Cervical Sagittal Alignment in Scheuermann Disease.

STUDY

DESIGN

Retrospective evaluation of radiographs.

OBJECTIVE

The aim of this study was to assess sagittal cervical balance in patients with the two types Scheuermann disease (SD).

SUMMARY OF BACKGROUND DATA: The structural hyperkyphosis characterizing SD may be localized in the thoracic (SDT) or thoraco-lumbar (SDTL) spine segments. This may affect sagittal cervical balance.

METHODS

Seventy-one patients (41 males and 30 females), aged 16.3 ± 3.8 years with SD, were enrolled into the study. On standing lateral long-cassette radiographs, the following measurements were made: C0-2 angle, C2-7 angle (CL), C1-C2 angle, relative rotation angle (RRA)-measured at levels from C2 to C7, cervical tilt (CT), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), C0-angle, cranial offset (CO), and cranial tilt (CRT). Comparison with t test was performed with significance level P < 0.05.

RESULTS

There were 38 SDT and 33 SDTL patients. In SDT, the T1 slope was significantly greater than that in SDTL (38.1° vs. 28.9°; P = 0.0002), and consequently CL (-19.8° vs. -8.9°; P = 0.0160), CT (29.8° vs. 24.3°; P = 0.0190), and TIA (81.9° vs. 71.1°; P = 0.0022) in SDT were significantly greater as well. The difference in CL was expressed mainly in C6-C5 (-4.8° vs. -1.4°; P = 0.0146) and C5-C4 (-4.4°; vs. -1.5° P = 0.0464) segments. There were no significant differences in proximal cervical lordosis: C0-2 angle (-21.6° vs. -20.8°; P = 0.7597), C1-C2 angle (-30.8°vs. -27.5°; P = 0.1746), C3-C2 (-5.4° vs. -5.1°; P = 0.7976), and C4-C3 (3.5° vs. -1.5°; P = 0.1464) segments. There was no significant difference in cranial parameters C0-angle, CRT, and CO.

CONCLUSION

Scheuermann disease type has an influence on cervical sagittal balance. Localization of structural kyphosis affects the T1 slope as well as C2-C7 lordosis, cervical tilt, and thoracic inlet angle. Significant difference in C2-C7 lordosis in comparison to similar C0-2 lordosis demonstrates that compensation is present in subaxial cervical spine. Position of the head center of gravity is not dependent on the SD type.

LEVEL OF EVIDENCE: 4.