Three-dimensional reconstruction using stereoradiography for evaluating adult spinal deformity: a reproducibility study.
In addition to the sagittal alignment, impact of transverse plane parameters (TPP) and rotatory subluxation on patients reported outcomes were highlighted. One of the hypotheses for genesis of degenerative scoliosis is disc degeneration with increased axial vertebral (AVR) and intervertebral rotation (AIR). Therefore, TPP analysis at early stage of the scoliosis seems of particular interest. This study aims at assessing reliability of tridimensional (3D) reconstructions of adult spinal deformity (ASD) patients.



Thirty ASD patients underwent biplanar radiographs and were divided into two groups (Cobb angle >30° or <30°). Spinal parameters and TPP (apical AVR, AIR of upper and lower level of main curve) were measured. Four operators performed 3D reconstructions twice. Intra and inter-observer reliabilities were analyzed using ISO standard 5725-2, to quantify the global standard deviation of reproducibility (SR).



Mean Cobb angle was 31°, mean age 55 years (70% of female). Mean values of apical AVR, upper and lower level AIR were, respectively, 16° ± 15°, 6° ± 6° and 5° ± 5°. Spinopelvic parameters SRwere below 4.5°. For Cobb angle <30°, SRwas 7.8°, 9.6°, 4.5° and 4.9°, respectively, for AVR apex, torsion index, upper and lower AIR. Reliability was worse in the group of patients with Cobb angle above 30°.



3D analysis was reliable for Cobb and sagittal parameters. 3D analysis for TPP was reproducible when Cobb is below 30°. However, uncertainty is larger for Cobb above 30°. Nevertheless, 3D reconstructions could help surgeons to anticipate onset of rotatory subluxation while assessing axial rotation evolution for small deformity and choose best delay for surgical treatment.
Department of Orthopaedic Surgery, Hopital Européen Georges Pompidou, APHP, Paris V University, 20 rue Leblanc, 75015, Paris, France. emmanuelle.ferrero@aphp.fr.|Laboratoire de biomécanique Georges Charpak, Ecole nationale supérieure des arts et métiers, 75013, Paris, France. emmanuelle.ferrero@aphp.fr.
Emmanuelle
E
Ferrero
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Renaud
R
Lafage
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Shaleen
S
Vira
Laboratoire de biomécanique Georges Charpak, Ecole nationale supérieure des arts et métiers, 75013, Paris, France.
Pierre-Yves
PY
Rohan
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Jonathan
J
Oren
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Edward
E
Delsole
Department of Orthopaedic Surgery, Hopital Européen Georges Pompidou, APHP, Paris V University, 20 rue Leblanc, 75015, Paris, France.
Pierre
P
Guigui
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Frank
F
Schwab
Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Virginie
V
Lafage
Laboratoire de biomécanique Georges Charpak, Ecole nationale supérieure des arts et métiers, 75013, Paris, France.
Wafa
W
Skalli
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D059869:Radiostereometric Analysis / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging*; D013131:Spine / Q000000981:diagnostic imaging*
Adult spinal deformity; ISO standard; Reproducibility; Transverse plane parameters; Tridimensional analysis