Spinal Retractor Fluid Level Control for Clearer Endoscopic Resection

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Solution Overview

Problem

Minimally invasive spine surgery faces challenges with limited visibility and heat generation from powered instruments, particularly in procedures like transforaminal lumbar interbody fusion, due to blood and bone debris obstructing the field of view and the need for improved fluid management at the surgical site.

Innovation Solution

A surgical system with a retractor and integrated fluid management system, including inflow and outflow sources, sensors, and controllers to maintain a threshold fluid level, ensuring clear visualization and cooling by controlling fluid flow rates and turnover to manage debris and heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If manual instruments are used for disc preparation, then heat generation is reduced, but surgical efficiency and productivity are lowered

Engineering Contradiction:

Improveheat generationVSAvoidsurgical efficiency

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

A fluid delivery system acts as an intermediary between the powered instrument and the surgical site. The fluid serves as a heat transfer medium that absorbs heat generated by the powered instrument and carries it away from the surgical site, enabling the use of powered instruments while preventing excessive heat generation and tissue damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If powered surgical instruments are used, then surgical efficiency is improved, but heat generation and tissue damage increase

Engineering Contradiction:

Improvesurgical efficiencyVSAvoidheat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The fluid delivery system serves as a thermal management intermediary. Fluid is delivered to the surgical site to cool powered instruments and surrounding tissue, and simultaneously removes heat through convection and conduction, allowing high-speed powered instruments to be used without causing excessive heat generation or tissue damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If fluid volume at surgical site is increased, then visualization is improved, but fluid management complexity increases

Engineering Contradiction:

ImprovevisualizationVSAvoidfluid management complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

A sensor detects the fluid level at the surgical site and provides feedback to a controller. The controller adjusts the fluid delivery rate accordingly, maintaining optimal fluid volume for visualization while preventing excessive fluid accumulation. This closed-loop feedback system automates fluid management and reduces operational complexity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The fluid management system is self-regulating through feedback control. The sensor continuously monitors fluid level and automatically adjusts delivery without requiring manual intervention, allowing the system to maintain optimal visualization conditions autonomously and reducing the burden on the surgical team.

Inventive Principle:

Principle #25Self-service

4Object-generated harmful factors

If fluid turnover rate is increased, then debris removal is improved, but fluid loss increases

Engineering Contradiction:

Improvedebris removalVSAvoidfluid loss

Core Design Contradiction:

Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The sensor monitors fluid level and provides feedback to the controller. When fluid is lost through increased turnover for debris removal, the feedback system detects the level decrease and automatically increases fluid delivery to maintain optimal volume, balancing effective debris removal with fluid conservation.

Inventive Principle:

Principle #23Feedback

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

Enhances visualization and cooling at the surgical site, maintaining optimal fluid levels to improve surgical efficiency and reduce tissue damage by managing debris and heat effectively.

Implementation Method 1

cooling by controlling fluid flow rates and turnover to manage debris and heat

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

controlling fluid flow rates and turnover to manage debris

Methodology Applied

Scientific EffectFluid flow transport: Advection

Data Source

PatentUS12575817B2Systems and methods of performing spine surgery and maintaining a volume of fluid at a surgical site

Publication Date: 2026.03.17 STRYKER CORP

AI summary

Systems and methods for performing spine surgery. A retractor may be positioned within a patient to facilitate maintaining a volume of fluid at the surgical site. The retractor includes an opening capable of receiving one or more surgical instruments, for example, a cutting instrument and an endoscope. A cutting member of the cutting instrument is submerged and operated within the volume of fluid to resect tissue, for example, within the intervertebral disc space. The volume of fluid is maintained at the surgical site improves cooling of the surgical site and visualization of the surgical site via the endoscope during resection. The volume of fluid is maintained at the surgical site via the surgical system. The surgical system may include a sensor for measuring the level of fluid in the retractor, an inflow source and an outflow source in fluid communication with the retractor, and a controller controlling the surgical system.