Postoperative alterations of sagittal cervical alignment and risk factors for cervical kyphosis in 124 Lenke 1 adolescent idiopathic scoliosis patients

Incidence of Cervical Kyphosis and Factors Associated with Improvement in Postoperative Cervical Spinal Alignment in Idiopathic Scoliosis with Major Thoracolumbar/Lumbar and Thoracic Curves

Background: This study aimed to compare the incidence and severity of cervical kyphosis before and after surgery between patients with adolescent idiopathic scoliosis (AIS) with major thoracolumbar/lumbar curves (Lenke type 5C group) and those with major thoracic curves (Lenke type 1A group). Further, factors associated with cervical spinal alignment changes after surgery in the two groups were examined. Methods: This study included consecutive patients with AIS who underwent posterior spinal fusion for Lenke type 1A and 5C curves and who were followed up for at least 1 year. To measure changes in sagittal alignment, all patients underwent radiography before, immediately after, and at 1 year after surgery. The correlation coefficients change the value of the C2-C7 angle before and after surgery (ΔC2-ΔC7) and other spinopelvic parameters were examined. Results: In total, 19 of 30 patients in the Lenke type 1A group and 21 of 36 in the Lenke type 5C group presented with cervical kyphosis preoperatively. Hence, the incidence of cervical kyphosis did not significantly differ between the two groups. Further, the two groups had significantly higher thoracic kyphosis (TK) and greater C2-C7 angles postoperatively. The TK of the Lenke type 5C group further increased at 1 year postoperatively. The Lenke 1A type group presented with a significant re-decrease in the C2-C7 angle at 1 year postoperatively. However, the C2-C7 angle of the Lenke type 5C group did not change. The ΔTK was closely associated with the ΔC2-ΔC7 in the Lenke type 1A group, but not in the Lenke type 5C group. Conclusions: In thoracic AIS, postoperative cervical alignment should achieve an adequate TK and promote correction of the coronal plane curve. Moreover, selective corrective surgery can improve postoperative cervical alignment in lumbar AIS.

Neck and shoulder pain in thoracic adolescent idiopathic scoliosis 10 years after posterior spinal fusion

PURPOSE

We aimed to determine the clinical significance of neck and shoulder pain (NSP) 10 years after posterior spinal fusion (PSF) for thoracic adolescent idiopathic scoliosis (AIS) and the relationship between radiographic parameters and NSP.

METHODS

Of 72 patients who underwent PSF for thoracic AIS (Lenke 1 or 2) between 2000 and 2013, we included 52 (46 females; Lenke type 1 in 34 patients and type 2 in 18; mean age, 25.6 years) who underwent NSP evaluation using visual analog scale (VAS, 10 cm) 10 years postoperatively (follow-up rate, 72.2%). Correlation analyses were performed using Spearman's rank correlation coefficient (r).

RESULTS

The VAS for NSP was 2.6 cm in median and 3.4 cm in mean at 10 years. The VAS had significant negative correlations with several SRS-22 domain scores (rs = - 0.348 for pain, - 0.347 for function,  -  0.308 for mental health, and - 0.372 for total) (p < 0.05). In addition, the VAS score was significantly correlated with cervical lordosis (CL) (rs = 0.296), lumbar lordosis (rs = - 0.299), and sacral slope (rs = 0.362) (p < 0.05). Furthermore, at the 10-year follow-up, CL was significantly negatively correlated with T1 slope (rs = - 0.763) and thoracic kyphosis (TK) (- 0.554 for T1-12 and - 0.344 for T5-12) (p < 0.02).

CONCLUSION

NSP was associated with deterioration in SRS-22 scores, indicating that NSP is a clinically significant long-term issue in PSF for thoracic AIS. Restoring or maintaining the TK and T1 slopes, which are controllable factors during PSF, may improve cervical lordosis and alleviate NSP at 10-year follow-up.

Statistical modelling of how the sagittal alignment of the cervical spine is affected by adolescent idiopathic scoliosis and how scoliosis surgery changes that

The relationship between the sagittal shape of the cervical spine and that of the thoracolumbar spine is established in the normal spine. Adolescent idiopathic scoliosis (AIS) is recognised as a change in the shape of the spine in both the coronal and sagittal planes. The effects of AIS on the alignment of the cervical spine, including the effects of surgery, has been less well studied. The objective of this study was to identify, using regression analysis, the significant relationships between the alignment of the thoracolumbar spine, in both the coronal and sagittal planes, and the sagittal alignment of the cervical spine in AIS. This study used coronal and sagittal radiographic measures from a group with AIS, both pre and post-operatively, which were analysed using multiple linear regression methods to identify significant parameters that explain the sagittal shape of the cervical spine. There were 51 pairs of pre and post-operative radiographs analysed, 40 of which were Lenke 1 curves and 11 Lenke 3 curves. Posterior spinal fusion was performed for all. The significant parameters pre-operatively were T1 slope, thoracic kyphosis, lumbar lordosis and SVA with an R2 value of 78%. Post-operatively, the significant parameters were T1 slope, thoracic kyphosis, lumbar lordosis and thoracolumbar scoliosis with an R2 of 63%. The sagittal alignment of the cervical spine in AIS is related to the shape of key parameters in the rest of the spine. Changes in the cervical sagittal shape occur to compensate for changes in shape to the rest of the spine that occur as a consequence of surgery. This has implications for the understanding of how the compensatory mechanisms of the spine are used to maintain a horizontal gaze, along with prediction of the effects of surgery on the shape of the spine.