Risk Factors For the Development of a Mobile Degenerative Spondylolisthesis at L4-L5

Radiographic risk factors for degenerative lumbar spondylolisthesis: A comparison with healthy control subjects

Objective

To evaluate the radiologic parameters of degenerative lumbar spondylolisthesis (DLS) and determine the radiographic risk factors for DLS by making comparisons with healthy control subjects.

Methods

Seventy-five patients with L4/5 DLS (Meyerding grade I) and 53 healthy control subjects were analyzed. The L1-S1 disc height index (DHI), L4/5 facet joint angle (FJA), and relative cross-sectional area (RCSA) of paravertebral muscles were measured in both groups. The initial L4/5 DHI (iDHI) before the onset of DLS were estimated based on the L3/4 DHI of the DLS group and DHI of the control group. The sagittal parameters of DLS were also included in this study.

Results

The DHI of L4/5 was lower in the DLS group than in the control group (P < 0.05), but the DHI of the L1-L4 segments were much higher than in the control group (P < 0.05). The initial L4/5 DHI and FJA of the DLS group were significantly higher than those of the control group (P < 0.05). The RCSA of the paravertebral muscles were smaller in the DLS group than in the control group (P < 0.05). Binary logistic regression analysis showed that iDHI, FJA, and RCSA of the total paraspinal muscles were risk factors for DLS. The cutoff values for iDHI, FJA, and RCSA were 0.504, 56.968°, and 1.991 respectively. The iDHI was associated with lumbar lordosis (LL), while L4/5 DHI was associated with the RCSA of the multifidus muscle and psoas major muscle (P < 0.05).

Conclusion

A large initial lumbar disc height, large FJA, and paravertebral muscle atrophy may be risk factors for DLS.

The Reliability of CT Scan Measurements of Pelvic Incidence in the Evaluation of Adult Spondylolisthesis

Background: Pelvic incidence (PI) has been described as a parameter that may be a risk factor for lumbar spondylolisthesis (SPL). Studies have reported PI measurement is more precise in CT scans. Very limited studies have measured PI using CT scans to evaluate SPL. We analyzed the reliability of CT scans to measure PI to evaluate SPL and compared it to patients without SPL.

Methods: A retrospective, cross-sectional study of PI in a consecutive cohort of patients’ pelvic/abdominal CT scans from an emergency room visit at a Level 1 trauma center between 2013 and 2016. Inclusion criteria was >18 years and had no lumbar or pelvis fracture. A total of 361 patients met the criteria for our study. We documented age, average PI, and SPL (type, grading, and location). Sagittal CT scans were used to measure PI (between hip axis to an orthogonal line originating at the center of superior end plate axis of first sacral vertebra). Patients were categorized: with SPL (n=45) and without SPL (n=316). Subgroups were comprised based on the location of SPL (L4/L5 and L5/S1) and type of SPL. Analysis of variance (ANOVA) and chi-square tests used; p≤0.05 considered statistically significant.

Results: Patients with SPL were significantly older versus patients without SPL, p=0.006. There were no statistical differences in PI between patients with and without SPL (p=0.29); between subgroups of patients with SPL at L4/L5 and without SPL (p=0.52); between subgroups with type of SPL at L4/L5 and without SPL (p=0.47); and between SPL patients at L5/S1 and without SPL (p=0.40). Patients with isthmic SPL at L5/S1 had nearly significant higher PIs (p=0.06) compared to those without SPL or with degenerative SPL at L5/S1. There was a trend towards higher PI in Grade 2 SPL patients at L5/S1, p=0.18.

Conclusions: Patients with SPL were significantly older than patients without SPL. The two trends observed were that PI was higher in patients with isthmic SPL at L5/S1 and an increased PI with Grade 2 isthmic SPL at L5/S1. Our reported CT PI measurements correlated with reported PI measured using standard radiographs in patients with SPL. CT scans may be a reliable modality to evaluate adult SPL.

Facet Tropism in Lumbar Spine and Cervical Spine: A Systematic Review and Meta-Analysis

BACKGROUND

Facet tropism (FT) refers to the difference in the orientation of facet joints with respect to each other in the sagittal plane. FT leads to unequal biomechanical forces on facet joint and intervertebral disc during rotation and other physiologic movements. Most of the studies have reported the incidence of FT in the lumbar spine to vary between 40% and 70%, with L4-5 level being the most commonly afflicted level. The objective of this study was to find the association between FT and various lumbar and cervical degenerative disorders.

METHODS

A systematic search of PubMed was performed with the keywords "facet tropism" and "facet asymmetry." Data for meta-analysis were extracted from the studies to obtain pooled impact of FT on lumbar disc herniation (LDH) and lumbar degenerative spondylolisthesis (LDS).

RESULTS

Eighty-two articles were included in the systematic review and 18 studies had the required data to be included in the meta-analysis. The pooled standard mean difference between FT angles in patients with or without LDH was 0.31 with (P = 0.04). The pooled odds ratio for FT in patients with LDH was 3.27 with (P = 0.02). Subgroup analysis showed that there is no significant difference in the L3/4, L4/5, and L5S1 subgroups. The pooled standard mean difference between FT angles in patients with or without LDS was 0.54 (P = 0.009).

CONCLUSIONS

FT is significantly associated with LDH and LDS along with various other lumbar and cervical degenerative diseases.

Age- and sex-related changes in facet orientation and tropism in lower lumbar spine: an MRI study of 600 patients

PURPOSE

We aimed to determine the age- and sex-related changes in facet orientation and facet tropism in lower lumbar spine.

METHODS

Between June 2015 and December 2017, magnetic resonance imaging scans of the consecutive 600 patients performed in the outpatient department for low back pain were analyzed. The data were divided according to age into four groups: group A (< 30 years), group B (31-45 years), group C (46-60 years) and group D (> 60 years). The orientation of the facet angles at L3-4, L4-5 and L5-S1 was measured using the method described by Noren et al. Sagittal angles and tropism were determined at each level.

RESULTS

Average facet angle is noted to increase from L3-4 to L5-S1 level in all groups irrespective of age and sex. A positive correlation is noted between age and sagittal facet orientation at all levels across all groups. Tropism was noted to be statistically significant (p < 0.05) at L5-S1 level. L3-4 and L4-5 levels did not show a positive correlation with respect to age. Facet angle sagittalization was significantly associated in males at L5-S1 level (p < 0.05) and in females at L4-5 level (p < 0.05).

CONCLUSIONS

Predominant morphological changes in superior articular process are responsible for remodeling of facets that occur with increasing age, resulting in sagittalization. Even though the facet orientation changes over a period of time, differential changes within the facets at the same level might not be seen. These slides can be retrieved under Electronic Supplementary Material.

The Relationship of Facet Joint Orientation and Tropism with Lumbar Disc Herniation and Degenerative Spondylolisthesis in the Lower Lumbar Spine

STUDY DESIGN

Retrospective study.

PURPOSE

This study aimed to clarify the relationship of both facet tropism (FT) and the sagittally aligned facet (SAF) joint with lumbar disc herniation (LDH) and degenerative spondylolisthesis (DS).

OVERVIEW OF LITERATURE

Despite several studies conducted, there is no consensus on the association of the SAF joint and FT with DH and DS.

METHODS

Between June 2015 and December 2017, magnetic resonance imaging scans of 250 consecutive patients who underwent surgery for LDH and DS were analyzed. The facet angles at all the lower lumbar levels were calculated, and SAF and FT were noted. The relationship between the side of disc herniation and that of the SAF joint were also determined. Statistical analysis was performed, and the relation of SAF and FT to LDH and DS was noted.

RESULTS

We observed a positive relationship between SAF and LDH at L4-5 and L5-S1 with a p-value of 0.02 (<0.05). FT demonstrated a positive association with LDH at L4-5 (p=0.047) but not at L3-4 or L5-S1. SAF demonstrated a positive relationship with DS at L3-4 (p<0.001) but not at L3-4 or L5-S1. FT demonstrated a significant relation with DS at L4-5 (p<0.001), whereas no positive association was observed at L3-4 and L5-S1.

CONCLUSIONS

The L4-5 level demonstrated a significant association with SAF and FT in LDH and DS. Moreover, SAF at L5-S1 demonstrated a positive association with LDH. These findings provide useful information for future longitudinal studies to elucidate the possible causes for such phenomena.