Clinical/Radiological Outcomes Associated With CONDUIT™ Anterior Lumbar Interbody Fusion (ALIF) Cage System With Supplemental Fixation for Treatment of Lumbar Degenerative Disc Disease at One or Two Contiguous Spinal Levels From L2-S1

This will be a prospective, multi-centre study at a National Tertiary Referral Centre for spinal trauma and spinal cord injuries, serving a catchment area of 5 million people. This study will follow patients undergoing anterior lumbar interbody fusion (ALIF) procedure at the Mater Misericordiae University and Mater Private Hospitals using the CONDUIT™ ALIF Cage System. This trial seeks to evaluate the performance of this CE-marked device, and to assess outcomes in frail and non-frail patient cohorts. The CONDUIT™ ALIF Cage System are intervertebral body fusion devices intended for use for anterior lumbar interbody fusion in skeletally mature patients. The devices are 3D printed cellular titanium implants that feature 80% porous macro-, micro- and nanostructures, are designed to mimic cortical and cancellous bone, and facilitate fusion.

In spine fusion procedures, bone is encouraged to grow in order to fuse vertebrae of the spine together to relieve pain or increase stability. The likelihood of a successful fusion is thought to be influenced by multiple factors. Patient-related factors influencing fusion success include comorbidities such as osteoporosis or osteopenia, diabetes, and obesity. Factors affecting the inflammatory response, such as rheumatoid arthritis or long-term steroid use may also increase the likelihood of fusion failure. Fusion success can also be influenced by age, frailty, functional status, history of smoking or steroid use. The surgical approach may also affect fusion rate. It is thought that a posterior approach may result in higher fusion failure rates (20-30%. However, the posterior approach may be considered more appropriate for older patients with multilevel fusion, who may have a higher rate of comorbidities which affect fusion rate.

Frailty is a clinically recognizable syndrome comprised of declining physiological reserve, characterized by decreased resilience to adverse health outcomes. Fried et al have defined frailty as meeting three out of five of the following criteria: low grip strength, low energy, slow walking speed, low physical activity, unintentional weight loss. The modified 5-item frailty index (mFI-5) is another method of measuring frailty commonly used in clinical settings. It has been shown to predict the occurrence of adverse outcomes following various orthopaedic surgeries. The five comorbidities included in the mFI-5 are a history of hypertension, COPD, diabetes mellitus, congestive heart failure, and a non-independent functional status. This pilot study hypothesizes that the use of CONDUIT ALIF Cage system to treat lumbar degenerative disc disease will achieve results comparable to historical cases using SYNFIX Systems.