Cannulated Bone Screw Assembly for Cement-Backed Spinal Fixation
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Solution Overview
Problem
Existing medical instruments and screws are inadequate for combined operative procedures of spinal fusion, vertebroplasty, and pediculoplasty, particularly in cases of osteoporosis, as they fail to efficiently drive screws into cement mass without causing complications and do not facilitate easy removal.
Innovation Solution
A treatment device comprising a cylindrical driver, an inner sleeve, and a guide pin, which allows the screw to be driven into cement-filled bone with reduced instrument burden and facilitates easy removal by integrating the screw, driver, and inner sleeve through a unique thread and protrusion mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw is driven into cement mass after vertebroplasty using conventional instruments, then the screw can be inserted to provide internal fixation, but the procedure requires multiple instrument replacements and increases operational complexity
Solution Approach 1:
The patent combines the driver and inner sleeve into a single integrated instrument assembly that remains connected throughout the procedure. The driver fits onto the screw head while the inner sleeve is inserted through the screw, creating a unified tool system that eliminates the need to separate and replace instruments between cement injection and screw driving steps.
Solution Approach 2:
The integrated driver-inner sleeve assembly serves multiple functions: it facilitates cement injection through the inner sleeve, enables screw driving through the driver, and allows for potential screw removal. This multi-functional design reduces the number of specialized instruments needed and simplifies the overall surgical procedure.
2Reliability
If conventional screws are used in vertebroplasty procedures, then the screws can be driven into bone, but removal of the screws becomes difficult after cement hardening
Solution Approach 1:
The patent incorporates a protrusion on the inner sleeve that engages with a corresponding feature on the screw before the cement fully hardens. This preliminary engagement creates a controlled connection that allows for future removal of the screw-cement assembly as a unit, or facilitates easier separation once the procedure is complete and the bone has healed.
3Reliability
If multiple instruments are used for cement injection and screw driving, then each function can be optimized, but the surgical procedure time and complexity increase
Solution Approach 1:
By merging the driver and inner sleeve into a single connected assembly, the patent eliminates the time required to detach one instrument and attach another between cement injection and screw driving. The integrated design allows seamless transition between functions while maintaining the specialized capabilities of each component.
Data Source
AI summary
This invention relates to a treatment device suitable for combined operative procedure of vertebroplasty and pediculoplasty. A treatment device includes a cylindrical driver capable of driving a screw into bone, an inner sleeve capable of being inserted into the driver, and a guide pin capable of being inserted into the inner sleeve, and is configured as follows. The screw includes on an outer wall (outer circumference) a thread that can tap into bone or cement, and a through hole that allows the inner sleeve to pass from a head to a tip. The driver can fit onto the head of the screw and when moved along the central axis and be joined to the screw, so as to transmit torque about the central axis to the screw. The inner sleeve includes a notch which protrudes, when the inner sleeve is inserted from the distal end of the driver in a state in which the screw and the driver are joined together, protrudes more proximally than a tip of the screw, preventing removal of the screw.