7 Facet Screw Systems



Simon P. Lalehzarian, Benjamin Khechen, Brittany E. Haws, Kaitlyn L. Cardinal, Jordan A. Guntin, and Kern Singh

7 Facet Screw Systems



7.1 Introduction


The posterior approach for facet screw fixation is described in Chapter 3 Posterior Retractor Systems. Facet screws were developed as an alternative to the standard pedicle screw fixation system. 1 By utilizing facet screws as an adjunct to minimally invasive fusion, the safety, feasibility, and overall morbidity associated with standard fixation were all theorized to substantially improve. 2 Surgical indications are presented in ▶ Table 7.1.



7.1.1 Facet Screw Components


Facet screws are similar in design to pedicle screws, with variations in body length to accommodate the different approach and point of fixation. 1 The “translaminar transfacet” and “transfacet pedicle” techniques were both developed to provide access to the facet joints for appropriate fixation (▶ Fig. 7.1). 3 Both techniques have exhibited successful restriction of facet motion; however, there are differences in the type of instrumentation and insertion angle utilized in each technique. 1 The translaminar transfacet technique utilizes longer screw lengths with the perceived benefit of increasing mechanical robustness. 2 This technique also utilizes a different angle of insertion in order to enter the contralateral lamina and end at the base of the ipsilateral transverse process, potentially increasing the strength of fixation. 3 , 4



7.1.2 Outcomes


Facet screws have exhibited exceptional outcomes when utilized as a method of spinal fixation. These instruments have been demonstrated to induce stability in multiple spinal motion planes, including flexion, extension, and rotation. 5 Additionally, translaminar facet screws have been noted to increase the stiffness of spinal motion segments and the associated interbody device. 6 , 7 , 8 These characteristics are thought to reduce the risk of cage collapse and subsidence. 8 Furthermore, by stabilizing the facet joint, facet screws are able to minimize the uncoupling of the facet that occurs from interbody device distraction. 7 , 9 This consequently provides increased stability in extension and axial rotation, which is often weakened from interbody distraction. 9 Facet screws also exhibit advantages when compared to other types of spinal instrumentation. Previous studies have determined significant reduction in rates of neurologic injury and cerebrospinal fluid leaks with facet screw fixation in comparison to pedicle screw fixation. 10 , 11 Biomechanically, facet screws often appear to be equivalent to pedicle screws in providing mechanical fixation and stability. 5 , 8 , 12











Table 7.1 Surgical indications for facet screws

Indications




  • Anterior approach spinal fusion



  • Posterior approach spinal fusion



  • Cervical procedures



  • Thoracolumbar procedures



  • Degenerative disk disease



  • Spondylolisthesis



  • Spinal fracture/dislocation



  • Spinal stenosis

Fig. 7.1 (a) Translaminar transfacet technique. (b) Transfacet pedicle technique. (c) Standard pedicle screw placement.


7.2 Facet Screw Systems





























Table 7.2 Alphatec Spine Illico® FS Facet Fixation System

Design


Composition


Titanium alloy


Design feature


Dual-lead thread design expedites screw implantation


Modular aspects and variations


Facet screw specifications


Diameter


4.5, 5 mm


Lengths


25–45 (5.0-mm increments), 35, 40 mm


Procedures


MIS TLIF, MIS posterior decompression


Radiographs unavailable





























Table 7.3 DePuy Synthes VIPER® F2 Facet Fixation System

Design


Composition


Gold and silver


Design feature


Dual-lead thread design expedites screw implantation


Modular aspects and variations


Screw diameters


5, 6 mm


Screw lengths


20–60 mm (5-mm increments)


Washer diameter


13, 16 mm


Procedures


MIS TLIF, MIS posterior decompression


Radiographs unavailable





























Table 7.4 Globus Medical ZYFUSE® Facet Fixation System

Design


Composition


Titanium alloy


Design features


Dual-lead thread design expedites screw implantation Cannulated screws are hydroxyapatite coated to promote bone growth


Modular Aspects and Variations


Facet Screw Specifications


Diameter


5, 6 mm


Lengths


30–60 mm (10-mm increments)


Procedures


MIS TLIF, MIS posterior decompression





























Table 7.5 Zimmer Biomet CONCERO™ Facet Screw System

Design


Composition


Titanium alloy


Design feature


Fixed lag length construct with dual-lead thread screw design


Modular Aspects and Variations


Screw diameter


4.5 mm


Screw lengths


25–45 mm (2.5-mm increments)


Washer diameter


11 mm


Washer height


4.75 mm


Procedures


MIS TLIF, MIS posterior decompression


No radiographs




































Table 7.6 Zimmer Biomet LDR FacetBRIDGE™ Facet Fixation System

Design


Composition


Titanium alloy


Design feature


Comes preassembled as a screw and washer construct


Modular aspects and variations


Screw diameters


4.5, 5.5 mm


Screw lengths


15, 17.5, 20–55 mm (5-mm increments)


Washer diameter


12 mm


Washer height


5.5 mm


4.5-mm-diameter model


5.5-mm-diameter model


Fenestrated screw (with washer attached) eases insertion and permits the screw to self-fill


Procedures


MIS TLIF, MIS posterior decompression

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Jan 25, 2021 | Posted by in NEUROSURGERY | Comments Off on 7 Facet Screw Systems

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