Wen-Yuan Ding

Magnetic resonance T2 image signal intensity ratio and clinical manifestation predict prognosis after surgical intervention for cervical spondylotic myelopathy.

Study Design. A retrospective imaging study of 73 patients who underwent surgery for cervical spondylotic myelopathy (CSM) between April 2005 and July 2007. Objective. To investigate whether magnetic resonance (MR) T2 image signal intensity (SI) ratio and clinical manifestation can assess the prognosis in patients with CSM. Summary of Background Data. The association between intramedullary high SI on T2-weighted MR images and surgical outcome in CSM remains controversial. The means of quantizing SI ratio for the disease has not been discussed. Methods. A total of 73 patients with cervical compressive myelopathy were retrospectively enrolled and were treated with anterior, posterior, and posterior-anterior united decompression. A total of 1.5-T magnetic resonance imaging was performed in all patients before surgery. T2-weighted images of sagittal increased SI on the cervical spinal cord were obtained, and the regions of interest (ROIs) are taken by 0.05 cm2. T2-weighted MR images of sagittal normal cord SI on the cervical between C7-T1 disc levels were obtained, and the ROIs are taken by 0.3 cm2. SI value is measured by computer, and the SI ratio between the regions 0.05 cm2 and 0.3 cm2 has been calculated. If no intramedullary high SI was noted on T2-weighted MR images, the ROIs were taken by 0.05 cm2 of the severe compression cord. All patients had been divided into 3 groups by hierarchical clustering analysis with SI ratio (Group 1: low SI ratio, Group 2: middle SI ratio, and Group 3: high SI ratio). Statistical analyses were performed with SPSS 11.0. Results. There are significant differences between 3 groups by comparing the recovery rate (P < 0.001), age (P = 0.003), duration of disease (P = 0.001), Babinski sign (P < 0.001), preoperative JOA score (P = 0.006), and postoperative JOA score (P < 0.001). There are no significant differences on sex among 3 groups (P = 0.387). By using the multiple comparison analysis, the above results are further shown. Conclusion. Patients with low SI ratio who were not too old and had a shorter duration of disease experienced a good surgical outcome. However, with the increase of SI ratio and the occurrence of pyramidal sign, a poor prognosis after surgery will show. SI ratio and clinical manifestation can be a predictor of surgical outcome.

Correlative factor analysis on the complications resulting from cement leakage after percutaneous kyphoplasty in the treatment of osteoporotic vertebral compression fracture.

Study Design The correlative factors for complications resulting from cement leakage were retrospectively reviewed in 71 patients who underwent percutaneous kyphoplasty. Objective To explore the correlative factors affecting the complications of percutaneous kyphoplasty in the treatment of osteoporotic vertebral compression fractures. Summary of Background Data Over the past decade, percutaneous kyphoplasty has been increasingly used as treatment of choice for osteoporotic vertebral compression fractures. However, current literature contains less information about the correlative factors affecting the complications resulted from cement leakage. Methods In all, 71 patients with 171 vertebral compression fractures who were treated by percutaneous kyphoplasty in the department of spine surgery at our medical center were identified from the registry and were retrospectively reviewed. The treatment efficacy was determined by the assessment of change in vertebral body height, Cobb angle, visual analog scale and Oswestry functional score between preoperative, postoperative, and the latest follow-up. Complications were recorded and associated risk factors were determined and analyzed. Results All patients had immediate and significant improvement in back pain after being treated with percutaneous kyphoplasty. Cement leakage occurred in 17 (9.94%) out of 171 vertebral bodies, including 7 paravertebral leaks, 6 leaks into intervertebral space, 3 leaks into channel of needling insertion, and 1 spinal canal leak. Four patients (5.63%) developed pulmonary complications postoperatively, one of them with confirmed diagnosis of pulmonary embolism directly caused by cement leakage. During the follow-up, we found 9 recurrence vertebral fractures in 6 patients (8.45%), including 6 adjacent vertebral bodies. Univariate analysis revealed a significant difference in preoperative vertebral body height, injected cement volume, and vertebral body wall incompetence between the cement leakage group and no cement leakage group (P<0.05). In contrast, there is no significant difference in the preoperative Cobb angle, freshness of vertebral fracture, location of operative vertebrae, and operative approach between the 2 groups (P>0.05). Multiple logistic regression analysis showed that the injected cement volume and vertebral body wall incompetence were the predominant variables associated with the complications resulting from cement leakage. The patients who had a history of pulmonary diseases were prone to develop lung-related complications after the surgery. Conclusions The cement viscosity, injected cement volume, vertebral body wall incompetence, and a history of pulmonary diseases were the factors affecting the complications resulting from cement leakage. The recognition of these risk factors is helpful in efforts to improve surgical technique to reduce the risk of complications after being treated by percutaneous kyphoplasty.

Using the T2-weighted magnetic resonance imaging signal intensity ratio and clinical manifestations to assess the prognosis of patients with cervical ossification of the posterior longitudinal ligament

OBJECT The aim of this study was to investigate the clinical significance of both the signal intensity ratio obtained from MR imaging and clinical manifestations on the prognosis of patients with cervical ossification of the posterior longitudinal ligament. METHODS The authors retrospectively reviewed the records of 58 patients with cervical ossification of the posterior longitudinal ligament who underwent cervical laminoplasty from February 1999 to July 2007. Magnetic resonance imaging (1.5-T) was performed in all patients before surgery. Sagittal T2-weighted images of the cervical spinal cord compressed by the ossified posterior longitudinal ligament showed increased intramedullary signal intensity, whereas the sagittal images obtained at the C7-T1 disc levels were of normal intensity. The signal intensity ratio between regions of intramedullary increased signal intensity and the normal C7-T1 disc level was calculated based on the signal intensity values generated from the MR imaging workstation. Patients were divided into 3 groups according to their signal intensity ratio (high, intermediate, and low signal intensity groups). RESULTS There were significant differences between the 3 groups regarding recovery rate (p < 0.001), age (p = 0.022), duration of disease (p = 0.001), Babinski sign (p < 0.001), ankle clonus (p < 0.001), and both pre- and postoperative Japanese Orthopaedic Association score (p < 0.001). There was no significant difference in sex among the 3 groups (p = 0.391). CONCLUSIONS Patients with low signal intensity ratios that changed on T2-weighted imaging experienced a good surgical outcome. Low increased signal intensity might reflect mild neuropathological alteration in the spinal cord and greater recuperative potential. An increased signal intensity ratio with positive pyramidal signs indicates less recuperative potential of the spinal cord and a poor surgical outcome.

Significance of increased signal intensity on MRI in prognosis after surgical intervention for cervical spondylotic myelopathy

We aimed to examine whether increased signal intensity (ISI) on T2-weighted MRI can be used to predict the surgical outcome of patients with cervical spondylotic myelopathy (CSM). ISI on T2-weighted MRI are frequently observed but the relevance of this finding remains controversial in patients with CSM. Between September 2007 and February 2009, 52 patients with CSM who underwent surgery were studied prospectively. Preoperative and postoperative functional status was evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system, and the recovery rate was calculated using the Hirabayashi method. An MRI was performed on all patients. For those with ISI on T2-weighted MRI, the ratio of the signal intensity on T2-weighted to T1-weighted MRI (T2:T1 ratio) at the same spinal cord level and of similar area was calculated. Although the clinical outcome of all patients had improved at final follow-up, there was a significant difference between patients with ISI and those without ISI in age, duration of symptoms, preoperative and postoperative JOA scores, and recovery rate. The preoperative and postoperative JOA scores and the recovery rate differed significantly (p<0.05) between the three groups: patients without a T2-weighted ISI, and those with different levels of a T2:T1 ratio. Patients with an ISI usually had a low preoperative JOA score and experienced less improvement in neurologic function after surgery. The T2:T1 ratio can be used to help predict surgical outcomes.

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 Cobbs 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.

Effect of Modified Techniques in Bryan Cervical Disc Arthroplasty

Study Design. A prospective, randomized study of the clinical and radiographic outcomes in patients undergoing single- and 2-level cervical arthroplasty with Bryan cervical disc (Medtronic Sofamor Danek, Memphis, TN). Objective. This study was designed to investigate the modified techniques of cervical arthroplasty with Bryan disc and analyze the clinical and radiologic effects. Summary of Background Data. Aggravation of kyphosis is the known challenge after arthroplasty. Disc insertion angle and overmilling were reported to be factors causing kyphosis. However, few studies have performed methods to avoid these factors. Additionally, translation and length matching of prosthesis seemed to be ignored. There have been no studies regarding the effects of modified techniques for the prevention of these adverse outcomes. Methods. Modified techniques include change in disc insertion, reducing overmilling of endplates, the assurance of the anterior borders at the same horizontal line, and the accurate fitness of prosthesis size. Techniques described in product monograph were applied to 20 patients (control group) and modified techniques were applied to 19 patients (investigational group). Clinical and radiologic (radiograph) follow-ups of all the patients were performed before surgery and after surgery (6 months). Comparisons between the 2 groups in terms of functional spinal unit angle, shell angle, the anteroposterior displacement between the 2 metal shells in the neutral position, and the fitness of prosthesis size were performed. Results. Radiologic outcomes in investigational group were significantly superior to those in control group; clinical outcomes were similar in both groups. Conclusion. The modified techniques can improve the outcomes of the cervical arthroplasty with Bryan disc and prevent the unexpected imbalance and motion of cervical spine.

Enlarged laminectomy and lateral mass screw fixation for multilevel cervical degenerative myelopathy associated with kyphosis.

BACKGROUND CONTEXT Either an anterior approach or a posterior approach, which aims to decompress the spinal cord and restore the sagittal alignment, has been adopted to treat multilevel cervical degenerative myelopathy (CDM) associated with kyphosis. However, there is controversy on the optimal surgical strategy for the treatment of multilevel CDM with kyphotic deformity because of the complications of each surgical approach. PURPOSE The purpose of this study was to investigate the surgical efficacy of enlarged laminectomy (removing the inside edge of facet joints and decompressing the nerve foramina) and lateral mass screw fixation for the treatment of multilevel CDM associated with kyphosis. STUDY DESIGN A retrospective radiographic and clinical study to access the efficacy of enlarged laminectomy with lateral mass screw fixation in the treatment of multilevel CDM related to kyphosis. PATIENT SAMPLE A total of 43 patients (28 men and 15 women; average age, 59.6 years) with multilevel CDM correlated to kyphosis were obtained in the study. OUTCOME MEASURES All radiological data were recorded on computer-based measurement from preoperative or postoperative X-ray, magnetic resonance imaging (MRI), and computed tomography. All neurological parameters were accessed in each patient. METHODS Analysis consisted of: Japanese Orthopedic Association (JOA) score, recovery rate, curvature index (CI), the expansion degree and drift-back distance of the spinal cord, axial symptom severity, and C5 root palsy. The recovery rate based on the JOA score was calculated for each patient. Cervical CI as well as the expansion degree and drift-back distance of the spinal cord was measured using MRI. Axial symptom severity was quantified by a visual analog scale (VAS). Statistical analysis was performed using paired t test with significance set at p<.05. RESULTS Enlarged laminectomy was performed over a mean of 3.97 levels (range, 3-5 levels). Follow-up information was obtained at a mean of 2.8 years (range, 1.5-5 years) after surgery. Analysis of the final follow-up data showed significant differences before and after surgery in the JOA score (t=24.17, p<.001), CI improvement (t=21.89, p<.001), the anteroposterior diameter at the level of maximum compression of the spinal cord (t=9.54, p<.001), and VAS score (t=13.30, p<.001). The mean spinal cord posterior shift was 4.72±1.10 mm (range, 0-6.71 mm). X-rays confirmed that bone grafts were completely fused at a mean of 3 months after surgery. During the follow-up period, only two patients (4.7%) did not obtain complete recovery, four patients (9.3%) experienced axial symptoms; there were no C5 root palsy and instrument failures noted in this series. CONCLUSION Enlarged laminectomy with fixation for the management of multilevel CDM is demonstrated to be an effective strategy for improving neurological function, restoring the normal cervical lordosis, and decreasing the incidence of axial symptoms and C5 root palsy, but there is a need for randomized controlled studies with long-term follow-up to confirm and clarify these results.

17β-Estradiol protects against apoptosis induced by levofloxacin in rat nucleus pulposus cells by upregulating integrin α2β1

Levofloxacin has been reported to have cytotoxicity to chondrocytes in vitro. And 17β-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 17β-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 17β-estradiol. Interestingly, estrogen receptor antagonist, ICI182780, and functional blocking antibody to α2β1 integrin, both prohibited the effect of 17β-estradiol. Simultaneously, levofloxacin decreased cellular binding ability to type II collagen, which was also reversed by 17β-estradiol. Furthermore, western blot and real-time quantitative PCR were used to find that integrin α2β1 was responsible for estrogen-dependent anti-apoptosis, which was time–response and dose–response effect. 17β-estradiol was proved for the first time to protect rat nucleus pulposus cells against levofloxacin-induced apoptosis by upregulating integrin α2β1 signal pathway.

Risk factors for periprosthetic joint infection following primary total hip or knee arthroplasty: a meta-analysis

To identify risk factors for periprosthetic joint infection following primary total joint arthroplasty, a systematic search was performed in Pubmed, Embase and Cochrane library databases. Pooled odds ratios (ORs) or standardised mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. Patient characteristics, surgical‐related factors and comorbidities, as potential risk factors, were investigated. The main factors associated with infection after total joint arthroplasty (TJA) were male gender (OR, 1·48; 95% CI, 1.19–1.85), age (SMD, −0·10; 95% CI, −0.17–−0.03), obesity (OR, 1·54; 95% CI, 1·25–1·90), alcohol abuse (OR, 1·88; 95% CI, 1·32–2·68), American Society of Anesthesiologists (ASA) scale > 2 (OR, 2·06; 95% CI, 1·77–2·39), operative time (SMD, 0·49; 95% CI, 0·19–0·78), drain usage (OR, 0·36; 95% CI, 0·18–0·74), diabetes mellitus (OR, 1·58; 95% CI, 1·37–1·81), urinary tract infection (OR, 1·53; 95% CI, 1.09–2.16) and rheumatoid arthritis (OR, 1·57; 95% CI, 1·30–1·88). Among these risk factors, ASA score > 2 was a high risk factor, and drain usage was a protective factor. There was positive evidence for some factors that could be used to prevent the onset of infection after TJA.

Combined effect of 17β-estradiol and resveratrol against apoptosis induced by interleukin-1β in rat nucleus pulposus cells via PI3K/Akt/caspase-3 pathway

Background: In previous studies, both 17β-estradiol (E2) and resveratrol (RES) were reported to protect intervertebral disc cells against aberrant apoptosis. Given that E2 has a better anti-apoptotic effect with more cancer risk and RES has an anti-apoptotic effect with less cancer risk, the combined use of E2 with RES is promising in developing clinical therapies to treat apoptosis-related diseases such as intervertebral disc degeneration in the future. Objective: The purpose of this study was to explore the combined effect of E2 with RES on rat nucleus pulposus cells and the underlying mechanisms. Methods: TUNEL assay and FACS analysis were used to determine apoptotic incidence of nucleus pulposus cells. MTS assay was used to determine cell viability, and cellular binding assay was used to determine cell-ECM (extracellular matrix) ability. Real-time quantitative RT-PCR was to determine mRNA level of target genes. And Western blot was used to determine the protein level. Results: Both E2 and RES decreased apoptotic incidence when used singly; interestingly, they decreased apoptosis more efficiently when used combinedly. Meanwhile, E2 and RES combined together against the decrease of cell viability and binding ability resulting from IL-1β cytotoxicity. As well, activated caspase-3 was suppressed by the combined effect. Furthermore, IL-1β downregulated expression level of type II collagen and aggrecan (standing for anabolism), while upregulated MMP-3 and MMP-13 (standing for catabolism). However, the combined use of E2 with RES effectively abolished the above negative effects caused by IL-1β, better than either single use. Finally, it turned out to be that E2 and RES combined together against apoptosis via the activation of PI3K/Akt/caspase-3 pathway. Conclusion: This study presented that IL-1β induced aberrant apoptosis, which was efficiently resisted by the combined use of E2 with RES via PI3K/Akt/caspase-3 pathway.