Keywords
mesh migration - hernia repair - foreign body - ventral hernia - computed tomography
Introduction
Mesh migration is an unusual complication of hernia repair and is defined as mesh
that resulted in the invasion of any anatomical region other than the area intended
for the repair. It occurs years after surgery. Mesh migration can be primary due to
inadequate securing which happens in the same plane or secondary that is transanatomical
and usually due to inflammation or infection. Migration of mesh into the bowel can
cause complications such as obstruction, infection, or fistula formation. This report
discusses a rare occurrence of spontaneous migration of the ventral hernia repair
mesh into the bowel lumen (jejunum to rectum) which was retrieved without surgical
procedure.
Case Report
A 68-year-old female presented to the emergency department with abdominal pain, vomiting,
and distension. Significant history included paraumbilical hernia repair 5 years back
by laparoscopic intraperitoneal mesh placement using a composite mesh (containing
polyester and polyurethane). There was an episode of mesh infection postsurgery which
was managed conservatively.
Clinically, small bowel obstruction was suspected and hence a contrast-enhanced computed
tomography (CT) was done to evaluate the cause for obstruction which revealed recurrent
obstructed paraumbilical ventral hernia. The patient was taken up for open repair.
Intraoperatively, recurrent hernia containing small bowel was confirmed and a mass
of crumpled mesh (used in previous surgery) was noted at the repaired site. The mesh
area was fibrosed, adherent, and could not be removed. An open subcutaneous onlay
mesh repair was then done using a polypropylene mesh.
The immediate postoperative period was unremarkable. The patient presented again with
two to three episodes of small bowel obstruction after 1 year for which she underwent
a plain CT. The scan revealed dilated jejunal loops and an intraluminal hyperdensity
which was overlooked as fecal matter ([Fig. 1]). The repeat onlay mesh repair site was otherwise healthy. She was managed conservatively
and discharged. Seven months later, a repeat CT was done for recurrent small bowel
obstruction which revealed migration of the previously visualized hyperdense structure
in the jejunal lumen more distally with dilated proximal bowel ([Fig. 2]). Obstruction was again conservatively managed and since the surgeon could not palpate
the hard indurated feel of fibrosed initially placed mesh, a possibility of mesh migration
into the jejunum was suspected. The patient was kept on close follow-up. After a month,
the patient complained of a thread-like structure emerging through the anal canal.
On per rectal examination, a hard ball-like mass was felt in the rectum, and suture-like
material was visualized. A plain CT of the pelvis was done which showed the intraluminal
hyperdense structure within the rectal lumen ([Fig. 3]) with no obstructive changes. No pneumoperitoneum or intra-abdominal collection
was seen. Based on the clinical history of recurrent small bowel obstruction and intraluminal
migration of the hyperdense material, spontaneous migration of mesh up to the rectum
was suspected. The progressive migration of the mesh ball on CT is depicted in [Fig. 4]
Fig. 1 Plain computed tomography axial (A), coronal (B), and sagittal (C) sections at the time of admission with first episode of bowel obstruction show a
convoluted hyperdense intraluminal foreign body within the proximal jejunum (black
arrow). Mild adjacent inflammatory changes seen. Changes in the abdominal wall reflect
previous hernia repair (arrow head).
Fig. 2 Plain computed tomography with luminal positive contrast in sagittal (A) and coronal oblique planes (B) done after 7 months' interval, show migration of the intraluminal hyperdense structure
into distal jejunum (black arrow) with mild proximal bowel dilatation (white arrow).
Fig. 3 Plain computed tomography after 8 months' interval in coronal (A), sagittal (B), and axial planes (C) show further migration of the intraluminal foreign body into the rectum (black arrow).
No features of obstruction were seen.
Fig. 4 Sequential sagittal computed tomography scans on day of presentation (A), 7-month (B) and 8-month (C) show progressive migration of the mesh from jejunum to the rectum (black arrow).
The mesh ball was removed with intact sutures from the rectum under anesthesia ([Fig. 5]).
Fig. 5 (A) Retrieval of the fecal stained mesh (arrow) from the rectum using artery forceps.
(B) Intact mesh with sutures (arrow).
Discussion
Mesh migration is defined as “mesh that resulted in the invasion of any anatomical
region other than the area intended for the repair.”[1] It usually occurs years after surgery. The probable causes of mesh migration are
divided into primary and secondary. Primary is a mechanical migration where an inadequately
secured mesh moves along the planes of least resistance. Secondary migration occurs
through transanatomical planes as a result of inflammation, infection, and foreign
body reaction. Migration across anatomical planes is a very gradual process. Hence,
it is often asymptomatic and presents years later postsurgery.[2] Various terminologies are proposed,[1] including mesh “migration” if the whole mesh is displaced into an organ, mesh “erosion”
when a portion of the mesh is perforated into an organ while the remaining is outside,
and mesh “dislodgement” if the mesh movement is causing recurrence of hernia without
involving other organs. Mesh dislodgement can be partial or complete.
Incidence of mesh migration or erosion is 2% of 252 major mesh-related complications
following hernia repair in a Food and Drug Administration database review.[3] Symptoms related to the migration of mesh depend on which organ is involved. Erosion
into the bowel and urinary bladder are described.[4]
[5] Migration into the bowel can cause complications such as obstruction, infection,
or fistula formation.[4] There is mixed hypothesis on the exact predisposing factors of mesh erosion and
migration and commonly include subclinical infection and foreign body reaction.[6] In an experimental study by Wattanasirichaigoon,[7] a surgical sponge was retained in various positions in the abdomen of rats, and
migration of the sponge into bowel lumen was found without a hint of infection possibly
suggesting a dominant low-grade foreign body reaction.
Imaging plays a major role in suspecting mesh migration. Though most of the polypropylene
mesh are isodense to the parietal wall, when the mesh separates from its original
placement, it can be identified either by the presence of collection or inflammation
around it. Mesh migration with formation of collection is readily detected on ultrasound
by the presence of echogenic wavy structure within the fluid. Tackers that are radiodense
can help in mesh localization on CT. Mesh adhesion and focal thickening of the visceral
wall suggest underlying erosion.[4] Mesh when separates and enters the bowel, acquires hyperdensity likely due to trapping
of bowel contents and formation of a mesh ball which can be seen on CT and commonly
mistaken for a fecolith. It is important to note that although hyperdense fecoliths
are commonly seen in constipated colon, their presence in small bowel especially in
the proximal loops must not be ignored as a normal finding, especially when the patient
has a history of prior abdominal surgery.
The commonly described treatment of mesh migration is surgical, with or without resection
of the involved part. Erosion of mesh into bowel lumen and evacuation of the same
by rectum is extremely rare. To the best of our knowledge, two cases with the similar
presentation were mentioned in the literature. One of them was the preperitoneal placement
of polypropylene mesh evacuated manually from the rectum after 14 years.[8] Another case was polypropylene and expanded polytetrafluoroethylene mesh placed
intraperitoneally evacuated from the rectum after 2 years.[9] In both the above cases primary surgery was open repair and not laparoscopic.
Mesh migration into bowel in a post-laparoscopic repair was reported in two patients[6]
[10] where composite mesh and polypropylene with expanded polytetrafluoroethylene mesh
were used respectively. In both cases, management included surgical resection of the
bowel.
To our knowledge, our case is probably the first laparoscopic intraperitoneal composite
mesh that migrated and was removed without a surgical procedure. In this case mesh
migrated through the longest route, from proximal jejunum to rectum. The predisposing
factor in our case was probably infection which occurred postoperatively during the
initial hernia repair. Gradual low-grade subclinical infection or foreign body reaction
must have caused adjacent (jejunal) bowel erosion and luminal migration with spontaneous
healing of the bowel defect. Migration of the mesh ball further down caused intermittent
small bowel obstruction symptoms. Once the mesh ball reached the rectum, the sutures
were felt by the patient and hence led to successful retrieval without any surgical
intervention. The consensus on when to opt for conservative measures or surgical treatment
depends on the severity of the obstruction, bowel inflammatory changes suggesting
impending perforation, or fistulization.
Because our patient had spontaneously settled episodes of bowel obstructions and the
mesh ball was seen well within the bowel lumen on follow-up CT scans, without wall
thickening or perforation, expectant management was decided upon avoiding surgical
intervention.
Conclusion
Mesh migration is an uncommon complication of hernia repair. The above case report
highlights this rare occurrence where spontaneous migration of mesh to the rectum
occurred facilitating retrieval without surgical intervention. It also emphasizes
the role of imaging in deciding the management options.
