[Three-dimensional finite element analysis of lumbar disc herniation under different body positions].

OBJECTIVE: To campare biomechanical effects of different postural compression techniques on three-dimensional model of lumbar disc herniation (LDH) by finite element analysis. METHODS: Lumbar CT image of a 48-year-old female patient with LDH (heighted 163 cm, weighted 53 kg) was collected. Mimics 20.0, Geomagic Studio, Solidwords and other software were used to establish three-dimensional finite element model of LDH on L4,5 segments. Compression techniques under horizontal position, 30° forward bending and 10° backward extension were simulated respectively. After applying the pressure, the effects of compression techniques under different positions on stress, strain and displacement of various tissues of intervertebral disc and nerve root were observed. RESULTS: L4, 5 segment finite element model was successfully established, and the model was validated. When compression manipulation was performed on the horizontal position, 30° flexion and 10° extension, the annular stress were 0.732, 5.929, 1.286 MPa, the nucleus pulposus stress were 0.190, 1.527, 0.295 MPa, and the annular strain were 0.097, 0.922 and 0.424, the strain sizes of nucleus pulposus were 0.153, 1.222 and 0.282, respectively. The overall displacement distance of intervertebral disc on Y direction were -3.707, -18.990, -4.171 mm, and displacement distance of nerve root on Y direction were +7.836, +5.341, +3.859 mm, respectively. The relative displacement distances of nerve root and intervertebral disc on Y direction were 11.543, 24.331 and 8.030 mm, respectively. CONCLUSION: Compression manipulation could make herniated intervertebral disc produce contraction and retraction trend, by increasing the distance between herniated intervertebral disc and nerve root, to reduce symptoms of nerve compression, to achieve purpose of treatment for patients with LDH, in which the compression manipulation is more effective when the forward flexion is 30°.

Solitary Fibrous Tumor of Central Nervous System: Clinical and Prognostic Study of 24 Cases.

BACKGROUND: Solitary fibrous tumors (SFTs) are rare mesenchymal tumors that occasionally occur in the central nervous system (CNS). It is difficult to fully understand their clinical characteristics, partly due to a limited number of reported cases. METHODS: We reviewed 24 patients admitted to our institution between 2009 and 2016 with CNS solitary fibrous tumors. We reviewed and analyzed patient profiles, such as demographics, presentations, imaging studies, extent of resection, and adjuvant treatment. Differences between malignant and benign SFTs were assessed using the χ2 test or Student's t-test. Kaplan-Meier analysis was used to estimate the disease-free survival (DFS) rate. The multivariate Cox regression analysis was performed to evaluate the possible predictive value of the DFS rate of the previously mentioned covariates. RESULTS: A total of 13 men and 11 women were enrolled in the study (the average age was 43). The median follow-up time was 58 months. Twenty-one patients underwent gross total resection (GTR), and 3 patients received a subtotal resection (STR). The tumors in 15 patients (62.5%) were atypical or malignant. One patient (4.2%) suffered SFT-related death (multiple organ failure by tumor metastasis), and 3 patients (12.5%) experienced tumor recurrence. We found that a large tumor size (≥10 cm, P < 0.001) and STR (P < 0.001) were negatively associated with the DFS rate. CONCLUSION: CNS SFTs are rare, slow-growing, less aggressive, and recrudescent tumors. Complete resection is the most effective therapy. Large tumor size and STRs might shorten DFS time.

Influence of acylpeptide hydrolase polymorphisms on valproic acid level in Chinese epilepsy patients.

BACKGROUND: Concomitant use of meropenem (MEPM) can dramatically decrease valproic acid (VPA) plasma level. It is accepted that inhibition in acylpeptide hydrolase (APEH) activity by MEPM coadministration was the trigger of this drug-drug interaction. AIM: To investigate the influence of APEH genetic polymorphisms on VPA plasma concentration in Chinese epilepsy patients. PATIENTS & METHODS: Urinary VPA-d6 ß-D-glucuronide concentration was determined in 19 patients with VPA treatment alone (n = 10) or concomitant use with MEPM (n = 9). A retrospective study was performed on 149 epilepsy patients to investigate the influence of APEH polymorphisms rs3816877 and rs1131095 on adjusted plasma VPA concentration (CVPA) at steady-state. RESULTS: Urinary VPA-d6 ß-D-glucuronide (VPA-G) concentration was increased significantly in patients with MEPM coadministration. The CVPA of patients carrying the APEH rs3816877 C/C genotype was significantly higher than that of C/T carriers, and the difference was still obvious when stratified by UGT2B7 rs7668258 polymorphism. CONCLUSION: APEH polymorphism has significant influence on VPA pharmacokinetics in Chinese population.