Using a developed co-culture device to evaluate the proliferation of bone marrow stem cells by stimulation with platelet-rich plasma and electromagnetic field.

BACKGROUNDS: Bone marrow stem cell can differentiate to osteoblast by growth factors, pulsed low-intensity ultrasound and electric magnetic field. In the research, bone marrow stem cells were cultured; bone marrow stem cells in culture can be stimulated by platelet-rich plasma and electric field. METHODS: The culture well of the co-cultivation device has a radius of 7.5 mm and a depth of 7 mm. It is divided into two sub-chambers separated by a 3 mm high and 1 mm wide barrier. The bone marrow stem cells were seeded at a density of 2 × 104 cells and the medium volume was 120µl. Platelet-rich plasma (PRP) or platelet-poor plasma (PPP) was added to the other sub-chamber at a volume of 10µl. The bone marrow stem cells were subjected to different electric fields (0 ~ 1 V/cm) at a frequency of 70 kHz for 60 min. RESULTS: The highest osteogenic capacity of bone marrow stem cells was achieved by addition of PRP to electric field stimulation (0.25 V/cm) resulted in a proliferation rate of 599.78%. In electric field stimulation (0.75 V/cm) with PPP, the proliferation rate was only 10.46%. CONCLUSIONS: Bone marrow stem cell with PRP in the co-culture device combined with electric field at 0.25 V/cm strength significantly promoted the growth of bone marrow stem cells.

Self-assisted wound healing using piezoelectric and triboelectric nanogenerators.

The complex process of wound healing depends on the coordinated interaction between various immunological and biological systems, which can be aided by technology. This present review provides a broad overview of the medical applications of piezoelectric and triboelectric nanogenerators, focusing on their role in the development of wound healing technology. Based on the finding that the damaged epithelial layer of the wound generates an endogenous bioelectric field to regulate the wound healing process, development of technological device for providing an exogenous electric field has therefore been paid attention. Authors of this review focus on the design and application of piezoelectric and triboelectric materials to manufacture self-powered nanogenerators, and conclude with an outlook on the current challenges and future potential in meeting medical needs and commercialization.

Instrumented Posterolateral fusion versus instrumented Interbody fusion for degenerative lumbar diseases in uremic patients under hemodialysis.

BACKGROUND: Advances in hemodialysis have facilitated longer lifespan and better quality of life for patients with end stage renal disease (ESRD). Symptomatic degenerative lumbar diseases (DLD) becomes more common in patients with ESRD. Posterior instrumented fusion remains popular for spinal stenosis combining instability. Only a few sporadic studies mentioned about surgical outcomes in patients with ESRD underwent spine surgeries, but no one discussed about which fusion method was optimal for this kind of patients. In this study, we compared the differences between lumbar posterolateral fusion (PLF) and lumbar interbody fusion (IBF) in uremic patients underwent instrumented lumbar surgeries. METHODS: Between January 2005 and December 2017, ESRD patients under maintenance hemodialysis underwent posterior instrumented fusion for DLD were reviewed. A PLF group and an IBF group were identified. The demographic data was collected using their medical records. Clinical outcomes were evaluated by Oswestry Disability Index (ODI) and the visual analogue scale (VAS); radiographic results were assessed using final fusion rates. Any surgical or implant-related complication was documented. RESULTS: A total of 34 patients (22 women and 12 men, mean age of 65.4 years) in PLF group and 45 patients (26 women and 19 men, mean age of 65.1 years) in IBF group were enrolled. Both groups had similar surgical levels. The operation time was longer (200.9 vs 178.3 min, p = 0.029) and the amount of blood loss was higher (780.0 vs 428.4 ml, p = 0.001) in the IBF group. The radiographic fusion rate was better in the PLF group but without significant difference (65.2% vs 58.8%, p = 0.356). Seven in the PLF group and ten in the IBF group developed surgical complications (20.5% vs. 22.2%, p = 0.788); three patients in the PLF group (8.8%) and five patients in the IBF group (11.1%) received revision surgeries because of implant-related or wound complications. Comparing to preoperative ODI and VAS, postoperative ODI and VAS obtained significant improvement in both groups. CONCLUSIONS: Successful fusion rates and clinical improvement (VAS, ODI) were similar in IBF and PLF group. Uremic patients underwent IBF for DLD had longer length of operation and higher operative blood loss than underwent PLF.

The fate of thoracolumbar surgeries in patients with Parkinson's disease, and analysis of risk factors for revision surgeries.

BACKGROUND: Compared to patients without Parkinson's disease (PD), patients with PD who underwent spinal surgeries were reported to have a relatively high complication rate. However, studies that analyze surgical risk factors for these patients are limited. METHODS: From October 2004 to April 2015, patients with PD who underwent spinal surgeries at our department were reviewed. Patients who underwent lumbar or thoracolumbar instrumented surgeries due to degeneration or deformity disease were included. Any reason for revision surgery was recorded. Risk factors including patients' factors, surgical factors, and lumbo-pelvic radiographic parameters were analyzed. Patients' factors included patients' underlying diseases, body mass index (BMI), osteoporotic status, and PD's severity using the modified Hoehn and Yahr staging scale. Surgical factors included surgical levels, extending to thoracic spine or not, corrective osteotomy, with anterior approach or not, and interbody device. Radiographic parameters included lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), coronal Cobb's angles, and score for spino-pelvic realignment achievement. RESULTS: A total of 66 patients were enrolled. The mean age at surgery was 69.0 years old. The mean follow-up time was 51.2 months. Twenty-six revision surgeries were required in 19 patients (29%). Risk factors for revision surgery included modified Hoehn and Yahr stage ≥3 (p <  0.001), cancer history (p = 0.024), osteoporosis (P = 0.012) and underwent corrective osteotomy (p = 0.035). According to binary logistic regression analysis, the modified Hoehn and Yahr stage ≥3 (p <  0.001) was the only independent risk factor. The Kaplan-Meier analysis revealed patients with long instrumentation (surgical levels > 3), T-spine instrumentation, and lower score of spino-pelvic realignment achievement tended to have earlier revision. CONCLUSION: For PD patients planning for elective thoracolumbar surgery, aggressive control status of PD before or after surgery is necessary to prevent surgical complications. Longer surgical levels and corrective osteotomy also tended to have earlier revision. A better score in spino-pelvic realignment achievement after surgery could reduce occurrence of revision.

Surgical outcomes of infectious spondylitis after vertebroplasty, and comparisons between pyogenic and tuberculosis.

BACKGROUND: Infection after vertebroplasty (VP) is a rare but serious complication. Previous literatures showed most pathogens for infection after VP were bacteria; tuberculosis (TB) induced infection after VP was extremely rare. We reported our treatment experiences of cases with infectious spondylitis after VP, and compared the differences between developed pyogenic and TB spondylitis. METHODS: From January 2001 to December 2015, 5749 patients had undergone VP at our department were reviewed retrospectively. The causative organisms were obtained from tissue culture of revision surgery. Parameters including type of surgery, the interval between VP and revision surgery, neurologic status, and visual analog scale (VAS) of back pain were recorded. Laboratory data at the time of VP and revision surgery were collected. Charlson comorbidity index (CCI), preoperative bacteremia, urinary tract infection (UTI), pulmonary TB history were also analyzed. RESULTS: Eighteen patients were confirmed with developed infectious spondylitis after VP (0.32%, 18/5749). Two were male and 16 were female. The median age at VP was 73.4 years. Nine patients were TB and the other nine patients were pyogenic. The interval between VP and revision surgery ranged from 7 to 1140 days (mean 123.2 days). The most common type of revision surgery was anterior combined with posterior surgery. Seven patients developed neurologic deficit before revision surgery. Three patients died within 6 months after revision surgery, with a mortality of 16.7%. Finally, VAS of back pain was improved from 7.4 to 3.1. Seven patients could walk normally, the other 8 patients had some degree of disability. Both pyogenic and TB group had similar age, sex, and CCI distribution. The interval between VP and revision surgery was shorter in the patients with pyogenic organisms (75.9 vs 170.6 days). At revision surgery, WBC and CRP were prominently elevated in the pyogenic group. Five in the pyogenic group had UTI and bacteremia; five in TB group had a history of lung TB. CONCLUSIONS: Infection spondylitis after VP required major surgery for salvage with a relevant part of residual disability. Before VP, any bacteremia/UTI or history of pulmonary TB should be reviewed rigorously; any elevation of infection parameters should be scrutinized strictly.

Treatment of thoracolumbar burst fractures by short-segment pedicle screw fixation using a combination of two additional pedicle screws and vertebroplasty at the level of the fracture: a finite element analysis.

BACKGROUND: Traditional one-above and one-below four-screw posterior short-segment instrumentation is used for unstable thoracolumbar burst fractures. However, this method has a high rate of implant failure and early loss of reduction. The purpose of this study was to use finite element (FE) analysis to determine the effect of treating thoracolumbar burst fractures by short-segment pedicle screw fixation using a combination of two additional pedicle screws and vertebroplasty at the level of the fracture. METHODS: An intact T11-L1 spine FE model was created from the computed tomography images of a male subject. Four fixation models with posterior fusion devices (pedicle screws, rods, cross-link) were established to simulate an unstable thoracolumbar fracture with different fusion surgeries: short-segment fixation with: 1) a link (S-L); 2) intermediate bilateral screws (S-I); 3) a link and calcium sulfate cement (S-L-C); 4) intermediate bilateral screws and calcium sulfate cement (S-I-C). Different loading conditions (flexion, extension, lateral bending, and axial rotation) were applied on the models and analyzed with a FE package. The range of motion (ROM), and the maximum value and distribution of the implant stress, and the stress in the facet joint, were compared between the intact and fixation models. RESULTS: The ROM in flexion, extension, axial rotation, and lateral bending was the smallest in the S-I-C model, followed by the S-I, S-L-C, and S-L models. Maximum von Mises stress values were larger under lateral bending and axial rotation loadings than under flexion and extension loading. High stress was concentrated at the crosslink and rod junctions. Maximal von Mises stress on the superior vertebral body for all loading conditions was larger than that on the inferior vertebral body. The maximal von Mises stress of the pedicle screws during all states of motion were 265.3 MPa in S-L fixation, 192.9 MPa in S-I fixation, 258.4 MPa in S-L-C fixation, and 162.3 MPa in S-I-C fixation. CONCLUSIONS: Short-segment fixation with two intermediate pedicle screws together with calcium sulfate cement at the fractured vertebrae may provide a stiffer construct and less von Mises stress of the pedicle screws and rods as compared to other types of short-segment fixation.

Surgical outcomes after instrumented lumbar surgery in patients of eighty years of age and older.

BACKGROUND: In Taiwan, the life expectancy of an 80-year-old man is 88.4 years and the life expectancy of an 80-year-old woman is 89.8 years. Some of these people will develop symptomatic degenerative lumbar diseases that interfere with an active lifestyle. These older surgical candidates usually ask the surgeon whether it would be safe to undergo surgery. However, there is no literature assessing the outcomes of laminectomy, fusion and posterior fixation for degenerative lumbar diseases in patients older than 80 years. The purpose of this study was to report the surgical outcomes of patients 80 years of age and older who underwent spinal decompression and instrumented lumbar arthrodesis for degeneration lumbar diseases. METHODS: We retrospectively reviewed patients with degenerative lumbar diseases and spinal stenosis who underwent surgery between January 2010 and December 2012. Inclusion criteria were age greater than or equal to 80 years, decompression with instrumented lumbar arthrodesis, and at least 2 years of follow-up. Totally 89 patients were studies. Clinical outcomes were evaluated according to the Oswestry Disability Index (ODI) and visual analogue scale (VAS) of leg and back pain. Plain radiographs (lateral, anteroposterior, and flexion-extension) were used to assess the status of fusion and implant-related complications. Every complication during admission and any implant-related or failed-back syndrome requiring a second surgery was documented. T test and Fisher's exact test were used for statistical analysis. RESULTS: Five patients were lost to follow-up, and another 12 died during the follow-up period. One patient died due to cerebral stroke just 2 days after surgery, and the other 11 patients passed away 3 months to 4 years postoperatively. In all, 72 patients had an adequate follow-up: 44 were female and 28 were male. The average age at surgery was 82.5 ± 2.6 years (80 to 93); 63 patients underwent their first lumbar surgery, and nine patients received a second surgery. Patients underwent arthrodesis surgeries were from a single-level to a 7-level. Four patients developed complications (5.6 %, 4/72). At the final follow-up, the average ODI score was lower than the preoperative score (30.0 vs. 61.8) (p < 0.001). The average VAS score also showed improvement (leg: p < 0.001; back: p < 0.001). Forty-three patients were classified as "satisfied", and 29 were "dissatisfied". Longer operation time (p = 0.014) and development of complications (p = 0.049) were related to poor clinical results. Radiographic follow-up showed that 53 patients had solid union, ten had a probable union, and nine had pseudarthrosis. More surgical segments led to a greater chance of pseudarthrosis (2.0 ± 0.9 vs 3.0 ± 1.8, p = 0.003). CONCLUSION: Longer instrumented segments and development of complications contributed to worse clinical and radiographic outcomes. With proper patient selection, posterior decompression with instrumented fusion can be safe and effective for patients 80 years of age and older with degenerative lumbar conditions.

Bone Marrow Mesenchymal Stem Cells Expressing Baculovirus-Engineered Bone Morphogenetic Protein-7 Enhance Rabbit Posterolateral Fusion.

Previous studies have suggested that bone marrow-derived mesenchymal stem cells (BMDMSCs) genetically modified with baculoviral bone morphogenetic protein-2 (Bac-BMP-2) vectors could achieve successful fusion in a femur defect model or in a spinal fusion model. In this study, BMDMSCs expressing BMP-7 (Bac-BMP-7-BMDMSCs) were generated. We hypothesized that Bac-BMP-7-BMDMSCs could secrete more BMP-7 than untransduced BMDMSCs in vitro and achieve spinal posterolateral fusion in a rabbit model. Eighteen rabbits underwent posterolateral fusion at L4-5. Group I (n = 6) was implanted with collagen-ß-tricalcium phosphate (TCP)-hydroxyapatite (HA), Group II (n = 6) was implanted with collagen-ß-TCP-HA plus BMDMSCs, and Group III (n = 6) was implanted with collagen-ß-TCP-HA plus Bac-BMP-7-BMDMSCs. In vitro production of BMP-7 was quantified with an enzyme-linked immunosorbent assay (ELISA). Spinal fusion was examined using computed tomography (CT), manual palpation, and histological analysis. ELISA demonstrated that Bac-BMP-7-BMDMSCs produced four-fold to five-fold more BMP-7 than did BMDMSCs. In the CT results, 6 fused segments were observed in Group I (50%, 6/12), 8 in Group II (67%, 8/12), and 12 in Group III (100%, 12/12). The fusion rate, determined by manual palpation, was 0% (0/6) in Group I, 0% (0/6) in Group II, and 83% (5/6) in Group III. Histology showed that Group III had more new bone and matured marrow formation. In conclusion, BMDMSCs genetically transduced with the Bac-BMP-7 vector could express more BMP-7 than untransduced BMDMSCs. These Bac-BMP-7-BMDMSCs on collagen-ß-TCP-HA scaffolds were able to induce successful spinal fusion in rabbits.

Cell Therapy Using Bone Marrow-Derived Stem Cell Overexpressing BMP-7 for Degenerative Discs in a Rat Tail Disc Model.

Degenerative discs can cause low back pain. Cell-based transplantation or growth factors therapy have been suggested as a strategy to stimulate disc regeneration. Bone marrow-derived mesenchymal stem cells (BMDMSC) containing bone morphogenetic protein-7 (BMP-7) gene were constructed. We evaluated the effectiveness of these BMP-7 overexpressing cells on degenerative discs in rat tails. In vitro and in vivo studies were designed. In the first stage, the rats were divided into two group according to discs punctured by different needle gauges (18 gauge and 22 gauge). In the second stage, the ideal size of needle was used to induce rat tail disc degeneration. These animals are divided into three groups according to timing of treatment (zero-week, two-week, four-week). Each group was divided into three treating subgroups: control group, BMDMSC group, and Baculo-BMP-7-BMDMSC group. Each rat undergoes radiography examination every two weeks. After eight weeks, the discs were histologically examined with hematoxylin and eosin stain and Alcian blue stain. The 18-gauge group exhibited significant decrease in disc height index (%) than 22-gauge group at eight weeks at both Co6-7 (58.1% ± 2.8% vs. 63.7% ± 1.0%, p = 0.020) and Co8-9 discs (62.7% ± 2.8% vs. 62.8% ± 1.5%, p = 0.010). Baculo-BMP-7-BMDMSCs group showed significant difference in disc height index compared to the BMDMSCs group at both Co6-7 (93.7% ± 1.5% vs. 84.8% ± 1.0%, p = 0.011) and Co8-9 (86.0% ± 2.1% vs. 81.8% ± 1.7%, p = 0.012). In Baculo-BMP-7-BMDMSCs group, the zero-week treatment subgroup showed significant better in disc height index compared to two-week treatment group (p = 0.044), and four-week treatment group (p = 0.011). The zero-week treatment subgroup in Baculo-BMP-7-BMDMSCs group also had significant lower histology score than two-week treatment (4.3 vs. 5.7, p = 0.045) and four-week treatment (4.3 vs. 6.0, p = 0.031). In conclusion, Baculo-BMP-7-BMDMSC can slow down the progression of disc degeneration, but could not provide evidence of regeneration. Early treatment might obtain more distinct results.

Effects of low-intensity pulsed ultrasound on spinal pseudarthrosis created by nicotine administration: a model of lumbar posterolateral pseudarthrosis in rabbits.

OBJECTIVES: Low-intensity pulsed ultrasound (US) can enhance spinal fusion and fracture healing; however, its effect on spinal pseudarthrosis has not been reported in the literature. We hypothesized that low-intensity pulsed US could overcome spinal pseudarthrosis created by nicotine administration. METHODS: Thirty-two rabbits underwent posterolateral fusion with an iliac bone graft and nicotine administration. At 5 weeks, the spines were examined by computed tomography (CT) to determine the presence of pseudarthrosis. All rabbits with pseudarthrosis were randomly divided into groups A, B, C, and D according to treatment: no second graft, iliac autograft only, low-intensity pulsed US only, and iliac autograft and low-intensity pulsed US, respectively. At 10 weeks, the rabbits were euthanized, and the specimens were assessed with radiography, CT, manual palpation, and histologic analysis. RESULTS: One rabbit was lost because of severe infection. Twenty-seven (87%) had pseudarthrosis on CT at 5 weeks. On manual palpation at 10 weeks, the fusion rates were 0%, 29%, 0%, and 57% in groups A, B, C, and D, respectively. Group D had highest radiographic scores (mean ± SD, 2.87 ± 0.92), and the difference was statistically significant compared to the other groups (P < .001). Computed tomography confirmed that group D had the most fused segments at 10 weeks. Histologic specimens from group D also showed the most mature bone formation inside the fusion mass. CONCLUSIONS: Low-intensity pulsed US can enhance spinal fusion but cannot overcome spinal pseudarthrosis created by nicotine administration. Stopping nicotine consumption or administering a more powerful bone substitute might be an alternative method for overcoming spinal pseudarthrosis.

The effects of anterior vacuum disc on surgical outcomes of degenerative versus spondylolytic spondylolisthesis: at a minimum two-year follow-up.

BACKGROUND: The vacuum phenomenon within the intervertebral disc usually represents disc degeneration. There are no reports in the English literature that focus on the effect of an anterior vacuum disc on surgical outcome of same-segment spondylolisthesis. METHODS: Patients with degenerative spondylolisthesis (DS) or isthmic spondylolisthesis (IS) who underwent a spinal surgery between January 2005 and December 2006 were reviewed. Patients who met certain criteria, including (1) only mono-segment spondylolisthesis, (2) gas air within the disc space of the spondylolisthesis segment on preoperative radiographs, (3) having received posterior decompression, posterior pedicle screw fixation, and posterolateral fusion, and (4) at least 12 months of follow-up radiographs available to define the posterolateral fusion rate, were enrolled into the study. Four radiographic parameters (disc height, translation, intradiscal angle, segmental angle) were assessed. Two-year postoperative radiographs were used to determine whether the posterolateral segment was fused or not. Clinical outcome and complications during the follow-up period were documented. RESULTS: Incidence of the disc vacuum phenomenon was significantly higher in the IS group than in the DS group (p < 0.001). The IS group had more listhesis and a narrower disc height on preoperative static radiographs; however, the DS group had a more prominent angle and listhesis change in preoperative dynamic variables. The posterolateral fusion rate was significantly higher in the IS group (p = 0.019). The preoperative Oswestry Disability Index (ODI) score, the final ODI, and the ODI difference were similar between groups. More excellent and good results were seen in the IS group. Besides, better final ODI and results were seen in the bilateral fusion group than in the nonfusion group. CONCLUSION: The disc vacuum phenomenon is not equal to anterior instability absolutely. Determination of stability or instability in a vacuum disc should be considered by a combination of dynamic radiographs. In the present study, vacuum discs in the DS group showed more instability and a higher posterolateral pseudoarthrosis rate.

Surgical outcomes of degenerative lumbar spondylolisthesis with anterior vacuum disc: can the intervertebral cage overcome intradiscal vacuum phenomenon and enhance posterolateral fusion?

BACKGROUND: The vacuum phenomenon within an intervertebral disc is not an uncommon radiographic finding in the elderly. However, no reports in the English literature have focused on the effect of an anterior vacuum disc in relation to surgical outcome of same-segment spondylolisthesis. We hypothesized that instrumented posterolateral fusion is not adequate in this situation and that additional interbody fusion with cages would provide better radiographic and clinical outcomes. METHODS: The medical records of 72 patients who underwent instrumented fusion for one-segment degenerative lumbar spondylolisthesis with a vacuum disc were reviewed. Thirty-three patients were placed in the noncage group and 39 in the cage group based on whether or not augmentation with an intervertebral cage was carried out. Radiographic parameters (disc height, translation, intradiscal angle, segmental angle, and fusion) on preoperative, postoperative, and final radiographs were compared between groups. The Oswestry Disability Index (ODI) and Brosky criteria were used to evaluate clinical outcomes. RESULTS: Blood loss and operation time were greater in the cage group but without a significant difference (p = 0.271, p = 0.108, respectively). Preoperative radiographic data were similar between groups, but the cage group had more intradiscal lordosis, less translation, a higher disc height after surgery, and maintained these advantages at the final follow-up. In addition, the posterolateral fusion rate was significantly higher in the cage group (92.3% vs. 56.1%, p < 0.001), and they obtained more ODI improvement (30.62 vs. 26.39, p = 0.369) and a higher final satisfaction rate (79.5% vs. 57.6%, p = 0.044). There was no decrease in the incidence of developed adjacent segmental disease in the noncage group. CONCLUSIONS: The vacuum sign at the spondylolisthesis segment should be regarded as another sign of instability. We suggest that instrumented posterolateral fusion simultaneous with intervertebral fusion with a cage can overcome this situation.

Surgery for metastatic epidural spinal cord compression in thoracic spine, anterior or posterior approach?

BACKGROUND: The most commonly encountered tumour of the spine is metastasis, and thoracic spine is the most commonly metastatic spine. Controversy exists regarding the optimal surgical approach for this kind of patient. The author conducted a study to assess the differences between anterior thoracotomy and a posterior approach in patients with malignant epidural cord compression in the thoracic spine. METHODS: Between January 2004 and December 2017, 97 patients with metastatic thoracic lesion were stratified into two groups by approach method to the lesion site: Group A - mean anterior thoracotomy, decompression and fixation; and Group P - represented posterior decompression and fixation. Survival time, neurologic status, each complication by surgery or in hospital, and days in intensive care unit(ICU) were compared. RESULTS: Twenty-five patients were grouped in Group A, and 72 patients belonged to Group P. Lung cancer was the most common primary cancer in both groups. Operation time (213.0 vs. 199.2 min, p = 0.380) and blood loss (912.5 vs. 834.4 ml, p = 0.571) were not statistically significantly different between the two groups. Six patients in Group A (24%) and 6 in Group P (8.3%) developed complications (p = 0.040). Patients in Group A required more days of care in ICUs (2.36 vs. 0.19 days, p < 0.001). The longer survival was seen in Group P (15.4 vs. 11.2 months) but with no significant difference. CONCLUSION: A lower surgical complication rate and fewer days of care in ICU were seen in Group P. The authors would prefer a posterior approach for those with thoracic metastatic tumour.

The Influences of Spinopelvic Parameters and Associated Factors on Development of Proximal Instrumented Fracture After Posterior Instrumentation.

OBJECTIVE: To investigate influences of spinopelvic parameters, such as lumbar lordosis (LL) angles, pelvic incidence, sacral slope, pelvic tilt, and sagittal vertical axis, on development of the proximal junctional failure fracture type after posterior instrumentation. METHODS: This retrospective 1:3 matched case-control cohort study included 24 patients who developed proximal instrumented fracture in the study group and 72 patients without proximal junctional failure in the control group. Weighted Charlson Comorbidity Index and bone mineral density with T-score were recorded. In addition to spinopelvic parameters, proximal local kyphosis (PLK), which refers to a kyphosis angle between the upper end plate of upper instrumented vertebra plus 1 level and the lower end plate of upper instrumented vertebra; pelvic incidence-LL mismatch; and spinopelvic realignment score were calculated. RESULTS: More comorbidities (Charlson Comorbidity Index, P = 0.002) and poorer bone density (T-score, P = 0.001) were noted in the study group. Before surgery, the study group had significantly lower LL (P = 0.046) and sacral slope (P = 0.043) and significantly higher PLK (P < 0.001) and pelvic tilt (P = 0.044) than the control group. Postoperatively, the study group had significantly higher PLK (P < 0.001) and lower LL (P = 0.031) than the control group; the degree of pelvic incidence-LL mismatch (P = 0.007) remained significantly higher in the study group. Preoperative (P = 0.026) and postoperative (P = 0.045) spinopelvic realignment scores was worse in the study group. Multivariate analysis revealed that postoperative PLK was the most significant radiographic factor to predict proximal instrumented fracture (P = 0.002, odds ratio 1.140, 95% confidence interval). CONCLUSIONS: In our experience, appropriate LL and lower PLK should be obtained at surgery to prevent development of instrumented fracture.

Proximal junctional fractures after long-segment instrumented fusion: comparisons between upper instrumented vertebrae and upper instrumented vertebrae + 1.

INTRODUCTION: Proximal junctional failure (PJF) is a well-known complication after long-segment (at least 4 vertebral levels) instrumented fusion. The etiologies of PJF include degenerative processes or are fracture induced. The fracture type of PJF includes vertebral fractures developed at the upper instrumented vertebrae (UIV) or UIV + 1. The purpose of this study was to investigate clinical and radiographic features of these two subtypes of PJF and to analyze risk factors in these patients. METHOD: In total, forty-two patients with PJF who underwent revision surgery were included. Twenty patients suffered fractures at the UIV, and the other 22 cases had fractures at UIV + 1. The weighted Charlson Comorbidity Index (CCI) and bone mineral density (BMD) T scores for these patients were recorded. Surgery-related data of index surgery and complications were collected. Radiographic parameters including pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), lumbar lordosis (LL), and PI-LL were recorded in both groups before and after the revision surgery. RESULT: Both groups had severe osteoporosis and comorbidities. The interval between the index surgery and revision surgery was shorter in the UIV group than in the UIV + 1 group (8.2 months vs. 35.9 months; p < 0.001). The analysis for radiographic parameters in UIV and UIV + 1 group demonstrated no significant change before and after the revision surgery. However, the preoperative radiographic analysis showed a larger PT (31.5° vs. 23.2°, p = 0.013), PI (53.7° vs. 45.3°, p = 0.035), and SVA (78.6° vs. 59.4°, p = 0.024) in the UIV group compared to the UIV + 1 group. The postoperative radiographic analysis showed a larger PI-LL (27.8° vs. 18.1°, p = 0.016) in the UIV group compared to the UIV + 1 group. CONCLUSION: PJF in the UIV group tends to occur earlier than in the UIV + 1 group. Moreover, more severe global sagittal imbalances were found in the UIV group than in UIV + 1 group.

Cement augmentation for treatment of high to mid-thoracic osteoporotic compression fractures, high-viscosity cement percutaneous vertebroplasty versus balloon kyphoplasty.

Whilst the majority of the literature suggests that balloon kyphoplasty (BKP) can relieve pain associated with vertebral compression fractures (VCFs), evidence of high-viscosity cement (HVC) vertebroplasty (VP) or low viscosity cement (LVC) BKP for the treatment of VCFs at the levels of high and mid-thoracic vertebrae remains limited. The purpose of this study was to identify the different outcomes between HVC VP and LVC BKP used to repair high (T4-6) and mid (T7-9)-thoracic VCFs. A total of 114 patients with painful collapsed single-level vertebrae at high to mid-thoracic level who had undergone HVC VP or LVC BKP at a single tertiary medical center was reviewed retrospectively. All patients were divided into the HVC VP group (n = 72) and the LVC BKP group (n = 42). Clinical outcomes including demographic data and visual analogue scale (VAS) were compared. Radiographic data were collected preoperatively, postoperatively, and at final follow-up. More volume (ml) of cement injection was seen in the LVC BKP group (4.40 vs. 3.66, p < 0.001). The operation time (minutes) of the HVC VP group was significantly less than that of the LVC BKP group (33.34 vs. 39.05, p = 0.011). Leakage rate of cement was also fewer in the HVC VP group (26/72 vs. 27/42, p = 0.004). Compared with preoperative data, the VAS was improved after surgery in both groups. The LVC BKP group corrected more middle vertebral body height and local kyphosis angle than the HVC VP group. The outcomes of LVC BKP were not superior to that of HVC VP. HVC VP might be a good alternative to LVC BKP in the treatment of osteoporotic VCFs in high to mid-thoracic spine.

High viscosity bone cement vertebroplasty versus low viscosity bone cement vertebroplasty in the treatment of mid-high thoracic vertebral compression fractures.

BACKGROUND CONTEXT: As science and technology have advanced, novel bone cements with numerous formulated ingredients have greatly evolved and been commercialized for vertebroplasty. Recently, viscosity has been a focus to achieve better clinical outcomes and fewer complications. Meanwhile, the experience in the treatment of mid (T7-9) to high (T4-6) thoracic vertebral compression fractures is limited. PURPOSE: The objective of this study was to identify the different outcomes between high-viscosity bone cement (HVBC) and low-viscosity bone cement (LVBC) used to repair mid (T7-9)- and high (T4-6)- thoracic vertebral compression fractures. STUDY DESIGN/SETTING: This study was a single-center, retrospective cohort study PATIENT SAMPLE: A consecutive series of 107 patients with a total of 144 vertebrae was included. OUTCOME MEASURES: The anterior vertebral height (AVH), middle vertebral height (MVH), posterior vertebral height (PVH), local kyphotic angle (KA), Cobb angle (CA), and other associated parameters were evaluated radiologically at several time points-preoperative, surgery day 0, postoperative day 1, and 6-month follow-up. Pain evaluation was assessed by using a visual analog scale (VAS) before and 6 months after the procedure. METHODS: The patients were divided into two groups according to the viscosity of the bone cement used, and plain film and magnetic resonance imaging (MRI) of the vertebrae were used to calculate parameters. The patient characteristics; bone cement brand; changes in AVH, MVH, PVH, KA, CA, and VAS; and complications of each patient were recorded and then analyzed. RESULTS: Both groups showed increased vertebral body height, corrected KA, and CA after vertebroplasty. There were no significant differences between the HVBC and LVBC groups (ΔAVH: 2.19±2.60 vs. 2.48±3.09, p=.555; ΔMVH: 1.25±3.15 vs. 1.89±2.58, p=.192; ΔKA: -5.46±4.58 vs -5.37±4.47, p=.908; and ΔCA: -4.22±4.23 vs. -4.56±5.17, p=.679). There were significant preoperative to postoperative and preoperative to follow-up changes in AVH (HVBC, p=.012 and .046, respectively; LVBC, p=.001 and .015, respectively); a significant preoperative to postoperative change in MVH (HVBC, p=.045; LVBC, p=.001); and significant preoperative to postoperative and preoperative to follow-up changes in KA and CA (KA: HVBC, p=0.000 and .003, respectively; LVBC, p=.000 and .000, respectively; CA: HVBC, p=.017 and .047, respectively; LVBC, p=.006 and .034, respectively). The volume of cement injected was significantly higher with HVBC (3.66±1.36 vs. 3.11±1.53, p=.024), and the use of HVBC was associated fewer cases with cement leakage (26 vs. 45, p=.002). Furthermore, there was no difference between the groups in the incidence of adjacent fracture. Both groups showed an improved VAS score at follow-up, with statistically greater improvement in the HVBC group (2.40±1.53 vs. 3.07±1.69, p=.014). Moreover, significantly fewer patients with a VAS score ≥ 3 were found in the HVBC group (22 vs. 39, p=.004) CONCLUSIONS: HVBC and LVBC are safe and effective to treat mid-to-high level thoracic vertebral compression fractures. Compared with LVBC, HVBC shows less cement leakage, a greater injection volume, and better postoperative pain relief.

Percutaneous Endoscopic Interbody Debridement and Fusion (PEIDF) Decreases Risk of Sepsis and Mortality in Treating Infectious Spondylodiscitis for Patients with Poor Physical Status, a Retrospective Cohort Study.

Background: Postoperative immunosuppression is associated with blood loss and surgical trauma during surgery and subsequently predisposes patients to increased morbidity. Spine endoscopic surgery has been accepted as an effective surgical technique with less surgical trauma and less blood loss for the complication of infectious spondylodiscitis. Therefore, the aim of this study was to investigate whether PEIDF could reduce the morbidity rates for patients with infectious spondylodiscitis. Methods: We launched a retrospective cohort study on the comparison of the perioperative prognosis between PEIDF and conventional open surgery for single-level lumbar infectious spondylodiscitis in patients with poor physical health (ASA ≥ 4) from 2014 to 2019. Results: Forty-four patients were included in this study. Fifteen of them underwent PEIDF, and the rest of the 29 patients were treated with open surgery. Less surgical blood loss (p < 0.001) and intraoperative transfusions (p < 0.001) with a better decline of CRP (p = 0.017) were statistically significant in patients receiving PEIDF. Patients undergoing conventional open surgery encountered more postoperative sepsis (p = 0.030), a higher qSOFA score (p = 0.044), and prolonged-time for CRP normalization (p = 0.001). Conclusions: PEIDF minimizes a poor postoperative outcome due to less surgical trauma, intraoperative blood loss, and the need for a blood transfusion.

Low-intensity pulsed ultrasound enhances healing of laminectomy chip bone grafts on spinal fusion: a model of posterolateral intertransverse fusion in rabbits.

BACKGROUND: Laminectomy-derived chip bone graft was usually used in spinal fusion; however, the result of this kind of local bone used in lumbar posterolateral fusion is uncertain. This study tested the hypotheses that low-intensity pulsed ultrasound (LIPU) can accelerate the healing process of laminectomy bone chips in a spinal fusion and enhance the union rate. METHODS: Forty-eight rabbits were randomly divided into three groups for the spinal unilateral uninstrumented posterolateral fusion of L5-L6: autologous iliac bone graft (AIBG), laminectomy chip bone graft (LCBG), LCBG plus LIPU (LCBG + LIPU). Each group was subdivided into 6-week and 12-week subgroups. All rabbits were subjected to radiographic examination and manual testing. All successful spinal fusion specimens received biomechanical testing and a histologic examination. RESULTS: The LCBG + LIPU group had the highest successful fusion rate at 6-week and 12-week examination (75% and 100%, respectively). At 6 weeks, the average maximum toque at failure values of the fusion masses for the LCBG + LIPU group was significantly higher than that for the LCBG group (p = 0.034). The average maximum torque of the 12-week LCBG + LIPU group was significantly higher than those of the 12-week AIBG and 12-week LCBG groups (p = 0.040 and p = 0.026, respectively). CONCLUSIONS: This study suggested that LIPU can enhance bone healing. With augmentation by LIPU, laminectomy chip bone used in lumbar posterolateral fusion can achieve a similar fusion rate and stronger fusion mass than those of an AIBG.

Repeated percutaneous vertebroplasty for refracture of cemented vertebrae.

BACKGROUND: Percutaneous vertebroplasty is an efficient procedure to treat painful osteoporotic vertebral compression fractures. However, refracture of cemented vertebrae occurs rarely after percutaneous vertebroplasty. This study was undertaken to investigate the incidence, characteristics, predisposing factors, and mistakes in technique associated with refracture of the same vertebra after percutaneous vertebroplasty. METHODS: From 2001 to 2008, PVP with bone cement (polymethylmethacrylate, PMMA) was carried out in 2,291 patients with 2,581 PVP procedures. The etiologies including pathologic fracture (including metastasis, osteolytic tumor, hemangioma) in 299 patients, infectious spondylitis in 4 patients and osteoporotic compression fractures in 1,988 patients. A total of 1,988 patients with 2,110 VCFs underwent PVP with PMMA cement after failing conservative treatment for at least 3 months. New recollapsed vertebral fractures were diagnosed as recurrent intractable back pain, postoperatively correlated with serial plain radiography and MR image. Clinical parameters such as age, gender, body mass index, and fracture-free interval (from the date of the initial intervention with percutaneous vertebroplasty to the diagnosis of subsequent fractures) were recorded. Parameters related to imaging and technical characteristics, including the amount of bone cement injected per procedure, level, the presence of osteonecrosis in the vertebral body, and the surgical approach (uni- or bipedicles), the restoration of kyphosis angle and height of the anterior border of the collapsed vertebral body, and any leakage of cement into the disk space were also recorded. RESULTS: In a 2-year follow-up, 1,800 patients with 1,820 VCFs were retrospectively reviewed and 10 patients with 10 VCFs developed refracture of the same vertebra after PVP with an incidence rate of 0.56% (10 in 1,800). The mean age of the ten patients (nine females and one male) was 79.6 years, and the mean BMI is 22.3. Levels of refracture after PVP were all located in the thoracolumbar junction (T12-L2): three in T12; four in L1; and three in L2. Osteonecrosis was present in all patients and intradiscal cement leakage was noted in five patients. The mean of the restoration of kyphosis angle was 7.7° and height of the anterior border was 26%. Osteonecrosis, greater anterior vertebral height restoration, lesser kyphosis angle correction and cystic filling pattern were statistically significant. CONCLUSIONS: Our study suggests that larger height restoration and solid lump filling cement are risk factors of refracture of cemented vertebral bodies. Symmetric cement distribution and fluid aspiration would be the potential ways to avoid refracture of cemented vertebral bodies.