Neck Contracture Release With Matriderm Collagen/Elastin Dermal Matrix

Neck contracture postburn is one of the most difficult burn sequelae to manage. Poor long-term results can follow even extensive release. Disappointing results with split-skin grafting seem to have their roots in 3 phenomena—the natural contractile tendency of grafts, the pain of release that reduces exercise and splintage compliance while the grafts are in their most contractile phase, and the presence of a vestigial remnant of the panniculus carnosus, the platysma.

The effects of this latter structure are tacitly acknowledged but have not been appropriately explained.¹ Surgeons understand that the panniculus carnosus is a thin muscular layer deep to the skin, within the adventitial tissue of hair-bearing mammals. It is vestigial in humans, remaining as the platysma (with its contributions to risorius and other facial muscles), the dartos muscle of the scrotum, the corrugator cutis ani, the subareolar muscle around the nipple, and the (sometime) palmaris brevis muscle in the hand. In humans, the majority of the panniculus carnosus has been lost with evolution (along with most of our hair) leaving a poor substitute, the fatty panniculus adiposus. In this respect, we resemble the cetacea and domestic pig.²

It is likely that it has an important function in nature, which is illustrated by the pathological events during human postburn neck contraction. In a study in which 5 × 5 cm wounds were surgically created in sheep and left to heal spontaneously, full healing took 29 days and left a final healed scar size of 1 × 1 cm (representing a 96% reduction in wound area).³ Marked contraction of the panniculus carnosus occurred within a few days of loss of the overlying skin. This contraction reduces wound area and may even appose the wound edges depending on the initial size of the wound. This markedly expedites the rate of healing. Without this facility in the wild, an injured animal, whether predator or prey, would be seriously disadvantaged relative to its counterparts. The panniculus carnosus may represent a chance for survival in such circumstances. This might explain why the panniculus carnosus persists in humans mainly as a thin sheet of muscle covering the tender structures of the neck (platysma), which is the most frequently attacked site by large mammalian predators. Evolutionarily, this might have preserved life after failed attacks with rapid closure of skin over vulnerable and vital structures.²

However, rapid closure of any significantly sized wound on the neck brings with it compromise in cosmesis. The origins of the platysma, from the manubrium to acromion inferiorly and the lower border of the mandible superiorly, demonstrate the area over which this typically neglected muscle functions. Contraction, secondary to injury, unfortunately distorts the usual contours of the neck, dulling the inferior mandibular border, obscuring normal surface anatomy, and blunting the cervicomental angle. Complete excision of the platysma to restore neck cosmesis is not a new concept and has been advocated previously.¹

Obviously, complete excision of platysma necessitates reconstruction of the neck. Typically, this is achieved by split skin grafting, although poor long-term results with reoccurrence of the contracture appear inevitable.

The frustration of surgeons with poor results following skin grafting has led to a stream of alternative maneuvers, which have included large local flaps and free flaps (with or without grafting of the secondary defect), local or distant flap raising after tissue expansion. Some of these techniques have yielded beautiful results in the literature. However, in the developed world, most neck contraction is seen in the setting of very large burn injuries where such flap options are usually limited or nonexistent.

A great deal of excitement followed the introduction of Integra dermal matrix. A material that, when used appropriately, reduces wound contraction by “transforming” a split-skin graft into a full-thickness graft by “creating” a neo-dermis. However, in neck contraction, even this strategy is difficult to employ. In the “cold” setting of burn reconstruction, Integra can take 4 to 5 weeks to vascularize during which it is vulnerable to infection and fragile to mobilization until overgrafted. Thus, some of the extent of release is lost before the grafts are applied.

A newer material, Matriderm (De Suwelack Skin and Health Care AG, Billerbeck, Germany), has been marketed recently.⁴ It is a 3-dimensional dermal matrix composed of bovine dermal collagen (I, III, and V) and bovine nuchal ligament elastin. The manufacturers claim that it can be applied into a debrided wound and split-skin graft applied immediately and that the matrix has hemostatic properties, which reduce the incidence of subgraft and submatrix hematoma. The claim of the ability for immediate application under split-skin graft has been supported by 3 small studies, although study designs precluded comparison with industry standards, like Integra.^5,6 A 1-stage dermal replacement might be able to solve some of Integra's problems.

Our patient is a male, involved in a car rollover and fire, in which he was trapped for some time. He sustained full-thickness burns to face and neck, upper anterior and posterior torso, and both upper limbs completely (35% total body surface area). He had an extremely significant inhalation injury, which necessitated 6 weeks of intensive care unit (ICU) admission, with intubation followed by tracheostomy at 2 weeks. His burns were excised from his upper limbs, chest, back and shoulders immediately on arrival (within 12 hours of his burn injury) and grafted successfully. As is our policy, the facial and neck burns were initially treated conservatively although the head burns were excised 2 days later and grafted. He developed vancomycin-resistant enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) on ICU and the development of his lower airway chemical pneumonitis precluded further acute intervention. He struggled physiologically for several weeks before being fit for discharge from the ICU to the burns unit.

He already had a degree of neck contracture by that time, but other issues were more pressing and needed intervention, such as bilateral upper and lower eyelid ectropion. His physical state precluded significant major intervention and the residual wound contamination with MRSA and VRE discouraged surgical heroism. He was transferred to our rehabilitation facility for aggressive therapy. It became obvious after a few weeks that his neck contracture was worsening. Options for release and repair were assessed. The degree of contracture (6 cm from point of chin to sternal notch) meant that the created defect after release was going to be very large and a full platysmectomy would be essential (Fig 1). He had no free flaps capable of closing such a defect and no local tissue suitable for expansion. The tension in the neck had caused breakdown of chest and cheek scars, which were MRSA/VRE contaminated, meaning that a 2-stage Integra procedure would be foolish. However, a release was needed that would be more sustainable than split-skin grafting alone.

Figure 1. Preoperative view of the neck contracture.

Matriderm has recently been released onto the global scene although it is not yet registered with the Therapeutic Goods Administration for use in Australia. The offer of a 1-stage dermal matrix and grafting option was appealing, since earlier healing would avoid infective problems and the use of vacuum-assisted closure (VAC) device, as a dressing would allow conformation of material and graft. Following purchase and requisite approval, the operation was scheduled.