Comparative Accuracy of Cervical Pedicle Screws Placement using Funnel Technique and Topographic Landmarks Surgical Technique

Abstract

Introduction The aim of the study is to evaluate accuracy of cervical pedicle screws placement using funnel technique and topographic landmarks surgical technique. Materials and Methods Ten fresh frozen cervical spines (C3-C7) were used (100 pedicles, 20 pedicles per level). The average specimen age was 62.5 years (range, 51-75 years); pedicle width, sagittal angle, and transverse angle were measured on preoperative axial computed tomography (1 mm slices) for every pedicle. All the specimens were randomly divided into two groups. The pedicles (C3-C7) of experimental group were instrumented with 3.5 mm screws with the funnel technique and the control group with the topographic landmarks surgical technique. No intraoperative φλuoroscopy or radiographic control was used during any part of the entire procedure. Critical perforations (documented contact of a screw with, or an injury to, a spinal cord, nerve root, or vertebral artery) and noncritical perforations (a perforation with no critical contact) were recorded. Results In five pedicles (5%), the procedure was aborted because of a small or nonexistent pedicle medullary canal. In Group I (funnel technique), 82% of screws were placed in the pedicle correctly, seven pedicles (18%) had noncritical breaches, and two pedicles (4%) had critical perforations. In Group II (topographic landmarks surgical technique), 62.2% of screws were placed in the pedicle correctly, whereas 11 pedicles (24.4%) had noncritical perforations and 6 pedicles (13.3%) had critical perforations. Statistically significant differences were demonstrated between the two groups ( p<0.05). Conclusion Funnel technique can enhance accuracy and further improving the safety of transpedicular screw placement comparing with topographic landmarks surgical technique. Disclosure of Interest None declared References Abumi K, Itoh H, Taneichi H, Kaneda K. Transpedicular screw fixation for traumatic lesions of the middle and lower cervical spine: description of the techniques and preliminary report. J Spinal Disord 1994;7(1):19–28 Yingsakmonkol W, Karaikovic E, Gaines RW. The accuracy of pedicle screw placement in the thoracic spine using the “Funnel Technique”: part 1. A cadaveric study. J Spinal Disord Tech 2002;15(6):445–449 Abumi K, Shono Y, Ito M, Taneichi H, Kotani Y, Kaneda K. Complications of pedicle screw fixation in reconstructive surgery of the cervical spine. Spine 2000;25(8):962–969 Yukawa Y, Kato F, Ito K, et al. Placement and complications of cervical pedicle screws in 144 cervical trauma patients using pedicle axis view techniques by fluoroscope. Eur Spine J 2009;18(9):1293–1299 Karaikovic EE, Yingsakmongkol W, Gaines RW Jr. Accuracy of cervical pedicle screw placement using the funnel technique. Spine 2001;26(22):2456–2462 Chan CY, Kwan MK, Saw LB. Safety of thoracic pedicle screw application using the funnel technique in Asians: a cadaveric evaluation. Eur Spine J 2010;19(1):78–84 Ludwig SC, Kowalski JM, Edwards CC II, Heller JG. Cervical pedicle screws: comparative accuracy of two insertion techniques. Spine 2000;25(20):2675–2681