The evolution of sagittal segmental alignment of the

The evolution of sagittal segmental alignment of the spine during growth Muharrem Yazici, MD Hacettepe University, Ankara, Turkey Hacettepe Orthopaedics Spine Unit

Background q Planning spine of the 3 D reconstruction of the q Normative data about the sagittal plane q Segmental sagittal plane analysis q Many studies for adults q Inadequate data on children

Questions q Whether the pediatric spine is a miniature of adults’ in terms of sagittal plane alignment? q If not, do segmental alignment of the vertebrae change with growth?

Objective q To describe the normative data of the sagittal plane on pediatric age population q To document the evolution of sagittal alignment with growth

Materials&Methods q 151 children (72 girls, 79 boys) q No musculoskeletal abnormality q Spine deformity q Limb length inequality q Hip or knee contracture No previous spinal surgery q Age, 3 to 15 q q Minimum of 10 children in each q At least 4 of them from one sex age group

Materials&Methods q Standart radiograms q Same technician q Left side at the cassette side q Tube-cassette distance, 150 cm q 36 -inch standing lateral X-ray with the arms flexed at 30°

Variables q q q Segmental angulations from T 1 -2 to L 5 S 1 Global kyphosis (T 1 -12) and lordosis (L 1 -S 1) Apices T 1 and L 1 offsets Location of thoracic and lumbar apices Spinopelvic alignment measurements q q Alpha and Beta angles Sagittal vertebral axis (SVA) Sacropelvic translation (SPT) Sacral translation(HA-S 1)

Statistical analysis q Grouping in terms of ages Group I (3 to 6 years of age) q Group II (7 to 9) q Group III (10 to 12) q Group IV (13 to 15) q q Intra-observer error q Re-measurement of 20 radiograms

Results q Intraobserver error Segmental measurements 2. 4 o± 2. 2 q Milimetric measurements 2. 6 mm± 2. 9 q Upper thoracic area is problematic q q Difficulty in defining the upper thoracic vertebral endplates q HA-S 1 and alpha angle q 94 X-rays only q Quality q <5 years of age q Lack of femoral head ossification center

Results q Pediatric vs. adults q Greater thoracic kyphosis q Smaller lumbar lordosis q Especially upper 3 segments q More kyphotic thoracolumbar q 3. 6 o-9. 8 o q More forward sagittal vertical axis q Lower sacral inclination hypolordotic region

Results/ Significant difference among Groups q Junctions Segmental angulations of T 1 -2 (p=0. 015) q T 10 -L 2 (p=0. 014) q L 4 -S 1 (p=0. 001) q Global kyphosis angle (p=0. 005) q Global lordosis angle (p=0. 000) q Thoracic apex (p=0. 007) q T 1 offset (p=0. 000) q SVA (p=0. 004) q Beta angle (p=0. 000) q

Results Sagittal spinal alignment is changing as child grows q Significant difference especially at cervicothoracic, thoracolumbar, and lumbosacral junctions q

Results Lordosis q With age q Total Kyphosis thoracic kyphosis, and total lumbar lordosis particularly due to lower 2 motion segments, were found to be increased q Not linear q Group III/adolescent growth spurt q Anterior column growth exceeds posterior q Thoracic apex moved upwards

Results The position of the sacrum (inclination and translation), and spatial orientationchanges with growth q Older children to stand with a more negative SVA q Trend of alpha angle was disturbed because of Group 3 q

Drawbacks q Not regular randomization Same technician q Random selection q q No bias q Only ten subjects in each group Statistical power? q Regrouping q q Cross-sectional design q Prospective study? ?

Conclusion Not a smaller model q Alignment dynamically changes q Young patients who require spinal instrumentation!!! q Negate the adverse effects of sagittal malalignment q Risk for abnormal loading q q Adjacent spine segments q Hip, knee

DDH and knee study

Early spine fusion

Early spine fusion

Conclusion q Whether sagittal alignment should be restored according to the normative data for the child’s age or to the normative data for the adulthood? q Adult data q Abnormal loading q Pediatric data q Adult posture can never be attained