C2-7 Cobb Angle Research Articles

Long-term Radiographic Outcome of Occipitocervical Fixation: An Analysis of Fusion Rate and Spontaneous Subaxial Alignment Change at an Average 7-year Follow-up.

Retrospective case series. The aim of this study was to investigate the long-term radiographic outcome of patients who underwent occipitocervical fixation (OCF) using a modern screw/rod system. Few studies have reported fusion rates and radiographic alignment changes in unfused subaxial segments after OCF at a long-term follow-up. We retrospectively reviewed 22 patients who underwent OCF with a modern screw-based construct. The patients satisfied the minimum 2-year radiographic follow-up. Baseline demographics and the following pre- and postoperative sagittal alignment parameters were investigated. McGregor slope, O-C2 angle (OC2A), and C2-7 Cobb angle (CL). We grouped patients into those whose OC2A increased postoperatively (OC2A-increase group) and those whose OC2A decreased postoperatively (OC2A-decrease group). The postoperative sagittal alignment change was compared between the 2 groups at the final follow-up. The perioperative complications as well as fusion status based on computed tomography (CT) were investigated. The average follow-up period was 89.7 months. The lowest instrumented vertebra was at C2 (63.6%), C3 (18.1%), or C4 (18.1%). The fusion rate at the final follow-up was 77.2%. Postoperative dysphasia occurred in two patients (16.6%) in the OC2A-decrease group, whereas distal junctional kyphosis was observed in two patients (20.0%) in the OC2A-increase group. The OC2A-increase group demonstrated a mean 4.8° decrease in CL as a compensation for the 5.1° increase in OC2A. In contrast, the OC2A-decrease group showed a mean 9.2° increase in CL as a compensation for the 6.3° decrease in OC2A. The CT-confirmed fusion rate of OCF was 77.2% over an average 89.7-month follow-up. Compensatory sagittal alignment change can occur in the unfused subaxial segments in conjunction with the alignment change in the instrumented OC segments, whereas the horizontal gaze was maintained. Strong consideration for the intraoperative measurement of the OC2A should be given during OCF to minimize both early and long-term complications.Level of Evidence: 4.

Association between Changes in Sagittal X-ray Measurements and Neck Extensor Muscle Atrophy after Cervical Laminoplasty

BackgroundTo investigate the association between neck extensor muscles (NEM) atrophy and changes in the sagittal cervical X-ray measurements after cervical laminoplasty. Basic proceduresThis retrospective analysis was conducted on 64 patients who underwent cervical laminoplasty from March 2016 to March 2019. The preoperative and postoperative sagittal cervical X-ray images were measured, including the C2-C7 cobb angle, the C2-7 sagittal vertical axis (SVA), and the angle between the plane of the upper endplate of T1 vertebra and the horizontal plane (T1 slope). The preoperative and postoperative steatosis ratios of the NEM were measured using magnetic resonance images. Main findingsThere were significant differences between the preoperative and postoperative measurements of the C2-7 cobb angle, the C2-7 SVA, and the T1 slope (P<0.05). The preoperative and postoperative steatosis ratios of each intervertebral level of the NEM also differed significantly (P<0.05). The muscle atrophy ratio at C3/4 was positively correlated with the change in the C2-7 SVA (R=0.646, P<0.001) and negatively correlated with the change in the C2-7 cobb angle (R=-0.445, P<0.001). The muscle atrophy ratio at C7/T1 was positively correlated with the T1 slope (R=0.446, P<0.001). ConclusionsMuscle atrophy was more severe at the attachment points of the NEM (C3/4, C7T1). There was a significant association between the muscle atrophy ratio and the changes in sagittal cervical X-ray measurements.

Impact of Nonlordotic Sagittal Alignment on Short-term Outcomes of Cervical Disc Replacement

ObjectiveTo evaluate outcomes of cervical disc replacement (CDR) in patients with nonlordotic alignment. MethodsPatients who underwent CDR were retrospectively reviewed and divided into 3 cohorts: (1) neutral/lordotic segmental and C2–7 Cobb angle (L), (2) nonlordotic segmental Cobb angle, lordotic C2–7 Cobb angle (NL-S), and (3) nonlordotic segmental and C2–7 Cobb angle (NL-SC). Radiographic and patient-reported outcomes (PROMs) were compared. ResultsOne-hundred five patients were included (L: 37, NL-S: 30, NL-SC: 38). A significant gain in segmental lordosis was seen in all cohorts at < 6 months (L: -1.90° [p = 0.007]; NL-S: -5.16° [p < 0.0001]; NL-SC: -6.00° [p < 0.0001]) and ≥ 6 months (L: -2.07° [p = 0.031; NL-S: -6.04° [p < 0.0001]; NL-SC: -6.74° [p < 0.0001]), with greater lordosis generated in preoperatively nonlordotic cohorts (p < 0.0001). C2–7 lordosis improved in the preoperatively nonlordotic cohort (NL-SC: 8.04°) at follow-up of < 6 months (-4.15°, p=0.003) and ≥ 6 months (-6.40°, p=0.003), but not enough to create lordotic alignment (< 6 months: 3.89°; ≥ 6 months: 4.06°). All cohorts showed improvement in Neck Disability Index, visual analogue scale (VAS) neck, and VAS arm, without significant difference among groups in the amount of improvement (≥ 6-month PROMs follow-up=69%). ConclusionIn patients without major kyphotic deformity, CDR has the potential to generate and maintain lordosis and improve PROMs in the short-term, and can be an effective treatment option for patients with nonlordotic alignment.

21. The safety and efficacy of cervical laminectomy and fusion vs cervical laminoplasty surgery in degenerative cervical myelopathy: a prospective randomized trial

BACKGROUND CONTEXT There is a lack of evidence of whether degenerative cervical myelopathy (DCM) is best treated via cervical laminoplasty or cervical laminectomy with lateral mass fusion due to the lack of prospective randomized studies that are well designed. PURPOSE We conducted the largest prospective randomized trial to date to determine the comparative effectiveness and safety of both approaches. STUDY DESIGN/SETTING In this prospective, randomized trial, we randomly assigned patients who had symptoms or signs of DCM to undergo either cervical laminectomy and lateral mass fixation (CLF) or cervical laminoplasty (CLP). PATIENT SAMPLE A total of 39 patients (mean age, 55.7±5.5 years, 69.2% men) underwent prospective randomization. OUTCOME MEASURES The primary outcome measures were the change in the visual analog scale (VAS), Neck Disability Index (NDI), modified Japanese Orthopedic Association (mJOA) score, and Nurick's myelopathy grading one year after surgery. The secondary outcome measures were the intraoperative, postoperative complications, hospital stay, C2-7 Cobb's angle, and Odom's criteria. METHODS In this prospective, randomized trial, we randomly assigned patients who had symptoms or signs of DCM to undergo either cervical laminectomy and lateral mass fixation (CLF) or cervical laminoplasty (CLP). The primary outcome measures were the change in the visual analogue scale (VAS), neck disability index (NDI), modified Japanese Orthopedic Association (mJOA) score, and Nurick's myelopathy grading one year after surgery. The secondary outcome measures were the intraoperative, postoperative complications, hospital stay, C2-7 Cobb's angle, and Odom's criteria. The follow-up period was at least one year. RESULTS There was a significantly greater improvement in the NDI and VAS in the CLF group at one year (p CONCLUSIONS Among patients with multilevel DCM, the CLF approach was significantly better regarding the postoperative pain, NDI, and one-year Cobb's angle improvement, while the posterior approach was significantly better in terms of shorter hospital stay and operative time. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Could self-locking stand-alone cage reduce adjacent-level ossification development after aneterior cervical discectomy and fusion?

Numerous studies have shown that cervical arthrodesis is associated with the adjacent-segment pathology (ASP), such as adjacent-level ossification development (ALOD). However, it still remains largely unclear whether the self-locking stand-alone implant system can reduce the incidence of ALOD. In the present study, we prospectively recruited 120 patients with cervical degenerative disc disease (CDDD) who were treated by anterior cervical discectomy and fusion (ACDF). These patients were randomly and evenly divided into the ROI-C group and plate group. Clinical and radiologic follow-up was performed at 3, 6, 12, 24 and 36 months after surgery. Clinical evaluation included preoperative and postoperative assessments of Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI) score. The presence and severity of ALOD, as well as the C2-7 Cobb angle, were assessed on the lateral cervical films during follow-up. There were no significant differences in JOA and NDI scores at each time point during the follow-up period between the two groups. ALOD occurred in 8.8% of 58 patients and 6.7% of 104 levels in the cage group. Moreover, ALOD occurred in 20.1% of 57 patients and 17.8% of 101 levels in the plate group. The ALOD was more serious in the plate group compared with the cage group. The C2-7 Cobb angle was significantly improved compared with that before the operation and could be maintained during the follow-up in both groups. The self-locking stand-alone cage was efficacious for ACDF, and it could reduce the incidence of ALOD compared with anterior plate and cage.

Occipitocervical measurements: correlation and consistency between multi-positional magnetic resonance imaging and dynamic radiographs.

To evaluate the reliability and validity of the multi-positional magnetic resonance imaging in measuring occipitocervical parameters using the standard cervical dynamic radiographs as a reference. Patients were included if they underwent both dynamic radiograph and cervical multi-positional MRI within a 2-week interval from January 2013 to December 2016. Twelve occipitocervical parameters were measured on both image modalities in all positions (neutral, flexion and extension): Posterior Atlanto-Dental Interval, Anterior Atlanto-Dental Interval (AADI), Dens-to-McRae distance, Dens-to-McGregor distance, Occipito-atlantal Cobb angle (C01 angle), Occipito-axis Cobb angle (C02 Cobb angle), Atlas-axis Cobb angle (C12 angle), Redlund-Johnell, Modified Ranawat, Clivus canal angle, Occiput inclination, and Occiput cervical distance. Pearson correlation and linear regression analysis were used to evaluate the correlation of both modalities for each parameter. A p value of < 0.05 was considered statistically significant. Cervical images of 70 patients were measured and analyzed. There was a significant positive correlation between dynamic X-ray and multi-positional MRI for all parameters (p < 0.05) except AADI. Dens-to-McGregor distance and Redlund-Johnell parameter demonstrated a very strong correlation in the neutral position (r = 0.72, r = 0.79 respectively) and moderate to very strong correlation(r > 0.4) for Modified Ranawat, Clivus canal angle, C02 Cobb angle and C02 distance in all neck position. The intra-class correlation (ICC) of intra- and inter-observer showed good to excellent reliability, and ICCs were 0.67-0.98. Multi-positional MRI can be a reliable imaging option for diagnosis of occipitocervical instability or basilar invagination compared to standard dynamic radiographs.

Correlation between C7 slope and cervical lordosis in patients after expansive open-door laminoplasty

Purpose of the article: To investigate the correlation between C7 slope and cervical lordosis in patients after expansive open-door laminoplasty (EOLP).Material and methods: We retrospectively analyzed 57 patients who underwent EOLP between June 2013 and January 2017 in the Department of Spinal Surgery of our hospital. The operation time, intraoperative blood loss and follow-up time were recorded. The C7 slope, C2-7 sagittal vertical axis, and C2-7 Cobb angle were measured anteroposterior radiograph of the cervical spine preoperatively and postoperatively. All patients were divided into two groups according to the preoperative C7 slope (C7 slope ≤20° group and C7 slope >20° group).Results: The amount of intraoperative bleeding was 220.2 ± 180.9ml, and the operation time was 143.4 ± 51.2min. The average follow-up time was 24.9 ± 10.3months (range12–48 months). The C2-7 Cobb angle was 13.49 ± 10.46°at the final follow-up, which was significantly lower than that preoperatively (p = .026). But, The C7 slope and C2-7 sagittal vertical axis showed no significant difference between preoperatively and postoperatively. Preoperative and postoperative C7 slope and C2-7 Cobb angle were positively correlated to age and significant difference was observed. In the group of C7 slope >20°, significant difference was observed in term of the change of the C2-7 Cobb angle and C2-7SVA postoperatively (p = .009 and p= .020). However, there was no statistically significant difference detected in these two parameters in the group of C7 slope ≤20°.Conclusion: This study indicated that C7 slope could be used as an indicator of the change in the curvature of the cervical spine after EOLP. The loss of cervical curvature after surgery was prone to occur when C7 slope was greater than 20°, which should be noted in clinical practice.

Application of Zero-profile Spacer in the Treatment of Three-level Cervical Spondylotic Myelopathy: 5-year Follow-up Results.

A retrospective study. To assess the long-term results of zero-profile spacer for 3-level anterior cervical discectomy and fusion (ACDF). Although widely used, there are still controversies about the long-term results of zero-profile spacer, especially in multilevel cases. Cases received 3-level ACDF for cervical spondylotic myelopathy (CSM) using either zero-profile spacer (n = 27) (ZP Group), or plate and cages (n = 34) (PC Group), and with 5-year follow-up were reviewed. Neurological function and life quality were assessed by modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI), and Short-Form 36 (SF-36) score. Disc height, cervical lordosis, fusion rate, and surgical complications were observed. Neurological recovery and life quality improvement were similar in both groups. Disc height and cervical lordosis (C2-7 Cobb angle) were well restored after operations, but lost in both groups during follow-up. Loss of correction (LOC) in disc height was larger in ZP Group (11.38% vs 5.71%, P < 0.05) at 5-year follow-up. LOC of cervical lordosis in ZP group constantly grew from 11.28% to 48.13% during 5-year follow-up, significantly higher than that in the PC group (from 7.43% to 14.01%) (P < 0.05). The rate of postoperative dysphagia was no statistical difference between the two groups, and symptoms were all disappeared within 1 year. There were 10 levels of adjacent segment degeneration (1 in ZP Group, and 10 in PC Group, P = 0.02). Cage subsidence (11 of 81 levels, 13.58%) and screw migration (2 of 81 levels, 2.47%) were only observed in the ZP Group. The migrated screws in one case were surgically removed. Fusion was achieved in all cases. In long-term follow-up of 3-level ACDF for CSM, zero-profile spacer has the similar clinical results, but loss of correction of disc height and cervical alignment were significantly higher, compared with anterior plate and cages. 3.

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.

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

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

Sagittal Reconstruction and Clinical Outcome Using Traditional ACDF, Versus Stand-alone ACDF Versus TDR: A Systematic Review and Quantitative Analysis.

Systematic review. To determine the difference in postoperative sagittal alignment when single level cervical radiculopathy or myelopathy is treated with an anterior cervical discectomy and fusion (ACDF) using a structural graft and plate, a stand-alone ACDF, or a total disc arthroplasty (TDR). We also wanted to determine if postoperative sagittal alignment impacted clinical outcomes in this patient population. Although there are several accepted techniques for interbody reconstruction during single level anterior cervical surgery, little is known on the impact of any of them on segmental and regional sagittal alignment. A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines of the PubMed, Embase, and Cochrane databases. Only studies which contained pre and postoperative C2-7 Cobb angles as well as Neck Disability Index (NDI) scores following single level traditional ACDF with plate and cage, stand-alone ACDF, or TDR with at least 1 year follow up were included. There were 12 publications that fulfilled the inclusion criteria with a total of 658 patients. Cluster regression analysis showed no difference between treatment arms at each respective time-point or in the overall change in NDI from preoperative to postoperative (P = 0.88). Cluster regression analysis showed no difference between treatment arms at each respective time point or in the overall change in lordosis from pre-op to post-op (P = 0.93). This review provides evidence that while NDI scores improved across all devices, there was no significant difference in NDI improvement or C2-7 Cobb angle change between single level traditional ACDF, stand-alone ACDF, or TDR. Although TDR has not been considered a lordosis producing operation, our investigation shows it does not differ significantly in sagittal profile from other cervical fusion techniques. Moreover, we show that the NDI score improved, regardless of device implanted. 1.

208. Predictors of superior recovery kinetics in adult cervical deformity correction: an analysis using a novel area under the curve methodology

BACKGROUND CONTEXT Novel analyses of clinical outcomes following cervical deformity (CD) corrective surgery use an area-under-the-curve (AUC) method to assess health-related quality of life (HRQL) metrics throughout the surgical recovery process. It remains unclear how demographics, preop parameters, and surgical decisions are associated with superior recovery. PURPOSE Identify demographic, surgical and radiographic factors that predict superior recovery kinetics. STUDY DESIGN/SETTING Retrospective review of a prospective CD database. PATIENT SAMPLE A total of 98 CD patients. OUTCOME MEASURES Baseline (BL) to 1-year (1Y) HRQL Instruments: Neck Disability Index (NDI). METHODS CD database criteria:C2-7 Cobb angle>10°, coronal Cobb angle >10°, cSVA>4cm or TS-CL>10°, or CBVA>25°. Following univariate analyses, the AUC normalization method was utilized by dividing all reported BL and postoperative(3M, 1Y) outcome measures by the BL score. Normalized scores(y-axis) were plotted against follow-up time interval(x-axis). Total area was calculated for all follow-up, divided by cumulative follow-up length, determining overall, time-adjusted HRQL recovery (Integrated Health State[IHS]). IHS NDI scores were stratified by quartile, the uppermost 25% were categorized as having “superior” recovery kinetics (SRK) vs “normal” recovery kinetics (NRK). BL demographic, clinical and surgical information were used to predict SRK using generalized linear modeling. RESULTS A total of 98 patients included(62±10yrs, 28±6kg/m2, 65%F). Mean CCI: 0.95, 6% smokers, and 31% history of smoking. Surgical approach: combined(33%), posterior(49%), anterior(18%). Average posterior levels fused: 8.7, anterior levels fused: 3.6, EBL: 915.9ccs, op time: 495min. According to the Ames CD classification at BL: cSVA (53.2% minor deformity and 46.8% moderate), TS-CL (9.8% minor, 4.3% moderate, 85.9% marked), and horizontal gaze (27.4% minor, 46.6% moderate, 26% marked). Relative to BL NDI scores (mean: 47), normalized postop NDI scores showed decrease in disability at 3M(0.9±0.5, p=0.260) and a further decrease at 1Y (0.78±0.41, p CONCLUSIONS Superior recovery kinetics following cervical deformity surgery was predicted with high accuracy using a combination of baseline patient reported factors(VAS EQ5D, swallow sleep, and mJOA scores) and radiographic factors(TK, T10-T12, T12-S1, L1-S1). Patients and health care providers should be aware of these factors in order to improve surgical decision-making, in an effort to reduce postop neck disability. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Preoperative and Intraoperative Skull Traction Combined with Anterior-Only Cervical Operation in the Treatment of Severe Cervical Kyphosis (>50 Degrees)

To evaluate the clinical and radiographic outcomes of an anterior-only approach for the correction of severe cervical kyphotic deformities. We performed a retrospective study of 33 consecutive patients with severe cervical kyphosis treated with an anterior cervical operation and preoperative and intraoperative skull traction. Cobb angle, kyphosis index (KI), kyphosis level, C2-7 sagittal vertical axis (SVA), and T1 slope were measured. The preoperative and postoperative Japanese Orthopedic Association (JOA) scores, visual analog scale (VAS) score for neck pain, Neck Disability Index (NDI) scores, and cervical alignment were compared. The mean angle of the kyphosis was 83.2 ±20.4°. The mean Cobb angle of the operative region was 71.7 ± 18.5° preoperation, which was reduced to 10.6 ±5.7° postoperation (mean correction, 85.2%). The mean KI was 75.1 ± 18.2 preoperation, which was reduced to 14.4 ±9.1 postoperation (mean correction, 80.8%). The preoperative and postoperative mean C2-7 Cobb angle was 53.8 ± 16.5° and 14.7 ± 7.6°, respectively. The preoperative and postoperative mean C2-7 SVA was 3.9 ± 14.5 mm and 12.8 ± 7.3 mm, respectively. The preoperative and postoperative mean T1 slope was-9.4 ± 15.7° and 7.3 ± 13.1°, respectively. The average postoperative C2-7 Cobb angle, Cobb angle of the operative region, KI, C2-7 SVA, and T1 slope changed significantly compared with preoperative values (P < 0.05). The average postoperative JOA, VAS, and NDI scores improved significantly compared with preoperative scores (P < 0.05). Preoperative and intraoperative skull traction combined with anterior-only cervical operation may be a safe and effective technique for treating severe cervical kyphosis. If the postoperative correction is >80%, sufficient decompression could be achieved.

Radiological and Clinical Outcomes of Anterior Cervical Discectomy and Fusion in Older Patients: A Comparative Analysis of Young-Old Patients (Ages 65-74 Years) and Middle-Old Patients (Over 75 Years).

ObjectiveAnterior cervical discectomy and fusion (ACDF) is the most commonly performed procedure for degenerative cervical spondylosis. Because of its relatively low invasiveness and surgical procedure, old age is not regarded as an exclusion criterion for ACDF. However, very few studies have been conducted on the radiological and clinical outcomes of ACDF in older patients. The purpose of this study was to evaluate the radiological and clinical outcomes of ACDF in older patients. MethodsWe retrospectively analyzed 48 patients (> 65 years) who underwent ACDF from January 2011 to December 2015. We divided the patients into 2 groups: young-old age group (65–74 years) and middle-old age group (≥ 75 years). Cervical lateral radiographs taken in the neutral standing position were evaluated preoperatively (PRE), on postoperative day 7 (POST), and at the 1-year follow-up (F/U). The radiological parameters included cervical angle (CA: C2–7 Cobb angle), segmental angle, total intervertebral height, disc height, sagittal vertical axis (SVA), T1 slope (T1s), and range of cervical motion (extension CA minus flexion CA). Postoperative hospital days, comorbidities, complications, and clinical outcomes were also analyzed. ResultsWe analyzed data from 48 patients (group A: n = 30 patients, 46 segments, mean age, 68.60 ± 3.36 years; group B: n = 18 patients, 23 segments, mean age, 79.22 ± 2.63 years). The surgical levels were as follows: C3/4, 4; C4/5, 7; C5/6, 10; C6/7, 29; and C7/ T1, 6 levels, and there were no significant between-group differences in the distribution. There were no significant between-group differences in the fusion and subsidence rates (fusion rate: group A, 76.2%; group B, 71.4%; p = 0.732; subsidence rate: group A, 34.8%; group B, 26.1%; p = 0.587). There was no longitudinal trend in the repeated-measurements analysis of variance test of the 2 groups of the PRE, POST, and F/U data for each radiological parameter. According to the paired t-test, T1 slope (T1s), SVA, and CA did not differ preoperatively and postoperatively. There was no statistically significant difference in visual analogue scale scores (axial, arm), the Neck Disability Index, or Odom’s criteria between the 2 groups (p = 0.448, p = 0.357, and p = 0.913). ConclusionThere was no significant difference in radiological and clinical outcomes between young-old and middle-old patients. Middle-old age does not seem to be a limitation to ACDF, but larger-scale and longer-term studies are needed to confirm the findings of this study.

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

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

Comparison of Outcomes Between Anterior Cervical Decompression and Fusion and Posterior Laminoplasty in the Treatment of 4-Level Cervical Spondylotic Myelopathy

To compare the outcome of anterior cervical decompression and fusion (ACDF) and posterior laminoplasty (LAMP) for treating 4-level cervical spondylotic myelopathy (CSM). Data of 80 patients with 4-level CSM treated using ACDF and another 56 cases treated using LAMP were retrospectively analyzed. Radiologic outcomes evaluated by C2-7 Cobb angle and cervical range of motion (ROM) and functional outcomes evaluated by Japanese Orthopaedic Association (JOA) scale score and visual analog scale score for axial pain were compared between the 2 groups. JOA scale score in both groups improved significantly after operation (P < 0.05). There was no significant difference in the JOA scale score improvement rate between the 2 groups (P > 0.05). The C2-7 Cobb angle increased significantly in the ACDF group (P < 0.05) and decreased in the LAMP group (P > 0.05). There was a significant difference in C2-7 Cobb angle improvement between the 2 groups (P < 0.05). Cervical ROM decreased in both groups after operation (P < 0.05), but there was no significant difference in ROM loss ratio between the 2 groups (P > 0.05). Blood loss in the LAMP group was significantly more than in the ACDF group (P < 0.05); however, there was no significant difference in operation time between the 2 groups (P > 0.05). There was no significant difference in the complication rate between the 2 groups (P > 0.05). Both ACDF and LAMP were effective in the treatment of multilevel CSM. Compared with LAMP, ACDF is less invasive and may be more suitable for elderly patients with poor tolerance of surgery.

The effect of C2-3 disc angle on postoperative adverse events in cervical spondylotic myelopathy.

OBJECTIVEComplete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2-3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2-3 disc angle as an additional radiographic predictor of postoperative adverse events.METHODSA retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.RESULTSThe authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2-3 disc angle, C2-7 sagittal vertical axis, and C2-7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2-3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2-3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p < 0.0001).CONCLUSIONSIn the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2-3 disc angle and postoperative adverse events. They propose that C2-3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.

Postoperative Cervical Sagittal Realignment Improves Patient-Reported Outcomes in Chronic Atlantoaxial Anterior Dislocation.

Chronic atlantoaxial anterior dislocation (AAD) not only results in myelopathy, but dislocation-related kyphosis also results in cervical malalignment, which permanently affects neck function and patient-reported outcomes (PROs). To investigate the effect of kyphotic correction on realigning cervical spine and independent cervical alignment parameters, which may be correlated with an improvement of PROs. The study included 21 patients with chronic AAD-related kyphosis who underwent C1-2 reduction and correction surgery. Radiographic parameters were measured to assess cervical realignment preoperatively and postoperatively. Neck disability index (NDI), short form 12 physical component summary (SF-12 PCS), and Japanese Orthopaedic Association (JOA) scores were recorded to reveal changes in PROs. The independent parameters correlated with the improvements of PROs were analyzed. Of the radiographic parameters, the C1-2 Cobb angle, the C2-7 Cobb angle, thoracic inlet angle, cervical tilt, and T1 slope were significantly changed from -4.0° ± 16.2°, -29.2° ± 11.2°, 73.1° ± 13.3°, 30.4° ± 8.5°, and 29.1° ± 8.8° preoperatively to -13.5° ± 8.1° (P = .005), -18.0° ± 12.0° (P < .001), 67.1° ± 11.6° (P = .042), 23.1° ± 10.3° (P = .007), and 24.0° ± 7.0° (P = .011) at last follow-up, respectively. NDI, JOA, and SF-12 PCS scores were significantly improved postoperatively. The C1-2 Cobb angle was an independent parameter correlated with the improvements in SF-12 PCS, NDI, and JOA scores. Correction and reduction surgery can realign cervical spine in chronic AAD patients. The C1-2 Cobb angle was an independent parameter correlated with the improvements of PROs.

Evaluating Cervical Sagittal Alignment in Cervical Myelopathy: Are Sitting Cervical Radiographs and Standing Whole-Spine Radiographs Equally Useful?

Study Design:Retrospective review of medical charts and radiographic data.Objectives:We aimed to clarify the differences in cervical alignment findings between sitting cervical lateral radiographs and standing whole-spine lateral radiographs with clavicle positioning in cervical spondylotic myelopathy (CSM) patients.Methods:We retrospectively evaluated the radiographs of 50 consecutive patients who underwent cervical surgery for CSM in our hospital. Cervical sagittal alignment was evaluated based on the C0-2 angles and C2-7 Gore and Cobb angles. Head position was evaluated in terms of the center of gravity of the head to C7 (CGH-C7) angle and the McGregor angle (ie, the angle between the McGregor line and a horizontal line). The T1-slope was also evaluated.Results:The mean values of the CGH-C7 angle and T1-slope were significantly lower, while the mean value of the McGregor angle was significantly higher on whole-spine lateral radiographs with clavicle positioning than on sitting cervical lateral radiographs. The mean values of the C0-2 and C2-7 angles did not differ significantly between the 2 radiographic positioning approaches.Conclusions:Using whole-spine lateral radiographs with clavicle positioning may result in a significantly lower T1-slope and a posterior tilt of the head. In the absence of a compensatory change in cervical alignment, clavicle positioning may force patients to adopt an upward gazing position of the head. These compensatory mechanisms should be considered while evaluating cervical alignment on whole-spine lateral radiographs with clavicle positioning. Surgical planning should take into account the effect of posture on the radiographic appearance of cervical alignment.

A study of cervical sagittal parameters change after two modus of anterior cervicalsurgery in cervical myelopathy

Objective To analyze cervical sagittal parameters change after anterior cervical discectomy fusion (ACDF) and anterior cervical corpectomy fusion (ACCF) in cervical myelopathy. Methods 80 patients with cervical myelopathy who underwent anterior cervical surgery between March 2013 and October 2014 were analyzed in this study. 44 patients (24 males, 20 females) were operated by ACDF, with an average age of 59.5±4.26 years old and 36 patients (20 males, 16 females) were operated by ACCF, with an average age of 62.5±3.85 years old. Japanese Orthopaedic Association (JOA) scores, visual analogue scale(VAS) and neck disability index (NDI) were obtained in all patients preoperatively, 6 months after surgery and at the latest follow-up. Standing radiographs of cervical spine, CT (3D) and MR were obtained preoperatively, 6 months after surgery and at the latest follow-up. Cervical sagittal parameters were assessed with the following 3 parameters: C2-7 Cobb angle, C2-7 sagittal vertical axis(C2-7 SVA) and T1-Slope. Results All the patients were followed up from 18 to 26 months, with the average time of 22 months. The group of ACDF: JOA scores, VAS scores and NDI scores changed from 8.1±1.4, 5.8±1.2, 22.2±5.9 to 13.2±1.8, 1.5±1.4, 10.5±4.8. The group of ACCF: JOA scores, VAS scores and NDI scores changed from 7.3±1.6, 4.9±1.5, 24.2±4.3 to 13.9±1.1, 1.7±1.2, 11.3±4.2. There was no significant difference of JOA scores, VAS scores and NDI scoresbetween two group (t=1.544, 0.887, 1.666;P=0.134, 0.382, 0.107). The group of ACDF: C2-7 Cobb angle, C2-7 SVA and T1-Slope angle changed from 17.5°±4.7°, 20.3±9.3 mm, 35.2°±8.6° to 29.5°±5.2°, 11.2±8.6 mm, 28.7°±8.2°. The group of ACCF: C2-7 Cobb angle, C2-7 SVA and T1-Slope angle changed from 16.8°±5.1°, 19.5±8.6 mm, 34.6°±9.1° to 25.3°±4.2°, 15.7±9.2 mm, 30.3°±7.9°, with significant difference between the two group (t=2.75, 2.45, 2.34; P=0.039, 0.045, 0.043). The changes of T1-Slope angle in ACDF group were more significantly (P 25°) was decreased significantly. Compared with patients who had high T1-Slope preoperatively, the C2-7 Cobb in the patients with low T1-Slope was increased significantly. Conclusion Good curative effect could be achieved by ACDF and ACCF in cervical myelopathy. Both surgical methods can maintain the curvature of the cervical alignment and improve the sagittal balance parameters of the cervical alignment. Consideringthe cervical sagittal balance, the ACDF is more suitable for the patient with high T1-Slope angle preoperatively. Key words: Cervical spondylosis; Cervical vertebrae; Surgical procedures, operative