Acute otitis externa because of negative pressure wound therapy applied over the head and ear canal for scalping treatment

Abstract

Scalping is considered a complex wound with difficult treatment, requiring early surgical intervention, reconstructive plastic surgery, and a multidisciplinary team. The reconstruction of the scalp frequently requires a combination of therapies, including temporary coverage, such as negative pressure wound therapy (NPWT). Complications of NPWT, such as bleeding, infection, and pain, have been described. However, there is no report of acute otitis externa (AOE) because of NPWT. In this article, we present an unprecedented clinical case – a female patient who developed AOE after scalping treatment with NPWT applied over the head and ear canal. We consider that it may be a result of the direct physical action of subatmospheric pressure, the presence of dressing covering the external meatus, and alteration of the bacterial population.

1. INTRODUCTION

Scalping refers to full‐thickness soft tissue avulsion or removal of the calvarium. A major cause of scalping is trauma is scalping. It is considered a complex wound with difficult treatment, requiring early surgical intervention, reconstructive plastic surgery, and a multidisciplinary team.1, 2 The reconstruction of the scalp frequently needs a combination of therapies, including temporary coverage.1, 3, 4

One technique of temporary coverage is negative pressure wound therapy (NPWT).4 It is a method of injury treatment that applies subatmospheric pressure to the surface of a wound.5

Complications of NPWT have been described, mainly represented by bleeding, infection, and pain.6 However, there is no report of acute otitis externa (AOE) because of NPWT. In this article, we present an unprecedented clinical case, a female patient who developed external otitis after scalping treatment with NPWT applied over the head and ear canal.

2. CASE REPORT

A 31‐year‐old woman was injured with agricultural equipment that pulled her hair, causing total scalping and partial avulsion of the left ear. The cleavage plane of the scalp occurred mainly in the areolar layer, separating the tissue into skin, subcutaneous tissue, and galea superficially and pericranium and calvarium deeply. There was also a segment of 15 × 9 cm of disruption of pericranium, which was absent at the temporoparietal region with bone exposure.

After life support measures and initial trauma procedures, scalp reimplant with vascular anastomosis was initially attempted. Because of vascular thrombosis and congestion, necrosis of reimplanted tissue occurred.

On the 5th day after trauma, the necrotic tissue was debrided, the outer sheet of the bone was drilled, and NPWT was installed (Figure 1). The Vacuum Assisted Closure (VAC, KCI, San Antonio, Texas) system, configured to 125 mm Hg of continuous suction, was used. The plan was to provide temporary coverage while the wound bed was prepared. Next, definitive reconstruction would be performed with a combination of the acellular dermal matrix (Pelnac, Gunze Limited, Tokyo, Japan) and split‐thickness skin graft. After 7 days of debridement, the dermal matrix was installed above the multi‐perfused calvaria (to the diploe layer),7 and NPWT was maintained over it to accelerate granulation tissue and matrix integration (Figure 1).

Figure 1.

Upper, left: Scalping lesion after debridement; upper, right: negative pressure wound therapy (NPWT) covering both ears; lower, left: NPWT covering right ear canal; lower, right: NPWT covering left ear canal

As the area of the lesion involved both ears, including avulsion of the left ear, the dressing encompassed the left external acoustic meatus. Initially, the patient tolerated this strategy well, presenting mild otalgia controlled by simple analgesia, without hearing loss, tinnitus, or ear fullness.

After 16 days of debridement and NPWT, the otalgia became refractory to analgesics. The dressing was removed, and complete ear evaluation was achieved while the patient was anaesthetised, which included otoscopy by an experienced otolaryngologist. AOE was then diagnosed, and NPWT was contraindicated. As a result, the wound was enclosed with bandages that also covered the auditory canal, as previously performed. The patient was treated with intravenous ciprofloxacin, and the symptoms ceased after the interruption of the NPWT.

Definitive treatment for scalping was then implemented with the split‐thickness skin graft above the proper wound bed (Figure 2). The patient presented a good clinical evolution, and the skin grafts had an appropriate integration (Figure 3).

Figure 2.

Left: Wound bed preparation after negative pressure wound therapy (NPWT) treatment; right: split‐thickness skin graft over scalping lesion

Figure 3.

Six months’ postoperatively, with stable coverage of the scalping lesion

3. DISCUSSION

Total avulsion of the scalp remains a challenging and defying wound. It is mandatory to offer trauma life support measurements, repair vessels injuries, and restore blood.8, 9 After adequate resuscitation, free tissue replantation is considered the first choice for reconstruction.10, 11, 12 As performed in this case report, if replantation is not viable, a feasible option may be the use of a dermal regeneration matrix followed by delayed split‐thickness skin grafting.13 (Figure 2) Besides the definitive reconstruction, temporary coverage is often necessary to prepare the wound bed, with NPWT being an optimal choice.4

NPWT is a system that usually consists of reticulated foam covered with an adhesive drape. Evidence suggests that wound healing is achieved by several mechanisms, which include: facilitating fluid efflux removal, reducing peripheral oedema, improving blood supply, approximating the edges of the wound, eliminating necrotic tissue, stimulating the formation of granulation tissue, and stimulating the expression of healing‐related factors, and it is proposed that bacterial clearance may occur.5, 14, 15

Significant complications of NPWT are infrequent and have already been described. These include mainly bleeding, infection, and pain. However, life quality deterioration and anxiety, rupture of heart, and death have also been described.6 In our research, we have not found any reports of otitis externa because of NPWT.

AOE is an inflammatory disorder of the external ear canal, mainly caused by bacterial infection. The Gram‐negative bacteria Pseudomonas aeruginosa is the most frequent causative organism. The main predisposing factors are local trauma and exposure of the skin to water. Diagnosis is made using typical history and direct observations of the ear canal, which presents with diffusely swollen, extremely tender, and shiny skin.16, 17, 18 The treatment involves avoiding the causative agent and empirical use of topical antibiotics, with ciprofloxacin being the first choice. Because of the necessity of dressings that covered the affected ear, we used intravenous instead of topical antibiotics.

In this case report, the cessation of otalgia after discontinuation of NPWT demonstrates that NPWT was the cause of the symptoms of AOE. Despite the absence of NPWT, the ear canal was still covered with bandages, and yet, the symptoms ceased. Therefore, we believe that the mere presence of external bodies covering the ear canal may not explain the symptoms in this case. In addition, as the symptoms ameliorated rapidly, before the action of the antibiotic, the role of NPWT as the causative agent of AOE is reinforced in this case. These observations together corroborate that NPWT may cause external otitis when it is used in head wounds encompassing the ear.

It is well known that AOE is associated with bacterial proliferation in the ear canal.16, 17 As the suction system continuously removes exudate, it is speculated that the NPWT may promote bacterial clearance and control its proliferation in the wound bed.19, 20, 21 Hypothetically, the degree of infection would be diminished by NPWT, but there are no prospective randomised controlled trials confirming these data.6 The role of NPWT in microorganism populations is still controversial, and few studies even associate it with an elevation in bacterial count.22, 23

We speculate that, when the suction is not active for any reason – for instance, when there is seal disruption of the adhesive surface or when an intermittent suction configuration is chosen, the reticulated foam of the NPWT system may act as a foreign body and as a source of infection. In this case report, the seal was disrupted three times because of the displacement of the adhesive surface, which was identified by an alarm of NPWT unit therapy. The leakage was corrected using a patch of an adhesive film. Although the correction is performed rapidly, it is difficult to precisely assess for how long the disruption occurred. Even when trying to keep the environment as sterile as possible, minimal exposure of the sponge may occur, which may increase the risk of infection.

4. CONCLUSION

Our unique and unprecedented observation suggests that NPWT applied over the ear canal may cause AOE. We consider that it may be a result of the direct physical action of subatmospheric pressure, the presence of dressing covering the external meatus, and alteration of the bacterial population.

Castro JCD, Coltro PS, Jorge JLG, Farina Junior JA. Acute otitis externa because of negative pressure wound therapy applied over the head and ear canal for scalping treatment. Int Wound J. 2019;16:559–563. 10.1111/iwj.13012