Biodegradeable temporising matrix use in a traumatic chest wound

Abstract

The Welsh Centre for Burns and Plastic Surgery is responsible for a population of 10 million people in Wales and England. We describe the use of biodegradable temporising matrix (BTM) in a large traumatic chest wound in a 23-year-old woman. BTM is a synthetic dermal substitute and has been utilised to achieve soft tissue coverage in complex wounds. This wound was sustained after the patient fell from a tractor into a large silage rake, resulting in injuries to her chest and limbs. Following meticulous debridement, her resulting full thickness skin defect measured 30 × 30 cm extending from the sternal notch to the upper abdomen, with bone, muscle and breast tissue exposure. The central chest area is complex to reconstruct due to the contours of the breasts and tendency to contracture following skin graft reconstruction. We demonstrate the first reported use of BTM for breast reconstruction, as far as we are aware.

Background

We present a case of the reconstruction of a complex farmyard contaminated chest wound involving exposed bone and breast tissue using biodegradable temporising matrix (BTM). As far as we are aware this is the first use of BTM for tissue reconstruction overlying breast. BTM is a completely synthetic dermal matrix used for wound reconstruction, consisting of a layer of novosorb foam 2 mm thick with a non-biodegradeable polyurethane sealing membrane.¹ Reconstruction using BTM involves a two-stage process. During the first stage, the matrix is secured to the base of the wound, in this case using staples. This allows fibroblasts and endothelial cells to grow into the matrix, generating a neodermis and allowing vascularisation. The sealing membrane overlying the matrix takes on the role of the epidermis, preventing loss of moisture and therefore wound contraction.² The second stage can occur once the matrix is vascularised. The sealing membrane is delaminated and a split skin graft is applied. Over the subsequent 12 months, the biodegradeable polyurethane foam breaks down via hydrolysis without any production of toxic products.¹

BTM has been tested with good effect in animal models, and subsequently in free flap donor site reconstruction, necrotising fasciitis reconstruction and acute burns, as well as in other settings.^2–5 Prior to application of the BTM, the wound must be meticulously debrided as an infected wound bed would result in the dermal matrix being removed.

Case presentation

Presented is the case of a 23-year-old woman with a body mass index (BMI) of 22 who attended via air ambulance to the emergency eepartment in Morriston Hospital following a farming accident with severe life changing injuries. These were sustained after the patient fell from a tractor and was then run over by a large silage rake. This resulted in significant soft tissue injuries to her anterior chest, right forearm, both knees, left medial ankle and forehead (10% total body surface area (TBSA)). The most extensive defect was to her chest (8% TBSA) with significant soft tissue avulsion and dozens of deep linear lacerations exposing the sternum. The wounds were complicated by extensive agricultural contamination. The patient was managed according to Advanced Trauma Life Support (ATLS) protocols. She was initially hypotensive on arrival to the accident and emergency department and was transfused with a unit of red cells. Tranexamic acid was also administered.

Investigations

A trauma CT scan was carried out and was reported as demonstrating a fracture of the anterior cortex of the right inferior S3 sacral ala and an S3 spinous process fracture, as well as multiple foreign bodies within the soft tissue of the breasts and head with lacerations. Pulmonary contusions were additionally noted.

Treatment

Initial debridement was undertaken out of hours by a three consultant team, and once meticulous, a vacuum dressing was applied to the chest. The patient was subsequently transferred to the intensive care unit. Following initial debridement the resulting full thickness skin defect measured 30 × 30 cm extending from the sternal notch to the upper abdomen, with muscle and breast tissue exposure as well as an area of exposed sternum.

The chest wound provided a significant reconstructive challenge for a number of reasons. The wound was large in size due to the radical debridement necessitated by the farmyard contamination, with irregular contours and additional exposed bone. In addition, there were no obvious donor sites for free flap reconstruction due to the limb injuries. Female chest reconstruction is typically difficult due to the contour of the breasts and the tendency for contracture following skin graft reconstruction. The loss of skin overlying breast tissue required a pliable and aesthetically satisfactory wound coverage, with nipple preservation. BTM as a skin substitute offered a potential solution, due to its comparative resistance to infection in the literature, ability to cover exposed bone and reduced contracture in comparison to split skin graft alone.

Seven days following the initial debridement, a further debridement and closure of the limb wounds was carried out, as well as a change of vacuum assisted closure (VAC) dressing to the chest (figure 1). The chest wound was monitored for any signs of infection, and frequent wound swabs were carried out to ensure suitability for dermal matrix application. Nine days later further debridement and application of BTM under slight tension was carried out on what we consider ‘day 0’, 16 days post injury. The BTM was secured with staples to ensure maximum contact with the wound bed. The cortex of the exposed sternum was burred to promote vascularised granulation tissue.

Figure 1.

Seven days post injury, the patient underwent examination under anaesthesia, further debridement and change of dressing. The wound measured 30 × 30 cm, and areas of exposed sternum and breast tissue are visible.

Change of VAC dressing on day 5 demonstrated good adherence of the BTM. During a further dressing change on day 12 the BTM showed good signs of integration into the wound bed. Nearly 4 weeks later on day 39, the impermeable layer covering the BTM which temporises the wound was delaminated with ease and a split thickness skin graft was applied from the right thigh.

As well as treatment from the surgical team, the patient additionally received support from an extensive multidisciplinary team. She was seen extensively by the physiotherapy team as an inpatient due to the risk of contracture. They worked on strengthening her core, as well as back and scapular muscles to maintain an appropriate posture, and appropriate scapular retraction. They also worked on maintaining her range of shoulder movement through a variety of exercises.

The patient was also reviewed by the psychology team due to the traumatic nature of her injuries. She engaged well with the psychological support offered to her both as an inpatient and an outpatient. In initial psychology review she described a normal trauma response in terms of running through the accident in her mind in the first few days of admission, trying to ‘make sense’ of it all and thinking through the ‘what-ifs’ of the situation. Common reactions to traumatic events were discussed with the consultant clinical psychologist and she responded well to psychoeducation. Discussions around approaching the scene of the accident in a graded way when returning home, which she had some understandable concerns about, were also covered.

While an inpatient a joint meeting was held with the patient between psychology, occupational therapy and the surgical team to discuss the extent of her injuries and treatment plans. She was well supported at home by her family and long-standing boyfriend and on outpatient review she described adjusting well to being at home with no significant post trauma symptoms being evident. Looking at her wounds needed to be approached with care and the patient managed this well with the support of the multidisciplinary team. The patient engaged well with the outreach team with no longer term psychological support being required.

Outcome and follow-up

The patient was seen in outpatient clinic on day 117 (figure 2). The wound had healed well and was malleable with the patient having no restriction in movement of her shoulders. The patient had returned to work. She was followed up extensively in the community by the physiotherapists who continued to encourage her to maintain good posture and range of movement, as well as the clinical psychology consultant. She has also been followed up by the occupational health team, who have provided advice on scar management. At 12–18 months when the wound reaches maturation, alternative therapies including laser therapy could be considered. The patient now has no functional issues, and the skin is supple and malleable. The remaining issues are of a cosmetic nature, as although the centre is pink and flat hypertrophic edges remain around the edge of the wound.

Figure 2.

The result on day 117 on outpatient review.

Discussion

Aesthetic recontouring is always paramount during breast reconstruction due to the potential psychological implications of contour deformity in female patients.⁶ A dermal matrix in the form of integra has previously been used with success for soft tissue reconstruction overlying the breast. Twelve female patients underwent reconstruction of previous burn scars to the breast with integra. All experienced improvement in breast contour, and only one patient experienced contracture of the graft site. Pliability was generally comparable to normal skin 6 months postoperatively.⁷ Therefore, a successful precedent had been set for the use of a dermal matrix in the reconstruction of breast wounds.

BTM has demonstrated comparable reconstructive outcomes to integra,^2–5 but is synthetic and therefore carries a reduced risk of infection. In a comparative study to integra in porcine models, BTM showed superior resistance to infection.⁸ Therefore, due to the history of agricultural contamination, BTM was the most appropriate means of meeting the reconstructive challenge posed by this patient.

Skin following BTM reconstruction is pliable and has shown resistance to skin contracture, including in persistently moving areas such as the neck.³ Pliability and resistance to wound contracture is essential in achieving the desired result of an aesthetic breast contour, and BTM compares favourably in aesthetic terms with other reconstructive options. In a case series of necrotising fasciitis debridement reconstruction, the authors noted reduced wound contracture and improved uniformity of texture in comparison to previous experience with primary split skin grafting and improved contour compared with free flap cover.³

BTM has also demonstrated the ability to cover complex wound beds including exposed bone³ and tendons.⁹ In this case, an area of exposed sternum made this essential. BTM can usually be delaminated in fully vascularised wound beds in 2–3 weeks,¹ but often requires longer periods of time in non-vascularised beds.^{1 3 9} In this case due to the exposed bone, delamination and grafting occurred after 39 days.

The result of the BTM use was good breast contour, no restriction in movement at the axilla and no evidence of wound contracture. In addition, there was no infection despite a farmyard contaminated wound on initial debridement. Therefore, this case has demonstrated that BTM can achieve good outcomes in female breast reconstruction and also in severely contaminated wounds.

Patient’s perspective.

Throughout my stay I received excellent care and support from all the staff. Everybody was so kind and always had plenty of time to chat, with nothing ever too much hassle. With visiting being restricted due to COVID-19, this was much appreciated and undoubtfully helped to keep my spirits high. Every step or procedure in my recovery was fully explained which gave great reassurance and I always felt as if I was in safe hands.

Roughly 9 months on from finishing my treatment it still amazes me every day at how well my chest and scars are looking. My chest is pain free, fully flexible, getting smoother with little indentations, and the colour is getting lighter all the time due to the incredible job the doctors and surgeons did using the BTM. Remembering back to the pain and wounds I had on the day of my accident I never thought that I would have recovered so well physically with minimal visual scars.

Having experienced for only a short period of time the work and commitment given by the staff at the Burns Unit I realise how lucky we are to have the NHS and often how underappreciated the staff are. I feel so lucky to have had the BTM treatment and I will be forever grateful to the staff for their faultless care and amazing work. Thank you.

Learning points.

• Biodegradable temporising matrix (BTM) is a valuable tool for reconstruction, including for tissue overlying breasts.

• The BTM did not become infected despite application onto a previously farmyard contaminated wound.

• This case provides further evidence that BTM can cover complex wound beds including exposed bone.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).