RESUMO
STUDY DESIGN: Retrospective case-control study. PURPOSE: To examine the hypothesis that the misuse of thrombin-containing local hemostatics (TCLH) increases the risk of postoperative spinal epidural hematoma (POSEH). OVERVIEW OF LITERATURE: Many studies have focused on hypocoagulability as a risk factor for POSEH. However, there are no prior reports on the increased risk of POSEH in hypercoagulable states. METHODS: Posterior instrumented lumbar spine surgery cases over 2 consecutive years were divided into two groups: a study group (98 patients in whom TCLH was used) and a control group (176 patients in whom TCLH was not used). The excess TCLH matrix that was not associated with blood clot was not removed from the patients in the study group. The senior author decided whether to use TCLH or not. Suction drains were used in all patients. The demographics, coagulation-related factors, and intraoperative factors of the patients in the two groups were analyzed. The development of POSEH was compared between the two groups. RESULTS: The two groups were homogenous in demographics (age and sex), coagulation-related factors (platelet count, prothrombin time, activated partial thromboplastin time, and platelet function analysis), and surgical factors (total blood loss, operation time, blood loss/10 minutes, number of fusion segments, posterolateral fusion/posterior lumbar interbody fusion, and virgin or revision surgery). POSEH developed more frequently in the patients in the study group than in those in the control group (14/98 patients, 14.3% vs. 3/176 patients, 1.7%, respectively; p=0.001; odds ratio, 17.1). CONCLUSIONS: TCLH causes blood clot not only at the edge of damaged vessels but also at the site of extravascular blood. Excess TCLH matrix not associated with blood clot at the epidural space can enhance POSEH development because early clotted hematomas do not drain through suction drains.
RESUMO
BACKGROUND: Previous reports have observed differences only in infection rates between posterolateral fusion and posterior lumbar interbody fusion (PLIF). There have been no reports that describe the particular features of surgical site infection (SSI) in PLIF. In this study, we endeavor to identify the distinguishing characteristics and risk factors of SSI in PLIF. METHODS: Our study undertook a review of a case series of an institute. Patients who had undergone PLIF consecutively in the author's hospital were reviewed. Two proactive procedures were introduced during the study period. One was irrigation of the autolocal bone, and the other was the intradiscal space irrigation with a nozzle. Infection rate and risk factors were analyzed. For subgroup analysis, the elapsed time to a diagnosis (ETD), clinical manifestations, hematologic findings, and causative bacteria were examined in patients with SSI. RESULTS: In a total of 1,831 cases, there were 30 cases of SSI (1.6%). Long operation time was an independent risk factor (p = 0.008), and local bone irrigation was an independent protective factor (p = 0.001). Two cases of referred SSI were included in the subgroup analysis. There were 6/32 (19%) superficial incisional infections (SII), 6/32 (19%) deep incisional infections (DII), and 20/32 (62%) organ/space infections (O/SI). The difference of incidence among three groups was significant (p = 0.002).The most common bacteria encountered were methicillin-resistant Staphylococcus epidermidis followed by methicillin-resistant S. aureus in incisional infections, and no growth followed by S. epidermidis in O/SI. ETD was 8.5 ± 2.3 days in SII, 8.7 ± 2.3 days in DII and 164.5 ± 131.1 days in O/SI (p = 0.013). CONCLUSIONS: The rate of SSI in PLIF was 1.6%, with the most common type being O/SI. The causative bacteria of O/SI was of lower virulence than in the incisional infection, and thus diagnosis was delayed due to its latent and insidious feature. Contamination of auto-local bone was presumed attributable to the progression of SSI. Irrigation of auto-local bone helped in the reduction of SSI.