Pediatric Mandibular Distractor Housing and Drive Mechanism

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Solution Overview

Problem

Infants with micrognathia and associated congenital craniofacial syndromes face airway obstruction and feeding difficulties due to a small mandible, which traditional methods like tracheostomy cannot effectively address without significant morbidity.

Innovation Solution

A pediatric mandibular distractor with a housing member, fixed and moveable footplates, and a drive rod mechanism that allows for controlled longitudinal advancement of the moveable footplate to lengthen the mandible, promoting bone growth and avoiding the need for tracheostomy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional tracheostomy is performed to address airway obstruction, then airway patency is improved, but perioperative morbidity and postoperative complications increase

Engineering Contradiction:

Improveairway patencyVSAvoidperioperative morbidity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The mandibular distraction device performs preliminary action by lengthening the mandible before airway obstruction becomes critical. The device is implanted and activated to gradually advance the mandible forward, which in turn pushes the tongue base anteriorly, preventing airway obstruction before it occurs and avoiding the need for tracheostomy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The distraction device acts as an intermediary between the mandible and the airway. By mechanically lengthening the mandible through the distraction mechanism, the device indirectly resolves the airway obstruction problem caused by tongue base prolapse, providing a intermediate solution that avoids both tracheostomy and direct tongue base surgery

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of repair

If the housing member is designed to minimize tissue ingrowth for easy removal, then device removal is facilitated, but bone anchoring strength may be reduced

Engineering Contradiction:

Improvedevice removalVSAvoidbone anchoring strength

Core Design Contradiction:

Ease of repairVSStrength

Solution Approach 1:

The housing member employs local quality by having different surface characteristics in different regions. The lateral surface that contacts bone has minimal protrusions to reduce tissue ingrowth, while the footplates have specific geometric features (such as slots and contours) that provide adequate anchoring. This localized differentiation allows easy removal from the main bone while maintaining secure attachment at the footplate-bone interface

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The device design accommodates dynamic changes in the surgical site. The housing member's smooth lateral surface allows for dynamic adjustment and easy removal after the distraction phase is complete, while the footplates maintain stable bone anchoring throughout the distraction process. The design transitions from a need for secure anchoring during distraction to easy removal after treatment

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If the drive rod mechanism allows controlled longitudinal advancement, then mandible lengthening precision is improved, but device complexity increases

Engineering Contradiction:

Improvemandible lengthening precisionVSAvoiddrive mechanism complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The drive rod mechanism replaces complex electronic or computerized control systems with a simpler mechanical threading system. The threaded drive rod engages with the moveable footplate through the elongated slot, providing controlled longitudinal advancement through pure mechanical means. This substitution maintains precision while reducing overall device complexity by eliminating the need for motors, sensors, or electronic controls

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical 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 distractor effectively addresses airway obstruction and feeding difficulties by lengthening the mandible, reducing perioperative morbidity and enabling early decannulation, while minimizing tissue ingrowth and facilitating easy removal.

Implementation Method 1

The threaded portion may engage with the threaded bore of the moveable footplate through the elongated slot

Methodology Applied

Scientific EffectThreaded engagement: Screw

Data Source

PatentEP2735276B1Pediatric internal mandibular distractor

Publication Date: 2018.09.05 STRYKER EUROPEAN HOLDINGS I LLC

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AI summary

A pediatric mandibular distractor comprising a housing member elongating along a longitudinal axis, the housing member having at least one elongated slot elongating along at least a portion of the longitudinal axis and opening laterally through at least a side portion of the housing member; at least one fixed footplate attached to the housing member; a drive rod; and at least one moveable footplate engageable with the drive rod through the elongated slot by a connector. Wherein, when the fixed and moveable footplates are attached to the respective first and second bone surfaces, a bottom portion of the housing member is proximate to the first and second bone surfaces, and the side portion is further from the bone surfaces than the bottom portion in a direction transverse to the longitudinal axis. Methods of assembling and installing the exemplary pediatric mandibular distractor summarized above are also disclosed.