Cement Applicator with Prechamber and Guide Mandrel
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Solution Overview
Problem
Current cement applicators for bone cement in prosthesis implantation lack the ability to ensure a uniform layer thickness and controlled distribution, leading to air pockets, incomplete prosthetic fits, and increased risk of aseptic loosening and bone necrosis due to variability in surgeon technique and manual application.
Innovation Solution
A cement applicator with a universal connection for mixing systems, an antechamber with multiple exit holes for controlled cement flow, a guide mandrel for uniform distribution, and a torsion protection guide to prevent twisting and ensure even cement application, along with a pressure regulating seal to maintain constant pressure and prevent cement leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bone cement is applied manually by surgeons, then the application process is simple and quick, but the layer thickness is non-uniform and cement distribution is uncontrolled
Solution Approach 1:
A cement applicator device serves as an intermediary between the mixing system and the bone surface. The applicator includes a prechamber that receives cement from the mixing system and multiple outlet holes that distribute the cement uniformly across the bone surface, eliminating the need for manual application while ensuring consistent layer thickness.
Solution Approach 2:
The applicator divides the cement delivery function into multiple outlet holes (at least three) distributed across the prechamber. This segmentation allows simultaneous cement application at multiple locations, ensuring uniform distribution and controlled thickness across the entire bone surface.
2Quantity of substance
If less viscous bone cement is used, then deeper penetration into the bone is achieved, but the application becomes significantly more difficult and time-consuming
Solution Approach 1:
The prechamber acts as an intermediary that receives the less viscous cement from the mixing system and controls its flow through multiple outlet holes. This intermediary structure allows the surgeon to benefit from deep penetration capability while the device handles the difficulty of applying less viscous material uniformly.
Solution Approach 2:
The cement is pre-loaded into the prechamber before application to the bone. This preliminary action allows the cement to be contained and controlled in a confined space, making it easier to manage less viscous cement and ensuring it is applied in a controlled manner through the outlet holes.
3Strength
If excessive cement is applied to ensure sufficient penetration, then cement-bone interface strength is improved, but heat necrosis and bone damage occur
Solution Approach 1:
The cement application is segmented into multiple outlet holes that distribute cement across the bone surface. This segmentation ensures sufficient cement penetration for strong bonding while preventing excessive cement accumulation that would generate harmful heat and cause bone necrosis.
Solution Approach 2:
Each outlet hole applies cement to a specific local area of the bone surface with controlled quantity and distribution. This local quality control ensures adequate penetration strength at each location while preventing excessive cement buildup that would lead to heat necrosis.
4Adaptability or versatility
If cement application is performed without standardized control, then the procedure is flexible and adaptable, but air pockets form and prosthesis fit is compromised
Solution Approach 1:
The prechamber serves as an intermediary that standardizes the cement delivery process. It receives cement from the mixing system and ensures consistent distribution through multiple outlet holes, eliminating air pockets and ensuring reliable prosthesis fit while maintaining adaptability to different surgical situations.
Solution Approach 2:
The cement is pre-loaded into the prechamber in a controlled manner before application. This preliminary action ensures that the cement is ready for immediate uniform distribution through the outlet holes, preventing air pocket formation and ensuring reliable prosthesis fit.
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
The cement applicator ensures a uniform layer of bone cement on the bone surface, enhancing the reliability of the bone-prosthesis connection by providing consistent cement penetration and reducing the risk of air pockets and bone damage, thereby improving the stability and longevity of the implant.
Implementation Method 1
The prechamber (11) comprises at least one exit hole (5)... through which the bone cement (2) can be pressed out of the prechamber (11)
Implementation Method 2
the guide mandrel (6)... is designed to penetrate the closure of a mixing system, so that bone cement (2) from the mixing system can flow into the prechamber (11)
Implementation Method 3
The seal (10) is designed as a sealing lip or sealing bead and serves to reduce the contact area between the outlet region and the bone. This ensures a constant pressure within the cement.
Implementation Method 4
When PMMA and MMA come into contact, polymerization begins. For example, the bone cement hardens and sets completely within a time interval of 7–15 minutes.
Data Source
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AI summary
Cement applicator (100) for introducing bone cement during the implantation of prostheses into bone, comprising at least a universal connection (3) for connection to a mixing system, a pre-chamber (11) consisting of a first side (11a), a second side (11b) and a sleeve (11c) which fluid-tightly connects the first side (11a) and the second side (11b), wherein the first side (11a) is fluid-permeable to the universal connection (3) and is suitable for receiving bone cement from a mixing system, and wherein the second side (11b) is arranged opposite the first side (11a) and has at least one outlet hole (5) through which the bone cement can exit, an outlet area (9) which is arranged adjacent to the pre-chamber (11), wherein the second side (11b) of the pre-chamber forms the first side (9a) of the outlet area (9).such that the outlet area (9) is connected to the pre-chamber (9) via the at least one outlet hole (5) in a fluid-permeable manner, so that bone cement can flow from the pre-chamber (11) into the outlet area (9), wherein the outlet area (9) is further configured such that its second side (9b) opposite the pre-chamber (11) is open and can be positioned on a bone, a torsion protection guide (8) is arranged between the pre-chamber (11) and the outlet chamber (9) so that the cement applicator (100) can rest flat on a bone. The cement applicator (100) further comprises a guide pin (6) which is arranged such that its first end (6a) projects into the pre-chamber (11) in such a way that it can penetrate a closure of a mixing system through at least one universal connection (3), so that bone cement can enter the pre-chamber (11) from the mixing system via the universal connection (3).wherein a second end (6b) of the guide pin (6) opposite the first end can be attached within a prepared medullary canal of a bone.