Expandable Interbody Implant Restores Lumbar Lordosis

A new superalloy implant treats lordosis in adults with degenerative disc disease (DDD) at one or two contiguous levels, from L1-L2 to L5-S1.

The MiRus (Atlanta, GA, USA) IO Expandable Lumbar Interbody features a low insertion profile (4mm), a high expansion profile (18mm), and wide lordosis angle (24◦). Powered by the MoRe expansion engine, it is designed to minimize insertion height and maximize expansion height, thus making it easier for surgeons to restore lordosis and maintain sagittal balance, while reducing the challenges of insertion and related neural injury. The IO can be used in both posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) procedures.


The high strength of the MoRe superalloy allows implant designers to significantly reduce overall dimensions, so that they are thinner and less prominent. The higher ductility also results in more tolerance to deformation and reduced crack formation, increasing implant life. In addition, MoRe is highly biocompatible and osteoconductive, thus reducing allergic reactions and biofilm formation. The IO expandable implant allows for 2.5cc of biologic material to be post-packed into the inter-vertebral space.

“IO continues the MiRus philosophy of using the MoRe superalloy to create implants that objectively exceed the specifications of the existing market leading products; this delivers immense value to surgeons and patient care,” said Mahesh Krishnan, chief commercial officer of MiRus. “The IO expandable lumbar interbody will meet the significant demand of our surgeons and distribution channels, who have long anticipated a lower profile and best-in-class expandable interbody.”

MoRe is a highly pure alloy containing only two elements: Molybdenum (Mo; 52.5%) and Rhenium (Re; 47.5%). It has an extremely high density (13.52 gm/cm3) and modulus of elasticity (365 GPa), as compared to contemporary titanium-base, cobalt-base, and stainless steel implant materials. In addition, the superalloy has a lower magnetic susceptibility than commercially pure titanium, which translates into a reduced amount of magnetic resonance imaging (MRI) artifacts.

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