Tissue attachment strength and adhesion formation of intraabdominal fixed meshes with cyanoacrylat glues.

Abstract

The aim of this study was to evaluate the technique of prosthetic mesh fixation in laparoscopic intraperitoneal incisional and ventral hernia repair using cyanoacrylat glue (Glubran GEM, Viareggio, Italy) in comparison with fixation methods using spiral tacks (Protack 5mm, Tyco) or transabdominal Prolene 4/0 sutures respectively.
Through a midline laparotomy 3 pieces (3 x 3cm) of mesh (n = 60) where fixed onto the intact peritoneum on either side of a midline laparotomy in 10 New Zealand White rabbits. Two types of meshes where compared: ePTFE meshes (Gore-Tex Dual Mesh W.L. Gore and Associates, Inc. Medical Products Division, Flagstaff, Arizona, USA) and polypropylene/ polyvinylfluorid meshes (Dyna Mesh - IPOM P.J. Dahlhausen and Co. GmbH, Germany). All animals were killed after 12 weeks. Upon scoring of the adhesions the prosthetic materials were excised en bloc with the anterior abdominal wall for tensile strength analysis and histologic evaluation.
In contrast to ePTFE meshes fixed with cyanoacrylat glue, PP meshes fixed with transabdominal sutures as well as with spiral tacks showed the highest percentage and tenacity of adhesions (p<0.033). Independent of the method of fixation, ePTFE meshes revealed a significantly higher shrinkage than PP prosthesis (41% vs 17% related to original mesh surface; p<0.033). The strength of the mesh incorporation was significantly higher in PP meshes (p<0.033). Fixation of PP meshes with cyanoacrylat glue showed an equivalent tensile strength as ePTFE meshes fixed with spiral tacks (6.6 +/- 2.7 N vs 6.6 +/- 3.1N).
In this rabbit model, intraabdominal fixation of PP composite meshes with cyanoacrylat glue was equivalent to ePTFE mesh fixation with spiral tacks concerning tensile strength analysis. Adhesions between mesh and abdominal wall were found more frequently after PP fixation. In contrast, mesh shrinkage was more evident after ePTFE mesh implantation.

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EU RO PE AN JOUR NAL OF MED I CAL RE SEARCH1
Abstract
Objektiv: The aim of this study was to evaluate the
technique of prosthetic mesh fixation in laparoscopic
intraperitoneal incisional and ventral hernia repair us-
ing cyanoacrylat glue (Glubran®GEM, Viareggio,
Italy) in comparison with fixation methods using spiral
tacks (Protack 5mm, Tyco) or transabdominal Prolene®
4/0 sutures respectively.
Method: Through a midline laparotomy 3 pieces (3 x
3cm) of mesh (n = 60) where fixed onto the intact
peritoneum on either side of a midline laparotomy in
10 New Zealand White rabbits. Two types of meshes
where compared: ePTFE meshes (Gore-Tex Dual
Mesh W.L. Gore & Associates, Inc. Medical Products
Division, Flagstaff, Arizona, USA) and polypropylene/
polyvinylfluorid meshes (Dyna Mesh®- IPOM P.J.
Dahl hausen & Co. GmbH, Germany). All animals
were killed after 12 weeks. Upon scoring of the adhe-
sions the prosthetic materials were excised en bloc
with the anterior abdominal wall for tensile strength
analysis and histologic evaluation.
Results: In contrast to ePTFE meshes fixed with
cyanoacrylat glue, PP meshes fixed with transabdomi-
nal sutures as well as with spiral tacks showed the high-
est percentage and tenacity of adhesions (p<0.033).
Independent of the method of fixation, ePTFE mesh-
es revealed a significantly higher shrinkage than PP
prosthesis (41% vs 17% related to original mesh sur-
face; p<0.033). The strength of the mesh incorpora-
tion was significantly higher in PP meshes (p<0.033).
Fixation of PP meshes with cyanoacrylat glue showed
an equivalent tensile strength as ePTFE meshes fixed
with spiral tacks (6.6 ± 2.7 N vs 6.6 ± 3.1N)
Conclusion: In this rabbit model, intraabdominal fixa-
tion of PP composite meshes with cyanoacrylat glue
was equivalent to ePTFE mesh fixation with spiral
tacks concerning tensile strength analysis. Adhesions
between mesh and abdominal wall were found more
frequently after PP fixation. In contrast, mesh shrink-
age was more evident after ePTFE mesh implantation.
Key words: laparoscopic incisional hernia repair, fixa-
tion devices, cyanoacrylat glue, tensile strength, in-
traabdominal adhesions
INTRODUCTION
While an open surgical technique represented the gold
standard of incisional hernia repair for a long time, the
introduction of laparoscopic surgery in 1990 by
Leblanc opened up new vistas in hernia surgery [1].
Shorter hospitalization, a lower rate of infected
wounds, less pain and a lower recurrence rate were the
potential advantages of the new technique. The intro-
duction of mesh techniques has further lowered the
cases of recurrence [2, 3]. The incidence of chronic
pain is still unclear as only few studies have focussed
on long term recurrence, pain or quality of life [4]. The
source of chronic pain is still unclear. Nerve irritation
caused by the inflammatory reaction against the mesh
or scar tissue formation as well as nerve entrapment by
regularly used fixation devices (spiral tacks, transfascial
sutures) are the suspected causes. The aim of this
study was to evaluate the technique of prosthetic mesh
fixation in laparoscopic intraperitoneal incisional and
ventral hernia repair using cyanoacrylat glue (Glubran®
GEM, Viareggio, Italy) in comparison with fixation
methods using spiral tacks (Protack 5mm, Tyco) or
transabdominal Prolene 4/0 sutures respectively.
MATERIALS AND METHODS
10 New Zealand white rabbits, weighing 2500-3000 g
were used in this study. Prior to the intervention ani-
mals were acclimatized to the vivarium for two weeks.
They were kept under standard laboratory conditions
(temperature 20ºC, relative humidity 50-60%, 12 light/
12 h dark, feed and water ad libidum). In each animal
6 pieces of 3 x 3cm meshes (3 meshes of ePTFE and
3 meshes of polypropylene/ polyvinylfluorid (PP) on
either side of the midline incision) were intraabdomi-
nally attached to the peritoneum. This study was con-
ducted with the approval of the government of Ober-
bayern.
SURGICAL PROCEDURE
Anaesthesia was performed with an intramuscular in-
jection of medetomidin, fentanyl and midazolam. A
Eur J Med Res (2008) 13: 1-7 © I. Holzapfel Publishers 2008
TISSUE ATTACHMENT STRENGTH AND ADHESION FORMATION OF
INTRAABDOMINAL FIXED MESHES WITH CYANOACRYLAT GLUES
R. Ladurner1, I. Drosse2, S. Seitz1, W. Plitz3,G. Barbaryka4, M. Siebeck1, D. Bürklein1, C. Kirchhoff1,
S. Buhman5, W. Mutschler1, M. Schieker1,2, T. Mussack1
1Department of Surgery Innenstadt, Ludwig-Maximilians-University (LMU) Munich,
2Experimental Surgery and Regenerative Medicine, Department of Surgery Innenstadt, University of Munich (LMU)
3Department of Orthopaedics Großhadern, University of Munich (LMU)
4Department of Pathology Innenstadt, University of Munich (LMU)
5Department of Radiology, University of Munich (LMU), Germany

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ventral midline incision of 10cm from the xiphoid
process to the pubic symphysis was made. Three
ePTFE (expanded Polytretrafluorethylene) meshes
(3 x 3cm) were implanted on the left side of the mid-
line incision, three polypropylene (PP) meshes (3 x
3cm) were placed on the right side. All meshes were
spaced at 2 cm and fixated with a distance of 2 cm
to the incision. One of each mesh types was fixed us-
ing either four spiral tacks on the corners of the im-
plants (Protack 5mm, Tyco), four transabdominal
Prolene®4/0 sutures or cyanoacrylat glue (Glubran®
GEM, Viareggio, Italy) applied evenly to the surface
of the respective mesh. Following implantation the
peritoneum and the midline fascia were closed in a
running suture pattern using Vicryl®2/0. Subcuta-
neous tissue was closed with a subcuticular Vicryl®
4/0 suture. After the operation the rabbits were
returned to their individual cages. Postoperatively
animals received an analgesic (Tramudin®), if neces-
sary. All animals were killed 12 weeks after mesh
implantation by a pentobarbital overdose (300mg/kg,
i.v.).
SCORING OF ADHESIONS
Adhesion formation between the meshes and viscera
and the large omentum respectively was evaluated.
Density of the adhesions was evaluate macroscopically
via a midline laparotomy using a scoring scale as sug-
gested by Garrard 1999 (Table 1) [5, 6].
The percentage of adhesions covering the mesh
surface was also recorded. Each mesh was subdivided
into ten fields and for each of these fields the surface
percentage covered by adhesions was determined sep-
arately.
MESH SHRINKAGE AND TENSILE STRENGTH
The entire abdominal wall was excised with the mesh-
es. To evaluate shrinkage, the surface area of each
mesh was measured compared with the original size
(9cm2). From each abdominal wall/mesh sample a
specimen measuring 0.5 x 3 cm was cut for histo-
logy. The rest of each sample underwent fixation
strength testing using a tensiometer (Zwick 0Z01).
For this purpose the contact between the mesh
and the abdominal wall was loosened on one side to
clamp taut the free borders in the test machine.
The mesh was then removed from the abdominal
wall with a continuous displacement rate of 100
mm/min. Displacement force was recorded simulta-
neously. The maximum tensile strength was measured
(Newton).
HISTOLOGY
The abdominal wall/ mesh samples were fixed in 4%
formaldehyde, embedded in paraffin and sectioned at
7-10µm. All tissue sections were stained with hema-
toxylin and eosin, Goldner´s trichrome, as well as
Ladewig staining (fibrin stains). Additionally, im-
munhistochemical analysis was carried out on selected
samples of the different implant types using antibod-
ies against human panzytoceratine which proved posi-
tive also for rabbit tissue. The aim of the light micro-
scopical assessment was to give a thorough description
of the tissue response to the different implant materi-
als. The amount and quality of an inflammatory re-
sponse and the extent of scar tissue formation were of
particular interest. For the evaluation, special attention
was paid to the interface between the abdominal wall
and the meshes. To determine and compare the in-
flammatory response to the different materials and
fixation devices used, all nucleated cells including fi-
brocytes, macrophages, lymphocytes, endothelial cells
and monocytes were counted per high-powered field
(HPF) in HE staining. The occurence of foreign body
giant cells was noted separately. Trichrome staining
was used to determine the dimensions of fibrous tis-
sue around the implants. The Ladewig staining was
used to assess whether or not fibrinous exsudate could
still be seen in the newly formed tissue around the im-
plants (10x magnification) (Fig. 1).
STATISTICAL ANALYSIS
Differences between the intervention groups (Gore
Stapler, Gore Suture, Gore Glubran, Dyna Stapler,
Dyna Suture, Dyna Glubran) were tested for signifi-
cance using ANOVA post hoc with Bonferroni-Dunn
correction. The comparisons were performed using
STATVIEW 4.5 software (Abacus Concepts, Berkeley,
CA). In view of the multiple tests between groups, sig-
nificance levels were set as P <0.0033, to indicate a
global significance level of P <0.05-
RESULTS
No intraoperative complications occured. All rabbits
had an uneventful recovery and remained free from in-
fection, disturbance of the wound healing or bowel
obstruction. All prosthesis were completely reperi-
tonealized at explantation and we noticed no mesh mi-
gration. We compared the density of the adhesions
(Table 2) and the percentage of the adhesions cover-
ing the mesh surface (Table 3). The density and the
percentage of the adhesions were significantly less in
EUROPEAN JOURNAL OF MEDICAL RESEARCH2
Table 1. Adhesion scale from Garrard et al. and Joels et al. [5, 6].
Type of adhesions Score
No adhesions 1
Filmy adhesions, easily broken manually 2
Dense adhesions, requiring blunt dissection to separate viscera from mesh 3
Very dense adhesions, viscera matted to mesh surface, requiring sharp dissection to separate viscera from mesh 4

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the ePTFE group compared to the PP meshes. ePTFE
meshes fixed with cyanoacrylat glue showed the low-
est, PP meshes fixed with transfabdominal sutures and
tacks the highest percentage of adhesions. Indepen-
dent of the fixation modality ePTFE meshes showed
in general statistically significant more pronounced
shrinkage than PP prosthesis (Table 4). The strength
of the mesh incorporation was significantly higher in
PP meshes. Fixation with transabdominal sutures was
significantly stronger (p<0.033) in both ePTFE and
PP meshes in comparison to spiral tacks and
Glubran®. The strongest fixation device in both im-
plant types proved to be the transabdominal sutures.
Tensile strength of ePTFE meshes fixed by spiral
tacks was equal to PP meshes fixed with Glubran®.
The relative macroporosity of PP meshes allowed
for slightly more ingrowth of fibrous tissue and ac-
cordingly scar formation directly around and in close
proximity to the fibres of the implant itself, compared
to the ePTFE meshes. Comparing the groups, the in-
flammatory reaction to the latter was slightly higher
when using the amount of nucleated cells per HPF as
an indicator. While in the PP meshes the total amount
of cells was slightly lower and these were equally dis-
tributed throughout the newly formed tissue, an over-
all higher number of cells could be seen with the
ePTFE meshes. Beyond that, the distribution of cells
differed, in that a conspicuously high amount of
mononuclear granulocytes were found in a palisade-
like order directly on the surface of the implant mater-
EUROPEAN JOURNAL OF MEDICAL RESEARCH3
Fig. 1.
Pictures A-D Goldner´s trichrome, 5x magnification, bar: 100µm
Pictures E-H Ladewig, 10x magnification, bar: 100µm
Pictures I-L HE, 20x magnification, bar: 50µm
Pictures M-P Pancytokeratin, 40x magnification, bar: 20µm
A,E,I,M : Gore-Tex®mesh (staples/sutures)
D,H,L,P : Gore-Tex®mesh (Glubran®)
B,F,J,N : DynaMesh-Ipom®(staples/sutures)
C,G,K,O : DynaMesh-Ipom®(Glubran®)
Stainings in Goldner´s trichrome allow easy assessment of the extent of fibrous tissue at the interface between the implants and the
abdominal wall; Ladewig staining specifically marks fibrin which was not seen twelve weeks postoperatively; in HE note particular-
ly the arrangement of nucleated cells around the implant; mesothelialization of all implants was proven by panzytoceratin staining.

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ial. The occurence of foreign body giant cells did not
seem to differ between the groups. Mesothelialization,
however, could be shown for both implant materials
equally, using the aforementioned panzytoceratine
staining. The evaluation of the samples stained with
Ladewig revealed that regardless of the implant mater-
ial and fixation device used; only minor amounts of
fibrinous exsudate remained after an implantation pe-
riod of twelve weeks.
DISCUSSION
Incisional hernia complicate about 10% of laparo-
tomies and the repair with conventional techniques is
associated with high recurrence rates of 30-50 % [2,
7, 8]. Surgical repair using different prosthesis is be-
coming increasingly common. Different operative
techniques of hernioplasty are used. The laparoscopic
repair of incisional hernia is a relatively new ap-
proach. Recent studies of laparoscopic hernia repair
confirmed that the technique is associated with mini-
mal postoperative morbidity and shorter hospitaliza-
tion [9, 10]. The basic concept of this technique in-
cludes the dissection of all adhesions, clear identifica-
tion of the fascial defect, closure of the hernia by a
properly fixed mesh and a sufficient overlap of the
prosthesis [11]. For reliable fixation of the implant,
transabdominal sutures along the edges of the mesh
and helical coils made of titanium are used in combi-
nation. Whether or not mesh fixation with spiral tacks
alone is satisfactory is still up for discussion [11-13]. It
is widely recommended to use either six to eight non-
absorbable monofilament sutures at the corners and
along the edges of the implants or spiral tacks (Pro-
EUROPEAN JOURNAL OF MEDICAL RESEARCH4
Table 2. Adhesion tenacity from Garrard et al. and Joels et al. [5, 6].
Table 3. Percentage of the adhesions covering the mesh surface.

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tack®5mm Auto Suture) spaced at 1cm along the
borders of the meshes. Fatty tissue around the falci-
forme ligament and between the plicae mediales must
be dissected in order to allow sufficient fixation of
the spiral tacks. Using spiral tacks for fixation, ele-
ments with a diameter of 4 mm are screwed into the
abdominal wall at a depth of 3.8mm. Staples of a
conventional hernia stapler have a depth of penetra-
tion of 2 mm. In experimental studies on 20 human
cadavers the shear force resistance of a mesh fixed by
a spiral tacks was up to four times higher than that of
a mesh fixed with conventional staples [12]. Despite
certain drawbacks (see below) spiral tacks are so far
the best tool for mesh fixation in laparoscopic hernia
repair not least because the coil-like screwing move-
ment of the spiral tacks allows intraoperatively, if
necessary, easy removal of the devices without dam-
aging either tissue or mesh. Mesh fixation with trans-
abdominal sutures and spiral tacks are important mea-
sures to prevent mesh migration and hernia recur-
rence [9, 11]. None the less both fixation methods
have to be challenged since they can be the source of
persistent postoperative pain. It is widely agreed that
the most likely cause of such pain results either from
an entrapment of intercostals nerves coursing be-
tween different layers of the abdominal wall muscula-
ture or local muscle ischemia [14]. Beyond that the
use of spiral tacks is in some cases associated with
postoperative complications such as adhesion forma-
tion between the intestines and the abdominal wall or
- in rare cases – even perforations of the small intes-
tine [14-16].
The optimal solution for the fixation of intraperi-
toneal placed meshes has not been found yet. Cyano-
EUROPEAN JOURNAL OF MEDICAL RESEARCH5
Table 4. Mesh surface at explantation (cm2). Mean ± SD. The original size of each mesh was 9 cm2.
Table 5. Tensiometric Test.
Newton [N]
cm2