Measurement of spinal kyphosis: implications for the management of Scheuermann's kyphosis

The association between the kyphosis angle and physical performance in community-dwelling older adults

BACKGROUND

We investigated prospectively among community-dwelling older adults aged 65 years and over whether a larger kyphosis angle is associated with poorer physical performance (balance, muscle strength or both), and whether this association is unidirectional.

METHODS

ale and female participants performed a multicomponent physical performance test with subscores for gait, muscle strength and balance at baseline and after 2 years. Hand grip strength was also measured at baseline and at follow-up. The Cobb angle was measured on DXA-based Vertebral Fracture Assessments, made at the baseline and follow-up visit. Through linear and logistic regression analysis, we investigated the association between the kyphosis angle and physical performance and vice versa. We stratified for sex, and tested for effect modification by age and study center.

RESULTS

The mean kyphosis angle was 37° and 15% of the participants (n=1220, mean age 72.9±5.7 years) had hyperkyphosis (Cobb angle ≥50°). A larger kyphosis angle at baseline was independently associated with a poorer total physical performance score in women of the oldest quartile (≥77 years) in both the cross-sectional and longitudinal analyses (baseline B-0.32, 95%CI -0.56--0.08; follow-up B 0.32, 95%CI -0.55--0.10). There was no association between physical performance at baseline and kyphosis progression.

CONCLUSIONS

A larger kyphosis angle is independently associated with a poorer physical performance at baseline and over time, and the direction of this association is unidirectional. These results emphasize the importance of early detection and treatment of hyperkyphosis to prevent further worsening of the kyphosis angle, thereby potentially preserving physical performance.

The association between hyperkyphosis and fall incidence among community-dwelling older adults

Hyperkyphosis, an increased kyphosis angle of the thoracic spine, was associated with a higher fall incidence in the oldest quartile of a large prospective cohort of community-dwelling older adults. Hyperkyphosis could serve as an indicator of an increased fall risk as well as a treatable condition.

INTRODUCTION

Hyperkyphosis is frequently found in adults aged 65 years and older and may be associated with falls. We aimed to investigate prospectively in community-dwelling older adults whether hyperkyphosis or change in the kyphosis angle is associated with fall incidence.

METHODS

Community-dwelling older adults (n = 1220, mean age 72.9 ± 5.7 years) reported falls weekly over 2 years. We measured thoracic kyphosis through the Cobb angle between the fourth and 12th thoracic vertebra on DXA-based vertebral fracture assessments and defined hyperkyphosis as a Cobb angle ≥ 50°. The change in the Cobb angle during follow-up was dichotomized (< 5 or ≥ 5°). Through multifactorial regression analysis, we investigated the association between the kyphosis angle and falls.

RESULTS

Hyperkyphosis was present in 15% of the participants. During follow-up, 48% of the participants fell at least once. In the total study population, hyperkyphosis was not associated with the number of falls (adjusted IRR 1.12, 95% CI 0.91-1.39). We observed effect modification by age (p = 0.002). In the oldest quartile, aged 77 years and older, hyperkyphosis was prospectively associated with a higher number of falls (adjusted IRR 1.67, 95% CI 1.14-2.45). Change in the kyphosis angle was not associated with fall incidence.

CONCLUSIONS

Hyperkyphosis was associated with a higher fall incidence in the oldest quartile of a large prospective cohort of community-dwelling older adults. Because hyperkyphosis is a partially reversible condition, we recommend investigating whether hyperkyphosis is one of the causes of falls and whether a decrease in the kyphosis angle may contribute to fall prevention.

Radiophobia Overreaction: College of Chiropractors of British Columbia Revoke Full X-Ray Rights Based on Flawed Study and Radiation Fear-Mongering

Fears over radiation have created irrational pressures to dissuade radiography use within chiropractic. Recently, the regulatory body for chiropractors practicing in British Columbia, Canada, the College of Chiropractors of British Columbia (CCBC), contracted Pierre Côté to review the clinical use of X-rays within the chiropractic profession. A "rapid review" was performed and published quickly and included only 9 papers, the most recent dating from 2005; they concluded, "Given the inherent risks of radiation, we recommend that chiropractors do not use radiographs for the routine and repeat evaluation of the structure and function of the spine." The CCBC then launched an immediate review of the use of X-rays by chiropractors in their jurisdiction. Member and public opinion were gathered but not presented to their members. On February 4, 2021, the College announced amendments to their Professional Conduct Handbook that revoked X-ray rights for routine/repeat assessment and management of patients with spine disorders. Here, we highlight current and historical evidence that substantiates that X-rays are not a public health threat. We also point out critical and insurmountable flaws in the single paper used to support irrational and unscientific policy that discriminates against chiropractors who practice certain forms of evidence-based X-ray-guided methods.

The Clinical Relevance of Hyperkyphosis: A Narrative Review

The kyphosis angle of the thoracic spine tends to increase with aging. Hyperkyphosis is a kyphosis angle, exceeding the normal range. This narrative literature review aims to provide an overview of the current literature concerning kyphosis measurement methods, the etiology and adverse health effects of hyperkyphosis. As of yet, a well-defined threshold for hyperkyphosis is lacking. To attain more generalizability and to be able to compare study results in older adults, we propose to define age-related hyperkyphosis as a Cobb angle of 50° or more in standing position. Hyperkyphosis may be a potentially modifiable risk factor for adverse health outcomes, like fall risk and fractures. Additionally, hyperkyphosis may indicate the presence of osteoporosis, which is treatable. Prospective and intervention studies, using a Cobb angle of 50° as a clear and uniform definition of hyperkyphosis, are warranted to investigate the clinical relevance of hyperkyphosis.

Can MRI Predict Flexibility in Scheuermann Kyphosis Patients?

STUDY DESIGN

Retrospective, blinded analysis of imaging studies.

OBJECTIVE

The aim of this study is compare the use of magnetic resonance imaging (MRI) to lateral radiograph using bolster in the evaluation of Scheuermann kyphosis (SK) curve flexibility measurement.

SUMMARY AND BACKGROUND DATA

The flexibility of the thoracic curve [thoracic kyphosis (TK)] in SK is of primary importance in its preoperative planning. Several methods have been described for SK curve flexibility measurement. The most commonly used method is lateral hyperextension radiography on hard bolster [hyperextension radiograph (HE)]. No current methods use MRI for flexibility assessment.

MATERIALS AND METHODS

Flexibility of TK in SK patients was measured as a difference between standing radiograph and bolster-assisted lateral HE or supine MRI. The sagittal Cobb angle of the TK was measured between the superior endplate of T4 and the inferior endplate of T12 vertebral body. Flexibilities measured by these 2 methods were compared and analyzed using the generalized estimating equation analysis and the correlation analysis.

RESULTS

We assessed 18 SK patients (14 males and 4 females) with mean age of 20.06±6.03 years. The standing TK x-rays showed 83.8±6.1 degrees. On HE, TK curve reduced by 39.3 degrees (95% confidence interval, 35.8-42.9) to 44.5±6.2 degrees (P<0.001). Preoperative MRI images showed TK of 53.8±5.9 degrees which means reduction by 30 degrees (95% confidence interval, 26.6-33.4) from the standing radiographs (P<0.001). Linear dependency between HE and MRI flexibility with a mean difference of 9.3 degrees was found (R=0.61, P<0.001).

CONCLUSIONS

Our study shows that preoperative MRI can be used for SK flexibility assessment with similar predictive value as routinely used bolster-assisted hyperextension lateral radiograph. Consequently, patient exposure to preoperative hyperextension ionizing radiation may be reduced.

Agreement between fiber optic and optoelectronic systems for quantifying sagittal plane spinal curvature in sitting

Spinal posture affects how individuals function from a manual wheelchair. There is a need to directly quantify spinal posture in this population to ultimately improve function. A fiber optic system, comprised of an attached series of sensors, is promising for measuring large regions of the spine in individuals sitting in a wheelchair. The purpose of this study was to determine the agreement between fiber optic and optoelectronic systems for measuring spinal curvature, and describe the range of sagittal plane spinal curvatures in natural sitting. Able-bodied adults (n = 26, 13 male) participated. Each participant assumed three sitting postures: natural, slouched (accentuated kyphosis), and extension (accentuated lordosis) sitting. Fiber optic (ShapeTape) and optoelectronic (Optotrak) systems were applied to the skin over spinous processes from S1 to C7 and used to measure sagittal plane spinal curvature. Regions of kyphosis and lordosis were identified. A Cobb angle-like method was used to quantify lordosis and kyphosis. Generalized linear model and Bland-Altman analyses were used to assess agreement. A strong correlation exists between curvature values obtained with Optotrak and ShapeTape (R(2) = 0.98). The mean difference between Optotrak and ShapeTape for kyphosis in natural, extension, and slouched postures was 4.30° (95% LOA: -3.43 to 12.04°), 3.64° (95% LOA: -1.07 to 8.36°), and 4.02° (95% LOA: -2.80 to 10.84°), respectively. The mean difference for lordosis, when present, in natural and extension postures was 2.86° (95% LOA: -1.18 to 6.90°) and 2.55° (95% LOA: -3.38 to 8.48°), respectively. In natural sitting, the mean ± SD of kyphosis values was 35.07 ± 6.75°. Lordosis was detected in 8/26 participants: 11.72 ± 7.32°. The fiber optic and optoelectronic systems demonstrate acceptable agreement for measuring sagittal plane thoracolumbar spinal curvature.

Comparison of scoliosis measurements based on three-dimensional vertebra vectors and conventional two-dimensional measurements: advantages in evaluation of prognosis and surgical results

PURPOSE

A new concept of vertebra vectors based on spinal three-dimensional (3D) reconstructions of images from the EOS system, a new low-dose X-ray imaging device, was recently proposed to facilitate interpretation of EOS 3D data, especially with regard to horizontal plane images. This retrospective study was aimed at the evaluation of the spinal layout visualized by EOS 3D and vertebra vectors before and after surgical correction, the comparison of scoliotic spine measurement values based on 3D vertebra vectors with measurements using conventional two-dimensional (2D) methods, and an evaluation of horizontal plane vector parameters for their relationship with the magnitude of scoliotic deformity.

METHODS

95 patients with adolescent idiopathic scoliosis operated according to the Cotrel-Dubousset principle were subjected to EOS X-ray examinations pre- and postoperatively, followed by 3D reconstructions and generation of vertebra vectors in a calibrated coordinate system to calculate vector coordinates and parameters, as published earlier. Differences in values of conventional 2D Cobb methods and methods based on vertebra vectors were evaluated by means comparison T test and relationship of corresponding parameters was analysed by bivariate correlation. Relationship of horizontal plane vector parameters with the magnitude of scoliotic deformities and results of surgical correction were analysed by Pearson correlation and linear regression.

RESULTS

In comparison to manual 2D methods, a very close relationship was detectable in vertebra vector-based curvature data for coronal curves (preop r 0.950, postop r 0.935) and thoracic kyphosis (preop r 0.893, postop r 0.896), while the found small difference in L1-L5 lordosis values (preop r 0.763, postop r 0.809) was shown to be strongly related to the magnitude of corresponding L5 wedge. The correlation analysis results revealed strong correlation between the magnitude of scoliosis and the lateral translation of apical vertebra in horizontal plane. The horizontal plane coordinates of the terminal and initial points of apical vertebra vectors represent this (r 0.701; r 0.667). Less strong correlation was detected in the axial rotation of apical vertebras and the magnitudes of the frontal curves (r 0.459).

CONCLUSIONS

Vertebra vectors provide a key opportunity to visualize spinal deformities in all three planes simultaneously. Measurement methods based on vertebral vectors proved to be just as accurate and reliable as conventional measurement methods for coronal and sagittal plane parameters. In addition, the horizontal plane display of the curves can be studied using the same vertebra vectors. Based on the vertebra vectors data, during the surgical treatment of spinal deformities, the diminution of the lateral translation of the vertebras seems to be more important in the results of the surgical correction than the correction of the axial rotation.

Kyphectomy in children with myelomeningocele

BACKGROUND

Patients with myelomeningocele and rigid lumbar and thoracolumbar kyphosis face substantial functional difficulties with sitting and lying supine and are prone to skin breakdown over the gibbus and risk of infection. Kyphectomy, along with cordotomy and segmental spinal instrumentation down to the pelvis, is one alternative that can provide reliable correction of the deformity but also can maintain that correction over a period of time.

QUESTIONS/PURPOSES

We determined the fusion rates, deformity correction and maintenance, and perioperative complications of kyphectomy with long segmental spinal instrumentation using the Warner and Fackler technique.

METHODS

We retrospectively reviewed the charts and radiographs of 33 patients with myelomeningocele who had kyphectomy with segmental spinal instrumentation down to the pelvis between 1991 and 2006. The average age at surgery was 7.6 years (range, 3-19 years). Twenty-one patients had a minimum 2-year followup (average, 7.0 years; range, 2.4-15.7 years).

RESULTS

The average preoperative kyphosis of 124° (range, 75°-210°) improved at last followup to 22° (range, 3°-55°) with an average correction of 81% (range, 59%-98%). We identified 17 postoperative complications. Wound and skin complications were most common; 11 secondary surgeries were performed in 10 patients.

CONCLUSIONS

Surgery for myelomeningocele kyphosis is technically demanding and carries substantial risk. Kyphectomy and posterior spinal fusion and instrumentation with the Warner and Fackler technique allow correction and maintenance of sagittal alignment.

Comparação entre dois métodos de posicionamento para realização do raio X e sua repercussão na avaliação da cifose torácica utilizando o método de Cobb e no equilíbrio sagital

INTRODUÇÃO: o tratamento da cifose torácica é baseado na aferição da magnitude da curva baseada em mensurações radiográficas, e proporcionar o correto equilíbrio sagital pela correção cirúrgica de uma gibosidade é de importância fundamental. OBJETIVO: análise radiográfica prospectiva do efeito da variação da posição dos braços sobre a aferição da cifose torácica e do equilíbrio sagital entre pacientes com idades pré-estabelecidas. MÉTODOS: foram realizadas radiografias na posição lateral da coluna vertebral utilizando-se dois métodos posicionais: posição 1, em que o paciente permanecia de pé, com os joelhos juntos, pés alinhados com os ombros, cabeça reta direcionada para a frente, braços estendidos a 90º em relação ao tronco, mantendo os membros superiores estendidos e paralelos ao chão; uma segunda radiografia foi obtida com o paciente de pé, com os joelhos juntos, pés alinhados com os ombros, cabeça reta direcionada para a frente, com os cotovelos fletidos e os dedos repousando sobre a fossa supraclavicular bilateralmente. Os braços devem formar um ângulo de aproximadamente 45º com o corpo. Foram mensurados os ângulos de Cobb e o equilíbrio sagital nas duas radiografias. RESULTADOS: não houve correlação entre a posição dos braços, os valores angulares de Cobb e o equilíbrio sagital. CONCLUSÃO: em nosso trabalho, observamos que a posição dos braços (90º versus 45º), não interfere estatisticamente no valor da cifose torácica e na variação do equilíbrio sagital.

Inter- and intra-observer reliability of the Cobb angle in the measurement of vertebral, local and segmental kyphosis of traumatic lumbar spine fractures in the lateral X-ray

INTRODUCTION

Measurement of the vertebral, local and segmental kyphosis according to Cobb is a standard procedure in the assessment of traumatic, idiopathic and degenerative spinal deformities. The purpose of this study was to evaluate the inter- and intra-observer reliability of these three radiological angles on the basis of lateral X-rays in lumbar spine fractures with spinal kyphosis.

PATIENTS AND METHODS

A consecutive series of 88 patients with traumatic lumbar spine fractures with kyphotic deformities were included in the study. All patients were younger that 50 years of age and had an adequate trauma leading to the fracture. Three independent observers with different levels of clinical training measured the vertebral, segmental and local kyphosis of these patients on the basis of lateral X-rays. The readings were repeated 4 weeks later to assess intra-observer reliability.

RESULTS

The most common injury mechanism was a fall from a height of more than 3 m. The first lumbar vertebra was the most commonly affected. Mean inter- and intra-observer reliabilities were good for the vertebral (mean ICC: 0.6607; mean ICC: 0.6979) and local (mean ICC: 0.7778; mean ICC: 0.7642) kyphosis and excellent (mean ICC: 0.8129; mean ICC: 0.8103) for the segmental kyphosis.

CONCLUSION

In this study, the segmental-, vertebral-, and local kyphosis angle according to Cobb showed sufficient inter- and intra-observer reliability for the use in daily practice and scientific studies.

Validation of the flexible electrogoniometer for measuring thoracic kyphosis

STUDY DESIGN

Three experiments to validate the use of the flexible electrogoniometer (FEG) as a tool to measure thoracic kyphosis.

OBJECTIVE

To investigate the accuracy, test-retest reliability, and concurrent validity of the FEG as applied to the thoracic spine.

SUMMARY OF BACKGROUND DATA

Thoracic kyphosis is commonly measured by the Cobb angle from lateral radiograph. Other less-invasive tools have been developed, but all yield only static measurements or are restricted to the laboratory. The FEG, which can record joint angles over time outside the laboratory, has been used to measure other joints but has not yet been validated for measurement of the thoracic spine.

METHODS

First, the FEG was bench-tested against a plurimeter for accuracy. Second, 12 subjects performed 7 functional activities 1 week apart to assess the test-retest reliability. Finally, to examine concurrent validity, 12 subjects underwent radiography in "upright" and "slumped" standing with the FEG attached to the skin over their thoracic spine. Three Cobb angles, which corresponded with the inner, mid, and outer margins, respectively, of the overlying FEG end blocks were compared with the FEG angles.

RESULTS

The correlation between the FEG and the plurimeter was excellent (r > 0.99, P < 0.0001), although some accuracy was lost at extremes of range. The mean correlation between the first and second measurements was very strong (intraclass correlation coefficient(2,1) 0.92, P < 0.0001; range, 0.89-0.95). The mid-Cobb angle showed the least absolute angular difference from, and was highly correlated with, the FEG angle (r = 0.81, P < 0.01).

CONCLUSION

The FEG demonstrated excellent accuracy and test-retest reliability and correlated very well with the Cobb angle. The FEG measurement seemed to correspond most closely with the Cobb angle measured between the middle of the FEG end blocks.

Inter- and intraobserver reliability of the vertebral, local and segmental kyphosis in 120 traumatic lumbar and thoracic burst fractures: evaluation in lateral X-rays and sagittal computed tomographies

Evaluation of the kyphosis angle in thoracic and lumbar burst fractures is often used to indicate surgical procedures. The kyphosis angle could be measured as vertebral, segmental and local kyphosis according to the method of Cobb. The vertebral, segmental and local kyphosis according to the method of Cobb were measured at 120 lateral X-rays and sagittal computed tomographies of 60 thoracic and 60 lumbar burst fractures by 3 independent observers on 2 separate occasions. Osteoporotic fractures were excluded. The intra- and interobserver reliability of these angles in X-ray and computed tomogram, using the intra class correlation coefficient (ICC) were evaluated. Highest reproducibility showed the segmental kyphosis followed by the vertebral kyphosis. For thoracic fractures segmental kyphosis shows in X-ray "excellent" inter- and intraobserver reliabilities (ICC 0.826, 0.802) and for lumbar fractures "good" to "excellent" inter- and intraobserver reliabilities (ICC = 0.790, 0.803). In computed tomography, the segmental kyphosis showed "excellent" inter- and intraobserver reliabilities (ICC = 0.824, 0.801) for thoracic and "excellent" inter- and intraobserver reliabilities (ICC = 0.874, 0.835) for the lumbar fractures. Regarding both diagnostic work ups (X-ray and computed tomography), significant differences were evaluated in interobserver reliabilities for vertebral kyphosis measured in lumbar fracture X-rays (p = 0.035) and interobserver reliabilities for local kyphosis, measured in thoracic fracture X-rays (p = 0.010). Regarding both fracture localizations (thoracic and lumbar fractures), significant differences could only be evaluated in interobserver reliabilities for the local kyphosis measured in computed tomographies (p = 0.045) and in intraobserver reliabilities for the vertebral kyphosis measured in X-rays (p = 0.024). "Good" to "excellent" inter- and intraobserver reliabilities for vertebral, segmental and local kyphosis in X-ray make these angles to a helpful tool, indicating surgical procedures. For the practical use in lateral X-ray, we emphasize the determination of the segmental kyphosis, because of the highest reproducibility of this angle. "Good" to "excellent" inter- and intraobserver reliabilities for these three angles could also be evaluated in computed tomographies. Therefore, also in computed tomography, the use of these three angles seems to be generally possible. For a direct correlation of the results in lateral X-ray and in computed tomography, further studies should be needed.

A review of methods for quantitative evaluation of spinal curvature

The aim of this paper is to provide a complete overview of the existing methods for quantitative evaluation of spinal curvature from medical images, and to summarize the relevant publications, which may not only assist in the introduction of other researchers to the field, but also be a valuable resource for studying the existing methods or developing new methods and evaluation strategies. Key evaluation issues and future considerations, supported by the results of the overview, are also discussed.

Restoration of thoracic kyphosis by posterior instrumentation in adolescent idiopathic scoliosis: comparative radiographic analysis of two methods of reduction

STUDY DESIGN

A retrospective comparison of radiographic results for 2 consecutive series of patients treated for adolescent idiopathic scoliosis (AIS) by posterior instrumentations with thoracic screws using 2 methods of reduction: sequential approximation by cantilever reduction (CR) and simultaneous translation technique on 2 rods (ST2R).

OBJECTIVE

To compare correction of thoracic hypokyphosis and coronal radiographic results between the 2 methods of reduction.

SUMMARY OF BACKGROUND DATA

Publications concerning AIS confirm the moderate correction of thoracic hypokyphosis by posterior instrumentation with hooks and also with pedicle screws.

METHODS

Forty-four patients with AIS (Lenke type 1, 2, 3) underwent a posterior spinal fusion and instrumentation (CR series: 21 patients--ST2R series: 23 patients). Three groups of preoperative kyphosis were generated: 12 patients with severe hypokyphosis (<or=10 degrees ) (5 in CR series and 7 in ST2R series); 12 patients with mild hypokyphosis (10-20 degrees ) (5 and 7 patients, respectively) and 20 with normal kyphosis (>20 degrees ) (11 and 9 patients, respectively). Thoracic kyphosis (T4-T12) and Cobb angle measurements of major and minor curves were evaluated by an independent observer. The minimum follow-up was 2 years.

RESULTS

At final follow-up, regarding patients with a severe preoperative hypokyphosis, the mean gain was 14 degrees in the CR series (8 degrees preoperative-22 degrees postoperative) and 27 degrees in the ST2R series (3-30 degrees ) (P = 0.018). Concerning patients with mild hypokyphosis, the mean gains were, respectively, 8 degrees (17-25 degrees ) and 18 degrees (16-34 degrees ) (P = 0.052). After surgery, 3 patients of CR series had hypokyphosis whereas the patients of the ST2R series all had normal kyphosis. In coronal plane, the mean correction of scoliosis was similar for both groups (75% vs. 69%; P = 0.177).

CONCLUSION

Simultaneous translation on 2 rods provides a better correction of thoracic kyphosis than the sequential approximation by CR on patients with preoperative hypokyphosis. This surgical technique restores normal thoracic kyphosis in all cases.

Pediatric scoliosis and kyphosis

Pediatric spinal deformity is a common manifestation of multiple disorders. The clinical picture varies depending on the age at presentation, the severity of the curve at the time of diagnosis, and the underlying cause. Knowledge of the natural history of these varied conditions, the dynamics of growth in the developing spine, and normal axial skeletal biomechanics are fundamental in planning an appropriate treatment. Furthermore, in many instances the spinal anomaly is just part of the problem in a globally affected patient. Treatment alternatives must be judged based on their capacity to positively alter the natural course of the disease and provide a long-standing solution into a patient's adulthood.

Radiographic measurement of the sagittal plane deformity in patients with osteoporotic spinal fractures evaluation of intrinsic error

Cobb method has been shown to be the most reliable technique with a reasonable measurement error to determine the kyphosis in fresh fractures of young patients. However, measurement errors may be higher for elderly patients as it may be difficult to determine the landmarks due to osteopenia and the degenerative changes. The aim of this study is to investigate the intrinsic error for different techniques used in evaluation of local sagittal plane deformity caused by OVCF. Lateral X-rays of OVCF patients were randomly selected. Patient group was composed of 28 females and 7 males and the mean age was 62.7 (55-75) years. The kyphosis angle and the vertebral body height were analyzed to reveal the severity of sagittal plane deformity. Kyphotic deformity was measured by using four different techniques; and the vertebral body heights (VBH) were measured at three different points. The mean intra-observer agreement interval for kyphosis angle measurement techniques ranged from +/-7.1 to +/-9.3 degrees while it ranged from +/-4.5 to +/-6.5 mm for VBH measurement techniques. The mean interobserver agreement interval for kyphosis angle ranged from +/-8.2 to +/-11.1 degrees , while it was between +/-4.5 to +/-6.5 mm for vertebral body height measurement techniques. This study revealed that although the intra and interobserver agreement were similar for all techniques, they are still higher than expected. These high intervals for measurement errors should be taken into account when interpreting the results of correction in local sagittal plane deformities of OVCF patients after surgical procedures such as vertebral augmentation techniques.

Development and evaluation of thoracic kyphosis and lumbar lordosis during growth

PURPOSE

The aim of this study was to establish ranges of angular variation in lordotic and kyphotic curves in normal male and female children and adolescents.

METHODS

We developed a pantograph to measure dorsal curves. It consisted of a tripod-supported vertical strut to which an articulated bar was fixed and which had an arm that was able to follow the dorsal surface while moving up and down. This arm was positioned over the C7 spinous process and followed spinous processes to L5 at constant speed. A laser beam was used to ensure the proper positioning of the pantograph and the subject. The motion was recorded using software so that the dorsal outline was represented on a computer screen, and lordotic and kyphotic curves were automatically measured. Before performing the population study, the pantograph was validated in 20 normal subjects by comparing the pantograph measurements with lateral spine radiographs. There were no statistically significant differences in the measurements. There were 718 subjects with no race selection, of whom 350 were males and 368 females ranging in age from 5 to 20 years and presenting normal weight and height. Individuals with generalized ligament laxity, trunk asymmetry, muscle retraction, or any orthopedic anomaly were excluded from the study. Data were analyzed according to age and gender. Student's t tests and regression analysis were performed.

RESULTS

Kyphotic curves increased linearly from 25 degrees at 7 years of age to 38 degrees at 19 years of age (kyphotic angle = 25 degrees + 0.58 x age). Lordotic curves increased linearly from 22 degrees at 5 years of age to 32 degrees at 20 years of age (lordotic angle = 24 degrees + 0.51 x age). There were no differences between males and females.

CONCLUSIONS

The pantograph that was developed for this study was successfully used to establish the normal ranges and progression of thoracic kyphosis and lumbar lordosis in the studied population. Both curves increased linearly with age, with no differences between males and females.

Radiographic measures of thoracic kyphosis in osteoporosis: Cobb and vertebral centroid angles

OBJECTIVE

Several measures can quantify thoracic kyphosis from radiographs, yet their suitability for people with osteoporosis remains uncertain. The aim of this study was to examine the validity and reliability of the vertebral centroid and Cobb angles in people with osteoporosis.

DESIGN AND PATIENTS

Lateral radiographs of the thoracic spine were captured in 31 elderly women with osteoporosis. Thoracic kyphosis was measured globally (T1-T12) and regionally (T4-T9) using Cobb and vertebral centroid angles. Multisegmental curvature was also measured by fitting polynomial functions to the thoracic curvature profile. Canonical and Pearson correlations were used to examine correspondence; agreement between measures was examined with linear regression.

RESULTS

Moderate to high intra- and inter-rater reliability was achieved (SEM = 0.9-4.0 degrees ). Concurrent validity of the simple measures was established against multisegmental curvature (r = 0.88-0.98). Strong association was observed between the Cobb and centroid angles globally (r = 0.84) and regionally (r = 0.83). Correspondence between measures was moderate for the Cobb method r = 0.72), yet stronger for the centroid method (r = 0.80). The Cobb angle was 20% greater for regional measures due to the influence of endplate tilt.

CONCLUSIONS

Regional Cobb and centroid angles are valid and reliable measures of thoracic kyphosis in people with osteoporosis. However, the Cobb angle is biased by endplate tilt, suggesting that the centroid angle is more appropriate for this population.

The reliability and diagnostic value of radiographic criteria in sagittal spine deformities: comparison of the vertebral wedge ratio to the segmental cobb angle

STUDY DESIGN

A prospective, radiographic cohort study.

OBJECTIVES

This study assessed the radiographic reliability and diagnostic value of the vertebral wedge ratio (WR) to the more segmental Cobb angle (CA) regarding sagittal spine deformities.

SUMMARY OF BACKGROUND DATA

The use of the CA has been used to assist in the radiographic diagnosis of various sagittal spine deformities. However, the reliability and diagnostic aptitude of the CA remains speculative and may not be as receptive to individual variations of vertebral integrity in sagittal spine deformities.

METHODS

Sixty patients (age range, 8-21 years) who were diagnosed with Scheuermann's kyphosis (Group 1; n = 16), with postural roundback (Group 2; n = 23), or who were regarded normal (Group 3; n = 21) were radiographically evaluated to assess the reliability and diagnostic potential of the vertebral WR (apex of the curve and 2 adjacent vertebrae) and segmental CA. Radiographic assessment was conducted by 3 independent blinded observers on 3 separate occasions.

RESULTS

Very strong intraobserver (WR a = 0.85-0.99; CA a = 0.97-0.99) and interobserver (WR a = 0.79-0.89; CA a = 0.95) reliabilities were noted. A greater degree of WR reliability was noted in Group 1, whereas CA reliability remained consistent in all Groups. A statistically significant difference was found between all Groups in relation to vertebral WR and segmental CA (P < 0.05). Based on relative risk ratio analyses, an apex wedge ratio of < or = 0.80 and/or a segmental Cobb angle of > or = 20 degrees is highly and significantly associated with Scheuermann's kyphosis.

CONCLUSION

The segmental CA exhibited a higher degree of reliability than the vertebral WR. The apex vertebral WR exhibited the greatest amount of wedging in the Scheuermann's patients; whereas in the other groups it remained largely consistent with the adjacent vertebral WRs. An apex vertebral WR < or = 0.80 and/or a segmental CA of > or = 20 degrees are highly associated with the clinical diagnosis of Scheuermann's kyphosis. If the segmental CA cannot be ascertained, the apex vertebral WR is a relatively strong reliable alternative, primarily with regards to Scheuermann's kyphosis. In addition, the type of deformity may potentially dictate the ideal measuring method.

Angular measurement error due to different measuring devices

BACKGROUND

Angular measurements are commonly used in orthopaedic surgery. No study has addressed measurement variability due to the measurement device itself. It was the purpose of this study to assess measurement variability of articulated versus fixed devices.

METHODS

Three articulated and 4 fixed goniometers were randomly selected. Thirty-two different angles, ranging from a few degrees to nearly 180 degrees, were drawn with a standard soft-lead marking pencil. The angles were measured by 5 different observers with 7 different goniometers on 2 separate occasions separated by a minimum of 3 weeks. We wished to determine whether the variability of any goniometer was within a +/-1-degree range.

RESULTS

There were 1023 (91.3%) absolute differences of 1 degree or less and 97 (8.7%) of more than 1 degree. Intraobserver agreement was 92.0%; 96.9% for fixed and 84.0% for hinged goniometers. Interobserver agreement was of 90.7%; 96.2% for the fixed and 83.4% for the hinged goniometers. Intragoniometer agreement was 91.3%; 96.9% for fixed and 84.0% for hinged goniometers. Intergoniometer agreement was 87.0% with fixed goniometers demonstrating better agreement than hinged goniometers. The overall intraobserver and interobserver measurement variability was +/-2.33 and +/-2.26 degrees, respectively; the overall intragoniometer and intergoniometer measurement variability was +/-2.26 and +/-2.30 degrees, respectively. For fixed goniometers, the intergoniometer measurement variability is +/-2.0 degrees, for hinged goniometers, +/-2.9 degrees, and when using both fixed and hinged goniometers, +/-2.4 degrees. Thus, the fixed goniometers are the ideal type with overall better agreement and measurement variability.

CONCLUSION

Any one orthopaedic surgeon should use the same goniometer at all times, preferably a fixed type, so that measurement variability can be reduced by +/-2.0 degrees. If a physician uses a particular published measurement variability from the literature in which different goniometers were used, then the intraobserver measurement variability will be less than the published value by approximately +/-2 degrees. This is important when faced with the question of a change in an angular measurement being a true change or simply a reflection of measurement error.

Kyphoplasty and vertebroplasty: How good is the evidence?

The absence of Level I evidence undermines the credibility of all clinical studies pertaining to percutaneous vertebral augmentation (ie, kyphoplasty and vertebroplasty). The powerful desire to relieve suffering in the frail elderly cannot substitute for a rigorously designed randomized controlled trial comparing vertebral augmentation with continued nonoperative care. Though the level of available evidence is currently inadequate, its quality is improving.

Measurement error of lumbar total disc replacement range of motion

STUDY DESIGN

A retrospective review of lumbar total disc replacement (TDR) radiographs.

OBJECTIVE

To determine the error and variability in measuring TDR radiographic range of motion (ROM).

SUMMARY OF BACKGROUND DATA

Motion preservation is the driving force behind lumbar TDR technology. In the recent literature, sagittal radiographic TDR ROM as low as 2 degrees has been reported. In these studies, ROM was determined by using the Cobb method to measure TDR sagittal alignment angles in flexion-extension lateral radiographs. However, previous studies in the spinal deformity literature have shown that the Cobb method is very susceptible to measurement error.

METHODS

There were 5 observers, including 2 attending orthopedic spine surgeons, 1 spine fellow, 1 fifth-year resident, and 1 fourth-year resident, who measured the ROM of 50 ProDisc II (Synthes Spine Solutions, New York, NY) TDRs on standard flexion-extension lumbar spine radiograph sets. Repeated measurements were made on 2 occasions using the Cobb method. Measurement variability was calculated using 3 statistical methods.

RESULTS

The 3 statistical methods resulted in extremely similar values for TDR ROM observer variability. Overall, the intraobserver variability of TDR ROM measurement was +/-4.6 degrees, and interobserver variability was +/-5.2 degrees .

CONCLUSIONS

To be 95% certain that an implanted TDR prosthesis has any sagittal motion, a ROM of at least 4.6 degrees must be observed, which is the upper limit of intraobserver measurement variability for a TDR with a true ROM of 0 degrees. To be 95% certain that a change in TDR ROM has occurred between 2 measurements by the same observer, a change in ROM of at least 9.6 degrees must be observed (the entire range of +/-4.6 degrees intraobserver variability). ROM measurement variability should be considered when evaluating the success or failure of motion preservation in lumbar TDR.

Comparing a supine radiologic versus standing clinical measurement of kyphosis in older women: the Fracture Intervention Trial

STUDY DESIGN

A study of agreement between different measures of kyphosis, a clinical standing measure (Debrunner kyphometer; Protek AG, Bern, Switzerland) versus a supine radiologic measure (Cobb angle).

OBJECTIVES

To determine whether a supine radiologic measure of kyphosis in older women is a reasonable estimate of clinical kyphosis determined in the standing position, and to investigate a computerized assessment of the Cobb angle.

SUMMARY OF BACKGROUND DATA

Few studies have investigated kyphosis measurement agreement involving older adults.

METHODS

Using data from the Fracture Intervention Trial, we randomly selected 120 women, aged 55-80 years, who had a Debrunner kyphometer measure of kyphosis and supine lateral spine radiographs from which we measured the Cobb angle (either manually or by digitization). We calculated the intraclass correlation coefficient (ICC) from repeated measures analysis of variance to assess the agreement among the: (1) manual Cobb angle and Debrunner kyphometer, (2) digitized Cobb angle and Debrunner kyphometer, and (3) manual and digitized Cobb angle.

RESULTS

The mean of both the manual and digitized Cobb angle was 45 degrees (range 18 degrees-83 degrees), and the mean Debrunner kyphometer reading was 48 degrees (range 17 degrees-83 degrees). The ICC between either of the 2 measures of the Cobb angle and Debrunner measurement was 0.68, indicating reasonable agreement. The ICC between the manual and digitized Cobb angle was 0.99, indicating excellent agreement.

CONCLUSIONS

There is reasonable agreement between a supine radiologic and standing clinical measurement of kyphosis in older women.

Surgical Treatment of Congenital Kyphosis Associated With Progressive Spastic Paralysis in an Adult Patient-Case Report-

A 38-year-old man presented with untreated congenital kyphosis associated with progressive spastic gait. To prevent progression of the spastic paralysis, rigid correction of the severe spinal deformity arising from the congenital kyphosis was performed by one-stage posterior closing-wedge osteotomy, without occurrence of neurological complications. Progression of the paralysis has not been identified for 30 months after the operation and a slight improvement in gait was recognized. The current case is categorized as type I deformity of congenital kyphosis in the upper thoracic spine, which is normally treated surgically before the adolescent growth phase begins.

Measurement of fracture kyphosis with the Oxford Cobbometer: intra- and interobserver reliabilities and comparison with other techniques

STUDY DESIGN

Statistical analysis of 3 techniques for measuring thoracolumbar kyphosis secondary to fracture.

OBJECTIVES

To determine the reliability of using an Oxford Cobbometer and assess the most reliable measurement technique.

SUMMARY OF BACKGROUND DATA

The reproducibility of Cobb angles for the assessment of saggital plane deformity on spine radiographs has been shown to have significant variability in both intra- and interobserver error.

METHODS

Twenty-four lateral spine radiographs of patients with thoracic and lumbar vertebral fractures were measured on 2 separate occasions, in random order, by 4 blinded observers using the same Oxford Cobbometer and ruler.

RESULTS

Method 2, the angle from the inferior endplate of the vertebra above the fractured vertebra to the superior endplate of the vertebra below the fractured vertebra, had the greatest intraobserver and interobserver reliabilities (rho = 0.856-0.976 and rho = 0.95, respectively). The other 2 methods had lower reliabilities; however, all 3 methods were well above the statistically acceptable threshold of >0.8, and the intraobserver reliabilities with each observer was 99% overall. These reliabilities supersede results reported previously using the conventional Cobb technique. The absolute mean difference between readings and 95% limit of agreement also improves on previous data, 2 degrees and +/- 5.8 degrees , respectively.

CONCLUSIONS

Highest intraclass correlation coefficients were obtained using method 2. Using the Oxford Cobbometer to measure fracture kyphosis has higher reliability than the standard Cobb angle technique. It is easy and quick to use in a clinical setting.

Results of nonsurgical treatment of thoracic spinal tuberculosis in adults

BACKGROUND

The indications for surgery in spinal tuberculosis have been controversial, and more so recently, in the era of renewed understanding of the concept of multi-drug-resistant tuberculosis along with newer modalities of spinal instrumentation. Indications for surgery need to be redefined in this context.

PURPOSE

To assess the efficacy and results of nonsurgical treatment in thoracic spinal tuberculosis in adult patients, and redefine indications for surgery.

STUDY DESIGN

We present a retrospective analysis of 70 adults with thoracic spinal tuberculosis, with varying presentations, including abscesses and neurological deficits, seen at our spine clinic, in a period between August 1998 and August 2000, treated largely nonsurgically, with rewarding results.

METHODS

A retrospective study was made of 70 adult patients with thoracic spinal tuberculosis presenting at our spine clinic, between August 1998 and August 2000. All patients were subjected to medical management, unless there were specific indications for surgery, as per our protocol, wherein absolute indications of surgery in adults included advanced neurological deficit (less than Grade 3 by 5, by the 5-point grading system of the Medical Research Council), neurology worsening while on antituberculous chemotherapy, diagnosis in doubt on clinicoradiological evaluation and significant kyphosis (greater than 40 degrees) on presentation. Clinical and radiological assessment of results was made by an independent observer, at a mean follow up of 40 months.

RESULTS

Forty-four patients presented with abscesses, 21 of which were epidural. Seven had neurological signs of cord compression on clinical examination at presentation. Over 98% of our patients (69 of 70) were successfully treated conservatively, and none of these had any residual instability, radiculopathy or neurological compromise. Seventy-four percent had excellent to good results, with no mechanical residues of the disease, and 23% had residual kyphosis, which was clinically obvious, but biomechanically irrelevant.

CONCLUSIONS

We think that tuberculous spondylodiscitis in adults can be well managed conservatively in a vast majority of cases, and indications for surgery are few and specific.