M6-L Overview

The M6-L artificial lumbar disc offers an innovative option compared to other artificial lumbar disc replacement because of its unique design, which is based on the qualities of the natural disc.

The M6-L is the only artificial disc that incorporates an artificial nucleus (made from polycarbonate urethane) and a woven fiber annulus (made from polyethylene). The M6-L artificial nucleus and annulus are designed to provide the same physiologic motion characteristics of a natural disc. Extensive biomechanical testing with the M6-L artificial lumbar disc has demonstrated equivalent Quality of Motion compared to the healthy disc.

Together, the M6-L’s artificial nucleus and annulus provide compressive capabilities and a controlled range of natural motion in all 6 degrees of freedom. This “natural” motion is designed to provide the freedom to move your back naturally.

The M6-L has two titanium outer plates with keels for anchoring the disc into the bone of the vertebral body. These outer plates are coated with a titanium plasma spray that promotes bone growth into the metal plates, providing long-term fixation and stability of the disc in the bone.

M6-L Disc Cutout

M6-LArtificial Disc Components

Artificial Nucleus Artificial Nucleus

  • Viscoelastic polymer designed to simulate native nucleus
  • Allows physiologic axial compression
  • Retained between endplates by fiber annulus matrix
  • Designed to facilitate physiologic Center of Rotation (COR)
Artificial Annulus Artificial Annulus

  • Ultra High Molecular Weight Polyethylene (UHMWPE) fiber material
  • Intended to simulate native annulus and its performance characteristics
  • Designed to provide controlled motion in all planes & axes of rotation
  • Robust fiber matrix with multiple fiber layers similar to native annulus
Sheath Sheath

  • Viscoelastic polymer designed to minimize tissue in-growth and debris migration
  • Flexible design allows for full range of motion
Fixation Fixation

  • Titanium endplates with low-profi¬le keel design provides for optimal acute and long-term ¬fixation
  • Titanium Plasma Spray (TPS) coated endplates provide for osseointegration

M6-LQuality of Motion

Quality of Motion assesses how well the motion of an implanted functional spine unit approximates the motion of a healthy one over the entire range of motion, not just its endpoints. Through biomechanical testing, a load vs. angular displacement curve (“kinematic signature”) is generated that allows assessment of the Quality of Motion parameters.

Biomechanical testing with the M6-L artificial lumbar disc has demonstrated equivalent Quality of Motion compared to the healthy disc. The innovative artificial fiber annulus and nucleus construct of the M6-L is the critical component in replicating this physiologic motion, as it is designed to provide the necessary restraint and control needed throughout the spine’s natural range of motion.

The “kinematic signatures” of the intact disc (red) and M6-L lumbar disc (blue) are nearly identical. The M6-L lumbar disc maintained total ROM, vs. Intact , at 400N [9.4°±2.2° vs. 8.8°±1.1°, p=0.56], and at 800N [9.5°±2.1° vs. 8.4°±1.2°, p=0.32], with excellent Quality of Motion.

Patwardhan et al. Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, Illinois, USA.