Etiology of developmental spinal stenosis: A genome-wide association study

Defining multilevel developmental cervical spinal stenosis using MRI

Aims

Developmental cervical spinal stenosis (DcSS) is a well-known predisposing factor for degenerative cervical myelopathy (DCM) but there is a lack of consensus on its definition. This study aims to define DcSS based on MRI, and its multilevel characteristics, to assess the prevalence of DcSS in the general population, and to evaluate the presence of DcSS in the prediction of developing DCM.

Methods

This cross-sectional study analyzed MRI spine morphological parameters at C3 to C7 (including anteroposterior (AP) diameter of spinal canal, spinal cord, and vertebral body) from DCM patients (n = 95) and individuals recruited from the general population (n = 2,019). Level-specific median AP spinal canal diameter from DCM patients was used to screen for stenotic levels in the population-based cohort. An individual with multilevel (≥ 3 vertebral levels) AP canal diameter smaller than the DCM median values was considered as having DcSS. The most optimal cut-off canal diameter per level for DcSS was determined by receiver operating characteristic analyses, and multivariable logistic regression was performed for the prediction of developing DCM that required surgery.

Results

A total of 2,114 individuals aged 64.6 years (SD 11.9) who underwent surgery from March 2009 to December 2016 were studied. The most optimal cut-off canal diameters for DcSS are: C3 < 12.9 mm, C4 < 11.8 mm, C5 < 11.9 mm, C6 < 12.3 mm, and C7 < 13.3 mm. Overall, 13.0% (262 of 2,019) of the population-based cohort had multilevel DcSS. Multilevel DcSS (odds ratio (OR) 6.12 (95% CI 3.97 to 9.42); p < 0.001) and male sex (OR 4.06 (95% CI 2.55 to 6.45); p < 0.001) were predictors of developing DCM.

Conclusion

This is the first MRI-based study for defining DcSS with multilevel canal narrowing. Level-specific cut-off canal diameters for DcSS can be used for early identification of individuals at risk of developing DCM. Individuals with DcSS at ≥ three levels and male sex are recommended for close monitoring or early intervention to avoid traumatic spinal cord injuries from stenosis.

Molecular landscape of congenital vertebral malformations: recent discoveries and future directions

Vertebral malformations (VMs) pose a significant global health problem, causing chronic pain and disability. Vertebral defects occur as isolated conditions or within the spectrum of various congenital disorders, such as Klippel-Feil syndrome, congenital scoliosis, spondylocostal dysostosis, sacral agenesis, and neural tube defects. Although both genetic abnormalities and environmental factors can contribute to abnormal vertebral development, our knowledge on molecular mechanisms of numerous VMs is still limited. Furthermore, there is a lack of resource that consolidates the current knowledge in this field. In this pioneering review, we provide a comprehensive analysis of the latest research on the molecular basis of VMs and the association of the VMs-related causative genes with bone developmental signaling pathways. Our study identifies 118 genes linked to VMs, with 98 genes involved in biological pathways crucial for the formation of the vertebral column. Overall, the review summarizes the current knowledge on VM genetics, and provides new insights into potential involvement of biological pathways in VM pathogenesis. We also present an overview of available data regarding the role of epigenetic and environmental factors in VMs. We identify areas where knowledge is lacking, such as precise molecular mechanisms in which specific genes contribute to the development of VMs. Finally, we propose future research avenues that could address knowledge gaps.

The correlation between lumbar interlaminar space size on plain radiograph and spinal stenosis

PURPOSE

Investigating the correlation between the interlaminar space size on plain radiograph and lumbar spinal stenosis (LSS).

METHODS

100 Patients with LSS and 100 normal participants without LSS were included in this study. Lumbar interlaminar parameters were measured on plain radiographs. Spinal canal parameters were measure on CT and MRI. These image parameters were compared between LSS and control group. The linear correlation among interlaminar parameters, spinal canal parameters and Oswestry Disability Index (ODI) were analyzed. The cut-off values of interlaminar parameters for diagnosing L3/4 and L4/5 symptomatic LSS were analyzed.

RESULTS

Excepting for L1/2 interlaminar width, all interlaminar and spinal canal related parameters in LSS group were significantly smaller than those in control group. Excepting for L1/2 interlaminar width and L5/S1 interlaminar height, all interlaminar parameters had significantly positive linear correlation with spinal canal parameters accordingly in each lumbar level. For diagnosis of symptomatic LSS, The cut off values of L4/5 interlaminar width, height and area were 18.46 mm, 11.37 mm and 134.05 mm2 while 15.78 mm, 13.59 mm and 157.98 mm2 in L3/4. Both spinal canal size and interlaminar size had no linear correlation with ODI in cases of L4/5 LSS.

CONCLUSIONS

Lumbar interlaminar space size on plain radiograph has positive linear correlation with developmental and degenerative LSS, excepting for L1/2 interlaminar width and L5/S1 interlaminar height. Lumbar plain radiograph can be a feasible way for predicting and helping to diagnose LSS through evaluating the interlaminar space size.

LEVEL OF EVIDENCE

III.

Incidence and Skeletal Features of Developmental Cervical and Lumbar Spinal Stenosis

STUDY DESIGN

Cross-sectional study.

PURPOSE

To report the prevalence and relationship of developmental cervical and lumbar spinal stenosis (DCSS and DLSS) with the bone parameters of the skull and extremities.

OVERVIEW OF LITERATURE

DCSS and DLSS are found occasionally in daily practice. DCSS and DLSS can cause compressive myelopathy, radiculopathy, and cauda equina syndrome; however, data on their prevalence and correlation with skull and skeletal extremity profiles is scarce.

METHODS

A cross-sectional measurement study of 293 whole-body dried-bone samples was conducted. We measured the anteroposterior (AP) and transverse diameter of the fourth to sixth cervical vertebrae (C4-C6) and third to fifth lumbar vertebrae (L3-L5). Stenosis of the cervical spine and lumbar spine was defined as an AP diameter of <12 mm and <13 mm, respectively. We also measured the skull circumference, the AP and transverse diameters of the foramen magnum, the inner and outer inter distances between the left and right orbital bones, the humerus length, and the femoral length. Kruskal-Wallis and post hoc analyses were used in the statistical analyses.

RESULTS

The age was 22-93 years. DCSS was found in 59 (20.1%) and DLSS in 28 (9.6%). Twelve samples had both DCSS and DLSS (development spinal stenosis, DSS). When compared to the "no spinal stenosis sample," DSS (-), DCSS and DSS had a significantly smaller skull circumference, the transverse diameter of the foramen magnum, and inner and outer distance between the orbital bone (p<0.05). There was no significant difference in humeral length, femoral length, or AP diameter of the foramen magnum.

CONCLUSIONS

DCSS was correlated with a small skull, a small transverse diameter of the foramen magnum, and a small orbital bone. A small skull was strongly associated with a small cervical canal. DLSS, on the other hand, was unrelated to either a small cervical canal or a small skull.

Comparison of PLIF and TLIF in the Treatment of LDH Complicated with Spinal Stenosis

Objective

The purpose was to compare the clinical effects of posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar disc herniation (LDH) complicated with spinal stenosis.

Methods

96 LDH patients complicated with spinal stenosis treated in our hospital (April 2018–April 2020) were chosen as the subjects, and split into the PLIF group and the TLIF group according to different surgical approaches, with 48 cases in each group. The clinical effects of the two groups were compared.

Results

There was no significant difference in hospitalization time between the two groups (P > 0.05). Compared with the PLIF group, the TLIF group had obviously shorter operation time and greatly lesser intraoperative blood loss (P < 0.05). The Numerical Rating Scale (NRS) scores of lower limb pain and low back pain in the two groups at 3 months after surgery were significantly lower than those before surgery (P < 0.001). The Japanese Orthopaedic Association (JOA) scores of the two groups at 3 months after surgery were significantly higher than those before surgery (P < 0.001). The Spitzer Quality of Life Index (SQLI) scores of the two groups at 3 months after surgery were significantly higher than those before surgery (P < 0.001).

Conclusion

The two surgical approaches have similar efficacy in treating LDH complicated with spinal stenosis. However, PLIF is better than TLIF in terms of operation time and intraoperative blood loss, which should be adopted as the preferred surgical scheme.

Pedigree analysis of lumbar developmental spinal stenosis: Determination of potential inheritance patterns

Lumbar developmental spinal stenosis (DSS) refers to multilevel pre-existing narrowed spinal canals, which predispose to neural compromise. The objective of this study is to identify any inheritance pattern of DSS by utilizing pedigree charts. This was a case series of 13 families with a total of 80 subjects having magnetic resonance imaging (MRI) from L1 to S1. Cases (subjects with DSS) or controls (subjects without DSS) were identified by measuring their anteroposterior (AP) vertebral canal diameters. Multilevel model analyses were also performed to evaluate whether there is substantial clustering of observations within the families, and the effect of multilevel DSS. The intraclass correlation coefficient (ICC) and Akaike information criteria (AIC) were compared between models. Correlations between subject demographics and AP vertebral canal diameter were statistically insignificant at all levels. Only vertebral canal cross-sectional area, and axial and sagittal vertebral canal diameter were found to be statistically different between cases and controls at all levels (all p < .05). Both males and females were affected by DSS and there was no skipping of generation, which highly suggested DSS followed an autosomal dominant inheritance pattern. After accounting for multilevel DSS, there was a drop of more than 10 in AIC and some variances were also explained within families. This is the first study that suggests multilevel lumbar DSS to have an autosomal dominant inheritance pattern. Within families with a background of DSS, subjects had a smaller canal size, contributed by shortened axial and sagittal AP vertebral canal diameter, and smaller canal cross-sectional area.

Genome-wide association studies of low back pain and lumbar spinal disorders using electronic health record data identify a locus associated with lumbar spinal stenosis

ABSTRACT

Identifying genetic risk factors for lumbar spine disorders may lead to knowledge regarding underlying mechanisms and the development of new treatments. We conducted a genome-wide association study involving 100,811 participants with genotypes and longitudinal electronic health record data from the Electronic Medical Records and Genomics Network and Geisinger Health. Cases and controls were defined using validated algorithms and clinical diagnostic codes. Electronic health record-defined phenotypes included low back pain requiring healthcare utilization (LBP-HC), lumbosacral radicular syndrome (LSRS), and lumbar spinal stenosis (LSS). Genome-wide association study used logistic regression with additive genetic effects adjusting for age, sex, site-specific factors, and ancestry (principal components). A fixed-effect inverse-variance weighted meta-analysis was conducted. Genetic variants of genome-wide significance (P < 5 × 10-8) were carried forward for replication in an independent sample from UK Biobank. Phenotype prevalence was 48.8% for LBP-HC, 19.8% for LSRS, and 7.9% for LSS. No variants were significantly associated with LBP-HC. One locus was associated with LSRS (lead variant rs146153280:C>G, odds ratio [OR] = 1.17 for G, P = 2.1 × 10-9), but was not replicated. Another locus on chromosome 2 spanning GFPT1, NFU1, and AAK1 was associated with LSS (lead variant rs13427243:G>A, OR = 1.10 for A, P = 4.3 × 10-8) and replicated in UK Biobank (OR = 1.11, P = 5.4 × 10-5). This was the first genome-wide association study meta-analysis of lumbar spinal disorders using electronic health record data. We identified 2 novel associations with LSRS and LSS; the latter was replicated in an independent sample.

Lumbar canal stenosis in "young" - How does it differ from that in "old" - An analysis of 116 surgically treated cases

Objective:

Patients treated for lumbar canal stenosis (LCS) were retrospectively analyzed to evaluate the differences in clinical management in those below (Group A) and those above (Group B) the age of 50 years. All patients were treated with the premise that instability is the nodal point of the pathogenesis of LCS and “only-stabilization” is the surgical treatment.

Materials and Methods:

During the period June 2014 to June 2020, 116 cases were diagnosed to have LCS and surgically treated by the Goel modification of Camille's transarticular screw fixation technique.

Results:

Twenty-four patients in Group A and six patients in Group B had a history of “significant” injury to the back at the onset of clinical symptoms. The indices suggested that the intensity of symptoms was relatively more severe in Group A than in Group B. Unilateral leg symptoms were more common in Group A (68%) than in Group B (31.8%). Neurological motor deficits were more common in Group A (28%) than in Group B (12%) patients. Spinal segments surgically treated in Group A ranged from 1 to 4 (average 2 levels) and in Group B it ranged from 2 to 5 (average 3 levels). During the follow-up period that ranged from 6 to 72 months (average 37 months), 100% of patients had varying degrees of relief from symptoms.

Conclusions:

LCS is confined to a lesser number of spinal segments in the Group A patients. The symptoms were radicular in nature and relatively severe in Group A than in Group B patients.

The identification of novel gene mutations for degenerative lumbar spinal stenosis using whole-exome sequencing in a Chinese cohort

BACKGROUND

Degenerative lumbar spinal stenosis (DLSS) is a common lumbar disease that requires surgery. Previous studies have indicated that genetic mutations are implicated in DLSS. However, studies on specific gene mutations are scarce. Whole-exome sequencing (WES) is a valuable research tool that identifies disease-causing genes and could become an effective strategy to investigate DLSS pathogenesis.

METHODS

From January 2016 to December 2017, we recruited 50 unrelated patients with symptoms consistent with DLSS and 25 unrelated healthy controls. We conducted WES and exome data analysis to identify susceptible genes. Allele mutations firstly identified potential DLSS variants in controls to the patients' group. We conducted a site-based association analysis to identify pathogenic variants using PolyPhen2, SIFT, Mutation Taster, Combined Annotation Dependent Depletion, and Phenolyzer algorithms. Potential variants were further confirmed using manual curation and validated using Sanger sequencing.

RESULTS

In this cohort, the major classification variant was missense_mutation, the major variant type was single nucleotide polymorphism (SNP), and the major single nucleotide variation was C > T. Multiple SNPs in 34 genes were identified when filtered allele mutations in controls to retain only patient mutations. Pathway enrichment analyses revealed that mutated genes were mainly enriched for immune response-related signaling pathways. Using the Novegene database, site-based associations revealed several novel variants, including HLA-DRB1, PARK2, ACTR8, AOAH, BCORL1, MKRN2, NRG4, NUP205 genes, etc., were DLSS related.

CONCLUSIONS

Our study revealed that deleterious mutations in several genes might contribute to DLSS etiology. By screening and confirming susceptibility genes using WES, we provided more information on disease pathogenesis. Further WES studies incorporating larger DLSS patient cohorts are required to comprehend the genetic landscape of DLSS pathophysiology fully.

Two GWAS-identified variants are associated with lumbar spinal stenosis and Gasdermin-C expression in Chinese population

The aim of this study is to investigate the expression levels of genome-wide association studies (GWAS)-identified variants near Gasdermin-C (GSDMC) and its association with lumbar disc degeneration (LDD) in a Chinese population. In accordance with previously reported findings, our study involved the top 4 variants; rs6651255, rs7833174, rs4130415, and rs7816342. A total of 800 participants, 400 LDD patients and 400 controls were involved in the study. The LDD patients were divided into two mutually exclusive subgroups: subgroup 1: lumbar disc herniation; subgroup 2: lumbar spinal stenosis. Genotyping were performed using TaqMan assay, and Enzyme-Linked Immunosorbent Assay (ELISA) used to measure the plasma GSDMC levels, while quantitative reverse-transcription (qRT)-PCR and immunohistochemistry (IHC) were used to evaluate the GSDMC expression levels. Among the studied variants, there were no statistically significant differences in allelic and genotypic frequencies between LDD patients and their controls (all P > 0.05). However, the subgroup analysis revealed a significant association between rs6651255 and rs7833174 in patients with lumbar spinal stenosis (subgroup 2). Furthermore, the max-statistic test revealed that the inheritance models of two variants of lumbar spinal stenosis were represented by the recessive model. The plasma and mRNA expression levels of GSDMC were significantly higher in patients with lumbar spinal stenosis compared with the control group (P < 0.05). Furthermore, the CC genotypes of rs6651255 and rs7833174 were significantly associated with increased plasma expression levels of GSDMC in patients with lumbar spinal stenosis (P < 0.01). Two GWAS-identified variants (rs6651255 and rs7833174) near GSDMC were associated with a predisposition to lumbar spinal stenosis. GSDMC protein and mRNA expression levels may have prognostic qualities as biomarkers for the existence, occurrence or development of lumbar spinal stenosis.

Novel compression rat model for developmental spinal stenosis

Developmental spinal stenosis (DSS) is characterized by pre-existing circumferential narrowing of the bony spinal canal which predisposes neural tissue to compression. This study aims to create a reproducible animal model mimicking DSS for investigation of its pathoanatomy. Developmental spinal canal constriction was simulated using circumferential compression. Eighteen female Sprague-Dawley rats (13.0-14.5 weeks-old) underwent circumferential compression at L4-L5 using silicone sheets; or dorsal compression using overlapping silicone sheets; or as controls. A series of outcome scores were used for locomotor function assessment, together with electrophysiological and histological assessment. Assessment time-points were at preoperative, postoperative 1-week, 2-weeks, 3-weeks, 1-month, and pre-sacrifice. Statistical analyses were performed. At all postoperative time-points, circumferential group had the worst mean Basso, Beattie and Bresnahan locomotor scores with significant difference from the control group (p < 0.05), as well as the lowest mean Louisville Swim Scale scores, as compared to the dorsal (p < 0.05) and to the control (p < 0.01) groups. Circumferential group had worse mean foot fault score for both hindlimbs (p < 0.01 to p < 0.05) and highest error rate in foot placement accuracy, especially higher than dorsal (p < 0.05) and control (p < 0.05) groups at pre-sacrifice. Electrophysiological assessment revealed postoperative increase in P1 latency was higher in circumferential than dorsal compression. Highest postoperative mean P1 latency was observed for both paws at all postoperative time-points for circumferential group (except at postoperative 1-week). Circumferential group had lower myelin-to-axonal area ratio and higher g-ratio than both the dorsal and control groups (p < 0.001). For each study group, hindlimb P1 latency and P1-N1 amplitude were each correlated with g-ratio (p < 0.05); and mean myelin-to-axonal area ratio correlated with P1 latency of both hindlimbs (p < 0.05). Based on these more severe axonal demyelination and neurological deficits, a valid DSS rat model is created with somatosensory evoked potential neuro-monitoring technique. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.