Browsing by Subject "Posture"
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Item Open Access A membrane-associated progesterone-binding protein, 25-Dx, is regulated by progesterone in brain regions involved in female reproductive behaviors.(Proc Natl Acad Sci U S A, 2000-11-07) Krebs, CJ; Jarvis, ED; Chan, J; Lydon, JP; Ogawa, S; Pfaff, DWThe ventromedial hypothalamus (VMH) plays a central role in the regulation of the female reproductive behavior lordosis, a behavior dependent upon the sequential activation of receptors for the ovarian steroid hormones estradiol (E) and progesterone (P). These receptors function as transcription factors to alter the expression of target genes. To discover behaviorally relevant genes targeted by E and P in the VMH, we used the differential display PCR to identify messenger RNAs that are differentially expressed in the hypothalamus of ovariectomized (ovx) rats treated with E alone compared with ovariectomized rats treated with E and P. We show here that one interesting mRNA within the hypothalamus that is repressed by P after E priming encodes the protein 25-Dx, the rat homolog of the human membrane-associated P-binding protein Hpr6.6. Neurons in the brain containing the highest levels of 25-Dx are located in several nuclei of the basal forebrain, including the VMH. 25-Dx expression is also higher in the hypothalamus of female P receptor "knockout" mice than in their wild-type littermates. These findings suggest a mechanism in which the activation of nuclear P receptor represses expression of a membrane P receptor, 25-Dx, during lordosis facilitation.Item Open Access Coronal plane spinal malalignment and Parkinson's disease: prevalence and associations with disease severity.(The spine journal : official journal of the North American Spine Society, 2015-01) Choi, Hong June; Smith, Justin S; Shaffrey, Christopher I; Lafage, Virginie C; Schwab, Frank J; Ames, Christopher P; Matsumoto, Morio; Baik, Jong Sam; Ha, YoonBackground context
Parkinson's disease (PD) is a progressive degenerative disorder of the central nervous system. Patients with PD often present with abnormal posturing.Purpose
To investigate coronal plane deformities in patients with PD, and to evaluate the correlation between clinical features, coronal parameters related to spine alignment, and disease severity.Study design
A cross-sectional study.Patient sample
Eighty-nine patients with PD and 89 controls were included.Outcome measures
A medical history was collected from the medical records.Methods
This study was a prospective assessment of consecutive patients with PD. Clinical and demographic parameters were collected from medical records and outpatient interviews. Full-length standing anteroposterior and lateral spine radiographs were used to assess the spinal parameters. The threshold for scoliosis was set at a 10° Cobb angle, and the curve type was classified using Schwab classification.Results
A total of 178 patients (89 in PD and 89 in control groups) were included. Scoliosis was identified in 27 patients (30%) and 22 controls (p=.502). However, coronal imbalance was more common in patients with PD than in controls (11 vs. 0 patients, p=.001). Scoliosis was more common in women than in men (male:female=8:19, p=.04). Back pain was more common in patients with scoliosis than in those without scoliosis (14 of 27 vs. 17 of 62, p=.036). Schwab Type IV (thoracolumbar major) was the most common type of scoliosis in patients with PD and Type V (lumbar major) was the most common type in controls. With adjustment for patient age and gender, multiple linear regression analysis revealed that severity of PD (Unified Parkinson's Disease Rating Scale, p=.037) and magnitude of global coronal malalignment (p=.003) were associated with the scoliosis Cobb angle (p=.037, B=0.139). Direction of scoliosis and side of global coronal malalignment were not significantly correlated with the laterality of predominant PD symptoms (p>.05).Conclusions
Global coronal malalignment is more prevalent in patients with PD than in controls. Greater severity of PD was significantly associated with greater magnitude of scoliosis Cobb angle, even after adjusting for the effects of patient age and gender. However, direction of scoliosis and side of global coronal malalignment were not significantly associated with the dominant laterality of PD symptoms.Item Open Access Evolution of Adult Cervical Deformity Surgery Clinical and Radiographic Outcomes Based on a Multicenter Prospective Study: Are Behaviors and Outcomes Changing With Experience?(Spine, 2022-11) Passias, Peter G; Krol, Oscar; Moattari, Kevin; Williamson, Tyler K; Lafage, Virginie; Lafage, Renaud; Kim, Han Jo; Daniels, Alan; Diebo, Bassel; Protopsaltis, Themistocles; Mundis, Gregory; Kebaish, Khaled; Soroceanu, Alexandra; Scheer, Justin; Hamilton, D Kojo; Klineberg, Eric; Schoenfeld, Andrew J; Vira, Shaleen; Line, Breton; Hart, Robert; Burton, Douglas C; Schwab, Frank A; Shaffrey, Christopher; Bess, Shay; Smith, Justin S; Ames, Christopher P; International Spine Study GroupStudy design
Retrospective cohort study.Objective
Assess changes in outcomes and surgical approaches for adult cervical deformity surgery over time.Summary of background data
As the population ages and the prevalence of cervical deformity increases, corrective surgery has been increasingly seen as a viable treatment. Dramatic surgical advancements and expansion of knowledge on this procedure have transpired over the years, but the impact on cervical deformity surgery is unknown.Materials and methods
Adult cervical deformity patients (18 yrs and above) with complete baseline and up to the two-year health-related quality of life and radiographic data were included. Descriptive analysis included demographics, radiographic, and surgical details. Patients were grouped into early (2013-2014) and late (2015-2017) by date of surgery. Univariate and multivariable regression analyses were used to assess differences in surgical, radiographic, and clinical outcomes over time.Results
A total of 119 cervical deformity patients met the inclusion criteria. Early group consisted of 72 patients, and late group consisted of 47. The late group had a higher Charlson Comorbidity Index (1.3 vs. 0.72), more cerebrovascular disease (6% vs. 0%, both P <0.05), and no difference in age, frailty, deformity, or cervical rigidity. Controlling for baseline deformity and age, late group underwent fewer three-column osteotomies [odds ratio (OR)=0.18, 95% confidence interval (CI): 0.06-0.76, P =0.014]. At the last follow-up, late group had less patients with: a moderate/high Ames horizontal modifier (71.7% vs. 88.2%), and overcorrection in pelvic tilt (4.3% vs. 18.1%, both P <0.05). Controlling for baseline deformity, age, levels fused, and three-column osteotomies, late group experienced fewer adverse events (OR=0.15, 95% CI: 0.28-0.8, P =0.03), and neurological complications (OR=0.1, 95% CI: 0.012-0.87, P =0.03).Conclusion
Despite a population with greater comorbidity and associated risk, outcomes remained consistent between early and later time periods, indicating general improvements in care. The later cohort demonstrated fewer three-column osteotomies, less suboptimal realignments, and concomitant reductions in adverse events and neurological complications. This may suggest a greater facility with less invasive techniques.Item Open Access Evolution of postural diversity in primates as reflected by the size and shape of the medial tibial facet of the talus.(American journal of physical anthropology, 2015-05) Boyer, Doug M; Yapuncich, Gabriel S; Butler, Jared E; Dunn, Rachel H; Seiffert, Erik RComprehensive quantification of the shape and proportions of the medial tibial facet (MTF) of the talus (=astragalus) has been lacking for Primates and their closest relatives. In this study, aspects of MTF form were quantified and employed to test hypotheses about their functional and phylogenetic significance. The following hypotheses influence perceptions of primate evolutionary history but are due for more rigorous assessment: 1) A relatively large MTF distinguishes "prosimians" (strepsirrhines and tarsiers) from anthropoids and non-primate euarchontans; 2) the distinctive form of the "prosimian" MTF is a correlate of locomotor tendencies that emphasize use of vertical and small diameter supports in conjunction with inverted, abducted foot postures; and 3) the "prosimian" MTF form arose along the primate stem lineage and was present in the euprimate common ancestor.Three-dimensional (3D) scanning was used to create scale digital models of tali (n = 378 specimens, 122 species) from which three types of variables capturing aspects of MTF form were computed: 1) MTF area relative to body mass and ectal facet area; 2) MTF shape (elliptical vs. non-elliptical); and 3) MTF dorsal restriction on the talar body (i.e., extensive vs. minimal exposure of non-articular area). Data were analyzed using both phylogenetic and traditional comparative methods including Phylogenetic Generalized Least Squares, Ordinary Least Squares, ANCOVA, ANOVA, and Bayesian Ancestral State Reconstruction (ASR).Extant "prosimians" are generally distinct from anthropoids and non-primate euarchontans in our quantitative representations of MTF form. MTF area (but not shape or dorsal restriction) correlates with fibular facet angle (FFa) of the talus, which has also been argued to reflect habitual pedal inversion. Among strepsirrhines, taxa that engage in grasp-leaping more frequently/effectively appear to have a relatively larger MTF than less acrobatic taxa. Directional models of evolutionary change better describe the phylogenetic distribution of MTF variation than do other models. ASR shows 1) little change in the MTF along the primate stem, 2) independent evolution of relatively large and dorsoplantarly deep MTFs in basal haplorhines and strepsirrhines, and 3) re-evolution of morphologies similar to non-euprimates in anthropoids.Results support the hypothesis that differences in MTF form between anthropoids and "prosimians" reflect greater use of inverted foot postures and grasp-leaping in the latter group. Although fossil "prosimians" do not have the extreme MTF dimensions that characterize many extant acrobatic leapers, these variables by themselves provide little additional behavioral resolution at the level of individual fossils due to strong phylogenetic signal. ASR suggests that some specialization for use of inverted foot postures (as required in a fine-branch niche) and modifications for grasp-leaping evolved independently in basal strepsirrhine and haplorhine lineages.Item Open Access Hand and foot pressures in the aye-aye (Daubentonia madagascariensis) reveal novel biomechanical trade-offs required for walking on gracile digits.(J Exp Biol, 2010-05) Kivell, Tracy L; Schmitt, Daniel; Wunderlich, Roshna EArboreal animals with prehensile hands must balance the complex demands of bone strength, grasping and manipulation. An informative example of this problem is that of the aye-aye (Daubentonia madagascariensis), a rare lemuriform primate that is unusual in having exceptionally long, gracile fingers specialized for foraging. In addition, they are among the largest primates to engage in head-first descent on arboreal supports, a posture that should increase loads on their gracile digits. We test the hypothesis that aye-ayes will reduce pressure on their digits during locomotion by curling their fingers off the substrate. This hypothesis was tested using simultaneous videographic and pressure analysis of the hand, foot and digits for five adult aye-ayes during horizontal locomotion and during ascent and descent on a 30 degrees instrumented runway. Aye-ayes consistently curled their fingers during locomotion on all slopes. When the digits were in contact with the substrate, pressures were negligible and significantly less than those experienced by the palm or pedal digits. In addition, aye-ayes lifted their hands vertically off the substrate instead of 'toeing-off' and descended head-first at significantly slower speeds than on other slopes. Pressure on the hand increased during head-first descent relative to horizontal locomotion but not as much as the pressure increased on the foot during ascent. This distribution of pressure suggests that aye-ayes shift their weight posteriorly during head-first descent to reduce loads on their gracile fingers. This research demonstrates several novel biomechanical trade-offs to deal with complex functional demands on the mammalian skeleton.Item Open Access Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins.(Proceedings of the National Academy of Sciences of the United States of America, 2018-04-02) Kozma, Elaine E; Webb, Nicole M; Harcourt-Smith, William EH; Raichlen, David A; D'Août, Kristiaan; Brown, Mary H; Finestone, Emma M; Ross, Stephen R; Aerts, Peter; Pontzer, HermanThe evolutionary emergence of humans' remarkably economical walking gait remains a focus of research and debate, but experimentally validated approaches linking locomotor capability to postcranial anatomy are limited. In this study, we integrated 3D morphometrics of hominoid pelvic shape with experimental measurements of hip kinematics and kinetics during walking and climbing, hamstring activity, and passive range of hip extension in humans, apes, and other primates to assess arboreal-terrestrial trade-offs in ischium morphology among living taxa. We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing.Item Open Access Predicting the combined occurrence of poor clinical and radiographic outcomes following cervical deformity corrective surgery.(Journal of neurosurgery. Spine, 2019-11) Horn, Samantha R; Passias, Peter G; Oh, Cheongeun; Lafage, Virginie; Lafage, Renaud; Smith, Justin S; Line, Breton; Anand, Neel; Segreto, Frank A; Bortz, Cole A; Scheer, Justin K; Eastlack, Robert K; Deviren, Vedat; Mummaneni, Praveen V; Daniels, Alan H; Park, Paul; Nunley, Pierce D; Kim, Han Jo; Klineberg, Eric O; Burton, Douglas C; Hart, Robert A; Schwab, Frank J; Bess, Shay; Shaffrey, Christopher I; Ames, Christopher P; International Spine Study GroupOBJECTIVE:Cervical deformity (CD) correction is clinically challenging. There is a high risk of developing complications with these highly complex procedures. The aim of this study was to use baseline demographic, clinical, and surgical factors to predict a poor outcome following CD surgery. METHODS:The authors performed a retrospective review of a multicenter prospective CD database. CD was defined as at least one of the following: cervical kyphosis (C2-7 Cobb angle > 10°), cervical scoliosis (coronal Cobb angle > 10°), C2-7 sagittal vertical axis (cSVA) > 4 cm, or chin-brow vertical angle (CBVA) > 25°. Patients were categorized based on having an overall poor outcome or not. Health-related quality of life measures consisted of Neck Disability Index (NDI), EQ-5D, and modified Japanese Orthopaedic Association (mJOA) scale scores. A poor outcome was defined as having all 3 of the following categories met: 1) radiographic poor outcome: deterioration or severe radiographic malalignment 1 year postoperatively for cSVA or T1 slope-cervical lordosis mismatch (TS-CL); 2) clinical poor outcome: failing to meet the minimum clinically important difference (MCID) for NDI or having a severe mJOA Ames modifier; and 3) complications/reoperation poor outcome: major complication, death, or reoperation for a complication other than infection. Univariate logistic regression followed by multivariate regression models was performed, and internal validation was performed by calculating the area under the curve (AUC). RESULTS:In total, 89 patients with CD were included (mean age 61.9 years, female sex 65.2%, BMI 29.2 kg/m2). By 1 year postoperatively, 18 (20.2%) patients were characterized as having an overall poor outcome. For radiographic poor outcomes, patients' conditions either deteriorated or remained severe for TS-CL (73% of patients), cSVA (8%), horizontal gaze (34%), and global SVA (28%). For clinical poor outcomes, 80% and 60% of patients did not reach MCID for EQ-5D and NDI, respectively, and 24% of patients had severe symptoms (mJOA score 0-11). For the complications/reoperation poor outcome, 28 patients experienced a major complication, 11 underwent a reoperation, and 1 had a complication-related death. Of patients with a poor clinical outcome, 75% had a poor radiographic outcome; 35% of poor radiographic and 37% of poor clinical outcome patients had a major complication. A poor outcome was predicted by the following combination of factors: osteoporosis, baseline neurological status, use of a transition rod, number of posterior decompressions, baseline pelvic tilt, T2-12 kyphosis, TS-CL, C2-T3 SVA, C2-T1 pelvic angle (C2 slope), global SVA, and number of levels in maximum thoracic kyphosis. The final model predicting a poor outcome (AUC 86%) included the following: osteoporosis (OR 5.9, 95% CI 0.9-39), worse baseline neurological status (OR 11.4, 95% CI 1.8-70.8), baseline pelvic tilt > 20° (OR 0.92, 95% CI 0.85-0.98), > 9 levels in maximum thoracic kyphosis (OR 2.01, 95% CI 1.1-4.1), preoperative C2-T3 SVA > 5.4 cm (OR 1.01, 95% CI 0.9-1.1), and global SVA > 4 cm (OR 3.2, 95% CI 0.09-10.3). CONCLUSIONS:Of all CD patients in this study, 20.2% had a poor overall outcome, defined by deterioration in radiographic and clinical outcomes, and a major complication. Additionally, 75% of patients with a poor clinical outcome also had a poor radiographic outcome. A poor overall outcome was most strongly predicted by severe baseline neurological deficit, global SVA > 4 cm, and including more of the thoracic maximal kyphosis in the construct.Item Open Access Prevalence and type of cervical deformities among adults with Parkinson's disease: a cross-sectional study.(Journal of neurosurgery. Spine, 2016-04) Moon, Bong Ju; Smith, Justin S; Ames, Christopher P; Shaffrey, Christopher I; Lafage, Virginie; Schwab, Frank; Matsumoto, Morio; Baik, Jong Sam; Ha, YoonObject
To identify the characteristics of cervical deformities in Parkinson's disease (PD) and the role of severity of PD in the development of cervical spine deformities, the authors investigated the prevalence of the cervical deformities, cervical kyphosis (CK), and cervical positive sagittal malalignment (CPSM) in patients with PD. They also analyzed the association of severity of cervical deformities with the stage of PD in the context of global sagittal spinopelvic alignment.Methods
This study was a prospective assessment of consecutively treated patients (n = 89) with PD. A control group of the age- and sex-matched patients was selected from patients with degenerative cervical spine disease but without PD. Clinical and demographic parameters including age, sex, duration of PD, and Hoehn and Yahr (H&Y) stage were collected. Full-length standing radiographs were used to assess spinopelvic parameters. CK was defined as a C2-7 Cobb angle < 0°. CPSM was defined as C2-7 sagittal vertical axis (SVA) > 4 cm.Results
A significantly higher prevalence of CPSM (28% vs. 1.1%, p < 0.001), but not CK (12% vs. 10.1%, p = 0.635), was found in PD patients compared with control patients. Among patients with PD, those with CK were younger (62.1 vs. 69.0 years, p = 0.013) and had longer duration of PD (56.4 vs. 36.2 months, p = 0.034), but the severity of PD was not significantly different. Logistic regression analysis revealed that the presence of CK was associated with younger age, higher mismatch between pelvic incidence and lumbar lordosis, and lower C7-S1 SVA. The patients with CPSM had significantly greater thoracic kyphosis (TK) (p < 0.001) and a trend toward more advanced H&Y stage (p = 0.05). Logistic regression analysis revealed that CPSM was associated with male sex, greater TK, and more advanced H&Y stage.Conclusions
Patients with PD have a significantly higher prevalence of CPSM compared with age- and sex-matched control patients with cervical degenerative disease but without PD. Among patients with PD, CK is not associated with the severity of PD but is associated with overall global sagittal malalignment. In contrast, the presence of CPSM is associated more with the severity of PD than it is with the presence of global sagittal malalignment. Collectively, these data suggest that the neuromuscular pathogenesis of PD may affect the development of CPSM more than of CK.Item Open Access Primary Drivers of Adult Cervical Deformity: Prevalence, Variations in Presentation, and Effect of Surgical Treatment Strategies on Early Postoperative Alignment.(Neurosurgery, 2018-10) Passias, Peter G; Jalai, Cyrus M; Lafage, Virginie; Lafage, Renaud; Protopsaltis, Themistocles; Ramchandran, Subaraman; Horn, Samantha R; Poorman, Gregory W; Gupta, Munish; Hart, Robert A; Deviren, Vedat; Soroceanu, Alexandra; Smith, Justin S; Schwab, Frank; Shaffrey, Christopher I; Ames, Christopher P; International Spine Study Group (Littleton, Colorado)Background
Primary drivers (PDs) of adult cervical deformity (ACD) have not been described in relation to pre- and early postoperative alignment or degree of correction.Objective
To define the PDs of ACD to understand the impact of driver region on global postoperative compensatory mechanisms.Methods
Primary cervical deformity driver/vertebral apex level were determined: CS = cervical; CTJ = cervicothoracic junction; TH = thoracic; SP = spinopelvic. Patients were evaluated if surgery included PD apex, based on the lowest instrumented vertebra (LIV): CS: LIV ≤ C7, CTJ: LIV ≤ T3, TH: LIV ≤ T12. Cervical and thoracolumbar alignment was measured preoperatively and 3 mo (3M) postoperatively. PD groups were compared with analysis of variance/Pearson χ2, paired t-tests.Results
Eighty-four ACD patients met inclusion criteria. Thoracic drivers (n = 26) showed greatest preoperative cervical and global malalignment against other PD: higher thoracic kyphosis, pelvic incidence-lumbar lordosis (PI-LL), T1 slope C2-T3 sagittal vertical axis (SVA), and C0-2 angle (P < .05). Differences in baseline-3M alignment changes were observed between surgical PD groups, in PI-LL, LL, T1 slope minus cervical lordosis (TS-CL), cervical SVA, C2-T3 SVA (P < .05). Main changes were between TH and CS driver groups: TH patients had greater PI-LL (4.47° vs -0.87°, P = .049), TS-CL (-19.12° vs -4.30, P = .050), C2-C7 SVA (-18.12 vs -4.30 mm, P = .007), and C2-T3 SVA (-24.76 vs 8.50 mm, P = .002) baseline-3M correction. CTJ drivers trended toward greater LL correction compared to CS drivers (-6.00° vs 0.88°, P = .050). Patients operated at CS driver level had a difference in the prevalence of 3M TS-CL modifier grades (0 = 35.7%, 1 = 0.0%, 2 = 13.3%, P = .030). There was a significant difference in 3M chin-brow vertical angle modifier grade distribution in TH drivers (0 = 0.0%, 1 = 35.9%, 2 = 14.3%, P = .049).Conclusion
Characterizing ACD patients by PD type reveals differences in pre- and postoperative alignment. Evaluating surgical alignment outcomes based on PD inclusion is important in understanding alignment goals for ACD correction.Item Open Access Testing parallel laser image scaling for remotely measuring body dimensions on mantled howling monkeys (Alouatta palliata).(Am J Primatol, 2015-08) Barrickman, Nancy L; Schreier, Amy L; Glander, Kenneth EBody size is a fundamental variable for many studies in primate biology. However, obtaining body dimensions of wild primates through live capture is difficult and costly, so developing an alternative inexpensive and non-invasive method is crucial. Parallel laser image scaling for remotely measuring body size has been used with some success in marine and terrestrial animals, but only one arboreal primate. We further tested the efficacy of this method on the arboreal mantled howling monkey (Alouatta palliata) in La Pacifica, Costa Rica. We calculated interobserver error, as well as the method's repeatability when measuring the same animal on different occasions. We also compared measurements obtained physically through live capture with measurements obtained remotely using parallel laser image scaling. Our results show that the different types of error for the remote technique are minimal and comparable with the error rates observed in physical methods, with the exception of some dimensions that vary depending on the animals' posture. We conclude that parallel laser image scaling can be used to remotely obtain body dimensions if careful consideration is given to factors such as species-specific morphology and postural habits.Item Open Access The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery.(Neurosurgery, 2012-09) Tang, Jessica A; Scheer, Justin K; Smith, Justin S; Deviren, Vedat; Bess, Shay; Hart, Robert A; Lafage, Virginie; Shaffrey, Christopher I; Schwab, Frank; Ames, Christopher P; ISSGBackground
Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion.Objective
To evaluate the relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion.Methods
From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-related quality-of-life scores.Results
Both C2-C7 SVA and CGH-C7 SVA negatively correlated with SF-36 physical component scores (r = -0.43, P < .001 and r = -0.36, P = .005, respectively). C2-C7 SVA positively correlated with NDI scores (r = 0.20, P = .036). C2-C7 SVA positively correlated with C1-C2 lordosis (r = 0.33, P = .001). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of approximately 40 mm, beyond which correlations were most significant.Conclusion
Our findings demonstrate that, similar to the thoracolumbar spine, the severity of disability increases with positive sagittal malalignment following surgical reconstruction.Item Open Access The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery.(Neurosurgery, 2015-03) Tang, Jessica A; Scheer, Justin K; Smith, Justin S; Deviren, Vedat; Bess, Shay; Hart, Robert A; Lafage, Virginie; Shaffrey, Christopher I; Schwab, Frank; Ames, Christopher P; ISSGBackground
Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion.Objective
To evaluate the relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion.Methods
From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-related quality-of-life scores.Results
Both C2-C7 SVA and CGH-C7 SVA negatively correlated with SF-36 physical component scores (r =-0.43, P< .001 and r =-0.36, P = .005, respectively). C2-C7 SVA positively correlated with NDI scores (r = 0.20, P = .036). C2-C7 SVA positively correlated with C1-C2 lordosis (r = 0.33, P = .001). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of approximately 40 mm, beyond which correlations were most significant.Conclusion
Our findings demonstrate that, similar to the thoracolumbar spine, the severity of disability increases with positive sagittal malalignment following surgical reconstruction.