Predictive factors for a distal adjacent disorder with L3  as the lowest instrumented vertebra in Lenke 5C patients.
OBJECTIVE
To investigate what type of Lenke 5C patient benefits most from a fusion to L3 as the LIV.


METHODS
The subjects were 16 patients who underwent fusion surgery to L3 as the lowest instrumented vertebra (LIV), and who were then observed for a minimum of 2 years postoperatively. We considered an unsatisfactory radiologic outcome for the distal adjacent curve (DAD) to be an L3 or L4 tilt angle less than 10° or L3/4 disc wedging less than 10°. Patients were divided into 2 groups based on the radiologic outcome of the distal curve: the distal adjacent disorder+ (DAD+) and the distal adjacent disorder-(DAD-). We compared global balance, Cobb angles (thoracic and lumbar), L3 and L4 tilt angles and L3/4/5 disc angles between the 2 groups on preoperative, postoperative and final radiographs.


RESULTS
Seven patients (43.8 %) met the criteria for the DAD+ group. On preoperative radiographs, there was a significant difference in the L3/4 disc angle: the DAD+ group opened to the preoperative convex side (-2.1° ± 3.0°) and the DAD- group opened to the preoperative concave side (4.7° ± 5.1°). The standing L3- and L4-CSVL and the L4-CSVL under traction were significantly different.


CONCLUSIONS
In Lenke 5C patients who underwent fusion surgery to L3 as the LIV, preoperative LIV (L3), LIV + 1 (L4) translation and L3/4 disc angle on standing, plus LIV + 1 translation under traction were very important parameters correlating with postoperative global coronal balance.
Kei
K
Ando
Shiro
S
Imagama
Zenya
Z
Ito
Kazuyoshi
K
Kobayashi
Tetsuro
T
Hida
Kenyu
K
Ito
Akito
A
Tsushima
Yoshimoto
Y
Ishikawa
Akiyuki
A
Matsumoto
Yoshihiro
Y
Nishida
Naoki
N
Ishiguro
D000293:Adolescent; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery; D008297:Male; D012189:Retrospective Studies; D012600:Scoliosis / Q000473:pathology / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D013904:Thoracic Vertebrae / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult