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RECONSTRUCTIVE Muscle versus Nonmuscle Flaps in the Reconstruction of Chronic Osteomyelitis Defects Christopher J. Salgado, Background: Surgical treatment of chronic osteomyelitis requires aggressive M.D. debridement followed by wound coverage and obliteration of dead space with Samir Mardini, M.D. vascularized tissue. Controversy remains as to the effectiveness of different tissue Amir A. Jamali, M.D. types in achieving these goals and in the eradication of disease. Juan Ortiz, M.D. Methods: Chronic osteomyelitis was induced in 26 goat tibias using Staphylo- Raoul Gonzales, D.V.M., coccus aureus as an infecting inoculum. In a single stage, debridement followed Ph.D. by reconstruction using either a muscle flap (n ϭ 13) or a fasciocutaneous flap Hung-Chi Chen, M.D. (n ϭ 13) was performed. Flap donor sites were closed primarily and antibiotics El Paso, Texas; Kaohsiung, Taiwan; were given for 5 days postoperatively. Daily clinical evaluation for 1 year was and Sacramento, Calif. performed and monthly radiographs were obtained for 9 months and 1 year after the reconstruction. Results: Twenty-five flaps survived completely, and one nonmuscle flap under- went partial flap loss following a period of venous congestion. There were no postoperative complications in the muscle flap group. Two goats (15 percent) in the nonmuscle group developed superficial wounds in the immediate post- operative period that resolved with conservative management. No limbs had recurrent osteomyelitis wounds at 1 year of clinical follow-up examination. Radiographic evidence of osteomyelitis was present in two goats (15 percent) in the muscle group and one goat (8 percent) in the nonmuscle group. There was no statistically significant difference in the incidence of recurrent osteomyelitis between the groups by clinical and radiographic assessment. Conclusions: The findings in this study demonstrate that vascularized tissue flaps in the form of muscle or nonmuscle flaps provide viable options for wound coverage of osteomyelitis defects following adequate surgical debridement. (Plast. Reconstr. Surg. 118: 1401, 2006.) he treatment of osteomyelitis, particularly flaps.1,2 Before the use of local or free muscle after trauma, continues to pose significant flaps, the options for resurfacing osteomyelitis Treconstructive challenges. Surgical treat- defects following debridement included mainly ment of chronic osteomyelitis requires aggres- primary closure (immediate or delayed) and sive debridement of involved bony structures skin grafting. Over the past three decades, re- and soft tissues followed by definitive reconstruc- construction of these defects using pedicled and tion using viable local, regional, or distant free muscle flaps has been performed exten- sively and has yielded excellent success rates in From the Plastic Surgery Section, Department of Surgery, and many published series.2–7 Nonmuscle flaps have Biological Research Service, Department of Clinical Investi- also been used for the treatment of osteomyelitis gations, William Beaumont Army Medical Center; Depart- defects and have been reported in limited num- ment of Plastic Surgery, E-Da Hospital/I-Shou University; bers and with inconsistent outcomes.8–10 These and Department of Orthopedic Surgery, University of Cali- fornia Davis Medical Center. clinical series demonstrating the effectiveness of Received for publication March 2, 2005; accepted June 2, muscle flaps and nonmuscle flaps in the treat- 2005. ment of osteomyelitis wounds have all lacked in Presented in part at the American Society for Reconstructive providing consistency in the extent and severity Microsurgery Annual Meeting, in Fajardo, Puerto Rico, of the bone infection and its correlation with January 15 through 18, 2005. recurrence of the osteomyelitis, which occurs in Copyright ©2006 by the American Society of Plastic Surgeons at least 15 percent of cases. The success of non- DOI: 10.1097/01.prs.0000239579.37760.92 muscle flaps in some published series has not www.PRSJournal.com 1401 Plastic and Reconstructive Surgery • November 2006 been totally convincing to many who believe that tion that it is as effective in treating the disease. muscle is necessary to provide bulk and superior Despite reports of clinical successes with skin blood supply and to aid in the healing of osteo- flaps for the treatment of chronic osteomyelitis myelitis defects. wounds, a controlled model is essential to clarify Longstanding surgical dogma, based on previ- the true relationship between osteomyelitis ous experimental studies and a large volume of wounds and vascularized tissue of various forms clinical evidence, has clearly demonstrated the (muscle versus nonmuscle). The lack of a con- effectiveness of muscle flaps in the treatment of trolled experimental study provided the motiva- osteomyelitis wounds. Although muscle flaps tion for this investigation. have been shown to be superior to nonmuscle flaps in bacterial growth inhibition and elimina- MATERIALS AND METHODS tion, early increased skin oxygen tension has Twenty-eight goats (Capra hircus) were used been found to be present to a larger degree in 11 for this study. The experimental design and pro- fasciocutaneous flaps. Nevertheless, there are tocol were approved by the Department of Clinical no controlled, randomized studies demonstrat- Investigation’s Institutional Animal Care and Use ing the superiority of muscle flaps over non- Committee at William Beaumont Army Medical muscle flaps in the eradication of osteomyelitis Center, and all experiments were conducted in following surgical debridement of infected the animal surgical laboratories of this institution. bone. If a comparative study were to be per- The goats were obtained from farm flocks and formed in a clinical model, a significant flaw were cared for in accordance with the Biological would be the inability to accurately quantify the Research Service’s Farm Animal Care Procedures. degree of osteomyelitis or amount of infected The animals were housed in the large-animal area bone, and therefore a true comparison would of the Biological Research Service and were al- not be possible. The type of organism, its viru- lowed free access to water. They were fed daily with lence, and its susceptibility to antibiotics are a ruminant laboratory diet (Rumilab 5508; Purina other variables that are uncontrollable in a clin- Mills, Brentwood, Mo.), and were supplemented ical model, thus making an accurate comparative with fresh alfalfa under the nutritional guidance study between muscle and nonmuscle flaps not of the attending veterinarian (R.G.) to provide achievable. The Cierney-Mader model has been standard nutritional support. All animals were used to clinically stage osteomyelitis. It identifies screened negative for brucellosis and Q-fever be- four major factors influencing the treatment and fore enrollment in the study. Two goats were la- prognosis of chronic osteomyelitis: (1) the de- beled as refinement goats and were used to ensure gree of necrosis, (2) the condition of the host, the success of the proposed muscle and non- (3) the site and extent of involvement, and (4) 12 muscle flap harvest techniques. The average age of the disabling effects of the disease itself. This the animals was 2 years (range, 1 to 4 years) and model does not take into consideration the type the average weight was 34 kg (range, 25 to 45 kg.). of organism in the wound or its concentration. In a previous study at this institution,13 an animal model for chronic osteomyelitis was developed Anesthesia Protocol in a goat tibia using a known concentration of For the radiographic procedures, xylazine (0.5 infecting inoculum. This model was then used mg/kg intramuscularly) was administered for im- for the purpose of this study; to evaluate the mobilization and yohimbine was used as a reversal effectiveness of muscle versus nonmuscle flaps in agent (0.11 mg/kg intramuscularly). For the sur- the eradication of chronic osteomyelitis after gical procedures, the goats were induced using a surgical debridement. combination of ketamine and diazepam. The Chronic osteomyelitis produces significant goats were then intubated and a cephalic intrave- deficits in the involved limb; therefore, the cur- nous catheter was placed. General endotracheal ative procedure should bear extreme consider- anesthesia was maintained using an inhalation ation to preservation of structures that provide agent (isoflurane) administered using an animal- function. Theoretically, if local and regional specific anesthetic system (Ohmeda Modulus an- flaps are considered for use, nonmuscle flaps esthesia system; Ohmeda, Madison, Wis.). All an- would offer the added advantage of preserving imals had a fentanyl patch, 25 g/hour, placed on muscle function by sparing the muscle and its the dorsum of their shaved necks approximately function at its potential donor site and would 12 hours before surgery and then changed at 72 provide a more ideal donor flap, on the condi- hours postoperatively. If excessive pain was noted 1402 Volume 118, Number 6 • Chronic Osteomyelitis Defects on clinical examination by the veterinarian, an- Before surgery, food and water were withheld other patch was placed in addition to the first. The for 24 hours. Preoperatively, the animals were fentanyl patch was discontinued after 1 week in shaved from the mid trunk distally. Surgical access both groups. to the left proximal tibial metaphysis marrow cav- ity was achieved through a 2.0-cm skin incision Creation of Osteomyelitis Model