Spinopelvic sagittal compensation in adult cervical deformity

OBJECTIVE The objective of this study was to evaluate spinopelvic sagittal alignment and spinal compensatory changes in adult cervical kyphotic deformity.METHODS A database composed of 13 US spine centers was retrospectively reviewed for adult patients who under-went cervical reconstruction with radiographic evidence of cervical kyphotic deformity: C2-7 sagittal vertical axis > 4 cm, chin-brow vertical angle > 25 & DEG;, or cervical kyphosis (T1 slope [T1S] cervical lordosis [CL] > 15 & DEG;) (n = 129). Sagittal parameters were evaluated preoperatively and in the early postoperative window (6 weeks to 6 months postoperatively) and compared with asymptomatic control patients. Adult cervical deformity patients were further stratified by degree of cervical kyphosis (severe kyphosis, C2-T3 Cobb angle & LE; -30 & DEG;; moderate kyphosis, & LE; 0 & DEG;; and minimal kyphosis, > 0 & DEG;) and severity of sagittal malalignment (severe malalignment, sagittal vertical axis T3-S1 & LE; -60 mm; moderate malalign- ment, & LE; 20 mm; and minimal malalignment > 20 mm).RESULTS Compared with asymptomatic control patients, cervical deformity was associated with increased C0-2 lordosis (32.9 & DEG; vs 23.6 & DEG;), T1S (33.5 & DEG; vs 28.0 & DEG;), thoracolumbar junction kyphosis (T10-L2 Cobb angle -7.0 & DEG; vs -1.7 & DEG;), and pelvic tilt (PT) (19.7 & DEG; vs 15.9 & DEG;) (p < 0.01). Cervicothoracic kyphosis was correlated with C0-2 lordosis (R = -0.57, p < 0.01) and lumbar lordosis (LL) (R = -0.20, p = 0.03). Cervical reconstruction resulted in decreased C0-2 lordosis, increased T1S, and increased thoracic and thoracolumbar junction kyphosis (p < 0.01). Patients with severe cervical kyphosis (n = 34) had greater C0-2 lordosis (p < 0.01) and postoperative reduction of C0-2 lordosis (p = 0.02) but no difference in PT. Severe cervical kyphosis was also associated with a greater increase in thoracic and thoracolumbar junction kyphosis postoperatively (p = 0.01). Patients with severe sagittal malalignment (n = 52) had decreased PT (p = 0.01) and increased LL (p < 0.01), as well as a greater postoperative reduction in LL (p < 0.01).CONCLUSIONS Adult cervical deformity is associated with upper cervical hyperlordotic compensation and thoracic hypokyphosis. In the setting of increased kyphotic deformity and sagittal malalignment, thoracolumbar junction kyphosis and lumbar hyperlordosis develop to restore normal center of gravity. There was no consistent compensatory pelvic retroversion or anteversion among the adult cervical deformity patients in this cohort.

Automated summary

The study aimed to evaluate spinopelvic sagittal alignment and spinal compensatory changes in adult cervical kyphotic deformity. A database of 129 adult patients undergoing cervical reconstruction was reviewed and compared with asymptomatic control patients. The results showed that cervical deformity was associated with increased C0-2 lordosis, T1S, thoracolumbar junction kyphosis, and pelvic tilt. Cervical reconstruction resulted in decreased C0-2 lordosis, increased T1S, and increased thoracic and thoracolumbar junction kyphosis. Severe cervical kyphosis was associated with greater C0-2 lordosis and postoperative reduction, while severe sagittal malalignment was associated with decreased pelvic tilt and increased lumbar lordosis.