Muscle and musculocutaneous flaps have been used reliably in reconstruction of soft-tissue defects for many years. Previous experimental studies have shown musculocutaneous flaps to be superior to the random pattern and fasciocutaneous flaps in the management of infected wounds. Over the past decade, perforator flaps have gained acceptance as alternative methods of reconstruction in the clinical setting that can decrease donor-site morbidity and hospital stay, and increase patient satisfaction. The authors theorized that perforator flaps may be able to handle infected wounds better than random pattern and fasciocutaneous flaps because their blood supply is essentially the same as many of their musculocutaneous counterparts. The goal of this study was to compare the S1 perforator-based skin flap and latissimus dorsi musculocutaneous flap in the dorsal flank of the rabbit with the introduction of bacteria to simulate both superficial and deep wound infection. Measurements of oxygen tension and regional perfusion index were performed on both types of flaps to ascertain their viability and capacity to heal. The authors found no statistical significance between latissimus dorsi musculocutaneous and S1 perforator flaps in the rabbit with respect to superficial and deep wound infections. The regional perfusion index was calculated for postoperative days 1, 2, and 4. No statistically significant difference between the two flaps using the regional perfusion index could be identified. Additionally, regional perfusion for both types of flaps was greater than 0.6, indicating that their capacity to heal wounds is similar.

Sixteen patients with necrotizing fasciitis were observed under clinical and laboratory conditions for collection, preservation, and culture that permitted optimal retrieval of anaerobes. The clinical observations of necrosis of fascia, subcutaneous fat and skin with thrombosis of the microvasculature, and absence of myonecrosis were clearly apparent in these patients. Two clear-cut groups of culture and gram stain results were found, suggesting that the clinical entity of necrotizing fasciitis can occur after infection by different infecting organisms. The cultivation of Streptococcus pyogenes (group A), either alone or in combination with staphylococcus, in three patients conforms to the culture results found by Meleney [1] in his original description.

Regional nutrient blood flow to musculocutaneous and fasciocutaneous flaps was studied in dogs using 15-microns radiolabeled microspheres, and correlations to bacterial inoculation into closed wound spaces were sought. During the 6-day study period, no differences were found between blood flow to noinoculated versus inoculated flaps. Comparisons of blood flow to the deep surfaces of the flaps showed that blood flow to muscle in musculocutaneous flaps increased rapidly during the first 24 hours and then plateaued, while that to subcutaneous tissue plus fascia in fasciocutaneous flaps demonstrated a gradual and steady increase. The most rapid decline in bacterial counts at the undersurface of both flaps occurred within 24 hours, dropping significantly lower within musculocutaneous flaps. In addition to such surface properties of muscle as tissue ingrowth, rapid early augmentation of muscle blood flow may be largely responsible for superior bacterial suppression observed beneath musculocutaneous flaps.

Host-pathogen interactions were studied in tissue biopsy samples from patients with severe invasive group A streptococcus (GAS) infections. Skin, subcutaneous tissue, and fascia biopsy samples were divided into clinical grade 1 (no evidence of inflammation [n=7]) or clinical grade 2 (inflamed tissue--erythema and edema including cellulitis, fasciitis, and necrotizing fasciitis [n=24]). In situ imaging demonstrated significantly higher bacterial load in biopsy samples of higher clinical grade (P<.05), and the bacterial load correlated with the in vivo expression of the superantigen streptococcal pyrogenic exotoxin F (P<.02). Increased expression of the interleukin-1 cytokines and significantly higher expression of tumor necrosis factor-beta, interferon-gamma, and the homing receptors CC chemokine receptor 5, CD44, and cutaneous lymphocyte-associated antigen (P<.002-.05) were observed in biopsy samples of higher clinical grade. Thus, the cytokine profile at the local site of infection mimics that of a typical superantigen cytokine response. The findings of this study demonstrate a critical role for superantigens and Th1 cytokines in GAS tissue infections.

Necrotizing fascitis is a rare but rapidly progressive soft tissue infection not previously reported in an obstetric patient. Since cure is dependent on rapid recognition and early surgical intervention, 4 cases are reported herein, the bacteriology discussed, and the literature reviewed.

Human blood collected from two patients from Westchester County, New York with human granulocytic ehrlichia (HGE) infection was inoculated into two ponies. Inoculated ponies developed clinical signs similar to a previous report (Madigan et al., 1995). Histopathological changes involved follicular hyperplasia of lymphoid tissues. HGE DNA was detected by PCR in muscle, fascia, peritoneum, and adrenal gland after the ponies produced a high level of antibodies to HGE. We suggest that HGE may reside in poorly vascularized connective tissues, where the antibodies may have some difficulties to penetrate, resulting in persistent infection. Since HGE and E. equi cause very similar diseases in both humans and horses, they may be the same organism with minor genetic differences.

This study evaluated a PCR assay for detection of the streptococcal pyrogenic exotoxin B (speB) gene from tissue biopsy specimens of patients with necrotizing fasciitis. speB was detected in specimens from all 10 patients with necrotizing fasciitis due to group A streptococcus. The assay was negative for all 11 patients without culture or serologic evidence of streptococcal infection. These results suggest that the detection of speB by PCR may be useful for confirming group A streptococcal infection when cultures are negative or not available.

Banked irradiated fascia lata is used in many ophthalmic procedures. Along with its increased popularity has come concern over protection from the AIDS virus. Banked fascia lata is protected against the AIDS virus by donor selection, antibody testing and irradiation sterilization. With the knowledge that fascia may also be heated as additional protection, this study was performed to determine if heat treatment weakens the fascia. Results suggest that heat treatment does not clinically or statistically weaken banked homogenous fascia lata.

The clinical spectrum of disease caused by Cardiobacterium hominis, a small, gram-negative coccobacillus, is little known to physicians. From analysis of a new case of C hominis endocarditis on a fascia lata aortic valve, and from review of all previous reports of infection due to this microorganism, a remarkably consistent clinical picture emerged. C hominis only causes endocarditis, affects middle-aged individuals with structurally abnormal, left-sided cardiac valves, and follows a subacute course associated with the frequent occurrence of mycotic aneurysms and embolic phenomena. The methodology and therapeutic importance of identifying this organism and separating it from the closely related Actinobacillus actinomycetemcomitans, Eikenella corrodens, and Haemophilus aphrophilus is emphasized. Either penicillin alone or penicillin plus an aminoglycoside is recommended for therapy.

Infection of the musculoskeletal system encompasses a variety of conditions, affecting skin, fascia, muscle, joints, tendon sheaths, and bone. In addition to features unique to each tissue site, these processes vary with respect to organism virulence, overall host condition, and the condition of the extremity itself, particularly its circulation. Treatment of musculoskeletal infection varies according to these features, and with respect to the presence of devitalized tissue. Unfortunately, while clinical examination is accurate for the presence of infection as a process in most circumstances, it lacks specificity for the variety of disorders within the spectrum of extremity infection. MRI examination using intravenous contrast is becoming the preferred modality to study complicated extremity infections, since it provides an accurate portrayal of the extent of osseous and non osseous involvement, and identifies areas of necrosis. This information provides a basis from which clinicians may more accurately choose from among treatment options.