MagnetOs Flex Matrix Compared to Trinity Elite Mixed with Local Autograft in Patients Undergoing Up to Four-level Instrumented Posterolateral Fusion

Inclusion Criteria:

• Patient is able to read/be read, understand, and provide written informed consentand has signed the Investigational Review Board (IRB) approved informed consent.

• Male or female patient ≥ 18 years old.

• Patients with leg pain, and/or back pain requiring up to four-level instrumentedposterolateral lumbar/thoraco-lumbar fusion (T11 - S1)

• Failed conservative treatment (physical therapy, bed rest, medications, spinalinjections, manipulations, or transcutaneous electrical nerve stimulation) for aminimum period of 3 months prior to study enrollment.

Exclusion Criteria:

• Requires > four-level fusion or expected to need secondary intervention within oneyear following surgery.

• Had prior PLF fusion or attempted PLF fusion at the involved levels

• Had previous decompression at the involved levels.

• Women who are or intend to become pregnant within the next 12 months

• To treat conditions in which general bone grafting is not advisable.

• In conditions where the surgical site may be subjected to excessive impact orstresses, including those beyond the load strength of fixation hardware (e.g.,defect site stabilization is not possible).

• In case of significant vascular impairment proximal to the graft site.

• In case of severe metabolic or systemic bone disorders (e.g., osteogenesisimperfecta or Paget's Disease) that affect bone or wound healing.

• In case of acute and chronic infections in the operated area (soft tissueinfections; inflammation, bacterial bone diseases; osteomyelitis).

• When intraoperative soft tissue coverage is not planned or possible.

• Receiving treatment with medication interfering with calcium metabolism.

• Had leg pain, and/or back pain related to a benign or malignant tumor.

• Had history or presence of active malignancy.

• Has known substance abuse, psychiatric disorder, or condition which, in the opinionof the investigator, may influence the healing or ability to comply with protocolrequirements.

• Is involved in active litigation relating to his/her spinal condition.

• Has participated in an investigational study within 30 days prior to surgery forstudy devices.