Imaging Analysis of the High-Intensity Zone on Lumbar Spine Magnetic Resonance Images: Classification, Features and Correlation with Low Back Pain.

AIM: Early studies suggested that the high-intensity zone (HIZ) on lumbar MRI was a diagnostic sign of painful internal disc disruption (IDD). However, recent studies have questioned its diagnostic value. This study is conducted to explore imaging features of HIZ and to investigate the correlation between these characteristics and low back pain (LBP), further studying the predictive value of HIZ. METHODS: A retrospective study of 1188 cases was performed. MR images were read and analyzed by two experienced, blinded radiologists. RESULTS: A total of 575 (48.4%) individuals exhibited HIZ. The prevalence of posterior HIZ (32.3%) was significantly higher than that of anterior HIZ (23.6%; P < 0.01). Round type was the most common shape (61.0%) on sagittal view. Only 37 HIZs (4.6%) were identified on axial views. A total of 263 HIZ discs (32.5%) were found to have additional diagnostic signs of IDD, which is difficult to distinguish from the annulus fibrosus. In subjects with consecutive slides showing HIZ, the incidence of LBP was significantly higher than in single-slide HIZ individuals (58.0% vs 48.6%, P < 0.05). CONCLUSION: MRI-visualized HIZ is a highly valuable method of screening for lumbar IDD. It is demonstrated that consecutive-slide HIZ was a more reliable indicator for discogenic LBP than single-slide HIZ.

Anterior High-Intensity Zone in Lumbar Discs: Prevalence and Association with Low Back Pain.

OBJECTIVES: To explore the features of high-intensity zone (HIZ) in anterior annulus fibrosus and assess the association of anterior HIZ with low back pain (LBP). DESIGN, SETTING, AND SUBJECTS: A retrospective study of 5,940 discs in 1,188 individuals was conducted. METHODS: Subjects' information and LBP symptoms confirmed by an orthopedic surgeon were acquired from the medical record. Magnetic resonance (MR) image reading and analysis were performed by two experienced blinded radiologists. RESULTS: Two hundred eighty individuals exhibited 355 anterior HIZs in 355 discs. The prevalence was 23.57%; 88.45% were located in the inferior part of the annulus fibrosus. It frequently occurred in the middle and upper segments of lumbar spine, especially at L3/4 (45.63%). Of the 355 anterior HIZs, only 79 (22.25%) were consecutive-slides HIZ. Round type (63.38%) was the most common shape of anterior HIZs. The highest prevalence was found in individuals aged 60-69 years. LBP was confirmed in 141 anterior-HIZ individuals. The incidence of LBP in anterior-HIZ individuals was significantly higher than in non-HIZ subjects (50.36% vs 35.24%, χ2 = 18.314, P < 0.001). CONCLUSIONS: Anterior HIZ is a lower-prevalence, age-related sign on lumbar MR images. The spatial distribution of anterior HIZ can be distinguished from posterior HIZ. The number of consecutive anterior HIZ slides might suggest fewer Dallas grade 4 anterior annular disruptions in this sample. Anterior HIZ was correlated with LBP.

The research of transgenic human nucleus pulposus cell transplantation in the treatment of lumbar disc degeneration.

The present study determines whether the in vivo injection of TGFß1 and CTGF mediated by AAV2 to transfect nucleus pulposus cells in degenerative lumbar discs can reverse the biological effects of rhesus lumbar disc degeneration. A total of 42 lumbar discs obtained from six rhesus monkeys were classified into three groups: experimental group, control group, and blank group. Degenerative lumbar discs were respectively injected with double gene-transfected human nucleus pulposus cells using minimally invasive techniques. Immumohistochemical staining, RT-PCR, and western blot were performed to observe the biological effects of double gene-transfected human nucleus pulposus cells in degenerative lumbar discs on rhesus lumbar disc degeneration. At 4, 8, and 12 weeks after the transplantation of nucleus pulposus cells, the expression levels of TGF-ß1, CTGF, proteoglycan mRNA, and type-II collagen were detected by RT-PCR. The values of immumohistochemical staining and RT-PCR in the experimental group increased at 8 weeks, decreased with time at 12 weeks, and remained greater than the values in the control group, and the differences were statistically significant (P < .05). The western blot revealed that the values in the experimental group decreased with time, but remained greater than those in the PBS control group and blank control group, and the differences were statistically significant (P < .05). The double gene-transfection of human nucleus pulposus cells in degenerative lumbar discs mediated by rAAV2 can be continuously expressed in vivo after transplantation in lumbar discs of rhesus monkeys, and promotes the synthesis of proteoglycan and type II collagen, achieving the treatment purpose.

Factors associated with lumbar disc high-intensity zone (HIZ) on T2-weighted magnetic resonance image: a retrospective study of 3185 discs in 637 patients.

BACKGROUND: It is well known that internal disc disruption (IDD) is accelerated by factors such as aging and injury. High- intensity zone (HIZ) on lumbar MRI is usually considered a marker of painful IDD. However, many painful IDD show no HIZ. This suggests that the risk factors of HIZ may be different to these of IDD. The purpose was to clarify the correlation between the HIZ on lumbar MR and the factors, including gender, age, body weight, and low back pain (LBP). METHODS: Characteristics were obtained from the medical record. The MR images, biplanar post-discography radiographs, and post-discography CT images were reviewed and rated by two experienced radiologists in a blinded fashion. RESULTS: Annular HIZ correlated significantly with age (OR = 1.011), body weight (OR = 1.022), and LBP symptom (OR = 1.527). The lowest two HIZ prevalence rates were in the second and the third decades (11.54% and 7.84%). The highest prevalence was in the sixth decade (38.03%). The body weight was positively associated with the HIZ prevalence. There was a significant difference in HIZ prevalence between symptomatic and asymptomatic patients (36.16% vs. 26.96%, P < 0.05). All the HIZ discs exhibited grade 3 or grade 4 disruptions, but only 9 discs (9/16, 8 exhibited grade 4 annular tears) were detected with exact pain reproduction. CONCLUSIONS: It is demonstrated that the presence of HIZ on lumbar MR image was associated with aging, high body weight, and low back pain symptom. HIZ sign indicated a part of the natural history of disc degeneration but was not an actual source of low back pain.

Effects of AAV2-mediated co-transfection of CTGF and TIMP1 genes on degenerative lumbar intervertebral discs in rhesus monkeys in vivo.

OBJECTIVE: This study aims to investigate the effects of co-transfection of the genes for connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase-1 (TIMP1) mediated by adeno-associated virus 2 (AAV2) on degenerative lumbar intervertebral discs in a primate model. METHODS: Twelve 4-7 year-old rhesus monkeys weighing 4.5-7.0 kg were utilized. CTGF and TIMP1 genes carried by AAV2 were injected into the degenerative lumbar intervertebral discs. Cytokine expression and biological effects were determined using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and 35S-sulfate incorporation assays. A rhesus monkey model of intervertebral disc degeneration was successfully established. RESULTS: At post-transfection, CTGF mRNA expression was higher in the transfection group than in the control group (P < 0.05). Furthermore, TIMP1 mRNA expression in the transfection group was several times the levels observed in the control group (P < 0.05). Moreover, type-II collagen mRNA expression was higher in the transfection group than in the control group (P < 0.05). In addition, higher aggrecan mRNA expression and synthesis were observed in the transfection group, compared to that in the control group (P < 0.05). CONCLUSION: The stable expression of CTGF and TIMP1 genes in vivo promoted the synthesis of aggrecan and type II collagen in the nucleus pulposus in the rhesus monkey model of intervertebral disc degeneration, which has a potential for intervertebral disc regeneration.

Lentivirus-mediated TGF-ß3, CTGF and TIMP1 gene transduction as a gene therapy for intervertebral disc degeneration in an in vivo rabbit model.

The present study examined the effects of transforming growth factor (TGF)-ß3, connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase 1 (TIMP1) gene transduction, using a lentiviral vector, on rabbit intervertebral disc degeneration in vivo, with the intention of investigating their potential use in gene therapy. A model of lumbar intervertebral disc degeneration was created by needle puncture into the annulus fibrosus of 15 New Zealand white rabbits. Empty lentivirus or recombinant lentiviral plasmid lenti-TGFß3-P2A-CTGF-T2A-TIMP1 was injected into degenerative lumbar intervertebral discs (representing the control and experimental groups, respectively), whilst untreated degenerative lumbar intervertebral discs served as the puncture group. After 16 and 20 weeks, magnetic resonance imaging (MRI) was conducted and the changes in intensity on micrographs of degenerative intervertebral discs were measured. The mRNA levels of aggrecan and type II collagen in nucleus pulposus tissue were determined by reverse transcription-polymerase chain reaction, and protein expression levels of type II collagen and aggrecan were determined by western blot analysis. MRI results indicated that intervertebral disc degeneration was ameliorated in the experimental group when compared with the control and the puncture group. Furthermore, the expression levels of type II collagen and aggrecan in the puncture and control groups were significantly lower than in the experimental group (P<0.05). In conclusion, lenti-TGFß3-P2A-CTGF-T2A-TIMP1 co-transduction can promote synthesis of aggrecan and type II collagen in degenerative intervertebral discs, thereby delaying intervertebral disc degeneration. These results indicate the potential of gene therapy in treatment of intervertebral disc degeneration.

Effect of rAAV2-hTGFß1 Gene Transfer on Matrix Synthesis in an In Vivo Rabbit Disk Degeneration Model.

STUDY DESIGN: In vivo gene transfer for disk regeneration. OBJECTIVE: To evaluate the efficiency and effect of human transforming growth factor ß1 (hTGFß1) gene transfer mediated by adeno-associated virus (AAV) in a rabbit disk degeneration model induced by fibronectin fragment (Fn-f). SUMMARY OF BACKGROUND DATA: Gene therapy for disk degeneration has been reported to be effective. Nevertheless, few investigations have targeted the degenerative nucleus pulposus (NP) cells in vivo. Fn-f-induced degeneration has been previously verified to be a useful model for the study of disk degeneration at the molecular level. AAV vector is well suited for gene transfer in the disk for its lower immunogenicity and higher safety. MATERIALS AND METHODS: The early dedifferentiated NP cells were transfected with rAAV2-mediated enhanced green fluorescent protein (EGFP) gene in vitro. Fluorescence expression was observed 48 hours later. The rabbit disk degeneration model was established with a microinjection of Fn-f. Ninety-six degenerative disks of 24 rabbits were injected with rAAV2-hTGFß1 (group A), rAAV2-EGFP (group B), or PBS (group C). Immunohistochemical staining for hTGFß1 and fluorescence observation were performed at the 1- and 12-week time points, respectively. 35S-sulfate incorporation assay and Western blot analysis were used to measure the synthesis of proteoglycan and collagen type II at 4-, 8-, and 12-week time points. RESULTS: The dedifferentiated NP cells exhibited intensive fluorescence expression in vitro, with a transfection rate of 90%. In vivo, disks in group A showed enhanced positive hTGFß1 immunostaining at the 1-week time point. At the 4-, 8-, and 12-week time points, disks in group A exhibited significantly increased proteoglycan and collagen type II synthesis compared with the other 2 groups (P<0.01). Abundant green fluorescence was observed in the disks in group B at the 12-week time point. CONCLUSIONS: Early degenerative NP cells are susceptible to AAV-mediated gene transfer in vitro and in vivo. The rapid and prolonged target protein expressions and increased matrix synthesis indicated that AAV-mediated therapeutic gene transfer can be a promising form of treatment for disk regeneration in vivo.

Thoracic intervertebral disc calcification and herniation in adults: a report of two cases.

PURPOSE: Acute paraplegia due to thoracic intervertebral disc protrusion and calcification is rare. The purpose of this study was to report two cases with acute paraplegia due to a calcified thoracic disc prolapse, and discuss its clinical diagnosis and surgical treatment with literature reviews. METHODS: These two cases were verified by patient history, physical examination, laboratory examination, CT and MRI studies, and pathological findings. RESULTS: CT scan revealed disc calcification and protrusion at the T11-12 level in case 1 and at the T10-11 level in case 2, respectively. MRI images revealed severe spinal cord compression with a hyperintense central core and surrounding hypointense area in two cases, which were directly connected to the calcified intervertebral nucleus pulposus. Pathological examination revealed calcium deposition. Patients underwent discectomy followed by interbody fusion, and satisfactory therapeutic outcomes were obtained. CONCLUSIONS: We suggest that decompression surgery should be carried out as early as possible for patients with early spinal myelopathy or paraplegia caused by a calcified protruded disc.

One stage laminoplasty and posterior herniotomy for the treatment of myelopathy caused by cervical stenosis with cervical disc herniation.

The aim of the study was to introduce a method of one stage laminoplasty and posterior herniotomy for myelopathy caused by cervical stenosis with cervical disc herniation and to evaluate the clinical efficacy of this surgery. From 1999 to 2008, 18 patients with myelopathy caused by cervical stenosis with cervical disc herniation who underwent this procedure were included. The average age was 63 years (range 48-74 years), and the average follow-up period was 46 months (range 3-108 months). Neurologic status was evaluated using the JOA scoring system. Neurological symptoms improvement was seen in all patients after surgery. The average JOA score was 14.22±1.86 by final follow-up, which was higher than preoperative values (P<0.01), and the average improvement in neurological function was 76.63%. Neurologic examination showed that excellent results had been obtained by 10 patients, good results by 8 patients, with no fair or poor results. 2 patients developed cerebrospinal fluid leakage after surgery and recovered during the follow-up period. One patient with cervical disc herniation developed postoperative C5 palsy on the axle side on the third day after surgery. She completely recovered by 1 month after surgery. No other patients experienced postoperative neurologic complications. Complete anterior and posterior decompression of the spinal cord was achieved after surgery. We concluded that one stage laminoplasty and posterior herniotomy is an effective, reliable, and safe procedure for the treatment of myelopathy caused by cervical stenosis with cervical disc herniation.

Single-stage combined anterior retropharyngeal and posterior approach for the resection and reconstruction of C2 metastatic tumors: A case report.

This study reports the case of a 44-year-old male who had experienced severe neck pain for one month and was diagnosed with a metastatic tumor of the left C2 vertebral body and the left transverse process. The tumor was distributed to layers A-D and sectors 3-7 according to the Weinstein-Boriani-Biagini classification, and was in Category IV according to the Harrington classification system. A conventional posterior cervical approach was used to resect the left transverse process and part of the tumor in a piecemeal fashion, and spinal instrumentation was also performed. Gelfoam and absorbable hemostatic gauze were placed ventrally to the left vertebral artery and the left C3 nerve root over the tumor bed to prevent their accidental injury in the subsequent anterior approach. A high anterior retropharyngeal approach was then used to resect the tumorous C2 vertebral body by corpectomy and to perform anterior reconstruction. Six months after the surgery, the patient remained pain free. Therefore, C2 metastatic tumor resection and spinal reconstruction can be fulfilled by a single-stage combined high anterior retropharyngeal and posterior approach.

A radical procedure of circumferential spinal cord decompression through a modified posterior approach for thoracic myelopathy caused by severely impinging anterior ossification.

BACKGROUND CONTEXT: Thoracic myelopathy caused by an anterior, massive ossified plaque is often progressive and responds poorly to conservative treatment. Direct removal of the compressing ossification is the optimal procedure for a spinal cord that is severely impinged anteriorly. However, both anterior and posterior decompressive manipulations have caused catastrophic iatrogenic spinal cord injuries. A comprehensive treatment method for severe thoracic myelopathy that enables a sufficient and safe decompression of the spinal cord is needed. PURPOSE: The purpose of this study is to demonstrate the efficacy, safety, and results of a one-stage circumferential decompressive procedure using a modified posterior approach in patients with severe thoracic myelopathy resulting from anterior spinal compression. STUDY DESIGN: A modified procedure of circumferential spinal cord decompression for thoracic myelopathy is described. A retrospective study was conducted to investigate the clinical outcomes of 23 sequentially treated patients. PATIENT SAMPLE: Twenty-three patients were treated sequentially with a modified procedure for circumferential spinal cord decompression for thoracic myelopathy. OUTCOME MEASURES: Outcomes were assessed using the Japanese Orthopedic Association (JOA) score, modified Frankel classification, Hirabayashi recovery rate, and a general assessment of complications. METHODS: Twenty-three patients with thoracic myelopathy caused by a massive, anterior ossified structure were treated with an extensive posterior laminectomy, anterior removal of the ossification, and interbody fusion with kyphosis-reversing stabilization through a modified posterolateral approach. The neurologic outcomes are evaluated according to the JOA and the modified Frankel classification before surgery, 2 weeks after surgery, 1 year after surgery, and at the final follow-up visit. The surgical outcomes are also described using the Hirabayashi recovery rate. Radiographs, computed tomography (CT), and magnetic resonance imaging were performed before and after surgery. A postoperative CT scan was obtained to determine the efficacy of the decompression. Operative time, intraoperative blood loss, and complications were reviewed from the medical records. In addition, a 48-year-old man who presented with severe thoracic myelopathy resulting from anterior impingement with multiple osteophytes is described as an illustrative patient. RESULTS: The sites of ossification in this series were distributed widely, from T4-T12. The anterior ossified plaques of all patients were resected completely. Five patients who had intraoperative evidence of dural ossification required resection of the ossified dura matter. The average operating time was 276 minutes. Mean intraoperative blood loss was 1,350 mL. The postoperative follow-up ranged from 2.5 to 6 years, with an average of 4.6 years. The average preoperative JOA score was 4.3±1.5 points, and it improved to 6.1±1.9 points 2 weeks postoperatively, to 8.1±1.8 points 1 year postoperatively, and to 8.5±1.9 points at the most recent follow-up. The overall Hirabayashi recovery rate at the final examination averaged 63.6±22.4%. Eight patients were graded as excellent, 10 as good, 4 as fair, and 1 as unchanged. No patient was graded as deteriorated. The paralysis improved by at least 1 grade in 22 patients (95.7%). Transient deterioration of thoracic myelopathy occurred immediately after surgery in three patients (13%). Cerebrospinal fluid leakage occurred in six patients (26.1%). One patient sustained severe bilateral groin pain, three had unilateral intercostal neuralgia, and pleura tear occurred in one patient. CONCLUSION: One-stage posterior decompression, anterior extirpation of the ossification, and interbody fusion with instrumentation via a modified posterior approach is a safe and effective treatment for severe thoracic myelopathy resulting from prominent anterior impingement. This procedure is technically demanding, and the indications are limited to thoracic myelopathy caused by severe anterior impingement of various etiologies from T4-T12.

Treatment of rabbit intervertebral disc degeneration with co-transfection by adeno-associated virus-mediated SOX9 and osteogenic protein-1 double genes in vivo.

Degeneration of the lumbar intervertebral disc is a common cause of low back pain and leg pain that affects the physical and mental health of the patient and increases the social burden. This study was performed to observe the biological effects of adeno-associated virus (AAV)-mediated osteogenic protein-1 (OP1) and SOX9 double gene co-transfection in rabbit intervertebral disc degeneration in vivo. The animals were randomly grouped into models of disc degeneration. After injecting 20 µl of double-gene mixed solution, OP1, SOX9, enhanced green fluorescent protein (EGFP) and PBS buffer into the disc of each group, X-ray analysis, magnetic resonance imaging (MRI), reverse transcription PCR (RT-PCR) and western blotting were performed on the 3rd, 6th and 9th week of surgery. On the 3rd, 6th and 9th week of the transfection, X-ray and MRI showed that the intervertebral height and T2-weighted signal intensity were restored significantly in groups A, B and C, whereas significant differences in intervertebral space and T2-weighted signal intensity were observed between group A and groups B and C (P<0.05). RT-PCR and western blotting showed that the expression of type II collagen and proteoglycan mRNA was upregulated in groups A, B and C. The expression in group A was significantly higher than that in the other groups (P<0.05). Recombinant AAV-mediated SOX9 and OP1 double-gene transfection significantly ameliorated the height of the degenerative intervertebral disc and significantly promoted the high expression of degenerative disc proteoglycan and type II collagen. It can therefore be concluded that dual-gene therapy has a synergistic effect.

[The changes of extracellular matrix in adult degenerative nucleus pulposus cells with stiring microcarrier culture system in vitro].

OBJECTIVE: To evaluate the biological effect on the synthesis of the extracellular matrix (ECM) in the cultivation of adult degenerative nucleus pulposus cells using the stiring microcarrier system in vitro. METHODS: Thirty-four specimens were collected after intervertebral fusion operations of the patients with intervertebral disc herniation diseases from September 2005 to May 2009. The specimens were then randomly allocated into 2 groups for in vitro cultivation: monolayer culture group and microcarrier culture group. On the exponential phase, SP-ABC immunohistochemical staining and Western blot quantitative analysis were conducted in the two groups to detect the collagen type I and II. Proteoglycan contents of two groups in different growth phases were detected with (35)S-sulfate incorporation assay. RESULT: The expressions of collagen type I and II in microcarrier culture group were significantly higher than those in monolayer culture group: SP-ABC immunohistochemical staining (collagen type I: 32.5 ± 4.4 vs. 15.2 ± 1.2, t = 2.871, P < 0.01; collagen type II: 43.6 ± 4.1 vs. 23.1 ± 2.2, t = 2.375, P < 0.05); Western blot quantitative analysis (collagen type I: 0.62 ± 0.08 vs. 0.50 ± 0.06, t = 3.327, P < 0.01; collagen type II: 1.46 ± 0.08 vs. 0.86 ± 0.04, t = 2.453, P < 0.05). Nucleus pulposus cells cultivated in stiring microcarrier system showed significantly increased proteoglycan synthesis than monolayer culture group does on both exponential phase and stationary phase (exponential phase: 34 821 ± 312 vs. 21 046 ± 673, t = 2.134, P < 0.05; stationary phase: 45 134 ± 175 vs. 32 193 ± 713, t = 2.801, P < 0.01). CONCLUSIONS: The expression of collagen type I, II and proteoglycan of adult degenerative nucleus pulposus cells are positive regulated by the stiring microcarrier system, which can be used in the mass amplification of the adult degenerative nucleus pulposus cells.

[A novel rabbit disc degeneration model induced by fibronectin fragment].

OBJECTIVE: To establish a novel and useful rabbit model of lumbar disc degeneration using microinjection of fibronectin fragment (Fn-f). METHODS: Thirty-two New Zealand white rabbits underwent injection of N-terminal 30 kDa Fn-f (experimental group) or phosphate buffered saline (PBS) (control group) into the central region of L1-2, L2-3, L3-4, L4-5 discs using a 32-gauge microsyringe. Two rabbits (blank group) with no treatments were sacrificed to examine the proteoglycan synthesis of neucleus pulposus (NP) using (35)S-sulfate incorporation assay. At the 4-, 8-, 12-, and 16-week time points, the discs were examined histologically, radiographically, and with proteoglycan synthesis. RESULTS: Histology demonstrated a progressive loss of the cell numbers in NP and architecture destruction in NP and anulus fibrosus (AF) in Fn-f-injected discs over the 16-week study period. The NP regions in Fn-f-injected discs shrinked distinctly after the 4-week time point, and were not discernible with the inner AF by the 16-week time point. Protoglycan synthesis in Fn-f-injected discs decreased progressively (F = 263.241, P = 0.000). At each time point, the Fn-f-injected discs showed significantly decreased proteoglycan synthesis compared with controls (t = -27.010 - -2.833, P < 0.05). The DHI% of the Fn-f-injected discs at the 4-, 8-, 12-, and 16-week time points were 96.5% ± 1.7%, 85.6% ± 3.8%, 77.2% ± 3.5% and 65.5% ± 5.6%, respectively. Comparing with the DHI% of PBS-injected discs (97.4% ± 1.2%), the Fn-f-injected discs exihibited no significant differences in disc heights at the 4-week time point (P > 0.05), but significant decreases in disc heights at the 8-, 12-, and 16-week time points (t = -21.225 - -10.795, P < 0.01). Apparent anterior osteophytes formed at the 12-week time point and enlarged remarkablely by the 16-week time point in the experimental spines. CONCLUSIONS: Fn-f can induce a progressively degenerative process in rabbit discs which is ethical, cost-effective, reproducible, and consistent with the spontaneous degeneration in human. And it seem to be a novel and useful model for the study of disc degeneration at the molecular level.

Minimally invasive induction of an early lumbar disc degeneration model in rhesus monkeys.

STUDY DESIGN: Animal experimental study. OBJECTIVE: To establish an early and reproducible intervertebral disc (IVD) degeneration model to provide a basis for studying IVD degeneration. SUMMARY OF BACKGROUND DATA: The pathophysiology and pathogenesis of IVD degeneration, a common condition that causes low back pain, are not clearly understood. An experimental animal model of human IVD degeneration is needed. METHODS: A total of 91 IVDs were grouped as follows: group 1, percutaneous puncture using a 20-gauge needle; group 2, percutaneous puncture using a 15-gauge needle; and group 3, nonpuncture. The pre- and postpunctured IVDs were examined and graded. Hematoxylin and eosin, Masson trichrome, safranin O staining methods, and immunohistochemistry for type II collagen were performed. RESULTS: In group 1, the magnetic resonance imaging (MRI) signal intensity was grade I for all IVDs before puncture, and at the different time points after puncture. In group 2, the MRI signal intensity was grade III in the 4th week and grade IV in the 8th week after puncture. In group 3, the MRI signal intensity was grade I at all time points. In groups 1 and 2, a marked reduction in nucleus pulposus cells was observed in the 12th week. Fissures in the annulus fibrosus were observed in the 8th week. Decreased proteoglycans in the model discs was noted in the 8th and 12th week, and collagen II significantly decreased in the 12th week after puncture (P < 0.05). In group 2, the number of cells and fissures in the IVDs were decreased, with decreased proteoglycan and collagen II content in the 8th week. No changes were found in group 3. CONCLUSION: Slowly progressive and mild disc degeneration can be induced by puncture using 20-gauge needles through the IVDs, which might be suitable for investigating novel therapies for disc degeneration/pain. LEVEL OF EVIDENCE: 2.

Correction of post-traumatic thoracolumbar kyphosis using pedicle subtraction osteotomy.

The aim of this study was to retrospectively analyze and evaluate the effect of treatment employing pedicle subtraction osteotomy for chronic, posttraumatic thoracolumbar kyphosis. This study included 19 patients, 11 males and 8 females, with chronic, posttraumatic thoracolumbar kyphosis. Pre-operative kyphosis ranged from 31° to 63°. The history of trauma ranged from 8 to 63 months. All patients were treated with pedicle subtraction osteotomy. A mean 40.2° improvement in sagittal alignment was achieved with a mean correction rate of 85.8 %. Perioperative complications were encountered in two patients, one with cerebrospinal fluid leakage followed by encephalitic infection and one with a wound infection. Both were treated conservatively with antibiotics and local wound care. There were no other severe complications. The average follow-up period was 15 months (range 6-41 months). At the last follow-up, clinical symptoms and neurological function were significantly improved. Of 14 patients presenting with intractable back pain, VAS scores improved from a preoperative mean of 6.7 (range 5.0-8.0) to an average 2.0 (range 0-3.0) at final follow-up. No significant loss of correction was observed (loss of 1.7°), and solid fusion was achieved in all 19 patients. A single-stage posterior pedicle subtraction osteotomy is a safe and effective procedure for correction of posttraumatic thoracolumbar kyphosis. Using this technique, it is possible to safely obtain no greater than 55° of correction at a single level.

Biological characteristics of adult degenerative nucleus pulposus cells in a three-dimensional microcarrier stirring culture system.

A major problem in reconstructing degenerative intervertebral discs is to obtain sufficient nucleus pulposus (NP) seeding cells with normal physiologic functions. The current study adopted a three-dimensional microcarrier culture system for massive cell expansion and evaluated the biological characteristics and physiological functions of the propagated adult degenerative NP cells. Isolated adult NP cells were cultured in either microcarrier stirring culturing system or traditional monolayer cultivation. The growth characteristics, proliferation, extracellular matrix secretion, and apoptosis potential were examined to evaluate the different features of the two cultivation methods. Compared to the monolayer cultivation system, the adhesion time of NP cells in the three-dimensional microcarrier culture system appeared longer with relatively transient stable growth period. MTT and (3)H-TdR assays suggested significantly elevated proliferation and higher thymidine incorporation rates in cells from microcarrier system compare to cells in the monolayer system at the exponential growth phase (p < 0.05). Western blot data complimented the immunostaining results that the NP cells in the microcarrier system expressed significantly more protein levels of both type collagens at the exponential growth phase than that in the monolayer system (p < 0.05). Further, significantly more (35)S labeled proteoglycan incorporation was noticed in the cells on the microcarriers at both the stable growth and the exponential growth phases (p < 0.05 and p < 0.01). In conclusion, the three-dimensional microcarrier stirring culture system provides a means of fast and massive propagation of NP seeding cells which maintain their normal physiological characteristics and functions.

A novel rabbit disc degeneration model induced by fibronectin fragment.

OBJECTIVE: To establish a novel and useful rabbit model of lumbar disc degeneration using microinjection of a fibronectin fragment. METHODS: Thirty-two rabbits underwent injection of N-terminal 30 kDa fibronectin fragment (Fn-f) (Group A, n=12; Group B, n=4) or phosphate buffered saline (PBS) (Group C, n=12; Group D, n=4) into the lumbar discs using a 32-gauge microsyringe. Two rabbits (Group E) with no treatment were sacrificed to examine the proteoglycan synthesis of neucleus pulposus (NP) using (35)S-sulfate incorporation assay. At the 4-, 8-, 12-, and 16-week time points, the discs were examined histologically, radiographically and with proteoglycan synthesis. RESULTS: (1) Histology demonstrated a progressive loss of cell numbers in NP and architecture disorganization in NP and annulus fibrosus (AF) over the study period. (2) Radiology: comparing with the PBS-injected discs, the Fn-f-injected discs exhibited no significant differences in disc heights at the 4-week time point, but significant decreases in disc heights at the 8-, 12-, and 16-week time points (P<0.01). Apparent anterior osteophytes formed at the 12-week time point and enlarged remarkably by the 16-week time point in the Fn-f-injected spines. (3) Protoglycan synthesis in the Fn-f-injected discs decreased progressively (P<0.01). At each time point, the Fn-f-injected discs showed significantly decreased proteoglycan synthesis compared with controls (P<0.05 or P<0.01). CONCLUSIONS: Fn-f induced a progressively degenerative process in rabbit discs, which was consistent with the spontaneous degeneration in human. Fn-f induced degeneration seemed to be a novel and useful model for the study of disc degeneration at the molecular level.

High-intensity zone (HIZ) of lumbar intervertebral disc on T2-weighted magnetic resonance images: spatial distribution, and correlation of distribution with low back pain (LBP).

OBJECTIVES: To analyze the three-dimensional distribution of high-intensity zone (HIZ) in lumbar disks and to assess the correlation between low back pain (LBP) and spatial distribution of HIZs. METHODS: Clinical records and lumbar MRIs of 623 patients (337 males and 286 females, age 50.10 ± 15.38 years) were selected and reviewed. Baseline characteristics and 3D localization were performed and recorded by two radiologists in a blind fashion. RESULTS: Among the 623 patients, 200 exhibited an HIZ in at least one disk. HIZs were more frequently seen in the inferior part of annulus fibrosus (superior-middle-inferior ratio 39:59:140, P < 0.001). One hundred and eighty-one HIZs (76.1%) occurred at L4/5 and/or L5/S1. The prevalence of multi-segmental HIZ was 16.5%. Among the 33 patients with multi-segmental HIZs, 24 exhibited HIZs in adjacent disks. The LBP rate of HIZ patients was significantly higher than that of patients who exhibited no HIZ (57.5 vs. 47.8%, P < 0.05). There was no evidence for a correlation between LBP and spatial distribution of HIZ in disk (P > 0.05). The incidence of LBP was slightly higher when the HIZ disk level was lower or when there were HIZs exhibited in more disks; however, the difference was statistically insignificant (P > 0.05). CONCLUSIONS: High-intensity zones occurred frequently at lower segments, inferior part of annulus fibrosus, and single disk.

Transplantation of gene-modified nucleus pulposus cells reverses rabbit intervertebral disc degeneration.

BACKGROUND: Intervertebral disc degeneration is the main cause of low back pain. The purpose of this study was to explore potential methods for reversing the degeneration of lumbar intervertebral discs by transplantation of gene-modified nucleus pulposus cells into rabbit degenerative lumbar intervertebral discs after transfecting rabbit nucleus pulposus cells with adeno-associated virus 2 (AAV2)-mediated connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinases 1 (TIMP1) genes in vitro. METHODS: Computer tomography (CT)-guided percutaneous annulus fibrosus injury was performed to build degenerative lumbar intervertebral disc models in 60 New Zealand white rabbits. rAAV2-CTGF-IRES-TIMP1-transfected rabbit nucleus pulposus cells were transplanted into degenerative lumbar intervertebral discs (transplantation group), phosphate-buffered saline (PBS) was injected into degenerative lumbar intervertebral discs (degeneration control group) and normal lumbar intervertebral discs served as a blank control group. After 6, 10 and 14 weeks, the disc height index (DHI) and signal intensity in intervertebral discs were observed by X-ray and magnetic resonance imaging (MRI) analysis. The expression of CTGF and TIMP1 in nucleus pulposus tissue was determined by Western blotting analysis, the synthesis efficiency of proteoglycan was determined by a (35)S-sulfate incorporation assay, and the mRNA expression of type II collagen and proteoglycan was detected by RT-PCR. RESULTS: MRI confirmed that degenerative intervertebral discs appeared two weeks after percutaneous puncture. Transgenic nucleus pulposus cell transplantation could retard the rapid deterioration of the DHI. MRI indicated that degenerative intervertebral discs were relieved in the transplantation group compared with the degeneration control group. The expression of collagen II mRNA and proteoglycan mRNA was significantly higher in the transplantation group and the blank control group compared with the degeneration control group (P < 0.05). CONCLUSIONS: CT-guided percutaneous puncture can successfully build rabbit degenerative intervertebral disc models. Both CTGF and TIMP1-transfected cell transplantation helps to maintain disc height, and promotes the biosynthesis of type II collagen and proteoglycan in intervertebral discs, reversing the degeneration of intervertebral discs.