Fascia Biosystems - Preserved Particulate Fascia Lata for Soft Tissue Augmentation: A Review and Early Results of Comparative Studies Using Bovine Collagen

Preserved Particulate Fascia Lata for Soft Tissue Augmentation: A Review and Early Results of Comparative Studies Using Bovine Collagen

Amy K. Schecter, BS; Neil S. Sadick, MD, FACP, FAACS Cosmetic Dermatology 18(5): May 2005

Many fillers are available for soft tissue augmentation. Recently, preserved human fascia lata has become available in an injectable form. Prior experience using human fascia grafts has shown stimulation of fibroblasts with invasion into the graft matrix and in turn the production of new vascularized collagen. Because soft tissue defects are associated with a loss of collagen density, using preserved fascia grafts may effectively restore the lost collagen and produce longer-lasting results than the currently available collagen substitutes. We review the results of earlier studies utilizing preserved fascia grafts for soft tissue augmentation and report preliminary findings from our current investigation using preserved particulate fascia lata for the correction of nasolabial folds.

Soft tissue augmentation is commonly performed for the treatment of facial rhytides. Injectable materials have the benefit of minimal patient dicomfort, ease of procedure, and little, if any, downtime. Several biologic materials have been used to fill soft tissue defects, including bovine and human collagen, autologous fat, autologous fibroblasts, gelatin matrix, hyaluronic acid gels, micronized AlloDerm®, as well as preserved particulate fascia lata. These fillers differ in their physical properties, immunogenicity, and longevity in tissue.

Preserved particulate fascia lata (Fascian™) was introduced in 1999 for use as a soft tissue filler. The material was modeled after solid preserved fascia grafts, which have been used in surgical procedures for over a century. Preserved particulate fascia lata is registered with the US Food and Drug Administration (FDA) as a tissue product designed to replace areas of lost fascia of collagen.[1] Because the agent is a tissue product as opposed to a device, it may be used at the physician's discretion to fill soft tissue defects anywhere in the body without restriction.

Preserved human fascia initially was used as suture material[2-4] and has since become known for its safety, strength and long-term persistence when grafted into living tissue.[5] Solid fascia harvested from fascia lata and the Achilles tendon is commonly used in orthopedics for repair of the cruciate ligaments in the knee joint[6,7] and in urology for bladder suspension.[8] Preserved fascia also has been used in dural repair,[9] hernia repair,[3,5] and repair of orbital floor defects and retinal detachment.[10,11] Following its use for treating patients with facial paralysis, Gehrke[12] reported that the implanted fascia lata persisted, remaining palpable for more than 10 years.

Mechanism of Action

After implantation of solid preserved fascia, a predictable tissue reaction ensues. The graft matrix is digested over the course of several months, while simultaneous fibroblast invasion reinvests the tissue with new vascularized collagen.[2,5,13-15] The newly formed collagen undergoes a process of maturation and remodeling, which gives rise to a layer of viable scar in a similar configuration to that of the graft.

Soft Tissue Augmentation Using Solid Fascia Grafts

In 1994, solid preserved fascia grafts were introduced for the treatment of pitted acne scars.[16] Burres[16] treated 10 patients with multiple depressed acne scars that were completely healed. Chips of preserved fascia were implanted into a pocket created directly below the base of the scar, and improvement in scar contour was reported in 70% to 80% of lesions, with the greatest improvement in small, well-defined scars. However, it was noted that dark-skinned patients frequently developed areas of hyperpigmentation overlying graft sites. Occasionally, grafts were extruded through the implantation site and required reinjection.

The results of a follow-up study demonstrated increased success when the chips of preserved fascia were implanted into the substance of the acne scar as compared with below the scar.[13] This technique was found to be effective for elevation of ice-pick scars in addition to shallow acne scars.[13]

In 1998, a similar procedure was used to treat 18 patients with posttraumatic facial scars.[14] After 24 weeks, clinical improvement was graded as 75% to 100% in one third of the treated lesions and 50% to 75% in one half of the lesions. Biopsies of selected treatment sites were taken at 6 weeks and 12 weeks after implantation. Results of histologic examination of the 6-week biopsy specimens demonstrated a lymphocytic inflammatory response surrounding and invading the graft material. Specimens taken at 12 weeks demonstrated preservation of the graft, as well as fibroblast infiltration of the graft matrix. The earlier inflammatory response had resolved. Although new collagen investment of the graft material is not evident at 12 weeks, the fibroblast infiltration was thought to represent early "recollagenation."[13,14,16]

Preserved Particulate Fascia Lata for Injection

Recently, preserved human fascia has become available in an injectable particulate form designed for use as a soft tissue filler. This material may be implanted into any defect (eg, scars, wrinkles, folds) that would otherwise be treated with the currently available injectable collagen substitutes. Preserved particulate fascia lata is also appropriate in cases of prior allergic reaction to other collagen substitutes.

Graft Processing And Safety

Graft material is derived from human gastrocnemius fascia or tensor fascia lata. The human cadaver donors of this tissue are prescreened according to American Association of Tissue Banks standards.[17] The harvested tissue is prepared in accordance with FDA guidelines for processing of nonviable human tissue. After processing, the material is freeze-dried and then secondarily sterilized with gamma radiation or ethylene oxide. The graft is then particulated, loaded into syringes for distribution, and vacuum sealed.

Whenever human cadaveric material is considered for transplantation, safety is the primary concern. The presence of DNA particles has been reported in preserved fascia grafts as in many other banked tissue products. Rare cases of viral transmission have been reported following transplantation of fresh frozen cadaveric material[18]; however, there have been no such reports associated with the use of preserved fascia lata that has been processed according to FDA regulations. Because the preservation process for cadaveric fascia lata kills all viable cells, viral pathogens cannot survive and therefore cannot be transmitted in the freeze-dried tissue explants. Although transplantation of human tissue products also carries the risk fo transmission of prions, there have been no reported cases of prion transmission associated with preserved fascia lata grafts.

Unlike bovine collagen, which has an allergic reaction rate of 2% to 3%, there is no documentation of a true allergic reaction to preserved particulate fascia lata. In addition, there have been no reports of adverse effects such as infection or toxicity related to the graft material.

Surgical Technique

Preserved particulate fascia lata is supplied as a dried powder in a sterile syringe. The material is available in particle sizes ranging from 0.08mm, which may be injected through a 25-gauge needle, to 2.0mm, which may require a 14- or 16-gauge needle. Prior to injection, preserved particulate fascia lata is hydrated with 1.5 to 3.0 cc of 0.5% or 1.0% lidocaine with 1:100,000 epinephrine or with normal saline. It is recommended that the material be hydrated with the smallest volume of fluid necessary to facilitate injection through the needle.

The site of implantation should be properly anesthetized with lidocaine with epinephrine. To effectively correct a defect, the graft material must be injected precisely into the plane of soft tissue deficiency.[19] Therefore, when correcting dermal defects, intradermal needle tunneling and threading is the suggested technique for implantation.[15] The defect is undermined using a hypodermic needle, dividing bands of scar tissue, and releasing attachments. This process creates an expandable intradermal pocket into which the suspension is injected. Any material injected below the dermis will disperse into the fat and is wasted. The material should overcorrect the defect, since the hydrating solution will be absorbed slowly, leaving the graft in place. Following injection, the patient's head should be elevated and cold compresses may be applied. Minor bruising may occur.

Prior Experience with Preserved Particulate Fascia Lata

Burres [20] studied the clinical response to preserved particulate fascia lata for deep soft tissue augmentation in 81 patients. In most cases, the preserved particulate fascia lata was injected for lip augmentation. Other injection sites included the cheeks, nasal bridge, nasolabial folds, thighs, buttocks and glabella. Subdermal injections were performed for skin augmentation to enhance volume, and injections for lip augmentation were either intramusclar or submucosal.[20]

After injection, the rehydrating fluids were absorbed slowly so that the resulting volume was similar to that of the dehydrated material. Patients noted firmness of the area for the first 1 to 2 months after injection. In most cases, the graft material was persistent at 3- to 4-month follow-up, and patients were reported to be quite satisfied with the results. No postinjection allergic reactions or complications were reported.[20]

The persistence of the grafts at 3 to 4 months after injection shows promise for the use of preserved particulate fascia lata for soft tissue augmentation. Because most injections performed by Burres[20] were for lip augmentation, it is impossible to know how preserved particulate fascia lata may react when injected into the skin. Studies using other injectable fillers have reinforced the need for accurate placement of the material into the appropriate levels of the dermis and subcutaneous tissue. Further research is needed to determine the longevity of preserved particulate fascia lata following injection into the skin.

Current Developments

Sadick [21] is currently studying the efficacy and longevity of preserved particulate fascia lata for augmentation of the nasolabial folds. By injecting one side of the face with preserved particulate fascia lata and the other side with Zyplast®, the clinical effect of preserved particulate fascia lata can be compared with that of collagen, which is currently the treatment of choice in the United States.[22] Subjects are being followed for a period of 6 months, and serial biopsies are being used to quantify the length of time that preserved particulate fascia lata persists in living tissue.[21]

Preliminary results are promising with equal or greater improvement of nasolabial folds injected with preserved particulate fascia lata compared with collagen.[21] It is too early to know how long the preserved particulate fascia lata will last in tissue; however, it is hoped that preserved particulate fascia lata will stimulate fibroblast invasion in a manner similar to that seen in solid fascia grafts. By inducing the production of endogenous collagen, preserved fascia grafts have the potential to produce long-lasting tissue augmentation.[21]