Medialized PLIF Retractor Access for Reduced Muscle Stripping

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Solution Overview

Problem

Traditional posterior lumbar interbody fusion (PLIF) procedures require extensive muscle stripping and exposure to the transverse process, leading to increased morbidity and challenges in implantation of fixation hardware.

Innovation Solution

A medialized PLIF exposure technique using a retractor with dual translating racks and asymmetric blades that minimize muscle stripping, allowing for precise and stable access to the spine, facilitated by a bone anchor and reversible interbody implant for bilateral placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional PLIF exposure is used to access the intervertebral disc space, then adequate exposure and access to the spine is achieved, but extensive muscle stripping is required leading to increased morbidity

Engineering Contradiction:

Improvemuscle stripping and morbidityVSAvoidaccess to spine

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The retractor system is divided into multiple independent components: a retractor body, multiple retractor blades, and a dual translating rack mechanism. This segmentation allows the retractor to be configured with different blade arrangements to access the spine through smaller incisions without requiring extensive muscle stripping, while maintaining adequate exposure through the modular blade configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dual translating rack mechanism enables movement in multiple dimensions simultaneously, allowing the retractor blades to be positioned and adjusted in both lateral and vertical directions. This multi-dimensional adjustment capability provides precise access to the spine through smaller incisions, reducing the need for extensive muscle stripping while maintaining adequate surgical exposure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If traditional PLIF exposure is used, then adequate access to the transverse process is achieved, but the exposure area is large requiring more tissue disruption

Engineering Contradiction:

Improvetissue traumaVSAvoidexposure area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The retractor system employs localized retraction forces through individual blades that can be independently positioned. Each blade creates a focused retraction zone rather than requiring broad exposure, allowing precise access to the spine through minimal tissue disruption. The dual translating rack enables localized adjustment of each blade's position to match the specific surgical requirements.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dual translating rack mechanism provides dynamic adjustment capability, allowing the retractor blades to be moved and repositioned during the procedure. This dynamic system enables the surgeon to optimize the exposure area and blade positions in real-time based on anatomical variations, reducing overall tissue trauma while maintaining adequate access to the target area.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If medialized PLIF exposure is used with a retractor, then muscle stripping is reduced, but the retractor mechanism becomes more complex

Engineering Contradiction:

Improvemuscle strippingVSAvoidretractor mechanism

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The retractor body serves multiple functions: it houses the dual translating rack mechanism, provides attachment points for multiple retractor blades, and acts as the structural framework for the entire device. This multi-functionality consolidates what would otherwise be separate components into a single integrated unit, reducing the number of separate parts while maintaining the complex functionality needed for medialized exposure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The retractor blades are nested within the retractor body structure, with each blade having a dedicated receptacle in the retractor body. The dual translating rack mechanism is nested within the retractor body framework. This nesting arrangement organizes the complex components in a compact configuration, making the overall device more manageable while maintaining the sophisticated mechanism required for minimally invasive access.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Stability of the object's composition

If a dual translating rack retractor is used, then pressure distribution is equalized on both sides, but the device complexity increases

Engineering Contradiction:

Improvepressure distributionVSAvoiddual translating rack mechanism

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The dual translating rack mechanism merges the control of both retractor blades into a single integrated system. By combining the translation and locking functions into one mechanism, the design reduces the number of separate control components while maintaining the ability to equalize pressure distribution on both sides of the access corridor. The shared rack structure allows simultaneous adjustment of both blades with coordinated movement.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250288287A1Systems and methods for performing spine surgery

Publication Date: 2025.09.18 NUVASIVE INC

AI summary

This application describes surgical instruments and implants for building a fixation construct across one or more segments of the spinal column during a lumbar interbody fusion (LIF) procedure.