Assessment of sacral doming in lumbosacral spondylolisthesis.
ABSTRACT Quantitative versus subjective evaluation of sacral doming in lumbosacral spondylolisthesis.
To evaluate the relevance of the Spinal Deformity Study Group (SDSG) index in the assessment of sacral doming and to propose a quantitative criterion to differentiate between significant and nonsignificant doming.
There is no consensus on the optimal technique to assess sacral doming, although it is an important feature in spondylolisthesis.
Five spinal surgeons subjectively assessed the sacral endplate of 100 subjects (34 high-grade spondylolisthesis, 50 low-grade spondylolisthesis, 16 controls) from lateral radiographs. Subjects were classified by each surgeon as having significant or nonsignificant sacral doming. An independent observer quantitatively evaluated sacral doming for all subjects using the SDSG index. A criterion to differentiate significant from nonsignificant sacral doming was sought, based on the comparison between the subjective assessment of surgeons and the quantitative evaluation by the independent observer. Intrarater and interrater reliability of the SDSG index was evaluated using intraclass correlation coefficient (ICC).
Intrarater and interrater ICCs for the SDSG index were excellent at 0.91 and 0.88, respectively. Sacral doming evaluated with the SDSG index was 11.6% +/- 5.0% (range, 1.5%-18.9%), 16.4% +/- 6.3% (range, 3.7%-35.6%), and 27.9% +/- 10.9% (range, 5.7%-56.9%) for controls, low-grade, and high-grade cases, respectively. Overall intersurgeon agreement on the significance of sacral doming was substantial at 88% (kappa = 0.72). With a threshold value of 25% for the SDSG index, 93% of concordance was found between the quantitative evaluation using the SDSG index and the multisurgeons subjective assessment.
This study confirms the relevance of the SDSG index to assess sacral doming in lumbosacral spondylolisthesis. The authors propose a criterion of 25% to differentiate significant from nonsignificant sacral doming using the SDSG index. Such a criterion will allow more accurate assessment of sacral remodeling, especially for borderline cases, and facilitate comparisons between studies.
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ABSTRACT: Although recognized as an important aspect in the management of spondylolisthesis, there is no consensus on the most reliable and optimal measure of lumbosacral kyphosis (LSK). Using a custom computer software, four raters evaluated 60 standing lateral radiographs of the lumbosacral spine during two sessions at a 1-week interval. The sample size consisted of 20 normal, 20 low and 20 high grade spondylolisthetic subjects. Six parameters were included for analysis: Boxall's slip angle, Dubousset's lumbosacral angle (LSA), the Spinal Deformity Study Group's (SDSG) LSA, dysplastic SDSG LSA, sagittal rotation (SR), kyphotic Cobb angle (k-Cobb). Intra- and inter-rater reliability for all parameters was assessed using intra-class correlation coefficients (ICC). Correlations between parameters and slip percentage were evaluated with Pearson coefficients. The intra-rater ICC's for all the parameters ranged between 0.81 and 0.97 and the inter-rater ICC's were between 0.74 and 0.98. All parameters except sagittal rotation showed a medium to large correlation with slip percentage. Dubousset's LSA and the k-Cobb showed the largest correlations (r= -0.78 and r= -0.50, respectively). SR was associated with the weakest correlation (r= -0.10). All other parameters had medium correlations with percent slip (r= 0.31-0.43). All measurement techniques provided excellent inter- and intra-rater reliability. Dubousset's LSA showed the strongest correlation with slip grade. This parameter can be used in the clinical setting with PACS software capabilities to assess LSK. A computer-assisted technique is recommended in order to increase the reliability of the measurement of LSK in spondylolisthesis.European Spine Journal 12/2008; 18(2):212-7. · 2.47 Impact Factor
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ABSTRACT: STUDY DESIGN: Retrospective study of the importance of sacral and sacro-pelvic morphology in developmental L5-S1 spondylolisthesis. OBJECTIVES: To determine and compare the importance of sacral and sacro-pelvic morphology in developmental L5-S1 spondylolisthesis. Recent studies have shown abnormalities in sacral and sacro-pelvic morphology in spondylolisthesis. However, it is still unclear if sacral and sacro-pelvic morphology are correlated and if they are equally important in the progression of spondylolisthesis. METHODS: Lateral radiographs of 120 controls and 131 subjects with developmental L5-S1 spondylolisthesis were analyzed. Sacral table angle (STA) and pelvic incidence (PI) were compared using Student t tests. The relationship between STA and PI was assessed separately in the control and spondylolisthesis groups using Pearson's coefficients. The proportion of subjects with high PI but average STA was compared to the proportion of subjects with low STA but average PI using χ (2) tests. RESULTS: STA was significantly lower and PI was significantly higher in the spondylolisthesis group. STA was statistically related to PI in both control (r = -0.43) and spondylolisthesis (r = -0.57) groups. In the spondylolisthesis group, STA (r = -0.45) and PI (r = 0.35) were significantly related to slip percentage. STA remained statistically related to slip when controlling for PI. A significantly greater proportion of subjects in the spondylolisthesis group had average STA and high PI, rather than average PI and low STA. CONCLUSION: The significant relationship between PI and STA validates that geometrically sacral morphology depends on sacro-pelvic morphology. This study failed to demonstrate a clear predominant role of either STA or PI in the presence of spondylolisthesis.European Spine Journal 05/2013; · 2.47 Impact Factor
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ABSTRACT: Purpose of the study The pelvic incidence (PI) is an anatomic parameter independent of the spatial orientation of the pelvis. However, measuring the PI remains a technically difficult task. PI is determined from radiographic construction which has several consequences. Imperfect radiographic incidence may compromise optimal conditions for measurement. Anatomic remodeling of the sacral plate can also have an impact on rigorous measurement of the PI. Several solutions have been proposed in the literature in order to obtain equivalent measurements. The proposed methods (Duval-Beaupere, Vialle) appear logical, but remain to be validated. The purpose of this study was to determine whether the angle measured on the plain x-ray is affected by the radiographic quality of the image and to determine whether the “variant pelvic incidence” (VPI) using a reference constituted by the posterior aspect of the sacrum, can be accepted as a valid equivalent to PI in the event of anatomic remodeling. Material and methods This was a prospective study conducted in 50 patients. The PI and the VPI were measured on 3D computed tomography reconstructions which allowed three series of measurements: in a strictly lateral view, in a view with the position of the femoral heads shifted in the horizontal plane, and a view with the position of the femoral heads shifted in the vertical plane. Statistical analysis was applied to compare the three series of measures in order to search for a significant difference for the two angles under consideration (PI and VPI) dependent on the position of the pelvis. Results There was no significant difference in PI as a function of the position of the femoral heads: the coefficients of variation were all greater than 0.98 (p < 0.01). For VPI, there was a significant difference between the theoretical ideal position and the horizontal shift of the femoral heads (p < 0.05). Average measurements of PI and VPI were statistically different for each individual (p < 0.05), with no identifiable relationship between the two values (PI and VPI). Discusssion Pelvic incidence is a reliable measure, even if the quality of the x-ray is not perfect. Conversely, the variant, using the posterior aspect of the sacrum, is highly dependent on pelvic orientation, with significant differences with position. We were unable to establish a relation between PI and VPI. In practice, it would be licit to consider that the straight line between the two femoral heads indicates the center of the femoral heads. On the contrary, it would not be wise to consider the posterior aspect of the sacrum as a reliable reference.Revue De Chirurgie Orthopedique Et Reparatrice De L Appareil Moteur - REV CHIR ORTHOP REPARAT APP. 01/2008; 94(4):321-326.