Global Spinal Alignment in Cervical Kyphotic Deformity: The Importance of Head Position and Thoracolumbar Alignment in the Compensatory Mechanism

Neurosurgery ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. 686-694 ◽  
Author(s):  
Jun Mizutani ◽  
Kushagra Verma ◽  
Kenji Endo ◽  
Ken Ishii ◽  
Kuniyoshi Abumi ◽  
...  

Abstract BACKGROUND Previous studies have evaluated cervical kyphosis (C-kypho) using cervical curvature or chin-brow vertical angle, but the relationship between C-kypho and global spinal alignment is currently unknown. OBJECTIVE To elucidate global spinal alignment and compensatory mechanisms in primary symptomatic C-kypho using full-spine radiography. METHODS In this retrospective multicenter study, symptomatic primary C-kypho patients (Cerv group; n = 103) and adult thoracolumbar deformity patients (TL group; n = 119) were compared. We subanalyzed Cerv subgroups according to sagittal vertical axis (SVA) values of C7 (SVAC7 positive or negative [C7P or C7N]). Various Cobb angles (°) and SVAs (mm) were evaluated. RESULTS SVAC7 values were –20.2 and 63.6 mm in the Cerv group and TL group, respectively (P < .0001). Various statistically significant compensatory curvatures were observed in the Cerv group, namely larger lumbar lordosis (LL) and thoracic kyphosis. The C7N group had significantly lower SVACOG (center of gravity of the head) and SVAC7 (32.9 and –49.5 mm) values than the C7P group (115.9 and 45.1 mm). Sagittal curvatures were also different in T4-12, T10-L2, LL4-S, and LL. The value of pelvic incidence (PI)-LL was different (C7N vs C7P; –2.2° vs 9.9°; P < .0003). Compensatory sagittal curvatures were associated with potential for shifting of SVAC7 posteriorly to adjust head position. PI-LL affected these compensatory mechanisms. CONCLUSION Compensation in symptomatic primary C-kypho was via posterior shifting of SVAC7, small T1 slope, and large LL. However, even in C-kypho patients, lumbar degeneration might affect global spinal alignment. Thus, global spinal alignment with cervical kyphosis is characterized as head balanced or trunk balanced.


2021 ◽  
Vol 29 (1) ◽  
pp. 230949902199011
Author(s):  
Weiqing Qian ◽  
Kenji Endo ◽  
Takato Aihara ◽  
Yasunobu Sawaji ◽  
Hidekazu Suzuki ◽  
...  

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.



2018 ◽  
Vol 29 (2) ◽  
pp. 176-181 ◽  
Author(s):  
Yuji Matsuoka ◽  
Hidekazu Suzuki ◽  
Kenji Endo ◽  
Yasunobu Sawaji ◽  
Kazuma Murata ◽  
...  

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.



2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Kuan Wang ◽  
Zhen Deng ◽  
Zhengyan Li ◽  
Huihao Wang ◽  
Hongsheng Zhan

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.



2019 ◽  
Author(s):  
Diyu Song ◽  
Guoquan Zheng ◽  
Tianhao Wang ◽  
Dengbin Qi ◽  
Yan Wang

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.



2020 ◽  
Vol 28 (3) ◽  
pp. 230949902094826 ◽  
Author(s):  
Takamitsu Konishi ◽  
Kenji Endo ◽  
Takato Aihara ◽  
Hidekazu Suzuki ◽  
Yuji Matsuoka ◽  
...  

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.



2020 ◽  
Vol 33 (2) ◽  
pp. 211-218
Author(s):  
Qing-shuang Zhou ◽  
Xu Sun ◽  
Xi Chen ◽  
Liang Xu ◽  
Bang-ping Qian ◽  
...  

OBJECTIVEThe aim of this study was to investigate sagittal alignment and compensatory mechanisms in patients with monosegmental spondylolysis (mono_lysis) and multisegmental spondylolysis (multi_lysis).METHODSA total of 453 adult patients treated for symptomatic low-grade spondylolytic spondylolisthesis were retrospectively studied at a single center. Patients were divided into 2 subgroups, the mono_lysis group and the multi_lysis group, based on the number of spondylolysis segments. A total of 158 asymptomatic healthy volunteers were enrolled in this study as the control group. Radiographic parameters measured on standing sagittal radiographs and the ratios of L4–S1 segmental lordosis (SL) to lumbar lordosis (L4–S1 SL/LL) and pelvic tilt to pelvic incidence (PT/PI) were compared between all experimental groups.RESULTSThere were 51 patients (11.3%) with a diagnosis of multi_lysis in the spondylolysis group. When compared with the control group, the spondylolysis group exhibited larger PI (p < 0.001), PT (p < 0.001), LL (p < 0.001), and L4–S1 SL (p = 0.025) and a smaller L4–S1 SL/LL ratio (p < 0.001). When analyzing the specific spondylolysis subgroups, there were no significant differences in PI, but the multi_lysis group had a higher L5 incidence (p = 0.004), PT (p = 0.018), and PT/PI ratio (p = 0.039). The multi_lysis group also had a smaller L4–S1 SL/LL ratio (p = 0.012) and greater sagittal vertical axis (p < 0.001).CONCLUSIONSA high-PI spinopelvic pattern was involved in the development of spondylolytic spondylolisthesis, and a larger L5 incidence might be associated with the occurrence of consecutive multi_lysis. Unlike patients with mono_lysis, individuals with multi_lysis were characterized by an anterior trunk, insufficiency of L4–S1 SL, and pelvic retroversion.



2019 ◽  
Vol 31 (5) ◽  
pp. 697-702 ◽  
Author(s):  
Nitin Agarwal ◽  
Federico Angriman ◽  
Ezequiel Goldschmidt ◽  
James Zhou ◽  
Adam S. Kanter ◽  
...  

OBJECTIVEObesity, a condition that is increasing in prevalence in the United States, has previously been associated with poorer outcomes following deformity surgery, including higher rates of perioperative complications such as deep and superficial infections. To date, however, no study has examined the relationship between preoperative BMI and outcomes of deformity surgery as measured by spine parameters such as the sagittal vertical axis (SVA), as well as health-related quality of life (HRQoL) measures such as the Oswestry Disability Index (ODI) and Scoliosis Research Society–22 patient questionnaire (SRS-22). To this end, the authors sought to clarify the relationship between BMI and postoperative change in SVA as well as HRQoL outcomes.METHODSThe authors performed a retrospective review of a prospectively managed multicenter adult spinal deformity database collected and maintained by the International Spine Study Group (ISSG) between 2009 and 2014. The primary independent variable considered was preoperative BMI. The primary outcome was the change in SVA at 1 year after deformity surgery. Postoperative ODI and SRS-22 outcome measures were evaluated as secondary outcomes. Generalized linear models were used to model the primary and secondary outcomes at 1 year as a function of BMI at baseline, while adjusting for potential measured confounders.RESULTSIncreasing BMI (compared to BMI < 18) was not associated with change of SVA at 1 year postsurgery. However, BMIs in the obese range of 30 to 34.9 kg/m2, compared to BMI < 18 at baseline, were associated with poorer outcomes as measured by the SRS-22 score (estimated change −0.47, 95% CI −0.93 to −0.01, p = 0.04). While BMIs > 30 appeared to be associated with poorer outcomes as determined by the ODI, this correlation did not reach statistical significance.CONCLUSIONSBaseline BMI did not affect the achievable SVA at 1 year postsurgery. Further studies should evaluate whether even in the absence of a change in SVA, baseline BMIs in the obese range are associated with worsened HRQoL outcomes after spinal surgery.



2021 ◽  
Author(s):  
Mahmoud Elshamly ◽  
Stefan Toegel ◽  
Josef G Grohs

Abstract BackgroundThe aim of the study was to correlate the clinical and radiological outcomes following the conservative treatment of neurologically intact patients with AO A4, A3, and A1 thoracolumbar (TL) fractures.MethodsRetrospective study included 3 cohorts of conservatively treated patients with AO A4, A3, and A1 TL fracture without the use of bracing or casting. At the final follow up segmental kyphotic angle (SKA), regional lordotic angle (RLA), lordosis gap (LG), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), and femoral obliquity angle (FOA), and the Oswestry disability index (ODI) were assessed. Data were analyzed using descriptive statistics, non-parametric inferential statistics, and Spearman correlation analyses.ResultsAge was significantly higher in A4 group than in A1 group (p=0.04). The median 1ry SKA of the A3 group (15 ± 3) was significantly higher than in A1 group (7 ± 7, p=0.04). The median of total ODI in the A4 group (42 ± 53) and A3 group (31.3 ± 27) was clinically higher than in A1 group (11.1 ± 25), however, this difference was not statistically significant. Age as well as SVA correlated significantly with PT, FOA, SKA at the follow up, and the total ODI.ConclusionAge of the patient is a significant confounder that has an important impact on the type of fracture, sagittal malalignment, its compensatory mechanisms, and the resulting clinical outcome following conservative treatment of AO A4 and A3 TL fracture.



2017 ◽  
Vol 27 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Sina Pourtaheri ◽  
Akshay Sharma ◽  
Jason Savage ◽  
Iain Kalfas ◽  
Thomas E. Mroz ◽  
...  

OBJECTIVEThe flexed posture of the proximal (L1–3) or distal (L4–S1) lumbar spine increases the diameter of the spinal canal and neuroforamina and can relieve symptoms of neurogenic claudication. Distal lumbar flexion can result in pelvic retroversion; therefore, in cases of flexible sagittal imbalance, pelvic retroversion may be compensatory for lumbar stenosis and not solely compensatory for the sagittal imbalance as previously thought. The authors investigate underlying causes for pelvic retroversion in patients with flexible sagittal imbalance.METHODSOne hundred thirty-eight patients with sagittal imbalance who underwent a total of 148 fusion procedures of the thoracolumbar spine were identified from a prospective clinical database. Radiographic parameters were obtained from images preoperatively, intraoperatively, and at 6-month and 2-year follow-up. A cohort of 24 patients with flexible sagittal imbalance was identified and individually matched with a control cohort of 23 patients with fixed deformities. Flexible deformities were defined as a 10° change in lumbar lordosis between weight-bearing and non–weight-bearing images. Pelvic retroversion was quantified as the ratio of pelvic tilt (PT) to pelvic incidence (PI).RESULTSThe average difference between lumbar lordosis on supine MR images and standing radiographs was 15° in the flexible cohort. Sixty-eight percent of the patients in the flexible cohort were diagnosed preoperatively with lumbar stenosis compared with only 22% in the fixed sagittal imbalance cohort (p = 0.0032). There was no difference between the flexible and fixed cohorts with regard to C-2 sagittal vertical axis (SVA) (p = 0.95) or C-7 SVA (p = 0.43). When assessing for postural compensation by pelvic retroversion in the stenotic patients and nonstenotic patients, the PT/PI ratio was found to be significantly greater in the patients with stenosis (p = 0.019).CONCLUSIONSFor flexible sagittal imbalance, preoperative attention should be given to the root cause of the sagittal misalignment, which could be compensation for lumbar stenosis. Pelvic retroversion can be compensatory for both the lumbar stenosis as well as for sagittal imbalance.



2018 ◽  
Vol 29 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Masayuki Miyagi ◽  
Kensuke Fukushima ◽  
Gen Inoue ◽  
Toshiyuki Nakazawa ◽  
Takayuki Imura ◽  
...  

Introduction: Patients presenting with hip diseases often have coexisting spine disorders, a condition that is termed “hip-spine syndrome.” However, few reports have evaluated total spinal alignments in patients with coxalgia. In this study, we retrospectively examined the relationship between several clinical and x-ray parameters of the hip joints and spinal alignment in patients with coxalgia. Methods: 100 patients with coxalgia (24 men, 76 women; average age, 60.0 years; age range, 16–88 years) were included. We retrospectively evaluated the following clinical and x-ray findings of hip joints and total spinal alignment: range of motion (ROM) and pain score components of the Japanese Orthopaedic Association Hip Score; leg length discrepancy (LLD); osteoarthritis (OA) stage of the hip; spinal coronal balance (Cobb angle and C7-central sacral ventral line [CSVL]); and spinal sagittal balance (sagittal vertical axis [SVA], pelvic tilt (PT), and pelvic incidence [PI]). Results: Significant positive correlations were detected between C7 - CSVL and LLD ( r = 0.35), whereas a significant negative correlation was found between SVA and hip ROM score ( r = −0.37). A significant positive correlation was also detected between SVA and OA stage of the hip ( r = 0.35). Conclusion: In the present study, large leg length discrepancy and hip pain may contribute to spinal coronal misalignment. In addition, advanced stage of OA and decreasing ROM of the hip may lead to increased spinal sagittal misalignment. These findings suggest that when evaluating spinal alignment, the progression of OA, LLD, and pain and ROM of the hip joint should be assessed.



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