Constructs Incorporating Intralaminar C2 Screws Provide Rigid Stability for Atlantoaxial Fixation

Gorek, J E; Acaroğlu, Emre; Berven, Sigurd; Yousef, Ahad; Puttlitz, Christian M.

doi:10.1097/01.brs.0000167827.84020.49

Cited by 164 publications

(74 citation statements)

References 19 publications

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“…With at least 0.5 mm tolerance bilaterally, a pedicle or laminar screw of 3.5-mm diameter can be placed safely by experienced hands. Furthermore, a trajectory of laminar screw placement with slight penetration of the dorsal cortex had been recommended by several authors [2,7]. For a patient with a relatively thin C2 laminar, this method has the benefit of placement with great ease, without the concern of penetration into the spinal canal.…”

Section: Discussionmentioning

confidence: 99%

“…In 2004, Wright et al [19] reported a new technique involving bilateral C2 laminar screws, which reduces the threat to the vertebral artery. Biomechanically, the intralaminar screw constructs were shown to provide equivalent stability to the pedicle screw constructs [7]. Similarly, Lapsiwala et al [10] also found that C2 translaminar screws provide equal structural stiffness as compared with transarticular screws and C2 pedicle screws.…”

Section: Introductionmentioning

confidence: 96%

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Pedicle versus laminar screws: what provides more suitable C2 fixation in congenital C2–3 fusion patients?

Wang

Passias

et al. 2010

Eur Spine J

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Patients with Klippel-Feil syndrome (KFS) have congenital fusions of at least 1 cervical motion segment, and often present with compensatory hypermobility or symptomatic stenosis of the cranio-vertebral junction which requires occipitocervical reconstruction and fusion. One subgroup of KFS patients in which this is particularly common is those with isolated C2-3 congenital fusion (C2-3 CF). The anatomic suitability for C2 pedicle and laminar screw placement had been analyzed in the general adult population, and guidelines for their techniques had been established. However, the feasibility and safety of the two techniques in KFS patients with congenital C2-3 fusion has not been reported. This radiographic study was performed to evaluate the feasibility of these two widely used methods in such patients. We recruited 108 patients with atlantoaxial dislocation and reconstructed CTs were performed. Among them, 53 had C2-C3 congenital fusion diagnosed as KFS and 55 had normal cervical segmentation (NCS). The maximum possible diameters and length were measured along the ideal screw trajectories. Both of mean diameters and lengths of the C2 laminar screw trajectory in the C2-3 CF group were significantly larger than that in NCS. Mean diameters of the C2 pedicle screw trajectory in this group were significantly smaller than that in NCS group, however, C2-3 CF patients had longer pedicle paths than NCS. In the C2-3 CF group, all 53 cases had suitable trajectory for C2 laminar screw, while 21 (39.6%) had a pedicle diameter less than 4.5 mm. In the NCS group, 5 cases (9.1%) had a pedicle diameter less than 4.5 mm. All 108 cases had sufficient diameters for C2 laminar screw placement. Klippel-Feil patients with C2-3 CF are good candidates for the technique of C2 laminar screw. Preoperative radiography should be carefully evaluated and the option of C2 fixation be determined with a thorough consideration in these patients.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Pedicle versus laminar screws: what provides more suitable C2 fixation in congenital C2–3 fusion patients?

Wang

Passias

et al. 2010

Eur Spine J

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“…Biomechanical stability of this fixation technique has recently been evaluated by Gorek et al [12], who found intralaminar screw constructs to be biomechanically equivalent to the Harms construct, and by extrapolation to the Magerl-Gallie construct for atlantoaxial fixation. In a similar study, Lapsiwala et al [13] have reported on a cadaveric biomechanical study comparing intralaminar to pedicle and transarticular screws for C1-C2 fixation.…”

Section: Discussionmentioning

confidence: 99%

Clinical application of C2 laminar screw technique

Feng

et al. 2010

Eur Spine J

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C2 laminar screws have become an increasingly used alternative method to C2 pedicle screw fixation. However, the outcome of this technique has not been thoroughly investigated. A total of 35 cases with upper cervical spinal instability undergoing C2 laminar screw fixation were reviewed. All cases had symptoms of atlantoaxial instability, such as craniocervical junction pain, and were fixed with the Vertex cervical internal fixation system. A total of 68 screws were placed and hybrid constructs (a C2 translaminar screw combined with a C2 pars screw) were incorporated in two patients. In this series, there were no intraoperative complications and no cases of neurological worsening or vascular injury from hardware placement. Computed tomographic scans demonstrated a partial dorsal laminar breach in ten patients. None of these resulted in neurological symptoms. None of the patients was found to have a breach of the ventral laminar cortex. All the C2 laminar screws fixations were performed successfully. There was no instability seen on the films with no evidence of hardware failure or screw loosening during the follow-up period in all patients. In conclusion, C2 laminar screw technique is straightforward and easily adopted; it can efficiently and reliably restore upper cervical stability. It is an alternative method to C2 pedicle screw fixation, especially in patients with unilateral occlusion of vertebral artery and pedicle deformity of C2.

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“…Compared to transarticular screw (Jeanneret and Magerl) [9] and pedicle screw techniques, this method can provide similar stability to the atlantoaxial complex [5,12,13], which is considered to be simpler and safer due to the less intraoperative exposure and minimal risk of vertebral artery injury [2,3,8,15,24]. Subsequent morphological studies reported the applicability of this technique in different populations and showed that this method could be applied safely in most of the specimens they studied [2,7,11,19,22].…”

Section: Introductionmentioning

confidence: 99%

Morphometric trajectory analysis for the C2 crossing laminar screw technique

et al. 2010

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This paper reports a morphometric study of the C2 laminae to provide quantitative anatomical data for safe crossing laminar screw placement. A valid trajectory is essential for C2 crossing laminar screw placement. Although several clinical technique notes and modifications to define a safe screw trajectory have been introduced in the recent years, no morphometric analysis has been performed to confirm the accuracy of screw trajectory using this technique. In this study, morphometric analysis was performed on 100 Korean C2 three-dimensional reconstruction CT images. The reconstructive C2 vertebrae from the post-edge of the spinal canal to the spinal process were divided into several zones, 1 mm each. Each zone was chosen as the entry point to imitate a crossing laminar screw (3.5 mm diameter) placement. In each 1-mm zoned trajectory, the screw pass ratio (PR), safe screw angle range (SAR) and maximum screw length (MSL) were measured and compared with the data from the other zoned trajectories. The zone '5-6 mm posterior to the post-edge of the spinal canal' was found to be a more feasible and safer entry point for guiding a crossing laminar screw placement than the other zones because this zone could provide a trajectory with maximal PR (85%), SAR (9.57 ± 4.368) and a larger MSL (21.74 ± 2.44 mm) than the other areas. The recommended safe screw angle in the axial plane is 49.68 ± 4.94 to 59.19 ± 4.708. However, the screw angle can vary considerably according to the individual variance. A preoperative evaluation of the screw trajectory is essential for safe screw placement using this technique.

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Constructs Incorporating Intralaminar C2 Screws Provide Rigid Stability for Atlantoaxial Fixation

Cited by 164 publications

References 19 publications

Pedicle versus laminar screws: what provides more suitable C2 fixation in congenital C2–3 fusion patients?

Pedicle versus laminar screws: what provides more suitable C2 fixation in congenital C2–3 fusion patients?

Clinical application of C2 laminar screw technique

Morphometric trajectory analysis for the C2 crossing laminar screw technique

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