Abstract
BACKGROUND: Thromboembolic complications in anterior lumbar spinal surgery can rarely result in limb loss. Iliac vessel retraction can temporarily occlude the iliac artery risking thromboembolic sequelae. Studies estimate the incidence of iliac artery thrombosis at 0.45%. Brief intraoperative heparinization can potentially mitigate this risk. We aim to quantify the incidence of temporary iliac artery occlusion (TIAO) and examine its association with potential risk factors (sex, BMI, target disc level, and type of prosthesis). METHODS: Retrospective analysis of consecutive patients undergoing anterior lumbar spinal surgery by a single vascular surgeon and 5 spinal neurosurgeons between 2009 and 2022. Patients underwent single or double-level total disc replacement (TDR); single, double, or triple-level anterior lumbar interbody fusion (ALIF); or hybrid procedure (combined cranial TDR and caudal ALIF). A pulse oximeter monitored bilateral second toes perfusion. Loss of the waveform, combined with a nonpalpable external iliac artery pulse distal to the retractors was defined as TIAO of the ipsilateral artery. Heparin was administered if TIAO developed. RESULTS: Of 605 patients (318 males, 287 females), TIAO occurred in 176 patients (29.1%). TIAO occurred in 13.5% of the 377 patients who underwent single or multilevel ALIF and in 42.7% of the 110 patients who underwent single or multilevel TDR (p=.004). In single-level surgery at L5/S1, TIAO occurred in 3.1% of patients. In single-level surgery at L4/5, TIAO occurred in 65.2% of patients overall; the rate was higher for TDR than for ALIF (74.6% vs. 48.5%; p=.01). The TIAO rate was 44.3% in multilevel procedures and 66.1% in hybrid procedures. No patient developed postoperative thrombotic iliac artery occlusion or embolic complications. CONCLUSIONS: TIAO occurred frequently during anterior lumbar exposure (29%). Anterior spinal exposure at L4/5 had a high incidence of TIAO, particularly for TDR, in contrast to L5/S1.