Bidirectional Mandibular Distractor with Force-Limited Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mandibular distractors lack adequate adjustment control, which can lead to issues such as unintended movement of bone surfaces during distraction procedures, particularly in pediatric patients with conditions like Pierre Robin Sequence, where precise control is crucial for avoiding complications like airway obstruction and feeding difficulties.
Innovation Solution
A mandibular distractor with a housing and drive rod mechanism that includes engaging portions configured to prevent relative rotation between the housing and drive rod unless a predetermined force is applied, allowing for controlled bidirectional adjustment of the distractor to manage bone surface movement effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-directional ratchet mechanism is used in the distractor, then the distractor can prevent reverse distraction and maintain position, but the distractor cannot be adjusted bidirectionally and lacks flexibility for fine-tuning
Solution Approach 1:
The patent applies a dynamic engagement mechanism where the drive rod can be engaged or disengaged from the housing based on applied force. When a predetermined force is applied, the drive rod disengages, allowing bidirectional rotation. When force is removed, the mechanism re-engages to maintain position. This dynamic behavior resolves the contradiction by providing both position maintenance and adjustment flexibility.
Solution Approach 2:
The patent changes the engagement parameter of the drive rod and housing based on applied force. Below a predetermined force threshold, the mechanism maintains engagement for position stability. Above the threshold, engagement is lost to enable bidirectional adjustment. This parameter-based control resolves the contradiction between reliability and adaptability.
2Reliability
If a locking screw mechanism is used to lock the distracted position, then the distractor can maintain position stability, but the distractor requires unlocking before further distraction and reduces ease of operation
Solution Approach 1:
The drive rod mechanism serves itself by automatically engaging and disengaging based on the force applied during rotation. No separate locking or unlocking action is required - the same rotational mechanism that provides stability also enables adjustment when force is applied. This self-service approach resolves the contradiction between position stability and ease of operation.
3Adaptability or versatility
If the drive rod is allowed to rotate freely in both directions, then the distractor provides adjustment flexibility, but unintended rotation and movement can occur reducing control precision
Solution Approach 1:
The patent applies preliminary anti-action by designing the drive rod mechanism to automatically resist unintended rotation through engagement with the housing. The mechanism is pre-configured to engage and prevent rotation unless a predetermined force is applied in the intended direction. This preliminary protective action resolves the contradiction between flexibility and precision.
Data Source
AI summary
A distractor, such as a pediatric mandibular distractor, includes a housing member elongated along a longitudinal axis. At least one distal footplate is attached to the housing member. A drive rod and at least one proximal footplate configured to be driven by the drive rod are provided. A housing engaging member is configured to engage a drive rod engaging member to prevent the housing from being rotated in either a first or second direction of rotation relative to the drive rod when a rotational force less than a predetermined force is applied to the housing or drive rod. The drive rod can be rotated relative to the housing in either the first or second rotational direction when a force greater than the predetermined force is applied to the drive rod or the housing.