Percutaneous Screw Distraction for Anatomic Restoration: Case Series

Percutaneous pedicle screw fixation with distraction reduces morbidity after traumatic thoracolumbar burst fractures; however, there are substantial limitations, particularly for correction of kyphosis. The use of fixed-angle screws may offer improved anatomic restoration, facilitating greater postdistraction vertebral height restoration and spinal canal fragment reduction. We examined the radiographic results of distraction across fixed-angle screws immediately after surgery and in long-term follow-up.

Demographic and clinical characteristics were captured for patients with traumatic thoracolumbar fractures undergoing percutaneous pedicle screw fixation by a single surgeon. Radiographic measurements were collected at predistraction, postdistraction, and long-term follow-up time points. Paired t -tests, Student's t -tests, Mann-Whitney U tests, and χ 2 tests were used to assess data where appropriate.

The case series included 22 patients (77.3% male; mean age 42.0 ± 18.4 years). Hounsfield density consistent with osteopenia was seen in 13.6% of patients at the time of injury. Sporting injuries and motor vehicle accidents were common (both 31.8%). Most injuries occurred at L1 (45.5%). Upon long-term follow-up, the mean injured-level predistraction cross-sectional area improved from 2.1 to 2.9 cm 2 ( P < .01). Compared with the superadjacent level, the injured-level cross-sectional canal area improved by 28.6% ( P < .01). Vertebral body index also improved significantly (18.8° mean change, P < .01). The mean bisegmental Cobb angle improved by 6.2° ( P = .01), and injured vertebral body compression decreased by 22.4% ( P < .01). Significant improvement in correction was achieved with experience, with final technique yielding superior cross-sectional area ( P = .04) and compression ratios ( P = .03).

Distraction across fixed-angle percutaneous screw instrumentation systems stabilizes traumatic thoracolumbar burst fractures, corrects deformity, and decompresses the spinal canal. Further comparative research is necessary to demonstrate whether outcomes are different between percutaneous instrumentation vs open fusion for thoracolumbar trauma.