Accuracy of Cervical Pedicle Screw Placement Using the Funnel Technique

Karaikovic, Eldin E.; Yingsakmongkol, Wicharn; Gaines, Robert W.

doi:10.1097/00007632-200111150-00012

Cited by 124 publications

(122 citation statements)

References 22 publications

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“…Fixation with pedicle screws is particularly useful for cervical spine stabilisation, as it enables application of a distraction force to the injured cervical spinal segment. [20][21][22][23][24][25][26] In our study, there was no discontinuity of the posterior vertebral body (on magnetic resonance imaging), indicating that ligamentous continuity of the injured disc level was preserved, and no patient experienced postoperative neurological deterioration. Cervical transpedicular fixation can safely reduce disc herniation and stabilise the cervical spine in one stage, precluding the need for anterior decompression.…”

Section: Discussionmentioning

confidence: 84%

Cervical Transpedicular Fixation Aided by Biplanar Flouroscopy

Kotıl¹,

Sengoz²,

Savas³

2011

J Orthop Surg (Hong Kong)

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purpose. To evaluate the accuracy of fluoroscopyassisted cervical transpedicular fixation in different pathologies. Methods. 28 men and 17 women aged 34 to 65 (mean, 41) years underwent 210 one-stage cervical transpedicular fixations. The indications were trauma (n=35), degenerative disease leading to cervical spondylotic myelopathy (n=4), tumours (n=4), and Pott's disease (n=2). Regarding the 35 trauma patients, fractures were at C5-C6 (n=22), C4-C5 (n=8), and C3-C5 (n=5); 16 of them had dislocated vertebrae, of whom 13 had cervical disc herniation. Two of the patients with degenerative disease underwent additional laminectomy. Both anterior and posterior surgeries were performed for the 2 of the patients with tumours; all other patients underwent posterior surgery only. The length, diameters, and frontal, sagittal, and longitudinal angles of all pedicle screws were calculated. The dominant vertebral artery was detected using 2011;19(3):326-30 Doppler ultrasonography. Biplanar fluoroscopy was also used. Postoperatively, patients were allowed to mobilise at day 1; a collar was not used. The position of the pedicle screws was graded. results. The mean operating time was 105 (range, 90-155) minutes. The mean follow-up period was 26 (range, 17-34) months. Of the 210 pedicles fixed, 192 (91%) were at the correct screw position (grade I), 16 (8%) were at an acceptable position (grade II), and 2 (1%) were completely perforated but without morbidity (grade III). The overall perforation rate was 9%. There were no neurovascular injuries or instrumentation-associated complications (failure of implant components, screw loosening, or lucent zone formation around the pedicle screws). The fusion rate was 100%. conclusion. Cervical transpedicular fixation provides strong stabilisation. With the aid of biplanar fluoroscopy, the risk of pedicle perforation was about 8%, but no neurovascular injury was ensued.

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Section: Discussionmentioning

confidence: 84%

Cervical Transpedicular Fixation Aided by Biplanar Flouroscopy

Kotıl¹,

Sengoz²,

Savas³

2011

J Orthop Surg (Hong Kong)

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“…Irrespective of all of the favorable properties of pCPSs, investigators have called attention to the liberal use of pCPSs because of the possibility of iatrogenic neurovascular injuries [19]. Although placement of pCPSs poses a potential risk to nearby neurovascular structures, standards are established, and several studies have demonstrated a significantly decreased risk for complications through the implementation of navigation tools and surgical training, which increases accuracy [4,21,22].…”

Section: Discussionmentioning

confidence: 99%

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

et al. 2012

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Study purpose With increasing usage within challenging biomechanical constructs, failures of C2 posterior cervical pedicle screws (C2-pCPSs) will occur. The purpose of the study was therefore to investigate the biomechanical characteristics of two revision techniques after the failure of C2-pCPSs. Materials and methods Twelve human C2 vertebrae were tested in vitro in a biomechanical study to compare two strategies for revision screws after failure of C2-pCPSs. C2 pedicles were instrumented using unicortical 3.5-mm CPS bilaterally (Synapse/Synthes, Switzerland). Insertion accuracy was verified by fluoroscopy. C2 vertebrae were potted and fixed in an electromechanical testing machine with the screw axis coaxial to the pullout direction. Pullout testing was conducted with load and displacement data taken continuously. The peak load to failure was measured in newtons (N) and is reported as the pullout resistance (POR). After pullout, two revision strategies were tested in each vertebra. In Group-1, revision was performed with 4.0-mm C2-pCPSs. In Group-2, revision was performed with C2-pedicle bone-plastic combined with the use of a 4-mm C2-pCPSs. For the statistical analysis, the POR between screws was compared using absolute values (N) and the POR of the revision techniques normalized to that of the primary procedures (%). Results The POR of primary 3.5-mm CPSs was 1,140.5 ± 539.6 N for Group-1 and 1,007.7 ± 362.5 N for Group-2; the difference was not significant. In the revision setting, the POR in Group-1 was 705.8 ± 449.1 N, representing a reduction of 38.1 ± 32.9 % compared with that of primary screw fixation. For Group-2, the POR was 875.3 ± 367.9 N, representing a reduction of 13.1 ± 23.4 %. A statistical analysis showed a significantly higher POR for Group-2 compared with Group-1 (p = 0.02). Although the statistics showed a significantly reduced POR for both revision strategies compared with primary fixation (p \ 0.001/ p = 0.001), the loss of POR (in %) in Group-1 was significantly higher compared with the loss in Group-2 (p = 0.04). Conclusions Using a larger-diameter screw combined with the application of a pedicle bone-plastic, the POR can be significantly increased compared with the use of only an increased screw diameter.

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“…However, lateral mass screws are not without their risks [25], and pedicle screw placement in the lumbar spine has a documented perforation rate of over 5% [8] despite the larger diameter of the pedicles. Documented cervical pedicle perforation rates vary from 4 to 87.5% [2,4,5,11,16,17,24,29], with cadaveric studies reporting a higher incidence than comparable clinical experiments. However, throughout the literature there is a distinction between 'minor' and 'critical' perforation rates, with the former unlikely to be of clinical significance.…”

Section: Discussionmentioning

confidence: 99%

The ipsilateral lamina–pedicle angle: can it be used to guide pedicle screw placement in the sub-axial cervical spine?

et al. 2009

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Pedicle screws in the sub-axial spine are infrequently used because of concerns over their safety and difficulty in placement, despite their superior pullout strength. In the sub-axial cervical vertebrae, we have observed that the lamina appears to project at right angles to the ipsilateral pedicle axis. The aim of this investigation was to confirm the lamina orientation as a reliable landmark for pedicle screw placement. 80 digital cervical spine CT were analysed. The angle formed by the ipsilateral outer lamina cortex to the pedicle axis was recorded. A total of 398 vertebrae were analysed from patients with a mean age of 39.5 years (range 18-78). Average axial lamina-pedicle angle ranged from 96.6°at C3 to 87.2°at C7 in males, and from 95.6°to 87.5°in females. The angle formed by the posterior cortex of the lamina and the ipsilateral pedicle shows a high level of consistency for subaxial cervical vertebrae ranging from 96°at C3 to 87°at C7. Although the angle is not exactly 90°at all levels as hypothesised, the orientation of the lamina, nevertheless, forms a useful reference plane for insertion of pedicle screws in the sub-axial cervical spine.

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Accuracy of Cervical Pedicle Screw Placement Using the Funnel Technique

Abstract: Axial computed tomography is necessary for the preoperative planning. Because of the small diameter and steep angulation of cervical pedicles, every spine surgeon who intends to use pedicle screws should first master the technique on cadavers.

Cited by 124 publications

References 22 publications

Cervical Transpedicular Fixation Aided by Biplanar Flouroscopy

Cervical Transpedicular Fixation Aided by Biplanar Flouroscopy

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

The ipsilateral lamina–pedicle angle: can it be used to guide pedicle screw placement in the sub-axial cervical spine?

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