Fluoroscopy-Guided Epidural Needle Path Marking for Angle Accuracy

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Solution Overview

Problem

Physicians face difficulty in inserting the epidural needle at the correct angle during spinal cord stimulation procedures, which affects the placement of SCS leads and the effectiveness of the treatment.

Innovation Solution

A device with adjustable arms and visible markers, compatible with fluoroscopy imaging, is used to guide the insertion of the epidural needle by marking a path on the skin surface, ensuring accurate placement of the needle and leads in the posterior epidural space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If physicians perform spinal cord stimulation procedures without visual guidance devices, then the procedure can be completed, but the accuracy of needle insertion angle and lead placement is reduced

Engineering Contradiction:
Improveneedle insertion angle accuracyVSAvoidprocedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a protractor device with fluoroscopy-visible markers as an intermediary tool between the physician and the patient's anatomy. This mediator provides visual reference lines and angle measurements during the needle insertion procedure, enabling precise angular positioning without requiring complex imaging interpretation skills. The device acts as a physical guide that translates complex spatial relationships into simple visual cues.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the reliance on physician skill and experience (human mechanical judgment) with a physical mechanical guide system. The protractor device with fixed angle markings and fluoroscopy-visible components provides objective mechanical reference for needle insertion angles, reducing variability between practitioners and eliminating the need for extensive training to achieve consistent results.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If physicians rely on experience and skill alone for needle insertion, then device complexity is minimized, but the probability of successful lead placement in the posterior epidural space decreases

Engineering Contradiction:
Improvelead placement success rateVSAvoidprocedure equipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs preliminary action by pre-marking the protractor device with fluoroscopy-visible indicators and angle references before the procedure begins. The device is prepared in advance with all necessary guidance information encoded in its structure, allowing the physician to simply align and read the pre-established references during needle insertion, rather than calculating angles or interpreting complex imaging data in real-time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes radiopaque materials that appear distinct under fluoroscopy imaging, creating visual contrast that highlights the protractor's reference lines and angle markings. This visual differentiation through radiopacity acts similarly to color changes, making the guidance features immediately recognizable and reducing the cognitive load required to interpret the imaging during the procedure.

Inventive Principle:
Principle #32Color changes

3Ease of operation

If the epidural needle is inserted at an incorrect angle, then the procedure can still be completed, but the SCS lead will not reach the posterior epidural space effectively

Engineering Contradiction:
Improveneedle insertion easeVSAvoidlead placement precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The protractor device serves as an intermediary reference system that simplifies the complex task of achieving precise needle insertion angles. By providing visual guide lines and angle markings that are directly visible under fluoroscopy, the device mediates between the simple act of needle insertion and the complex requirement for precise angular positioning, making the procedure easier while maintaining high precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 device enhances the accuracy of needle insertion, improving the probability of successful lead placement and ensuring effective spinal cord stimulation by providing visual guidance and adjusting the angle for optimal entry into the epidural space.

Implementation Method 1

the pin is a hollow cylinder made from a material that is visible in fluoroscopy imaging, and each hole of the first and second arms is surrounded by the material that is visible in the fluoroscopy imaging to visually depict the path in the fluoroscopy imaging for inserting the epidural needle

Methodology Applied
Scientific EffectFluoroscopy imaging: X-Ray

Data Source

PatentEP4255327B1Directional device for epidural needle
Publication Date: 2025.12.31 SPIRO MEDICAL INC
  • EP4255327B1 patent drawingFigure 1
  • EP4255327B1 patent drawingFigure 2~3
  • EP4255327B1 patent drawingFigure 4~5

AI summary

A device is described for marking a path on a skin surface for inserting an epidural needle into an epidural space. The device includes a first arm having one or more holes spaced apart along the length of the first arm. A pin is attached at the proximal end of the first arm. A second arm has a proximal end attached to the pin allowing the first and second arms to rotate about the pin to adjust an angle separating the first and second arms. The second arm has one or more holes spaced apart along the length of the second arm. The holes on the first and second arms provide locations for marking the path on the skin surface to insert the epidural needle.