180. Who bleeds during elective anterior lumbar surgery?

Abstract

<h3>BACKGROUND CONTEXT</h3> Blood loss during elective anterior lumbar access for interbody fusion or disc replacement is a potentially major complication. Patients undergoing this surgery have a variety of co-morbidities and medication which may contribute. <h3>PURPOSE</h3> The aim of this study was to examine which factors effect intraoperative estimated blood loss (EBL) during anterior lumbar surgery. <h3>STUDY DESIGN/SETTING</h3> A prospective study of consecutive anterior retroperitoneal approaches for lumbar surgery was performed between January 2010 and November 2021, by a single vascular surgeon and a single spine surgeon. <h3>PATIENT SAMPLE</h3> All patients (n=368) underwent an anterior lumbar interbody fusion (ALIF) at L4–5 and/or L5–S1, a total disc replacement (TDR) at L4–5 and/or L5–S1, or a hybrid procedure with a TDR at L4–5 and an ALIF at L5–S1. <h3>OUTCOME MEASURES</h3> We examined the effects of patient age, sex, body mass index (BMI), low-dose aspirin (LD-ASA), operative level, prosthesis and intraoperative heparinization. <h3>METHODS</h3> The Cell Saver was used in all cases with blood loss measured and recorded by an independent autotransfusionist. Saturation probes were placed on the second toes bilaterally. Heparin was administered intravenously when the saturation meter signal lost pulsatility indicating lower limb arterial flow was interrupted. <h3>RESULTS</h3> The mean age of the 368 patients was 47 ± 13.2 yrs [95% CI = 45 – 48]; and 210 (57%) were male. BMI showed a negative association with EBL. Age showed no effect on EBL in non-heparinized patients but a negative trending correlation with EBL in heparinized patients. Continuation of LD-ASA did not significantly affect EBL. Most patients underwent an ALIF (265 patients,72%), 55 (15%) had a TDR, and 48 (13%) had a hybrid operation (with a TDR at L4–5 and an ALIF at L5–S1) and the majority (249 patients,68%) had a single-level procedure (54 (26.9%) at L4–5 and 195 (73.1%) at L5–S1) and 119 (32%) underwent a 2-level procedure (L4–5 and L5–S1). There was more than twice mean EBL with TDR (135ml) and hybrid (104ml) compared to ALIF (59ml) but were not statistically significant. Intraoperative heparinization was administered in 104 patients (28%). The total mean EBL for the heparin group (125ml) was significantly higher than for the non-heparin group (56ml) (p< 0.0004). A significant difference was observed when comparing heparin vs nonheparin patients and the procedure type. With ALIF (p < 0.002), TDR (p< 0.03) and hybrid (p< 0.02) there was a significantly higher EBL with heparinized patients compared to nonheparinized patients. <h3>CONCLUSIONS</h3> TDR showed the highest EBL across procedure types. In non-heparinized patients, older age, increasing BMI and continuation of LD-ASA were not predictors for increased EBL. However, in heparinized patients, age and BMI showed a negative correlation with increased EBL. This study suggested younger, leaner, heparinized patients who undergo TDR surgery demonstrated the highest EBL risk in anterior lumbar surgery. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.