Turkish Neurosurgery 2021 , Vol 31 , Num 5
Accuracy of Freehand Versus Modified Funnel Technique for Pedicle Screw Insertion in the Thoracic Spine
Omer Faruk KILICASLAN1,Mehmet Ali TOKGOZ2,Sevket BUTUN1,Vugar NABI1,Serdar AKALIN3
1Antalya Education and Research Hospital, Department of Orthopaedics and Traumatology, Antalya, Turkey
2Ankara Kecioren Training and Research Hospital, Department of Orthopedics and Traumatology, Ankara, Turkey
3Antalya Bilim University, Department of Orthopedics and Traumatology, Antalya, Turkey
DOI : 10.5137/1019-5149.JTN.34716-21.3 AIM: To describe a new pedicle screw insertion technique, a modification of the funnel technique, and to compare this technique with conventional freehand screw insertion regarding their accuracy and complications in the thoracic spine.

MATERIAL and METHODS: Three hundred forty-three patients who underwent a posterior spinal fusion with different etiologies were retrospectively analyzed. In 84 patients, pedicle screws were placed using the freehand technique, and in 259 patients, the modified funnel technique was used. Screw malposition was evaluated in the immediate and final follow-up in anteroposterior and lateral spinal radiographs by two independent observers. The rates of incorrect pedicle screws and complications, surgical duration, and estimated blood loss were compared between the groups.

RESULTS: A total of 6141 pedicle screws (1468 in the freehand group, 4673 in the modified funnel group) were evaluated. The rate of incorrect pedicle screws was higher in the freehand group (12.0% vs. 4.6%, p=0.001). The surgical time was shorter in the modified funnel group (190.9 ± 57.0 vs. 174.1 ± 47.6 min; p=0.017). The estimated blood loss was similar between the groups (1391.50 ± 570.01 vs. 1264.13 ± 602.29 mL; p=0.053). There were 82 intraoperative pedicle fractures but no neurologic complications in either group.

CONCLUSION: The modified funnel technique provides more accurate pedicle screw insertion in the thoracic spine in the presence of dysplastic pedicles in conjunction with axial rotation compared with the freehand technique. Furthermore, surgical time may be reduced without increasing blood loss. Keywords : Thoracic pedicle screw, Scoliosis, Freehand technique, Modified funnel technique, Ultrasonic bone curette

Corresponding author : Omer Faruk KILICASLAN, kilicaslanfaruk@hotmail.com