Anterior Column Realignment (ACR) for Focal Kyphotic Spinal Deformity Using a Lateral Transpsoas Approach and ALL Release

Study Design:Retrospective case series.Objectives:Introduce and evaluate the safety of a new technique of anterior column realignment (ACR) using a lateral transpsoas approach with release of anterior longitudinal ligament and annulus for correction of focal kyphotic deformity.Summary of Background Data:Spinal sagittal imbalance can adversely affect the long-term outcomes of patients with spinal deformity.Methods:Clinical and radiographic review of patients who underwent ACR.Results:Seventeen consecutive patients (12 females; 5 males) with a mean age of 63 years (range, 35-76 y) and a mean follow-up of 24 months (range, 12-82 mo) were identified. Fourteen of 17 (82%) had previous spine surgery and 12/17 (71%) had previous fusion. Twelve of the 17 (71%) underwent ACR for adjacent segment disease. Fifteen patients (88%) had Smith-Petersen osteotomies at the ACR level.The mean motion segment angle was 9 degrees preoperatively, which corrected to -19 degrees after ACR and to -26 degrees after posterior instrumentation. Motion segment angle was maintained at -23 degrees at the latest follow-up. The mean lumbar lordosis was -16 degrees preoperatively, which improved to -38 degrees after ACR and to -45 degrees after posterior instrumentation. Lumbar lordosis was maintained at -51 degrees at the latest follow-up. Pelvic tilt averaged 34 degrees before ACR and improved to 24 degrees after ACR and posterior instrumentation and maintained at 25 degrees at the latest follow-up. Patients with preoperative negative T1 spinopelvic inclination (T1SPI) corrected from -6 to -2 degrees and those with 0 or positive T1SPI corrected from 5 to -3 degrees after ACR at the latest follow-up.Eight patients (47%) had 10 complications. Four complications occurred after ACR. Two of 4 were neurological (1 persistent weakness) and 1 was vascular injury during anterior plate removal.Conclusion:Compared with posterior-based techniques, our preliminary results of ACR showed similar correction capacity and similar rate of morbidities for the treatment of focal kyphotic spinal deformity. Careful case selection, attention to the details of the technique, and enough experience are prudent elements for a desirable outcome.