Sling Types & Informed Consent
Recently I have heard from women who wonder about certain materials that some doctors are now using as alternative slings. They asked me did I have any research they could read and because I didn’t, I began researching. However, I found it was very difficult. I put certain words into a search engine but came up with so many other things I was not looking for and it was quite frustrating and time consuming. So when one woman suggested I asked a really good source I trusted, I did so. I had asked about Bovine material and I received back a key word plus an idea of why this material is not often used. This was the reply.
“Bovine skin (dermis) is an organic material. Most of it will be reabsorbed quickly and not producing any cure. Some can cause long term complications due to reaction to the tissues.”
I knew I needed more information not just on bovine, but also other materials offered by some doctors now, and others have tried in the past and no longer use it. Before this note, I had not thought of adding dermis on the end and when I did I first had to look past many lawyers’ links, then kept checking into various links until I found one that covered many types of materials and perhaps all of them.
Before I give you that link I would like to ask you what you think informed consent is. I am sure it could be argued in many ways, but for me it is about being given information at least a few days before surgery and definitely in the form of paper or email I can read, about any product that is going into my body, that is not my own tissue. We all know doctors do not make these sling products and because they are all made by companies, there is a paper trail. Right now there are so many women going to trial with many companies who make some of these products, it would stand to reason that a doctor would provide a pamphlet direct to the patient either by email or in their hand to make sure women are giving informed consent. However giving information is still up to the physician to hand to a patient and there could easily be little of this happening and no way to otherwise prove it is as feminine issues are private to most women. If pamphlets are not available before your surgery, because they have been given out, then medical people or those who work for them, can go to the site and retrieve a copy of what will be used and printed or emailed to the patient. There is absolutely no excuse for the patient not being given this information and as far as I am concerned, a talk by the doctor is not part of the deal. They could be biased for various reasons. One reason could be financial gain. Mesh slings are available to just about any doctor who sets up a practice and decides they can fix women’s issues. That is only part of the problem however. Mesh and other purchased tissue slings are speedier to use than a woman’s tissues. It takes specialized training a lot of skill to use a woman’s tissue, so a doctor may be tempted to speed up the process by using other forms of sling, thinking his/her time is valuable. One suggestion, but it is up to you what you choose to do. All I can tell you is that mesh slings will definitely change your life for the worse. Perhaps not now but in years to come. Do you really want to play Russian Roulette? I cannot tell you about the others because I have not experienced them, but you have to decide what to do, not me.
The link I found is quite amazing and very informative. It is the best link I have ever come across and even if you don’t understand it all, you can get the gist of it. I am going to paste some of what is said on this link and then give you the link at the end. You will see suggested materials to read throughout these paragraphs and if you would like to know more, the links will react on the main link.
Various substances have been utilized for construction of a PVS—autologous, allograft, xenograft, or synthetic materials. The ideal material provides long-lasting suburethral support with minimal complications. Ideally, implanted material should be incorporated into the host with minimal tissue reaction. In reality, most materials promote organized fibrosis, reinforcing the sphincteric mechanism through improved suburethral support. Theoretically, a greater degree of fibrosis leads to better clinical results (Bidmead and Cardozo, 2000; Woodruff et al, 2008). Yet, inflammatory infiltration leads to rapid sling material degradation and possible tissue destruction with erosion (Bidmead and Cardozo, 2000). Although there is complete biocompatibility of the autologous sling and negligible urethral erosion, biologic and synthetic graft materials have been increasingly used to decrease operative time, morbidity, pain, and hospital stay (Niknejad et al, 2002). Outcomes of these materials are discussed later.
The most commonly used autologous materials include rectus fascia and fascia lata. Rectus fascia is harvested through a suprapubic Pfannenstiel incision. FitzGerald and associates (2000) reported that after sling placement, rectus fascial grafts undergo extensive remodeling with increased fibroblasts and connective tissue on biopsy specimens. Yet, histologic comparison of PVS grafts noted the greatest degree of host fibroblast infiltration and neovascularization in autologous materials with minimal inflammatory or foreign body reaction. The fascial graft changes were consistently intact with a small amount of sling degradation at explantation up to 65 months after placement (Woodruff et al, 2008). The rectus fascia harvest site may be scarred and thickened after prior operations, but this does not compromise its utility for PVS placement. The benefits of autologous tissue include the lack of tissue reaction and negligible urethral erosion (Webster and Gerridzen, 2003). Disadvantages include increased operative time and hospital stay, relative increase in postoperative pain, and suprapubic tissue seroma formation and hernia formation in a rectus fascial PVS (Gomelsky et al, 2003).
Fascia lata is the other commonly utilized autologous material for a PVS. It is harvested from the thigh and has similar properties to rectus fascia (Beck et al, 1988; Latini et al, 2004). Methods for harvest are discussed in the section on operative procedure. Like rectus fascia, fascia lata is completely biocompatibility and is associated with minimal tissue reaction. The recovery time may be less, and there is no risk of future abdominal hernia formation, unlike rectus fascia. Yet, fascia lata requires repositioning of the patient, increased operative time, and operating in an area unfamiliar to urologists (Govier et al, 1997). Wheatcroft and colleagues (1997) reported 67% of their patients had pain on walking for 1 week after surgery. Latini and coworkers (2004) only reported 7% of patients with pain at incision site 1 week postoperatively after using a Crawford fascial stripper. Debility from a thigh hernia has also been reported.
Another autologous material, vaginal wall, has also been used. Raz and associates (1989) described use of in-situ vaginal wall for autologous sling material. This tissue may lack sufficient tensile strength, and there is a risk of epithelial inclusion cyst formation and possible vaginal shortening. Lack of retropubic space dissection may militate against overall efficacy of this procedural variety (Raz et al, 1989; Ghoniem and Hassouna, 1998; Loughlin, 1998; Appell, 2000).
Biologic and synthetic graft materials have been increasingly used to decrease operative time, morbidity, pain, and hospital stay. Cadaveric allografts have been used in many nonurologic surgical arenas (e.g., orthopedics, neurosurgery) and eventually adopted for SUI. Allograft slings are currently derived from either cadaveric fascia lata or acellular human dermis. After harvest the allografts are processed by solvent dehydration or by lyophilization (freeze-drying) to remove genetic material and to prevent the transmission of infectious agents. Secondary sterilization may also be achieved by gamma radiation (Gomelsky et al, 2003). Histologic analysis reveals cadaveric dermis to have little host fibroblast infiltration and little neovascularity, particularly in central aspects of the graft. Additionally, inconsistencies were found within the materials grossly, with specimens exhibiting significant thinning and degradation of the graft, disrupting the sling scaffold (Woodruff et al, 2008). No specific allograft has shown a clinical advantage in use. Acellular dermis rehydrates in 0.9% saline quicker than does cadaveric fascia lata (5 minutes vs. 15 to 30 minutes), but each type is pliable, easy to use, and available in a variety of sizes (Gomelsky et al, 2003).
Biomechanical studies have shown that solvent-dehydrated cadaveric fascia lata and acellular dermis have a higher maximal load failure compared with freeze-dried cadaveric fascia lata (Hinton et al, 1992; Lemer et al, 1999). Lemer and associates (1999) prospectively studied the maximum load failure and stiffness of rectus fascia versus freeze-dried fascia versus solvent-dehydrated fascia and cadaveric dermal grafts. The mean values for maximum load to failure, maximum load-graft width, and stiffness were all significantly lower for the freeze-dried fascia lata group compared with the autologous, solvent-dehydrated, and dermal graft groups. The authors believed that ice crystal formation characteristics of tissue freezing may disrupt the collagen matrices, yielding poor strength properties. Dermal grafts differ from fascial allografts because they are derived from skin that is processed to eliminate the epidermis and all immunogenic cellular elements. Dermal grafts provide a protein matrix that serves as a collagen scaffold for the host’s own cellular matrix (Lemer et al, 1999).
Although biomaterials were thought to be a good choice for increased biocompatibility, lower risk of erosion, and lack of response to hormonal stimuli, allografts raise the concern of potential transfer of disease, including human immunodeficiency virus (HIV), hepatitis, and Creutzfeldt-Jacob prion infection. There has been one documented case of HIV transmission from a tissue transplant since the onset of screening in 1985. The estimated risk of acquiring tissue from a properly screened donor infected with HIV is 1 in 1,667,600 (Gallantine and Cespedes, 2002). A few cases of Creutzfeld-Jakob disease (CJD) have been reported after transplantation of cadaveric dura or corneas; however, skin obtained from animals infected with prions has demonstrated no detectable infectious particles. Currently, the theoretical risk of developing CJD from a non-neural allograft is 1 in 3.5 million. No cases of hepatitis or CJD have ever been attributed to the use of processed cadaveric fascia or dermis (Amundsen et al, 2000b; Gallantine and Cespedes, 2002). Within the musculoskeletal tissue transplantation literature, two cases of hepatitis transmission have been reported. The first refers to one tissue donor (cancellous chips) who transmitted HIV, hepatitis B virus, and human T-lymphotrophic virus. These transmissions all occurred before the implementation of extensive donor screening for viruses and bacteria or the availability of validate serologic tests (or both) (Shutkin, 1954). In June 2002, the Centers for Disease Control and Prevention (CDC) reported a case of hepatitis C transmission from minimally processed, cryopreserved patellar tendon allograft. Donor screening was performed during the window period for hepatitis C virus (HCV). Retest of the donor sample with HCV RNA testing confirmed the donor as the source once the recipient reported HCV infection 1 year after transplantation (CDC, 2003; Vangsness, 2006). Despite the low risk of disease transmission, human DNA has been detected in various allograft materials (Choe and Bell, 2001; Hathaway and Choe, 2002). The clinical significance of this is unknown. The theoretical risk of developing hepatitis from allograft graft material is unknown.
Xenograft Materials. This will be important to you if you are considering anything concerning animal tissue. It will cover both pig and cattle skin.
Xenografts have been utilized since the 1980s (Descurtins and Buchmann, 1982; Iosif, 1987) owing to their immediate accessibility and use without morbidity. Porcine and bovine xenografts have been used as sling material with decreasing popularity in recent years. The forms of xenograft available for use are porcine dermis or small intestinal submucosa (SIS) and bovine pericardium. Modern processing techniques using diisocyanate to remove genetic material have made porcine safer and more pliable, yet there is significant loss of tensile strength after implantation in a 12-week rabbit model (Dora et al, 2004). Histopathologic analysis has shown porcine SIS to contain growth factors that may reduce significant host-graft immunologic reaction and result in less tissue scarring (Wiedemann and Otto, 2004). Although a majority of data support SIS as nonimmunogenic, animal studies by Thiel and colleagues (2005) suggest that an intense inflammatory reaction 30 to 90 days after subcutaneous implantation occurs. In a report by Kalota (2004), 6 of 18 (33%) patients experienced postoperative inflammation after a PVS procedure. Konig and coworkers (2004) reported a single case of postoperative inflammation with abscess formation. Ho and colleagues (2004) reported a similar reaction in 6 of 10 patients. All of the patients presented with pain and erythema at the abdominal incision, and 2 developed abscesses. Five of the 6 patients with inflammatory responses are currently dry. All were treated conservatively, except 1 patient who required abscess drainage. The etiology is unknown but is likely due to a foreign body reaction from the multilayered (8-ply) SIS material, a reactive manufacturing ingredient, or a tendency for suprapubic fat to produce an inflammatory reaction (John et al, 2008). Kubricht and colleagues (2001) have shown that porcine SIS has less tensile strength than cadaveric fascia lata (Kubricht et al, 2001). Bovine pericardium is available in a preparation either cross-linked with glutaraldehyde or as a non–cross-linked acellular matrix (Gomelsky et al, 2003). Histopathologic comparison of sling materials revealed xenograft (porcine dermis) to have no host fibroblast infiltration, no inflammatory reaction, and no foreign body reaction. Xenograft had the highest propensity to encapsulate. A capsule formed around the porcine dermis, isolating the graft from the periurethral tissue. The graft was described as appearing similar to its original appearance at time of implantation (Woodruff et al, 2008).
Synthetic Materials. This is the type of sling most of us have complications from because it is widest used and the most manufactured and distributed.
In 1959, Francis Usher introduced the first synthetic biomaterial—polyethylene mesh—for use in hernia surgery. In the decades since there has been a transition to polypropylene and the introduction of additional synthetic materials (Amid, 1997). The first synthetic sling, made of nylon, was introduced in 1953 (Kraatz, 1953). The addition of synthetic material for use in PVS surgery brought obvious advantages: unlimited supply of artificial graft material in endless sizes and shapes, consistency in quality, and elimination of harvest site and decreased associated operative time. As compared with absorbable biomaterials, synthetic materials are more uniform, more consistent, and more durable. Additionally, artificial graft materials are sterile, biocompatible, noncarcinogenic, and free of biomaterials (Niknejad et al, 2002). On histopathologic comparison, synthetic materials demonstrated the greatest amount of fibroblast ingrowth and tissue ingrowth into the specimen. There is no degradation or disruption of the graft, and the mesh is completely infiltrated by the viable host tissue. Microscopically, the synthetic material has large amounts of fibroblasts and foreign body reaction characterized by giant cells and occasional microcalcification. This foreign body reaction is not visible grossly by graft disruption, and the graft was completely infiltrated by host tissue (Woodruff et al, 2008).
Artificial graft materials do have potential drawbacks, including graft infection, genitourinary erosion, or vaginal extrusion. The chemical and physical properties of each artificial material and patient characteristics determine how the sling is incorporated into the surrounding tissue and its susceptibility to infection, rejection, erosion, or extrusion. The susceptibility to infection in multifilament fibers is proportional to the porosity and the pore size of the materials (Amid, 1997; Niknejad et al, 2002). Tightly woven mesh provides a safe harbor for small bacteria, excluding macrophages and polymorphonuclear leukocytes. Loosely woven mesh allows tissue ingrowth and neovascularization, without limiting cellular access. Tissue bonding to the mesh strengthens and supports the repair. A tightly woven and large-diameter filament mesh will tend to exhibit increased stiffness or decreased pliability, contributing to migration, extrusion, or erosion. The classification by Amid (1997) used for synthetic materials in hernia surgery may be practically applied to urology as well (Table 73-1). The most frequently used materials are grouped into four types. Type I are totally macroporous prostheses (Atrium, Trelex, Marlex, Prolene) containing pores larger than 75 µm, which is the pore size for admission of macrophages, fibroblasts, blood vessels, and collagen fibers (White et al, 1981; Bobyn et al, 1982; White, 1988). Type II includes totally microporous prostheses (polytetrafluoroethylene [PTFE]: GORE-TEX, Surgical Membrane, and Dualmesh) containing pores less than 10 µm in at least one of their dimensions. Type III includes a macroporous prosthesis with multifilamentous or microporous components (PTFE: Teflon; braided Dacron mesh: Mersilene; braided polypropylene mesh: Surgipro; and perforate PTFE patch: MycroMesh). Lastly, type IV includes biomaterials with submicronic pore size (Silastic, Cellgard (polypropylene sheeting). Type IV is not appropriate for hernia surgery unless used in combination with type I (Amid, 1992). The most commonly utilized synthetic material for a PVS is polypropylene mesh (Table 73–2). It is composed of loosely woven strands of synthetic material, with a pore size greater than 80 µm, permitting passage of macrophages that may allow better host tissue ingrowth compared with the smoother, more tightly woven counterparts (Kobashi et al, 2005). This represents type I among the Amid classification. In fact, Amid (1997) concluded that the risk of infection and seroma formation was avoided by utilization of type I prostheses.
I understand writing this blog may not make me popular once again, but if we do not learn what may be put into our bodies and the complications they may cause us, we will be doomed to live with even more complications that can take away our lives. If you choose to bury your head, then that is your choice, but at least I am offering you information so that you can make the most important decision concerning your health either before you have anything done, or before you have reconstruction surgery.
As promised this is the link where all this is written. I hope it will help many out there so that they do not live in the same agony many of us live in now.