Pain following inguinal hernia repair
Pain following hernia repair is recognised as being a significant problem. Possible causes are sought, in an attempt to improve quality of life after repair and limit any long term associated debility. The technique of mesh fixation and the weight of the mesh used are thought to be part of the problem.
Mesh fixation: Penetrative fixation of the mesh, using titanium staples or screws, was universally employed in laparoscopic hernia repair, when the operation was first popularised in the early 1990’s. However, it became apparent that fixation could cause problems. Placement of the titanium staples or screws in the wrong areas could injure nerves, over-vigorous (deep) placement could tether muscle layers together and contraction of the mesh (which occurs with all types of mesh to some extent) could cause pain by dragging the fixation points through tissues. To reduce the chance pain from fixation occurring, options of absorbable fixation screws, glue fixation, “Velcro-style” mesh or no fixation at all have been proposed. The first three come with increased costs, the forth with increased possibility of recurrence.
Mesh weight: A relatively heavy-weight, narrow pore mesh was standard for hernia repairs for many years. More recently, the use of lightweight, wide-pore mesh has been advocated as causing less foreign body sensation. Lightweight, wide-pore mesh is also associated with less contraction. It also comes with increased costs.
My approach: I have persisted with penetrative fixation using titanium screws, but have done so in a logical manner, monitoring short and long term patient outcomes through my audit process. In my series, chronic pain is lower than any series in the surgical literature, despite the routine use of penetrative fixation. This appears to be because I fix the mesh onto the surface of the pubic bone only, restricting this to just one edge of the mesh, to stabilise it. Penetrative fixation to the surface of bone does not cause pain at all. In contrast, most colleagues fix to the soft tissues (muscle/ligaments) adjacent to the pubic bone, with potential for injury and pain. They also tend to fix the mesh around the edges, which means that, as the mesh contracts on itself, points of fixation are dragged through the soft tissues, with more likelihood of pain. In addition, in my series there does not appear to be any outcome difference between those who received standard weight mesh and those with light weight mesh; foreign body sensation does not appear to be a factor with mesh placed deep to all muscle layers and if the mesh is fixed to the bone at one edge only, it slides freely across the tissues regardless of the amount of contraction that occurs.
When teaching the operation, I recommend that, if fixation is used, the above issues should be considered. However, I also recognise that most surgeons will persist in using penetrative fixation in what I consider an inappropriate fashion, in which case the more costly options of glue, “Velcro” mesh or absorbable fixation may be preferable.