Evaluation of acellular dermal graft (AlloDerm) sheet for soft tissue augmentation: a 1-year follow-up of clinical observations and histological findings

OBJECTIVES

To evaluate and compare the long-term clinical persistence and histological appearance of subdermally implanted acellular dermal graft (AlloDerm) sheets and intradermal type I bovine collagen cross-linked with glutaraldehyde (Zyplast).

PATIENTS

Ten adult patients (5 men and 5 women; average age, 46 years; age range, 37-59 years) not allergic to bovine collagen.

METHODS

AlloDerm sheets were implanted surgically in a subdermal plane in one postauricular crease, and Zyplast was injected intradermally on the opposite side. AlloDerm and Zyplast implants were digitally photographed and their apparent volumes calculated at 1, 3, 6, 9, and 12 months after implantation. A specimen was removed at 3 and 12 months and examined histologically for collagen persistence, host tissue invasion, and inflammatory reaction.

RESULTS

The apparent implant volume of the AlloDerm sheets decreased during the first 6 months and then stabilized over the next 6 months. By contrast, Zyplast was progressively absorbed, with complete loss of clinical effect by 6 months. Histological analysis of implanted AlloDerm sheets demonstrated progressive repopulation of the graft with minimal inflammation.

CONCLUSIONS

AlloDerm sheets seem to provide stable soft tissue augmentation after an early period of resorption and are clearly superior to Zyplast injections for long-term, large-volume, soft tissue correction. Recommendations for clinical use include routine overcorrection, with subsequent augmentation delayed by at least 6 months.

Evaluation of acellular dermal graft in sheet (AlloDerm) and injectable (micronized AlloDerm) forms for soft tissue augmentation. Clinical observations and histological analysis

OBJECTIVES

To evaluate the histological and clinical properties of (1) subdermally implanted acellular dermal graft (AlloDerm) sheets vs intradermal bovine collagen and (2) subdermally or intradermally injected micronized AlloDerm vs type I bovine collagen cross-linked with glutaraldehyde (Zyplast).

PATIENTS

Twenty-five adult patients testing nonallergic to bovine collagen.

METHODS

(1) Stacked disks of AlloDerm were implanted subdermally behind one ear, and bovine collagen was injected intradermally behind the other. The soft tissue augmentation caused by the implants was measured by digital photography at 1, 4, and 12 weeks, and biopsy specimens of each implant type were examined at 3 months after implantation. (2) Micronized AlloDerm was injected intradermally and subdermally in 2 different locations behind one ear, and bovine collagen was injected in the same manner behind the other. The soft tissue augmentation caused by the implants was measured by digital photography at the time of implantation and at 1 and 4 weeks after implantation. All implants were examined 1 month after implantation.

RESULTS

All patients tolerated both implants well. (1) AlloDerm implants retained a higher percentage of the original implant volume than Zyplast at 1 and 3 months after implantation. Histologically, AlloDerm implants were extensively invaded by host fibroblasts without any foreign body reaction. (2) Intradermally injected micronized AlloDerm implants retained a higher percentage of the original implant volume at 1 month after implantation than intradermal Zyplast. Histologically, micronized AlloDerm implants were extensively invaded by host fibroblasts without any foreign body reaction. No significant differences were noted between subdermally injected micronized AlloDerm and Zyplast.

CONCLUSIONS

The macroscopic and microscopic behavior of subdermally implanted AlloDerm sheets and subdermally and intradermally injected micronized AlloDerm was compared with intradermally injected Zyplast. AlloDerm sheet volume persisted to a significantly (P < .001) greater degree than bovine collagen during the first 3 months after placement. Clinically, intradermally injected micronized AlloDerm volume persisted to a significantly (P = .01, .04, and .01, respectively) greater degree than intradermal Zyplast or subdermal micronized AlloDerm or Zyplast. Histologically, micronized AlloDerm and AlloDerm are well tolerated at 1 and 3 months, respectively. Host tissue incorporation with fibroblast in-growth and collagen deposition is seen in both materials. AlloDerm and micronized AlloDerm hold promise for use in facial soft tissue augmentation.

Endoscopic foreheadplasty: a histologic comparison of periosteal refixation after endoscopic versus bicoronal lift

Endoscopic brow lift techniques using temporary fixation rely on rapid readherence of the periosteum to calvarial bone. Little is known about the histologic events that occur during the early postoperative period after these procedures. An animal study was designed to compare and contrast periosteal fixation to bone and unelevated periosteum, with endoscopic and bicoronal brow lift techniques. One method of temporary fixation is the use of absorbable (polylactic/polyglycolic acid copolymer) LactoSorb screws; a histologic analysis of implanted LactoSorb screws was also performed. Sixteen rabbits underwent brow lifts; eight underwent endoscopic brow lift and fixation with LactoSorb screws without skin excision, and another eight underwent traditional bicoronal brow lift with skin excision and closure under tension. Animals were killed 1, 2, 6, and 12 weeks after the procedures were performed to evaluate the interaction of periosteum and bone and the normal, unelevated periosteum/calvarium interface at a site distant from the operative area. Histologic specimens were examined for the degree of apposition of periosteum to bone and for any fibrous or bony reaction at this interface. Histologic analysis showed various degrees of periosteal fibrosis and fixation to calvarial bone. After an initial phase of minimal periosteal adherence and moderate inflammation, the periosteum became progressively more adherent to bone in both groups, with no significant differences between treatment groups in rates of fixation. Fixation required at least 6 weeks. LactoSorb screws were surrounded by an area of mild inflammation and were progressively hydrolyzed and digested. Periosteal fixation increases over time for bicoronal and endoscopic brow lifts with minimal differences between the two techniques. With this animal model, periosteal adherence to calvarium requires at least 6 weeks with complete adherence by 12 weeks. In addition, the use of absorbable fixation screws seems to be both effective and well tolerated. The histologic changes associated with periosteal healing observed in this study suggest that permanent or semipermanent fixation may improve the accuracy and early postoperative maintenance of forehead advancement.

Autologous collagen dispersion (Autologen) as a dermal filler: clinical observations and histologic findings

OBJECTIVE

To assess the histologic behavior and clinical efficacy of autologous collagen dispersion (Autologen) in augmenting human dermis.

SUBJECTS

Adult patients of the Facial Plastic Surgery Clinic at The New York Eye and Ear Infirmary who were undergoing facial aesthetic surgery with skin excision.

METHODS

Five patients were injected intradermally with Autologen in one postauricular area and bovine cross-linked collagen (Zyplast) on the contralateral side. Patients were examined clinically for signs of infection, skin necrosis, or implant rejection/allergy 2, 4, and 12 weeks postinjection. Impressions and photographs of all implant sites were taken at all follow-up visits. Biopsy specimens of each implant were taken 4 and 12 weeks after injection and examined histologically for signs of integration, rejection, and resorption.

RESULTS

All implants were well tolerated. No identifiable differences were noted in the clinical persistence of Zyplast vs Autologen. Histologically, there was more variability in the degree of fibroblast infiltration of Autologen vs Zyplast deposits.

CONCLUSIONS

Our trial suggests that autologous collagen dispersion may represent a viable alternative to bovine collagen. Clinical persistence and histologic behavior of Autologen appear to be at least as favorable as those of Zyplast, and Autologen obviates the need for allergy testing and eliminates the possibility of disease transmission. Arch Facial Plast Surg. 2000;2:48-52

Modulation of tissue ingrowth into porous high-density polyethylene implants with basic fibroblast growth factor and autologous blood clot

OBJECTIVE

To investigate the effect of direct application of biologic materials normally present in wounds (basic fibroblast growth factor [bFGF] and autologous blood clot [ABC]) to accelerate the bony and soft tissue ingrowth into porous high-density polyethylene implants.

METHODS

We conducted a prospective, blinded animal histological study. Disks made of porous high-density polyethylene impregnated with bFGF or ABC were implanted into adult Sprague-Dawley rats in both subcutaneous and subperiosteal locations. Animals were killed and implants were harvested at 2, 4, and 10 weeks postimplantation and examined histologically for fibroblast invasion, collagen deposition, and inflammatory reaction.The results were compared with control (untreated) implants.

RESULTS

As a group, the histological results showed significantly more fibroblasts within the ABC-treated implants than control implants or bFGF-treated implants. This difference in the number of fibroblasts between ABC-treated implants and bFGF-treated and control implants was also statistically significant 2 weeks after implantation.

CONCLUSIONS

At the concentration of bFGF of 1 microg/10 microL, no acceleration of tissue ingrowth into porous high-density polyethylene implants was noted. However, when porous high-density polyethylene implants were treated with ABC, the implants were invaded to a greater degree by soft tissue, particularly in the early postoperative period (first 2 weeks). Bioactive substances associated with the coagulation and platelet cascades present in the ABC may be responsible for this accelerated incorporation of the porous implant and may have clinical implications. Arch Facial Plast Surg. 2000;2:27-33

Manifestations of AIDS in the head and neck

BACKGROUND

A significant number of patients with the acquired immunodeficiency syndrome (AIDS) are initially seen with symptoms related to the head and neck. It is becoming increasingly challenging for clinicians to accurately diagnose new lesions, considering the vast array of manifestations of AIDS in this region and their many atypical presentations. A comprehensive review is a valuable clinical tool.

METHODS

A MEDLINE search of the English language literature from 1984 to the present was done for this study.

RESULTS

Dermatologic, otologic, nose/paranasal sinuses/nasopharynx, oral cavity/oropharynx, laryngeal, and neck manifestations are reviewed. The gross and microscopic appearances of lesions are described, with particular emphasis on various presentations of the same lesion and lesions that may mimic the appearance of others. Practical treatment strategies are also discussed.

CONCLUSIONS

Accurate and early recognition of the many common and uncommon manifestations of AIDS in the head and neck is of critical importance to the timely and effective management of these patients.

p53 alteration and human papilloma virus infection in paranasal sinus cancer

BACKGROUND

Inverted papilloma (IP) of the paranasal sinus is a benign neoplastic condition that can be associated with squamous cell carcinoma (SCC). To understand the etiology of the disease better, paranasal sinus tumor specimens were examined for alterations in either p53 protein expression or genomic DNA sequence, and for infection by human papilloma virus (HPV).

METHODS

Tumor specimens were categorized as follows: benign, nondysplastic IP; IP with dysplasia; SCC arising within IP; or SCC without IP. Sections of each tumor specimen were stained for p53 protein overexpression, and mutations in exons 5-9 of the p53 gene were determined in DNA purified from all tumor samples. HPV infection was screened by degenerate polymerase chain reaction (PCR) amplification and typed by multiplex PCR and direct DNA sequencing of PCR-amplified HPV sequences.

RESULTS

Altered p53, either in genetic sequence or protein overexpression, was observed in 0 of 7 benign, nondysplastic IP specimens. A significantly higher p53 alteration incidence was observed for IP specimens exhibiting dysplasia (57%; P < 0.05) and IP specimens that were associated with SCC (75%; P < 0.025). HPV sequences were detected in 9 of 24 (38%) tumor specimens, 78% of which were of the oncogenic HPV16 strain. A significantly higher incidence (P < 0.05) of HPV infection was observed in IP tumors exhibiting dysplasia or containing SCC than in nondysplastic IPs. None of the p53-mutated tumors were infected with oncogenic HPV16.

CONCLUSIONS

These data suggest that p53 alterations and/or HPV infection are associated predominantly with IPs exhibiting evidence of dysplasia or IPs associated with SCC, but not in nondysplastic, benign IPs. In addition, an inverse correlation may exist between oncogenic HPV infection and p53 alterations in paranasal sinus tumors. The authors postulate that patients with IPs containing altered p53 may be at increased risk for SCC of the paranasal sinus.