Effects of expandable graphite on the flame-retardant and mechanical performances of rigid polyurethane foams.

Polyurethane foams (PUFs) are found everywhere in our daily life, but they suffer from poor fire resistance. In this study, expansible graphite (EG) as flame retardant was incorporated into PUFs to improve material fire resistance. With the presence of EGs in the PU matrix, bubble size in PUF became smaller as confirmed by the scanning electron microscopy. The mass density of PUFs is directly proportional to the content of EG additive. The compression strengths of EG0/PUF and EG30/PUF decrease from 0.51 MPa to 0.29 MPa. The Fourier transform infrared spectroscopy (FTIR) analysis of RPUFs showed that the addition of EGs did not change the functional group structures of RPUFs. Thermo-gravimetric analysis (TGA) testing results showed that the carbon residue weight of EG30/PUF is higher than other PU composite foams. The combination of TGA and FTIR indicated that the EG addition did not change the thermal decomposition products of EG0/PUF, but effectively inhibited its thermal decomposition rate. Cone calorimeter combustion tests indicated that the peak of the heat release rate of EG30/PUF significantly decreased to 100.5 kW m-2compared to 390.6 kW m-2for EG0/PUF. The ignition time of EG/PUF composites also increased from 2 s to 11 s with incorporation of 30 wt% EGs. The limiting oxygen index (LOI) and UL-94 standard tests show that the LOI of EG30/PUF can reach 55 vol%, and go through V-0 level. This study showed that adding EG into PU foams could significantly improve the thermal stability and flame retardancy properties of EG/PUF composites without significantly sacrificing material compression strength. The research results provide useful guidelines on industrial production and applications of PUFs.

A comparative study for the usage of Fidji cervical cages after multilevel anterior cervical discectomy and fusion.

BACKGROUND: Postoperative dysphagia is one major concern in the treatment for patients with cervical spine spondylosis by using anterior cervical discectomy and fusion (ACDF) with plating and cage system. PURPOSE: To evaluate the influence of two types of surgery for multilevel cervical spondylotic myelopathy (CSM) on postoperative dysphagia, namely ACDF with cage alone (ACDF-CA) using Fidji cervical cages and ACDF with cage and plate fixation (ACDF-CP). METHODS: A retrospective study was performed in 62 consecutive patients with multilevel CSM, including 32 underwent ACDF-CA (group A) and 30 underwent ACDF-CP (group B). All enrolled patients were followed up at 48 h, 2 months and 6 months postoperatively, when the dysphagia rate, Swallowing-Quality of Life (SWAL-QOL) score and the thickness of prevertebral soft tissue were recorded. RESULTS: At 48 h and 2 months, the dysphagia rate and thickness of prevertebral soft tissue were both significantly lower in group A than in group B, while the SWAL-QOL score of group A was significantly higher than that of group B. No significant difference was observed at 6 months. CONCLUSION: Fidji cervical cages could relieve postoperative dysphagia in the treatment of multilevel CSM with ACDF, especially at the first several months postoperatively.

Comparison of outcomes between minimally invasive transforaminal lumbar interbody fusion and traditional posterior lumbar intervertebral fusion in obese patients with lumbar disk prolapse.

OBJECTIVE: The aim of this study was to compare the curative effect between minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and the posterior lumbar interbody fusion (PLIF) in obese patients with lumbar disk prolapse. PATIENTS AND METHODS: In this study, 72 patients who underwent lumbar disk prolapse therapy in the Third Hospital of Hebei Medical University between March 2011 and 2015 were retrospectively analyzed and were divided into two groups, MIS-TLIF group (n=35) and PLIF group (n=37), according to different surgical procedures. Several clinical parameters were compared between these two groups. RESULTS: Compared with PLIF, MIS-TLIF was associated with longer operative time, less blood loss, less postoperative drainage and shorter postoperative time in bed; moreover, patients in the MIS-TLIF group had lower levels of serum creatine kinase on 1, 3 and 5 postoperative days. At the 3- and 6-month follow-up, Visual Analog Scale (VAS) scores of low back pain of patients in the MIS-TLIF group were significantly reduced and Japanese Orthopaedic Association (JOA) scores were increased, whereas the Oswestry Disability Index (ODI) showed no significant difference between the two groups. CONCLUSION: Obese patients can achieve good efficacy with MIS-TLIF or PLIF treatment, but MIS-TLIF surgery showed longer operative time, fewer traumas and bleeding volume, less incidence of short-term pain, low complication rate and faster postoperative recovery.

Analysis of the clinical effects of transforaminal endoscopic discectomy on lumbar disk herniation combined with common peroneal nerve paralysis: a 2-year follow-up retrospective study on 32 patients.

BACKGROUND: Very few studies have discussed transforaminal endoscopic discectomy (TED) in the treatment of common peroneal nerve paralysis induced by lumbar disk herniation (LDH). This study aimed to evaluate the efficacy of TED in the treatment of LDH combined with common peroneal nerve paralysis. MATERIALS AND METHODS: The clinical and follow-up data of 32 patients with common peroneal nerve paralysis induced by LDH undergoing TED from March 2011 to April 2014 were retrospectively analyzed in this study. Follow-up was conducted immediately after the surgery, as well as 3, 12, and 24 months postoperatively. The parameters (including muscle strength recovery of the anterior tibial muscle, leg pain visual analog scale score, neurological function Japanese Orthopaedic Association [JOA] score, MacNab scores in the last follow-up, and the intraoperative and postoperative complications) were recorded. RESULTS: Three patients (9.4%) had the anterior tibial muscle strength recovered to ≥ grade 4 immediately after the surgery. The anterior tibial muscle strength of patients recovered to basically stable form in the 6-month postoperative follow-up and that in the last follow-up were as follows: one case of grade 1, one case of grade 2, 28 cases of grade 4, and two cases of grade 5. The visual analog scale scores of leg pain were significantly reduced immediately after the surgery and also on 3, 12, and 24 months compared with preoperative period (all P<0.05). The postoperative JOA scores in the last follow-up were significantly higher than the preoperative JOA scores (P<0.05), and there were nine excellent cases (28.2%), 21 good cases (65.6%), one fair case (3.1%) and one poor case (3.1%) in the last follow-up, with an overall excellent and good rate of 93.8%. CONCLUSION: TED, which can offer sufficient decompression of the nerve root, has excellent overall clinical effects in treating common peroneal nerve paralysis induced by LDH.

Suprapedicular Foraminal Endoscopic Approach to Lumbar Lateral Recess Decompression Surgery to Treat Degenerative Lumbar Spinal Stenosis.

BACKGROUND To discuss the strategy of suprapedicular foraminal endoscopic approach to lumbar lateral recess decompression and evaluate the safety and effectiveness of this strategy. MATERIAL AND METHODS Complete clinical information of 52 cases of lumbar lateral recess decompression with therapy of suprapedicular foraminal endoscopic approach were analyzed during the period from February 2010 to April 2014 in the Third Hospital of Hebei. All patients were followed up for 24 months, and VAS, JOA, ODI, and LRD were compared between preoperative and postoperative therapy and changes of FA. Intraoperative and postoperative complications were recorded and the safety of the surgery was evaluated. The surgical "excellent" and "good" rates were evaluated using MacNab score. RESULTS VAS scores for lumbago and leg pain at 3, 6, 12, and 24 months after surgery were significantly lower than before surgery (p<0.05). JOA scores at 12 and 24 months after surgery were significantly higher than before surgery (p<0.05). ODI at 12 and 24 months after surgery were significantly lower than before surgery (p<0.05). LRD after surgery was higher (p<0.05), and FA was lower than before surgery. CONCLUSIONS Use of the suprapedicular foraminal endoscopic approach to lumbar lateral recess decompression is safe and effective, and this minimally invasive treatment can achieve satisfactory results, especially for elderly patients with complicated underlying diseases.

True anteroposterior view pedicle screw insertion technique.

BACKGROUND: The wide use of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery in the treatment of degenerative disc disease of lumbar spine in spinal surgery highlights the gradual decrease in the use of traditional pedicle screw insertion technology. This study aims to analyze the accuracy of the true anteroposterior view pedicle screw insertion technique in MIS-TLIF surgery, compare it with conventional pedicle screw insertion technology, and discuss its clinical application value. METHODS: Fifty-two patients undergoing true anteroposterior view (group A) and 87 patients undergoing conventional pedicle screw insertion (group B) were diagnosed with lumbar disc herniation or lumbar spinal stenosis. Time for screw placement, intraoperative irradiation exposure, accuracy rate of pedicle screw insertion, and incidence of neurovascular injury were compared between the two groups. RESULTS: The time for screw placement and intraoperative irradiation exposure was significantly less in group A. Penetration rates of the paries lateralis of vertebral pedicle, medial wall of vertebral pedicle, and anterior vertebral wall were 1.44%, 0%, and 2.40%, respectively, all of which were significantly lower than that in group B. No additional serious complications caused by the placement of screw were observed during the follow-up period in patients in group A, but two patients with medial penetration underwent revision for unbearable radicular pain. CONCLUSION: The application of true anteroposterior view pedicle screw insertion technique in MIS-TLIF surgery shortens time for screw placement and reduces the intraoperative irradiation exposure along with a higher accuracy rate of screw placement, which makes it a safe, accurate, and efficient technique.

Evaluation of Transforaminal Endoscopic Discectomy in Treatment of Obese Patients with Lumbar Disc Herniation.

BACKGROUND This study aimed to evaluate the efficacy of transforaminal endoscopic discectomy (TED) in the treatment of obese patients with lumbar disc herniation (LDH). MATERIAL AND METHODS A total of 69 obese patients with LDH (35 males and 34 females; age range, 24 to 43 years; median age, 34 years) were included in this study. These patients had undergone TED from March 2011 to December 2015 in the Third Hospital of Hebei Medical University. Their clinical and follow-up data were prospectively analyzed. The degree of pain and disability were measured on the basis of the Visual Analog Scale (VAS) at 1 day before surgery, immediately after surgery, and 3 months after surgery. Neurologic functions were measured on the basis of the Japanese Orthopaedic Association (JOA) system 1 day before surgery and 3 months after surgery. The MacNab score at last follow-up was recorded to evaluate the early clinical efficacy. Complications during and after the operation were recorded to evaluate the safety of surgery. RESULTS Two patients experienced abnormal sensations in the export nerve root zone postoperatively, which disappeared after 3 days of treatment with dehydration and administration of hormone (dexamethasone). Three cases of recurrence were observed at 6 months, 7 months, and 9 months postoperatively; they were scheduled to receive total laminectomy combined with bone grafting internal fixation. A total of 67 patients were followed up for 3-23 months and mean follow-up was 11.8 months. The VAS scores at postoperative 3 months and 1 year were significantly reduced compared to that before the operation, with significant differences between them (t=43.072, P<0.05; t=43.139, P<0.05). The JOA scores at last follow-up postoperatively was significantly higher than that before surgery (t=-60.312, P<0.05). At the last follow-up, 17 cases (25.3%) had excellent outcomes, 39 (58.2%) good, 7 (10.4%) fair, and 4 (5.9%) poor. Overall, 83.5% of patients had excellent or good rates. CONCLUSIONS The early efficacy of TED is relatively good and safe for the selected obese patients with LDH in this study. Larger-sample studies with longer duration and follow-up are required to detect the safety and effectiveness of TED.

Prevalence and risk factors of deep vein thrombosis in patients after spine surgery: a retrospective case-cohort study.

Deep vein thrombosis (DVT) is common seen in patients undergoing spine surgery. However, its prevalence and associated risk factors have not been well understood yet. This retrospective case-cohort study was designed to investigate risk factors for postoperative DVT using retrospectively collected data from department of spine surgery between 07/2013 and 07/2014. Univariate analysis and binary logistic regression analysis were used to determine risk factors for DVT. A total of 861 patients were admitted into DVT-associated analyses, including 410 males and 451 females, aged from 15 to 87 years old (median 54, IQR 18). Of them, 147 cases (17%) sustained postoperative DVT. DVT incidence was 15.9% in patients undergoing lumbar interbody fusion, 13.5% in patients treated by low-molecular-weight heparin (LMWH), while only 8.1% in patients without LMWH. However, it revealed no significant difference between LMWH group and non-LMWH group (χ(2) = 1.933, p = 0.164). Logistic regression equation was logit P = -4.09 + 0.05*X1 - 0.55*X2 + 0.41*X3 + 1.41*X7, (X1 = age; X2 = regions; X3 = hypertension; X7 = D-dimer). In this study, LMWH prophylaxis after spine surgery proved ineffective. Advanced age, D-dimer and hypertension have proved to be the risk factors for postoperative DVT in patients undergoing spine surgery.

Unilateral posterior vertebral column resection for severe thoracolumbar kyphotic deformity caused by old compressive vertebrae fracture: a technical improvement.

Severe thoracolumbar kyphotic deformity caused by old compressive vertebrae fracture remains a big challenge for spine surgeons. When symptoms related to significant deformities cannot be adequately managed conservatively, posterior vertebral column resection (PVCR) is required, but with long operating time and severe blood loss. We develop a UPVCR technique, which is done through a unilateral approach instead of a bilateral approach, vertebral body resection advancing to cross the midline in an abrasive way from an extreme oblique orientation enable the resection of most contralateral vertebral body. In the present study, the effects of UPVCR for severe thoracolumbar kyphotic deformity were investigated. We did find that satisfactory correction of sagittal deformity, functional improvement and pain relief can be achieved by UPVCR, and it has the advantage of shortening surgery time, reducing blood loss and incidence of nerve root impingement over PVCR.

17ß-estradiol protects against apoptosis induced by interleukin-1ß in rat nucleus pulposus cells by down-regulating MMP-3 and MMP-13.

In our previous study, 17ß-estradiol was proved to protect rat annulus fibrosus cells against apoptosis induced by interleukin-1ß (IL-1ß). However, whether 17ß-estradiol has protective effect on rat nucleus pulposus cells remains unclear. The purpose of this study was to further explore the effects of 17ß-estradiol on rat nucleus pulposus cells based on IL-1ß-induced apoptosis. TUNEL assay and Annexin V/PI double staining were used to detect apoptosis and revealed that IL-1ß induced notable apoptosis, which was reversed by 17ß-estradiol. Meanwhile, cell viability and binding ability were decreased by IL-1ß, but activated caspase-3 was increased. However, all of the detected effects of IL-1ß were eliminated by 17ß-estradiol. Furthermore, real-time quantitative RT-PCR was used to further find that IL-1ß downregulated expression level of type II collagen, aggrecan, tissue inhibitor of matrix metalloproteinase (TIMP)-1, while upregulated matrix metalloproteinase (MMP)-3, MMP-13 and Bcl-2, which was further confirmed by western blot. Finally, 17ß-estradiol was proved to abolish the above negative effects of IL-1ß. In summary, this work presented that IL-1ß maybe induced apoptosis of rat nucleus pulposus cells, which was resisted by 17ß-estradiol by down-regulating MMP-3 and MMP-13 via a mitochondrial pathway. This research provides a novel insight into the anti-apoptotic effect of 17ß-estradiol on IL-1ß-induced cytotoxicity, and may potentially lead to a better understanding of the clinical effects of 17ß-estradiol, especially in terms of intervertebral disc degeneration.

17ß-Estradiol protects against apoptosis induced by levofloxacin in rat nucleus pulposus cells by upregulating integrin α2ß1.

Levofloxacin has been reported to have cytotoxicity to chondrocytes in vitro. And 17ß-estradiol has been widely studied for its protective effects against cell apoptosis. Based on apoptotic cell model induced by levofloxacin, the purpose of this study was to explore the mechanism by which 17ß-estradiol protects rat nucleus pulposus cells from apoptosis. Inverted phase-contrast microscopy, flow cytometry, and caspase-3 activity assay were used to find that levofloxacin induced marked apoptosis, which was abolished by 17ß-estradiol. Interestingly, estrogen receptor antagonist, ICI182780, and functional blocking antibody to α2ß1 integrin, both prohibited the effect of 17ß-estradiol. Simultaneously, levofloxacin decreased cellular binding ability to type II collagen, which was also reversed by 17ß-estradiol. Furthermore, western blot and real-time quantitative PCR were used to find that integrin α2ß1 was responsible for estrogen-dependent anti-apoptosis, which was time-response and dose-response effect. 17ß-estradiol was proved for the first time to protect rat nucleus pulposus cells against levofloxacin-induced apoptosis by upregulating integrin α2ß1 signal pathway.

[The study on the relationship between modic change and disc height together with lumbar hyperosteogeny].

OBJECTIVES: To evaluate the relationship between Modic change and disc height together with lumbar hyperosteogeny and study the role of Modic change in lumbar degeneration. METHODS: The imaging data of 150 elderly patients with chronic low back pain were analysed retrospectively. All patients underwent MRI and lumbar lateral X-ray examination. The lumbar disc from L1-L2 to L5-S1 were selected for this study, including 750 discs, vertebral and endplate close to disc in 150 patients. The incidence rate of lumbar endplate Modic change, disc height and the degree of vertebral bone hyperplasia were recorded. The ratio of disc height/lumbar intervertebral disc height < 50% was defined as disc collapse. The patients were divided into 4 groups in the basis of imaging changes. Group A1:disc collapse without severe lumbar hyperosteogeny; Group A2: disc collapse with severe lumbar hyperosteogeny; Group B1: Neither disc collapse nor severe lumbar hyperosteogeny; Group B2: severe lumbar hyperosteogeny without disc collapse. The incidence rates of Modic change were compared between the 4 groups by χ(2) test. Finally, the influence of disc height and vertebral bone hyperplasia on the incidence rate of Modic change was analysed. RESULTS: Four groups of patients observed a total of 750 discs. The number of intervertebral discs in the group A1 was 208, the incidence rate was 54.3%. The number of intervertebral discs in the group A2 was 135, the incidence rate of group A2 was 34.8%. The number of intervertebral discs in the B1 group was 225, the incidence rate of group B1 was 16.9%. The number of intervertebral discs in the B2 group was 182, the incidence rate of group B2 was 29.7%. There was significant difference of lumbar endplate Modic change incidence rate among the 4 groups(χ(2) = 69.565, P < 0.05). The results of post hoc test showed that the incidence rate of Modic change in group A1 was higher than group A2, B1 and B2 (χ(2) = 12.524, 66.701 and 24.102, P < 0.00714). There was significant difference of Modic change incidence rate between group A2 and B1(χ(2) = 15.032, P < 0.00714), but there was no significant difference of Modic change incidence rate between group A2 and B2 (χ(2) = 0.945, P > 0.00714) . There was significant difference of Modic change incidence rate between group B2 and group B1 (χ(2) = 9.395, P < 0.00714). CONCLUSIONS: The incidence rate of Modic change with disc collapse but without severe lumbar hyperosteogeny is high in elderly patients with chronic low back pain. There is no significant difference of Modic change incidence between patients with both disc collapse and severe lumbar hyperosteogeny and patients with severe lumbar hyperosteogeny but without disc collapse.

Prognostic value of magnetic resonance imaging combined with electromyography in the surgical management of cervical spondylotic myelopathy.

The present study aimed to evaluate the value of pre-operative magnetic resonance imaging (MRI) combined with electromyography (EMG) for predicting clinical outcome following surgical management of cervical spondylotic myelopathy (CSM). A total of 94 patients with cervical compressive myelopathy were prospectively enrolled and treated with anterior, posterior and posterior-anterior united decompression between October 2007 and February 2009. Prior to surgery 1.5-T MRI and EMG were performed in all patients. The patients were classified into four types based on the presence (+) or absence (-) of an increased signal intensity (ISI) on the T2-weighted magnetic resonance (MR) images and also based on the positive (+)/negative (-) results of the EMG. The four types were as follows: Type I, MRI/EMG (-/-); Type II, MRI/EMG (+/-); Type III, MRI/EMG (-/+); and Type IV, MRI/EMG (+/+). The clinical outcome was also graded according to a modified Japanese Orthopedic Association (JOA) scoring system. Furthermore, pre- and post-operative clinical data were statistically analyzed to explore the correlation between the factors. There were 36 cases (38%) of Type I, 16 (17%) of Type II, 13 (14%) of Type III and 29 (31%) of Type IV. According to the analysis of the clinical data between the four types, there were significant differences in the disability classifications, pre-operative JOA scores and disease duration (P<0.05), but there were no significant differences in gender, age or cord compression ratios (P>0.05). Until the final follow-up, there was a significant difference in the recovery ratio between the four study groups (Hc=27.46, P<0.05). Further comparison showed that the surgical outcome was best in Type I patients and worst in Type IV patients. In conclusion, there was a distinct correlation between classification and the rate of clinical improvement. Patients who had a negative EMG and those without an ISI on T2-weight images tended to suffer only mild symptoms, a short disease duration and, most significantly, experience a good surgical outcome.

[Analysis of axial symptoms after indirect decompression for ossification of the posterior longitudinal ligament of the cervical spine].

OBJECTIVE: To study the etiology and clinical significance of axial symptoms after posterior operative procedures for ossification of the posterior longitudinal ligament (OPLL). METHODS: From February 2005 to February 2010, 76 patients with OPLL treated were retrospectively experienced. There were 34 male and 42 female with average of 52.1 years (range from 37 to 74 years), the average duration of the disease was 32.1 months (range from 11 to 56 months). Nineteen patients underwent traditional laminectomy in group A, 33 patients received open-door laminoplasty in group B and 24 patients underwent lateral mass screw fixation in group C. All patients underwent X-ray examination pre- and post operative, computed tomography were used for diagnosis of OPLL, the recovery rate was calculated using pre- and postoperative Japanese Orthopedic Association (JOA) scores for each patient. Pre- and postoperative cervical curvature index and axial symptoms were measured and compared. χ(2) test and SNK test were used as statistical methods. RESULTS: All patients were followed up for 14 - 35 months, average (21 ± 5) months. Loss of cervical curvature index was 4.2% ± 1.7% in group A, 2.9% ± 2.2% in group B and 2.3% ± 1.9% in group C. The difference was significant in loss of cervical curvature indice between group A and B (q = 2.94, P < 0.01), group A and C (q = 4.23, P < 0.01). The average JOA recovery rate was 58.3% for group A, 64.3% for group B and 66.7% for group C. There was no significant difference in JOA recovery rate among the three groups (P > 0.05). The rate of early evident axial symptoms was 7/19 in group A, 30.3% in group B and 33.3% in group C and the difference was not statistically significant (P > 0.05). The incidence of late evident axial symptoms was 5/19 in group A, 12.1% in group B and 8.3% in group C, the difference was not significant between group B and C (χ(2) = 13.762, P < 0.01), but of statistical difference between group A and B(χ(2) = 6.368, P < 0.01), group A and C (χ(2) = 11.481, P < 0.01). No kyphotic deformity in the group A, no "Close Door" phenomenon in group B and no internal failure in group C. CONCLUSION: The incidence of early axial symptoms are of no significant difference among the three groups, but late axial symptoms are higher in the laminectomy than other groups, which may be associated with loss of cervical lordosis.

Prevalence of vertebral endplate modic changes in degenerative lumbar scoliosis and its associated factors analysis.

STUDY DESIGN: A retrospective study of modic changes (MCs) in degenerative lumbar scoliosis (DLS). OBJECTIVE: To investigate the prevalence of vertebral endplate MCs in DLS and explore their associated factors. SUMMARY OF BACKGROUND DATA: MCs are common in spinal degenerative diseases. Presently, most of the researches have been focused on investigating the relationship between MCs and chronic low back pain. Little has been known on the distribution of MCs in DLS and the relationship between MCs and scoliosis. METHODS: The image data of 120 patients who had been diagnosed with DLS in our hospital from March 2005 to March, 2011 were retrospectively reviewed as the study group. The image data of 89 patients who had been diagnosed with degenerative lumbar diseases without scoliosis were selected as the control group. The prevalence, type, and distribution of MCs in 2 groups were observed and compared. Disc degeneration, Cobb angle, body weight, and smoking were recorded in the study group, and the relationship of MCs with these influential factors was analyzed. RESULTS: Of 1440 endplates from 120 patients in the study group, 247 (17.2%) from 71 (59.2%) patients were found to have MCs. Compared with the control group, of 1068 endplates from 89 patients, 49 (4.5%) endplates from 21 (23.6%) patients were found to have MCs. The prevalence of MCs was significantly higher in the study group than that in the control group (P < 0.01). The MCs in DLS usually had asymmetric distribution with more frequent occurrence on the concave side than on the convex side of major or compensatory curve and mainly occurred at L2-L3, L4-L5, and L5-S1, which were in accordance with the common levels of apex vertebrae. Intervertebral disc degeneration, lumbar scoliosis, overweight and heavy smoking are considered as risk factors to MCs. By multinomial logistic regression analysis on these factors, the regression function was obtained: logit Y = -0.82 + 1.27D + 0.55S + 1.77 D × S (Y for MCs, D for intervertebral disc degeneration, S for scoliosis Cobb's angle and D × S for interaction of D and S). CONCLUSION: The prevalence of MCs in patients with DLS was significantly higher than that of patients without DLS. Most of them were type 2 and usually located on the concave side of apex vertebrae. MCs were significantly associated with intervertebral disc degeneration and lumbar scoliosis.

[Radiological comparison of bilateral paravertebral muscles in degenerative lumbar scoliosis and its potential importance].

OBJECTIVES: To investigate the radiological change of bilateral paravertebral muscles in degenerative lumbar scoliosis (DLS) and analyze its clinical significance. METHODS: As a retrospective study, 66 patients with DLS and 66 patients with lumbar spinal stenosis were retrospectively enrolled from April 2004 to August 2011 as scoliosis group and lumbar spinal stenosis group, meanwhile 66 health persons with no lumbar spinal stenosis were selected as control group. No significant differences were found in the gender, age and body mass index among the three groups. The cross-sectional area (CSA) and percentage of fat infiltration area (FIA) of the bilateral paravertebral muscles at the L(1)-S(1) levels were measured using T2-weighted axial MRI and Image J software. The measured data were analyzed with a paired t-test. RESULTS: In the DLS with bilateral symptom group, the mean percentage of FIA of the multifidus muscle on the convex side were 18% ± 4%, 21% ± 4%, 27% ± 4%, 34% ± 6%, 42% ± 10% and on the concave side were 25% ± 8%, 30% ± 7%, 35% ± 7%, 40% ± 10%, 44% ± 8% at L(1-2), L(2-3), L(3-4), L(4-5) and L(5)-S(1) levels, which showed significant differences between the convex side and the concave side (t = 7.95, 9.30, 5.35, 2.78, 2.38, P < 0.05); the mean percentage of FIA of the longissimus muscle on the convex side were 25% ± 9%, 28% ± 8% and on the concave side were 27% ± 9%, 31% ± 9% at L(3-4), L(4-5) levels, which showed significant differences between the convex side and the concave side (t = 2.52, 3.48, P < 0.05). There were no significant differences in the CSA of both muscles between the concave and convex sides (P > 0.05). In the DLS with unilateral symptom group, the mean percentage of FIA of the multifidus muscle on the convex side were 18% ± 5%, 23% ± 5%, 29% ± 5%, 34% ± 6%, 42% ± 9% and on the concave side were 23% ± 6%, 30% ± 7%, 36% ± 7%, 41% ± 10%, 45% ± 8% at L(1-2), L(2-3), L(3-4), L(4-5) and L(5)-S(1) levels, which showed significant differences between the convex side and the concave side (t = 6.67, 7.96, 6.43, 3.86, 2.15, P < 0.05). There were on significant differences in the CSA of both muscles, and in the percentage of FIA of the longissimus between the concave and convex sides (P > 0.05). CONCLUSIONS: There exist asymmetric degeneration in paravertebral muscle in DLS, which have potential clinical importance on the evaluation of curve progression, and muscle degeneration is more often seen in the concave side. Spinal deformity and radiculopathy may contribute to the paravertebral muscle degeneration.

[Analysis of factors of formation and development about degenerative lumbar scoliosis].

OBJECTIVES: To investigate the correlation between scoliosis angle and the asymmetric index of degenerative lumbar scoliosis, the degree of intervertebral disc degeneration, decreased bone density. METHODS: As a retrospectively study, a total of 96 patients with degenerative lumbar scoliosis were retrospectively enrolled from January 2002 to August 2010 as scoliosis group, meanwhile 96 patients with lumbar spinal stenosis matched in gender, age and body mass index (BMI) were selected as control group. All patients were studied with plain radiographs, MRI and dual energy X-ray absorptiometry at presentation. Radiographic measurements include Cobb angle, the height of the convex and concave side of the apical disc and the contiguous disc superiorly and inferiorly, the height of the convex and concave side of the apical and the contiguous vertebral body superiorly and inferiorly in scoliosis group, the height of L(2-3), L(3-4), L(4-5) discs and the height of L(2-4) vertebral body in control group. The average relative signal intensity of lumbar intervertebral disc and cerebrospinal fluid in T2WI sagittal image was measured in apex intervertebral disc and adjacent discs by Adobe Photoshop 6.0 in scoliosis group, which was measured in L(2-3), L(3-4), L(4-5) disc in control group. The bone density of lumbar, femoral neck, trochanter, and Ward's triangle regions were measured with dual-energy X-ray absorptiometry. RESULTS: The intervertebral disc height in convex side was greater than the height in the concave side [(40 ± 7) mm vs. (28 ± 7) mm, P < 0.01], the vertebral body height in convex side was greater than the height in the concave side [(76 ± 12) mm vs. (72 ± 10) mm, P = 0.016] in scoliosis group. There was significant statistically difference in the degenerative degree of intervertebral discs between two groups (P = 0.003). There was significant statistically difference of the average T-value and the rate of osteoporosis between two groups (P < 0.01). Multiple linear regression analysis showed that the asymmetric disc index, the degenerative degree of intervertebral disc and osteoporosis were the predominant correlative factors, which affected the development of degenerative lumbar scoliosis. CONCLUSIONS: Degenerative lumbar scoliosis is always accompanied by the height asymmetry of intervertebral discs and vertebral body from convex and concavity sides. There is positive correlation between the angle of scoliosis and the asymmetric disc index, the degeneration of intervertebral disc, and negative correlation between the angle of scoliosis and the bone density (T-value).

Intervertebral disc degeneration and bone density in degenerative lumbar scoliosis: a comparative study between patients with degenerative lumbar scoliosis and patients with lumbar stenosis.

BACKGROUND: Degenerative lumbar scoliosis is common in older patients. Decreased bone density and the degeneration of intervertebral discs are considered to be correlated with degenerative lumbar scoliosis. A means of quantifying the relative signal intensity for degenerative disc disease has not been previously discussed. The purpose of this study was to compare bone mineral density and intervertebral disc degeneration between degenerative lumbar scoliosis and lumbar spinal stenosis patients in a nine-year retrospective study. METHODS: From January 2001 to August 2010, 96 patients with degenerative lumbar scoliosis were retrospectively enrolled and 96 patients with lumbar spinal stenosis were selected as controls. Cobb angle, height of the apical disc and the contiguous disc superiorly and inferiorly on convex and concave sides, the height of the convex and concave side of the apical and the contiguous vertebral body superiorly and inferiorly were measured in the scoliosis group. The height of L2/L3, L3/L4, L4/L5 discs and the height of L2/L4 vertebral body was measured in the control group. The grade of intervertebral disc degeneration was evaluated using T2WI sagittal images in both groups. The bone density of lumbar vertebrae was measured with dual-energy X-ray. RESULTS: In scoliosis group, the intervertebral disc height on the convex side was greater than the height on the concave side (P < 0.001). The vertebral body height on the convex side was greater than the height on the concave side (P = 0.016). There was a significant difference between the scoliosis group and the control group (P = 0.003), and between T-value and the rate of osteoporosis between the two groups (both P < 0.001). RESULTS: were verified using multiple linear regression analysis. CONCLUSIONS: Degenerative lumbar scoliosis is accompanied by height asymmetry between the intervertebral disc and vertebral body regarding the convex and concave surfaces. There is a positive correlation between the angle of scoliosis and the disc index, the degree of degeneration of the intervertebral disc, and a negative correlation between the angle of scoliosis and bone density.

[Correlation between intervertebral disc-endplate degeneration and bony structural parameter in adult degenerative scoliosis and its significance].

OBJECTIVES: To analyze the correlation between intervertebral disc-endplate degeneration and bony construction parameter and to explore its roles in adult degenerative scoliosis. METHODS: The imaging data of 79 patients with adult degenerative scoliosis from March 2005 to March 2010 were retrospectively reviewed as the study group. The imaging data of 41 patients with adolescent idiopathic scoliosis were selected as the control group. The vertebral body and intervertebral height in both sides on frontal X-ray, and the facet joint orientation in both sides on CT scan were measured respectively. The average vertebral body height, average intervertebral disc height and average facet orientation were regarded as bony structural parameters. The quantitative grading methods were used in the intervertebral disc and endplate degeneration. The relationship of bony construction parameter and intervertebral disc-endplate degeneration, and the relationship of bony construction parameter and Cobb's angle of scoliosis were analyzed by comparing all bony construction parameters in both groups. RESULTS: Analyzed by paired-t test, the intervertebral height, vertebral body height and facet joint orientation between convex and concave sides of the study group were of significant difference (t = 3.411, 2.623 and 2.085, P < 0.05). The intervertebral height between convex and concave sides of the control group were of significant difference (t = 3.276, P < 0.01), while the vertebral body height and the facet joint orientation were of no statistical significance (t = 1.572 and 1.493, P > 0.05). By linear correlation and regression analysis, the asymmetric degree of bony construction parameter showed good correlation with the score of intervertebral disc-endplate degeneration (-1 < r < 1, P < 0.05), which was positively correlated with Cobb's angle of scoliosis (0 < r < 1, P < 0.05). Linear regression existed between asymmetric degree of bony construction parameter and Cobb's angle (F = 427.342, P < 0.01). The regression function was obtained: Cobb's angle = -8.904+8.136 × IAD + 3.274 × VAD-0.713 × FAD (IAD: intervertebral asymmetry degree, VAD: vertebral asymmetry degree, FAD: facet joint asymmetry degree). CONCLUSIONS: The asymmetric change of bony construction exists in adult degenerative scoliosis, which significantly correlated with intervertebral disc-endplate degeneration and Cobb's angle of scoliosis. The asymmetric bony construction parameter probably plays a biomechanical role in the progression of scoliosis, which maybe the reason for the asymmetric degeneration of intervertebral disc-endplate.