The Hanikoda Method: 3-layered Negative Pressure Wound Therapy in Wound Bed Preparation

Introduction. Negative pressure wound therapy is a widely used method of wound dressing with various commercially available brands. The authors created the Hanikoda Method (HM) for effective wound bed preparation or definite wound closure. Methods. In this case series, the authors discuss 8 different wound cases that presented to their Plastics Unit from January 2014 to June 2015. Patients with traumatic or infected wounds were selected for treatment with the HM. Selected patients underwent multiple cycles of this method until their wounds were ready for definite wound closure or the wounds had closed by secondary closure. Discussion. The purpose of any wound dressing is to encourage epithelization while ensuring no factors impede wound healing. An additional benefit is to reduce wound bed size so that it may close by secondary intention or require less skin graft coverage. Each layer of the dressing is described, along with its function in wound bed preparation or in closure. Conclusion. The HM facilitates reduction of wound size, wound bed preparation, and overall management.

Negative pressure wound therapy (NPWT) has gained significant popularity as a modality for treating difficult wounds, and the further advancement of this technique is making great inroads into wound therapy. Although its physiology and exact mechanism of action has been postulated upon, there is still ongoing research into the exact mechanisms that will help mold future NPWT application. 

The most basic NPWT performed is by using open-pore foam and a semiocclusive dressing with a tube connecting the dressing to wall suction or a suction device. Typically, the dressing is kept for 2-3 days¹ before being changed, and suction is typically set between -75 mm Hg to -125 mm Hg.²

At the Universiti Kebangsaan Malaysia Medical Centre (UKMMC), Kuala Lumpur, Malaysia, the authors developed a combination multilayer NWPT by combining hydrogel, paraffin tulle, and NPWT and named the new design the Hanikoda Method (HM). 

Developed out of necessity to help manage patients who refused soft tissue reconstruction and/or were unsuitable candidates for immediate reconstruction, the HM was subsequently applied to patients requiring wound bed preparation (WBP) who were referred to the UKMMC Wound Care Team. The HM provided an effective solution for WBP and definitive soft tissue closure in this patient population.

Patients referred to the UKMMC Wound Care Team  with wounds that required WBP to cover exposed structures, or with a high degree of fibrinous slough that required sharp surgical debridement, or concave wounds with soft tissue defects that met the criteria for NPWT were assessed for suitability for treatment with the HM.

The HM is a 3-layered system that includes the following: first layer, hydrogel; second layer, paraffin tulle dressing; and third layer, NPWT. A step-by-step illustration is shown in Figure 1. In order to standardize the NPWT element of the HM, the authors used an established commercially available NPWT for the subsequent cases presented in this case series. 

Once WBP was complete, patients were listed for a split-thickness skin graft (STSG) procedure, or the wound allowed to contract and heal by secondary intention. The UKMMC uses Duoderm Hydroactive Sterile Gel hydrogel (Convatec, Greenboros, NC), BACTIGRAS paraffin gauze (Smith & Nephew, Hull, UK), and the RENASYS NPWT device (Smith & Nephew, Hull, UK).

Each cycle for wound treatment is 4 ± 1 days. The total number of NPWT cycles for each patient is determined by serial wound inspection (WI) throughout the WBP stage, with close monitoring and assessment at each WI.  

Many patients have been treated with the HM since its initiation in the first quarter of 2014. In this case series, the authors report 8 different patients who were treated with the HM for a variety of wound types.

Case 1
A 32-year-old man was involved in a road  traffic accident in which he was riding a motorbike and collided with a car (Figure 2). He sustained a right open midshaft femur fracture with a right open proximal tibia fracture with patellar tendon avulsion (Schatzker type VI). He was initially treated in a different hospital, and had initial wound debridement with a spanning external fixation applied before transferring to the authors’ institution. 

The tibia-based wound measured 5 cm x 3 cm and had purulent discharge, which grew Pseudomonas spp and Staphylococcus aureus. No slough was evident but some granulation tissue could be seen over the wound. Due to the presence of infection, immediate open reduction internal fixation of the tibia was not possible, and definitive external fixation was embarked upon as an end goal. The planned gastrocnemius flap was initially delayed by wound bed infection and, ultimately, the patient did not consent to it.

The HM was initiated for this patient and changed every 4-5 days. He was also started on antibiotics concurrently. His wound closed after applying the HM for 6 cycles, approximately 25 days. (One cycle equates to the HM application until it is changed at the next WI.)  

Case 2
A 76-year-old male with underlying diabetes mellitus and hypertension presented with a right gluteal swelling inflamed with purulent discharge and had associated fever (Figure 3). The swelling was diagnosed as a carbuncle, and saucerization of the wound had been performed, leaving a 10 cm x 10 cm crater wound. On initial inspection, there was still slough seen at the wound site and the wound bed was not ready for STSG to cover the wound. 

The HM was initiated, and a notable decrease in the concavity of the wound could be seen after the technique was applied.  After 5 cycles of treatment with the HM, the wound had decreased to 6 cm x 6 cm with healthy granulation and was ready for STSG coverage.

Case 3
A 53-year-old man with underlying diabetes mellitus type 2 and hypertension presented with left foot necrotizing fascitis, affecting the tendons and ankle joint (Figure 4). After debridement and application of an external fixator for the left foot, the patient was referred to the plastics team for wound management and closure. Initial assessment showed necrotic patches over the foot with exposed tendons and lateral malleolus. After 7 cycles of HM, the necrotic tissue was debrided without instrumentation, and granulation tissue comfortably covered the exposed bone and tendons. The wound was then ready for STSG which was performed and the end result is shown. 

Case 4
A 69-year-old man presented with swelling of the left hand he had for 5 years that was subsequently diagnosed as basal cell carcinoma (Figure 5). Excision of the tumor included excision of tendons along with a segment of the first metacarpal bone. The tendons were reconstructed and internal fixation wires were placed. Following resection of the tumor, the wound bed comprised an exposed radial artery, reconstructed tendons, and internal fixation wires. The patient was immediately started on the HM following histopathological clearance of the tumor. After 6 cycles of the treatment over a 3-week period, the structures were covered by healthy granulation tissue and STSG was performed.  

Case 5
A 69-year-old woman with underlying diabetes mellitus type 2 with peripheral neuropathy, hypertension, valvular heart disease, and a history of breast cancer, presented with an infected wound of the right leg secondary to a 1% partial-thickness burn (Figure 6). She had applied a hot water bottle overnight to ease soreness in her legs, and replaced the hot water 3 times. Due to her neuropathy, she did not notice the noxious stimulus, and the burn was detected by her daughter who noticed it the next morning. Due to her comorbidities and poorly controlled diabetes, she refused formal surgical debridement, requesting conservative measures. She was started on the HM for 6 cycles over 24 days. Prior to discharge, the infection had resolved and the wound had contracted in size. 

Case 6
A 20-year-old man was involved in a motor vehicle accident resulting in comminuted fracture of the right acetabulum and left superior and inferior pubic ramus fracture (Figure 7). The patient had developed an infected Moralle-Lavalle lesion of the right hip/gluteus, and the wound was debrided. He was referred to the plastics team to manage the deep cavities in the upper and lower portions of his wound, then was started on HM, and the cavities closed after 7 cycles. The wound bed was then ready for STSG. 

Case 7
A 16-year-old girl sustained a crush injury of the left lower limb following a motor vehicle accident (Figure 8). She was treated for acute limb ischemia with underlying displaced fracture of the proximal third of the left fibula and left lateral malleolus. She underwent fasciotomy for compartment syndrome and subsequent debridement. Due to previously noted nonopacification of the anterior tibial artery with poor wound healing and dusky muscle, the patient was referred to the authors’ medical center for a second opinion. The patient underwent revascularization and was started on treatment with the HM. The initial wound had a deep, large cavity proximally, which is shown in Figure 8A. After 2 cycles of the HM, the cavity had approximated and was ready for STSG. The dimensions of the wound had also reduced in size, requiring a smaller graft area. 

Case 8
A 35-year-old man with underlying diabetes mellitus type 1 and hypertension presented with pain and purulent discharge from the left leg (Figure 9). It was diagnosed as necrotizing fasciitis, and the wound was debrided. Post debridement, there were exposed bones, and he was referred the authors’ medical center for wound coverage. The HM was initiated for 4 cycles. Prior to STSG, tendon and bone were covered with healthy granulation tissue with the cavities approximated. 

While no component of the HM is new, the combination of the 3 dressings are used as a novel technique in preparing the wound bed for definitive wound closure. This form of therapy is thought to work primarily via macrodeformation, microdeformation, fluid removal, and alteration of the wound environment.¹ It also produces secondary effects such as removing infiltrating leucocytes while simultaneously inducing inflammation, which encourages angiogenesis and stimulates peripheral nerve response.¹

The first layer involved in this technique is hydrogel, the second is a paraffin gauze dressing, and the third is NPWT. Each layer has a specific indication and helps prepare the wound bed for secondary healing or for the STSG (Table 1). 

The combination of dressings used in the HM were chosen to help facilitate debridement while simultaneously reducing the bacterial load and size of the wound. Hydrogel is primarily used in debridement³ by keeping the wound relatively moist, but not overly wet so as to cause maceration. Hydrogel functions by encouraging autolysis of necrotic tissue by water absorption.⁴ The paraffin tulle is placed to keep the hydrogel in place and help avoid suctioning it out when attached to the wall suction. Theoretically, the HM prepares the wound bed without requiring any mechanical debridement. Negative pressure wound therapy is also important in reducing overall exudate, which may delay the healing process.⁵

Joseph et al⁶ had previously described a decrease in wound volume over 6 weeks by 78% on NPWT compared to 30% on moist saline gauze (P = 0.038). However, there was no significant difference in time of healing. Negative pressure wound therapy is important in wound bed preparation especially in cases of noted skin loss, as reduction in wound size may require tissue or skin closure.

In reporting on this new technique, the authors present 8 patients who had sustained wounds due to trauma or tumor. All patients were at various stages of debridement when referred to the Wound Care Team. The challenges in each case were similar: reduce the size of the wound, obliterate cavities, eradicate infection, and cover exposed bones, tendons, or vessels with healthy granulation tissue. The hydrogel layer moisturizes the wound bed with excellent wound surface contact due to its conformability and provides an element of autolytic debridement; the paraffin tulle layer secures the hydrogel in place while providing wound permeability; the NPWT acts on macroscopic and microscopic levels. The aim was to achieve this while respecting patients’ wishes for conservative measures and working around lack of available time in the operating room. Once a healthy planar wound bed was achieved, the wound was either allowed to contract and epithelialize or had an STSG procedure performed.  

Limitations of this case series include the lack of a control arm, and that the results are purely anecdotal. Future studies should include a randomized, controlled trial for comparison and cost-benefit analysis. In this case series, the method produced favorable outcomes each time. It could be said that in future studies with a larger randomized, controlled trial cohort, there may be cases in which this treatment option fails.

As the HM is a new technique, there are no prior comparisons. The brief literature review is based on single wound therapies that make up the HM. All techniques have proved useful for different types of wounds, and the combination of these 3 modalities may be used for a wider range of wounds without having to perform multiple mechanical debridements. This new design method is viable and is helpful in both wound healing and wound closure. However, further clinical trials comparing the HM with NWPT or hydrogel dressings alone has to be performed to measure clinical outcome and cost effectiveness. 

Affiliations: Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia; and Cappagh National Orthopaedic Hospital, Finglas, Dublin, Ireland

Correspondence:
Farrah-Hani Imran, MB BCh BAO, MRCS, MS
Head of Plastic, Reconstructive Surgery, Burns & Wound Teams,
Department of Surgery, Faculty of Medicine,
Universiti Kebangsaan Malaysia Medical Centre 
(National University of Malaysia)
Jalan Yaakob Latiff
56000, Kuala Lumpur, Malaysia
farrahhani@gmail.com

Disclosure: The authors disclose no financial or other conflicts of interest.