Does kyphoplasty affect the global sagittal alignment in patients with osteoporotic vertebral fractures? A systematic review and meta-analysis.

ABSTRACT

BACKGROUND: Osteoporotic vertebral compression fractures (OVCF) are common in elderly patients and may cause local kyphosis due to the vertebral collapse and wedging. Balloon kyphoplasty (BKP) with polymethyl methacrylate is widely used to relieve back pain and restore the height and kyphosis of the destroyed vertebra Johnell (Osteoporos Int 17(12)1726-33, 2006); Wasnich (Bone 18 179S-183S, 1996); Finnern (Osteoporos Int 14429-436, 2003). However, the influence of BKP on global sagittal alignment (GSA) in patients with OVCF remains unclear. OBJECTIVE: To systematically evaluate the relevant literature regarding the influence of BKP on the global spinal sagittal alignment using the following radiological parameters Pelvic Incidence (PI), Pelvic Tilt (PT), Lumbar Lordosis (LL), Thoracic Kyphosis (TK), Sagittal Vertical Axis (SVA) and Spinosacral Angle (SSA). Visual Analogue Score (VAS) was also recorded. METHODS: A systematic review of the English language literature dating up until August 2022, was undertaken utilising the PRISMA guidelines. RESULTS: Of a total of 548 articles, 4 studies met the inclusion criteria (4 level III evidence) and were analyzed. Overall, 201 patients of mean age 73.8 years (69-77) had acute OVCF of one or more vertebra. The male to female ratio was 51128. The number of fractured vertebrae was 235 (average of 1.17 fractured vertebrae per patient). Their pre-operative radiological parameters on standing x-rays showed a mean PI of 56°, PT 24.1°, LL 44.4°, TK 42.3°, PI-LL 11.7°, SVA 4.9 cm, LL/TK 1 and SSA 114.8°. The average VAS was 7.6 (2.6-10). All the patients underwent BKP and their radiological parameters on standing x-rays post operatively showed a mean PI of 55.3°, PT 23.1°, LL 45.1°, TK 41.4°, PI-LL 10.3°, SVA 4.29 cm, LL/TK 1.07 and SSA 116.8°. Their average VAS post BPK was 2.36 (0-4.8).A statistical analysis comparing the pre/post-operative GSA (111 patients, 3 studies with standard deviations) showed no statistical difference in PT (24.1° vs. 23.5°, P = 0.93), TK (42.3° vs. 42.4°, P = 0.57), PI-LL (14.4° vs.12.4°, P = 0.4), SVA (6.1 cm vs. 5.5 cm, P = 0.19) SSA (114.8° vs. 116.7° P = 0.36). VAS was significantly reduced post BKP (7.1 vs. 2.5 P = 0.004). CONCLUSION: Performing BKP procedures does not significantly affect the global sagittal alignment in patients with osteoporotic vertebral compression fractures. There was however, a significant improvement in pain scores in patients undergoing BKP at 1 or more levels.