Thoracic transfacet pedicle screw fixation: a new instrumentation technique

Abstract

<jats:p content-type="fine-print"><jats:italic>Object.</jats:italic> Pedicle screw instrumentation of the thoracic spine remains technically challenging. Transverse process and costotransverse screw fixation techniques have been described as alternatives to pedicle screw fixation (PSF). In this study, the authors introduce thoracic transfacet PSF and compare its experimental biomechanical results with those of standard PSF in short-term cyclic loading in cadaveric thoracic specimens.</jats:p> <jats:p content-type="fine-print"><jats:italic>Methods.</jats:italic> Specimens were tested intact for six cycles at compressive loads of 250 N offset by 1 cm along appropriate axes to induce flexion, extension, and left and right lateral bending. The specimens were then fixed with either a pedicle screw/rod construct or transfacet pedicle screws and retested in the same fashion. After this sequence, specimens were loaded until failure in flexion mode at a rate of 5 mm/minute was observed.</jats:p> <jats:p content-type="fine-print">Both fixation constructs provided significantly greater stiffnesses than that demonstrated when the specimen was intact (p &lt; 0.05, two-way analysis of variance). Additionally, the two constructs were statistically equivalent in terms of stiffness and load-to-failure values (p &lt; 0.05, two-tailed nonpaired t-test). The only difference observed was that the low midthoracic region (T7–9) was biomechanically weaker than the upper midthoracic and lower thoracic areas in flexion after the destabilization and instrumentation-augmented stabilization procedures.</jats:p> <jats:p content-type="fine-print"><jats:italic>Conclusions.</jats:italic> In selected thoracic surgical procedures, transfacet PSF may, after analysis of long-term biomechanical data, potentially become a reasonable alternative to conventional PSF.</jats:p>

Facet Joints of the Spine: Structure–Function Relationships, Problems and Treatments, and the Potential for Regeneration

“…Transfacet pedicle screws (TFPSs), placed through the facet joint extending into the pedicle, provide another alternative to the traditional pedicle screw fixation technique (Figure 3c) (128). According to biomechanical studies, both techniques are reported to have comparable strength in both thoracic and lumbar spine fixation (128,129).…”

“…Transfacet pedicle screws (TFPSs), placed through the facet joint extending into the pedicle, provide another alternative to the traditional pedicle screw fixation technique (Figure 3c) (128). According to biomechanical studies, both techniques are reported to have comparable strength in both thoracic and lumbar spine fixation (128,129). The minimally invasive nature of this technique is promising, but additional long-term data are necessary to evaluate its safety and ability to achieve solid fusion (130,131).…”

CT evaluation of upper thoracic spine for surgical application of transarticular screw placement

“…Biomechanical studies have shown that lumbar transfacet pedicle screw is biomechanically equivalent to the pedicle screw [18,19]. Akbay et al [20] used the transfacet pedicle screw in the middle and lower thoracic spine to compare its experimental biomechanical result with that of standard pedicle screw. Indeed the technique of transarticular screw fixation in our investigation is different with transfacet pedicle screw fixation.…”

Managing Design Excellence Tools During the Development of New Orthopaedic Implants

“…The Viper F2 system was found to be equivalent to the existing Viper 2 system in all ranges of motion (flexion extension, lateral bending, and axial rotation), and analysis details available in separate publications [11][12][13][14][15][16][17][18][19][20]21]. This technique is expensive, requires expertise in tissue testing, and only provides comparative in vitro performance in a model not fully representative of the real clinical environment.…”

“…The new Viper 2 system relies on directly fixing the spine using the vertebral facets via only one screw and washer per side. Simple facet screws have been used several decades ago with mixed clinical success [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Due to the popularity of minimally-invasive-surgery (MIS) in recent years, there is a renewed interest in more sophisticated MIS facet screw systems coupled with washers, expected to provide clinical performance equivalent to pedicle screws and rods, while minimizing operating room time, blood loss, cost and surgical trauma.…”