Ligamentum Flavum Research Articles

Correlation between Vertebral Slippage in Spondylolisthesis with Ligamentum Flavum Thickening in Dr. Soebandi Hospital, Jember, East Java, Indonesia

Background: Spondylolisthesis is a vertebral slip condition that compromises the body’s axial alignment and structures such as ligamentum flavum. The ligamentum flavum thickening may play a role in spondylolisthesis. The purpose of this study was to investigate the correlation between the slippage of vertebral body (spondylolisthesis) with ligamentum flavum thickening as a tissue response regarding increased mechanical stress.Methods: An analytical retrospective radiological observational was used a cross-sectional study from the results of MRI examination in Dr. Soebandi Hospital, Jember, Indonesia, collected from 2018-2021 using the simple random sampling method. Ligamentum flavum thickness and the degree of vertebral slip were measured using T2-weighted MR imaging and the correlation was analyzed using Fisher’s exact test. Results: Of 102 spondylolisthesis data records, 34 were taken, being female was the most prevalent cases in the age group above 60 years, with the most vertebral segment shift occurring at the L4–L5 level. There was a significant correlation. (p = 0.02; RR = 4.8) between ligamentum flavum thickening and vertebral slip in spondylolisthesis. Conclusion: The significant correlation between ligamentum flavum thickening and vertebral slip in spondylolisthesis suggest that mechanical stress has caused spondylolisthesis, by inducing chronic inflammation that results in hypertrophy of ligamentum flavum. Lumbar segmental instability due to spondylolisthesis is a factor contributing to the development of ligamentum flavum hypertrophy.

Biportal Endoscopic Posterior Thoracic Laminectomy for Thoracic Spondylotic Myelopathy Caused by Ossification of the Ligamentum Flavum: Technical Developments and Outcomes.

Advanced biportal endoscopic surgery techniques can be used to treat thoracic myelopathy secondary to ossification of the ligamentum flavum (OLF). This case series elaborates on a feasible biportal endoscopic technique for thoracic OLF removal and evaluates clinical and radiological outcomes. A biportal endoscopic posterior thoracic laminectomy was performed to remove the thoracic OLF. Surgical techniques have evolved from inside-out piecemeal removal methods to outside-in en bloc removal methods. Preoperative computed tomography was performed to analyze dural ossification and OLF types. Intraoperative videos were reviewed to observe dural ossification and to determine the surgical method. Neurological outcomes were assessed using the Japanese Orthopaedic Association (JOA) score. Clinical symptoms and neurological function improved markedly after surgery (JOA score, preoperative: 12.6 ± 1.0, final follow-up: 15.6 ± 1.2). The mean operation time per segment was not short (106.6 ± 38 minutes). At early experience stages, inside-out piecemeal decompression was used and it caused intraoperative spinal cord injury. However, outside-in en bloc decompression technique did not induce neural complications. Postoperative segmental instability and correlated mechanical back pain were not observed. The biportal endoscopic posterior thoracic approach is an attractive surgical option to treat thoracic spondylotic myelopathy secondary to OLF. Piecemeal inside-out decompression can induce irreversible spinal cord injury, especially in the early experience stages. Outside-in decompression is more efficient and safer than inside-out pattern procedures by minimizing dural manipulation. Nonetheless, this technique is technically demanding and should only be performed in selected patients after acquiring abundant experience with endoscopic spine surgeries.

Facet Articular Irregularity Is the Most Relevant Risk Factor for Rapidly Progressive Degenerative Cervical Myelopathy.

Facet articular irregularity is associated with rapidly progressive degenerative cervical myelopathy (DCM). However, its significance compared with other known risk factors remains unknown. Therefore, this retrospective study aimed to clarify the potential impact of facet articular irregularity as a risk factor for rapid DCM progression. This study included 141 consecutive patients with DCM who underwent surgical treatment at our institution. Clinical variables and radiological findings related to DCM progression were collected. Imaging findings were analyzed at the segmental level of myelopathy in each case. The patients were divided into 2 groups based on the presence or absence of rapid DCM progression, and independent risk factors were determined using logistic regression analyses. Overall, 131 patients with a mean age of 63.9 ± 12.6 years were analyzed; 27 patients (20.6%) were classified into the rapid DCM progression group. The mean age was significantly higher in the rapid progression group than in the slow progression group (72.4 ± 9.6 vs. 61.7 ± 12.4, p < 0.001). According to univariate analysis, facet articular irregularity, dynamic segmental translation (≥ 1.6 mm), upper cervical spine involvement above C4-5, history of cerebrovascular events, preceding minor trauma, local lordotic angle (≥ 4.5°), diabetes, hypertension, ligamentum flavum hypertrophy, and age were independent risk factors. Additionally, multivariate analysis showed that facet articular irregularity was the highest risk factor for rapid DCM progression (p = 0.001). Facet articular irregularity is the most clinically significant finding among the known risk factors in patients with rapid DCM progression.

Surgical outcome of lower limbs radiculopathy “due to degenerative lumbar canal stenosis” 12-24 months after decompression

Objectives: Interlaminar decompression is a surgical procedure that decompresses the lumbar spinal canal in order to release neuro-vascular components that have been compromised by degenerative stenosis. It can significantly improve patient quality of life and reduce morbidity and the effects of lumbar canal stenosis.&#x0D; Methods: A retrospective study of 57 patients, surgically operated for degenerative lumbar canal stenosis, at the Sulaymaniyah teaching hospital between Mar. 2018 and Mar. 2020.&#x0D; Diagnosis was achieved via history and clinical examination and radiological imaging (Lumbo-sacral spine MRI). Surgical procedure was standardized for all patients that was interlaminar decompression of the lumbar spinal canal, the postoperative follow up was after 12-24 months.&#x0D; Results: In total, 57 patients with degenerative lumbar canal stenosis (due to ligamentum flavum hypertrophy) were included, male (26%) and female (74%), age of the cases were between 34 – 85 years, mean 57.39 and median 57 and standard deviation 10.96, there were no deference in the outcome of different ages and genders.&#x0D; chief complain of patients were back pain and both lower limbs radiculopathy in the majority of the cases, associated with paresthesia and numbness of the lower limbs, which were improved modestly after surgical decompression.&#x0D; Conclusion: Interlaminar decompression of the stenosed lumbar spinal canal is an effective and generally safe surgical procedure with high patient satisfaction and good functional outcomes expected.

Thoracic spondylotic myelopathy in diffuse idiopathic skeletal hyperostosis: a comparative study

BackgroundTo explore the characteristics and clinical management of thoracic spinal stenosis with diffuse idiopathic skeletal hyperostosis (DISH).MethodsThe patients diagnosed with thoracic spondylotic myelopathy who underwent spinal decompression and fusion surgery in a single center between 2012 and 2020 were retrospectively analyzed. All the patients were followed up for at least 2 years. Patients were classified into DISH and non-DISH groups. Demographic, radiographic and clinical parameters were compared between the two groups.ResultsA total of 100 thoracic spondylotic myelopathy patients were included in the study. 22 patients were diagnosed with DISH. The proportion of male patients in the DISH group was higher, and the average BMI was larger. The incidence of upper thoracic vertebrae with ossification of posterior longitudinal ligament (OPLL) (P < 0.05) and lumbar spine with ossification of ligamentum flavum (OLF) was higher (P < 0.05) in DISH the group. The proportion of patients received staged surgery is higher in the DISH group (P < 0.1). There were no significant differences between the two groups in the amount of surgical bleeding, the ratio of cerebrospinal fluid leakage, the time duration of drainage tube placement and the JOA scores.ConclusionThoracic spinal stenosis with DISH occurred more in male patients with larger BMI. The posterior decompression and fusion surgery could achieve comparable satisfying clinical outcomes between DISH and non-DISH patients. More proportion of patients received staged surgery in the DISH group; the underline mechanism may be DISH caused more OPLL in the upper thoracic spine and more OLF in the lumbar spine because of mechanical stress.

Ligamentum flavum analysis in patients with lumbar discus hernia and lumbar spinal stenosis

The normal ligamentum flavum (LF) is a well-defined elastic structure with specific innervation. Several studies investigated LF in patients with lumbar spinal stenosis (LSS) and used lumbar discus hernia (LDH) patients as control group, only on the presumed thesis that LF in this patients have normal morphology. In patients with LSS thickening of the LF is the main cause of stenosis, which is most often presented with neurogenic claudication, whose pathophysiological mechanism is not completely understood. We conducted observational cohort study of 60 operated patients divided into two groups. The first group of 30 patients underwent micro-discectomy (LSH group), and second group with 30 patients underwent decompression, after which analysis of harvested LF was performed. Patients from the LDH group and LSS group differed significantly in the frequencies of chief complaints, duration of symptoms, physical examination, and specific morphological/radiological parameters. The LF analysis showed that the groups differed significantly in the amount of collagen and elastic fibers, as well as in the histological appearance/architectonics of elastic fibers. Also, groups differ in the presence of LF nerve fibers. Our findings speak in favor of the recently postulated inflammatory theory in the origin of spinal neurogenic claudication’s.

Prevalence, diagnosis, and impact on clinical outcomes of dural ossification in the thoracic ossification of the ligamentum flavum: a systematic review.

Systematic review. Thoracic ossification of the ligamentum flavum (TOLF) has become the principal cause of thoracic spinal stenosis. Dural ossification (DO) was a common clinical feature accompanying with TOLF. However, on account of the rarity, we know little about the DO in TOLF so far. This study was conducted to elucidate the prevalence, diagnostic measures, and impact on the clinical outcomes of DO in TOLF by integrating the existing evidence. PubMed, Embase, and Cochrane Database were comprehensively searched for studies relevant to the prevalence, diagnostic measures, or impact on the clinical outcomes of DO in TOLF. All retrieved studies meeting the inclusion and criterion were included into this systematic review. The prevalence of DO in TOLF treated surgically was 27% (281/1046), ranging from 11 to 67%. Eight diagnostic measures have been put forward to predict the DO in TOLF using the CT or MRI modalities, including "tram track sign", "comma sign", "bridge sign", "banner cloud sign", "T2 ring sign", TOLF-DO grading system, CSAOR grading system, and CCAR grading system. DO did not affect the neurological recovery of TOLF patients treated with the laminectomy. The rate of dural tear or CSF leakage in TOLF patients with DO was approximately 83% (149/180). The prevalence of DO in TOLF treated surgically was 27%. Eight diagnostic measures have been put forward to predict the DO in TOLF. DO did not affect the neurological recovery of TOLF treated with laminectomy but was associated with high risk of complications.

Schmorl's nodes are associated with prevalent osteoporotic vertebral fracture and low bone mineral density: a population-based thoracic spine MRI study in older men and women.

Schmorl's node (SN) corresponds to nucleus pulposus herniation into the vertebral spongy bone with thickened trabeculae around the formed node. We hypothesize that a pathway may exist that: osteoporosis → weakened endplate → SN development ↔ endplate fracture of an osteoporotic vertebra. For osteoporotic fractures in men (MrOS) and in women (MsOS) Hong Kong studies, at 14-year follow-up, thoracic spine magnetic resonance imaging (MRI) was sampled in 270 males (mean: 82.9±3.7 years) and 150 females (mean: 81.5±4.3 years). SN and Modic change were assessed as existed or not existed. For posterior disc protrusion, ligamentum flavum ossification, and spinal canal stenosis, semi-quantitative gradings were applied. For each vertebra in women, a score of 0, 0.5, 1, 1.5, 2, 2.5, 3 was assigned for no osteoporotic vertebral fracture (OVF) or OVF of <1/5, ≥1/5-1/4, ≥1/4-1/3, ≥1/3-2/5, ≥2/5-2/3, and ≥2/3 vertebral height loss, respectively, and a summed score was calculated by summing up the scores of vertebrae T1 to T12. For men, those of minimal grade were not considered as OVF and assigned a '0' score. SN prevalence in women (55.5%) almost doubled that in men (25.9%). SN was statistically significantly correlated with lower bone mineral density (BMD) derived femoral neck T-score, while the other four spine degeneration changes were not statistically significantly correlated with the T-score. SN were statistically significantly correlated with OVF score. Subjects with SN were more likely to have OVF, with odds ratio for men of 4.32 [95% confidence interval (CI): 1.70-11.00, P=0.002] and odds ratio for women of 3.28 (95% CI: 1.23-8.74, P=0.018). Among older population, many features of SN parallel those of OVF.

Introduction of a Novel Sequential Approach to the Ponte Osteotomy to Minimize Spinal Canal Exposure

Ponte osteotomy is an increasingly popular technique for multiplanar correction of adolescent idiopathic scoliosis. Prior cadaveric studies have suggested that sequential posterior spinal releases increase spinal flexibility. Here we introduce a novel technique involving a sequential approach to the Ponte osteotomy that minimizes spinal canal exposure. One fresh-frozen adult human cadaveric thoracic spine specimen with 4 cm of ribs was divided into three sections (T1-T5, T6-T9, T10-L1) and mounted for biomechanical testing. Each segment was loaded with five Newton meters under four conditions: baseline inferior facetectomy with supra/interspinous ligament release, superior articular process (SAP) osteotomy in situ, spinous process (SP) osteotomy in situ, and complete posterior column osteotomy with SP/SAP excision and ligamentum flavum release (PCO). Compared to baseline, in situ SAP osteotomy alone provided 3.5%, 7.6%, and 7.2% increase in flexion/extension, lateral bending, and axial rotation, respectively. In situ SP osteotomy increased flexion/extension, lateral bending, and axial rotation by 15%, 18%, and 10.3%, respectively. PCO increased flexion/extension, lateral bending, and axial rotation by 19.6%, 28.3%, and 12.2%, respectively. Our report introduces a novel approach where incremental increases in range of motion can be achieved with minimal spinal canal exposure and demonstrates feasibility in a cadaveric model.

Diagnostic value of a new axial loading MRI device in patients with suspected lumbar spinal stenosis.

This study was carried out to investigate a new device for axial loading MRI (alMRI) in the diagnosis of lumbar spinal stenosis (LSS). A total of 87 patients with suspected LSS sequentially underwent conventional MRI and alMRI using a new device with pneumatic shoulder-hip compression mode. Four quantitative parameters of dural sac cross-sectional area (DSCA), sagittal vertebral canal diameter (SVCD), disc height (DH), and ligamentum flavum thickness (LFT) at L3-4, L4-5, and L5-S1 in both examinations were measured and compared. Eight qualitative indicators were compared as valuable diagnostic information. Image quality, examinee comfort, test-retest repeatability, and observer reliability were also assessed. Using the new device, all 87 patients successfully completed alMRI with no statistically significant differences in image quality and examinee comfort from conventional MRI. Statistically significant changes were observed in DSCA, SVCD, DH, and LFT after loading (p < 0.01). SVCD, DH, LFT, and DSCA changes were all positively correlated (r = 0.80, 0.72, 0.37, p < 0.01). Eight qualitative indicators increased from 501 to 669 after axial loading, for a total increase of 168 (33.5%). Nineteen patients (21.8%, 19/87) developed absolute stenosis after axial loading and 10 of them (11.5%, 10/87) also had a significant reduction in DSCA (> 15 mm2). The test-retest repeatability and observer reliability were good to excellent. The new device is stable for performing alMRI and can exacerbate the severity of spinal stenosis, providing more valuable information for diagnosing LSS and reducing missed diagnoses. •The new axial loading MRI (alMRI) device could detect a higher frequency of patients with lumbar spinal stenosis (LSS). •The new device with pneumatic shoulder-hip compression mode was used to investigate its applicability in alMRI and diagnostic value for LSS. •The new device is stable for performing alMRI and can provide more valuable information for diagnosing LSS.

LC-MS/MS analysis of elastin crosslinker desmosines and microscopic evaluation in clinical samples of patients with hypertrophy of ligamentum flavum

Ligamentum flavum (LF) pathologies often lead to severe myelopathy or radiculopathy characterized by reduced elasticity, obvious thickening, or worsened ossification. Elastin endows critical mechanical properties to tissues and organs such as vertebrae and ligaments. Desmosine (DES) and isodesmosine (IDES) are crosslinkers of elastin monomers called tropoelastin. These crosslinkers are potential biomarkers of chronic obstructive pulmonary disease. As a biological diagnostic tool that supplements existing symptomatic, magnetic resonance imaging scanning or radiological imaging diagnostic measures for LF hypertrophy and associated pathologies, an isotope-dilution liquid chromatography-tandem mass spectrometry method with selected reaction monitoring mode for the quantitation of DESs in human plasma, urine, cerebrospinal fluid (CSF), and yellow ligamentum was investigated. Isotopically labeled IDES-13C3,15N1 was used as an internal standard (ISTD) for DES quantitation for the first time. The samples plus ISTD were hydrolyzed with 6 N hydrochloric acid. Analytes and ISTD were extracted using a solid phase extraction cellulose cartridge column. The assays were repeatable, reproducible, and accurate with % CV ≤ 7.7, ISTD area % RSD of 7.6, and % AC ≤ (101.2 ± 3.90) of the calibrations. The ligamentum samples gave the highest average DES/IDES content (2.38 μg/mg) on a dry-weight basis. A high percentage of the CSF samples showed almost no DESs. Urine and plasma samples of patients showed no significant difference from the control (p-value = 0.0519 and 0.5707, respectively). Microscopy of the yellow ligamentum samples revealed dark or blue-colored zones of elastin fibers that retained the hematoxylin dye and highly red-colored zones of collagen after counterstaining with van Gieson solution. Thus, we successfully developed a method for DES/IDES quantitation in clinical samples.

Application of unilateral biportal endoscopy technique in single-segment thoracic ossification of ligamentum flavum

To investigate the safety and effectiveness of unilateral biportal endoscopy (UBE) technique in the treatment of single-segment thoracic ossification of ligamentum flavum (TOLF). Between August 2020 and December 2021, 11 patients with single-segment TOLF were treated with UBE technique. There were 6 males and 5 females, with an average of 58.2 years (range, 49-72 years). The responsible segment was T 6, 7 in 1 case, T 7, 8 in 1 case, T 8, 9 in 2 cases, T 9, 10 in 2 cases, T 10, 11 in 2 cases, and T 11, 12 in 3 cases. Imaging examination showed that the ossification were located on the left side in 4 cases, on the right side in 3 cases, and on bilateral sides in 4 cases. The main clinical symptoms were chest and back pain or lower limb pain, all accompanied by lower limb numbness and fatigue. The disease duration ranged from 2 to 28 months (median, 17 months). The operation time, postoperative hospital stay, and complications were recorded. Visual analogue scale (VAS) score was used to evaluate the chest and back pain and low limb pain, and Oswestry disability index (ODI) and Japanese Orthopedic Association (JOA) score were used to evaluate functional recovery before operation and at 3 days, 1 month, 3 months after operation, and last follow-up. The anteroposterior diameter of the coronal spinal canal was measured by CT before and after operation to evaluate the effect of surgical decompression. All operations were successfully completed. The operation time was 50-105 minutes, with an average of 80.0 minutes. No postoperative complication such as dural sac tear, cerebrospinal fluid leakage, spinal nerve injury, or infection occurred. The postoperative hospital stay was 2-5 days, with an average of 3.1 days. All incisions healed by first intention. All patients were followed up 6-22 months, with an average of 14.8 months. CT measurement at 3 days after operation showed that the anteroposterior diameter of the spinal canal was (8.63±1.61) mm, which was significantly larger than that before operation [(3.67±1.37) mm] ( t=-12.181, P<0.001). The VAS score of chest and back pain and lower limb pain and ODI at each time point after operation were significantly lower than those before operation ( P<0.05). The above indexes were further improved after operation, except that there was no significant difference between at 3 months after operation and at last follow-up ( P>0.05), the differences between other time points were significant ( P<0.05). There was no recurrence during the follow-up period. UBE technique is a safe and effective method to treat single-segment TOLF, but its long-term effectiveness needs to be further studied.

Artificial lamina after laminectomy: Progress, applications, and future perspectives.

In clinical practice, laminectomy is a commonly used procedure for spinal decompression in patients suffering from spinal disorders such as ossification of ligamentum flavum, lumbar stenosis, severe spinal fracture, and intraspinal tumors. However, the loss of posterior column bony support, the extensive proliferation of fibroblasts and scar formation after laminectomy, and other complications (such as postoperative epidural fibrosis and iatrogenic instability) may cause new symptoms requiring revision surgery. Implantation of an artificial lamina prosthesis is one of the most important methods to avoid post-laminectomy complications. Artificial lamina is a type of synthetic lamina tissue made of various materials and shapes designed to replace the resected autologous lamina. Artificial laminae can provide a barrier between the dural sac and posterior soft tissues to prevent postoperative epidural fibrosis and paravertebral muscle compression and provide mechanical support to maintain spinal alignment. In this paper, we briefly review the complications of laminectomy and the necessity of artificial lamina, then we review various artificial laminae from clinical practice and laboratory research perspectives. Based on a combination of additive manufacturing technology and finite element analysis for spine surgery, we propose a new designing perspective of artificial lamina for potential use in clinical practice.

Effectiveness of caudal block in patients with spinal stenosis accompanied by redundant nerve root syndrome

Redundant nerve root syndrome (RNRS) is characterized by tortuous, elongated, and enlarged nerve roots in patients with lumbar spinal stenosis. This study was performed to evaluate the effects of caudal block in patients with RNRS and assess factors associated with RNRS. Patients with lumbar spinal stenosis who underwent caudal block were retrospectively analyzed. A comparative analysis of pain reduction was conducted between patients with RNRS (Group R) and those without RNRS (Group C). Generalized estimating equation analysis was used to identify factors related to the treatment response. RNRS-associated factors were analyzed using logistic regression analysis. In total, 54 patients were enrolled (Group R, n = 22; Group C, n = 32). Group R had older patients than Group C. The caudal block showed less pain reduction in Group R than in Group C, but the difference was not statistically significant. Generalized estimating equation analysis showed that RNRS was the factor significantly associated with the treatment response. The dural sac anteroposterior diameter and left ligamentum flavum thickness were associated with RNRS in the logistic regression analysis. Caudal block tended to be less effective in patients with than without RNRS, but the difference was not statistically significant.

Gebelerde Ameliyat Masasına Verilen Eğim Derecelerinin Spinal Anestezi Öncesi Yapılan Ultrasonografik Ligamentum Flavum Ölçümlerine ve Blok Başarısına Etkisi

Objective: During pregnancy, changes occur in vertebral anatomy as well as maternal physiological changes that occur in every system. The aim of this study is to compare the ligamentum flavum (LF) lengths and the success rates of spinal interventions made from the longest LF interval of pregnant women in neutral and 10° lateral tilt positions with measurements from different vertebral levels using preprocedural ultrasonography in cesarean neuraxial anesthesia. Methods: The study was carried out with 50 pregnant patients who were scheduled for cesarean section under spinal anesthesia after the approval of the local ethics committee. The patient was seated sideways with her feet hanging down. When the lateral tilt angle of the table is 0° and 10° measurements were made at L3-L4 and L4-L5 levels. Ligamentum flavum, skin-LF distance and interlaminar space were measured. Afterwards, spinal anesthesia was performed at the longest measurement level of LF and at the table angle. Results: At the L3-L4 and L4-L5 levels, LF lengths at 0° table tilt were compared with the LF lengths at 10° lateral tilt position, a significant increase was observed at 10° (p=0.001, p=0.001). According to the condition of applying spinal anesthesia from the angle and interval where the LF is the longest in the study; 54% of the procedures were performed in the L3-L4 level 10° lateral tilt position and 46% of the procedures were performed in the L4-L5 level 10° lateral tilt position. In the 10° lateral tilt position, there was no difference between the L3-L4 and L4-L5 intervals between the number of trials and needle guidance. Conclusion: As a result, using preprocedural vertebral ultrasound and 10° lateral tilt in neuraxial procedures in pregnant women will allow to easily determine the longest interval of LF and to perform successful neuraxial anesthesia with the least number of attempts. Keywords: Anesthesia spinal, pregnancy, ligamentum flavum, neuraxial, ultrasonography

Relative risk factors of nerve root sedimentation sign (SedSign) in patients with severe central lumbar spinal stenosis (LSS)

The incidence of nerve root sedimentation sign (SedSign) was evaluated to explore potential pathogenesis in patients with severe lumbar spinal stenosis (LSS). In a total of 209 patients with severe LSS, 290 intervertebral levels were narrow, among which 248 showed a positive SedSign, giving a prevalence of 85.52%. Those levels with a positive SedSign were further analyzed relative to those with a negative SedSign. There was no significant difference between the two groups for the cross-sectional area (CSA) or the posteroanterior diameter (PAD). In contrast, there was a significant difference between the groups for the grade of degenerative facet joint (DFJ) (p < 0.05), the thickness of ligamentum flavum (TLF) (p < 0.01), and the cross-sectional area difference (CSAD) (p < 0.01). In addition, receiver operating characteristic (ROC) curves were used to identify associated factors. The area under the ROC curve for PAD was 0.608 (p < 0.05), for DFJ was 0.634 (p < 0.05), for TLF was 0.74 (p < 0.01), and for CSAD was 0.911 (p < 0.01). In summary, a positive SedSign has notable advantages in assisting with the diagnosis of severe LSS. Compression of the dural sac from the rear may be the main risk factors of a positive SedSign.

Novel therapeutic strategy in the treatment of ossification of the ligamentum flavum associated with dural ossification.

To investigate the imaging characteristics of thoracic ossification of ligamentum flavum (OLF) combined with dural ossification (DO) and the clinical efficacy of zoning laminectomy. The clinical data of 48 patients with thoracic OLF combined with DO who underwent zoning laminectomy between June 2016 and May 2020 were retrospectively analyzed. The modified Japanese Orthopedic Association (mJOA) score was used to evaluate neurological function before and after surgery, and the clinical efficacy was evaluated according to the improvement rate. The symptoms of all patients significantly improved after the operation, and the average follow-up time was 27.8 (10-47) months. In addition, the average mJOA score had increased from 5.0 (2-8) preoperatively to 8.7 (6-11) postoperatively (t = 18.880, P < 0.05). The average improvement rate was 62.6% (25-100%), with 16 patients graded as excellent, 21 as good, and 11 as fair. Cerebrospinal fluid leakage occurred in 12 cases (25.0%), and all of them healed well after treatment. No postoperative aggravation of neurological dysfunction, wound infection or hematoma occurred. At the last follow-up, there was no recurrence of symptoms and kyphosis. The Zoning laminectomy described here is both safe and effective.

The midline interlaminar ligament of the spine: An anatomical study.

During routine cadaveric dissection, Simonds et al. in 2019 found a previously undocumented ligament, which they termed the midline interlaminar ligament (MIL), in 24 out of 36 (76.5%) lumbar spinal levels. The MIL is an unpaired ligament located between and distinctly separate from the right and left ligamenta flava (LF). The purpose of this study was to identify the presence or absence of the MIL in the cervical, thoracic, and lumbar spinal regions and obtain detailed measurements of the ligaments' toughness (R) and elastic modulus (E). Intact preserved cadaveric vertebrae from C2 to the upper sacral region were dissected. Presence or absence of the MIL was documented, and length and width of each MIL were measured in situ. The R and E of the LFs from corresponding spinal segments were found for comparison. At least one MIL was observed in 90.3% (28) of specimens. Eighty-eight MIL's were observed out of 186 cervical intervertebral levels (0.5%), 371 thoracic intervertebral levels (5.9%), and 101 lumbar intervertebral levels (63.4%). The mean width and length of the MIL were 1.21 ± 0.36 and 16.37 ± 2.17 mm, respectively. The mean R of the MIL and the LF were 1390.27 and 2068.04 J m-2 , respectively. The mean E of the MILs and LFs was 46.78 ± 16.65 and 51.15 ± 21.68 MPa, respectively. Based on our findings, the MIL was present in the majority of vertebrae in our cadaveric population with a predominance for the lumbar region.

Full-Endoscopic Decompression for Thoracic Ossification of the Ligamentum Flavum Combined with Dural Ossification

Ossification of the ligamentum flavum (OLF) can result in spinal stenosis. Thoracic spinal cord compression due to spinal stenosis is a common cause of progressive thoracic myelopathy in Asian countries. The incidence of complications is high in open decompression surgeries for thoracic OLF. With dural ossification (DO), the risk of complications is even higher in thoracic OLF. We introduce a full-endoscopic decompression surgery for thoracic OLF combined with DO under local anesthesia. Hemilaminectomy is performed using a high-speed burr under the endoscopy first, and then decompression of the contralateral spinal canal is completed using an "over the top" technique. DO resection uses the eggshell technique; after the base of the DO is cut from the lamina, forceps or lamina rongeurs are typically used for removal. The dural defect left after resection does not need repair. Neurological function was improved, and no complications such as hematoma or neck pain occurred. On imaging, no pseudodural cyst, cerebrospinal fluid leakage, or wound complications were observed after the operation. Endoscopic surgery causes less damage to the posterior ligament complex, so no cases of persistent back pain complaints or secondary internal fixation requirements were found in this study. Full-endoscopic decompression can achieve good imaging and clinical effects in the treatment of thoracic OLF with DO.

Potential Involvement of Oxidative Stress in Ligamentum Flavum Hypertrophy.

Oxidative stress (OS) results in many disorders, of which degenerative musculoskeletal conditions are no exception. However, the interaction between OS and ligamentum flavum (LF) hypertrophy in lumbar spinal canal stenosis is not clearly understood. The first research question was whether OS was involved in LF hypertrophy, and the second was whether the antioxidant N-acetylcysteine (NAC) was effective on LF hypertrophy. In total, 47 LF samples were collected from patients with lumbar spinal disorders. The cross-sectional area of LF was measured on axial magnetic resonance imaging. Immunohistochemistry of 8-OHdG and TNF-α were conducted on human LF samples. A positive association was found between 8-OHdG or TNF-α expression and cross-sectional area of LF. Flow cytometry analysis showed that H2O2, buthionine sulfoximine, and TNF-α treatment significantly increased intracellular reactive oxygen species in primary LF cells. NAC inhibited the induction of LF hypertrophy markers by OS or TNF in a real-time reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Western blotting analysis indicated that p38, Erk, and p65 phosphorylation were involved in intracellular OS signaling in LF cells. In conclusion, our results indicated that OS could be a therapeutic target for LF hypertrophy. Although this study included no in vivo studies to examine the longitudinal efficacy of NAC on LF hypertrophy, NAC may have potential as a therapeutic agent against lumbar spinal canal stenosis.