In-Service Exam
Skin Grafts - Fat - Cartilage Grafts - 2003





Prior to use, testing for sensitivity to which of the following should be performed?

(A) Acellular dermal homograft (Alloderm)
(B) Botulinum toxin (Botox)
(C) Bovine collagen (Zyderm)
(D) Fat
(E) Polytetrafluoroethylene (Gore-Tex)

The correct response is Option C.

Prior to treatment, sensitivity testing to collagen should be performed in an inconspicuous location. Following intradermal injection of a test dose of bovine collagen (Zyderm), the patient should be monitored for four weeks because a hypersensitivity reaction may be delayed. A hypersensitivity reaction is defined as erythema, induration, tenderness, or swelling to any degree, with or without pruritus, that appears more than 24 hours after implantation and/or persists longer than six hours. Symptoms develop in approximately 3% of patients who receive an intradermal test dose. Collagen injections are contraindicated in these patients. Because patients may develop sensitivity to collagen even after successful prior treatment, sensitivity testing should be performed before every treatment.

Acellular dermal homograft (Alloderm) is comprised of processed acellular cadaveric dermis and can be injected without prior skin testing. Because fat is autologous tissue, sensitivity testing is also not required. Polytetrafluoroethylene (Gore-Tex) is a well-tolerated prosthetic material, and sensitivity screening is not indicated prior to its use.

Botulinum toxin should not be injected in persons who have a known hypersensitivity to botulinum toxin or to eggs and/or albumin. The rate of development of antibody-mediated sensitivity or resistance to desired effect with repeat injections is low. A minimum interval of three months between injections is recommended. Currently, there is no indication for testing before use of botulinum toxin.

References
1. Aspesos J, Muntzing MG Jr. Autologen. Clin Plast Surg. 2000;27:507-513.
2. Fagien S. Facial soft-tissue augmentation with injectable autologous and allogeneic human tissue collagen matrix (autologen and dermalogen). Plast Reconstr Surg. 2000;105:362-375.

Which of the following is the most common complication of autologous fat grafting?

(A) Contour irregularities
(B) Infection
(C) Migration
(D) Undercorrection

The correct response is Option D.

Inadequate correction is the most common complication of autologous fat grafting. This can result from inadequate graft volume initially or graft resorption following the procedure. Graft retention rates vary from 40% to 78% in patients receiving injections in the face; the greatest amount of resorption occurs along the nasolabial lines, and the least resorption occurs in the buccal fat pad. Additional grafting is recommended in those patients who exhibit an undercorrected appearance.

Contour irregularities are caused by misplacement of manipulation grafts. Graft appearance varies according to the quantity of material injected and thickness of the overlying skin.

Infection is commonly associated with violation of the oral mucosa during the infiltration process. Only 1% of patients undergoing autologous fat grafting develop Staphylococcus or Streptococcus infection at either the donor or the injection site.
Graft migration can result from excess pressure at the injection site, infiltration into areas of tension, such as scars or folds, or postoperative manipulation.

Excess correction or overcorrection may also occur, and is difficult to remedy. Because the grafts are infiltrated throughout multiple layers (many of them nonanatomic), it may be impossible to remove the grafts without disturbing the surrounding tissues.

References
1. Coleman SR. Facial recontouring with lipostructure. Clin Plast Surg. 1997;24:347-367.
2. Coleman SR. Long-term survival of fat transplants: controlled demonstrations. Aesthetic Plast Surg. 1995;19:421.
3. Fulton JE, Parastouk N. Fat grafting. Dermatol Clin. 2001;19:523.
4. Shiffman MA, Mirrafati S. Fat transfer techniques: the effect of harvest and transfer methods on adipocyte viability and review of the literature. Dermatol Surg. 2001;27:819.

Which of the following soft-tissue fillers is derived from hyaluronic acid?

(A) Dermalogen
(B) Fascian
(C) Isolagen
(D) Restylane
(E) Zyderm
The correct response is Option D.

Restylane is a cross-linked, stabilized, third-generation hyaluronic acid gel that is a byproduct of processed bacteria. Hyalform gel is also comprised of hyaluronic acid, but is culled instead from an animal-based compound. When used as soft-tissue filler, these substances provide low antigenicity, soft texture, and durability. However, they have not yet been approved for use in the United States.

Dermalogen (dermis) and Fascian (fascia lata) are homologous sources of injectable filler derived from human tissue. Isolagen is an autologous agent derived from human skin cells that consists of cultured fibroblast media with an extracellular matrix. Zyderm is an injectable filling agent derived from bovine collagen.

References
1. Apesos J, Muntzing MG. Autologen. Clin Plast Surg. 2000;27:507-513.
2. Cheng JT, Perkins SW, Hamilton MM. Collagen and injectable fillers. Otolaryngol Clin North Am. 2002;35:73-85.
3. Grossman KI. Facial scars. Clin Plast Surg. 2000;27:627-642.