Novel Surgical Strategy for Treating Osteoporotic Vertebral Fractures with Cord Compression.

OBJECTIVES: Treatment for osteoporotic vertebral fracture (OVF) with cord compression is challenging and it usually requires surgical interventions to decompress nerves and restore spinal sequences. To describe a novel surgical strategy for treating OVFs with cord compression. METHODS: This is a single-center retrospective analysis. The inclusion criteria were Frankel grade C-E, single level T10 -L2 . Between January 2008 and December 2016, a total of 56 OVF patients (47 females and nine males, with an average age of 72 years (66-88 years), comprising of eight grade C, 23 grade D, and 25 grade E patients) were enrolled. The treatment algorithm included preoperative evaluation by MRI, extension CT, and radiography to classify the OVFs as type 1.1 (reducible, stable; n = 13), type1.2 (reducible, unstable; n = 16), type 2 (irreducible; n = 19) or type 2M (modifier; n = 8). Vertebroplasty (VP)/kyphoplasty (KP) was applied in type 1.1. VP/KP with posterior fixation and posterolateral fusion was applied in type 1.2. And additional laminectomy/osteotomy was used in type 2, except in a modifier group (2M) where same procedure as applied for type 1.2 was used. VAS, ODI, Cobb angle, Frankel functional grade, and complications were recorded. RESULTS: Thirteen cases were classified as type 1.1, 16 cases as type 1.2, 19 cases as type 2, and eight cases as type 2M. The follow-up period was 38.9 months (range, 24-108 months). All patients were followed-up in at least 24 months, in which time four patients died, two patients were lost at the last follow-up, and 50 patients completed the full study. The total VAS and ODI improved from 8 (7, 9) and 75.5% (67.2%, 80.0%) preoperatively to 2 (1, 3) and 31% (24.0%, 37.0%) on conclusion, respectively (P < 0.01). The local kyphotic angle was corrected from 22.3° (17.1°, 33. 8°) preoperatively to 10.4° (6.4°, 15.3°) on conclusion (P < 0.01). Twenty-three patients had achieved neurological recovery on conclusion (42E, 8D, P < 0.01). Asymptotic cement leakage was observed in 17/56 cases (30.4%), 6/56 in the affected vertebra (10.7%), and 24/330 in the screw trajectory (7.3%). At 2 years postoperatively, 11 new VFs had occurred in nine patients (16.1%), including VFs in nine adjacent segments that all occurred within 1 year after surgery. No cement migration or implant failure was noted. CONCLUSION: The novel surgical strategy for treating OVFs with cord compression consists of the most tailored and least invasive treatment for each patient. The positive mid- and long-term clinical and radiological outcomes observed could represent a step forward in devising the proposed algorithm.

[Establish mouse osteoblast -osteoclast cell co-culture system in a Transwell chamber].

OBJECTIVE: To establish osteoblast-osteoclast cell co-culture system in a Transwell chamber, and detect cell viability of osteoblasts and osteoclasts in system. METHODS: Osteoblast MC3T3-E1 and mouse monocytes RAW264.7 were cultivated in vitro. RANKL-induced mouse RAW264.7 monocytes differentiated into mature osteoclasts, osteoblast-osteoclast cell co-culture system was established in Transwell chamber. Cell activity of osteoblasts and osteoclasts were detected by CCK-8 experimenting, Alizarin Red staining, TRAP staining. The expression of OPG, ALP, RANKL, TGF-b1 gene and RANKL protein in osteoblast MC3T3-E1 were detected by PCR, Western-Blot methods. Also, the expression of RANK, NF-κB in gene and protein level in osteoclast were measured through the same method respectively. RESULTS: The co-culture system of Mouse MC3T3-E1 cells and RAW264.7 cell were established in Transwell chamber. Co-culture system affected cell division activities of osteoblasts and osteoclasts. Differentiation of osteoblasts were increased, while differentiation of osteoclast division were slight decreased under microscope observation. OPG (0.65±0.08) and ALP (0.16±0.01) gene expression of co-culture system were less than single culture OPG(1.00±0.08) and ALP (1.01±0.16); TGF-b1(4.42±0.21) and RANKL(4.12±1.04) of osteoblasts in co-culture system were higher than TGF-b1(1.00±0.10) and RANKL(1.00±0.09) under single culture. However, gene expression of RANK(0.63±0.06) and NF-κB(0.64±0.08) in co-culture system were decreased than RANK(1.00±0.08) and NF-κB(1.00±0.09), in single culture, and had significant differences. Similarly, protein expression of OPG(0.43±0.05) and NF-κB(0.59±0.05) of co-culture system were less than OPG(0.84±0.06) and NF-κB(1.13±0.03) of single culture. While RANKL protein expression (0.54±0.03)of co-culture system was more than single culture RANKL(0.31±0.03), and had statistically differences, which was in agreement of the trend of gene expression change. CONCLUSIONS: Co-culture system of mouse MC3T3-E1 cells and RAW264.7 cell was viable in Transwell chamber, and the activity of osteoblasts is higher than osteoclasts in co-culture system.

Risk factor analysis for re-collapse of cemented vertebrae after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP).

PURPOSE: Re-collapse of cemented vertebrae occasionally occurs after percutaneous augmentation. However, the potential risks still remain unclear. Several articles have reported some possible risk factors which were not consistent or comprehensive. This study aimed to make a retrospective review on patients with osteoporotic vertebral compression fracture (OVCF) after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) and to further analyse the risk factors for treated vertebral refracture. METHODS: All patients receiving the PKP/PVP with bilateral approach were retrospectively reviewed from January 2014 to January 2016, among whom 230 patients with single level augmentation (30 in refracture group and 200 in the non-refracture group) were enrolled according to inclusion criteria. The following covariates were reviewed: gender, age, height, weight, body mass index (BMI), bone mineral density (BMD), serum bone turnover markers, surgical parameters including approach, cement volume, anterior height, and Cobb angle restoration. Binary logistic regression analysis was used to determine the relative risk of re-collapse of cemented vertebrae. RESULTS: Regarding the patient data, weight, BMI, and BMD were of statistical significance in refracture group (P < 0.01), among which only low BMD was a risk factor to cemented vertebral re-collapse (P = 0.022, OR = 4.197). In respect of surgical variables, the better restoration of anterior height and Cobb angle was found in refracture group (P < 0.05), both of which might increase the refracture risk but not be risk factors (P = 0.065, OR = 0.891, and P = 0.937, OR = 0.996, respectively). Besides, less injected cement (3.30 ± 0.84 ml vs 4.46 ± 1.10 ml, P = 0.000, OR = 19.433) and PKP (P = 0.007, OR = 13.332) significantly boosted the potential risk of refracture (P < 0.001). CONCLUSION: Patients with low BMD, or undergoing PKP, or receiving a low volume of injected cement might have a high risk of re-collapse in surgical vertebrae.

[Analysis of clinical characteristics of 20 patients with pyogenic spondylitis].

OBJECTIVE: To investigate the diagnostic value of clinical manifestation, laboratory examination and imaging changes for pyogenic spondylitis and to summarize the clinical characteristics of patients with pyogenic spondylitis. METHODS: The clinical data, of 20 patients with pyogenic spondylitis were diagnosed by histopathological examination from March 2012 to March 2015, were retrospectively analyzed. There were 9 males and 11 females, aged from 43 to 72 years old with an average of 58.9 years. Included 3 cases of cervical vertebrae, 7 cases of thoracic vertebrae, 10 cases of lumbar vertebrae. Patients of blood analysis, erythrocyte sedimentation rate(ESR), C reactive protein(CRP), X rays, CT and MRI were performed before treatment. Visual analogue scale (VAS) was used to evaluate the pain of patients suffering from vertebral pain. RESULTS: All the patients had suffered from vertebral pain before treatment. VAS was 9 points in 4 cases, 8 points in 6 cases, 7 points in 1 case, 3 points in 6 cases, and 2 points in 3 cases. Among them, 7 patients complicated with neurological symptoms, 11 with aggravating night pain, 10 with fever. WBC and Neutrophil count (NEU) of 5 cases were increased and other 15 cases were normal;CRP of 19 cases were increased and 1 case was normal;ESR of all 20 cases were increased. X rays showed the intervertebral space narrowing in all 20 cases, 13 cases complicated with destruction of vertebral body; CT showed the lesions of vertebral body in the 20 cases and complicated with destruction, sclerosis of sclerotin; MRI showed that the lesions of the vertebral body in the T1 image had uneven medium low signal, in the T2 image of the 16 cases had uneven high signal and 2 cases had uniform and high signal, 2 cases had main high signal compliated with mixed signal. Thirteen patients underwent surgical treatment and 7 patients received conservative treatment, and the patients left hospital while VAS had significantly improved after treatment. CONCLUSIONS: Pyogenic spondylitis is easy to be misdiagnosed or missed in clinic. It can be combined with the clinical manifestations, laboratory examination and imaging characteristics in order to make a definite diagnosis for purulent spondylitis in early.