The Use of NovoSorb BTM for Trauma Reconstruction: Illustrative Cases and a Proposed Decision-making Tool

Summary:

Achieving a functional and aesthetic reconstruction following complex trauma is a challenge. Skin substitutes, including acellular dermal matrices, and newer, synthetic options such as NovoSorb biodegradable temporizing membrane (BTM) have given the reconstructive surgeon a useful tool where autologous options have been exhausted, are inappropriate, or would present a suboptimal reconstruction. This case series describes 6 patients admitted to an urban level I major trauma center between July and December 2022. All patients underwent complex reconstructive lower limb surgery using BTM as either a primary or salvage option. In each case, this approach was chosen on a case-by-case basis where it was felt BTM would offer a reconstructive advantage, or where primary reconstructive options had been exhausted. Data were collected retrospectively from case notes. Three patients received BTM as a primary reconstructive option. BTM integrated successfully in all 3. Three patients received BTM as a salvage option. In 1, the exposed fracture site was successfully bridged, and in another, BTM was successfully reapplied over exposed fracture site where BTM had previously failed to incorporate. Although BTM is a relatively new tool in the reconstructive surgeon’s armamentarium, requiring further research into long-term outcomes, cost-effectiveness, and patient satisfaction, it can be a useful and versatile tool.

The use of bioengineered dermal templates such as NovoSorb biodegradable temporizing matrix (BTM) has emerged as a valuable option in complex traumatic limb injuries where traditional reconstructive options have been exhausted or are inadequate. Dermal substitutes reduce risk of secondary contractures compared with skin grafting alone, can rapidly cover large surface areas, and can bridge small areas of nonvascularized wound bed, including exposed bone.¹

BTM is a synthetic dermal substitute composed of biodegradable polyurethane foam and a polyurethane seal. A 2-mm neodermis is generated after the first application, allowing for skin grafting at the second stage.² BTM avoids risk of cross-species immune reactions, disease transmission, and cultural and/or ethical barriers associated with animal- or human-derived skin substitutes and seems to be more resistant to infection than other dermal substitutes.^3,4

We describe 6 complex cases in which BTM was used to reconstruct limb injuries. We suggest that in limb trauma, BTM can be used as (1) the first-choice reconstructive option, due to the properties of acellular dermal matrices and BTM specifically, or (2) a salvage option when other options have been exhausted. We propose a decision-making tool to guide the use of BTM in this context.

METHODS

We describe 6 patients admitted with complex limb trauma to an urban level I major trauma center over a 6-month period. All patients underwent reconstruction using BTM as either a primary or salvage option. The reconstructive strategy was chosen on a case-by-case basis by senior consultant orthoplastic surgeons.

Informed consent was obtained from all patients. Case histories are presented in a narrative format. Results are synthesized into a proposed decision-making tool.

RESULTS

Clinical details and treatment rationale are summarized in Supplemental Digital Content 1. (See table, Supplemental Digital Content 1, which provides a summary of patients included in the case series, including significant comorbidities and underlying injuries. http://links.lww.com/PRSGO/D567.)

BTM AS PRIMARY RECONSTRUCTIVE OPTION

Patient 1

Patient 1 sustained a multiplanar circumferential degloving injury of the left knee and proximal leg, a closed left distal tibia/fibula fracture and open midfoot fractures. After staged soft tissue debridement, negative pressure wound therapy (NPWT), and external fixation, BTM was applied. At 5 months postinjury, her skin grafts had taken and she was able to flex her knee joint to 85 degrees. (See figure, Supplemental Digital Content 2, which displays a 5-month postoperative image of a limb with BTM and grafted area seen over the anterior knee and leg. http://links.lww.com/PRSGO/D568.)

Patient 2

Patient 2 was admitted with intrabdominal injuries and a Gustilo-Anderson IIIC open left tibia/fibula fracture. The left leg was successfully revascularized, but the limb was not salvageable, and a below-knee amputation (BKA) was performed. There was insufficient skin to completely cover a BKA residuum, so BTM was applied and later grafted.

Patient 3

Patient 3 sustained bilateral soft tissue defects of the medial thighs with partial loss of adductor muscles. BTM was applied and later grafted. The left thigh split skin graft (SSG) took, but the right did not and healed by secondary intention.

BTM AS A SALVAGE CHOICE

Patient 4

Patient 4 was admitted with ipsilateral midshaft tibia/fibula and open midfoot fractures. Debridement of the dorsum of the foot resulted in a 25 × 13 cm soft tissue defect. BKA was offered but declined by the patient. “Fix and flap” surgery with an anterolateral thigh flap was attempted but failed. The underlying metalwork was exposed and became colonized with multidrug-resistant bacteria.

The metalwork was removed, the foot was immobilized in plaster, and BTM with overlying NPWT was applied. A 3 × 3 cm area of BTM directly overlying the midfoot fracture failed to integrate; however, it showed no signs of further infection. Therefore, a further patch of BTM was applied over this area 3.5 weeks after the first application. It successfully integrated, subsequent SSG took, and the patient was fully weight-bearing and walking unaided at 13 months postinjury (Fig. 1).

Fig. 1.

Patient 4 fully weight-bearing on the reconstructed left limb.

Patient 5

Patient 5 was admitted with bilateral open calcaneal and midfoot fractures with extensive soft tissue loss. Bone samples from the initial debridement grew multidrug-resistant bacteria and fungi. Definitive surgery was abandoned in place of NPWT and external fixation.

Three weeks later, the wounds had granulated, and free tissue transfer was no longer required. BTM and subsequent SSG was applied, and all wounds healed.

Patient 6

Patient 6 sustained an open right bimalleolar ankle fracture with overlying degloved soft tissues (Fig. 2). “Fix and flap” with an anterolateral thigh flap was performed at 2 weeks and was complicated by atherosclerotic and friable blood vessels. The flap failed and was not salvageable.

Fig. 2.

Distal third open tibial/fibular fracture with exposed medial malleolus fracture (arrow).

The patient declined BKA; therefore, reconstruction with BTM was attempted. He presented with infected metalwork 2 weeks after discharge, and it was removed. The BTM, however, successfully bridged the area of exposed bone (Fig. 3). SSG was applied. The patient was contactable by telephone and reported good function and wound healing.

Fig. 3.

Fully integrated BTM shown bridging exposed bone and fracture before SSG.

DISCUSSION

Traditionally, management of full-thickness wounds or wounds with exposed underlying tendon, bone, or metalwork in the distal lower extremity has demanded the application of vascularized, autologous tissue. However, the extent and anatomy of the defect, patient factors, and wound factors may limit autologous options for reconstruction. Excessive tissue bulk from free flaps can lead to difficulties wearing shoes and require subsequent thinning.⁵

Although the use of BTM in limb trauma has been described,^6–8 here, we report complex, illustrative cases with the view of describing 2 uses for BTM in this context (see Table 1). BTM can be used as a primary option for graftable wounds with additional requirements. Compared with primary SSG, BTM is not limited by donor site availability, and it leads to the formation of a neodermis,² which can improve durability to withstand contact with prostheses or footwear, and it can reduce secondary contractures and preserve joint mobility.^3,9,10

Table 1.

Summary of Recommendations When BTM Can Be Used for Major Trauma Reconstruction

Reconstructive Option	Criteria
Primary choice	For graftable defects in order to:
	Maintain range of motion across joints (patient 1)
	More robust surface required (eg, to withstand prosthesis or shoe wear) (patient 2)
	Allow underlying structures to glide (tendon, exposed muscle, and compartments) (patient 3)
Salvage option	For defects where a vascularized flap is the ideal reconstruction, but:
	Limited donor sites (patient 4)
	Poor host (patient 6)
	Patient choice (patients 4 and 6)
	Delayed reconstruction results in graftable bed (patient 5)

BTM can be a salvage option where previous reconstructions have failed and other reconstructive options are limited. We describe one case where reapplication of BTM successfully integrated where it had previously failed to incorporate. To our knowledge, this is the first time this technique has been described.

This article is limited by the small number of patients and, in some cases, limited follow-up. Patient-reported outcomes and objective outcome measures have not been collected. A comparison group has not been included.

CONCLUSIONS

This case series demonstrates that BTM is a useful resource in reconstruction of complex limb trauma. Further research is warranted to explore its long-term outcomes, cost-effectiveness, and patient satisfaction compared with other techniques.

DISCLOSURES

The authors have no financial interest to declare in relation to the content of this article. The authors received financial support from PolyNovo, the producers of NovoSorb BTM to cover this article’s processing charges.

Supplementary Material

gox-12-e6246-s001.pdf ^{(131.5KB, pdf)}

gox-12-e6246-s002.pdf ^{(6.3MB, pdf)}