Short-term lumbar disc and lumbar stability changes of one-hole split endoscope technique treatment of spinal stenosis.

OBJECTIVE: Investigating the early biomechanical effects of the one-hole split endoscope (OSE) technique on lumbar spine after decompression surgery. METHODS: A retrospective analysis was conducted on 66 patients with lumbar spinal stenosis (LSS) who underwent OSE technique surgery at the affiliated hospital of Binzhou Medical University from September 2021 to September 2022. The patients had complete postoperative follow-up records. The mean age was (51.73 ± 12.42) years, including 33 males and 33 females. The preoperative and postoperative imaging data were analyzed, including disc height (DH), foraminal height (FH), lumbar lordosis angle (LLA), changes in disc angle, anterior-posterior translation distance, and lumbar intervertebral disc Pfirrmann grading. The visual analogue scale (VAS) was applied to evaluate the severity of preoperative, postoperative day 1, postoperative 3 months, and final follow-up for back and leg pain. The Oswestry Disability Index (ODI) was applied to assess the functionality at all the listed time points. The modified MacNab criteria were applied to evaluate the clinical efficacy at the final follow-up. RESULTS: In 66 patients, there were statistically significant differences (p < 0.05) in DH and FH at the affected segments compared to preoperative values, whereas no significant differences (p > 0.05) were found in DH and FH at the adjacent upper segments compared to preoperative values. There was no statistically significant difference in the LLA compared to preoperative values (p > 0.05). Both the affected segments and adjacent upper segments showed statistically significant differences in Pfirrmann grading compared to preoperative values (p < 0.05). There were no statistically significant differences in the changes in disc angle or anterior-posterior translation distance in the affected or adjacent segments compared to preoperative values (p > 0.05). The VAS scores for back and leg pain, as well as the ODI, significantly improved at all postoperative time points compared to preoperative values. Among the comparisons at different time points, the differences were statistically significant (p < 0.05). The clinical efficacy was evaluated at the final follow-up using the modified MacNab criteria, with 51 cases rated as excellent, 8 cases as good, and 7 cases as fair, resulting in an excellent-good rate of 89.39%. CONCLUSIONS: The OSE technique, as a surgical option for decompression in the treatment of LSS, has no significant impact on lumbar spine stability in the early postoperative period. However, it does have some effects on the lumbar intervertebral discs, which may lead to a certain degree of degeneration.

Biochemical changes in lumbar facet joint and disc degeneration by T2* mapping.

BACKGROUND: To investigate the biochemical changes in lumbar facet joint (LFJ) and intervertebral disc (IVD) with different degenerative grade by T2* mapping. METHODS: Sixty-eight patients with low back pain (study group) and 20 volunteers (control group) underwent standard MRI protocols and axial T2* mapping. Morphological evaluation of LFJ and IVD were performed on T2-weighted imaging according to Weishaupt and Pfirrmann grading system, respectively. T2* values of LFJ and of AF (anterior annulus fibrosus), NP (nucleus pulposus), and PF (posterior annulus fibrosus) in IVD were measured. Kruskal-Wallis test and Wilcoxon rank-sum test were used to compare T2* values of subjects with different degenerative grade. RESULTS: The mean T2* value of grade 0 LFJ (21.68[17.77,26.13]) was higher than those of grade I (18.42[15.68,21.8], p < 0.001), grade II (18.98[15.56,22.76], p = 0.011) and grade III (18.38[16.05,25.07], p = 0.575) LFJ in study group, and a moderate correlation was observed between T2* value and LFJ grade (rho=-0.304, p < 0.001) in control group. In the analysis of IVD, a moderate correlation was observed between AF T2* value and IVD grade (rho=-0.323, p < 0.001), and between NP T2* value and IVD grade (rho=-0.328, p < 0.001), while no significant difference was observed between the T2* values of PF in IVD of different grade in study group. CONCLUSIONS: Downward trend of T2* values can be found in LFJ, AF and NP as the degenerative grade rised. But in elderly patients with low back pain, no change trend was found in LFJ due to increased fluid accumulation in the joint space.

IVD fibrosis and disc collapse comprehensively aggravate vertebral body disuse osteoporosis and zygapophyseal joint osteoarthritis by posteriorly shifting the load transmission pattern.

BACKGROUND: Disuse is a typical phenotype of osteoporosis, but the underlying mechanism has yet to be identified in elderly patients. Disc collapse and intervertebral disc (IVD) fibrosis are two main pathological changes in IVD degeneration (IDD) progression, given that these changes affect load transmission patterns, which may lead to disuse osteoporosis of vertebral bodies and zygapophyseal joint (ZJ) osteoarthritis (ZJOA) biomechanically. METHODS: Clinical data from 59 patients were collected retrospectively. Patient vertebral bony density, ZJOA grade, and disc collapse status were judged via CT. The IVD fibrosis grade was determined based on the FA measurements. Regression analyses identified potential independent risk factors for osteoporosis and ZJOA. L4-L5 numerical models with and without disc collapse and IVD fibrosis were constructed; stress distributions on the bony endplate (BEP) and zygapophyseal joint (ZJ) cartilages were computed in models with and without disc collapse and IVD fibrosis. RESULTS: A significantly lower disc height ratio and significantly greater FA were recorded in patients with ZJOA. A significant correlation was observed between lower HU values and two parameters related to IDD progression. These factors were also proven to be independent risk factors for both osteoporosis and ZJOA. Correspondingly, compared to the intact model without IDD. Lower stress on vertebral bodies and greater stress on ZJOA can be simultaneously recorded in models of disc collapse and IVD fibrosis. CONCLUSIONS: IVD fibrosis and disc collapse simultaneously aggravate vertebral body disuse osteoporosis and ZJOA by posteriorly shifting the load transmission pattern.

Reconsidering high intensity zones: its role in intervertebral disk degeneration and low back pain.

PURPOSE: High intensity zones (HIZ) in the lumbar intervertebral disk (IVD) can be associated with degenerative changes which may ultimately manifest as low back pain (LBP). However, the relationship between the prevalence of HIZ and lumbar degenerative parameters is still unclear. The purpose of this study was to determine the prevalence of HIZ in the lumbar spine, analyze the independent relationship between HIZ and lumbar degenerative parameters measured on MRI and X-ray and determine the association between HIZ and the presence of LBP. METHODS: A retrospective review of MRI data, X-ray data, and radiology reports for 136 consecutively recruited patients, above 18-years-age and with both lumbar MRI and X-ray scans was conducted. 57 patients with HIZ were identified. Patients without HIZ (n = 79) made up the control group. RESULTS: HIZ was prevalent in 41.9% of patients and in 11.0% of all lumbar IVDs. The odds of developing HIZ were 6.4 (Exp(B) 6.4, 95%CI [3.157-12.988]) and 3.0 (Exp(B) 3.0, 95%CI [1.603, 5.674]) times higher in IVDs with disk bulge/protrusion and nucleus degeneration, respectively. Odds of HIZ was also increased in disks with larger IVD angle (Exp(B) 1.1, 95%CI [1.034, 1.169]). The odds of patients presenting to imaging with LBP was 3.0 (OR 3.0, 95%CI [1.478-6.338]) times higher in the HIZ compared to the control group. CONCLUSIONS: HIZ was prevalent in 41.9% of participants that were recruited in this study. Nucleus degeneration, disk bulge/protrusion and increased IVD angle were found to be independently associated with HIZ and since there is an increased likelihood of LBP, we posit that HIZ is likely a symptomatic and clinically meaningful diagnostic tool in the assessment of LBP.

A rare case of intervertebral disc calcification combined with ossification of the posterior longitudinal ligament in a child: a case report and literature review.

BACKGROUND: Intervertebral disc calcification (IDC) combined with calcification in children has been sporadically reported, while ossification of the posterior longitudinal ligament (OPLL) in the cervical spine in pediatric patients is exceedingly rare. The aim of this study is to investigate the potential prognosis and outcomes associated with this condition. CASE PRESENTATION: We present an unusual case involving a 10-year-old Chinese child diagnosed with calcified cervical disc herniation and ossification of the posterior longitudinal ligament. Conservative treatment measures were implemented, and at the 1-month and 6-month follow-up, the patient's pain exhibited significant improvement. Subsequent cervical MRI and CT scans revealed the complete disappearance of OPLL and substantial absorption of the calcified disc. During the three-month follow-up, CT demonstrated slight residual disc calcification, however, the patient remained asymptomatic with no discernible limitation in cervical motion. CONCLUSIONS: We conducted a comprehensive review of several cases presenting with the same diagnosis. It is noteworthy that IDC combined with OPLL in children constitutes a rare clinical entity. Despite imaging indications of potential spinal canal occupation, the majority of such cases demonstrate complete absorption following conservative treatment, with OPLL exhibiting a faster absorption rate than calcified discs.

Biomechanical Analysis of Adjacent Segments after Spinal Fusion Surgery Using a Geometrically Parametric Patient-Specific Finite Element Model.

This study aimed to perform a mechanical analysis of adjacent segments after spinal fusion surgery using a geometrically parametric patient-specific finite element model to elucidate the mechanism of adjacent segment degeneration (ASD), thereby providing theoretical evidence for early disease prevention. Fourteen parameters based on patient-specific spinal geometry were extracted from a patient's preoperative computed tomography (CT) scan, and the relative positions of each spinal segment were determined using the image match method. A preoperative patient-specific model of the spine was established through the above method. The postoperative model after L4-L5 posterior lumbar interbody fusion (PLIF) surgery was constructed using the same method except that the lamina and intervertebral disc were removed, and a cage, 4 pedicle screws, and 2 connecting rods were inserted. Range of motion (ROM) and stress changes were determined by comparing the values of each anatomical structure between the preoperative and postoperative models. The overall ROM of the lumbar spine decreased after fusion, while the ROM, stress in the facet joints, and stress in the intervertebral disc of adjacent segments all increased. An analysis of the stress distribution in the annulus fibrosus, nucleus pulposus, and facet joints also showed that not only was the maximum stress in these tissues elevated, but the areas of moderate-to-high stress were also expanded. During torsion, the stress in the facet joints and annulus fibrosus of the proximal adjacent segment (L3-L4) increased to a larger extent than that in the distal adjacent segment (L5-S1). While fusion surgery causes an overall restriction of motion in the lumbar spine, it also causes more load sharing by the adjacent segments to compensate for the fused segment, thus increasing the risk of ASD. The proximal adjacent segment is more prone to degeneration than the distal adjacent segment after spinal fusion due to the significant increase in stress.

An in Vivo, Three-Dimensional (3D), Functional Centers of Rotation of the Healthy Cervical Spine.

OBJECTIVE: This study examined cervical center of rotation (COR) positions in 7 postures using validated cone beam computed tomography (CBCT) combined with 3D-3D registration in healthy volunteers. METHODS: CBCT scans were performed on 20 healthy volunteers in 7 functional positions, constructing a three-dimensional (3D) model. Images were registered to the neutral position using 3D-3D registration, allowing analysis of kinematic differences and rotational axes. COR measurements were obtained for each segment (C2/3 to C6/7) in each posture. RESULTS: The CORs of C2/3 to C6/7 were predominantly posterior (-5.3 ± 3.8 ∼ -0.6 ± 1.2 mm) and superior (16.5 ± 6.0 ∼ 23.6 ± 3.2 mm) to the intervertebral disc's geometric center (GC) in flexion and extension. However, the C4/5 segment's COR was anterior to the GC (2.0 ± 9.8 mm) during flexion and close to it in the right-left direction. During left-right twisting, the CORs of C2/3-C6/7 were posterior (-21.8 ± 10.5 ∼-0.9 ± 0.8 mm) and superior (3.1 ± 7.5 ∼23.2 ± 3.6 mm) to the GCs in anterior-posterior and superior-inferior directions, without consistent right-left directionality. During left-right bending, each segment's COR was predominantly posterior (-25.2 ± 13.1 ∼-6.5 ± 9.9 mm) and superior (0.3 ± 12.5 ∼12.1 ± 5.1 mm) to the GC in anterior-posterior and superior-inferior directions, except for the C2/3 segment, located inferiorly (-5.9 ± 4.1 mm) in left bending. The right-left COR position varied across segments. CONCLUSIONS: Our findings reveal segment-specific and posture-dependent COR variations. Notably, the CORs of C3/4, C4/5, and C5/6 consistently align near the intervertebral disc's GC at different postures, supporting their suitability for total disc replacement surgery within the C3/4 to C5/6 segments.

The influence of geometry on intervertebral disc stiffness.

Geometry plays an important role in intervertebral disc (IVD) mechanics. Previous computational studies have found a link between IVD geometry and stiffness. However, few experimental studies have investigated this link, possibly due to difficulties in non-destructively quantifying internal geometric features. Recent advances in ultra-high resolution MRI provides the opportunity to visualise IVD features in unprecedented detail. This study aimed to quantify 3D human IVD geometries using 9.4 T MRIs and to investigate correlations between geometric variations and IVD stiffness. Thirty human lumbar motion segments (fourteen non-degenerate and sixteen degenerate) were scanned using a 9.4 T MRI and geometric parameters were measured. A 1kN compressive load was applied to each motion segment and stiffness was calculated. Degeneration caused a reduction (p < 0.05) in IVD height, a decreased nucleus-annulus area ratio, and a 1.6 ± 3.0 mm inward collapse of the inner annulus. The IVD height, anteroposterior (AP) width, lateral width, cross-sectional area, nucleus-annulus boundary curvature, and nucleus-annulus area ratio had a significant (p < 0.05) influence on IVD stiffness. Linear relationships (p < 0.05, r > 0.47) were observed between these geometric features and IVD compressive stiffness and a multivariate regression model was generated to enable stiffness to be predicted from features observable on clinical imaging (stiffness, N/mm = 6062 - (61.2 × AP width, mm) - (169.2 × IVD height, mm)). This study advances our understanding of disc structure-function relationships and how these change with degeneration, which can be used to both generate and validate more realistic computational models.

Induction of cervical disc degeneration and discogenic pain by low concentration Propionibacterium acnes infection: an in vivo animal study.

BACKGROUND: Although cervical intervertebral disc (IVD) degeneration is closely associated with neck pain, its cause remains unclear. In this study, an animal model of cervical disc degeneration and discogenic neck pain induced by a low concentration of Propionibacterium acnes (P. acnes-L) is investigated to explore the possible mechanisms of cervical discogenic pain. METHODS: Cervical IVD degeneration and discitis was induced in 8-week-old male rats in C3-C6 IVDs through the anterior intervertebral puncture with intradiscal injections of low and high concentrations of P. acnes (P. acnes-L, n = 20 and P. acnes-H, n = 15) or Staphylococcus aureus (S. aureus, n = 15), compared to control (injection with PBS, n = 20). The structural changes in the cervical IVD using micro-CT, histological evaluation, and gene expression assays after MRI scans at 2 and 6 weeks post-modeling. The P. acnes-L induced IVD degeneration model was assessed for cervical spine MRI, histological degeneration, pain-like behaviors (guarding behavior and forepaw von Frey), nerve fiber growth in the IVD endplate region, and DRG TNF-α and CGRP. RESULTS: IVD injection with P. acnes-L induced IVD degeneration with decreased IVD height and MRI T2 values. IVD injection with P. acnes-H and S. aureus both lead to discitis-like changes on T2-weighted MRI, trabecular bone remodeling on micro-CT, and osseous fusion after damage in the cartilage endplate adjacent to the injected IVD. Eventually, rats in the P. acnes-L group exhibited significant nociceptive hypersensitivity, nerve fiber ingrowth was observed in the IVD endplate region, inflammatory activity in the DRG was significantly increased compared to the control group, and the expression of the pain neurotransmitter CGRP was significantly upregulated. CONCLUSION: P. acnes-L was validated to induce cervical IVD degeneration and discogenic pain phenotype, while P. acnes-H induced was identified to resemble septic discitis comparable to those caused by S. aureus infection.

Imaging of Discogenic and Vertebrogenic Pain.

Chronic low back pain is a major source of pain and disability globally involving multifactorial causes. Historically, intervertebral disc degeneration and disruption have been associated as primary back pain triggers of the anterior column, termed "discogenic pain." Recently, the vertebral endplates have been identified as another possible pain trigger of the anterior column. This "endplate-driven" model, defined "vertebrogenic pain," is often interconnected with disc degeneration. Diagnosis of vertebrogenic and discogenic pain relies on imaging techniques that isolate pain generators and exclude comorbid conditions. Traditional methods, like radiographs and discography, are augmented by more sensitive methods, including SPECT, CT, and MRI. Morphologic MRI is pivotal in revealing indicators of vertebrogenic (eg, Modic endplate changes) and discogenic pain (eg, disc degeneration and annular fissures). More advanced methods, like ultra-short-echo time imaging, and quantitative MRI further amplify MRI's accuracy in the detection of painful endplate and disc pathology. This review explores the pathophysiology of vertebrogenic and discogenic pain as well as the impact of different imaging modalities in the diagnosis of low back pain. We hope this information can help identify patients who may benefit from personalized clinical treatment and image-guided therapies.

Lumbar Disc Degeneration Is Linked to Dorsal Subcutaneous Fat Thickness at the L1-L2 Intervertebral Disc Level Measured by MRI.

BACKGROUND: Obese individuals have a higher risk of degenerative disc disease (DDD). Currently, body mass index is not sensitive enough to differentiate between muscle and fat distribution, and obesity-related health issues are linked to the way body fat is distributed. Therefore, this study aims to investigate the association between the dorsal subcutaneous fat thickness (DSFT) of the lumbar spine, an alternative measurement tool of body fat distribution, and DDD. METHODS: A total of 301 patients with DDD and 123 participants without the disease were recruited. Using length functions of magnetic resonance imaging (MRI) console, the DSFT of L1 to S1 intervertebral disc levels was measured in mid-sagittal spin-echo T2 weighted image. The Mann-Whitney U test and Chi-squared test (X2) were utilized to examine any variations between the case and control groups. Logistic regression models were built to explore the association of the DSFT with DDD. RESULTS: The logistical regression model showed a positive association between DDD and DSFT [OR: 1.30, 95% CI: 1.02-1.64, p = 0.03]. In the stratified logistic regression analysis, a positive association was found between DDD and DSFT among younger participants and females [OR young: 1.48; 95% CI (1.02-2.20); p = 0.04-OR female: 1.37; 95% CI (1-1.88); p = 0.05]. CONCLUSIONS: Younger females with thicker DSFT at the L1-L2 level are more likely to develop DDD. This suggests that increased DSFT may be a contributing factor to DDD.

Adjacent segment degeneration after single- and double-level cervical total disc replacement: a cohort with an over 12-year follow-up.

PURPOSE: To characterize the change of adjacent segment degeneration (ASD) after cervical total disc replacement (CTDR) with more than 12-year follow-up, and identify the risk factors for ASD. METHOD: This process included 75 patients underwent CTDR from February 2004 to December 2012, with the follow-up of 151.9 ± 36.0 (m). The artificial disc included ProDisc-C, Prestige-LP and Mobi-C. ASD was followed up at 1 week, 6 months, 1 year, 2 years, 5 years, 10 years after CTDR and at the endpoint of June 2022. The radiographic measurements were cervical mobility, intervertebral disc height (IDH), cervical lordosis and balance status. The complications were implant migration, subsidence and heterotopic ossification (HO). RESULTS: Cervical mobility in adjacent segments, IDH and lordosis showed no statistical differences between ASD and NASD group. Balance status, subsidence and migration showed no relationship with ASD. Postoperative ASD increased at 6 m and especially between 6 m to 2y. There was no difference between the incidence of upper ASD and lower ASD all the time and few ASD-related reoperation. The majority of adjacent segments were C4/5 (33.6%) and C6/7 (34.2%), and ASD of C5/6 had the highest incidence (61.5%). Cox regression showed ASD was not related to the types of prosthesis or operated numbers. Generalized estimating equations (GEE) analysis showed severe HO had a higher (2.68 times) probability to suffer from ASD. CONCLUSIONS: After over 12-year follow-up of CTDR, the occurrence of ASD and HO had temporal synchronization. ASD was not merely a natural progression but with the pathological process such as HO.

The Relationship Between Endplate Defect Scores and Lumbar Sagittal Translation Stability in Lumbar Spondylolisthesis Patients.

BACKGROUND: Lumbar instability and endplate defects are commonly seen in patients with spondylolisthesis. However, little is known about associations between segmental stability and endplate defects. The present study explored associations between stability-related radiographic parameters and endplate defect scores and assessed whether endplate defect scores can predict lumbar stability in lumbar spondylolisthesis. METHODS: Neutral, flexion, and extension radiographs of 159 patients with monosegmental lumbar spondylolisthesis were analyzed. Radiographic parameters included average intervertebral disc height (IDH), slip distance, sagittal translation (ST) and sagittal angulation (SA). Correlation analysis and linear regression analysis were used to explore associations between endplate defect scores and radiographic parameters. Logistic regression analysis was used to assess associations between endplate defect scores and ST stability. Receiver-operating characteristic curve (ROC) analysis was used to evaluate the value of the endplate defect score in predicting ST stability. RESULTS: A total of 11.9% of patients had ST ≥ 4 mm, and 30% of patients had SA ≥ 10°. Endplate defect scores were negatively correlated with ST and IDH and positively correlated with slip distance in isthmic spondylolisthesis but not in degenerative spondylolisthesis. In multiple regression analysis, endplate defect scores were significantly associated with ST, slip distance, IDH, and disc degeneration. ST instability was associated with endplate defect scores in isthmic spondylolisthesis (OR=0.460, P = 0.010). The AUCs for using the endplate defect score to evaluate ST stability in overall patients and isthmic spondylolisthesis patients were 0.672 and 0.774, respectively. The optimal threshold of the endplate defect score constructed by the Youden index was 7.5 for predicting ST stability. CONCLUSIONS: Endplate defect scores increase with a reduction in IDH, progression of slippage and a decrease in ST in isthmic spondylolisthesis but not in degenerative spondylolisthesis. ST instability was associated with endplate defect scores in isthmic spondylolisthesis, and endplate defect scores could be used to reflect lumbar stability at the slippage segment.

Novel Modic grading scoring system and its clinical validation: a preliminary investigation.

PURPOSE: To propose a novel Modic grading scoring system and explore the relationship between the Modic grading score and disc degeneration, disc herniation, disc height, and clinical symptom scores. METHOD: In total, 194 patients were included in the study. The new Modic grading scoring system included four indicators: invaded vertebral height, invaded endplate length, endplate morphology, and grade of endplate defects. The severity of Modic changes was visually quantified by numerical scores, and the kappa value was used to verify the interobserver and intraobserver reliability. Spearman correlation analysis was used to explore the relationship between the Modic grading score and intervertebral disc degeneration, disc herniation, disc height, and clinical symptom scores. RESULTS: The interobserver and intraobserver reliability showed substantial to almost perfect agreement in the new Modic grading scoring system. The Modic grading score was positively correlated with intervertebral disc degeneration (r = 0.757, p < 0.001) and negatively correlated with the intervertebral disc height index (r = - 0.231, p < 0.001). There was no significant correlation between the Modic grading scoring system and disc herniation (r = 0.369, p = 0.249). Additionally, there was no significant correlation between the Modic grading score and the Japanese Orthopaedic Association score (r = - 0.349, p = 0.25), Oswestry Disability Index score (r = 0.246, p = 0.11), or visual analogue scale score (r = 0.315, p = 0.35). CONCLUSION: The new Modic grading scoring system had good interobserver and intraobserver reliability. The Modic grading score was positively correlated with intervertebral disc degeneration and negatively correlated with the intervertebral disc height.

Comparison of three methods for nucleus pulposus volume measurement in rabbit lumbar spines: a preclinical model for measurement of the effectiveness of prophylactic intervertebral disk fenestration in dogs.

OBJECTIVE: Compare 3 methods of nucleus pulposus (NP) volume measurement using the rabbit lumbar spines as a preclinical model to determine the effectiveness of prophylactic intervertebral disk fenestration in dogs. ANIMALS: Twelve 9-month-old, skeletally mature female entire New Zealand White rabbits weighing between 3.5 to 4.5 kg. METHODS: NP volume measurements of dissected rabbit lumber spines between L1 and L6 were made and compared using gross measurements, reconstructed MRI images, and water volumetry based on Archimedes' principle. Water volumetry was used as the true gold standard volume measurement in this study. RESULTS: The true volume (mean ± SD) of the nucleus pulposus NP as measured by water volumetry increased caudally from L1/L2 (16.26 ± 3.32 mm3) to L5/L6 (22.73 ± 6.09 mm3). Volume estimates made by MRI were significantly higher than those made using water volumetry at all sites (L1/L2 [P = .044], L2/L3 [P = .012], L3/L4 [P = .015], L4/L5 [P < .001], and L5/L6 [P < .001]). Gross measurements also significantly overestimated volume when compared to water volumetry at all sites; L1/L2 (P = .021), L2/L3 (P = .025), L3/L4 (P = .001), L4/L5 (P < .001), and L5/L6 (P < .001). MRI and gross volume estimates were significantly different at L4/L5 (P = .035) and L5/L6 (P = .030). CLINICAL RELEVANCE: The findings of this preclinical model might be relevant to veterinary surgeons who perform prophylactic fenestration for which there is no reliable method to determine the amount of NP to be removed. Preclinical ex vivo and in vivo fenestration studies with pre- and postoperative NP volume assessment are required.

Potential Use of Extracellular Vesicles in the Treatment of Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IVDD) is a major cause of low back pain, and several studies have evaluated the efficacy of extracellular vesicles (EVs) in the treatment of IVDD. The databases PubMed, Embase, and Cochrane Library were systematically searched from inception to the end of 2022 to identify studies investigating the therapeutic potential of cell-derived EVs for IVDD treatment. The following outcome measures were utilized: magnetic resonance imaging (MRI) Pfirrmann grading system, disc height index (DHI), histological grading, and apoptosis rate. A comprehensive meta-analysis was conducted, including a total of 13 articles comprising 19 studies involving 218 experimental animals. Comparative analysis between normal cell-derived EVs and placebo revealed significant reductions in MRI grade, increased DHI values, decreased nucleus pulposus cell apoptosis rates, and improved tissue grades. These findings collectively demonstrate the effective inhibition of IVDD through the application of EVs derived from cells. In conclusion, this study provides an updated synthesis of evidence supporting the efficacy of EVs as a promising therapeutic approach for IVDD treatment.

Morphological alterations of lumbar intervertebral discs in patients with adolescent idiopathic scoliosis.

BACKGROUND CONTEXT: Etiology of adolescent idiopathic scoliosis (AIS) is still unknown. Prior in vitro research suggests intervertebral disc pathomorphology as a cause for the initiation and progression of the spinal deformity, however, this has not been well characterized in vivo. PURPOSE: To quantify and compare lumbar disc health and morphology in AIS to controls. STUDY DESIGN/SETTING: Cross-sectional study. METHODS: All lumbar discs were imaged using a 3T MRI scanner. T2-weighted and quantitative T2* maps were acquired. Axial slices of each disc were reconstructed, and customized scripts were used to extract outcome measurements: Nucleus pulposus (NP) signal intensity and location, disc signal volume, transition zone slope, and asymmetry index. Pearson's correlation analysis was performed between the NP location and disc wedge angle for AIS patients. ANOVAs were utilized to elucidate differences in disc health and morphology metrics between AIS patients and healthy controls. α=0.05. RESULTS: There were no significant differences in disc health metrics between controls and scoliotic discs. There was a significant shift in the NP location towards the convex side of the disc in AIS patients compared to healthy controls, with an associated increase of the transition zone slope on the convex side. Additionally, with increasing disc wedge angle, the NP center migrated towards the convex side of the disc. CONCLUSIONS: The present study elucidates morphological distinctions of intervertebral discs between healthy adolescents and those diagnosed with AIS. Discs in patients diagnosed with AIS are asymmetric, with the NP shifted towards the convex side, which was exacerbated by an increased disc wedge angle. CLINICAL SIGNIFICANCE: Investigation of the MRI signal distribution (T2w and T2* maps) within the disc suggests an asymmetric pressure gradient shifting the NP laterally towards the convexity. Quantifying the progression of these morphological alterations during maturation and in response to treatment will provide further insight into the mechanisms of curve progression and correction, respectively.

Hydrogel Augmentation of the Lumbar Intervertebral Disc: An Early Feasibility Study of a Treatment for Discogenic Low Back Pain.

PURPOSE: To assess the safety and effectiveness of intradiscal hydrogel in patients with chronic low back pain (CLBP) due to degenerative disc disease (DDD) refractory to conventional medical management. MATERIALS AND METHODS: Twenty patients aged 22-69 years with numerical rating scale (NRS) pain of ≥4 were enrolled. All patients with CLBP resulting from DDD confirmed by imaging and discography received injections of hydrogel (Hydrafil Intervertebral Disc Augmentation; ReGelTec, Baltimore, Maryland) at 1 or 2 lumbar levels (29 levels treated) from August to December 2020. The primary safety end point was freedom from serious adverse events (SAEs). The primary performance end point was successful gel delivery into the desired disc. Patients were also assessed on the NRS as well as the Oswestry disability index (ODI). RESULTS: Nineteen patients were followed up at a mean of 131 days, and 1 patient was lost to follow-up. Preliminary results showed significant reductions in median NRS back pain from 7 (range 4-10) to 1 (range 0-8) (P <.0001) and median ODI scores from 54 (range 22-58) to 2 (range 0-58) (P <.0001) at 6 months of follow-up. There were 5 SAEs, and 4 of the 2 were determined to be associated with treatment. CONCLUSIONS: This early feasibility study showed that the hydrogel implant was safe with no persistently symptomatic SAEs, and demonstrated effectiveness with significant reduction in pain and improvement in function when used to treat painful DDD and CLBP.

Tissue Identification of Intervertebral Disc Anatomy Using Forward-oriented Ultrasound Endoscopic System: A Feasibility Study.

Minimally invasive surgery is widely used for spine surgery, however the commonly used optical endoscopes cannot identity tissues under surface. In this study, a forward-oriented ultrasound endoscopic system was proposed to detect and identity different types of tissues for surgical approaches. A total of 150 ultrasound image data were collected from 6 types of intervertebral disc tissue using a custom-developed endoscopic probe. The gray-level co-occurrence matrix (GLCM) properties including energy (angular second moment, ASM), contrast, entropy, and homogeneity (inverse difference moment, IDM) were calculated on the acquired ultrasound images, and the single-parameter and combined parameter were applied for tissue classification. The classification accuracies of fibrous ring, nerve roots and bone were 100%, and the overall accuracy for all tissues was 73.33%. The results indicated that the combined parameter method provided more accurate classification output. It demonstrated that the proposed endoscopic ultrasonography system had the potential of identifying different tissues under surface during the endoscopic spine surgery.Clinical Relevance-This study establishes that the forward-oriented ultrasound endoscopic system was feasible to identify different types of tissues under surface during the endoscopic spine surgery.

Ultrasound-guided disc pain induction test for diagnosis of discogenic lumbar pain: a cross-sectional study.

BACKGROUND: Several methods can be used to diagnose discogenic pain, but only discoblock can diagnose discogenic pain definitively. This study aimed to examine the usefulness of an ultrasound-guided disc pain induction test for a simple and accurate diagnosis of the culprit lesion. METHODS: We included 41 patients with lumbar pain in whom pain was induced by an ultrasound-guided disc pain induction test. All patients had confirmed pain at L1/2 to L5/S1 based on an ultrasound-guided disc pain induction test and underwent X-ray photography and magnetic resonance imaging. Seventeen patients who required injection due to severe pain underwent discoblock procedures for discs with the most intense pain, and visual analogue scale (VAS) scores were obtained before and after the procedure for these patients. We analysed the association between painful discs and radiological findings. RESULTS: Pain induction was noted in a total of 65 discs, and the pain was induced in 23 patients in only one disc. All patients had disc degeneration of Pfirrmann classification grade 1 or higher, with more significant disc degeneration in painful discs than in painless discs. There was no significant relationship between the presence or absence of pain and Modic type. The average VAS measurements improved significantly from 9.5 (pre-procedure) to 2.5 (post-procedure). These results suggest that the most painful discs were the causes of discogenic lumbar pain. CONCLUSIONS: Our ultrasound-guided disc pain induction test may help diagnose disc degeneration and identify culprit lesions, even when multiple discs exhibit findings of degeneration.