A dermal substitute called urinary bladder matrix (UBM) enables new approaches to surgical reconstruction of severe traumatic avulsion injuries of the head and face—reducing reliance on skin grafts, reports a paper in the November issue of The Journal of Craniofacial Surgery. 

The use of UBM “minimize[s] donor-side morbidity, eliminates contraction, and offers a wide range of product sizes to cover a wide range of maxillofacial soft-tissue defects in a single-stage fashion,” according to the new research by Dina Amin, DDS, of Texas A & M University, Dallas, and colleagues.

UBM Aids in Rebuilding After Severe Head and Neck Trauma

Avulsion injuries of the head and neck pose difficult challenges for maxillofacial surgeons, due to the “intricate anatomy” of the regions, the lack of adequate tissues to cover the wound, and the risk of later scarring and wound contracture. Various dermal substitutes have been used to restore various types of challenging defects, such as burns and chronic wounds.

Derived from pigs, UBM is a specially engineered “extracellular matrix” that provides a biodegradable scaffolding for tissue regeneration. Covering the wound with UBM supports regeneration of the patient’s native tissues, including differentiation of normal skin and subcutaneous tissue layers. Amin and colleagues report their initial experience in using UBM to reconstruct severe avulsion injuries of the head and face.

The experience included eight patients treated at one oral and maxillofacial surgery department (Louisiana State University Health Sciences Center) between 2017 and 2020. The patients were five women and three men, average age 56 years. The scalp and lower jaw were the most frequent injury sites, followed by the upper eyelid, cheek, nose, or neck.

All patients had extensive soft-tissue injuries posing difficulties in reconstruction. The wounds averaged 48 square centimeters (19 square inches), in most cases extending down to muscle or bone.

Full Recovery in Six Months with Dermal Substitute

Amin and colleagues outline their technique of reconstruction using UBM dermal substitute, including preparing the wound, applying two layers of UBM, and dressing the wound. Frequent dressing changes continue until complete healing—complete coverage of the wound defect with new skin.

New tissue formation over the wound was observed within the second week after surgery. Average healing time was 36.5 days, with a range from 14 to 90 days. Although the healing process was “time-intensive,” all patients achieved complete healing within six months.

The article includes illustrative descriptions of two cases, including the reconstructive challenges faced and the outcomes achieved. “The utilization of UBM enabled us to effectively treat these wounds, resulting in the restoration of skin texture, color, and tissue thickness,” the researchers write. By avoiding the use of skin flaps for wound coverage, it also reduces problems related to the donor site from which the flap was harvested.

Amin and colleagues believe their experience supports the use of UBM as a new and flexible option for difficult reconstructions in patients with severe head and neck injuries. “UBM can potentially be utilized as a dermal substitute in maxillofacial soft tissue reconstruction,” the researchers conclude. “Further research through randomized prospective studies is necessary to ascertain the capabilities of UBM more accurately.”