Intraclass correlation (ICC) values were used to compare the consistency and repeatability of the three methods. Pearson's correlation analysis was used to analyze the correlation between the sagittal parameters of the upper and lower cervical spine.

RESULTS

The interobserver and intraobserver ICC values obtained from using the ML to measure the C0-1 angle and C0-2 angle were both higher than those obtained from using the FML or FHL. The C0-1 angle and C0-2 angle measured by the three methods were negatively correlated with the C2-7 angle. The upper sagittal parameters measured by the FHL were the most correlated with the C2-7 angle. The correlation between the C0-1 angle measured by the three methods and the C0-2 angle measured with the FHL or ML and the C2-7 angle increased with aging.

CONCLUSION

Use of the ML to measure the C0-1 angle and C0-2 angle has higher reliability. Use of the FHL to measure the sagittal alignment of the upper cervical spine is more suitable for evaluating the compensation mechanism between the upper and the lower cervical spine.

Age-related changes in cervical sagittal alignment: based on 625 Chinese asymptomatic subjects

PURPOSE

This work aimed to provide a comprehensive description of cervical alignment including cranial arch and caudal arch according to age, thus offering a reference database for cervical deformity treatment.

METHODS

Total 150 males and 475 females aged at 48-88 were enrolled from August 2021 to May 2022. Radiographic parameters were measured, including Occipito-C2 angle (O-C2), C2-7 angle (C2-7), cranial arch, caudal arch, T1-slope (T1s), and C2-7 sagittal vertical axis (C2-7 SVA). Pearson correlation coefficient was employed in analyzing associations among sagittal parameters and between age and each parameter. Five groups were set according to different age stages, namely group with age 40-59 (N = 77), group with age 60-64 (N = 189), group with age 65-69 (N = 214), group with age 70-74 (N = 97), and group with age exceeding 75 (N = 48). An analysis of variance (ANOVA) test was applied to compare multi-sets of cervical sagittal parameters (CSPs). Chi-square test or Fisher's exact test was used in assessing the relationships of various cervical alignment patterns with age groups.

RESULTS

T1s exhibited the strongest correlation with C2-7 (r = 0.655) and caudal arch (r = 0.561), and moderately correlated with cranial arch (r = 0.355). The positive correlations between age and C2-7 angle (r = 0.189, P < 0.001), cranial arch (r = 0.150, P < 0.001), caudal arch (r = 0.112, P = 0.005), T1s (r = 0.250, P < 0.001), as well as C2-7 SVA (r = 0.090, P = 0.024) were observed. Moreover, two progressive growths of C2-7 were shown after 60-64 and 70-74 years old, respectively. Thereof, cranial arch increased greatly after the age of 60-64, followed by a relative stability in the degeneration. The notable growth of caudal arch was observed after the age of 70-74, and the growth remained stable when exceeding the age of 75. The difference between cervical alignment patterns and age groups was obvious (Fisher's exact test P < 0.001).

CONCLUSION

This work explored in detail the normal reference values of cervical sagittal alignment including cranial arch and caudal arch under different age groups. Age-related changes in cervical alignment depended on the increase in the cranial and caudal arches in different proportions with age.

Biomechanical influence of T1 tilt alteration on adjacent segments after anterior cervical fusion

Background: Anterior cervical fusion (ACF) has become a standard treatment approach to effectively alleviate symptoms in patients with cervical spondylotic myelopathy and radiculopathy. However, alteration of cervical sagittal alignment may accelerate degeneration at segments adjacent to the fusion and thereby compromise the surgical outcome. It remains unknown whether changes in T1 tilt, an important parameter of cervical sagittal alignment, may cause redistribution of biomechanical loading on adjacent segments after ACF surgery. Objective: The objective was to examine the effects of T1 tilt angles on biomechanical responses (i.e.range of motion (ROM) and intradiscal VonMises stress) of the cervical spine before and after ACF. Methods: C2-T1 FE models for pre- and postoperative C4-C6 fusion were constructed on the basis of our previous work. Varying T1 tilts of -10°, -5°, 0°, 5°, and 10° were modeled with an imposed flexion-extension rotation at the T1 inferior endplate for the C2-T1 models. The flexion-extension ROM and intradiscal VonMises stress of functional spinal units were compared between the pre- and postoperative C2-T1 FE models of different T1 tilts. Results: The spinal segments adjacent to ACF demonstrated higher ROM ratios after the operation regardless of T1 tilt. The segmental ROM ratio distribution was influenced as T1 tilt varied and loading conditions, which were more obvious during displacement-control loading of extension. Regardless of T1 tilt, intradiscal VonMises stress was greatly increased at the adjacent segments after the operation. As T1 tilt increased, intradiscal stress at C3-C4 decreased under 30° flexion and increased under 15° extension. The contrary trend was observed at the C6-C7 segment, where the intradiscal stress increased with the increasing T1 tilt under 30° flexion and decreased under 15° extension. Conclusion: T1 tilt change may change biomechanical loadings of cervical spine segments, especially of the adjacent segments after ACF. Extension may be more susceptible to T1 tilt change.

Ageing and degeneration analysis using ageing-related dynamic attention on lateral cephalometric radiographs

With the increase of the ageing in the world's population, the ageing and degeneration studies of physiological characteristics in human skin, bones, and muscles become important topics. Research on the ageing of bones, especially the skull, are paid much attention in recent years. In this study, a novel deep learning method representing the ageing-related dynamic attention (ARDA) is proposed. The proposed method can quantitatively display the ageing salience of the bones and their change patterns with age on lateral cephalometric radiographs images (LCR) images containing the craniofacial and cervical spine. An age estimation-based deep learning model based on 14142 LCR images from 4 to 40 years old individuals is trained to extract ageing-related features, and based on these features the ageing salience maps are generated by the Grad-CAM method. All ageing salience maps with the same age are merged as an ARDA map corresponding to that age. Ageing salience maps show that ARDA is mainly concentrated in three regions in LCR images: the teeth, craniofacial, and cervical spine regions. Furthermore, the dynamic distribution of ARDA at different ages and instances in LCR images is quantitatively analyzed. The experimental results on 3014 cases show that ARDA can accurately reflect the development and degeneration patterns in LCR images.

The Difference of Sagittal Correction of Adult Subaxial Cervical Spine Surgery According to Age: A Retrospective Study

Objective

At present, the true sagittal alignment of the cervical spine is uncertain, resulting in no standard reference for subaxial cervical surgery. So, we aimed to explore the age difference of normal cervical sagittal alignment and to further investigate the mid‐and long‐term changes of sagittal alignment after subaxial cervical spine surgery.

Materials and Methods

This was a retrospective study and 1223 asymptomatic volunteers and 79 patients undergoing subaxial cervical spine surgery were retrospectively reviewed in total. Asymptomatic volunteers and patients were divided into six subgroups: 20–29, 30–39, 40–49, 50–59, 60–69 and ≥70 groups. The age difference and trend with age of cervical sagittal parameters of asymptomatic volunteers were assessed by cervical lateral radiography and analyzed by ANOVA test, and the regression equation of C2‐7 Cobb was established via multiple linear regression. Based on the C2‐7 Cobb regression equations of different ages, the theoretical value, deviation value, loss value of the C2‐7 Cobb, and JOA recovery rate of patients were calculated, and the correlation among the loss value, deviation value of the C2‐7 Cobb, and JOA recovery rate of the 79 patients was evaluated by Pearson correlation analysis.

Results

For the asymptomatic volunteers, the C0‐2 Cobb decreased gradually with increasing age. The C2‐7 Cobb, C2‐7 SVA, T1S, NT, and TIA increased gradually with increasing age. The CBVA fluctuated with increasing age. T1S demonstrated a moderate correlation with C2‐7 Cobb (r = 0.60, p < 0.01); C0‐2 Cobb, C2‐7 SVA, CBVA, and TIA demonstrated a fair correlation with C2‐7 Cobb (r = −0.30, −0.33, 0.41, 0.40, p < 0.01); age demonstrated a poor correlation with C2‐7 Cobb (r = 0.19, p < 0.01). The regression equations of C2‐7 Cobb were established using C0‐2 Cobb, C2‐7 SVA, CBVA, and T1S. For the patients with subaxial cervical spine surgery, the loss of C2‐7 Cobb was moderately correlated with the deviation of C2‐7 Cobb (r = 0.33, p < 0.01).

Conclusion

The age difference of cervical sagittal alignment was obvious, and the C2‐7 Cobb increased with age especially. The closer the postoperative C2‐7 Cobb was to the theoretical value of corresponding age, the smaller the loss of correction angle was, and the better the mid‐ and long‐term outcomes. The personalized sagittal reconstruction should be performed according to age difference for subaxial cervical spine surgery.

Variation of cervical sagittal alignment parameters according to gender, pelvic incidence and age

PURPOSE

The aim was to describe radiographic cervical sagittal alignment variations according to age, gender and pelvic incidence (PI) and to investigate relationships with thoracic alignment.

METHODS

A total of 2599 individuals (5-93 years) without spinal deformity were studied. Cranial cervical parameters were: McGregor slope, occipita-C2 angle, McGregor-C2 lordosis and C1-C2 lordosis. Caudal cervical parameters were: C2-C7, cranial arch and caudal arch lordosis and C7- and T1-slope. A Bayesian inference compared parameter distributions. Correlations with spinopelvic and global alignment parameters were investigated.

RESULTS

Among cranial cervical parameters, variations of McGregor slope were non-significant. McGregor-C2 lordosis and C1-C2 lordosis were smaller in males and increased significantly during growth, whereas the occipito-C2 angle decreased (Pr > 0.95). The occipito-C2 angle was larger and McGregor-C2 lordosis was smaller in low PI (Pr > 0.95). Among caudal cervical parameters, C2-C7 lordosis and C7- and T1-slope were larger in males and increased after 50 years (Pr > 0.95). Lordosis changes were non-significant in the cranial arch, whereas values increased in the caudal arch after 35 years (Pr > 0.95). Caudal parameter differences were non-significant between PI groups. Strong correlations existed between C2-C7, caudal arch lordosis, C7-slope, T1-slope and thoracic kyphosis. The sagittal vertical axis C2 correlated with caudal arch lordosis and T1-slope (ρ > 0.5; Pr > 0.95).

CONCLUSION

Cervical alignment parameters vary according to age, gender and PI. In the cranial cervical spine, changes occur mainly during growth. In the caudal cervical spine, lordosis increases in the caudal arch, which is related to thoracic kyphosis increase with age. The caudal cervical arch acts as a compensatory segment by progressive extension, allowing horizontal gaze.

Relationship between TIA minus C0-7 angle and C2-7 SVA: analysis of 113 symptomatic patients

Background

Measurement of T1 slope (T1S) can be difficult due to the anatomical positioning of the shoulders. And thoracic inlet angle (TIA) was a morphological parameter and not changed by the position. We proposed a new parameter, TIA minus C0-7 angle (TIA-C07), to evaluate C2-7 SVA in order to overcome the T1S imperfection.

Methods

This was a retrospective radiological analysis of symptomatic subjects. The following cervical parameters were measured: Cervical lordosis angle (CL), C0-7 angle (C0-7), occiput-C2 lordosis angle (O-C2), C2-7 sagittal vertical axis (C2–7 SVA), TIA and TIA-C07. The Pearson correlation test was calculated, and the stepwise multiple regression analysis was conducted to determine the best predictor for C2-7 SVA. A paired sample t test was used to compare the predicted and measured C2-7 SVA.

Results

The mean age of 113 patients was 60.02 ± 9.67. The average O-C2, CL, C0-7, TIA, TIA-C07 and C2-C7 SVA was 29.24 ± 8.48°, 13.67 ± 11.22°, 42.91 ± 11.44°, 76.07 ± 9.54°, 33.16 ± 13.18° and 21.34 ± 11.42 mm. The predictive formula was founded: C2-7 SVA = 2.80 + 0.56 * (TIA—C07) (R = 0.645, R2 = 0.416). There was no statistical difference between the predicted and the measured C2-7 SVA (t = 0.085, P = 0.933).

Conclusions

TIA and C0-7 mismatch may significantly impact cervical alignment, and a greater T1A-C07 was related to a greater degree of C2-7 SVA. TIA-C07 may be a more important predictor for C2-7 SVA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05301-0.

Case Report of Angular Post-Tuberculotic Kyphosis Corrected Through Pedicle Subtraction Osteotomy Above C7

BACKGROUND AND IMPORTANCE

Angular cervical kyphosis and its association with syringomyelia were rarely described. Correcting this kind of deformity from the front is extremely difficult or even impossible. Meanwhile, no study has made a report about correcting angular cervical kyphosis through pedicle subtraction osteotomy (PSO) above C7 because of the special anatomy of the vertebral artery. This is the first case of cervical deformity correction through PSO above C7.

CLINICAL PRESENTATION

We present the case of a 52-yr-old man who previously underwent debridement, decompression, and skull traction for cervical tuberculosis at age 6 yr. The sequelae of right-hand weakness occurred after surgery, and cervical kyphosis formed gradually. The patient recently started to complain of a severe neck pain. X-rays showed a cervical sagittal malalignment due to the angular kyphosis. Computed tomography scans revealed a fused angular kyphosis at C6-7, and MRI showed a long syringomyelia distal to the kyphosis. The definite diagnosis of the patient was post-tuberculotic cervical angular kyphosis, and because of the extremely narrow surgery corridor from the front, we decided to perform the surgery in a posterior approach. Hence, the patient was treated with the PSO with a long-segment pedicle screw fixation from C3 to T5 and received satisfactory angular kyphosis correction.

CONCLUSION

PSO above C7 to correct angular cervical kyphosis is feasible and reasonable when there is no other better solution, and it can achieve a satisfactory kyphotic deformity correction.

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.

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.

Cervical disc arthroplasty versus anterior cervical discectomy and fusion for the treatment of single-level disc degenerative disease with preoperative reversible kyphosis

OBJECTIVE

Whether and when cervical disc arthroplasty (CDA) could be indicated for preoperative cervical spine kyphosis is unclear. The purpose of the study was to compare the clinical and radiological outcomes of single-level CDA and single-level anterior cervical discectomy and fusion (ACDF) in the patient with preoperative reversible kyphosis.

PATIENTS AND METHODS

From 2014-2018, patients who underwent single-level CDA and single-level ACDF were consecutively reviewed. The Japanese Orthopedic Association score, Neck Disability Index and VAS were used to evaluate clinical outcomes. Range of motion (ROM), C2-7 Cobb angle, functional spinal unit (FSU) angle, and heterotopic ossification (HO) were assessed.

RESULTS

Thirty-eight CDA patients (a mean follow-up of 39.8 months) and 42 ACDF patients (37.6 months) with preoperative reversible kyphosis were included. Both groups had significant improvements in clinical outcomes, without statistically significant differences. Before surgery, there was no significant difference in cervical alignment and ROM between groups. After surgery, both groups had a significant increase in C2-7 angle and FSU without significant inter-group differences. At the last follow-up, CDA group consisted of 5 cases of lordosis, 11 cases of kyphosis and 22 cases of straight spine, while the corresponding case number in ACDF group was 4, 12 and 26 (P = 0.866). The C2-7 ROM was preserved in both groups. The segmental ROM of CDA group decreased mildly from 8.3° preoperatively to 5.1° finally, whereas the segmental ROM of ACDF group decreased significantly to nearly zero. 60.5 % (23/38) patients in CDA group developed HO with 9 levels of grade Ⅲ and 3 levels of grade Ⅳ.

CONCLUSION

For the patients with single-level disc degenerative disease and preoperative reversible kyphosis, both CDA and ACDF achieved satisfactory and comparable clinical results. CDA was non-inferior to ACDF regarding the radiological outcomes of cervical alignment. Patients in CDA group had a relatively high incidence of HO formation.

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.

Cervical Sagittal Alignment: Literature Review and Future Directions

Cervical alignment as a concept has come to the forefront for spine deformity research in the last decade. Studies on cervical sagittal alignment started from normative data, and expanded into correlation with global sagittal balance, prognosis of various conditions, outcomes of surgery, definition and classification of cervical deformity, and prediction of targets for ideal cervical reconstruction. Despite the recent robust research efforts, the definition of normal cervical sagittal alignment and cervical spine deformity continues to elude us. Further, many studies continue to view cervical alignment as a continuation of thoracolumbar deformity and do not take into account biomechanical features unique to the cervical spine that may influence cervical alignment, such as the importance of musculature connecting cranium-cervical-thoracic spine and upper extremities. In this article, we aim to summarize the relevant literature on cervical sagittal alignment, discuss key results, and list potential future direction for research using the '5W1H' framework; "WHO" are related?, "WHY" important?, "WHAT" to evaluate and "WHAT" is normal?, "HOW" to evaluate?, "WHEN" to apply sagittal balance?, and "WHERE" to go in the future?

Neutral cervical sagittal vertical axis and cervical lordosis vary with T1 tilt

OBJECTIVE

The authors conducted a study to determine whether a change in T1 tilt results in a compensatory change in the cervical sagittal vertical axis (SVA) in a cadaveric spine model.

METHODS

Six fresh-frozen cadavers (occiput [C0]-T1) were cleaned of soft tissue and mounted on a customized test apparatus. A 5-kg mass was applied to simulate head weight. Infrared fiducials were used to track segmental motion. The occiput was constrained to maintain horizontal gaze, and the mounting platform was angled to change T1 tilt. The SVA was altered by translating the upper (occipital) platform in the anterior-posterior plane. Neutral SVA was defined by the lowest flexion-extension moment at T1 and recorded for each T1 tilt. Lordosis was measured at C0-C2, C2-7, and C0-C7.

RESULTS

Neutral SVA was positively correlated with T1 tilt in all specimens. After increasing T1 tilt by a mean of 8.3° ± 2.2°, neutral SVA increased by 27.3 ± 18.6 mm. When T1 tilt was reduced by 6.7° ± 1.4°, neutral SVA decreased by a mean of 26.1 ± 17.6 mm.When T1 tilt was increased, overall (C0-C7) lordosis at the neutral SVA increased from 23.1° ± 2.6° to 32.2° ± 4.4° (p < 0.01). When the T1 tilt decreased, C0-C7 lordosis at the neutral SVA decreased to 15.6° ± 3.1° (p < 0.01). C0-C2 lordosis increased from 12.9° ± 9.3° to 29.1° ± 5.0° with increased T1 tilt and decreased to -4.3° ± 6.8° with decreased T1 tilt (p = 0.047 and p = 0.041, respectively).

CONCLUSIONS

Neutral SVA is not a fixed property but, rather, is positively correlated with T1 tilt in all specimens. Overall lordosis and C0-C2 lordosis increased when T1 tilt was increased from baseline, and vice versa.

Posterior Occipitocervical Fusion for Unstable Upper Cervical Trauma in Old and Elderly Population, Although Decreases Upper Cervical Rotation, Does Not Significantly Increase Neck Disability Index

Background

Despite the research progress in the thoraco-lumbo-pelvic balance, cervical spine balance has only recently gained increasing interest. To our knowledge, there is a lack of research regarding sagittal occipitocervical spine balance restoration following posterior occipitocervical fusion (POCF).

Purpose

The primary outcome measure is the evaluation of sagittal cervical alignment roentgenographic parameters and the secondary is the functional outcome (NDI), following POCF for upper (C1 & C2) cervical trauma (UCT) in coexistence with upper cervical spine degeneration. Patients and Methods. Twenty old and elderly patients aged 62 ± 12 years with evident upper cervical degeneration, who received POCF for upper C1 & C2 unstable cervical spine injuries, were included. C2-C7 lordosis, C2-C7 SVA, spinocranial angle (SCA), T1-slope, neck tilt (NT), thorax inlet angle (TIA), cervical tilt (CT), cranial tilt (CrT), and C0-C1 angle were measured. The subfusion angle was used to study the behavior of the unfused cervical segments below fusion. The Neck Disability Index (NDI) was used for the functional outcome evaluation. 29 age-matched individuals were used as controls for radiographic analysis and self-reported functional status comparison.

Results

The roentgenographic data were measured 3 and 39 ± 12 months postoperatively. Twelve patients showed no disability, and eight showed mild disability. Postoperatively, the patients stood with less C2-C7 lordosis, SCA, and CT (P < 0.02) but with higher NT (P < 0.02) in comparison to the controls. The patient's neck disability (NDI) was increasing as TIA increases (P=0.023). Subfusion angle seems to adapt to C2-C7 lordosis (P < 0.0033) and C0-C2 angle (P < 0.003) without any changes till the last evaluation.

Conclusions

POCF sufficiently restored occipitocervical sagittal balance along with functional outcome similar to controls in adult and elderly individuals with evident upper cervical degeneration. We do not recommend POCF for young active individuals without occipitocervical pathology, but in contrary, we recommend the removal of the spinocranial connection hardware after cervical fusion is completed.

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.

Cervical kyphosis in asymptomatic populations: incidence, risk factors, and its relationship with health-related quality of life

Background

Cervical kyphosis has been pointed out in asymptomatic populations. The purposes of this study were (1) to investigate the incidence of cervical kyphosis in asymptomatic populations, (2) to identify risk factors related to cervical kyphosis, and (3) to assess the relationship between cervical kyphosis and health-related quality of life (HRQOL).

Methods

A cohort of 235 asymptomatic volunteers’ records was retrospectively analyzed. Radiographic parameters of the coronal and sagittal planes were measured in the full-length spine x-ray. All patients were classified into two groups based on the cervical lordosis angle: cervical lordosis (CL) and cervical kyphosis (CK). HRQOL was evaluated by EQ-5D and SF-36 (PCS and MCS) questionnaires.

Results

CK was observed in 90 of 235 (38.3%) participants. There was a significant difference with regard to age between volunteers with CK and CL (32.23 ± 8.12 vs. 42.12 ± 6.14, p < 0.05). Several parameters had a significant relationship with CK, including TK, T1 slope, TIA, SVA, and CT. Logistic regression analysis identified age, TK, T1 slope, and SVA as independent risk factors of CK. In addition, there was a negative correlation between CK and the parameters of HRQOL (EQ-5D, − 0.63; PCS, − 0.68; MCS, − 0.59).

Conclusions

The incidence of CK in normal populations is 38.3%. Some spinal parameters are related to CK. CK is associated with the HRQOL.

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.

Ossified Posterior Longitudinal Ligament Existing at an Intervertebral Level Limits Compensatory Mechanism of Cervical Lordosis after Muscle-Preserving Selective Laminectomy

Introduction

As C7 slope increases, lordotic change of C2-C7 angle compensates for adjustments in cervical sagittal balance. However, ossification of the posterior longitudinal ligament (OPLL) may affect the compensatory mechanism of the cervical spine. This study aims to evaluate the impact of OPLL on cervical lordotic compensation after muscle-preserving selective laminectomy (SL).

Methods

This study involved 235 patients with cervical spondylotic myelopathy (CSM) and OPLL who underwent ≥ 3 consecutive levels of SL. OPLL was classified into continuous, segmental, mixed, or localized type on the basis of the criteria previously reported. In this study, based on the motion preservation at the intervertebral level, patients were divided into CSM (n = 114), OPLL segmental type (OPLL-S; n = 44), and other types of OPLL (OPLL-O; i.e., continuous, mixed, and localized; n = 77). The cervical sagittal alignment, degree of spinal cord decompression, and surgical outcomes were compared among the three groups.

Results

The OPLL-O group had a larger postoperative C7 slope (p = 0.020), larger pre- (p = 0.021) and postoperative (p = 0.001) C2-C7 sagittal vertical axis, and greater pre- (p = 0.034) and postoperative (p = 0.002) C7 slope minus C2-C7 angle. Narrower postoperative spinal cord clearance (PSCC) from OPLL (p < 0.001) and more residual spinal cord compression (p < 0.001) were observed in the OPLL-O group. Correlation between postoperative C7 slope minus C2-C7 angle and PSCC was detected (r = −0.238, p < 0.001). The recovery rate of the Japanese Orthopedic Association score was slightly lower in the OPLL-O group (p < 0.001), and it was correlated with postoperative residual spinal cord compression (r = −0.305, p < 0.001).

Conclusions

OPLL-O limits cervical lordotic compensation, resulting in cervical sagittal balance mismatch. It affects the degree of spinal cord decompression, which might be related to surgical outcome.

Factors Associated with Neck and Shoulder Pain in Volunteers

Introduction

The aims of the present study were 1) to examine the association between neck and shoulder pain (NSP) and lifestyle in the general population and 2) to examine if sagittal spino-pelvic malalignment is more prevalent in NSP.

Methods

A total of 107 volunteers (mean age, 64.5 years) were recruited in this study from listings of resident registrations in Kihoku region, Wakayama, Japan. Feeling pain or stiffness in the neck or shoulders was defined as an NSP. The items studied were: 1) the existence or lack of NSP and their severity (using VAS scale), 2) Short Form-36 (SF-36), 3) Self-Rating Questionnaire for Depression (SRQ-D), 4) Pain Catastrophizing Scale (PCS), 5) a detailed history consisting of 5 domains as being relevant to the psychosocial situation of patients with chronic pain, 6) A VAS of pain and numbness to the arm, and from thoracic region to legs. The radiographic parameters evaluated were also measured. Participants with a VAS score of 40 mm or higher and less were divided into 2 groups. Association of SF-36, SRQ-D, and PCS with NSP were assessed using multiple regression analysis.

Results

In terms of QoL, psychological assessment and a detailed history, bodily pain in SF-36, SRQ-D, and family stress were significantly associated with NSP. A VAS of pain and numbness to the arm, and from thoracic region to legs, was significantly associated with NSP. There were no statistical correlations between the VAS and radiographic parameters of the cervical spine. Among the whole spine sagittal measurements, multiple logistic regression analysis showed that sacral slope (SS) and sagittal vertical axis (SVA) were significantly associated with NSP.

Conclusion

In this study, we showed the factors associated with NSP. Large SS and reduced SVA were significantly associated with NSP, while cervical spine measurements were not.