Lumbar Fusion With Nanotube Versus Titanium Cage

This study is a single-center, single-blind, randomized controlled superiority trial at the University of Kentucky. The study will enroll adults who are undergoing a 1 or 2 level transforaminal lumbar interbody fusion (TLIF) for degenerative disc disease.

Participants will be randomly assigned in a 1:1 ratio to receive either the Adaptix nanoPEEK cage or the Capstone PTC cage during their lumbar fusion surgery. Both cages are FDA-Approved and are used as part of the standard-of-care lumbar fusion surgery. The study is comparing the outcomes of the two cages to determine whether one results in better spinal fusion outcomes.

Participants will have follow-up visits after surgery. X-rays will be performed at follow-up visits and a CT scan will be performed at 6 months to evaluate the progress of spinal fusion and the condition of the device and graft. An independent radiologist will review the imaging. Participants will also complete questionnaires about disability, overall health, and back and leg pain. Follow-up may continue for up to 24 months after surgery.

Inclusion criteria

• Subject is scheduled to undergo 1- or 2-level TLIF with the principal investigator.
• Subject has failed nonoperative management for a minimum of 3 months prior to enrollment.
• Diagnosis is degenerative disc disease (DDD), defined as discogenic back pain with disc degeneration confirmed by history and radiographic studies, at 1 or 2 contiguous spinal levels from L2 to S1. Subjects may have up to grade 1-2 spondylolisthesis or retrolisthesis at the index level(s).
• Subject is able to provide written informed consent.
• Subject is, in the investigator's opinion, psychosocially, mentally, and physically able to comply with the protocol, required follow-up visits, and completion of required study forms.

Exclusion criteria

• Prior lumbar arthrodesis surgery at any level.
• Diagnosis of osteoporosis (T-score = -2.5) or severe osteopenia (T-score = -2.0 with fragility fracture history).
• Body mass index (BMI) greater than 40 kg/m².
• Requirement for additional bone grafting materials beyond milled local autograft bone (e.g., rhBMP-2, iliac crest autograft, allograft structural spacers).
• Active local or systemic infection.
• Known metal sensitivity or foreign body reaction to titanium or PEEK.
• Active malignancy or history of spinal malignancy.
• Known diabetes mellitus with preoperative HbA1c =8%, confirmed within 90 days of the planned surgery date. Diabetic patients with HbA1c <8% are eligible following standard preoperative medical optimization.
• Condition requiring medications known to interfere with bone healing (chronic oral or parenteral glucocorticoids, immunosuppressives, bisphosphonates initiated within 3 months of surgery, methotrexate, or similar agents).
• Inadequate tissue coverage over the operative site or open wound at the operative area.
• Pregnancy or planned pregnancy within the next 12 months, or currently lactating.
• Current involvement in litigation or receipt of Worker's Compensation related to back or leg pain.
• Current enrollment in another investigational drug or device study that could confound study data.
• History (present or past) of substance abuse that, in the investigator's opinion, would interfere with protocol adherence or follow-up completion.
• Any medical condition or extenuating circumstance that, in the opinion of the investigator, would preclude safe participation in the study.
• Subject is a prisoner.