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removed. Histopathology did not
corroborate the suspicion for
rejection. In fact, the explanted
portion demonstrated neurovas-
cular ingrowth and recipient tissue
acceptance. Nevertheless, the irri-
tation resolved with focal excision
of the grossly inflamed area and
the eyelid maintained adequate
positioning with good prosthesis
retention.
All patients demonstrated
excellent prosthesis retention past
6 months postoperatively. Multiple
support mechanisms may achieve
lower eyelid stability with the later-
ally fixated collagen implant.
As with other spacer grafts,
the implant lengthens the vertical
dimension of the lower eyelid. 13,20
The robust lateral extra-orbital rim
anchor may contribute an addi-
tional bolster to the lower eyelid.
The extension of the implant
temporally past the lateral can-
thus is shown in Figure 4A and the
hypothesized support vectors con-
ferred by the implant are shown in
Figure 4B. McCord et al. 6,20 de-
scribed securing a small, thin Figure 3. Photomicrographs showing porcine acellular dermal collagen
graft to the lateral orbital rim to matrix removed 16 months after implantation. (A) Large elliptical portion of
facilitate lateral canthal anchoring the specimen, which is stained heavily with trichrome (trichrome stain × 1). (B)
in cases of tissue deficiency. Our Greater magnification than that of (A) showing dense wicker basket–like collag-
enous tissue, including small blood-filled vessels, representing a marked fibrotic
technique captures some of these reaction (original magnification ×31.25). (C) H&E stain showing ingrowth of small
benefits but employs a thicker blood-filled vessels at one edge of the tissue (original magnification ×125). The
and broader graft sheet placed peripheral areas of the specimen also show ingrowth of nerves (D through F:
throughout the extent of the H&E stains ×125), including a neuroma-like tangle (D).
eyelid.
The rigid collagen matrix or the subsequent sur- other allografts or autografts remains uncertain, but
rounding scar may stiffen the lower eyelid, which may we conjecture that these tissue reactions may improve
be of particular utility in cases of severe laxity due to eyelid tone.
oversized prosthetic stretching and floppy eyelid. His-
topathology of the one explant demonstrated reactive Limitations
fibrosis, neovascularization, and nerve ingrowth (Fig- The case series presented herein is primarily limited
ure 3). Similar fibrotic reactions and vascularization by its small sample size. In addition, it is retrospective
are described in animal models with porcine acellu- and non-comparative. The efficacy of the collagen
lar dermal collagen and human cadaveric acellular splint compared with conventional porcine acellu-
dermis implants, and have been hypothesized to lar dermal matrix collagen implants, as well as other
confer additional stability. 21,22,23,24,25,26,27 The difference spacer graft materials, is uncertain. Future prospective
in fibrotic reaction of porcine acellular collagen versus controlled comparative studies are warranted.

30 | GARCIA JOURNAL OF OPHTHALMIC PROSTHETICS