Bone Anchor Insertion Instruments With Stylet Retraction Control
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Solution Overview
Problem
Conventional bone anchor insertion instruments risk undesired deep advancement into bone, leading to potential damage and trauma due to the stylet continuing to advance beyond the bone anchor assembly, necessitating improved instrumentation for controlled insertion.
Innovation Solution
A surgical instrument with a handle assembly that can be configured to rotate the elongate shaft and translate the stylet relative to the bone anchor assembly, featuring a clutch mechanism to ensure the stylet retracts as the bone anchor is driven into bone, preventing further advancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stylet continues to advance ahead of the bone anchor assembly during insertion, then the bone anchor can be driven deeper into bone, but this causes accidental advancement of the bone anchor assembly too deep into bone leading to damage to bone and underlying tissue
Solution Approach 1:
The system uses a feedback mechanism where the stylet's position is continuously monitored relative to the bone anchor assembly. When the stylet reaches a predetermined position indicating the bone anchor is fully inserted, the system automatically stops further advancement or triggers a warning, preventing excessive insertion depth and potential tissue damage while maintaining efficient insertion speed
Solution Approach 2:
A depth indicator or positioning mechanism serves as an intermediary between the stylet and the bone anchor assembly, providing real-time information about the relative positions. This intermediary component allows the surgeon to control the insertion depth precisely, preventing the stylet from advancing too far ahead of the bone anchor while maintaining productive insertion rates
2Manufacturing precision
If the stylet is advanced to the desired depth before driving the bone anchor assembly, then the bone anchor can be positioned accurately, but any further advancement of the stylet can lead to further accidental advancement of the bone anchor assembly into bone
Solution Approach 1:
The system employs dynamic control mechanisms that adjust the relationship between the stylet and bone anchor assembly during insertion. The stylet can be advanced independently for positioning, but the bone anchor assembly's advancement is dynamically linked to the stylet's position through a controlled coupling mechanism that prevents excessive insertion once the desired depth is reached
Solution Approach 2:
The insertion process is segmented into distinct phases: first, the stylet is advanced to the desired depth for positioning; second, the bone anchor assembly is driven along the stylet's path to the final position. This segmentation allows precise positioning followed by controlled advancement, with the stylet's position serving as a reference point that prevents further accidental advancement of the bone anchor assembly
Data Source
Figure 1A~1C
Figure 1D
Figure 1E
AI summary
Surgical instruments and methods for implanted bone anchor assemblies into bone are disclosed herein. In one exemplary embodiment, an instrument is provided having an anchor drive assembly and a stylet assembly. The anchor drive assembly can have a first handle and an elongate shaft having a distal tip configured to couple to a bone anchor assembly. The stylet assembly can have a second handle and a stylet extending through the elongate shaft. The instrument can have a disengaged position and an engaged position such that rotation of the first handle is effective to drive the bone anchor assembly into bone only when the instrument is in the engaged position, and rotation of the second handle is effective to cause axial translation of the stylet relative to the elongate shaft.