Homologous Grafts

Homologous bone, cartilage, and dermal grafts alleviate donor site morbidity, but significant resorption has been reported. Toriumi et al.22 studied long-term resorption rates of deminer-alized bone split rib implants. The average rate of resorption after only 2 years was greater than 80%. The results obtained with homologous tissue can also be unpredictable. The surface structure of the implant material can change with time, leading to distortion of the overlying soft tissue. Despite these potential inadequacies, irradiated cadaveric costal cartilage serves as an adequate substitute for autologous rib cartilage. A number of things can be done to attempt to decrease the risk of warping and distortion. Gunter et al.13 describe the use of K-wire insertion into grafted cartilage to prevent such changes with time. Shaving equal amounts of cartilage from all surfaces of the graft may reduce the risk of graft distortion and warping. All perichondrium should be removed to further reduce the potential for cartilage distortion. Irradiated costal cartilage grafts have been used by several surgeons for dorsal nasal augmentation with success.23-25 Use of this material should be limited to the dorsum. Implantation into the mobile nasal tip has been associated with significant resorption.26

Cadaveric rib cartilage is obtained from donors who must meet the same criteria required for organ donation, such as screening for VDRL, hepatitis B, human immunodeficiency virus (HIV), tuberculosis, and slow virus testing. The selected donor rib is then exposed to < 60,000 Gy g-waves to destroy cellular and viral pathogens. These grafts are well tolerated because their relative acellular makeup illicits minimal immune response by the host.1 Cadaveric rib grafts are best reserved for elderly patients who require minimized operative time and donor site morbidity. Moreover, the rib of an older patient may be calcified, making it difficult to shape. Success of implantation and maintenance of graft volume seems to be related to site of implantation. The nasal dorsum appears to tolerate implantation well, most likely because of its relative immobility.23,25 Rib cartilage, either autol-ogous or homologous, should therefore be reserved for dorsal nasal augmentation where it has the best chance to preserve its volume with time. Longer-term studies are needed for a more accurate determination of the resorption rates of these grafts.

Acellular dermis (AlloDerm) is an excellent camouflage material that has been used as a substitute for skin grafting in burn patients.27 For rhinoplasty, the material is especially useful for covering dorsal nasal irregularities in the thin-skinned rhino-plasty patient. It has the distinct advantage of being readily available and well tolerated. There are no long-term data on the degree of implant resorption. However, if partially resorbed it may be replaced with a thin layer of scar tissue to maintain a smooth nasal dorsum.1 AlloDerm can be used as an alternative to fascia or perichondrium for soft tissue camouflage and may serve as an adjuvant in mucosal flap advancement procedures for closing septal perforations. AlloDerm may also be combined with cartilage or bone grafts to facilitate a smooth dorsal nasal contour in patients with thin skin.

How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

Get My Free Ebook

Post a comment