212. ALIF as a salvage procedure for TLIF pseudarthrosis: a clinical outcome study

Abstract

<h3>BACKGROUND CONTEXT</h3> Lumbar fusion procedures are at risk for pseudarthrosis as a complication. Despite its relative prevalence, few studies have characterized the clinical efficacy of salvage procedures. <h3>PURPOSE</h3> To characterize clinical outcomes following anterior lumbar interbody fusion (ALIF) as a salvage procedure for pseudarthrosis of transforaminal lumbar interbody fusion (TLIF). <h3>STUDY DESIGN/SETTING</h3> Retrospective. <h3>PATIENT SAMPLE</h3> Thirty-four ALIF patients. <h3>OUTCOME MEASURES</h3> VAS back and leg, ODI, SF-12 PCS, VR-12 PCS. <h3>METHODS</h3> A retrospective review of a surgical database of eligible procedures between November 2010 and June 2020 was performed. Inclusion criteria were as follows: single-level revision ALIF procedures performed at the index level for pseudarthrosis of TLIF. Patients were excluded if procedures were primary or performed for infectious, malignant or traumatic etiologies. Demographic and perioperative characteristics were collected. Additionally, time to revision, rates of 1-year arthrodesis, 6-month pseudarthrosis and postoperative complications were calculated. Radiographic measurements were performed to evaluate sagittal alignment and disc height at the preoperative, immediate postoperative and final postoperative timepoint. Differences between preoperative and final postoperative radiographic measurements were evaluated using a Student's t-test. Visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), 12-Item Short Form physical composite score (SF-12 PCS and VR-12 PCS) were collected preoperatively and postoperatively. Overall achievement of a minimum clinically important difference (MCID) was calculated using the following established values: 1.2 (VAS Back), 1.6 (VAS leg), 12.8 (ODI), 4.0 (SF-12 PCS). <h3>RESULTS</h3> A total of 34 patients who underwent an ALIF revision procedure at the index level were identified. Mean age was 46.7 years with 81.1% being male and 64.9% obese (body mass index: 30 kg/m²). A total of 83.8% had an ASA < 2 and 75.5% carried a CCI > 1. Mean time from index TLIF to salvage ALIF procedure was 21.3 months. Mean operative time was 135.3 minutes with an average blood loss of 75.0mL and hospital length of stay of 49.5 hours. The majority of procedures were performed at the L5-S1 level (73.5%). Patients demonstrated a one-year arthrodesis rate of 100.0% with 2/34 patients requiring an additional revision procedure at the index level for neuroforaminal bone growth. A total of six postoperative complications were observed with one patient suffering from a mild urinary tract infection, one with acute renal failure, one with a venous thromboembolism, one with altered mental status, and two with fever of unknown origin. Following ALIF salvage, there was a significant increase in segmental lordosis, mean anterior and posterior disc height, as well as average disc height (p≤0.037, all). Mean preoperative outcome scores were 7.2 ± 1.9 for VAS back, 6.8 ± 2.8 for VAS leg, 56.7 ± 16.5 for ODI, and 28.1 ± 10.9 for SF-12 PCS. Clinically relevant improvement of PROMs as measured by MCID achievement rates by one-year were 67.1% for VAS back, 57.1% for VAS leg, 40.0% for ODI and 37.5% for SF-12 PCS. <h3>CONCLUSIONS</h3> Use of ALIF as a salvage procedure at either the L4-5 or L5-S1 level for TLIF pseudoarthrosis demonstrated a high arthrodesis rate at one-year. Patients demonstrated high rates of MCID achievement for back and leg pain, as well as ODI. These results support the use of ALIF as a salvage procedure for failed TLIFs at the L4-5 and L5-S1 levels. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.