1. Correlation between Head Position and Trunk Shift in Congenital Cervicothoracic Junctional Deformities Michael Ruf, Attallah Hassanain, Lynn Letko, Tobias Pitzen Center for Spine Surgery, Orthopedics, and Traumatology, SRH Klinikum Karlsbad-Langensteinbach Karlsbad, Germany

2. Objective and Hypothesis Objective: To assess the impact of head position in patients with congenital scoliosis at the cervicothoracic junction on the overall coronal spinal balance and the effect of surgical correction. Hypothesis: Patients tend to maintain their head in a horizontal position. This however, may result in a severe impairment of the trunk balance as a mechanism of compensation.

3. Material and Methods retrospective study, 23 patients, mean age 9y8m (1y9m to 21y6m) radiological evaluation of head position and coronal balance in congenital cervicothoracic scoliosis Measurements (total spine radiograph ap in standing position): - Cobb angle main curve - Cobb angle compensatory curves - Head tilt in relation to horizon - Angle between a line from center of C7 to sacrum and CSVL (coronal deviation) 14 patients underwent surgical correction. In this patients the postoperative angles were measured as well.

4. Results

5. Preoperatively: The amount of head obliquity correlated significantly with the amount of trunk shift to the convex side of the curve (p = 0.034, r = 0.443) Results

6. Postoperatively: Again a significant correlation between head obliquity and trunk shift to the convex side of the curve (p = 0.036, r = 0.563)

7. Results Postoperatively: Surgical correction of the main curve correlated significantly with the correction of the angle C7-sacrum (p = 0.008, r = 0.672)

8. Results Correlation of head tilt and angle C7-sacrum to CSVL 5y, f.7y, m.10y, f.5y, f.11y, f.

9. Results Spontaneous correction of trunk shift following correction of the local cervicothoracic deformity 10y, f.

10. Limitations of the Study Retrospective in character No clinical outcome scales were utilized. Coronal deviation distances were not included due to technical difficulties.

11. Conclusions The position of the head in coronal plane appears to play a significant role in the overall trunk balance. Patients tend to maintain the head in a horizontal position. Failure of the cranial compensatory curve to achieve a horizontal head position in patients with cervicothoracic scoliosis was followed by a compensatory trunk shift to the convex side of the deformity.

12. Correction of the deformity with balancing of the head resulted in a spontaneous correction of the trunk shift. Position of the head should be taken into consideration when planning scoliosis correction at the cervicothoracic junction to achieve an optimal result with a balanced spine in the coronal plane. Conclusions