Surgical Treatment of Developmental Dysplastic Lumbosacral Spondylolisthesis: Additional Help from an Intervertebral Distraction, Correction, and Reduction Device.

Background:  In mid- to high-grade adult dysplastic spondylolisthesis, surgeons are faced with three underlying components: angular, translational, and collapse of the disk. In extremely narrow intervertebral spaces, it is difficult to distract and lift the vertebral bodies by the pedicle screw system alone. In this prospective case control study, we analyzed the efficacy of the latest prototypes (distraction, correction, and reduction [DCR] instrument) with intervertebral application in terms of distraction, correction of segmental kyphosis, and slip reduction.

Methods:  Twelve adult patients (5 male and 7 female patients) were enrolled in this study. The average age was 42 years (range: 17-67 years) and in all cases the maneuver was documented during the surgery. The amount of slip reduction, the lumbosacral angle according to the Spinal Deformity Study Group dysplastic angle (dys-SDGG), and the disk height were measured preoperatively, intraoperatively, 3 months after surgery, and during the latest follow-up (range: 3-44 months). The relative height of the lumbosacral disk was determined in relation to the disk height in L3/L4.

Results:  Slippage ranged from 17 to 67%. Overall, the average slippage was 45% preoperatively and 4.8% after the reduction maneuver. The average ratio of the disk height was 0.3 preoperatively, 1.0 intraoperatively, and 0.9 at the latest follow-up. Two patients showed significant kyphotic changes, and these patients had an 18- and 21-degree lordotic improvement. From those who had a lumbosacral kyphosis >20 degrees, only one patient did not show any lordotic improvement. All other patients had a significant lordotic improvement. In total, the lumbosacral angle changed from 15 to 23 degrees.

Conclusion:  The application of an intervertebral distractor with a mobile thigh has a good clinical and radiologic outcome for mid- to high-grade adult dysplastic spondylolisthesis in terms of distraction, kyphosis correction, and reduction of underlying slippage. The described hardware failures and the complications were not related to the DCR device.