Pedicle subtraction osteotomy in the lumbar spine: indications, technical aspects, results and complications.

Pedicle subtraction osteotomy (PSO) consists of creating posteriorly trapezoidal shape of a vertebra, usually L3 or L4, in order to recreate lordosis in the lumbar spine. It is usually indicated to treat rigid kyphotic lumbar spine associated with sagittal imbalance and due to degenerative changes or to iatrogenic flat back. PSO is technically demanding with high rates of complications and should be performed by experienced teams. We presently report our experience about PSO performed in the lumbar spine (below L1) through a series of 25 cases with a special focus on technical aspects and complications associated with the surgical procedure. Mean age was 64 ± 11 years old. PSO was performed at L4 in the majority of cases. Mean blood loss was 1,070 ± 470 ml, and mean duration of the surgery was 241 ± 44 min. VAS decreased from 7.5 ± 2 preoperatively to 3.2 ± 2.5 at 1 year, and ODI decreased from 64 ± 12 preoperatively to 32 ± 18 at 1 year, p < 0.05. Mean gain of lordosis after PSO varies from 20° to 40° and was measured to 27° ± 10° on average. Lumbar lordosis (T12-S1) was measured to 21° ± 10° preoperatively to 50° ± 11° postoperatively at 1 year, p < 0.05. A total of five major complications (20 %) were observed (two mechanical, one neurological and two infections) necessitating five reoperations. In conclusion, PSO was highly efficient to restore lumbar lordosis and correct sagittal imbalance. It was associated with a non-negligible, but acceptable rate of complications. To limit the risk of mechanical complications, we recommend fusing the adjacent disks whatever the approach (PLIF/TLIF/XLIF). Most complications can be reduced with adequate environment, informed anesthesiologists and experienced surgical team.