gms | German Medical Science

Objective: To evaluate the accuracy of 3D-fluoroscopy-image guided percutaneous minimally invasive pedicle screws of the thoracolumbar spine.

Method: Between January 2011 and May 2012 14 patients (11m, 3f) underwent dorsal instrumentation for tumor, infection and osteoporotic/traumatic fracture in the thoracolumbosacral spine. 117 pedicle screws (PS) (60 thoracic/ 57 lumbosacral) were implanted minimally invasively using percutaneous fixation systems (Medtronic CD Horizon Longitude, Ulrich Cosmic MIA) and 3D-fluoroscopy guided navigation (BrainLAB, VectorVision Sky). Accuracy of pedicle screw placement was assessed by postoperative CT-scans and analyzed by an independent neuroradiologist. Pedicle screws were divided into three categories: I = optimal, PS completely within the pedicle; II = suboptimal, minor pedicle breach, biomechanically stable and/or clinically asymptomatic; III = revision needed, major pedicle breach, suspected biomechanical instability and/or clinically symptomatic. Furthermore we reported intraoperative screw revisions, complications and re-operations.

Results: 12 screws (6 pats.) (total 10.3%; 9 thoracic (15%); 3 lumbar (5.3%)) needed intraoperative screw revisions after evaluation of the intraoperative control-3D-scan. No patient needed resurgery. Of the implanted PS 83.8% were classified as cat. I (total 98 PS: 54 lumbar (94.7%), 44 thoracic (73.3%)) and 15.4% as cat. II (total 18 PS: 3 lumbar (5.3%), 15 thoracic (25%)). 1 thoracic screw (0.8%) indexed cat. III was not revised because the pat. had no screw-related neurological or clinical symptoms and there was no suspicion of instability since the pat. received a multilevel stabilization overspanning 10 motion segments. Therefore 99.1% (98.3% thoracic, 100% lumbosacral) of the implanted PS showed a good accuracy (category I+II).

Conclusions: Minimally invasive percutaneous stabilization of the thoracolumbosacral spine by using 3D-fluoroscopy-guided navigation achieves a high accuracy rate, comparable to the “open method”. The number of intraoperative screw-revisions was acceptable and in our series there was no need for reoperations due screw malposition or any other complication. In our opinion percutaneous pedicle screw placement with 3D-fluoroscopy-navigation is a safe and reliable method.