Spinopelvic Relationship Research Articles

Is There an Association With Spino-Pelvic Relationships and Clinical Outcome of Type A Thoracic and Lumbar Fractures Treated Non-Surgically?

The objective was to evaluate if there is an association of the spino-pelvic relationships and the global spinal alignment with the outcome of AO type A injuries treated nonsurgically. This is a retrospective case series. Patients treated nonsurgically for AOSpine type A fractures (T1-L5) with at least 1 year follow-up identified. A standing antero-posterior and lateral 36-inch radiographs and measures of spino-pelvic relationships and sagittal alignment were obtained, as well as clinical assessment using the visual analog scale, the Short-Form 36 (SF-36) questionnaire, the Oswestry Disability Index (ODI), and labor status. Twenty-two patients with 33 fractures were included (L1 was the most injured level with 18.2%). There were 17 men (77.2%) and the mean age was 47.1 years. Follow-up ranged from 12 to 60 months (mean of 27.8 months). There were 22 type A1 (66.7%), 3 type A2 (9%), 6 type A3 (18%), and 2 type A4 (6%) fractures. The ODI ranged from 4% to 58%, with a mean of 24.4%. The SF-36 physical health score ranged from 23 to 82.25 (mean 49.59), and the mental health score ranged from 14.75 to 94.25 (mean 63.28). No association was identified between the spino-pelvic measurements, global alignment, and patient-reported outcomes. Type A fractures had a clinically relevant amount of long-term disability even when surgical treatment is not required. Spino-pelvic relationships and final global spinal alignment did not associate with outcome measurements.

Impact of sagittal balance parameters on life quality in elderly and senile patients after surgery for degenerative lumbar spine stenosis

As the life span and proportion of people over 65 years increase, the incidence of degenerative lumbar spine stenosis grows proportionally. Various parameters of the spinopelvic relationships are used to predict surgical treatment outcomes in patients with degenerative spine diseases. There are no unified protocols for evaluation, in terms of the sagittal balance, of surgical treatment outcomes in elderly patients. To study the impact of sagittal balance parameters on the life quality of elderly and senile patients after surgery for degenerative stenosis of the lumbar spine. The study included 109 patients. Decompression was performed in the first group of 53 patients. Decompression and stabilization were performed in the second group of 27 patients. In the third group of 29 patients, XLIF indirect decompression, scoliosis correction, reconstruction of disturbed spinopelvic relationships, and stabilization were carried out. We evaluated the following sagittal balance parameters: pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), and PI minus LL (PI-LL). The quality of life indicators were assessed using VAS, ODI, and SF36 scores. In the first group, there were not statistically significant differences for PT≤20° and PT>20°. A statistically significant change in the PI-LL parameter (p=0.0263) was in the first group. A decrease in PI-LL was accompanied by regression of pain (p<10-4). In the second group, comparison of the quality of life indicators revealed no statistically significant differences between PT≤20° and PT>20° as well as PI-LL≤10° and PI-LL>10 in the postoperative period. In the third group, postoperative improvement in PT (p=0.0002) and PI-LL (p=0.0008) parameters was accompanied by a decrease in pain in the legs (p=0.0002) and lumbar spine (p=0.0001). Improvement in the quality of life indicators in 48.6% of cases was achieved by decompression only; the sagittal balance parameters had no significant impact on quality of life. In 24.8% of cases, improvement in the quality of life indicators was achieved by decompression and stabilization because the dominant clinical neurological syndrome was instability. Reduced quality of life in 26.6% of patients was caused by disturbed spinopelvic relationships. Application of the XLIF technique in these patients provides statistically significant restoration of the sagittal balance parameters, PT and PI-LL, which improves quality of life.

Decreasing pelvic incidence is associated with greater risk of cam morphology.

ObjectivesThe spinopelvic relationship (including pelvic incidence) has been shown to influence pelvic orientation, but its potential association with femoroacetabular impingement has not been thoroughly explored. The purpose of this study was to prove the hypothesis that decreasing pelvic incidence is associated with increased risk of cam morphology.MethodsTwo matching cohorts were created from a collection of cadaveric specimens with known pelvic incidences: 50 subjects with the highest pelvic incidence (all subjects > 60°) and 50 subjects with the lowest pelvic incidence (all subjects < 35°). Femoral version, acetabular version, and alpha angles were directly measured from each specimen bilaterally. Cam morphology was defined as alpha angle > 55°. Differences between the two cohorts were analysed with a Student’s t-test and the difference in incidence of cam morphology was assessed using a chi-squared test. The significance level for all tests was set at p < 0.05.ResultsCam morphology was identified in 47/100 (47%) femurs in the cohort with pelvic incidence < 35° and in only 25/100 (25%) femurs in the cohort with pelvic incidence > 60° (p = 0.002). The mean alpha angle was also greater in the cohort with pelvic incidence < 35° (mean 53.7°, sd 10.7° versus mean 49.7°, sd 10.6°; p = 0.008).ConclusionsDecreased pelvic incidence is associated with development of cam morphology. We propose a novel theory wherein subjects with decreased pelvic incidence compensate during gait (to maintain optimal sagittal balance) through anterior pelvic tilt, creating artificial anterior acetabular overcoverage and recurrent impingement that increases risk for cam morphology.Cite this article: W. Z. Morris, C. A. Fowers, R. T. Yuh, J. J. Gebhart, M. J. Salata, R. W. Liu. Decreasing pelvic incidence is associated with greater risk of cam morphology. Bone Joint Res 2016;5:387–392. DOI: 10.1302/2046-3758.59.BJR-2016-0028.R1.

Is There a Gender-Specific Full Body Sagittal Profile for Different Spinopelvic Relationships? A Study on Propensity-Matched Cohorts

DesignRetrospective review. ObjectiveTo evaluate gender-related differences in compensatory recruitment to progressive sagittal malalignment. Summary of Background DataRecent research has elucidated compensatory mechanisms recruited in response to sagittal malalignment, but gender-specific differences in compensatory recruitment patterns is unknown. MethodsSingle-center study of patients with full body x-rays. A female group was propensity matched by age, body mass index (BMI), and pelvic incidence (PI) to a male group. Patients were then stratified into five groups of progressive PI–lumbar lordosis (LL) mismatch (<0°, 0°–10°, 10°–20°, 20°–30°, >30°). Differences between PI-LL groups were assessed with analysis of variance, and between genders by unpaired t test. Knee flexion to pelvic tilt (PT) ratio was computed and compared between genders. Multivariate regression to develop predictive models for PT was performed for each gender, first with spinopelvic parameters and subsequently with inclusion of lower limb parameters. ResultsA total of 942 patient visits were included: 471 females (mean age 54 years, BMI 27, PI 51°) and 471 males (mean age 52 years, BMI 27, PI 51°). At the lowest level of malalignment, females had greater PT and less knee flexion. With progressive malalignment, females continued to exhibit a pattern of greater pelvic retroversion and less knee flexion compared to males. Hip extension was higher in females with progressive PI-LL mismatch groups. Both genders progressively recruited knee flexion and pelvic retroversion with increased PI-LL mismatch, except that at the higher PI-LL mismatch groups, only males continued to recruit knee flexion (all p < .05). Inclusion of lower limbs in the regression for PT markedly improved correlation coefficients for females but not for males. ConclusionsWith progressive sagittal malalignment, men recruit more knee flexion and women recruit more pelvic tilt and hip extension. Knee flexion is a possible mechanism to gain pelvic tilt for females whereas for males, knee flexion is an independent compensatory mechanism.

Sagittal Balance in Adolescent Idiopathic Scoliosis: A Radiographic Study of Spinopelvic Compensation After Selective Posterior Fusion of Thoracolumbar/Lumbar (Lenke 5C) Curves.

The relationship between spinal sagittal alignment and pelvic parameters is well known in adolescent idiopathic scoliosis. However, few studies have reported the sagittal spinopelvic relationship after selective posterior fusion of thoracolumbar/lumbar (TL/L) curves.We evaluated the relationship between spinal sagittal alignment and the pelvis, and analyzed how the pelvic sagittal state is adjusted in Lenke type 5C patients.We conducted a retrospective study of 36 patients with Lenke type 5C curves who received selective posterior TL/L curve fusion. Coronal and spinopelvic sagittal parameters were pre and postoperatively compared. Pearson coefficients were used to analyze the correlation between all spinopelvic sagittal parameters before and after surgery. We also evaluated 3 pelvic morphologies (anteverted, normal, and retroverted) before and after surgery.Preoperatively, the mean pelvic incidence was 46.0°, with a pelvic tilt and sacral slope (SS) of 8.2° and 37.8°, respectively, and 25% (9/36) of patients had an anteverted pelvis, whereas the other 75% had a normal pelvis. Postoperatively, 42% (15/36) of patients had a retroverted pelvis, 53% (19/36) had a normal pelvis, and 2 patients had an anteverted pelvis. Logistic regression analyses yielded 2 factors that were significantly associated with the risk for a postoperative unrecovered anteverted pelvis, including increased lumbar lordosis (LL) (odds ratio [OR] 4.8, P = 0.029) and increased SS (OR 5.6, P = 0.018). Four factors were significantly associated with the risk of a postoperative newly anteverted pelvis, including LL at the final follow-up (OR 6.9, P = 0.009), increased LL (OR 8.9, P = 0.003), LL below fusion (OR 9.4, P = 0.002), and increased SS (OR 11.5, P = 0.001).The pelvic state may be adjusted after selective posterior TL/L curve fusion in Lenke 5C adolescent idiopathic scoliosis patients. It is difficult to improve an anteverted pelvis in patients who have an LL that is increased by more than 11.6° or an SS that is increased by more than 4.7° after surgery. The anteverted pelvic state will generally occur with posterior correction surgery for patients with an LL that is greater than 63.7°, or an LL or SS that is respectively increased by more than 17.6° or 9.0° postoperatively.

Successful Correction of Sagittal Imbalance can be Calculated on the Basis of Pelvic Incidence and Age

Introduction Sagittal imbalance is an independent predictor of outcome in adult degenerative spinal deformity. Restoration of sagittal spinopelvic parameters correlates with a better postoperative outcome. Several methods of preoperative calculation for sagittal correction have been proposed, most of them geometrical. A nongeometrical method, based on data of spinopelvic relationships in normal subjects, that uses the patient's pelvic incidence and age to calculate target lumbar lordosis and thoracic kyphosis is proposed. The goal of this study is to describe and validate this nongeometrical method in terms of sensitivity and specificity to predict satisfactory spinopelvic alignment. Materials and Methods A retrospective cohort study of patients operated for sagittal imbalance with pedicle subtraction osteotomies (PSO). Two calculation algorithms (method a: LL = −[32.56 + PI × 0.54], method b: LL = −[PI + 10 degrees]); in both TK = PI/r (see text for definitions) obtain theoretical lumbar lordosis (LL) and thoracic kyphosis (TK) solely based on pelvic incidence and age, for surgical planning. The sample is categorized according to two parameters: planning goals (LL and TK) achieved or not and satisfactory alignment (SVA &lt; 50 mm and PT &lt; 20 degrees) achieved or not. Two × two tables are built and odds ratio, sensitivity and specificity and PPV/NPV are calculated for each planning method. Different levels of tolerance for undercorrection are analyzed to refine the use of the method. Results Of the 50 patients included in the study, 23 presented satisfactory alignment postoperatively. With a tolerance of hypocorrection of 10 degrees (LL) and 30 degrees (TK), correction target was achieved in 23 patients according to method a (S = 0.89, Sp = 0.87%, OR = 53.33 [95% CI: 9.677–293.931]; p &lt; 0.001), 23 patients according to method b (S = 0.93, Sp = 0.91, OR = 131.25 [95% CI:17–1013]; p &lt; 0.001). The best prediction of satisfactory alignment was obtained with method b and tolerance 0 degrees (LL) and 10 degrees (TK). All patients with complete correction of LL (both methods) achieved good alignment. Overall, 22 of the 24 (91%) patients with less than 10 degrees of undercorrection of LL (method b) achieved good alignment. Conclusion Calculation of the target lordosis based only in the value of PI and age is a reliable method that can predict good outcomes in terms of alignment. The rule LL = −(PI + 10 degrees) is an easy to calculate and very effective method of planning for lumbar lordosis and good alignment can be expected with high confidence when the final lordosis is within 10 degree of undercorrection. Including TK in surgical planning can improve the results in terms of restoration of the less known “spinopelvic balance” parameter.