Objective To evaluate the effect of anterolateral approach in treating thoracolumbar disc protrusion. Methods From May 2004 to May 2008, 11 patients with thoracolumbar disc protrusion (T10-L3) underwent discectomy, autologous il iac bone graft, and internal fixation via anterolateral approach. There were 9 males and 2 females aged 26-57 years old (average 42.8 years old). The course of disease was 1 week-11 years (average 2.7 years). Nine patients showed the lower l imbs weakness, 8 had sensory disturbance, 6 presented with lumbodorsal pain, 5 had the lower l imb pain, 4 presentedwith sphincter muscle disturbance, 3 suffered from foot drop, and 5 had a history of lower back injury. X-ray, CT, and MRI test showed that 9 cases had the single-segmental protrusion, 2 cases had double-segmental protrusion, 2 cases were accompanied with ossification of the thoracic vertebra yellow l igament, 2 cases were combined with ossification of the vertebra posterior longitudinal l igament, and 1 was compl icated with Scheuermann disease. Preoperatively, the intervertebral height was (7.2 ± 1.3) mm and JOA score was 6.4 ± 2.8. Results The time of operation was 2.5-5.5 hours (average 3.5 hours); the blood loss during operation was 500-1 200 mL (average 750 mL). During operation, intraoperative pleural tear occurred in 1 patient, peritoneal tear in 1 patient, and dural laceration in 1 patient. Repairing was performed intraoperative and preventive suction drainage was used for 3-5 days. No postoperative hydropneumothorax and cerebrospinal fluid leakage occurred. All incisions healed by first intention. No postoperative compl ications of nerve system occurred. All the patients were followed up for 1-4 years (average 2.4 years). X-ray films showed that all the patients achieved bony fusion without the occurrence breakage and loosening of titanium plate and screw 6-9 months after operation. Three cases displayed subtle scol iosis (10-15°) without influence on spinal equil ibration. The intervertebral height increased to (12.3 ± 1.5) mm 2 weeks after operation, indicating there was a significant difference compared with preoperative value (P lt; 0.05). The intervertebral height 1 year after operation when the bony fusion was reached decreased to (7.5 ± 1.2) mm, indicating there was no significant difference compared to the preoperative value (P gt; 0.05). The JOA score increased to 7.6 ± 3.2 at 1 year after operation, indicating there was a significant difference compared with preoperative value (P lt; 0.05). The symptoms and signs of all the patients were improved to various degrees after operation. According to improvement rate evaluation system proposed by Hirabayashi t al., 4 cases were graded as excellent, 6 as good, 1 as fair, and the excellent and good rate was 90.9%. Conclusion Treating thoracolumbar disc protrusion via anterolateral approach is safe and effective.