Scoliosis Scoliosis – General

Spine Podium Presentations at POSNA Annual Meeting, April 2023

Below is my list of the top 10 Pediatric Spine podium presentations presented at the last POSNA Annual Meeting in Nashville, Tennessee (April 2023). The list is in no particular order.

My disclaimer is that I most highly value the presentations, which affect clinical decision-making and patient outcomes from surgery.

Topic #1: Anterior Vertebral Body Tethering (VBT). This surgical technique remains a topic of significant interest and hot debate, both clinically and in research, which is probably why 5 of these podium presentations were of interest to my clinical practice.


49 VBT patients (Sanders 2-4) followed up to a minimum 2-year postoperative

Evaluated the 3 apical vertebral bodies and identified a significant difference in concave vs. convex growth (2.2 mm/level vs. 0.7 mm/level), with mean 2.3 degree wedging change (or improvement). This change correlated with total body height change.

Take away message: VBT induces positive changes in the vertebral body development over the level the apical vertebral levels.


35 VBT patients followed from immediate postop to 2 year postop and excluded broken tethers.

Patients who were Risser 0-3 demonstrated no significant growth or alteration of Cobb

Patients who were Risser 4-5 did not demonstrate any significant growth documented with a 9 degree worsening of Cobb.

Take away message: Patients who are Risser 4-5 do not appear to be optimally treated with VBT (this would roughly correlate with a Sanders 6-8 score).


Compared postoperative motion in patients after VBT and Posterior Spinal Fusion (PSF), who lowest instrumented vertebra was T11 to L1. 

At 2-3 years postoperatively the reported 12 degrees of side bending motion and 13 degrees of forward flexion motion in tethered segments.

Take away message: There is a low magnitude of side bending and forward flexion motion between these two surgical approaches.  Does this amount of motion matter?


208 patients from 10 centers treated with a VBT for right main thoracic scoliosis curves.

Tether breakage reported in 36% of cases with 2-3 year follow-up. Survivorship analysis reported 50% breakage rate by 3 years postoperatively.

Take away message: The spinal deformity and vertebral bodies need to remodel by 2-3 years after surgery, prior to tether breakage, for this surgery to be effective longer term.


171 patients treated with VBT by 7 surgeons at 5 centers.

There were 156 thoracic tethers, 5 lumbar tethers, 10 double tethers. 

55 (32%) patients experienced 69 complications, and 43% of these patients receiving additional procedures.

5 patients suffered neurologic complications, including 2 patients with CSF leak.

Take away: VBT may be “minimally-invasive” procedure based on the small skin incisions, but has a very high complication rate (32%) with a 2.9% frequency of neurological (spinal cord) complications. Both of these rates are MUCH higher than those for posterior spinal fusions (PSF).

Topic #2: Posterior Spinal Fusion


64 consecutive Idiopathic Scoliosis (IS) patients followed for >10 years after surgery.

Patient reported outcome measures (SRS-24 scores) were unchanged in the follow-up period, and were better than untreated patients, except for function.

PSF to L2 and cranial had less back pain and better total SRS-24 scores than those fused L3 and caudal.

Take away message: Longer-term follow-up of PSF demonstrated good outcomes.  PSF ending at or above L2 did better than those ending at L3 or below for pain and overall function.  Therefore, we should always try to fuse shorter if possible.


31 adult patients (mean age 26 years) vs. 62 adolescents (mean age 14 years) who underwent posterior spinal fusion (PSF) for scoliosis.

Adults had less curve correction, longer operative time, more blood transfusions, longer hospital stay, longer ICU stays, higher complication rates, higher rates of pseudarthrosis (no healing) and more neurologic complications.

Take away message: It is better to do PSF for idiopathic scoliosis in the adolescent time period than in the 20s or 30s.


Evaluated cervical spine MRIs in patients with Idiopathic Scoliosis (IS). 

Cervical Degenerative Disc Disease (DDD which is arthritis) associated with increasing thoracic hypokyphosis and coronal curve severity.

Patients with cervical DDD were in an average of 11 degrees of kyphosis, those without were in 3 degrees of lordosis C2-C7

Take away message: In IS the thoracic spine has too little kyphosis than normal, which negatively affects the alignment of the neck (cervical spine).  This emphasized the need to try to restore normal amount of thoracic kyphosis at the time of surgery to optimally align the body globally and maximize cervical spine function.

Topic #3: Magnetically Controlled Growing Rods (MCGRs)


Analyzed Revisions of MCGRs.

28 patients received a 2nd set of MCGR actuators.

When compared to the first set of rods, for the 2nd set there was less length achieved (1.5 vs. 2.1 cm), less lengthening per episode (1.2 vs. 2.8 cm), less increase in T1-T12 height (2.0 cm vs. 1.5 cm). These differences can be partially explained by a shorter time the rods were in place (1st set 32 months, 2nd set 23 months).

Take away message: Despite the lower amounts of length achieved, the 2nd set of rods were in place for a shorter amount of time.  A second set of rods is reasonable if the spine stays mobile/flexible in patients with significant growth remaining, and parents/caregivers want to continue to gain height/length of the spine.

Topic #4: Api-Fix


125 patients at 17 US sites from June 2000 and August 2022 treated with the ApiFix device

9.6% of patients (n=12) had an adverse event leading to a 2nd surgery: 4 screw fixation revision, 4 broken rods, 2 converted to PSF, 2 deep SSI.

Mean thoracic curves improved from 46.5 degrees preop, to 19 degrees at last follow-up. TK increased 23.3 to 35 degrees and lumbar lordosis increased 58.5 to 64.5 degrees.

Mean lumbar curves improved 45.3 degrees preop, to 16.3 degrees at last follow-up. TK increased 23.9 degrees to 31.2 degrees, lumbar lordosis decreased 61.9 to 54.6 degrees.

Take away message: Low adverse event rate, good correction rate and low reoperation rate in this short-term/early study.  Thoracic kyphosis was preserved in thoracic surgeries but was worse for lumbar surgeries, and time will tell if this device is good/appropriate for lumbar curves.  This device will need to be removed after completion of growth.

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