Table 2.
Patient, Operative, and Hospital Characteristics Associated with Receipt of Intra-Wound Antibiotics during their Initial Operation
| No intra-wound antibiotics | Intra-wound antibiotics | ||||
|---|---|---|---|---|---|
| n = 4,464 | n = 5,359 | ||||
| Count | % | Count | % | p | |
| Patient characteristics | |||||
| Mean age | 58 | 58 | 0.80a | ||
| Male | 2,084 | 47% | 2457 | 46% | 0.41b |
| Mean body mass index (kg/m2) | 29.8 | 30.2 | <0.01 | ||
| Race: White | 3,870 | 87% | 4,714 | 88% | 0.06 |
| Private insurance | 2,970 | 67% | 3,779 | 71% | <0.01 |
| Current smoker | 3,995 | 22% | 4,833 | 19% | <0.01 |
| Low albumin (≤3.5 mg/dL) | 133 | 3% | 180 | 3% | 0.29 |
| Comorbid conditions | |||||
| Degenerative disk disease | 1,093 | 24% | 1,141 | 21% | <0.01 |
| Prior surgery | 807 | 18% | 857 | 16% | <0.01 |
| Hypertension | 2,365 | 53% | 2,792 | 52% | 0.38 |
| Diabetes | 778 | 17% | 909 | 17% | 0.55 |
| Asthma | 653 | 15% | 759 | 14% | 0.51 |
| Sleep apnea | 789 | 18% | 748 | 14% | <0.01 |
| Coronary artery disease | 412 | 9% | 430 | 8% | 0.04 |
| SSI after previous spine surgery | 29 | 1% | 26 | 0% | 0.28 |
| Osteoporosis | 111 | 3% | 98 | 2% | <0.01 |
| Home medications | |||||
| Statin | 1,412 | 32% | 1,716 | 32% | 0.68 |
| Beta blocker | 942 | 21% | 1,099 | 21% | 0.46 |
| ACE-I or ARB | 1,479 | 33% | 1,819 | 34% | 0.41 |
| Therapeutic anticoagulation | 119 | 3% | 140 | 3% | 0.87 |
| Steroids | 178 | 4% | 191 | 4% | 0.28 |
| Narcotics | 2,246 | 50% | 3,056 | 57% | <0.01 |
| Infection prophylaxis measures | |||||
| Maintenance of euglycemia | |||||
| Insulin started for hyperglycemiac | 110 | 45% | 105 | 44% | 0.93 |
| Glucose tested among diabetics | 588 | 76% | 610 | 67% | <0.01 |
| On-time antibioticsd | 2,289 | 99% | 2,902 | 99% | 0.38 |
| Euthermia (36+) | 4,188 | 97% | 4,818 | 97% | 0.73 |
| Operative/hospital characteristics | |||||
| Open surgical approach | 4,171 | 94% | 5,069 | 95% | 0.03 |
| Invasiveness indexe | 9.11 | 9.16 | 0.54 | ||
| Anatomic location | |||||
| Cervical | 2,146 | 48% | 2,500 | 47% | 0.16 |
| Lumbar | 2,318 | 52% | 2,859 | 53% | |
| Surgeon type | |||||
| Neurosurgeon | 1,940 | 44% | 3,365 | 63% | <0.01 |
| Orthopedic surgeon | 2,496 | 56% | 1,939 | 36% | |
| Unknown | 28 | 1% | 55 | 1% | |
| Operation duration (hours) | |||||
| ≤2 | 1,449 | 33% | 1,969 | 37% | <0.01 |
| 2–4 | 1,929 | 43% | 2,445 | 46% | |
| >4 | 1,070 | 24% | 921 | 17% | |
| Academic hospital | 3,224 | 72% | 3,245 | 61% | <0.01 |
a
Comparison using Student t test for continuous variables.
b
Comparison of patients who did and did not receive intra-wound antibiotics using χ2 tests for heterogeneity unless otherwise indicated.
c
Hyperglycemia defined as >180 mg/dL.
d
This number describes the proportion of patients who received on-time antibiotics, among those who had this recorded. This was not included as a metric in 2013.
e
Based on number of instrumentation levels, decompressive levels and fusion levels.
SSI = surgical site infection; ACE- I = angiotensin converting enzyme inhibitor; ARB = antiogensin II receptor blockers.