Biodegradable bone plates and bonding systems
Inventors
McCarthy, Stephen • Weinzweig, Jeffrey
Assignees
NOVAPLAST Corp • University of Massachusetts Lowell
Publication Number
US-8870871-B2
Publication Date
2014-10-28
Expiration Date
2027-04-13
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Abstract
The invention relates to novel internal fixation devices, such as bone plates, generally and novel craniomaxillofacial bone plates more specifically and systems for bonding the same. More specifically, the invention relates to bone plates made of a polymer blend of (poly)lactic acid and Ecoflex as well as a novel hot-melt adhesive polymer blend of the same material.
Core Innovation
The invention provides novel internal fixation devices, specifically bone plates and craniomaxillofacial bone plates, constructed from a polymer blend that includes polylactic acid (PLA) and Ecoflex, and a system for bonding these devices to bone. The internal fixation devices are biodegradable and bioabsorbable, and are designed to address challenges with current fixation devices that require mechanical fasteners such as screws and power equipment for drilling, which increase surgical time and complication risk.
A hot-melt adhesive system is also disclosed, comprising a polymer blend of PLA and a biodegradable polyester such as Ecoflex, used to bond the bone plates to bone segments without the need for screws or drilling. The polymer blend used for both plates and adhesives allows for effective stabilization and fixation, while being resorbable and providing controllable plate porosity. The plates can be designed to be porous, allowing for impregnation with biologically active molecules, enhancing bone healing and enabling earlier resorption of the device compared to existing systems.
The invention addresses the need for an internal fixation system that simplifies craniofacial reconstructive surgery, eliminates the need for power equipment and mechanical fasteners, and allows for controlled biodegradation and delivery of bioactive agents. It also proposes a method for bonding bone segments or tissue using the hot-melt adhesive blend, which can be applied directly and set using heat, thus further simplifying surgical procedures by obviating mechanical devices.
Claims Coverage
There are two independent claims, each providing core inventive features related to methods for securing bone or bonding tissue using a bioabsorbable polymer adhesive blend.
Securing bone segments with a bioabsorbable flowable polymer adhesive
The method involves: - Applying a bioabsorbable, flowable polymer adhesive to a craniofacial bone segment, where the polymer blend includes polylactic acid and a polyester or a copolymer of polylactic acid and polyester, with polylactic acid content from about 10% to 80%. - Heating at least a portion of the polymer during application. - Contacting a second bone segment to the first segment. - Subjecting the segments to a compressive force until the polymer hardens. This inventive feature allows the fixation of bone segments without mechanical devices.
Bonding tissue by melting and applying a bioabsorbable polymer adhesive
The method includes: - Melting a bioabsorbable polymer adhesive blended with polylactic acid (10%–80%) and a polyester, or copolymer thereof, by heating at least a portion of the polymer. - Applying the melted polymer onto at least one bone tissue segment associated with craniofacial bone so that the polymer contacts the tissue. - Affixing this segment to another portion of bone tissue without using a mechanical fixation device. This method creates secure fixation or bonding of bone/tissue using a heat-applied bioabsorbable adhesive blend, eliminating the need for screws, plates, pins, or drilling.
The inventive features center on using a specific bioabsorbable polymer adhesive blend containing polylactic acid and biodegradable polyester for securing bone or bonding tissue in craniofacial applications, with application involving heating and direct fixation, thereby dispensing with traditional mechanical fixation devices.
Stated Advantages
Eliminates the need for screws and power equipment, thereby reducing surgical time, cost, and complexity.
Simplifies and expedites the intra-operative application of bone plates and fixation devices.
Permits earlier and controllable resorption of bone plates—within 3–6 months—compared to existing resorbable plating systems.
Allows for the impregnation of biologically-active molecules by creating porous, bioactive plate structures, supporting enhanced bone healing.
Provides improved mechanical properties in the bone plate, such as increased toughness and elongation to break, compared to pure PLA plates.
Reduces the need to remove plates post-operatively, especially in pediatric and special patient populations, by being fully resorbable.
Documented Applications
Craniomaxillofacial surgery for fixation and stabilization of bone segments during reconstructive procedures.
Stabilization and treatment of hand fractures and plates used in conjunction with osteotomies.
Direct bonding for certain hand and craniofacial fractures where bone plates may be contraindicated or mechanical fixation is not feasible.
Plate-less bonding for non-displaced or minimally displaced fractures, severely comminuted fractures, or in pediatric and elderly patients where mechanical fixation is impractical.
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