scholarly journals Increased Axial Facet Angle Correlates With Poor Percutaneous Pedicle Screw Placement

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Guang-Ting Cong ◽  
James Dowdell ◽  
Avani Vaishnav ◽  
Steven Mcanany ◽  
Sravisht Iyer ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Preoperative Planning ◽  
Safe Zone ◽  
Screw Placement ◽  
Lumbosacral Spine ◽  
Pedicle Screw Placement ◽  
Instrumented Fusion ◽  
Percutaneous Pedicle Screw ◽  
The Mean ◽  
Global Mean

Abstract INTRODUCTION To test the hypothesis that axial facet angle correlates with poor pedicle screw placement (and especially facet violation) in percutaneous fluoroscopy-guided pedicle screw placement. METHODS A total of 95 consecutive patients who underwent minimally invasive fluoroscopic instrumented fusion of the lumbar or lumbosacral spine were included. Postoperative computed tomography (CT) was used to categorize pedicle screw placement as follows: good (no breach), acceptable (breach within safe zone and/or any amount of tip breach), poor (outside safe zone, and/or violation of unfused facet, and/or unfused endplate violation). Safe zone was defined as 4 mm lateral or 2 mm inferomedial breach of pedicle cortex. Axial facet angle was measured against a midsagittal line. Global mean axial facet angles at L4, L5, and S1 were calculated. RESULTS Of the total 349 screws, 38 (10.7%) were categorized as poor placement, and of these 31 (82%) were due to unfused facet violation. Global axial facet angle means were 36.8 degrees for L4, 45.8 for L5, and 50.5 for S1. Mean axial facet angles associated with poorly placed screws were 42.7 degrees for L4 and 51.4 degrees for L5 these angles are higher than the global means at L4 (P = .063) and L5 (P = .028). Subgroup analysis demonstrated that the mean axial facet angles associated with unfused facet violation was 44.0 degrees for L4 and 53.2 degrees for L5. These means were significantly higher than the global means at L4 (P = .027) and L5 (P = .009). No poor screw placement was found at the S1 level. CONCLUSION Increased axial facet angle significantly correlates with poor screw placement and especially with facet violation in percutaneous fluoroscopy-guided pedicle screw placement at L4 and L5. Care should be taken to evaluate for high axial facet angles in preoperative planning.

scholarly journals Anatomic considerations for C2 pedicle screw placement: the use of computerized tomography measurements

2009 ◽  
Vol 8 (1) ◽  
pp. 80-83
Author(s):  
Adebukoa Onibokun ◽  
Simona Bistazzoni ◽  
Marco Sassi ◽  
Larry T. Khoo
Keyword(s):  
Pedicle Screw ◽  
Computerized Tomography ◽  
Preoperative Planning ◽  
Screw Placement ◽  
Pedicle Screw Placement ◽  
C2 Pedicle Screw ◽  
Anatomical Knowledge ◽  
Axial Ct ◽  
The Mean ◽  
Pedicle Width

OBJECTIVE: more detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial CT. METHODS: ninety three patients (47 males, 46 females mean age 48 years) who had cervical spinal CT imaging performed were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (PW, the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, that is, the angle between the pedicle axis and the midline of the vertebral body). RESULTS: the overall mean pedicle width was 5.8 1.2mm. The mean pedicle width in males (6.01.3mm) was greater than that in the female subjects (5.6 1.1mm). This difference was not found to be statistically significant (p=.6790). The overall mean pedicle transverse angle was 43.93.9 degrees. The mean PTA in males was 43.23.8 degrees, while that in females was 44.73.7 degrees. CONCLUSION: preoperative planning is absolutely mandatory, particularly in determining not only screw trajectory, but in analyzing individual patient anatomy and reception to a C2 pedicle screw.

scholarly journals First in-human report of the clinical accuracy of thoracolumbar percutaneous pedicle screw placement using augmented reality guidance

2021 ◽  
Vol 51 (2) ◽  
pp. E10
Author(s):  
Alexander T. Yahanda ◽  
Emelia Moore ◽  
Wilson Z. Ray ◽  
Brenton Pennicooke ◽  
Jack W. Jennings ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Lower Extremity ◽  
Pedicle Screw ◽  
Pedicle Screws ◽  
Screw Placement ◽  
Spinal Tumors ◽  
Pedicle Screw Placement ◽  
Percutaneous Pedicle Screw ◽  
Clinical Accuracy ◽  
The Mean

OBJECTIVE Augmented reality (AR) is an emerging technology that has great potential for guiding the safe and accurate placement of spinal hardware, including percutaneous pedicle screws. The goal of this study was to assess the accuracy of 63 percutaneous pedicle screws placed at a single institution using an AR head-mounted display (ARHMD) system. METHODS Retrospective analyses were performed for 9 patients who underwent thoracic and/or lumbar percutaneous pedicle screw placement guided by ARHMD technology. Clinical accuracy was assessed via the Gertzbein-Robbins scale by the authors and by an independent musculoskeletal radiologist. Thoracic pedicle subanalysis was also performed to assess screw accuracy based on pedicle morphology. RESULTS Nine patients received thoracic or lumbar AR-guided percutaneous pedicle screws. The mean age at the time of surgery was 71.9 ± 11.5 years and the mean number of screws per patient was 7. Indications for surgery were spinal tumors (n = 4, 44.4%), degenerative disease (n = 3, 33.3%), spinal deformity (n = 1, 11.1%), and a combination of deformity and infection (n = 1, 11.1%). Presenting symptoms were most commonly low-back pain (n = 7, 77.8%) and lower-extremity weakness (n = 5, 55.6%), followed by radicular lower-extremity pain, loss of lower-extremity sensation, or incontinence/urinary retention (n = 3 each, 33.3%). In all, 63 screws were placed (32 thoracic, 31 lumbar). The accuracy for these screws was 100% overall; all screws were Gertzbein-Robbins grade A or B (96.8% grade A, 3.2% grade B). This accuracy was achieved in the thoracic spine regardless of pedicle cancellous bone morphology. CONCLUSIONS AR-guided surgery demonstrated a 100% accuracy rate for the insertion of 63 percutaneous pedicle screws in 9 patients (100% rate of Gertzbein-Robbins grade A or B screw placement). Using an ARHMS system for the placement of percutaneous pedicle screws showed promise, but further validation using a larger cohort of patients across multiple surgeons and institutions will help to determine the true accuracy enabled by this technology.

Threshold-based Monitoring of Compound Muscle Action Potentials for Percutaneous Pedicle Screw Placement in the Lumbosacral Spine

Spine ◽  
2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Yoichi Tani ◽  
Takanori Saito ◽  
Shinichiro Taniguchi ◽  
Masayuki Ishihara ◽  
Masaaki Paku ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Action Potentials ◽  
Screw Placement ◽  
Lumbosacral Spine ◽  
Muscle Action ◽  
Pedicle Screw Placement ◽  
Percutaneous Pedicle Screw ◽  
Compound Muscle Action Potentials

scholarly journals Three-dimensional assessment of robot-assisted pedicle screw placement accuracy and instrumentation reliability based on a preplanned trajectory

2020 ◽  
Vol 33 (4) ◽  
pp. 519-528
Author(s):  
Bowen Jiang ◽  
Zach Pennington ◽  
Alex Zhu ◽  
Stavros Matsoukas ◽  
A. Karim Ahmed ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Tertiary Care ◽  
Pedicle Screws ◽  
Screw Placement ◽  
Lumbosacral Spine ◽  
Grading System ◽  
Angular Deviation ◽  
Pedicle Screw Placement ◽  
Placement Accuracy ◽  
The Mean

OBJECTIVERobotic spine surgery systems are increasingly used in the US market. As this technology gains traction, however, it is necessary to identify mechanisms that assess its effectiveness and allow for its continued improvement. One such mechanism is the development of a new 3D grading system that can serve as the foundation for error-based learning in robot systems. Herein the authors attempted 1) to define a system of providing accuracy data along all three pedicle screw placement axes, that is, cephalocaudal, mediolateral, and screw long axes; and 2) to use the grading system to evaluate the mean accuracy of thoracolumbar pedicle screws placed using a single commercially available robotic system.METHODSThe authors retrospectively reviewed a prospectively maintained, IRB-approved database of patients at a single tertiary care center who had undergone instrumented fusion of the thoracic or lumbosacral spine using robotic assistance. Patients with preoperatively planned screw trajectories and postoperative CT studies were included in the final analysis. Screw accuracy was measured as the net deviation of the planned trajectory from the actual screw trajectory in the mediolateral, cephalocaudal, and screw long axes.RESULTSThe authors identified 47 patients, 51% male, whose pedicles had been instrumented with a total of 254 screws (63 thoracic, 191 lumbosacral). The patients had a mean age of 61.1 years and a mean BMI of 30.0 kg/m2. The mean screw tip accuracies were 1.3 ± 1.3 mm, 1.2 ± 1.1 mm, and 2.6 ± 2.2 mm in the mediolateral, cephalocaudal, and screw long axes, respectively, for a net linear deviation of 3.6 ± 2.3 mm and net angular deviation of 3.6° ± 2.8°. According to the Gertzbein-Robbins grading system, 184 screws (72%) were classified as grade A and 70 screws (28%) as grade B. Placement of 100% of the screws was clinically acceptable.CONCLUSIONSThe accuracy of the discussed robotic spine system is similar to that described for other surgical systems. Additionally, the authors outline a new method of grading screw placement accuracy that measures deviation in all three relevant axes. This grading system could provide the error signal necessary for unsupervised machine learning by robotic systems, which would in turn support continued improvement in instrumentation placement accuracy.

Accuracy and technical limits of percutaneous pedicle screw placement in the thoracolumbar spine

2021 ◽  
Author(s):  
Yann Philippe Charles ◽  
Yves Ntilikina ◽  
Arnaud Collinet ◽  
Sébastien Schuller ◽  
Julien Garnon ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Thoracolumbar Spine ◽  
Screw Placement ◽  
Pedicle Screw Placement ◽  
Percutaneous Pedicle Screw

scholarly journals Radiographic Accuracy of Percutaneous Pedicle Screw Placement in Fluoroscopic- Versus CT Navigation-Guided Lumbar Spine Instrumentation

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Guang-Ting Cong ◽  
Avani Vaishnav ◽  
Joseph Barbera ◽  
Hiroshi Kumagai ◽  
James Dowdell ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Minimally Invasive ◽  
Pedicle Screw ◽  
Spinal Instrumentation ◽  
Screw Placement ◽  
Pedicle Screw Placement ◽  
Intraoperative Computed Tomography ◽  
Percutaneous Pedicle Screw ◽  
Spine Instrumentation ◽  
Surgical Methods

Abstract INTRODUCTION Posterior spinal instrumentation for fusion using intraoperative computed tomography (CT) navigation is gaining traction as an alternative to the conventional two-dimensional fluoroscopic-guided approach to percutaneous pedicle screw placement. However, few studies to date have directly compared outcomes of these 2 minimally invasive instrumentation methods. METHODS A consecutive cohort of patients undergoing primary percutaneous posterior lumbar spine instrumentation for spine fusion was retrospectively reviewed. Revision surgeries or cases converted to open were excluded. Accuracy of screw placement was assessed using a postoperative CT scan with blinding to the surgical methods used. The Gertzbein-Robbins classification was used to grade cortical breach: Grade 0 (<0 mm cortical breach), Grade I (<2 mm), Grade II (2-4 mm), Grade III (4-6 mm), and Grade IV (>6 mm). RESULTS CT navigation was found to significantly improve accuracy of screw placement (P < .022). There was significantly more facet violation of the unfused level in the fluoroscopy group vs the CT group (9% vs 0.5%; P < .0001). There was also a higher proportion of poor screw placement in the fluoroscopy group (10.1% vs 3.6%). No statistical difference was found in the rate of tip breach, inferomedial breach, or lateral breach. Regression analysis showed that fluoroscopy had twice the odds of incurring poor screw placement as compared to CT navigation. CONCLUSION This radiographic study comparing screw placement in minimally invasive fluoroscopy- vs CT navigation-guided lumbar spine instrumentation provides evidence that CT navigation significantly improves accuracy of screw placement, especially in optimizing the screw trajectory so as to avoid facet violation. Long-term follow-up studies should be performed to ascertain whether this difference can contribute to an improvement in clinical outcomes.

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