Quantitative Pfirrmann Disc Degeneration Grading System to Overcome the Limitation of Pfirrmann Disc Degeneration Grade

Artificial intelligence: a new cutting-edge tool in spine surgery

The purpose of this narrative review was to comprehensively elaborate the various components of artificial intelligence (AI), their applications in spine surgery, practical concerns, and future directions. Over the years, spine surgery has been continuously transformed in various aspects, including diagnostic strategies, surgical approaches, procedures, and instrumentation, to provide better-quality patient care. Surgeons have also augmented their surgical expertise with rapidly growing technological advancements. AI is an advancing field that has the potential to revolutionize many aspects of spine surgery. We performed a comprehensive narrative review of the various aspects of AI and machine learning in spine surgery. To elaborate on the current role of AI in spine surgery, a review of the literature was performed using PubMed and Google Scholar databases for articles published in English in the last 20 years. The initial search using the keywords "artificial intelligence" AND "spine," "machine learning" AND "spine," and "deep learning" AND "spine" extracted a total of 78, 60, and 37 articles and 11,500, 4,610, and 2,270 articles on PubMed and Google Scholar. After the initial screening and exclusion of unrelated articles, duplicates, and non-English articles, 405 articles were identified. After the second stage of screening, 93 articles were included in the review. Studies have shown that AI can be used to analyze patient data and provide personalized treatment recommendations in spine care. It also provides valuable insights for planning surgeries and assisting with precise surgical maneuvers and decisionmaking during the procedures. As more data become available and with further advancements, AI is likely to improve patient outcomes.

A novel quantitative method to evaluate lumbar disc degeneration: MRI histogram analysis

PURPOSE

This study aimed to use MRI histogram analysis to routine MRI sequences to evaluate lumbar disc degeneration (LDD), illustrate the correlation between this novel method and the traditional Pfirrmann classification method, and more importantly, perform comprehensive agreement analysis of MRI histogram analysis in various situations to evaluate its objectivity and stability.

METHODS

Lumbar MRI images from 133 subjects were included in this study. LDD was classified into grades by Pfirrmann classification and was measured as peak separation value by MRI histogram analysis. Correlation analysis between the two methods was performed and cutoff values were determined. In addition, the agreement analysis of peak separation value was performed by intraclass correlation coefficient (ICC) in four scenarios, including inter-resolution, inter-observer, inter-regions of interest (ROI) and inter-slice.

RESULTS

Peak separation values were strongly correlated with Pfirrmann grades (r = - 0.847). The inter-resolution agreements of peak separation value between original image resolution of 2304 × 2304 and compressed image resolutions (1152 × 1152, 576 × 576, 288 × 288) were good to excellent (ICCs were 0.916, 0.876 and 0.822), except 144 × 144 was moderate (ICC = 533). The agreements of inter-observer (ICC = 0.982) and inter-ROI (ICC = 0.915) were excellent. Compared with the mid-sagittal slice, the inter-slice agreements were good for the first adjacent slices (ICCs were 0.826 and 0.844), and moderate to good for the second adjacent slices (ICC = 0.733 and 0.753).

CONCLUSION

MRI histogram analysis, used in routine MRI sequences, demonstrated a strong correlation with Pfirrmann classification and good agreements in various scenarios, expanding the range of application and providing an effective, objective and quantitative tool to evaluate LDD.

Increasing Cervical Kyphosis Correlates With Cervical Degenerative Disk Disease in Patients With Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective review.

OBJECTIVE

Our goal was to investigate the incidence of cervical degenerative disk disease (DDD) in patients with adolescent idiopathic scoliosis (AIS), before surgical intervention.

SUMMARY OF BACKGROUND DATA

AIS is often associated with thoracic hypokyphosis and compensatory cervical kyphosis. In adults, cervical kyphosis is associated with DDD. Although cervical kyphosis has been reported in up to 60% AIS patients, the association with cervical DDD has not been reported.

MATERIALS AND METHODS

A retrospective review was conducted from January 2014 to December 2019 of all consecutive AIS patients. Inclusion criteria were AIS patients over 10 years of age with cervical magnetic resonance imaging and anterior-posterior and lateral spine radiographs within 1 year of each other. Magnetic resonance imaging were reviewed for evidence of cervical DDD. Severity of cervical changes were graded using the Pfirrmann classification and by a quantitative measure of disk degeneration, the magnetic resonance signal intensity ratio.

RESULTS

Eighty consecutive patients were included (mean age: 14.1 years, SD=2.5 years). Increasing cervical kyphosis was significantly correlated to decreasing thoracic kyphosis ( r =0.49, P <0.01) and increasing major curve magnitude ( r =0.22, P =0.04). Forty-five patients (56%) had the presence of DDD (grades 2-4) with a mean cervical kyphosis of 11.1° (SD=9.5°, P <0.01). More cervical kyphosis was associated with more severe cervical DDD as graded by Pfirrmann classification level ( P <0.01). Increasing cervical kyphosis was also positively associated with increasing magnetic resonance signal intensity ratio ( P <0.01). Nine patients had ventral cord effacement secondary to DDD with a mean cervical kyphosis of 22.8° (SD=8.6°) compared with 2.6° (SD=11.2°) in those who did not ( P <0.01).

CONCLUSIONS

Cervical kyphosis was significantly associated with increasing severity of cervical DDD in patients with AIS. Patients with evidence of ventral cord effacement had the largest degree of cervical kyphosis with a mean of 22.8±8.6°. This is the first study to evaluate the association between cervical kyphosis in AIS with cervical DDD.

Tracing the disc: The novel qualitative morphometric MRI based disc degeneration classification system

Background

This study aimed to develop a classification system for lumbar disc degeneration using routine magnetic resonance images (MRIs) that is easily applicable and unaffected by existing classifications' limitations, and to compare its reliability, reproducibility, and discriminative power to the widely used Pfirrmann classification.

Methods

Five features were graded. This new classification system has eight grades, with at least one of these five features altering each grade. The T2-weighted sagittal images were acquired using a rapid spin-echo sequence with a repetition time of 2680 to 4900 milliseconds, an echo time of 100 to 109 milliseconds, and an echo train length of 17. Slice thick was 4 mm and the display field of view was 32 × 32 cm. The new classification system used five features: signal intensity, disc height, disc boundary regularity, and nucleus annulus separation. Increased signal intensity, decreased height, decreased regularity, and decreased nucleus-annulus separation indicated degeneration. Four raters classified 400 discs from 80 patients using the Pfirrmann and Novel systems. Statistical analyses were conducted to investigate reliability and correlation.

Results

The overall ICC and kappa values were found to be higher in the novel classification. (0.988 indicating excellent agreement for ICC and 0.76/0.94 indicating good-very good agreement for kappa). The Kendall tau c value, which shows the correlation between the two classifications and indicates the validity of the new classification, was 0.872, which is very strong. Through the use of cross-tabulations, the discriminatory power of the two newly added classification criteria was determined.

Conclusions

This study demonstrates the intra-rater and inter-rater reliability of an easy-to-use, discriminative novel morphometric MRI based classification system for lumbar disc degeneration. The differentiation of grades based on five distinct criteria may generate novel hypotheses regarding treatment selection and response monitoring, as well as new insights into the study of disc degeneration.

Does intervertebral disc degeneration in adolescent idiopathic scoliosis correlate with patient-reported pain scores? A review of 968 cases

PURPOSE

Report the rate and severity of degenerative disc disease (DDD) in non-surgical adolescent idiopathic scoliosis (AIS) patients and correlate these findings with patient-reported symptomatology scores. Additionally, to quantify the rate of concurrent pathological radiological findings in this group.

METHODS

This was a retrospective chart review study at a single tertiary centre. AIS patients aged 10-16 who had received a whole spine MRI between September 2007 and January 2019 and who had not received surgical intervention to their spine were included. MRI scan reports were screened to extract those who had evidence of DDD. These were then reviewed by a blinded second reviewer who graded every disc using the Pfirrmann grading system. SRS-22 scores were extracted for patients when available.

RESULTS

In total, 968 participants were included in the study. Of these, 93 (9.6%) had evidence of DDD, which was Pfirrmann grade ≥ 3 in 28 (2.9%). The most commonly affected level was L5/S1 (59.1% of DDD cases). A total of 55 patients (5.7%) had evidence of syringomyelia, 41 (3.4%) had evidence of spondylolisthesis (all L5/S1), 14 (1.4%) had bilateral L5 pars defects, and 5 (0.5%) had facet joint degeneration. Spondylolisthesis and bilateral pars defects were more common in patients with DDD identified on MRI scan (p < 0.001 and p = 0.04, respectively). Function (p = 0.048) and pain (p = 0.046) scores were worse in patients with DDD.

CONCLUSION

We present a baseline for the rate and severity of DDD in the non-operative AIS cohort. This should assist in decision-making and counselling of patients prior to surgery.

LEVEL OF EVIDENCE

III.

An Automatized Deep Segmentation and Classification Model for Lumbar Disk Degeneration and Clarification of Its Impact on Clinical Decisions

STUDY DESIGN

Cross-sectional database study.

OBJECTIVE

The purpose of this study was to develop a successful, reproducible, and reliable convolutional neural network (CNN) model capable of segmentation and classification for grading intervertebral disc degeneration (IVDD), as well as quantify the network's impact on doctors' clinical decision-making.

METHODS

5685 discs from 1137 patients were graded separately by four experienced doctors according to the Pfirrmann classification. A ground truth (GT) was established for each disc in accordance with the decision of the majority of doctors. The U-net model is used for segmentation. 1815 discs from 363 patients were used to train and test the U-net. The Inception V3 model is employed for classification. All discs were separated into two distinct sets: 90% in a training set and 10% in a test set. The performance metrics of these models were measured. Reliability tests were performed. The impact of CNN assistance on doctors was assessed.

RESULTS

Segmentation accuracy was .9597 with a .8717 Jaccard Index and a .9314 Sorensen Dice coefficient. Classification accuracy is .9346, and the F1 score is .9355. The intraclass correlation coefficient (ICC) and kappa values between CNN and GT were .95-.97. With CNN's assistance, the success rates of doctors increased by 7.9% to 22%.

CONCLUSIONS

The fully automated network outperformed doctors markedly in terms of accuracy and reliability. The results of CNN were comparable to those of other recent studies in the literature. It was determined that CNN's assistance had a substantial positive effect on the doctor's decision.

The Invasive Management of Pain: Diagnosis and New Treatment Options

Both the diagnosis and treatment of pain are evolving, especially in interventional approaches. Diagnosis of low back pain combines old and new methodologies, in particular, it involves an expanded role for ultrasound. While low back pain is a common complaint, there are many etiologies to the condition which must be explored before a final diagnosis can be made and treatment planned. Tumors and infections are rarely involved in low back pain but should be ruled out in the initial phase itself since failing to address them early can have devastating consequences. Some invasive treatments seem promising in the management of low back pain. Treating musculoskeletal pain with regenerative medicine, such as platelet-rich plasma, holds great promise. Autologous blood products are safe and may help stimulate the body's own responses for regeneration. The so-called "orthobiologics" play a role in sports medicine and the treatment of musculoskeletal pain. Neuromodulation, especially spinal cord stimulation, is undergoing a renaissance with new waveforms, devices, and a greater albeit incomplete understanding of its mechanisms of action. Spinal cord stimulation is not a first-line therapy and not all patients or all back problems respond to this treatment. Nevertheless, the therapy can be safe, effective, and cost-effective with appropriate patient selection. Radiofrequency ablation of nerves in the form of neurotomy can be effective in reducing the pain of osteoarthritis. These procedures, including the newer cooled radiofrequency neurotomy, can restore function, reduce pain, and may potentially have an opioid-sparing effect. Technical expertise in nerve and anatomy is needed for the use of this technique. This review article aims to provide updated information on some invasive intervention techniques in pain management.

The current state of radiodiagnostics of degenerative changes in the lumbar spine (literature review)

Examination of the spine using radiological methods remains the most frequently conducted study in the outpatient practice of almost any radiologist. In most cases, changes in the spine are degenerative and dystrophic in nature. These changes in the spine are the leading cause of loss of activity among adults and the elderly, and cover a wide range of age-related structural changes. It is of great importance to understand the possibilities and limitations of radiological methods of diagnostics. The description of morphological changes observed in degenerative and dystrophic changes requires the use of unified terminology and classifications among clinicians and radiologists.The aim. To present modern concepts in the assessment of degenerative changes of the spine using radiological methods. A description of the standardized international nomenclature of intervertebral disc pathology and current classifications of spinal canal stenosis are presented.Material and methods. For literature search, we used electronic databases MEDLINE (PubMed), eLibrary, EMBASE and Cochrane Library with a selection of sources published from 2000 to 2021. We analyzed the works devoted to the diagnosis of degenerative changes in lumbar spine and to degenerative stenosis.Conclusion. The key to productive communication between physicians is the uniformity or standardization of terminology and definitions used. It is important that the protocol of description, its terms, semantic expressions be uniform and understandable to specialists who are involved in the diagnosis and treatment of the spine. Magnetic resonance imaging is a valuable method in the diagnosis of degenerative changes of the spinal column, but it has its limitations.

The relationship between the degeneration and asymmetry of the lumbar multifidus and erector spinae muscles in patients with lumbar disc herniation with and without root compression

BACKGROUND

The determination of muscle pathologies in lumbar disc herniation (LDH) and other conditions with low back pain is important for understanding low back problems and determining appropriate treatment methods. In patients with lumbar disc herniation with radiculopathy, elucidating the effect of root compression on the severity of muscle degeneration may predict the importance of alleviating root compression. For this purpose, magnetic resonance imaging (MRI) was used to compare the degeneration and asymmetries of the lumbar musculus multifidus (MF) and lumbar musculus erector spinae (ES) muscles in patients with lumbar discopathy without root compression (radiculopathy) and in patients with lumbar discopathy with root compression (radiculopathy).

METHODS

The patients were examined in two groups: 56 patients with lumbar discopathy and no radiculopathy (Non-rad group) and 51 patients with lumbar discopathy and radiculopathy (Rad group). On axial MRI sections passing through the centre of the disc at the L3-S1 level, the asymmetry, cross-sectional area (CSA), fat infiltration, and total CSA (TCSA = MF + ES) of the MF and ES muscles were measured and compared.

RESULTS

No difference was seen between the groups with respect to the CSA values of the right and left MF and left ES, but a significant difference was found in the right ES CSA (p = 0.021). The CSA and TCSA of the MF and ES showed no asymmetry according to group. Severe fat infiltration of > 50% in the right and left MF and left ES was found in the Rad group at a higher rate than in the Non-rad group. Fat infiltration was significantly positively correlated with age, body mass index, and the duration of pain (p < 0.001, p < 0.001, p = 0.004, respectively).

CONCLUSIONS

The study results showed a correlation between LDH and paraspinal muscle degeneration, while no correlation was found with asymmetry. Severe (> 50%) fat infiltration is associated with root compression, and the severity of fat filtration increases in the presence of root compression. The development of more severe degeneration due to denervation associated with root compression plays a role in the emergence of this situation. Therefore, in patients with lumbar disc herniation with radiculopathy, it can be foreseen that to stop and correct severe fat infiltration and muscle degeneration, first, nerve root compression should be corrected with appropriate medical treatment methods, and in patients in whom there is no response, the pressure should be alleviated with appropriate surgical methods.

Immuno-Modulatory Effects of Intervertebral Disc Cells

Low back pain is a highly prevalent, chronic, and costly medical condition predominantly triggered by intervertebral disc degeneration (IDD). IDD is often caused by structural and biochemical changes in intervertebral discs (IVD) that prompt a pathologic shift from an anabolic to catabolic state, affecting extracellular matrix (ECM) production, enzyme generation, cytokine and chemokine production, neurotrophic and angiogenic factor production. The IVD is an immune-privileged organ. However, during degeneration immune cells and inflammatory factors can infiltrate through defects in the cartilage endplate and annulus fibrosus fissures, further accelerating the catabolic environment. Remarkably, though, catabolic ECM disruption also occurs in the absence of immune cell infiltration, largely due to native disc cell production of catabolic enzymes and cytokines. An unbalanced metabolism could be induced by many different factors, including a harsh microenvironment, biomechanical cues, genetics, and infection. The complex, multifactorial nature of IDD brings the challenge of identifying key factors which initiate the degenerative cascade, eventually leading to back pain. These factors are often investigated through methods including animal models, 3D cell culture, bioreactors, and computational models. However, the crosstalk between the IVD, immune system, and shifted metabolism is frequently misconstrued, often with the assumption that the presence of cytokines and chemokines is synonymous to inflammation or an immune response, which is not true for the intact disc. Therefore, this review will tackle immunomodulatory and IVD cell roles in IDD, clarifying the differences between cellular involvements and implications for therapeutic development and assessing models used to explore inflammatory or catabolic IVD environments.

TRIM21 drives intervertebral disc degeneration induced by oxidative stress via mediating HIF-1α degradation

The onset and progression of intervertebral disc degeneration (IVDD) is strictly associated with oxidative stress. TRIM21 (Tripartite motif-containing protein 21), a ubiquitin E3 ligase, has been shown to play an essential role in liver redox homeostasis; however, whether TRIM21 is involved in IVDD, especially in oxidative stress-induced IVDD, is unknown. Here, we reported that TRIM21 was upregulated in nucleus pulposus (NPs) with increasing severity of IVDD, and that oxidative stress was a stimulator of TRIM21 expression. Furthermore, we found that TRIM21 deficiency significantly protected NP cells from degeneration induced by oxidative stress as well as ameliorated disc degeneration in aged mice. Mechanistically, TRIM21 facilitated NP cells degeneration induced by oxidative stress via HIF-1α. TRIM21 could physically interact with HIF-1α and facilitated its degradation via its ubiquitylating activity. Taken together, these findings revealed that TRIM21 drived IVDD induced by oxidative stress by increasing HIF-1α degradation. These findings implicates the potential of TRIM21 as a therapeutic target in IVDD, especially in oxidative stress-induced IVDD.

Risk Factors of Secondary Lumbar Discectomy of a Herniated Lumbar Disc after Lumbar Discectomy

Objective

To study risk factors of secondary lumbar discectomy (LD) for recurrent herniated lumbar disc (HLD) and identify methods to lower the rate of recurrence.

Methods

Data from 160 patients who underwent primary LD were collected retrospectively. Demographic features, radiologic findings including Pfirrmann disc degeneration, and surgical information were analyzed to compare risks between revision and non-revision patients.

Results

The revision rate was 15% (24 patients), and the mean follow-up was 28.3 months. HLD recurrence was not related to any demographic characteristics. Primary and secondary LD were most common at the L4–5 level, but the level of operation was not significantly associated with revision. Primary LD most commonly had a Pfirrmann disc degeneration grade of 3, followed by 4. For recurrent HLD, Pfirrmann grade 4 was most common and was statistically significant (p<0.05). A body mass index (BMI) over 30 was considered obese and was significantly related with HLD revision (p<0.05).

Conclusion

Patients with high BMI or severe disc degeneration should be informed of HLD revision.

Dynamic functional nucleus is a potential biomarker for structural degeneration in cervical spine discs

If intervertebral disc degeneration can be identified early, preventative treatments may be initiated before symptoms become disabling and costly. Changes in disc mechanics, such as the decrease in the compressive modulus of the nucleus, are some of the earliest signs of degeneration. Therefore, in vivo changes in the disc response to compressive load may serve as a biomarker for pending or early disc degeneration. The aim of this study was to assess the potential for using in vivo dynamic disc deformation to identify pathologic structural degeneration of the intervertebral disc. A validated model-based tracking technique determined vertebral motion from biplane radiographs collected during dynamic flexion/extension and axial rotation of the cervical spine. A computational model of the subaxial intervertebral discs was developed to identify the dynamic functional nucleus of each disc, that is, the disc region that underwent little to no additional compression during dynamic movements. The size and location of the dynamic functional nucleus was determined for 10 C5/C6 spondylosis patients, 10 C5/C6/C7 spondylosis patients, and 10 asymptomatic controls. The dynamic functional nucleus size was sensitive (significantly smaller than controls in 5 of 6 measurements at the diseased disc) and specific (no difference from controls in 9 of 10 measurements at non-diseased discs) to pathologic disc degeneration. These results provide evidence to suggest that structural disc degeneration, manifested by changes in the disc response to functional loading, may be identified in vivo from dynamic imaging collected during functional movements. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-7, 2019.

Materials for the Spine: Anatomy, Problems, and Solutions

Disc degeneration affects 12% to 35% of a given population, based on genetics, age, gender, and other environmental factors, and usually occurs in the lumbar spine due to heavier loads and more strenuous motions. Degeneration of the extracellular matrix (ECM) within reduces mechanical integrity, shock absorption, and swelling capabilities of the intervertebral disc. When severe enough, the disc can bulge and eventually herniate, leading to pressure build up on the spinal cord. This can cause immense lower back pain in individuals, leading to total medical costs exceeding $100 billion. Current treatment options include both invasive and noninvasive methods, with spinal fusion surgery and total disc replacement (TDR) being the most common invasive procedures. Although these treatments cause pain relief for the majority of patients, multiple challenges arise for each. Therefore, newer tissue engineering methods are being researched to solve the ever-growing problem. This review spans the anatomy of the spine, with an emphasis on the functions and biological aspects of the intervertebral discs, as well as the problems, associated solutions, and future research in the field.

Whole Spine Disc Degeneration Survey according to the Ages and Sex Using Pfirrmann Disc Degeneration Grades

Objective

Pfirrmann disc grade is a useful scoring tool for evaluating disc degeneration, but normal values according to aging process has not been elucidated. This study was conducted to identify the prevalence and pattern of whole spine disc degeneration according to ages and gender differences.

Methods

Total 653 patients (336 male and 317 female patients, 48.1±58.7 years old) who took whole spine magnetic resonance images were enrolled in this study. There were 19 cases in their 2nd decades and 74 cases in 3rd decades, 141 cases in 4th decades, 129 cases in 5th decades, 139 cases in 6th decades, and 93 cases in 7th decades, 58 cases in over 8th decades. Pfirrmann disc grades were measured according to sex and ages by 2 neurosurgeons that were blind to this study.

Results

All spinal disc degeneration grades were correlated with ageing. The Pfirrmann disc grades of degeneration in all spine levels showed the statistically significant difference according to the ages (p<0.001). The common Pfirrmann disc grades according to the ages were grade 3 among 2nd to 5th decades, and grade 4 was more common than 6th decades. The lower cervical level (C2–3 to C4–5) and lumbar level (L1–2 to L5–S1) were happened relatively early severe disc degeneration compared to other levels. The intersexual differences were increased after 6th decades.

Conclusion

Disc degeneration is natural course after one’s 2nd decades. And its incidence and grade were increased with age, and more affected by sexual difference after 6th decades.

Apparent diffusion coefficient maps in the assessment of surgical patients with lumbar spine degeneration

Purpose

To assess the utility of apparent diffusion coefficient (ADC) maps for the assessment of patients with advanced degenerative lumbar spine disease and describe characteristic features of ADC maps in various degenerative lumbar spinal conditions.

Methods

T1-weighted, T2-weighted and diffusion weighted (DWI) MR images of 100 consecutive patients admitted to the spinal surgery service were assessed. ADC maps were generated from DWI images using Osyrix software. The ADC values and characteristic ADC maps were assessed in the regions of interest over the different pathological entities of the lumbar spine.

Results

The study included 452 lumbar vertebral segments available for analysis of ADCs. Characteristic ADC map features were identified for protrusion, extrusion and sequester types of lumbar disk herniations, spondylolisthesis, reactive Modic endplate changes, Pfirrmann grades of IVD degeneration, and compromised spinal nerves. Compromised nerve roots had significantly higher mean ADC values than adjacent (p < 0.001), contralateral (p < 0.001) or adjacent contralateral (p < 0.001) nerve roots. Compared to the normal bone marrow, Modic I changes showed higher ADC values (p = 0.01) and Modic 2 changes showed lower ADC values (p = 0.02) respectively. ADC values correlated with the Pfirrmann grading, however differed from herniated and non-herniated disks of the matched Pfirrmann 3 and 4 grades.

Conclusion

Quantitative and qualitative evaluation of ADC mapping may provide additional useful information regarding the fluid dynamics of the degenerated spine and may complement standard MRI imaging protocol for the comprehensive assessment of surgical patients with lumbar spine pathology. ADC maps were advantageous in differentiating reactive bone marrow changes, and more precise assessment of the disk degeneration state. ADC mapping of compressed nerve roots showed promise but requires further investigation on a larger cohort of patients.

Role of thymic stromal lymphopoietin in the pathogenesis of lumbar disc degeneration

BACKGROUND

This study aims to investigate the role of thymic stromal lymphopoietin (TSLP) in the pathogenesis of lumbar disc degeneration (LDD).

METHODS

Nucleus pulposus tissues were collected from 77 LDD patients (the case group), in addition, normal tissues were extracted from 21 patients suffering from lumbar fractures (the control group). Immunohistochemistry was applied in order to detect TSLP positive expression. In accordance with varying transfection, the cells were divided into TSLP-siRNA, TSLP-siRNA + TSLPR-siRNA, control, blank, anti-TSLPR, and IgG groups. Western blotting was used in order to detect TSLP expression in tissues, and TSLP and type II collagen (COL2AL) in cell culture media were detected using enzyme linked immunosorbent assay (ELISA). Cell viability was measured using a MTT assay. Aggrecan levels were detected using antonopulos, and cell apoptosis was determined using flow cytometry.

RESULTS

TSLP-positive expression was found to be significantly higher in the case group compared with the control group. LDD patients' Pfirrmann grades and preoperative visual analogue scale (VAS) scores were associated with TSLP-positive rate. Cells transfected with TSLP-siRNA and TSLPR-siRNA plasmids exhibited lower TSLP and thymic stromal lymphopoietin receptor (TSLPR) protein expression compared with the control and blank groups. Compared with the control and blank groups, there was significantly higher cell viability, lower cell apoptosis, and higher COL2AL and Aggrecan levels in the TSLP-siRNA, anti-TSLPR, and TSLP-siRNA+TSLPR-siRNA groups; there were significant differences between the TSLP-siRNA, anti-TSLPR, and TSLP-siRNA+TSLPR-siRNA groups and IgG group (all P < .05) CONCLUSION:: Our study provides evidence for the hypothesis that TSLP could reflect the histological severity of LDD, and TSLP-siRNA and, TSLPR-siRNA could inhibit apoptosis of nucleus pulposus cells. The evident information obtained from the investigation could lead the way for new therapeutic approaches regarding LDD treatment.

Correlation study between facet joint cartilage and intervertebral discs in early lumbar vertebral degeneration using T2, T2* and T1ρ mapping

Recent advancements in magnetic resonance imaging have allowed for the early detection of biochemical changes in intervertebral discs and articular cartilage. Here, we assessed the feasibility of axial T2, T2* and T1ρ mapping of the lumbar facet joints (LFJs) to determine correlations between cartilage and intervertebral discs (IVDs) in early lumbar vertebral degeneration. We recruited 22 volunteers and examined 202 LFJs and 101 IVDs with morphological (sagittal and axial FSE T2-weighted imaging) and axial biochemical (T2, T2* and T1ρ mapping) sequences using a 3.0T MRI scanner. IVDs were graded using the Pfirrmann system. Mapping values of LFJs were recorded according to the degeneration grades of IVDs at the same level. The feasibility of T2, T2* and T1ρ in IVDs and LFJs were analyzed by comparing these mapping values across subjects with different rates of degeneration using Kruskal-Wallis tests. A Pearson's correlation analysis was used to compare T2, T2* and T1ρ values of discs and LFJs. We found excellent reproducibility in the T2, T2* and T1ρ values for the nucleus pulposus (NP), anterior and posterior annulus fibrosus (PAF), and LFJ cartilage (intraclass correlation coefficients 0.806-0.955). T2, T2* and T1ρ mapping (all P<0.01) had good Pfirrmann grade performances in the NP with IVD degeneration. LFJ T2* values were significantly different between grades I and IV (PL = 0.032, PR = 0.026), as were T1ρ values between grades II and III (PL = 0.002, PR = 0.006) and grades III and IV (PL = 0.006, PR = 0.001). Correlations were moderately negative for T1ρ values between LFJ cartilage and NP (rL = -0.574, rR = -0.551), and between LFJ cartilage and PAF (rL = -0.551, rR = -0.499). T1ρ values of LFJ cartilage was weakly correlated with T2 (r = 0.007) and T2* (r = -0.158) values. Overall, we show that axial T1ρ effectively assesses early LFJ cartilage degeneration. Using T1ρ analysis, we propose a link between LFJ degeneration and IVD NP or PAF changes.

Correlation Between Expression of High Temperature Requirement Serine Protease A1 (HtrA1) in Nucleus Pulposus and T2 Value of Magnetic Resonance Imaging

BACKGROUND Degrading enzymes play an important role in the process of disc degeneration. The objective of this study was to investigate the correlation between the expression of high temperature requirement serine protease A1 (HtrA1) in the nucleus pulposus and the T2 value of the nucleus pulposus region in magnetic resonance imaging (MRI). MATERIAL AND METHODS Thirty-six patients who had undergone surgical excision of the nucleus pulposus were examined by MRI before surgery. Pfirrmann grading of the target intervertebral disc was performed according to the sagittal T2-weighted imaging, and the T2 value of the target nucleus pulposus was measured according to the median sagittal T2 mapping. The correlation between the Pfirrmann grade and the T2 value was analyzed. The expression of HtrA1 in the nucleus pulposus was analyzed by RT-PCR and Western blot. The correlation between the expression of HtrA1 and the T2 value was analyzed. RESULTS The T2 value of the nucleus pulposus region was 33.11-167.91 ms, with an average of 86.64±38.73 ms. According to Spearman correlation analysis, there was a rank correlation between T2 value and Pfirrmann grade (P<0.0001), and the correlation coefficient (rs)=-0.93617. There was a linear correlation between the mRNA level of HtrA1 and T2 value in nucleus pulposus tissues (a=3.88, b=-0.019, F=112.63, P<0.0001), normalized regression coefficient=-0.88. There was a linear correlation between the expression level of HtrA1 protein and the T2 value in the nucleus pulposus tissues (a=3.30, b=-0.016, F=93.15, P<0.0001) and normalized regression coefficient=-0.86. CONCLUSIONS The expression of HtrA1 was strongly related to the T2 value, suggesting that HtrA1 plays an important role in the pathological process of intervertebral disc degeneration.

Surgical anatomy, radiological features, and molecular biology of the lumbar intervertebral discs

The intervertebral disc (IVD) is a joint unique in structure and functions. Lying between adjacent vertebrae, it provides both the primary support and the elasticity required for the spine to move stably. Various aspects of the IVD have long been studied by researchers seeking a better understanding of its dynamics, aging, and subsequent disorders. In this article, we review the surgical anatomy, imaging modalities, and molecular biology of the lumbar IVD. Clin. Anat. 30:251-266, 2017. © 2017 Wiley Periodicals, Inc.

Rehydration of a degenerated disc on MRI synchronized with transition of Modic changes following stand-alone XLIF

Lumbar intervertebral disc degeneration (LDD) is known to be associated with low back pain (LBP) and leads to degenerative lumbar disease. LDD is considered to be irreversible, and no truly effective treatment that suppresses LDD or regenerates the degenerated disc has been established thus far. Here, we report the case of a 42-year-old woman with a 10-year history of persistent LBP. Magnetic resonance imaging (MRI) demonstrated degenerative changes (Pfirrmann classification: grade IV) in the L4-5 intervertebral disc with type I and III mixed Modic changes adjacent to the disc. Conservative treatments were not effective, so we opted for stand-alone extreme lateral interbody fusion (XLIF). One year after the operation, the LBP had almost disappeared. Follow-up MRI revealed transition of the Modic changes from type I to type III. In addition, rehydration of the degenerated disc behind the XLIF cage was evident (Pfirrmann classification changed from grade IV to grade II). To our knowledge, this is the first report of a change in LDD. Several factors are likely responsible for the regenerative response, including curettage of the hyaline cartilaginous endplates and auto-iliac cancellous bone grafting, which were considered to have affected nucleus pulposus cells in the residual disc.