Pelvic Lordosis Research Articles

Correlation of Sacropelvic Geometry With Disc Degeneration in Spondylolytic Cadaver Specimens

An anatomic study of sacral inclination, pelvic incidence, pelvic lordosis, and disc degeneration in cadaveric lumbar spines. To evaluate the relationship between sacropelvic parameters and disc degeneration in subjects with bilateral spondylolysis at L5. L5-S1 disc degeneration is greater in patients with spondylolytic defects (L5-S1) than with an intact pars interarticularis secondary to the instability caused by spondylolysis. Sacral inclination, pelvic incidence, and pelvic lordosis affect sagittal balance and axial forces on the L5-S1 disc. An observational study was performed on 120 cadaveric specimens with spondylolysis (L5-S1) identified of 3100 total cadaveric specimens. Nine specimens were excluded because of incomplete or degraded skeletal elements; 10 were excluded for having unilateral defects only. The specimens were evaluated for sacral inclination, pelvic incidence, and pelvic lordosis. Disc degeneration and facet arthrosis at L4-L5 and L5-S1 were measured by the classification of Eubanks et al. Linear regression analyses were then used to determine the relationship between sacropelvic parameters and degeneration at the L5-S1 segment, correcting for confounding factors such as age, sex, and race. Linear regression demonstrated a significant association between sacral inclination and disc degeneration at L5-S1 (P = 0.018). Specimens were then divided into two groups, those in the highest quarter of pelvic incidence, and the remainder. Spearman rank correlation demonstrated a significant association between disc degeneration at L5-S1 and the highest quarter of pelvic incidence (P = 0.017). Increasing pelvic lordosis was also associated with an increase in facet arthrosis at L4-L5 (P = 0.006). The findings of this study show a relationship between the sacropelvic geometry and the degree of L5-S1 disc degeneration as well as L4-L5 facet degeneration in spondylolytic specimens. This relationship may prove useful in predicting the course of disc degeneration in patients with spondylolysis.

Clasped position for measurement of sagittal spinal alignment

Lateral whole-spine radiography is a useful tool in the management of spinal deformity, but the most appropriate arm position during radiography has yet to be determined. In this prospective study, we evaluated 26 adult volunteers and 22 patients with lumbar spinal canal stenosis. Lateral whole-spine radiographs were acquired in the most stable and relaxed position while the subjects were standing with their arms extended and their hand gently clasped in front of the trunk (clasped position). The following parameters were measured: sagittal vertical axis (SVA), lumbar lordotic angle (LLA), pelvic angle (PA), pelvic lordosis angle (PRS1), pelvic tilt (PT), and pelvic incidence (PI). The reliability of measurements was assessed by interclass correlation coefficients. The SVA was slightly positive in volunteers. LLA, PA, PRS1, PT, and PI were compatible with standard normal values. The results showed "almost perfect agreement" with regard to intra- and interobserver reliability. The clasped position can be used effectively and reliably for measurement of sagittal spinal alignment for the lumbar region in adults.

Influence of the sagittal anatomy of the pelvis on the intercrestal line position

The line joining the two iliac crests is classically regarded as the anatomical landmark determining the inter-vertebral space L4-L5 for the spinal punctures. Its variability has been reported but never related to predictive clinical anatomic factors identifying patients groups in which there is increased risk of miscalculation of the spinal level. Two sagittal pelvic anatomical angles, called 'pelvic incidence' and 'pelvic lordosis' were measured on lateral X-rays of the pelvis of 132 normal individuals and 49 spondylolysis patients. The values were compared with the sagittal projection of the intercrestal line on the disco-vertebral lumbar structures. A strict relation was observed between this projection of the intercrestal line and the sagittal pelvic anatomical angles. The greater the pelvic incidence, the higher the intercrestal line was projected, all the more in patients with spondylolysis with a listhesis or a disc narrowing. The relation between the pelvic sagittal angles and the intercrestal line projection explains the variability described for this anatomical landmark. It implies precautions minimizing neurological risk in the case of a puncture carried out more cranially than expected, particularly for high values of pelvic incidence occurring in spinal pathologies such as spondylolysis, in the elderly or in the obese patients. In these cases, we recommend the use of spinal imaging during the procedure to assist selection of the desired insertion level.

The femoro-sacral posterior angle: an anatomical sagittal pelvic parameter usable with dome-shaped sacrum

The sagittal pelvic morphology modulates the individual alignment of the spine. Anatomical angular parameters were described as follows: the "Pelvic Incidence" (PI) and the Jackson's angle "Pelvic Lordosis" (PR-S1). Significant chains of relationships were expressed connecting these angles with pelvic and spinal positional parameters. This allows an individual assessment of the harmony of the sagittal spinal balance. But in case of spondylolysis with high-grade listhesis, the upper plate of the sacrum shows a dome-shaped deformity. The previous anatomical parameters are therefore imprecise. Indeed, the anterior part of the sacrum being inaccurate, an exact assessment of these angles becomes impossible. Therefore, we propose a new angular parameter named "Femoro-Sacral Posterior Angle" (FSPA): the angle between the posterior wall of the first sacral vertebra, always well definite, and the line connecting the posterior part of the sacral plate to the femoral axis. The validation of this parameter was performed and compared with the classical published parameters. It showed good inter-observer reliability, even with dome-shaped sacral plate. In spite of lower correlation with the positional parameters than those observed with PI or PR-S1, the FSPA appeared to be reliable and precise for an exact evaluation of the sagittal spino-pelvic balance is case of spondylo-listhesis with dome-shaped sacral endplate.

Radiologic Measurement of Pelvic Sagittal Incidence and Lordosis in Young Korean Women

Purpose: To determine the normative data for the pelvic morphology parameters in the young Korean female population. Materials and Methods: Young Korean female patients in 20s and 30s who had visited the outpatient clinic for a first attack acute sprain underwent a telephone interview at a minimum of 1 year after their last hospital visit. Those who had recovered completely and had no back-related complaints were selected for the pelvic lordosis angle (PRS1) and pelvic angle of incidence (AOI) measurements (n=40 each age group). Results: There was no age difference in both parameters. The PRS1 in the young female population was (range: 13.6-) and the AOI was (range: 30.5-), which shows a close correlation between the two parameters (correlation coefficient, r=-0.965). The linear regression equation obtained is as follow; Equation I: PRS1=79.909-0.850AOI, Equation II: AOI=90.902-1.096PRS1 (linear regression analysis, p=0.000, =0.931). Conclusion: The data obtained from the study may be used for future studies related to the sagittal spinopelvic balance.

Pelvic lordosis and pelvic incidence: the relationship of pelvic parameters to sagittal spinal profile

Pelvic lordosis and pelvic incidence: the relationship of pelvic parameters to sagittal spinal profile

Pelvic lordosis and alignment in spondylolisthesis.

Pelvic morphology and lumbopelvic lordosis were measured on standing radiographs of 75 patients with greater than 10% L5-S1 spondylolytic spondylolisthesis. The findings were compared with those of 75 volunteers to determine significant differences between the two groups. Etiology of isthmic (lytic) spondylolisthesis remains uncertain. Causation appears to be multifactorial. The relationship between pelvic morphology and spondylolisthesis deserves additional study. Both groups had a standing lateral radiograph of the thoracolumbar spine and pelvis taken that included both hips. Three radiographic angles for pelvic morphology (pelvisacral, pelvic incidence, and pelvic lordosis) were measured by two observers. Each offered similar reliability. Measurement of the pelvic lordosis angle by the pelvic radius technique required fewer steps. It also allowed calculation of the combined angles comprising both the pelvic morphology component for lordosis (the constant pelvic lordosis angle) and the lordosis in the lumbar spine (the variable lumbar lordosis from T12-S1) that should complement the fixed pelvic lordosis (the complementary lumbopelvic lordosis). Mean values and statistical correlations were then computed for each group and compared. The mean slippage for patients was 30% (range, 11-85%), with 34 patients (45%) having Grade I slips, 32 (43%) having Grade II slips, and nine (12%) having Grade III and IV slips. The mean measurements between patients and volunteers were significantly different (P < 0.01) for lumbar lordosis, pelvic lordosis, and lumbopelvic lordosis. Subgroups of patients with increasingly larger slips (Grade I-III) had significantly smaller mean angles for pelvic lordosis. The pelvic and lumbopelvic parameters studied were different in patients compared with controls. The contribution of the pelvis to lordosis was significantly smaller in the subgroups of patients with increasingly larger grades of spondylolisthesis. Pelvic morphology may play a role in the development of spondylolisthesis. Measurement of the combined lumbar and pelvic (lumbopelvic) lordosis on standing radiographs is important.