hernial meshes and prostheses

1. HERNIAL PROSTHESES
MODERATORS -
PROF DR H K BHATTACHARYA
PROF DR R K DEKA
PROF DR A AHMED
PRESENTED BY –
DR AYMEN AHMAD KHAN

2. WHAT IS HERNIA
 Hernia is derived from the Latin word for rupture.
 A hernia is defined as an abnormal protrusion of a part or whole of the
viscus through the wall of its containing cavity
 Its content may be any abdominal viscera, most frequently the small bowel
and omentum.
 When protruding through the hernial ring, the herniated structure is
covered by the parietal peritoneum, here called hernial sac.
 Although hernias can occur in various regions of the body, the most common
site is the abdominal wall, particularly in the inguinal and ventral regions

3. Mainly places of abdominal wall hernia:
Epigastric (E); Umbilical (U); Hypogastric
(H); Inguinal (I).
Hernias of the groin area: Indirect (I); Direct (D); Femoral
(F).

4. Schematic drawing of a hernia. In this case, the bowel
is the herniated viscera.
Schematic drawing of a normal abdominal wall and
their layers: Skin (S); Fat Tissue (F); Aponeurosis
(A); Pre-peritoneal Fat Tissue (F); Peritoneun (P);
and the abdominal viscera (V).

5. TREATMENT OPTIONS FOR HERNIA
 merely correcting the hernia defect with sutures does not avoid
the source of the problem, because the patient’s tissues will
still be fragile and predisposed to rupturing again at the same
site. The recurrence rate for ventral hernia may be as high as
40–54% after open repair without meshes
 Mesh repair is superior to suture repair, results in a lower
recurrence rate and less abdominal pain.
 For each type of hernia there are several techniques
involving prostheses and different models of prosthesis.

6.  To help the surgeon choose, it is helpful to look at the prosthetic
landscape with a perspective based on
(1) the prosthetic’s raw material and design,
(2) the implantation technique
(3) the clinical scenario
 For treating inguinal hernia, the use of a polypropylene prosthesis is
the best technique.
 Endoscopic inguinal hernia techniques result in a lower incidence of
wound infection, hematoma formation and an earlier return to
normal activities or work than the Lichtenstein technique. When
only considering chronic pain, endoscopic surgery is superior to open
mesh.
 However, endoscopic inguinal hernia techniques need general
anesthesia, result in a longer operation time and a higher incidence
of seroma than the Lichtenstein technique

7.  For fixation of the mesh in ventral hernia repair, most authors have
used sub-lay technique. Which can be extraperitoneal and
intraperitoneal.
 In sub lay technique the mesh is sutured into place on the posterior
rectus sheath with approximately 4 cm of fascia overlap


8.  The other two repair options include an inlay technique such that the
mesh is sutured to the fascial edges, and an onlay technique whereby
the mesh is placed and sutured onto the anterior rectus sheath
 The inlay technique has the advantage of minimal soft-tissue dissection
thus reducing devascularized tissue, but the disadvantage of high rate
of recurrences, while the onlay technique has the disadvantage of vast
soft tissue dissection above the rectus layer.
Inlay Onlay

9. INTRODUCTION
 An abdominal wall hernia may be repaired by closing the hernia defect under
tension with sutures or its reinforcement with mesh.
 The suture repair is characterized by high recurrence rates.
 Mesh repair is superior to suture repair, results in a lower recurrence rate
and less abdominal pain.
 Mesh helps to replace the deficient tissue and reinforce weak tissue
 It provide the surgeon with the ability to achieve a durable, tension free
repair.

10. IDEAL HERNIAL PROSTHESIS
 Should be strong but pliable and easy to handle.
 Should be inert, non allergic , non biodegradable and non carcinogenic
 Should have optimum thickness ( since density determines tissue reaction)
 Should stimulate adequate fibroblastic activity and gets rapidly incorporated
into the tissues.
 Should achieve early, rapid and optimum ingrowth of fibrocollagenous tissue
to prevent migration or dislocation.
 Should preferable be macroporous, monofilament, transparent and resist
infection
 Should provide barrier to adhesions in intra abdominal placements.
 So far no single mesh fulfils all the criteria.

11. PHYSIOLOGICAL RECONSTRUCTION
 Mesh implants provides bio mechanical strength to attenuated fascial tissue.
 It is designed to withstand the tension forces acting on the abdominal wall.
 Mesh does not imepede but actually facilitate the healing process of the
hernia defect by encouraging ingrowth of body’s own connective tissue by
induction of strong collagen tissue around mesh.
 Large pore size mesh offers advantage over traditional small pore mesh, is
that tissue is able to grow through the large pores of the mesh and create a
thinner more integrated scar . Thus ultimately creates a more “ Elastic Scar”

12. TYPES OF PROSTHESES
Commoly used prostheses for repair of hernia are
1: Polypropylene
2: Polyester
3: PTFE (polytetrafluroethylene)

13. POLYPROPYLENE MESH
 It is most widely used because of its stability, strength, inertness and handling qualities.
 The mesh is made of prolene fibers arrange in a network with pores of different sizes
 The product differs with different manufactures regarding size of monofilament material, size of
pores, its thickness , pliability and shrinkage
 Initially fibers were woven but later changed to knitted construction to prevent unravelling of
cut edges of the mesh.
 Monofilament is preferred as it is less likely to give infection.
 All implanted meshes showed an increased stiffness of abdominal wall. Light weighted meshes
results in less restriction of abdominal wall compliance while providing more adequate strength
for repair of ventral hernia.
 Example are- Marlex , PROLENE soft and surgipro

14.  PHS ( prolene hernial system ) and a plug. It is indicated for open technique for groin,
epigastric and umbilical hernia.
 Plug is implanted in deep inguinal ring.
 PHS has 3 parts-
1. underlay
2. connector
3. onlay

15. POLYESTER
 They are not very popular with laparoscopic surgeons though
they are widely used in FRANCE
 They are mainly used for Stoppa Technique
 The Stoppa Repair is a tension free type of hernia repair. It is
performed by wrapping the lower part of the parietal
peritoneum with prosthetic mesh and placing it at a
preperitoneal level over myopectineal orifice. It was first
described in 1975 by Rene Stoppa. This operation is also
known as giant prosthetic reinforcement of the visceral sac
(GPRVS).

16.  The MPO is simply a layer of non-muscular Connective Tissue called
"Transversalis Fascia", consisting of two thin and adherent semi-layers.
The MPO is bordered:
1. Above by the arching fibers of the internal oblique and transversus
abdominus Muscles
2. Medially (towards the center or to the right) by the Rectus Abdominus
Muscle and its fascial Rectus Sheath
3. Inferiorly by Coopers Ligament, and
4. Laterally by the Ileopsoas Muscle

17. Myopectineal Orifice of Fruchaud (MPO)

18. POLYTETRAFLUROETHYLENE MESH
( PTFE )
 They are soft , smooth and strong.
 They are suitable for repair of all groin and ventral
hernias by open as well as laparoscopic technique.
 They are avoided for intraabdominal placements as
there are reports of complication of bowel
adhesions, obstruction , fistulisation and erosion
into abdominal visceras.

19. COMPOSITE MESHES
1. Light weight composite meshes without adhesion
prevention barrier
2. New composite meshes with adhesion prevention
barrier ---
a> Absorbable barrier composite mesh
b> Non absorbable barrier composite mesh

20. Lightweight Composite Meshes Without
Adhesion Prevention Barrier
 When polypropylene material is reduced in the mesh , its handling become
difficult. The handling is improved by incorporating absorbable filaments of
polyglactin 910 ( Vicryl ) or poliglecaprone (Monocryl )
 These filaments are twisted together and then knitted to form a requisite
mesh structure
 They are partially absorbable since they have 50 percent Vicrly or Monocryl
 They are macroporous , this induce better tissue ingrowth of strong three
dimensional collagen fiber network.
 The construction results in almost 70% reduction of implanted foreign body
and results in “ scar mesh “
 Bio compatibility of mesh increase with low density, low weight , large pore
size and mono filament construction.

22. New Composite Meshes With Adhesion
Prevention Barrier
 They are used in intra peritoneal placement of mesh. Therefore requires a
material which has both high tissue ingrowth towards abdominal wall and non
adhesiveness on other side to prevent bowel adhesions.
 In these meshes layer facing abdominal cavity prevents adhesions with bowel
by allowing the formation of neo peritoneum, while layer in contact with
abdominal wall encourages high tissue in growth
 They are of 2 types -
a> absorbable barrier composite mesh
b> non absorbable barrier composite mesh

23. Absorbable Barrier Composite Mesh
1: Sepramesh
 Composed of macroporus polypropylene on one side with bioresorbable , non
immunogenic membrane of sodium hyluronate and carboxymethylcellulose on
other side
 Macroporus polypropylene layer in contact with abdominal wall encourages
high tissue in growth.
 The absorbable barrier turns to gel in 48 hrs, remains for approx. 7 days and
is cleared from body in 28 days. This anti adhesive material forms a physical
barrier on damaged surfaces to prevent adherence.
 Sodium hyaluronate and carboxy methylcellulose are anionic polysaccharides
that form a membrane that is negative charged which promotes the
separation of healing tissues

24. 2: Parietex Composite :
 Composed of multifilament polyester mesh with purified, oxidised bovine atelocollegen
type 1 coating covered by an absorbable , anti adhesion film of polyethylene glycol and
glycerol
 Polyethylene glycol is hydrogel that decreases tissue adherence and glycol is hydrophobic
lipid. They form a membrane to prevent bowel adhesions.
 The collagen, polyethylene glycol and glycerol film is resorbed in approx. 3 wks
3 : Parientene composite :
 It consists of same antiadhesive barrier but coated to polypropylene

25. 4: Proceed surgical mesh
 It is laminated mesh composed of oxidised regenerated
cellulose ( ORC ) fabric, prolene soft mesh , a non absorbabale
polypropylene mesh which is encapsulated by polydioxanone
polymer.
 The polypropylene mesh allows for tissue ingrowth while ORC
side provides a bioresorbable layer that physically separates
the polypropylene mesh from abdominal viscera during wound
healing period to minimize tissue attachment to mesh.

26.  Polydioxanone provides a bond to ORC layer.
 It leaves behind less residual foreign body, and does not harbour bacteria

27. Non absorbable barrier composite mesh
A> Bard Composix Mesh :
 Consists of sheet of Marlex with thin layer of ePTFE on one surface.
 The PPM side is attached to the abdominal wall and the ePTFE surface will
contact the bowel.
 It provide good tissue incorporation on PPM surface while diminishing the
chances of abstruction and fistulisation.
B> GORE – TEX Dual mesh :
 Has 2 surfaces : one is very smooth ( microporous 3mm) and other side is rough
( micropores 22mm)
 It is implanted with smooth surface against visceral organs and rough surface
against ehich tissue incorporation is desired

28. Mechanism Of Biomaterial Integration
To The Organism
A> Normal healing
 After tissue injury, such as surgery, the healing process
occurs. It takes place in three phases :
 Inflammatory, substrate or exudative phase,
characterized firstly by vasoconstriction and platelet
aggregation. Fibrin is formed as the coagulation
mechanism continues, in order to diminish loss to
hemorrhage, and it lasts approximately 15 minutes.
 The cell response is processed 6 to 16 h after the onset of
the lesion, when a large amount of polymorphonuclear
neutrophils appear, as the first wave of cell migration.
They stay from 3 to 5 days, with a peak within 68 h .
These are macrophage precursors.

29.  Neocapillary growth and fibroblastic proliferation
begin about 36 h after injury. The activated
macrophages are the predominant leukocytes on day
3, when they peak and persist until healing is
complete. This first phase lasts until the 2nd day ,
and may last until the 4th day postoperatively .
 Around the 3rd to 5th day the proliferative or
connective tissue phase begins. in which
angiogenesis and fibroplasia occur, from the
proliferation of the endothelial cells and fibroblasts,
respectively. They will build the granulation tissue.
The lymphocytes appear around the 5th day,
peaking on the 7th day , and they are mostly
represented by T Lymphocytes.

30.  During the 2nd week, the fibroblasts become the dominant
cells, especially on the 10th day. After this period they
differentiate into fibrocytes. Fibroblasts synthetize
collagen, which promotes repair resistance.
 The fibroblasts migrate into the wound from the
surrounding tissue, differentiating into myofibroblasts,
forming actin filaments, synthetizing a collagen .
 Wound contraction is an essential aspect of healing. It
diminishes the area of the defect making it easier to close

31.  From the 21st day onwards, during the last phase of
the healing process, called molding, maturing,
resolutive or differentiation phase, tension
resistance will reach its highest levels. The
accumulation of collagen tissue peaks on the 21st
day, and its value remains practically constant in the
3 following months.
 In the mature matrix type I is 80% to 90%, and type
III is 10 to 20% of the total collagen. This matrix
undergoes continuous modification until a stable
matrix is formed. The scar tissue takes on 40% of the
tensile resistance around 6 weeks, 80% around 6
months, and its maximum resistance is achieved after
many months, or even years, but it is not equal to the
resistance of healthy tissue

32. B> Healing With A Prosthesis
 Immediately after implantation, the prosthetic adsorbs proteins
that create a coagulum around it. This coagulum consists of
albumin, fibrinogen, plasminogen, complement factors, and
immunoglobulins.
 Platelets adhere to this protein coagulum and release a host of
chemoattractants that invite other platelets,
polymorphonucleocytes (PMNs), fibroblasts, smooth muscle
cells, and macrophages to the area in a variety of sequences.
 The presence of a prosthetic within a wound allows the
sequestration of necrotic debris, slime-producing bacteria,
and a generalized prolongation of the inflammatory response of
platelets and PMNs

33.  Macrophages then increasingly populate the area to
consume foreign bodies as well as dead organisms and
tissue. These cells ultimately coalesce into foreign body
giant cells that stay in the area for an indefinite period of
time.
 The fibroblasts and smooth muscle cells subsequently
secrete monomeric fibers that polymerize into the
helical structure of collagen deposited in the
extracellular space.
 The overall strength of this new collagen gradually
increases for about 6 months, resulting in a relatively
less elastic tissue that has only 70% to 80% of the strength
of the native connective tissue

34. Biological mesh
 When should a biological mesh should used instead of synthetic
mesh?
 Biological mesh are used when synthetic mesh are contraindicated as
synthetic materials do not support vascular ingrowth and are
susceptible to infections.
 Biological mesh supports angiogenesis into collagen matrix , so
delivery of WBCs and antibiotics are possible. The collagen
scaffolding supports native fibrobast ingrowth and collagen
deposition.
 Later scaffolding is completely degraded , eventually allowing for
bacterial removal.

35. Biomesh Type Products, Manufacturers
Human acellular dermis AlloDermЁ
, LifeCell
Flex HDTM
, J&J
AlloMaxTM
, Davol
Xenogenic acellular dermis PermacolTM
(porcine), Tissue Science Laboratories
SurgiMendTM
(bovine,calf), TEI Biosciences
CollaMendTM
, (porcine) Davol
XenMatriXЁ
(porcine), Brennen Medical LLC;
Brennenmed.com
StratticeTM
, LifeCell
Porcine small intestine
submucosa
SurgisisЁ
, Cook Medical
FortaGenЁ
, Organogenesis

36. LifeCell Alloderm
 AlloDerm®
 Cadaveric tissue
 Limited sizes
 High cost
 Well established
 Not regulated by FDA as a medical device
 Claims are extreme
 Migration from other surgical areas was natural

37. FortaGen Organogenesis
 Porcine derived tissue : crosslinked collagen
 Begin to infiltrate with cells by 30 days post-implant
 Are substantially remodeled by 6 months
 Are well-integrated at the suture line (provides a lasting graft-host tissue
interface not dependent on permanent sutures)
 Do not elicit a foreign body response
 Are as strong as adjacent host tissue at 360 days
 Do not re-herniate

38. Fixation Of Mesh
 For intra abdominal placement of mesh , few strong sutures
should be placed at least at 4 corners of the mesh.
 Tackers should not protrude too much beyond the mesh as
these can cause adhesion to a bowel loop. Trackers
penetrate only 2mm beyond the mesh and do not provide
same holding strength as sutures. Tensile strength of sutures
is 2.5 times greater than tackers
 Full thickness abdominal wall suture fixation is necessary to
prevent migration of mesh.
 Tackers fixes the mesh to the peritoneum only and not
directly to the fascia.

39. DOUBLE CROWN TECHNIQUE : tackers are initially placed 1
cm apart at edge of the mesh and a second inner crown of
tackers is placed 1 cm apart at the edge of the defect.
Abdominal wall is pressed down when tackers are applied.

40. Complications
 PAIN : fixation of mesh with sutures by laparoscopic technique for ventral or
incisional hernia repair can be painful initially. Pain resolves over time.
 SEROMA : most commonly occurrence and resolve over a period of time.
 URINARY BLADDER INJURY
 BOWEL ADHESIONS
 BOWEL OBSTRUCTIONS
 BOWEL FISTULIZATION
 EROSION INTO INTRA ABDOMINAL ORGANS
 MIGRATION OF THE MESH
 RECURRENCES

41. SUMMARY
 Polypropylene mesh preferably light weight composite mesh
should be ideal for open groin hernias, small ventral hernia
and for TAPP and TEP.
 Prosthesis with either an absorbable or a non absorbable
barrier are used for intra abdominal placements as they
prevents bowel adhesions.
 Mesh should be of proper size to compensate for shrinkage
 Mesh should be properly fixed to prevent dislodgement and
migration.

42. THANK
YOU