Does Anterior Lumbar Interbody Fusion Reduce Mechanical Complication and Pseudarthrosis Rate at the Lumbosacral Junction in Adult Spinal Deformity Surgery in Comparison to Posterior Lumbar Interbody Fusion?

Background: To evaluate the impact of anterior lumbar interbody fusion (ALIF) vs posterior lumbar interbody fusion (PLIF) at the lumbosacral junction on mechanical complications and fusion rate at the caudal lumbar segments in adult spinal deformity (ASD) surgery.

Methods: This retrospective cohort study included ASD patients with coronal or sagittal imbalance who underwent thoracolumbar to pelvic fusion with ALIF or PLIF technique at the lumbosacral junction and a minimum follow-up of 2 years. The primary focus was on mechanical complications, including material failure and sacral fracture, implant-related pain, pseudarthrosis, and reoperation. Patient-specific and perioperative characteristics were also analyzed at the 2-year follow-up. The primary focus was on mechanical complications, including material failure and sacral fracture, implant-related pain, pseudarthrosis, and reoperation. Patient-specific and perioperative characteristics were also analyzed.

Results: A total of 56 patients were included, comprising 32 ALIF and 24 PLIF patients, with a mean age of 79.5 ± 6.6 years. The overall mechanical complication rate was 19.6%, including screw loosening (7.1%), rod breakage (5.4%), sacral fracture (3.6%), and screw breakage (1.8%). Pseudarthrosis and reoperation rates were 10.7% each. ALIF significantly reduced mechanical complications compared with PLIF (9.4% vs 37.5%, P = 0.011). The ALIF group also showed lower rates of pseudarthrosis, implant-related pain, and reoperation (P < 0.05). Regression analysis identified PLIF as an independent risk factor for mechanical complications (P = 0.006). Length of hospital stay, operative time, and pseudarthrosis rate were significantly associated with an increased rate of mechanical complications, but patient demographics had no significant impact.

Conclusion: Approximately 1 in 5 patients experiences mechanical complications within 2 years of ASD correction surgery. ALIF at the lumbosacral junction significantly reduces mechanical complications and pseudarthrosis compared with PLIF, resulting in lower reoperation rates. These findings suggest that ALIF should be the preferred technique for lumbosacral fusion in long-segment ASD constructs, provided there is no spondylolisthesis or severe spinal stenosis with L5 nerve root compression requiring simultaneous direct posterior decompression and fusion. This is particularly important in patients at risk for mechanical complications and pseudarthrosis, including those undergoing revision procedures.

Level of evidence: 3 - Retrospective comparative study.