Clinical characteristics of patients undergoing minimally invasive surgery for ankylosing spondylitis.
| Characteristics | n |
| Age at surgery, y, median (range) | 73 (38–89) |
| Sex, male | 39 |
| American Society of Anesthesiologists classification | |
| 1–2 | 17 |
| 3–4 | 26 |
| Comorbidity | |
| Hypertension | 23 |
| Diabetes mellitus | 10 |
| Coronary artery disease | 10 |
| Lung disease | 8 |
| Asthma | 5 |
| Chronic obstructive pulmonary disease | 3 |
| Malignancy | 7 |
| Neurological disease | |
| Cerebellar ataxia | 1 |
| Dementia | 2 |
| Cerebrovascular disease | 2 |
| Alcohol abuse | 4 |
Note: Data presented as n unless otherwise noted.