Aponeurosis discission, a low-detergent method for tissue-engineered acellular ligament scaffolds.

Detergent treatment is the most commonly used method for the decellularization of ligaments and tendon grafts. However, it is well recognized that detergent treatment can also adversely affect the extracellular matrix. This study found that discission into the aponeurosis layer of the patellar tendon (PT) before decellularization is conducive to extracting cells from the PT using a low quantity of detergent in a short time period. The acellular aponeurosis discission ligament (AADL) retains its native collagen fibril structure and mechanical properties. Moreover, the PT retained cell and tissue compatibility in vitro and in vivo. After implantation into a defective allogeneic PT, we found that the AADL healed well in the host, and its collagen structure exhibited gradual improvement 12 months after implantation with satisfactory reconstruction. IMPACT: The aponeurosis of tendons/ligaments is the main barrier to achieving complete decellularization, and it thus prevents complete recellularization for applications in tissue engineering. Aponeurosis can obstruct the removal of cell components. We found that excising the aponeurosis before decellularization allows for the removal of cellular components with a reduced amount of detergent, thus improving the biological properties of the acellular ligament. To the best of our knowledge, no similar studies have been performed. Graphical abstract.

Consensus statement on diagnosis and treatment of cervical ossification of posterior longitudinal ligament from Asia Pacific Spine Society (APSS) 2020.

PURPOSE: The study aimed to develop an evidence-based expert consensus statement on diagnosis and treatment of cervical ossification posterior longitudinal ligament (OPLL). METHOD: Delphi method was used to perform such survey, and the panel members from Asia Pacific Spine Society (APSS) 2020 were invited to answer the open-ended questions in rounds 1 and 2. Then the results were summarized and developed into a Likert-style questionnaire for voting in round 3, and the level of agreement was defined as 80%. In the whole process, we conducted a systematic literature search on evidence for each statement. RESULTS: Cervical OPLL can cause various degrees of neurological symptoms, an it's thought to be more common in Asia population. CT reconstruction is an important imaging examination to assist diagnosis and guide surgical choice. Segmental, continuous, mixed, and focal type is the most widely used classification system. The non-surgical treatment is recommended for patients with no or mild clinical symptoms, or irreversible neurological damage, or failed surgical decompression, or condition cannot tolerant surgery, or refusing surgery. As OPLL may continue to develop gradually, surgical treatment would be considered in their course inevitably. The surgical choice should depend on various conditions, such as involved levels, thickness, and type of OPLL, skill-experiences of surgeons, which are listed and discussed in the article. CONCLUSION: In this statement, we describe the clinical features, classifications, and diagnostic criteria of cervical OPLL, and review various surgical methods (such as their indications, complications), and provide a guideline on their choice strategy.

Morphometric Analysis of the Uncinate Process as a Landmark for Anterior Controllable Antedisplacement and Fusion Surgery: A Study of Radiologic Anatomy.

OBJECTIVE: This study used the uncinate process (UP) base as the landmark to measure the various distances of the interested anatomic structures to improve the practicality of anterior controllable antedisplacement and fusion (ACAF) for ossification of the posterior longitudinal ligament (OPLL). METHODS: Computed tomographic (CT) scan data of 20 OPLL patients were studied. We investigated the base distance of the UP, transverse foramen (TF) to UP base, pedicle to UP base, posterior to anterior UP, maximal width of OPLL, and width of the vertebrae-OPLL complex (VOC). RESULTS: Base distance of the UP shows an increasing trend from C3 to C7. The average base distance of the UP ranges from 14.6 mm at C3 to 22.7 mm at C7. The TF to UP distance ranges from 4.6 to 7.2 mm. The pedicle to UP distance is significantly shorter than upper levels at C7 and C6. The posterior to anterior UP ranges from -3.7 to -5.7 mm with an increasing trend from C3 to C7. The maximal width of OPLL is 13.2 mm on average. The mean width of the VOC in the ACAF cases is 16.8 mm on average. CONCLUSIONS: The results show that the UP can serve as a landmark for the location of longitudinal osteotomies in ACAF. However, preoperative measurement of CT images should be conducted for an individual dependent surgical planning of ACAF.

Evaluation of Measuring Methods of Spinal Canal Occupation Rate in Thoracic Ossification of Ligamentum Flavum.

OBJECTIVE: The degree of hypertrophy of thoracic ossification of ligamentum flavum (TOLF) is related to the severity of the myelopathy. There is no uniform measuring method to calculate the spinal canal occupation ratio (COR) of TOLF simply and effectively. The study was to determine an appropriate measuring method to calculate the COR of TOLF. METHODS: A total of 37 computed tomography cross-sectional imaging scans (bone window) from 22 patients were analyzed retrospectively in this study. The ventral side of the lamina or superior facet was selected as bottom in Method 1, and a line perpendicular to the anteroposterior diameter and on the dorsal side of the spinal canal was selected as bottom in Method 2. The maximum thickness of the bilateral ossified mass to the bottom is d1 and d2. The maximum distance from the anterior wall of the spinal canal to the bottom is d. COR of Method 1 or 2 was (d1 + d2)/2d × 100%. Standard COR values calculated by software served as controls. RESULTS: The standard COR values were <50% in 10 images, 51%-60% in 9 images, 61%-70% in 10 images, and >71% in 8 images. There was no significant difference between COR1 and COR in every range. There were significant differences between COR2 and COR in the ≤50%, 51%-60%, and 61%-70% groups but they were not statistically significant in the >70% group. CONCLUSIONS: Method 1 is a convenient and practical method to measure the COR of ossification in patients with TOLF.

Imaging grading system for the diagnosis of dural ossification based on 102 segments of TOLF CT bone-window data.

Thoracic ossification of the ligamentum flavum (TOLF) complicated with dural ossification (DO) is a severe clinical disease. The diagnosis of DO preoperatively remains challenging. The current study retrospectively analyzed imaging features of 102 segments with TOLF from 39 patients and proposed a grading system for evaluating DO risk. Logistic regression results showed that unilateral spinal canal occupational rate (UCOR), tram track signs, and C-signs were all risk factors for DO (odds ratios of 5.393, 19.734 and 72.594, respectively). In validation analyses for the TOLF-DO grading system, sensitivity was 76.0% (19/25), specificity was 91.0% (70/77), and Youden's index was 0.66. Thus, implementation of the TOLF-DO grading system has the potential to improve the diagnosis of DO.

Low miR-34a and miR-192 are associated with unfavorable prognosis in patients suffering from osteosarcoma.

BACKGROUND: p53 is a well-known tumor suppressor gene involved in malignancy. Many microRNAs (miRNAs) have recently been identified as key components of p53 signaling networks, owing to the central role of p53 in many processes, these p53-regulated miRNAs may possess important role in osteosarcoma. METHODS: The expression of six p53-related miRNAs (miR-34 family [including miR-34a, 34b and 34c], miR-31, miR-192, and miR-215) in 80 pairs of osteosarcoma and corresponding noncancerous bone tissues were estimated by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the associations of miRNAs expression with clinicopathological factors, p53 status, and survival of patients were analyzed. RESULTS: We found that among all six miRNAs, miR-34 family, -192, and -215 had decreased levels, whereas the level of miR-31 was increased (p<0.05) in tumor compared with corresponding noncancerous bone tissues, and miR-192/215 in patients with p53 positive expression was lower than those with negative p53. Kaplan-Meier analysis demonstrated that osteosarcoma patients with low miR-34a (P=0.000) and miR-192 (P=0.022) expression had poorer disease-free survival (DFS). Moreover, disease-free survival (DFS) was shorter for patients with low miR-34a and miR-192 expression (P=0.007) and the combination of low miR-192 with p53 positive expression (P=0.000). Furthermore, the multivariate analysis identified that low miR-34a expression, the combination of low miR-34a and miR-192 expression levels and the combination of low miR-192 with p53 positive were independent biomarkers of shorter DFS. CONCLUSIONS: Together, these results suggest that p53-associated miR-34a and miR-192 expression could be novel prognosis biomarkers for surgically treated osteosarcoma.

BDNF-mediated modulation of glycine transmission on rat spinal motoneurons.

BDNF has a widespread distribution in the central and peripheral nervous systems, suggesting that BDNF may play a role in the regulation of motor control. However, the direct actions of BDNF on the motoneurons and their underlying mechanisms are still largely unknown to date. Therefore, by using whole-cell patch clamp recordings, quantitative RT-PCR and immunocytochemistry, the present study was designed to investigate the effects of BDNF on electrical activity and glycinergic transmission on the motoneurons and the underlying receptor mechanism. The results reveal: (i) BDNF did not produce a direct excitatory or inhibitory effect on the motoneurons; (ii) BDNF dose-dependently increased the glycinergic transmission on the motoneurons; (iii) glycinergic transmission on motoneurons was a direct postsynaptic effect; (iv) BDNF-induced enhancement of the glycinergic transmission was mediated by the activation of TrkB receptors; and (v) BDNF and its receptors TrkB had an extensive expression in the motoneurons. These results suggest that BDNF is directly involved in the regulation of glycinergic transmission on the motoneurons through postsynaptic TrkB receptors. Considering that the glycinergic synaptic transmission of motoneurons mainly comes from Renshaw cells, the important inhibitory interneurons of spinal cord, we speculate that BDNF may play an important role in the information integration in the spinal cord and participate in the sensitivity of motoneurons.

Assessment of cauda equina syndrome progression pattern to improve diagnosis.

STUDY DESIGN: Meta-analysis of individual patient data. OBJECTIVE: To date, the progression pattern of cauda equina syndrome (CES) has not been summarized. This study assessed individual patient data from CES cases, investigated the CES progression pattern to help clinicians provide timely diagnoses. SUMMARY OF BACKGROUND DATA: Because there were few randomized controlled trials about CES, our research was based on case reports of CES with detailed medical history. METHODS: We searched English literature regarding CES in the PubMed database. We included a total of 198 publications involving 264 cases that met the inclusion criteria. The occurrence order of symptoms was determined by reviewing patients' medical histories, and the progression pattern of CES was analyzed using sequential pattern mining. Finally, we summarized and reassessed the current timing of CES diagnosis. RESULTS: Result of sequential pattern mining demonstrated that the progression process of CES could be divided into 3 stages: early stage of CES (CESE), with bilateral peripheral nerve dysfunction characterized by progressive sensory-motor defects from unilateral to bilateral in lower extremities; incomplete CES, with reduction of sphincter functions; and CES in retention, with sphincter dysfunction. Among all the cases, 81.08% (180 cases) were diagnosed at the stage of incomplete CES or CES in retention, in which 99.4% (179 cases) had experienced CESE without being diagnosed. CONCLUSION: The characteristic progressive sensory-motor CESE defects in lower extremities marked CES onset. Instead of waiting for the onset of sphincter function abnormalities, CES should be diagnosed when the CESE symptoms manifest.

Fibroblast growth factor 2 induces mesenchymal stem cells to differentiate into tenocytes through the MAPK pathway.

Mesenchymal stem cells (MSCs) differentiate into numerous different cell types and thus have therapeutic potential for tissue engineering, anti­inflammatory and immunomodulatory purposes. FGF2 may affect the biological behavior of MSCs. MSCs were transduced with either adenovirus­null vector/green fluorescent protein (GFP) or a vector encoding for the overexpression of FGF2/GFP. The expression of FGF2 was demonstrated to be significantly higher in MSC (FGF2) compared with MSC (vector) by qPCR and western blot analysis. In order to investigate the function of FGF2 in MSCs over time, it was observed that FGF2 stimulates cell proliferation and induces cell differentiation by activating the mitogen­activated protein kinase (MAPK) signaling pathway. Following blockade of the FGF2­induced activation of the extracellular signal­regulated kinase pathway by overexpression of sprouty isoforms, the marker of differentiation markedly decreased. Altogether, the results demonstrated a novel cell biological mechanism that FGF2 differentiates into tenocytes and the MAPK pathway is key in differentiation.

Brain-derived neurotrophic factor is up-regulated in severe acute cauda equina syndrome dog model.

To determine the level of brain-derived neurotrophic factor (BDNF) in experimental dog model of severe acute cauda equina syndrome, which was induced by multiple cauda equina constrictions throughout the entire lumbar (L), sacral (S) and coccygeal (Co) spinal cord and their central processes of the dorsal root ganglia neurons. Adult male mongrel dogs were randomly divided into 2 groups. The experiment group (n=4) was subjected to multiple cauda equina constrictions. The control group (n=4) was subjected to cauda equina exposure without constrictions. Level of BDNF in the spinal cord and the dorsal root ganglion cells (L7, S1-S3) was assessed 48 hours after multiple constrictions by immunohistochemical and histopathological analyses. 48 hours after multiple constrictions of cauda equina, up-regulation of BDNF within lumbosacral (L7-S3) spinal cord and dorsal root ganglion was observed in experimental group as compared to control group. Our result suggests that BDNF might play a role in the inflammatory and neuropathic pain as a result of multiple cauda equina constrictions. Regulation of BDNF level could potentially provide a therapy for treating cauda equina syndrome.

A universal pedicle screw and V-rod system for lumbar isthmic spondylolysis: a retrospective analysis of 21 cases.

OBJECTIVE: To investigate the surgical outcome of a universal pedicle screw-V rod system and isthmic bone grafting for isthmic spondylolysis. METHODS: Twenty-four patients with isthmic spondylolysis at L5 and grade 0-I spondylolisthesis (Meyerding classification) received isthmic bone graft and stabilization using the universal pedicle screw-V rod system. Back pain was evaluated using the visual analog scale (VAS) and time to bone healing, improvement in spondylolisthesis and intervertebral space height at L5/S1 and L4/L5 were assessed. RESULTS: Twenty-one patients were followed up for 24 months and included in the analysis. Back pain was markedly improved at 3 months postoperatively with a statistical difference in VAS scores compared with preoperative VAS scores (P<0.001). The VAS scores were 0 to 3 at 6 months postoperatively in all patients and no back pain was reported in all patients except 2 patients who complained of back pain after prolonged sitting. X-ray examination showed a bone graft healing time of 3 to 12 months. Grade I spondylolisthesis improved to grade 0 in 4 patients and no noticeable change was observed in the remaining 17 cases. The intervertebral space height at L5/S1 was statistically increased (P<0.05) while no statistically significant change was seen at L4/L5. There was no statistically significant difference in the ROM of the intervertebral disks of L5/S1 and L4/5 before and after surgery. CONCLUSIONS: The universal pedicle screw-V rod system and isthmic bone grafting directly repairs isthmic spondylolysis and reduces back pain, prevents anterior displacement of the diseased segment and maintains intervertebral space height, thus offering a promising alternative to current approaches for isthmic spondylolysis.

[Clinical characteristics and early effective treatment for pulmonary infection after acute cervical spinal cord injury].

OBJECTIVE: To explore the clinical characteristics and early effective treatment for pulmonary infection after acute cervical spinal cord injury. METHODS: A total of 215 inpatients with acute cervical spinal cord injury were retrospectively analyzed. Their chest radiological films and blood profiles at discharge were analyzed. The fourth generation cephalosporin was used to treat pulmonary infection as soon as admission and the antibiotics switched according to the results of sputum culture and drug sensitive test. Incision of trachea was performed and breath supported by breath machine according to respiratory condition and blood gas analysis. All patients were turned over and slapped on the back in order to excrete phlegm in time. Sometimes bronchial lavage was used to excrete phlegm. The chest radiological examinations and sputum culture were performed twice one week. Once fungal infection was definite, specific antibiotic was used to treat infection. Three-liter bas and nasal feeding were used to improve the nutrition condition. Incision of trachea was closed as soon as possible. RESULTS: Pulmonary infection of 214 patients was finally cured. Among them, 43 suffered from pulmonary closure. One patient died from severe infection of Klebsiella pneumoniae. Pulmonary infection appeared upon admission and was mostly accompanied with hyperpyrexia. The result of sputum culture revealed baumannii and the pathogen of hemoculture was Pseudomonas aeruginosa. At 3 - 4 weeks later, mycotic infection appeared. And 17 patients suffered from Klebsiella pneumoniae and one died. CONCLUSION: Pulmonary infection after acute cervical spinal cord injury is severe and occurs early. Effective antibiotics according to the result of sputum culture, turnover & back-slapping for excreting phlegm in time, expectoration training and strengthening overall nutrition are effective therapeutic measures.

Identification of risk factors for respiratory complications in upper cervical spinal injured patients with neurological impairment.

OBJECTIVE: Clinical features of respiratory complications in patients with upper cervical spine injuries (CSI) are unique due to the complex regional anatomy in the region. The objective of this study was to identify the risk factors for respiratory complications in the patients with upper CSI and cervical spinal cord injuries (C-SCI). METHODS: Ninety-two patients (out of 1593 spine injured patients) who met the inclusion criteria of upper CSI were admitted to our hospital from 1992 to 2010. Their records were retrospectively reviewed. RESULTS: Respiratory complications occurred in 16 patients (17.4%). In addition, ventilator-associated pneumonia played an important role in the respiratory complications, however, no pulmonary thromboembolism was found. Death rate in respiratory complication group (RCG, 31.3%) was significantly higher than that in non-respiratory complication group (NCG, 1.3%). In RCG, severe C-SCI (American Spinal Cord Injury Association Grades A and B, OR=34.401; 95% CI, 2.609-5.525) and hypoalbuminemia (OR=24.616; 95% CI, 1.492-6.182) were identified by logistic regression analysis as main risk factors for respiratory complications; whereas levels of neurological injury, quadriplegia, atlanto-axial fractures, smoking history, and electrolyte disturbances were not identified as risk factors (although statistically relevant to respiratory complications). CONCLUSION: Severe C-SCI and hypoalbuminemia played important roles in predicting respiratory complications among the patients with upper CSI and neurological impairment. In addition, levels of neurological injury, quadriplegia, atlanto-axial fractures, smoking history, and electrolyte disturbances are also valuable indicators for these complications. Moreover, prevention of ventilator-associated pneumonia was crucial in the treatment of these patients. However, a screening for deep venous thrombosis was seemingly unnecessary in our patients.

[Clinical observation and evaluation of reasons for pseudarthrosis after anterior cervical fusion].

OBJECTIVE: To explore the causes of pseudarthrosis and evaluate the clinical neurological function and neck subaxial symptoms after anterior cervical fusion. METHODS: A total of 412 patients were followed up with an average of 5.4 years. The bone mineral density, bone graft trimming and placement, management of endplate, smoking and neck support fixation time were observed. Japanese Orthopedic Association (JOA) score was used to evaluate the changes of neurological functions and clinical outcomes. Visual analog scale (VAS) score was used to evaluate the neck subaxial symptoms. And pseudarthrosis was examined by flexion-extension radiography. SPSS statistical software 13.0 was used to evaluate the differences of JOA and VAS scores between pseudarthrosis and control groups. RESULTS: Among them, 37 cases of pseudarthrosis were observed. There were osteoporosis (n = 30 vs n = 119), cartilage end-plate punctuate hemorrhage (n = 18 vs n = 340), 25 and 43 cases with ineffective cervical external fixation (n = 25 vs n = 43) and smoking (n = 26 vs n = 87) in pseudarthrosis and fusion groups respectively. Significant differences existed in the above-mentioned indices between two groups. However, no significant difference existed in bone graft shape between two groups. There were significant differences in JOA and VAS scores between two groups. CONCLUSION: The causes of pseudarthrosis included decreased bone density, osteoporosis, over-curette of endplate, shortness of neck support fixation time and smoking. And pseudarthrosis may influence the long-term recovery of neurological functions or it is correlated significantly with neck symptoms.

[Short-term clinical results of interspinous dynamic fixation of Coflex for the prevention of adjacent segment degeneration after lumbar fusion].

OBJECTIVE: To observe the short-term clinical results of the adjacent segment degeneration after the implantation of Coflex system at the interspinous space of adjacent segment to lumbar fusion. METHODS: Fifty patients with grade III disc (Thompson MRI classification) of adjacent segment to lumbar fusion were included and divided alternately into two groups according to the order of hospitalization from January to November 2009. Coflex system was implanted at the interspinous space of adjacent segment to lumbar fusion in 25 patients as Coflex group, the other 25 patients did not have any surgical treatment were as control group. The followed up time was 2 years. Visual analogue scale (VAS) score of low back pain, changes of disc height and motion range of adjacent segment to lumbar fusion on X-ray imaging were evaluated by independent sample t-test or paired samples t-test. RESULTS: There were 22 patients in Coflex group and 21 patients in control group were followed up 2 years post-operation. The difference of VAS score between two groups was no significance (P > 0.05). In Coflex group, the change of postoperative disc height was no significance (P > 0.05), but the motion range was significantly reduced to 47% of the preoperative value (t = 7.99, P < 0.05). In control group, the postoperative disc height decreased slightly, without significant difference to the preoperative value (P > 0.05). Between the two groups, no differences of the disc height and motion range were found before operation, but the differences of the disc height changes (t = 6.7, P < 0.05) and motion rang (t = -14.5, P < 0.05) were significant in 2 years post-operation. No complications such as Coflex system loosen, immigration and spinal process fracture were occurred. CONCLUSIONS: Coflex system can obviously limit the motion range and maintain the disc space height of adjacent segment to lumbar fusion, and prevent its degeneration in some degree.

Osteogenic scaffolds for bone reconstruction.

A highly osteogenic hybrid bioabsorbable scaffold was developed for bone reconstruction/augmentation. Through the use of a solid free-form fabrication technology, a bioabsorbable polycaprolactone (PCL) cage scaffold with a desired size and shape was produced and then filled with osteogenic bone graft particles, that is, morselized autologous bone chips. A rabbit total lamina defect model was chosen to demonstrate its efficacy in regenerating bone with a complicated anatomic shape. Both iliac bone and morselized iliac bone grafts were used in this study for comparison purposes. Serum osteocalcin and collagen type I cross-linked C-terminal telopeptide (CTx) determination showed that active bone remodeling occurred after bone grafts were implanted. X-ray images showed that the bony defects were completely filled with bone mass in all the groups with bone grafts. However, biomechanical tests showed that only the iliac bone and hybrid scaffold groups could restore the mechanical properties to the normal level after 10 weeks of implantation. A histology study showed that both iliac and hybrid scaffold groups had extensive new bone formation, and no adhesion and fibrosis were found. These results indicated that this osteogenic hybrid scaffold can be a good alternative to autologous iliac bone, because it does not need a second iliac bone-harvesting surgery, and thus the morbidity and the possible infections that are often associated with the bone harvesting surgery can be avoided.

[Current study and research progress of whiplash injury of cervical vertebrae].

Whiplash injury is a common injures in our daily lives, but the mechanism of it and the best treatment is largely unknown. The development of chronic pain and disability following whiplash injury is not uncommon and results in substantial social and economic costs. Clinical manifestation and recovery time are difference, which make it difficult for doctor diagnosis and treatment. The current study have shown that the social class, severity of collision, compensation and lawsuit, physical and psychological factors were relevant predictors for the outcome of whiplash. This article is try to overview the status quo of the whiplash injury.

[Surgical treatment strategies for severe cervicothoracic kyphosis].

OBJECTIVE: To analyze the outcomes of surgical treatment for severe cervicothoracic kyphosis. METHODS: A retrospective study was performed for a total of 7 patients with severe cervicothoracic kyphosis. There were congenital malformation (n = 5) and cervicothoracic tuberculosis (n = 2). The mean preoperative Cobb angle of kyphosis was 89.3° (range: 72 - 103°). The average JOA (Japanese Orthopedic Association) score of neurological function was 11.2 ± 1.2 points. Preoperative halo-pelvic traction was performed and maintained for 25 - 40 days according to the patient conditions. Then posterior instrumented fusion was performed. RESULTS: The average postoperative JOA score was 15.4 ± 1.6 points. The mean immediate postoperative Cobb angle was 53.4° (range: 45 - 67°). A mean correction rate of 40.2% was achieved. All patients were followed up for a mean of 18 months (range: 10 - 24). And a mean correction loss of 2.5° was observed at the final follow-up. Two patients had transient upper limb pain during distraction. There were no intra-operative or post-operative occurrences of spinal cord injury and other neurological complications. CONCLUSION: Halo-pelvic traction plus posterior spondylodesis may be a safe and effective therapy of severe cervicothoracic kyphotic deformity.