3D image-guided surgery for fragility fractures of the sacrum.

OBJECTIVE: Stabilizing sacral fragility fractures without radiation exposure to the surgical team. INDICATIONS: Non-displaced or minimally displaced unilateral or bilateral transalar, transforaminal or central sacral fractures in weak and osteoporotic bone. CONTRAINDICATIONS: Displaced or highly unstable sacral fractures. Patients under therapeutic anticoagulation. Patients needing fast track orthopedic surgery. SURGICAL TECHNIQUE: Prone position. Reference clamp installation on posterior iliac crest. Initial 3D scan of posterior pelvic ring. Image-guided virtual determination of 2-3 interforaminal iliosacroiliac trajectories in sacral vertebrae I and II. Lateral transgluteal mini-open approach. 3D image-guided insertion of 2-3 guide wires along planned trajectories. 3D-scan for controlling guide wire positions. Virtual determination of screw lengths. Cortical drilling and cannulated screw insertion along guide wires. Radiological documentation. FOLLOW-UP: Clinical and radiological follow-up after 12 weeks, 12 and 24 months including radiographs in anteroposterior, lateral, inlet and outlet views.
RESULTS: From October 2011 until October 2016 a total of 124 sacral fracture sites (in sacral vertebrae I and II) were treated with 120 navigated sacral screws in 52 patients (48 females, 4 males; mean age 76 ± 10 years, range 36-90 years) using 3D image guidance for screw placement. Image-guidance accuracy was 99.2% (119/120 screws correctly placed). Complications comprised revision surgery for subfascial hematoma evacuation (n = 1) and screw removal due to loosening after 12 weeks (n = 2). Four patients died before final follow-up. Mean pain visual analogue scale (VAS) decreased from 8.9 ± 1.1 (presurgery value) over 3.6 ± 1.7 (postsurgery value) to 1.8 ± 1.9 (2-year follow-up value), mean Oswestry disability index (ODI) improved from 86.2 ± 4.9% (presurgery value) over 28.5 ± 9.5% (postsurgery value) to 23.3 ± 13.7% (2-year follow-up value).