A Retrospective Study of the Effect of Spinopelvic Parameters on Fatty Infiltration in Paraspinal Muscles in Patients With Lumbar Spondylolisthesis

OBJECTIVE

The effect on fat infiltration (FI) of paraspinal muscles in degenerative lumbar spinal diseases has been demonstrated except for spinopelvic parameters. The present study is to identify the effect of spinopelvic parameters on FI of paraspinal muscle (PSM) and psoas major muscle (PMM) in patients with degenerative lumbar spondylolisthesis.

METHODS

A single-center, retrospective cross-sectional study of 160 patients with degenerative lumbar spondylolisthesis (DLS) and lumbar stenosis (LSS) who had lateral full-spine x-ray and lumbar spine magnetic resonance imaging was conducted. PSM and PMM FIs were defined as the ratio of fat to its muscle cross-sectional area. The FIs were compared among patients with different pelvic tilt (PT) and pelvic incidence (PI), respectively.

RESULTS

The PSM FI correlated significantly with pelvic parameters in DLS patients, but not in LSS patients. The PSM FI in pelvic retroversion (PT > 25°) was 0.54 ± 0.13, which was significantly higher in DLS patients than in normal pelvis (0.41 ± 0.14) and pelvic anteversion (PT < 5°) (0.34 ± 0.12). The PSM FI of DLS patients with large PI ( > 60°) was 0.50 ± 0.13, which was higher than those with small ( < 45°) and normal PI (0.37 ± 0.11 and 0.36 ± 0.13). However, the PSM FI of LSS patients didn't change significantly with PT or PI. Moreover, the PMM FI was about 0.10-0.15, which was significantly lower than the PSM FI, and changed with PT and PI in a similar way of PSM FI with much less in magnitude.

CONCLUSION

FI of the PSMs increased with greater pelvic retroversion or larger pelvic incidence in DLS patients, but not in LSS patients.

Femoral neck version in the spinopelvic and lower limb 3D alignment: a full-body EOS® study in 400 healthy subjects

BACKGROUND

The goal of this study was to better understand the variation of femoral neck version according to spinopelvic and lower limb 3D alignment using biplanar X-rays in standing position.

METHODS

This multicentric study retrospectively included healthy subjects from previous studies who had free-standing position biplanar radiographs. Subjects were excluded if they presented spinal or any musculo-skeletal deformity, and reported pain in the spine, hip or knee. Age, sex, and the following 3D-reconstructed parameters were collected: spinal curvatures, pelvic parameters, sagittal vertical axis (SVA), T1 pelvic angle (TPA), spino-sacral angle (SSA), femoral torsion angle (FTA), sacro-femoral angle (SFA), knee flexion angle (KA), ankle angle (AA), pelvic shift (PS) and ankle distance. Femoral neck version angle (FVA) was calculated between horizontal plane projection of the bi-coxo-femoral axis and the line passing through the femoral neck barycenter and femoral head center. Analysis according to age subsets was performed.

RESULTS

A total of 400 subjects were included (219 females); mean age was 29 ± 18 years (range: 4-83). Subjects with high pelvic tilt values presented significantly higher FVA than average and low-PT individuals, respectively, 7.8 ± 7.1°, 2 ± 9° and 2.1 ± 9.5° (p < 0.001). These subjects also presented lower lumbar lordosis values and higher acetabulum anteversion in the horizontal plane than the two other groups. SVA correlation with FVA was weaker (r = 0.1, p = 0.03) than SSA and TPA (r = - 0.3 and r = 0.3, respectively, p < 0.001). A strong correlation was found with femoral torsion (r = 0.5, p < 0.001). SFA (r = - 0.3, p < 0.001), pelvic shift (r = 0.2, p < 0.001) and ankle distance (r = 0.3, p < 0.001) were also significantly correlated. Multivariate analysis confirmed significant association of age, pelvic tilt, lumbar lordosis, pelvic shift, ankle distance and femoral torsion with FVA.

CONCLUSION

Patients with lower lumbar lordosis present pelvic retroversion which induces a higher femoral neck version. This finding may help positioning implants in total hip replacement procedures. Higher pelvic shift, age, male gender and increased femoral torsion were also correlated with higher FVA.

LEVEL OF EVIDENCE

II (Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding).

[Lumbo-pelvino-acetabular alignment-basics and clinical consequences]

The spinal shape and the pelvic ante-/retroversion of an individual are determined by its innate, genetically fixed lumbosacral angulation. This can be measured with little effort in the lateral standing radiograph of the patient. In spinal surgery, there are a lot of original papers on the topic. In hip surgery, however, the individual pelvic version and its consequences for the acetabular orientation have not received the same attention so far.This review focuses on previous data on the relationship between lumbosacral angulation and pelvic ante-/retroversion. Four anatomically definable pelvic types can be distinguished; three of those have to be considered as facultatively pathogenetic. Clinical consequences arise for the clinical pictures of spondylolisthesis, non-specific lower back pain, acetabular retroversion and developmental dysplasia of the hip, as well as for acetabular cup positioning in total hip arthroplasty.

Compensatory mechanisms recruited against proximal junctional kyphosis by patients instrumented from the thoracolumbar junction to the iliac

PURPOSE

The compensatory mechanisms recruited by un-instrumented patients against sagittal imbalance are well documented. However, there is a lack of information regarding instrumented patients.

MATERIAL AND METHODS

We performed a retrospective analysis of data collected prospectively in a multicenter adult spinal deformity database. We included patients suffering PJK/PJF after (T8-L2) to iliac instrumentation with minimum two-year follow-up. We measured quantitative sagittal spinopelvic and qualitative sagittal distribution parameters in the immediate postoperative period (6w) and at the time of PJK/PJF appearance. We analyzed how these parameters changed comparing these two time points with univariate and multivariate logistic regression analyses.

RESULTS

A total of 69 patients were included. Two different patterns at PJK/PJF were found: 36 patients activated compensation (defined as an increase in pelvic retroversion (ΔRPV > 5º), and 33 did not (ΔRPV < 5º). The difference in behavior relied mostly on the amount of not surgically restored pelvic rotation at 6w (OR: 0.6; CI95%: 0.4-9.2; P = 0.017). Non-compensators had less rotation reserve (PTx100/PI = 33.9% vs 47.8%;P < 0.001) associated with worse 6w relative pelvic version and lower lumbar arc restoration, worse 6w relative sagittal alignment and GAP-score, compared with compensators (P < 0.001). Compensators' response was based on pelvic retroversion, causing lower lumbar arc decrease, lumbar apex caudal migration, and upper lumbar arc posterior inclination. Despite compensation, a thoracic kyphosis increase in both upper and lower arches gradually evolved into a PJK/PJF. Non-compensators did not react to PJK/PJF, which forced them into kyphosis from the lumbar apex and extending cranially, mainly throughout the upper thoracic arc.

CONCLUSIONS

In patients fused from the TL junction to the iliac, those having greater postoperative pelvic rotation reserve showed greater capacity to recruit compensatory mechanisms against PJK/PJF.

Predicting Reciprocal Thoracic Change, Proximal Junctional Kyphosis, and Revision Surgery in Adult Spinal Deformity

BACKGROUND

Compensatory mechanisms in patients with adult spinal deformity (ASD) that lead to poor quality of life include positive sagittal balance and pelvic retroversion. The objective of this retrospective review was to identify demographic and radiographic parameters of sagittal alignment that are correlated with thoracic kyphosis (TK), PJK, and reoperation in patients undergoing surgical correction for ASD.

METHODS

A single-center database of 155 patients with ASD undergoing surgery from 2008 to 2015 was reviewed. Patients >18 years old who underwent multilevel thoracolumbar fusion or fusion of thoracic vertebrae to the pelvis were included. Demographics and radiographic measurements of sagittal alignment were collected preoperatively, 6 weeks postoperatively, and 1 year postoperatively. Statistical analysis was performed to compare groups that did or did not develop change in thoracic kyphosis or PJK at early or late follow-up. Additionally, patients requiring reoperation were evaluated.

RESULTS

Increased thoracic kyphosis was associated with older age, hypolordosis, and comorbid PJK. Early PJK was associated with older age, hypolordosis, and increased T1 pelvic angle. Reoperation was associated with older age, higher positive sagittal balance, hypolordosis, and pelvic retroversion; PJK and thoracic kyphosis did not increase risk for reoperation.

CONCLUSIONS

Thoracic reciprocal change following surgical correction of ASD is highly associated with PJK, although neither increased risk of reoperation. PJK may be predicted by older age, hypolordosis, and increased T1 pelvic angle. Reoperation in patients with ASD is more likely in older patients with positive sagittal balance, a compensatory flat lower back, and compensatory pelvic retroversion.

Reduction of spondylolisthesis and sagittal balance correction by anterior lumbar interbody fusion (ALIF)

PURPOSE

Long time recognized as a cause of lumbar stenosis, degenerative spondylolisthesis has an evolution in interrelation with sagittal balance. This study aimed to assess the role of ALIF in correcting the sagittal balance in patients with degenerative spondylolisthesis.

MATERIAL AND METHODS

Twenty patients aged between 47 and 70 years were operated between July 2011 and September 2014 for degenerative spondylolisthesis by ALIF. The pre-operative and post-operative valid standing full spine radiographs were reviewed retrospectively. Clinical and radiological evaluations were conducted pre-operatively and postoperatively at one year and five years.

RESULTS

Lumbar lordosis (LL) was measured to 41.16 ± 14.25° pre-operatively and 47.27 ± 11.25° post-operatively (p > 0.05). At one year was 49.76 ± 13.31° and at five years 46.93 ± 9.26° (p > 0.05). Mean gain of lordosis after ALIF at index level was calculated to 8 ± 1.6° [4-12°].

CONCLUSIONS

ALIF offers a good reduction of the slipped vertebra providing good conditions for fusion and is an efficient surgical technique to recreate the sagittal spine balance.

The Berbeo-Sardi Angle (BSA): An Innovative Method to Effectively Estimate Pelvic Retroversion in Anteroposterior Radiographs-A Correlation With Traditional Parameters

STUDY

Design: Diagnostic studies-concordance between diagnostic tests.

OBJECTIVES

The purpose of this study was to develop a novel spinopelvic parameter (Berbeo-Sardi angle [BSA], the angle formed at the intersection of a line that connects the inferior margin of the sacroiliac joint to the midpoint of a horizontal line joining both femoral heads) measurable in anteroposterior radiographs that indirectly estimates pelvic retroversion and correlates with traditional measurements like pelvic tilt (PT).

SUMMARY

Sagittal balance appraisal and surgical planning rely on the interpretation of spinopelvic parameters. An increased PT reflects pelvic retroversion as a compensatory mechanism to limit sagittal imbalance and correlates with increased pain and disability. However, poor imaging techniques and incorrect patient positioning frequently hamper landmark identification in lateral radiographs, and with no measurable angles in anteroposterior radiographs, it is often impossible to determine PT and pelvic retroversion.

METHODS

Whole-spine radiographs from 105 consecutive patients were used to retrospectively measure conventional spinopelvic parameters and the BSA. Intraclass correlation coefficient was used to assess a quantitative correlation between the PT and BSA as indirect measures of pelvic retroversion.

RESULTS

Average values for pelvic incidence, lumbar lordosis, sacral slope, PT, and BSA were 46.5° (±10.23), 48.56° (±12.30), 29.97° (±9.77), 16.94° (±8.03), and 54.47° (±4.05), respectively. We encountered a moderately strong correlation (r = -0.66) between PT and BSA. Receiver operating characteristic plot analysis revealed that a BSA threshold of 46° has a sensitivity of 90% to identify pathologic PT values (>20°), whereas a BSA ≥60° has a specificity of 90% to rule out pelvic retroversion using anteroposterior radiographs.

CONCLUSIONS

There is a moderately strong correlation between the BSA, an innovative spinopelvic parameter measurable in anteroposterior radiographs, and PT. BSA seems to show great promise in simplifying spinopelvic appraisal by easily estimating pelvic retroversion associated with sagittal imbalance, while avoiding image-quality issues often encountered in lateral radiographs.

LEVEL OF EVIDENCE

Level III.

Evaluation of Sagittal Spine-Pelvis-Lower Limb Alignment in Elderly Women with Pelvic Retroversion while Standing and Walking Using a Three-Dimensional Musculoskeletal Model

Study Design

In vivo biomechanical study using a three-dimensional (3D) musculoskeletal model for elderly individuals with or without pelvic retroversion.

Purpose

To evaluate the effect of pelvic retroversion on the sagittal alignment of the spine, pelvis, and lower limb in elderly females while standing and walking.

Overview of Literature

Patients with hip–spine syndrome have concurrent hip-joint and spine diseases. However, the dynamic sagittal alignment between the hip joint and spine has rarely been investigated. We used a 3D musculoskeletal model to evaluate global spinopelvic parameters, including spinal inclination and pelvic tilt (PT).

Methods

A total of 32 ambulant females (mean age=78 years) without assistance were enrolled in the study. On the basis of the radiographic measurement for PT, participants were divided into the pelvic retroversion group (R-group; PT≥20°) and the normal group (N-group; PT<20°). A 3D musculoskeletal motion analysis system was used to analyze the calculated value for the alignment of spine, pelvis, and lower limb, including calculated (C)-PT, sagittal vertical axis (C-SVA), pelvic incidence, lumbar lordosis, T1 pelvic angle (C-TPA), as well as knee and hip flexion angles while standing and walking.

Results

While standing, C-PT and C-TPA in the R-group were significantly larger than those in the N-group. Hip angle was significantly smaller in the R-group than in the N-group, unlike knee angle, which did not show difference. While walking, C-SVA and C-TPA were significantly increased, whereas C-PT decreased compared with those while standing. The maximum hip-flexion angle was significantly smaller in the R-group than in the N-group. There was a significant correlation between the radiographic and calculated parameters.

Conclusions

The 3D musculoskeletal model was useful in evaluating the sagittal alignment of the spine, pelvis, and leg. Spinopelvic sagittal alignment showed deterioration while walking. C-PT was significantly decreased while walking in the R-group, indicating possible compensatory mechanisms attempting to increase coverage of the femoral head. The reduction in the hip flexion angle in the R-group was also considered as a compensatory mechanism.

Analysis of compensatory mechanisms in the pelvis and lower extremities in patients with pelvic incidence and lumbar lordosis mismatch

The objective was to analyze the compensatory effect of the pelvis and lower extremities on sagittal spinal malalignment in patients with pelvic incidence (PI) and lumbar lordosis (LL) mismatch. A series of parameters including PI, LL, PI-LL, thoracic kyphosis (TK), pelvic tilt (PT), sacral slope (SS), knee flexion angle (KFA), tibial obliquity angle (TOA), femoral obliquity angle (FOA), femur pelvis angle (FPA) and pelvic shift (PS) were measured. Patients with PI-LL mismatch were divided into pelvic retroversion group and pelvic retroposition group based on their PT and PS, and then the parameters were compared within the two groups and with the control group. All variables were significantly different when comparing the pelvic retroversion and retroposition group with the control group except for PI, FOA and PS in the pelvic retroversion group. The pelvic retroposition group had significantly greater value of PI-LL, PI, PT, KFA, FOA and PS and contribution ratio of FOA and PS, and smaller value of LL, TK and FPA and contribution ratio of PT, TOA and FPA compared with the pelvic retroversion group. Patients with lesser PI-LL mismatch rely more on hip extension to increase pelvic retroversion while those with greater PI-LL mismatch tend to add extra femoral obliquity. When compensating for larger PI-LL mismatch, the importance of hip extension is decreased and the effect of the knee and ankle joint becomes more important by providing greater femoral incline and relatively lesser ankle dorsiflexion respectively.