gms | German Medical Science

Objective: The aim of the presented study was to evaluate the accuracy of pedicle screw placements compared to conventional fluoroscopy guided surgery in various lumbar spinal diseases.

Methods: For this purpose we analyzed the data of 102 patients (42 male, 60 female, mean age 65.1 years, range 38-89 years) which received lumbar spine fusion during 2008 and 2014 at our institution. Conventional pedicle screw placement was performed percutaneously with fluoroscopy guidance. For the robotic assistance we used the SpineAssist® (Mazor Robotics, Ltd., Caesarea, Israel). For measurement of the accuracy of pedicle screws we used the criteria described by Wiesner by appearance on the postoperative CT scanning: Grade0: screw within the pedicle, grade1: screw thread breach of wall of pedicle <2mm, grade2: significant breach >2mm with no neurological compromise, grade3: complication including pedicle fracture, anterior breach with neuro-vascular compromise. Statistical tests were performed by χ²test in this study with an estimated significance of the results with p=<0.05.

Results: Robotic assisted lumbar spine fusion was performed in 43 cases (42.2%) and conventional fusion in 59 cases (57.8%). Fusion was performed for a single level disease in 84 cases (82.4%), for two levels in 11 cases (10.8%) and for a multiple level disease (3-6 levels) in 7 cases (6.9%).The most common underlying medical condition was spondylolisthesis in 83 cases (81.4%), followed by traumatic fracture in 6 cases (5.9%), metastatic disease and spondylodiscitis each in 4 cases (3.9%), osteoporotic fracture in 3 cases (2.9%) and spinal canal stenosis in 2 cases (1.9%). In total 426 pedicle screws were inserted (183 robotic, 247 conventional). The accuracy of the screw placement was graded as follows: Grade0: n=84 robotic (45.9%); n=125 conventional (50.6%), Grade1: n=82 robotic (44.8%); n=104 conventional (42.1%), Grade2: n=17 robotic (9.3%); n=17 conventional (6.9%), Grade3: n=0 robotic; n=1 conventional (0.4%).Statistical analysis revealed no difference between the two operation methods (p=0.538).

Conclusion: Statistical analysis showed no significant differences between conventional fluoroscopy guided and robotic assisted technique. The robotic assisted instrumentation can provide a helpful alternative technique especially for gaining knowledge and completing a learning curve. Further issues like duration of surgery and radiation exposure should be analyzed in prospective studies to answer the open questions.