Magnetic Cross-Connector Insertion System for Spinal Implants
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Solution Overview
Problem
Current spinal fixation systems face challenges in minimally invasive procedures, including difficulty in aligning and inserting cross-connectors without causing bone damage or neural injury, and they often require radiation exposure and extensive surgeon training.
Innovation Solution
A system using extenders and a magnetic targeting member with a tethering mechanism for securing cross-connectors to spinal rods, allowing for direct attachment and alignment without radiation, using a magnetic introducer to guide the targeting member through tissue, and a winding mechanism to facilitate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional open surgical technique is used to stabilize bone, then successful treatment of spinal instability is achieved, but large incisions and extensive muscle cutting are required causing lengthy healing time and considerable post-operative pain
Solution Approach 1:
The surgical procedure is divided into separate percutaneous steps: first inserting pedicle screws through small incisions, then separately inserting the rod through a different small incision using a rod inserter device. This segmentation allows each component to be placed through minimal incisions rather than requiring one large open incision, thereby reducing soft tissue damage while achieving the same stabilization result.
Solution Approach 2:
A rod inserter device acts as an intermediary tool that facilitates rod insertion through small percutaneous incisions. The device includes a rod holder that grips the rod and a delivery mechanism that pushes the rod through the incision and into the pedicle screws without requiring direct manual manipulation through large open wounds, thus minimizing tissue trauma while ensuring proper rod placement.
2Object-affected harmful factors
If percutaneous procedures are used to reduce soft tissue damage, then smaller incisions and reduced recovery time are achieved, but more novel and innovative approaches are required to perform complicated surgeries
Solution Approach 1:
The rod inserter device is designed as a multi-functional instrument that can perform multiple operations: it can insert rods of various sizes, accommodate different rod shapes (straight and contoured), and work with various pedicle screw configurations. This universality reduces the need for multiple specialized instruments, thereby managing device complexity while enabling versatile percutaneous spinal surgery.
Solution Approach 2:
The rod inserter device employs a nested structure where the rod holder is positioned within the delivery mechanism, and components are arranged in concentric or nested configurations. This nesting allows the device to maintain a compact profile during percutaneous insertion while providing access to multiple functional elements, thus managing complexity through space-efficient design.
3Ease of operation
If a fixed arch rod inserter is used to push the interconnecting rod, then rod insertion is achieved, but the rod cannot be directed around neural structures or bony obstructions increasing risk of collision and neurological damage
Solution Approach 1:
The rod inserter device incorporates a flexible or articulating shaft that can dynamically change its configuration during insertion. Rather than following a fixed rigid arch, the shaft can bend and redirect around neural structures and bony obstructions. This dynamic adaptability allows the rod to be guided safely through complex anatomical pathways while maintaining the ability to deliver the rod to the target location.
Solution Approach 2:
A flexible catheter or guidewire acts as an intermediary that can navigate around obstacles before the rod is inserted. This intermediary element creates a safe pathway through the tissue, allowing the subsequent rod insertion to follow a pre-established route that avoids neural structures and bony obstructions, thereby reducing the risk of neurological damage.
4Measurement precision
If image-based navigation systems are used to guide surgery, then accurate rod delivery is achieved, but radiation exposure to patient and surgical staff occurs
Solution Approach 1:
The system replaces image-based navigation (which relies on fluoroscopy and radiation) with a mechanical guidance system based on pre-planned trajectories and physical guides. The rod inserter device incorporates mechanical guides and alignment features that direct the rod along predetermined safe paths without requiring real-time imaging, thereby eliminating radiation exposure while maintaining delivery accuracy through mechanical precision.
Solution Approach 2:
Surgical trajectories and insertion paths are pre-planned and pre-established before the actual rod insertion. Guide wires or trajectory guides are placed beforehand to define safe pathways around neural structures. This preliminary action allows subsequent rod insertion to proceed without real-time imaging, achieving accurate delivery through pre-established mechanical guidance rather than radiation-based navigation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system reduces soft tissue damage, shortens surgery time, decreases x-ray exposure, and simplifies the procedure, minimizing complications and the need for extensive surgeon training while enhancing torsional stability of spinal implants.
Implementation Method 1
a magnetic introducer to guide the targeting member through tissue
Implementation Method 2
a winding mechanism to facilitate placement
Data Source
AI summary
The present invention describes a system suitable for guiding a cross-connector to a target area, such as spinal implants including spinal implant rods, within the body (in vivo) and method of using the same. The system includes a targeting member being constructed of, or having a steering material, which can be coupled to the cross-connector. The system further includes one or more devices which are used to maneuver the targeting member into position prior to attachment of the cross-connector. The cross-connector is traversed into position through the passageway created by the targeting member and secured to one or more spinal implant members.