Flush Fiducial Marker Base for Skull Implantation
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Solution Overview
Problem
Fiducial marker devices cause discomfort to patients due to the upwardly-extending shaft and external threads, which can irritate the scalp and lead to prolonged discomfort between preoperative imaging and surgical procedures.
Innovation Solution
Design of fiducial marker assemblies with anchoring bases that are implanted flush with or recessed from the skull surface, eliminating the need for an upwardly-extending shaft and using self-tapping or externally threaded portions for secure implantation, along with registration receptacles and plugs to prevent debris accumulation and reduce irritation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an upwardly-extending shaft with external threads is used for fiducial marker implantation, then secure anchoring in the skull is achieved, but patient discomfort and scalp irritation increase
Solution Approach 1:
The patent removes the upwardly-extending shaft and external threads from the fiducial marker design. Instead, it uses a base plate with internally threaded receptacles that receive the fiducial markers, eliminating the source of scalp irritation while maintaining secure anchoring through the threaded receptacle design.
Solution Approach 2:
The patent inverts the traditional threading approach by moving the external threads from the upwardly-extending shaft to the base plate itself. The base plate contains internally threaded receptacles that engage with the fiducial markers, reversing the location and direction of the threading to eliminate scalp contact with threads.
2Reliability
If an upwardly-extending shaft is used for fiducial marker implantation, then secure implantation is achieved, but scalp closure becomes difficult and patient comfort decreases
Solution Approach 1:
The patent removes the upwardly-extending shaft that protrudes from the skull surface. The base plate is designed to sit flush against the skull with receptacles that receive the fiducial markers horizontally or at an angle, eliminating the protruding element that interferes with scalp closure.
Solution Approach 2:
The patent changes the orientation of the fiducial marker receptacles from vertical (requiring upwardly-extending shafts) to horizontal or angled receptacles in the base plate. This inversion allows the scalp to close naturally over the implantation site while maintaining secure engagement of the fiducial markers.
3Measurement precision
If multiple fiducial markers with shafts are implanted in the skull, then recognizable landmarks are defined for image guidance, but prolonged patient discomfort occurs between imaging and surgery
Solution Approach 1:
The patent removes the upwardly-extending shafts that cause prolonged discomfort. The base plate design allows fiducial markers to be received horizontally or at an angle, eliminating the protruding elements that cause scalp irritation during the extended period between imaging and surgery.
Solution Approach 2:
The patent inverts the implantation approach by using a base plate with internally threaded receptacles that receive the fiducial markers, rather than using upwardly-extending shafts with external threads. This inversion maintains precise landmark definition while eliminating the source of prolonged patient discomfort.
4Strength
If externally threaded shafts are used for fiducial markers, then secure engagement with the skull is achieved, but scalp irritation and discomfort increase
Solution Approach 1:
The patent removes the externally threaded shafts that contact the scalp and cause irritation. The external threading is relocated to the base plate, where internally threaded receptacles engage with the fiducial markers, separating the engagement function from the scalp-contacting surface.
Solution Approach 2:
The patent inverts the threading configuration by placing internal threads in the base plate receptacles rather than external threads on the fiducial marker shafts. This inversion maintains strong engagement while eliminating the externally threaded surface that causes scalp irritation.
Data Source
AI summary
This document discusses, among other things, a fiducial marker assembly that includes an internally engagable base. The base is sized and shaped to be mounted flush to or recessed from an outer surface of a patient's skull, thereby reducing or avoiding patient discomfort. The fiducial marker assembly includes an imagable locator and a registration receptacle. A base insertion instrument is engaged to the base to attach the base to the patient's skull. In one example the base includes a faceted head, permitting a socket-like device to screw or unscrew the base into or out of the skull. In another example, the base includes at least one step or slot for engaging an insertion or extraction tool.