Initial Experience Using Negative Pressure Wound Therapy With Instillation and Dwell Time for Postoperative Wound Treatment After Spinal Fusion Surgery: A Case Report

V.A.C. VERAFLO Therapy (3M + KCI) combines negative pressure wound therapy (NPWT) with instillation of a topical wound solution, such as normal saline solution, betaine/polyhexanide solution, and hypochlorous acid (HOCl), that dwells in the wound for a preprogrammed period of time, which is known as NPWT with instillation and dwell time (NPWTi-d).^1-3 This treatment has been shown to more effectively remove fibrinous and bacterial exudate than NPWT without instillation and also increases granulation tissue.^1,2

One of the treatment options with NPWTi-d is a reticulated open cell foam dressing with through holes (ROCF-CC; V.A.C. VERAFLO CLEANSE CHOICE Dressing; 3M + KCI); this was the dressing of choice in this specific case.^1,2 Wound lavage is facilitated by the removal of thick wound exudate and nonviable tissue.^1-3 Wound lavage was the treatment of choice in this specific case.

A retrospective study by Téot et al⁴ showed the use of NPWTi-d with an ROCF-CC dressing in 21 patients with large, complex chronic wounds. The authors measured the surface area of black nonviable tissue, the quantity of fibrinous slough, and granulation tissue formation. Early evidence suggests that the use of NPWTi-d with an ROCF-CC may help clean large, complex wounds when complete surgical debridement is not possible or appropriate and/or when areas of slough and nonviable tissue remain present on the wound surface.

A 73-year-old female with a history of hypothyroidism and arterial hypertension presented with lower back pain that extended into the back side of the left calf all the way to the heel of the foot. She was diagnosed with spondylolisthesis (level L4–L5) with stenosis of the spinal canal and treated with fusion and decompression (TLIF L4–L5) through a standard posterior approach to the lumbar spine. Postoperative treatment included standard analgetic and prophylactic antibiotic therapy. For postoperative wound dressings, a standard saline gauze dressing was used.

During the patient's hospital stay, wound care was supervised by a team of orthopedic and plastic surgeons. On postoperative day (PD) 5, bloody exudate from the surgical wound was observed. Gauze dressing changes (saline gauze dressing) were performed daily, and NPWT with continuous negative pressure was initiated with no decrease in exudate, which had become dark and odorous. Two weeks after admission (PD 13), the patient underwent revision surgery. During revision, the hematoma was removed and tissue samples for microbiological analysis were taken; samples were negative/remained sterile. Postoperatively, a prophylactic dose of vancomycin for 8 days was added to therapy. The wound was treated with NPWT (with continuous negative pressure) and daily saline gauze dressing changes.

Nine days after the second surgery, the exudate increased and NPWT was discontinued (4 weeks post admission). Five days later, a 2-cm dehiscence located at the superior end (12 o'clock) of the surgical wound and bloody exudate were observed. Necrectomy, debridement, and lavage of the wound were performed. The wound was treated with regular dressing changes (honey dressing, every 2–3 days), which also included medical-grade honey.

Wound exudate did not decrease. Additionally, the patient presented with pain in the lower limbs. Magnetic resonance imaging of the lumbar spine showed that a small amount of liquid had collected above the L4 spinous processes on the border between subcutaneous fat and the paravertebral muscle. Two months after admission, the patient again underwent revision surgery. During revision, an opening of the dura, measuring 1 mm x 1 mm, was successfully closed. Tissue samples were taken, and the results of microbiological analysis were negative.

The wound continued to heal very poorly. Eleven days after the third surgery, a dehiscence (3 cm x 2 cm) occurred in the middle of the wound that extended through the cutaneous and subcutaneous tissue and was covered with a layer of fibrous tissue. Necrotic tissue was visible between individual skin sutures, but with no signs of inflammation.

Dressing changes (honey dressing) were performed every day. Two weeks after the third surgery, NPWT with continuous negative pressure was resumed to improve wound healing.

Due to inadequate wound healing and failure of previous operative debridement procedures, a plastic surgeon was consulted. Considering the presence of necrotic tissue, necrectomy with subcutaneous suture removal was performed. At this point, NPWTi-d was recommended. Closing the lumbar fascia facilitated protection of the instrumentation from inadvertent bacterial invasion, allowing the authors to focus on prolonged local wound treatment. Keeping the wound open throughout dressings was mandatory to prevent premature closure of the skin with subsequent subcutaneous dead space formation, which would be detrimental to the desired clinical outcome.

Thus, 2 months after admission, NPWTi-d was initiated with -125 mm Hg of continuous negative pressure, saline solution, dwell time of 15 minutes, and an average instillation time of every 4 hours as well as utilizing the ROCF-CC dressing. During the 31-day treatment, 10 dressing changes were performed 3 to 5 days apart. Clinicians were careful not to expose the hardware within the wound bed. Individual sutures were used to close the lumbar fascia and the underlying paravertebral muscles over the hardware. During each dressing change, the hardware and wound were thoroughly examined. Because no hardware or wound infection was observed, saline solution was the solution of choice. The NPWTi-d treatment schedule, instillation settings, and wound measurements are listed in Table 1.

Before initiating NPWTi-d, wound dehiscence measured 5 cm x 3 cm and was spreading down to the muscular fascia (Figure 1). After the first 2 dressing changes, the size of the dehiscence decreased to 4 cm x 3 cm, and granulation tissue was visible at the bottom of the wound (Figure 2, Figure 3). After every dressing change, the dehiscence appeared smaller, the edges were more vital, and the amount of secretion was decreasing (Figure 4, Figure 5, Figure 6, Figure 7, Figure 8). On day 28 of NPWTi-d, wound dehiscence measured 2 cm x 1.5 cm (Figure 9B). The dehiscence presented with vital edges, minimal secretion, and granulation at the bottom of the wound (Figure 9A). At the conclusion of NPWTi-d therapy (day 31 of NPWTi-d treatment) a plastic surgeon was consulted. The surgeon recommended a wound treatment that included a combination of regular dressing changes, and traditional NPWT with continous negative pressure. The treatment duration with NPWT was 2 weeks. Use of a skin graft for wound closure also was discussed, but because the wound was healing and the patient had already undergone numerous revision surgeries, the authors decided against this form of treatment.

Four months after admission, the patient was discharged. Upon discharge, a small area of wound dehiscence remained that extended into the subcutis granulation tissue. No wound exudate was noted. At home, dressing changes (honey dressings) were performed every 2 to 3 days. The patient also had weekly follow-up visits in the orthopedic clinic until full wound closure occurred. Complete closure of the wound was achieved 1 month after the patient was discharged from the hospital.

Negative pressure wound therapy with instillation and dwell time has been shown to improve complex wound healing by eliminating necrotic tissue and rapidly generating granulation tissue, thus shortening healing time.^1,2 In a single-blinded study, Saaiq et al⁵ compared the use of NPWTi-d with standard wound care methods in 100 acute traumatic wounds. The authors reported benefits of using NPWTi-d with better and faster wound healing and shorter hospital stay compared with normal saline gauze dressings.

In 2013, Sinha et al⁶ compared the effects of NPWTi-d with standard wound therapy among 30 patients with open musculoskeletal injuries on the upper and lower limbs. Wound soft tissue defects decreased more than 5 mm (and as much as 25 mm) after NPWTi-d, compared with less than 5 mm using standard wound therapy (debridement, followed by daily cleansing with hydrogen peroxide and normal saline, and dressing the wound with povidone iodine [5%] and saline-soaked gauze).

Due to the complexity of the presented case and because no other treatment option had positive results, the authors initiated NPWTi-d. The authors also chose to use the ROCF-CC dressing with NPWTi-d. Several studies of the ROCF-CC dressing described its benefits in wound cleansing of thick exudate (fibrin, slough, and thick wet exudate) and other infectious material.^1,2,4-6 A case series of 5 patients with a pressure wound by Fernandez et al⁷ showed improved removal of devitalized tissue and subsequent granulation tissue formation. Wound therapy included NPWTi-d and an ROCF-CC dressing. Average treatment duration was 6 days. Additionally, the ROCF-CC dressing has been shown to help stimulate the generation of granulation tissue once necrotic tissue is removed.

With regard to instilled solutions, Hiebert and Robson⁸ reported that the use of HOCl reduced bacterial growth more efficiently than saline solution. In a prospective randomized study, Kim et al³ compared the effectiveness of normal 0.9% saline solution to antiseptic solutions (0.1% polyhexanide plus 0.1% betaine) for NPWT with instillation for the treatment of infected wounds. The authors suggested that saline solution may be as effective as an antiseptic solution for NPWT with instillation.

This was the authors' first experience with NPWT combined with instillation therapy. The repeated failure of other wound healing options provided the opportunity to try NPWTi-d. After treatment began, the authors observed decreased exudate, the beginning of granulation tissue formation, and a decreased area of dehiscence. The authors believe the initiation of NPWTi-d was a vital component to successful wound closure. Given the limitations of a single case study, larger studies need to be conducted to further validate the use of this therapy.

Authors: Samo Hrašovec, MD; and Gregor Rečnik, MD, PhD

Affiliation: Department of Orthopaedic Surgery, University Medical Center Maribor, Maribor, Slovenia

Correspondence: Samo Hrašovec, MD, Department of Orthopaedic Surgery, University Medical Center Maribor, Ljubljanska ulica 5, Maribor, Slovenia 2000 Slovenia; samo.hrasovec@gmail.com

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