Table 1 Type and corresponding number of elements used in different finite element models of the lumbosacral spine
INTACT | NOR LYTIC | M-DEG LYTIC | M-DEG-COL LYTIC | S-COL LYTIC | ||
|---|---|---|---|---|---|---|
Nodes | 308,539 | 320,256 | 320,256 | 382,025 | 382,025 | |
Brick element (4-noded tetrahedrons) | 1,454,554 | 1,522,196 | 1,522,196 | 1,811,798 | 1,811,798 | |
Facet articulation (Nonlinear point contact elements) | 5 per joint | 5 per joint | 5 per joint | 5 per joint | 5 per joint | |
Bilateral L5 lytic defect (Zero gap elements) | 0 | 25 per side | 25 per side | 25 per side | 25 per side | |
Annulus fibres (cylindrical beam elements) | L1-L2 | (O) 312–321–293-266 (I) | (O) 289–272–229-224 (I) | (O) 289–272–229-224 (I) | (O) 350–311–279-262 (I) | (O) 350–311–279-262 (I) |
L2-L3 | (O) 362–385–347-287 (I) | (O) 271–266–254-168 (I) | (O) 271–266–254-168 (I) | (O) 359–316–268-255 (I) | (O) 359–316–268-255 (I) | |
L3-L4 | (O) 330–298–232-240 (I) | (O) 265–244–212-189 (I) | (O) 265–244–212-189 (I) | (O) 395–318–269-258 (I) | (O) 395–318–269-258 (I) | |
L4-L5 | (O) 308–331–303-237 (I) | (O) 251–218–233-163 (I) | (O) 251–218–233-163 (I) | (O) 385–322–284-253 (I) | (O) 385–322–284-253 (I) | |
L5-S1 | (O) 243–258–236-219 (I) | (O) 202–192–169-167 (I) | (O) 202–192–169-167 (I) | (O) 436–352–341-291 (I) | (O) 436–352–341-291 (I) | |
Ligaments per level (cylindrical beam elements) | ALL | 14 | 14 | 14 | 14 | 14 |
PLL | 6 | 6 | 6 | 6 | 6 | |
TL | 16 | 16 | 16 | 16 | 16 | |
LF | 18 | 18 | 18 | 18 | 18 | |
ISL | 9 | 9 | 9 | 9 | 9 | |
SSL | 4 | 4 | 4 | 4 | 4 | |
CL | 24 per joint | 24 per joint | 24 per joint | 24 per joint | 24 per joint | |
ILL | 20 | 20 | 20 | 20 | 20 | |
LSL | 22 | 22 | 22 | 22 | 22 | |