augmentation rhinoplasty with siicone implant covered with acellular dermal matrix

CE: A.B.; SCS-16-0858; Total nos of Pages: 4;

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ORIGINAL ARTICLE

Augmentation Rhinoplasty With Silicone ImplantCovered With Acellular Dermal Matrix

Man Koon Suh, MD,� Kyo Ho Lee, MD,y Aram Harijan, MD,z Hyung-Gu Kim, PhD,§

and Euicheol C. Jeong, MD, PhDjj�

Copyright © 2016 Mutaz B. Habal, MD. Unauthorized reproduct

From the �JW Plastic Surgery Center; yCBK Plastic Surgery Clinic; zWellPlastic Surgery Clinic, Seoul; §L&C BIO Co/R&D Center, Seongnam;jjDepartment of Plastic Surgery, SMG-SNU Boramae Medical Center;and �Department of Plastic and Reconstructive Surgery, College ofMedicine, Seoul National University, Seoul, Korea.

Received June 14, 2016.Accepted for publication August 27, 2016.Address correspondence and reprint requests to Euicheol C. Jeong, MD,

PhD, Department of Plastic Surgery, SMG-SNU Boramae MedicalCenter, 5 Gil 20, Boramae-Road, Dongjak-gu, Seoul 07061, Korea;E-mail: [email protected]

H-GK is the Director of the Research Institute in L&C Bio Co. ECJ hasreceived research grant support from L&C Bio Co. The remainingauthors report no conflicts of interest.

Copyright # 2016 by Mutaz B. Habal, MDISSN: 1049-2275DOI: 10.1097/SCS.0000000000003225

The Journal of Craniofacial Surgery � Volume 00, Number 00, Month 2016

Background: Alloplastic materials are a mainstay in Asian rhino-plasty. However, the outline of alloplastic implants can becomeconspicuous over time in rhinoplasty patients, which is a significantcause for revision. In revision rhinoplasty, alloplastic materials canremain a viable and affordable option in Asian patients. Theacellular dermal matrices (ADM) are often used to interfacebetween the silicone material and the skin envelope. This studyassesses histologic changes following implantation of ADM-cov-ered silicone material in rats.Methods: To demonstrate differences at the histologic level,silicone blocks with and without ADM were implanted in thesubcutaneous plane of 10 rats. These implants were harvestedafter 9 weeks and examined histologically for capsule thicknessand myofibroblast activity.Result: In the in vivo study, the presence of ADM was associated withsignificantly decreased capsule thickness and myofibroblast activityaround the implant and maintained the structure of ADM well.Conclusion: The authors suggest that using the ADMs to coversilicone implants can be an alternative method for decreasing thevisibility of implant contour, by the prevention of capsular contractureand the addition of a soft tissue layer to the dorsal skin envelope.

Key Words: Acellular dermal matrix, alloplastic implant, Asian

rhinoplasty

(J Craniofac Surg 2016;00: 00–00)

n Asian rhinoplasty, dorsal augmentation is a popular method for
I addressing the characteristic appearance of a low profile and deficienttip projection. The nasal skin envelope is known to be thicker amongAsian patients, and alloplastic implants are more frequently used thanamong Caucasian patients.1–3 However, dorsal augmentation with analloplastic implant sometimes causes complications, such as infection,
contracture, mobile implant, deviation, visibility, transparency, andnasal tip ulceration with associated extrusion.4

Of these complications, implant visibility is caused by theobliteration of the dorsal esthetic lines, which is replaced by thestraight contour of the implant itself. Additionally, an extremelythin envelope might be transparent enough to allow direct vision ofthe implant and capsule color and texture beneath the skin. Theproblem of implant visibility is more common in Caucasianpatients, but can also be observed in Asian patients with increasingfrequency. In addressing this problem, autogenous tissue is the mostpopular and reasonable option in revision rhinoplasty. However,alloplastic materials continue to be investigated and considered inthe setting of revision rhinoplasty.5,6 Among various materials,silicone implants are frequently used for biological stability andease of carving to the appropriate configuration.1–4 The humanacellular dermal matrix (ADM) has also been used recently as thewrapping material for diced cartilage graft and other alloplasticimplants.5–7 In this study, we characterize the utility of ADM inminimizing capsule formation on the implant and adding a collagenlayer through an animal experiment.

MATERIALS AND METHODS

Animal and Implant MaterialThroughout the course of this study, the authors followed the

‘‘Animal Research: Reporting In Vivo Experiments’’ guidelines.Upon ethics approval from the committee on animal experimen-tation at Boramae Medical Center (Study No 20130026), 10Sprague Dawley rats were obtained (weight range 320–330 g).The animals were an acclimation period of a week with unrestrictedaccess to water and feed.

Human cadaver ADM (Megaderm, L&C Bio, Seoul, Korea) wasobtained in a prepackaged form with 2 thickness, 0.7 and 1.5 mm.Medical-grade thick silicone sheets of 3-mm thickness wereobtained, cut into 10� 10 mm2, and sterilized in an aseptic packageprior to experimentation.

Implant PreparationThe study was designed such that each rat was implanted with

each 10� 10 mm2 of the following: silicone only, 0.7-mm ADM/silicone, 1.5-mm ADM/silicone, and ADM only (1 layer of3.0 mm). The ADM-silicone implants were prepared by cuttingrespective ADM sheets into size and by suturing the ADM sheets tosilicone using 5-0 polypropylene sutures (Fig. 1A). The ADM-containing implants were allowed to hydrate during the surgicalpreparation of the rats.

Implantation and HarvestThe rats were anaesthetized by the intraperitoneal injection of

a mixture containing 20 mg/kg of Zoletil (Virbac, France) and2 mg/kg of Rompun (Bayer Korea Corp, Seoul, Korea). The backwas shaved and subsequently washed with povidone–iodine

ion of this article is prohibited.

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FIGURE 1. (A) Preparation of an acellular dermal matrix (Megaderm, L&C Bio,Seoul, Korea)-covered silicone implant. (B) The implants are inserted into 4separate subcutaneous pockets on the dorsum of each rat, as described in the‘‘Methods’’ section. (C) Each implant was loosely adhered to the panniculuscarnosus layer without gross changes at the 9th week. (D) En-block excision ofeach implant at 9th week.

TABLE 1. Thickness of Capsular Fibers Surrounding Silicone Implants

Silicone Implants

Test Animal No ADM 0.7-mm ADM 1.5-mm ADM

1 210 103 85

2 253 116 100

3 217 85 75

4 187 100 113

5 213 83 116

6 167 90 86

7 183 123 67

8 163 70 85

9 183 110 90

Mean 197.3� 28.5 97.8� 17.2 90.8� 16.2

All measurements are in micrometers (mm).

ADM, acellular dermal matrix.

Suh et al The Journal of Craniofacial Surgery � Volume 00, Number 00, Month 2016

solution. Four subcutaneous pockets were created with thefollowing designation: A and B for the right and left upperback and C and D for the right and left lower area (Fig. 1B).Each of the pockets was made through a respective 2-cmincision. Care was taken not to allow communication betweenthese spaces.

In pocket A, the silicone implant without ADM was placed. The0.7- and 1.5-mm ADM/silicone implants were placed into pocketsB and C, respectively. The orientation was such that the exposedsilicone surface was in contact with the wound bed and the ADMsurface toward the skin. In pocket D, the ADM-only implant wasplaced. Incisions were closed with 5-0 nylon sutures.

At 9 weeks after implant placement, the animals were eutha-nized. The dorsal skin was raised as a single flap in the caudal-to-cranial direction (Fig. 1C). Each implant was harvested with asurrounding layer of connective tissue and individually fixed in 10%formalin solution (Fig. 1D).

Histological ExaminationFormalin-fixed specimens were cut into 4-mm-thick sections

and treated with hematoxylin and eosin (H&E) and a-smoothmuscle stains. The tissues were examined at 100� magnificationfor H&E samples and at 400� for the smooth muscle stains. Thehistologic slides were then presented to a pathologist who wasblinded to the nature of each specimen and who was asked todetermine the capsule thickness and myofibroblast activity.

The capsule thickness was measured from each of the H&Esamples except the 3-mm ADM-only specimen from microscopereticles calibrated with a 0.01-mm-stage micrometer slide. Myofi-broblast activity was graded by the intensity of the a-smooth musclestains. A total lack of staining was graded as 0; sparse staining as 1;mild staining as 2; moderate staining as 3; and intense staining as 4.Both of these findings were measured or evaluated in 3 separatelocations in each sample and reported as an average value.

Statistical AnalysisThe in vivo study of the animals, capsule thickness, and myofi-

broblast activity were expressed as mean� standard deviation.Statistical analysis was performed with 1-way ANOVA and pairedt-tests. All statistical analyses were performed using GraphPad

Copyright © 2016 Mutaz B. Habal, MD. Unautho

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PRISM 6.0f (GraphPad Software, La Jolla, CA). P-values of<0.05 were considered statistically significant.

RESULTSDuring the 9-week duration between implantation and harvest, 1animal expired without any signs of infection. The implantsdetached easily from the surrounding tissue with the implant shapeentirely preserved.

On microscopic examination, in pockets A, B, and C, thespecimens contained a layer of omnidirectional dermal-like fibersbeneath the subcutaneous tissues and had indirect contact with theimplant. The former layer corresponded to the ADM that was placedon the implant, but there was a thin additional layer of wavy,parallel arrays of collagen fibers abutting the implant beneath theADM, suggesting that a capsule had formed at the layer in closeproximity to the implant. The mean thickness was 197.3� 28.5 mmin pocket A, 97.8� 17.2 mm in pocket B, and 90.8� 16.2 mm inpocket C (Table 1; Fig. 2). The capsules of pocket B and C weresignificantly thinner compared with that of pocket A (control) (1-way ANOVA test, P< 0.0001). However, the thickness of thecapsule did not differ significantly between pockets B and C (pairedt-test, P¼ 0.4371). When the extent of myofibroblasts in thecapsule was compared according to histopathologic findings, theresults showed an average of 3.8� 0.4 in pocket A, 1.9� 0.6 in B,and 1.2� 0.7 in C (Table 2; Fig. 3). These results indicate that theADM-layered implant had significantly low myofibroblast activity(1-way ANOVA test, P< 0.0001), which is a pathologic cell of ahypertrophic scar or capsular contracture, but no statistically sig-nificant difference was observed between pockets B and C, either(paired t-test, P¼ 0.0805). In pocket D, we did not find the capsulearound ADM.

DISCUSSIONIn Asian patients, silicone implants are widely used in rhinoplastybecause the material is biologically stable, resistant to degradation,easy to carve, and convenient to remove in the patient with revisionrhinoplasty.1–4

A significant shortcoming of implants is that implant visibilityvia obliteration of the dorsal esthetic line and translucency of skin inthose patients with thinner envelope.4,8–10 This is very commonamong Caucasian patients with inherently thin skin, and is observedwith frequency even in Asian patients in whom the skin envelopehas been thinned. This phenomenon is caused by host inflammatory

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# 2016 Mutaz B. Habal, MD


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FIGURE 2. Hematoxylin and eosin staining of the capsule at�100. (A) The thickcapsule in the silicone-only specimen, Pocket A. (B) Capsule in the 0.7-mm-thickADM layered silicone implant, pocket B. (C) Capsule in the 1.5-mm-thick ADM-layered silicone implant, pocket C. (D) No capsule in the 3-mm ADM-onlyspecimen, Pocket D. The omnidirectional appearance of the collagen layer ischaracteristic of ADM. Dense fibrous capsule is less thick in the ADM-layeredimplant. ADM, acellular dermal matrix.

FIGURE 3. The extent of myofibroblasts, a-smooth muscle actin staining at�400. (A) The thick capsule in silicone showed strong staining, score 4, PocketA. (B) The capsule in the 0.7-mm-thick ADM-layered silicone implant showedless staining than A, score 2. (C) Capsule in the 1.5-mm-thick ADM-layeredsilicone implant showed weaker staining, score 1, pocket C. (D) No capsules inthe 3-mm ADM-only specimen were stained, Pocket D. ADM, acellular dermalmatrix.

The Journal of Craniofacial Surgery � Volume 00, Number 00, Month 2016 Silicone Nasal Implant With ADM

response to the foreign body and formation of scarring around theimplant, leading to a thick capsule, including calcification and athinning innate dorsal tissue envelope of the nose around theimplant.8–10

To correct this visibility of the silicone implant, the best solutionin the revision surgery is to use autogenous tissues for dorsalaugmentation.4,7,8 However, the use of autologous tissue presentsits own limitations in various situations. For one, autologoussources of tissue may not provide sufficient volume of graft materialneeded for dorsal augmentation in Asian patients (eg, auricularcartilage, septal cartilage, or dermofat graft). The use of autogenousrib cartilage necessitates a second operative donor site on the torso,which is shunned among Asian patients. Absorption and warpingare additional issues to consider.4,5

In specific patients, the alloplastic implants are still used in therevision rhinoplasty.5–8,10 In using an alloplastic implant in the


TABLE 2. Histologic Grading for Myofibroblasts

Silicone Implants

Test Animal No ADM 0.7-mm ADM 1.5-mm ADM

1 4 2 1

2 3 2 0

3 4 3 1

4 4 2 2

5 4 1 2

6 3 2 2

7 4 2 1

8 4 2 1

9 4 1 1

Mean 3.8� 0.4 1.9� 0.6 1.2� 0.7

The intensity of a-smooth muscle actin served as a representation of myofibroblast

activity. 0: Complete lack of staining, 1: sparse staining, 2: mild staining, 3: moderate

staining, and 4: intense staining.

ADM, acellular dermal matrix.


revision, there are several options. Generally, the implant materialand/or style should be changed. For example, solid siliconeimplants are switched with soft implants such as Gore-Tex, andhigh-profile L-shape implants are changed to low-profile I-shapeimplants.8–11 Removing the capsule surrounding the implant isinevitable in revision rhinoplasty, which aggravates the problem ofdorsal tissue envelope already being too thin. To counter thisproblem, some surgeons use implants in conjunction with auto-logous tissue, such as temporoparietal fascia and/or pieces ofcartilage to achieve a smooth implant profile by adding alayer.12–14 However, debates still exist over the long-term dura-bility of used alloplastic implants in rhinoplasty related to thebiologic response.

ADM is produced from human cadaveric skin. The cellular andimmunogenic components of the skin are removed, leaving behindthe basement membrane and cellular matrix. Studies have shownthat this matrix acts as scaffolding, which leads to cellular integ-ration into the surrounding tissue.15 In rhinoplasty, it is used foradding height to the nasal dorsum, camouflaging minor irregula-rities, and thickening the nasal dorsal skin.16 Gordon et al7 usedADM as a framework material for wrapping diced cartilage invarious saddle nose deformity with few complication and accep-table results. The clinical characteristic of ADM would bebeneficial for making a smooth profile implant, as with the auto-logous dermis or fascia, and ADM has already been used in thismanner.5–7 In the experience of authors, clinical outcomes werealso favorable (Figs. 4 and 5). Among various operations involvingalloplastic implants, using ADM to partially cover implant or tissueexpender has become very popular in reconstructive breast surgery.In our in vivo study, the ADM-covered silicone developed rela-tively little of the parallel, wavy collagen fibers—the histologicfinding of capsular formation. More superficial than this capsularfiber, the specimens contained a layer of omnidirectional dermal-like fibers typical of ADM. Such histological features have beenreported in past studies in which ADM was found to be incorporatedby the host tissue with evidence of cellular repopulation andrevascularization.17,18

The presence of ADM was also associated with a significantlylower density of myofibroblasts, which corresponds with clinical


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FIGURE 4. (A) The ADM (Megaderm, L&C Bio, Seoul, Korea) (above) and thecarved silicone implant (below); size of the ADM is 0.7 mm�5 cm�1.2 cm. (B)The silicone implant was fixed with ADM using absorbable sutures, which will beused in the rhinoplasty. ADM, acellular dermal matrix.

Suh et al The Journal of Craniofacial Surgery � Volume 00, Number 00, Month 2016

reports regarding the decreased rates of hypertrophic scarring andcapsular contracture when ADMs are used in conjunction withsilicone implants. The results of our experiment are in generalagreement with a primate model of ADM-covered tissue expander,in which the presence of ADM was found to significantly decreasethe amount of capsular fibers around the tissue expander.18 How-ever, the authors found that the thickness of ADM did not cause anydifference in capsular thickness or myofibroblastic activity.

This study shifts the burden of proof back to the clinical arena todetermine whether such histologic changes are significantly associ-ated with implant visibility from the thick capsule and thin dorsal


FIGURE 5. A 52-year-old woman who reported a noticeable and visible nasalimplant caused by previous silicone augmentation rhinoplasty. A 4-mm-thickboat-shaped silicone implant and the surrounding capsule were removed. Thenew silicone implant, which had a similar profile to the previous one, covered withacellular dermal matrix was used in the revision rhinoplasty. (A, B) Preoperativefrontal and lateral views; (C, D) postoperative frontal and lateral views 1 year later.She underwent additional blepharoplasty before the revision rhinoplasty.

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skin envelope in rhinoplasty. The authors believe that ADM wouldbe beneficial in conjunction with silicone implants as well as otheralloplastic implants. In primary rhinoplasty operations, this con-struct would decrease the possibility of unnatural implant visibilityin the long-term period when compared to that of alloplastic implantalone. However, additional expenses for the ADM material shouldbe considered.

CONCLUSIONWhen the silicone implant is used for rhinoplasty, the concomitantuse of ADM has the potential to decrease the implant visibility,especially for patients with thin skin envelops. In our study, thepresence of ADM was associated with significant decreases incapsule thickness as well as in myofibroblast activity comparedwith silicone-only implantation. Better outcomes with low compli-cation incidence are expected in follow-up observations.

ACKNOWLEDGMENT

The authors thank Dr Sohee Oh for statistical analysis in thepreparation of this manuscript.

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augmentation rhinoplasty with siicone implant covered with acellular dermal matrix

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