Anatomical and technical factors associated with superior facet joint violation in lumbar fusion

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>The aim of this study was to evaluate the anatomical and surgical risk factors for screw-related facet joint violation at the superior level in lumbar fusion.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>The authors conducted a retrospective review of a consecutive series of posterior lumbar instrumented fusions performed by a single surgeon. Inclusion criteria were primary lumbar fusion of 1 or 2 levels for degenerative disorders. The following variables were analyzed as possible risk factors: surgical technique (percutaneous vs open screw placement), depth of surgical field, degree of anterior slippage of the superior level, pedicle and facet angle, and facet degeneration of the superior level. Postoperative CT scans were evaluated by 2 independent reviewers. Axial, sagittal, and coronal views were reviewed. Pedicle screws were graded as intra-articular if they clearly interposed between the superior and inferior facet joints of the superior level. Multivariate logistic regression analyses were conducted to assess the factors associated with this complication.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>One hundred thirty-one patients were included. Interobserver reliability for facet joint violation assessment was high (κ = 0.789). The incidence of superior facet joint violation was 12.59% per top-level screw (33 of 262 proximal screws). The rate of facet violation was 28.0% in the percutaneous technique group (14 of 50 patients) and 12.3% in the open surgery group (10 of 81 patients) (OR 2.26, 95% CI 1.09–4.21; p = 0.024). In multivariate logistic regression analysis, independent predictors of facet violation were percutaneous screw placement (adjusted OR 3.31, 95% CI 1.42–7.73; p = 0.006), right-side pedicle screw (adjusted OR 3.14, 95% CI 1.29–7.63; p = 0.011), and facet angle &gt; 45° (adjusted OR 10.95, 95% CI 4.64–25.84; p &lt; 0.0001).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>The incidence of facet joint violation was higher in percutaneous minimally invasive than in open technique for posterior lumbar spine surgery. Also, coronal orientation of the facet joint is a significant risk factor independent of the surgical technique.</jats:p></jats:sec>

Parafusos pediculares e violação facetária – A importância do ângulo entre a faceta e o parafuso

“…Despite the identification of techniques that can bring more risks of violation, another point is to identify structures and parameters that can serve as a reference for location, and, theoretically, for the reduction of facet violation. 6,17,22 Among the factors pointed out as having a relation to the facet violation, Jia et al 23 showed that the lower the location, the higher the rate of facet violation, similar to the findings of Teles et al, 6 who reported 100% of facet violations at levels L4 and L5. These results are different from those indicated by our study, which identified the thoracic and L1 levels as more susceptible to facet violation.…”

“…4,5 Multiple techniques for lumbar supplementation/fixation have been proposed and used and, for reducing the risk of neurovascular injuries and for promoting great stabilization of the construction, pedicle screws have become the preferred method for posterior fixation in lumbar surgeries allowing the stability of the operated level. [6][7][8] Several techniques are proposed for the placement of pedicle screws, including the techniques of Magerl, 9 Roy-Camille et al, 10 and Weinstein et al, 11 among others. 12 In addition, with the popularization of minimally-invasive techniques for spine surgery, the quantity of pedicle screws placement by percutaneous technique is increasing.…”

“…13,14 However, a problem that is often not taken into account in relation to the placement of these screws is the violation of the facet capsule. 6,8,14 Recent studies show rates ranging from 0 to 80% of facet violation of the adjacent level to the more cranial instrumented vertebra, which vary according to the technique used and the surgeon's experience. 15,16 This facet violation of the most instrumented cranial level is one of the factors that is pointed out by studies as a risk factor for the development of disease of the adjacent level, which can lead to degeneration of the adjacent level, and may result in worsening quality of life, and future need for reoperation for the treatment of this level.…”

“… 4 5 Multiple techniques for lumbar supplementation/fixation have been proposed and used and, for reducing the risk of neurovascular injuries and for promoting great stabilization of the construction, pedicle screws have become the preferred method for posterior fixation in lumbar surgeries allowing the stability of the operated level. 6 7 8 …”

“…However, a problem that is often not taken into account in relation to the placement of these screws is the violation of the facet capsule. 6 8 14 Recent studies show rates ranging from 0 to 80% of facet violation of the adjacent level to the more cranial instrumented vertebra, which vary according to the technique used and the surgeon's experience. 15 16 …”