Cannulated Bone Screw and Driver for Cemented Spinal Fixation
Find Innovative SolutionsGenerate Solutions
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 complicate cement injection, increase instrument reuse burdens, and complicate screw removal due to cement hardening.
Innovation Solution
A treatment device comprising a cylindrical driver, inner sleeve, and guide pin that allows for driving a screw into cement without additional instruments, with features like self-tapping threads and a guide pin mechanism to facilitate integration and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cement is injected into the vertebral body and then a screw is driven into the cement, then the screw provides internal fixation and the cement provides structural support, but the cement hardens over time making screw removal difficult
Solution Approach 1:
The screw is divided into distinct functional segments: a threaded portion for bone engagement, a central through-hole for cement injection, and a head portion for driver engagement. This segmentation allows the screw to provide fixation while maintaining removability through the through-hole access
Solution Approach 2:
The central through-hole acts as an intermediary structure that allows cement to be injected through the screw body during insertion, creating a channel that later facilitates screw removal by allowing access to the screw shaft from the vertebral body interior
2Reliability
If multiple instruments are used for cement injection and screw insertion, then each function can be performed precisely, but the number of instruments increases and reuse burden increases
Solution Approach 1:
The screw design merges multiple functions into a single instrument: it serves as both the fixation device and the conduit for cement injection. The driver head combines screw driving capability with cement injection access, eliminating the need for separate injection needles or catheters
Solution Approach 2:
The screw structure serves multiple purposes: providing mechanical fixation through threading, serving as a conduit for cement injection through the central hole, and facilitating future removal through the same hole. The driver system similarly provides both driving and injection functions
3Stability of the object's composition
If a screw is driven into hardening cement, then the screw achieves stable fixation, but the integration between screw and cement complicates future removal
Solution Approach 1:
The central through-hole is created in the screw during manufacturing, preliminarily establishing a removal pathway before the cement hardens. This preliminary structure allows future removal tools to access the screw shaft through the vertebral body interior, bypassing the hardened cement interface
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.