Orientation of orthotropic material properties in a femur FE model: a method based on the principal stresses directions.

Most work done on bone simulation has modeled the tissue as inhomogeneous and isotropic even though it is a recognized anisotropic material. Some recent investigations have included orthotropic behavior in bone finite elements (FE) models; however the problem regarding the orientation of these properties along the irregular bone anatomy remains. In this work, a procedure to orientate orthotropic properties in a proximal femur FE model using the directions of the principal stresses produced by a physiological load scheme was developed. Two heterogeneous material models, one isotropic and one orthotropic, were employed to test their influence on the mechanical behavior of the bone model. In the developed orthotropic material, the mechanical properties are aligned with the highest principal stress produced from the successive application of a multi load scenario corresponding to 10%, 30% and 45% of the gait cycle. A solid match between anatomical structures in the proximal femur and the corresponding directions of the main principal stress of the elements of the model suggests that the developed methodology works accurately. The differences found in the stress distributions were small (maximum 7.6%); nevertheless the changes in the strain distributions were important (maximum 27%) and located in areas of clinical relevance.

Evaluation of the female sexual function after vaginal surgery using the FSFI (Female Sexual Function Index).

Urinary Incontinence (UI) and Pelvic Organ Prolapse (POP) have a detrimental effect on Female Sexual Function (FSF). We decided to focus on the effect of vaginal surgery for UI and/or POP on FSF. MATERIALS AND METHODS. 72 women (aged 42-80, mean age: 62) were given the FSFI questionnaire after undergoing the following operations: 54 Tension-Free Vaginal Slings (TFVS), 12 Kelly plications, 3 hysterectomies+Kelly, 2 Tension-Free Vaginal Slings+Kelly, 1 hysterectomy+ Kelly+posterior IVS. RESULTS. 35 women did not answer the questionnaire, 6 women were sexually inactive and answered only partially; 31 patients answered completely. Mean pre- and postoperative scores were, respectively, 25.26 and 25.22 (normal >26.55). 9 patients had a normal preoperative score, whereas 22 a pathological score. The FSFI score did not change postoperatively in 26 women; it worsened in 3 and improved in 2 women treated because of coital incontinence. CONCLUSIONS. Vaginal surgery for UI and/or POP does not seem to affect FSF in the great majority of cases; conditions may worsen or improve, the latter definitely resulting from the treatment of Coital Incontinence. The high number of patients not answering the questionnaire deserves further studies and it could be - at least partially - explained on the basis of psychological and/or cultural problems regarding the highly emotional issues of sex, incontinence and prolapse.

Clinical and pathological characteristics of patients presenting with biochemical progression after radical retropubic prostatectomy for pathologically organ-confined prostate cancer.

INTRODUCTION: To identify risk factors for biochemical failure after radical prostatectomy (RP) in men with pathologically organ-confined (OC) prostate cancer (PCa). MATERIALS AND METHODS: Clinical and pathological features of 350 consecutive patients with pathologically OC PCa treated only with RP and bilateral pelvic lymphadenectomy were analyzed, retrospectively, to identify predictor parameters of prostate-specific antigen (PSA) failure (PSA>or=0.4 ng/ml). The median follow-up was 58.6 months (range: 3.9-183 months). All pathological specimens were step sectioned at 4-mm intervals. Kaplan-Meier progression-free survival rates and chi2 test were adopted for statistical analyses. Multivariate Cox proportional hazard regression models were used to test the association between pathological Gleason score and surgical margin status. RESULTS: 67 patients (19.1%) failed at a median follow-up of 40.2 months (range 1.9-123.3). Age and preoperative PSA failed to reveal significance also in patients with serum PSA>or=20 ng/ml (p=0.46). Patients with T3 clinical stage had a higher progression rate compared to T1C and T2 (43.5 vs. 27.8 and 17.3%, respectively) even if no high statistical significance was pointed out. Presence of perineural infiltration (p=0.04) and prostatic apex infiltration (p=0.74) in the prostatectomy specimens failed to reveal significance. A high pathological Gleason score (>or=7; p=0.0003) and surgical margin status (p<0.0001) were shown to be the most powerful predictive parameters of biochemical progression. CONCLUSIONS: In patients with pathologically OC PCa the presence of a high pathological Gleason score and positive surgical margins appear to represent the most important factors for prediction of outcome following RP.

Plasma chromogranin A in patients with prostate cancer improves the diagnostic efficacy of free/total prostate-specific antigen determination.

INTRODUCTION: We ascertained whether plasma chromogranin A enhances the power of serology assessing prostate cancer (PC). MATERIALS AND METHODS: We studied 56 PC and 83 benign prostatic hyperplasia (BPH) patients. In the sera we measured total prostate-specific antigen (tPSA) and free PSA (fPSA) and calculated the ratio between fPSA and tPSA (f/tPSA). In plasma samples the levels of chromogranin A (CgA) were also assayed. RESULTS: PC patients had higher CgA (p < 0.005) and tPSA (p < 0.05) levels, and a lower f/tPSA ratio (p < 0.001), than BPH patients. When f/tPSA and CgA were combined, the diagnostic sensitivity was enhanced (57-73%), while the specificity had only an 8% reduction (from 89 to 80%). CgA was only correlated to the Gleason PC score (p < 0.05). CONCLUSIONS: CgA determination in PC may enhance the diagnostic accuracy of the f/tPSA assay and provides useful information on the tumor grade.