Post Marketing Study of MagnetOs Easypack Putty Standalone Compared to Demineralized Bone Matrix or Fibers Mixed With Autograft in Patients Undergoing Posterolateral Lumbar Fusion

Inclusion Criteria:

* Patient is able to read/be read, understand, and provide written informed consent and has signed the Institutional Review Board (IRB) approved informed consent.
* Male or female patient ≥ 18 years old.
* Patients with segmental mechanical spinal instability requiring arthrodesis surgery.

Instability can be either caused by degenerative disc disease or by traumatic injury to the spinal column. Patient requiring a maximum of two-level instrumented posterolateral lumbar/thoraco-lumbar fusion (T11 - S1) will be enrolled. Mechanical instability is defined by the presence of one or more of the following:

1. instability (angulation ≥ 5 degrees or translation ≥ 3 mm on flexion/extension radiographs),
2. decreased disc height by \> 2 mm, but dependent upon the spinal level
3. Grade II or more listhesis
4. TLICS equal or greater than 5
5. Unstable burst fracture

   * Failed conservative treatment (physical therapy, bed rest, medications, spinal injections, manipulations, or transcutaneous electrical nerve stimulation) for a minimum period of 3 months prior to study enrollment (if the patient undergoes elective surgery). Patients who have spinal instability (as defined above in inclusion criteria number three), caused by acute trauma requiring urgent surgical treatment are excluded from this criterion.

Exclusion Criteria:

* Requires \> two-level fusion or expected to need secondary intervention within one year 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 or stresses, 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., osteogenesis imperfecta, history of or active Pott's disease, stage \>4 renal disease or Paget's Disease) that affect bone or wound healing.
* In case of acute and chronic infections in the operated area (soft tissue infections; inflammation, bacterial bone diseases; osteomyelitis).
* When intraoperative soft tissue coverage is not planned or possible.
* Receiving treatment with medication interfering with calcium metabolism.
* Has degenerative disc disease (DDD) related to a benign or malignant tumor.
* Has history or presence of active malignancy.
* Has known substance abuse, psychiatric disorder, or a condition which, in the opinion of the investigator, may influence the healing or ability to comply with protocol requirements.
* Is involved in active litigation relating to his/her spinal condition.
* Has participated in an investigational study within 30 days prior to surgery for study devices.