Synthesis and characterization of Ti-27.5Nb alloy made by CLAD® additive manufacturing process for biomedical applications.

Biocompatible beta-titanium alloys such as Ti-27.5(at.%)Nb are good candidates for implantology and arthroplasty applications as their particular mechanical properties, including low Young's modulus, could significantly reduce the stress-shielding phenomenon usually occurring after surgery. The CLAD® process is a powder blown additive manufacturing process that allows the manufacture of patient specific (i.e. custom) implants. Thus, the use of Ti-27.5(at.%)Nb alloy formed by CLAD® process for biomedical applications as a mean to increase cytocompatibility and mechanical biocompatibility was investigated in this study. The microstructural properties of the CLAD-deposited alloy were studied with optical microscopy and electron back-scattered diffraction (EBSD) analysis. The conservation of the mechanical properties of the Ti-27.5Nb material after the transformation steps (ingot-powder atomisation-CLAD) were verified with tensile tests and appear to remain close to those of reference material. Cytocompatibility of the material and subsequent cell viability tests showed that no cytotoxic elements are released in the medium and that viable cells proliferated well.

Finite element analysis of the strain distribution in the humeral head tubercles during abduction: comparison of young and osteoporotic bone.

AIM: The aim of this work was to design an accurate 3D digital model of the humerus and rotator cuff muscles. This model was then used to study strain distribution in humeral tubercles according to bone density. MATERIALS AND METHODS: The geometry of bone and muscle structures was reproduced using SURFDRIVER software, based on anatomical sections, CT scans and MRI images from the Visible Human Project image library. The contours were transferred to PATRAN software to rebuild volumes and mesh them. Calculations of strains and their distribution were performed using NASTRAN software. All the elements were considered to be isotropes. RESULTS: The study of the distribution of stress magnitude according to the type of bone modeled, shows that some stresses in cortical bone are greater than those in cancellous bone and are also greater in old bone, implying more deformation in old bone at constant force. This study also shows that stresses do not penetrate deeply into cancellous tissue. CONCLUSION: Observing the simulation results led understanding of the pathology of certain fractures of the proximal end of the humerus. This study also helped explain why certain types of osteosynthesis fail due to tubercles reconstruction failures.

[Development of a self-administered questionnaire to assess women's satisfaction with maternity care]. / Développement d'un auto-questionnaire évaluant la satisfaction des femmes à l'égard des maternités.

OBJECTIVES: We describe the development and the validation of a French self-administered questionnaire which measures women satisfaction concerning care given during pregnancy. The analysis includes pregnancy monitoring, hospitalization for delivery and homecoming. METHODS: We considered the content validity, internal-consistency and the reproducibility by test-retest estimates. This survey also compared the characteristics of respondents and non-respondents. RESULTS: Response rate was 61% and the rate of reply per question was greater than 90%. Eleven dimensions are identified by principal-components analysis. Ten of them had good Cronbach's alpha coefficients (0.58 to 0.83). The convergence between open comments and questions and between the different methods to measure satisfaction was good. The test-retest estimates for each dimension were correct. CONCLUSION: This questionnaire is reliable. It is a valid tool for evaluation of satisfaction after pregnancy. Designed to be sent to the woman's residence 2 months after childbirth, it can be easily used in common practice.

The learning curve of total laparoscopic hysterectomy: comparative analysis of 1647 cases.

STUDY OBJECTIVE: To compare the frequency of complications of total laparoscopic hysterectomy performed in the first and more recent years of our experience, and based on that, offer ways to prevent them. DESIGN: Retrospective, comparative study (Canadian Task Force classification II-2). SETTING: University tertiary referral center for endoscopic surgery. PATIENTS: During 1989-1995 and 1996-1999, 695 and 952 women, respectively, with benign pathology. INTERVENTION: Total laparoscopic hysterectomy. MEASUREMENTS AND MAIN RESULTS: No differences in patient characteristics were found between 1989-1995 and 1996-1999. Substantial decreases in major complication rates were noted, 5.6% and 1.3%, respectively. No major vessel injury occurred. Excessive hemorrhage (1.9%) and need for blood transfusion (2.2%) during the first period were statistically higher than in the second period (both 0.1%, p <0.005). Urinary complications (2.2%) including 10 bladder lacerations, 4 ureter injuries, and 1 vesicovaginal fistula occurred more frequently in the first period than in the second period (0.9%), when 6 bladder and 2 ureter lacerations and 1 vesicovaginal fistula occurred (p <0.005). One bowel injury and one bowel obstruction occurred in the first period, but no bowel complications in the second. Between periods, 33 (4.7%) and 8 (1.4%) conversions to laparotomy were necessary. During the first period there were nine reoperations; of six laparotomies, four were due to urinary injuries, one due to heavy vaginal bleeding, and one due to a vesicovaginal fistula; three diagnostic laparoscopies were required due to postoperative abdominal pain. Three reoperations during the second period were two laparoscopies due to heavy vaginal bleeding and one laparotomy due to a vesicovaginal fistula (p <0.005). Statistically significant differences in median (range) uterine weight 179.5 g (22-904 g) and 292.0 g (40-980 g) and operating times 115 minutes (40-270 min) and 90 minutes (40-180 min), respectively, were recorded (p <0.005). CONCLUSION: Laparoscopic hysterectomy was safe, effective, and reproducible after training, and with current technique, had a low rate of complications.

[Post-laparoscopic incisional hernia. Apropos of a case]. / Les hernies incisionnelles post-coelioscopiques. A propos d'un cas.

Incisional hernia occurred in a patient after laparoscopic hysterectomy. The greater omentum was incarcerated in the tract of the suprapubic trocar (12 mm diameter). Diagnosis and treatment were performed during a second laparoscopy procedure. The greater number of trocar instruments and their larger diameter increases the risk of parietal morbidity after laparoscopic procedures. Elective closures of trocar incisions is recommended when exceeding 10 mm. Prevention of extra-umbilical incisional hernias and dehiscences appears to be more effective when suture is performed under laparoscopic vision with the trocar inserted. Both the aponevrosis and the peritoneal membrane should be treated.