Table 5: Fixed versus nonfixed segments*


Parameter	Cnull fixed (n = 11) mean (SD)	Cnull nonfixed (n = 11) mean (SD)	Cnull (n = 11) P value * *	Csau fixed (n = 12) mean (SD)	Csau nonfixed (n = 12) mean (SD)	Csau (n = 12) P value * *	CFG fixed (n = 55) mean (SD)	CFG nonfixed (n = 55) mean (SD)	CFG (n = 55) P value * *

Osteophytes/animal ^§	2.3 (1.4)	1.8 (1.7)	0.39 ^†	1.3 (1.5)	0.8 (1.0)	0.27 † †	3.1 (1.2)	2.4 (1.4)	<.0001 ^† ^, ^@

Severity osteophytes	0.8 (0.7)	0.6 (0.6)	0.23 ^‡	0.4 (0.5)	0.3 (0.4)	0.22 ^‡	1.4 (0.8)	0.8 (0.6)	<.0001 ^‡, @ @

ASD/animal ^#	2.0 (2.5)	1.6 (2.1)	0.55 † †	1.8 (1.6)	1.2 (1.3)	0.18 † †	6.4 (2.3)	5.1 (2.5)	<.0001 ^‡, @ @

Severity ASD	0.3 (0.5)	0.2 (0.3)	0.69 ^‡	0.3 (0.2)	0.2 (0.2)	0.25 ^‡	1.6 (0.8)	0.9 (0.5)	<.0001 † † ^, @ @

Parameter

Cnull fixed (n = 11) mean (SD)

Cnull nonfixed (n = 11) mean (SD)

Cnull (n = 11) P value *

Csau fixed (n = 12) mean (SD)

Csau nonfixed (n = 12) mean (SD)

Csau (n = 12) P value *

CFG fixed (n = 55) mean (SD)

CFG nonfixed (n = 55) mean (SD)

CFG (n = 55) P value *

Osteophytes/animal ^§

2.3 (1.4)

1.8 (1.7)

0.39 ^†

1.3 (1.5)

0.8 (1.0)

0.27 †

3.1 (1.2)

2.4 (1.4)

<.0001 ^† ^, ^@

Severity osteophytes

0.8 (0.7)

0.6 (0.6)

0.23 ^‡

0.4 (0.5)

0.3 (0.4)

0.22 ^‡

1.4 (0.8)

0.8 (0.6)

<.0001 ^‡, @

ASD/animal ^#

2.0 (2.5)

1.6 (2.1)

0.55 †

1.8 (1.6)

1.2 (1.3)

0.18 †

6.4 (2.3)

5.1 (2.5)

<.0001 ^‡, @

Severity ASD

0.3 (0.5)

0.2 (0.3)

0.69 ^‡

0.3 (0.2)

0.2 (0.2)

0.25 ^‡

1.6 (0.8)

0.9 (0.5)

<.0001 † ^, @

Cnull, control group-surgery only (no spinal attachment units placed); Csau, control group-spinal attachment units placed during surgery; CFG, combined fixation group; ASD, articular surface degeneration; Z, Zygapophysial.

*Expressed as P values from paired t test or Wilcoxon matched-pairs signed-rank test. Paired t test used for nominal data that was Gaussian in distribution; Wilcoxon test used for ordinal data (0–3 scale) or when nominal data was not Gaussian in distribution.

§Number of Z joints with osteophytes/animal (degeneration occurrence parameter).

†Paired t test.

@Significant.

‡Wilcoxon matched-pairs signed-rank test.

#Number of articular surfaces with ASD/animal (degeneration occurrence parameter).