Ligamentum Flavum Research Articles

Unilateral Approaches for Posterior Spinal Canal Decompression in Cervical Spondylotic Myelopathy—An Evaluation of Conceptual Feasibility

Patients with cervical spondylotic myelopathy (CSM) can be treated with posterior approaches for spinal canal decompression. We compared the patients' outcome after 2 different unilateral and a bilateral posterior approach for decompression to elucidate feasibility and potential procedure-related differences. Medical records of 98 patients with CSM undergoing posterior decompression between 2012 and 2018 were assessed. Patients were divided into 3 groups: (1) unilateral interlaminar fenestration with over-the-top "undercutting" (laminotomy) for compression limited to a ligamentum flavum hypertrophy, (2) unilateral hemilaminectomy for lateralized compression with a combination of ligamentous hypertrophy and osseus stenosis, and (3) laminectomy/laminoplasty for circular osseous-ligamentous spinal canal narrowing. The mean age was 73 years (m:f = 1.4:1), and most frequent symptoms (mean duration: 15 months) were ataxia (69%) and sensory changes (57%). Main location of stenoses (median Naganawa Score = 3; mean anteroposterior spinal canal diameter = 7.7 ± 2.2 mm) was C3 to C6. Thirty-one percent of the patients were assigned for a laminotomy procedure, 20% for a hemilaminectomy, and 49% for a laminectomy/laminoplasty. There were no significant differences of patients' characteristics, blood loss, and operation time between the 3 groups. Independent from the mode of surgery, the spinal canal was significantly widened (median Naganawa Score = 0; mean anteroposterior diameter = 11.4 ± 3.6 mm) and myelopathy (mJOA Score) improved ( P < .001); a higher body mass index was significantly correlated with a worse mJOA improvement (r = 0.293/ P = .003). Quality of life (Short-Form 36v2 Health Survey/Neck Disability Index) and reduction of the neck pain level were similar in the 3 groups at last follow-up (mean: 28 months). To minimize patients' periprocedural burden in CSM with dorsal compression, individual tailoring of the posterior approach according to the underlying compressive pathology achieves sufficient decompression and comparable long-term results.

Significance of body mass index on thoracic ossification of the ligamentum flavum in Chinese population.

To investigate the risk factors for thoracic ossification of the ligamentum flavum (TOLF), especially the relationship between BMI and TOLF. A total of 856 individuals consisting of 326 controls without ossification of spinal ligaments and 530 TOLF inpatients who underwent thoracic spine decompression surgery at our hospital between January 2013 and September 2020 were included. All subjects were classified into 4 grades: Grade 0) control; Grade 1) single-segment TOLF; Grade 2) multi-segment TOLF; and Grade 3) TOLF combined thoracic ossification of the posterior longitudinal ligament (T-OPLL). Logistic regression analysis was performed to identify the risk factors for TOLF. The TOLF index was calculated to assess the severity of TOLF, and its relationship with BMI was investigated by correlation analysis. Overall, TOLF patients are most numerous in the 50-59 age group. Age and gender were considered as independent risk factors for Grades 1 and 2. BMI was identified as an independent risk factor for TOLF. Furthermore, BMI was significantly higher in Grade 1 (26.1 VS 24.5kg/m2, P = 0.0001), Grade 2 (28.2 VS 24.5kg/m2, P < 0.0001), and Grade 3 (29.1 VS 24.5kg/m2, P < 0.0001) than Grade 0. Notably, in TOLF patients without combined T-OPLL, BMI was positively correlated with TOLF index, while BMI was negatively correlated with age in younger individuals. BMI is a crucial risk factor for TOLF. It highlights the necessity of close follow-up of asymptomatic TOLF patients with high BMI to detect and treat their TOLF progression promptly.

Indirect Effects on Adjacent Segments After Minimally Invasive Transforaminal Lumbar Interbody Fusion

To compare radiographic parameters at adjacent segments before and after minimally invasive transforaminal lumbar interbody fusion and assess relationships of radiographic changes between adjacent segments and fused level. Study participants included 44 patients who underwent minimally invasive transforaminal lumbar interbody fusion at L4-5 level. Radiographic parameters at adjacent segments (L3-4 and L5-S1) and clinical parameters were reviewed. Postoperative dural sac area significantly increased in upper (mean change 8.05 mm2, P < 0.001) and lower (14.08 mm2, P < 0.001) adjacent segments. Significant increases in SAPD were seen in upper (0.85 mm, P < 0.001) and lower (0.66 mm, P < 0.001) adjacent segments. Ligamentum flavum thickness significantly decreased in lower adjacent segments (-0.37 mm, P= 0.006). For every 1-mm increase in fused level disc height, lower SAPD increased 0.22 mm (P= 0.04), and lower segmental angle increased 0.91° (P= 0.04). For every 1° increase in fused level segmental angle, lower dural sac area increased 1.25 mm2 (P= 0.03), and lower SAPD increased 0.12 mm (P= 0.003). The 6- and 12-month postoperative visual analog scale back and leg scores significantly decreased compared with preoperatively (back: mean change-5.98 and-6.05, P < 0.001; leg:-6.86 and-6.89, P < 0.001). Performing minimally invasive transforaminal lumbar interbody fusion at the symptomatic index level does not worsen canal dimension of asymptomatic adjacent segments during short-term follow-up. It might be possible to improve canal dimension at adjacent segments by changing disc height or lordosis at the fused level via adjusting size and position of the interbody cage.

Diffuse Spinal Hyperostosis Causing Severe Spinal Stenosis and Thoracic Myelopathy.

Spinal stenosis has a wide range of causes including disc herniation, facet hypertrophy, degenerative spondylosis, facet cyst, ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament (OPLL). We present three cases of diffuse spinal hyperostosis causing severe spinal stenosis and myelopathy, which demonstrate a unique association between obesity and a novel syndrome of hyperostosis. This report describes 3 morbidly obese patients with diffuse spinal hyperostosis causing critical thoracic stenosis. Their presenting complaints focus on lower extremity weakness and the CT/MRI imaging is striking for diffuse hyper-ossification at thoracic levels. Two patients were subsequently managed with spinal decompression, and one patient was managed non-operatively. Metabolic changes associated with obesity may result in diffuse hyperostosis with ligament ossification and spinal stenosis. Pre-operative imaging is essential to identify the degree of ossification and potential dural involvement as this may complicate management.

Value of Additional Instrumented Fusion in the Treatment of Thoracic Ossification of the Ligamentum Flavum.

ObjectiveThe ossification of the ligamentum flavum (OLF) is one of the major causes of thoracic myelopathy. Surgical decompression with or without instrumented fusion is the mainstay of treatment. However, few studies have reported on the added effect of instrumented fusion. The objective of this study was to compare clinical and radiological outcomes between surgical decompression without instrumented fusion (D-group) and that with instrumented fusion (F-group). MethodsA retrospective review was performed on 28 patients (D-group, n=17; F-group, n=11) with thoracic myelopathy due to OLF. The clinical parameters compared included scores of the Japanese Orthopedic Association (JOA), the Visual analogue scale of the back and leg (VAS-B and VAS-L), and the Korean version of the Oswestry disability index (K-ODI). Radiological parameters included the sagittal vertical axis (SVA), the pelvic tilt (PT), the sacral slope (SS), the thoracic kyphosis angle (TKA), the segmental kyphosis angle (SKA) at the operated level, and the lumbar lordosis angle (LLA; a negative value implying lordosis). These parameters were measured preoperatively, 1 year postoperatively, and 2 years postoperatively, and were compared with a linear mixed model. ResultsAfter surgery, all clinical parameters were significantly improved in both groups, while VAS-L was more improved in the F-group than in the D-group (-3.4±2.5 vs. -1.3±2.2, p=0.008). Radiological outcomes were significantly different in terms of changes in TKA, SKA, and LLA. Changes in TKA, SKA, and LLA were 2.3°±4.7°, -0.1°±1.4°, and -1.3°±5.6° in the F-group, which were significantly lower than 6.8°±6.1°, 3.0°±2.8°, and 2.2°±5.3° in the D-group, respectively (p=0.013, p<0.0001, and p=0.037). Symptomatic recurrence of OLF occurred in one patient of the D-group at postoperative 24 months. ConclusionClinical improvement was achieved after decompression surgery for OLF regardless of whether instrumented fusion was added. However, adding instrumented fusion resulted in better outcomes in terms of lessening the progression of local and regional kyphosis and improving leg pain. Decompression with instrumented fusion may be a better surgical option for thoracic OLF.

P19. Effect of stature and lordosis on vertical falls in the female lumbar spine

P19. Effect of stature and lordosis on vertical falls in the female lumbar spine

P6. Normal anatomy of the lumbar sublaminar ridge in the lateral recess with potential implications to surgical technique in degenerative spinal stenosis: a cadaveric study

<h3>BACKGROUND CONTEXT</h3> The lateral extent of the lumbar sublaminar ridge – the bony, superior insertion site of the ligamenta flava – and its topological relationship to the nerve root are not yet described in the literature. In the setting of degenerative lumbar stenosis this structure can hypertrophy and impinge the nerve root within the lateral recess even after excision of the corresponding ligamentum flavum. Failure to address this may contribute to failed lateral recess decompression. <h3>PURPOSE</h3> To provide anatomic descriptions of the normal lumbar sublaminar ridge in the lateral recess and it's potential to impact on the exiting nerve root there, with implications to surgical technique in lumbar spinal stenosis. <h3>STUDY DESIGN/SETTING</h3> This was a dissection study of preserved cadaver donor specimes from the McMaster University Department of Anatomy. <h3>PATIENT SAMPLE</h3> Fifteen donor cadavers from the McMaster University Department of Anatomy. <h3>OUTCOME MEASURES</h3> Observed anatomy of the lumbar sublaminar ridge in the lateral recess and its relations to the exiting nerve root there. <h3>METHODS</h3> Fifteen lumbar vertebrae, not obviously degenerated, were resected en bloc from three fixed adult human cadavers and then transected through the ventral base of the pedicles immediately dorsal to the floor of the central spinal canal and the PLL, leaving the posterior column and neural elements intact and articulated. The shape of the sublaminar ridge in each of these 30 lateral recesses and its relationship to the exiting nerve root were carefully examined from the ventral aspect of these specimens (ie, from the deep surface of the [laminas and] lateral recesses). <h3>RESULTS</h3> The exiting nerve root consistently crosses the sublaminar ridge immediately inferior to the mid-pedicle, lateral to the subarticular gutter and on the medial aspect of the true intervertebral foramen. A hypertrophic ridge can compress the exiting root by elevating the nerve root superiorly against the bony underside of the pedicle or displacing it anteriorly against the disc or vertebral body. <h3>CONCLUSIONS</h3> The sublaminar ridge in the lateral recess commony crosses or underscores the exiting nerve root and so if hypertrophied might potentially contribute to degenerative lumbar stenosis. Comprehensive appreciation of this anatomy and the need at surgery in the lateral recess to confirm that the exit nerve root is not compressed or elevated by the sublaminar ridge may facilitate thorough lateral recess decompression. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

49 DCM-Related Degenerative Spinal Changes in the Healthy: Meta-Analysis &amp; Comparison to a Symptomatic Cohort

Abstract Aim Degenerative cervical myelopathy (DCM) is a progressive cervical spinal cord injury brought about by mechanical stress from degenerative changes in the cervical spine. It is typically diagnosed on clinical symptoms, examination findings together with MRI findings. The objective was to determine the significance of category of degenerative pathology (identified in Nouri et al, 2017) to onset of DCM, by comparing symptomatic and asymptomatic populations. Method A systematic review and meta-analysis were conducted in accordance with the PRISMA guidelines, cognizant of their adaptation for epidemiological studies. A search strategy was used to identify original research carrying out MRI screening of cervical spines of asymptomatic patients in MEDLINE and Embase from 1985 to the present day. Results The search yielded a total of 1,098 studies of which 17 were included in this meta-analysis, covering a total of 5,059 patients. Ossification of posterior longitudinal ligament (pooled asymptomatic prevalence of 0.4%), enlargement of ligamentum flavum (pooled asymptomatic prevalence of 11.8%) and degenerative multilevel disc pathology (pooled asymptomatic prevalence of 64.5%, I2 100%) were found to be significantly lower in asymptomatic populations (factor of 25 times, 4 times and 1.5 times respectively), and thus associated with DCM. Conclusions Ossification of posterior longitudinal ligament and enlargement of ligamentum flavum were found to be markedly lower in asymptomatic populations, possibly significantly implicating ligamentous pathology in the onset of DCM. Understanding the natural history of DCM is a recognised research priority, and whilst these perspectives require further evaluation, they may be of significance to the evolving biomechanical understanding of the disease.

P133. Measuring the radiographic efficacy of indirect decompression following minimally invasive lumbar interbody fusion: a computed tomography (CT) analysis study

<h3>BACKGROUND CONTEXT</h3> The advancement of MIS techniques has led to increased reliance on indirect decompression techniques. The latest generation of MIS TLIF cages are typically expandable cages that restore disc height and achieve ligamentum flavum unbuckling with associated increased central canal area. While prior studies have measured the extent of indirect decompression associated with ALIF and LLIF, the degree of decompression achieved via MIS-TLIF has not been described. <h3>PURPOSE</h3> Assess the degree of indirect decompression following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). <h3>STUDY DESIGN/SETTING</h3> Single-center, multi-surgeon, retrospective review. <h3>PATIENT SAMPLE</h3> Patients undergoing MIS-TLIF without direct decompression between 3/2017 and 3/2021. Patients were included if they had a pre- and postoperative CT scan. <h3>OUTCOME MEASURES</h3> Pre- and postoperative CT scans were used to measure disc height, foraminal area (left and right) and central canal area at the operative level(s). The most recent postoperative patient reported outcome measures (PROMs) between 6 months and 2 years were used to compare against preoperative values. <h3>METHODS</h3> Postoperative CT was performed at 1-43 months based on surgeon-specific protocols. Both pre- and postoperative CT measurements were performed by two observers. PROMs were collected in a prospectively maintained database. Paired tests were used to compare changes in CT measurements and PROMs. Bivariate analysis was also done to assess correlations between the changes in CT measures and PROMs improvement. <h3>RESULTS</h3> A total of 40 patients (48 operative levels) were assessed; 16 (33.3%) of the subjects were female and 24 (50%) were male. The average age was 56.6 ± 15.9 years. The average length of follow-up was 17.9 ± 7.9 months for PROMs and 13.5 ± 9.3 months for postoperative CT imaging. There were 32 (80%) single-level and 8 (20%) two-level cases, with 23 (47.9%) operated at L4L5 and 25 (52.1%) at L5S1. Disc height, foraminal area, and central canal area all increased significantly (p < 0.001). Mean disc height increased 50%, from 4.2 to 6.3mm. Right sided foraminal area increased 23%, from 144 .5 to 177.8mm2, the left increased 21.4% from 142.8 to 173.4mm2, and the central canal increased 16.4% from 228.6 to 266 mm2. All PROMs except for SF12-MCS (p=0.439) showed a statistically significant improvement (p < 0.05). There was no correlation between each change in PROM and the increase in cross sectional canal area. <h3>CONCLUSIONS</h3> MIS-TLIF provides a significant degree of indirect decompression. Disc height, foraminal area and central canal area were all increased following insertion of the interbody cage via the MIS-TLIF technique. PROMs by 2 years demonstrated a statistically significant improvement. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Best cutoff score of cervical-pedicle thickness as a morphological parameter for predicting cervical central stenosis.

There are various factors for the cause of cervical central stenosis (CCS), such as osteophyte, cervical-disc degeneration, and cervical ligamentum flavum hypertrophy. However, the pedicle of the cervical vertebra has not yet been analyzed for its relationship with CCS. We created a new morphologic parameter called the cervical-pedicle thickness (CPT) to assess the association between CCS and the cervical pedicle.We obtained morphological cases involving the CPT from 82 patients with CCS. There were also 84 in the normal group who underwent cervical spine magnetic resonance imaging (CS-MR) as part of routine health screening. We obtained the T2-weighted CS-MR axial images from group members, and assessed the CPT at the level of the C6 vertebra on CS-MR.The mean CPT was 3.46 ± 0.57 mm in the normal group, 4.97 ± 0.75 mm in the CCS group, which thus had a significantly higher CPT (P < .01) than did the normal group. For the prognostic value of the CPT as a predictor of CCS, ROC analysis indicated that the best cutoff score for the CPT was 4.18 mm, with 93.9% sensitivity, 92.9% specificity, and AUC 0.97.Greater CPT was highly associated with a possibility of CCS. This conclusion will be helpful for assessing the CCS patients.

High Systemic Immune-Inflammation Index and Body Mass Index Are Independent Risk Factors of the Thoracic Ossification of the Ligamentum Flavum.

Background Inflammation has been considered to play an important role in the pathogenesis of the thoracic ossification of the ligamentum flavum (OLF). However, the inflammation-related risk factors of thoracic OLF have not been fully investigated to date. Methods A total of 95 patients (48 in the OLF group and 47 in the control group) were included in this retrospective study to explore the independent risk factors of thoracic OLF. The following demographic and clinical variables were compared between the two groups: gender, age, body mass index (BMI), coexistence of hypertension or diabetes, and inflammation-related variables. Multivariate logistic regression analysis was utilized to determine the independent risk factors. Results High systemic immune-inflammation index (SII) (≥621) (odds ratio [OR] = 12.16, 95% confidence interval [CI] = 2.95–50.17, p < 0.01) and BMI (≥25 kg/m2) (OR = 9.17, 95%CI = 3.22–26.08, p < 0.01) were independent risk factors of thoracic OLF. SII (R = 0.38, p < 0.01) and BMI (R = 0.46, p < 0.01) were positively associated with OLF score. Conclusion High SII and BMI were the independent risk factors of thoracic OLF. Multicenter prospective studies with a large population should be conducted in the future to verify our findings.

Immune cell infiltration and the genes associated with ligamentum flavum hypertrophy: Identification and validation.

Ligamentum flavum hypertrophy (LFH) is a common cause of spinal stenosis. The aim of the current study was to identify the differentially expressed genes (DEGs) in LFH and the molecular mechanisms underlying the development of and immune responses to LFH. The gene expression omnibus (GEO) database was used to obtain the GSE113212 dataset, and the DEGs were derived from microarray data. To identify critical genes and signaling pathways, gene ontology enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network analyses were performed, followed by immune cell infiltration and Friends analyses using the retrieved datasets. The results were validated using quantitative real-time PCR. The 1530 DEGs identified comprised 971 upregulated and 559 downregulated genes. KEGG analysis revealed that DEGs were mostly enriched in the PI3K-Akt signaling pathway, while PPI network analysis identified tumor necrosis factor, interleukin (IL)-6, IL-10, epidermal growth factor receptor, and leptin as important nodes, which was validated by qPCR and IHC in human LFH tissues in vitro. A significant positive correlation was found between key LFH immune-related DEGs and several immune cell types, including T and B cells. The findings of the present study might lead to novel therapeutic targets and clinical approaches, as they provide insights into the molecular mechanisms of LFH.

The cervical sagittal curvature change in patients with or without PCSM after laminoplasty.

ObjectiveAfter laminoplasty, the cervical sagittal curvature of some patients tend to be lordotic, this phenomenon cannot be explained by the theory of laminoplasty, and the reason remains unknown. We explored the possible role played by pinching cervical spondylotic myelopathy (PCSM) in the cervical sagittal curvature change in patients after laminoplasty.MethodsFrom April 2017 to May 2019, we studied 122 patients undergoing laminoplasty with cervical spondylotic myelopathy (CSM). All patients were divided into Group A (anterior compression only, without PCSM) and Group B (both anterior and posterior compression, with PCSM). The visual analogue scale (VAS) was used to measure pain, and modified Japanese Orthopedic Association (mJOA) score was derived. The cervical global angle (CGA) and the range of cervical motion (ROM) were compared. The clinical and imaging results were compared between Group A and Group B.ResultsAfter laminoplasty, both the mean VAS and mJOA scores improved significantly in Group A and Group B, the mJOA recovery rate of Group B was better than that of Group A (P < 0.05). The mean CGA and ROM decreased in Group A, but increased in Group B. MRI revealed that the ligamentum flavum of Group A was significantly thinner than that of Group B (P < 0.05).ConclusionsBecause of the hypertrophic and folded ligamentum flavum compressing the dorsal spinal cord, patients with PCSM may maintain a compulsive kyphotic posture. After laminoplasty, the cervical sagittal curvature of these patients tend to be lordotic due to the release of dorsal spinal cord compression.

Analysis of lumbar spine stenosis specimens for identification of amyloid.

Lumbar spinal stenosis (LSS) is a common reason for spine surgery in which ligamentum flavum is resected. Transthyretin (TTR) amyloid is an often unrecognized and potentially modifiable mechanism for LSS that can also cause TTR cardiac amyloidosis. Accordingly, older adult patients undergoing lumbar spine (LS) surgery were evaluated for amyloid and if present, the precursor protein, as well as comprehensive characterization of the clinical phenotype. A prospective, cohort study in 2 academic medical centers enrolled 47 subjects (age 69 ± 7 years, 53% male) undergoing clinically indicated LS decompression. The presence of amyloid was evaluated by Congo Red staining and in those with amyloid, precursor protein was determined by laser capture microdissection coupled to mass spectrometry (LCM-MS). The phenotype was assessed by disease-specific questionnaires (Swiss Spinal Stenosis Questionnaire and Kansas City Cardiomyopathy Questionnaire) and the 36-question short-form health survey, as well as biochemical measures (TTR, retinol-binding protein, and TTR stability). Cardiac testing included technetium-99m-pyrophosphate scintigraphy, electrocardiograms, echocardiograms, and cardiac biomarkers as well as measures of functional capacity. Amyloid was detected in 16 samples (34% of participants) and was more common in those aged ≥ 75 years of age (66.7%) compared with those <75 years (22.3%, p < 0.05). LCM-MS demonstrated TTR as the precursor protein in 62.5% of participants with amyloid while 37.5% had an indeterminant type of amyloid. Demographic, clinical, quality-of-life measures, electrocardiographic, echocardiographic, and biochemical measures did not differ between those with and without amyloid. Among those with TTR amyloid (n=10), one subject had cardiac involvement by scintigraphy. Amyloid is detected in more than a third of older adults undergoing LSS. Amyloid is more common with advancing age and is particularly common in those >75 years old. No demographic, clinical, biochemical, or cardiac parameter distinguished those with and without amyloid. In more than half of subjects with LS amyloid, the precursor protein was TTR indicating the importance of pathological assessment.

IL-6 is involved in thoracic ossification of the ligamentum flavum.

Thoracic ossification of the ligamentum flavum (TOLF) is a heterotopic ossification of spinal ligaments. TOLF is the major cause of thoracic spinal canal stenosis and myelopathy, and its underlying mechanisms are not clear. Bone formation is a complex developmental process involving the differentiation of mesenchymal stem cells to osteoblasts, and regulated by BMP2, RUNX2, Osterix (OSX), etc. In this study, we continue to further characterize properties of TOLF. Our immunohistochemistry experiments showed that expressions of osteoblastic factors such as BMP2 and RUNX2 increased in TOLF. According to flow cytometry analysis the proportion of S phase of cell cycle in primary TOLF cells was 9% higher than the control. Alizarin red staining and ALP staining observations were consistent with immunohistochemistry results. It was also observed that inflammatory cytokine IL-6 level dramatically increased in the culture supernatant of primary TOLF cells. We propose the hypothesis that IL-6 is involved in TOLF. To testify the hypothesis, we examined the effect of IL-6. Our results showed that IL-6 was able to activate expressions of osteoblastic factors such as BMP2, RUNX2, OSX, OCN and ALP, and that expressions of cell proliferation factors cyclin D1 and cyclin C increased in the presence of IL-6. Moreover, IL-6-induced BMP2 expression was inhibited by p38 inhibitor SB203580, indicating that IL-6 regulated the osteogenic BMP2 activation through p38 MAPK pathway. These data suggest that IL-6 is involved in TOLF.

Macrophage migration inhibitory factor takes part in the lumbar ligamentum flavum hypertrophy.

The present study aimed to observe the content difference of macrophage migration inhibitory factor [MIF; novoprotein recombinant human MIF (n-6his) (ch33)], TGFβ1 and MMP13 in patients with and without ligamentum flavum (LF) hypertrophy and investigate the roles of MIF in LF hypertrophy. The concentration of MIF, TGFβ1 and MMP13 in LF were detected by ELISA in a lumbar spinal stenosis (LSS) group and a lumbar disc herniation (LDH) group. Culture of primary LFs and identification were performed for the subsequent study. Cell treatments and cell proliferation assay by CCK-8 was performed. Western blot and quantitative PCR analysis were used to detect the expression of TGFβ1, MMP13, type I collagen (COL-1) and type III collagen (COL-3) and Src which were promoted by MIF. The concentration of MIF, TGFβ1 and MMP13 were higher in the LSS group compared with the LDH group. Culture of primary LFs and identification were performed. Significant difference in LFs proliferation occurred with treatment by MIF at a concentration of 40 nM for 48 h (P<0.05). The gene and protein expression of TGFβ1, MMP13, COL-1, COL-3 and Src were promoted by MIF (P<0.05). Proliferation of LFs was induced by MIF and MIF-induced proliferation of LFs was inhibited by PP1 (a Src inhibitor). MIF may promote the proliferation of LFs through the Src kinase signaling pathway and can promote extracellular matrix changes by its pro-inflammatory effect. MIF and its mediated inflammatory reaction are driving factors of LF hypertrophy.

Equipoise for Lateral Access Surgery

To investigate the use of lateral access surgery among surgeons from the Asia-Pacific region to determine equipoise for areas of contentious use. A questionnaire was distributed to members of the Asia Pacific Spine Society. Surgeons were asked about their past experiences with lateral access surgery, including their advantages and disadvantages, specific surgical strategies, choices in implant-related factors, order of levels to operate on in multilevel reconstruction surgery, and postoperative complications. A total of 69 of 102 surgeons (67.6%) had performed lateral access surgery previously. In total, 56 participating surgeons (54.9%) agreed that anterior column reconstruction via lateral access is most of time superior to transforaminal lumbar interbody fusion and other techniques. Surgeons would consider laminectomy instead of indirect decompression in the presence of severe central or lateral recess stenosis, thickened ligamentum flavum, and facet joint hypertrophy. For the order of levels to operate on in multiple level reconstruction for deformity, where 1 stands for L3-L4 or higher, 2 stands for L4-L5, and 3 stands for L5-S1, 2-1-3 (28/95, 29.5%) was most common, followed by 1-2-3 (26/95, 27.4%), and 3-2-1 (21/95, 22.1%). Lateral access surgery is seeing greater use in the Asia-Pacific region, especially in upper middle- to high-income countries, whereas keenness of surgeons who practice in lower middle- to low-income countries can be improved by more training, resources, and reasonable cost. A high percentage of surgeons do not consider indirect decompression for spinal stenosis. There was no consensus on the order of levels in multiple level reconstruction for deformity.

High Body Mass Index Is Associated with an Increased Risk of the Onset and Severity of Ossification of Spinal Ligaments.

BackgroundOssification of the posterior longitudinal ligament (OPLL) and that of ligamentum flavum (OLF) are the main types of the ossification of spinal ligaments (OSL) that cause the thoracic myelopathy. Although several studies have investigated the relationship of body mass index (BMI) with the onset or severity of OSL, it remains unverified due to the contradictory results of existing evidence. A systematic review and meta-analysis were performed in this work to determine the relationship of BMI with the onset and severity of OSL.MethodsPubMed, EMBASE, Web of Science, and Cochrane Library were comprehensively searched online for relevant studies focusing on the relationship of BMI with the onset or severity of the OSL. The difference in BMI of OSL (or severe OSL group) and non-OSL (or nonsevere OSL group) groups was evaluated using the mean difference (MD) with a corresponding 95% confidence interval (CI).ResultsFifteen studies were included in this systematic review and meta-analysis. The BMI of the OSL group was significantly higher than that of the non-OSL group (MD = 1.70 kg/m2, 95% CI = 1.02–2.39 kg/m2, and P < 0.01). Similar results were observed in the subgroup analysis of female (P < 0.01), OPLL (P < 0.01), and OLF (P < 0.01) populations. Three studies reported a significant association of BMI with the ossification index of OSL and the standardized regression coefficient ranging from 0.11 to 0.43 (P < 0.05). Moreover, a significantly higher BMI was observed in the severe OSL group compared with that in the nonsevere OSL group (MD = 3.09, 95% CI, 0.22–5.97 kg/m2, and P = 0.04).ConclusionThe significant association of high BMI with the onset and severity of OSL may provide new evidence and insights into the mechanism research and management of OSL.

Progression of Spinal Ligament Ossification in Patients with Thoracic Myelopathy

ObjectiveTo evaluate the rate of increase in thickness and cross‐section area (CSA) of the ossification in thoracic myelopathy with or without cervical and lumbar spinal ligament ossification.MethodsA total of 24 patients with 170 segments (47 ligamentum flavum [OLF] and 123 cases of ossification of the posterior longitudinal ligament [OPLL]) of spinal ligament ossification between January 2012 and March 2019 at a single institution were retrospectively reviewed. Demographic data, classification of OPLL, Sato classification of OLF, pre‐ and postoperative neurological function and complications were recorded. The thickness and CSA at the segment of maximum compression were measured with Image J software on the axial CT image.ResultsTwelve female and 12 male patients with thoracic myelopathy and spinal ligament ossification were enrolled in the study. The mean age of the patients was 54.0 ± 11.9 years with an average follow‐up of 22.2 ± 23.5 months. Overall, the mean rate of progression in thickness and CSA was 1.2 ± 1.6 and 18.4 ± 50.6 mm2/year, respectively. Being female, aging (≥45 years), and lower BMI (<28 kg/m2) predisposed patients to have faster ossification growth in thickness and CSA. The difference between the rate of OPLL and OLF progression in thickness and CSA was not significant. However, the rate of OPLL progression in the thoracic spine was significantly higher than that in the cervical spine regarding thickness (1.4 ± 1.9 vs. 0.6 ± 0.7 mm/year) and CSA (27.7 ± 72.0 vs. 7.3 ± 10.3 mm2/year).ConclusionThis is the first study to investigate ligament ossification progression in patients with thoracic myelopathy. The difference between the rate of OPLL and OLF progression in thickness and CSA was not significant. However, the rate of thoracic OPLL progression in thickness and CSA was significantly higher than that in the cervical spine.

Pectus excavatum, kyphoscoliosis associated with thoracolumbar spinal stenosis: a rare case report and literature review

BackgroundPectus excavatum is the most common congenital chest wall defect. Thoracolumbar spinal stenosis and kyphoscoliosis was seen in patients with pectus excavatum. It can be caused by ossification of the ligamentum flavum, which is rare in patients with pectus excavatum.Case presentationWe reported a 26-year-old woman presented bilateral lower extremities weakness and numbness for two months, progressive worsening. She was diagnosed as thoracolumbar spinal stenosis with ossification of the ligamentum flavum, thoracolumbar kyphoscoliosis associated with pectus excavatum. The posterior instrumentation, decompression with laminectomy, and de-kyposis procedure with multilevel ponte osteotomy were performed. Her postoperative course was uneventful and followed up regularly. Good neurologic symptoms improvement and spinal alignment were achieved.ConclusionsPectus excavatum, kyphoscoliosis associated with thoracolumbar spinal stenosis is rare, and thus her treatment options are very challengeable. Extensive laminectomy decompression and de-kyphosis procedures can achieve good improvement of neurologic impingement and spinal alignment.