Bone Screw Spacing Caliper for Minimally Invasive Rod Sizing

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Solution Overview

Problem

Minimally invasive surgical techniques face challenges in accurately determining the optimal size of implants due to tissue obstruction and visualization issues, leading to potential trauma, scarring, and prolonged recovery times, especially in spinal and neurosurgical applications.

Innovation Solution

A caliper system with a first arm and second arm connected by a pivot pin, featuring a graduated scale and indicator segment, is used to measure the spacing between bone screws, allowing for precise determination of the length of spinal rods needed to connect bone structures, facilitating accurate implantation without extensive tissue disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If minimally invasive surgical techniques are used to reduce tissue trauma and scarring, then patient recovery time is reduced and tissue damage is minimized, but accurate measurement and selection of implant size becomes difficult due to tissue obstruction and visualization issues

Engineering Contradiction:

Improvetissue trauma and scarringVSAvoidimplant size determination

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent introduces a caliper device as an intermediary measurement tool that can be inserted through the tissue to measure bone screw spacing. The caliper acts as a mediator between the surgeon and the bone structures, allowing accurate measurement without requiring direct visualization or extensive tissue disruption. The caliper includes a first arm that engages with a first bone screw and a second arm that engages with a second bone screw, with a scale and indicator mechanism that provides precise spacing measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the need for visual measurement and manual estimation with a mechanical measurement system. The caliper uses a pivot pin connecting two arms, with a graduated scale and indicator segment that mechanically measures the distance between bone screws. This mechanical system provides precise, objective measurement without relying on visual judgment through obstructed tissue.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If extensive tissue disruption is performed to access bone structures for implantation, then accurate visualization and measurement of the implantation location is achieved, but patient recovery time increases and tissue damage occurs

Engineering Contradiction:

Improveimplantation location visualizationVSAvoidrecovery time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The caliper device serves as an intermediary that enables measurement without direct tissue disruption. By inserting the caliper through minimal incisions, the device can measure bone screw spacing accurately without requiring extensive tissue removal or repositioning that would be needed for direct visual access.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent enables preliminary measurement of bone screw spacing before final implant placement. The caliper can be used to measure the spacing between bone screws through minimally invasive access, allowing the surgeon to determine the appropriate rod length in advance without committing to extensive tissue disruption.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If minimally invasive techniques are used to access bone structures, then tissue disruption is reduced, but the ability to accurately determine the optimal implant size is compromised

Engineering Contradiction:

Improvesurgical accessVSAvoidimplant size selection

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The caliper acts as a precision measurement intermediary that bridges the gap between minimally invasive access and accurate measurement. The device includes a first arm with a distal end that engages a first bone screw, a second arm with a distal end that engages a second bone screw, and a scale with an indicator segment that provides precise spacing measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces visual estimation and manual measurement with a mechanical measurement system. The caliper uses a pivot pin connecting two arms, with a graduated scale and indicator segment that mechanically measures the distance between bone screws, providing objective precision without requiring extensive tissue disruption for visualization.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10575918B2Apparatus and method for sizing a connecting element for positioning along a bone structure

Publication Date: 2020.03.03 WARSAW ORTHOPEDIC INC

AI summary

Apparatus and methods for measuring spacing between first and second bone screws engaged with first and second bone structures are provided. An apparatus comprises first and second arms operably engaged with a single pivot pin. The first arm includes a distal end adapted to engage the first bone screw, and a proximal end comprising a graduated scale. The second arm, operably engaged with the first arm via the single pivot pin, includes a distal end adapted to engage the second bone screw, and a proximal end comprising an indicator segment slidably engaged with the graduated scale. A position of the indicator segment relative to the graduated scale is therefore indicative of a spacing between the first and second bone screws.