**3.5 Curve progression**

Many studies have shown adult scoliosis tends to progress, with the rate of progression higher in DLS than ADIS [46].

DLS tends to progress irrespective of the magnitude of the curve (**Figure 6**) [46]. A study reported the rate of progression of scoliosis in patients with DLS to be 1.64° per year (0.77–3.82°) [7], while another study reported an increase of 3° per year in a cohort of 200 people over the age of 50 years [47]. The radiographic risk parameters are similar to that of ADIS and include apical vertebral rotation ≥ III, a Cobb angle >30°, lateral vertebral translation >6 mm., and L5 above the intercristal line, which is the line joining both iliac crests [9, 47].

### **Figure 6.**

*Progression of degenerative lumbar scoliosis in a postmenopausal woman 70 years of age. In the year 2003 (a), the left lumbar scoliosis measured 30°. It increased to 35° in year 2009 (b). After the patient was prescribed Fosamax by his medical practitioner, the curve stabilized, as can be seen in the radiograph in 2017 (c).*
