Table 4.
Strong-, moderate-, limited- and conflicting-evidence independent risk factors associated with patients developing SSI after spinal surgery
| Evidence level | Independent risk factors related to SSI | Infected patients number of high-quality studies | Infected patients number of moderate-quality studies | Infected patients number of low-quality studies |
|---|---|---|---|---|
| Strong evidence | Obesity/BMI | 1,256 [18, 26, 33, 39, 40, 42, 44, 56] | 201 [13, 43, 47, 52] | 63 [35, 60, 61] |
| Longer operation time | 1,107 [8, 10, 17, 33, 42, 56] | 31 [12, 61] | ||
| Diabetes | 1,163 [17, 18, 26, 40, 42, 50, 56, 57] | 8 [14] | 127 [11, 24, 27, 28, 30, 61] | |
| Smoking | 836 [17, 50, 56] | 22 [61] | ||
| History of previous SSI | 226 [17, 42, 44] | |||
| Type of surgery procedure | 470 [1, 33, 39, 42] | 20 [43] | 62 [2, 27] | |
| Moderate evidence | Spinal level of surgery | 41 [18] | 63 [13] | |
| Number of spinal levels operated | 229 [1, 50] | 39 [28, 35] | ||
| Surgery involving the sacrum or pelvis | 297 [1, 33] | |||
| Larger intraoperative blood loss | 216 [26, 42] | 31 [12, 61] | ||
| Surgery with spinal instrumentation | 856 [33, 56] | 127 [12, 24, 27, 28, 58] | ||
| Previous surgery | 52 [10, 50] | |||
| Blood transfusions | 752 [56] | 61 [52] | ||
| ASA classification | 856 [33, 56] | |||
| Limited evidence | Hypertension | 63 [13] | ||
| Invasiveness index | 63 [13] | |||
| Renal disease | 63 [13] | |||
| Bony or connective tissue neoplasm | 193 [1] | |||
| Skin to lamina distance | 24 [35] | |||
| Thickness of subcutaneous fat | 24 [35] | |||
| Surgical case order | 216 [21] | |||
| Drain duration | 57 [47] | |||
| Male gender | 57 [47] | |||
| Hemodialysis | 9 [12] | |||
| Albumin count | 16 [10] | |||
| Trauma | 14 [57] | |||
| Insufficient intraoperative irrigation | 14 [57] | |||
| Dependent functional status | 752 [56] | |||
| Disseminated cancer | 752 [56] | 46 [58] | ||
| Presence of comorbidities | 139 [8, 26] | |||
| Preoperative irradiation | 8 [14] | |||
| Exposure to razor shaving | 104 [33] | |||
| Intraoperative administration of a FiO2 less than 50 % | 104 [33] | |||
| Suboptimal timing of prophylactic antibiotic therapy | 56 [40] | |||
| Pre-/post-operative elevated serum glucose level | 56 [40] | 6 [30] | ||
| Age | 48 [17] | 57 [24, 27] | ||
| Alcohol abuse | 48 [17] | 57 [25, 61] | ||
| Dural tear | 84 [26] | 13 [3] | ||
| The use of glue to cement the dural patch | 13 [3] | |||
| Postoperative incontinence | 41 [39] | |||
| Surgery for tumor resection | 41 [39] | |||
| Complete neurologic deficit | 12 [48] | |||
| Steroid therapy | 22 [61] | |||
| Extended preoperative hospitalization | 22 [61] | |||
| Indication for surgery | 9 [34] | |||
| Conflicting evidence | The number of resident surgeons participating in the operative procedure | 212 [5, 26, 40] |