Assisted Leg Holding Device For Medical ProceduresBy:Jennifer BrunoKatherine EtterGehendra Kunwar

Team 1

Funded by:Rehabilitation Education Research Center

Client Contact Information:Dr. John D. Enderle

Overview1. Introduction

A. PurposeB. RequirementsC. Research/Work Done By Others

2. Final Design1. Subunits2. Future additions

3. Budget 4. Highlighted Features5. Conclusion/Acknowledgements/Questions

Introduction In the United States, about 51.2 million people

are disabled Leg holding devices are required for many

medical procedures Important for patients to have a positive experience

as to keep up with preventative screenings and to reduce anxiety

Problems with traditional leg-holding devices. Lack of adjustability, patients outside the “normal”

range Practitioners have difficulty positioning patients who

are overweight or have severe disabilities

The assisted leg holding device employs anti-gravity techniques to balance each patient’s

weight, so that the patient’s legs can be positioned effortlessly by a practitioner.

Purpose

RequirementsComfortableVersatile (can be used by a wide variety of

patients)Adhere to medical standardsLow costCompact and easy to relocateEasy to sterilizeNot imposing or intimidatingDurable and reliable

Product Research

Allen YellofinTM Lithotomy Stirrups intra-operative re-

positing of patients mimics natural motion

of the hip prevents excessive

pressure on the calf Accommodates patients

up to 500 lbs

Patents 2714541

approved in August, 1955 One of the earliest patents found pertaining to this subject, stirrup

only supports the patient’s foot extremely compact and can be easily stored to maximize space

within the operating room 4809687

approved in September 1989 cushioned shell that supports a patient’s foot and lower leg accommodates for patients with joint or muscle disease

5802641 approved in September 1998 can be adjusted to support a patient against gravity uses a motorized system

A Useful Paper: “A Simple Technique to Passively Gravity-Balance Articulated Mechanisms”

Link Free Body Diagram Total Potential Energy Must Equal Zero!

0*)2/1(cos***

:

*)2/1(

:

cos***

:

2

2

nnnn

nn

nnn

xKlgmTPE

EnergyPotentialTotal

xKSPE

EnergyPotentialSpring

lgmGPE

EnergyPotentialnalGravitatio

Substituting and solving…

Spring Constant K=(m*g*l)/(a*b)

Patients benefiting from this device:

Phylis rheumatoid arthritis, joint stiffness, pain Jerry Parkinson’s disease, tremor, rigidity, and decreased range of motion Jamie T11 spinal cord injury Betty limited and asymmetrical lower extremity range of motion, limited strength in her right leg, pain caused by her hip Violet short stature Paul two below-the-knee amputations

Final Design

Assisted Leg-Holding Device

Gravity-Balancing Mechanism                                                 

SPRING

WELDED I-HOOK

CORDLINEAR SLIDE

MOTOR

Motor – Stepper Motor

MDrive23 Plus Microstepping

PIC Microprocessor

PIC16F877

Foot and Thigh Supports

Attachment to Table

Front View Top View

Aluminum Support

Pivot and Lock

Device

Future Additions

Scale with Bluetooth capabilities to transmit patient weight to PIC for automatic adjustment

Automatic braking system to lock the device in place during a medical procedure

Highlighted Features

Anti-gravity technology allows the practitioner to adjust the position of a patient’s leg in a “weightless” environment

Device is adjustable for patients weighing up to 300 pounds Device is adjustable for a patient leg range of 20 inches to 44 inches Device is adjustable for a variety of leg positions from fully bent to fully

extended Device is adjustable for a variety of leg positions from close together to

widely spread Device can be removed from table and stored when not in use Medical drapings allow the device to be sterilized easily between

procedures Adjustable, Velcro-secured foot and knee supports allow for extra comfort

and support during procedures and can accommodate amputees

Budget

Conclusion

The proposed design

- provides full leg support to disabled patients

-offers an easy solution for practitioners who are unable to comfortably adjust patients

- allows a wide range of adjustability to ensure patient comfort and procedure integrity

Acknowledgements

RERC-AMI Funding

Dr. John D. Enderle

Dave Price

Rich and Serge

Dave Kaputa

References

www.census.gov/PressRelease/www/releases/archives/facts_for_features_special_editions/010102.html

T. Rahman, R. Ramanathan, R. Seliktar, and W. Harwin, "A Simple Technique to Passively Gravity-Balance Articulated Mechanisms," J Mech. Des. vol. 117, pp. 655-658, 1995.

Questions??

Thank you for your attention!