LM 120 Story

My name is Lawrence Guillen, and I invented the FDA Class I Medical Device, the LM 120 with HyperX. I graduated in 2003 from the Physical Therapy Assistants’ program at San Juan College, Farmington, New Mexico. In 2005, I joined the staff at a physical therapy clinic in Aztec, New Mexico. My job involved mostly working with senior citizens who had recently had total knee replacement (TKR) surgery and were in the clinic for rehab. I soon became frustrated as I watched them tense in anticipation of pain while undergoing manual therapy. I knew there had to be a way to mechanically move the lower limbs to achieve the desired results of flexion and extension and to place the client in control of his or her pain. This is how the story developed over time.

Prototype Number One: The “crank”

This model consisted of an oblong plastic plank with a center trough fitted with a stainless steel insert. I used a crank with ratchet from Ace Hardware to which I rigged ropes to pull the leg. The client sat at the head of the plank and would wind/unwind the ropes to move the leg, which was strapped to a thin plastic square down the length of the trough. I took this model to a patent attorney in Albuquerque. Dennis Armijo advised me that this version was too crude and wasn’t mechanized.

Prototype Number Two: The “Easy Flex”

To the above apparatus, I added an actuator with a worm drive, powered by a motor. The motor generated enough torque to move a seven pound foot pad but was as loud as a lawn mower! The client controlled the motor using a handle I sawed off from an electric drill.

Prototype Number Three: The Linear Motion Therapy Device, the LMTD

The device had been upgraded to include a corset in which the patient’s hips were firmly stabilized to prevent side-to-side and up-and-down movement; a thigh support and a foot pedal mechanism that allowed the limb to be mechanically flexed and extended by the worm-driven actuator. The direction of force was from hip-to-knee-to-foot, with the patient using a hand-held, electronic control mechanism. This was the device and documentation that Dennis submitted to the US Patent Office.   In December 2014, I was granted utility patent number US9205015B2. Meeting in Dennis’ office, he showed me a shelf behind his desk of patented inventions that had never gone any further. His advice to be persistent has proven to be invaluable.

Prototype Number Four: The “Improved LMTD”

The Small Business Development Center at San Juan College introduced me and my manager, Linda Parks, to the New Mexico Small Business Assistance Program. My company, Linear Motion 120, was awarded two $20,000 consultation grants to work with Charles Brusseau of Sandia National Laboratories to re-engineer the apparatus.   For marketing purposes, I needed the device to be less heavy and to be more esthetically pleasing. New concepts were discussed and debated over the course of one year, but no working model was achieved.

Prototype Number Five: The LM 120 with HyperX

We next interviewed two engineering firms in Albuquerque, but settled on a machinist who advertised his expertise in prototyping in the Yellow Pages. Through the collaborative R & D process, the machinist changed the seating to a cushioned, aluminum rectangle with receptacles embedded in the backrest to hold a waist belt for hip stabilization. The seating platform with projecting stainless steel bar connected to an aluminum rectangular box designed to support the leg and contain the actuator and the electronics. The actuator box could be moved via the bar to accommodate either a right or left leg. The foot rest traveled within a slot in the middle of the box.

In addition to flexion, extension was enhanced through a cam-and-loop arrangement to depress the thigh. A wireless, hand-held tablet controlled the electronics. The device name was shortened, and the HyperX function added to the name because of its potential benefits. Although significant changes were made to the device, the machinist was ultimately not disciplined enough to provide us with a Bill of Materials (BOM) nor capable of producing CAD drawings as promised.

Prototype Number Six: The LM 120 with HyperX, a Medical Device

In the course of our work with the machinist, Charles Brusseau had retired and opened his own design business. Ultimately, he was recruited to modify the backrest of the seating platform to be more adjustable, to incorporate three-D printing for 18 component parts which brought the two components to slightly over 30 pounds, to refine HyperX (the extension mechanism) and to engineer a more ergonomic foot rest.

Charles’ reverse engineering resulted in a FDA-worthy BOM and CAD drawings. We submitted this documentation to the FDA in April 2023 for scrutiny under the 513 (g) program. In November 2023, the FDA designated the LM 120 with HyperX to be a Class I Medical Device. The design modifications have been protected under a provisional patent. Full Spectrum Solutions, an electrical engineering firm in Edgewood, has produced a state-of-the-art, accurate and safe electronic and software package. We are now poised to partner with savvy investors to manufacture and market the device.