Introduction: Spinopelvic parameters related to sagittal balance have become increasinglyimportantamong spine surgeons due to their correlation with patient satisfaction rates. Objective: The goal of this study was to evaluate changes in spinal sagittal balance after lumbar spine surgery using PLIF, the posterior lumbar interbody fusion technique. Methods: The sample consisted of adult patients with degenerative spinal disease submitted to posterior lumbar arthrodesis. Patients between 18 and 70 years of agewho underwent surgeryfrom 2015 to 2017 were included in the study and divided into short (1 level) and long arthrodesis (2 to 4 levels) groups. Radiographic analysis of the spinopelvic parameters, measured before and after lumbar arthrodesis, was conducted using the SURGIMAP software. Then we evaluated the variation between pre- and postoperative measurements and performed correlation and linear regression analyses between the parameters. Results: The sample was composed of 80 patients (48 men). The mean age was lower in the short arthrodesis group than in the long arthrodesis group (52.67 ± 9.66 years versus 59.37 ± 9.30 years, respectively; p<0.0025). Significant variations in lumbar lordosis, pelvic tilt, sagittal vertical axis, T1 pelvic angle, and pelvic incidence minus lumbar lordosis were found in both short and long arthrodesis groups. The variation was significantly larger in the long than in the short arthrodesis group. Conclusion: In adult degenerative spine disease, short and long arthrodesis of the lumbar spine by PLIF allows correction of the spinopelvic parameters. Level of evidence III; Retrospective, comparative study.

Objective To evaluate the results after multiple posterior vertebral column resection (PVCR) in patients with severe kyphoscoliosis secondary to neurofibromatosis type 1 (NF-1). Methods Retrospective study of 4 adult male patients, mean age of 26.5 years, with severe rigid deformity, mean kyphosis of 122º and scoliosis of 88º, through clinical analysis and complementary exams. Results The mean postoperative follow-up was 27 months. Three vertebrae were resected on average. Interbody consolidation of arthrodesis was confirmed by CT in all cases. The correction rates of sagittal and coronal deformities were 54.09% and 70.45%, respectively. Prior to surgery, all patients were neurologically intact and as a post-surgical complication one patient had motor deficit (ASIA D) and pneumothorax also occurred in two patients. Conclusions The correction of severe kyphoscoliosis in adult patients with NF-1 is technically demanding and is not free of major complications. However, in view of the limited possibility of correction of these deformities, multiple-level PVCR has proved to be a safe and effective technique. Level of evidence IV; Case Series.