216. Does interbody fusion at L4-L5 and L5-S1 lead to a lower rate of revision surgery for pseudarthrosis and rod fracture at the lumbosacral junction?

Abstract

<h3>BACKGROUND CONTEXT</h3> Pseudarthrosis and rod fracture at the lumbosacral junction can lead to pain and loss of deformity correction requiring complex revision surgery. Multiple rods spanning the lumbosacral junction and interbody fusion may minimize the risk for pseudarthrosis and instrumentation failure. It remains unclear if interbody fusion at the caudal levels of a long fusion reduces long-term complications. <h3>PURPOSE</h3> To evaluate rates of revision for pseudarthrosis and rod fracture with interbody fusion at L4-L5 and L5-S1, compared to PSF only in long fusion constructs for adult spinal deformity (ASD) surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected single center database. <h3>PATIENT SAMPLE</h3> This study included 367 ASD patients (age: 58 ± 16 y; mFI: .6 ± .7; levels fused: 10.1 ± 4.8) with mean follow-up 68.1 months. <h3>OUTCOME MEASURES</h3> Outcomes evaluated were the rates of revision surgery for pseudarthrosis or rod fracture at the lumbosacral junction. <h3>METHODS</h3> A total of 367 ASD patients were divided into two groups: PSF only (PSF, n=192), and ALIF or TLIF (interbody fusion [IBF], n=175). Patient and surgical characteristics were assessed. Radiographic criteria were evaluated for association with incurrence of pseudarthrosis or rod fracture. <h3>RESULTS</h3> There was no significant difference in patient comorbidities. Estimated blood loss (EBL) was significantly greater in the IBF group (2.4 L vs 1.6 L, p<0.0001). Titanium interbody devices were used in 79.2% of cases and 5.5 mm cobalt chrome rods in 86.4%. There were no differences in BMP utilization. At final follow-up there was no difference in correction of SVA (PSF, IB) (20.5 mm, 32.2 mm, p=0.13), coronal alignment (5.3 mm, 6.7 mm, p=0.65), or lumbar lordosis (6.9°, 9.9°, p=0.29) compared to preoperative baseline. There was no difference in rates of rod fracture at the lumbosacral junction (13.5%, 17.7%, p=0.27), or revision surgery for L4-L5 or L5-S1 pseudarthrosis (7.3%, 10.9%, p=0.23), sagittal malalignment (3.1%, 0.5%, p=0.07), or PJK (4.2%, 6.3%, p=0.36). There was no difference in the rate of neurologic complications between the two groups (19.8%, 28%, p=0.17), or rate of revision surgery for neurologic complications (3.1%, 4.6%, p=0.47). <h3>CONCLUSIONS</h3> At long-term follow-up in a cohort of single institution patients, there were no differences in maintenance of deformity correction, or revision rates for rod fracture, pseudarthrosis, PJK, or neurologic complications when interbody fusion was utilized. The utilization of interbody technique at the lumbosacral junction is not clearly superior to posterior fusion only. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.