RESUMO
BACKGROUND: Previous studies of pulsed magnetic fields have reported enhanced fracture and chronic wound healing, endothelial cell growth, and angiogenesis. This study characterizes the biomechanical changes that occur when standard cutaneous wounds are exposed to radiofrequency pulsed magnetic fields with specific dosage parameters, in an attempt to determine whether return to functional tensile strength could be accelerated in wound healing. METHODS: There were two study phases and a total of 100 rats. In phase 1, wounds were exposed to a 1.0-G pulsed magnetic field signal in clinical use for wound repair for 30 minutes twice daily for 21 or 60 days. Phase 2 was a prospective, placebo-controlled, double-blind trial in which rats were treated for 30 minutes twice daily with three different low-amplitude signals (0.02 to 0.05 G), configured assuming a Ca binding transduction pathway, for 21 days. A midline, 8-cm, linear skin incision was made on the rat dorsum. Tensile strength was determined by measuring the point of rupture of the wound on a standard tensiometer loaded at 0.45 mm/second. RESULTS: The mean tensile strength of treated groups in phase 1 was 48 percent (p < 0.001) greater than that of controls at 21 days; there was no significant difference at 60 days. In phase 2, the treated groups showed 18 percent (not significant), 44 percent, and 59 percent (p < 0.001) increases in tensile strength over controls at 21 days. CONCLUSION: The authors successfully demonstrated that exposing wounds to pulsed magnetic fields of very specific configurations accelerated early wound healing in this animal model, as evidenced by significantly increased wound tensile strength at 21 days after wounding.
Assuntos
Campos Eletromagnéticos , Pele/efeitos da radiação , Cicatrização/efeitos da radiação , Animais , Modelos Animais de Doenças , Masculino , Ratos , Ratos Sprague-Dawley , Pele/fisiopatologia , Resistência à TraçãoRESUMO
Palatal integrity is essential for useful speech, deglutition, good oral hygiene, and prevention of nasal regurgitation. Maxillary defects after tumor extirpation, therefore, can have serious functional and cosmetic implications. Given the often disappointing results obtained with local and regional pedicled flaps for maxillary reconstruction, a variety of microvascular free flaps have been utilized in recent years, including the rectus abdominis, fibular, radial forearm, and latissimus dorsi flaps. Experience with these techniques has been documented in a limited number of case reports. We describe our single-stage approach to maxillary and nasal floor reconstruction with the double skin-paddle rectus abdominis musculocutaneous free flap. A series of five patients is presented; six of these immediate free flap reconstructions were performed for defects resulting from tumor resection. A vertical rectus abdominis musculocutaneous free flap was used in all cases, designing two separate skin paddles to accommodate the measured maxillary and nasal floor deficiencies. Anastomoses of the deep inferior epigastric artery and vena comitans were performed end-to-end to the facial artery and vein, respectively. In addition, orbital floor reconstruction with calvarial bone grafts or titanium mesh was performed in all five patients. Separation of the oral and nasal cavities was maintained postoperatively. No intraoperative complications, perioperative mortalities, flap losses, instances of skin paddle necrosis, hematomas, or oronasal fistulae were observed. One patient required bedside drainage of a surgical site abscess that resolved without adverse sequelae. Over the past 4 years, the double skin-paddle rectus abdominis musculocutaneous free flap has provided reliable results at our institution for single-stage reconstruction of maxillary and nasal floor defects. This reconstructive technique should be considered a viable method that can alleviate the functional and cosmetic debility associated with these defects.