Roxana Bohîlțea

Properties Analysis of Biological Grafts Used in Pelvic Surgery

Pelvic surgery addresses congenital malformations like Mullerian anomalies, pelvic organ prolapse or after radical intervention, while constructive surgery involves treatment of congenital/iatrogenic absence of organs: uterus or vagina. Intuitively, inert and nondegradable biomaterials appear ideal for this purpose, but surgical reality is that the persistence of a permanent foreign body in the wound has a lot of clinical postoperative disadvantages. This paper aims to discuss the properties of the biologic grafts, detailing the structure of biologic extracellular matrix, the biomechanical properties of biological grafts and the use of extracellular matrix in reconstructive pelvic surgery. A biologic graft used in pelvic surgery is a tridimensional extracellular matrix, acellular and of animal origin. It has as a low risk of transmission of viral and prionic infections and determines reduced inflammatory reaction and a low risk of rejection. The absence of crosslinking facilitates the colonization of the mesh by the host´s cells, thus avoids the foreign body reaction represented by the encapsulation of the mesh by the host. Our experience with clinical use of biological acellular grafts in reconstructive pelvic surgery includes oncoplastic surgery like in cases of vulvar cancer or neovagina reconstruction for Rokintansky syndrome, complications after prolapse surgery treated with polypropylene meshes or relapsing recto-vaginal fistulas. The biomechanical properties evaluated by tensile stress and elastic modulus revealed that biologic grafts with moderate collagen infiltration are the strongest. The degree of cross-linkage influences the rate of degradation and the degree of the inflammatory response triggered by the host organ. Cross-linked collagenous matrices induce little cell infiltration hence there is limited collagen remodeling and graft degradation. On the other hand, in non-cross- linked xenografts cell infiltration is greater with faster degradation rate and collagen production. The decrease in the mechanical strength of the graft materials is related to the lack of collagen infiltration into the material. In conclusion, taking into account the biomechanical properties of biologic grafts, these may be used in reconstructive pelvic surgery and oncoplastic surgery with little complications and good clinical results. They can be attached to large mucosal defects and on potentially septic tissue, they are mechanically resistant and they can be sutured on surrounding healthy tissue.

Synthetic Mesh Used in Gynecologic Reconstructive Surgery for Pelvic Floor Disorders

Pelvic floor disorders including stress urinary incontinence and pelvic organ prolapse represent a challenge for gynecologist or urogynecologist even nowadays. Conservative treatment for these conditions proves its effectiveness only in few cases selected from early forms of incontinence or prolapse the most cases being solved surgically. The introduction of the procedure imagined by Petros and Ulmsten, known as TVT (Trans Vaginal Tape) in which the medium urethra is supported by a synthetic tape produced in 1996 a revolution in the surgical treatment of stress urinary incontinence. Radical changes also appeared in pelvic organ prolapse surgery extrapolating the hernia repair procedure by using synthetic mesh. After nearly 20 years of experience the mesh surgery is today a common practice in urogynecology. Between 2011 and 2015 we operated in private practice a total number of 297 cases of which 187 cases of stress urinary incontinence and 110 cases of pelvic organ prolapse. From these 86 (78,1%) cases were represented by cystoceles, associated with early apical prolapse or rectoceles, 18 (16,3%) cases by apical prolapse (grade III-IV) and 6 (5,4%) cases by posterior compartment prolapse alone. We performed mesh surgery in 32 (29%) cases represented mainly by anterior compartment prolapse. In 6 (18,7%) cases we founded mesh extrusion which required partially resection. In two cases we performed large resection of anterior vaginal wall required grafting with acellular second generation graft. In all cases with mesh extrusion the biomechanical analysis revealed significant decrease in effective porosity of the mesh due to excessive tensioning or folding of the mesh. The use of mesh in stress urinary incontinence and pelvic organ prolapse represent a justified alternative in selected cases. The specific complications due to meshes are more frequent in prolapse surgery compared to stress urinary incontinence. In all cases altered effective porosity due to technical defects in surgery represents the leading cause.

The Use of Mersilene Tape in Transabdominal Cerclage

Aim: The purpose of this article is to show the use and utility of mersilene tape in medical procedures, such as transabdominal cerclage (TAC). Material and methods: Based on their biomechanical properties, we present our experience with mersilene tape used as treatment for cervical incompetence. Cervical insufficiency or cervical incompetence is defined as asymptomatic cervical shortening and dilatation with the absence of detectable uterine contractions. The mechanical properties of cervical tissue are derived from its extracellular matrix and its most important constituent the fibrillar collagen, alongside other constituents such as proteoglycans, hyaluronic acid, elastin, and water. In the absence of the uterine contractions, the cervix is loaded by intrauterine pressure (including the weight of the growing fetus and amniotic sac), the gravity as well as passive pressure from the uterine wall. These forces also depend on the support action of pelvic floor structures and abdominal wall. The static load resulting from the combination of uterine growth, hydrostatic pressure and gravity seems to be the dominant determinants that cause cervical shortening. The placement of the mersilene tape acts as a barrier between the intrauterine pressure and the cervix. The main advantage of the TAC procedure is the placement of the nonabsorbable suture (mersilene tape at the level of the internal os, avoiding the placement of a vaginal foreign body and subsequently increasing the risk of ascending lower genital tract infection, decreased incidence of slippage, and the ability to leave the stitch in place between pregnancies. Results: The follow-up was without complications regarding the pregnancies treated with transabdominal cerclage. None of the pregnancies terminated prematurely as related to the presence of the tape, but it necessitates to be performed a caesarean section for delivery. Conclusions: Mersilene tape is safe and useful in different medical procedures, including transabdominal cerclage during pregnancy.

Non-invasive prenatal testing - a new method in improving first trimester screening for chromosome-related abnormalities

In the last 15 years, major advances have been made in prenatal screening. Cohort studies have led to an understanding of the causes of many common diseases that are determined by the combined effects of genetic and phenotypic factors. Non-invasive prenatal testing (NIPT) is a technology used to isolate deoxyribonucleic acid (DNA) placental fragments from the mother’s blood at as early as 10 weeks of gestation, using cell free fetal DNA technology. NIPT screens for trisomy 13,18 and 21 for sex chromosome abnormalities with a high detection rate. Cohort studies have shown a high detection rate and a low false positive rate for NIPT, but it is still considered a screening test and not diagnostic. It is recommended confirmation in case of a positive test, with a diagnostic procedure as chorionic villus sampling or amniocentesis. It is essential that NIPT be used ethically and effectively. Because of its high sensitivity (true positive rate) and its specificity (true negative rate) many recommend that NIPT should be used as a diagnostic method. However, today NIPT is used as a screening method, an attractive alternative to the serum screens and invasive test currently in use. There is a continuing decline in sequencing costs and hopefully, soon, the cost will be reduced.