Anmin Jin

Comparison of mesenchymal stromal cells from human bone marrow and adipose tissue for the treatment of spinal cord injury.

BACKGROUND AIMS Bone marrow and subcutaneous adipose tissue are both considered prospective sources of mesenchymal stromal cells (MSCs), which can be used in cell therapy for spinal cord injury (SCI). The present study investigated whether human adipose tissue-derived mesenchymal stromal cells (hADSCs) transplanted into a rat model of SCI would lead to similar or improved neurologic effects compared with human bone marrow-derived mesenchymal stromal cells (hBMSCs). METHODS hADSCs and hBMSCs were isolated from five adult donors. These MSCs were characterized using flow cytometry, immunocytochemistry, real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Immediately after SCI, 2 × 10(5) hBMSCs or hADSCs were injected into the injured spinal cord. Locomotor function, cell survival and differentiation, spinal cord tissue morphology and brain-derived neurotrophic factor (BDNF) expression were compared between groups. RESULTS hADSCs and hBMSCs showed similar surface protein expression, and hADSCs showed higher proliferative activity with higher expression of vascular endothelial cell growth factor, hepatocyte growth factor and BDNF than hBMSCs. After transplant, both hADSCs and hBMSCs migrated within the injured spinal cord without differentiating into glial or neuronal elements. Administration of hADSCs was associated with marked changes in the SCI environment, with significant increases in BDNF levels. This was simultaneously associated with increased angiogenesis, preserved axons, decreased numbers of ED1-positive macrophages and reduced lesion cavity formation. These changes were accompanied by improved functional recovery. CONCLUSIONS The present results suggest that hADSCs would be more appropriate for transplant to treat SCI than hBMSCs.

Anterior corpectomy versus posterior laminoplasty for multilevel cervical myelopathy: a systematic review and meta-analysis

BackgroundSurgical strategy for multilevel cervical myelopathy resulting from cervical spondylotic myelopathy (CSM) or ossification of posterior longitudinal ligament (OPLL) still remains controversial. There are still questions about the relative benefit and safety of direct decompression by anterior corpectomy (CORP) versus indirect decompression by posterior laminoplasty (LAMP).ObjectiveTo perform a systematic review and meta-analysis evaluating the results of anterior CORP compared with posterior LAMP for patients with multilevel cervical myelopathy.MethodsSystematic review and meta-analysis of cohort studies comparing anterior CORP with posterior LAMP for the treatment of multilevel cervical myelopathy due to CSM or OPLL from 1990 to December 2012. An extensive search of literature was performed in Pubmed, Embase, and the Cochrane library. The quality of the studies was assessed according to GRADE. The following outcome measures were extracted: pre- and postoperative Japanese orthopedic association (JOA) score, neurological recovery rate (RR), surgical complications, reoperation rate, operation time and blood loss. Two reviewers independently assessed each study for quality and extracted data. Subgroup analysis was conducted according to the mean number of surgical segments.ResultsA total of 12 studies were included in this review, all of which were prospective or retrospective cohort studies with relatively low quality. The results indicated that the mean JOA score system for cervical myelopathy and the neurological RR in the CORP group were superior to those in the LAMP group when the mean surgical segments were <3, but were similar between the two groups in the case of the mean surgical segments equal to 3 or more. There was no statistical difference in the surgical complication rate between the two groups when the mean surgical segments <3, but were significantly higher incidences of surgical complications and complication-related reoperation in the CORP group compared with the LAMP group in the case of the mean surgical segments equal to 3 or more. Besides, the operation time in the CORP group was longer than that in the LAMP group, and the average blood loss was significantly more in the CORP group compared with the LAMP group.ConclusionBased on the results above, anterior CORP and fusion is recommended for the treatment of multilevel cervical myelopathy when the involved surgical segments were <3. Given the higher rates of surgical complications and complication-related reoperation and the higher surgical trauma associated with multilevel CORP, however, it is suggested that posterior LAMP may be the preferred method of treatment for multilevel cervical myelopathy when the involved surgical segments were equal to 3 or more. In addition, taking the limitations of this study into consideration, it was still not appropriate to draw a strong conclusion claiming superiority for CORP or LAMP. A well-designed, prospective, randomized controlled trial is necessary to provide objective data on the clinical results of both procedures.

Anterior decompression and fusion versus posterior laminoplasty for multilevel cervical compressive myelopathy.

The optimal surgical strategy for anterior or posterior approaches remains controversial for multilevel cervical compressive myelopathy caused by multisegment cervical spondylotic myelopathy (MCSM) or ossification of the posterior longitudinal ligament (OPLL). A systematic review and meta-analysis was conducted evaluating the clinical results of anterior decompression and fusion (ADF) compared with posterior laminoplasty for patients with multilevel cervical compressive myelopathy. PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials and nonrandomized cohort studies conducted from 1990 to May 2013 comparing ADF with posterior laminoplasty for the treatment of multilevel cervical compressive myelopathy due to MCSM or OPLL. The following outcome measures were extracted: Japanese Orthopedic Association (JOA) score, recovery rate, complication rate, reoperation rate, blood loss, and operative time. Subgroup analysis was conducted according to the mean number of surgical segments. Eleven studies were included in the review, all of which were prospective or retrospective cohort studies with relatively low quality indicated by GRADE Working Group assessment. A definitive conclusion could not be reached regarding which surgical approach is more effective for the treatment of multilevel cervical compressive myelopathy. Although ADF was associated with better postoperative neural function than posterior laminoplasty in the treatment of multilevel cervical compressive myelopathy due to MCSM or OPLL, there was no apparent difference in the neural function recovery rate between the 2 approaches. Higher rates of surgery-related complication and reoperation should be taken into consideration when ADF is used for patients with multilevel cervical compressive myelopathy. The surgical trauma associated with corpectomy was significantly higher than that associated with posterior laminoplasty.

TGF-β1, in association with the increased expression of connective tissue growth factor, induce the hypertrophy of the ligamentum flavum through the p38 MAPK pathway

Hypertrophy of the ligamentum flavum (LF) is one of the key pathomechanisms of lumbar spinal stenosis (LSS). Transforming growth factor (TGF)-β1 is abundantly expressed in hypertrophied degenerative LF tissues from LSS. However, the molecular mechanisms underling the association between TGF-β1 and LF hypertrophy have not yet been fully elucidated. In this study, we investigated the important role of the mitogen-activated protein kinase (MAPK) pathway in the pathogenesis of LSS by analyzing the expression of connective tissue growth factor (CTGF) and extracellular matrix (ECM) components (collagen I and collagen III) in TGF-β1-treated LF cells. Cell growth assay revealed that TGF-β1, in association with CTGF, enhanced the the proliferation of LF cells, and we found that TGF-β1 also elevated CTGF expression and subsequently enhanced the mRNA expression of collagen I and collagen III. The increased mRNA expression levels of CTGF, collagen I and collagen III were abolished by p38 inhibitors. Both immunofluorescence imaging and western blot analysis of p38 and p-p38 revealed the increased expression and phosphorylation of p38. Silencing the expression of p38 by siRNA in LF cells decreased the protein expression of p38, p-p38 and CTGF, as well as the mRNA expression of CTGF, collagen I and collagen III. Taken together, our findings indicate that TGF-β1, in association with the increased expression of CTGF, contribute to the homeostasis of the ECM and to the hypertrophy of LF through the p38 MAPK pathway.

The morphology and clinical significance of the extraforaminal ligaments at the cervical level.

Study Design. A dissection-based study of 6 embalmed cadavers. Objective. To identify and describe the extraforaminal ligaments (EFLs) in relation to the area of the cervical intervertebral foramina and to evaluate their clinical significance. Summary of Background Data. EFLs between the lumbar spinal nerves and the tissues surrounding the intervertebral foramens have been well established. However, research work has been undertaken to describe the local anatomy of the extraforaminal part of the cervical spine; detailed anatomic studies of the EFLs of cervical nerves have not been performed. Methods. Eighty-four cervical intervertebral foramina from 6 adult embalmed cadavers were studied, and the existence and type of the EFLs were identified. The morphology, quantity, origin, insertion, and the spatial orientation of the EFLs in the cervical region were observed, and the length, width, or diameter and thickness of the ligaments were measured with a vernier caliper. Results. The EFLs could be found from the second cervical to the first thoracic spinal nerve. These ligaments could be divided into 2 types: radiating ligaments, which connected the nerve root sleeves that radiated to the transverse processes, the wall of the intervertebral foramina, and even the adjacent nerve root through the small transverse foramen; transforaminal ligaments, which originated from the anteroinferior margin of cranial transverse process and inserts in the superior margin of the anterior tubercle of caudal transverse process crossing the spinal nerve ventrally. Conclusion. Between the cervical spinal nerves and nearby structures, there are 2 types of the EFLs. The radiating ligaments may serve as a protective mechanism against traction and play an important role in the positioning of the nerves in the intervertebral foramen. However, in all probability, the transforaminal ligaments may be the underlying cause of the cervical radiculopathy. Level of Evidence: 4

The morphology and clinical significance of the dorsal meningovertebra ligaments in the cervical epidural space.

BACKGROUND CONTEXT The dural sac is anchored within the vertebral canal by connective tissue called meningovertebral ligaments in the epidural space. During flavectomy and laminectomy, inadvertent disruption of the dorsal meningovertebral ligaments may lead to dura laceration and cerebrospinal fluid (CSF) leaks. All the described dorsal meningovertebral ligaments were located in the lumbar region. A rare study is available about dorsal meningovertebral ligaments of the cervical spinal dura to the adjacent vertebrae. PURPOSE To identify and describe the dorsal meningovertebral ligaments at each cervical level and discuss their clinical significance. STUDY DESIGN A dissection-based study of 22 embalmed cadavers. METHODS The anatomy was studied in 22 whole cervical cadavers (11 females, 11 males), prepared with formaldehyde, whose ages at the time of death ranged from 55 to 78 years. The vertebral canal was divided to expose the dural sac and the spinal nerve roots. At all levels of the cervical vertebra, the morphology, quantity, origin, insertion, and spatial orientation of the dorsal meningovertebral ligaments were determined and the length, width or diameter, and thickness of the ligaments were measured with vernier calipers. RESULTS The dorsal meningovertebral ligaments in the cervical region anchored the posterior dural sac to the ligamentum flavum or laminae. The number of attachment points on the ligamentum flavum was relatively larger than that on the lamina, and the occurrence rate of dorsal meningovertebral ligaments was 100% at C1-C2 and C4--C5. The thickest ligaments were observed at the C1 and C2 vertebrae. The length of the ligaments varied from 1.50 to 35.22 mm, and the orientation of the ligaments mostly was craniocaudal. The morphology of the dorsal meningovertebral ligaments was divided into four types: strip type, cord type, grid type, and thin slice type. CONCLUSIONS In the cervical spine, the dorsal meningovertebral ligaments exist between the posterior dural sac and the ligamentum flavum or lamina. The dorsal meningovertebral ligaments may be of clinical importance to surgeons. Dissecting the dorsal meningovertebral ligaments before the cervical flavectomy and laminectomy may be an important step in reducing postoperative dura laceration and CSF leaks, which may result in significant benefits for patients and health-care organizations.

Chronic spontaneous cervicothoracic epidural hematoma in an 8-month-old infant.

Spontaneous spinal epidural hematoma is an uncommon cause of cord compression in children, especially in infants. An 8-month-old infant was admitted to our hospital for a 40-day history of paraparesis in the lower extremities. This rapidly progressed to paraparesis with an inability to move the lower extremities. MRI of the cervicothoracic spine revealed an epidural mass with compression of the spinal cord. The infant underwent C7-T3 total laminectomies. The pathology and postoperative MRI confirmed spinal epidural hematoma from a vascular malformation. We present the case to highlight the significance of recognizing this chronic spontaneous spinal epidural hematoma and discuss the diagnosis, treatment options and prognosis.

Finite element analysis of posterior cervical fixation

BACKGROUND CONTEXT Despite largely, used in the past, biomechanical test, to investigate the fixation techniques of subaxial cervical spine, information is lacking about the internal structural response to external loading. It is not yet clear which technique represents the best choice and whether stabilization devices can be efficient and beneficial for three-column injuries (TCI). HYPOTHESIS The different posterior cervical fixation techniques (pedicle screw PS, lateral mass screw LS, and transarticular screw TS) have respective indications. MATERIALS AND METHODS A detailed, geometrically accurate, nonlinear C3-C7 finite element model (FEM) had been successfully developed and validated. Then three FEMs were reconstructed from different fixation techniques after C4-C6 TCI. A compressive preload of 74N combined with a pure moment of 1.8 Nm in flexion, extension, left-right lateral bending, and left-right axial rotation was applied to the FEMs. RESULTS The ROM results showed that there were obvious significant differences when comparing the different fixation techniques. PS and TS techniques can provide better immediate stabilization, compared to LS technique. The stress results showed that the variability of von Mises stress in the TS fixation device was minimum and LS fixation device was maximum. Furthermore, the screws inserted by TS technique had high stress concentration at the middle part of the screws. Screw inserted by PS and LS techniques had higher stress concentration at the actual cap-rod-screw interface. CONCLUSIONS The research considers that spinal surgeon should first consider using the TS technique to treat cervical TCI. If PS technique is used, we should eventually prolong the need for external bracing in order to reduce the higher risk of fracture on fixation devices. If LS technique is used, we should add anterior cervical operation for acquire a better immediate stabilization.

Anatomic study and clinical significance of the dorsal meningovertebral ligaments of the thoracic dura mater.

Study Design. A dissection-based study of 18 embalmed thoracic specimens. Objective. To investigate the properties and clinical significance of the dorsal meningovertebral ligaments of the thoracic dura mater. Summary of Background Data. Previously, we performed a comprehensive anatomic study on the dorsal meningovertebral ligaments in the lumbosacral and cervical regions, whereby we concluded that the ligaments were an anatomic factor leading to dural laceration and hemorrhage during flavectomy and laminectomy. Unfortunately, thus far, no systematic anatomic study has been undertaken to examine the dorsal meningovertebral ligaments of the thoracic dura mater. Methods. Eighteen adult embalmed cadavers were studied, and the morphology, orientation, attachment site, and distribution traits of the dorsal meningovertebal ligaments were observed. In addition, the length, width, or diameter and thickness of the ligaments were measured using a Vernier caliper. Two meningovertebal ligaments were removed for histological examination. Results. In the thoracic region, the dorsal meningovertebral ligaments anchored the dura mater to the lamina or ligamentum flavum. The meningovertebral ligaments displayed a relatively even distribution along the upper thoracic region (T1–T7) and a gradual increase in frequency in the lower thoracic region from T7 to T12. The meningovertebral ligaments protrude into the dura and correspondingly become an integral part of the dura. Some ligaments are accompanied by or are attached to blood vessels. Histological examination of the meningovertebral ligaments revealed fibrous connective tissue. Conclusion. The dorsal meningovertebral ligaments exist between the dural sac and ligamentum flavum or lamina in the thoracic spine. Based on their anatomic features, meningovertebral ligaments may be one potential cause for dural laceration and epidural hemorrhage. We propose that, during thoracic flavectomy and laminectomy, the meningovertebral ligaments should first be identified and properly handled, thereby minimizing the occurrence of relevant complications. Level of Evidence: N/A