Table 1.
Patient pre-operative demographics
| Variable | RhBMP-2 cohort (n = 64) | Control group (n = 40) | P value* | ||
|---|---|---|---|---|---|
| n | % | n | % | ||
| Agea | 54.8 (19.2–90.1) | 56.5 (22.7–83.3) | 0.693 | ||
| Sex | |||||
| Male | 31 | 48.4 | 12 | 30.0 | 0.070 |
| Female | 33 | 51.6 | 28 | 70.0 | |
| Diagnosisb | |||||
| Degenerative spondylolisthesis | 32 | 50.0 | 22 | 55.0 | 0.689 |
| Degenerative disc disease | 32 | 50.0 | 16 | 40.0 | 0.419 |
| Central stenosis | 27 | 42.2 | 14 | 35.0 | 0.539 |
| Degenerative spondylosis | 5 | 7.8 | 2 | 5.0 | 0.704 |
| Isthmic spondylolisthesis | 2 | 3.1 | 3 | 7.5 | 0.370 |
| Other | 5 | 7.8 | 0 | 0.0 | 0.154 |
| Previous lumbar surgery | 29 | 45.3 | 7 | 17.5 | 0.005 |
| Previous fusion surgery | 15 | 23.4 | 0 | 0.0 | <0.005 |
| Previous spinal rhBMP-2 | 1 | 1.6 | 0 | 0.0 | 1.000 |
Pre-operative age, sex and diagnosis were similar in both cohorts. Patients treated with rhBMP-2 tended to have previous spinal fusion
* P values for categorical variables were generated using Fischer’s exact test
aAge: median (range). Variance in age was determined using two-tailed Student’s t test
bPrimary and secondary pre-operative diagnoses: Patients with one or more diagnosis are included