Cervical Sagittal Parameters Research Articles

Relationship between Sagittal Alignment and Anterior Bony Resorption of Cervical Vertebral Body in Patients with Ankylosing Spondylitis.

Study DesignThis is a retrospective comparative cohort study.PurposeTo investigate the prevalence of anterior resorption of the cervical spine in ankylosing spondylitis (AS) and its relationship with sagittal alignment.Overview of LiteratureThis study believes that no published reports exist regarding the relationship between anterior resorption and spinopelvic alignment.MethodsThis retrospective study included 238 patients with AS who underwent surgical correction for thoracolumbar kyphosis. Of these, 80 patients with complete subaxial ankylosis were selected and divided into two groups: groups 1 (consisting of 28 patients with anterior bony resorption) and 2 (consisting of 52 patients without anterior resorption). Cervical sagittal parameters were analyzed and compared between the two groups.ResultsThe average lateral diameter measured in patients with C5 anterior resorption was 84.2%±7.8% (62.4%–96.8%). Cervical lordosis was 8.7° ±13.4° and 10.9°±11.5° in groups 1 and 2 (p=0.556), respectively. No significant differences were noted between the two groups on spinopelvic alignment in the T1 slope (52.2°±11.1° and 53.3°±9.9° in groups 1 and 2, respectively; p=0.742), C2–C7 sagittal vertical axis (SVA; 6.2±1.7 cm and 6.2±1.8 cm in groups 1 and 2, respectively; p=0.978), C7 SVA (14.3±4.9 cm and 14.6±6.2 cm in groups 1 and 2, respectively; p=0.823), or T1 pelvic angle (27.1°±8.9° and 31.6°±11.2° in groups 1 and 2, respectively; p=0.382). Correlation analyses were significant between the extent of anterior resorption and sagittal parameters, C2–C7 lordosis (R2=−0.428, p=0.021), and T1–T4 kyphosis (R2=−0.375, p=0.045).ConclusionsAnterior bony resorption could develop by stress concentration. However, the development was not related to the sagittal alignment. The particular segments involved in developing anterior resorption varied, possibly because of their dependence on the preceding pattern of ankylosis.

ANALYSIS OF CERVICAL SAGITTAL PARAMETERS IN PATIENTS WITH RHEUMATOID ARTHRITIS

ABSTRACT Objective: To analyze the cervical sagittal parameters of patients with rheumatoid arthritis (RA) and compare them with the parameters obtained from healthy patients in a sample of the Brazilian population. Methods: Epidemiological data were collected and 72 radiographs of the cervical spine in the sagittal plane were evaluated by measuring the cervical sagittal parameters COG-C7 (distance measured between the center of gravity of the head and the C7 plumb line -cranial offset), C2-C7 lordosis (vertebrae from C2 to C7), T1S (T1 slope), TIA (thoracic inlet angle) and NT (neck tilt). Statistical analysis was performed using the Student’s t and chi-square tests. Results: The TIA and NT values in the RA group were 88.8° ± 12.6° and 54.5° ± 9.3°, respectively, while for the control group, they were 77.7° ± 7.9° and 50.5° ± 7.7°, respectively, the RA group values being statistically higher than the control group values (p <0.001 and p = 0.050, respectively). The values obtained for COG-C7, C2-C7 lordosis and T1S for the RA group were 9.4 ± 16.4mm, 25° ± 22.4° and 2.6° ± 10.1°, respectively, while for the control group they were 11.8 ± 17.6mm, 26.8° ± 12.5° and 30.9° ± 8.4°, respectively. Conclusions: Patients with RA present changes in the thoracic inlet parameters as compared to the control group, with a statistically significant increase in the TIA and NT values, outlining a characteristic compensatory pattern for maintaining cervical sagittal balance. Level of evidence III; Controlled cross-sectional study.

Radiological changes in sagittal parameters after C1-C2 arthrodesis and their clinical correlation: is there a difference between traumatic and non-traumatic causes?

Background Compensatory changes in cervical sagittal alignment after C1-C2 arthrodesis have been reported in a few studies. No studies have explored the differences in these compensatory changes between traumatic and non-traumatic pathologies. Conflicting reports exist on the correlation between cervical sagittal parameters and neck pain or function. Methodology Medical records of 81 consecutive patients [Jan 2010–Dec 2018] who underwent Harms arthrodesis were retrospectively reviewed. 53 patients were included in the final analysis. Radiological parameters [C0-C1, C1-C2, C2-C7 angles and T1 slope] and clinical parameters [VAS (Visual analogue scale) and NDI (Neck disability index)] were compared between the two groups, Group A (traumatic) and Group B (non-traumatic). Results The 53 patients [Group A (n = 24,) and Group B (n = 29)] had a mean age of 49.98 ± 21.82 years (42 males, 11 females). Mean follow up duration was 48.9 months. Δ C1-C2 angle is significantly correlated with ΔC2-C7 angle (Group A, p = 0.004; Group B, p = 0.015) but not with ΔC0-C1 angle (Group A, p = 0.315; Group B, p = 0.938). Though significant improvement in the clinical parameters (VAS/NDI) has been noted in both groups, Group A showed a greater improvement in VAS scores [Group A, (p < 0.001); Group B, (p < 0.023)]. Conclusions The sub-axial sagittal profile was strongly correlated with the ΔC1-C2 angle in both groups. Group B showed greater changes in sagittal parameters after Harms fixation and Group A showed greater improvement in long-term functional outcomes. The final functional outcomes were not related to the initial or final radiological sagittal profile in both groups.

Predictive effect of cervical spinal cord compression and corresponding segmental paravertebral muscle degeneration on the severity of symptoms in patients with cervical spondylotic myelopathy

Previous studies have found that cervical sagittal parameters and spinal cord compression are important risk factors for cervical spondylotic myelopathy (CSM). An increasing number of scholars believe that cervical muscle condition is also one of the factors affecting the severity of symptoms in affected patients. To determine whether: the degree of corresponding segmental paravertebral muscle degeneration is related to the severity of symptoms in patients with CSM; the degree of cervical spinal cord compression can predict the severity of symptoms in patients with CSM. A retrospective study. From January 2015 to January 2019, 121 patients with CSM were enrolled. The visual analog scale (VAS), neck disability index (NDI) and modified Japanese Orthopedic Association (mJOA) were used to assess cervical spinal function and quality of life. From January 2015 to January 2019, 121 patients with CSM were enrolled. The inclusion criterion was the presence of complete cervical lateral radiography and magnetic resonance imaging (MRI) data. The following radiographic parameters were measured: (1) C0-C2 Cobb angle; (2) C2-C7 Cobb angle (CL); (3) T1 slope (T1S); (4) neck tilt (NT); (5) C2-C7 sagittal vertical axis (SVA); and (6) T1S-CL. The following MRI parameters were measured: (1) up(low)-fat/muscle; (2) up(low)-fat/centrum; (3) up(low)-muscle/centrum; (4) cervical cord compression index (CCI); (5) S-index; and (6) cervical spinal cord compression area ratio (S0/S1). The VAS, NDI and mJOA were used to assess cervical spinal function and quality of life. The patients were divided into 2 groups according to the mJOA score: group A (mild-moderate symptom group, mJOA score≥12 points) and group B (severe symptom group, mJOA score<12 points). The Pearson correlation coefficient was used to assess the correlations between cervical sagittal parameters, MRI parameters and functional scores. Logistic regression analysis and ROC curve analysis were performed to identify independent risk factors and critical values. In patients with CSM, the VAS score is positively correlated with NT, up-fat/centrum, S-index and S0/S1. The NDI is positively correlated with NT, up-fat/muscle, up-fat/centrum, S-index, and S0/S1 and negatively correlated with C0-2N and CL. The mJOA score is positively correlated with CL and negatively correlated with C2-7 SVA, CCI, S-index, and S0/S1. Thus, corresponding segmental paravertebral muscle degeneration has relevance to neck pain, but it is not related to limb weakness, neurological dysfunction, gait impairment, sensation or bladder/bowel function dysfunction. Through mJOA score grouping and binary logistic regression analysis, we found that S0/S1 is the only independent risk factor for severe symptoms in patients with CSM. When S0/S1>0.295, the clinical symptoms of patients are more severe. Thus, in clinical practice, when the degree of spinal cord compression exceeds 30%, the clinical symptoms are more severe. In patients with CSM, corresponding segmental paravertebral muscle degeneration has relevance to neck pain, but it does not relate to limb weakness, neurological dysfunction, gait impairment, sensation or bladder/bowel function dysfunction. Cervical spinal cord compression is the only independent risk factor;when the degree of spinal cord compression exceeds 30%, the clinical symptoms are more severe.

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

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. 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. 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). 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.

The Effect of Cervical Fusion on Functional Sagittal Spinal Alignment Based on the Inflection Point: Case Series Study.

A retrospective radiologic study. The inflection point is the disc space between a lordotic and kyphotic segment of spine. To our knowledge, there has been no study evaluating changes in functional sagittal alignment determined by inflection points after cervical fusion surgery. The purpose is to identify changes in functional sagittal alignment after cervical fusion as determined by functional segments between cervicothoracic and thoracolumbar inflection points. Standing radiographs of the sagittal whole spine were taken in 62 patients who underwent cervical fusion procedures. We identified cervicothoracic and thoracolumbar inflection points in the sagittal plane and measured Cobb angles of resulting "functional" cervical, thoracic, and lumbar segments. We also measured the C2 and T1 sagittal vertical axis (SVA) distance to S1 and the anatomic cervical lordosis, thoracic kyphosis, lumbar lordosis, spinopelvic parameters, and T1 sagittal slope. We compared the pre- and post-op values. The functional cervical segment and T1 sagittal slope increased postoperatively. C2 and T1 SVA distance to S1 decreased postoperatively. In patients with a single level fusion or lower instrumented vertebra (LIV) proximal or equal to C6, functional cervical segment, and anatomic cervical lordosis increased postoperatively. In those with multiple level fusion or LIV distal or equal to C7, the C2 SVA distance to S1 decreased postoperatively. After cervical fusion surgery, functional cervical sagittal parameters determined by the inflection point improve without changes in the anatomic sagittal parameters. Postoperative changes in functional sagittal parameters were affected by the number of fused levels and LIV.

Comparison study of clinical outcomes and sagittal alignment improvement between anterior and posterior fusion techniques for multilevel cervical spondylotic myelopathy

To compare the sagittal alignment of different surgical approaches in patients with multiple levels cervical spondylotic myelopathy and explore the relationship between the cervical sagittal alignment and patient's health relative quality of life. A total of 97 multiple levels cervical spondylotic myelopathy patients who underwent surgery from January 2013 to January 2019 were collected in this study. Patients were divided into three groups: anterior cervical discectomy with fusion, anterior cervical corpectomy with fusion and laminectomy with fusion groups. Clinical outcomes and sagittal alignment parameters were compared preoperative and postoperative. There were no significant differences in the average age and sex ratio among the groups. Sagittal parameters correlated to health relative quality of life were C7 slope, occipito-C2 angle, external auditory meatus tilt and cervical sagittal vertical axis. Both anterior cervical discectomy with fusion and anterior cervical corpectomy with fusion groups exhibited better sagittal alignment and clinical outcomes improvement postoperatively. Anterior cervical discectomy with fusion provided better clinical outcomes and the better improvement of cervical lordosis, C7 slope, occipito-C2 angle and cervical sagittal vertical axis compared with patients with Laminectomy with fusion. C7 slope, occipito-C2 angle, external auditory meatus tilt and cervical sagittal vertical axis are the most important cervical sagittal parameters correlated to clinical outcomes in patients with multilevels cervical spondylotic myelopathy; anterior cervical discectomy with fusion and anterior cervical corpectomy with fusion provides more efficient to restoration of cervical sagittal alignment.

Cervical Sagittal Imbalance after Cervical Laminoplasty in Elderly Patients.

Purpose To determine the effect of age on sagittal cervical alignment after cervical laminoplasty procedure so as to identify the group with the greatest degree of variation. Study Setting. Single-center retrospective chart review in a tertiary referral hospital. Outcome Measures. The sagittal vertical axis (SVA) (C2-7), T1 slope, and cervical lordosis. Methods We included patients who underwent cervical laminoplasty between 2014 and 2018 and divided 60 consecutive patients into two groups using the cut-off age of 65 years. The Paired t-test and Mann-Whitney U test were used to compare changes between preoperative radiographic cervical sagittal parameters and those 1 year after surgery. Results Mean patient ages in the older and younger groups were 71 years and 52 years, respectively. The difference of C2-7 SVA was greater in the older group. Conclusion Postoperative cervical balance can be worse when laminoplasty is performed in elderly patients.

The importance of preoperative T1 slope for determining proper postoperative C2\u20137 Cobb\u2019s angle in patients undergoing cervical reconstruction

BackgroundThis study aimed to explore the relationship among different cervical sagittal parameters in asymptomatic volunteers and the correlation between surgical efficacy and difference of presumed and actual postoperative C2–7 Cobbs’s angle (C2–7COBB), which was calculated based on preoperative T1 slope (T1S) in patients undergoing cervical reconstruction.MethodsIn total, 158 inpatients with cervical spondylosis and 274 asymptomatic volunteers were retrospectively reviewed. Cervical sagittal parameters, such as C2–7COBB, T1S, thoracic inlet angle (TIA), and neck tilt (NT), were compared. Then, the correlation among these parameters was analyzed in asymptomatic volunteers, and a regression equation between T1S and C2–7COBB was established and used to analyze the correlation among the Japanese Orthopaedic Association (JOA) score improvement, the sagittal parameters, and the difference between presumed and actual postoperative C2–7COBB in patients after cervical reconstruction.ResultsThe mean T1S, C2–7COBB, and TIA were significantly decreased in patients (P < 0.01). T1S and NT had a strong correlation with TIA (P < 0.01). T1S demonstrated a moderate correlation with C2–7COBB in asymptomatic volunteers (r = 0.569, P < 0.01). A regression equation had been established as C2–7COBB = 0.742 × T1S − 0.866. The mean C2–7COBB and JOA score improved significantly (P < 0.05) postoperatively. Moreover, the JOA improvement rate showed a significant negative correlation with the difference in the presumed and actual postoperative C2–7COBB (r = − 0.696, P < 0.01).ConclusionOur study successfully established a regression equation for calculating postsurgical C2–7COBB based on the correlation between T1S and C2–7COBB in asymptomatic volunteers. The regression equation could be used for guiding surgeons to accomplish an ideal postsurgical C2–7COBB for patients with cervical spondylosis.

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.

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

Retrospective study. To determine the correlations and age-related changes of cervical sagittal parameters in adults without obvious cervical spinal disease. 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. 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. 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. 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. 3.

Cervical sagittal parameters were closely related to Neck Disability Index score after anterior cervical decompression and fusion

BackgroundACDF treatment of CSM is currently recognized as a surgical method with reliable efficacy. However, the cervical radiographic findings in a certain group of patients showed that the symptoms were not completely relieved. This study will investigate the relationship between cervical parameters and prognoses after ACDF surgery.MethodsThis study collected cases of CSM treated with ACDF in Zhongda Hospital from May 2014 to June 2018. The investigators recorded gender, age, cervical sagittal parameters, fusion segment, BMI, symptom duration, and NDI score. To compare the changes of parameters after surgery and explore the correlation between each factor and NDI score.ResultsGenerally, cervical lordosis increased and TS-CL decreased after surgery and during follow-up. Postoperative T1S, SVA and SCA decreased significantly compared to preoperative. T1S was positively correlated with CL (r = 0.245), SVA (r = 0.184), and negatively correlated with SCA (r = − 0.314) and NT (r = − 0.222). The last follow-up NDI score was positively correlated with T1S (r = 0.689), SVA (r = 0.155), TS-CL (r = 0.496), and age (r = 0.194), while negatively correlated with SCA (r = − 0.142). A linear regression model was established with the following formula: NDI = 0.809 × (T1S) − 0.152 × (CL) + 1.962 × (Sex) + 0.110 × (Age). T1S (B = 0.205, P < 0.001), CL (B = − 0.094, P = 0.041), and NT (B = 0.142, P = 0.023) were independent risk factors that affected whether the last follow-up NDI score was greater than preoperative.ConclusionsIn ACDF treatment of CSM, there exists a close correlation between cervical sagittal parameters and NDI scores. T1S, CL, sex, and age were linearly dependent on NDI scores. The increase of T1S, NT, and the decrease of CL were risk factors that affected follow-up NDI score greater than preoperative. Reducing T1S is beneficial to clinical recovery.

Association of complete uncinate process removal on 2-year assessment of radiologic outcomes: subsidence and sagittal balance in patients receiving one-level anterior cervical discectomy and fusion

BackgroundMany patients with cervical radiculopathy experience stenosis of the neural foramens due to cumulative osteophyte or uncovertebral joint hypertrophy. For cervical foraminal stenosis, complete uncinate process resection (UPR) is often conducted concurrently with anterior discectomy and fusion (ACDF). The aim of this study was to assess the clinical and radiological outcomes of ACDF with complete UPR versus ACDF without UPR.MethodsIn total, 105 patients who performed one-level ACDF with a cage-and-plate construct between 2011 and 2015 were retrospectively reviewed. Among them, 37 patients had ACDF with complete UPR, and 68 patients had ACDF without UPR. Radiologic outcomes of disc height, C2–C7 lordosis, T1 slope, C2–C7 sagittal vertical axis (SVA), center of the sella turcica–C7 SVA (St-SVA), spino-cranial angle (SCA), and fusion rate were evaluated on plain X-ray at pre-operation, immediately post-operation, and at 2-year follow-up. For statistically matched pairs analysis, ACDF with UPR group (24 patients) and ACDF without UPR (24 patients) were compared.ResultsAll of the clinical parameters improved at the 2-year follow up (P < 0.0001). Improvement in visual analogue scale (VAS) scores for arm pain was significantly improved in the ACDF with complete UPR group immediately post-operation. All cervical sagittal parameters, including cervical lordosis, segmental angle, disc height, C2-C7 SVA, St-SVA, T1 slope, and SCA, except for preoperative St-SVA, SCA, and disc height of 2 years follow-up, were similar between the ACDF with complete UPR and ACDF without UPR groups. Differences in disc height, C2-C7 SVA, and SCA at 2-year follow up after preoperative examination, however, were statistically significant (p < 0.05). Subsidence occurred in 9 patients (ACDF with complete UPR: 8 cases [33%] versus ACDF without UPR: 1 cases [4%]; p < 0.05).ConclusionsCervical sagittal alignment after ACDF with complete UPR is not significantly different from that achieved with ACDF without UPR. However, subsidence appears to occur more often after ACDF with complete UPR than after ACDF without UPR, although with little to no clinical impact. More precise and careful selection of patients is needed when deciding on additional complete UPR.

Is Facet Joint Distraction Associated with Functional Outcome in Patients with Cervical Spondylotic Radiculopathy Treated with Single-Segment Anterior Cervical Discectomy and Fusion?

To explore 1) whether the degree of facet joint distraction during single-segment anterior cervical discectomy and fusion for cervical spondylotic radiculopathy affects functional outcome and 2) whether the degree of facet joint distraction is related to cervical sagittal parameters. This study retrospectively analyzed data from 72 patients with single-segment cervical spondylotic radiculopathy from January 2013 to December 2018. Lateral cervical radiographs were performed preoperatively and 12months postoperatively. Disc height, interfacet distance, and segmental angle were measured from the lateral cervical radiographs to evaluate facet joint distraction, and cervical sagittal parameters were measured. The outcome measures included visual analog scale (VAS) and Neck Disability Index scores. Sixty-eight patients were included. ΔInterfacet distance was statistically significant in relation to ΔVAS score (P < 0.01). In a receiver operating characteristic curve analysis, less than the mean ΔVAS score for all patients was set as a positive result, and the critical value of Δinterfacet distance was 0.7 mm (P= 0.024, area under the curve= 0.659, sensitivity= 46.8%, specificity= 78.8%). According to the critical value determined by the receiver operating characteristic curve, all patients were divided into the appropriate distraction group or the excessive distraction group. There was a significant difference in VAS scores between the 2 groups (P < 0.05). After undergoing single-segment ACDF for the treatment of cervical spondylotic radiculopathy, patients with an interfacet distance of 0.7 mm or more had worse VAS pain scores. However, this was not related to the improvement in postoperative Neck Disability Index scores; changes in the interfacet distance were not associated with changes in the cervical sagittal parameters.

Influence of extending expansive open-door laminoplasty to C1 and C2 on cervical sagittal parameters

BackgroundFor patients with spinal canal stenosis in the upper cervical spine who undergo C3–7 laminoplasty alone, it remains impossible to achieve full decompression due to its limited range. This study explores the extension of expansive open-door laminoplasty (EODL) to C1 and C2 for the treatment of cervical spinal stenosis of the upper cervical spine and its effects on cervical sagittal parameters.MethodsA retrospective analysis of 33 patients presenting with symptoms of cervical spondylosis myelopathy (CSM) and ossification in the posterior longitudinal ligament (OPLL) of the upper cervical spine from February 2013 to December 2015 was performed. Furthermore, the changes in the C0–2 Cobb angle, C1–2 Cobb angle, C2–7 Cobb angle, C2–7 SVA, and T1-Slope in lateral X-rays of the cervical spine were measured before, immediately after, and 1 year after the operation. JOA and NDI scores were used to evaluate spinal cord function.ResultsThe C0–2 and C1–2 Cobb angles did not significantly increase (P = 0.190 and P = 0.081), but the C2–7 Cobb angle (P = 0.001), C2–7 SVA (P < 0.001), and T1-Slope (P < 0.001) significantly increased from preoperative to 1 year postoperative. In addition, C2–7 SVA was significantly correlated with the T1-Slope (Pearson = 0.376, P < 0.001) and C0–2 Cobb angle (Pearson = 0.287, P = 0.004), and the C2–7 SVA was negatively correlated with the C2–7 Cobb angle (Pearson = − 0.295, P < 0.001). The average preoperative and postoperative JOA scores were 8.3 ± 1.6 and 14.6 ± 1.4 points, respectively, indicating in a postoperative neurological improvement rate of approximately 91.6%. The average preoperative and final follow-up NDI scores were 12.62 ± 2.34 and 7.61 ± 1.23.ConclusionsThe sagittal parameters of patients who underwent EODL extended to C1 and C2 included loss of cervical curvature, increased cervical anteversion and compensatory posterior extension of the upper cervical spine to maintain visual balance in the field of vision. However, the changes in cervical spine parameters were far less substantial than the alarm thresholds reported in previous studies. We believe that EODL extended to C1 and C2 for the treatment of patients with spinal canal stenosis in the upper cervical spine is a feasible and safe procedure with excellent outcomes.

Predictive formula of cervical lordosis in asymptomatic young population

BackgroundNot a large number of previous studies have reported the normal sagittal balance of the cervical spine and physiological cervical lordosis (CL) has not been clearly defined yet.MethodsThis was a prospective radiological analysis of asymptomatic subjects. The following cervical sagittal parameters were measured: CL, thoracic inlet angle (TIA), T1 slope (T1S), neck tilt (NT), and C2–7 sagittal vertical axis (C2–7 SVA). The Pearson correlation test was calculated, and the stepwise multiple regression analysis was conducted by using the CL (dependent variable) and the other cervical sagittal parameters (independent variables) to determine the best sets of predictors. A paired sample t test was conducted between the predicted and measured values.ResultsThe mean age of 307 participants was 24.54 + 3.07. The mean CL, TIA, T1S, NT, and C2–C7 SVA was 17.11° ± 6.31°, 67.87° ± 7.78°, 25.84° ± 5.36°, 42.53° ± 6.68°, and 14.60 ± 8.20 mm, respectively. The formula was established as follows: CL = 0.762 × T1S − 0.392 × C2–C7 SVA + 0.25 × TIA − 13.795 (R = 0.812, R2 = 0.660) (stepwise multiple regression) and CL = 0.417 × TIA − 11.193 (R = 0.514, R2 = 0.264) (simple linear regression). There was no statistical difference between the predicted CL and the measured CL (t = 0.034, P = 0.973).ConclusionsThere was a significant correlation between CL and other cervical sagittal parameters, including TIA, T1S, NT, and C2–C7 SVA in asymptomatic Chinese population. The results of this study may serve as a normal reference value for the study of asymptomatic population.

Can Supine Magnetic Resonance Imaging Be an Alternative to Standing Lateral Radiographs for Evaluating Cervical Sagittal Alignment?

ObjectiveRecently, many studies have reported that cervical alignment is related to clinical outcomes. However, poor visibility of anatomical structures during X-ray (XR) imaging limits accurate measurements. In supine magnetic resonance (MR) imaging, the boundary of the anatomical structure is clear, but the correlation to XR images taken in a standing position is problematic. In this study, we evaluated the agreement of sagittal alignment parameters between MR and XR measurements.MethodsWe retrospectively reviewed 268 patients. Cervical sagittal parameters were measured using XR and MR images, and their relationships were evaluated using Pearson's correlation, paired t-tests, and 2-way random, single score intraclass correlation coefficient (ICCs) (2,1). Using simple linear regression analysis, MR results were converted to the expected value (MR-E). The subsequent comparison of MR-Es with XRs was used to examine whether MR-Es could replace XRs when the measurement difference was less than 2 mm or 2°.ResultsThe correlation between the MR and XR measurements was high, but ICCs showed low reliability. All parameters were significantly different between XR and MR measurements in paired t-tests. Converting the MR values eliminated the t-test differences between MR-Es and XRs, but did not affect correlations and ICCs. The replacement ratio included the Cobb angle: 20.3%, T1: 27.1%, the sagittal vertical axis: 17.6%, C1–2: 29.7%, and C2: 16.0%.ConclusionThese results indicate that supine MR measurements could not replace upright XR measurements.

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.

Posterior open-door laminoplasty secured with titanium miniplates vs anchors: a comparative study of clinical efficacy and cervical sagittal balance

ObjectivePosterior open-door laminoplasty (PODL) is a common procedure for treating multilevel cervical spondylotic myelopathy (MCSM). Little information is available regarding the cervical sagittal balance and surgical efficacy of PODL when securing with different methods. Therefore, this study aims to investigate the clinical outcomes and the changes in cervical sagittal parameters and balance associated with PODL secured with titanium miniplates vs anchors.MethodA retrospective analysis was performed on the clinical data of 79 patients with MCSM who were treated in our institution from January 2015 to December 2016. Among them, 42 patients were treated by PODL secured with titanium miniplates (group A) and 37 patients by PODL secured with anchors (group B). Surgical time, intraoperative blood loss, hospital stay, hospitalized cost, VAS scores of neck pain, JOA scores, neck disability index (NDI), and improvement rate of spinal neurological function (IRNF) were recorded before surgery and at 12 months after surgery. Before surgery, at 1 month and 2 years after surgery, the following radiological parameters were recorded and compared on the lateral cervical X-ray images: the distance from the vertical axis of C2 sagittal plane to the posterior superior edge of C7 (C2-7 SVA), the inclusion angle of tangent between C2 and C7 trailing edge (C2-7 Cobb angle), and the intersection angle between the upper edge of T1 and the horizontal line (T1 Slope).ResultComparing the two groups, there were no significant differences in surgical time, intraoperative blood loss, hospital stay, VAS, JOA, and NDI scores before surgery (P > 0.05); however, the hospitalized cost of group A were much higher than those of the group B (P < 0.05). At 2 years after surgery in the two groups, there was a significant reduction in VAS and NDI scores (P < 0.05), and JOA scores increased significantly (P < 0.05). In addition, there were no significant differences in VAS, JOA and IRNF between the two groups (P > 0.05); however, NDI scores of group A were better than those of group B (P < 0.05). In radiological parameters, before surgery, the two groups showed no significant differences in C2-7 SVA, C2-7 Cobb angle, and T1 slope (P > 0.05); however, after surgery, C2-7 SVA and T1 slope increased (P < 0.05), while C2-7 Cobb angle decreased (P < 0.05). At 2 years after surgery, the two groups did not differ significantly in C2-7 Cobb angle and T1 slope (P > 0.05), while C2-7 SVA of group A was superior to that of group B (P < 0.05). The difference value of C2-7 SVA measured before and after surgery was correlated negatively with that of NDI scores (P < 0.05).ConclusionPODL secured with titanium miniplates or anchors achieved good clinical efficacy in the treatment of MCSM. However, the patients with miniplates feel a better cervical functional status, while those with anchors spend less on hospitalization. Both methods lead to anteversion of cervical spine, but cervical sagittal balance after miniplates is better than that of anchors.