A general introduction to employment of utilities of meshes as surgical implant. Relevant biomaterial engineering basis are highlighted in context of current limitations of mesh-tissue integration and areas of ongoing translational scientific research.

1. Discuss Use of Mesh in
Surgery
By Dr Echebiri, P.
Department of Surgery, National Hospital, Abuja
Supervisor: DR BADEJO
7th May, 2018

2. OUTLINE
• Introduction
• Classification
• Qualities of ideal mesh
• Mechanism of mesh integration into the tissues
• Parameters of mesh
• Generations of mesh
• General principles guiding use

3. OUTLINE• Broad indications
• Contraindications
• Applications of mesh in Surgery
• Complications
• Current trends/future perspectives
• Local experience
• Conclusion
• References

4. INTRODUCTION
• Definition:A fabric-like surgical implant.
• Surgical implants are exogenous materials that are embedded within tissues of a patient in
order to supplement structural deficiencies thereby enhancing desired function.
• BRIEF HISTORY
• Surgical meshes, were driven by need for longlasting repair of hernias.

5. INTRODUCTION

6. INTRODUCTION
• In 1890,Theodor Billroth suggested that the ideal way to repair hernias was to
use a prosthesis.
• In 1955, Dr. Francis Usher studied and experimented with Nylon, Orlon, Dacron
andTeflon
• Two years later, Usher started to develop a woven marlex mesh which is a
polyethylene
• Subsequently, in 1958, Usher published his surgical technique using a
polypropylene mesh

7. INTRODUCTION
• 30 years later the Lichtenstein repair was popularized for hernia repair by Dr
irving Lichtentenstein using marlex meshes for open inguinal hernioplasty
• In 2002, the European Union HerniaTrialists Collaboration concluded that
the use of surgical meshes was superior to other techniques.
• At present, many surgeons affirm that use of a mesh is the preferred way to
repair hernias.

8. CLASSIFICATION
• All implants including mesh are FDA class 3 medical devices implying stringent
regulatory control because they sustain or support life
• Meshes may be classified in various ways:
• Temporary e.g polyglactin, polyglycolic acid OR Permanent e.g of polypropylene
(PP), polytetrafluoroethylene (PTFE)
• Absorbable e.g polyglactin, polyglycolic acid OR Non-absorbable e.g PP, PTFE

9. CLASSIFICATION
• Synthetic e.g polytetrafluoroethylene, polyglactin OR Biologics e.g porcine
dermis, bovine dermis, cadaveric human dermis
• Flat e.g Kugel patch OR Pre-formed e.g Gilbert plug-and-patch, Prolene hernia
system
• Polymers OR Metals OR Composites.The major polymers include
Polypropylene, Polytetrafluoroethylene and Polyester.Titanium is the metal
mesh commonly used. Composites comprise layers of different materials e.g
Parietex (polyester+collagen), C-Qur (polypropylene+omega-3)

10. CLASSIFICATION

11. CLASSIFICATION

12. CLASSIFICATION
• Based on porosity: Proposed by Amid (1997)
Type 1- Macroporous >75microns e.g macroporous polypropylene
Type 2- Macroporous with microporous portions
Type 3- Microporous < 10 microns e.g polytetrafluoroethylene
Type 4- Submicronic pore/sheets e.g biologics such as human alloderm
• Influences biocompatibility

13. CLASSIFICATION

14. CLASSIFICATION

15. CLASSIFICATION

16. QUALITIES OF IDEAL MESH
Cumberland (1952) and Scales (1953) set out eight criteria for an ideal surgical mesh as
follows:
• Non-carcinogenic
• Chemically inert
• Resistant to mechanical strain
• Suitable for sterilization
• Biologically inert

17. QUALITIES OF IDEAL MESH
• Non-allergenic
• Limited foreign body tissue reaction
• Amenable to production in useful form for surgery

18. MECHANISM OF MESH INTEGRATION INTO
THETISSUES
• The introduction of a foreign material into the body triggers a healing
response characterized by one of three stereotypical reactions:
Destruction or lysis
Inclusion or tolerance, and
Rejection or removal.
• The healing response begins with inflammation which is characterized in 4
phases

19. MECHANISM OF MESH INTEGRATION INTO
THETISSUES
Phase I
• The mesh adsorbs proteins and the surface becomes coated with coagulum
composed of albumin, complement factors, immunoglobulins, fibrinogen
and plasminogen
• Platelets adhere to this coagulum and degranulate, secreting a host of
chemokines that further attract platelets, neutrophils, monocytes
fibroblasts, and smooth muscle cells to the site in a sequence of waves

20. MECHANISM OF MESH INTEGRATION INTO
THETISSUES• Neutrophils are unable to degrade the mesh, and subsequently undergo
apoptosis
Phase II
• Monocytes reach the site and differentiate into macrophages which
demolish necrotic debris, but fail to destroy the mesh.
Phase III
• Macrophages then coalesce into foreign body giant cells in the presence of
the persisting prosthesis that reside there indefinitely

21. MECHANISM OF MESH INTEGRATION INTO
THETISSUES

22. MECHANISM OF MESH INTEGRATION INTO
THETISSUES
Phase IV
• Fibroblasts begin migrating into the mesh by 2nd -5th day
• The entrapped fibroblasts and smooth muscle cells are induced to
continually deposit collagen fibrils and extracellular matrix components
within the extracellular space
• The foreign body reaction is a complex defence mechanism driven by the
foreign body giant cells, fibroblasts and blood vessels

23. MECHANISM OF MESH INTEGRATION INTO
THETISSUES
• Matrix metalloproteinases (MMPs) then function to alter the orientation,
structure, and proportion of the different collagen fibrils to increase the
type I:III collagen ratio and produce parallel bundles of collagen
• With remodeling, the overall strength of this collagen improves over a
period of about 6 months resulting in a relatively less elastic tissue with
about 70-80% of the strength of the native connective tissue

24. MECHANISM OF MESH INTEGRATION INTO
THETISSUES
• Healing in the presence of mesh therefore occurs predominantly by fibrosis
leading to scar formation with little or no regeneration of tissues.
• Mesh inclusion/integration requires regenerative tissue healing. Conversely
excessive fibrosis is associated with complications such as mesh
contraction, adhesion formation, infection, fistula etc

25. MECHANISM OF MESH INTEGRATION INTO
THETISSUES

26. MECHANISM OF MESH INTEGRATION INTO
THETISSUES
• The degree of fibrosis in mesh implants depends on material chemistry,
structure (size, shape, mechanical properties), surface topography (porosity,
roughness) in addition to:
Tissue variables including anatomic site, blood supply
Pathology variables including infection, underlying co-morbidities

27. PARAMETERS OF A MESH
• Tensile strength: Maximum stress that it can withstand without tearing or
breaking. Intra-abdominal pressure peaks in a healthy adult occurs during
coughing or jumping and is estimated to be about 170 mmHg. Hence, the
mesh used to repair abdominal hernias must withstand at least 180 mmHg
before failing.

28. PARAMETERS OF A MESH
• Elasticity: Ability to regain original shape and size after deformation.
Studies based on human abdominal walls show that at the maximum tensile
strength of 16 N/cm, it undergoes a mean distension of 23% ± 7% and 15% ±
5% in males when stretched in vertical and horizontal directions,
respectively. In females, a distension of 32% ± 17% and 17% ± 5% with
vertical and horizontal stretching has been observed. Recurrences may
therefore occur at the margins of poorly elastic meshes.

29. PARAMETERS OF A MESH
• Pore size: Large pores facilitate easier infiltration of immunocompetent cells,
providing protection from infection as well as fibroblasts leading to better mesh
integration. Scar tissue rapidly bridges microporous meshes resulting in
minimum integration and higher rejection rates.
• Weight/density: Meshes may be categorized as heavy-weight, when they are
above 80 g/m2 ; medium weight, between 50 and 80 g/m2 ; light-weight,
between 35 and 50 g/m2 ; and ultra-lightweight, below 35 g/m2. In general,
lighter weight meshes elicit less pronounced foreign body reaction, hence
better tissue incorporation

30. PARAMETERS OF A MESH

31. PARAMETERS OF A MESH
• Constitution: Meshes could be fabricated as monofilament or multi-
filaments. Monofilaments possess greater reinforcement ability, but with
stiffness and limited pliability. On the other hand, multi-filaments are soft
and pliable but are able to harbor bacteria in their crevices so increasing
erosion rates by 20–30%

32. PARAMETERS OF A MESH
• Material absorption: Non-absorbable meshes have better tensile strength,
are easy to shape intraoperatively and have long-term stability. However,
they are frequently associated with complications such as mesh stiffness
over time, hernia recurrence, mesh erosion, and adhesions. Absorbable
meshes were designed to reduce these long-term complications.They
enhance fibroblast activity. Unfortunately, after prosthesis absorption, the
scar tissue left behind is not as strong enough alonepredisposing to hernia
recurrence.

33. PARAMETERS OF A MESH
• Shrinkage:This is estimated at about 40% after implantation. In reality, it
results from active compression of mesh by scarring tissues. Shrinkage
predisposes to pain, and recurrence. Hence, hernia surgery requires
adequate mesh overlap.
• Isotropy:The potential of synthetic meshes, to exhibit a difference in
material properties e.g., elasticity in different material axes. Indiscriminate
orientation of anisotropic mesh may adversely affect hernia repairs.

34. GENERATIONS OF MESH
• No mesh is ideal hence a large variety of commercially available mesh for
use.
• They are grouped into three generations.
• First generation meshes: Synthetic non-absorbable prosthesis e.g Marlex
(BARD), Prolene (Ethicon),Trelex (Meadox)
• Second generation meshes: Composite prosthesis e.g Proceed (Ethicon),
Ultrapro (Ethicon),Ti-Mesh (GfE)

35. GENERATIONS OF MESH
• Third generation meshes: Biological prosthesis e.g Surgisis (Cook), AlloMax
(Davol), Permacol (Covidien)

36. GENERAL PRINCIPLES GUIDING USE
• Pre-Operatively:
Appropriate indication
Obtain consent
Selection of mesh
• Intra-Operatively:
Strict asepstic techniques
Antibiotic prophylaxis

37. GENERAL PRINCIPLES GUIDING USE
Optimum exposure of site of interest
Meticulous hemostasis
Gentle tissue handling
Ensure well-vascularized implantation site
Modify size and shape to fit
Adequate overlap of defect
Secure fixation

38. GENERAL PRINCIPLES GUIDING USE
Tensionless mesh placement
Adequate soft tissue cover/avoid exposure

39. BROAD INDICATIONS
• Reconstruction e.g abdominal wall defect, chest wall defect
• Augmentation e.g hernioplasty, splenorrhaphy, duroplasty
• Fixation/ stabilization e.g rectal prolapse, arthroplasty
• Replacement e.g skin subsitutes, endovascular bypass grafts

40. CONTRAINDICATIONS
• Infected field
• Necrotic tissues
• Inadvertent enterotomy
• Concurrent procedures that may jeopardise sterility of mesh
• Inadequate hemostasis
• Avascular/ischemic bed
• Inadequate soft tissue cover
• Children
• Pregnant women/ Child-bearing age

41. APPLICATIONS OF MESH IN SURGERY
General surgery
• It is currently considered the preferred method of hernia repair
• Employed in open anterior repairs e.g Lichtenstein hernioplasty, open
posterior repairs e.g Rives-Stoppa giant prosthetic repair of visceral
sac(GPRVS) and in endoscopic/laparoscopic techniques likeTAPP,TEP and
IPOM
• Hernia recurrence is markedly diminished

42. APPLICATIONS OF MESH IN SURGERY

43. APPLICATIONS OF MESH IN SURGERY• Indications for mesh in hernia repair:
Large hernia defects > 4cm
Recurrent hernias
Incisional hernias
Elderly patients
Multiple hernias (swiss cheese defects)
Hernias abutting/close to bony structures e.g costal margins

44. APPLICATIONS OF MESH IN SURGERY

45. APPLICATIONS OF MESH IN SURGERY
Significant loss of abdominal domain
Obese patients
Ascites
Connective tissue disorders e.g Marfan, Ehlers-Danlos
Need for early return to strenuous activities e.g athletes, security
personnels
Laparosopic/endoscopic repairs

46. APPLICATIONS OF MESH IN SURGERY
• Reconstruction of abdominal wall defects following wide excision of
extensively infiltrating tumours
• Treatment of acute abdominal wound failure (burst abdomen) e.g
polyglactin mesh
• Approximation of fascia in the patient with abdominal catastrophe
necessitating open abdomen management
• Hemostastic wrap in splenic conservation/partial splenorrhaphy

47. APPLICATIONS OF MESH IN SURGERY

48. APPLICATIONS OF MESH IN SURGERY
• In gastrointestinal transplant surgeries to achieve sufficient abdominal
closure due to loss of domain and multiple previous scars leading to
contracture
• Treatment of rectal prolapse e.g Ripstein, Well’s,Thiersch procedures
• Protection of small bowel against radiation enteropathy in patients for
pelvic irradiation by means of absorbable mesh slings to suspend bowels
above the pelvis

49. APPLICATIONS OF MESH IN SURGERY
Cardiothoracic and vascular surgeries
• Chest wall reconstruction following resection of sternal/rib tumours e.g
Gore-Tex
• Repair of traumatic hernia defects
• Hiatal hernia repairs to reinforce crural closure especially in paraesophageal
hernias
• As endovascular grafts e.g femoropopliteal bypass

50. APPLICATIONS OF MESH IN SURGERY

51. APPLICATIONS OF MESH IN SURGERY
Orthopedics
• For augmentation of tendon repairs e.g acute quadriceps tendon rupture
• In arthroplasties to wrap uncemented implants to encourage bone ingrowth
• To maintain the relative positions of engrafted bone tissues as well as bone
fragments from comminuted fractures

52. APPLICATIONS OF MESH IN SURGERY
Plastic Surgery
• As skin subsitutes to provide dermal tissue scaffold for epidermal growth
e.g biobrane
Urology
In urogynecological procedures for treatment of stress urinary incontinence
e.g Tensionless vaginal-type (TVT) slings

53. APPLICATIONS OF MESH IN SURGERY

54. APPLICATIONS OF MESH IN SURGERY
Neurosurgery
• As dural substitute in duroplasty e.g for management of cerebrospinal fluid
(CSF) leak following excision of posterior fossa tumours
• Cranioplasties and vertebroplasties using titanium mesh

55. APPLICATIONS OF MESH IN SURGERY

56. COMPLICATIONS
• Meshoma formation
• Chronic pain
• Infection
• Extrusion
• Erosion
• Adhesion
• Bowel obstruction
• Failure
• Recurrence of hernia

57. COMPLICATIONS

58. COMPLICATIONS

59. COMPLICATIONS

60. COMPLICATIONS

61. COMPLICATIONS

62. COMPLICATIONS

63. CURRENTTRENDS/FUTURE PERSPECTIVES
• Mosquito nets as substitutes in resource-constrained settings
• Non-mesh prosthesis e.g Desarda
• Controversies: Banning in Europe, Litigations in America
• Drug-eluting meshes e.g antibiotic-impregnated, Gore-Tex dual mesh with
chlorhexidine+silver

64. CURRENTTRENDS/FUTURE PERSPECTIVES
• Biocompatible and biodegradable natural and synthetic polymer coatings
• Nanofiber systems
• Mesh Nanoelectronics: Seamless Integration of Electronics withTissues e.g
3D neural tissue to be precisely delivered to targeted brain regions in a
minimally invasive manner.

65. LOCAL EXPERIENCE
• 2004-2017: 517 hernia open hernia repairs done of which 233 indicates use of
mesh
• Data is not representative due to limitation of details in the entries in the
registers and lack of a searchable electronic record keeping system.

66. CONCLUSION
• Meshes have found a critically useful niche in surgery, although it is by no
means an optimum implant due to its potentially severe drawbacks
• Refinements are in progress to improve biocompatibility, so that a mesh
that can be effectively incorporated with minimal inflammation and/or
infection.

67. THANKS ALL

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74. THANKS