Pressure-Sensitive Cervical Disc Trial Instrument
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Solution Overview
Problem
Current trialing instruments for selecting properly sized cervical prosthetic discs lack objective measures, leading to potential over-sizing issues that can result in significant drops in spinal range of motion, as selecting an implant that is too tall by as little as 1 mm can cause a 15% drop in cervical spine range of motion and a 50% drop at the corrected level, effectively creating a quasi-fusion.
Innovation Solution
Development of pressure-sensitive trialing instruments with film that provides objective visual feedback through color density changes, allowing surgeons to assess the fit of the implant within the vertebral disc space, utilizing Fujifilm Prescale film that captures pressure readings and offers a computerized analysis for precise implant size selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional trialing instruments are used, then the procedure is simple and quick, but the measurement precision and objectivity are insufficient leading to potential over-sizing
Solution Approach 1:
The patent applies color-changing pressure-sensitive film to the end plates of trialing instruments. When the trial implant is inserted, pressure causes microbubbles in the film to burst, creating color density variations that objectively indicate the fit quality and vertebral endplate coverage. This visual feedback system transforms subjective surgeon judgment into objective measurable data, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The pressure-sensitive film acts as an intermediary between the trial implant and the surgeon's assessment. Instead of the surgeon directly evaluating fit based on experience, the film mediates by converting pressure distribution into visual color patterns, providing objective feedback that bridges the gap between simple instrumentation and precise measurement.
2Measurement precision
If multiple x-ray exposures are used for trialing, then the measurement accuracy improves, but the loss of time and patient exposure to radiation increases
Solution Approach 1:
The pressure-sensitive film serves as an intermediary that provides immediate visual feedback on vertebral endplate coverage during the trial insertion, eliminating the need for multiple x-ray exposures. The color density patterns directly indicate coverage quality, allowing surgeons to assess fit accuracy without time-consuming imaging procedures.
Solution Approach 2:
The patent replaces the mechanical/radiological imaging system (x-ray exposures) with a chemical/optical system (pressure-sensitive film color changes). This substitution provides equivalent or superior measurement precision for vertebral endplate coverage assessment while eliminating radiation exposure and reducing procedure time.
3Reliability
If surgeon judgment and experience are relied upon, then the device complexity remains low, but the measurement precision and reliability are insufficient
Solution Approach 1:
The pressure-sensitive film provides immediate visual feedback on implant fit quality through color density patterns. This feedback mechanism transforms subjective surgeon judgment into objective, reliable data about vertebral endplate coverage and pressure distribution, significantly improving the reliability of implant size selection while adding minimal complexity to the trialing system.
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 pressure-sensitive trialing instruments enable surgeons to select the appropriate implant size objectively, minimizing the loss of range of motion and ensuring proper vertebral endplate coverage, thereby maintaining native spinal mobility.
Implementation Method 1
the pressure sensitive material provides an objective visual feedback to the surgeon regarding the fit of the trial within the vertebral disc space. In an example, the end plate surfaces of the trialing instruments can be covered in a single use pressure sensitive film that creates a pressure map through a color density created when the applied pressure bursts microbubbles of ink within the film.
Data Source
AI summary
An implant-trialing instrument for objectively determining a recommended implant size based at least in part on results of inserting a pressure sensitive trial implant into the intervertebral space. The trial implant instrument can include a handle coupled to a pressure sensitive trial. The handle can include an elongate shaft. The pressure sensitive trial implant can be disposed on a distal end of the elongate shaft and include a superior end plate surface configured to engage a first end plate of a first vertebral body and an inferior end plate configured to engage a second end plate of a second vertebral body. The pressure sensitive trial implant also includes a pressure sensitive film disposed on at least one of the superior end plate and the inferior end plate.