The study is a prospective non-concurrent controlled observational evaluation of short-term operative results. As such, study sites will capture perioperative (through 6-week postoperative follow-up) case data associated with 10 standard open PLIF (posterior lumbar interbody fusion) procedures. After this open experience, these same sites will capture the corresponding data from 10 subsequent cases where the MAS (Maximum Access Surgery) PLIF variant was performed. The data from both series of cases will be compiled to identify similarities and differences between the techniques.

The objective of this evaluation is to collect and compare short-term factors related to the morbidity of approach using traditional posterior-approach interbody fusion techniques and a less invasive exposure for the same procedure. Perioperative measures and early outcomes will be documented to demonstrate differences in procedural requirements, safety, and early recovery. A total of 100 subjects will be consecutively enrolled in this prospective study from as many as 8 centers. Patients who, in the surgeon investigator's opinion, require instrumented lumbar interbody fusion and have consented to PLIF surgery for their conditions will be included. The following eligibility criteria are designed to identify existing clinic patients for whom study under this protocol is considered appropriate. All subjects must meet the inclusion/exclusion criteria in order to be considered for enrollment.

Inclusion Criteria:

• Subjects must meet all inclusion criteria to be eligible for enrollment into this observational study:

  1. Indicated for posterior lumbar interbody fusion at one or two contiguous motion segments between L1 and S1;

  2. 18+ years of age at the date of written informed consent;

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

  4. Willing and able to return for post-treatment exams according to the follow-up called for in the protocol;

  5. Signed and dated informed consent form.

     Exclusion Criteria:

• Subjects presenting with any of the following will not be included in this observational study:

  1. Mental or physical condition that would limit the ability to comply with study requirements;
  2. Spine abnormality requiring treatment at more than two levels;
  3. Prior surgery at operative or adjacent level(s);
  4. Involvement in active litigation relating to the spine (worker's compensation claim is allowed if it is not contested);
  5. Significant general illness (e.g., HIV, active metastatic cancer of any type, uncontrolled diabetes, dialysis dependent renal failure, symptomatic liver disease);
  6. Participating in another clinical study that would confound study data.

Existing clinic patients