Massive necrotizing fasciitis following bellow-knee arterial surgery – A therapeutic challenge

Introduction. Necrotizing fasciitis is a rare, progressive bacterial infection of superficial fascia followed by secondary subcutaneous tissue necrosis. We pressented a patient with massive fulminant lifethreatening necrotising fasciitis after bellow-knee femoro-popliteal vein bypass grafting successfully treated by antibiotics, surgical debridement and final skin reconstruction using the Tierch method. Case report. A 61-year-old patient was admitted to the Vascular Surgery Clinic for below-knee femoropopliteal bypass grafting. He complained of intermittent claudication in the left leg after 50 m, ankle brachial indexes were 0.45 on the left and 1.0 on the right side. Femoropopliteal below-knee bypass grafting was done using the autologous great saphenous vein. In the very next day, initial signs of skin infection appeared including local inflammation, erythema, swelling and cellulitis restricted to saphenectomy site. These changes had rapidly spread in the following days on the deep tissue of the whole upper and lower leg, including the groin and with clinical signs of lifethreatening systemic infection. Immediate surgical debridement was done followed by extensive wound packing and wide spectrum antibiotics administration for the next 33 days when final skin reconstruction by the Tierch method was performed. Interesting point is that this entire time wound swab was sterile. Conclusion. In the presented case immediate surgical debridement, wide spectrum antibiotics administration and consistent wound packing gave satisfactory results in this life-threatening systemic infection. Wound swab is not always a reliable indicator of the infection while clinical findings and surgeons’ experience are of great significance in rapid reaction to this rare surgical complication.


Introduction
2][3][4][5][6][7] .The infective process leads to thrombosis of subcutaneous blood vessels, resulting in gangrene of the overlying skin.We presented a patient with massive fulminant life-threatening NF after bellow-knee femoropopliteal vein bypass grafting successfully treated by antibiotic, surgical debridement and final reconstruction by skin transplant using the Tierch method.The Institutional Ethics Committee approved the manuscript.

Case report
A 61-year-old male patient was admitted to the Vascular Surgery Clinic for below-knee femoro-popliteal bypass grafting.He complained of intermittent claudication in the left leg after 50 m of walking.The ankle-brachial index (ABI) was 0.45 on the left and 1.0 on the right side.Previously, multislice computed tomography (MSCT) (a General Electrics light speed VCT 64) discovered left superficial femoral artery occlusion as well as popliteal artery above knee with a good runoff of the crural arteries.As it was, below-knee bypass was indicated.The preoperative medical history of the patient included hypertension and hyperlipoproteinemia.All laboratory findings were within referent values [white blood cells (WBC) 5.1  10 9 /L (normal range 4.5-10.0 10 9 /L); haemoglobin (Hgb) -9.8 g/dL (normal range 13.5-17.5g/dL); platelets count 405  10 9 /L) (normal range 150-400  10 9 /L)].
The femoro-popliteal below-knee bypass procedure was performed using an autologous great saphenous vein graft from the left leg.Ceftriaxone 2 g/intravenous (iv)/24 h was administrated initially as usual postoperative antibiotic.Immediately after the surgical reconstruction, ABIs for the left foot were 0.82 and 0.77.
In the very next day, initial signs of skin infection were noted with accompanied local inflammation, erythema, swelling and cellulitis restricted to the saphenectomy site.
In the meantime, body temperature rase over 39 ºC and local necrosis rapidly progressed with associated ecchymosis, vesicles and bullae all around the incision sites.As soon as possible, more aggressive antibiotic therapy was introduced with ceftazidime (1 g/iv/12 h) and clindamycin (400 mg/iv/8 h), with concomitant iv crystalloid infusions.Still, the patient had a high fever followed by general malaise and unclear confusion.
Regardless a newly introduced therapy, as time went by skin lesions became deeper, accompanied by microvascular thrombosis and large surrounding areas of necrosis including the groin and calf.Superficial fascia was patchy with yellowishgreen colour followed by diffuse superficial muscle necrosis (Figures 1a and 1b).The first wound swab was sterile.At the moment, there was no imbalance concerning electrolytes, renal function, and glucose values.Blood and urine culture samples were tested, as well.
On the second day, extensive necrotic tissue excision and debridement removing the smelling parts of necrotic fas-cia and muscles were performed.Open wounds quoted bandage three to four times a day.All wound swabs taken daily were sterile.The whole leg was swollen, painful to touch, with limited mobility.

Fig. 1 -A) Massive necrosis of the left groin; B) thig and lower leg after femoro-popliteal bypass application.
The next few days, despite daily debridement, adequate wound toilets and vigorous antibiotic therapy, the patient was still highly febrile (38.2-40.2ºC)and extremely prostrated.The laboratory value of C-reactive protein was 150 mg/L (normal range < 10 mg/L), procalcitonin level > 0.25 ng/mL (normal level < 0.1 ng/mL), WBC 40  10 9 /L, erythrocyte sedimentation rate > 100 mm/h.The immune status was examined in detail, and we were not endorsed more important immunity disorders.
The plain x-ray films of the left leg revealed no gas in the involved tissues, thus the third time, we changed antibiotic therapy, introducing the most powerful combination with vancomycin (10 mcg/mL) and imipenem (500 mg/iv/6 h).Sixteen days later the body temperature dropped down on subfebrile level (37.5 ºC).Computed tomography (CT) did not identify pus collections or gas in the examined leg muscles.Several tissue biopsies and smear cultures did not isolate causative bacteria clearly.Also, pathogenic bacteria were not isolated from blood or urine.
After 33 days of extensive wound packing and antibiotic therapy, the local wound status was significantly better (Figure 2).Inflammation factors had a significant tendency to fall.When the wound looked clean enough with pearly grey looking fascia, without new signs of necrosis, skin transplantation was performed using the Tierch method with skin transplant taken from the other thigh (Figure 3).The skin transplant was well received, with no signs of rejection, nor reinfection.In the later stages of the treatment, the patient went to the everyday treatment in a hyperbaric chamber.

Fig. 3 -Local status after skin transplantaton (Tierch method).
The patient was dismissed from the hospital on the postoperative day 45 in good general condition with locally well healed and cicatrized wounds (Figures 4a and 4b).After a 6-month follow-up, local status of wounds was satisfactory (Figure 5).Although control CT angiography showed femoro-popliteal bypass occlusion, conservative treatment was indicated since the patient had claudication after 200 m and no signs of threating vascular ischemia were noted.

Fig. 4 -A) left groin; B) thigh and lower leg after 45
days.

Fig. 5 -Left leg local status after six months.
On the other side, a form of the group A streptococcal invasive disease (GAS) could be NF.Sometimes, the culture of tissue involved by NF also yields a mixture of other nonanaerobic bacterial agents such as Pseudomonas, Esherichia coli, Klebsiella, Clostridium and Staphylococci.The underlying conditions or diseases of NF are certainly some kind of an immunological failure mostly provoked by diabetes mellitus, malignant disease, renal failure, malnutrition, radiotherapy, hepatic disease, chronic skin ulcers and others.
The nature of infection involves a rapid progression of tissue necrosis.Possible causes are unknown aerobic or anaerobic bacteria and the expected clinical course is individual.This paper illustrates the evolution of rapidly spreading massive NF following below-knee femoro-popliteal autologous vein graft bypass.We believe that the condition associated with NF was probably operative trauma.Early recognition of the problem, persistent wound debridement and intensive antibiotic therapy prevented possible loss of the limb and other severe life-threating postoperative complications such as respiratory failure and sepsis due to released toxins into the bloodstream.
When discussing NF, in addition to surgical debridement and antibiotic therapy hyperbaric oxygen therapy (HBOT) and vacuum-assisted closure (VAC) system might be very helpful [15][16][17][18] .Some authors 15 report that HBOT could significantly improve the effectiveness of necrotizing soft tissues infection healing by bactericidal and bacteriostatic effects and increasing oxygen supply up to the cellular level.In contrast to this, the authors 16 of a recently published review concluded that none of the patients with NF had benefit from HBOT.In the presented case, HBOT was introduced as soon as infection was verified, still its effect remained questionable having in mind aggressive antibiotic therapy and persistent surgical debridement.Likewise, the use of VAC system has been reported with favorable outcome in managing non-healing limb wounds in patients suffering from acute NF 17,18 .Unfortunately, at the time VAC system had not yet been introduced to our Clinic.When NF is identified, all of these mentioned treatment modalities should be applied to contribute to faster wound healing.As for the diagnosis, prompt investigation such as ultrasonography and CT might be very helpful in recognising the problem timely and start immediate surgical excision of all necrotic tissue until a full recovery of the wound [12][13][14] .

Conclusion
The presented case suggests that surgical debridement, wide spectrum antibiotics administration and consistent wound packing give satisfactory results in fulminant necrotizing fasciitis treatment.