Please assess the completion status of the following clinical trial:

Trial Title: Postoperative Analgesia With Buprenorphine for Postoperative Pain Control and Quality of Life After Spinal Surgery

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: SINGLE
- Phase: PHASE4
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* adults over 20 years~* taking the lumbar spinal surgery : single-level, posterior fusion~* stay in hospital more than 2 days after operation~Exclusion Criteria:~* pregnancy or breast-feeding~* allergy or contraindication to buprenorphine~* patient with decreased lung function~* patient with taking MAO inhibitor or anticonvulsant~* patient with brain lesion, or severe liver disease~* dependence in opioid drugs~* taking muscle relaxant or tranquilizer~* patient had taken buprenorphine preoperatively~* taking strong opioids before enrolling the study~* another severe source of pain except lumbar spine~* severe cardiovascular, pulmonary, or renal compromised patients

- Gender: ALL
- Minimum Age: 20 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- Buprenorphine (Type: EXPERIMENTAL): Buprenorphine group : They will apply 3 days after the spine operation.
- Tramadol (Type: ACTIVE_COMPARATOR): Tramadol group : They will take a pill of tramadol analgesics.

Based on this trial design, predict the completion outcome and termination type (if applicable).