The medicolegal challenges of pelvic mesh usage
In this article, the first in our series of two on pelvic mesh and its medicolegal challenges, Dr Ivan Ramos-Galvez, Consultant in Pain Medicine and expert witness, explores the uses of pelvic mesh and the complications that can arise. The second in the series focuses on the physical and psychological effects pelvic mesh implants can have on claimants.
Both stress urinary incontinence (SUI) and pelvic organ prolapse (POP) arise due to weakness in the pelvic floor muscles. These common conditions affect millions of women and can have a huge impact on quality of life. The highest incidence is seen in post-menopausal women who have given birth several times, with factors such as obesity, smoking and connective tissue disorders further increasing the risk. Historically, these conditions were treated surgically by repairing the patient’s own tissues, either by inserting stitches or by using strips of nearby fascia to provide support. However, the failure rate of these techniques was high, at around 20%. Often, this was because the patient’s own tissue was not strong enough to provide a satisfactory repair. In order to overcome this problem, surgeons began to use mesh inserts to strengthen either the urethra or pelvic organs, for SUI and POP respectively.
The choice of material used for the mesh is extremely important. The pelvic floor undergoes significant movement and morphological changes during a woman’s lifetime, so the mesh must be strong enough to withstand stress and strain but flexible and elastic enough to permit movement. If the material is too stiff it may lose its shape and structure and possibly erode through the patient’s own tissues. The most commonly used material for these meshes is synthetic polypropylene (PPL) mesh, which is both chemically stable and non-biodegradable. PPL mesh also has a large enough pore size to allow infiltration by the host’s cells. This is thought to promote better tissue integration, leading to improved union and healing.
The use of pelvic mesh inserts quickly became standard practice, as they have several advantages over slings made from the patient’s own tissues. Their usage avoids the creation of a secondary harvesting site and shortens surgical time, and the results of the two procedures are comparable. Furthermore, pelvic mesh implants are cheap and readily available. However, in 2008 the US Food and Drug Administration (FDA) reported that they had received more than 1000 notifications of complications following the use of pelvic mesh in the previous three years. This has been confirmed over subsequent years. Adverse events include recurrence of SUI/POP, pain, infection and mesh erosion. Since their initial introduction, PPL meshes have been modified in an effort to reduce some of the side effects experienced by patients, but this has not totally alleviated the problems.
The incidence of mesh erosion varies widely, but, overall, it is thought to occur in around 10% of patients. A chronic inflammatory response to the implanted mesh leads to tissue breakdown, but it is unclear why this only occurs in some patients. Patient-related risk factors for mesh erosion include older age, oestrogen deficiency, prior surgical scarring, diabetes, steroid use and smoking. Product-related factors include the type and size of mesh used. Certain materials or designs are associated with higher rates of mesh erosion, as they may provide a focus for chronic infections. Complications can be reduced by minimising the length of the incisions and ensuring they are closed without any tension. Anchoring the mesh may also be beneficial, as it prevents subsequent puckering.
Infection may occur with or without mesh erosion being present. The risk of infection appears to be linked to the type of mesh material, the procedure used to insert it and the age and comorbidities of the patient. While monofilament PPL meshes are associated with the lowest rate of infection, scanning electron microscopy has revealed that all PPL implants show evidence of degradation after three months. Defects on the surface of the mesh may enable bacterial infections to proliferate, and degradation is further increased in the presence of an infection or chronic inflammation.
As the usage of mesh implants expanded rapidly, new products were made available on the market before full trial data became available. This situation arose partly because, up until 2016, the US FDA allowed new devices to be marketed if they could prove ‘substantial equivalence’ with an existing product. In the case of pelvic meshes, many products were compared to the ProteGen mesh sling, commonly used in hernia repair. However, it has now become clear that mesh-related complications are highly dependent on the anatomical placement of the mesh. In POP treatment, abdominal repairs have a much lower level of complications than those placed transvaginally. Therefore, equivalence in performance cannot be assumed for the same mesh implanted in different areas of the body. Recent NICE guidelines echo this, recommending that transvaginal mesh repair should only be performed for research purposes, while mesh repair for SUI may still be offered.
Since their introduction, sub-urethral sling procedures using synthetic meshes have become the gold standard for the treatment of SUI and are increasingly used in cases of POP. However, these implants are not without their issues. Many women have been left with complications so severe that the effect on their quality of life has been significant. Not surprisingly, this has led to huge lawsuits against both manufacturers and individual surgeons. However, the use of pelvic mesh implants may still be indicated in some cases, particularly those involving SUI, but the risks and benefits need to be carefully considered and discussed between surgeon and patient.
About Dr Ramos-Galvez
Dr Ivan Ramos-Galvez‘, Consultant in Pain Medicine, current NHS practice is at the Royal Berkshire Hospital with a private practice at Spire Dunedin and Circle Hospitals in Reading.
After extensive training in spinal surgery at the Oxford Deanery, he undertook further specialisation in pain medicine. His understanding of the interactions between these complex areas of medicine means he is often called upon to provide an opinion within his clinical practice or as an expert witness where spinal surgery has led to complications.
His range of expertise with regards pain is widespread and his particular areas of expertise include, but are not limited to:
- Complex Regional Pain Syndrome (CRPS)
- Fibromyalgia
- Spinal Pain
- Chronic and chronic widespread pain
- Chronic Pain Syndromes
- Neuropathic pain
- Pelvic Mesh Pain
- Phantom limb pain and Post Mastectomy Pain Syndrome
- Multi-disciplinary pain management
Dr Ramos-Galvez has developed close links into several other specialisms including spinal surgery and cancer/palliative care and is frequently called upon to treat patients when conventional methods of pain relief have failed.
Further reading:
Mironska, E., Chapple, C., & MacNeil, S. (2019). Recent advances in pelvic floor repair. F1000Research, 8, F1000 Faculty Rev-778. https://doi.org/10.12688/f1000research.15046.1
Shah, H. N., & Badlani, G. H. (2012). Mesh complications in female pelvic floor reconstructive surgery and their management: A systematic review. Indian journal of urology: IJU: journal of the Urological Society of India, 28(2), 129–153. https://doi.org/10.4103/0970-1591.98453
