6. 2-Year Outcomes of Spinal Growth Tethering vs. Posterior
Spinal Fusion for Scoliosis – Flexibility vs. Reliability†
Peter O. Newton, MD; Dylan G Kluck, MD; Wataru Saito, MD, PhD; Burt Yaszay,
MD; Carrie E. Bartley, MA; Tracey P. Bastrom

17 patients who underwent anterior spinal growth tethering (ASGT) were
compared to 14 patients of similar age and comparable curve type/magnitude
and skeletal maturity who underwent posterior spinal fusion (PSF). PSF had
a greater operative time and estimated blood loss (EBL). At 2-year follow-up,
ASGT resulted in larger residual curves, but avoided PSF in the majority of
patients. The tether cohort had a higher reoperation rate. SRS-22 scores were
similar pre-op and at 2 years post-op.

ASGT will lead to similar scoliosis correction with comparable revision rates vs
PSF at 2yrs.

Retrospective cohort study
ASGT has been shown to alter spinal growth with the potential to correct
scoliosis while maintaining spine flexibility. Clinical experience with ASGT is
limited, and there are no studies comparing 2yr outcomes between ASGT and

From 2011-2013, 17 patients with thoracic major scoliosis underwent
thoracoscopic ASGT. 14 patients with PSF during a similar time period
with comparable age, curve type/magnitude and skeletal maturity were
retrospectively identified. Pre-op and 2-year post-op parameters and SRS-22
scores were analyzed.

All patients had Lenke 1 or 2 curve types and most were idiopathic. Age at
tether was 11y (range 9-14y) vs 12y (range 11-14y) for PSF (p=0.04).
Tether patients were Risser 0 and PSF patients were Risser ≤1. Pre-op Cobb
was 52±10° in tether vs 54±7° in PSF (p=0.6). Operative time in ASGT
was 194±35min, EBL 84ml (range 30-100ml) vs 278±68min, EBL 939ml
(range 300-2000ml) in PSF (p=0.001, p<0.001). ASGT had 5.8±0.5
vertebrae tethered with a 5.5±1.4 day hospital stay vs 10±1 levels fused and
a 5.5±1d stay in PSF (p<0.001, p=0.9). 2-year post-op Cobb after ASGT was
27±18° with 61% correction (range 5-173%) vs 14±8° with 73% correction
(range 38-90%) in PSF (p=0.02, p=0.3). Revision surgery was performed
in 7 tethers (4 removals due to complete/over correction, 1 lumbar added, 1
replaced, 1 PSF). PSF was indicated in 3 additional patients due to progression.
There were no revisions after PSF. SRS-22 total score at 2 years post-op was
4.7±0.2 in tether (n=5) vs 4.6±0.3 in PSF (n=12) (p=0.3).

Although most patients still had some remaining skeletal growth, ASGT resulted
in a large range of percent curve correction compared to PSF at 2 years postop.
Operative time and EBL were greater with PSF, but reoperation rates were
higher with ASGT. SRS-22 scores were similar. It is clear that the tether affects
spinal growth and, importantly, avoided fusion for most patients at 2 year