Maja Konstantinovic

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.

The biology behind fascial defects and the use of implants in pelvic organ prolapse repair

Implant materials are increasingly being used in an effort to reduce recurrence after prolapse repair with native tissues. Surgeons should be aware of the biology behind both the disease as well as the host response to various implants. We will discuss insights into the biology behind hernia and abdominal fascial defects. Those lessons from “herniology” will, wherever possible, be applied to pelvic organ prolapse (POP) problems. Then we will deal with available animal models, for both the underlying disease and surgical repair. Then we will go over the features of implants and describe how the host responds to implantation. Methodology of such experiments will be briefly explained for the clinician not involved in experimentation. As we discuss the different materials available on the market, we will summarize some results of recent experiments by our group.

The pedicle artery sign based on sonography with color Doppler imaging can replace second-stage tests in women with abnormal vaginal bleeding

Unenhanced transvaginal sonography is not accurate in the detection of endometrial polyps. Currently, second‐stage tests such as saline contrast sonohysterography and office hysteroscopy are used to diagnose endometrial lesions, but both have limitations and side effects. We proposed visualization of the pedicle artery on color Doppler imaging as a sign of polyps.

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

Introduction and hypothesisMajor 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).MethodsA 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.ResultsLAA 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.ConclusionAn underactive pfmC is associated with increased prevalence of LAA and FI.

Fate of collagen-based implants used in pelvic floor surgery: A 2-year follow-up study in a rabbit model

OBJECTIVE The purpose of this study was to compare the long-term host response to 2 different collagen matrices versus macroporous polypropylene mesh. STUDY DESIGN Four full-thickness abdominal wall defects in 35 rabbits were reconstructed with either polypropylene (Prolene), porcine dermal (Pelvicol), or small intestine submucosal collagen matrix (SIS). Animals were sacrificed on day 30, 60, 90, 180, 365, 540, and 720 days to evaluate morphologic and biomechanical properties of explants. RESULTS Prolene provoked a fibrotic reaction within 30 days. SIS was entirely replaced by a thin fibrotic layer within 60 days. Pelvicol was encapsulated, remaining structurally unchanged up to 180 days. Thereafter, half underwent degradation by a foreign body reaction. CONCLUSION Prolene was integrated by an increasingly organised fibrotic scar while SIS was entirely remodelled within 60 days. Pelvicol implants underwent late onset (> or = 180 days) degradation. After 2 years of implantation there were no differences in tensiometric strength between the 3 different materials.

Biomechanical findings in rats undergoing fascial reconstruction with graft materials suggested as an alternative to polypropylene

Graft materials used for pelvic floor reinforcement should still be considered as investigational and, therefore, evaluated experimentally and within clinical trials. The present report describes our biomechanical findings in rats implanted with selected novel implant materials, which in recent years have been suggested as alternatives to plain polypropylene (PP) meshes.

OC264: Correlation between 3D/4D translabial ultrasound and colpocystodefecography in diagnosis of posterior compartment prolapse

Valsalva. Subjective scores for pelvic floor muscle contraction were given on dynamic 3D and 4D using the standardized ICS terminology for assessment of pelvic muscle contraction (non-functioning, weak, normal or strong). Offline analysis of the datasets was undertaken using the software GE Kretz 4D View. Measurements were taken at the level of minimal hiatal dimensions using the inferior margin of the symphysis pubis as reference point on 2D and 3D datasets. On 2D ultrasound the diameter of the minimal anteroposterior (AP) hiatus, vertical displacement of the bladder neck and levator angle were measured. 3D datasets were used for obtaining AP and left–right diameter as well as area of the hiatus. Results: Complete datasets were available for 349 women. The proportional difference (value A rest–value A contraction/value A rest) between the above parameters was calculated. There were significant correlations (P < 0.001) in all parameters between women with no, weak, normal or strong contractions except for vertical bladder neck displacement. The proportional 2D AP difference between rest and contraction measured in the 2D volume seemed to be the strongest predictor, followed by 3D AP diameter and hiatal area. Conclusions: Proportional differences of the AP measurement between rest and contraction in 2D volumes is the easiest method for quantification of pelvic floor muscle contraction. Surprisingly, vertical bladder neck displacement did not seem to be significant between women with no, weak, normal or strong pelvic floor contractions.

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.

OC262: Quantification of the pelvic floor contraction using 3D/4D translabial ultrasound

Objectives: Magnetic resonance imaging (MRI) is the gold standard for the investigation of pelvic floor anatomy and function. The objective of this study was to compare biometric measures obtained by 3D ultrasound and MRI. Methods: In this prospective study, translabial 3D ultrasound and multiplanar MRI were used to assess pelvic floor anatomy in 27 nulliparous female volunteers. 3D ultrasound was performed using a GE Kretz Voluson 730/730 Expert system; MR images were obtained using a Siemens MAGNETOM Avanto 1.5-T scanner. All subjects were imaged supine and after voiding for both modalities. Data were acquired at rest, on pelvic floor muscle contraction and on maximal Valsalva. Results: All subjects were asymptomatic for pelvic floor dysfunction. Mean age was 29.3 (21–41) years, mean body mass index was 22.4 (18–29). Measures of hiatal diameters and areas obtained on MRI and 3D ultrasound were distributed normally. Sagittal hiatal diameters correlated at r = 0.533, P = 0.005 at rest, with ranges of 3.8–6.0 cm for MRI and 3.9–5.7 cm for ultrasound. On Valsalva, these figures were r = 0.658, P < 0.001, with ranges of 2.9–8.0 cm on MRI and 3.7–7.3 cm on ultrasound. On pelvic floor muscle contraction, the correlation was r = 0.503, P = 0.01 with ranges of 3.0–5.9 cm on MRI and 3.1–4.7 cm on ultrasound. As regards area measurements, correlations were r = 0.648 at rest and r = 0.542 on Valsalva (P < 0.01). Ranges were 9.1–18.1 on MRI vs. 9.2–17.8 on ultrasound at rest and 6.53–36.5 cm2 on MRI vs. 10.7–27.9 cm2 on ultrasound on Valsalva. There was a tendency for larger MRI measurements on Valsalva (P < 0.01 for area and midsagittal diameter). Repeatability measures were good to excellent for both methods. Conclusions: In this study of 3D ultrasound and MRI of the levator hiatus, correlations between methods were moderate but highly significant. MRI seemed to yield higher measurements on Valsalva, suggesting difficulties in identifying the plane of minimal dimensions during maneuvers that led to displacement of this plane.

Porous Acellular Porcine Dermal Collagen Implants to Repair Fascial Defects in a Rat Model: Biomechanical Evaluation up to 180 Days

Aim: To investigate the biomechanical properties of porous collagen matrices in a rat abdominal wall defect model. Study Design: 112 rats were implanted with non-cross-linked InteXèn LP, cross-linked Pelvicol, and two investigational acellular collagen matrices (ACMs) sterilized either with ethylene oxide (ACM ETO) or γ-irradiation (ACM GI). After 14, 30, 90 and 180 days, 7 animals per group were sacrificed to document adhesions, herniation, infection, stress resistance and histology. Results: The 2 sterilization methods did not cause measurable differences between ACMs. Pelvicol was more resistant than ACMs but showed degradation at 90 days without loss of strength. InteXèn LP became remodeled as a thin fibrous scar and was more resistant at all time points; however, some animals developed bulging. Conclusions: Non-cross-linked InteXèn LP became remodeled by 180 days with remarkable stress resistance. Despite cross-linking Pelvicol showed degradation. Comparable but investigational ACM explants were less resistant without morphologic differences to explain this.