22
|
WOODFORD Which mesh material is best? The technology of meshes advances
FIGURE 1 Image of the left ventrolateral abdomen; cranial is to the left and caudal to the right showing the swelling.
Davis and Rakestraw ( 2002 ) described their management of 60
surgical cases: 24 treated with mesh hernioplasty and 36 with pri- mary suture repair. In each category, 30% showed residual post- op herniation, from 1 to 10 cm defects, draining tracts with 15% having continued drainage, requiring revision or being nonsurvivors. How- ever, ultimately, 88% returned to intended use, perhaps again indi- cating, do we need to risk a mesh to strive for perfection or are we better with a simpler approach to achieve a functional repair? They note the confounding factor in their comparison, that may be present in other comparative publications between mesh hernioplasty and primary suture, was that the former had larger hernias. Whitfield- Cargile et al. ( 2011 ) from the same centre as Davis et al. seemed to have sealed the fate of mesh hernioplasty with better results with primary closure in comparison to mesh hernioplasty with no appar- ent difference (57 cases: 38 primary and 19 mesh) between the two groups, with regard to the size of the hernia or the weight of the horse. They noted that the horses undergoing mesh hernioplasty had longer surgical time, longer hospital time, more post- operative com- plications, and longer intervals before resuming intended activities than primary repair cases. They describe a 2.5% incidence of partial reherniation with the primary technique which they managed with an abdominal bandage. Resuming normal activities may be a better line of inquiry than absence of hernia post- op, but the tale does not end here. Toth and Schumacher ( 2019 ) noted that primary repair for them risked leaving small hernial pockets which perhaps led them to develop a mesh hernioplasty external to the external rectus sheath (onlay) to support a primary repair (Kelmer & Schumacher, 2008 ). Their 11% complication rate with primary repair alone included a par- tial failure of the hernial repair. The nylon tape technique described later by H. Neal (1997) (Personal communication/BEVA meeting), may overcome this. Toth and Schumacher ( 2019 ) describe mesh re- moval from this plane as relatively easy. The Kelmer technique may be particularly applicable for a long line of multiple small hernias. The author saw such a case in a horse that showed colic on most occasions when the horse was ridden, but euthanasia without post- mortem was selected in this case and so the truth remains unknown.
leaving multiple options for the surgeon from biological meshes made from submucosal, dermal or pericardial tissues through to synthetic meshes with biological sidedness known as composite meshes such as the Symbotex mesh (Medtronic) described for inguinal herniorrhaphy (Wilderjans & Meulyzer, 2022 ). These composite meshes are microp- orous on one side which minimises tissue adherence attachment and infiltration and is placed to face the abdominal viscera, for example, and macroporous on the other side to encourages incorporation of tissue such as the layers of the body wall. Elce discusses the plastic mesh used in her series as perhaps being responsible for some of the complications but Toth and Schumacher ( 2019 ) describe three mesh material options, as suitable for their onlay mesh hernioplasty. A case report (Haupt et al., 2015 ) described an absorbable silk mesh (SERI Surgical Scaffold) placed retroperitoneally (classification: preperito- neal) with a good result. Slow absorption of such meshes may lead to a long period of drainage with infected cases, before material absorp- tion and discharge ceases. Location of mesh. Meshes have been implanted at each of the
available planes and so this decision is complicated and maybe there is no difference in results. The classification of mesh location in relation to the abdominal
wall through the different planes of the abdominal wall from intra- abdominal to subcutaneous has been borrowed from human litera- ture (Holihan et al., 2016 ) and is described (Toth & Schumacher, 2018 ). Mesh infections probably, have to be managed rather like inter-
nal fixation infections by trying to keep the implant in place for long enough to allow sufficient structural repair before implant removal is required, hoping structural repair wins this race. The use of absorb- able sutures to secure the mesh helps with post- operative revision. Ideally an infected mesh is left 2– 3 months to allow enough fibrosis to prevent reherniation after revision. Surgical management starts with a period of 4 months between
laparotomy and incisional hernia repair to eliminate tissue microbial colonisation and achieve a hard fibrous hernial ring. Some recommend pre- operatively reducing the bulk of the colon by feeding low- fibre diet for 1 week and then withhold food for 24 h pre op. Fractious horses may benefit from acclimatisation to a hernial belt pre op. Although there are many variations on the nuances of incisional
herniorrhaphy repair technique, thankfully there are principles spe- cific to this procedure— this procedure underwrites the importance of Halsted ' s Principles. How much of the skin/SQ layer should be discarded to allow
acceptable tension levels during closure and good cosmesis? If the approach is a fusiform incision, then 50% of the cutaneous hernial sac from a left and a right lateral perspective works. The next useful principle is to direct dissection, to preserve a thick single layer cuta- neous/subcutaneous shelf (Whitfield- Cargile et al., 2011 ) to maxi- mise vascularity. Lateral dissection must mobilise the hernial ring to reduce suture tension. Herniorrhaphy sutures will have insufficient power if they fail to incorporate the robust solid body wall tissue, lateral to the hernial ring perimeter. The thinner weaker central
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
