Association between serum interleukin-17 levels and ectopic bone formation in OPLL patients with DISH.

OBJECTIVE: To investigate the relationship between the severity and morphology of heterotopic ossification in the spinal ligaments including sacroiliac (SI) joints, and serum interleukin-17 (IL-17) levels in patients with ossification of the posterior longitudinal ligament (OPLL) with or without diffuse idiopathic skeletal hyperostosis (DISH), as well as a non-OPLL group. METHODS: A total of 103 patients with OPLL (DISH (-), n = 50; DISH (+), n = 53) and 53 age- and gender-matched controls were included. The serum levels of IL-17 were analyzed, and the severity of ectopic ossification and the morphology of ectopic bone formation were evaluated. The SI joint morphological variations were categorized into four types. RESULTS: No significant differences were found in serum IL-17 levels between the OPLL and control groups. However, the DISH (+) group showed higher IL-17 levels than the DISH (-) group, especially in female patients (p = 0.003). Additionally, IL-17 levels were positively correlated with the number of Flat vertebral units, meaning one of the characteristics of DISH ossification type (R2 = 0.199, p = 0.012). IL-17 levels in type 4 were significantly higher in the DISH (+) group than in the DISH (-) group. CONCLUSIONS: The morphological characteristics of paravertebral bone formation in the entire spine, including the SI joint, are likely associated with serum IL-17 levels in OPLL. These findings provide pathological and serological evidence of local inflammation contributing to paravertebral ossification of OPLL patients.

Therapeutic strategy for atypical ulnar fracture in long use of bisphosphonate: A systematic review.

BACKGROUND: Atypical fractures are caused by the combined effects of severe suppression of bone metabolism (SSBT) due to long-term bisphosphonate therapy and chronic repetitive bone microdamage. Atypical ulnar fractures (AUFs) due to SSBT are rare, and there is no standard treatment strategy for such fractures. The relevant literature was reviewed, and the treatment strategy for AUF is discussed. METHODS: A systematic review was conducted. All studies on ulnar fractures in individuals with a history of bisphosphonate use were included, and the data were extracted and analyzed from the perspective of the therapeutic strategy. RESULTS: Forty limbs of 35 patients were included. As for the treatment of AUF, 31 limbs were treated surgically, and conservative treatment with casting was performed for 9 limbs. The bone fusion rate was 22/40 (55.0%), and non-union was seen in all patients treated conservatively. There was a significant difference in the bone fusion rate between patients with surgical treatment and those with conservative treatment. The bone fusion rate of patients with parathyroid hormone (PTH) and surgery was 82.3% (14/17 limbs); the bone fusion rate with PTH and bone graft was 69.2% (9/13 limbs). However, there were no significant differences in the fusion rate in the groups with or without PTH, with or without bone grafting, or the combination of the two treatments. There was also no significant difference in the bone fusion rate in the groups with or without low-intensity pulsed ultrasound (LIPUS) treatment. CONCLUSIONS: Based on the literature review, surgery is necessary to achieve bone union, but surgery alone is not adequate to achieve bony union. Bone grafting and the administration of PTH and LIPUS may promote early bone fusion, but the present study did not show significant advantages of these additional treatments for bone union.

Morphological characteristics of DISH in patients with OPLL and its association with high-sensitivity CRP: inflammatory DISH.

OBJECTIVES: To characterize and clarify evidence as to whether the ectopic bone formations of DISH in patients with ossification of the posterior longitudinal ligament (OPLL) are caused by inflammatory or degenerative processes. METHODS: Whole-spine CT and serum high-sensitivity CRP (hs-CRP) levels were obtained from 182 cervical OPLL patients (DISH+, n = 104; DISH-, n = 78). In the DISH+ group, ectopic bone formations were categorized into Flat and Jaggy types, then further divided into three subgroups: group 1 (Jaggy-dominant pattern), group 2 (Equivalence of pattern) and group 3 (Flat-dominant pattern). Data were compared between the DISH+ and DISH- groups, and among the three subgroups. RESULTS: The upper thoracic spine was most affected by the Flat type, whereas the Jaggy type was more frequent in the middle and lower thoracic regions. There was no difference in hs-CRP levels between the DISH+ and DISH- groups. Among the three subgroups, hs-CRP levels in group 3 [mean (s.d.) 0.16 (0.09) mg/dl] were significantly higher than in group 1 [0.04 (0.02) mg/dl] and group 2 [0.08 (0.06) mg/dl]. Higher levels of hs-CRP were associated with a greater number of vertebral units with Flat-type formations (ß = 0.691, P < 0.0001) and with a lesser number of vertebral units with Jaggy-type formations (ß = -0.147, P = 0.036). CONCLUSION: The Flat type in DISH might be caused by an inflammatory pathogenesis rather than a degenerative process presented in the Jaggy type.

Efficacy of surgeon-directed postoperative local injection with an analgesic mixture in posterior fusion surgery for adolescent idiopathic scoliosis.

BACKGROUND: Severe postsurgical pain in posterior spinal fusion is common. Multimodality analgesia, including opioid-based patient-controlled analgesia (PCA), is commonly used, but opioid-related adverse events such as nausea and vomiting are sometimes a problem. We used a ropivacaine-epinephrine-dexamethasone mixture given as one-time local bilateral submyofascial injections at the operated levels added to conventional multimodality analgesia including PCA for postoperative pain control in one group of patients to confirm whether administration of this mixture reduced postoperative pain and opioid use status post posterior spinal fusion. METHODS: We retrospectively reviewed 67 consecutive patients who had undergone posterior fusion surgery for adolescent idiopathic scoliosis (AIS), 35 of whom were treated with conventional analgesia that consisted mainly of PCA (control group) and 32 of whom were treated with one-time submyofascial injections of a ropivacaine-epinephrine-dexamethasone mixture (submyofascial injection group) added to conventional multimodality analgesia. We compared postsurgical pain levels and the amount of opioid use over the first 48 h after surgery, as well as physical activity levels and adverse events 2 weeks after surgery. RESULTS: Postsurgical pain quantified by a numeric rating scale (1-10) in the submyofascial injection group was significantly lower than that in the control group. The amount of fentanyl use was significantly less in the submyofascial injection group at 24 h, 48 h, and all subsequent periods after surgery. In addition, Walking Recovery Time (WRT) defined as the number of days until the first event of ambulation was significantly less in the submyofascial injection group (3.3 d vs 4.1 d, P = 0.0007)). Laxative use was significantly less in the submyofascial injection group (0.3 times vs 1.3 times, P = 0.02). CONCLUSIONS: One-time submyofascial injections at the operated levels with a ropivacaine-epinephrine-dexamethasone mixture after spinal fusion surgery reduced pain, opioid consumption, and opioid-related adverse events. This technique can contribute significantly to postoperative analgesia.

A deep convolutional neural network to predict the curve progression of adolescent idiopathic scoliosis: a pilot study.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that predominantly occurs in girls. While skeletal growth and maturation influence the development of AIS, accurate prediction of curve progression remains difficult because the prognosis for deformity differs among individuals. The purpose of this study is to develop a new diagnostic platform using a deep convolutional neural network (DCNN) that can predict the risk of scoliosis progression in patients with AIS. METHODS: Fifty-eight patients with AIS (49 females and 9 males; mean age: 12.5 ± 1.4 years) and a Cobb angle between 10 and 25 degrees (mean angle: 18.7 ± 4.5) were divided into two groups: those whose Cobb angle increased by more than 10 degrees within two years (progression group, 28 patients) and those whose Cobb angle changed by less than 5 degrees (non-progression group, 30 patients). The X-ray images of three regions of interest (ROIs) (lung [ROI1], abdomen [ROI2], and total spine [ROI3]), were used as the source data for learning and prediction. Five spine surgeons also predicted the progression of scoliosis by reading the X-rays in a blinded manner. RESULTS: The prediction performance of the DCNN for AIS curve progression showed an accuracy of 69% and an area under the receiver-operating characteristic curve of 0.70 using ROI3 images, whereas the diagnostic performance of the spine surgeons showed inferior at 47%. Transfer learning with a pretrained DCNN contributed to improved prediction accuracy. CONCLUSION: Our developed method to predict the risk of scoliosis progression in AIS by using a DCNN could be a valuable tool in decision-making for therapeutic interventions for AIS.

Effect of hyperdry amniotic membrane in preventing tendon adhesion in a rabbit model.

BACKGROUND: No anti-adhesive materials are currently in clinical use for orthopaedic surgery. We developed a hyperdry amniotic membrane (HD-AM) for easy storage and transplantation as amniotic membrane. The purpose of this study was to examine the application of HD-AM to reduce peritendinous adhesions without impairing tendon healing. METHODS: We randomly divided 3 digits (2nd, 3rd, and 4th digits) from each rabbit into three groups: a tendon repair group; a tendon repair with HD-AM group (HD-AM group); and a control group (cast only). The effects of HD-AM on peritendinous adhesions and tendon healing were examined using microscopic, histological, and mechanical analyses in a rabbit flexor digitorum profundus tendon model. RESULTS: Adhesions on macroscopic evaluation of the tendon repair site were significantly smaller in the HD-AM group than in the tendon repair group. Little adhesion formation or foreign body reactions were seen by on histologic evaluation in the HD-AM group. Range of motion following tendon repair was significantly better in the HD-AM group than in the tendon repair group. Maximal tensile strength required to pull the tendon from the site of adhesion was significantly smaller in the HD-AM group than in the tendon repair group. As for tendon repair site, no significant difference was seen between the tendon repair and HD-AM groups. CONCLUSIONS: HD-AM prevented peritendinous adhesion macroscopically, pathologically, and mechanically without impairing the sutured tendon. HD-AM has already been clinically applied in neurosurgery, ophthalmology, and otolaryngology, and clinical application as an anti-adhesive materials may be achieved in the future.

Association of Ligamentum Flavum Hypertrophy with Adolescent Idiopathic Scoliosis Progression-Comparative Microarray Gene Expression Analysis.

The role of the ligamentum flavum (LF) in the pathogenesis of adolescent idiopathic scoliosis (AIS) is not well understood. Using magnetic resonance imaging (MRI), we investigated the degrees of LF hypertrophy in 18 patients without scoliosis and on the convex and concave sides of the apex of the curvature in 22 patients with AIS. Next, gene expression was compared among neutral vertebral LF and LF on the convex and concave sides of the apex of the curvature in patients with AIS. Histological and microarray analyses of the LF were compared among neutral vertebrae (control) and the LF on the apex of the curvatures. The mean area of LF in the without scoliosis, apical concave, and convex with scoliosis groups was 10.5, 13.5, and 20.3 mm2, respectively. There were significant differences among the three groups (p < 0.05). Histological analysis showed that the ratio of fibers (Collagen/Elastic) was significantly increased on the convex side compared to the concave side (p < 0.05). Microarray analysis showed that ERC2 and MAFB showed significantly increased gene expression on the convex side compared with those of the concave side and the neutral vertebral LF cells. These genes were significantly associated with increased expression of collagen by LF cells (p < 0.05). LF hypertrophy was identified in scoliosis patients, and the convex side was significantly more hypertrophic than that of the concave side. ERC2 and MAFB genes were associated with LF hypertrophy in patients with AIS. These phenomena are likely to be associated with the progression of scoliosis.

Direct Reprogramming and Induction of Human Dermal Fibroblasts to Differentiate into iPS-Derived Nucleus Pulposus-like Cells in 3D Culture.

Intervertebral disc (IVD) diseases are common spinal disorders that cause neck or back pain in the presence or absence of an underlying neurological disorder. IVD diseases develop on the basis of degeneration, and there are no established treatments for degeneration. IVD diseases may therefore represent a candidate for the application of regenerative medicine, potentially employing normal human dermal fibroblasts (NHDFs) induced to differentiate into nucleus pulposus (NP) cells. Here, we used a three-dimensional culture system to demonstrate that ectopic expression of MYC, KLF4, NOTO, SOX5, SOX6, and SOX9 in NHDFs generated NP-like cells, detected using Safranin-O staining. Quantitative PCR, microarray analysis, and fluorescence-activated cell sorting revealed that the induced NP cells exhibited a fully differentiated phenotype. These findings may significantly contribute to the development of effective strategies for treating IVD diseases.

Sacroiliac joint variation associated with diffuse idiopathic skeletal hyperostosis.

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by the ossification of vertebral bodies and peripheral entheses. However, variations in sacroiliac (SI) joint change in patients with DISH have not been fully clarified. The purpose of this study was to evaluate SI joint variation in patients with DISH in comparison with a non-DISH population. METHODS: A total of 342 SI joints in 171 patients (DISH+, n = 86; DISH-, n = 85) who had undergone lumbar spine surgery were analyzed by computed tomography examination. SI joint variations were classified into four types: Type 1, normal or tiny peripheral bone irregularity; Type 2, subchondral bone sclerosis and osteophytes formation; Type 3, vacuum phenomenon; and Type 4, bridging osteophyte and bony fusion. The type of bridging osteophyte in SI joints and the prevalence of ossification in each spinal segment from C1 to SI joint were also examined. RESULTS: The most common SI joint variation in the DISH+ group was bony fusion (Type 4), with 71.6% exhibiting anterior paraarticular bridging. On the other hand, SI joint vacuum phenomenon (Type 3) was the most frequent change (57.1%) in the DISH- group. The middle to lower thoracic spine and SI joints were highly affected in DISH and caused bony ankylosis. CONCLUSIONS: Anterior paraarticular bridging was the most common type of SI joint change in patients with DISH who underwent lumbar spine surgery. The present results regarding variations of SI joint changes in DISH should help understand the etiology of DISH.

Differential proteome analysis in adolescent idiopathic scoliosis patients with thoracolumbar/lumbar curvatures.

BACKGROUND: Although the pathogenesis of adolescent idiopathic scoliosis (AIS) remains unclear, there are little evidences of the pathogenesis in patients with thoracolumbar/lumbar AIS. The purpose of this study was to identify proteins or proteomes that may be causally related to the pathogenesis of AIS with structured thoracolumbar/lumbar curvature using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). METHODS: A total of 20 control volunteers and 61 AIS in patients with thoracolumbar/lumbar curvature were included. First, the plasma samples of each five AIS with pure thoracolumbar/lumbar curvature and control samples were subjected to 2D-DIGE analysis. Protein spots that were expressed differently by the AIS and control groups were selected and identified by nanoscale liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) analysis. To characterize the differently-expressed proteins in AIS patients, we performed functional pathway analysis using the Protein ANalysis THrough Evolutionary Relationships (PANTHER) system. Additionally, the proteins were compared between control and AIS using western blotting. Lastly, prospectively collected 15 control and 41 AIS with thoracolumbar/lumbar curvature samples were compared to the differentially expressed proteins. RESULTS: A total of 3862 ± 137 spots were detected, of which 11 spots met the criteria when compared with controls. Nine proteins were identified by nanoLC-MS/MS. Functional analysis showed the association of the proteins in AIS patients with blood coagulation using the PANTHER system. Of the proteins, vitamin D binding protein (DBP) significantly correlated with Cobb angle in thoracolumbar/lumbar curvatures. DBP expression of the prospectively collected AIS samples were significantly higher than those of controls (P < 0.05). CONCLUSIONS: This study suggests that DBP and several coagulation-related proteins may play a role in the pathogenesis of AIS. DBP appears to be a marker of severity of AIS with thoracolumbar/lumbar curvature.

Differential rod contouring on thoracolumbar/lumbar curvature in patients with adolescent idiopathic scoliosis: An analysis with intraoperative acquisition of three-dimensional imaging.

BACKGROUND: Differential rod contouring (DRC) is useful for periapical vertebral derotation and decreasing rib hump in patients with thoracic adolescent idiopathic scoliosis (AIS). However, it is unknown whether DRC in the thoracolumbar/lumbar spine also contributes to derotation. We assessed the contributions of rod contouring and of DRC to the reduction of apical axial vertebral body rotation in patients with AIS with thoracolumbar/lumbar curvatures. METHODS: Forty-five (Lenke type 3 or 4, 17; Lenke type 5 or 6, 28) were analyzed for the contribution of DRC to thoracolumbar/lumbar spinal derotation. Rod contouring was assessed by comparing the preinsertion x-ray with the post-operative CT images. Intraoperative C-arm fluoroscopic scans of the periapical vertebrae of the thoracolumbar/lumbar curve of the scoliosis (135 vertebrae) were taken post-rod rotation (RR) and post-DRC in all patients. Three-dimensional images were automatically reconstructed from the taken x-ray images. The angle of vertebral body rotation in these apical vertebrae was measured, and the contribution of DRC to apical vertebral body derotation and rib hump index (RHi) for lumbar prominence was analyzed. RESULTS: The pre-implantation convex rod curvatures of both Lenke 3/4 and 5/6 groups decreased after surgery. The mean further reductions in vertebral rotation with post-RR DRC were 3.7° for Lenke 3/4 and 4.4° for Lenke 5/6 (P < 0.01). Both changes in apical vertebral rotation and in RHi for evaluating lumbar prominence were significantly correlated with the difference between concave and convex rod curvature in preimplantation. Vertebral derotation was significantly higher in curves with a difference >20° (P < 0.05). CONCLUSIONS: DRC following rod rotation contributed substantial additional benefit to reducing vertebral rotation and decreasing lumbar prominence in thoracolumbar/lumbar scoliosis.

The effect of multiple lesions in patients with ossification of the posterior longitudinal ligament of the cervical spine.

PURPOSE: Ossification of the posterior longitudinal ligament of the cervical spine (cervical OPLL) is associated with the lesions at the thoracic and/or lumbar spine. Multiple spinal lesions cause additional neurological deficit, affecting the outcomes of cervical laminoplasty. This study aimed to clarify the effect of multiple lesions on the outcomes of cervical laminoplasty and to compare the results with data from patients without them. METHODS: From April 1981 to October 2015, 201 patients underwent laminoplasty for cervical OPLL; however, 167 patients were followed for >2 years. Twenty-four patients underwent additional surgery for multiple lesions due to spinal stenosis. The pathologies of the lesions were assessed. The patients were divided into two groups: the thoracic and thoraco-lumbar group (T-group: 8 patients) and the lumbar group (L-group: 16 patients). One-hundred patients without an additional surgery served as the control group. The maximum Japanese Orthopaedic Association (JOA) score and the most recent score for recovery was compared between the multiple and control groups. RESULTS: The maximum score and recovery rate and the score and recovery rate at the last follow-up in the multiple group were lower than those in the control group. There was no significant difference in the postoperative JOA score and recovery rate between the T-group and the L-group. CONCLUSIONS: Neurological recovery in patients with multiple lesions was poorer than in those without lesions. Therefore, special attention should be paid to cervical OPLL with multiple spinal lesions.

Clinical and imaging characteristics in patients undergoing surgery for lumbar epidural lipomatosis.

BACKGROUND: Lumbar epidural lipomatosis (LEL) is characterized by abnormal accumulation of unencapsulated adipose tissue in the spinal epidural space. Such accumulation compresses the dural sac and nerve roots, and results in various neurological findings. However, the pathophysiology of LEL remains unclear. This study examined the associations between imaging and clinical findings in detail, and investigated the mechanisms underlying symptom onset by measuring intraoperative epidural pressures in LEL. METHODS: Sixteen patients (all men; mean age, 68.8 years) were enrolled between 2011 and 2015. Mean body mass index was 26.5 kg/m2. Four cases were steroid-induced, and the remaining 12 cases were idiopathic. All patients presented with neurological deficits in the lower extremities. Cauda equina syndrome (CES) alone was seen in 8 patients, radiculopathy alone in 4, and both radiculopathy and CES (mixed CES) in 4. All patients subsequently underwent laminectomy with epidural lipomatosis resection and were followed-up for more than 1 year. We investigated the clinical course and imaging and measured epidural pressures during surgery. RESULTS: Subjective symptoms improved within 1 week after surgery. Mean Japanese Orthopaedic Association (JOA) score was 15.2 ± 2.8 before surgery, improving to 25.4 ± 2.5 at 1 year after surgery. On magnetic resonance imaging, all lipomatosis lesions included the L4-5 level. On preoperative computed tomography, saucerization of the laminae was not observed in radiculopathy cases, whereas saucerization of the posterior vertebral body was observed in all radiculopathy or mixed CES cases. Intraoperative epidural pressures were significantly higher than preoperative subarachnoid pressures. The results suggest that high epidural pressure resulting from the proliferation of adipose tissue leads to saucerization of the lumbar spine and subsequent symptoms. CONCLUSIONS: Clinical courses were satisfactory after laminectomy. In LEL, epidural pressure increases and symptoms develop through the abnormal proliferation of adipose tissue. Higher epidural pressures induce saucerization of the laminae and/or posterior vertebral body. Furthermore, the direction of proliferative adipose tissue (i.e., site of saucerization) might be related to the types of neurological symptoms.

Selection of posterior spinal osteotomies for more effective periapical segmental vertebral derotation in adolescent idiopathic scoliosis-An in vivo comparative analysis between Ponte osteotomy and inferior facetectomy alone.

BACKGROUND: Ponte osteotomy is a useful method in posterior spinal release. However, it is unclear whether Ponte osteotomy itself contributes to vertebral derotation in surgery for adolescent idiopathic scoliosis (AIS) patients compared to inferior facetectomy alone. This study aimed to assess the effect of Ponte osteotomy on the magnitude of periapical vertebral body rotation compared to inferior facetectomy alone. This study was a prospective collected data. METHODS: The study included 63 patients with AIS (Thoracic curve type, 35; thoracolumbar/lumbar curve type, 27), who underwent surgery between August 2011 and January 2015. All AIS patients underwent posterior spinal fusion with uniplanar screws and Ponte osteotomies on three periapical intervertebral segments. We measured and analyzed the flexibility of periapical intervertebral rotation pre- and post-bilateral inferior facetectomy, and post-Ponte osteotomy with our device (three times). The difference in intervertebral rotation between pre- and post-Ponte osteotomy was analyzed. RESULTS: The mean increase in angle was 5.6° for thoracic curves and 6.4° for thoracolumbar curves. The increase in angle for thoracolumbar curves was significantly larger than that for thoracic curves (P < 0.05). The more an apical region of the scoliosis was located at caudal side of spine, the more the flexibility due to Ponte osteotomy increased (P < 0.05). The significant differences of the increase in intervertebral flexibility between inferior facetectomies and Ponte osteotomies were recognized at middle thoracic and thoracolumbar regions (P < 0.005). CONCLUSIONS: Our data suggest that Ponte osteotomy has a loosening effect on periapical scoliotic curvature compared to inferior facetectomy alone. Ponte osteotomy is likely to be associated with an increase in loosening of the middle thoracic and thoracolumbar regions.

Teriparatide versus low-dose bisphosphonates before and after surgery for adult spinal deformity in female Japanese patients with osteoporosis.

PURPOSE: Complications of adult spinal deformity surgery are problematic in osteoporotic individuals. We compared outcomes between Japanese patients treated perioperatively with teriparatide vs. low-dose bisphosphonates. METHODS: Fifty-eight osteoporotic adult Japanese female patients were enrolled and assigned to perioperative teriparatide (33 patients) and bisphosphonate (25 patients) groups in non-blinded fashion. Pre- and post-operative X-ray and computed tomography imaging were used to assess outcome, and rates were compared between the groups and according to age. Pain scores and Oswestry Disability Indices (ODI) were calculated before and 2 years after surgery. RESULTS: Adjacent vertebral fractures and implant failure, fusion failure, and poor pain and ODI outcomes were significantly more common in the bisphosphonates group than the teriparatide group. CONCLUSIONS: Perioperative administration of teriparatide is more effective than that of low-dose bisphosphonates in preventing complications and maintaining fusion rates in osteoporotic Japanese females with spinal deformities undergoing surgery.

Lumbar disc degeneration progression in young women in their 20's: A prospective ten-year follow up.

BACKGROUND: Lumbar disc degeneration (LDD) is known to be the main cause of low back pain, although it is unclear how or when LDD progresses. The purpose of this study was to clarify the process and features of LDD progression in young women. METHODS: We enrolled 480 nursing students and carried out a prospective cohort study in 84 nursing students. MRI of the lumbar spine was taken once during their time as a student and again at 9.8 years (7-14) after the first MRI when they were working as nurses. The grade of LDD was determined according to Schneiderman's grade. The progression of disc degeneration was evaluated by the change in the degenerative disc disease (DDD) score (the summation of DDD score at each disc level). The subjects were divided into two groups based on MRI findings: Group A, those without disc degeneration at the first MRI (n = 58) and Group B, those showing disc degeneration on the first MRI (n = 26). We evaluated the change in DDD score and assessed the particular disc levels that showed Schneiderman's grade worsening in each group. RESULTS: At the time of the 2nd MRI, the DDD score increased from 5.6 (5-9) to 6.3 (5-11). The L5/S disc was the most frequent level showing the progression of LDD. In Group A, 18 subjects (31.0%) and in Group B, 15 subjects (57.7%) had degeneration progression (p = 0.02). CONCLUSIONS: This study revealed that 31% of the young adult subjects already had disc degeneration in 20's (time of first MRI) and the disc degeneration rapidly progressed in these subjects.

Characteristics of ossification of the spinal ligament; incidence of ossification of the ligamentum flavum in patients with cervical ossification of the posterior longitudinal ligament - Analysis of the whole spine using multidetector CT.

BACKGROUND: Ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) are characterized by replacement of ligamentous tissue by ectopic new bone formation. Although the background of both diseases might be similar, there are some differences between two diseases. Some patients have both OPLL and OLF. However, the incidence of both OPLL and OLF is still unclear and the precise lesions have not been investigated, yet. This study was conducted to evaluate OLF of the whole spine in patients with cervical OPLL and to analyze the relationship of the ossified lesions between OLF and OPLL. METHODS: One hundred seventy eight patients who were diagnosed as cervical OPLL by plain radiographs were included. CT images of the whole spine were taken. Ossified lesions were checked at each level of vertebral body and intervertebral disc. The ossification index of OPLL (OPLL OS index) was determined by the sum of the levels of vertebral bodies and intervertebral discs where OPLL existed. The same index was applied for detecting the level of OLF (OLF OS index). Age, gender and OPLL characteristics were compared between the OLF(+) group, OLF was seen at any levels of the spinal canal, and the OLF(-) group, OLF was not seen. RESULTS: The most frequent level of OPLL was at C5 vertebral level and OLF was predominant at upper and lower thoracic levels. Seventeen patients (9.6%) had OPLL and OLF at the same spinal level. The averaged OPLL OS index of the total spine in these patients was 8.7 ± 6.1, ranged from 1 to 36. The averaged OLF OS index of the total spine was 3.1 ± 2.2 (ranged from 1 to 13) in the patients who had OLF at any levels of the whole spine. One hundred fifteen patients (64.6%) with cervical OPLL had OLF at any levels of the whole spine. No relationship was found between the OPLL OS index and the OLF OS index. There was no significant difference among the data between the OLF(+) group and the OLF(-) group. CONCLUSIONS: This study demonstrated 64.6% of the patients with cervical OPLL had OLF, mainly in the thoracic spine. However, there was no relationship regarding the severity of the ossified lesions between OPLL and OLF. CT analysis of the whole spine should be carried out for the early detection of OPLL and OLF in patients with cervical OPLL.

Asymmetric Load Transmission Induces Facet Joint Subchondral Sclerosis and Hypertrophy in Patients with Idiopathic Adolescent Scoliosis: Evaluation Using Finite Element Model and Surgical Specimen.

Adolescent idiopathic scoliosis (AIS) with thoracic curvature primarily progresses from the thoracolumbar region, causing abnormal twisting and rotation of the spinal column. This results in unbalanced, asymmetric loads on each vertebrae and increased demands on the thoracic facet joints to withstand rotational stress from adjacent vertebrae. However, no studies have focused on the stress distribution on the facet joints of the thoracic spine in patients with AIS. This study aimed to investigate the mechanical loading and its distribution on the thoracic facet joints of AIS patients using finite element (FE) analysis and surgical specimens. FE models of the thoracic spine were created from a total of 13 female AIS patients (Lenke type 1, n = 4; Lenke type 2, n = 4; Lenke type 3, n = 5). A load of 200 N on the T3 vertebrae and 30 N each on the bilateral superior articular processes were applied vertically to quantify the contact force on the facet joints from T3 to T11. In addition, morphological and histological analyses were performed on the inferior articular processes obtained during surgery. FE analysis demonstrated that contact forces of the facet joint progressively increased from the mid to lower thoracic spine of the concave side, reaching a maximum around the apex. More than 91% of the load was transmitted by the facet joints at the concave side, resulting in facet joint subchondral sclerosis and hypertrophy. The apical facet joint in AIS helps counteract rotational stress between vertebrae and transfers most stress through the concave side. In conclusion, this study found that asymmetric load transfer in the facet joints leads to subchondral sclerosis and hypertrophy. These findings can enhance our understanding of the stress loading on facet joints and the resulting biological changes and help clarify the mechanisms involved in scoliosis progression. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Sacroiliac Joint Variation in Patients With Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: Ossification of the posterior longitudinal ligament (OPLL) reveals heterotopic ossification in the spinal ligament. OPLL also tends to ossify ligaments and entheses throughout the body. However, hallmarks of sacroiliac (SI) joint ossification and its variation in OPLL have not been clarified. Here, we investigated the morphological changes in SI joints in individuals with and without OPLL. METHODS: We included 240 age- and sex-matched patients (OPLL+, 120; OPLL-, 120) in the study. SI joint variations were classified into 4 types: Type 1, normal or small peripheral bone irregularity; Type 2, subchondral bone sclerosis and osteophyte formation; Type 3, vacuum phenomenon; and Type 4, bridging osteophyte and bony fusion. Type 4 was further divided into 3 subgroups as previously described. Interactions between the ossified spinal region in OPLL and morphological changes in the SI joint were evaluated. RESULTS: SI joint ankylosis occurs more frequently in patients with OPLL (51.7%) than in those without (non-OPLL) (33.3%). The SI joint vacuum phenomenon (49.2%) was the main finding in non-OPLL. SI joint ankylosis in OPLL was characterized by anterior bridging and intra-articular fusion. OPLL patients with multilevel ossification tend to develop degeneration and ankylosis of the SI joints. CONCLUSIONS: OPLL conferred a high risk of SI joint ossification compared with non-OPLL, and patients with extensive ossification had a higher rate of SI joint ankylosis. Understanding SI joint variation could help elucidate OPLL etiology and clarify the phenotypic differences in the SI joint between OPLL and other spinal disorders.