Park Y, Ha JW, Lee YT, et al. Cranial facet joint violations by percutaneously placed pedicle screws adjacent to a minimally invasive lumbar spinal fusion
ABSTRACT Protecting cranial facet joint is a modifiable risk factor that may decrease the incidence of adjacent segment disease after lumbar spinal fusion. Percutaneously instrumented screws may more frequently violate cranial facet joints because of the potential limitation of screw entry site selection. To our knowledge, however, there is no study that has evaluated the cranial facet joint violations adjacent to minimally invasive lumbar fusion related to percutaneously placed pedicle screws.
We investigated the incidence and relating factors of cranial facet joint violations by percutaneous pedicle screws.
A retrospective study of prospectively collecting data.
The sample comprises 184 pedicle screws percutaneously placed at the cranial fusion segments in 92 patients who underwent minimally invasive lumbar spinal fusion.
The facet joint violations adjacent to a cranial fusion segment were examined on the postoperative computed tomography (CT) scans.
Two independent observers retrospectively examined all the postoperative CT images. A facet joint was considered violated if any of the following situations were encountered: pedicle screw clearly within the facet joint; pedicle screw head clearly within the facet joint; and pedicle screw and/or screw head within 1 mm from or abutting the facet joint, without clear joint involvement.
The incidence of the violations was 50% (46/92) of all patients and 31.5% (58/184) of all screws, which were significantly higher than the previously reported rates with the traditional open procedure (50% vs. 23.5% of all patients, p<.001; 31.5% vs. 15.2% of all screws, p<.001). The violations occurred approximately 3.3 times more frequently at the most cranial pedicle screws of L5 pedicle than at the other pedicles (70.8% vs. 42.6%, odds ratio [OR]=3.3, p=.021). Logistic regression analysis revealed a significant trend toward reducing the incidence of the violations as increasing the year of surgery (OR=0.7, p=.008). The incidence showed no significant relationships with patients' age, gender, body mass index, preoperative diagnosis, the number of fused segments, or the side of screw placement.
Our data raise a concern about the higher incidence of cranial facet joint violations by percutaneously placed pedicle screws than that previously reported rates by traditionally instrumented screws. Furthermore, more care should be taken to avoid cranial facet joint violations when the surgeon is a novice to percutaneous pedicle screw placement and/or minimally invasive fusion surgery is considered at the L5-S1 segment.
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ABSTRACT: : Superior-level facet joint violation by pedicle screws may result in increased stress to the level above the instrumentation and may contribute to adjacent segment disease. Previous studies have evaluated facet joint violations in open or percutaneous screw cases, but there are no reports describing a direct institutional comparison. : To compare the incidence of superior-level facet violation for open vs percutaneous pedicle screws and to evaluate patient and surgical factors that affect this outcome. : We reviewed 279 consecutive patients who underwent an index instrumented lumbar fusion from 2007 to 2011 for degenerative spine disease with stenosis with or without spondylolisthesis. We used a computed tomography grading system that represents progressively increasing grades of facet joint violation. Patient and surgical factors were evaluated to determine their impact on facet violation. : Our cohort consisted of 126 open and 153 percutaneous cases. Percutaneous procedures had a higher overall violation grade (P = .02) and a greater incidence of high-grade violations (P = .006) compared with open procedures. Bivariate analysis showed significantly greater violations in percutaneous cases for age < 65 years, obesity, pedicle screws at L4, and 1- and 2-level surgeries. Multivariate analysis showed the percutaneous approach and depth of the spine to be independent risk factors for high-grade violations. : This study demonstrates greater facet violations for percutaneously placed pedicle screws compared with open screws. : ASD, adjacent-segment diseaseBMI, body mass indexCI, confidence intervalOR, odds ratio.Neurosurgery 07/2012; 71(5):962-70. DOI:10.1227/NEU.0b013e31826a88c8 · 3.03 Impact Factor
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ABSTRACT: STUDY DESIGN:: Retrospective study. OBJECTIVES:: To investigate the clinical feasibility and outcomes from direct lateral interbody fusion (DLIF) using autogenous bone grafts and percutaneous posterior instrumentation (PPI) for infectious spondylitis. SUMMARY OF BACKGROUND DATA:: As one of the minimally invasive techniques, PPI has been attempted for various degenerative lumbar spine disorders combined with anterior lumbar interbody fusion or transforaminal lumbar interbody fusion. PPI has been played more roles recently as an internal fixation method for infectious spondylitis. However, the clinical outcomes of DLIF using an autogenous bone graft combined with PPI for infectious spondylitis have been rarely reported. MATERIAL AND METHODS:: Sixteen patients (mean age, 60.3±18.8▒y) who suffereed from pyogenic spondylitis underwent single-stage DLIF using an autogenous iliac bone graft combined with PPI. Clinical and radiological outcomes were evaluated by visual analogue scale (VAS), Oswestry disability index (ODI) and eradication of primary disease. Radiological outcomes were evaluated by changes of affected segmental lordosis and fusion status. RESULTS:: Bony fusion and eradication of primary disease were obtained in all patient except one case during the follow-up (mean, 31.3±13.1▒mo; range 14 - 46▒mo). Preoperative VAS (7±1.2) and ODI (61.3±5.4) scores improved significantly at the last follow-up (VAS, 3.4±1.5; ODI, 32.3±15.4). C-reactive protein normalized at postoperative 20.1±0.7 days (range, 15 - 28▒d). Although height and lordosis in the affected segment were restored by surgery, all patients showed loss of the restored lordosis and height at the final follow-up. Loss of the restored lordosis and height were related to subsidence of the grafted bone. CONCLUSIONS:: Minimally invasive PPI followed by debridement and DLIF was a feasible surgical alternative in our consecutive 16 cases of pyogenic spondylitis. In most cases, the subsidence of anteriorly grafted fusion was inevitable despite successful fusion and eradication of the primary lesion.Journal of spinal disorders & techniques 08/2012; 26(3). DOI:10.1097/BSD.0b013e31826eaf56 · 1.89 Impact Factor
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ABSTRACT: Study Design: Retrospective study comparing cranial facet joint violation rates of open and percutaneous pedicle screws inserted using 3-Dimensional Image-guidance.Objective: To determine the rate of cranial facet joint violation in intraoperative CT image-guided lumbar pedicle screw instrumentation and compare facet joint violation rates between CT image-guided open and percutaneous techniques.Summary of Background Data: Facet joint violation by pedicle screws can potentially result in a higher rate of adjacent segment degeneration. Reported cranial facet joint violation rates ranges from 7% to 100%. Intraoperative image-guidance, which has enhanced pedicle screw placement accuracy, may aid in avoiding impingement of the cranial facet joints.Methods: We reviewed 188 cases of 3-D image-guided lumbar pedicle screw instrumentation from November 2006 to December 2011. The cranial screws of each construct were graded according to the Seo classification (0 = no impingement; 1 = screw head in contact/suspected to be in contact with joint; 2 = screw clearly invaded the joint) on intraoperative axial CT images. Grading was performed by three reviewers. If there was a difference in evaluation, a consensus was reached to arrive at a single grade. Chi-square was used to determine significance between the open and percutaneous group (α = 0.05).Results: A total of 370 screws (245 open, 125 percutaneous) were graded. Overall facet joint violation rate was 18.9% (Grade 1 = 16.2%, Grade 2 = 2.7%). Open technique (Grade 1 = 22.4%, Grade 2 = 4.1%) had a significantly higher violation rate than percutaneous technique (Grade 1 = 4%, Grade 2 = 0%) (p<0.0001). There is a trend of an increasing likelihood of facet joint violation from L1 to L5.Conclusion: The use of intra-operative CT image-guidance in lumbar pedicle screw placement resulted in a facet joint violation rate at the lower end of the reported range in literature. The percutaneous technique has a significantly lower facet violation rate than the open technique.Spine 11/2012; 38(4). DOI:10.1097/BRS.0b013e31827ecbf1 · 2.45 Impact Factor