To study computed tomography (CT) images based on filtered back projection (FBP) reconstruction algorithm, and analyze the clinical efficacy of dexmedetomidine (Dex) combined with dezocine in thoracolumbar vertebral compression fractures patients without nerve injury during surgery, 75 patients with thoracolumbar vertebral compression fractures were divided into the experimental group (dexmedetomidine combined with dezocine intravenous injection) and the control group (dezocine intravenous injection). The anterior/middle vertebral height and kyphotic angle, assessment of thoracolumbar function (Japanese Orthopaedic Association Score) (JOA)/pain level (visual analogue scale) (VAS), onset of sensory block/palinesthesia/post-anesthesia care unit (PACU) stay/duration of anesthesia, dosage of intravenous analgesic drugs/rate of supplementary analgesics, adverse reactions, and other indicators were observed. It found that CT image was clearer and the resolution was higher after algorithm processing; after treatment, the height of anterior/middle vertebral height in the experimental group was greater than that in the control group, P < 0.05; JOA was greater than that in the control group, and VAS score was less than that in the control group, P < 0.05; the time of onset of sensory block/palinesthesia/PACU stay, the dosage of intravenous analgesic drugs/the rate of supplementary analgesic drugs, incidence of adverse reactions were less than those in the control group, and duration of anesthesia was greater than that in the control group, P < 0.05. Therefore, this drug has a significant analgesic effect on patients with thoracolumbar fracture after surgery.