A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment

Study Design: Retrospective analysis of consecutive case series. Objective: To introduce a novel method of stabilizing the cranium using bivector traction in posterior cervical fusions. Methods: A retrospective review of 50 consecutive patients undergoing instrumented posterior cervical arthrodesis was performed. All patients had at least 3 levels of subaxial fusion using the bivector traction apparatus. Patients’ demographic data was recorded for the following: pre- and postoperative cervical lordosis, pre- and postoperative cervical sagittal vertical alignment (cSVA), and intraoperative complications from pin placements. Results: A total of 50 patients were studied. There were 31 females and 19 males. The mean age at the time of surgery was 49 years (range 35-79). A mean 5.8 levels were fused. The most common levels fused were C2-T3 in 14 patients followed by C2-T2 in 7 patients. In no case did the surgeon or assistant have to scrub out to adjust the alignment. The mean pre- and postoperative cervical lordosis was −6.0° and −10°, respectively ( P = .04). The mean pre-and postoperative cSVA was 30.5 mm and 32 mm, respectively ( P = .6). There were no complications related to placement of the Gardner-Well tongs. Conclusion: The bivector traction is an easy, safe, and effective method of stabilizing the head and obtaining adequate cervical sagittal alignment.

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Cervical sagittal alignment in patients with dropped head syndrome

Journal of Orthopaedic Surgery ◽

10.1177/2309499021990112 ◽

2021 ◽

Vol 29 (1) ◽

pp. 230949902199011

Author(s):

Weiqing Qian ◽

Kenji Endo ◽

Takato Aihara ◽

Yasunobu Sawaji ◽

Hidekazu Suzuki ◽

...

Keyword(s):

Cervical Spondylosis ◽

Sagittal Alignment ◽

Vertical Axis ◽

Spinal Alignment ◽

Sagittal Vertical Axis ◽

Dropped Head Syndrome ◽

Sagittal Spinal Alignment ◽

Cervical Sagittal Alignment ◽

Lumbar Alignment ◽

The Relationship

Background: Dropped head syndrome (DHS) can be divided into two types, the positive sagittal vertical axis (SVA) type and the negative SVA type. However, the cervical sagittal alignment of DHS including global sagittal spinal alignment and the typical cervical alignment of the types of DHS is still unclear. The purpose of this study was to clarify the character of cervical sagittal alignment of DHS and analyze the relationship between cervical sagittal alignment and global sagittal spinal alignment. Methods: The subjects were 35 DHS patients (10 men, 25 women, mean 71.1 years old). They were divided into two groups: negative DHS (N-DHS group, SVA < 0 mm) and positive DHS group (P-DHS group, SVA ≥ 0 mm). As control, 28 age-matched cervical spondylosis patients (CS, 21 men, 7 women, mean 67.4 years old) were analyzed. The following parameters were measured on lateral global-spine standing radiographs: cervical SVA (C2-C7SVA), O-C2A (O-C2 angle), C2 slope (C2S), C2-7A (C2-7 angle), T1 slope (T1S) and C7SVA. Results: The results of measurements of each of the averaged sagittal alignment parameters were (CS, P-DHS, N-DHS): C2-7SVA(26.2 mm, 47.3 mm, 44.5 mm), O-C2 angle (35.0°, 37.1°, 39.3°), C2S (16.5°, 31.4°, 33.8°), C2-7A (9.3°, 9.9°, −16.6°), T1S (22.9°, 39.7°, 25.7°), C7SVA (35.3 mm, 51.0 mm, −43.1 mm). C2-C7SVA and C2S were significantly larger in both types of DHS compared to CS. Comparing P-DHS with N-DHS, C2-C7A and T1S were significantly smaller in N-DHS. Conclusions: O-C2A did not differ significantly among CS, P-DHS and N-DHS. In DHS patients, C2-7SVA and C2S were significantly larger than those of CS regardless of the type of DHS. The typical cervical sagittal alignment of DHS was different between P-DHS and N-DHS. In P-DHS, C2-7A and T1S were larger than those in N-DHS and the imbalance of thoraco-lumbar alignment should be noted.

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Improvement in cervical lordosis and sagittal alignment after vertebral body sliding osteotomy in patients with cervical spondylotic myelopathy and kyphosis

Journal of Neurosurgery Spine ◽

10.3171/2020.3.spine2089 ◽

2020 ◽

Vol 33 (3) ◽

pp. 307-315 ◽

Cited By ~ 1

Author(s):

Dong-Ho Lee ◽

Choon Sung Lee ◽

Chang Ju Hwang ◽

Jae Hwan Cho ◽

Jae-Woo Park ◽

...

Keyword(s):

Vertebral Body ◽

Cervical Spondylotic Myelopathy ◽

Sagittal Alignment ◽

Japanese Orthopaedic Association ◽

Vertical Axis ◽

Sacral Slope ◽

Cervical Lordosis ◽

Sagittal Vertical Axis ◽

Segmental Lordosis

OBJECTIVEVertebral body sliding osteotomy (VBSO) is a safe, novel technique for anterior decompression in patients with multilevel cervical spondylotic myelopathy. Another advantage of VBSO may be the restoration of cervical lordosis through multilevel anterior cervical discectomy and fusion (ACDF) above and below the osteotomy level. This study aimed to evaluate the improvement and maintenance of cervical lordosis and sagittal alignment after VBSO.METHODSA total of 65 patients were included; 34 patients had undergone VBSO, and 31 had undergone anterior cervical corpectomy and fusion (ACCF). Preoperative, postoperative, and final follow-up radiographs were used to evaluate the improvements in cervical lordosis and sagittal alignment after VBSO. C0–2 lordosis, C2–7 lordosis, segmental lordosis, C2–7 sagittal vertical axis (SVA), T1 slope, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and Japanese Orthopaedic Association scores were measured. Subgroup analysis was performed between 15 patients with 1-level VBSO and 19 patients with 2-level VBSO. Patients with 1-level VBSO were compared to patients who had undergone 1-level ACCF.RESULTSC0–2 lordosis (41.3° ± 7.1°), C2–7 lordosis (7.1° ± 12.8°), segmental lordosis (3.1° ± 9.2°), and C2–7 SVA (21.5 ± 11.7 mm) showed significant improvements at the final follow-up (39.3° ± 7.2°, 13° ± 9.9°, 15.2° ± 8.5°, and 18.4 ± 7.9 mm, respectively) after VBSO (p = 0.049, p < 0.001, p < 0.001, and p = 0.038, respectively). The postoperative segmental lordosis was significantly larger in 2-level VBSO (18.8° ± 11.6°) than 1-level VBSO (10.3° ± 5.5°, p = 0.014). The final segmental lordosis was larger in the 1-level VBSO (12.5° ± 6.2°) than the 1-level ACCF (7.2° ± 7.6°, p = 0.023). Segmental lordosis increased postoperatively (p < 0.001) and was maintained until the final follow-up (p = 0.062) after VBSO. However, the postoperatively improved segmental lordosis (p < 0.001) decreased at the final follow-up (p = 0.045) after ACCF.CONCLUSIONSNot only C2–7 lordosis and segmental lordosis, but also C0–2 lordosis and C2–7 SVA improved at the final follow-up after VBSO. VBSO improves segmental cervical lordosis markedly through multiple ACDFs above and below the VBSO level, and a preserved vertebral body may provide more structural support.

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Evaluation of Correlation between the Cross-sectional Area of Posterior Cervical Extensor Muscles and Cervical Sagittal Alignment in Patients with Hirayama Disease

10.21203/rs.3.rs-827562/v1 ◽

2021 ◽

Author(s):

Ye Tian ◽

Lin Xie ◽

Jianyuan Jang ◽

Hongli Wang

Keyword(s):

Cobb Angle ◽

Vertebral Body ◽

Sagittal Alignment ◽

Cross Sectional Area ◽

Sectional Area ◽

Spearman Correlation ◽

Cross Sectional ◽

Hirayama Disease ◽

Extensor Muscles ◽

Cervical Sagittal Alignment

Abstract Purpose: To assess correlation between the cross-sectional area (CSA) of posterior cervical extensor muscles (PCEMs) and the cervical sagittal alignment in Hirayama disease (HD) patients.Methods: We analyzed the MRI (Magnetic resonance imagine) T2WI and X-rays of 60 male HD patients who visited our hospital from June 2017 to February 2020. Their mean age was 18.95±1.67 years (range 16-22 years). MRI image is used to measure the CSA of cervical PCEMs. The ratio of muscle CSA to vertebral body areas (VBA) at the same level is defined as R-CSA. Cervical sagittal alignment includes C2-7 cobb angle, T1 slope, and C2-7 sagittal vertical axis (SVA). The geometric center of the C3-6 vertebral body was determined using the line connecting the C2 inferior endplate and the C7 upper endplate. When located behind the line, it is defined as a “Local kyphotic deformity” (LKD). The number of vertebral bodies involved in kyphotic deformity was determined by Local kyphosis angle (LKA) measured. Spearman correlation analysis (α=0.05) was used to determine the relationship between R-CSA and sagittal parameters. Results: Spearman correlation test revealed that R-CSA negatively correlated with T1S (S=0.34, p=0.01) and LKA (S=0.44, p=0.01) but did not correlated with C2-C7 cobb angle (S= 0.20, p=0.12) or C2-C7 SVA (S=-0.17, p=0.46). (p＜0.05)Conclusions: In Hirayama disease, the CSA of PCEMs is related to T1s and LKA and exercising the PCEMs should be given enough attention.

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Why the patients with Hirayama disease have abnormal cervical sagittal alignment? A radiological measurement analysis of posterior cervical extensors

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02905-5 ◽

2022 ◽

Vol 17 (1) ◽

Author(s):

Ye Tian ◽

Lin Xie ◽

Jianyuan Jiang ◽

Hongli Wang

Keyword(s):

Cobb Angle ◽

Sagittal Alignment ◽

Spearman Correlation ◽

Kyphosis Angle ◽

Hirayama Disease ◽

Cutoff Value ◽

T1 Slope ◽

Cervical Sagittal Alignment ◽

Local Kyphosis ◽

The Relationship

Abstract Purpose To explore the relationship between the strength of posterior cervical extensors (PCEs) and cervical sagittal alignment in Hirayama disease (HD) patients. Methods We analyzed the (magnetic resonance imaging) MRI T2WI and X-rays of 60 HD patients who visited Huashan Hospital from June 2017 to February 2020. Symptoms of these patients include adolescent onset, manifestation of unilateral upper limb muscle weakness and muscle atrophy of the forearm and hand. MRI images were used to measure (the cross-sectional area) CSA of cervical PCEs. The ratio of muscle CSA to vertebral body areas at the same level is defined as R-CSA. Cervical sagittal alignment includes the C2–7 Cobb angle, T1 slope and C2–7 sagittal vertical axis (SVA). The geometric center of the C3–6 vertebral body was determined using the line connecting the C2 inferior endplate and the C7 upper endplate. When located behind the line, it is defined as a “local kyphotic deformity.” The number of vertebral bodies involved in kyphotic deformity was determined by measuring the local kyphosis angle (LKA). Spearman correlation analysis (α = 0.05) was used to determine the relationship between R-CSA and sagittal parameters. ROC curves were used to analyze the sensitivity and specificity of relevant variables. Results Spearman correlation test revealed that R-CSA negatively correlated with T1S (S = 0.34, r = 0.34, p = 0.01) and LKA (S = 0.44, r = 0.5, p = 0.01), but did not correlate with the C2-C7 Cobb angle (S = 0.20, p = 0.12) or C2-C7 SVA (S = − 0.17, p = 0.46). (p < 0.05). ROC curve analysis showed that the areas under the curve (AUCs) of the T1 slope and LKA was 0.6696 and 0.7646, respectively. T1 slope, cutoff value: 17.2°; sensitivity: 0.5806; specificity: 0.7241; p < 0.05. LKA: cutoff value: − 14°; sensitivity: 1; specificity: 0.5333; p < 0.05. Conclusions In patients with Hirayama disease, the strength of posterior cervical extensors and cervical sagittal alignment are closely related. The local kyphosis angle can be used as a reference for the strength of posterior cervical extensors. These results indicate the weakness of PCEs, which may predispose the cervical spine of HD patients to a less stable situation. Therefore, patients with Hirayama disease should strengthen the exercise of the PCEs.

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Demonstration of central conduction time and neuroplastic changes after cervical lordosis rehabilitation in asymptomatic subjects: a randomized, placebo-controlled trial

Scientific Reports ◽

10.1038/s41598-021-94548-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ibrahim M. Moustafa ◽

Aliaa A. Diab ◽

Fatma Hegazy ◽

Deed E. Harrison

Keyword(s):

Sagittal Alignment ◽

Controlled Trial ◽

Placebo Treatment ◽

Controlled Study ◽

Control Group ◽

Conduction Time ◽

Cervical Lordosis ◽

Cervical Sagittal Alignment ◽

Experimental Group ◽

Head Translation

AbstractA randomized controlled study was conducted to evaluate the effect of rehabilitation of the cervical sagittal configuration on sensorimotor integration and central conduction time in an asymptomatic population. Eighty (32 female) participants with radiographic cervical hypolordosis and anterior head translation posture were randomly assigned to either a control or an experimental group. The experimental group received the Denneroll cervical traction while the control group received a placebo treatment. Interventions were applied 3 × per week for 10 weeks. Outcome measures included radiographic measured anterior head translation distance, cervical lordosis (posterior bodies of C2–C7), central somatosensory conduction time (latency) (N13–N20), and amplitudes of potentials for spinal N13, brainstem P14, parietal N20 and P27, and frontal N30. Outcomes were obtained at: baseline, after 10 weeks of intervention, and at 3 months follow up. After 10 weeks and 3-months, between-group analyses revealed statistically significant differences between the groups for the following measured variables: lordosis C2–C7, anterior head translation, amplitudes of spinal N13, brainstem P14, parietal N20 and P27, frontal N30 potentials (P < 0.001), and conduction time N13–N20 (P = 0.004). Significant correlation between the sagittal alignment and measured variables were found (P < 0.005). These findings indicate restoration of cervical sagittal alignment has a direct influence on the central conduction time in an asymptomatic population.

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An assessment of the most reliable method to estimate the sagittal alignment of the cervical spine: analysis of a prospective cohort of 138 cases

Journal of Neurosurgery Spine ◽

10.3171/2016.10.spine16632 ◽

2017 ◽

Vol 26 (5) ◽

pp. 572-576 ◽

Cited By ~ 6

Author(s):

Roland D. Donk ◽

Michael G. Fehlings ◽

Wim I. M. Verhagen ◽

Hisse Arnts ◽

Hans Groenewoud ◽

...

Keyword(s):

Cervical Spine ◽

Vertebral Body ◽

Sagittal Balance ◽

Interrater Reliability ◽

Sagittal Alignment ◽

Controlled Trial ◽

Cervical Alignment ◽

Cervical Sagittal Alignment ◽

Tangent Method ◽

The Mean

OBJECTIVEAlthough there is increasing recognition of the importance of cervical spinal sagittal balance, there is a lack of consensus as to the optimal method to accurately assess the cervical sagittal alignment. Cervical alignment is important for surgical decision making. Sagittal balance of the cervical spine is generally assessed using one of two methods; namely, measuring the angle between C-2 and C-7, and drawing a line between C-2 and C-7. Here, the best method to assess sagittal alignment of the cervical spine is investigated.METHODSData from 138 patients enrolled in a randomized controlled trial (Procon) were analyzed. Two investigators independently measured the angle between C-2 and C-7 by using Harrison's posterior tangent method, and also estimated the shape of the sagittal curve by using a modified Toyama method. The mean angles of each quantitative assessment of the sagittal alignment were calculated and the results were compared. The interrater reliability for both methods was estimated using Cronbach's alpha.RESULTSFor both methods the interrater reliability was high: for the posterior tangent method it was 0.907 and for the modified Toyama technique it was 0.984. For a lordotic cervical spine, defined by the modified Toyama method, the mean angle (defined by Harrison's posterior tangent method) was 23.4° ± 9.9° (range 0.4°–52.4°), for a kyphotic cervical spine it was −2.2° ± 9.2° (range −16.1° to 16.9°), and for a straight cervical spine it was 10.5° ± 8.2° (range −11° to 36°).CONCLUSIONSAn absolute measurement of the angle between C-2 and C-7 does not unequivocally define the sagittal cervical alignment. As can be seen from the minimum and maximum values, even a positive angle between C-2 and C-7 could be present in a kyphotic spine. For this purpose, the modified Toyama method (drawing a line from the posterior inferior part of the vertebral body of C-2 to the posterior upper part of the vertebral body of C-7 without any measurements) is a better tool for a global assessment of cervical sagittal alignment.Clinical trial registration no.: ISRCTN41681847 (https://www.isrctn.com)

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Effect of Cervical Sagittal Balance on Laminoplasty in Patients With Cervical Myelopathy

Global Spine Journal ◽

10.1177/2192568217694011 ◽

2017 ◽

Vol 7 (2) ◽

pp. 154-161 ◽

Cited By ~ 12

Author(s):

Minori Kato ◽

Takashi Namikawa ◽

Akira Matsumura ◽

Sadahiko Konishi ◽

Hiroaki Nakamura

Keyword(s):

Neck Pain ◽

Cervical Myelopathy ◽

Sagittal Balance ◽

Sagittal Alignment ◽

Clinical Status ◽

Cervical Sagittal Balance ◽

Cervical Sagittal Alignment ◽

Group A ◽

Group B ◽

The Relationship

Study Design: Retrospective clinical study. Objective: We evaluated the relationship between cervical sagittal alignment parameters and clinical status in patients with cervical myelopathy and analyzed the effect of cervical sagittal balance on cervical laminoplasty. Methods: Patients with cervical myelopathy (n = 110) who underwent laminoplasty were included in this study. The relationship between cervical sagittal alignment parameters and clinical status was evaluated. The changes in radiographic cervical sagittal parameters and clinical status 2 years after surgery were compared between patients with preoperative C2-7 SVA ≥35 mm (group A) and those with preoperative C2-7 SVA <35 mm (group B). Results: Preoperatively, C2-7 SVA had no correlation with defined health-related quality of life evaluation scores. At 2-year follow-up, the improvement in SF-36 physical component summary was significantly lower in group A than in group B. The postoperative change of C2-7 SVA did not significantly differ in 2 groups. Patients in group A maintained cervical regional balance after laminoplasty but experienced extensive postoperative neck pain. Conclusions: Our patients with a C2-7 SVA of ≥35 mm maintained cervical regional balance after laminoplasty and their improvement in myelopathy was equivalent to that in patients with a C2-7 SVA of <35 mm. However, the patents with a C2-7 SVA of ≥35 mm experienced severe postoperative neck pain. C2-7 SVA is a parameter worth considering because it can lead to poor QOL and axial neck pain after laminoplasty.

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The Influence of Natural Head Position on the Cervical Sagittal Alignment

Journal of Healthcare Engineering ◽

10.1155/2017/2941048 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7

Author(s):

Kuan Wang ◽

Zhen Deng ◽

Zhengyan Li ◽

Huihao Wang ◽

Hongsheng Zhan

Keyword(s):

Cervical Spine ◽

Sagittal Alignment ◽

Vertical Axis ◽

Head Position ◽

Biomechanical Analysis ◽

Sagittal Vertical Axis ◽

Cervical Sagittal Alignment ◽

Backward Shift ◽

The Relationship ◽

Curvature Type

Introduction. This study investigated the relationship between the parameters related to the natural head position and cervical segmental angles and alignment of patients with neck pain. Material and Methods. The lateral radiographs of the cervical spine were collected from 103 patients and were used to retrospectively analyze the correlation between the natural head position, cervical local sagittal angles, and alignment. Sagittal measurements were as follows: cervical curvature classification, slope of McGregor’s line (McGS), local sagittal angles (C0–C2 angle, C2–C5 angle, C5–C7 angle, and C2–C7 angle), T1 slope, center of gravity of the head to sagittal vertical axis (CG–C7 SVA), and local sagittal alignment (C0–C2 SVA and C2–C7 SVA). Results. McGS was significantly correlated to C0–C2 angle (r=0.57), C0–C2 SVA (r=−0.53), C2–C7 SVA (r=−0.28), and CG–C7 SVA (r=−0.47). CG–C7 SVA was also significantly correlated to curvature type (r=0.27), C5–C7 angle (r=−0.37), and C2–C7 angle (r=−0.39). Conclusions. A backward shift with an extended head position may accompany a relatively normal curvature of the cervical spine. The effect of posture control in relieving abnormal mechanical state of the cervical spine needs to be further confirmed by biomechanical analysis.

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