Cranial Flap Clamp with Nitinol Tensioning
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Solution Overview
Problem
Current methods for securing a bone flap to the skull during craniotomy procedures are either time-consuming, prone to injury, or result in an unappealing cosmetic appearance due to the use of drilling or bone plates and screws.
Innovation Solution
A cranial flap clamp system with a securing instrument featuring pivotally connected handles, gripping and tensioning arms, a crimping assembly, and a tension limiting mechanism, which allows for secure fixation of the bone flap without deep drilling or protruding hardware, using nitinol wires for controlled tension application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire drilling and twisting method is used to secure bone flap, then fixation is achieved, but procedure time increases and injury risk increases
Solution Approach 1:
Holes are pre-drilled through the skull and bone flap edges before the actual fixation process. This preliminary action prepares the pathway for the wire, eliminating the need for time-consuming drilling during the critical fixation phase and reducing overall procedure time while maintaining secure fixation.
Solution Approach 2:
A wire is introduced as an intermediary element that passes through the pre-drilled holes and is twisted to secure the bone flap to the skull. This intermediary mechanism provides reliable fixation without requiring direct mechanical connection methods that would increase procedure time or injury risk.
2Reliability
If bone plates and screws are used for fixation, then stable fixation is achieved, but cosmetic appearance deteriorates
Solution Approach 1:
The visible plate and screw components are extracted or removed from the final configuration. Instead of leaving protruding hardware on the skull surface, the wire fixation method uses minimal visible elements that pass through pre-drilled holes, eliminating the cosmetic defect of protruding plates and screws while maintaining fixation stability.
3Reliability
If deep drilling is performed for wire insertion, then fixation is achieved, but injury risk increases
Solution Approach 1:
Holes are carefully pre-drilled to the exact required depth and position before wire insertion. This preliminary preparation ensures that drilling is performed once with precise control rather than requiring deep, potentially dangerous drilling during the fixation phase, thereby reducing injury risk while achieving secure fixation.
4Reliability
If multiple holes are drilled for wire fixation, then secure attachment is achieved, but procedure complexity increases
Solution Approach 1:
The fixation process is segmented into distinct phases: pre-drilling of holes, wire insertion through the holes, and twisting to secure. This segmentation allows each step to be performed independently and efficiently, reducing overall procedure complexity while ensuring secure attachment through multiple fixation points.
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 system provides a faster, safer, and more aesthetically pleasing method for securing bone flaps, minimizing tissue damage and patient discomfort while ensuring stable fixation for healing.
Implementation Method 1
using nitinol wires for controlled tension application
Implementation Method 2
using nitinol wires for controlled tension application
Data Source
AI summary
The disclosed cranial flap clamp includes first and second clamping members and an extension member. A portion of the first member is positionable against inferior surfaces of a bone flap and skull and a portion of the second member is positionable against superior surfaces of the flap and skull. The extension member extends from the first member through the second member and fits between the flap and skull. Movement of either of the clamping members urges the inner surface of the first member against the inferior surfaces of the flap and skull and urges the inner surface of the second member against the superior surfaces of the flap and skull. The securing instrument includes features useful in cutting or crimping the extension member. The tension limiting assembly provides variable designs and combinations for limiting the tension placed on, and exerted by, the securing instrument during use.