Accuracy of percutaneous pedicle screw insertion in spinal fixation of traumatic thoracic and lumbar spine fractures
- Department of Neurosurgery, Sheikh Khalifa Specialty Hospital, Ras Al-Khaimah, United Arab Emirates
- Department of Spine Surgery, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
Department of Spine Surgery, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
DOI:10.4103/sni.sni_5_18Copyright: © 2018 Surgical Neurology International This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.
How to cite this article: Tamer Orief, Mohammad Alfawareh, Mohammad Halawani, Walid Attia, Khaled Almusrea. Accuracy of percutaneous pedicle screw insertion in spinal fixation of traumatic thoracic and lumbar spine fractures. 10-Apr-2018;9:78
How to cite this URL: Tamer Orief, Mohammad Alfawareh, Mohammad Halawani, Walid Attia, Khaled Almusrea. Accuracy of percutaneous pedicle screw insertion in spinal fixation of traumatic thoracic and lumbar spine fractures. 10-Apr-2018;9:78. Available from: http://surgicalneurologyint.com/?post_type=surgicalint_articles&p=8831
Background:Percutaneous insertion of pedicle screws was developed as a minimally invasive alternative to the different open spinal procedures. Here, we determined the accuracy of percutaneous pedicle screw insertion.
Methods:For 60 consecutive patients with thoracic/lumbar spine fractures, computed tomography (CT) studies were utilized to assess the accuracy of percutaneous pedicle screw positioning. A screw was identified as cortical encroachment if the pedicle cortex could not be visualized, while Frank penetration was defined if screw trajectory being located obviously outside the pedicle boundaries [e.g., subdivided as minor (6 mm)].
Results:Sixty patients received 410 pedicle screws placed percutaneously. Of these, 294 screws (71.7%) were ideally placed inside the pedicle. Alternatively, 56 screws (13.6%: 18 cases) showed pedicle encroachment and 60 screws (14.6%: 23 cases) showed pedicle penetration, e.g., 38 (9.2%) minor penetration and 22 (5.3%) were malpositioned (4.8% moderate and 0.5% severe). New postoperative neurological symptoms were identified in two cases (3.3%), where severe screw penetration was identified.
Conclusion:Percutaneous pedicle screw insertion in 60 patients receiving 410 percutaneously placed pedicle screws yielded 294 ideally placed, 56 showing pedicle encroachment, 60 (14.3%, 23 cases) exhibiting varying degrees of pedicle penetration, with 2 showing new postoperative neurological deficits (severe screw misplacement). Of interest, this technique proved to be more challenging in the thoracic spine. Larger series are needed to better establish the average rate of neurological injuries associated with percutaneous thoracic/lumbar screw misplacement.
Keywords: Fixation, fractures, percutaneous, screw
The percutaneous insertion of pedicle screws into the thoracic and/or lumbar spine (T/L) is a minimally invasive alternative to open surgical techniques. However, it is important to analyze the accuracy, safety, and reliability of the percutaneous T/L screw insertion as screw misplacement may contribute to neurological deficits and instability of the construct (e.g., resulting in screw loosening).
Here, we utilized computed tomography (CT) to document postoperative screw positioning in 60 consecutive patients with traumatic thoracic and lumbar spine fractures (e.g., axial assessment of medial and lateral pedicle penetration/breaches).
Within the first week following traumatic spinal injuries, 60 consecutive patients underwent the percutaneous placement of 410 transpedicular screws to address thoracic and/or lumbar (T/L) spine fractures addressing
Preoperative CT scans were utilized to plan the appropriate screw diameter and length to be utilized intraoperatively. A classical percutaneous technique was utilized to insert 4.5 and 6.5 mm pedicle screws (e.g., depending on the pedicle diameter in the preoperative CT scans).
Within the first postoperative week, screw locations were evaluated on thin-slice CT scans by three independent observers (an experienced spinal surgeon and two senior radiologists). On CT, the cortical walls of the pedicles were examined for bone defects, while the most superior and inferior slices of each pedicle were assessed to detect caudal/cranial screw penetration. Frank screw malpositioning, as defined by Learch and Wiesner, and new postoperative neurological symptoms deficits were assessed for all patients[
The highest level of percutaneous instrumentation of this series was T7, and the lowest was L5. Of 410 screws, 175 (42.6%) were placed at the thoraco-lumbar junction (T11–L2) [
Only 2 patients (3.33%) exhibited new postoperative neurological deficits. In the first patient, the right L4 root injury was attributed to severe medial screw penetration of the right L4 pedicle: this deficit partially resolved after screw adjustment (motor fully resolved/residual sensory deficit) [
Four patients had pin tract superficial infection not related to the position of the screws; all were treated with antibiotics, and none of required revision surgery.
The reported misplacement rates for thoracic and lumbar percutaneously placed pedicle screws ranges from 8 to 40%.[
Heintel et al. evaluated 111 patients who underwent 502 percutaneous screw placement; 98% of screws were ideally placed in the pedicle according to their postoperative CT evaluations.[
Schizas et al. reported a 23% incidence of screw penetration (15 patients, 60 percutaneous screws); severe pedicle penetration of 3.3% with an overall screw penetration rate of 30% on sagittal images.[
In the present study, the authors utilized CT to postoperatively analyze the placement of 410 screws in 60 patients; 294 screws (71.7%) were ideally placed, 13.6% showed encroachment. Another 14.6% demonstrated screw penetration; mild (9.2%), moderate (4.8%), and severe (0.5%) [
Previously, different studies documented varying criteria for screw misplacement. Heintel et al. evaluated 111 patients who underwent 502 percutaneous screw placements; 98% of screws were ideally placed in the pedicle according to the postoperative CT evaluation.[
Here the question is on the accuracy of CT analysis, given the nearly perfect incidence of screw placement. Schizas et al. reported a 23% incidence of screw penetration (15 patients, 60 percutaneous screws): severe pedicle penetration of 3.3% with an overall screw penetration rate of 30% was demonstrated on sagittal images.[
Percutaneous thoracic/lumbar pedicle screw insertion is demanding and should only be performed by experienced spine surgeons familiar with the technique of pedicle screw placement. Notably, it is even more challenging in the thoracic spine. Although the risk of screw misplacement of 5.3% is low, larger series are needed to better establish the average rate of neurological injuries associated with screw misplacement.
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Conflicts of interest
There are no conflicts of interest.
1. Farber GL, Place HM, Mazur RA, Jones DE, Damiano TR. Accuracy of pedicle screw placement in lumbar fusions by plain radiographs and computed tomography. Spine. 1995. 20: 1494-9
2. Heintel TM, Berglehner A, Meffert R. Accuracy of percutaneous pedicle screws for thoracic and lumbar spine fractures: A prospective trial. Eur Spine J. 2013. 22: 495-502
3. Learch TJ, Massie JB, Pathria MN, Ahlgren BA, Garfin SR. Assessment of pedicle screw placement utilizing conventional radiography and computed tomography: A proposed systematic approach to improve accuracy of interpretation. Spine (1976). 2004. 29: 767-73
4. Schizas C, Michel J, Kosmopoulos V. Computed tomography assessment of pedicle screw insertion in percutaneous posterior transpedicular stabilization. Eur Spine J. 2007. 16: 613-7
5. Schulze CJ, Munzinger E, Weber U. Clinical relevance of accuracy of pedicle screw placement. A computed tomographic-supported analysis. Spine. 1998. 23: 2215-20
6. Weinstein JN, Spratt KF, Spenegler D, Brick C, Reid S. Spinal pedicle fixation: reliability and validity of roentgenogram-based assessment and surgical factors on successful screw placement. Spine. 1988. 13: 1012-8