Advanced Materials Science in XLIF Study

This study is a prospective, non-concurrent, multicenter study to compare the clinical and
radiographic outcomes of smooth PEEK, 3D-printed titanium, and Porous PEEK interbody implants
when used with cancellous allograft chips with BMA or cellular allograft in subjects who
undergo XLIF surgery at one or two levels. To minimize selection bias, all consecutive
patients at a given site who meet eligibility requirements will be asked to consent to
participate in the study. These patients will present with degenerative conditions in the
lumbar spine that are amenable to surgical treatment and will be screened prior to study
enrollment. Once enrolled into the study, subjects will undergo their XLIF operation using
one of the 3 previously noted interbody implants based on a non-concurrent enrollment
schedule. The bone graft material used inside the interbody implant will be randomly assigned
between cancellous allograft chips with BMA or cellular allograft prior to surgery based on
surgeon investigators' equipoise for the effectiveness of both bone graft materials. Subjects
will be followed for 24 months following surgery to determine the number of study subjects
that are solidly fused at or before 24 months postoperatively.

Inclusion Criteria:

1. Male and female patients who are 18-80 years of age;

2. Planned extreme lateral interbody fusion (XLIF) procedure prior to enrollment in the
research at one or two lumbar levels for degenerative disc disease, including those
with up to Grade 2 spondylolisthesis, with one of the following interbody implants:

1. CoRoent® XL PEEK (NuVasive, Inc., San Diego, CA) interbody implant; or

2. Modulus® 3D-printed titanium (NuVasive, Inc.) interbody implant; or

3. Porous PEEK™ interbody implant (NuVasive, Inc.).

The planned XLIF procedure must include placement of bilateral posterior screw
fixation without posterior bone grafting. Direct posterior decompression at the index
XLIF levels is acceptable.

3. Preoperative coronal Cobb angle of less than 10 degrees;

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

5. Understands the conditions of enrollment and willing to sign an informed consent to
participate in the evaluation.

Exclusion Criteria:

1. Lumbar pathologies requiring additional treatment (excluding decompression) beyond the
index XLIF level(s);

2. Previous lumbar fusion surgery (note: prior decompression is not an exclusion);

3. Procedure that requires or results in the release of the anterior longitudinal
ligament or posterior osteotomy;

4. Preoperative coronal Cobb angle of greater than or equal to 10 degrees;

5. Procedures performed with interbody implants with integrated vertebral body screw(s);

6. Use of BMP or synthetic bone graft substitutes;

7. Use of nicotine products in the last six (6) months;

8. Systemic or local infection (active or latent);

9. Diseases that significantly inhibit bone healing (e.g., prior diagnosis of
osteoporosis, metabolic bone disease, uncontrolled diabetes, dialysis dependent renal
failure, symptomatic liver disease);

10. Rheumatoid arthritis or other autoimmune disease;

11. Treatment with pharmaceuticals interfering with calcium metabolism;

12. Undergoing chemotherapy or radiation treatment or chronic use of steroids (defined as
more than 6 weeks of steroid use within 12 months of surgery or anytime
postoperatively, other than episodic use or inhaled corticosteroids);

13. Use of bone stimulators postoperatively;

14. Non-ambulatory, wheelchair-bound;

15. Involvement in active litigation relating to the spine (worker's compensation claim is
allowed if it is not contested);

16. Significant general illness (e.g., HIV, active metastatic cancer of any type,
uncontrolled diabetes, dialysis dependent renal failure, symptomatic liver disease);

17. Spinal metastases or active spinal tumor malignancy;

18. Immunocompromised or is being treated with immunosuppressive agents;

19. Pregnant, or plans to become pregnant during the study;

20. Mental or physical condition that would limit the ability to comply with study
requirements;

21. Prisoners;

22. Participating in another clinical study that would confound study data.