Location
Suwanee, GA
Start Date
17-4-2026 12:00 PM
End Date
17-4-2026 1:00 PM
Description
Introduction: Isthmic spondylolisthesis is caused by a pars interarticularis defect, leading to posterior tension band failure and anterior vertebral translation. This multifactorial defect is commonly associated with stress fractures and repetitive lumbar hyperextension during adolescence. It most often affects L5-S1, though other levels may be involved. While pars defects can be unilateral or bilateral, slippage typically occurs in bilateral defects. The degree of vertebral translation is classified by the Meyerding system, ranging from Grade I (< 25%) to Grade IV (>75%).
Most patients with isthmic spondylolisthesis remain asymptomatic; however, some present with chronic low back pain and radicular symptoms. Initial management is conservative including non-steroidal anti-inflammatory medications, physical therapy, and bracing. Surgical intervention is considered with persistent symptoms despite conservative treatment. Although no universal consensus exists regarding the optimal surgical approach, anterior lumbar interbody fusion (ALIF) is a common choice due to its ability to indirectly decompress foraminal stenosis, restore disc height, and improve sagittal alignment. The anterior approach permits near-total discectomy while sparing posterior structures. The need for supplemental posterior fixation remains debated.
Objectives: The primary objective of this study is to summarize the current literature evaluating the risks and benefits of supplemental posterior fixation when performing ALIF for isthmic spondylolisthesis.
Methods: A structured review was conducted of peer-reviewed spine surgery literature published within the last 15 years, examining the comparative outcome studies of ALIF with and without supplemental posterior fixation. Outcomes evaluated include fusion rates, complication rates, biomechanical findings, and functional outcomes.
Results: Surgical success for spinal procedures is often determined by pre- and post- operative measures, such as the visual analog scale (VAS) with subtypes like VAS-leg, VAS-back, and VAS-radicular. Other measures include quality of life, Oswestry Disability Index, and minimum important clinical difference. These subjective scores are often combined with objective variables including pelvic incidence, lumbar lordosis, percentage of anterior translation, presence of fusion, sagittal balance, and surgical complications.
Stand-alone ALIF relies solely on the interbody device to resist shear forces and restore anterior column stability. Current literature suggests stand-alone ALIF may provide adequate stability and acceptable fusion rates in carefully selected patients with low- grade isthmic spondylolisthesis (Meyerding I and II). These patients may also have decreased intraoperative blood loss, lower radiation exposure, reduced operative time, and shorter hospital stays.
In contrast, stand-alone ALIF in higher-grade slips is associated with increased risk of pseudarthrosis, nonunion, cage migration, and higher rates of revision surgery due to greater shear forces and segmental instability. ALIF with supplemental pedicle screw fixation demonstrates improved fusion rates, reduced device-related complications, and enhanced long-term biomechanical stability as compared to stand-alone constructs. The addition of posterior fixation appears to provide the greatest overall stability, potentially improving long-term durability.
Conclusion: Preliminary findings suggest that stand-alone ALIF may be appropriate to select patients with low-grade isthmic spondylolisthesis; while higher-grade slips appear to benefit from supplemental posterior fixation. Interpretation is limited by heterogeneous study designs, variable techniques, and absence of randomized trials. Ongoing analysis continues, with final results to be presented at the poster session.
Embargo Period
10-17-2026
Anterior lumbar interbody fusion with and without posterior fixation in isthmic spondylolisthesis
Suwanee, GA
Introduction: Isthmic spondylolisthesis is caused by a pars interarticularis defect, leading to posterior tension band failure and anterior vertebral translation. This multifactorial defect is commonly associated with stress fractures and repetitive lumbar hyperextension during adolescence. It most often affects L5-S1, though other levels may be involved. While pars defects can be unilateral or bilateral, slippage typically occurs in bilateral defects. The degree of vertebral translation is classified by the Meyerding system, ranging from Grade I (< 25%) to Grade IV (>75%).
Most patients with isthmic spondylolisthesis remain asymptomatic; however, some present with chronic low back pain and radicular symptoms. Initial management is conservative including non-steroidal anti-inflammatory medications, physical therapy, and bracing. Surgical intervention is considered with persistent symptoms despite conservative treatment. Although no universal consensus exists regarding the optimal surgical approach, anterior lumbar interbody fusion (ALIF) is a common choice due to its ability to indirectly decompress foraminal stenosis, restore disc height, and improve sagittal alignment. The anterior approach permits near-total discectomy while sparing posterior structures. The need for supplemental posterior fixation remains debated.
Objectives: The primary objective of this study is to summarize the current literature evaluating the risks and benefits of supplemental posterior fixation when performing ALIF for isthmic spondylolisthesis.
Methods: A structured review was conducted of peer-reviewed spine surgery literature published within the last 15 years, examining the comparative outcome studies of ALIF with and without supplemental posterior fixation. Outcomes evaluated include fusion rates, complication rates, biomechanical findings, and functional outcomes.
Results: Surgical success for spinal procedures is often determined by pre- and post- operative measures, such as the visual analog scale (VAS) with subtypes like VAS-leg, VAS-back, and VAS-radicular. Other measures include quality of life, Oswestry Disability Index, and minimum important clinical difference. These subjective scores are often combined with objective variables including pelvic incidence, lumbar lordosis, percentage of anterior translation, presence of fusion, sagittal balance, and surgical complications.
Stand-alone ALIF relies solely on the interbody device to resist shear forces and restore anterior column stability. Current literature suggests stand-alone ALIF may provide adequate stability and acceptable fusion rates in carefully selected patients with low- grade isthmic spondylolisthesis (Meyerding I and II). These patients may also have decreased intraoperative blood loss, lower radiation exposure, reduced operative time, and shorter hospital stays.
In contrast, stand-alone ALIF in higher-grade slips is associated with increased risk of pseudarthrosis, nonunion, cage migration, and higher rates of revision surgery due to greater shear forces and segmental instability. ALIF with supplemental pedicle screw fixation demonstrates improved fusion rates, reduced device-related complications, and enhanced long-term biomechanical stability as compared to stand-alone constructs. The addition of posterior fixation appears to provide the greatest overall stability, potentially improving long-term durability.
Conclusion: Preliminary findings suggest that stand-alone ALIF may be appropriate to select patients with low-grade isthmic spondylolisthesis; while higher-grade slips appear to benefit from supplemental posterior fixation. Interpretation is limited by heterogeneous study designs, variable techniques, and absence of randomized trials. Ongoing analysis continues, with final results to be presented at the poster session.