Progrression of 35-50 Degree Curves with 20 Year Follow-Up

[LindaRacine]

From the SRS meeting:

74. Minimum 20-Year Radiographic Outcomes for Treatment of Adolescent
Idiopathic Scoliosis: Preliminary Results from a Novel Cohort of US Patients
A. Noelle Larson, MD; David W. Polly, MD; William J. Shaughnessy, MD; Michael
J. Yaszemski, MD, PhD
USA

Summary: AIS patients with 35-50° curves treated nonoperatively in childhood
had progression in adulthood at a slow rate (mean 0.5 degree per year for
thoracic curves). However, some individuals had rapid progression and others had
no progression. Further work is required to determine why this occurs.

Introduction: There is limited recent data regarding the long-term outcomes
of scoliosis treatment. This study evaluates the minimum 20-year outcomes
following treatment of adolescent idiopathic scoliosis with bracing, surgery, or
observation in a novel cohort of US patients.

Methods: All patients had radiographs from adolescence at skeletal maturity
(Risser 4 or 5) and were contacted for current radiographs, pulmonary function
tests, and physical exam. Patients had at least a 35° idiopathic scoliosis
curve magnitude during adolescence. Childhood treatment included bracing/
observation (19) and surgery (12, either Harrington or CD instrumentation).
Results: Thirty-one patients had radiographs/physical exam at a minimum of
20-years following treatment. Mean time to follow-up was 28.1 years (range,
20-36). Mean age at childhood radiographs was 16.4 (range, 14 - 20). Mean
age at follow-up was 44.1 years (range, 36-54). Of the 19 nonoperative
patients, only 3 did not progress (Figure). For the remaining 16 patients,
thoracic curves progressed a mean of 0.54° per year (range, 0.2 - 1.3), and
lumbar curves progressed 0.37° (range, 0.2-0.9). Larger curves more frequently
progressed (Rsquare 0.61, 0.49). Three patients in the nonoperative group
underwent spine surgery in adulthood for lumbar discectomy (1), anterior
cervical fusion (1), and lumbar fusion (1) below the level of the deformity. Of
the 12 operative patients, 3 (25%) had additional procedures in adulthood,
including implant removal (2) and distal extension of the fusion (1). Despite
fusion, 8/12 surgical patients had mild curve progression, at a rate of 0.3° per
year.

Conclusion: Idiopathic scoliosis curves between 35-50° continue to progress
during adulthood, but this varies by individual. Thoracic curves progress more
quickly than lumbar. Elucidation of the factors which govern progression in
adulthood may help guide childhood treatment recommendations.
Curve progression for each patient. The solid line represents no change. The
broken lines indicate +/- 5 degrees.

SRS 74.jpg

[jrnyc]

i am surprised that thoracic curves progress faster than
lumbar curves...
to me, the lumbar area seems to have more stressors and
less support...
that is just a subjective observation....

is there any known reason for different rate of progression
of thoracic vs. lumbar curves....????

jess

[LindaRacine]

I'm guessing, but I bet if they look at the same patients again in another 20 years, there will be a big switch in those numbers.

[rohrer01]

Jess,
Just a guess, but since the thoracic vertebrae are less flexible, maybe the flexibility of the lumbar keeps it straighter. It's able to move around, whereas the thoracic has no means of exercise other than breathing and very little flexibility as compared to the lumbar.

In short, maybe flexibility is a good thing!

[cello_mom]

Makes me glad we did the surgery at 15 yrs for a 60 degree curve. At 35 years old it would potentially have been closer to 70-80 degrees.

[rohrer01]

My original doctors predicted when I was 16 years old that I would "need" surgery in my early to mid 40's for a curve >40^o.
Although, it is official that I did reach over 40^o and I was in my early 40's when my surgeon here diagnosed me as such, Dr. Perra at TCSP diagnosed me at 41^o curve at the age of 29. His measurements now would probably put me over 50^o as he measures curves less conservatively while other doctors measure curves more conservatively. Curve measurements aren't an exact science. Degrees of error are in reality degrees of subjectivity. My doctors at 16 were more conservative than the chiropractor that originally measured me at 39^o. The ones at Phoenix Children's Hospital were measuring at 37^o both standing and lying down (I remember that now. I got both each time. Maybe the concussion brought back some long term memory while it shot other memories to pieces!?) So according to them, they were spot on! Quite intriguing to me, really.

But that's a super stiff curve is you ask me!