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!