We undertook a retrospective study investigating the accuracy and safety of percutaneous pedicle screws placed under fluoroscopic guidance in the lumbosacral junction and lumbar spine. The CT scans of patients were chosen from two centres: European patients from University Medical Center Hamburg-Eppendorf, Germany, and Asian patients from the University of Malaya, Malaysia. Screw perforations were classified into grades 0, 1, 2 and 3. A total of 880 percutaneous pedicle screws from 203 patients were analysed: 614 screws from 144 European patients and 266 screws from 59 Asian patients. The mean age of the patients was 58.8 years (16 to 91) and there were 103 men and 100 women. The total rate of perforation was 9.9% (87 screws) with 7.4% grade 1, 2.0% grade 2 and 0.5% grade 3 perforations. The rate of perforation in Europeans was 10.4% and in Asians was 8.6%, with no significant difference between the two (p = 0.42). The rate of perforation was the highest in S1 (19.4%) followed by L5 (14.9%). The accuracy and safety of percutaneous pedicle screw placement are comparable to those cited in the literature for the open method of pedicle screw placement. Greater caution must be taken during the insertion of L5 and S1 percutaneous pedicle screws owing to their more angulated pedicles, the anatomical variations in their vertebral bodies and the morphology of the spinal canal at this location.

Cite this article: Bone Joint J 2015; 97-B:1111–17.

Summary Statement

From a mechanical point of view, the clinical use of pedicle screws in the atlas is a promising alternative to lateral mass screws due to an increased biomechanical fixation.

Introduction: It is commonly admitted that for any joint fracture in the human body, a perfect anatomical reduction before stabilization is the only manner to biomechanically restore a joint and avoid late complications by early mobilization allowance. But, there is no evidence of anatomical fracture reduction when using vertebroplasty or balloon kyphoplasty in case of traumatic vertebral compression fractures (VCF).

Materials & Methods: A new procedure was proposed using titanium permanent vertebral cranio-caudal expandable implants (VCCEI) in combination with PMMA cementoplasty. The procedure has consisted in two steps: first, reduce the fractured vertebral body under fluoroscopic guidance by expanding the implants and second, stabilize the vertebra in its reduced position using PMMA cement injection. The implants ability to reduce the fractured endplates was assessed within a prospective international clinical study enrolling 37 patients (Mean age: 53yo, 18F/19M). 40 VCF (34 single level and 3 double levels) were included in this series. Mean fracture age was 11 days at the time of surgery. To evaluate the anatomical restoration, a new 3D measurement method was developed using millimetric CT scans 3D reconstructions. Morphologic parameters such as vertebral kyphosis angle and endplate surface restoration were calculated and clinical parameters were monitored (VAS score monitoring, hospital stay duration).

Results: First results are showing that the VCCEI is able to reduce the fractured vertebra whatever is the type of fracture providing that it is still mobile. Both vertebral kyphosis angle reduction and endplate surface restoration were achieved: up to 92% improvement for vertebral kyphosis and up to 10,8mm height increase in the anterior part of a fractured endplate. Posterior wall displacements were negligible. Neither antepulsion nor retropulsion of broken fragments were observed. No postoperative complication was reported but minor asymptomatic cement leakages. Pain was significantly reduced at the same time and hospital stay was comparable to

Conclusion: This new procedure has demonstrated its clinical and radiological efficacy in achieving anatomical reduction of VCF as well as relieving pain. The unique design of this VCCEI allows the surgeon to apply controlled cranio-caudal forces to reduce the fractured vertebra according to the fracture type and thus optimize the way the fracture will be reduced. Providing that the technique allows for a good control of the way the reduction is performed, there is a new possibility to treat VCF as they should deserve.