Bone Tie Loop for Pars Fracture Stabilization
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Solution Overview
Problem
Current methods for treating pars fractures, such as activity modification and surgical fusion, often fail to effectively address persistent pain and instability in the spine, leading to complications like spondylolisthesis due to inadequate healing and misalignment of fracture ends.
Innovation Solution
A bone tie device and method for stabilizing and fusing pars fractures by drilling lumens in pedicles and laminae to secure a bone tie that forms a loop around the fracture, applying compression to unite fractured ends and promote healing, potentially using bioabsorbable materials for temporary support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw is placed through the pars to bridge the fracture, then the fracture is stabilized, but further complications and unsuccessful fusion occur where a large gap in the pars remains
Solution Approach 1:
The bone tie is divided into multiple segments: a first loop portion that wraps around the first pars interarticularis, a second loop portion that wraps around the second pars interarticularis, and a connecting portion that bridges between them. This segmentation allows each loop to independently compress its respective fracture site while the connecting portion maintains overall structural integrity, eliminating the large gap problem associated with single-screw fixation.
Solution Approach 2:
The invention transitions from linear screw fixation to a three-dimensional loop configuration. The bone tie forms loops around the pars interarticularis on both sides of the fracture, creating a circumferential compression mechanism that applies force from multiple directions rather than a single linear path, thereby improving fusion reliability.
2Object-affected harmful factors
If activity modification and bracing are used to allow rest and promote healing, then pain is temporarily reduced, but persistent pain and instability remain leading to spondylolisthesis
Solution Approach 1:
The bone tie acts as an intermediary device that provides mechanical stabilization between the fractured pars interarticularis segments. By forming loops around both the first and second pars interarticularis and connecting them, the bone tie mediates the transmission of compressive forces across the fracture site, enabling reliable healing that prevents spondylolisthesis and eliminates persistent pain.
3Ease of operation
If a screw is placed through the pars to bridge the fracture, then surgical intervention is provided, but the procedure leads to unsuccessful fusion where a large gap in the pars remains
Solution Approach 1:
The invention changes the fixation parameter from rigid linear screw insertion to flexible loop configuration. The bone tie's loops can adapt to the anatomical curvature of the pars interarticularis, and the tightening process allows progressive compression that pulls fracture ends into precise alignment, overcoming the alignment limitations of standard screw fixation.
Data Source
AI summary
Various embodiments of bone ties and methods for treating the spine are provided. The method can include forming a first lumen in a pedicle on a first side of a pars fracture. The method can include forming a second lumen in a lamina on a second side of the pars fracture. The method can include positioning a bone tie through the first lumen and the second lumen, the bone tie comprising a distal end and a fastener section. The method can include tightening the bone tie by passing the distal end of the bone tie through the fastener section of the bone tie.