The purpose of this study is to compare outcomes of (i) surgical treatment with posterior dynamic stabilization and (ii) surgical treatment with internal fixation and fusion in patients with multilevel lumbar degenerative disk disease.

Study aims are:

1. To evaluate superiority of Surgical treatment with posterior dynamic stabilization compared to Surgical treatment with internal fixation and fusion in lumbar range of motion;
2. To compare Surgical treatment with posterior dynamic stabilization compared to Surgical treatment with internal fixation and fusion in functional outcomes as measured by change in Oswestry Disability Index;
3. To compare radiological, clinical, patient-reported and, safety outcomes between the two surgical approaches.

Inclusion Criteria:

1. Signed informed consent

2. Age between 30 and 75 years inclusive

3. Radiographic evidence of multi-level lumbar disc degeneration disease

4. Scheduled for 2- or 3-level lumbar discectomy at levels from L1 to S1 with or without dynamic stabilization or fusion

5. Preoperative ODI ≥ 30%

6. Clinical symptoms consistent with diagnosis of lumbar DDD:

   • Radicular back or lower extremity pain and/or
   • Decreased muscular strength and/or
   • Abnormal sensation

7. Failed to gain adequate symptom relief from at least one month of adequate non-operative treatment

Exclusion Criteria:

1. Cauda equina syndrome
2. Patients with other lumbar conditions that will, in the opinion of the investigator, interfere with clinical outcomes (e.g. spinal structural deformities, spinal fractures, ankylosing spondylitis, spinal tuberculosis, spinal infection, spinal tumors, symptomatic cervical spinal disease)
3. Osteoporosis defined as T-score ≤ -3.5. BMD will be measured by DEXA performed on lumbar spine
4. Systemic infection such as AIDS and active hepatitis
5. Recent history (less than 3 years) of chemical substance dependency or significant psychosocial disturbance, which may impact the outcome or study participation
6. Participation in a clinical trial of investigational drug or device within the past 30 days

Patients of The Third Medical University/Southwest Hospital with multilevel lumbar degenerative disk disease.