Project TitleDiaphragm-Based Hybrid Prosthetic Vacuum Pump for Transfemoral Amputees
Track Code2013-184 and 2011-089
Short Description

Unique prosthetic solutions that include multiple designs of hybrid (mechanical and electrical) vacuum pumps. #medicaldevice #prosthetics #rehabilitation 


Northwestern scientists have developed a unique suspension system for prosthetic devices that include mechanical and electrical pumps. The mechanical aspect of these designs use either a bladder or a diaphragm to create negative pressure. Both designs have a lower build height than commercially available mechanical pumps, making them suitable for use in-line with sockets, especially in transfemoral (above-knee) prostheses. Working in concert with an electrical pump, both hybrid pump designs offer the quietness of mechanical actuation, with the speed of electrical actuation. Various suspension systems have been developed for coupling a prosthetic limb to a residual limb. Our earlier bladder-based hybrid pump design generated a clinically acceptable level of vacuum but was less robust to out-of-plane movements during compression than the subsequent diaphragm-based design. While both designs provide for a lower build height than existing mechanical pumps, the space savings are greater with the diaphragm-based design. 

Tagsbiomedical, MEDICAL DEVICE: prosthetics/rehabilitation
Posted DateApr 19, 2017 4:54 PM


Stefania Fatone*

Matthew Major

Ryan Caldwell

Andrew Hansen


• A mechanism to hold the prosthetic socket onto the residual limb for lower-limb amputees


• Hybrid function: Unobtrusive, quiet operation and minimal need for battery recharging  

• Small build height for transfemoral amputees (suitable for placement between the prosthetic knee and socket) 

• Improvement upon the size and function of existing prosthetic vacuum pumps  

• Minimal displacement/excursion required by diaphragm to function and hence minimizes range-of-motion added to prosthesis 

• Optimization of the size and function of existing prosthetic vacuum pumps 


Major M, Calldwell R, Fatone S (2015).  Evaluation of a Prototype Hybrid Vacuum Pump to Provide Vacuum-Assisted Suspension for Above-Knee Prostheses.  J Med Device 9(4):0445041-445044

IP Status

NU 2013-184: Provisional application 62/214,560 

NU 2011-089: Issued US Patent No. 9,066,822; Pending 14/730,806 & 14/730,816 

Contact Information

Dimitra Georganopoulou, PhD 

Innovation & Commercialization Officer 

(p) 847.467.3095