Sunday, September 29, 2013

16 yo Justin with Grade 4 L5-S1 Spondylolisthesis pseudarthrosis with flatback syndrome and 45 degree anterior tilt goes home today!

At Hey Clinic, we see many straightforward adolescent, early onset and congenital scoliosis patients, as well as  adult patients who had adolescent and/or childhood scoliosis now with curve progression and pain.  We also see many patients for second and third opinions for surgery, revision surgery and scoliosis bracing.  Some of the revision surgery consults we get can be quite challenging, and actually require me to do further research, and even touch base with some of my Scoliosis Research Society (SRS.ORG) colleagues around the world, as well as combing the literature to find the best, least invasive solution.  Some cases also require me to really use my engineering training and experience, carefully examining the loads, vectors, and translation and re-angulation forces, as well as rod/screw stresses to figure things out.

Justin's case definitely fit into this last category.  Justin had a high grade L5S1 spondylolisthesis, probably Grade 3, which means that his L5 vertebra was slipped between half and 3/4 forward on the sacrum.  He had an instrumentation and fusion done elsewhere at age 13 from L4-S1, fused in situ, meaning that they just fixed it in the position he was in.  Unfortunately, the hardware loosened and one screw broke, and the L5 vertebra slipped even further forward, and then started to fall off the front of the sacrum, tilting forward about 45 degrees.  One of the remaining sacral screws was poking out, tenting the skin on the left side.  Justin had quite a bit of pain, and really couldn't stand up very well, having to keep his knees bent with "flat back syndrome" posture.  In some sense you could say that Justin's top half of his body was not very well connected to the bottom.  Big problem.

There are several ways to approach this problem:  one way would be to go anteriorly and posteriorly (front and back), and jack up the L5 vertebra back on top of S1, with an interbody spacer.  That's pretty invasive though, and runs small risk of retrograde ejaculation, which could make Justin sterile.  Another way to do it is through a posterior approach, to try to pull the L5 vertebra back into position and tilt it back up where it belongs.  The problem with this approach is that it can cause a stretch injury to the L5 nerve roots.  To help prevent the L5 nerve root problem, you can do something called a "dome osteotomy", where you cut off the rounded off top of the sacrum, shortening it a bit, and give the sacrum a flat surface so the L5 vertebra can sit on top of it.  This shortening helps prevent the stretch on the nerve roots.

After much preop research, planning and discussion, including with several of my SRS colleagues at the SRS meeting last week, including Dr. John Emans and Tim Hresko from Boston Children's Hospital and Dr. Sig Berven from UCSF, a final surgical plan was developed.  I found several good articles out there through PubMed, and this article from Kan Min et al in the European Spine Journal had a very good discussion of the surgical technique for the decompression and reduction.

His surgery went very well this past Thursday.   I used a special operating room bed and 3D Navigation to help with the anatomy, and new hardware placement and correction.  I was able to get the broken screw out of the sacrum using special screw removal set and the 3D nav.  The L5 nerve roots were carefully identified and decompressed, including removing the disc bulges below both nerve roots, and ensuring nerve roots were freed up.  Then, I completed the L5S1 discectomy, identifying the large "dome" of bone of top of sacrum, rounded off by the spondylolisthesis over time.  Using the bur and osteotomes, coming at it from both sides, gently retracting the nerve root sac, I was able to remove the "dome", and create a shorter, flat surface.  I then used 2 very strong iliac wing screws combined with redirected sacral screws and carefully contoured titanium rods to form the foundation of the construct.  I then used my special "Pursuader" system to very slowly and gently pull L4 and L5 backward and into alignment, doing a few twists of the "corkscrew" tops then waiting, checking the evoked potential monitoring, and checking the L5 nerve roots bilaterally for tension and pressure.   "Cool" was the word at that point.  The L5 vertebra came beautifully back into position.  Very Cool.   Slowly, and steadily the L5 vertebral body, and Justin's entire top half of his body slid back into proper position, at which point I was able to lock the caps into position, put in the bone graft and close!!   No evoked potential changes and we were able to get a great correction.  This whole process took about 6 and a half hours!! Whew.  Aftwerward, Justin's folks were definitely thankful, and so was Justin as you can see below.  He has done wonderfully postop, standing up straight, and with his nerves all working fine.

So, Justin went home today looking and feeling well.  Many thanks to everyone who helped make his surgery so successful, including my spine colleagues, and even "Nurse Kelly" who came in on her day off to help.

Dr. Lloyd Hey
Hey Clinic for Scoliosis and Spine Surgery

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