Characteristics, survivals and risk factors of surgical site infections after En Bloc sacrectomy for primary malignant sacral tumors at a single center

For prolonged survival, primary malignant sacral tumors (PMST) are treated by En Bloc sacrectomy. Few studies analyzed specifically the surgical site infections (SSI) for this condition and whether they impact on the patients' survivals.The objectives were to (1) describe their characteristics; (2) compare the survivals of infected and non-infected patients; (3) identify patients- and surgery-related risk factors.We conducted a retrospective single center study on 51 consecutive patients with PMST who underwent an En Bloc sacrectomy. Mean follow-up was 89±68months (range, 13-256months). Histology consisted of 46 chordoma, 3 chondrosarcoma, 1 Ewing tumor, 1 malignant peripheral nerve sheet tumor. Mean age was 57.4±13.7years with 26 (51%) male. Approaches were mainly anterior-and-posterior with, for the anterior approach, 18 laparotomy and 32 laparoscopy. Other surgical characteristics included 39 (76%) sacrectomy above S3; 7 (14%) instrumented cases; 8 (16%) colostomy. A pedicled omental flap with artificial mesh was used for posterior wall reconstruction. Overall and disease-free survivals were compared between infected and non-infected patients using Kaplan-Meier curves and log-rank test.A total of 29 (57%) patients developed a SSI (7 deep, 22 organ/space) at mean 13.2±7.7days. One patient had also an infected intraperitoneal hematoma at day 150. SSIs were polymicrobial in 26 (90%) cases with Enterococcus sp. (27%) and E. coli (24%) as predominant organisms. Overall and disease-free survivals were not statistically different between infected and non-infected patients. Factors associated with increased likelihood of SSI included age>65years (OR=3.64; 1.06-12.50; p=0.04) and an elevated ASA score (OR=3.28, 1.05-10.80; p=0.046). Neoadjuvant radiotherapy (OR=2.86; 0.97-9.37; p=0.08) demonstrated a trend towards increased risk of SSI. Tumor volume, sacrectomy level, operating time, laparoscopy, colostomy, instrumentation, bowel incontinence were not associated to an increased risk of SSI.En Bloc sacrectomy for PMST led to frequent and early SSI which, however, did not seem to impact survivals. Preoperative frailty was the predominant risk factor found in this series. Further studies are required to identify protective measures.III, case-control study.