EVALUATION OF RESORBABLE PLATES WITH ULTRASONIC WELDED PINS IN THE MANAGEMENT OF MIDFACE FRACTURES (CLINICAL, HISTOLOGICAL, AND BIOMECHANICAL STUDY)

Abstract

INTRODUCTION: The use of biodegradable screws has a number of limiting factors including poor mechanical stability, difficult handling properties, and time-consuming fixation. A new application system by welding a special configured resorbable pin through ultrasound may overcome the disadvantages of thread tapping. OBJECTIVES: Was to evaluate resorbable plates with ultrasonic welded pins in management of midface fracture. MATERIALS AND METHODS: Was conducted clinically on 20 midface fracture cases fixed with resorbable plates with ultrasonic welded pins, histologically on 4 healthy adult mongrel dogs, and biomechanically on 15 specimens tested for tension, bending, and torsion stiffness of this system. RESULTS: Clinically intraoperative handling showed 13% failure rate for the total number of pins placed for all cases, with stability failure in 10% of cases, and mean time needed for fixation of each plate was 10.6 minutes, however postoperative clinical results were normal with no significant complications. Radiographically; adequate bone healing with delayed resorption of pins was observed during follow-up phase which was continued till 12th week postoperatively. Histological study revealed woven bone growing in the defect area and development of new bone, osteocytes and osteoblasts seen on bone surface. Biomechanical study showed mean tensile stiffness 498.982 N/mm while mean bending stiffness was 1.176 N/mm and mean torsion stiffness was 0.342 N/mm. CONCLUSIONS: This retrospective study shows the general feasibility, sufficient mechanical stability, and efficient intraoperative handling of resorbable plates with ultrasonic welded pins in management of midface fractures