Stimulation Lead Stylet Tube Nested Design

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional spinal cord stimulation systems require invasive surgical procedures for lead placement, which can result in complications such as nerve damage, infection, and high costs, and often fail to provide adequate pain relief due to the complexity of accessing and stimulating specific anatomical targets like dorsal root ganglions.

Innovation Solution

A system comprising a lead with a shaft and a sheath that can bend to navigate through a needle into the epidural space, using a stylet to guide the lead to the spinal nerve, allowing for precise positioning of electrodes near or on the target anatomy, such as dorsal root ganglions, with a design that minimizes trauma and maximizes flexibility to reduce complications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional surgical procedures are used for lead placement, then the lead can be positioned in the epidural space, but the procedure causes nerve damage, infection, and high costs

Engineering Contradiction:

Improvelead placement effectivenessVSAvoidnerve damage and infection

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stylet tube is nested within the lead shaft, allowing the stylet to be inserted and removed from the lead. This nested configuration enables the lead to be delivered through a needle tract while the stylet provides steering control, reducing the need for extensive surgical exposure and minimizing trauma to neural tissue

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The stylet tube acts as an intermediary component between the operator and the lead. By manipulating the stylet within the stylet tube, the operator can guide the lead to the target location through the needle tract without direct surgical manipulation of the lead itself, reducing the risk of infection and nerve damage

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the lead is made flexible to navigate through the needle, then the lead can reach the epidural space, but the lead may kink or deform

Engineering Contradiction:

Improvelead flexibilityVSAvoidlead shape stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The lead shaft has different mechanical properties at different locations. The distal portion of the shaft is more flexible to navigate the needle tract and conform to the epidural space, while the proximal portion maintains greater structural integrity. The stylet tube provides localized support where needed without making the entire lead rigid

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The lead's mechanical properties are dynamically adjusted during implantation. The stylet is inserted to provide temporary stiffness for navigating the needle tract, then removed once the lead is positioned, allowing the lead to flex and conform to the epidural space without permanent deformation or kinking

Inventive Principle:

Principle #15Dynamics

3Stability of the object's composition

If the stylet tube is fixedly coupled throughout the shaft, then the lead maintains its shape, but the stylet cannot be removed for lead repositioning

Engineering Contradiction:

Improvelead shape stabilityVSAvoidlead repositioning capability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The coupling between the stylet tube and shaft is segmented into multiple zones: a distal fixed coupling to maintain shape during navigation, a middle movable coupling zone allowing stylet extraction, and a proximal fixed coupling for structural support. This segmentation enables both shape stability during implantation and repositioning capability afterward

Inventive Principle:

Principle #1Segmentation

4Object-affected harmful factors

If the lead shaft is made smaller to fit through the needle, then the procedure is less invasive, but the lead may be more difficult to manipulate

Engineering Contradiction:

Improvesurgical traumaVSAvoidlead manipulability

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The stylet tube serves as an intermediary that provides manipulative control for the small-diameter lead. By manipulating the stylet rather than the lead directly, the operator can guide the thin lead through the needle tract and into the epidural space with precision, overcoming the difficulty of manipulating a small, flexible object

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2641633B1Stimulation lead with stylet tube

Publication Date: 2018.04.04 SPINAL MODULATION INC

Figure 1A
Figure 1B
Figure 2~4

AI summary

A stimulation lead is provided for neuromodulating portions of the spinal nerves, particularly one or more dorsal root ganglions (DRGs), to treat chronic pain while causing minimal deleterious side effects such as undesired motor responses. The stimulation lead (100) comprises: a shaft (103) comprising a tube (172) having a distal end (101) and a proximal end (105); a stylet tube (174) disposed within the shaft; at least one electrode (102) disposed near the distal end of the shaft; at least one conductor cable (182) extending from the at least one electrode toward the proximal end of the shaft; and optionally a tensile element (188) fixedly coupled to the shaft in at least one location along the shaft. The stylet tube (174), the tensile element (188), and the conductor cables (182) extend through the shaft tube (172) and are free to move therein for allowing allowing greater flexibility in bending and lower applied forces to achieve reduced curve radii in the lead.