Title: Acellular Dermal Matrix for Chest Wall Reconstruction in a Rabbit Model
Authors: Luther H. Holton III, MD, Thomas L. Chung, DO, Ronald P. Silverman, MD,
Hafez Haerian, BA, Nelson H. Goldberg, MD, Whitney M. Burrows, MD, Andrea Gobin,
PhD, and Charles E. Butler, MD
Full-thickness defects of the lateral chest wall requiring surgical reconstruction can occur
as a result of trauma, infection, radiation, resection to treat a malignancy, or a
combination of these causes. The goals of chest wall reconstruction procedures include
maintaining an airtight seal of the pleural cavity, reestablishing chest wall integrity to
protect the contents of the thorax from trauma and infection, restoring sufficient rigidity
to prevent paradoxical chest wall motion, and, when possible, providing an acceptable
cosmetic result. Synthetic mesh is frequently used for chest wall reconstruction but
infection or exposure can occur and necessitate removal.1 Human acellular dermal
matrix (ADM) has been used to reconstruct musculofascial defects in the trunk with low
infection and herniation rates.2 ADM may have advantages over synthetic mesh for chest
wall reconstruction. This study compared outcomes and repair strengths of ADM to
expanded polytetrafluoroethylene (ePTFE) mesh used for repair of chest wall defects.
Methods: A 3cm2 full-thickness right lateral chest wall defects was created in each rabbit
by removing the central 3cm of the 6th through 8th ribs including the intervening
intercostal musculature and underlying parietal pleura. The defects were then repaired
with either ePTFE (n=8) or ADM (n=9). At 4 weeks, the animals were euthanized and
evaluated for: lung herniation/dehiscence; strength of adhesions between the implant and
intrapleural structures, and breaking strength of the implant materials and the implantfascial interface. Tissue sections were analyzed with standard histology to evaluate
cellular infiltration/repopulation. Frozen sections were procured and processed for
immunohistochemical staining with anti-CD31 antibody, a marker for vascular
endothelium.
Results: No animals experienced respiratory complications and no paradoxical chest wall
motion was detected for any animal. Additionally, no herniation or dehiscence occurred
with either material. The incidence and strength of adhesions was similar between
materials (Table I and Figure 1). The mean breaking strength of the ADM-fascia interface
(14.2 ± 8.7 N) was greater than the ePTFE-fascia interface (10.0 ± 5.7 N; p=0.028) and
similar to the rib-intercostal-rib interface of the contralateral native chest wall (13.6 ± 5.1
N) (Tables II and III). The ADM grafts became infiltrated with cells and vascularized
after implantation.
Conclusions: ADM appears to be a reasonable option for reconstruction of lateral chest
wall defects. ADM used for chest wall reconstruction results in greater implant-defect
interface strength than ePTFE with a similar adhesion profile. The ability of ADM to
become vascularized and remodeled by autologous cells and to resist infection may be
advantageous for chest wall reconstruction. Further studies will be important to determine
the long-term outcome of biologic materials used in chest wall reconstruction.
Table I. General Wound Complications Stratified by Type of Graft Material
No. Cases (%) by Graft Type
ADM (n= 9)
ePTFE (n = 8)
+
Complications
Seroma
3 (33%)
2 (25%)
Dehiscence
0
0
Abscess
0
0
Herniation
0
0
Adhesions+
Incidence
Mean grade*
8 (89%)
1.3 ± 0.9
8 (100%)
2.0 ± 1.0
+
No significant difference between ADM and ePTFE for any complication or for the
incidence or grade of adhesions.
*
Adhesion grade: 0 = none, 1 = easily freed with gentle tension, 2 = freed with blunt
dissection, and 3 = freed with sharp dissection. P = 0.16 for difference between ADM
and ePTFE.
Table II. Results of Tensile Strength Testing
No.
Mean Ultimate Tensile
Material Tested
Strips
Range, N
Strength ± SD, N
Tested
Native chest wall
24
13.6 ± 5.1
4.1-21.8
ePTFE-fascial junction
30
10.0 ± 5.7
1.5-27.7
ADM-fascial junction
32
14.2 ± 8.7
2.3-36.3
Explanted ADM
9
71.0 ± 22.9*
39.7-107.7
Non-implanted ADM
18
68.1 ± 16.5
32.9-100.1
Non-implanted ePTFE
24
62.5 ± 4.1
56.2-71.5
* The values for this group may be artificially low because 6 of 9 samples slipped from
the clamps before the force required to cause failure could be reached.
Table III. Comparison of Ultimate Tensile Strength between Groups
Groups Compared
p Value *
ADM-fascial group vs. ePTFE-fascial group
0.028
ADM-fascial group vs. native chest
0.744
ePTFE-fascial group vs. native chest
0.018
Explanted ADM vs. non-implanted ADM
0.748
Non-implanted ePTFE vs. non-implanted ADM
0.170
Two-tailed Student’s t-test.
2
Mean Breaking Strength (N)
25.00
20.00
15.00
10.00
5.00
0.00
A-F
G-F
NC
Figure 1. Mean breaking strength (Newtons) of ADM-fascia (A-F) interface (n=32),
ePTFE-fascia (G-F) interface (n=30), and native chest wall (NC) (n=24).
References
1. Szczerba, S. R., Dumanian, G. A. Definitive surgical treatment of infected or exposed
ventral hernia mesh. Ann. Surg. 237(3): 437, 2003.
2. Butler, C. E., Langstein, H. N., and Kronowitz, S. J. Pelvic, abdominal, and chest wall
reconstruction with alloderm in patients at increased risk for mesh-related complications.
Plast. Reconstr. Surg. (in press).
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