Table 2.
Characteristics of patients and procedures stratified by the presence or absence of a surgical site infection
| Variable | All patients (N = 245) | Non-SSI (N = 229) | SSI (N = 16) | Odds ratio for SSI (95% CI) | P-value |
|---|---|---|---|---|---|
| Patient-related factors | |||||
| Age at time of surgery (years, mean ± SD) | 62.9 ± 11.3 | 62.7 ± 11.5 | 65.6 ± 6.7 | - | 0.13 |
| Male gender | 162 (66.1%) | 156 (68.1%) | 6 (37.5%) | 0.28 (0.10 – 0.80) | 0.01 |
| BMI (kg/m2, mean ± SD) | 29.2 ± 6.3 | 29.2 ± 6.4 | 30.3 ± 4.6 | - | 0.49 |
| Blood glucose1 (mg/dL, mean ± SD) | 104.9 ± 34.1 (N = 244) | 105 ± 33.6 (N = 228) | 104.1 ± 40.9 | - | 0.92 |
| ASA ≥ 3 | 125 (51.2%) (of N = 244) | 119 (52.2%) (of N = 228) | 6 (37.5%) | 0.55 (0.19 – 1.56) | 0.26 |
| Diagnosis | |||||
| Dystonia | 13 (5.3%) | 12 (5.2%) | 1 (6.3%) | 1.21 (0.15 – 9.90) | 0.59 |
| Essential tremor | 94 (38.4%) | 86 (37.6%) | 8 (50.0%) | 1.66 (0.60 – 4.59) | 0.32 |
| OCD | 6 (2.4%) | 6 (2.6%) | 0 (0%) | - | 1.00 |
| Parkinson’s disease | 131 (53.5%) | 124 (54.2%) | 7 (43.8%) | 0.66 (0.24 – 1.83) | 0.42 |
| Post-stroke thalamic pain syndrome | 1 (0.4%) | 1 (0.4%) | 0 (0%) | - | 1.00 |
| Procedure-related factors | |||||
| Side | |||||
| Bilateral | 219 (89.3%) | 204 (89.1%) | 15 (93.8%) | 1.84 (0.23 – 14.5) | 1.00 |
| Left | 12 (4.9%) | 12 (5.2%) | 0 (0%) | - | 1.00 |
| Right | 14 (5.7%) | 13 (5.7%) | 1 (6.3%) | 1.11 (0.14 – 9.09) | 1.00 |
| Anatomical target | |||||
| GPI | 48 (19.6%) | 45 (19.7%) | 3 (18.8%) | 0.94 (0.26 – 3.45) | 1.00 |
| STN | 98 (40.0%) | 93 (40.6%) | 5 (31.3%) | 0.66 (0.22 – 1.98) | 0.46 |
| VC/VS | 6 (2.4%) | 6 (2.6%) | 0 (0%) | - | 1.00 |
| VIM | 93 (38.0%) | 85 (37.1%) | 8 (50.0%) | 1.69 (0.61 – 4.68) | 0.30 |
| Staged procedure | 228 (92.7%) | 213 (92.6%) | 15 (93.8%) | 1.13 (0.14 – 9.08) | 1.00 |
| Time to second stage (day, median (range)) | 10 (0 – 346) (N = 228) | 10 (0 – 84) (N = 213) | 9 (7 – 346) (N = 15) | - | 0.61 |
| Operation duration2 (minutes, mean ± SD) | 168.3 ± 46.9 (N = 244) | 167.6 ± 47.0 (N = 228) | 178.3 ± 44.5 | - | 0.38 |
| Other factors | |||||
| Antimicrobial prophylaxis | |||||
| Cefazolin | 151 (61.4%) | 140 (61.1%) | 11 (68.8%) | 1.40 (0.47 – 4.16) | 0.54 |
| Nafcillin | 52 (21.1%) | 48 (21.0%) | 3 (18.8%) | 0.87 (0.24 – 3.18) | 1.00 |
| Vancomycin | 17 (6.9%) | 17 (7.4%) | 0 (0%) | - | 0.61 |
| Other | 26 (10.6%) | 24 (10.5%) | 2 (12.5%) | 1.22 (0.26 – 5.70) | 0.68 |
| Topical vancomycin powder | 121 (49.2%) | 117 (51.1%) | 4 (25.0%) | 0.32 (0.10 – 1.02) | 0.04 |
| Postoperative seroma | 1 (0.4%) | 0 (0%) | 1 (6.3%) | - | 0.07 |
| Wound dehiscence | 9 (3.7%) | 5 (2.2%) | 4 (25.0%) | 14.9 (3.5 – 62.9) | < 0.01 |
1
Blood glucose was recorded during a preoperative assessment occurring within the month preceding the procedure.
2
For staged procedures, overall duration was defined as the sum of the time from incision to wound closure for each stage.
ASA: American Society of Anesthesiologists; BMI: body mass index; GPI: globus pallidus interna; Kg/m2: kilograms/meter squared; mg/dL: milligrams/deciliter; OCD: obsessive-compulsive disorder; SD: standard deviation; STN: subthalamic nucleus; SSI: surgical site infection; VC/VS: ventral capsule/ventral striatum; VIM: ventralis intermedius