Accuracy of Pedicle Screw Insertion Using Fluoroscopy-Based Navigation-Assisted Surgery : Computed Tomography Postoperative Assessment in 96 Consecutive Patients

OBJECTIVE: Two-dimensional fluoroscopy-based computerized navigation for the placement of pedicle screws offers the advantage of using stored patient-specific imaging data in providing real-time guidance during screw placement. The study aimed to describe the accuracy and reliability of a fluoroscopy-based navigation system for pedicle screw insertion. METHODS: A total of 477 pedicle screws were inserted in the lower back of 96 consecutive patients between October 2007 and June 2012 using fluoroscopy-based computer-assisted surgery. The accuracy of screw placement was evaluated using a sophisticated computed tomography protocol. RESULTS: Of the 477 pedicle screws, 461 (96.7%) were judged to be inserted correctly. Frank screw misplacement [16 screws (3.3%)] was observed in 15 patients. Of these, 8 were classified as minimally misplaced (4 mm). No complications, including nerve root injury, cerebrospinal fluid leakage, or internal organ injury, were observed in any of the patients. CONCLUSION: The accuracy of pedicle screw placement using a fluoroscopy-based computer navigation system was observed to be superior to that obtained with conventional techniques.

Delayed Onset of Spinal Subdural Hematoma after Vertebroplasty for Compression Fracture: A Case Report

Vertebroplasty (VP) is a well-known therapeutic modality used to treat pain associated with vertebral compression fractures. Major complications such as cord or root compression, epidural and subdural hematomas (SDH) and pulmonary emboli, occur in less than 1% of patients who undergo VP after compression fracture. Spinal SDH is an extremely rare complication that usually happens a few hours after the procedure. We report a case of spinal SDH that developed at two weeks after a successful VP. We also reviewed related literatures and discussed its possible pathogenesis.