Tranquil™ provides the same strain as does spinal cancellous bone.

Strain determines bone quality and healing rate.

“Modulus of elasticity” doesn’t.

Let us introduce the MECHANOSTAT.

 

Strain is a measure of deformation. Bone responds to strain. Too little strain causes bone to resorb (bone loss). Too much strain causes bone to fracture. To be strong and stable, bone must be strained within safe limits.

Why have you not heard of this before?

Well, candidly, other interbody cages do not provide appropriate strain. So, others don’t talk about it.

TOO LITTLE STRAIN causes bone to resorb (bone loss).

 

A rigid cage prevents strain inside of the cage. Stable bone cannot form inside of that rigid cage, and any surrounding bone that is also shielded from strain by the rigid cage will resorb.

In this video we see that the market leading cages are too rigid to allow strain inside of them. The quail eggs experience no load when placed inside those rigid cages, even though the applied load is enough to fracture bone. The Tranquil device allows the strain to pass to the quail egg. Clearly the quail egg experienced strain inside of the Tranquil cage.

TOO MUCH STRAIN causes bone fracture, which hurts.

 

Too much strain causes endplate fracture and in turn to subsidence. The patient feels that. Nerve cells detect when there is too much strain, it is painful.

All other cages are TOO stiff to provide the strain needed for bone to grow IN IT, ON IT, or BESIDE IT.

 

Any cells inside those rigid cages get too little strain, they’re not flexed enough.

Further, any bone contacting the surface of that rigid device experiences too much strain, it is compressed too much against the surfaces of the rigid cage.

What are others doing to MASK the fact that new, stable bone is not forming in their cage?

SUPPLEMENTAL BIOLOGICS:

  • They create a mirage, a radiograph that masks the absence of new bone.
  • There isn’t new bone forming in the rigid cage, the radio-opacity of the biologic is misleading. That blob of granules does not provide stability.

You’ve likely seen an image like this.

 

Take a moment to recognize that all that pink DOES NOT provide stability. It is squishy. The few, sparse blue dots are osteoblasts, the pink is not. Ironically, their images show that their rigid devices are not forming stable bone.

Histological slice (H&E staining) of an explant 2 years postoperative. Pink demonstrates bone marrow, blue indicates trabecular bone. Bone marrow does not provide mechanical stability.

You’ve likely NOT seen an image like this.

 

Take a moment to recognize that this explant from 6 weeks post-op is full of hard bone. The bone can be palpated, and directly viewed. It is strong, stable bone. No mirage. No pink. No tricks.

How do we know the other cages are too stiff?

  1. They say so in their marketing brochures
  2. We have tested them
  3. We hold the patent on the appropriate range
  4. Compliant mechanisms – Call us to Learn more

 

Industry Buzz Words – glittering generalities, not substantive science

MODULUS OF ELASTICITY – Is a material property that cannot be changed. Titanium has a modulus of elasticity of ~ 113GPa. Isn’t it strange that so many companies suggest that they can change the modulus of elasticity of titanium?

WOLFF’S LAW – “bones will adapt to the degree of mechanical loading”. While that is true, it is not a complete description of what is needed for stable, strong bone.

Strain within safe limits is the key.

SUPPLEMENTAL BIOLOGICS – Expensive, ubiquitous band-aids that don’t change the inherent deficiencies of rigid interbody devices.

Patient-specific Rod.

 

Residual stresses from traditional rod constructs cause pain.

Residual stresses.

 

Residual stresses from traditional rod constructs cause pain.

Residual stresses.

 

Residual stresses from traditional rod constructs cause pain, and make things break.

Simple Revision.

 

Avoid exposing the old construct, instead just attach to the end.

Simple Revision.

 

Avoid exposing the old construct, instead just attach to the end.