Using post-operative CT analysis the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracic (n=69) and lumbosacral (n=271) pedicle screws was assessed. All screws were placed using the Fluoro-Nav™ system (Medtronic Sofamor Danek, Memphis, TN, USA). Screw position was completely intrapedicular in 86.5%. There were no clinically significant screw misplacements. Pedicle breaches with a potential for neurological injury (> 2 mm; medial) was 0.6%. The overall pedicle screw misplacement rate in this study is less than or comparable to reported misplacement rates using other techniques. The use of computer-assisted fluoroscopy may improve the safety of pedicle screw placement.

The purpose of this prospective study is to evaluate the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracic (T) and lumbosacral (LS) pedicle screws.

The overall thoracic and lumbar pedicle screw misplacement rate in this study is less than or comparable to reported misplacement rates using other techniques.

The use of computer-assisted fluoroscopy may improve the safety of pedicle screw placement.

Postoperative computed tomographs (CT) of three hundred and forty pedicle screws were independently reviewed. All screws were placed using the Fluoro-Nav™ system (Medtronic Sofamor Danek, Memphis, TN, USA). The relative position of the screw to the pedicle was assessed and graded as follows – A- completely in; B – < 2mm breach; C – 2–4mm breach; D – > 4–6mm breach. If an osseous breach occurred, the direction of the breach was further classified.

Overall screw position was graded A in 86.5% (294/340) of screws (91.1 % (24/271) -lumbosacral and 68.1.0% (47/69)-thoracic). Forty-six pedicle breaches occurred (24 medial; 22 lateral). Thirty-five percent (16/46) of breaches were unavoidable secondary to a pedicle screw that was larger than the size of pedicle (thoracic-13). Pedicle breaches were Grade B in 11.8%, Grade C in 1.5% and Grade D in 0.3% of screws. There were no clinically significant screw misplacements. Pedicle breaches with a potential for neurological (> 2 mm; medial) or vascular injury was 0.6% and 0% respectively.

FluoroNav™ appears to be a safe and practical adjunct for the placement of thoracic and lumbosacral pedicle screws.

Funding: Medtronic-Sofamor Danek – research support

Spinal procedures relying on percutaneous pedicle cannulation (PPC) are becoming increasingly common. The accuracy of PPC using currently available two-dimensional intraoperative imaging such as conventional C-arm fluoroscopy (CF) or computer-assisted fluoroscopy (2D_Nav) has not been evaluated. Following PPC of cadaveric spines (T4-S1) using CF and 2D_Nav, by a novice and clinical expert, the number and degree of pedicle breaches was assessed by CT. Accuracy using CF or 2D_Nav was equivalent and comparable to published reports for open pedicle cannulation. However, clinical expertise was the significant determinant of improved accuracy rather than technological factors.

To assess the accuracy of percutaneous pedicle cannulation(PPC) using currently available two-dimensional intraoperative imaging (C-arm fluoroscopy (CF) or computer-assisted fluoroscopy (2D_Nav)) for two levels of clinical expertise.

Accuracy using CF or 2D_Nav was equivalent and comparable to published reports for open pedicle cannulation. Main determinant of PPC accuracy is clinical experience, rather than technological factors.

Current technology cannot replace the need for rigorous training required to gain skill in percutaneous pedicle procedures.

Using an eleven-gauge bone biopsy needle, sixty randomized pedicles(two cadavers, T4–S1) were cannulated using CF or 2D-Nav by a staff spine surgeon or a third year orthopaedic resident. Pedicles for each vertebra were paired as internal controls for technique. After insertion of the biopsy needle, a 1.5mm aluminum tube was inserted through the needle as a marker. Using fine cut CT scans the position of each tube was assessed using a predefined grading system based on tube location relative to pedicle, direction of breech, trajectory, and position in vertebral body. Minimum score was three(ideal) and maximum was fourteen(gross misplacement). There were significantly (p< 0.05) more pedicle breaches for the resident (four CF, four 2D-Nav) compared to staff (one 2D-Nav). All breaches were thoracic with no statistical difference between number of breaches using CF and 2D-Nav for either skill group. Grade of breaches for CF (8.8) and 2D-Nav (9.4) were statistically similar. Main sources of error included poor image quality, image misinterpretation and biopsy needle flexibility causing navigational maltracking.

The risk of blood transfusion in spinal fusion surgery is significant and mandates efforts to reduce ABT. This prospective study demonstrated a significant reduction in the rate of allogeneic blood transfusion (ABT) using Cell Saver (CS), Preoperative Autologus Donation (PAD), and Preoperative Erythropoietin Therapy (PET). The ABT was inversely related to the number of modalities used: 74% (n=14/19) with zero modalities; 32% (n=24/74) with one modalities; 17% (n=9/52) with two modalities; and 7% (n=2/28) with three modalities. Due to the potential amount of blood loss during spinal fusions the use of several BC techniques in combination is required to effectively reduce ABT.

The purpose of this prospective study is to assess the efficacy of current blood conservation (BC) techniques in reducing the rate of allogeneic blood transfusion (ABT) in spinal fusions.

All three current blood conservation techniques, particularly in combination, proved to be very effective in reducing the rate of ABT in elective spinal fusions.

Transfusion of allogenic blood despite its improved safety is not without risk.

From June 1999 to September 2001, transfusion and related surgical data has been prospectively collected in one hundred and seventy-three patients undergoing elective spinal fusions. The following three BC techniques were utilized: Cell Saver (CS), Preoperative Auto-logus Donation (PAD), and Preoperative Erythropoietin Therapy (PET).

The average number of fusion levels was 2.3 (range 1–5). The average estimated blood loss was 1725 milliliters (range 250–10700). Decompression was also preformed in 75% of cases. The overall ABT rate was 28% (n=49/173). The ABT was inversely related to the number of modalities used: 74% (n=14/19) with zero modalities; 32%* (n=24/74) with one modalities; 17%* (n=9/52) with two modalities; and 7%*† (n=2/28) with three modalities respectively (*statistically significant compared to zero modality group; † statistically significant compared to one modality group). The patient demographics and surgical variables were similar between the four groups. The use of CS, PAD, and PET was independently related to ABT.

The risk of blood transfusion in spinal fusion surgery is significant and mandates efforts to reduce ABT. Due to the amount of blood loss the use of several BC techniques in combination is required to effectively reduce ABT.