This study was started from Oct. 2015. This study aimed to evaluate the outcome of bracing following transforaminal lumbar interbody fusion (TLIF) in patients with degenerative lumbar spine diseases.

The inclusion criteria were age older than 18 years and undergoing TLIF for degenerative lumbar disc disease, spinal stenosis, or spondylolisthesis. Those who had spinal fracture, spinal infection, spinal tumor, and a history of previous spinal surgery; and those who were lost to follow-up or failed to complete the questionnaires were excluded.

Patients eligible for the study were selected by an independent research assistant. The study was explained, and informed consent was obtained from patients before the surgery. Using a randomization sequence, the patients were assigned to the brace or no brace group. The attending surgeons and patients were blinded before the surgery.

Patients in the brace group were instructed to wear a rigid brace (Knight-Taylor [chairback] brace) full-time for 12 weeks, except when bathing or lying in bed. Patients in the no brace group were instructed to wear a soft corset for 2 weeks, after which it was weaned off. All patients started wearing the brace or corset during their first ambulation out of bed following drainage tube removal after the surgery.

The success of interbody fusion was evaluated by computed tomography (CT) at the 6-month postoperative follow-up using the Brantigan-Steffee-Fraser (BSF) classification6. Radiographic fusion (BSF-3) was defined as bone bridging at least half of the fusion area with at least the density originally achieved at surgery. Radiographic locked pseudarthrosis (BSF-2) was indicated by lucency visible in the middle of the cage with solid bone growing into the cage from each vertebral end plate. Radiographic pseudarthrosis (BSF-1) was indicated by collapse of the construct, loss of disk height, vertebral slip, broken screws, displacement of the cage, significant resorption of the bone graft, or lucency visible around the periphery of the graft or cage.

Perioperative complications, such as wound infection, epidural hematoma, intraoperative dural tear, nerve root damage, and implant dislodgement, were recorded, as were the reoperations and medically related complications within 6 months. The implant-related complications, such as screw loosening, cage migration, or broken screws, detected using plain radiograph at each follow-up and CT scan at the latest follow-up were also recorded. Pedicle screw loosening was defined as a radiolucent zone around the screw on a CT scan at the 6-month follow-up

Statistical analysis was performed using SPSS (version 22.0, IBM Corp., Armonk, NY, USA). Categorical data were compared using chi-square or Fisher's exact test. Continuous data were compared using the independent t-test. The two-tailed significance level was set at p <0.05.

Inclusion Criteria:

• Patients underwent TLIF for degenerative lumbar disc disease, spinal stenosis, or spondylolisthesis

Exclusion Criteria:

• spinal fracture, spinal infection, spinal tumor, and a history of previous spinal surgery; and those who were lost to follow-up or failed to complete the questionnaires

Patients eligible for the study were selected by an independent research assistant. The study was explained, and informed consent was obtained from patients before the surgery. Using a randomization sequence, the patients were assigned to the brace or no brace group.