Previous reports have emphasized the importance of neural decompression through either an anterior or posterior approach when reconstruction surgery is performed for neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine. However, the contribution of these decompression procedures to neurological recovery has not been fully established. In the present study, we investigated 14 consecutive patients who had incomplete neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine and underwent posterior instrumented fusion without neural decompression. They were radiographically and neurologically assessed during an average follow-up period of 25 months. The mean local kyphosis angle was 14.6 degrees at flexion and 4.1 degrees at extension preoperatively, indicating marked instability at the collapsed vertebrae. The mean spinal canal occupation by bone fragments was 21%. After surgery, solid bony fusion was obtained in all patients. The mean local kyphosis angle became 5.8 degrees immediately after surgery and 9.9 degrees at the final follow-up. There was no implant dislodgement, and no additional surgery was required. In all patients, back pain was relieved, and neurological improvement was obtained by at least one modified Frankel grade. The present series demonstrate that the posterior instrumented fusion without neural decompression for incomplete neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine can provide neurological improvement and relief of back pain without major complications. We suggest that neural decompression is not essential for the treatment of neurological impairment due to osteoporotic vertebral collapse with dynamic mobility.