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: A study of spondylolysis and spondylolisthesis in 142 children and adolescents is reported. In twelve of the seventy-nine patients followed for over a year the affected vertebra slipped further by 10 per cent or more. Increasing slip occurred mainly during the adolescent growth spurt, and was greater when spinal bifida or other vertebral anomalies were present. If at presentation the slip is less than 30 per cent then further slip beyond 30 per cent is unlikely. Decompression posteriorly is advised when signs of nerve pressure are present. Indications for spinal fusion are suggested; the intertransverse method of fusion was used in sixty-nine patients.Journal of Bone and Joint Surgery - British Volume 12/1977; 59-B(4):490-4. · 2.69 Impact Factor
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ABSTRACT: This paper presents a general statistical methodology for the analysis of multivariate categorical data arising from observer reliability studies. The procedure essentially involves the construction of functions of the observed proportions which are directed at the extent to which the observers agree among themselves and the construction of test statistics for hypotheses involving these functions. Tests for interobserver bias are presented in terms of first-order marginal homogeneity and measures of interobserver agreement are developed as generalized kappa-type statistics. These procedures are illustrated with a clinical diagnosis example from the epidemiological literature.Biometrics 04/1977; 33(1):159-74. · 1.41 Impact Factor
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ABSTRACT: A radiographic and morphologic study was conducted to investigate low-grade spondylolisthesis in cases with preexisting isthmic spondylolysis of L5. To distinguish radiographically between vertebral slips before and after skeletal maturity as determined by deformities of the sacral endplate. Very few reports have shown that spondylolisthesis with preexisting isthmic defects of L5 develops frequently in adulthood. The prognostic factors of the vertebral slip have remained unclear. It is hard to determine the onset time of low-grade spondylolisthesis. This study examined plain radiographs of 367 adult patients with pars defects of L5 (213 without slippage and 154 with Grade 1 or 2 spondylolisthesis) and 310 control subjects, ages 20 to 59 years at the first visit. The following parameters were measured and analyzed for each age decade: the sacral table index (anteroposterior width of the sacral endplate expressed as a percentage of the anteroposterior diameter of the upper L5 endplate), the sacral table angle (formed by the sacral endplate with the posterior wall of S1), the relative thickness of the L5 transverse process, and the iliac crest height. The prevalence of patients with slippage who met deformity criteria (sacral table index > 102% [the mean plus 2 standard deviations of the controls] and sacral table angle </=97 degrees [the mean of the controls]) remained almost one fourth during all decades. On the contrary, the prevalence of patients with slippage who met normal-shape criteria (sacral table index </=102% and sacral table angle >/=89 degrees [mean minus 2 standard deviations of the controls]) was 0% in the third decade, but increased remarkably in the fifth and sixth decades. Of the 213 patients without slippage, 8 patients in whom new slippage developed during long-term follow-up evaluation all had a normally-shaped sacral table. The prevalence of patients without slippage decreased gradually with age, and elderly patients had relatively broader transverse processes and a higher iliac crest line. The authors considered that the slips with and those without deformities of the sacral table had developed in adolescence and adulthood, respectively. Using new radiographic parameters that indicate widening and tilting of the sacral table, low-grade isthmic spondylolis thesis can be categorized into "adolescent and adult vertebral slips."Spine 04/2002; 27(8):831-8. · 2.16 Impact Factor