Nested Spinal Instrument Shaft for Ergonomic Pedicle Screw Alignment
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Solution Overview
Problem
Existing pedicle screw fixation systems, such as those using Jamshidi needles, lack ergonomic design, leading to hand cramping and radiation exposure during surgical procedures for spinal targeting and screw placement.
Innovation Solution
A minimally invasive spinal instrument with an outer and inner shaft configuration, featuring locking grooves and a locking knob, allowing for stable handling and minimizing radiation exposure by positioning the surgeon's hand and forearm out of the imaging line-of-sight, while enabling accurate pedicle screw placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Jamshidi needle is used for pedicle screw placement, then the alignment of pedicle screws can be achieved, but the surgeon's hand and forearm are exposed to radiation during imaging procedures and hand cramping occurs due to poor ergonomics
Solution Approach 1:
The patent introduces an intermediary device (the specialized needle holder with extended shaft) that mediates between the surgeon and the Jamshidi needle. This intermediary allows the surgeon to maintain a safe distance from the imaging field, eliminating direct radiation exposure to the hand and forearm while preserving alignment accuracy through the extended shaft design
2Measurement precision
If a Jamshidi needle is used for pedicle screw placement, then the alignment of pedicle screws can be achieved, but hand cramping occurs due to lack of ergonomic form factor
Solution Approach 1:
The patent segments the needle holder into distinct functional components: an extended shaft portion for positioning, a gripping mechanism for secure handling, and a locking system for stability. This segmentation allows each component to be optimized for its specific function, improving overall ergonomics while maintaining alignment precision
Solution Approach 2:
The patent adds dimensional extension to the needle holder shaft, creating an extended reach that changes the spatial relationship between the surgeon's hand and the needle tip. This dimensional change improves ergonomics by allowing the surgeon to operate from a more comfortable position while maintaining precise control over needle placement
3Ease of manufacture
If the needle holder design is simplified, then manufacturing cost is reduced, but stability and precision of needle placement are compromised
Solution Approach 1:
The patent employs a nested structure where the inner shaft is positioned within the outer shaft, with locking grooves and clamps creating a hierarchical assembly. This nested design provides inherent stability and precision through the interlocking geometry while remaining manufacturable using standard machining processes
Data Source
AI summary
A minimally invasive spinal instrument and method for use of the same are disclosed. In some embodiments, a body includes an outer shaft and an inner shaft. A passageway accepts the inner shaft such that the outer shaft at least partially encloses the inner shaft. Each of the outer shaft and the inner shaft have spaced rings with locking grooves interleaved therewith. Each set of locking grooves is sized to accept a clamp such that the spaced rings mitigate longitudinal sliding of the clamp. A locking knob selectively secures the outer shaft and inner shaft thereto. A tip is removably secured to the inner shaft. In a single shaft configuration, in response to the locking knob being selectively disengaged from the outer shaft, the inner shaft and the locking knob are separated from the outer shaft such that the passageway is accessible to accept a metallic wire therethrough.