Operative treatment of adolescent idiopathic scoliosis with posterior pedicle screw-only constructs: minimum three-year follow-up of one hundred fourteen cases.
METHODS
Preoperative review of a prospective study, single institution, consecutive series. OBJECTIVE.: To analyze the intermediate-term follow-up of consecutive adolescent idiopathic scoliosis (AIS) patients treated with pedicle screw constructs.


BACKGROUND
There have been no reports of the intermediate-term findings in North America following posterior spinal fusion with the use of pedicle screw-only constructs.


METHODS
One hundred and fourteen consecutive patients having a minimum 3-year follow-up (mean 4.8 +/- 1.1; range, 3.0-7.3 years) with AIS were evaluated. The average age at surgery was 14.9 +/- 2.2 years. Radiographic measurements included preoperative (Preop), postoperative (PO), 2-year (2 years), and final follow-up (FFU). A chart review evaluated PFTs, Scoliosis Research Society scores, presence of thoracoplasty, Risser sign, Lenke classification, and complications.


RESULTS
The most frequent curve pattern was Lenke type 1 (45.6%), followed by type 3 (21.9%). The average main thoracic curve measured 59.2 degrees +/- 12.2 SD Preop, and corrected to 16.8 degrees +/- 9.9 PO (P < 0.0001). Sagittal thoracic alignment (T5-T12) decreased from 25.8 degrees to 15.5 degrees at FFU (P = 0.05). Nash-Moe grading for apical vertebral rotation (AVR) in the proximal thoracic curve decreased from 2.0 Preop to 1.1 at FFU (P < 0.0001), and AVR in the thoracolumbar/lumbar spine decreased from 1.6 Preop to 1.1 at FFU (P < 0.0001). Importantly, the horizontalization of the subjacent disc measured -8.3 degrees Preop which decreased to -0.9 degrees PO (P < 0.001). PFT follow-up averaged 2.4 years with a 7.1% improvement in FVC (P = 0.004) and 8.8% in FEV1 (P < 0.0001). SRS scores averaged 83.0% at latest follow-up. Age, gender, Risser sign, or complications did not have a significant effect on outcomes. There were 2 cases of adding-on, 3 late onset infections, 1 with a single pseudarthrosis, but no neurologic complications.


CONCLUSIONS
This is the largest (N = 114), consecutive series of North American patients with AIS treated with pedicle screws having a minimum of 3-year follow-up. The average curve correction was 68% for the main thoracic, 50% for the proximal thoracic, and 66% for the thoracolumbar/lumbar curve at final follow-up.
Walter Reed Army Medical Center, USA.
Ronald A
RA
Lehman
Lawrence G
LG
Lenke
Kathryn A
KA
Keeler
Yongjung J
YJ
Kim
Jacob M
JM
Buchowski
Gene
G
Cheh
Craig A
CA
Kuhns
Keith H
KH
Bridwell
D000293:Adolescent; D001863:Bone Screws; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D009656:North America; D019637:Orthopedic Procedures / Q000295:instrumentation* / Q000379:methods*; D011446:Prospective Studies; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome