The assessment of the postoperative spinal alignment: MRI adds up on accuracy

Abstract

Introduction The sagittal profile of conventionally and surgically treated scoliotic spines is usually analyzed via lateral views of whole-spine X-rays in an upright position. Due to a more hypokyphotic configuration of scoliotic spines, the view onto the upper thoracic vertebrae is often difficult. We investigated whether additional supine MRI measurement supports valid kyphosis angle measurement. Patients and methods Twenty patients with either short (n = 10, Halm-Zielke, VDS) or long spondylodesis (n = 10, dorsoventral) were assessed 5 years after surgery with standing radiographs and supine whole-spine MRI. Results Up to 90% of the upper thoracic vertebrae were invisible on radiographs, whereas MRI allowed visibility of almost many vertebrae. No significant difference in thoracal kyphosis angles could be observed in the comparison of X-ray and MRI data. Conclusion Thoracal kyphosis measurement of postoperative spines in MRI is a valid diagnostic tool with reliability comparable to that of X-ray. These results cannot be transferred to lumbar lordosis measurement and transferred only partly to coronal COBB angle measurement.

Comparison of Lumbar Lordosis in Lateral Radiographs in Standing Position with supine MR Imaging in consideration of the Sacral Slope

“…Inter-observer reliability was higher in MRI than in X-ray measurements, which may lead to the conclusion that MR images can be measured more precisely [19]. However, we only measured one midline-copied image to make sure to always measure the same layer of an MR image.…”

Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques

“…It has been shown also that MRI has utility similar to that of radiographs for the assessment of thoracolumbar kyphosis and scoliosis using Cobb angle measurement. 15,96,106,126 However, the reliability and validity of MRI-based Cobb angle measurements for evaluating the cervical region have yet to be established.…”

Thoracal flat back is a risk factor for lumbar disc degeneration after scoliosis surgery

“…Degenerative disc disease was evaluated by a trained spine surgeon (UE) from sagittal plane T2-weighted preoperative MRI and from T2-SPACE-weighted FU MRI sequences (for MRI details, see Bernstein et al [12]) according to the Pfirrmann classification system [14]. A disc degeneration index (DDD index) was averaged for the six caudal-most mobile lumbar segments (eg, Th12-S1).…”

“…For analysis, the SRS22 subscores ''function'' (questions 5,9,12,15,18), ''pain'' (1,2,8,11,17), ''body'' (4,6,10,14,19), ''soul'' (3,7,13,16,20), and ''satisfaction'' (21,22) were extracted. Lateral and anteroposterior standing whole-spine radiographs and FU wholespine MRI were performed as described earlier [12].…”

“…FU coronal balance deviation was measured by the center sacral vertical line (CSVL) distance to the LIV and the C7-CSVL distance (JS). Follow-up sagittal balance (according to the method of Jackson et al [13]), sagittal angles for thoracic kyphosis (Th3-Th11), and lumbar lordosis (L1-S1) were either measured on MRI (thoracic kyphosis) or standing radiographs (thoracic kyphosis, sagittal balance, lumbar lordosis, pelvic parameters; SH, PB, AH, UE), according to an optimized measuring protocol as described earlier [12].…”