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Objective: To elucidate the relationship between spino-pelvic sagittal balance parameters and lumbar intervertebral disc degeneration of each segment through retrospective analysis in lumbar degeneration patients., Methods: Retrospective analysis was conducted for the follow-up data in 126 patients with lumbar degenerative disease from July 2009 to June 2012. There were 38 cases with whole spine plates and 88 cases with lumbar plates. All of them received magnetic resonance imaging (MRI) scans. Through software Image J, the following spino-pelvic sagittal balance parameters were measured: sagittal vertical axis (SVA, distance between C7 plumb line and posterior upper corner of S1 endplate), thoracic kyphosis (TK, T5-T12 Cobb angle), thoracolumbar kyphosis (TLK, T10-L2 Cobb angle), lumbar lordosis (LL, L1-L5 Cobb angle), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), T1 spino-pelvic inclination (T1-SPI), T9 spino-pelvic inclination (T9-SPI), spino-sacral angle (SSA), spino-pelvic angle (SPA) and C7 tilt (C7T). Based on the grading system of Pfirrmann et al, the intervertebral disc degeneration grades were acquired for each lumbar segment. According to the normal range of previous studies, each spino-pelvic sagittal balance parameter was classified into 3 groups, i.e. Group A (less than normal), Group B (normal) and Group C (more than normal). All statistical analyses were performed to compare the differences of each lumbar segment/intervertebral disc degeneration among groups by one-way ANOVA test via SPSS 18.0. And P-value < 0.05 was deemed significant., Results: PI had a significant impact on the L5/S1 disc degeneration. And L5/S1 disc degeneration had a significant impact on sagittal balance. Among 57 cases of large PI, LL, PT, SS, SVA, C7T, SPA in L5/S1 of mild-to-moderate and severe degeneration groups was 36.91 ± 14.93 and 29.71 ± 11.30 (P = 0.045), 18.82 ± 8.27 and 25.18 ± 10.19 (P = 0.012), 39.45 ± 8.82 and 34.57 ± 8.88 (P = 0.042), 23.04 ± 26.63 and 62.15 ± 33.82 (P = 0.002), 88.85 ± 3.13 and 83.98 ± 4.62 (P = 0.003), 157.88 ± 11.20 and 147.75 ± 13.98 (P = 0.043) respectively. TLK in L1/L2 with mild-to-moderate and severe degeneration groups was 4.59 ± 7.81 and 14.91 ± 14.75 (P = 0.026). All of L1/L2, L2/L3 and L3/L4 disc degeneration had a significant impact on SPA. SPA in L1/L2, L2/L3, and L3/L4 with mild-to-moderate and severe degeneration groups was 158.47 ± 11.97 and 147.84 ± 12.72 (P = 0.031), 159.91 ± 10.78 and 148.75 ± 13.17 (P = 0.024), 158.46 ± 10.86 and 148.61 ± 13.93 (P = 0.047) respectively., Conclusion: With an important impact on lumbar disc degeneration, PI, either too big or too small, may predispose to the occurrences of lumbar disc degeneration. L5/S1 disc degeneration has a significant impact on pelvis postural parameters (PT, SS). L5/S1 degeneration is a key causative factor of pelvic posterior rotation and compensatory process. L5/S1 disc degeneration has an important impact on pelvis overall parameters (SVA, SPA, C7T). And the degeneration of L5/S1 is a key cause of trunk imbalance.

Objective: To evaluate the correlation of spinal sagittal imbalance and life quality., Methods: Radiographic analysis for 48 consecutive symptomatic patients with spinal sagittal imbalance was performed with posteroanterior and lateral standing radiographs. There were 12 males and 36 females with an average age of (66.2 ± 8.5) yrs. The measurement parameters included C7PL, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI) and sacral slope (SS). Life quality was assessed with SF-36 questionnaire. Pearman's method was employed to analyze the correlation., Results: Mean C7PL was (44.7 ± 22.5) mm, TK (26.1 ± 13.1)°, TLK (11.9 ± 10.3)°, LL (23.5 ± 18.2)°, PT (32.1 ± 13.4)°, PI (57.4 ± 10.9)° and SS (22.5 ± 11.5)°. C7PL had a significant correlation with physical functioning (r = -0.428, P < 0.01) and general health (r = -0.428, P < 0.01). PI had a significant correlation with bodily pain (r = -0.374, P < 0.01), vitality (r = -0.303, P < 0.01), social functioning (r = -0.309, P < 0.01) and role emotional (r = -0.429, P < 0.05). TK had a significant correlation with physical functioning (r = -0.292, P < 0.05) and general health (r = -0.389, P < 0.01). LL had a significant correlation with physical functioning (r = 0.428, P < 0.01), general health (r = 0.340, P < 0.05) and vitality (r = 0.373, P < 0.01). PT had significant correlation with vitality (r = -0.385, P < 0.01) and social functioning (r = -0.417, P < 0.05). No significant correlation existed between TLK, SS and SF-36 categories., Conclusion: C7PL, TK, LL, PI and PT are significant parameters correlating with quality of life. PI is the most important one affecting bodily pain. TK, LL and C7PL are the main parameters affecting general health. PI, PT and LL affect vitality the most. Correcting these parameters while treating sagittal imbalance is important for a better life quality.

Objective: To investigate vertebral augmentation with a novel reticulate bone filling container system by polymethyl methacrylate (PMMA) injection in cadaveric simulated vertebral compressive fracture and explore the effect of reticulate bone filling container on cement distribution controlling within vertebral body and the restoration of biomechanical properties after augmentation., Methods: A total of 28 freshly frozen human vertebrae specimens were randomly divided into 4 groups. After the measurements of bone mineral density (BMD) and vertebral height, each vertebra received an axle load by a MTS (material testing system) machine to test the initial strength and stiffness. Subsequently a simultaneous compressive fracture model was created to measure the stiffness and height of fractured vertebrae. Then the augmentation procedure was performed. Afterward the biomechanical properties and the vertebral height were similarly measured as pre-operatively. The expansion of bone filling container and the distribution of cement within vertebral body were morphologically observed by crossing the specimens in sagittal midline and also integrated with the radiographic results., Results: Stiffness was significantly restored comparing with that of fractured level (P < 0.05). And the bipedicular groups had better restoration results than the unipedicular groups. The strength and height of specimens significantly increased after the augmentation procedure but without difference among groups. In axial radiographic view, the distribution of cement in vertebral body was oval or long oval-shaped in double-layer bone filling container groups while it was irregular in single-layer groups. After crossing, the double-layer version expanded well in vertebral body and could enwrap most of injected cement. There was only a little leakage near the vessel layer. But the single-layer version had a poor expansion and a large amount of cement leakage., Conclusion: This novel reticulate bone void filling container system with different layers may restore both the biomechanical properties and the height of fractured vertebrae. But, with the benefit of reducing cement leakage, a double-layer design can enwrap most of injected PMMA and has a brighter prospect of clinical application.

Objective: To evaluate the predictive values of Tokuhashi score, revised Tokuhashi score and Tomita score systems for life expectancy and treatment options in patients with spinal metastasis., Methods: From February 1996 to January 2009, spinal operations in 104 cases with spinal metastasis were performed in our hospital. There were 65 males and 39 females, with an average of 53.4 years (median 52.5 years). To calculate AUC (area under the curve) values of Receiver Operating Characteristic (ROC) curves of three scores, and to analyze the accuracy of prediction of life expectancy. To compare the actual survival time with the expected survival time of the three scores by Kaplan-Meier method. Spearman correlation analysis was performed between the survival time and three scoring systems., Results: All cases were followed-up with an average duration of 10.9 months, and 77 patients died. AUC analysis of ROC curves showed that the difference of the accuracy of the three scores was not significant. AUC in all groups of Tokuhashi Score was low, with a poor diagnostic accuracy. In the "died within 3 months" and "died within 6 months" groups of revised Tokuhashi score, the accuracy was low, while high in the other two groups. The AUC values of Tomita score in "died within 6 months" and "died within 24 months" were high, with a great diagnostic accuracy while the other two groups were low with a low diagnostic accuracy. Kaplan-Meier survival curve analysis showed that the actual survival time in all three scores was not entirely consistent with the expected survival time. Tokuhashi score and revised score were positively correlated with the survival time while that of Tomita score was negative., Conclusion: All the three prognosis scores in patients with spinal metastasis were closely related with survival time. The combination of Tokuhashi score and Tomita score may be applied to better predict postoperative survival prognosis and guide the surgical options for patients with spinal metastasis.

Objective: To evaluate of the role of transcranial electrical stimulation motor evoked potential (TES-MEP) in combination with cortical somatosensory evoked potential (CSEP) monitoring during the spinal surgery., Methods: TES-MEP on bilateral anterior tibial muscle and flexor hallucal brevis and CSEP on bilateral posterior tibial nerve were observed simultaneously on 293 patients during spinal surgery from July 2006 to April 2009. Intravenous anesthesia was employed in all the patients, a part of which were added low dose of sevoflurane or muscle relaxant. The results of TES-MEP, CSEP and combined monitoring were analyzed statistically. Pre-operative and post-operative motor and sensory functions of spinal cord were compared., Results: Success rate of TES-MEP, CSEP and combined monitoring was 90.8%, 96.9% and 100% respectively. For the judgment of motor function of spinal cord, the sensitivity of TES-MEP and CSEP was 100% and 89.3% respectively and the specificity of 98.4% and 96.9%. The Youden index of the two methods was 0.984 and 0.862. For sensory function, the sensitivity of them was 76.7% and 93.3% respectively and the specificity of 98.7% and 98.0%. The Youden index was 0.754 and 0.913. The sensitivity of combined monitoring was 100%, with the specificity of 96.9%. The Youden index was 0.969., Conclusions: The precision of monitoring motor function of spinal cord with TES-MEP is higher than that with CSEP, however, for sensory function, CSEP is more precise. The sensitivity and precision of combined monitoring for spinal cord function were apparently better than that of unitary TES-MEP or CSEP. The combined TES-MEP and CSEP monitoring is a relatively ideal method.

Objective: To evaluate the efficacy of hBMP-4 gene modified tissue engineered bone graft in the enhancement of rabbit spinal fusion and find an ideal kind of substitute for the autograft bone., Methods: Rabbit BMSCs were cultured and transfected with AAV-hBMP-4 using different MOI value. The optimal MOI value were determined by observing cell's morphology change. BMSCs were then transfected with AAV-hBMP4 and AAV-EGFP respectively, following which the transfected cells were evenly suspended in a collagen sponge I, and implanted to either side of the L5,6 intertransverse spaces posterolateral in the New Zealand rabbits to induce spinal fusion. Fourteen rabbits were randomly divided into 2 groups. Group 1: AAV-hBMP-4 transfected BMSCs in the right side (hBMP-4 side) and autograft bone in the left side. Group 2: AAV-hBMP-4 transfected BMSCs in the right side (hBMP-4 side) and AAV-EGFP transfected BMSCs in the left side (EGFP side). Radiographs and three-dimensional CT of the spine, manual palpation, gross and histological examination of the fusion masses for all the animals were performed subsequent to animals having been sacrificed at 12 weeks after surgery., Results: Evaluation has been taken in 12 New Zealand rabbits delivered into 2 groups which meet the criterion after operation. Eleven in 12 implemented sides involved hBMP-4 achieved bony fusion, to which 5 in 6 autografted sides was similar. But only 2 in 6 sides in EGFP-group achieved bony fusion meanwhile. Three-dimensional CT scan and palpation also evidenced the results. Bone formation was observed obviously on specimen both in hBMP4 sides and autografted ones. EGFP-group also got bony integration, but the quantity was small., Conclusion: Tissue-engineered bone graft constructed from application of hBMP4 is a fine substitute for autograft. Effective enhancement of bony integration in spinal fusion surgery has been evidenced in vivo.

Objective: To biomechanically compare the stability of the short and long iliac screw fixation constructs in lumbo-iliac reconstruction., Methods: Seven adult human embalmed cadavers (L(3)-pelvis) were used. Using posterior spinal fixation system, L(4)-S(1) pedicle screw fixation was performed. This was defined as intact state of the sacroiliac joint. After the intact test, total sacrum resection and L(4)-L(5)-pelvis reconstruction by pedicle screw and iliac screw with different lengths were performed as follow: short screw group (as the length of exceeding 2 mm over ischial notch) and long screw group (as the length of exceeding 2 mm over anterior inferior iliac spine). Using the 858 MTS material testing machine, biomechanical testing was performed under 800 N compression and 7 Nm torsion loading modes. At last, the axial pullout test of two iliac screws was executed. Construct stiffness in compression and torsion test, and maximum pullout force were analyzed., Results: Insertion lengths of the short and long iliac screw were (70 +/- 2) mm and (138 +/- 4) mm respectively. The lumbo-pelvic reconstruction using short and long iliac screw, respectively restored 53.3% +/- 13.6% and 57.6% +/- 16.2% of the initial stiffness in compression testing, and respectively harvested 55.1% +/- 11.9% and 62.5% +/- 9.2% of the initial stiffness in torsion testing. No significant difference was detected between the two reconstructions (P > 0.05), however, the compressive and torsional stiffness of the two techniques were markedly less than the intact condition (P < 0.05). The maximum pullout strength of long iliac screw was significantly higher than short screw (P < 0.05)., Conclusions: Under the physical loading, lumbo-pelvic fixation construct using the short iliac screw may obtain mechanical stability comparable to that by long iliac screw. The short iliac screw is only the half of the long iliac screw by length, could reduce the implantation risk. However, the long iliac screw behaves greater axial pullout force, should be applied as far as possible in the osteoporosis patient. The lumbo-pelvic reconstruction utilizing any length of iliac screw is difficult to restore the local stability.

Objective: To build sub-endplate microcirculation disturbance animal model and to investigate the potential pathogenesis of intervertebral disc degeneration (IVDD)., Methods: Twenty four New Zealand white rabbits were divided into treatment group (Group A) and control group (Group B). In Group A, animals received endotoxin and corticosteroid application to build sub-endplate microcirculation disturbance animal model, validated by microthrombus staining. In Group B, animals were given no drug, but standard feeding. After 3 month, the extent of IVDD was evaluated by the water content, biochemistry analysis, and morphology., Results: Sub-endplate microthrombus staining confirmed the exist of microcirculation disturbance. The water content and biochemistry components content of disc in Group A were lower than those of disc in Group B, and IVDD was observed in morphology., Conclusion: Sub-endplate microcirculation disturbance can directly contribute to IVDD, the nutrients diffusion barrier is the potential pathogenesis of IVDD.

Objective: To explore how to determine painful vertebrae treated by kyphoplasty in multiple-level osteoporotic vertebral compression fractures and clinical outcome., Methods: From October 2002 to June 2005, 51 consecutive procedures with kyphoplasty were performed on 35 patients with multiple-level osteoporotic vertebral compression fractures. There were 51 painful vertebrae among 120 vertebral compression fractures. The painful vertebra was determined by the signal intensity changes in MR images, combined with radiography and local percussion pain before operation. Only painful vertebrae were treated by kyphoplasty. Preoperative, postoperative and final follow-up visual analog scale (VAS) and radiographic findings such as vertebral height and Cobb angle were recorded and analyzed., Results: All patients tolerated the procedure well with immediate relief of their back pain after kyphoplasty and they can walk at 1-3 days after the procedure. There were 3 vertebrae (3/51) occurred asymptomatic extravasation of cement. 31 cases were followed up for mean 16.2 months (range 6-44 months). VAS reduced from preoperative 8.7 to final follow-up 2.1 (P <0. 01). At final follow-up the vertebral height had a recovery rate of 59.17%, and the mean Cobb angle was improved 10.1 degrees. There was a significant improvement between preoperative and final follow-up values (P < 0.01)., Conclusions: The painful vertebra can be determined by signal intensity changes in MR series images in multiple-level osteoporotic vertebral compression fractures. Selecting painful vertebrae to be treated by kyphoplasty can make patients with multiple-level VCFs gain an excellent result.

Objective: To observe the effect and safety of one-stage single balloon multiple expansions percutaneous kyphoplasty (PKP) in treatment of osteoporotic vertebral compressive fracture (OVCF) and spinal tumor., Methods: One-stage single balloon multiple expansions PKP was performed on 18 patients, 5 males and 13 females, aged 68.77 (44 - 80), with 45 vertebrae, including 11 case of OVCF (with 29 diseased vertebrae), 11 cases of multiple vertebral fracture (with 19 diseased vertebrae), 5 cases of multiple myeloma (with 12 diseased vertebrae), and 2 case of spinal metastatic tumor (with 4 diseased vertebrae), the vital signs were record during operation. Pain relief and functional recovery were evaluated with visual analogue pain scale (VAS) and Oswestry disability index (ODI) scaling, and restoration of vertebral height and Cobb angle were evaluated by X-ray examination. Follow-up was conducted by telephone survey or clinic consults for 12.3 months (6 - 18 months)., Results: Operation was successfully performed on all patients with an operative time of 29.3 min (55 - 127 min) per vertebra. The average pressure of the balloon expansion was 165 Psi (87 - 210 Psi), and the average balloon expanded volume was 3.25 ml (1.5 - 4 ml). A balloon was expanded 2 approximately 5 times in one operation with the average of 2.94 expanded times. The bone cement volume injected was 3.95 ml (2 - 8.5 ml) per vertebra. Epidural cement leakage was seen in 1 vertebra in 1 case and paraspinal leakage was seen in two vertebrae in 1 case. The VAS and ODI scoring of these patients were both decreased significantly after operation. Both the anterior height and midline height of vertebrae were significantly improved. The pain relief and functional recovery were substantial and maintained to the last follow-up without any re-collapse or adjacent level fracture., Conclusion: one-stage single balloon multiple expansions PKP is effective, economic and safe in treatment of multi-level OVCF and spinal tumor.

Objective: To investigate the appropriate ratio of liquid/powder and use of radiopaque agent in EH composite material for percutaneous vertebroplasty (PVP)., Methods: (1) EH composite material was divided into 6 groups. The material without contrast with the liquid/powder ratios 8:9, 8:8, and 8:7 was classifieds as groups I, II, and III; and the EH composite material with the liquid/powder ratios 8:9, 8:8, and 8:7 and with the addition of 20% barium sulfate by weight was classified as the groups IV, V, and VI. The curing temperature was measured. The bone cement of different groups was made into cylinders to be X-rayed to observe the opacity. Universal tester was used to examine the strength and stiffness. (2) The vertebrae (T8 approximately L5) were isolated from the cadaver of an elder female patient with osteoporosis. Universal tester was used to examine the strength and stiffness of the vertebral bodies (VBs). Osteoporotic vertebral compression fracture (OVCF) model was made. PVP procedure was mimicked by puncturing through the bilateral pedicle of vertebral arch into the anterior 1/3 of the vertebral bodies and the EH composite materials of the groups II and V were injected into the VBs Then the temperatures of the geometric center (CT) and spinal canal posterior wall (PT) of the VBs were measured in a water bath with the temperature of 37 degrees C. Twenty-four hours later the vertebrae underwent X-ray examination to observe the opacity and underwent examination of strength and stiffness with universal tester., Results: (1) The sticking periods (?) of the groups IV, V, and VI were significantly longer than those of the corresponding groups I, II, and III respectively by about 60 s, and the highest temperature of the groups IV, V, and VI were significantly lower than those of the corresponding groups I, II, and III respectively. Addition1 of barium sulfate increased the opacity of the bone cement, but did nor significantly influence the strength of the bone cement. The properties of the group V was the best. (2) The bone cement was easy to be injected into the VBs. The peak PT was not beyond 50 degrees C. After the injection of the bone cement of the groups II, the strength and stiffness of the VB were (1501.6 +/- 5.0) N/mm and (285.6 +/-) N/mm, both significantly higher than those before the injection [(547.5 +/- 3.1) N/mm and (104.1 +/- 1.3) N/mm]; and after the injection of the bone cement of the groups V, the strength and stiffness of the VB were (1355.0 +/- 4.5) N/mm and (257.7 +/- 1.9), both significantly higher than those before the injection [(543.8 +/- 2.7) N/mm and (103.4 +/- 1.1) N/mm]. The opacity of the VBs injected with the bone cement of the group V was better than those injected with the bone cement of the group II., Conclusion: The EH (8/8) with 20% barium sulfate is a proper and effective filling material for the treatment of OVCF.

Objective: To compare the clinical results of balloon percutaneous kyphoplasty (PKP) and "Sky-bone expander" PKP., Methods: From October 2004 to February 2006, 25 cases (57 vertebrae) balloon PKP and 24 cases (29 vertebrae) "Sky-bone expander" PKP procedures were performed. The operation time, bleeding volume, cement injected volume were recorded during operation. The patients' pain relief and functional activities recovery were evaluated after operation. The distribution of the cement and the restoration of vertebral height were also observed post-operation. All these patients were followed-up by telephone or clinic consults after discharged., Results: All cases were successfully experienced procedures. There are no significant differences in operative time, bleeding volume and cost of every vertebrae in these two group (P > 0.05). The balloon group had larger cement injected volume per pedicle than Sky group (4.27 +/- 1.08) ml vs. (3.15 +/- 0.78) ml (P < 0.05). The VAS and ODI scoring of these two groups were both decreased significantly after operation. The vertebral height were restored in both two groups with anterior height and midline height restored significantly in balloon group and midline height restored significantly in Sky group. The cement distribution of "Sky-bone expander" PKP with unipediclar injection mostly limited in the injective side of the vertebral body, but most of the balloon PKP vertebrae with unipediclar injection can be seen a cross-midline cement distribution in the anterior-posterior position X ray film., Conclusions: Both balloon PKP and "Sky-bone expander" PKP are efficacious and safety in the treatment of vertebral compression fractures. "Sky-bone expander" PKP is more suitable for single level compressive fracture while balloon PKP is especially suitable for multiple level compressive fractures.