Global sagittal spinal alignment at cervical flexion in patients with dropped head syndrome

Purpose: Dropped head syndrome (DHS) is characterized by the passively correctable chin-on-chest deformity. The characteristic feature is emphasized in the cervical flexion position. The purpose of this study was to analyze the influence of cervical flexion on sagittal spinal alignment in patients with DHS. Methods: The study included 15 DHS subjects and 55 cervical spondylosis (CS) subjects as the control group. The following parameters were analyzed: cervical sagittal vertical axis (C-SVA), occipitoaxial angle (O–C2A), C2 slope (C2S), C2–C7 angle (C2–C7A), T1 slope (T1S), sagittal vertical axis, T1–T4 angle (T1–T4A), T5–T8 angle (T5–T8A), T9–T12 angle, lumbar lordosis, sacral slope, and pelvic tilt, in cervical flexion and neutral positions. Results: The values of C-SVA, O–C2A, C2S, and T1S were significantly different between CS and DHS at cervical neutral and flexion positions. C2–C7A showed significant difference in cervical neutral position, but the difference disappeared in flexion position. T1–T4A did not present a significant difference, but T5–T8A showed a difference in neutral and flexion positions. Conclusions: Malalignment of DHS extended not only to cervical spine but also to cranio-cervical junction and thoracic spine, except T1–T4. It is known that global sagittal spinal alignment is correlated with adjacent parameters, although in DHS the reciprocal change was lost from cranio-cervical junction to the middle part of thoracic spine at cervical flexion.

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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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Analysis of the Effect of Backpack Design with Reduced Load Moment Arm on Spinal Alignment

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16224351 ◽

2019 ◽

Vol 16 (22) ◽

pp. 4351

Author(s):

Kyung-hun Kim ◽

Jihyeon Ann ◽

Sang-hun Jang

Keyword(s):

Lumbar Lordosis ◽

Pelvic Incidence ◽

Vertical Axis ◽

Center Of Gravity ◽

The Body ◽

Moment Arm ◽

Spinal Alignment ◽

Sagittal Vertical Axis ◽

Sagittal Spinal Alignment ◽

Significant Difference

In this study, we designed a backpack that can reduce the moment arm of backpack load by placing the center of gravity of the backpack close to the axis of the spine. In order to investigate the effect of sagittal spinal alignment compared with the general backpack, we conducted the study using radiological images. The participants in this study were 18 adults (8 males and 10 females). The subjects participated in the experiment without carrying the backpack, wearing the normal backpack, and wearing a backpack designed to reduce the load moment arm by placing the center of gravity close to the body. Spinal alignment parameters were measured and analyzed using 3D radiography measurement software based on radiographic images taken under three conditions. The overall angle of lumbar lordosis, upper arc, lower arc, difference between pelvic incidence and lumbar lordosis, lower cervical lordosis, and sagittal vertical axis were measured. In the case of wearing the backpack rather than without the backpack, there was a significant difference in the overall angle of lumbar lordosis, lower arc, lower cervical spine angle, difference between pelvic incidence and lumbar lordosis, and sagittal vertical axis. In the case of wearing the backpack with reduced moment arm, the overall angle and lower arc of lumbar lordosis were significantly increased compared to those with the normal backpack. The difference between pelvic incidence and lumbar lordosis was significantly decreased. The results showed that a normal backpack caused imbalance of sagittal spinal alignment, and the backpack reducing the load moment arm by placing the backpack’s center of gravity close to the vertebral joint played a positive role in reducing the change of lumbar alignment compared with the normal backpack.

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The utility of supine radiographs in the assessment of thoracic flexibility and risk of proximal junctional kyphosis

Journal of Neurosurgery Spine ◽

10.3171/2020.11.spine201565 ◽

2021 ◽

pp. 1-7

Author(s):

Francis Lovecchio ◽

Renaud Lafage ◽

Jonathan Charles Elysee ◽

Alex Huang ◽

Bryan Ang ◽

...

Keyword(s):

Thoracic Spine ◽

Lumbar Lordosis ◽

Pelvic Tilt ◽

Pelvic Incidence ◽

Vertical Axis ◽

Control Analysis ◽

Proximal Junctional Kyphosis ◽

Sagittal Vertical Axis ◽

Significant Difference ◽

Junctional Kyphosis

OBJECTIVE Supine radiographs have successfully been used for preoperative planning of lumbar deformity corrections. However, they have not been used to assess thoracic flexibility, which has recently garnered attention as a potential contributor to proximal junctional kyphosis (PJK). The purpose of this study was to compare supine to standing radiographs to assess thoracic flexibility and to determine whether thoracic flexibility is associated with PJK. METHODS A retrospective study was conducted of a single-institution database of patients with adult spinal deformity (ASD). Sagittal alignment parameters were compared between standing and supine and between pre- and postoperative radiographs. Thoracic flexibility was determined as the change between preoperative standing thoracic kyphosis (TK) and preoperative supine TK, and these changes were measured over the overall thoracic spine and the fused portion of the thoracic spine (i.e., TK fused). A case-control analysis was performed to compare thoracic flexibility between patients with PJK and those without (no PJK). The cohort was also stratified into three groups based on thoracic flexibility: kyphotic change (increased TK), lordotic change (decreased TK), and no change. The PJK rate was compared between the cohorts. RESULTS A total of 101 patients (mean 63 years old, 82.2% female, mean BMI 27.4 kg/m2) were included. Preoperative Scoliosis Research Society–Schwab ASD classification showed moderate preoperative deformity (pelvic tilt 27.7% [score ++]; pelvic incidence–lumbar lordosis mismatch 44.6% [score ++]; sagittal vertical axis 42.6% [score ++]). Postoperatively, the average offset from age-adjusted alignment goals demonstrated slight overcorrection in the study sample (−8.5° ± 15.6° pelvic incidence–lumbar lordosis mismatch, −29.2 ± 53.1 mm sagittal vertical axis, −5.4 ± 10.8 pelvic tilt, and −7.6 ± 11.7 T1 pelvic angle). TK decreased between standing and supine radiographs and increased postoperatively (TK fused: −25.3° vs −19.6° vs −29.9°; all p < 0.001). The overall rate of radiographic PJK was 23.8%. Comparisons between PJK and no PJK demonstrated that offsets from age-adjusted alignment goals were similar (p > 0.05 for all). There was a significant difference in the PJK rate when stratified by thoracic flexibility cohorts (kyphotic: 0.0% vs no change: 18.4% vs lordotic: 35.0%; p = 0.049). Logistic regression revealed thoracic flexibility (p = 0.045) as the only independent correlate of PJK. CONCLUSIONS Half of patients with ASD experienced significant changes in TK during supine positioning, a quality that may influence surgical strategy. Increased thoracic flexibility is associated with PJK, possibly secondary to fusing the patient’s spine in a flattened position intraoperatively.

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Global sagittal spinal alignment in patients with degenerative low-grade lumbar spondylolisthesis

Journal of Orthopaedic Surgery ◽

10.1177/2309499019885190 ◽

2019 ◽

Vol 27 (3) ◽

pp. 230949901988519

Author(s):

Hiroto Kobayashi ◽

Kenji Endo ◽

Yasunobu Sawaji ◽

Yuji Matsuoka ◽

Hirosuke Nishimura ◽

...

Keyword(s):

Sacral Slope ◽

Low Grade ◽

Spinal Alignment ◽

Sagittal Spinal Alignment ◽

Significant Difference ◽

Degenerative Lumbar Spondylolisthesis ◽

Lumbar Spondylolisthesis ◽

Type 3

Purpose: Global sagittal spinal alignment undergoes changes on the basis of sagittal malalignment (trunk inclined forward) in natural degenerative progression. We hypothesized that this change would associate with the disease state of the degenerative lumbar spondylolisthesis (DS). This study aimed to evaluate the global sagittal spinal alignment of low-grade DS by classifying in accordance with sagittal vertical axis (SVA). Methods: The DS group was classified into three types according to the adult spinal deformity classification: type 1, SVA < 40 mm; type 2, 40 mm ≤ SVA < 95 mm; and type 3, 95 mm ≤ SVA. Age and sagittal spinal parameters (thoracic kyphosis, lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI)) were compared among three types. Results: There were statistically significant differences in age, LL, PI, and PT among the three types. In comparison between two types, there was a statistically significant difference between type 1 and type 2 and between type 1 and type 3, but not between type 2 and type 3 in these parameters. PI tended to increase as the type increases. Furthermore, there was significant difference between types 1 and 3. Conclusion: We evaluated the features of the DS types classified by sagittal alignment. Large PI is one of the risk factors for SVA deterioration of DS. PI may be involved in the onset and progression of DS.

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Increasing pelvic incidence is associated with more global sagittal imbalance in ankylosing spondylitis with thoracolumbar kyphosis

10.21203/rs.2.16543/v1 ◽

2019 ◽

Author(s):

Diyu Song ◽

Guoquan Zheng ◽

Tianhao Wang ◽

Dengbin Qi ◽

Yan Wang

Keyword(s):

Ankylosing Spondylitis ◽

Pelvic Incidence ◽

Vertical Axis ◽

Control Group ◽

Sacral Slope ◽

Sagittal Imbalance ◽

Thoracolumbar Kyphosis ◽

Spinopelvic Parameters ◽

Sagittal Vertical Axis ◽

The Relationship

Abstract Background: Ankylosing spondylitis (AS) patients with kyphosis have an abnormal spinopelvic alignment and pelvic morphology. Most of them focus on the relationship of pelvic tilt (PT) or sacral slope (SS) and deformity, and relatively few studies have addressed the relationship between pelvic incidence (PI) and kyphosis in AS patients. The purpose of this study is to analyze the correlation between pelvic incidence (PI) and the spinopelvic parameters describing local deformity or global sagittal balance in AS patients with thoracolumbar kyphosis. Methods: A total of 94 patients with AS (91 males and 3 females) and 30 controls were reviewed. Sagittal spinopelvic parameters, including PI, PT, SS, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis(LL), sagittal vertical axis(SVA), T1 pelvic angle(TPA), spinosacral angle(SSA) and spinopelvic angle(SPA) were measured. Statistical analysis was performed to identify the correlation of PI with other parameters. Results: Compared with the control group, the AS patients had significantly higher PI(47.4˚ vs. 43.2˚, P<0.001). PI in AS patients was found to be significantly positively correlated with TPA(r=0.533, R 2 =0.284, P<0.001), and negatively correlated with SPA(r=-0.504, R 2 =0.254, P<0.001). However, no correlations were found between PI and SVA, SSA, TK, TLK or LL in AS patients. Conclusion: The value of PI in AS patients with kyphosis was significantly higher than that of controls. Correlation analysis revealed that increasing PI was significantly correlated with more global sagittal imbalance, not with the local deformity in AS patients with thoracolumbar kyphosis.

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Novel Method for Evaluation of Sagittal Spinal Alignment Using Cluster Analysis of Slope of Each Vertebra.

10.21203/rs.3.rs-1111502/v1 ◽

2021 ◽

Author(s):

Yoshitaka Matsubayashi ◽

Yasushi Oshima ◽

Yuki Taniguchi ◽

Toru Doi ◽

So Kato ◽

...

Keyword(s):

Cluster Analysis ◽

Sagittal Alignment ◽

Thoracolumbar Junction ◽

Sacral Slope ◽

Spinal Alignment ◽

Sagittal Spinal Alignment ◽

Significant Difference ◽

Novel Method ◽

And Cluster Analysis ◽

Whole Spine

Abstract Background: The parameters of sagittal spinal alignment proposed to date measure only the specific sectional angle or the specific sectional distance of the entire spine. To evaluate the alignment of the entire spine without segmentation, we sought to measure and analyze the slope of each vertebral body from skull to pelvis. The purpose of this study was to confirm the effectiveness of this novel analytic method for the evaluation of spinal alignment that considers the slope of each spinal vertebra using graph and cluster analysis.Methods: Every spinal slope from McGregor’s slope to the sacral slope of 88 patients who underwent standing whole spine radiography was measured. Subsequently, we conducted cluster analysis of each spinal slope to understand the characteristics of sagittal alignment.Results: Cluster analysis of whole spinal slopes did not provide useful results in this study because the number of cases per cluster was small due to the large number of parameters. Therefore, we focused the cluster analysis on only the cervical spine slopes. Then, we categorized cervical alignment into four groups (named Normal, Mismatch, Straight, and Sigmoid) based on the results of the cluster analysis. Patients in the Normal and Mismatch groups were older and had lower lumbar apex (L4), apparent lordo-kyphosis around the thoracolumbar junction, and high thoracic kyphosis (TK). Patients in the straight and sigmoid groups were younger, had a higher lumbar apex (L3), flat thoracolumbar junction, and low TK. There was no significant difference between the four groups with respect to pelvic incidence (PI) or pelvic tilt (PT).Conclusion: We proposed a novel method for visually understanding sagittal alignment. Using this analysis method, differences and similarities of sagittal alignment between each group can be easily identified. More detailed analysis of the whole spine may be possible by increasing the number of cases.

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Small sagittal vertical axis accompanied with lumbar hyperlordosis as a risk factor for developing postoperative cervical kyphosis after expansive open-door laminoplasty

Journal of Neurosurgery Spine ◽

10.3171/2017.12.spine17557 ◽

2018 ◽

Vol 29 (2) ◽

pp. 176-181 ◽

Cited By ~ 3

Author(s):

Yuji Matsuoka ◽

Hidekazu Suzuki ◽

Kenji Endo ◽

Yasunobu Sawaji ◽

Kazuma Murata ◽

...

Keyword(s):

Vertical Axis ◽

Sagittal Imbalance ◽

Open Door ◽

Spinal Alignment ◽

Cervical Kyphosis ◽

Sagittal Vertical Axis ◽

Sagittal Spinal Alignment ◽

Lumbar Hyperlordosis ◽

The Difference ◽

Whole Spine

OBJECTIVEPreoperative positive cervical sagittal imbalance and global sagittal imbalance are risk factors for postoperative cervical kyphosis after expansive open-door cervical laminoplasty (ELAP). The purpose of this study was to investigate the relationship between the incidence of postoperative cervical kyphosis after ELAP and the preoperative global sagittal spinal alignment in patients with cervical spondylotic myelopathy (CSM) without spinal sagittal imbalance.METHODSAmong 84 consecutive patients who underwent ELAP for CSM at the authors’ hospital, 43 patients without preoperative cervical kyphosis (C2–7 angle ≥ 0°) and spinal sagittal imbalance (C2–7 sagittal vertical axis [SVA] ≤ 80 mm and C-7 SVA ≤ 95 mm) were included in the study. The global spinal sagittal parameters were measured on lateral whole-spine standing radiographs preoperatively and at 1 year postoperatively. The difference in preoperative global sagittal spinal alignment between the postoperative cervical lordosis group and the cervical kyphosis group was analyzed.RESULTSThe incidence of postoperative cervical kyphosis after ELAP was 25.6% (11 of 43 cases). Thirty-two patients (16 men and 16 women; mean age 67.7 ± 12.0 years) had lordosis, and 11 (7 men and 4 women; mean age 67.2 ± 9.6 years) had kyphosis. The preoperative C-7 SVA and pelvic incidence minus lumbar lordosis (PI−LL) in the kyphosis group were significantly smaller than those in the lordosis group (p < 0.05). The smaller C-7 SVA accompanied by a small PI−LL, the “truncal negative offset,” led to postoperative cervical kyphosis due to posterior structural weakening by ELAP.CONCLUSIONSIn patients with CSM without preoperative cervical and global spinal sagittal imbalance, a small SVA accompanied by lumbar hyperlordosis is the characteristic alignment leading to postoperative cervical kyphosis after ELAP.

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Can posterior stand-alone expandable cages safely restore lumbar lordosis? A minimum 5-year follow-up study

10.21203/rs.3.rs-27368/v3 ◽

2020 ◽

Author(s):

Seung-Kook Kim ◽

Ogeil Mubarak Elbashier ◽

Su-chan Lee ◽

Woo-jin Choi

Keyword(s):

Sagittal Balance ◽

Lumbar Lordosis ◽

Vertical Axis ◽

Control Group ◽

Sacral Slope ◽

Sagittal Vertical Axis ◽

Expandable Cage ◽

Cage Group

Abstract Background: Lumbar lordosis (LL) can be restored, and screw-related complications may be avoided with the stand-alone expandable cage method. However, the long-term spinopelvic changes and safety remain unknown. We aimed to elucidate the long-term radiologic outcomes and safety of this technique. Methods: Data from patients who underwent multi-level stand-alone expandable cage fusion and 80 patients who underwent screw-assisted fusion between February 2007 and December 2012, with at least 5 years of follow-up, were retrospectively analyzed. Segmental angle and translation, short and whole LL, pelvic incidence, pelvic tilt, sacral slope (SS), sagittal vertical axis, thoracic kyphosis, and presence of subsidence, pseudoarthrosis, retropulsion, cage breakage, proximal junctional kyphosis (PJK), and screw malposition were assessed. The relationship between local, lumbar, and spinopelvic effects was investigated. The implant failure rate was considered a measure of procedure effectiveness and safety. Results: In total, 69 cases were included in the stand-alone expandable cage group and 150 cases in the control group. The stand-alone group showed shorter operative time (58.48±11.10 versus 81.43±13.75, P=.00028), lower rate of PJK (10.1% versus 22.5%, P=.03), and restoration of local angle (4.66±3.76 versus 2.03±1.16, P=.000079) than the control group. However, sagittal balance (0.01±2.57 versus 0.50 ±2.10, P=.07) was not restored, and weakness showed higher rate of subsidence (16.31% versus 4.85 %, P=.0018), pseudoarthrosis (9.92% versus 2.42%, P=.02), cage, and retropulsion (3.55% versus 0, P=.01) than the control group.Conclusions: Stand-alone expandable cage fusion can restore local lordosis; however, global sagittal balance was not restored. Furthermore, implant safety has not yet been proven.

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Mode of onset of dropped head syndrome and efficacy of conservative treatment

Journal of Orthopaedic Surgery ◽

10.1177/2309499020938882 ◽

2020 ◽

Vol 28 (2) ◽

pp. 230949902093888

Author(s):

Takuya Kusakabe ◽

Kenji Endo ◽

Yasunobu Sawaji ◽

Hidekazu Suzuki ◽

Hirosuke Nishimura ◽

...

Keyword(s):

Conservative Treatment ◽

Recovery Rate ◽

Vertical Axis ◽

Acute Onset ◽

Sacral Slope ◽

Cervical Trauma ◽

Sagittal Vertical Axis ◽

Dropped Head Syndrome ◽

History Of ◽

Onset Group

Purpose: The initial treatment of dropped head syndrome (DHS) is basically nonsurgical, but the mode of onset of DHS and efficacy of conservative treatment have not been fully clarified. Methods: The subjects were 38 DHS patients without neuromuscular disease (11 men and 27 women, average age 74.5 years). Cervical collar, physical therapy, and temporary medication for cervical pain were provided for all DHS patients. The following parameters were measured on lateral global spine standing radiographs: sagittal vertical axis (SVA), cervical sagittal vertical axis, C2–C7 angle, first thoracic slope, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence. According to the mode of onset of DHS, the subjects were classified into acute-onset group (<3 months) and chronic-onset group (≥3 months). Results: Acute- and chronic-onset DHS were observed in 20 and 18 patients, respectively. A history of cervical trauma was involved in nine and two cases of acute- and chronic-onset DHS, respectively. Acute-onset DHS included more balanced-SVA (B-SVA: −30 mm <SVA ≤40 mm) than chronic-onset DHS. In conservative cases, the recovery rate was better in acute-onset DHS with B-SVA. In acute-onset DHS treated conservatively, the recovery rate was significantly poor in cervical trauma cases. Conclusions: Acute-onset DHS includes more balanced SVA and a history of cervical trauma, while acute-onset DHS without a history of cervical trauma has better prognosis by conservative treatment. Surgical indications for DHS should be carefully determined, and sufficient conservative treatment is essential.

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Impact of spinopelvic alignment on decision making in deformity surgery in adults

Journal of Neurosurgery Spine ◽

10.3171/2012.2.spine11320 ◽

2012 ◽

Vol 16 (6) ◽

pp. 547-564 ◽

Cited By ~ 161

Author(s):

Christopher P. Ames ◽

Justin S. Smith ◽

Justin K. Scheer ◽

Shay Bess ◽

S. Samuel Bederman ◽

...

Keyword(s):

Surgical Planning ◽

Vertical Axis ◽

Spinal Alignment ◽

Spinopelvic Parameters ◽

Sagittal Vertical Axis ◽

Radiographic Findings ◽

Spinopelvic Alignment ◽

Sagittal Spinal Alignment ◽

Cause Of Pain ◽

Proper Analysis

Sagittal spinal misalignment (SSM) is an established cause of pain and disability. Treating physicians must be familiar with the radiographic findings consistent with SSM. Additionally, the restoration or maintenance of physiological sagittal spinal alignment after reconstructive spinal procedures is imperative to achieve good clinical outcomes. The C-7 plumb line (sagittal vertical axis) has traditionally been used to evaluate sagittal spinal alignment; however, recent data indicate that the measurement of spinopelvic parameters provides a more comprehensive assessment of sagittal spinal alignment. In this review the authors describe the proper analysis of spinopelvic alignment for surgical planning. Online videos supplement the text to better illustrate the key concepts.

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