Ossification of the posterior longitudinal ligament is linked to heterotopic ossification of the ankle/foot tendons.

INTRODUCTION: Systemic osteogenesis has been speculated to be involved in the pathogenesis of ossification of the posterior longitudinal ligament (OPLL). Our purpose was to compare the radiologic prevalence and severity of heterotopic ossification in foot tendons of Japanese patients with OPLL and to determine their association with systemic heterotopic ossification. MATERIALS AND METHODS: Clinical and radiographic data of 114 patients with OPLL were collected from 2020 to 2022. Control data were extracted from a medical database of 362 patients with ankle radiographs. Achilles and plantar tendon ossification were classified as grades 0-4, and the presence of osteophytes at five sites in the foot/ankle joint was assessed by radiography. Factors associated with the presence and severity of each ossification were evaluated by multivariable logistic regression and linear regression analysis. RESULTS: The prevalence of Achilles and plantar tendon ossification (grade ≥ 2) was 4.0-5.5 times higher in patients with OPLL (40-56%) than in the controls (10-11%). The presence of Achilles tendon ossification was associated with OPLL, age, and coexisting plantar tendon ossification, and was most strongly associated with OPLL (standardized regression coefficient, 0.79; 95% confidence interval, 1.34-2.38). The severity of Achilles and plantar tendon ossification was associated with the severity of ossification of the entire spinal ligament. CONCLUSIONS: The strong association of foot tendon ossification with OPLL suggests that patients with OPLL have a systemic osteogenesis background. These findings will provide a basis for exploring new treatment strategies for OPLL, including control of metabolic abnormalities.

Posterolateral full-endoscopic debridement and irrigation is effective in treating thoraco-lumbar pyogenic spondylodiscitis, except in cases with large abscess cavities.

PURPOSE: To determine the efficacy and poor prognostic factors of posterolateral full-endoscopic debridement and irrigation (PEDI) surgery for thoraco-lumbar pyogenic spondylodiscitis. METHODS: We included 64 patients (46 men, 18 women; average age: 63.7 years) with thoracic/lumbar pyogenic spondylodiscitis who had undergone PEDI treatment and were followed up for more than 2 years. Clinical outcomes after PEDI surgery were retrospectively investigated to analyze the incidence and risk factors for prolonged and recurrent infection. RESULTS: Of 64 patients, 53 (82.8%) were cured of infection after PEDI surgery, and nine (17.2%) had prolonged or recurrent infection. Multivariate analysis demonstrated that significant risk factors for poor prognosis included a large intervertebral abscess cavity (P = 0.02) and multilevel intervertebral infections (P < 0.05). CONCLUSION: PEDI treatment is an effective, minimally invasive procedure for pyogenic spondylodiscitis. However, a large intervertebral abscess space could cause instability at the infected spinal column, leading to prolonged or recurrent infection after PEDI. In cases with a large abscess cavity with or without vertebral bone destruction, endoscopic drainage alone may have a poor prognosis, and spinal fixation surgery could be considered.

Evaluation of Surgical Indications for Full Endoscopic Discectomy at Lumbosacral Disc Levels Using Three-Dimensional Magnetic Resonance/Computed Tomography Fusion Images Created with Artificial Intelligence.

Background and Objectives: Although full endoscopic lumbar discectomy with the transforaminal approach (FED-TF) is a minimally invasive spinal surgery for lumbar disc herniation, the lumbosacral levels present anatomical challenges when performing FED-TF surgery due to the presence of the iliac bone. Materials and Methods: In this study, we simulated whether FED-TF surgery could be safely performed on a total of 52 consecutive cases with L5-S1 or L5-L6 disc herniation using fused three-dimensional (3D) images of the lumbar nerve root on magnetic resonance imaging (MRI) created with artificial intelligence and of the lumbosacral spine and iliac on computed tomography (CT) images. Results: Thirteen of the fifty-two cases were deemed operable according to simulated FED-TF surgery without foraminoplasty using the 3D MRI/CT fusion images. All 13 cases underwent FED-TF surgery without neurological complications, and their clinical symptoms significantly improved. Conclusions: Three-dimensional simulation may allow for the assessment from multiple angles of the endoscope entry and path, as well as the insertion angle. FED-TF surgery simulation using 3D MRI/CT fusion images could be useful in determining the indications for full endoscopic surgery for lumbosacral disc herniation.

Real-world persistence of twice-weekly teriparatide and factors associated with the discontinuation in patients with osteoporosis.

INTRODUCTION: A 28.2 µg twice-weekly formulation of teriparatide (2/W-TPD) was developed to provide comparably high efficacy for osteoporosis to a 56.5 µg once-weekly formulation while improving the safety and persistence rate. In the current study, we aimed to elucidate the real-world persistence of 2/W-TPD and to identify the factors associated with the discontinuation of 2/W-TPD in patients with severe osteoporosis. MATERIALS AND METHODS: This retrospective study included 90 patients who were treated with 2/W-TPD at three hospitals in Japan. Patient information was collected, including age, sex, distance to the hospital, family structure, comorbidities, previous treatment for osteoporosis, timing of the injection, side effects and duration of 2/W-TPD treatment, barthel index (BI), and bone mineral density (BMD) of the lumbar spine and femoral neck. We examined the factors influencing 2/W-TPD discontinuation using the Cox proportional hazards model. RESULTS: The 12 month completion rate of 2/W-TPD therapy was 47.5%. The Cox hazard analysis identified side effects [Hazard Ratio (HR) = 14.59, P < 0.001], low BMD of the femoral neck (HR = 0.04, P = 0.002), and morning injection (HR = 3.29, P = 0.006) as risk factors influencing the discontinuation of 2/W-TPD. Other variables, including age, did not contribute to the continuation of 2/W-TPD. CONCLUSION: One year continuation rate of 2/W-TPD was higher than the previously reported value of the once-weekly formulation in real-world setting, probably due to the lower incidence of side effects. Introducing injection of 2/W-TPD may further improve the persistence of TPD therapy for osteoporosis.

Association between obesity and ossification of spinal ligaments in 622 asymptomatic subjects: a cross-sectional study.

INTRODUCTION: Previous studies on patients with symptoms of spinal ligament ossification, including ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF), have not clarified whether obesity is a cause or consequence of these diseases and were limited by selection bias. Thus, we investigated the association between obesity and the prevalence of spinal ligament ossification in randomly selected asymptomatic subjects. MATERIALS AND METHODS: Between April 2020 and March 2021, 622 asymptomatic Japanese subjects who underwent computed tomography of neck to pelvis for medical check-up purposes were included. All subjects were divided into the following three groups: normal weight (body mass index [BMI] < 25 kg/m2), obese I (25 ≤ BMI < 30 kg/m2), and obese II (BMI ≥ 30 kg/m2). The relationship between factors affecting the presence of each spinal ligament ossification was evaluated using multivariate logistic regression analysis. RESULTS: The proportion of subjects with thoracic OPLL was significantly higher in the obese II group than in the other two groups (vs. normal weight, P < 0.001; vs. obese I, P < 0.001). BMI was associated with the prevalence of OLF, cervical OPLL, thoracic OPLL, and ossification of the anterior longitudinal ligament (OALL). BMI was most significantly associated with the prevalence of thoracic OPLL (ß, 0.28; 95% confidence interval, 0.17-0.39). CONCLUSION: BMI was associated with the prevalence of OALL, cervical OPLL, thoracic OPLL, and OLF in asymptomatic subjects, suggesting that obesity is associated with the development of heterotopic ossification of the spinal ligaments.

Metabolites Produced by a New Lactiplantibacillus plantarum Strain BF1-13 Isolated from Deep Seawater of Izu-Akazawa Protect the Intestinal Epithelial Barrier from the Dysfunction Induced by Hydrogen Peroxide.

This study aimed to investigate the protective effect of the metabolites produced by a new Lactiplantibacillus plantarum strain BF1-13, isolated from deep seawater (DSW), on the intestinal epithelial barrier against the dysfunction induced by hydrogen peroxide (H2O2) and to elucidate the mechanism underlying the effect. Protective effect of the metabolites by strain BF1-13 on the barrier function of the intestinal epithelial model treated with H2O2 was investigated by the transepithelial electrical resistance (TEER). The metabolites enhanced the Claudin-4 (CLDN-4) expression, including at the transcription level, indicated by immunofluorescence staining and quantitative RT-PCR. The metabolites also showed a suppression of aquaporin3 (AQP3) expression. Lactic acid (LA) produced by this strain of homofermentative lactic acid bacteria (LAB) had a similar enhancement on CLDN-4 expression. The metabolites of L. plantarum strain BF1-13 alleviated the dysfunction of intestinal epithelial barrier owing to its enhancement on the tight junctions (TJs) by LA, along with its suppression on AQP3-facilitating H2O2 intracellular invasion into Caco-2 cells. This is the first report on the enhancement of TJs by LA produced by LAB.

Risk factors of multidrug-resistant pyogenic spondylitis in thoraco-lumbar spine: A retrospective study of 122 cases.

BACKGROUND: The number of spinal infections has been increasing in developed countries due to the increase of aged or immunosuppressed patients. Spondylitis caused by multidrug-resistant (MDR) bacterial infection often become intractable and require long-term antibiotic therapy and multiple surgeries. Therefore, it is of great importance to understand risk factors for MDR spinal infections. The aim of this study was to elucidate the risk factors for MDR bacterial spondylitis. METHODS: A total of 122 patients (82 men, 40 women; average age: 63.8 y) with thoracic/lumbar spondylitis who underwent posterolateral full-endoscopic debridement and irrigation were included. The organisms detected by this endoscopic procedure were investigated, and the incidence and risk factors for MDR bacterial infection were retrospectively analyzed. RESULTS: Cultures of specimens obtained by endoscopic procedures were positive in 78 patients (63.9%). Among 68 isolated bacteria, MDR bacteria accounted for 47.1%. Multivariate analysis showed that significant risk factors for MDR bacterial infection included autoimmune connective tissue disease (P = 0.03) and central venous catheter (P = 0.02). The incidence of MDR bacteria in patients who were administered a broad-spectrum antibiotic for more than 1 month preoperatively was 64.0%, which was significantly higher than in patients who were administered a broad-spectrum antibiotic for less than 1 month and patients who were administered a narrow-spectrum antibiotic (P < 0.01, P < 0.01, respectively). CONCLUSIONS: The significant risk factors for MDR bacterial spondylitis included immunosuppressed conditions, such as autoimmune connective tissue disease, presence of central venous catheter, and longer administration periods of a broad-spectrum antibiotic. In patients with pyogenic spondylitis who could not be controlled with previous antibiotics and whose result of culture was negative, administration of anti-MRSA antibiotics would be considered when they have the risk factors identified in this study.

Structure Determination, Biosynthetic Origin, and Total Synthesis of Akazaoxime, an Enteromycin-Class Metabolite from a Marine-Derived Actinomycete of the Genus Micromonospora.

A new enteromycin-class antibiotic, akazaoxime (1), possessing an aldoxime functionality in place of O-methyl nitronic acid, was isolated from the cultured extract of a marine-derived actinomycete of the genus Micromonospora, along with known A-76356 (2). The structure of 1, including the absolute stereochemistry of three chiral centers, was established by comprehensive analysis of nuclear magnetic resonance (NMR) and mass spectrometry data coupled with magnetic anisotropy analysis of its phenylglycine methyl ester derivatives. The stereochemistry of 2, not determined previously, was proven to be the same as that of 1 on the basis of the similarity of their NMR and specific rotation data. Precursor feeding experiments using 13C-labeled compounds elucidated that the carbon skeletons of 1 and 2 are constructed from propionate (methylmalonate), leucine, and glycine. Establishment of the concise and flexible synthetic route to 1 enabled us to implement biological evaluation of 1 and its unnatural analogues, demonstrating weak to moderate antimicrobial activities of 1 against Gram-positive Kocuria rhizophila [minimum inhibitory concentration (MIC) of 50 µg/mL] and those of synthetic analogues against a plant pathogen Glomerella cingulata (MIC of 50 µg/mL) and a human pathogen Trichophyton rubrum (MIC of 25-50 µg/mL).

Morphological analysis of Kambin's triangle using 3D CT/MRI fusion imaging of lumbar nerve root created automatically with artificial intelligence.

PURPOSE: We developed a software program that automatically extracts a three-dimensional (3D) lumbar nerve root image from magnetic resonance imaging (MRI) lumbar nerve volume data using artificial intelligence. The aim of this study is to evaluate the morphology of Kambin's triangle in three dimensions based on an actual endoscopic transforaminal surgical approach using three-dimensional (3D) computed tomography (CT)/ magnetic resonance imaging (MRI) fusion images of the lumbar spine and nerve tissue. METHODS: Three-dimensional lumbar spine/nerve images of 100 patients (31 males and 69 females; mean age, 66.8 years) were used to evaluate the relationship between the superior articular process (SAP), exiting nerve root (ENR), and dural canal at the L2/3, L3/4, and L4/5 levels at 45° and 60° approach angles. RESULTS: The SAP-ENR distance at 60° was the greatest at L4/5 and was significantly greater at L2/3 and L4/5 than at L3/4 (P < 0.01, P < 0.01, respectively). The SAP-ENR distance at 45° was the greatest at L2/3, and it was larger in L2/3 and L4/5 than in L3/4 (P < 0.01, P < 0.01, respectively). The SAP-ENR distances at L4/5 were significantly greater at 60° than at 45° (P < 0.01). The dural canal was located within Kambin's triangle on the plane of the upper endplate of the lower vertebra at L2/3 in 41.5% of the cases and at L3/4 in 14% of the cases at 60° but not at L4/5. CONCLUSION: The 3D lumbar spine/nerve image enabled a combined assessment of the positional relationship between the SAP, ENR, and dural canal to quantify the safety zone of practical endoscopic spinal surgery using a transforaminal approach. Three-dimensional lumbar spine/nerve images could be useful for examining parameters, including bones and nerves, to ensure the safety of surgery.

Nomimicins B-D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura.

Three new tetronate-class polyketides, nomimicins B, C, and D, along with nomimicin, hereafter named nomimicin A, were isolated from the culture extract of Actinomadura sp. AKA43 collected from floating particles in the deep-sea water of Sagami Bay, Japan. The structures of nomimicins B, C, and D were elucidated through the interpretation of NMR and MS analytical data, and the absolute configuration was determined by combination of NOESY/ROESY and ECD analyses. Nomimicins B, C, and D showed antimicrobial activity against Gram-positive bacteria, Kocuria rhizophila and Bacillus subtilis, with MIC values in the range of 6.5 to 12.5 µg/mL. Nomimicins B and C also displayed cytotoxicity against P388 murine leukemia cells with IC50 values of 33 and 89 µM, respectively.

Rapidly progressive cervical myelopathy had a high risk of developing deep venous thrombosis: a prospective observational study in 289 cases with degenerative cervical spine disease.

STUDY DESIGN: A prospective observational study. OBJECTIVES: To determine the incidence of deep venous thrombosis (DVT) and to evaluate the risk factors for DVT development associated with degenerative cervical spine disease. SETTING: Hokkaido Spinal Cord Injury Center, Japan. METHODS: Between April 2008 and March 2015, patients with degenerative cervical spine disease, such as compressive myelopathy or radiculopathy, who underwent surgical treatment were prospectively assessed. Leg vein ultrasonography and D-dimer tests were performed preoperatively and at 4 days after surgery. All patients received treatment with intermittent pneumatic compression and elastic stockings for primary DVT prophylaxis. No anticoagulation medications were used for DVT prophylaxis. RESULTS: A total of 289 patients (203 males, 86 females; median age: 67 years (interquartile range, 58-76)) were included. Nine patients (3.1%) exhibited DVT during the perioperative period. All 9 cases were women who had distal DVT. The incidences of preoperative and postoperative DVT were 1.1% and 2.1%, respectively. The univariate analysis showed that statistically significant risk factors for perioperative DVT included female gender (P < 0.01), advanced age (P = 0.04), a low Japanese Orthopaedic Association score (P = 0.03), rapidly progressive myelopathy (P < 0.01), and inability to walk (P = 0.01). The multivariate analysis showed that rapidly progressive myelopathy (P = 0.04) was the most important risk factor. CONCLUSION: Female gender and rapidly progressive myelopathy are high-risk factors that predict the development of DVT during the perioperative period of cervical spine surgery. This result indicates that screening and treatment for DVT are needed in such high-risk patients.

Increased risk of symptomatic progression of instability following decompression for lumbar canal stenosis in patients receiving chronic glucocorticoids therapy.

BACKGROUND: Lumbar decompression surgery is a commonly used treatment for degenerative lumbar spinal stenosis; however, some patients develop symptomatic spinal instability following decompression surgery. The objective of this study was to reveal risk factors for delayed instability following decompression surgery for lumbar spinal stenosis. METHODS: One hundred ten patients who underwent single-level lumbar decompression between 2008 and 2014 were retrospectively reviewed. Surgical indication for decompression surgery was symptomatic lumbar canal stenosis without spondylolisthesis or with minimum spondylolisthesis (less than 4 mm translation). Patients with gross segmental motion (>10° in disc angle, >2 mm translation) on flexion-extension lumbar radiographs were excluded. Age, sex, body mass index, smoking history, diabetes mellitus, autoimmune connective tissue diseases including rheumatoid arthritis, and the use of glucocorticoids were investigated. Radiographic measurements included disc angle, disc height, slippage, facet angle, segmental motion (flexion-extension), lumbar alignment, facet effusion, and disc degeneration. Data were analyzed using multivariate forward selection stepwise logistic regression, chi-square tests, and Student t-test. RESULTS: Six of 110 patients (5.5%) developed symptomatic spinal instability at the operative level and underwent spinal fusion surgery at an average of 2.1 years postoperatively. Autoimmune connective tissue disorders and chronic use of glucocorticoids were associated with the occurrence of symptomatic spinal instability requiring spine fusion surgery, while there was no significant difference in radiographic parameters and demographic factors excluding autoimmune connective tissue diseases between reoperation and non-reoperation groups. CONCLUSIONS: Patients with autoimmune connective tissue disorders receiving chronic glucocorticoid therapy are more likely to develop symptomatic spinal instability following decompression surgery for lumbar canal stenosis without or with minimal spondylolisthesis.

A novel technique of cervical pedicle screw placement with a pilot screw under the guidance of intraoperative 3D imaging from C-arm cone-beam CT without navigation for safe and accurate insertion.

PURPOSE: The cervical pedicle screw (CPS) requires careful and accurate placement because of the critical risk for neurovascular injury. This study aimed to introduce and evaluate the safety and efficacy of a new CPS placement technique using intraoperative C-arm cone-beam CT (CBCT) and a pilot screw without navigation system. METHODS: This was a case-control study to compare the accuracy and safety of intraoperative C-arm CBCT-guided CPS placement with freehand CPS placement under lateral fluoroscopy using control data from a previous multicenter study. A total of 166 CPSs were inserted under intraoperative C-arm CBCT guidance in 48 consecutive patients (20 rheumatoid arthritis, 16 degenerative spinal disorders, 6 spinal tumor, 2 congenital deformity, 2 ossification of posterior longitudinal ligament, and 2 fracture dislocation). Accuracy and safety of CPS placement were assessed. RESULTS: The overall malposition rate was 2.4% (4 screws in grade 1: malposition by less than half-screw diameter, 0 in grade 2: malposition by more than half-screw diameter), which was significantly lower than the reported malposition rate of 14.8% in lateral fluoroscopy-guided freehand placement. There were no complications directly related to CPS insertion. The average estimated effective radiation dose per surgery was 14.7 mSv. CONCLUSIONS: The novel technique enables intraoperative adjustment of the trajectory of the CPS as well as confirmation of the CPS path before penetrating the isthmus of the pedicle, resulting in accurate and safe CPS placement, which outweighs the demerits of radiation exposure. These slides can be retrieved under Electronic Supplementary Material.

Evaluation of perforated demineralized dentin scaffold on bone regeneration in critical-size sheep iliac defects.

OBJECTIVES: Regenerating critical-size bone injury is a major problem that continues to inspire the design of new graft materials. Therefore, tissue engineering has become a novel approach for targeting bone regeneration applications. Human teeth are a rich source of stem cells, matrix, trace metal ions, and growth factors. A vital tooth-derived demineralized dentin matrix is acid-insoluble and composed of cross-linked collagen with growth factors. In this study, we recycled human non-functional tooth into a unique geometric dentin scaffold, entitled perforated root-demineralized dentin matrix (PR-DDM). The aim of this study was to evaluate the feasibility of PR-DDM as the scaffold for regenerating bone in critical-size iliac defects. MATERIAL AND METHODS: Artificial macro-pores (1 mm in diameter) were added to human vital wisdom tooth after removing the enamel and pulp portions. The modified tooth was demineralized in 0.34 N HNO3 for 30 min and is referred to as PR-DDM scaffold. Critical-size defect (10 mm × 15 mm × 9 mm Ø) was created in the iliac crest of six adult sheep. The in vivo bone regeneration by the scaffold was evaluated by micro-CT, 3D micro-CT, and histological examination at 2 and 4 months post-implantation. RESULTS: PR-DDM exhibited better bone ingrowth, especially in the artificial macro-pores. The results of micro-CT and 3D micro-CT revealed good union between scaffold and native bone. New bone formation was observed in almost all portions of PR-DDM. Higher bone volume inside the scaffold was detected at 4 months compared with 2 months. New bone ingrowth was ankylosed with PR-DDM, and both osteoinduction and osteoconduction capability of PR-DDM were confirmed histologically. The ratio of new bone formation was higher at 4 months compared with 2 months by histomorphometric analysis. CONCLUSIONS: Altogether, these results demonstrated that the human tooth-derived graft material with a unique geometric structure, PR-DDM, contributed to active bone ingrowth in critical-size bone defects. This novel scaffold may have great utility in the near-future clinical application.

[An Adult Case of 22q11.2 Deletion Syndrome with Congenital Abnormalities and Neurodevelopmental Disorders, Which Remained Undiagnosed Until Presentation of Auditory Hallucinations].

22q11.2 deletion syndrome (22q11.2 DS) is characterized by cardiac defects, abnormal facial features, thymic hypoplasia, cleft palate, and hypocalcemia, including DiGeorge syndrome (DGS), velocardiofacial syndrome (VCFS), and conotruncal anomaly face (CTAF) syndrome. Psychiatric symptoms were recently shown to be very common in patients with 22q11.2 DS, prompting greater interest in this syndrome. Early diagnosis during childhood based on a con- stellation of physical features is optimal ; however, as some patients remain undiagnosed until the presentation of other symptoms in adult life, psychiatrists are well advised to familiarize themselves with basic information concerning 22q11.2 DS. A 25-year-old woman presenting with auditory hallucinations was referred to A hospital for examination and treatment. Her family history revealed both paternal and maternal rela- tives with schizophrenia. At birth, she presented a cleft palate and ventricular septum defect. She first became ambulatory at age 4 and became verbal a year later. Her intelligence quotient was estimated at around 40 and mental retardation (DSM-IV) with autistic features was diag- nosed at age 7. After graduating from a special high school, she obtained fulltime employment in a workshop. However, auditory hallucinations began disrupting her life from 22 years of age. Although olanzapine temporarily alleviated her symptoms, the resultant extrapyramidal symp- toms worsened and she was referred to A hospital again at age 25. The patient presented with micrognathia and a flat nasal root and spoke a maximum of 3 words per sentence in a very high and indistinct tone. A cardiac defect (ventricular septal defect), scoliosis, and low platelets were also observed. The diagnosis of 22qll.2 DS was confirmed using fluorescence in situ hybridization (FISH). The patient and her family were subsequently introduced to a 22q11.2 DS patients' support group. Careful genetic counseling is paramount, but the diagnosis of 22q11.2 DS can make updated information, official aid, and access to support groups available to patients and their family. Emergency complications such as seizures due to hypocalcemia can also be anticipated. The comparatively late diagnosis of 22q11.2 DS in our patient, which went undetected until the presentation of auditory hallucinations, in the context of mental retardation with autis- tic features (DSM-IV) underscores the importance of detailed clinical observation. "One rare variant" possibly points out the essence of psychiatric pathophysiology. Moreover, 22q11.2 DS has been listed as an intractable disease in Japan since 2015. When patients present with neurodevelopmental disorders and schizophrenic symptoms, we should carefully observe their physical features for clues to the possible diagnosis of 22q11.2 DS.

Effects of Multiple Intra-articular Injections of 0.5% Bupivacaine on Normal and Osteoarthritic Joints in Rats.

PURPOSE: To determine the in vivo effects of multiple local anesthetic injections of 0.5% bupivacaine on normal and osteoarthritic articular cartilage. METHODS: Rats with normal knee joints received an intra-articular injection of 0.9% saline solution or 0.5% bupivacaine in their right knees joint once a week for 5 consecutive weeks, starting 4 weeks after the beginning of the experiment. Rats were humanely killed at 8, 16, and 24 weeks. In a parallel experiment, rats underwent anterior cruciate ligament transection to induce osteoarthritic changes. These rats were subjected to the same protocol as those with normal knee joints, starting 4 weeks after the procedure. Static weight-bearing tests were performed on both hind limbs to evaluate changes in weight-bearing ability throughout the experiments. Rats were humanely killed at 8 and 16 weeks. Cell viability was assessed with confocal microscopy, using samples from the distal femur. Histologic assessment of osteoarthritis was performed using samples from the tibial plateau based on the Osteoarthritis Research Society International (OARSI) cartilage histopathology assessment system (i.e., OARSI score). RESULTS: Static weight-bearing tests showed no significant changes after intra-articular injection of saline solution or bupivacaine, and bupivacaine injection did not increase weight bearing compared with saline solution injection, regardless of whether there were osteoarthritic changes. There were also no significant differences in cell viability, cell density, or OARSI scores between the saline solution and bupivacaine groups at each time point, regardless of whether osteoarthritic changes were induced. CONCLUSIONS: This study suggested that single or intermittent intra-articular bupivacaine injections might not have deleterious effects on either osteoarthritic or normal joints. CLINICAL RELEVANCE: There is no strong evidence that intra-articular bupivacaine injection induces degenerative changes in articular cartilage. Therefore, these results may apply to normal and osteoarthritic joints.

Caspase 3 silencing inhibits biomechanical overload-induced intervertebral disk degeneration.

Intervertebral disk (IVD) degeneration causes debilitating low back pain in much of the worldwide population. No efficient treatment exists because of an unclear pathogenesis. One characteristic event early in such degeneration is the apoptosis of nucleus pulposus (NP) cells embedded in IVDs. Excessive biomechanical loading may also be a major etiology of IVD degeneration. The present study used in vitro and in vivo models of compressive loading to elucidate the underlying mechanism of IVD degeneration. In addition, we investigated whether the inhibition of apoptosis is a potential clinical therapeutic strategy for the treatment of IVD degeneration induced by biomechanical stress. A TUNEL assay showed that NP cell-agarose three-dimensional composite cultures subjected to uniaxial, unconfined, static, compressive loading exhibited a time-dependent increase in apoptosis. Western blot analysis revealed the up-regulation of several extracellular matrix-degrading enzymes and down-regulation of tissue inhibitor of metalloproteinase 1. These responses to compressive loading were all significantly inhibited by caspase 3 siRNA. In the in vivo model of compressive loading-induced IVD degeneration, a single local injection of caspase 3 siRNA significantly inhibited IVD degeneration by magnetic resonance imaging, histological findings, IHC, and TUNEL assay. The present study suggests that caspase 3 siRNA attenuates overload-induced IVD degeneration by inhibiting NP cell apoptosis and the expression of matrix-degrading enzymes.

A preclinical large animal study on a novel intervertebral fusion cage covered with high porosity titanium sheets with a triple pore structure used for spinal fusion.

PURPOSE: To evaluate the osteoconductivity and the bonding strength of the newly developed interbody cage covered with the porous titanium sheet (porous Ti cage) to vertebral bodies in a sheep model. METHODS: Twelve sheep underwent anterior lumbar interbody fusion at L2-3 and L4-5 using either the new porous Ti cages (Group-P) or conventional Ti cages with autogenous iliac bone (Group-C). The animals were euthanized at 2 or 4 months postoperatively and subjected to radiological, biomechanical, and histological examinations. RESULTS: Computed tomography analyses showed that the ratio of bone contact area in Group-P was significantly increased at 4 months compared with that at 2 months (p = 0.01). Although the ratio of bone contact area in Group-C was significantly higher than Group-P at 2 months (p < 0.001), there was no statistically significant difference between the two groups at 4 months. Biomechanical test showed that there was no significant difference in bonding strength between the two groups at either 2 or 4 months. Histological analyses revealed that the bone apposition ratio increased significantly with time in Group-P (p < 0.001). Although Group-C showed significantly higher bone apposition ratio than Group-P at 2 months (p = 0.001), there was no statistical difference between the two groups at 4 months. CONCLUSIONS: There was bone ingrowth into the porous Ti sheet, and bonding capacity of the porous Ti cage to the host bone increased with time. However, the speed of union to the bone with a porous Ti cage was marginally lower than a conventional cage along with an autogenous bone graft. Although it needs further experiment with a larger sample size, the results of the current study suggested that this material could achieve interbody fusion without the need for bone grafts.

Bone Marrow Aspirate Concentrate Combined with Ultra-Purified Alginate Bioresorbable Gel Enhances Intervertebral Disc Repair in a Canine Model: A Preclinical Proof-of-Concept Study.

Although discectomy is commonly performed for lumbar intervertebral disc (IVD) herniation, the capacity for tissue repair after surgery is limited, resulting in residual lower back pain, recurrence of IVD herniation, and progression of IVD degeneration. Cell-based therapies, as one-step procedures, are desirable for enhancing IVD repair. This study aimed to investigate the therapeutic efficacy of a combination of newly developed ultra-purified alginate (UPAL) gel and bone marrow aspirate concentrate (BMAC) implantation for IVD repair after discectomy. Prior to an in vivo study, the cell concentration abilities of three commercially available preparation kits for creating the BMAC were compared by measuring the number of bone marrow mesenchymal stem cells harvested from the bone marrow of rabbits. Subsequently, canine-derived BMAC was tested in a canine model using a kit which had the highest concentration rate. At 24 weeks after implantation, we evaluated the changes in the magnetic resonance imaging (MRI) signals as well as histological degeneration grade and immunohistochemical analysis results for type II and type I collagen-positive cells in the treated IVDs. In all quantitative evaluations, such as MRI and histological and immunohistochemical analyses of IVD degeneration, BMAC-UPAL implantation significantly suppressed the progression of IVD degeneration compared to discectomy and UPAL alone. This preclinical proof-of-concept study demonstrated the potential efficacy of BMAC-UPAL gel as a therapeutic strategy for implementation after discectomy, which was superior to UPAL and discectomy alone in terms of tissue repair and regenerative potential.

Deep learning-based detection of lumbar spinal canal stenosis using convolutional neural networks.

BACKGROUND CONTEXT: Lumbar spinal canal stenosis (LSCS) is the most common spinal degenerative disorder in elderly people and usually first seen by primary care physicians or orthopedic surgeons who are not spine surgery specialists. Magnetic resonance imaging (MRI) is useful in the diagnosis of LSCS, but the equipment is often not available or difficult to read. LSCS patients with progressive neurologic deficits have difficulty with recovery if surgical treatment is delayed. So, early diagnosis and determination of appropriate surgical indications are crucial in the treatment of LSCS. Convolutional neural networks (CNNs), a type of deep learning, offers significant advantages for image recognition and classification, and work well with radiographs, which can be easily taken at any facility. PURPOSE: Our purpose was to develop an algorithm to diagnose the presence or absence of LSCS requiring surgery from plain radiographs using CNNs. STUDY DESIGN: Retrospective analysis of consecutive, nonrandomized series of patients at a single institution. PATIENT SAMPLE: Data of 150 patients who underwent surgery for LSCS, including degenerative spondylolisthesis, at a single institution from January 2022 to August 2022, were collected. Additionally, 25 patients who underwent surgery at 2 other hospitals were included for extra external validation. OUTCOME MEASURES: In annotation 1, the area under the curve (AUC) computed from the receiver operating characteristic (ROC) curve, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were calculated. In annotation 2, correlation coefficients were used. METHODS: Four intervertebral levels from L1/2 to L4/5 were extracted as region of interest from lateral plain lumbar spine radiographs totaling 600 images were obtained. Based on the date of surgery, 500 images derived from the first 125 cases were used for internal validation, and 100 images from the subsequent 25 cases used for external validation. Additionally, 100 images from other hospitals were used for extra external validation. In annotation 1, binary classification of operative and nonoperative levels was used, and in annotation 2, the spinal canal area measured on axial MRI was labeled as the output layer. For internal validation, the 500 images were divided into each 5 dataset on per-patient basis and 5-fold cross-validation was performed. Five trained models were registered in the external validation prediction performance. Grad-CAM was used to visualize area with the high features extracted by CNNs. RESULTS: In internal validation, the AUC and accuracy for annotation 1 ranged between 0.85-0.89 and 79-83%, respectively, and the correlation coefficients for annotation 2 ranged between 0.53 and 0.64 (all p<.01). In external validation, the AUC and accuracy for annotation 1 were 0.90 and 82%, respectively, and the correlation coefficient for annotation 2 was 0.69, using 5 trained CNN models. In the extra external validation, the AUC and accuracy for annotation 1 were 0.89 and 84%, respectively, and the correlation coefficient for annotation 2 was 0.56. Grad-CAM showed high feature density in the intervertebral joints and posterior intervertebral discs. CONCLUSIONS: This technology automatically detects LSCS from plain lumbar spine radiographs, making it possible for medical facilities without MRI or nonspecialists to diagnose LSCS, suggesting the possibility of eliminating delays in the diagnosis and treatment of LSCS that require early treatment.