Modic changes in the cervical endplate of patients suffering from cervical spondylotic myelopathy.

BACKGROUND: The distribution and related factors of Modic changes (MC) in the lumbar spine has been evaluated. In the present study, the MC in the cervical endplate of patients with cervical spondylotic myelopathy (CSM) was investigated. METHODS: A total of 6422 cervical endplates of 539 patients suffered from CSM (259 males and 280 females) with mean age of 46 ± 5.2 years. All patients underwent MRI scans and X-ray for evaluating the distribution of MC. The clinical information were recorded. RESULTS: It was observed that 13.0% of patients and 2.4% of endplates showed MC. There were 3.7, 7.6, and 1.7% of cases diagnosed as types I, II, and III, respectively, suggesting MC were corrected with disc degeneration. The incidence rates of MC were 0, 0.3, 0.6, 0.9, 0.7, and 0.2%, respectively, in different intervertebral disc segments C2-3, C3-4, C4-5, C5-6, C6-7, and C7T1. Disc degeneration, segment, disease course, and age were statistically related to the MC. Patients over the age of 40 more easily suffered from MC. CONCLUSIONS: MCs manifested as type II mainly in patients with CSM. The incidence was highest in the C5-6 segment. Disc degeneration greatly contributed to the occurrence of MC.

Treatment of cerebrospinal fluid leak after spine surgery.

Owing to the complexity of spinal surgery, there is a great prevalence of dural tear causing cerebrospinal fluid (CSF) leakage. Many studies focused on suture repair for dural tear to stop CSF leak. Now some new treatment strategies have shown a promising effect that is listed as follows: 1) creating watertight dural closure to stop CSF leak with the help of dural substitute material; and 2) retarding CSF leak by changing pressure difference, including reducing the subarachnoid fluid pressure, increasing the epidural space pressure and both. In fact several methods mentioned above are usually combined to treat CSF leak. However, no update review summarized the relevant studies implemented in recent years. In this review, the authors would compare the effects of different dural closure techniques, and introduce the latest treatment methods and mechanisms.

[Etiology and treatment of postoperative spinal cord injury for patients undergoing laminectomy for fluorosis thoracic canal stenosis].

OBJECTIVE: To elucidate the etiology of postoperative spinal cord injury (PSCI) for patients undergoing laminectomy for fluorosis thoracic canal stenosis (FTCS) and summarize the methods of diagnosis and treatment. METHODS: From 2006 to 2009, a total of 192 FTCS cases underwent laminectomy. Among them, 16 cases with gradual postoperative neural deterioration were finally diagnosed as PSCI on MRI.One case of intraoperative spinal cord injury was excluded so that only 15 cases were included. RESULTS: All cases were treated immediately with incision cite puncture and dehydration.Neural function recovered after secondary operation as JOA score improved from 3.00 ± 1.14 to 7.72 ± 1.41 at 12 months follow-up.Statistical analysis demonstrated a linear correlation between the diagnosis time and the improvement of JOA score. CONCLUSION: Hematoma and fluid leakage are the common reasons of PSCI for FTCS patients. Meticulous hemostasis, usage of artificial dura matter and partial negative pressure drainage are valuable preventive measures.

[Damage of blood brain barrier of spinal cord in rats with chronic fluorosis].

OBJECTIVE: To explore the impairment mechanisms of blood brain barrier in spinal cord and observe the changes of matrix metalloproteinase-9 (MMP-9) and functional improvement in rats with chronic fluorosis. METHODS: A total of 120 Wistar rats were divided randomly into 4 groups, high fluoride (fed by water with a high concentration of sodium fluoride at 200 mg/L), high fluoride control (fed by distilled water), defluorination (fed by water with a high concentration of sodium fluoride at 200 mg/L for 12 weeks and then distilled water for 12 weeks) and defluorination control (n = 30 each). The urinary contents of fluoride were detect for 4 groups at Weeks 4, 8 and 12. The high fluoride and control groups were sacrificed at Week 12 while the defluorination and defluorination control groups at Week 24. Their cervical spinal cords were collected for electron microscope examinations. The expression of MMP-9 protein in thoracic cord was detected by immunohistochemistry and Western blot. Quantitative analysis of function of blood brain cord barrier was performed by the technique of Evans blue. The comparison of measurement data was performed with F test and correlation analysis. The cytological changes of neurons in thoracic spinal cord were detected after chronic fluorosis. RESULTS: Under electron microscope, the pathological manifestations of chronic damage in blood brain barrier could be found. As compared with the high fluoride control group, the content of Evans blue increased markedly in spinal cord of the high fluoride group (29.2 ± 0.1 vs 0.7 ± 0.1 mg/L, P < 0.01). It was higher in the defluorination group than that in the defluorination control group. But there was no significant difference with the high fluoride group (29.2 ± 0.1 vs 28.9 ± 0.2 mg/L, P > 0.01). And the expression of MMP-9 increased in spinal cord of the fluorosis and defluorination groups in comparison with those in the control group. But no difference existed among them. CONCLUSION: The damage of blood brain barrier of spinal cord occurs probably as a result of a higher expression of MMP-9 in rats with chronic fluorosis. Defluorination for a short time may not recover.

Influence of hinge position on the effectiveness of open-door expansive laminoplasty for cervical spondylotic myelopathy.

OBJECTIVE: To assess the influence of different hinge positions on clinical results of expansive open-door laminoplasty (EOLP) for cervical spondylotic myelopathy (CSM). METHODS: A total of 102 CSM patients who underwent EOLP from February 2006 to February 2007 were enrolled in this randomized controlled trial. Using a random digits table, 57 patients with the hinge located at the inner margin of the lateral mass were classified as wide-open group, while 45 patients with the hinge positioned at the lamina margin served as narrow-open group. All patients were observed over 24 months, and the clinical and radiological results were analyzed statistically. RESULTS: There were no significant differences in operation duration, intraoperative bleeding volume, Japanese Orthopaedic Association (JOA) scores, cervical curvature index, range of motion and neural function recovery rate. The neural functions were satisfactorily improved after surgery in both groups, while the severity of axial symptoms was significantly lower in the narrow-open group than in the wide-open group (P equal to 0.003). The incidence of C(5) palsy in the wide-open group was higher than that in the narrow-open group (5.3% vs 0), even though the difference did not reach statistical significance (one tailed Fisher's exact test, P equal to 0.17). CONCLUSIONS: Proper inward shift of the hinge can ensure effectiveness of surgical decompression, avoid an excessive backward shift of the spinal cord, decrease the incidence of C(5) palsy and alleviate the severity of axial symptoms.

[Relationship between expression of MMP-9 and presyrinx state of experimental syringomyelia of rabbits].

OBJECTIVE: To investigate the relationship between the expression of MMP-9 and the formation of spinal cord edema in presyrinx state of experimental syringomyelia in rabbits and evaluate the inhibitory function of doxycycline in the formation of spinal cord edema in presyrinx state. METHODS: A total of 96 Chinese white rabbits were divided randomly into four groups:kaolin group (n = 24), doxycycline treatment group (n = 24), physiological saline group (n = 24) and control group (n = 24). Under ketamine anesthesia, 0.6 ml of 25% kaolin solution was injected into the cisterna magna in all rabbits of kaolin and doxycycline groups while 0.6 ml of 37°C physiological saline into the cistern in those of saline group; doxycycline (25 mg × kg(-1) × d(-1)) was applied post-operatively for doxycycline group. At Days 1, 3, 7 and 14 after kaolin injection, 6 rabbits of all four groups were selected randomly for sacrificing. Water content of spinal cord could be obtained. The expression of MMP-9 activity was measured by Western blot and immunohistochemistry. RESULTS: At any time point, the water content of spinal cord and the expression of MMP-9 in kaolin group improved obviously more than those of saline and control groups (P < 0.01). At Day 1, there was no marked difference in the water content of spinal cord and the expression of MMP-9 between doxycycline and kaolin groups (P > 0.05). At other time points, the water content of spinal cord and the expression of MMP-9 in doxycycline group markedly decreased than those of kaolin group (P < 0.01). CONCLUSION: In the model of experimental syringomyelia, MMP-9 plays an important role in causing edema in presyrinx state. Thus doxycycline may be used to prevent and treat syringomyelia.

Radiographic predictors of residual low back pain after laminectomy for lumbar canal stenosis: a minimum of 6-year follow-up.

OBJECTIVE: To identify radiographic predictors of residual low back pain (LBP) after laminectomy for lumbar canal stenosis (LCS). METHODS: Clinical results and radiographic findings in 69 patients who underwent single level laminectomy for LCS were retrospectively reviewed. Patients who had an improvement in LBP scores evaluated by Japanese Orthopaedic Association (JOA) scoring system during the follow-up periods were classified as the recovery group, and others were classified as the non-recovery group. Patients'clinical data and radiographic parameters like lordosis angle, range of motion and intervertebral rotational angle were analyzed using binary logistic regression analysis to detect factors significantly related with the occurrence of residual LBP. RESULTS: The average preoperative JOA score of 14.8+/-5.05 improved to 21.59+/-5.51 at the final follow-up. Binary logistic regression analysis revealed that significant predictors of residual LBP were preoperative lumbar lordosis angle and range of motion. CONCLUSIONS: Our results suggest that patients with flat back and limited lumbar mobility before surgery tend to have poor results in terms of LBP. Therefore, these sagittal radiographic parameters should be taken into account when choosing laminectomy as the surgical option for LCS.