**5. Radiographic examination**

Radiographic examination usually involves taking erect posteroanterior and lateral full spine radiographs. This enables the evaluation of the regional spinopelvic parameters as well as global spinal balance. Sagittal spinal balance has been reported to be positively associated with health-related quality of life (HRQOL) [32, 35].

### **5.1 Frontal spinal radiograph**

A frontal radiograph generally depicts a thoracolumbar or lumbar scoliosis, which is generally shorter than that seen in ADIS, involving only a few vertebral segments. Additionally, vertebral body deformities are less severe than that of ADIS [54]. Of interest is that the majority of lumbar curves with a convexity to the right had apexes above L2 and those with convexities to the left had apexes below L2 [55]. The authors, however, did not offer any explanation for the findings [55].

Depending on the degree of the DLS, radiographic features differ. In the early stages, mild lumbar intervertebral wedging may be present, and compensation in the form of wedging to the opposite direction may be seen in the upper vertebral levels [8].

With progression of the condition, vertebral instability in the form of a translatory shift may be evident [39]. Very often, lateral vertebral translation or laterolisthesis is accompanied by vertebral rotation, when it is known as VRO. VRO most often affects the L3 and L4 levels and less commonly L2–L3 and L4–L5. Of note is that 50% of the VRO occurs at the junction between the main lumbar curve and the compensatory lumbosacral hemicurve [39]. VRO also occurs at the apex of the main lumbar curve and at the junction between the thoracic curve and the lumbar curve [39]. Open subluxation tends to occur on the convexity of the main curve, while closed dislocation tends to occur at the junction between the scoliosis curves [39].

In late stage DLS, osteophytosis may be seen in the vertebral end plates in the concavity of the lumbar scoliosis. Large bridging osteophytes provide stability to previously unstable vertebrae. Also evident are signs of disc degeneration, facet arthrosis, and spinal stenosis [4]. The possibility of lateral recess stenosis and central spinal stenosis may also be discerned from the frontal radiographs. The Cobb

*Conservative Treatment of Degenerative Lumbar Scoliosis DOI: http://dx.doi.org/10.5772/intechopen.90052*

angle and the apical vertebral rotation need to be measured, as they are related to the risk of curve progression and back pain. A lumbar scoliosis in excess of 30°, an apical vertebral rotation in excess of 33%, and lumbarization increase the propensity for curve progression and the incidence of back pain [34].

Pelvic obliquity is common in DLS [50]. From the radiograph, the coronal balance may also be determined. It is the distance between the vertical lines extended from the mid sacrum (central sacral line, CSL) to mid C7. When it is in excess of 4 cm, it is associated with deterioration of pain and function scores in adult scoliosis patients [32, 35]. Of importance is that Ferrero et al. [39] reported that the side of radicular pain corresponded to the side of coronal shift in 70% of the subjects [39].

## **5.2 Lateral spinal radiograph**

Lateral spinal radiography generally reveals a reduction of lumbar lordosis and sagittal imbalance. This is important as regional spinopelvic parameters and global spinal balance have been found to be associated with clinical outcome. A study showed that pelvic incidence-lumbar lordosis (PI-LL) mismatch ≥10° and pelvic tilt ≥22° were reported to correlate with disability [56].

Sagittal spinal imbalance is common in patients with DLS. One of the commonly used parameters is the sagittal vertical axis, which is the distance between the vertical line dropped from C7 and the posterosuperior angle of the sacrum. It is noteworthy that a SVA ≥7 cm. is associated with clinical symptoms [32]. The finding was supported by other studies [36, 56]. In mild and moderate spinal malalignment, patients with DLS tend to incline the trunk forward and tend to develop a posterior pelvic shift to maintain balance and to provide relief from neurologic symptoms, especially in the presence of concomitant degenerative spondylolisthesis [48].
