Changes In Cervical Alignment Research Articles

Cervical Alignment and Range of Motion Change after Anterior 3-Level Hybrid Surgery Compared with Cervical Laminoplasty: A Matched Cohort Study.

Cervical alignment and range of motion (ROM) changes after cervical spine surgery are related to cervical biomechanical and functions. Few studies compared these parameters between posterior laminoplasty and anterior 3-level hybrid surgery incorporating anterior cervical discectomy and fusion (ACDF) with cervical disc replacement (CDR). This study is aimed to detect the differences of cervical alignment and ROM changes of the two surgeries in a matched-cohort study. From January 2018 and May 2020, 51 patients who underwent 3-level hybrid surgery incorporating ACDF with ACDR were included. A 1:1 match of the patients who underwent cervical laminoplasty based on age, gender, duration of symptoms, body mass index, and cervical alignment type was utilized as control group. General data (operative time, blood loss, etc.), Japanese Orthopaedic Association (JOA) score, VAS (Visual Analog Score), NDI (The Neck Disability Index), cervical sagittal alignment, and cervical range of motion (ROM) were recorded and compared. Both groups gained significant improvement in JOA, VAS, NDI scores postoperatively (p < 0.05). Cervical alignment significantly increased in hybrid group and decreased in control group after surgeries (p < 0.001). ROM decrease was similar in two groups. For cervical lordosis, though cervical alignment angle in control group decreased, the final follow-up cervical alignment and cervical alignment changes were not significantly different between hybrid and control groups. For cervical non-lordosis, cervical alignment decreased in control group while increased in hybrid group. At final follow-up, cervical alignment and the changes between the two groups were significantly different. Both control group and hybrid group had similar ROM decrease after the surgery no matter whether there was cervical lordosis or non-lordosis. Hybrid surgery showed cervical alignments significantly improved and similar ROM preservation compared with control group at final follow-up both for 1-level and 2-level disc replacement subgroups. The hybrid surgery demonstrated advantages of preserving cervical alignment and gaining similar cervical ROM preservation compared with cervical laminoplasty, especially for cervical non-lordosis. Given the importance of restoring lordotic cervical alignment, hybrid surgery may be preferred over laminoplasty to treat multilevel cervical disc herniation.

The Effect of C2 Muscular Exposure Technique on Radiographic and Clinical Outcomes After C2-T2 Posterior Cervical Fusion.

Retrospective cohort analysis. To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications. In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF. All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale-Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups. A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P= 0.005) and more likely to have bone morphogenic protein (P< 0.001) and C2 pars screws (P= 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2-C3 segmental lordosis, C2-C3 listhesis, C0-C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2-C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups. Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF. Level III.

C1 Transposterior Arch Lateral Mass Screws Combined With C2 Pedicle Screw and Rod Fixation for Pediatric Atlantoaxial Subluxation: A Minimal 10-Year Follow-up Outcome Analysis.

Although the short-term outcomes of the 1-step reduction and fixation technique using C1 transposterior arch lateral mass screws combined with C2 pedicle screw and rod fixation system for the treatment of pediatric atlantoaxial subluxation (AAS) have been satisfactory, its long-term outcomes and impact on spinal development are not well studied. This study was intended to assess the long-term reliability of this technique for pediatric AAS. A retrospective case series study was conducted to analyze the minimum 10-year follow-up outcomes from 7 pediatric patients with AAS who underwent atlantoaxial fusion using the aforementioned technique. Quality of life and cervical range of motion were both measured thoroughly. In addition, vertical growth within the fusion construct (C1-2), overall cervical alignment, and subaxial cervical spine degeneration were evaluated radiographically. The mean age of the 7 patients was 8.14 ± 2.41 (6-12) years at the time of surgery. The mean follow-up period was 11.00 ± 1.15 (10-13) years. No patients presented identifiable intervertebral disk degeneration or segmental instability in the subaxial cervical spine except for 1 patient who showed mild intervertebral disk degeneration. Vertical growth did continue within the atlantoaxial complex after surgery (11.90% ± 2.37%); however, there was a decrease in the percentage of vertical growth compared with the corresponding normal populations of the same age and sex. Moreover, there was a significant decrease in the range of cervical extension and rotation motion, and the overall cervical alignment straightened at the latest follow-up. The 1-step reduction and fixation technique is a relatively reliable surgical technique for pediatric AAS, which does not adversely affect the postoperative quality of life or the subaxial cervical degeneration. Nevertheless, certain limitations, such as decreased cervical range of motion and changes in cervical alignment, should be concerned.

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

To investigate the pelvic incidence (PI)- and age-related cervical alignment changes of Chinese healthy population. Six hundred and twenty-five asymptomatic adult subjects, who underwent the standing whole spinal radiograph, were recruited in this work. The sagittal parameters were measured, including Occipito-C2 angle (O-C2), C2-7 angle (C2-7), cranial arch, caudal arch, T1-slope (T1S), C2-7 sagittal vertical axis (C2-7 SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), PI, and sagittal vertical axis (SVA). All subjects were stratified into 5 age groups, namely 40-59years, 60-64years, 65-69years, 70-74years, and 75years and above, with each age group further divided into 2 subgroups based on PI (deeming PI < 50° as low PI, and PI ≥ 50° as high PI). The correlations between PI or age, and other sagittal parameters were assessed. The age-related changes of sagittal parameters in each PI subgroup were also assessed, followed by one-way analysis of variance analysis for change comparison between age groups. The average cervical sagittal parameters were as below: 18.2 ± 6.8° for O-C2, 10.4 ± 10.2° for C2-7, 3.9 ± 7.5° for cranial arch, 6.5 ± 7.1° for caudal arch, 23.6 ± 7.3° for T1S, and 21.0 ± 9.7mm for C2-7 SVA. There was no obvious difference observed between PI and cervical sagittal parameters, excepting for caudal arch. While, C2-7, cranial arch, caudal arch, T1S, and C2-7 SVA increased remarkably with the age. Thereof, C2-7 exhibited great increases at the age of 60-64years and 70-74years, respectively, cranial arch increased notably at 60-64years of age, and caudal arch developed obviously at 70-74years of age, regardless of PI. This study showed the PI- and age-related cervical alignment changes of Chinese healthy population. Based on the classification in our study, high or low PI apparently did not correlate with the occurrence of cervical degenerative disease.

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

This work aimed to provide a comprehensive description of cervical alignment including cranial arch and caudal arch according to age, thus offering a reference database for cervical deformity treatment. Total 150 males and 475 females aged at 48-88 were enrolled from August 2021 to May 2022. Radiographic parameters were measured, including Occipito-C2 angle (O-C2), C2-7 angle (C2-7), cranial arch, caudal arch, T1-slope (T1s), and C2-7 sagittal vertical axis (C2-7 SVA). Pearson correlation coefficient was employed in analyzing associations among sagittal parameters and between age and each parameter. Five groups were set according to different age stages, namely group with age 40-59 (N = 77), group with age 60-64 (N = 189), group with age 65-69 (N = 214), group with age 70-74 (N = 97), and group with age exceeding 75 (N = 48). An analysis of variance (ANOVA) test was applied to compare multi-sets of cervical sagittal parameters (CSPs). Chi-square test or Fisher's exact test was used in assessing the relationships of various cervical alignment patterns with age groups. T1s exhibited the strongest correlation with C2-7 (r = 0.655) and caudal arch (r = 0.561), and moderately correlated with cranial arch (r = 0.355). The positive correlations between age and C2-7 angle (r = 0.189, P < 0.001), cranial arch (r = 0.150, P < 0.001), caudal arch (r = 0.112, P = 0.005), T1s (r = 0.250, P < 0.001), as well as C2-7 SVA (r = 0.090, P = 0.024) were observed. Moreover, two progressive growths of C2-7 were shown after 60-64 and 70-74years old, respectively. Thereof, cranial arch increased greatly after the age of 60-64, followed by a relative stability in the degeneration. The notable growth of caudal arch was observed after the age of 70-74, and the growth remained stable when exceeding the age of 75. The difference between cervical alignment patterns and age groups was obvious (Fisher's exact test P < 0.001). This work explored in detail the normal reference values of cervical sagittal alignment including cranial arch and caudal arch under different age groups. Age-related changes in cervical alignment depended on the increase in the cranial and caudal arches in different proportions with age.

Relationship between K-line distance and surgical outcome in cases of laminoplasty for cervical ossification of the posterior longitudinal ligament.

Although previous studies indicate that changes in cervical alignment after laminoplasty and dynamic factors influence surgical outcomes of cervical ossification of the posterior longitudinal ligament (OPLL), the relationship between the surgical outcomes, the distance between the kyphosis-line (K-line) and OPLL, and dynamic factors have not yet been quantitatively evaluated. The purpose of the present study was to analyze the relationship between ΔK-line distance and surgical outcomes in cases of laminoplasty for OPLL of the cervical spine. We retrospectively reviewed 46 consecutive patients (33 men and 13 women) with cervical OPLL who underwent laminoplasty. "K-line distance" was measured as the minimum interval between the K-line and OPLL on lateral radiographs. The following factors were analyzed: K-line distance in neutral, flexion, and extension neck positions, ΔK-line distance, preoperative C2-7 range of motion (ROM), preoperative segmental ROM, preoperative C2-7 lordotic angle, occupying ratio of the OPLL, disease duration, preoperative and postoperative Japanese Orthopaedic Association (JOA) score, and recovery rate. Patients were divided into flexion K-line (+) and flexion K-line (-) groups. We then analyzed the influence of the K-line distance on surgical outcomes and conducted multivariate analysis to analyze the factors affecting surgical outcomes. The JOA score recovery rate in the flexion K-line (-) group was significantly lower than that in the flexion K-line (+) group (P = .024). The ΔK-line distance was significantly negatively correlated with the JOA score recovery rate (r = -0.531, P < .001). Additionally, multivariate analysis showed that ΔK-line distance (OR = -2.143, P = .015) was negatively correlated with the JOA score recovery rate. The ΔK-line distance is considered useful for the quantitative evaluation of dynamic factors and static compression factors due to OPLL through the measurement of dynamic radiographic images.

P17. Biomechanical effects of changes in cervical alignment following single-level ACDF using 3D motion capture

<h3>BACKGROUND CONTEXT</h3> Alignment of the cervical spine likely has significant effects on the clinical longevity of the subaxial motion segments. The biomechanical effects of changes in alignment on the cervical spine remain to be understood. Single-level ACDF is a commonly performed procedure and cervical alignment may influence motion transfer to adjacent and noncontiguous subaxial motion segments. <h3>PURPOSE</h3> The purpose of this study is to better understand the role of alignment on unfused cervical motion segments, the present study was designed to evaluate the biomechanical effects on the subaxial cervical spine (C2 to T1) of 1) changes in T1 tilt 2) single-level ACDF and 3) combined effects of ACDF and changes in T1 tilt. <h3>STUDY DESIGN/SETTING</h3> Cadaveric study. <h3>PATIENT SAMPLE</h3> Six cadaveric cervical spines (C2-T1). <h3>OUTCOME MEASURES</h3> Biomechanical metrics. <h3>METHODS</h3> Six cadaveric cervical spines (C2-T1) were screened fluoroscopically and placed with retro-reflective markers. Computed tomography (CT) scans with sagittal/coronal reformats were performed and degeneration was graded. Specimens were tested to 30° flexion and 30° extension in the intact state and following single-level ACDF(C5-C6). Motions of each vertebral body were tracked using a 3D-motion capture system and input into an inverse kinematics model to correlate the 3D reconstruction and motion capture data. A customized testing apparatus was developed to alter the T1 slope in human cervical cadaveric spines to neutral, +15°, and -15°. Generalized estimating equation modeling was used to analyze the main effects as well as the interaction effects of fusion, while we also controlled for the clustered nature of the data. Parameter estimates of the model are reported as mean change in range of motion and standard error, with statistical significance defined as p-value = .05. SAS software was used for all statistical analyses. <h3>RESULTS</h3> In the intact specimen, increase in T1 tilt (0° to +15°) did not result in increased ROM at any motion segment (C2-3, C3-4, C4-C5, C5-6, C6-C7, C7-T1: p=NS). In the intact specimen, decrease in T1 tilt (0° to -15°) resulted in significantly increased ROM at C2-C3 (p < .0001), C3-C4 (p < .0001), C5-C6 (p < .01), C6-C7 (p <.005) and C7-T1 (p < .02), but not at C4-C5 (p=NS). The effects of ACDF on the unfused segments at various cervical alignments was: neutral T1 tilt, ACDF did not result in significantly increased ROM at any level (C2-3, C3-C4, C4-C5, C6-C7, C7-T1: p=NS). At increased T1 Tilt (+15°), motion was significantly increased at C2-C3 (p <.05); however, not at any other segment (p=NS). At decreased T1 tilt (-15°), there was a trend toward increased motion at C7-T1 (p=.06) and no significant increase in motion at any other level (p=NS). The GEE model did not show significant cumulative effects for the interaction of tilt and fusion on range of motion (p=NS). <h3>CONCLUSIONS</h3> Changes in cervical alignment have a biomechanical influence on the observed patterns of motion in both the intact state and following ACDF. In the unfused specimen, increased T1 tilt resulted in no significant hypermobility whereas decreased T1 tilt resulted in significantly increased hypermobility at five motion segments. Following ACDF, hypermobility was transferred to non-contiguous segments, cranially when T1 tilt was increased and trended caudally when T1 tilt was decreased. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

The Deterioration of Cervical Kyphosis During Neck Flexion after Laminoplasty Affects the Surgical Outcome of Cervical Spondylotic Myelopathy.

A retrospective single-center study. The present study investigated whether postoperative cervical alignment changes, in addition to preoperative patient backgrounds, imaging parameters, and disease severity, affect outcomes 1 year after laminoplasty. One hundred and three cervical spondylotic myelopathy (CSM) patients who underwent laminoplasty were enrolled. Preoperative and postoperative (1-year) Japanese Orthopedic Association (JOA) scores, cervical alignment, and balance on X-rays were assessed. Patients were classified into 2 groups for a univariate analysis according to the status of the recovery rate (RR) of the JOA score ≥50%. A multiple logistic regression analysis was performed to identify factors associated with good surgical outcomes a. The mean RR of the JOA score was 47.5% and the loss of cervical lordosis in the neutral position was 5.5°. The univariate analysis revealed slight differences in age, sex, and the duration of disease. Preoperative C2-7 angles were not significantly different. The C2-7 angle during flexion after surgery was significantly smaller in Group F. In the multiple logistic regression analysis, significant factors associated with the status of RR≥50% were a younger age (OR: .75, 95%CI: .59-.96), shorter duration of disease (OR: .94, 95%CI: .89-.99), and a lordotic C2-7 angle during neck flexion after surgery (OR: 1.47, 95%CI: 1.1-1.95). We retrospectively assessed the surgical outcomes of laminoplasty in 103 CSM cases. In addition to an older age and longer duration of disease, postoperative deteriorations in cervical kyphosis during neck flexion had a negative impact on outcomes.

Endplate abnormalities, Modic changes and their relationship to alignment parameters and surgical outcomes in the cervical spine.

Modic changes (MC) and endplate abnormalities (EA) have been shown to impact preoperative symptoms and outcomes following spinal surgery. However, little is known about how these phenotypes impact cervical alignment. This study aimed to evaluate the impact that these phenotypes have on preoperative, postoperative, and changes in cervical alignment in patients undergoing anterior cervical discectomy and fusion (ACDF). We performed a retrospective study of prospectively collected data of ACDF patients at a single institution. Preoperative magnetic resonance imagings (MRIs) were used to assess for the MC and EA. Patients were subdivided into four groups: MC-only, EA-only, the combined Modic-Endplate-Complex (MEC), and patients without either phenotype. Pre and postoperative MRIs were used to assess alignment parameters. Associations with imaging phenotypes and alignment parameters were assessed, and statistical significance was set at p < 0.5. A total of 512 patients were included, with 84 MC-only patients, 166 EA-only patients, and 71 patients with MEC. Preoperative MC (p = 0.031) and the MEC (p = 0.039) had significantly lower preoperative T1 slope compared to controls. Lower preoperative T1 slope was a risk factor for MC (p = 0.020) and MEC (p = 0.029) and presence of MC (Type II) and the MEC (Type III) was predictive of lower preoperative T1 slope. There were no differences in postoperative alignment measures or patient reported outcome measures. MC and endplate pathologies such as the MEC appear to be associated with worse cervical alignment at baseline relative to patients without these phenotypes. Poor alignment may be an adaptive response to these degenerative findings or may be a risk factor for their development.

Effect of cervical alignment change after anterior cervical fusion on radiological adjacent segment pathology

Adjacent segment pathology (ASP) is one of the primary complications affecting the long-term efficacy of anterior cervical fusion (ACF). At present, the cause and mechanism of adjacent segmental lesions are still controversial. We performed a retrospective analysis on 88 patients with cervical spondylotic myelopathy (CSM) who had been followed up for at least 1 year after ACF. The patients were divided into radiological adjacent segment pathology (RASP) and non-RASP groups according to the presence of postoperative RASP. On the lateral radiographs of the cervical spine of all patients taken before and after surgery at the short-term and final follow-ups, the following parameters were measured: C2-7 Cobb angle of the cervical vertebrae; Cobb angle of the operated segments; and the anterior and posterior height of the fused segments [i.e., the anterior fusion segment height (AFH) and the posterior fusion segment height (PFH)]. The intra- and inter-group differences of the patients before and after surgery were calculated, as well as correlation of ACF with the occurrence of RASP. There were 42 cases in the RASP group and 46 cases in the non-RASP group. In the RASP group, the C2-7 Cobb angle was significantly reduced in the short term after surgery (20.42±9.92° vs. 13.81±8.52°, P<0.01), while in non-RASP group the C2-7 Cobb angle was significantly increased in the short term after surgery (12.65±11.91° vs. 15.35±10.05°, P<0.05). The heights of both the anterior and posterior fused segments in the 2 groups were significantly higher after surgery, and they were significantly lower at the final follow-up than at the short-term follow-up. Post-operative AFH change was significantly correlated with C2-7 Cobb angle (r=0.274, P=0.010) and fused segment Cobb angle change (r=0.333, P=0.002). However, Cox regression analysis showed that only the postoperative C2-7 Cobb angle change was associated with RASP, with a hazard ratio of 0.336. Decreased cervical lordosis after ACF may be related to postoperative RASP. Maintaining good cervical curvature after surgery may reduce the incidence of RASP after ACF.

Single-level cervical disc arthroplasty in the spine with reversible kyphosis: A finite element study.

BackgroundOur previous studies found the single‐level cervical disc arthroplasty (CDA) might be a feasible treatment for the patients with reversible kyphosis (RK). Theoretically, the change of cervical alignment from lordosis to RK comes with the biomechanical alteration of prostheses and cervical spine. However, the biomechanical data of CDA in the spine with RK have not been reported. This study aimed at establishing finite element (FE) models to (1) explore the effects of RK on the biomechanics of artificial cervical disc; (2) investigate the biomechanical differences of single‐level anterior cervical discectomy and fusion (ACDF) and CDA in the cervical spine with RK.MethodsThe FE models of the cervical spine with lordosis and RK were constructed, then three single‐level surgical models were developed: (1) RK + ACDF; (2) RK + CDA; (3) lordosis + CDA. A 73.6‐N follower load combined with 1 N·m moment was applied at the C2 vertebra to produce cervical motion.ResultsAt the surgical level, “lordosis + CDA” had the greatest ROM (except for flexion) while “RK + ACDF” had the minimum ROM. However, at adjacent levels, the ROM of “RK + ACDF” increased by 4.05% to 38.04% in comparison to “RK + CDA.” “RK + ACDF” had the greatest prosthesis interface stress, while the maximum prosthesis interface stress of “RK + CDA” was at least 2.15 times higher than “lordosis + CDA.” Similarly, “RK + ACDF” had the greatest intradiscal pressure (IDP) at adjacent levels, while the IDP of “RK + CDA” was 1.6 to 6.7 times higher than “lordosis + CDA.” At the surgical level, “RK + CDA” had the greatest facet joint stress (except for extension), which was 1.9 to 11.2 times higher than “lordosis + CDA.” At the adjacent levels, “RK + CDA” had the greatest facet joint stress (except for extension), followed by “RK + ACDF” and “lordosis + CDA” in descending order.ConclusionsRK significantly changed the biomechanics of CDA, which is demonstrated by the decreased ROM and the significantly increased prosthesis interface stress, IDP, and facet joint stress in the “RK + CDA” model. Compared with ACDF, CDA overall exhibited a better biomechanical performance in the cervical spine with RK, with the increased ROM of surgical level and facet joint stress and the decreased ROM of adjacent levels, prosthesis interface stress, and IDP.

SMARTPHONE USAGE TIME, POSTURE OF THE CERVICAL REGION, AND ASSOCIATED FACTORS IN TEENAGE UNIVERSITY STUDENTS

Objective: This study aimed to assess the relationship between smartphone usage time and postural alignment in teenage university students and the associated factors. Methods: We carried out a cross-sectional study with 133 teenage university students (18-19 years old) between April and November 2018 in Fortaleza, Ceará, Brazil. Questionnaires were used to collect information on socioeconomic status, health conditions, smartphone usage time and level of physical activity. The alignment of the cervical region was assessed using photogrammetry in anatomical position and while texting on the smartphone. Horizontal alignment of the head (HAH), horizontal alignment of the acromion (HAA) and vertical alignment of the head (VAH) were measured. Bivariate and multivariate analyses were performed to check for factors associated with smartphone usage time (&gt;6 hours a day). Results: There were higher rates of girls (66.9%; n=89), people in the lower social class (71.4%; n=95), frequent drinkers (66.9%; n=89), people who complained of headache (83.5%; n=111) and people who used smartphones for more than 6 hours a day (72.9%; n=97). The multivariate analysis showed an association of smartphone usage time (&gt;6 hours a day) with cervical anteriorization, estimated by measuring the VAH (OR=1.053; p=0.007 – left side), female gender (OR=2.729; p=0.046), frequent drinking (OR=2.636; p=0.038) and complaint of headache (OR=5.617; p=0.002). Conclusions: There was a high percentage of adolescents who excessively used smartphones for more than 6 hours a day. Prolonged smartphone use was associated with female gender, alcohol consumption, headache and changes in cervical alignment.

107. Cervical alignment and distal junctional failure in posterior cervical fusion: a multicenter comparison of two surgical approaches

<h3>BACKGROUND CONTEXT</h3> Posterior cervical fusion (PCF) is successfully used to treat cervical spondylotic myelopathy, multilevel cervical stenosis, and cervical deformity. However, limited evidence exists regarding the appropriate level of proximal and distal extension of PCF constructs. Further investigation is required to understand the effects of construct endpoint on fusion rate, junctional failure, and sagittal deformity correction. <h3>PURPOSE</h3> To compare the surgical and radiographic outcomes of patients undergoing posterior cervical fusion (PCF) with constructs extending from C2-T2 to patients with constructs extending from C3-T1. <h3>STUDY DESIGN/SETTING</h3> This was a multicenter retrospective review of two prospective cohorts of patients undergoing PCF from C2-T2 or C3-T1 for subaxial cervical stenosis at two academic institutions from 2012 to 2020. <h3>PATIENT SAMPLE</h3> We identified 106 patients for inclusion in the C2-T2 cohort and 49 patients for inclusion in the C3-T1 cohort. <h3>OUTCOME MEASURES</h3> Pre- and postoperative cervical alignment parameters, distal screw loosening, distal junctional failure, and pseudarthrosis were measured. <h3>Methods</h3> Cervical alignment parameters were measured on both preoperative and postoperative radiographs performed greater than 6 months postoperatively. The cohorts were compared based on preoperative cervical alignment, postoperative cervical alignment, and change in cervical alignment. Postoperative radiographs were also assessed for signs of distal screw loosening, distal junctional failure, and pseudarthrosis. We utilized Student's t-test to compare all means between groups with p<0.05 deemed statistically significant. <h3>Results</h3> A total of 155 patients were included in the study (C2-T2: 106 patients, C3-T1: 49 patients). There were no significant differences in demographics or preoperative symptoms between cohorts. Fusion rates were significantly higher in the C2-T2 (93%) than the C3-T1 (80%, p=0.040) cohort. When comparing the C2-T2 to the C3-T1 cohort, the C3-T1 cohort had a significantly greater rate of proximal junctional failure (2% vs 10%, p=0.006), distal junctional failure (1% vs 20%, p<0.001) and distal screw loosening (4% vs 15%, p=0.02). Although ΔC2-7 Sagittal vertical axis increased significantly in both cohorts (C2-T2: 6.2°, p=0.04; C3-T1: 8.4°, p<0.001), correction did not significantly differ between groups (p=0.32). The C3-T1 cohort had a significantly greater increase in ΔC2 Slope (8.0° vs 3.1°, p=0.03) and ΔC0-C2 Cobb angle (6.4° vs 1.2°, p=0.04) <h3>Conclusions</h3> In patients undergoing PCF, a C2-T2 construct demonstrated lower rates of pseudarthrosis, DJF, PJF, and compensatory upper cervical hyperextension compared to a C3-T1 construct. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

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.

Clinical Effects of Preoperative K-Line Tilt on Patient Outcomes After Laminoplasty for Cervical Ossification of the Posterior Longitudinal Ligament

We sought to clarify the effects of the preoperative K-line tilt on cervical sagittal balance and patient outcomes after laminoplasty for cervical ossification of the posterior longitudinal ligament (OPLL). A retrospective analysis of 45 patients with OPLL treated by laminoplasty from January 2013 to December 2018 was performed. The radiological parameters included the K-line tilt, C2-C7 sagittal vertical axis, C2-C7 lordosis, T1 slope, and T1 slope minus C2-C7 lordosis. The patient quality of life outcomes were assessed using the neck disability index, Japanese Orthopaedic Association disability scale, and visual analog scale. The patients were classified into 2 groups according to the median preoperative K-line tilt angle (14.1°): the high K-line tilt group (n= 23) and the low K-line tilt group (n= 22). The postoperative cervical alignment changes and patient outcomes were compared and analyzed. The clinical outcomes demonstrated overall improvement at the final follow-up. The C2-C7 lordosis had significantly decreased from 13.5° ± 9.5° preoperatively to 10.2° ± 9.7°. The C2-C7 lordosis was less in the high K-line tilt group than that in the low K-line tilt group. In addition, the high K-line tilt group revealed significantly greater kyphotic changes and a greater loss of cervical lordosis compared with the low K-line tilt group. Finally, the quality of life outcomes and postoperative visual analog scale scores were higher in the high K-line tilt group. The results of the present study have shown that the parameter K-line tilt is an ideal radiological parameter for predicting the outcomes and determining the need for laminoplasty for cervical ossification of the OPLL. Patients with a higher K-line tilt preoperatively experienced more kyphotic alignment changes and neck pain after laminoplasty.

The Effect of Combined Treatment of Chiropractic and Shoulder Flexibility Exercises on the Balance Ability of the Deformed Cervical Alignment Subjects

OBJECTIVES The purpose of this study is to analyze the effect of changes in cervical alignment on balance ability, to correct cervical alignment, and to present effective interventional variables that can improve balance ability.METHODS Group 1 (Deformed cervical alignment group, n = 16) and Group 2 (Normal cervical alignment group, n = 16). The subjects measured their balance ability before and after treatment with chiropractic and shoulder flexibility exercises. Balance ability was measured by static balance and dynamic balance. For Group 1, chiropractic was treated once a week for 15 minutes, and shoulder flexibility exercise was treated three times a week for one hour. The pre- and post-measurement results of Group 1 were compared with Group 2, and differences among groups and groups were analyzed. The test method was tested with the Independent t-test and Paired t-test.RESULTS Group 1 showed a significant reduction (p&lt;0.04) in the distance between the 7th cervical spine and gravity line, showing an improvement in cervical alignment. In the static equilibrium, the significant difference that was measured beforehand disappeared and the sum of deflection decreased. The dynamic balance did not disappear significantly but the balance ability improved as the sum of deflection decreased.CONCLUSIONS The cervical alignment deformation affects the balance ability. A combination of cervical alignment correction and exercise to increase the flexibility of the shoulder and neck muscles were performed. As a result, it was a factor in improving the static balance and dynamic balance ability of the left and right sides of the cervical spine.

Analysis of Cervical Spine Alignment Change after Modified Kurokawa Cervical Laminoplasty in the Patients with Cervical Myelopathy and Straight Cervical Spine.

Laminoplasty is widely used to decompress the spinal cord in patients with multilevel cervical lesions. Straight cervical alignment may not be a good candidate for laminoplasty because of postoperation progression of kyphosis and loss of cervical spine range of motion (ROM). However, clinical outcomes of laminoplasty did not show a strong and consistent effect based on cervical sagittal alignment. Moreover, the kyphosis progression and ROM change after operation for the patients with preoperative strange cervical alignment are still unclear. This study is to evaluate the change of cervical alignment and ROM in patients with straight cervical alignment after modified Kurokawa cervical laminoplasty. Thirty patients with multiple-level cervical spondylosis (CSM) and straight cervical alignment were included. All patients underwent laminoplasty with the reconstruction of the spinous process-ligament-muscular complex (SPLMC). The modified JOA score was analyzed for clinical assessment. The change of cervical alignment, ROM, T1 slope, and intervertebral disc space Cobb angle were analyzed for radiological assessment. The average JOA score at preoperative and 2 years follow-up were 7.8 ± 1.4 and 13.6 ± 2.1, respectively. The recovery ratio was 63%. At the 2 years follow-up, there were 18 patients who acquired lordotic cervical alignment. 10 patients remained as straight cervical curve, and 2 patients' cervical alignment developed mild kyphosis. 28 out of 30 patients showed improvement of cervical alignment. The cervical alignment was improved from 1.29 ± 10.04° preoperative to 9.58 ± 8.65° postoperative. However, the ROM decreased from 36.8 ± 18.92 preoperative to 25.08 ± 12.10° postoperative. A positive correlation was found between the C2/4 angle change and cervical alignment change, T1 slope and cervical alignment, cervical alignment, and neutral position flexion reserved ROM. A negative correlation was found between the C1/2 angle change and cervical alignment change. Laminoplasty with a reconstruction of SPLMC followed by appropriate postoperative muscle exercises may be an encouraging way to maintain or improve physiological alignment and prevent postoperation kyphosis deformity for the CSM patients with straight cervical alignment at 2 years follow-up.

Correlation study between postoperative Dysphagia and change in cervical alignment after anterior cervical spine surgery

Background and Aim: Understanding the correlation between the development of Dysphagia and change in the cervical alignment after cervical spine surgery in patients. Methods: From 2017 to 2020, 198 patients were treated with anterior cervical decompression and plate fixation where 12 months examination and study follow-ups are undertaken on 172 patients. Along with, the other 154 patients underwent anterior cervical disc replacement where 12 months extensive follow-ups were commenced on 98 patients. The questionnaire was distributed among 270 patients under 12 months follow-ups to investigate the onset and time of appearance of dysphagia, symptoms, relief, treatment plan and other health issues associated, if any. After getting the detailed feedback, all the patients were divided into the dysphagia group and the control group, to determine the excessive cervical lordosis change and other risk factors were associated with the dysphagia symptom or not. Results: The results showed that 12.8% of patients have postoperative dysphagia in anterior cervical discectomy in fusion group and 5.1% of patients have in cervical disc replacement group. According to the regression equation, the excessive change of C2-C7 angle significantly increases the incidence rate of postoperative dysphagia. It was also observed that, the incidence rate of postoperative dysphagia was significantly greater in patients whose C2-C7 angle change more than 5 degree compare to the patients has less than 5 degree C2-C7 angle. The assessed parameters like Sex, age, BMI, operation time, blood loss, surgery approach, revision ratio, the number of surgical segments, the highest surgical segment, and C3 segment doesn’t affect the occurrence of dysphagia. Conclusions: Development of Dysphagia symptoms are highly prevalent comorbidities after cervical spine surgery in the patients. The change in the Cervical lordosis importantly influencing promoting the occurrence of dysphagia after anterior cervical spine surgery.

Risk Factors and Radiologic Changes in Subsidence after Single-Level Anterior Cervical Corpectomy: A Minimum Follow-Up of 2 Years.

ObjectiveAnterior cervical corpectomy using a titanium mesh cage may result in delayed nonunion and thus a change in cervical alignment, and patients may require revision surgery. We investigated the radiologic and clinical outcomes of cervical corpectomy and the risk factors for subsidence.MethodsWe studied 74 patients who underwent single-level anterior cervical corpectomy for cervical spondylotic myelopathy with or without ossification of the posterior longitudinal ligament between 2007 and 2014. Graft subsidence was considered present when there was a reduction in the anterior and posterior heights by an average of 4 mm or more 2 years after the operation. We measured cervical parameters before surgery, immediately after surgery, and 6, 12, and 24 months after surgery. The clinical outcomes were the neck and arm visual analog scale scores and reoperation rate.ResultsIn the subsidence group, these values gradually decreased over the 24 months. The radiologic parameters did not differ between the 2 groups for 24 months after the onset of subsidence. There were no differences in clinical outcome or reoperation rate. In the analysis of the risk factors, subsidence occurred with a large T1 slope and a large change in the C27 Cobb angle (p=0.020 and p=0.026, respectively).ConclusionSubsidence gradually occurred after single-level anterior cervical corpectomy for up to 24 months. However, the presence of subsidence did not affect the radiologic and clinical outcomes. When the T1 slope was large and the C27 Cobb angle change was severe, more subsidence occurred.

A Prospective Cohort Study of Dysphagia After Subaxial Cervical Spine Surgery.

Prospective observational cohort study. To prospectively examine dysphagia after subaxial cervical spine surgery. Although dysphagia after anterior cervical spine surgery is common and well-studied, it has rarely been examined in posterior subaxial cervical spine surgery. This study analyzed 191 consecutive patients (132 male, 59 female; mean age, 64.9 yrs) who underwent subaxial cervical spine surgery for degenerative disease and completed 1 year of follow-up. Anterior decompression with fusion (ADF) was performed in 87 patients, posterior decompression with fusion (PDF) in 21, and laminoplasty (LAMP) in 83. Dysphagia was evaluated by a self-administered questionnaire using the Bazaz dysphagia scale before, 6 months, and 1 year after surgery. Diagnosis, levels and number of operative segments, C2-7 lordotic angle (CL), O-C2 angle (OC2A), C2-7 range of motion (ROM), Japanese Orthopedic Association for cervical myelopathy (C-JOA) score, and neck pain visual analog scale (VAS) were examined. Thirty-two patients (16.8%) reported dysphagia before surgery. New dysphagia after surgery, defined as more than or equal to 1 grade worsening of the Bazaz score after surgery compared with the preoperative status, was observed in 38 patients (19.9%) at 6 months and 32 patients (16.8%) at 1 year. The incidence of new dysphagia at 1 year was 25.3% in the ADF group, 23.8% in the PDF group, and 6.0% in the LAMP group. Fusion surgery (ACDF or PDF) and increased CL after surgery were found as risk factors at 1 year in multivariate analysis; receiver operating characteristic analysis determined a postsurgical change in CL cutoff of 5°. Fusion surgery and increased CL after surgery were risk factors for development of dysphagia after subaxial cervical spine surgery. Cervical alignment change due to anterior and posterior fusion surgery can cause postoperative dysphagia.Level of Evidence: 3.