Maggot Debridement Therapy in Necrotizing Fasciitis Reduces the Number of Surgical Debridements

Case Report

A 46-year-old man with no relevant medical history besides an appendectomy and a perianal fistula more than 20 years before current presentation was referred to the authors’ hospital with a Fournier's gangrene after he was first examined in the emergency department of the referring hospital. The patient had a history of smoking and consumed about 36–56 g of alcohol daily (3–4 units). The patient presented with a red and tender right scrotum, which in retrospect, had been present for 7 days. His general practitioner had treated him with oral Ciprofloxacin® over the preceding 4 days for a presumed infected sebaceous gland in the right groin. The patient was taken to the operating room after administration of broad-spectrum antibiotic therapy with netilmycin amoxicillin, and metronidazole. An extensive area of fasciitis was found predominantly on the right side of the abdomen, scrotum, and perineum. A large part of the abdominal skin (including abdominal fascia) and scrotum were excised (Figure 1). Initial gram-staining showed a mixed culture. Definitive cultures showed bacteroides, diphtheroids, and Enterococcus faecalis. Six surgical debridements were performed over the following 10 days.
It was decided to perform MDT because sepsis persisted and the wound did not show any signs of healing. An average of 20–30 sterile Lucilia sericata maggots were placed in each biobag (Vitapad®, Polymedics Bioproducts, B.V.B.A. Peer, Belgium) on the wound (Figure 2). The patient was treated with the maggots for 19 days. A total of 1,200 maggots were applied. The wound was well granulated after the maggot treatment (32 days after initial presentation to the authors’ hospital). The wound was partially closed secondarily and a mesh graft was used to close the rest of the wound. Postoperative course was uncomplicated following this last operation. The patient was discharged from the hospital, returned to work, and has remained in good condition for more than 3 years after the last operation (Figure 3).

Methods

Patients who presented to the authors’ hospital with necrotizing fasciitis were treated with a combination of surgical debridement, antibiotic therapy, and MDT. Patient and treatment characteristics were recorded from the patients’ charts. All MDT applications where discontinued when the wounds were 100% red and fully granulated. Discontinuation of the therapy was a clinical decision. Throughout this study, all maggot applications where performed using the contained technique (biobags). In the biobag technique, larvae are enclosed between 2 layers of 0.5-mm polyvinyl alcohol hydrosponge, which are heat-sealed, and then a small cube of spacer material is inserted to prevent bag collapse.¹⁰ The bag containing the maggots is placed inside the wound. A net is placed over the bag and taped to an adhesive on the wound edges. Wet gauze and a light bandage are wrapped over the net. Catheters are placed inside the bandages in order to wet the gauze 3 times daily with normal saline solution (0.9%)—this prevents maggot death from dehydration. Every 3 to 4 days new contained maggots were placed on the wound until thorough debridement was reached. The gauze was changed daily. Maggots derive nutrients through a process known as “extracorporeal digestion.” They secrete proteolytic enzymes that liquefy necrotic tissue. The enzymes move freely through the biobag.
Possible differences in patient and treatment characteristics and outcomes were statistically tested using SPSS™ version 12.0.1 for Windows® and then evaluated. For analysis, the patients were split into 2 groups according to the median number of days of starting MDT after diagnosis of the necrotizing fasciitis.

Results

From November 2001 to December 2005 a total of 15 patients with necrotizing fasciitis were treated in the authors’ hospital with a combination of surgical debridement, antibiotic therapy, and MDT (Table 1). After diagnosis, all patients received broad-spectrum antibiotic therapy, which was changed according to the antibiogram. All patients were treated with surgical debridement after a clinical diagnosis of necrotizing fasciitis. There were 10 men (67%) and 5 women (33%) treated (Table 2). Ages ranged from 18–79 years with an average age of 51 years. The necrotizing fasciitis was located in the groin area (n = 6; 40%), upper leg (n = 3; 20%), arm (n = 3; 20%), abdomen (n = 2; 13%), and head/neck region (n = 1; 7%). Three patients were diagnosed with Fournier’s gangrene (20%).
The patients needed an average of 2.9 debridements (range 1–6). In 5 of the 15 patients, Streptococcus pyogenes was the sole causative agent. Two patients (13%) died, 1 from cardiogenic shock, and the other due to metastasis of a primary urothelial cell carcinoma. Both deaths were not due to postponed surgical debridement. An average of 45 biobags per patient (range 9–100 bags) were needed. The MDT period was on average 17 days (range 3–38 days).
The patients were split into an “early treated” group (within 9 days after diagnosis; n = 8), and a “late treated” group (more than 9 days after diagnosis; n = 7), because the median number of days to MDT start after diagnosis was 9 days. This was done to gain insight at to the effect early application of maggots in necrotizing fasciitis might have on improving patient prognosis. There were no statistical significant differences in outcomes between the early- and late-treated groups; although, the early treated group had a shorter ICU stay (4 days versus 29 days; P = 0.213) and a shorter total hospital stay (30 days versus 59 days; P = 0.094). The number of surgical debridements was less and statistically significant in the patients where maggots were applied within 9 days after diagnosis (1.8 versus 4.1 surgical debridements;
P = 0.001). Excluding the 2 patients who died, the wounds eventually healed either by secondary intention or surgical closure in all of the patients. Secondary closure was performed on average after 10 days (range 0–21 days), and mesh graft at 19 days (range 0–39 days) after the end of MDT.

Discussion

Fifteen patients with necrotizing fasciitis are described in whom treatment consisted of surgical debridement and antibiotic therapy, as well as treatment with sterile maggots. This study showed that in most cases, this potentially lethal condition was successfully treated with this technique.
Necrotizing fasciitis can affect any part of the body but the extremities, the perineum, and the truncal areas are most commonly involved.¹¹ In this study, most patients (40%) had necrotizing fasciitis of the groin area. Mortality rates for necrotizing fasciitis reported in the literature range from 6%–76%; mortality rates are significantly increased if operative debridement is delayed.¹ Failure to recognize and diagnose necrotizing fasciitis possibly contributes to the high mortality rate.¹² Diagnosis of this disease remains a clinical one—severe pain disproportionate to local findings in association with systemic toxicity should raise suspicion.¹¹
More than 75 years ago, MDT was used in a clinical hospital setting for the treatment of osteomyelitis.¹³ More recently, MDT has proven to be a valuable treatment option for various indications. In 2000, Wollina et al¹⁴ described indications for MDT— fasciitis necroticans was not separately mentioned. Frequent indications reported in the literature are for treating leg ulcers and pressure sores.^15–20,27 Nigam et al²¹ recently published an article discussing evidence supporting the potent antibacterial action of maggot secretions. Aside from debridement and disinfection, a third important factor of MDT is discussed: enhanced healing.²¹ Although success rates for MDT reported in literature vary, 80% is the closest estimated percentage.²²
In-vitro and in-vivo investigations have shown that sterile maggots (larvae of Lucilia sericata) are especially capable in the treatment of infected wounds with gram-positive bacteria.⁹ Necrotizing fasciitis, which is mainly caused by gram-positive bacteria, seems to be an ideal indication for MDT.^6–9 Urgent, radical surgical debridement in combination with broad-spectrum antibiotic therapy is necessary after necrotizing fasciitis has been diagnosed.⁵ In the authors’ experience, repeated debridements are needed.
The only reports of necrotizing fasciitis treated with maggots have been seen in case reports. Two of the 15 herein reported patients have been reported earlier—1 patient with a Fournier’s gangrene²³ and 1 patient with necrotizing fasciitis after a pelvic fracture.²⁴ Successful debridement with MDT of fasciitis of the head and neck²⁵ and Fournier’s gangrene²⁶ have been described recently. The literature debates that MDT is contraindicated in cases of rapidly advancing infections, such as necrotizing fasciitis.^27,28 The authors disagree, although would stress that the first debridement in a case of necrotizing fasciitis should always be surgical. Only after administration of broad-spectrum antibiotic therapy and surgical debridement can maggots be placed on the wound as an additional treatment method, not as the sole treatment.
This patient series showed that relatively early application of maggots reduced the number of surgical debridements. In the early treated group the number of surgical debridements was considerably lower in comparison to the late treated group (1.8 versus 4.1;
P = 0.001). This means that the use of maggots reduced the necessity to go back to the operating room to perform surgical debridement. It is important that healthcare professionals and patients realize that MDT is not the only wound treatment available for necrotizing fasciitis. After adequate debridement and disinfection, other treatments are sometimes necessary before wound closure can be achieved. Vacuum assisted closure (V.A.C.® Therapy, KCI, San Antonio, Tex) is a potent wound therapy to stimulate further granulation tissue. In cases of necrotizing fasciitis, vacuum-assisted closure has proven its value.^24,29,30
A reduction in the number of surgical debridements could lower the mortality rates associated with necrotizing fasciitis. Furthermore, the cosmetic and functional outcome might be improved because the number of surgical procedures is reduced. This is because maggots are able to distinguish between viable- and nonviable tissue more effectively than a surgeon. Caution should be taken before definitively concluding that MDT replace surgical debridement altogether, which cannot be concluded from a retrospective case series.