#269 Accuracy of Robotic Assisted Pedicle Screw Placement in Deformity and Revision Spine Surgeries

General Session: Cutting Edge Technology - Imaging Guidance

Presented by: I. Lieberman


I.H. Lieberman (1)
X. Hu (1)

(1) Texas Back Institute, Texas Health Presbyterian Hospital Plano, Scoliosis and Spine Tumor Center, Plano, TX, USA


Introduction: Placement of implants during spinal surgery is challenging especially in patients with deformity or under revision circumstances. Robotic assisted spine surgery has shown some promising results by increasing the accuracy of spinal instrumentation, reducing potential complications and reducing radiation exposure. However, the use of robotic assisted pedicle screw placement during deformity and revision surgeries has not yet been fully evaluated.

Methods: Ninety five consecutive patients who underwent robotic assisted placement of 1,085 planned pedicle screws, from June 2010 to December 2011 were classified into four different groups: patients who did not have a deformity or previous spine surgery (group 1); patients who have a deformity but no previously spine surgery (group 2); patients who had previous spine surgery but no deformity (group 3); patients who had both spinal deformity and previous spine surgery (group 4). Each attempted screw placement was classified as:

1) successfully placed using the robotic guidance;

2) malpositioned using robotic guidance;

3) robot aborted and screw placed manually;

4) screw omitted and deemed not needed at surgeon´s discretion considering the clinical circumstances.

Chi square tests and fisher´s exact test were used to analyze categorical variables (gender, age, BMI and surgery route). ANOVA test and tukey´s test were used to analyze the results of robotic assisted pedicle screw placement.

Results: There were 10 patients in group 1 (median age: 54 years), 36 patients in group 2 (median age: 38 years), 12 patients in group 3 (median age: 61 years) and 37 patients in group 4 (median age: 59 years). The patients' deformities in group 4 were less severe than group 2. More patients had minimally invasive or percutaneous surgeries in group 1 (80%) and group 3 (50%) compared with group 2 (8.3%) and group 4 (13.5%). The rate of successfully placed pedicle screws was: 96.08% in group 1, 85.82% in group 2, 89.71% in group 3 and 87.87% in group 4 (p< 0.05). The rate of malpositioned screws was 3.92% in group 1, 0.71% in group 2, 2.94% in group 3 and 0.74% in group 4 (p>0.05) with an overall malposition rate of 1.01%. There were no significant differences in the rates of manually placed and omitted screws among the four groups.

Conclusion: The published rates of pedicle screw malposition during spinal deformity surgery range from 4.2% to 15.7%. The use of robotic assisted placement of pedicle screws in deformity and revision spine surgery in this series ranged from 0.74% to 3.92% with an overall malposition rate of 1.01% which appear to be an improvement over the historical figures.

Figure 1