Objective:To investigate the effect of middle-column preserved pedicle subtraction closing-opening wedge osteotomy for the treatment of old thoracolumbar compression fractures combined with kyphosis deformity.Methods:A retrospective case series study was performed to analyze data of 27 patients with old thoracolumbar compression fractures combined with kyphosis deformity admitted in Taizhou Hospital from January 2010 to January 2017. There were 10 males and 17 females, with age range of 45-75 years (mean, 61.7 years). The injured segments and osteotomy segments included T 11 in 5 patients, T 12 in 10, L 1in 8 and L 2 in 4. Time from initial fracture to surgery was 9-120 months (mean, 23.2 months). According to the American Spinal Injury Association (ASIA) classification, neurological impairment symptoms were detected in 9 patients, including grade C in 1 and grade D in 8. All patients underwent one-level middle-column preserved pedicle subtraction osteotomy. Operation time, blood loss, and perioperative complications were recorded. Before operation, at 3 months after operation and at latest follow-up, kyphosis Cobb angle, sagittal vertical axis (SVA) and height of anterior column (AC) as well as posterior column (PC) were measured. Visual analogue scale (VAS) and Oswestry disability index (ODI) score were used to evaluate the clinical efficacy. American Spinal Injury Association (ASIA) score was used to assess neurological function. Results:All patients were followed up for average 18.1 months (range, 12-34 months). Operation time was (155.2±35.4)minutes (range, 130-250 minutes). Blood loss was (338.1±101.4)ml (range, 150-550 ml). No serious neurological or vascular complications occurred during perioperative period. Kyphosis Cobb angle was (6.0±3.1)° at postoperative 3 months compared to preoperative (46.5±8.5)°( P<0.05), and showed no significant loss at latest follow-up [(7.9±3.8)°] ( P>0.05). SVA was improved significantly from preoperative [42.7(25.5, 78.2)]mm to [5.5(1.2, 7.3)]mm at postoperative 3 months ( P<0.05). AC height was increased by average 16.3 mm at postoperative 3 months compared to the preoperative level ( P<0.05), with no significant change in PC height ( P>0.05). There was no significant difference in SVA, AC height and PC height at postoperative 3 months and latest follow-up ( P>0.05). There were significant differences in VAS [(1.7±0.8)points, (2.3±1.4)points] and ODI (17.3±7.5, 19.4±4.3) at postoperative 3 months and at latest follow-up compared to these before operation [(7.7±1.3)points, 61.4±6.2] ( P<0.05), with no significant differences in VAS and ODI at postoperative 3 months and latest follow-up ( P>0.05). No implant failure was noted during follow-up. The osteotomy surface was fused in all patients at postoperative 6 months. At latest follow-up, ASIA grade was improved from grade C to grade D in 1 patient and from grade D to grade E in 8 patients. Conclusion:Middle-column preserved pedicle subtraction closing-opening wedge osteotomy can effectively correct old thoracolumbar fractures with kyphosis, relieve pain and improve nerve function.