Analysis of Frontal and Orbital Osteotomy Fixation Using a Novel Adhesive Resorbable Plating System for Craniofacial Reconstruction
Jeffrey Weinzweig, MD1, Jeffrey Manchio, MD1, Sonu Jain, MD1, Shawkat Sati, MD1, Kip Panter, PhD2, Anshuman Shrivastava, PhD3, Stephen McCarthy, PhD3.
1Lahey Clinic, Burlington, MA, USA, 2USDA, Logan, UT, USA, 3University of Massachusetts, Lowell, MA, USA.
Background: The ideal system for fixation of the pediatric craniofacial skeleton would (1) provide adequate bony stabilization, (2) resorb rapidly (within 3-6 months) with minimal local tissue reaction, (3) be low profile, (4) have bioactive modules, and (5) be user-friendly without the need for drilling equipment. To date, no existing system currently fulfills any of these criteria other than the first. The purpose of this study is to introduce NovaPlast, a novel adhesive resorbable plating system for craniofacial reconstruction that is capable of fulfilling each of these criteria.
Methods: A novel biodegradable polymer blend consisting of an 80:20 combination of a polylactic acid-based polymer and a polyester co-polymer in a co-continuous phase was used to develop a 1.5 mm resorbable plating system, NovaPlast. This system demonstrates superior tensile and mechanical properties such as stiffness, toughness, and elongation to break, as well as excellent biodegradability and aging properties compared with polylactic acid (PLA) and other similar polymers used in existing plating systems (patent pending - JW/SM). A biodegradable polyester compound serves as an adhesive for this plating system, making drilling and the use of screws for fixation unnecessary. The PLA-polyester blend also provides stabilization of osteotomy segments as a stand-alone adhesive preparation, NovaBond, without the use of plates in selected applications (patent pending - JW/SM). A biodegradable polyester compound serves as an adhesive for this plating system.
Bilateral frontal bone osteotomies (3 cm x 1 cm) and orbital rim osteotomies (1.25 cm x 0.75 cm) were performed in nine groups of four 6-week-old goats. Bone graft fixation was performed by three resorbable methods: (1) NovaPlast plates + adhesive; (2) NovaBond adhesive alone; (3) Stryker Delta plates + screws (Control). Animals in each group were harvested 6 weeks, 3 months and 6 months post-operatively; specimens were evaluated histologically, biomechanically, and ultrastructurally by EM at these timepoints. Efficacy of operative time, bony fixation, and rapidity of polymer resorption of the novel NovaPlast and NovaBond systems were compared with the Delta system, which served as a control.
Results: Operative times were significantly reduced in the NovaPlast and NovaBond groups compared with the traditional Delta system. The Delta technique required 4x the amount of operative time required by the NovaBond technique and 2x that required by the NovaPlast technique.
Excellent fixation of bone grafts and solid bony healing were achieved in all groups at each of the time points as demonstrated biomechanically and histologically. NovaBond specimens demonstrated significantly greater breaking strength at the osteotomy sites compared with both Delta and NovaPlast specimens.
Conclusion: The NovaPlast adhesive resorbable plating system and the NovaBond resorbable adhesive are both effective in providing adequate bony fixation of the craniofacial skeleton and facilitating bony healing. Current studies are evaluating the efficacy of additional modules of this novel system including a 0.5 mm plate as well as a bioactive porous plate that will enable impregnation with nanospheres (NovaSpheres) containing BMP and other growth factors and molecular components.