Cranial Tilt Research Articles

A Preliminary Diagnostic Model for Forward Head Posture among Adolescents Using Forward Neck Tilt Angle and Radiographic Sagittal Alignment Parameters.

Despite numerous attempts to correct forward head posture (FHP), definitive evidence-based screening and diagnostic methods remain elusive. This study proposes a preliminary diagnostic methodology for FHP, utilizing a noninvasive body angle measurement system as a screening test for FHP and incorporating radiological parameters for sagittal alignment. We enrolled 145 adolescents for FHP screening. The forward neck tilt angle (FNTA), defined as the angle between the vertical line and the line connecting the participant's acromion and tragus, was measured using the POM-Checker (a noninvasive depth sensor-based body angle measurement system). A whole-spine standing lateral radiograph was obtained, and eight sagittal alignment parameters were measured. Statistical analyses of the association between the FNTA and eight sagittal alignment parameters were conducted. We used 70% of the participant data to establish a preliminary diagnostic model for FHP based on FNTA and each sagittal alignment parameter. The accuracy of the model was evaluated using the remaining 30% of the participant data. All radiological parameters of sagittal alignment showed weak statistical significance with respect to FNTA (best case: r = 0.16, p = 0.0500; cranial tilt). The proposed preliminary diagnostic model for FHP demonstrated 95.35% agreement. Notably, the model using FNTA without radiological parameters accurately identified (100%) participants who required radiographic scanning for FHP diagnosis. Owing to the weak statistical significance of the association between radiological parameters and external body angle, both factors must be considered for accurate FHP diagnosis. When a clear and severe angle variation is observed in an external body angle check, medical professionals should perform radiographic scanning for an accurate FHP diagnosis. In conclusion, FNTA assessment of FNTA through the proposed preliminary diagnostic model is a significant screening factor for selecting participants who must undergo radiographic scanning so that a diagnosis of FHP can be obtained.

Correlation and reliability of cervical sagittal alignment parameters between plain radiographs and multipositional MRI images.

A retrospective study. To assess the validity and reliability of cervical sagittal alignment parameters from multipositional magnetic resonance imaging (MRI) and dynamic cervical radiography. Hospital in Suzhou, China. Patients who underwent both multipositional MRI and dynamic plain radiography of the cervical spine within a 2-week interval between January 2013 and October 2021 were retrospectively enrolled in this study. The C2-7 angle, C2-7 cervical sagittal vertical axis (C2-7 SVA), T1 slope (T1S), cervical tilt, cranial tilt, and K-line tilt were measured in three different positions (neutral, flexion, and extension) with multipositional MRI and dynamic radiography. Inter- and intraobserver reliabilities were assessed by intraclass correlation coefficients (ICCs). Pearson correlation coefficients were used for statistical analyses. A total of 65 (30 males and 35 females) patients with a mean age of 53.4 years (range 23-69 years) were retrospectively enrolled in this study. Significant positive correlations were noted regarding all parameters between the plain radiographs and multipositional MRI images. Inter- and intraobserver reliabilities were excellent for all cervical sagittal alignment parameters measured in the two imaging modalities. All cervical sagittal parameters had significant positive correlations with those from multipositional MRI in all three positions (p < 0.05). Pearson correlation coefficients demonstrated moderate and strong correlations between the two examinations. Cervical sagittal alignment parameters measured on multipositional MRI could reliably substitute for those measured on plain radiographs. Multipositional MRI is a valuable, radiation-free alternative for diagnostic evaluation in degenerative cervical diseases.

Cervical Sagittal Alignment in Patients With Basilar Invagination.

Retrospective study. To present a morphological map of cervical sagittal alignment in basilar invagination (BI), a congenital anomaly of the craniovertebral junction, and contribute to a comprehensive understanding of cervical sagittal alignment in congenital cervical deformities. Ideal cervical sagittal alignment and surgical targets are debated by scholars. However, most of the literature focuses on the description of cervical sagittal alignment in acquired cervical diseases and normal subjects and few on congenital cervical spine deformities. This study analyzed cervical spine lateral radiographs of 87 BI patients and 98 asymptomatic subjects. They were analyzed for cranial, cervical spine, and thoracic inlet parameters. Patients with BI manifested significantly larger values for the following parameters than asymptomatic subjects: cranial tilt, cranial incidence angle, sagittal vertical axis (SVA) CGH-C7, C2-C7 angle, cervical tilt, and significantly smaller values for the following parameters: cranial slope, C0-C2 angle, C0-C7 angle, SVA C2-C7, spine tilt, thoracic inlet angle, and neck tilt. In the BI group, SVA C2-C7 was the cervical parameter most strongly correlated with the cranial, cervical spine, and thoracic inlet parameters, and was smaller in BI patients with fusion (atlanto-occipital assimilation) than in those without. A significant difference was observed between BI patients and asymptomatic subjects. BI patients have craniums tilted forward and downward, smaller upper cervical lordosis, larger lower cervical lordosis, and smaller thoracic inlet angle. In BI patients, the SVA C2-C7 is an important parameter in cervical sagittal alignment. In both individuals with congenital anomalies of the craniovertebral junction and the asymptomatic population, cervical spine alignment is significantly associated with cranial alignment, particularly thoracic inlet alignment.

Simulating upright cervical lordosis in the supine position.

Cervical alignment or lordosis evolution is still attained by direct radiography in standing position because an ideal cervical curvature is essential to maintain a horizontal gaze with minimal energy consumption. However, upright cervical lordosis changes in supine position. Anterior fusion surgery and more sophisticated radiological examinations, such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), are performed in lying position. Therefore, if upright cervical alignment can be simulated in the supine position, true (upright) cervical lordosis can be demonstrated on CT and MRI and also a more proper anterior cervical fusion can be performed in operation with better surgical outcomes. Forty-nine (49) adult patients underwent radiological examinations, including upright cervical radiography and three session of supine MRI in different positions. MRI was performed in (1) conventional neutral supine position, (2) supine position with a 5-cm-high pillow, and (3) supine position with a 10-cm-high pillow under the shoulders. MRI results were analyzed. Wilcoxon, Kolmogorov-Smirnov, and Spearman correlation tests were used to analyze MRI the validity in compared with those of cervical radiography. Cervical lordosis (C2-C7 Cobb angle) of the radiography group was similar to that of supine MRI group using a 5-cm-high pillow, and they have a strong correlation. The T-1 slope from radiography group was similar to and correlated with that of supine MRI groups with both pillows. Cranial tilt measurements of radiography group were different but correlated with the MRI group using a 5-cm-high pillow. Simulating upright cervical lordosis in the supine position is possible by adding a 5-cm- high pillow under the shoulders of the patients. This simulation reduces the need for direct radiography. Anterior cervical fusion surgery performed in this position can provide better surgical results.

The Utility of the Hyperinlet View in Posterior Fixation of Pelvic Ring Injuries.

Percutaneous pelvic fixation has evolved into a widely used, safe, and effective treatment option in the management of pelvic ring injuries. Proper preoperative and intraoperative radiographic evaluation of these injuries is critical to ensure safe placement of fixation of the pelvis. Traditional intraoperative views for posterior pelvic ring fixation include the pelvic inlet and outlet views. We propose that the intraoperative use of a hyperinlet view, which uses additional cranial tilt relative to the traditional inlet view, is helpful to better delineate the spinal canal and thereby better define the posterior limit of the osseous fixation pathway of the upper sacral segments. This study illustrates the use of this novel radiographic view and presents a patient cohort in which it was effectively used.

Cervical and First Thoracic Spine Hounsfield Units Assessment and Relationship to Clinical Outcomes and Cervical Sagittal Parameters in Patients Undergoing Anterior Cervical Spine Surgery

This study had 3 objectives: to compare bone mineral density (BMD) from 3 axial slices, subchondral trabecular bone 2 mm inferior to the cranial endplate, middle of the vertebral body, and subchondral trabecular bone 2 mm superior to the caudal endplate; assess BMD variations and correlations of C1-T1 vertebrae; and correlate BMD with clinical outcomes and cervical sagittal parameters in patients undergoing anterior cervical discectomy and fusion. The study enrolled 71 patients who underwent anterior cervical discectomy and fusion between March 2017 and January 2020. Patient demographics, clinical outcomes, cervical sagittal parameters, and Hounsfield units (HUs) of C1-T1 vertebrae were recorded. Analysis of variance was performed to compare HUs from the axial slices. Pearson correlation coefficient was performed to calculate the relationship between mean HUs of C1-T1 and to assess correlations of mean HUs with clinical outcomes and cervical sagittal parameters. There were no significant differences between HUs of 3 axial levels. Mean HUs were highest in the mid-cervical spine (C4). Significant correlations in mean HUs among all measured spinal levels were observed. Age, sex, and body mass index were not related to mean HUs. Visual analog scale, Neck Disability Index, and Patient Health Questionnaire-9 scores were not related to HUs before and after surgery. There were significant correlations among mean HUs of C2-T1 vertebrae, C2-C7 sagittal vertical axis, and cranial tilt. Mean HUs of C4 had the strongest correlation with C2-C7 sagittal vertical axis. To our knowledge, this is the first study of cranial and caudal subchondral trabecular BMD using HUs and comparing them with the middle of the vertebral body and study of correlations between mean HUs of C1-T1 vertebrae and clinical outcomes and cervical sagittal parameters. Correcting C2-C7 sagittal vertical axis and cranial tilt would improve BMD of C1-T1 vertebrae.

Reliability assessment of cervical spine parameters measured on full-body radiographs in asymptomatic subjects and patients with spinal deformity

BackgroundCervical spinal alignment is usually assessed on full-body radiographs allowing for the concomitant evaluation of possible compensatory mechanisms that may occur at any level in the setting of postural malalignment. HypothesisCervical parameters measured on full-body radiographs are reliable. Patients and methodsA total of 70 subjects were included and divided in 3 groups: asymptomatic adults (n=21), adolescents with idiopathic scoliosis (n=20), and adults with spinal deformity (n=29), for whom full-body low-dose biplanar radiographs were obtained. Eighteen cervical parameters including gaze and cervical curvature, upper cervical spine, global cervical alignment, thoraco-cervical and cervico-pelvic parameters were measured by 4 operators, three times each. The intraclass correlation coefficient (ICC) and the 95% confidence interval (95% CI) where calculated for each parameter and compared between the 3 groups. ResultsICC and the 95% CI were similar between the 3 groups. The measured parameters showed a very high repeatability (ICC>0.8) except for C0-C2, which presented an average repeatability (ICC=0.57). The cSVA, CTPA, C2-SPi, cranial offset, T1-SPi, CBVA and cranial tilt had a 95% CI<2 (° or cm). The TIA, T1-CL and C0-C2 had a 95% CI>6°. DiscussionThe poor visibility of the foramen magnum, hard palate, C7, T1, and the sternum on radiographs could explain why certain parameters showed a higher measurement error. The assessment of these error margins is essential for an accurate evaluation of cervical spinal deformities and a proper therapeutic approach. Level of evidenceIII; retrospective analysis of prospectively collected data.

INTRA- AND INTEROBSERVER REPRODUCIBILITY OF THE RADIOGRAPHIC EVALUATION OF CRANIAL PARAMETERS

ABSTRACT Objective: To evaluate the intra- and interobserver reproducibility of radiographic cranial parameters. Method: A study of the reproducibility of the radiographic cranial parameters (cranial incidence, cranial tilt, cranial slope and spinocervical angle) of 40 patients by 4 observers with different levels of experience. Results: Cranial incidence (CI) showed poor intraobserver concordance; for the other cranial parameters, good to excellent concordance was observed. In the assessment of interobserver concordance, all the parameters analyzed showed statistical significance, with good CI concordance. Conclusion: Cranial parameters are easily reproducible by orthopedists with different levels of experience. CI showed good interobserver concordance, but only reasonable intraobserver concordance among more experienced observers. Level of evidence IV; Diagnostic Study.

Quality of Life in Adult Patients Receiving Cervical Fusion for Fresh Subaxial Cervical Injury: The Role of Associated Spinal Cord Injury.

Purpose To study postoperative Health-Related Quality of Life (HRQOL) after instrumented fusion for fresh subaxial cervical trauma and the effect of spinal cord injury (SCI). Methods From a total of 65 patients, 17 (26%) patients suffered on admission from SCI. Twenty-five patients underwent anterior, 25 posterior, and 15 circumferential cervical surgery for a single cervical injury. Sagittal roentgenographic parameters were measured in 65 age-matched asymptomatic controls and in patients on admission, eight months postoperatively and at final follow-up (lower C2-C7 curvature, cervical sagittal vertical axis (cSVA), spinocranial angle (SCA), T1-slope, neck tilt (NT), thorax inlet angle (TIA), cervical tilt (CT), cranial tilt (CrT), and occiput–C2 angle (C0-C2)). In the last evaluation, SCI patients were compared with their counterparts without SCI using national validated HRQOL instruments (SF-36 and neck disability index (NDI)). Results Fusion included an average of 3 vertebrae (range 2-4 vertebrae). All 65 patients were followed for an average of 5.5 years, (range 3-7 years) postoperatively. In the last evaluation, 10 (15.4%) patients with incomplete SCI improved postoperatively at 1-2 grades. At the last observation, patients with SCI showed poorer HRQOL scores than their counterparts without SCI. In particular, each SF-36 domain score was correlated with SCA, T1-slope, cSVA, and CT. At baseline, patients showed higher NT, CrT, and C0-C2 angle than controls. Eight months postoperatively, cSVA, NT, TIA, and cranial tilt (CrT) were increased in patients. In the last observation, there was difference in the sagittal roentgenographic parameters between patients with SCI compared to those without SCI. Patients aged ≥55 years had postoperatively increased cSVA, NT, and CrT compared to their younger counterparts. Conclusion At the final observation, HRQOL scores were lower in patients with SCI than in their non-SCI counterparts, obviously because of the associated neurologic impairment. SF-36 scores correlated with several sagittal roentgenographic parameters. These correlations should be taken in consideration by spine surgeons when performing cervical spine surgery for fresh cervical spine injuries.

The Effect of Cervical Paravertebral Extensor Degeneration on Sagittal Alignment and Functional Status of Cervical Spine in Patients With Cervical Spondylotic Myelopathy.

This was a cross-sectional study. The objective of this study was to assess cervical paravertebral extensor degeneration in patients with cervical spondylotic myelopathy (CSM) and its impact on the sagittal parameters and functional status of the cervical spine. Paravertebral extensor degeneration is well-studied in CSM; however, the effect of extensor degeneration on the sagittal balance and functional status of the cervical spine is unclear. We enrolled 52 CSM patients (CSM group) and 52 age-matched and sex-matched healthy adults (control group). The C2-C7 and C0-C2 Cobb angles (CAs), C7 slope, T1 slope, cervical arc cord distance, cervical tilt (CERT), cranial tilt (CRAT), and C2-C7 sagittal vertical axis (SVA) were measured. The cross-sectional areas of the deep extensors (DEA), superficial extensors (SEA), and cervical vertebral body (VBA) of C4-C7 were measured. DEA/VBA and SEA/VBA were used to quantify the extensor volume. We analyzed the fatty infiltration ratio of the deep (DFIR) and superficial extensors (SFIR). The Visual Analog Scale, Neck Disability Index, and modified Japanese Orthopaedic Association Scale scores of the CSM group were calculated. The DEA/VBA was significantly lower and the DFIR and SFIR were significantly higher in the CSM group. The C4 DEA/VBA correlated with the C2-C7 SVA, C2-C7 CA, CERT, and the Neck Disability Index and modified Japanese Orthopaedic Association Scale scores (r=-0.608, 0.291, 0.335,-0.649, and 0.409, respectively). The DEA/VBA of C5 correlated with the cervical arc cord distance and CRAT (r=-0.350 and -0.356, respectively). The C4 DFIR correlated with the C2-C7 SVA, C2-C7 CA, and the Visual Analog Scale (r=0.286, -0.297, and 0.429, respectively). The SFIR of C7 correlated with the T1 slope and C7 slope (r=0.368 and 0.319, respectively). Paravertebral extensor degeneration negatively impacts the sagittal sequence and functional status of the cervical spine in CSM patients. Our study provides an insight into understanding the significance of cervical muscular degeneration in CSM patients. Level III.

Impact of cervical sagittal parameters on axial neck pain in patients with cervical kyphosis

BackgroundCervical sagittal alignment (CSA) is closely related with cervical disk degeneration and impacts the spinal function, especially in the setting of cervical kyphosis (CK). In this study, we evaluated the influence of cervical sagittal parameters on the development of axial neck pain (ANP) in patients with CK.MethodsData pertaining to 263 patients with CK who visited the outpatient department of our hospital between January 2012 and December 2018 were retrospective analyzed. The most common symptoms of ANP were neck pain, stiffness, or dullness. Visual analog scale (VAS) was used to evaluate ANP. The following radiographic parameters were evaluated: CK types, C2-7 sagittal vertical axis (SVA), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), cranial tilt, and cervical tilt. Sagittal alignment of CK was classified into 2 types: global and regional type. Multivariate logistic regression analysis was performed to identify risk factors for ANP.ResultsPatients who complained of ANP were categorized as ANP group (VAS score ≥ 3; n = 92), while those without ANP were categorized as non-ANP group (VAS score < 3; n = 171). There was no significant between-group difference with respect to age (P = 0.196), gender (P = 0.516), TIA (P = 0.139), NT (P = 0.676), CK type (P = 0.533), cranial tilt (P = 0.332), cervical tilt (P = 0.585), or cervical disk degeneration (P = 0.695). The T1 slope and C2-7 SVA in the ANP group were significantly greater than that in the non-ANP group (P < 0.05). On multivariate logistic regression, C2-7 SVA [odds ratio (OR) 2.318, 95% confidence interval 1.373–4.651, P = 0.003) and T1 slope (OR 2.563, 95% CI 1.186–4.669, P = 0.028) were identified as risk factors for ANP.ConclusionsOur findings suggest a significant effect of cervical sagittal parameters on the occurrence of ANP in patients with CK. Greater T1 slope and larger C2-7 SVA may lead to the development of neck pain.

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.

Is Cervical Sagittal Balance Related to the Progression of Patients with Cervical Spondylotic Myelopathy?

To examine the preoperative patients with cervical spondylotic myelopathy (CSM): (1) whether cervical sagittal parameters are related to the progress of patients with CSM, and (2) whether cervical sagittal parameters can predict disease progression or prognosis in patients with CSM. From 2015 to 2018, 126 preoperative patients with CSM were enrolled. The inclusion criteria included cervical lateral radiograph, flexion (F), extension (E), and some clinical function scores (visual analog score, modified Japanese Orthopedic Association, Neck Disability Index [NDI], the Medical Outcomes Study 36-Item Short-Form Health Survey, Patient Health Questionnaire-9). Health Transition was used to evaluate the patient's disease progress. The following radiographic parameters were measured: (1) C0-C2 lordosis, (2) C2-C7 lordosis, (3) C7 slope, (4) T1 slope, (5) C2-C7 sagittal vertical axis, (6) cervical tilt, (7) cranial tilt, (8) cervical curvature index (CCI), and (9) CCI change constant (CCI-CC). Of the 126 patients, 101 chose surgical treatment. We followed up for 1 year and grouped the patients with the C2-C7 Cobb angle (F) > 29°. We compared the prognosis of the surgical group and the disease progression of the nonsurgical group. In preoperative patients with CSM, modified Japanese Orthopedic Association was positively correlated with cervical tilt (E), cervical tilt (range of motion), and CCI (range of motion). The larger CCI-CC is the only independent risk factor for the NDI increase. High C2-7F, low cervical tilt, and low cervical tilt (F) values are independent predictors of high Health Transition scores. Whether in the surgical group or the nonsurgical group, the recovery of patients with C2-7F > 29° was better than that of patients with C2-7F ≤ 29°. In preoperative patients with CSM, the larger CCI-CC is the only independent risk factor for the NDI increase. When the patient has a C2-C7 Cobb angle (F) > 29°, the patient's condition progresses slowly.

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

BackgroundCervical 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 methodsACDF 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.ResultsFifty-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.ConclusionMulti-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.

Predictive Effect of Cervical Sagittal Parameters on Conservative Treatment of Single-Segment Cervical Spondylotic Radiculopathy

To explore whether the cervical sagittal parameters affect the conservative treatment of single-segment cervical spondylotic radiculopathy and whether the conservative treatment of single-segment cervical spondylotic radiculopathy can be predicted by cervical sagittal parameters. Cervical spondylotic radiculopathy is currently treated with a stepwise approach, and conservative treatment is recommended. However, there is insufficient evidence to support the efficacy of conservative treatment. Between January 2013 and January 2018, 121 patients with single-segment cervical spondylotic radiculopathy were enrolled in this study. The inclusion criteria included complete cervical lateral radiographs. The following radiographic parameters were measured: C0-2 Cobb angle; C2-7 Cobb angle (CL), C7 slope (C7S), neck tilt (NT), thoracic inlet angle (TIA), T1 slope (T1S), C2-7 sagittal vertical axis (SVA), cervical tilt, cranial tilt, and cervical curvature index (CCI). Cervical spine function and quality of life were assessed using a visual analog scale (VAS) and the Neck Disability Index (NDI). According to the therapeutic effect, the patients were divided into group A (effective conservative treatment group) and group B (ineffective conservative treatment group). Effective conservative treatment was defined as conservative treatment for 3 months (1 nonsteroidal analgesic and 1 neurotrophic drug, supplemented by cervical traction and a neck support brace) resulting in a 60% reduction in NDI score. The Pearson correlation coefficient was used to calculate the correlation between each sagittal parameter and functional score. Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were used to determine independent risk factors and critical values. In the effective conservative treatment group (group A), the pretreatment NDI score was significantly positively correlated with the pretreatment VAS score and negatively correlated with CL, C7S, TIA, T1S, cervical tilt, and CCI. In the ineffective conservative treatment group (group B), the pretreatment NDI score was significantly positively correlated with the pretreatment VAS score and NT, and negatively correlated with age, CL, C7S, T1S, cervical tilt, and CCI. Based on logistic regression analysis and ROC curve analysis, we found that a larger C2-7 Cobb angle before treatment was the sole independent risk factor for conservative treatment (P < 0.001). Patients with a C2-7 Cobb angle >7.7° had a greater likelihood of receiving effective conservative treatment. In patients with single-segment cervical spondylotic radiculopathy, a larger C2-7 Cobb angle before treatment was the sole independent risk factor for effective conservative treatment (P < 0.001). Conservative treatment was more likely to be effective when the C2-7 Cobb angle is >7.7°.

Analysis of the Effect of Surgical Treatment for the Patients with Hirayama Disease from the Perspective of Cervical Spine Sagittal Alignment

This study was carried out to analyze the surgical effect of cervical spine sagittal alignment for patients with Hirayama disease (HD). Forty-four subjects were retrospectively analyzed for the parameters of cervical spine sagittal alignment. The case group consisted of 23 patients with HD, whereas the control group consisted of 21 healthy adolescent subjects. Pre- and postoperative cervical spine sagittal parameters of the patients with HD were collected; the cervical sagittal parameters of the healthy adolescent subjects were also collected. Sagittal alignment parameters were compared between the patients with HD and the healthy adolescent subjects, and between the pre- and postoperative parameters for the patients with HD. Forty-four subjects completed the follow-up, with the average follow-up period being 18.0 months. No significant differences were detected between the HD and control groups for clinical parameters (P > 0.05). The preoperative HD group had smaller values compared with the control group in the sagittal parameters of C2-7 cervical lordosis (CL) angle, T1 slope, thoracic inlet angle (TIA), and cervical tilt angle (P < 0.05). For the patients with HD, the preoperative values were smaller compared with the postoperative HD values for the parameters of C2-7 CL angle, T1 slope, and cervical tilt angle (P < 0.05). We found no significant differences between the postoperative patients with HD and the healthy subjects, including C2-7 CL angle, C2-7 sagittal vertical axis, T1 slope, TIA, neck tilt angle, cervical tilt angle, and cranial tilt angle (P > 0.05). Patients with HD have sagittal imbalance of the cervical spine compared with age-matched healthy adolescent subjects, and surgical treatment could correct the sagittal imbalance.

The Impact of Cervical Spinal Muscle Degeneration on Cervical Sagittal Balance and Spinal Degenerative Disorders.

This is a retrospective analysis of kinematic magnetic resonance images (kMRI). To assess the association of cervical paraspinal muscle with cervical sagittal balance and degenerative spinal disorders. Although the effects of spinal disorders and cervical imbalance on patient's symptoms have been well described, the relationship of the cervical muscle quality and volume to cervical imbalance or spinal disorders is not well established. In total, 100 kMRI taken in a neutral weight-bearing position were analyzed. The adjusted cross-sectional area ratio (aCSA ratio: the value of muscle CSA divided by the vertebral CSA) and fat infiltration ratio of the transversospinalis muscles at C4 and C7 vertebral levels were measured using axial slice of kMRI. The correlation with cervical balance parameters [Oc-C2 angle, C2-C7 angle, C7-T1 angle, C7 slope, T1 slope, cranial tilt, cervical tilt, thoracic inlet angle (TIA), and neck tilt] and cervical degenerative disorders (disk degeneration, Modic change, and spondylolisthesis) were evaluated. The aCSA ratio at C4 correlated with C2-C7 angle (r=0.267), C7 slope (r=0.207), T1 slope (r=0.221), disk degeneration at C3-4, C4-5, C5-6 (r=-0.234, -0.313, -0.262) and spondylolisthesis at C3 (anterior: r=-0.206, posterior: r=-0.249). The aCSA ratio at C7 correlated with disk degeneration at C3-4, C4-5, C5-6, C6-7 (r=-0.209, -0.294, -0.239, -0.209). The fat infiltration ratio at C4 correlated with TIA (r=0.306) and neck tilt (r=0.353), likewise the ratio at C7 correlated with TIA (r=0.270) and neck tilt (r=0.405). All correlations above were statistically significant with P<0.05. The paraspinal muscle volume showed significant relationship with the cervical balance parameters and disk degeneration. While, paraspinal muscle quality related to the thoracic inlet parameters. Our findings can be an important step to develop the knowledge of the association between cervical muscle and cervical degenerative disorders, as well as the sagittal balance of the cervical spine. Level III.

Can C2-6 Cobb Angle Replace C2-7 Cobb Angle?: An Analysis of Cervical Kinetic Magnetic Resonance Images and X-rays.

Retrospective study of consecutive 113 cervical kinetic magnetic resonance images (kMRIs) and 57 radiographs. To elucidate the relationship between C2-6 or C2-7 Cobb angle and cervical sagittal alignment parameters using kMRI, and evaluate the visibility of C6 and C7 inferior endplates on cervical radiographs. Several studies have used C2-6 Cobb angle instead of C2-7 Cobb angle as C7 inferior endplate is not always visible because of overlying shadows. However, the relationship between C2-6 or C2-7 Cobb angle and cervical sagittal alignment parameters remains unclear. Moreover, visibility of C6 inferior endplate remains unknown. C2-6 Cobb angle, C2-7 Cobb angle, occiput-C2 angle, Atlas-dens interval (ADI), narrowest oropharyngeal airway space (nPAS), cervical sagittal vertical axis (cSVA), cervical tilt, cranial tilt, neck tilt, thoracic inlet angle (TIA), and T1 slope were measured using kMRI, and analyzed for their relationship with C2-6 or C2-7 Cobb angle. Visibility rates of C6 or C7 inferior endplates were evaluated using cervical radiographs. Linear regression analysis showed high association between C2-6 and C2-7 Cobb angle (R = 0.696, P < 0.01). C2-6 Cobb angle was significantly correlated with occiput-C2 angle, TIA, T1 slope, neck tilt, cSVA, and cervical tilt; but not with nPAS, ADI, and cranial tilt. C2-7 Cobb angle resembled C2-6 Cobb angle regarding the relationships with other parameters. In our study, 94.7% C6 and 50.9% C7 inferior endplate were clearly visible; 1.8% C6 and 24.6% C7 inferior endplate were invisible. Chi-square test and residual analysis showed significant difference between the two groups (P < 0.01). C2-6 Cobb angle highly resembled C2-7 Cobb angle regarding its relationships with parameters of craniovertebral, cervical and thoracic inlet alignment. C2-6 Cobb angle could be an alternative to C2-7 Cobb angle because of its significantly higher visibility rate. 3.

Regression models of individual cephalometric indicators used in the method of E.P. Harvold

Many scientific studies have shown the superiority of the Harvold method when performing linear measurements for both the upper and lower jaw. The purpose of the work is to construct and analyze the regression models of teleroentgenographic indices used in the method of E.P. Harvold young men and women with normal occlusion close to orthognathic bite and harmonic face. The analysis of lateral teleroentgenograms of 38 young men (aged from 17 to 21) and 55 young women (aged from 16 to 20 years) with normal occlusion close to orthognathic bite and harmonic face, obtained using the Veraviewepocs 3D device, Morita (Japan), was performed according to the techniques of R.M. Ricketts, C.J. Burstone, E.P. Harvold. In the course of the study, all the indicators of the above methods, were divided into three groups: 1 – metric characteristics of the skull, which usually do not change during surgical and orthodontic treatment; 2 – indicators of the tooth-jaw system that allow people with already formed bone skeleton to change the width, length, angles and position of the bones of the upper and lower jaws; 3 – indicators that characterize the position of each individual tooth relative to each other, to the bony cranial structures and face profile. In the licensed package “Statistica 6.0”, regression models were constructed for the following parameters included in the second group, depending on the parameters of the first group: ANS-Сond (maxillary length in the Harvold method described as TM-ANS), Pog-Cond (mandibular length in the E.P. Harvold method is indicated as TM-PGN), Max-Mand – (difference in jaw lengths); as well as the index included in the third group, depending on the indicators of the first and second groups – Ap1uAp1l-DOP (angle Ap1uAp1l-DOP). In the young men, all three possible reliable models of teleroentgenographic parameters were constructed using the E.P. Harvold method, which were included in the second group, depending on the indicators of the first group (R2 = from 0.616 to 0.940), and in young women only the length of the upper and lower jaws (R2=0.857 and 0.792). In both young men and women, all models of the second group of models built according to the indicators of the first group included the distance P-PTV. Up to two models for young men and one model for young women included the distance Pt-N. Also, one model for young men and women included the angle of the cranial tilt (POr-NBa). Only young women have models for the front length of the skull base (N-CC). As for young men and women, we also built a reliable model of the third group indicator, depending on the indicators of the first and second groups (the angle Ap1uAp1l-DOP) (respectively, R2=0.626 and R2=0.584). And in young men and women, the size of the distance A-B is included to the constructed regression equations. In addition, in young men, the regression equation includes the value of the distance P-PTV; while in young women - the angles of the ANS-Xi-PM, MeGo-NPog and N-CF-A, as well as the difference in jaw lengths Max-Mand.

Acceptable Chin–Brow Vertical Angle for Neutral Position Radiography: Preliminary Analyses Based on Parameters of the Whole Sagittal Spine of an Asymptomatic Chinese Population

We sought to acquire the whole sagittal spine parameters and investigated the acceptable chin-brow vertical angle (CBVA) for neutral position radiography in an asymptomatic Chinese population. The parameters measured in 257 asymptomatic volunteers included CBVA, occipital slope, orbital tilt, occipital incidence, C0-C2 Cobb angle, C2-C7 Cobb angle, C1-C7 Cobb angle, C2-C7 sagittal vertical axis and absolute rotation angle, cervical tilt, cranial tilt, T1 slope, and thoracic kyphosis, and others. We used Pearson correlation analyses to find relationships between CBVA and other variables. The subjects were divided into 5 groups according to the CBVA percentile: group A, 0%-20% CBVA; group B, 20%-40% CBVA; group C, 40%-60% CBVA; group D, 60%-80% CBVA; and group E, 80%-100% CBVA. We used analysis of variance to analyze differences among the 5 groups. Orbital tilt, Occipital incidence, C1-C7 Cobb angle, C2-C7 sagittal vertical axis, and cranial tilt all increased with increasing CBVA (P < 0.001). The occipital slope, C2-C7 Cobb angle, C2-C7 absolute rotation angle, cervical tilt, T1 slope, and thoracic kyphosis decreased with decreasing CBVA (P < 0.05). No correlations between other sagittal parameters and the CBVA were found. A slight deviation was found in groups B-D, with a greater deviation in groups A, C, and E. An acceptable range of-1.5° to 5.8° is recommended for the CBVA for cervical radiography in the neutral position. When spinal surgeons evaluate the cervical plane, the effects of the CBVA deviation on cervical curvature must be considered.