The primary objective of this study is to evaluate the safety and performance of the NuVasive XLIF Decade Plate System as measured by patient-reported outcomes (PROs), radiographic outcomes, and reported complications.

This study is a prospective, single-arm, multicenter study to evaluate the safety and performance of the XLIF Decade Plate in patients undergoing a thoracic and/or lumbar interbody fusion, at one or two levels, with supplemental fixation using a lateral plate. Consecutive patients at a given site who meet all eligibility requirements will be asked to consent to participate in the study. Eligible patients include those with degenerative conditions in the thoracic and/or lumbar spine that are amenable to surgical treatment and will be screened prior to study enrollment. Once enrolled in the study, subjects will undergo XLIF surgery with lateral plating using the Decade Plate. At least 75 subjects will be enrolled and will be followed for 24 months after surgery.

Inclusion Criteria:

1. Patients who are ≥18 years of age at the time of consent

2. Planned interbody fusion surgery using the Decade Plate System in conjunction with an interbody implant to treat one or two levels in the thoracic and/or lumbar spine for

   1. degenerative disc disease
   2. spondylolisthesis
   3. scoliosis, kyphosis, lordosis
   4. spinal stenosis
   5. spondylolysis
   6. pseudoarthrosis or failed previous spine surgery

3. Able to undergo surgery based on physical exam, medical history, and surgeon judgment

4. Understands the conditions of enrollment, is willing to follow medical advice including postoperative activity restrictions per the surgeon's standard of care, and is willing to sign an informed consent form to participate in the study

Exclusion Criteria:

1. Use of posterior fixation for the scheduled surgery Note: Should the surgical plan change intraoperatively and posterior fixation is used in the case, the participant will be withdrawn from the study
2. Patient is involved in active litigation relating to the spine (worker's compensation claim is allowed if it is not contested)
3. Use of bone growth stimulators postoperatively
4. Active smoking within 6 weeks before surgery
5. Patient has known sensitivity to materials implanted
6. Systemic or local infection (latent or active) or signs of local inflammation
7. Patient has inadequate bone stock or quality, or a physical or medical condition that would prohibit beneficial surgical outcome based on surgeon judgment
8. Pregnant, or plans to become pregnant during the study
9. Patient is a prisoner
10. Patient is participating in another clinical study that would confound study data

The Enrolled Population will include all subjects who meet the criteria for enrollment, specifically, those subjects who:

• Satisfied the inclusion and exclusion criteria
• Signed the informed consent
• Underwent the surgical procedure, as defined in this protocol

Subjects not meeting any of these criteria will not be considered enrolled in the study, and therefore not included in any study population or analysis.