[Clinical application of "funnel technique" in planting thoracic pedicle screws].

Objective: To evaluate the safety and accuracy of "funnel technique" in planting thoracic pedicle screws.

Methods: From August 2005 to March 2008, a total of 39 patients with at least one thoracic pedicle screw in T1-T10 using "funnel technique" were retrospectively reviewed. Among the patients, 27 patients were male and 14 patients were female, with a mean age of 38.5 years (ranged from 17 to 56 years). One patient was lost follow-up, and other 1 patient was dead before follow-up. The accuracy of screw placement and the complications related to thoracic pedicle screws were analyzed by postoperative CT-scans.

Results: All the patients were followed up ranging from 18 to 30 months, averaged 23.2 months. There were no vascular or viscera complications as well as iatrogenic neurologic injuries. The total number of screws was 208. There was no statistical difference between the percentage of fully contained screws at T1-T4 versus T5-T8 (P = 0.80),T5-T8 versus T9-T10 (P = 0.07), T1-T4 versus T9-T10 (P = 0.06). Twenty-seven screws (13.0%) were misplaced, 14 screws (6.7%) violated lateral cortex of pedicle, 7 screws (3.4%) medially, 5 screws (2.4%) superiorly, 1 screw (0.5%) violated lateral cortex of vertebral body. No violations occurred superiorly or anteriorly. Only 4 screws (1.9%) was a critical perforation.

Conclusion: The "funnel technique" is a simple, safe, accurate and cost-effective technique for pedicle screw placement. It provides even an entry-level surgeon with a safe way to identify and place thoracic pedicle screws.