Polypropylene Prosthesis Research Articles

New antibiotic-eluting mesh used for soft tissue reinforcement

The surgical implantation of prostheses for soft tissue repair may be followed by post-operative mesh-related infection, a significant and dramatic complication, that is treated by mesh removal. A new antibiotic-eluting mesh has been manufactured on pre-existing polypropylene prostheses using an airbrush spraying technology. Among the degradable polymers tested as coating agents and drug reservoirs, poly(ε-caprolactone) (PCL), which is deposited after heating, provides a homogeneous, regular and smooth shell around the polypropylene filaments of the mesh without dramatically altering the biomechanical properties of the new modified mesh. An anti-infective drug (e.g. ofloxacin) is incorporated into this polymeric coating giving a limited burst effect followed by sustained drug diffusion for several days. An ofloxacin-eluting mesh has demonstrated excellent antibacterial activity in vitro on Escherichia coli adherence, biofilm formation and inhibitory diameter, even with low drug loads. Although further in vivo investigations are required to draw conclusions on the anti-infective effectiveness of the coated mesh, the airbrush coating of ofloxacin–PCL on existing prostheses is already potentially appealing in an effort to decrease post-operative infection.

Traumatic hemipelvectomy in children: report on 2 survivors with urological involvement

Traumatic hemipelvectomy through the sacroiliac joint is a devastating injury, mainly because of motor vehicle accidents. Recent improvements in prehospital trauma care have increased the chances of survival for victims. Besides amputation of the lower limb, associated complications usually involve digestive and urological systems. We report on 2 pediatric patients from 2 different European countries. Patient 1 A 9-year-old boy suffered uprooting of his left lower limb, laceration of the rectum and anal sphincter, as well as an injury to distal urethra with partial loss of cavernous bodies. Initial management included a colostomy and an essay of contention by means of a polypropylene prosthesis that had to be removed in the following months. After several attempts at urethral reconstruction, he underwent a Mitrofanoff derivation. Patient 2 An 18-month-old girl lost her left lower limb and suffered severe lacerations of bladder and rectum. Among other measures, management included a colostomy, a skin graft, and 2 attempts at reconstruction of her bladder neck, including a modified Casale procedure (cecum and ileocecal appendix were in a high position that made a Mitrofanoff derivation impossible) and a Malone procedure. To the authors' knowledge, she would be the youngest reported survivor of this kind of injury.

Double-Mesh Technique for Correction of Abdominal Hernia Following Mammary Reconstruction Carried Out with Bipedicled TRAM Flap and the Primary Closing of the Donor Area by Using a Single Polypropylene Mesh

Mammary reconstruction by using the transverse myocutaneous flap of the abdominal straight muscle (TRAM) is still an option well accepted in many parts of the world. However, bipedicled TRAM flaps are associated with greater morbidity of the abdominal donor area. The aim of this study was to describe an efficient technique for correcting the delayed defects of the abdominal wall following mammary reconstruction carried out with bipedicled TRAM flaps by using two polypropylene prostheses overlapped in different anatomical planes. At Hospital Estadual Sumaré at Universidade Estadual de Campinas, 18 women who underwent unilateral mammary reconstruction with bipedicled TRAM flaps and immediate fixation of two rectangular flaps of polypropylene mesh on the donor area were assessed. Later on, three patients (16.7%) presented with deformity of the anterolateral abdominal wall in the donor area. Each of these herniations was corrected by fixing two polypropylene meshes in different anatomical planes: the first mesh, which was bigger and preperitoneal, was fixed from the costal borders until the pubis; the second mesh was fixed from the external oblique muscle to the contralateral external oblique muscle, remaking the median line. All patients were followed up for at least 18 months, without any signs of relapse, abdominal asymmetry, or chronic pain and with satisfactory functional results. The correction of delayed deformities of the abdominal wall after mammary reconstruction with bipedicled TRAM flaps using double mesh was carried out in an effective and secure way, providing an interesting surgical option for mastologists and plastic and general surgeons.

Biomechanical analysis of polypropylene prosthetic implants for hernia repair: an experimental study

Background Although polypropylene (PP) is the most common biomaterial used for ventral and inguinal hernia repairs, its mechanical properties remain obscure. Methods Retraction, solidity, and elasticity of 3 large pore-size monofilament PP prostheses, 1 heavy-weight PP (HWPP), a second low-weight PP, and a third coated with atelocollagen were evaluated in a rabbit incisional hernia model. A small pore-size multifilament PP implant (MPP) also was tested. Results Unlike pore size, the weight of the prosthesis was not an influencing factor for retraction. Atelocollagen coating reduced retraction ( P < .05). HWPP and MPP were less likely to rupture ( P < .05). HWPP had comparatively better elasticity ( P < .05), whereas MPP supported the greatest elastic force ( P < .05). Nevertheless, the amount of shrinkage of MPP (30% of the original size) made this prosthesis unusable. Conclusions In this study, HWPP presented the most advantageous biomechanical compromise for hernia surgery.

Factors Affecting Tissue Culture and Transplantation Using Omentum

In tissue engineering, a stable tissue layer and blood vessels are required for complete tissue formation, to provide structural strength and thickness and to supply oxygen and various nutrients. However, this has not been achieved using in vitro tissue-engineered culture techniques, thus many tissue engineering studies of trachea, bladder, and intestine reconstruction have used omentum. However, many factors critical to cell culture and transplantation using omentum have not yet been studied. For these reasons, we conducted a study of artificial trachea reconstruction in dogs using a poly(lactic-co-glycolic acid) (PLGA) porous scaffold, polypropylene prosthesis, and PKH26-labeled cells. We analyzed factors affecting tissue-engineered reconstruction using omentum, such as cell distribution and formation of cell layer and stability of transplant shape on omentum. As a result, we classified failure factors for tissue-engineered application of omentum and suggested three considerations for effective use of omentum in tissue engineering. Our observations may aid in the design and execution of future studies of omentum usage in tissue engineering.

New Surgical Procedures for Pelvic Organ Prolapse: Insertion of a Tension-free Vaginal Mesh and Laparoscopic Sacrocolpopexy

Pelvic organ prolapse is characterized by a lack of pelvic floor support causing the pelvic organs and vaginal wall to protrude. For many decades, suture repair techniques have been the primary choice of surgical treatment when indicated. Traditional surgical techniques are, however, frequently associated with high rate of anatomical recurrence. Since 2004, vaginal mesh surgery with a tension-free vaginal mesh has emerged as an effective method of pelvic floor reconstruction, applicable to most types of pelvic organ prolapse. Gynemesh®, a thin, highly porous synthetic polypropylene prosthesis, is inserted as a hammock under the bladder, applied laterally on the arcus tendineus fascia pelvis, and retained by 2 nonsecured bilateral transobturator arms. A posterior interrectovaginal prosthesis is inserted in front of the rectum and applied laterally on the levatores ani and is retained by bilateral lateral arms secured to the median part of the sacrospinous ligament. Laparoscopic sacrocolpopexy is another new procedure for the treatment of pelvic organ prolapse. This method is especially suitable for patients younger than 50 years. Because of possible complications, surgeons must learn the technical details of these procedures before performing them and choose the best surgical method according to patient's age, symptoms, and complications.

Retraction and fibroplasia in a polypropylene prosthesis: experimental study in rats

The treatment of hernia, independent of anatomical site and technique utilized, generally involves using prostheses, which may cause complications, despite their unarguable advantage in allowing safe reinforcement. An example of this is possible retraction, which causes discomfort and hernia recurrence. Polypropylene is still the most often used biomaterial of the great number available. The purpose of this study is to evaluate the amount of retraction of the polypropylene mesh, as well as the histological reactions that accompany this phenomenon. Polypropylene meshes (Marlex) were inserted in an anterior position to the whole abdominal aponeurosis of 25 Wistar rats (Rattus norvegicus albinus). The animals were divided into groups and another intervention was performed 7, 28, and 90 days later to measure the dimensions of the prostheses and to calculate the final area. Histological analysis was performed with hematoxylin-eosin to evaluate neutrophils, macrophages, giant cells, and lymphocytes surrounding the mesh threads in ten random fields of each slide. Seven days after the mesh was inserted, the mean rate of retraction was 1.75% (P = 0.64); at 28 days, it was 3.75% (P = 0.02); and at 90 days, it was 2.5% (P = 0.01). As to the histological analysis, there was a total decline of neutrophils and a progressive increase of macrophages, giant cells, and lymphocytes proportional to the post-implant time of the mesh (P < 0.05). There was a statistically significant retraction of 3.75% at 28 days and 2.5% at 90 days after the prosthesis was inserted. There is a well-established sequence of cellular events which aim at synthesizing new connective tissue to reinforce the mesh.

Experimental biomechanical evaluation of polypropylene prostheses used in pelvic organ prolapse surgery

Although polypropylene (PP) is the most common biomaterial used to repair genital prolapse via vaginal route, its mechanical properties however remain obscure. An abdominal hernia rabbit model was used to evaluate retraction, solidity, and elasticity of the principal types of PP prostheses currently available, i.e., three large pore size monofilament prostheses, one heavy weight (HWPP), a second low weight (LWPP), and a third coated with atelocollagen (CPP). A small pore size multifilament PP (MPP) implant was also tested. In comparison with HWPP (12%), LWPP (15%), and MPP (30%), CPP had less retraction (8% of the original size). Unlike pore size, weight prosthesis is not an influencing factor for retraction. Atelocollagen coating reduced retraction. HWPP and MPP were the most solid prostheses. MPP supported the greatest elastic force. When the biomechanical parameters were comparatively assessed, HWPP was considered to have the most advantageous properties for prolapse surgery.

Vaginal reconstructive surgery for severe pelvic organ prolapses: A ‘uterine-sparing’ technique using polypropylene prostheses

Objective The Ulmsten's “Integral Theory” for pelvic floor dysfunctions is based on the need to reinforce fascias and ligaments with prostheses to obtain a reconstitution of the pelvic floor's anatomy. In September 2004 we developed a “uterine-sparing” surgical technique to correct such pathologies and in this paper we present results obtained. Primary outcome was to evaluate the technique's efficacy, secondary outcomes the resolution of stress urinary incontinence, postoperative pain (VAS scale), safety and complications. Study design This prospective study included patients affected by stage 3 and 4 uterine-vaginal prolapse who wished to conserve their uterus. Those with (1) minor degrees of severity, (2) unfit for surgery, (3) with a clear indication to hysterectomy (i.e. endometrial cancer), (4) with an elevated operative risk (American Society of Anaesthesiologists—ASA score III and IV), (5) previous vaginal surgeries and (6) with moderate/severe defecation problems were excluded. The technique consisted in a sacrospinous colposuspension with polypropylene mesh. The pelvic status was classified according to the international Pelvic Organ Prolapse staging system (POP-Q). Postoperative pain was scored with the VAS Scale. All patients were given the King's Health questionnaire, the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12) and the Wexner questionnaire. Results From September 2004 to November 2006 we treated 80 patients. Polypropylene prostheses (Gynemesh-Soft PS, 10 cm × 15 cm – GyneMesh, Gynecare Ethicon – Somerville, NJ, USA) were used to reconstruct the pubo-cervix or the recto-vaginal fascia. We performed an anterior-central vaginal reconstruction in 35 (43.8%) patients, central-posterior in 25 (31%) and total reconstruction in 20 (25%). The median follow-up was 21 months (range 18–26). The severe pelvic prolapse, evaluated with the POP-Q System, was completely treated in all the patients and no recurrences were observed. The urodynamic examination showed a complete resolution of the stress urinary incontinence in 10 patients (83%). Sexual activities improved in all patients. We recorded three vaginal erosions and one patient complained of a postoperative dyspareunia. Conclusions This pilot study suggests that our technique is safe and effective and can efficiently repair the pelvic organs prolapse, without undergoing hysterectomy and with a low rate of vaginal erosions.

Incisional Hernia after McBurney Incision: Retrospective Case‐control Study of Risk Factors and Surgical Treatment

Few reports have dealt with incisional hernias originating at a McBurney incision after appendectomy. The purpose of the present study was to identify risk factors for development of incisional hernia at a McBurney incision, and to describe our experience with the treatment of this kind of hernia. We reviewed 4,862 files of patients older than 15 years of age operated on for acute appendicitis. Some 4,523 (93%) of that group were operated on through a McBurney incision, and 34 (0.7%) of them developed incisional hernia. To identify risk factors for development of incisional hernia we used binary logistic regression analysis. The following risk factors were identified: female gender (p = 0.011), diabetes (p < 0.0001), peritonitis, abscess or phlegmon as the cause of the first operation (p = 0.009), wound infection (p = 0.034), seroma (p = 0.023), the use of catgut to suture the aponeurosis (p < 0.0001), and interrupted suture to the aponeurotic layer (p = 0.046). Twenty-two hernias were repaired with Mayo-herniorrhaphy and 12 with a subaponeurotic polypropylene prosthesis. Recurrences developed in 3 patients, none in hernias repaired with prosthesis. The risk of incisional hernia after a McBurney incision for acute appendicitis was very low; we recommend the repair of this uncommon incisional hernia with current standard tension-free prosthetic techniques.

Postimplant Behavior of Lightweight Polypropylene Meshes in an Experimental Model of Abdominal Hernia

Background. Over the years, reticular prostheses have undergone changes in their structure and composition to give rise to today's partially absorbable lightweight meshes. This study was designed to assess the biological and biomechanical behavior of these prostheses to establish whether they offer any advantages over nonabsorbable lightweight polypropylene prostheses. Materials and Methods. 7 × 5 cm defects were created in the anterior abdominal wall of New Zealand White rabbits and repaired by securing different prostheses to the edges of the defect with a running 4/0 polypropylene suture. The lightweight biomaterials compared were two nonabsorbable meshes: Parietene® and Optilene elastic®, and two partially absorbable prostheses: Vypro II® and Ultrapro®. At 14 and 90 days postimplant, tissue/prosthesis specimens were subjected to histological, immunohistochemical, shrinkage, and biomechanical analyses. Results. Adhesion formation on the peritoneum-facing surface of the meshes was significantly less extensive in the meshes with absorbable components at 90 days postimplant. The newly formed tissue around the prosthetic filaments was comprised of collagen fibers, fibroblasts, blood vessels, and macrophages. The partially absorbable meshes showed higher macrophage proportions (due to remnants of absorbable material and their structure) than the nonabsorbable meshes at 90 days, although differences were not significant. At 90 days postimplant, similar tensile strengths were recorded for all the implants. Conclusions. All the prosthetic materials induced good host tissue ingrowth, with no significant differences in tensile strength observed. Our findings suggest that partially absorbable lightweight prostheses could offer advantages over nonabsorbable lightweight meshes since less foreign material persists in the recipient, improving abdominal wall compliance.

New Surgical Procedures for Pelvic Organ Prolapse: Tension-free Vaginal Mesh

Pelvic organ prolapse (POP) is characterized by a lack of pelvic floor support, which causes the pelvic organs and vaginal wall to protrude. For many decades, suture repair techniques have been the primary choice of surgical treatment when indicated. Traditional surgical techniques are, however, associated with a high recurrence rate. Since 1996, vaginal mesh surgery for treatment of POP has been performed with several types of procedure. Among these procedures, the tension-free vaginal mesh (TVM) procedure is expected to be effective for reconstruction of the pelvic floor and to be applicable to almost all types of POP. Gynemesh (Gynecare Ethicon, Somerville, NJ, USA), a thin, high-porosity synthetic polypropylene prosthesis, is inserted as a hammock under the bladder, applied laterally on the arcus tendineus fasciae pelvis, and retained by two unsecured bilateral transobturator arms. A posterior interrectovaginal prosthesis is inserted in front of the rectum and applied laterally on the levatores ani, retained by a bilateral lateral arm secured to the median part of the sacrospinous ligament. We used TVM to treat 40 cases of POP from May 1, 2007, to June 30, 2008. We have applied both anterior and posterior meshes in 29 cases and an isolated anterior mesh only in 10 cases. The TVM was quite effective for all types of POP, including recurrent cases. However, bladder injury (3 cases) and rectal injury (1 case) occurred during this period. We believe that TVM is a decisive innovation in the treatment of POP, but surgeons must be familiar with its technical details before practice.

Prospective study on the effects of a polypropylene prosthesis on testicular volume and arterial flow in patients undergoing surgical correction for inguinal hernia

To evaluate testicular volume and arterial flow in patients undergoing surgical correction for inguinal hernia, with polypropylene prosthesis. This was an observational prospective clinical study on 39 male patients with unilateral inguinal hernia of types III A and III B according to the Nyhus classification who underwent surgical correction with implantation of a polypropylene prosthesis by means of the Lichtenstein technique. The patients were evaluated using Doppler ultrasound before the operation and selectively at the third and sixth months after the operation. The variables studied were testicular volume, systolic and diastolic velocity, resistance index and pulsatility index. No statistically significant alterations in the variables studied were observed over the course of time: testicular volume (p= 0.197); systolic velocity (p= 0.257); diastolic velocity (p= 0.554); resistance index (p= 0.998); and pulsatility index (p= 0.582). No alteration in testicular volume and arterial flow over a six-month period was observed among patients who underwent surgical correction for inguinal hernia using a polypropylene prosthesis.

Partially absorbable meshes for hernia repair offer advantages over nonabsorbable meshes

Background The aim of this study was to establish whether new prosthetic materials with absorbable components, designed to reduce the amount of foreign material in abdominal wall repair, offer advantages over the conventional polypropylene meshes. Methods Seven × 5 cm defects created in the anterior abdominal wall of New Zealand white rabbits were repaired by using a nonabsorbable polypropylene prosthesis (Surgipro; Tyco, Barcelona, Spain) or 1 of 2 partially absorbable prostheses available on the market (Vypro II and Ultrapro; Johnson & Johnson, St. Stevens-Woluwe, Belgium). At 14 and 90 days after surgery, tissue/prosthesis specimens were subjected to histological studies, biomechanical strength tests, and shrinkage evaluation. Results At 90 days, the absorbable filaments of Vypro II had been completely reabsorbed, whereas Ultrapro only showed signs of biodegradation in a few zones. Host tissue infiltration and collagen I deposition in the 3 reticular meshes was optimal. Macrophage counts, mesh shrinkage, and biomechanical resistance values were similar. Conclusions Partially absorbable prostheses perform as well as the standard polypropylene mesh and have the benefit that less foreign material remains in the recipient, without compromising mechanical resistance.

Are the outcomes of emergency Lichtenstein hernioplasty similar to the outcomes of elective Lichtenstein hernioplasty?

Background The safe use of polypropylene prosthesis for the repair of complicated inguinal hernias has been established even when small bowel resection was required. Few reports have completely addressed this subject; none have compared the outcomes of emergency and elective Lichtenstein hernioplasty. Methods From January 2001 to December 2003, 343 patients were electively operated for inguinal hernia and 62 for complicated inguinal hernia. A follow-up period of 17–57 months using the Quantitative and Qualitative Measurement Instrument for evaluation of Lichtenstein hernioplasty outcomes (QQMI) was completed for 48 emergency patients and 326 elective patients. Results The mean QQMI score showed that most patients felt that the outcomes of their surgery were very good or excellent. Mean QQMI score for elective surgery was 10.1 and 9.5 for emergency surgery. Conclusions The outcomes of emergency Lichtenstein hernioplasty were inferior to the outcomes of elective Lichtenstein hernioplasty.

On the Use of Unsealed Polypropylene Mesh as Tracheal Replacement

The necessity of a cervical tracheal replacement arises with thyroid carcinoma, which occasionally infiltrates the trachea extensively, the rare primary tracheal tumors and, sporadically, benign stenoses. In the present study, we used an uncoated porous polypropylene prosthesis as cervical tracheal replacement in sheep. Specifically, we implanted a tracheal prosthesis of polypropylene mesh as a cervical tracheal replacement in five sheep, protecting the airways with self-expanding stents. Healing-in of the prostheses was checked bronchoscopically. The animals were killed after increasing survival times (7, 28, 64, 68, and >90 days), and incorporation of the prosthesis was examined macroscopically, microangiographically and histologically. Although medium-term survival was possible with a sufficiently wide airway, all animals were ultimately euthanized because of complications (airway stenosis, prolapse of prosthesis). Nevertheless, the results show that replacement of the cervical trachea with a polypropylene mesh can be successful under different experimental conditions.

Light weight meshes in incisional hernia repair

Incisional hernias remain one of the most common surgical complications with a long-term incidence of 10-20%. Increasing evidence of impaired wound healing in these patients supports routine use of an open prefascial, retromuscular mesh repair. Basic pathophysiologic principles dictate that for a successful long-term outcome and prevention of recurrence, a wide overlap underneath healthy tissue is required. Particularly in the neighborhood of osseous structures, only retromuscular placement allows sufficient subduction of the mesh by healthy tissue of at least 5 cm in all directions. Preparation must take into account the special anatomic features of the abdominal wall, especially in the area of the Linea alba and Linea semilunaris. Polypropylene is the material widely used for open mesh repair. New developments have led to low-weight, large-pore polypropylene prostheses, which are adjusted to the physiological requirements of the abdominal wall and permit proper tissue integration. These meshes provide the possibility of forming a scar net instead of a stiff scar plate and therefore help to avoid former known mesh complications.

Incisional hernioplasty with a 'flower' polypropylene prosthesis.

Incisional hernioplasty with a 'flower' polypropylene prosthesis.

Composite prostheses for the repair of abdominal wall defects: effect of the structure of the adhesion barrier component

The component of a composite prosthesis, which makes contact with the visceral peritoneum, can be reabsorbable or non-reabsorbable, and laminar or reticular. This study was designed to determine whether the composition of this second, barrier component could improve its behavior at this interface. Abdominal wall defects in rabbits were repaired using a polypropylene prosthesis (PP), or the composites Sepramesh (PP + h) or Vicryl (PP + v). Fourteen days after surgery, the implants were evaluated by light and scanning electron microscopy, and immunohistochemistry. Prosthetic areas occupied by adhesions (PP: 71.08 +/- 5.09, PP + h: 18.55 +/- 4.96, P + v: 69.69 +/- 16.81%), neoperitoneal thickness (PP: 256.17 +/- 21.68, PP + h: 83.11 +/- 19.63, PP + v:213.72 +/- 35.90 microm) and macrophage counts (PP: 8.73 +/- 1.16, PP + h: 27.33 +/- 4.13, PP + v: 31.24 +/- 3.08%) showed significant differences (P < 0.05). The tested biomaterials induced an optimal recipient tissue infiltration. Least adhesion formation was observed on the PP + h implants. This suggests that the second component, although reabsorbable, should be smooth in structure.

Improved surgical mesh integration into the rat abdominal wall with arginine administration

Prosthetic meshes are used as the standard of care in abdominal wall hernia repair. However, hernia recurrences and side effects remain unsolved problems. The demand by health care providers for increasingly efficient and cost-effective surgery encourages the development of newer strategies to improve devices and outcomes. Here, we evaluated whether l-arginine administration was able to ameliorate long-term polypropylene prostheses incorporation into the abdominal wall of Sprague–Dawley rats. Meshes were placed on-lay and continuous l-arginine was administered. In vivo biocompatibility was studied at 7, 25 and 30 days post-implantation. Effectively, l-arginine administration in combination with mesh triggered subtle changes in ECM composition that impinged on critical biochemical and structural features. Lastly, tensile strength augmented and stiffness decreased over the control condition. This could help to restructure the mechanical load transfer from the implant to the brittle surrounding tissues, i.e., impact load and fatigue load associated with mechanical tensions could be distributed between the mesh and the restored tissue in a more balanced manner, and ultimately help to reduce the incidence of loosening, recurrences, and local wound complications. Since the newly formed tissue is more mechanically stable, this approach could eventually be introduced to human hernia repair.