Shrinkage and biomechanical evaluation of lightweight synthetics in a rabbit model for primary fascial repair.

INTRODUCTION AND HYPOTHESIS: The experiment evaluated different lightweights (<32 g/m(2)) in terms of shrinkage and biomechanics. METHODS: PP-8 (polypropylene of 7.6 g/m(2)), PP-s (PP-8 with absorbable sheets), PP-32 (PP with absorbable fibers; 32.0 g/m(2)) and polyvinylidinefluoride (PVDF; 24.9 g/m(2)) augmented primary sutured repairs of the anterior abdominal wall in a total of 40 rabbits. Rabbits were implanted by only one type of mesh at four abdominal sites. After 7, 14, 30, 60 and 120 days, 2 rabbits were sacrificed per group. Three additional unoperated rabbits were used as controls. Shrinkage and uni-axial tensiometry were evaluated. RESULTS: PP-s implants wrinkled in 70%. PP-32 did not shrink whereas PP-8 and PVDF shrank by 20%. Explants were as strong as the controls; however, they differed in compliance. At lower stress, the tested materials were equally stiff. CONCLUSIONS: The biomechanical behaviour of the tested lightweights does not mimic that of native controls. Weight reduction does not prevent shrinkage.

Prevalence of major levator abnormalities in symptomatic patients with an underactive pelvic floor contraction.

INTRODUCTION AND HYPOTHESIS: Major levator ani abnormalities (LAA) may lead to abnormal pelvic floor muscle contraction (pfmC) and secondarily to stress urinary incontinence (SUI), prolapse, or fecal incontinence (FI). METHODS: A retrospective observational study included 352 symptomatic patients to determine prevalence of LAA in underactive pfmC and the relationship with symptoms. On 2D/3D transperineal ultrasound, PfmC was subjectively assessed as underactive (UpfmC) or normal (NpfmC) and quantified. LAA, defined as a complete avulsion of the pubic bone, was analyzed using tomographic ultrasound imaging. RESULTS: LAA were found in 53.8% of women with UpfmC versus 16.1% in NpfmC (P < 0.001). Patients with UpfmC were less likely to reduce hiatal area on pfmC (mean 7% reduction vs 25% in NpfmC (P < 0.001)). An UpfmC was associated with FI (P = 0.002), not with SUI or prolapse of the anterior and central compartment. CONCLUSION: An underactive pfmC is associated with increased prevalence of LAA and FI.

Experimental comparison of abdominal wall repair using different methods of enhancement by small intestinal submucosa graft.

INTRODUCTION AND HYPOTHESIS: To assess the biomechanical properties of full-thickness abdominal wall defects, either using Native tissues, with or without Overlay, and by substitution of the Defect by small intestinal submucosa mesh. METHODS: Seventy-two rats were divided into three groups according to repair method (Native, Overlay or Defect). At 7, 14, 30, and 90 days, six rats were sacrificed to measure tensile strength, collagen ingrowth, and host response. RESULTS: Explants had comparable strength at 30 days, the majority rupturing at the interface. Afterwards, the Native group was more resistant than both small intestine submucosa (SIS) groups with a more organized fibrotic scar on histology at 90 days. CONCLUSIONS: SIS augmentation of native tissue repair does not increase strength. Replacement of abdominal wall by SIS is equally strong when compared to the SIS-augmented group; however, materials preferably rupture at the site of the implant itself.

Prospective assessment of the endometrium in postmenopausal breast cancer patients treated with fulvestrant.

This prospective study assessed the endometrial effects of fulvestrant, a pure estrogen-receptor antagonist, in postmenopausal women with breast cancer. This single-center study enrolled postmenopausal patients who had an intact uterus at baseline with progressive metastatic breast cancer on tamoxifen followed by an oral aromatase inhibitor (AI). Fulvestrant (250 mg) was administered every 28 +/- 3 days via IM injection. Transvaginal ultrasonography (TVUS) was performed at baseline and after 3 months of therapy. Primary and secondary endpoints were changes from baseline in double endometrial thickness (DET) and uterine volume (UV), respectively. No interventions were performed on any asymptomatic uterine abnormalities that were detected at baseline. In total, 32 women were enrolled. Five patients had no repeat TVUS because of early progression before 3 months, leaving 27 evaluable patients for final analysis. After 3 months therapy, mean DET had significantly decreased by 23.08% (P = 0.010). Mean UV also decreased by 10.88%, although this change was not significant (P = 0.119). After 3 months of therapy, none reported vaginal bleeding, there were no changes noted in most of the uterine pathologies present at baseline and no new uterine abnormalities were detected. We observed that 3 months of fulvestrant treatment resulted in a significant decrease in endometrial growth and a non-significant decrease in UV in postmenopausal women with metastatic breast cancer previously exposed to tamoxifen and AIs. Furthermore, no new uterine pathologies were detected, indicating that fulvestrant behaves as a pure antiestrogen at the uterine level.

Tensile strength and host response towards different polypropylene implant materials used for augmentation of fascial repair in a rat model.

We compared inflammatory response, fibrosis and biomechanical properties of different polypropylene materials from one manufacturer (Tyco Healthcare) in a rat model for primary fascial repair. Full-thickness abdominal wall defects were primarily repaired using 'overlay' technique. Multifilament implants were Surgipro SPM and SPMW, the latter a wider-weave type of the former. Monofilament SPMM implants and polypropylene suture repair (Surgipro II) served as controls. Explants were evaluated macroscopically and changes in thickness, shrinkage and tensile strength were measured. Inflammatory and connective tissue response was assessed on haematoxylin-eosin and Movat stains. Immunohistochemistry was done to localise rat macrophages/monocytes. Multifilament materials induced a shorter acute inflammatory response and more pronounced chronic inflammatory reaction compared to monofilament implants. Macrophages could be found deep in interstices 7.5 by 12.5 microm. No difference in collagen deposition and neovascularisation was observed. At 90 days time point, explants reconstructed with tighter woven multifilament SPM were weaker than sutured or SPMM controls. Overall shrinkage of 10% was comparable for all groups.

Tensile strength and host response towards silk and type i polypropylene implants used for augmentation of fascial repair in a rat model.

OBJECTIVE: We compared host response, architectural integration and tensile strength of two different macroporous silk constructs to a polypropylene type I implant in a rat model for augmentation of primary fascial defect repair. MATERIALS AND METHODS: Animals were sacrificed on days 7, 14, 30 and 90 after implantation. The explants were evaluated macroscopically for infections, herniations and adhesions, mechanically for tensile strength, and histopathologically, to evaluate collagen deposition and inflammatory response. RESULTS: The tensile strength of the explants showed a gradual increase for all materials. All implants uniformly shrank around one fifth by 90 days. In the silk implants, the inflammatory reaction showed a remarkable higher number of foreign body giant cells that characteristically spread from the periphery into implants. Collagen deposition was comparable for all the materials. In Silk a higher grade of neovascularisation was observed. CONCLUSION: Silk explants expressed high tensiometric strength, which was associated with a marked fibrotic process. The silk implants induced a strong foreign body reaction accompanied by microscopic signs of architectural degradation at 90 days. Polypropylene explants showed a more moderate foreign body reaction without architectural disturbance.

Logistic regression model to distinguish between the benign and malignant adnexal mass before surgery: a multicenter study by the International Ovarian Tumor Analysis Group.

PURPOSE: To collect data for the development of a more universally useful logistic regression model to distinguish between a malignant and benign adnexal tumor before surgery. PATIENTS AND METHODS: Patients had at least one persistent mass. More than 50 clinical and sonographic end points were defined and recorded for analysis. The outcome measure was the histologic classification of excised tissues as malignant or benign. RESULTS: Data from 1,066 patients recruited from nine European centers were included in the analysis; 800 patients (75%) had benign tumors and 266 (25%) had malignant tumors. The most useful independent prognostic variables for the logistic regression model were as follows: (1) personal history of ovarian cancer, (2) hormonal therapy, (3) age, (4) maximum diameter of lesion, (5) pain, (6) ascites, (7) blood flow within a solid papillary projection, (8) presence of an entirely solid tumor, (9) maximal diameter of solid component, (10) irregular internal cyst walls, (11) acoustic shadows, and (12) a color score of intratumoral blood flow. The model containing all 12 variables (M1) gave an area under the receiver operating characteristic curve of 0.95 for the development data set (n = 754 patients). The corresponding value for the test data set (n = 312 patients) was 0.94; and a probability cutoff value of .10 gave a sensitivity of 93% and a specificity of 76%. CONCLUSION: Because the model was constructed from multicenter data, it is more likely to be generally applicable. The effectiveness of the model will be tested prospectively at different centers.

Comparison of host response to polypropylene and non-cross-linked porcine small intestine serosal-derived collagen implants in a rat model.

OBJECTIVE: To compare the host response, architectural integration and tensile strength of polypropylene and porcine small intestine submucosa-derived implants in a rat model. DESIGN: Experimental study. SETTING: Center for Surgical Technologies, Faculty of Medicine, Katholieke Universiteit Leuven, Belgium. SAMPLE: Forty-eight adult male Wistar rats weighing 220-250 g randomised to receive either implant. METHODS: Full thickness abdominal wall defects were primarily repaired with polypropylene mesh (Marlex) (MX group) or porcine small intestine submucosa (Surgisis) (SIS group). Animals were sacrificed at 7, 14, 30 and 90 days after implantation. MAIN OUTCOME MEASURES: The presence of herniation, infection and intra-peritoneal adhesions. Change in thickness and tensile strength of implant. Histopathological and immunohistochemical appearances of inflammatory response and collagen deposition. RESULTS: Implants from the SIS group showed a short term increase in thickness in the first 14 days. Formation of adhesions was significantly more intense in the MX group at 30 days, and more extensive in the SIS group at 90 days. Tensile strength increased over time in both groups but was significantly lower in the SIS group than the MX group at 30 days. Implants in the MX group showed a more pronounced inflammatory response and more pronounced new vessel formation than the SIS group. Collagen formation was initially more fibrous and better organised in the MX group but became greater in the SIS group at 90 days. CONCLUSIONS: Biologically derived implant material induced a less pronounced inflammatory response and differences in collagen deposition. At 30 days tensile strength was weaker in the biological implant group but was equivalent by 90 days. These differences may have implications for the in vivo performance of the materials.