Lateral Lumbar Interbody Fusion (LLIF) is a common technique that allows for implantation of a large anterior column device without the need for resecting the anterior longitudinal ligament.
Previous studies have highlighted the possibility for stand-alone LLIF cages without the need for supplementary posterior instrumentation, preserving the posterior elements. LLIF as a minimally invasive approach may be beneficial, particularly for patients with comorbidities.
Here, we present radiographic and patient-reported outcomes for a cohort of patients with instability who underwent stand-alone LLIF with PSI.
Clinical outcomes included Visual Analogue Scale (VAS) and Quality of Life (QoL) scores. Radiographic outcomes were measured using segmental lordosis.
Finite Element Analysis was performed to evaluate stress and strain distributions for constructs with and without integral screw fixation.
We report results for a preliminary cohort of 6 patients. No patients required further reoperation, including for additional supplementary fixation. Segmental lordosis was maintained (no statistical difference [p>0.05]) up to 6 months post-operatively. There was a 4.8 improvement in VAS (back pain) scores and a 0.61 increase in QoL scores.
Traditional circumferential procedures involve two stages; an anterior column stage followed by repositioning the patient for pedicle rod and screw instrumentation. A stand-alone lateral approach is appealing as it eliminates the need for repositioning, reduces operating times and reduces trauma to the patient. However, there are concerns regarding the stability of stand-alone constructs.
PSI inherently allow for a higher contact surface area between strong cortical bone and the device, potentially providing more stability than generically shaped implants. Cages and plates that are one piece (integrally formed devices) combined with screw fixation may further improve stability.
Although the cohort in the present study is small, stand-alone PSI from a lateral approach are demonstrated to be a promising alternative to circumferential fusion for patients with frailty.