Aortic pulsation prevents the development of ossification of anterior longitudinal ligament toward the aorta in patients with diffuse idiopathic skeletal hyperostosis (DISH) in Japanese: Results of chest CT-based cross-sectional study.

BACKGROUND: The development and etiology of diffuse idiopathic skeletal hyperostosis (DISH) were far from complete understanding. Even the precise mechanism of the development of its typical right-sided ossification of the anterior longitudinal ligament (OALL) frequently compared to 'flowing candle wax', a hallmark of DISH, remains unknown. METHODS: The participants of this study were 261 individuals (31 females and 230 males) diagnosed as DISH according to the criteria established by Resnick and Niwayama extracted from a consecutive 3013 patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years old were excluded. Chest CT data were converted to the condition suitable for bone evaluation by the software application. The positional relationship between thoracic aorta and OALL, the morphology of the OALL adjacent to the aorta and the presence of calcification of the aortic wall adjacent to the OALL were studied. RESULTS: Of 261 individuals with DISH, we found that thoracic aorta was localized adjacent to the OALL (AD-group) in 123 cases (47%), whereas 138 cases (53%) were not (NAD-group). All OALL in AD-group was localized between T6 and T12. The shape of the OALL adjacent to the aorta was either flat or concave except for one. No case showed obvious calcification of the aortic wall adjacent to the OALL in AD-group. CONCLUSIONS: The aortic pulsation might play an important role in inhibit the development of the OALL toward the aorta in DISH. It is likely that establishment of the optimal condition of the pulsation stress simulating aortic pulsation and its delivery system can achieve arresting, slowing the progression and/or changing the morphology of the ossified lesions.

Wnt signaling pathway correlates with ossification of the spinal ligament: A microRNA array and immunohistochemical study.

BACKGROUND: Ossification of the posterior longitudinal ligament or the ligamentum flavum parallels endochondral ossification. Cell differentiation at the ossification front is known to be important during this process, although the factors regulating its initiation and progression are still unclear. The purpose of this study was to identify factors important for the regulation of chondrocyte/osteoblast differentiation during spinal ossification. METHODS: Ligamentum flavum tissue was isolated from 25 patients who underwent decompressive surgery for cervical ossification of the posterior longitudinal ligament. Tissue sections were used for in vitro culture to obtain primary cells through migration methods. To identify microRNAs associated with ossification of the posterior longitudinal ligament, cultured cells were prepared from the ligamentous tissue (n = 4; continuous type) or from control ligamentous samples harvested from patients with cervical spondylosis without spinal ossification, and analyzed using a microRNA array. The ligamentous sections were also examined by immunohistochemistry for the expression of candidate microRNA target genes. RESULTS: The microRNA array identified 177 factors; 12 of which were expressed at significantly different levels in patients with ossification of the posterior longitudinal ligament compared to those in control patients. The hsa-miR-487b-3p was down-regulated in patients with ossification of the posterior longitudinal ligament, which met the false discovery rate of <0.05. This microRNA was predicted to regulate the expression of genes involved in Wnt signaling. Furthermore, immunohistochemistry of Wnt signaling proteins, including Wnt 3a, LRP5/6, and beta-catenin, revealed positive expression in mesenchymal cells and/or premature chondrocytes at the ossification front. CONCLUSION: Our results suggested that down-regulation of miR-487b-3p plays an important role in the initiation of Wnt signaling during the ossification process. Wnt signaling may regulate both chondrocyte and osteoblast differentiation and the specification of endochondral ossification in the pathogenesis of ossification of the posterior longitudinal ligament or the ligamentum flavum.

Prevalence of thoracic diffuse idiopathic skeletal hyperostosis (DISH) in Japanese: Results of chest CT-based cross-sectional study.

BACKGROUND: The epidemiology and etiology of diffuse idiopathic skeletal hyperostosis (DISH) remain obscure. To date, to the best of our knowledge, there is no study that precisely evaluated the prevalence of thoracic DISH based on computed tomography (CT) data in large number of non-operated cohort with wide age distribution. METHODS: The participants of this study were the consecutive patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years old were excluded. Chest CT data were reconstructed in the condition suitable for bone evaluation by the software application. Definitive diagnosis of DISH was determined according to the criteria established by Resnick and Niwayama. Prevalence and distribution of thoracic DISH were reviewed and the data was statistically analyzed. RESULTS: Total 3013 patients (1261 females and 1752 males) with the mean age of 65 years were recruited. The CT-based evidence of thoracic DISH was noted in 261 individuals (31 females and 230 males) (8.7%), and their mean age was 73 years. Statistical analyses revealed that thoracic DISH had a significant male preponderance. The mean age of thoracic DISH positive individuals was significantly higher than that of thoracic DISH negative individuals. There was significant difference of bone mass index (BMI) between thoracic DISH positive and negative individuals. Thoracic DISH was noted after the age of 40s with the highest distribution found at the age of 70s. No thoracic DISH localizes only higher thoracic region was found. CONCLUSIONS: The CT-based prevalence of thoracic DISH in Japanese was 8.7%. Thoracic DISH has a significant predisposition to elderly male with high BMI.

Prevalence and clinical features of sports-related lumbosacral stress injuries in the young.

BACKGROUND: Stress injuries (stress fractures and stress reactions) of the lumbosacral region are one of the causes of sports-related lower back pain in young individuals. These injuries can be detected by bone marrow edema lesion on MRI. However, little is known about the prevalence and clinical features of early stage lumbosacral stress injuries. This study aimed to evaluate the epidemiology of lumbosacral stress injuries. METHODS: A total of 312 patients (under 18 years of age) who complained of sports-related lower back pain that had lasted for ≥7 days underwent magnetic resonance imaging (MRI) scans. We reviewed patients' records retrospectively. RESULTS: MRI showed that 33.0% of the patients had lumbar stress injuries and 1.6% had sacral stress injuries. Lumbar stress injuries were more common in males than in females and were found in 30% of 13- to 18-year-old patients. About 50% of the patients that participated in soccer or track and field were diagnosed with lumbar stress injuries. No clinical patterns in the frequencies of sacral stress injuries were detected due to the low number of patients that suffered this type of injury. Plain radiography is rarely able to detect the early stage lesions associated with lumbosacral stress injuries, but such lesions can be detected in the caudal-ventral region of the pars interarticularis on sagittal computed tomography scans. Thirty-three percent of young patients that complained of sports-related lower back pain for ≥7 days had lumbar stress injuries, while 1.6% of them had sacral stress injuries. Clinicians should be aware of the existence of these injuries. MRI is useful for diagnosing lumbosacral stress injuries.

Improved quality of cartilage repair by bone marrow mesenchymal stem cells for treatment of an osteochondral defect in a cynomolgus macaque model.

BACKGROUND AND PURPOSE: Integration of repaired cartilage with surrounding native cartilage is a major challenge for successful tissue-engineering strategies of cartilage repair. We investigated whether incorporation of mesenchymal stem cells (MSCs) into the collagen scaffold improves integration and repair of cartilage defects in a cynomolgus macaque model. METHODS: Cynomolgus macaque bone marrow-derived MSCs were isolated and incorporated into type-I collagen gel. Full-thickness osteochondral defects (3 mm in diameter, 5 mm in depth) were created in the patellar groove of 36 knees of 18 macaques and were either left untreated (null group, n = 12), had collagen gel alone inserted (gel group, n = 12), or had collagen gel incorporating MSCs inserted (MSC group, n = 12). After 6, 12, and 24 weeks, the cartilage integration and tissue response were evaluated macroscopically and histologically (4 null, 4 gel, and 4 MSC knees at each time point). RESULTS: The gel group showed most cartilage-rich reparative tissue covering the defect, owing to formation of excessive cartilage extruding though the insufficient subchondral bone. Despite the fact that a lower amount of new cartilage was produced, the MSC group had better-quality cartilage with regular surface, seamless integration with neighboring naïve cartilage, and reconstruction of trabecular subchondral bone. INTERPRETATION: Even with intensive investigation, MSC-based cell therapy has not yet been established in experimental cartilage repair. Our model using cynomolgus macaques had optimized conditions, and the method using MSCs is superior to other experimental settings, allowing the possibility that the procedure might be introduced to future clinical practice.

Cytokine Profile From the Ligamentum Flavum in Patients with Ossification of the Posterior Longitudinal Ligament in the Cervical Spine.

STUDY DESIGN: Histological, immunohistochemical, and suspension array analyses of cytokine expression in human cervical ossification of the posterior longitudinal ligament (OPLL). OBJECTIVES: The aim of this study was to determine whether changes in the cytokine profile reflect the maturation of chondrocytes and osteoblasts are associated with OPLL development. SUMMARY OF BACKGROUND DATA: OPLL progresses gradually over a prolonged period and may lead to serious spinal cord complications. However, treatment methods only include conservative therapy for neurological symptoms or surgical decompression, whereas preventive therapy for OPLL remains nonexistent. METHODS: Ligamentous samples were harvested from 24 patients with OPLL who underwent spinal surgery, and five control samples from cervical spondylotic myelo/radiculopathy patients without OPLL. Tissue sections were used for immunohistochemical studies and primary cells were cultured from the ligamentous samples for cytokine profiling. Using a suspension array system, concentrations of 27 inflammatory cytokines or growth factors were measured to generate the cytokine profiles. RESULTS: Suspension array and immunoblot analysis revealed significant increments in the levels of interleukin (IL)-6, IL-1α, basic fibroblast growth factor, and RANTES in patients with OPLL. Immunohistochemical analysis further revealed that these factors were present in mesenchymal cells within the degenerative portion of the ligamentous matrix. CONCLUSION: Our findings suggest that specific changes in the cytokine profile during ossification promote osteoblast differentiation, thereby providing new insights into OPLL pathogenesis. Moreover, this work supports the development of a new therapeutic method for preventing OPLL progression by regulating the cytokine profiles.Level of Evidence: 3.

Incidence of Cranial Adjacent Segment Disease after Posterior Lumbar Interbody Fusion Using the Cortical Bone Trajectory Technique for the Treatment of Single-Level Degenerative Lumbar Spondylolisthesis; More than a 2-Year Follow-Up.

INTRODUCTION: Posterior lumbar interbody fusion (PLIF) is a widely used effective, safe, and established treatment for degenerative spinal disorders. Adjacent segment disease (ASD) is one of the serious concerns governing the clinical results following spinal fusion surgery. Cortical bone trajectory (CBT) is an alternative and less-invasive technique for lumbar pedicle screw placement. Its unique medial and caudal entry point has the potential to prevent an iatrogenic facet joint violence leading to the ASD; however, the incidence of ASD following PLIF using the CBT technique (CBT-PLIF) remains unknown. METHODS: Among patients surgically treated with CBT-PLIF in our institute, 52 consecutive patients (13 males, 39 females) with single-level degenerative lumbar spondylolisthesis (DLS) who were followed up for at least 24 months were exclusively enrolled. Their clinical and radiological features, including the incidence of radiographical and symptomatic ASD and significantly associated factor for the developing radiographical ASD, were retrospectively measured. RESULTS: In the present study, we could confirm significant neurological improvement and reduction of the spondylolisthesis with mean follow-up period of 43 months. Radiographical and symptomatic ASD was observed in 14 (27%) and 2 (3.8%) cases, respectively. We compared these two groups and found that the latest lumbar lordosis was significantly different between the two groups, but not in age, body mass index, and Japan Orthopaedic Association score. Two patients with symptomatic ASD required additional surgical treatment around 1 year following the initial surgery. CONCLUSIONS: The present study, even though it is preliminary, revealed that CBT-PLIF can achieve a neurological improvement and an effective reduction of spondylolisthesis for the treatment of single-level DLS. The CBT technique is capable of reducing the incidence of ASD compared with the traditional technique; however, we must keep in mind that appropriate postoperative lumbar lordosis should be achieved. Larger, longer-term follow-up studies are required to elucidate the clinical output of CBT-PLIF.

In-advance trans-medullary stimulation of bone marrow enhances spontaneous repair of full-thickness articular cartilage defects in rabbits.

Mesenchymal stromal cells (MSCs), especially those lying close to cartilage defects, are an important cell source for cartilage regeneration. We hypothesize that a larger number of MSCs might become available, if the bone marrow in the immediate vicinity of the subchondral bone is stimulated for MSCs in advance of the creation of cartilage defects. A trans-medullary passage-way reaching the immediate vicinity of the subchondral bone was created 4 days prior to the creation of cartilage defects. In another setting, basic fibroblast growth factor (bFGF) was administered through the trans-medullary passage-way in order to augment the stimulation of MSCs. The rabbits were killed at various times after the creation of cartilage defects. Triple staining of bromodeoxyuridine (BrdU), CD44 and CD45 and histological evaluation were subsequently performed. A considerable proportion of the proliferating cells were identified as bone-marrow-derived MSCs. Enumeration of BrdU-positive cells demonstrated that trans-medullary stimulation, especially with bFGF, increased the number of proliferating cells. The histological grading score of trans-medullary stimulation with bFGF group was superior to that of the other groups. Thus, in-advance stimulation of the bone marrow effectively increases the number of proliferating cells. The putative progenitor cells for chondrocytes stimulated thereby are likely to be recruited to the osteochondral defects at the appropriate time, contributing to the repair of full-thickness articular cartilage defects at the early follow-up time point.

Hemiparesis in spontaneous spinal epidural haematoma: a potential stroke imitator.

Spontaneous spinal epidural haematoma (SSEH) is a rare condition that requires urgent surgical intervention in order to prevent permanent neurological deficit. SSEH commonly presents as a paraparesis or tetraparesis. SSEH presenting as a hemiparesis is less common and in such situations, it can be mistaken for a cerebrovascular accident (CVA). Thrombolytic or anticoagulant treatment for CVA can potentially worsen the neurological deficit. We report one such case of SSEH misdiagnosed as a CVA. Treatment with tissue plasminogen activator led to worsening of his condition. On a subsequent cervical spine MRI, an epidural haematoma extending from C3 to C5 was detected and treated with laminectomy and evacuation. Surgical intervention led to significant improvement from American Spinal Injury Association Scale (ASIA) B to ASIA E. Presence of clinical features such as Horner's syndrome, Brown-Sequard syndrome and the absence of cranial nerve palsies in acute hemiparesis are indicative of SSEH rather than CVA.

Novel Landmark for Cervical Pedicle Screw Insertion Point from Computed Tomography-Based Study.

STUDY DESIGN: Cross-sectional study. PURPOSE: The purpose of this study was to evaluate a novel landmark for the cervical pedicle screw insertion point. OVERVIEW OF LITERATURE: To improve the accuracy of pedicle screw placement, several studies have employed the lateral mass, lateral vertical notch, and/or inferior articular process as landmarks; however, we often encounter patients in whom we cannot identify accurate insertion points for pedicle screws using these landmarks because of degenerative changes in the facet joints. The superomedial edge of the lamina is less affected by degenerative changes, and we hypothesized that it could be a new landmark for identifying an accurate cervical pedicle screw insertion point. METHODS: A total of 327 consecutive patients, who had undergone neck computed tomographic scanning for determination of neck disease in our institute, were included in the study. At first, the line was drawn parallel to the superior border of the pedicle in the sagittal plane and parallel to the vertical body in the coronal plane. The line was moved downward in 1-mm increments to the inferior border of the pedicle. We determined whether the line passing through the superomedial edge of the lamina (termed the "N-line") was located between the superior and inferior borders of the pedicle in the sagittal plane. RESULTS: The percentages of N-lines located between the superior and inferior borders of the pedicle were 100% at C3, 100% at C4, 99% at C5, 96% at C6, and 97% at C7. The lower cervical spine has the higher N-line location. CONCLUSIONS: The N-line was frequently located at the level of the pedicle of each cervical spine in the sagittal plane. The superomedial edge of the lamina could be a new landmark for the insertion point of the cervical pedicle screw.

Short-Term Clinical Result of Cortical Bone Trajectory Technique for the Treatment of Degenerative Lumbar Spondylolisthesis with More than 1-Year Follow-Up.

STUDY DESIGN: Retrospective follow-up study on the result of surgical treatment for patients with degenerative lumbar spondylolisthesis (DLS) using cortical bone trajectory (CBT) technique. PURPOSE: To evaluate the capability of CBT to manage patients with DLS. OVERVIEW OF LITERATURE: CBT is a recently advocated, novel, less-invasive technique of lumbar pedicle screw, which provides enhanced screw purchase by maximizing the thread contact with higher density bone surface. Despite the frequent use of CBT technique in the lumbar spine surgery, little is known of the capability of this technique to manage patients with DLS. METHODS: Thirty two consecutive patients (5 males, 27 females) surgically treated with single-level DLS in our institute using CBT were included. All patients were followed up at least 12 months (mean 24 months). Their clinical and radiological features were measured. RESULTS: Good leg pain relief was achieved in all patients. The mean postoperative percentage slip demonstrated significant reduction with significant neurological recovery when compared with preoperative percentage slip, and it was maintained until the latest follow-up. Loss of correction of more than 3 mm during the follow-up period was observed in 3 cases. Surgical site infection was observed in one case; however, pull-out of PSs or neurological deterioration was not found. No patient needed additional surgery during the follow-up period. CONCLUSIONS: These preliminary results confirmed that CBT is useful for the treatment for patients with DLS. This technique allows good reduction of spondylolisthesis and neurological improvement.

Navigated Pin-Point Approach to Osteoid Osteoma Adjacent to the Facet Joint of Spine.

Osteoid osteoma (OO) is a benign osteoblastic tumor. Its curative treatment is complete removal of the nidus, where intraoperative localization of the nidus governs clinical results. However, treatment can be difficult since the lesion is often invisible over the bony surface. Accordingly, establishment of an ideal less invasive surgical strategy for spinal OO remains yet unsettled. We illustrate the efficacy of a computed tomography (CT)-based navigation system in excising OO located adjacent to the facet joint of spine. In our 2 cases, complete and pin-point removal of the nidus located close to the facet joint was successfully achieved, without excessive removal of the bone potentially leading to spinal instability and possible damage of nearby neurovascular structures. We advocate a less invasive approach to spinal OO, particularly in an environment with an available CT-based navigation system.

Atraumatic Occult Odontoid Fracture in Patients with Osteoporosis-Associated Thoracic Kyphotic Deformity: Report of a Case and Review of the Literature.

Anderson type II odontoid fractures are reported to be the most common injury of the odontoid process in patients over the age of 65. However, atraumatic occult Anderson type III odontoid fractures have been rarely described and remain a diagnostic challenge. In the present report, we illustrate a 78-year-old female with osteoporosis-associated marked thoracic kyphotic deformity who developed atraumatic Anderson type III occult odontoid fracture and raise awareness of this condition. Anteroposterior and lateral standard radiographs of cervical spine failed to disclose odontoid fracture. Magnetic resonance imaging demonstrated intensity changes of the axis. Subsequent computed tomography clearly demonstrated Anderson type III odontoid fracture. Conservative treatment achieved complete bone union without neurological deteriorations. At 3-year follow-up, the patient was doing well without neurological and radiological deteriorations. Even if the patients have no traumatic event, we have to keep odontoid fractures in our mind as one of the differential diagnoses when we encounter elderly patients with neck pain, especially in patients with osteoporosis-associated marked thoracic kyphotic deformity.

Long-term clinical outcome of sacral chondrosarcoma treated by total en bloc sacrectomy and reconstruction of lumbosacral and pelvic ring using intraoperative extracorporeal irradiated autologous tumor-bearing sacrum: a case report with 10 years follow-up.

BACKGROUND CONTEXT: Primary malignant tumors of the sacrum are rare. Chondrosarcoma is one of the common malignant tumors arising from the sacrum. Chondrosarcoma is often invasive, and there is a high propensity for local recurrence. Surgical resection is often the only effective treatment; however, the treatment of malignant sacral tumors can be challenging, both because of the anatomy of the spinopelvic complex and the frequently large tumor size. PURPOSE: We report a case of sacral chondrosarcoma that was successfully treated by total en bloc sacrectomy and reconstruction of the lumbosacral and pelvic ring using intraoperative extracorporeal irradiated autologous tumor-bearing sacrum. STUDY DESIGN: A case report with 10 years follow-up. METHODS: A 51-year-old man presented with right lower leg pain. Plain radiographs and computed tomography (CT) showed an osteolytic lesion at the sacrum that extended to the sacroiliac joint. Magnetic resonance imaging demonstrated that the tumor mass was localized from S1 to S2 with an epidural lesion at L5-S1 disc level. Histopathologic evaluation by open biopsy revealed that the lesion was chondrosarcoma. Total en bloc sacrectomy of the tumor-bearing sacrum was performed. The removed tumor-bearing sacrum was extracorporeally irradiated at 200 Gy during the operation and returned to the original position as a bone graft and fixed with instruments thereafter. RESULTS: We needed two revision surgeries during the first 3 years because of the implant failures; however, 10 years after the initial surgery, CT revealed that the irradiated sacrum had remodeled into living bone and integrated with surrounding iliac bone without radiological evidence of tumor recurrence. The patient ambulates without any support and there was no clinical and radiological evidence of tumor recurrence. CONCLUSIONS: The advantages of our method include the availability of high dose of radiation because of extracorporeal irradiation, excellent fit between graft and host bone, reduction of the dead space, no immunological rejection, no need for a bone bank, availability of the sacrum not only for the augmentation of the large defect but also for the scaffold for the other bone grafts. Our report is of only one case; however, we consider that it could be one option for the treatment of sacral malignant bone tumors, such as chondrosarcoma.

Prevalence, distribution, and morphology of thoracic ossification of the posterior longitudinal ligament in Japanese: results of CT-based cross-sectional study.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: To gain an insight into the prevalence, morphology, and distribution of thoracic ossification of the posterior longitudinal ligament of the spine (T-OPLL) by computed tomography (CT) and review of the literature. SUMMARY OF BACKGROUND DATA: The epidemiology and cause of T-OPLL remains obscure. To date, to the best of our knowledge, there is no study that has comprehensively evaluated the thoracic spine by CT to assess the prevalence, distribution, and morphology of T-OPLL in a sufficiently large size of sample with wide distribution of age. METHODS: The participants of this study were the patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years were excluded. Prevalence, distribution, and morphology of T-OPLL were reviewed. RESULTS: A total of 3013 patients (1261 females and 1752 males) with the mean age of 65 years were recruited. The CT-based evidence of T-OPLL was noted in 56 (38 females and 18 males) individuals (1.9%). Most frequently encountered type was liner type, followed by continuous cylindrical type and mixed type. Continuous waveform and beaked type were less frequently encountered. Statistical analyses revealed that T-OPLL was noted at a significantly higher rate among the females. The mean age of T-OPLL-positive males was significantly higher than that of T-OPLL-negative males. Furthermore, there was significant difference of body mass index between T-OPLL-positive and T-OPLL-negative individuals. Most of T-OPLLs were confirmed in higher or middle thoracic regions and the highest peak was found at T3-T4. T-OPLL was noted after the age of 40 years with the peak distribution found at the age of 60 years. CONCLUSION: The prevalence of T-OPLL in Japanese was 1.9%. Further studies that characterize definitive subtypes of T-OPLL on CT are warranted so as to establish possible association between clinical manifestations and size and/or subtypes of T-OPLL. LEVEL OF EVIDENCE: N/A.

Prevalence, distribution, and morphology of thoracic ossification of the yellow ligament in Japanese: results of CT-based cross-sectional study.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: To gain an insight for the prevalence, morphology, and distribution of thoracic ossification of the yellow ligament (OYL) by computed tomography (CT) and review of the literature. SUMMARY OF BACKGROUND DATA: The epidemiology and etiology of OYL remains obscure. To date, to the best of our knowledge, there is no study that comprehensively evaluated thoracic spine by CT to assess the prevalence, distribution, and morphology of OYL in a large enough sample size with wide age distribution. METHODS: The participants of this study were the patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years were excluded. Prevalence, distribution, and morphology of thoracic OYL were reviewed. RESULTS: A total of 3013 patients (1261 females and 1752 males) with the mean age of 65 years were recruited. The CT-based evidence of OYL was noted in 1094 (428 females and 666 males) individuals (36%). Single-level involvement was noted in 532 cases, whereas 562 individuals presented multilevel involvement.Statistical analyses revealed that OYL was noted at a significantly higher rate among the males (P = 0.022). Of a total of 2051 OYLs, 779 central type OYLs, a mushroom-shaped ossification localized at the center of laminae, and 1272 noncentral type OYLs were noted. Distribution of the thoracic OYL formed 2 peaks with the highest and second highest peak found at T10-T11 and T4-T5, respectively. Interestingly, OYL is noted at consistent rates after the age of 30; however, its size increased in age-dependent manners. CONCLUSION: The prevalence of thoracic OYL in Japanese was 36%. A further study disclosing the association between clinical manifestations and size and/or morphology of OYL is warranted.

Operative outcomes for cervical degenerative disease: a review of the literature.

To date, several studies were conducted to find which procedure is superior to the others for the treatment of cervical myelopathy. The goal of surgical treatment should be to decompress the nerves, restore the alignment of the vertebrae, and stabilize the spine. Consequently, the treatment of cervical degenerative disease can be divided into decompression of the nerves alone, fixation of the cervical spine alone, or a combination of both. Posterior approaches have historically been considered safe and direct methods for cervical multisegment stenosis and lordotic cervical alignment. On the other hand, anterior approaches are indicated to the patients with cervical compression with anterior factors, relatively short-segment stenosis, and kyphotic cervical alignment. Recently, posterior approach is widely applied to several cervical degenerative diseases due to the development of various instruments. Even if it were posterior approach or anterior approach, each would have its complication. There is no Class I or II evidence to suggest that laminoplasty is superior to other techniques for decompression. However, Class III evidence has shown equivalency in functional improvement between laminoplasty, anterior cervical fusion, and laminectomy with arthrodesis. Nowadays, each surgeon tends to choose each method by evaluating patients' clinical conditions.

Spatiotemporal control of proliferation and differentiation of bone marrow-derived mesenchymal stem cells recruited using collagen hydrogel for repair of articular cartilage defects.

Articular cartilage has a poor healing capacity, and cartilage regeneration is not always warranted to achieve healing. On the other hand, collagen scaffolds have been shown to support regeneration of articular cartilage defects in animal models, whereas bone morphogenetic protein-2 (BMP-2) is known to cause chondrogenic differentiation of marrow-derived mesenchymal stem cells (MSCs). The purpose of this study was to evaluate the effectiveness of intra-articular administration of BMP-2 into bone marrow-derived MSCs recruited to defects using original collagen hydrogel in rabbits at various time points. Full-thickness defects were created in both knees, then collagen hydrogels were transplanted, and BMP-2 was supplied for 1-week periods, as follows. BMP-2 was administered immediately after the operation for 1 week (BMP0-1 group), and BMP-2 was administered between weeks 1 and 2 after the operation (BMP1-2 group). BMP2 was administered between weeks 2 and 3 (BMP2-3 group). Specimens were then obtained, and bromodeoxyuridine (BrdU)-positive cells were enumerated and histologic grading was also performed. In addition, the gene expression analysis was performed using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) assays. Enumeration of BrdU-positive cells showed a significant increase in the BMP0-1 group compared with the other groups. Similarly, histologic scores in the BMP0-1 group were superior for up to 8 weeks. Finally, RT-PCR findings revealed that immediate BMP-2 administration enhanced chondrogenic differentiation.