Table 2

Surgical demographics.

CharacteristicFrequency, n (%)
Indication for fusiona
 Instability585 (57.4)
 Foramen stenosis486 (47.7)
 Adjacent segment disease161 (15.8)
 Correct painful deformity195 (19.1)
 Nonunion19 (1.9)
 Large, painful, or recurrent disc2 (0.2)
 Discogenic back pain9 (0.9)
 Failed back surgery syndrome50 (4.9)
 Missing or not recorded24 (2.4)
Number of levels fusedb
 1 Level711 (69.8)
 2 Levels209 (20.5)
 3 Levels52 (5.1)
 4 Levels35 (3.4)
 5 Levels12 (1.2)
Levels fused
 L5-S1396 (38.9)
 L4-L5591 (58.0)
 L3-L4291 (28.6)
 L2-L3150 (14.7)
 L1-L257 (5.6)

  • ↵a Many cases had more than 1 indication for fusion.

  • ↵b Indicates number of levels that underwent posterior interbody fusion, case by case.