Complications and local recurrence of chondrosarcoma and chordoma treated by total tumor resection in thoracic and lumbar spine.

BACKGROUND: En bloc resection of spinal tumors is challenging and associated with a high incidence of complications; however, it offers the potential to reduce the risk of recurrence when a wide margin is achieved. This research aims to investigate the safety and efficacy of en bloc resection in treating thoracic and lumbar chondrosarcoma/chordoma. METHODS: Data from patients diagnosed with chondrosarcoma and chordoma in the thoracic or lumbar region, who underwent total en bloc or piecemeal resection at our institution over a 7-year period, were collected and regularly followed up. The study analyzed overall perioperative complications and compared differences in complications and local tumor recurrence between the two surgical methods. RESULTS: Seventeen patients were included, comprising 12 with chondrosarcoma and 5 with chordoma. Among them, 5 cases underwent intralesional piecemeal resection, while the remaining 12 underwent planned en bloc resection. The average surgical time was 684 min (sd = 287), and the mean estimated blood loss was 2300 ml (sd = 1599). Thirty-five complications were recorded, with an average of 2.06 perioperative complications per patient. 82% of patients (14/17) experienced at least one perioperative complication, and major complications occurred in 64.7% (11/17). Five patients had local recurrence during the follow-up, with a mean recurrence time of 16.2 months (sd = 7.2) and a median recurrence time of 20 months (IQR = 12.5). Hospital stays, operation time, blood loss, and complication rates did not significantly differ between the two surgical methods. The local recurrence rate after en bloc resection was lower than piecemeal resection, although not statistically significant (P = 0.067). CONCLUSIONS: The complication rates between the two surgical procedures were similar. Considering safety and local tumor control, en bloc resection is recommended as the primary choice for patients with chondrosarcoma/chordoma in the thoracic and lumbar regions who are eligible for this treatment.

Modic Changes in the Lumbar Spine: Exploring Their Association with Abdominal Aortic Calcification as a Potential Indicator of Systemic Atherosclerosis.

BACKGROUND: This was a cross-sectional study on the correlation between abdominal aortic calcification (AAC) and Modic changes (MC). Little is known regarding the etiology of MC in the lumbar spine. Currently, insufficient vascularization of the endplate has been proposed to contribute to the appearance of MC. Our objective was to investigate whether AAC, a marker for a poor vascular status, is associated with MC in patients suffering from degenerative disc disease. METHODS: Radiologic images of patients (n = 130) suffering from degenerative lumbar disc disease were reviewed. Type and severity of MC were assessed using magnetic resonance images, and severity of AAC was evaluated using computed tomography images or fluoroscopy. Both items were dichotomized into minimal and relevant grades. The correlation between them was studied using Spearman's correlation test, with age as a covariate. RESULTS: Of the patients, 113 (87%) demonstrated MC (31% type I, 63% type II, and 6% type III) (55% relevant grade), and 68% had AAC (44% relevant grade). Spearman statistical analysis revealed that AAC was correlated with age (P < 0.001), whereas MC were not (P = 0.142). AAC severity was significantly correlated with MC, remaining so after age adjustment (P < 0.05). While MC type I lacked correlation with AAC, MC type II were significantly correlated with AAC (0.288, P = 0.015); however, this association lost significance after adjusting for age (P = 0.057). CONCLUSIONS: AAC and MC (mainly MC type II) are associated, indicating that reduced blood supply or even a poor systemic vascularization status due to atherosclerotic disease may play a role in the formation of MC. Future studies focusing on the etiology of MC should pay more attention to patients' vascular status and determinants of abdominal aorta calcification.

The Success of Deep Learning Modalities in Evaluating Modic Changes.

BACKGROUND: Modic changes are pathologies that are common in the population and cause low back pain. The aim of the study is to analyze the modic changes detected in magnetic resonance imaging (MRI) using deep learning modalities. METHODS: The sagittal T1, sagittal and axial T2-weighted lumbar MRI images of 307 patients, of which 125 were female and 182 were male, aged 19-86 years, who underwent MRI examination between 2016-2021 were analyzed. Modic changes (MC) were categorized and marked according to signal changes. Our study consists of 2 independent stages: classification and segmentation. The categorized data were first classified using convolutional neural network (CNN) architectures such as DenseNet-121, DenseNet-169, and VGG-19. In the next stage, masks were removed by segmentation using U-Net, which is the CNN architecture, with image processing programs on the marked images. RESULTS: During the classification stage, the success rates for modic type 1, type 2, and type 3 changes were 98%, 96%, 100% in DenseNet-121, 100%, 94%, 100% in DenseNet-169, and 98%, 92%, 97% in VGG-19, respectively. At the segmentation phase, the success rate was 71% with the U-Net architecture. CONCLUSIONS: Evaluation of MRI findings of MC in the etiology of lower back pain with deep learning architectures can significantly reduce the workload of the radiologist by providing ease of diagnosis.

Characteristics of lumbar spondylolysis: L5 versus non-L5.

BACKGROUND: Fifth lumbar vertebra (L5) spondylolysis has a lower bone union rate than non-L5 spondylolysis, but the reason for this is unknown. This study aimed to evaluate the differences in patient and lesion characteristics between L5 and non-L5 spondylolysis. METHODS: A total of 410 patients with lumbar spondylolysis aged 18 years or younger who were treated conservatively were enrolled. Patients and lesions were divided into L5 and non-L5 (L2-L4) spondylolysis. Factors, including sex, age, presence of spina bifida occulta, stage of the main side lesion, whether the lesion was unilateral or bilateral, presence and stage of the contralateral side lesion and treatment duration, were evaluated at the first visit and compared between the two groups. RESULTS: A total of 250 patients with 349 lesions were included. The bone union rate of L5 lesions was lower than that of non-L5 lesions (75% vs. 86%, p = 0.015). Patients with L5 spondylolysis were more likely to be male (86% vs. 66%) and younger (14.0 vs. 14.6 years) than patients with non-L5 spondylolysis. Lesions of L5 spondylolysis were more likely to be in a progressive stage (28% vs. 15%), less likely to be in a pre-lysis stage (28% vs. 43%) and more likely to be in a contralateral terminal stage (14% vs. 5.3%, p = 0.013) compared with lesions of non-L5 spondylolysis. CONCLUSIONS: L5 spondylolysis was characterised by a lower bone union rate, more males, younger age, more progressive stage and more contralateral pseudarthrosis than non-L5 spondylolysis.

Inter-software and inter-threshold reliability of quantitative paraspinal muscle segmentation.

PURPOSE: Changes in the cross-sectional area (CSA) and functional cross-sectional area (FCSA) of the lumbar multifidus (MF) and erector spinae muscles (ES) are factors that can contribute to low back pain. For the assessment of muscle CSA and composition there are various software and threshold methods used for tissue segmentation in quantitative analysis. However, there is currently no gold standard for software as well as muscle segmentation. This study aims to analyze the measurement error between different image processing software and different threshold methods for muscle segmentation. METHODS: Magnetic resonance images (MRI) of 60 patients were evaluated. Muscle CSA and FCSA measurements were acquired from axial T2-weighted MRI of the MF and ES at L4/L5 and L5/S1. CSA, FCSA, and FCSA/CSA ratio were measured independently by two observers. The MRI images were measured using two different software programs (ImageJ and Amira) and with two threshold methods (Circle/Overlap method) for each software to evaluate FCSA and FCSA/CSA ratio. RESULTS: Inter-software comparisons revealed high inter-rater reliability. However, poor inter-rater reliability were obtained with different threshold methods. CSA, FCSA, and FCSA/CSA showed excellent inter-software agreement of 0.75-0.99 regardless of the threshold segmentation method. The inter-rater reliability between the two observers ranged between 0.75 and 0.99. Comparison of the two segmentation methods revealed agreement between 0.19 and 0.84. FCSA and FCSA/CSA measured via the Overlap method were significantly higher than those measured via the Circle method (P < 0.01). CONCLUSION: The present study showed a high degree of reliability with very good agreement between the two software programs. However, study results based on different threshold methods should not be directly compared.

Do Modic changes contribute to lumbar instability or other way around? A retrospective study based on their types, extents, and affected lumbar segments.

BACKGROUND: Which types of Modic changes (MCs) and whether or how specific factors associated to MCs work on lumbar instability have yet to be well understood. The purpose of this study was to investigate the influences of the types of MCs, the extent of MCs lesion involvement, and different lumbar levels involved by MCs on lumbar instability. METHODS: This retrospective study included 263 adult subjects with MCs who underwent lumbar X-ray examinations in the neutral, flexion, and extension positions. All patients who met our inclusion criteria were examined with 1.5 Tesla magnetic resonance units. Two experienced authors with more than three-year clinical experience independently evaluated and measured the subjects' radiographic images. The subgroup analysis was performed to detect the differences in subjects' baseline characteristics and lumbar segmental motions among three types of MCs, the extent of MCs lesion involvement and different lumbar levels involved by MCs. RESULTS: There was a statistical difference in body mass index (BMI) between different involvement extent of MCs (p < 0.01), indicating that the subjects with high BMI are more likely to develop severe MCs. The subjects with Modic type 1 change (MC1) had a significant increase in lumbar angular motion than those with Modic type 2 change (MC2) and Modic type 3 change (MC3) (p < 0.01) and compared with MC3, a significant increase in lumbar translation motion was detected in subjects with MC1 and MC2 (p < 0.01). While, angular motion decreased, translation motion increased significantly as the extent of MCs lesion involvement aggravated (p < 0.01). However, there were no statistical differences in lumbar angular and translation motions between different lumbar levels involved by MCs (p > 0.05). CONCLUSIONS: Higher BMI might be a risk factor for the development of severe MCs. MC1 and MC2 significantly contribute to lumbar instability. The extents of MCs lesion involvement are strongly associated with lumbar instability. However, different lumbar levels involved by MCs have little effect on lumbar stability.

PILLAR: ParaspInaL muscLe segmentAtion pRoject - a comprehensive online resource to guide manual segmentation of paraspinal muscles from magnetic resonance imaging.

BACKGROUND: There is an increasing interest in assessing paraspinal morphology and composition in relation to low back pain (LBP). However, variations in methods and segmentation protocols contribute to the inconsistent findings in the literature. We present an on-line resource, the ParaspInaL muscLe segmentAtion pRoject (PILLAR, https://projectpillar.github.io/ ), to provide a detailed description and visual guide of a segmentation protocol by using the publicly available ITK-SNAP software and discuss related challenges when performing paraspinal lumbar muscles segmentations from magnetic resonance imaging (MRI). METHODS: T2-weighted and corresponding fat-water IDEAL axial MRI from 3 males and 3 females (2 chronic LBP and 1 control for each sex) were used to demonstrate our segmentation protocol for each lumbar paraspinal muscle (erector spinae, lumbar multifidus, quadratus lumborum and psoas) and lumbar spinal level (L1-L5). RESULTS: Proper segmentation requires an understanding of the anatomy of paraspinal lumbar muscles and the variations in paraspinal muscle morphology and composition due to age, sex, and the presence of LBP or related spinal pathologies. Other challenges in segmentation includes the presence and variations of intramuscular and epimuscular fat, and side-to-side asymmetry. CONCLUSION: The growing interest to assess the lumbar musculature and its role in the development and recurrence of LBP prompted the need for comprehensive and easy-to-follow resources, such as the PILLAR project to reduce inconsistencies in segmentation protocols. Standardizing manual muscle measurements from MRI will facilitate comparisons between studies while the field is progressively moving towards the automatization of paraspinal muscle measurements for large cohort studies.

Reliability of panoramic ultrasound imaging and agreement with magnetic resonance imaging for the assessment of lumbar multifidus anatomical cross-sectional area.

The aim of this study was to investigate the reliability of panoramic ultrasound (US) imaging and agreement with magnetic resonance imaging (MRI) for assessing the average lumbar multifidus anatomical cross-sectional area between the lumbar vertebral bodies L3-L5 (i.e., LMF ACSAL3-L5). US and MRI scans of 20 male youth competitive alpine skiers were collected. To test the intra- and interrater reliability of US, transversal panoramic scans were analyzed on two different days by the same rater and the analysis of the first day was compared with the analysis of a second rater. To examine the agreement between US and MRI, Bland-Altman analysis was performed. Intrarater reliability was excellent, and interrater reliability was weak to good for both sides. The bias between MRI and US was - 0.19 ± 0.90 cm2 (2.68 ± 12.30%) for the left side and - 0.04 ± 0.98 cm2 (- 1.11 ± 12.93%) for the right side (i.e., for both sides US slightly overestimated LMF ACSAL3-L5 on average). The limits of agreement were - 1.95 to 1.57 cm2 (- 26.70 to 21.30%) for the left side and - 1.95 to 1.88 cm2 (- 26.46 to 24.24%) for the right side. Panoramic US imaging may be considered a method with excellent intrarater and weak to good interrater reliability for assessing LMF ACSAL3-L5. Comparison with MRI showed large individual differences in some cases, but an acceptable bias between the two imaging modalities.

Enhanced grading methods for lumbar paraspinal fat infiltration and its prognostic value in predicting lumbar disc herniation.

BACKGROUND: The simplified 3-grade system for measuring fat infiltration in the paraspinal muscles is widely utilized. In comparing our proposed 4-grade system to the existing 3-grade system, we evaluated its impact on results and particularly its ability to predict disc herniation, ultimately highlighting deficiencies in the latter. The objective of this investigation was to validate the efficacy of our newly proposed semi-quantitative simplified 4-grade system for assessing fat infiltration, as compared to the existing literature-based simplified 3-grade system, in terms of their predictive value for lumbar disc herniation. METHODS: Infiltration of the right and left lumbar multifidus and erector spinae muscles were assessed using a semi-quantitative 3- and 4-grade fat infiltration system on axial magnetic resonance imaging sections at the L3-S1 level in all subjects, with comparison of results between groups. The correlation between these grading systems and lumbar disc herniation was investigated. RESULTS: The simplified 3-degree system for measuring fat infiltration was not effective in predicting lumbar disc herniation (p > 0.05), while the 4-degree system proved to be useful in predicting it (p < 0.05). In both grading systems, females were found to have a higher risk of lumbar disc herniation than males (p < 0.05), and the risk increased with age and body mass index (BMI) (p < 0.001). CONCLUSIONS: It was observed that using the 4-grade fat infiltration system to determine the level of fat infiltration in the paraspinal muscles is more effective in predicting lumbar disc herniation compared to the 3-grade system. The 4-grade fat infiltration grading system proves to be an efficient semi-quantitative method that can replace the simplified 3-grade system.

Do MRI-derived muscle moment-arms in patients with chronic low back pain differ from healthy individuals? A comparative study.

OBJECTIVES: The present study aimed to estimate the trunk muscles moment-arms in low back pain (LBP) patients and compare this data to those of healthy individuals. This research further explored whether the difference of the moment-arms between these two is a contributing factor to LBP. METHODOLOGY: Fifty patients with CLBP (group A) and 25 healthy controls (group B) were enrolled. All participants were subjected to magnetic resonance imaging of lumbar spine. Muscle moment-arms were estimated on a T2W axial section parallel to the disc. RESULTS: There was statistically significant differences (p < 0.05) in the sagittal plane moment-arms at L1-L2 for right erector spinae (ES), bilateral psoas and rectus abdominis (RA), right quadratus lumborum (QL), and left obliques; bilateral ES, QL, RA, and right psoas at L2-L3; bilateral QL, RA, and obliques at L3-L4; bilateral RA and obliques at L4-L5; and bilateral psoas, RA, and obliques at L5-S1. There was no statistically significant difference (p < 0.05) in the coronal plane moment-arms except for left ES and QL at L1-L2; left QL and right RA at L3-L4; right RA and obliques at L4-L5; and bilateral ES and right RA at L5-S1. CONCLUSIONS: There was a significant difference in muscle moment-arms of the lumbar spine's prime stabilizer (psoas) and primary locomotors (rectus abdominis and obliques) between LBP patients and healthy individuals. This difference in the moment-arms leads to altered compressive forces at intervertebral discs and may be one of the risk factors for LBP.

Comparison of magnetic resonance imaging findings among sciatica patients classified as centralizers or non-centralizers.

OBJECTIVE: To compare if the degenerative findings from MRI differ between the sciatica patients classified as centralizers (CEN) and non-centralizers (Non-CEN) according to the McKenzie Method of mechanical diagnosis and therapy. STUDY DESIGN: A cross-sectional study. METHODS: Patients (N = 100) referred to a spine clinic of a single tertiary hospital for specialist consultation for sciatica. The McKenzie-based assessment was performed by the mechanical diagnosis and therapy-trained physiotherapists. Clinical data and prevalence of lumbar MRI findings were compared between the groups. RESULTS: There was no significant difference in leg pain intensity between the groups. The Non-CEN had significantly more intense back pain, mean 56 (SD 30) and were more disabled 44 (SD 15) compared to the CEN mean 41 (SD 25) and mean 31 (11), measured with a visual analogue scale (0-100), and the Oswestry Disability Index (0-100), respectively. The CEN had more severe degenerative findings on MRI than the Non-CEN: vertebral end-plate changes were 63% and 43%; mean Pfirrmann's disc degeneration lumbar summary score was 12.8, and 10.6; and severity score of total damage was 12.0 and 10.1, respectively. There were differences neither in disc contour changes nor nerve root stenosis on MRI. CONCLUSIONS: Sciatica patients classified as non-centralizers had significantly more severe back pain, and were significantly more disabled than centralizers, who instead had more severe degenerative findings on MRI. Thus, classification to non-centralizers by the McKenzie method seems not predict higher incidence of degenerative findings on MRI compared to centralizers.

Duration of Back Pain Symptoms and Its Relationship to Paralumbar Muscle Volume.

OBJECTIVE: Paralumbar muscle volume has been indicated as an important factor for patients reporting back pain. Our goal was to determine if there is a statistically significant relationship between the duration of patients' back pain symptoms (>12 weeks or ≤12 weeks) and paralumbar muscle volume. METHODS: In this retrospective cohort study, paralumbar muscles on axial T2-weighted lumbar magnetic resonance images were outlined using ImageJ to determine the paralumbar cross-sectional area (PL-CSA) and lumbar indentation value (LIV) at the center of disc spaces from L1 to L5. The Goutallier classification was determined by the primary author. Quantile regression was performed to compare the PL-CSA, PL-CSA normalized by body mass index, and LIV between the 2 cohorts. Cohort A consisted of patients reporting symptoms ≤12 weeks, and cohort B included patients with symptoms >12 weeks. Negative binomial regression was used to compare Goutallier class. RESULTS: A total of 551 patients operated on by a single surgeon with lumbar magnetic resonance imaging within the past 12 months and recorded duration of symptoms were included. Cohort A consisted of 229 patients (41.6%), and cohort B included 322 patients (58.4%). Statistical significance was not found at any lumbar level for PL-CSA, PL-CSA normalized by body mass index, Goutallier class, and LIV. CONCLUSIONS: Our results suggest that duration of symptoms may not be an accurate indicator for lumbar muscle volume. These novel findings are clinically valuable because lumbar muscle volume has been shown to be a marker for recovery. With this information, patients previously believed to be inoperable because of long-standing symptoms can be reevaluated.

Loss of lumbar disc height with age and its impact on pain and sensitivity associated behaviors in mice.

PURPOSE: Aging is a risk factor for several debilitating conditions including those related to chronic back pain and intervertebral disc degeneration, both of which have no cure. Mouse models are useful tools for studying disc degeneration and chronic back pain in a tightly controlled and clinically relevant aging environment. Moreover, mice offer the advantage of carrying out longitudinal studies to understand the etiology and progression of disc pathology induced by genetic or surgical strategies. Previously, age-related behavioral trends of discomfort and enhanced nociception in mice were reported; however, whether these measures are mediated by structural and pathological changes in the disc is unknown. METHODS: The goal of the present observational study was to identify behavioral correlates of age-related degenerative changes in the disc. Towards this, we collected radiographs from 150 mice (77 females) between three and 23 months of age and measured the disc height index for each level of lumbar disc. Behavioral measures were collected on several of these mice which included rearing and distance travelled in an open field test; time spent in rearing, reaching, immobile, and self-suspended in the tail suspension test; bilateral hind paw licking in response to cold allodynia using acetone; and unilateral hind paw licking in response to heat hyperalgesia using capsaicin. RESULTS: Results show that the lower lumbar discs lose height with age and these changes are independent of body composition measures including body weight, bone mineral density, fat mass, lean weight mass, percent fat mass, and percent lean mass. Disc height positively correlates with rearing and mobility in the open field test, immobility in the tail suspension test, and thermal hyperalgesia. Disc height negatively correlates with cold allodynia and rearing in the tail suspension test. Furthermore, mediation analysis shows that the lumbosacral disc significantly mediates the effect of age on rearing in the open field test, but not cold allodynia, suggesting this behavior is a useful measure of age-related axial discomfort due to disc degeneration. CONCLUSION: In summary, the findings from the current study show that disc height are associated with measures of axial discomfort and nociception in mice.

Treatment of L5-S1 spondyloptosis with stand-alone anterior lumbar interbody fusion in a patient with neurofibromatosis.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a multisystem disorder that causes multiple tumor formations throughout the nervous system. Common spinal dysplasias seen with NF1, such as dural ectasia (DE), often undergo modulation and predispose these patients to spondylolisthesis, making surgical treatment challenging. CASE DESCRIPTION: A patient with NF1 presented with a 12-year-history of back and left lower extremity radicular pain. Lumbar spine magnetic resonance imaging revealed developmental anomalies with severe DE and associated scalloping of the L4-S1 vertebral bodies and severe L5-S1 Meyerding grade 4 spondylolisthesis. During surgery, post-positioning x-rays demonstrated a grade 5 spondyloptosis. The patient underwent an L5-S1 stand-alone anterior lumbar interbody fusion (ALIF). The final construct was an ALIF cage with one screw into S1, without an anterior plate. By 3-months post-operative, there was complete resolution of preoperative symptoms and at 2 year follow-up the patient was asymptomatic with stable hardware and solid bony fusion. To the authors' knowledge, this is the first report of spondyloptosis treated with a stand-alone ALIF in a patient with NF1 and severe DE.

Spinal myelolipoma - an extremely rare pathology within the lumbar spine: a case report and literature review.

Myelolipoma is a benign tumor containing mature adipose cells and a combination of myeloid and erythroid elements. This tumor is typically found in the adrenal glands; however, it has been detected outside the adrenal glands in rare cases. We report an extremely rare case of myelolipoma in the lumbar spine causing significant neural compression due to the involvement of the posterior spinal elements. Given the significant neurological deficit, the patient was surgically managed as soon as possible. Extra-adrenal myelolipomas are rare lesions, and only one case has been reported in the spine so far. However, this diagnosis should be considered in cases with its characteristic imaging features.

A rare discal cyst with concurrent double-level isthmic lumbar spondylolisthesis: a case report and literature review.

We presented a 47-year old male diagnosed as a discal cyst with concurrent isthmic lumbar spondylolisthesis, which was not reported in the literature previously. A cystectomy with two-segmental transforaminal lumbar interbody fusion and instruments was performed. The association between concurrent discal cyst and isthmic spondylolisthesis may be illuminated by excessive strain and focal degeneration of the disc. Preoperative discography is probably unnecessary when surgical resection and histopathology are indicated for the patient.

Recurrent spinal meningeal melanocytoma at lumbar spine level: a case report.

INTRODUCTION: Spinal meningeal melanocytoma is an extremely rare tumour with an estimated annual incidence of 1 per 10 million people. It usually arises from the intradural extramedullary compartment at the cervical levels. Although these tumours are histologically benign, they may behave aggressively. Local recurrence could occur even after total tumour excision. CASE REPORT: We report a case of a 33-year-old Asian male who developed progressive weakness and numbness of the bilateral lower extremities as well as urinary retention five years after complete tumour resection of lumbar spinal meningeal melanocytoma. Magnetic resonance imaging of the lumbar spine revealed a mass with thecal sac compression which was hypointense on T2-weighted images and hyperintense on T1-weighted images. The patient underwent total tumour removal. Histologic examination was compatible with recurrent meningeal melanocytoma. After a 4-week inpatient rehabilitation programme, he was able to ambulate without assistance and to do clean intermittent catheterisation for micturition on a regular basis. DISCUSSION: This is the first reported case of intradural extramedullary meningeal melanocytoma located at the lumbar region. Clinicians should consider the possibility of these rare tumours at any level of the spine, and be aware of sphincter dysfunction in addition to motor and sensory deficits of extremities.

Update on the roles of macrophages in the degeneration and repair process of intervertebral discs.

Intervertebral disc (IVD) degeneration is the common cause of lumbar degenerative diseases, causing severe social and economic burden. The process of IVD degeneration involves a complex of pathologic changes on both extracellular matrix degradation and resident cell apoptosis. In recent years, there is increasing evidence that macrophages play vital roles during the damage and repair process of IVD degeneration. Nevertheless, the interactions between macrophages and IVD are not well understood, even if the IVD has long been regarded as the immune privileged site. Therefore, this review mainly focuses on the progress and obstacles of studies investigating the blood supply, immune response and especially macrophages during the IVD degeneration process.