ISSN: 2754-8880
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Edited by
A.Hussain
Submitted 14 Jul. 2023
Accepted 08 Nov. 2023
Citation
Sudin Daniel, Maseera
Solkar, Rishabh Sehgal,
Kallingal Riyad .A pragmatic
study of Porcine Acellular
Dermal Matrix Mesh in
Ventral and Parastomal
Hernia repairs. Evaluation of
outcomes from a tertiary
centre.:BJOSS::2025:(4);112-
118
A Pragmatic Study Of Porcine Acellular Dermal
Matrix Mesh In Ventral And Parastomal Hernia
Repairs. Evaluation Of Outcomes From A
Tertiary Centre
S Daniel
1*
, M Solkar
1
, R Sehgal
1
, and K Riyad
1
1
Leeds Teaching Hospitals NHS Trust. John Goligher Colorectal Unit.
*
Correspondence author : Sudin Daniel, MBBS, MS, DNB, FRCSEd, ChM, Phone: 07886993551
Email: sudinvd@hotmail.com
O R IGI N A L
Abstract
Aims and Objectives: The incidence of complex ventral hernias and those contaminated is
increasing. Synthetic meshes are not favoured due to the increased risk of wound complications.
Biologic meshes are used as an alternative given their biocompatible safety, but there is a lack
of strong evidence to recommend its routine use. Hence, it is up to institutions to evaluate the
safety and efficacy to support its continuing usage, which is the basis of this study.
Methods: A retrospective review of a prospectively maintained PADM mesh database was
performed, focusing on midline and parastomal hernias. Demographic data, surgical techniques,
and short- and long-term complications were reviewed.
Results: 71cases (acute/elective 10/61) were included. The median age group, sex ratio in
the acute and elective groups were 67 years (36-83yrs) and 62years (25-93yrs), 2:1 and 4:3
respectively. Mean ASA score was 3.4 in the acute and 2.4 in the elective group. Midline hernias
constituted 37/ 61 (60%), and Parastomal hernias, 40% (24/61). Component separation was
performed in 29 cases, which include bilateral anterior component separation in 16, unilateral
anterior component in 11, and posterior component separation in 2. Median length of stay was
11days (1-180d) and 15 days (1-159d) in the elective and acute groups, respectively. Median
length of follow-up was 18 months (12 -72 months). There were 5 deaths within 90 days.
Recurrences were noted in 6/37 (16%) midline repairs and 8/24 (33%) parastomal hernias.
Conclusion: Our limited PADM series showed acceptable results in comparison with available
studies. As such, we find it a useful adjunct in the repair of complex ventral hernias.
Introduction
Complex ventral hernia repair is challenging, with the jury still out as to the type of mesh to
be used in contaminated settings. At the same time, the prevalence of clean-contaminated
and contaminated ventral hernias is increasing, with a risk of recurrences and need for further
repairs (
1
). Previous studies have shown that in complex ventral hernias biological meshes which
may be used in conjunction with component separation are superior to fascial closure with sutures
alone (
2
). The Ventral Hernia Working Group (VHWG) suggested the use of Biological meshes in
contaminated settings, and the modified classification of Ventral Hernias based on risk factors
for complications, seem to reliably predict short-term outcomes following repair, especially the
need for further hernia surgery, which is about 10% (
1
). Although about 200 times costlier
than synthetic meshes, the safety profile in terms of surgical site occurrences (SSO) of biological
meshes was similar to synthetic meshes in contaminated hernias (
3
). Recurrence rates of up to
32% have been reported following ventral hernia repair with Biologic mesh (
4
). In the repair of
Parastomal Hernias, Biological mesh was associated with recurrence rates of up to 20.5%(5).
It appears thus, that institutions using Biological Meshes should be able to justify its continuing
use even in special circumstances considering the equivocal data and weak evidence available in
literature to recommend its use. We feel that it would be possible by doing a pragmatic study of
the use of biological mesh and its outcomes as and how it happens in routine care, rather than in
an experimental or controlled setting.
Aims
Against the above background, we proposed to evaluate the short- and long-term outcomes of
Porcine Acellular Dermal Matrix (PADM) mesh in complex ventral hernia and parastomal hernia
repairs at our tertiary referral center.
Methods
A retrospective review of a prospectively maintained PADM mesh database was performed
between 01/05/2016 and 30/09/2022. Focus was aimed towards midline and parastomal
hernias. Electronic charts were reviewed to obtain demographic data and surgical logs were
interrogated to obtain indication and surgical techniques. The primary outcome measured was
radiological recurrence. Secondary outcomes were Surgical site occurrences including seromas,
wound infections, and return to theatre. Those that required further hernia surgery for recurrences
were noted. All cases of Ventral and Parastomal hernias repaired using PADM was included.
Perineal, Diaphragmatic and Groin Hernias were excluded.
Results
Over a period of 6 years, PADM was used in the repair of 45 Ventral Hernias and 26 Parastomal
Hernias (N=71) in both elective and acute settings. Of these, there were 61 elective repairs and
10 acute repairs. Surgeons varied in their experience, techniques used, choice of suture materials,
and post-operative care, however, they all used the same type of PDAM mesh (Cellis R ). The
Largest size of mesh used was 30cmX 30cm. Mesh was cut to size and shape to suit the defect
and a variety of sutures like polydiaoxanone (PDS) or prolene were used to fix the mesh in an
interrupted or continuous fashion. Meshes were also placed in different positions as per surgeon
preference. All patients however had pre-operative antibiotic prophylaxis and postoperative DVT
prophylaxis as per hospital protocol.
For the sake of analysis, we grouped the cases into elective and acute repairs for both ventral and
parastomal hernias. All acute cases were admitted as an emergency from Accident and Emergency
with CT-proven small bowel obstruction or ischaemia. We used the modified VHWG classification
to group the ventral hernias into groups 1 or 2 and 3 or 4 Figure 1.
Table 1 shows the analysis of the cases in two groups, acute and elective. Although of similar age
and sex profile, acute cases were considerably sicker. It is noteworthy that the majority of the
ventral hernias (67%) belonged to modified classes 3 and 4 portraying the complexity of most
cases. Loss of Domain being a major issue in such cases, some form of component separation
technique was commonly employed (78%). The median BMI of Ventral Hernias was 32.25 kg/m2
(IQR 19.4-42.2), and that of Para Stomal Hernias was 32.4 kg/m2 (IQR 19-50.2). Risk factors
like smoking, Diabetes Mellitus, and COPD, were not very common accounting for less than
20% of cases in both Ventral and Parastomal Hernias. All cases were seen in the clinic after
discharge at least twice in the first twelve months. Long-term follow-up varied, with a median of
18 months, and IQR of 12-72 months. Three patients were lost to follow-up. There were five
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Figure 1. VHWG classification of Ventral Hernias and Kanter’s modified VHWG classification.
Adapted from 1 and 4.
deaths, three in the acute and two in elective groups. These were due to significant co-morbidities
and post-operative cardiorespiratory complications.
Table 1. Demographics And Analysis
N =71 Acute =10 Elective = 61
Age (median IQR) 67 yrs. (36-83) 62 yrs. (25-93)
Sex F:M 2:1 4:3
Mean ASA score 3.4 2.4
Parastomal Hernias (PH) 2 24
Ventral Hernias (VH) 8 (80%) 37 (60%)
VHWG classes 1 and 2 2/8 (25%) 12/37 (33%)
VHWG classes 3 and 4 6/8 (75%) 25/37 (67%)
Cases of component separation
(VH)
2 29/37 (78%)
Length of Stay (median IQR) 15 days (1-150) 11 days (1-180)
Recurrences after VH repair 1/8 (12%) 6/37 (16%)
Recurrences after PH repair ½ (50%) 8/24 (33%)
Figure 2, shows few high risk characteristics and their relative prevalence in the cohort of the
ventral hernias that were repaired
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Figure 2. Risk Factors In Complex Ventral Hernia Repairs.
Component Separation: Twenty-nine (29/37, 78%) elective ventral hernia repairs and two of
the eight (2/8, 25%) acute ventral hernias had component separation. Of the elective group,
16/29 (55%) had bilateral anterior component separation, 11/29 (38%) had unilateral anterior
component separation, and 2/29 (7%) had posterior component separation. Of the acute group,
2/8 ventral hernias had unilateral component separation.
Recurrences following Ventral Hernia Repair: There were 16% (6/37) CT-proven recurrences after
elective repairs. The median BMI in this group was 31 Kg/m2 (IQR 20.2 – 34.6). Four recurrences
(84%) happened with onlay mesh repair, and one each with IPOM and sub-lay mesh repairs. 80%
(5/6) recurrences occurred in VHWG classes 3 or 4. Only one out of eight (12%) acute ventral
hernia repairs had a recurrence. This again was a VHWG class 4 hernia with anterior component
separation and onlay mesh. Two-component separations in the elective group and one in the
acute group had a recurrence. Thus, the total recurrence rate after component separation in
either group was 8% (3/39). Four patients (4/45, 9%) who had recurrence went on to have further
hernia repair in the follow-up period.
Recurrences following parastomal hernia repairs: There were 33% (8/24) recurrences after elective
PH repair and one out of two acute repairs recurred. The median BMI of this group was 34.7
Kg/m2 (IQR 22.1- 41.5). Of the PH recurrences in the elective group, 3 each had IPOM and
sub-lay repairs and 2 had onlay repairs. In the acute group, the only recurrence was in IPOM repair.
Two patients (2/26, 8%) went on to have further hernia repairs. Secondary Outcomes. Seromas
were the commonest surgical site occurrence, 30% (22/71), followed by wound infection in 33%
(24/71) in VH and PH repairs. 15% (11/71) of the patients returned to theatre for wound-related
complications or perioperative complications.
Discussion
For the sake of planning operative repair, it is important to define what a complex abdominal wall
hernia is. A consensus published in Netherlands by Slater and colleagues classified it into four
major categories based on location and size of defect, presence of contamination and condition
of soft tissue, co-morbidities, and clinical picture. These were further divided into grades, minor,
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moderate, and severe (
6
). However, this classification is itself complex. The VHWG classification,
later modified by Kanters etal; is simpler (
4
;
7
). This too, falls short of accounting for the size of
defect or risk of recurrence. A recent French survey aimed to define “giant” ventral hernias as
those with loss of domain volume of hernia over 30% of abdominal volume (
8
). The European
Hernia Society has developed a platform to record ventral hernia repairs and postoperative
complications. They suggest using the European Hernia Society classification of ventral hernias
based on size and location, which do not accommodate for co-morbidities or the nature of the
hernia defect. They however suggested that institutions using prosthetic meshes should attest to
the safety of the products they use as a recommendation cannot be made in this regard based
on any studies so far considering the various products available in the market. Quality control is
necessary, and it is down to the institutions and surgeons to ensure that (9).
A large population-based study in the US showed that following incisional hernia repair, about 12%
had to undergo further repair in five years, and this figure doubles if no mesh was used (
10
). This
finding was attested by a Dutch multicentre trial comparing suture vs mesh repair of incisional
hernias which found double the number of recurrences in the suture repair group; ( 43% vs
24%) (
11
). Anterior component separation (ACS) is commonly used in bigger defects, with the
repair augmented using various types of meshes. Recurrence rates ranged between 10% to
30% within five years and surgical site infections ranged between 26 to 42%. Biological mesh
compared to soft polypropylene mesh did not add any additional advantage to the strength and
durability of these repairs (
12
). Transversus Abdominis Release (TAR) on the other hand was
found to be useful in repairing bigger defects with even less complications. A recent systematic
review quoted a two-year recurrence rate of 4%, and surgical site occurrence around 15%. The
recurrence is about a third and SSO is nearly half compared to ACS (13).
Thus, it would be fair to say that a standardised approach to complex ventral hernia repair is far
from practical. From, the optimisation of co-morbidities to the type of repair and selection of
meshes, several permutations and combinations are available, each of which could be applied to
a given case depending on the circumstances. Biological meshes, and PADM as discussed in this
paper, are therefore essential tools that should be available in the surgeon’s stockpile. Therefore,
any study about the outcomes of PADM meshes in complex ventral hernias should ideally be
a pragmatic one, and not in a controlled or experimental setting. This is what we have tried to
emulate in this paper.
The recurrence rates following complex ventral hernia repairs using biological meshes have been
reported to be between 12% to 33% and that of wound complications to be between 15% to
40% (
14
;
15
). The present study has shown a recurrence rate of 16% for ventral hernias and 33%
for parastomal hernias. Surgical site occurrences were around 30%. These observations are in
keeping with the available literature. In addition, component separation with PADM (CS/PADM)
was found to be superior to conventional bridged repair, quoting a recurrence rate of 17% for
CS/PADM (
16
). Our cohort showed much less recurrence after CS/PADM, 8%. When considering
biological meshes, there is little to choose between porcine and bovine dermal matrix meshes as
the surgical site occurrences and recurrence rates of hernias were similar (17).
Multicentre blinded trials comparing synthetic mesh with biological mesh showed a three-fold
reduction in hernia recurrence with synthetic mesh in clean contaminated and contaminated fields.
The safety profile and need to return to the theatre were similar, although biological meshes were
significantly costlier (
3
). A recent meta-analysis from Spain has showed no meaningful differ-
ences between mesh types in high-risk ventral hernias, but biosynthetic meshes had favourable
outcomes in terms of reduced recurrence rate of 9% and 14% incidence of SSI (18).
Our study has some obvious drawbacks. Being a retrospective study, the data collection was
not exhaustive, yet we were able to obtain meaningful data regarding BMI and risk factors, ASA
status, and VHWG classification. The lack of standardisation of operating technique and mesh
placement makes comparisons with other similar studies impossible. However, we feel that our
study is more pragmatic and hence likely to reflect the performance of similar institutions in the
United Kingdom. The study represents what came through our doors over the six years and the
outcomes of PADM repair performed in this cohort. This could be taken as a quality control
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exercise in complex ventral hernias, to justify its continuing use. Such a practice is encouraged
by the EHS. This in our view is essential as we do not yet have any strong evidence base to
recommend any technique or mesh in the management of such cases. It thus comes down to
the institutions and the surgical teams to choose the type of mesh they would want to use in
high-risk ventral hernias.
Conclusion
PADM mesh was shown to be safe with recurrence rates and wound complications well within
reported figures in literature. As such, our study and available literature provide no support to
deny its use in the repair of complex high-risk ventral hernias. More such data from similar centres
would help to consolidate and generate a wider consensus on the use of PADM in complex ventral
hernias.
Conflict Of Interest
All authors declare no conflict of interest of any kind.
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