TABLE 1.
Perioperative characteristics of patients undergoing spine surgery in DICON community hospitals overall and by season (January 1, 2007, to December 31, 2012)
| Variables | Overall | June–September | October–May | p Value |
|---|---|---|---|---|
| No. of patients | 57,559 | 18,957 | 38,602 | |
| Median age in yrs (IQR) | 54 (44–65) | 54 (44–65) | 54 (44–64) | 0.18 |
| Median operation duration in mins (IQR) | 113 (74–179) | 112 (74–179) | 113 (74–178) | 0.30 |
| Sex (%) | 0.13* | |||
| Male | 22,691 (49) | 7382 (49) | 15,309 (50) | |
| Female | 23,270 (51) | 7723 (51) | 15,547 (50) | |
| Race (%) | 0.82* | |||
| White | 9191 (78) | 2902 (78) | 6289 (78) | |
| Black | 2244 (19) | 699 (19) | 1521 (19) | |
| Other | 316 (3) | 105 (3) | 211 (3) | |
| Procedure (%) | 0.25 | |||
| Laminectomy | 24,466 (42) | 8122 (43) | 16,344 (42) | |
| Spinal fusion | 33,093 (58) | 10,835 (57) | 22,258 (58) | |
| NHSN risk index (%) | 0.37* | |||
| 0 | 28,605 (50) | 9382 (49) | 19,223 (50) | |
| 1 | 23,496 (41) | 7807 (41) | 15,689 (41) | |
| 2 | 5414 (9) | 1756 (9) | 3661 (10) | |
| 3 | 44 (0.08) | 15 (0.08) | 29 (0.08) | |
| ASA classification (%)† | 0.48* | |||
| 1 | 3884 (7) | 1319 (7) | 2565 (7) | |
| 2 | 30,186 (52) | 9863 (52) | 20,343 (53) | |
| 3 | 21,443 (37) | 7110 (37) | 14,333 (37) | |
| 4 | 2031 (4) | 661 (4) | 1370 (4) | |
| 5 | 15 (0.03) | 4 (0.02) | 11 (0.03) | |
| Infection class (%)‡ | 0.19* | |||
| Superficial incisional | 185 (29) | 77 (32) | 108 (27) | |
| Deep incisional | 352 (55) | 123 (51) | 229 (57) | |
| Organ/space | 104 (16) | 42 (17) | 62 (16) |
IQR = interquartile range.
*
Categorical and ordinal variables were converted into dichotomous variables to calculate p values.
†
American Society of Anesthesiologists physical status classification system.
‡
One SSI during the summer had an unknown infection class and was excluded from this table.