Non-fusion technologies for the treatment of scoliosis in
the growing patient, has garnered increasing interest from patients and
surgeons over the last 10 years. The
advantages have been touted as being a minimally invasive procedure, rapid
postoperative recovery, faster resumption of normal activities, less
postoperative pain and preservation of more spine motion, when compared to
The first system used for Anterior Vertebral Body Tethering
(AVBT) was the Zimmer Biomet Dynesys system.
This system was originally designed for use in adult patients and in the
posterior spine, and was used in an off-label/unlabeled manner in the anterior
spine in the growing patient. This was
the precursor system to their current system which achieve FDA approval for use
on the anterior spine in growing patients in August 2019. The pluses and minuses of this surgical
treatment has been previously posted on this blog, so I will refer those
interested to scroll back through the blog to those posts (May 2017, November
2017, January 2018 x 2, and February 2018).
Another growth modulation system, the ApiFix Minimally
Invasive Deformity Correction (MID-C) system, was also approved in August
2019. Unlike the AVBT system, there was
no similar device which could be used in the U.S. prior to the FDA approval. Most of the clinical experience with this
system, which was used for FDA approval, was from outside the U.S. This means there is much less clinical
experience with this device, when compared to AVBT, in the U.S.
As opposed to the AVBT system, which is placed on the front
of the spine and compresses the convex side of the curve, the MID-C system is placed
posteriorly and distracts on the convex side of the curve.
As you see above, there are two pedicle screws on the top
and one at the bottom. The mechanism is
in the middle, which ratchets apart with bending.
At present the current indications for the use of the ApiFix
(thoracic) or 5 (lumbar) curve patterns
degrees coronal deformity
</= 30 degrees
< 55 degrees
The surgical technique looks similar to a posterior spinal
fusion, due its skin incision. However there
is not as much dissection or blood loss, so recovery is faster
At present the MID-C and AVBT have similar indications
To learn more about ApiFix MID-C: