Spino-cranial Angle Research Articles

Differences in cervical sagittal parameters and muscular function among subjects with different cervical spine alignments: a surface electromyography-based cross-sectional study.

We analyzed cervical sagittal parameters and muscular function in different cervical kyphosis types. This cross-sectional study enrolled subjects with cervical spine lordosis (cervical curvature < -4°) or degenerative cervical kyphosis (cervical curvature > 4°), including C-, S-, and R-type kyphosis. We recorded patients' general information (gender, age, body mass index), visual analog scale (VAS) scores, and the Neck Disability Index (NDI). Cervical sagittal parameters including C2-C7 Cobb angle (Cobb), T1 slope (T1S), C2-C7 sagittal vertical axis (SVA), spino-cranial angle (SCA), range of motion (ROM), and muscular function (flexion-relaxation ratio (FRR) and co-contraction ratio (CCR) of neck/shoulder muscles on surface electromyography). Differences in cervical sagittal parameters and muscular function in subjects with different cervical spine alignments, and correlations between VAS scores, NDI, cervical sagittal parameters, and muscular function indices were statistically analyzed. The FRR of the splenius capitis (SPL), upper trapezius (UTr), and sternocleidomastoid (SCM) were higher in subjects with cervical lordosis than in subjects with cervical kyphosis. FRRSPL was higher in subjects with C-type kyphosis than in subjects with R- and S-type kyphosis (P < 0.05), and was correlated with VAS scores, Cobb angle, T1S, and SVA. FRRUTr was correlated with NDI, SCA, T1S, and SVA. FRRSCM was correlated with VAS scores and Cobb angle. CCR was correlated with SCA and SVA. Cervical sagittal parameters differed among different cervical kyphosis types. FRRs and CCRs were significantly worse in R-type kyphosis than other kyphosis types. Cervical muscular functions were correlated with cervical sagittal parameters and morphological alignment.

Effect of Cervical Index Changes on Cervical Pain

Background: The study of the angles between the vertebrae and the curvatures of the spine plays an important role in the pathogenesis of spinal disorders. The nature of the cervical region makes it susceptible to various cervical disorders, many of which can be caused by imbalanced alignment. Methods: In the present study, patients with chronic neck pain were compared with the normal population for cervical indexes. Results: One hundred subjects were selected, including 57 males (57%) and 43 females (43%). Neck tilting was significantly lower in the case group than control (41.5 vs. 45.8) (p=0.01). The mean of C0-C2 angle did not differ between groups (p=0.503), however, a significant increase was found for C2-C7 and C0-C7 angles (p=0.012) and (p=0.05), respectively. Further analysis revealed that cranial offset (21.9 vs. 8.6) and cranial tilting (21.3 vs. 10.1) significantly increased in patients with chronic neck pain (p&lt;0.001) and (p=0.004), respectively. Also, cervical Sagittal Vertical Axis (SVA) has shown a significant increase in patients than control (24.8 vs. 9.7) (p&lt;0.001). Conclusion: The data have indicated that cervical indexes. Thus, spine surgeons should obtain standing cervical radiographs and evaluate the relationship between T1 slope, Spino Cranial Angle (SCA), and cSVA in all cases affected by cervical pathogenesis, even without obvious deformity.

Comparison of radiological and clinical outcomes of cervical laminoplasty versus lateral mass screw fixation in patients with ossification of the posterior longitudinal ligament

PurposeThis study aimed to compare cervical sagittal parameters and clinical outcomes between patients undergoing cervical laminoplasty(CL) and those undergoing lateral mass screw fixation(LMS).MethodsWe retrospectively studied 67 patients with multilevel ossification of the posterior longitudinal ligament (OPLL) of the cervical spine who underwent lateral mass screw fixation (LMS = 36) and cervical laminoplasty (CL = 31). We analyzed cervical sagittal parameters (C2-7 sagittal vertical axis (C2-7 SVA), C0-2 Cobb angle, C2-7 Cobb angle, C7 slope (C7s), T1 slope (T1s), and spino-cranial angle (SCA)) and clinical outcomes (visual analog scale [VAS], neck disability index [NDI], Japanese Orthopaedic Association [JOA] scores, recovery rate (RR), and minimum clinically significant difference [MCID]). The cervical sagittal parameters at the last follow-up were analyzed by binary logistic regression. Finally, we analyzed the correlation between the cervical sagittal parameters and each clinical outcome at the last follow-up after surgery in both groups.ResultsAt the follow-up after posterior decompression in both groups, the mean values of C2-C7 SVA, C7s, and T1s in the LMS group were more significant than those in the CL group (P ≤ 0.05). Compared with the preoperative period, C2-C7 SVA, T1s, and SCA gradually increased, and the C2-C7 Cobb angle gradually decreased after surgery (P < 0.05). The improvement in the JOA score and the recovery rate was similar between the two groups, while the improvement in the VAS-N score and NDI score was more significant in the CL group (P = 0.001; P = 0.043). More patients reached MCID in the CL group than in the LMS group (P = 0.036). Binary logistic regression analysis showed that SCA was independently associated with whether patients reached MCID at NDI postoperatively. SCA was positively correlated with cervical NDI and negatively correlated with cervical JOA score at postoperative follow-up in both groups (P < 0.05); C2-7 Cobb angle was negatively correlated with cervical JOA score at postoperative follow-up (P < 0.05).ConclusionCL may be superior to LMS in treating cervical spondylotic myelopathy caused by OPLL. In addition, smaller cervical SCA after posterior decompression may suggest better postoperative outcomes.

Cervical Sagittal Balance: Impact on Clinical Outcomes and Subsidence in Anterior Cervical Discectomy and Fusion.

Degenerative disease of the cervical spine leads to sagittal imbalance, which may affect treatment results. The purpose of this study was to evaluate changes in selected cervical sagittal balance parameters and their effects on subsidence and clinical outcomes of the procedure. This study encompassed a total of 95 evaluated patients who underwent anterior cervical discectomy and fusion (ACDF). Selected cervical sagittal balance parameters were assessed using lateral projection X-rays: C2-C7 spinal vertical axis (C2-C7 SVA), spinocranial angle (SCA), C7 slope, C2-C7 lordosis, and the segmental Cobb angle. Measurements were collected the day before, the day after, and 12 months after surgery. Changes in clinical parameters was assessed using the VAS and NDI scales. Subsidence was defined as a loss of intervertebral height of more than 30% of the baseline value. Among all the assessed parameters, only the C2-C7 SVA demonstrated a statistically significant difference between the groups with and without subsidence: 26.03 vs. 21.79 [mm], with p = 0.0182, preoperatively and 27.80 vs. 24.94 [mm], with p = 0.0449, on the day after surgery, respectively. We conclude that higher preoperative and postoperative C2-C7 SVA values might contribute to an elevated risk of implant subsidence. Furthermore, both the SCA and C7 slope could conceivably influence the clinical outcome, respectively impacting pain, as assessed by the VAS and the disability, as evaluated through the NDI scale.

Comparison of Cervical Sagittal Parameters among Patients with Neck Pain and Patients with Cervical Spondylotic Radiculopathy and Cervical Spondylotic Myelopathy.

Previous studies have shown that cervical sagittal alignment is strongly associated with cervical deformity, myelopathy, and cervical adjacent-segmental disease, and these cervical sagittal parameters are correlated with health-related quality of life. However, less attention has been paid to cervical sagittal balance in various cervical disorders. This study aimed to compare cervical sagittal parameters between patients with nonspecific neck pain (NS-NP) and patients with cervical spondylotic radiculopathy (CSR) and cervical spondylotic myelopathy (CSM). We retrospectively examined 236 patients from between January 2020 and October 2022. We divided them into three groups (NS-NP, CSR, and CSM) and collected general information and cervical sagittal parameters for these patients. The variation of parameters between the size of these parameters and gender differences was analyzed. Pearson's or Spearman's correlation was applied to analyze the association of cervical sagittal parameters of all patients between the three groups. There were significant differences in age and sex among the three groups (p < 0.001), with the NS-NP group being the youngest and NS-NP being more common in women. The parameters of cervical sagittal position significantly differed among the three groups (p < 0.05). Pearson's or Spearman's correlation result showed that the C2-C7 Cobb angle was negatively associated with the C2-C7 sagittal vertical angle (SVA), and the C2-C7 Cobb angle and T1 slope (T1s) were negatively associated with the spino-cranial angle (SCA). There was a positive correlation between the C2-C7 Cobb angle and C7 slope (C7s), C2-C7 SVA and T1s, C2-C7 SVA and SCA, and C7s and T1s. This study showed that between the three groups, patients with nonspecific neck pain had smaller SCA, and among patients with NS-NP, women had more significant SCA. The smaller anteroposterior diameter of the thorax in women might explain this difference.

The Anteroposterior Positioning of Viscoelastic Cervical Disc Prosthesis Does Not Alter the Outcomes.

While first-generation articulated disc prostheses had an ideal positioning schematically as posterior as possible because of their geometrically determined center of rotation, the dogma may change for viscoelastic implants, whose center of rotation is free. Our hypothesis was to assess whether the anteroposterior positioning (APP) of a viscoelastic implant may influence the clinical or radiological outcomes at follow-up. Twenty-five patients (mean age 47 years) were evaluated, with an average follow-up of 25.9 months. The primary outcome was the implants' APP on lateral radiographs. APP between 0% and 49% meant anterior centering, 50% perfect centering, and 51% to 100% posterior centering. The cohort was divided into 2 groups: anterior positioning and posterior positioning. Measurements were performed blindly to the functional outcomes. Visual analog scale for neck pain and radicular pain and the Neck Disability Index were assessed. Range of motion was measured at the last follow-up. The C2 to C7 Cobb angle and the spinocranial angle were also measured. The median crude offset from the vertebral endplate center was 0.4 mm (mean: 0.3 mm, Q1: -1.5 mm, Q3: 2 mm; range, -2.9 to 4 mm). The mean overall APP was 49%, 45.2% (95% CI, 43.2%-47.1%) in the anterior group, and 54.1% (95% CI, 51.4%-55.3%) in the posterior group. Fifteen patients were in the group anterior positioning and 10 in the group posterior positioning. The mean spinocranial angle was 79° preoperatively and 74° preoperatively (P = 0.04). Functional outcomes were significantly improved at the last follow-up (P < 10-4). There was no significant correlation between the APP, functional outcomes, and range of motion. The APP of the CP-ESP viscoelastic disc arthroplasty does not significantly influence the clinical or radiological outcomes at follow-up. This study suggests that this type of implant tolerates greater variability in its implantation technique.

Extension of decompression to C2 doesn’t affect the spinal sagittal parameters compared with standard open-door laminoplasty

We modified and extended laminoplasty to the upper cervical spine on patients with canal stenosis associated with upper cervical spinal ossified lesions. However, whether the extended decompression range of laminoplasty can cause further effects on cervical stability is rarely studied at present. A retrospective study to analyze the relationship between the surgical levels and cervical sagittal parameters effects was performed in patients with cervical spondylosis myelopathy who had undergone posterior cervical expansive open-door laminoplasty with/without extending to C2. In total, 64 patients were divided into 2 groups according to the surgical levels. Radiologic outcomes of occipito-cervical angle (C0-2 Cobb angle), CL C27 Cobb angle, cervical sagittal vertical alignment, T1-Slope (T1S), T1S minus CL (T1S-CL), spino-cranial angle and center of the sella turcica-C7 SVA (St-SVA) were evaluated on lateral X-rays of the cervical spine at pre-operation, post-operation, and 2-year follow-up. The patient's health-related quality of life was obtained including neck disability index, Japanese orthopaedic association scores, and visual analog scale. Changes in sagittal parameters were observed in both groups after surgery. T1S, cervical sagittal vertical alignment, and T1S-CL significantly increased and CL decreased in 2 groups of patients postoperative. After a 2-year follow-up period, the C0-2 Cobb angle was found to increase compared to preoperative records. In addition, there were no significant differences in spino-cranial angle and st-SVA between preoperative and 2 years follow-up measurements. Health-related quality of life was improved in both groups and was not significantly different. Herein, the parameters indicated a tilting forward of the lower cervical spine and a more lordotic upper cervical spine to maintain a horizontal gaze in patients. However, C2 to 7 laminoplasty was performed to achieve satisfactory clinical results without significantly changing the spinal sagittal parameters.

Relationship between spinocranial angle and clinical outcomes after laminoplasty in patients with ossification of the posterior longitudinal ligament.

The aims of this study were to identify the relationship between the spinocranial angle (SCA) and clinical outcomes and to explore whether the SCA is a suitable indicator to predict clinical outcomes for patients with ossification of the posterior longitudinal ligament (OPLL). Sixty-five patients with cervical OPLL who underwent laminoplasty with at least 24 months of follow-up were selected for the current study and were divided into two groups according to whether the SCA was greater than or less than the mean preoperative SCA. Sagittal alignment changes were compared between the groups. The Pearson correlation coefficient was applied to assess the relationship among sagittal parameters. Univariate and multiple linear regression analyses were applied to identify the relationship between the recovery rate (RR) and radiological parameters. Patients were classified into two groups based on the mean value of preoperative SCA (85.1°). SCA was negatively correlated with T1 slope (T1s) and cervical lordosis (CL) and positively correlated with the C2-7 sagittal vertical axis (cSVA) (p < 0.001). Patients with lower SCA had larger T1s and CL preoperatively and at the follow-up (T1s: p < 0.001; CL: p < 0.001) and showed greater loss of cervical lordosis after laminoplasty (p < 0.001). However, no significant differences in the incidence of kyphosis, Japanese Orthopaedic Association (JOA) or RR were noted between the two groups. Although Pre-SCA, Pre-CL, F/U-CL and Pre-T1sCL were significantly associated with RR, these indicators were not associated with RR in the multivariate regression analysis. Patients with lower SCA tended to have higher T1s and CL before surgery and greater loss of cervical lordosis at the follow-up visit but still maintained a greater lordosis angle. Although preoperative SCA is significantly related to RR, the relationship is not sufficient to indicate that preoperative SCA can be used to predict clinical outcomes. Therefore, further research is needed to confirm the impact of SCA on clinical outcomes for OPLL.

Does the asymmetry and extension function of the preoperative cervical paraspinal extensor predict postoperative cervical sagittal deformity in patients who undergo modified laminoplasty?

BACKGROUND CONTEXTA previous study found that the cross-sectional area (CSA) of the preoperative cervical paraspinal extensors (CPEs) was associated with loss of cervical lordosis after laminoplasty, while a recent study found that CPE asymmetry was associated with symptoms of degenerative cervical myelopathy. Whether preoperative CPE asymmetry can predict cervical sagittal deformity (CSD) after laminoplasty is unknown. PURPOSETo assess whether asymmetry, degree of degeneration, and extension function of the CPE can be used as predictors of postoperative CSD in patients who undergo laminoplasty. STUDY DESIGNA retrospective study. PATIENT SAMPLEFrom January 2017 to December 2019, 55 patients with multilevel cord compression and myelopathic symptoms were enrolled. OUTCOME MEASURESThe 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. METHODSFrom January 2017 to December 2019, 55 patients undergoing modified laminoplasty were included. The following parameters were measured preoperatively and 24 months postoperatively on X-ray: (1) C0–C2 Cobb angle; (2) C2–C7 Cobb angle (CL); (3) T1 slope (T1S); (5) C2–C7 sagittal vertical axis (SVA); (6) T1S minus CL; (7) Preoperative extension function: Extension CL minus Neutral CL (EF). Preoperative global alignment parameters: (8) spino cranial angle, (9) C7-S1 sagittal vertical axis (C7 SVA), (10) pelvic incidence, (11) lumbar lordosis, (12) thoracic kyphosis. (13) Preoperative CPE parameters: Summation of bilateral total cross-sectional area (STCSA), summation of bilateral total cross-sectional area ratio (STCSAR), total cross-sectional area asymmetry, summation of bilateral functional cross-sectional area of muscle (SFCSA), summation of bilateral functional cross-sectional area of muscle ratio (FCSAR), and functional cross-sectional area of muscle asymmetry (FCSAA). The VAS, mJOA, and NDI were used to evaluate cervical spine function and quality of life. Patients were divided into the CSD group and the non-deformed group (N-CSD) group postoperatively, and the parameters between the two groups were compared. The Pearson correlation coefficient was used to evaluate the relationship between the parameters, and multiple regression analysis and ROC curve analysis were used to determine the predictors and key values. RESULTSCompared with functional scores, mJOA in the CSD group was significantly lower than that in the N-CSD group, while NDI and VAS were significantly higher. Postoperative CL was significantly correlated with EF, SFCSA/STCSA (C3–C6), SFCSAR (C4 and C6), STCSAR (C6), and FSCAA (C6). T1S minus CL was significantly correlated with EF, SFCSA/STCSA (C3–4 and C6), SFCSAR (C4 and C6), STCSAR (C6) and FSCAA (C6). C2–7 SVA was significantly correlated with EF, SFCSAR (C4 and C6), STCSAR (C6), and FSCAA (C6). Multiple regression analysis showed that FCSAA (C6), SFCSAR (C6), SFCSAR (C4), and EF were significant predictors of postoperative CSD. ROC curve analysis showed that the optimal cutoff points were 18.405, 2.95, 4.47, and 11.96. CONCLUSIONSThe present study found that preoperative extension dysfunction of CPEs, asymmetry at the C6 level cervical extensors, and cervical extensor CSAs without fatty infiltration at the C4 and C6 levels were associated with cervical sagittal imbalance after modified laminoplasty. These factors can be considered when future spine surgeons formulate surgical plans.

Physiologic Cervical Alignment Change between Cervical Spine X-ray and Computed Tomography.

ObjectiveThe purpose of this study was to investigate the correlations among various radiological parameters used to determine cervical alignment from cervical spine radiographs (X-CS) and cervical spine computed tomography (CT-CS), both within and between modalities. MethodsThis study included 168 patients (≤60 years old) without a definite whole spine deformity who underwent CT-CS and X-CS. We measured occipital slope (O-s), C1 slope, C2 slope, C7 slope, sella turcica - C7 sagittal vertical axis (StC7-SVA), spinocranial angle, T1 slope, and C27-SVA. We calculated the O-C2 angle, O-C7 angle, and C2-7 angle from the measured parameters and conducted correlation analyses among multiple parameters. ResultsThe intrinsic correlation features among multiple cervical parameters were very similar for both X-CS and CT-CS. The two SVA parameters (C27-SVA and StC7-SVA) were mainly influenced by the upper cervical slope parameters (r=|0.13–0.74|) rather than the lower slope cervical parameters (r=|0.08–0.13|). The correlation between X-CS and CT-CS for each radiological parameter was statistically significant (r=0.26–0.44) except for O-s (r=0.10) and StC7-SVA (r=0.11). ConclusionThe correlation patterns within X-CS and CT-CS were very similar in this study. The correlation between X-ray and CT was statistically significant for most radiological parameters, and the correlation score increased when the horizontal gaze was consistently maintained. The lower cervical parameters were not statistically associated with translation-related parameters (C2-7 SVA and StC7-SVA). Therefore, the upper cervical segment may be a better predictor for determining head and neck translation.

Is Complete Correction of Cervical Sagittal Malalignment Necessary During 4-Level Anterior Cervical Discectomy and Fusion Surgery in Patients With Kyphosis?

Retrospective analysis. We investigated whether complete correction of cervical sagittal malalignment is necessary during 4-level anterior cervical discectomy and fusion (ACDF) in patients with kyphosis. This retrospective study included 84 patients who underwent 4-level ACDF surgery at a university hospital between January 2010 and December 2015. Based on the degree of cervical lordosis correction, patients were categorized into the following groups: mild (0-10°), moderate (10-20°), and complete correction (>20°). The clinical outcomes, radiological parameters, and functional outcomes were analyzed. We observed no significant intergroup differences in the baseline characteristics. The cervical sagittal vertical axis (CSVA) correction loss at the final follow-up was lesser in the mild- and moderate- than in the complete-correction group. The spinocranial angle (SCA) and T1 slope (T1 S) were significantly higher in the moderate- and complete-correction groups than in the mild-correction group, 3 days postoperatively. The cervical proximal junctional kyphosis (CPJK), adjacent segment degeneration (ASD), and ASD following CPJK rates were higher in the complete-correction group. We observed no significant intergroup differences in postoperative complications; however, 5 patients showed internal fixation failure in the complete-correction group; 4 of these patients required reoperation. No significant intergroup difference was observed in the Japanese Orthopedic Association and neck disability index scores at any time point. A mild-to-moderate correction of cervical lordosis is superior to complete correction in patients with kyphosis who undergo 4-level ACDF because this approach is associated with lesser axial stress and CSVA correction loss.

Spino cranial angle as a predictor of loss of cervical lordosis after laminoplasty in patients with cervical myelopathy

BackgroundTo explore the relationship between spino cranial angle (SCA) and loss of cervical lordosis (LOCL), and to determine whether SCA has the ability to predict LOCL for patients with cervical myelopathy.MethodsA total of 68 consecutive patients with cervical myelopathy who received laminoplasty (LAMP) were selected to the current study. C2–C7 lordosis was defined as a representation of the cervical alignment. Alignment change > 0° was considered LOCL. Multiple linear regression analysis was applied to evaluate the association between LOCL and various sagittal parameters at preoperative, such as SCA, CL, T1s and cSVA. Linear regression analysis was applied to evaluate the relationships between LOCL and preoperative SCA in each subgroup.ResultsPatients were assigned to three groups depending on the quartile of preoperative SCA. The first quarter of patients were defined as the low SCA group, the last quarter were defined as the high SCA group and the middle half were defined as the middle SCA group. There was no statistically significant difference in age, sex and the type of OPLL among the three groups. Patients in the low SCA group showed more cervical lordosis before surgery and more LOCL after LAMP (p < 0.001). After linear regression analysis for SCA and LOCL, preoperative SCA was negatively correlated with LOCL in the low SCA group (r = − 0.857, p < 0.001) and high SCA group (r = − 0.515, p = 0.034). However, there was no significant correlation between preoperative SCA and LOCL in the middle SCA group (r = 0.027, p = 0.881).ConclusionsPatients with lower SCA had more lordosis preoperatively and performed more LOCL after LAMP at 2 years of follow-up. Both too high or low preoperative SCA were negatively correlated with the degree of LOCL, while when the SCA fluctuates in a suitable range, it is easier to compensate for the changes of cervical sagittal alignment.

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.

Spino Cranial Angle and Degenerative Cervical Spondylolisthesis

The purpose of our study was to analyze and compare the spino cranial angle (SCA) in patients with degenerative cervical spondylolisthesis (DCS) and asymptomatic controls and to determine whether SCA could help diagnose DCS. We enrolled 50 patients diagnosed with DCS (4.3%) from among 1168 patients and the same number of asymptomatic participants as the control group by using cervical radiographs. Both groups underwent cervical radiographs and computed tomography at the same time. Various sagittal parameters were measured on computed tomography in a standardized supine position and compared with the asymptomatic control group. The Spearman correlation coefficient was applied to test the correlation among the sagittal parameters in the DCS group. Multivariate logistic regression analysis and receiver operating characteristic curve analysis were performed to determine whether SCA could help predict DCS. Fifty patients were enrolled in the DCS group, and 50 asymptomatic participants were included in the control group. The SCA was significantly lower for the DCS group than for the control group (76.84 ± 7.48 degrees vs. 82.47 ± 8.06 degrees, P < 0.001), and the T1 slope (T1s) was significantly greater for the DCS group than for the control group (27.29 ± 7.84 degrees vs. 22.28 ± 6.43 degrees, P= 0.001). Except for SCA and T1s, no other parameters showed significant differences. The SCA on the computed tomography scan was significantly correlated with the values of the T1s (r=-0.890, P < 0.001), cervical lordosis (r=-0.437, P= 0.002), C2-C7 sagittal vertical axis (r=0.397, P= 0.004), and thoracic inlet angle (r=-0.565, P < 0.001). Multivariate logistic regression analysis and receiver operating characteristic curve analysis showed that both a lower SCA and a higher T1s could be risk factors for DCS, and an SCA of <79.1 degrees demonstrated significant diagnostic value for the detection of DCS. Patients in the DCS group had a lower SCA and a higher T1s. Both a lower SCA and a higher T1s could be risk factors for DCS, and an SCA of <79.1 degrees demonstrated significant diagnostic value for the detection of DCS.

Assessment of spino cranial angle of cervical spine sagittal balance system after multi-level anterior cervical discectomy and fusion

BackgroundTo analyze the impact of spino cranial angle (SCA) on alteration of cervical alignment after multi-level anterior cervical discectomy fusion (ACDF) and explore the relationship between SCA and health-related quality of life (HRQOL) scores.Material and methodsIn total, 49 patients following multi-level ACDF for multi-level cervical spondylotic myelopathy (MCSM) with more than 2 years follow-up period were enrolled. Radiographic data including SCA were measured. Receiver operating characteristics (ROC) curve analysis was applied to confirm the optimal cut-off values of SCA for predicting sagittal balance. Patients were divided into two groups on the basis of the cut-off value of preoperative SCA. Correlation coefficients were analyzed between SCA and HRQOL scores.ResultsOptimal cut-off values for predicting sagittal balance was SCA of 88.6°. Patients with higher SCA, no matter preoperatively, postoperatively and at follow-up, got lower T1-Slope (T1s), C2–C7 lordosis angle (CA) and higher △SCA (pre vs post: p = 0.036, pre vs F/U: p = 0.022). Simultaneously, pre-SCA, post-SCA, and F/U-SCA in the high SCA group were positively correlated with the pre-NDI, post-NDI, and F/U-NDI scores respectively (pre: p < 0.001, post: p = 0.015, F/U: p = 0.003). However, no correlation was performed in the low SCA group.ConclusionAn excessive SCA can be considered to cause poorer clinical outcomes at preoperative and better correction after surgery. The SCA could be used as a new reference value to determine sagittal balance parameters of the cervical spine and to assess the quality of life.

Comparison of Zero-profile Anchored Spacer Versus Plate-and-Cage After 1-Level ACDF With Complete Uncinate Process Resection: A 3-Year Assessment of Radiographic and Clinical Outcomes.

This is a retrospective study. The purpose of this study is to compare the zero-profile anchored spacer device (Zero-p) and traditional plate-and-cage implant (plate-and-cage) in anterior cervical discectomy and fusion (ACDF) with complete uncinate process resection (UPR) to treat 1-level cervical degenerative disk disease. We retrospectively surveyed the data from all patients who underwent single-level ACDF with complete UPR between 2009 and 2013. In total, 80 patients participated in 3 years of follow-up. Among them, Zero-p (38 patients) and plate-and-cage (42 patients) approaches were used in ACDF with complete UPR. Clinical outcomes and radiographic results were compared between 2 groups and they were followed for 39.1±2.2 months. Duration of operation, intraoperative blood loss, and length of hospitalization were significantly lower in the Zero-p group than the plate-and-cage group (P<0.001). The clinical outcomes of visual analog scale, neck disability index, and the Odom criteria were improved after operation in both groups. The fusion rates, C2-C7 lordosis, T1 slope, C2-C7 sagittal vertical axis, sellar turcica-C7 sagittal vertical axis, and spinocranial angle after single-level ACDF were not significantly different between the 2 groups. Subsidence occurred in 5 cases (13%) in the Zero-p group and 10 cases (37%) in the plate-and-cage group (P<0.05). The horizontal length of the Zero-p implant was longer than that of allograft bone. Fusion occurred in 37 cases (95%) of the Zero-p group and 40 cases (94%) in the plate-and-cage group. The Zero-p and plate-and-cage are effective when single-level ACDF with complete UPR was performed. Both groups showed good clinical outcomes, but Zero-p has more benefits than plate-and-cage such as lower duration of operation, intraoperative blood loss, length of hospitalization, and rate of subsidence compared with plate-and-cage. Surgeons should be aware of these results so that postoperative complications such as subsidence can be avoided.

A Novel Perspective for Analyzing Craniocervical Sagittal Balance and Horizontal Gaze

This study aimed to analyze craniocervical sagittal balance parameters in an asymptomatic population revealing the interaction of craniocervical compensation with the horizontal gaze and to identify a new parameter that can be evaluated more easily with the horizontal gaze. Lateral radiographs were taken of the 75 asymptomatic volunteers. Two independent observers measured the pelvic, spinal, and cranial parameters, spinocranial angle, and C2-7 sagittal vertical axis (C2-7SVA) distances. The correlations between these parameters and the differences in the created subgroups were analyzed. Correlations were found between the sacral slope and L1-L5 lordosis (r= 0.700), between L1-L5 lordosis and thoracic kyphosis (r= 0.363), between thoracic kyphosis and C2-7 lordosis (r= 0.425), and between C2-7 lordosis and C2 slope (C2S) (r=-0.735). In addition, this chain was extended to include the cranium, showing a strong correlation between the C2S and the cranial slope (CS) (r=-0.827). Strong correlations were observed between the CS and C2S (r=-0.827), C2-C7 lordosis (r= 0.583), C2-7 SVA (r=-0.437). The importance of O-C2 lordosis was significantly increased in the patient cohort with a prominent C2S (≥13) and became the main determinant of the CS (r= 0.667) together with the C2S (r=-0.800). The factors affecting horizontal gaze are C2S, C2-7 lordosis, O-C2 lordosis, and C2-7 SVA. C2S can be used as an indicator of the horizontal gaze in preoperative surgical planning and postoperative evaluation.

Influence of SCA on clinical outcomes and cervical alignment after laminoplasty in patients with multilevel cervical spondylotic myelopathy

BackgroundTo study the impact of changes in spino-cranial angle (SCA) on sagittal alignment and to investigate the relationship between SCA and Neck Disability Index (NDI) scores after laminoplasty (LP)Material and methodsIn total, 72 patients with multilevel cervical spondylotic myelopathy (MCSM) after laminoplasty (LP) were retrospectively enrolled. Based on the optimal cut-off values of preoperative SCA, patients were classified into low SCA and high SCA groups. Radiographic data were measured, including spino-cranial angle (SCA), T1-slope (T1s), C2–7 lordosis (CA), T1s minus CA (T1sCA), and C2–7 sagittal vertical axis (cSVA). JOA and NDI scores were both applied to assess postoperative and follow-up clinical efficacy. Pearson correlation coefficient and linear regression analysis were respectively calculated between radiographic data and between SCA and NDI.ResultsThe preoperative SCA was significantly correlated with T1s (r = − 0.795), CA (r = − 0.857), and cSVA (r = 0.915). A receiver operating characteristic (ROC) curve model predicted a threshold of SCA (value of 85.2°). At the follow-up period, patients with lower SCA had a higher T1s and CA and a lower cSVA, simultaneously accompanied by greater △T1s, △CA, and △cSVA. The linear regression model demonstrated that SCA in the higher group was positively correlated with NDI, and patients with higher SCA had worse NDI scores (pre: p < 0.001; post: p < 0.001; F/U: p = 0.003) and greater changes of NDI (post: p < 0.010; F/U: p = 0.002).ConclusionSCA may be a good predictor of evaluating sagittal balance and planning surgery. Changes in sagittal alignment in the low SCA group were affected more easily, and a higher SCA was associated with worse quality of life. Laminoplasty could be a good choice for patients with lower SCA.

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.

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.