Biomedical subjects

Xi-sheng Weng

Publications and source records attributed to Xi-sheng Weng.

25 records · Page 2Linked to original sources

PubMed2004

[Short-term results of modular extensively porous-coated revision stem in revision total hip arthroplasty].

OBJECTIVE: To evaluate the short-term clinical and radiographic results of modular fully porous-coated stem in revision operation of total hip arthroplasty. METHODS: From May 2001 to November 2002, ten cases with twelve hips received revision total hip arthroplasty using modular Profemur R with fully porous-coated stem. There were three males and seven females and the average age was 54.2 years (35 to approximately 71 years). The reasons for revision operation included aseptic loosing in eleven hips and septic loosing in one hip. All the patients were evaluated radiographically and clinically. Radiographic evaluation included the classification of bone loss, leg discrepancy, offset and antiversion before and after revision and bone in-growth postoperatively. Clinical evaluation were based on Harris score system. RESULTS: The average follow-up period is 13.5 months (range: 6 to approximately 24 months). Leg discrepancy from more than 2 cm in six cases were restored to less than 1 cm postoperatively. Femoral offset, antiversion angle and neck-shaft angle were also restored to normal limitation. All the patients were allowed to full weight-bearing 3 to approximately 5 months later and pain relief occurred in all involved hips. At the last follow-up, bone in-growth occurred in eleven hips and solid fibrous fixation only in one case. Harris score was improved from a mean of 25 to 72. Complications mainly consisted of femoral shaft fracture in three cases but no infection or dislocation was found postoperatively. CONCLUSIONS: Satisfactory results of short-term radiographic and clinical follow-up can be achieved using modular fully porous-coated stem for revision total hip arthroplasty.

Adult↗

PubMed2004

Posterior selective thoracic fusion in adolescent idiopathic scoliosis.

OBJECTIVE: To define the criteria of posterior selective thoracic fusion in patients with adolescent idiopathic scoliosis. METHODS: By reviewing the medical records and roentgenograms of 17 patients with adolescent idiopathic scoliosis who underwent posterior selective thoracic fusion, the curve type, Cobb angle, apical vertebral rotation and translation, trunk shift, and thoracolumbar kyphosis were measured and analyzed. RESULTS: There were 17 King type II patients (PUMC type: IIb, 13, IIc3 4). The coronal Cobb angle of thoracic curve before and after operation were 56.9 degrees and 21.6 degrees respectively, the mean correction rate was 60.1%. The coronal Cobb angle of lumbar curve before and after operation were 34.8 degrees and 12.1 degrees respectively, and the mean spontaneous correction rate was 64.8%. At final follow-up, the coronal Cobb angle of thoracic and lumbar curve were 23.5 degrees and 15.2 degrees respectively, there were no significant changes in the coronal Cobb angle, apical vertebral translation and rotation compared with that after operation. One patient had 12 degrees of thoracolumbar kyphosis after operation, no progression was noted at final follow-up. There was no trunk decompensation or deterioration of the lumbar curve. In this group, 3.9 levels were saved compared with fusing both the thoracic and lumbar curves. CONCLUSION: Posterior selective thoracic fusion can be safely and effectively performed in King type II patients with a moderate and flexible lumbar curve, which can save more mobile segments and at the same time can maintain a good coronal and sagittal balance.

Adolescent↗

PubMed2004

[Effect of combined continued hormone replacement therapy on knee osteoarthritis symptom of postmenopausal women].

OBJECTIVE: To study the effect of combined continued estrogen and progestin replacement therapy on knee osteoarthritis (OA) symptoms of postmenopausal women. METHODS: Sixty-four postmenopausal women with radiological knee OA and symptoms aged 45-75 were divided into treatment group and control group. They were given estradiol velerate (E2V) 1.0 mg/d and medroxyprogestetone acetate (MPA) 2 mg/d (treatment group) or placebo (control group) for 6 months. Calcium 400 mg/d were given to all cases. Then 0-100 mm visual analon scale (VAS) was used to evaluate the severity of knee pain at baseline and after 1, 3, 6 month of treatment. RESULTS: Significant differences on pain at night and tenderness around knee were seen in the treatment group compared with the control group after 1 months of treatment (P = 0.036 and 0.035, respectively). The improvement of pain at night, during walk and morning stiffness between the two groups showed significant difference after 6 months (P = 0.026, 0.027, and 0.011, respectively). CONCLUSION: Combined estrogen and progestin replacement therapy can relieve the knee OA symptoms of postmenopausal women.

Aged↗

PubMed2003

[Design and preliminary clinical application of general spine system].

OBJECTIVE: To evaluate the efficacy of self-designed General Spine System (GSS) through the measurement of the biomechanical characteristics and the outcomes of preliminary clinical application. METHODS: The General Spine System implants were made of titanium alloy (TC4, Ti6Al4V) and the instruments were made of stainless steel after design. Pull-out strength of GSS screw, CCD, SOCON, TSRH and Diapason screw were tested in fresh normal cadaveric spine specimens respecting and the biomechanical stability analyses of GSS and SOCON were also tested. GSS was applied clinically in 16 patients with degenerative lumbar spondylolisthesis combined with lumbar canal stenosis. Clinical efficacy, reduction effectiveness, and complications were recorded. RESULTS: The pull-out strength of GSS screw was more than other control screws. Biomechanical stability of GSS was similar to SOCON system. Average postoperative follow-up for all patients was 12.6 months (11.5-14.5 months). All patients got satisfied clinical results at the latest follow-up. X-ray results showed complete reduction for all spondylolisthesis patients, and results remained good in follow-up. Complications related to implants or operation were not observed after surgery or in follow-up. CONCLUSION: GSS pedicle screws have strong anchoring ability and good stabilization for spondylolisthesis. This system can provide good reduction for spondylolisthesis. Its clinical efficacy is confirmed.

Adult↗

PubMed2003

[The effect of estrogen and progestin on the expression of matrix metalloproteinases, tissue inhibitor of metalloproteinase and interleukin-1beta mRNA in synovia of OA rabbit model].

OBJECTIVE: To observe the effect of different dose of estrogen or estrogen plus progestin on the mRNA expression of MMP-1, MMP-3, TIMP-1 and IL-1beta in synovia of female New Zealand White rabbit OA model. METHODS: Sixty-five female New Zealand White rabbits (3 kg +/-, 6 months old) were used in this study. Right knees of all the rabbits were immobilized for 5 weeks to get OA model. Then 5 rabbits were killed by overdose of anesthesia to guarantee the model. Sixty OA rabbits were randomly divided into 6 groups (A, B, C, D, E, F) with 10 each. Group A approximately E were ovariectomized and group F were sham ovariectomized. The rabbits were feed by estradiol valerate (E(2)V) everyday as follows. Group A: E(2)V 1.8 mg/d, group B: E(2)V 3.6 mg/d, group C: E(2)V 7.2 mg/d, group D: E(2)V 3.6 mg/d + MPA 3.6 mg/d, group E was the untreated control group, group F was the untreated sham control group. Five rabbits of each group were killed respectively in 8 and 16 weeks and synovia of the right knee were obtained on all knees. Reverse transcription- polymerase chain reaction were used to detect the mRNA expression of MMP-1, MMP-3, TIMP-1 and IL-1beta in the OA synovia to determine the effect of estrogen and progestin. RESULTS: RT-PCR shows an increase expression of mRNA of MMP-1, MMP-3 and IL-1beta in OA synovia tissue in ovariectomized rabbits. Estrogen supplement could decrease the expression, an enhancement effect could be observed with progestin. Low dose estrogen could decrease the ratio of MMP-1/TIMP-1 and MMP-3/TIMP-1, which could even be decreased by progestin. High dose estrogen could slightly increase the ratio, but still lower than the untreatment control group. CONCLUSION: Our study suggests that certain dose estrogen and perhaps appropriate estrogen and progestin ratio are much important to the normal effect of articular cartilage. Estrogen deficiency or much high estrogen level could both show a damage effect on articular cartilage.

Animals↗

PubMed2003

[Biomechanical evaluation of the stability of General spine system].

OBJECTIVE: To evaluate the biomechanical stability of Shen's instrumentation in the management of thoracolumbar fractures. METHODS: The ranges of movement (ROM) in three dimensions of twelve T(12) - S(3) specimen of fresh adult cadavers were measured sequentially in the states of normal, injured, GSS and SOCON fixation, fatigued GSS and SOCON fixation. Data were then compared. RESULTS: For the L(2 - 3) segment, the average normal ROM in flexion was 8.3 degrees. In the established spondylolisthesis models, the ROM was 14.7 degrees. After fixation with SOCON, the ROM was decreased to 3.0 degrees, indicating that SOCON fixation can produce good stability. The ROM after fatigue test was 3.6 degrees, significantly lower than that of the normal state, indicating that SOCON still produces good stability after fatigue. For the L(4 - 5) segment, the average normal ROM in flexion was 8.6 degrees. In the established spondylolisthesis models, the ROM was 13.7 degrees. After GSS fixation, the ROM was decreased to 3.2 degrees, significantly lower than that in the normal state, indicating that GSS fixation can produce good stability. ROM after fatigue test was 3.7 degrees, significantly lower than that of the normal state, indicating that GSS can produce good stability after fatigue. The ROM measurements in the other five directions were similar to those for flexion described above. CONCLUSION: GSS produces good stability for spondylolisthesis, good fatigue resistance, and can be used in pedicle screw revision surgery. There were no significant differences between GSS and SOCON.

Adult↗

PubMed2002

[Complications associated with the technique of pedicle screw fixation].

OBJECTIVE: To analyze the causes of the complications associated with the pedicle screw fixation during and after operation, as well as the methods for prevention and treatment. METHODS: From January 1988 to December 1999, 475 patients who underwent pedicle screw fixation for various spinal disorders were reviewed retrospectively with statistical analysis. RESULTS: Four hundred and twenty-eight patients (90.1% of all) were followed up for (6.0 +/- 3.7) years. Complications of CD, DRFS, Dick, RF and steffee among 72 cases (80% of all) occurred during the operation of pedical screw fixation in 26 cases with the incidence of 5.5% and after the operation in 64 cases with the incidence of 15%. The incidence of operative/postoperative complications were 0-12.9% in CD, 6.8%-11.9% in DRFS, 7.3%-12.7% in Dick, 2.4%-19.5% in RF, and 10.1%-21.5% in Steffee respectively. The main complications included pseudoarthrosis, pedicle screw broken, pedicle screw malposition and so on. The complications were mainly due to unskilled technique of pedicle screw fixation, implant defect in design and so on. CONCLUSIONS: The complications associated with the technique of pedicle screw fixation must not be neglected. The main causes are laid on unskilled technique of pedicle screw fixation and implant defect in design.

Equipment Failure↗