Charactor of Modality and Resident Level in Pedicle Screw Accuracy and Neurosurgical Education

Objective: Evolving pressure on surgical education necessitates safe and efficient learning of techniques. We evaluated the effect of training year using anatomic, percutaneous fluoroscopy guided and computer navigated techniques on the accuracy of pedicle screw placement to attempt to determine if different modalities may be better suited for different levels of training. Methods: All instrumented thoracic and lumbar cases performed at Detroit Medical Center by the Neurosurgery Service between August 2012 and June 2013 were included.Cases had hardware verified by post-operative CT. Hardware placement was graded according to Mirza SK et al., grade 0 (within pedicle), grade 1 (< 2 mm breach), grade 2 (> 2 mm breach) , and grade 3 (extrapedicular). Pedicle screws were reviewed independently by a resident and attending surgeon. Rates of pedicle breach, EBL, length of case, pedicle size and pedicle starting point were all reviewed. Pedicles were analyzed on PACS system in axial views, using sagittal views to identify the correct level. Results: A total of 306 pedicle screws were evaluated in 36 patients. The overall rate of accurate pedicle screw placement among residents defined as Grade 0 or 1 placement was 86.8%.Fluoroscopically placed screws had significantly less breaches than anatomic screws 11% vs 20% (p = 0.03). Fluoroscopic cases had significantly less medial breeches (20%) than anatomic (50%) (p < 0.05) and computer assisted cases (73%) (p < 0.05). EBL values for fluoroscopic, anatomic and Body Tom cases were 425 cc, 720 cc, and 816 cc respectively. Resident level was found to be inversely proportional to breech rate (R squared 0.45). We did not see any clear difference in breach rate for resident level in different modalities. Conclusion: Supervised neurosurgical residents can place pedicle screws within published rates of acceptable breach. Interestingly our study revealed an inverse relationship between resident experience and pedicle screw accuracy. Fluoroscopic placement of pedicle screws compared to computer assisted and anatomic techniques results in lower medial breach rate and may be better suited for junior level residents.

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Evaluation of C2 pedicle screw placement via the freehand technique by neurosurgical trainees

Journal of Neurosurgery Spine ◽

10.3171/2018.1.spine17875 ◽

2018 ◽

Vol 29 (3) ◽

pp. 235-240 ◽

Cited By ~ 4

Author(s):

Martin H. Pham ◽

Joshua Bakhsheshian ◽

Patrick C. Reid ◽

Ian A. Buchanan ◽

Vance L. Fredrickson ◽

...

Keyword(s):

Pedicle Screw ◽

Medical Center ◽

Pedicle Screws ◽

Screw Placement ◽

Pedicle Screw Placement ◽

C2 Pedicle Screw ◽

Canal Diameter ◽

Screw Length ◽

Freehand Technique ◽

Screw Diameter

OBJECTIVEFreehand placement of C2 instrumentation is technically challenging and has a learning curve due the unique anatomy of the region. This study evaluated the accuracy of C2 pedicle screws placed via the freehand technique by neurosurgical resident trainees.METHODSThe authors retrospectively reviewed all patients treated at the LAC+USC Medical Center undergoing C2 pedicle screw placement in which the freehand technique was used over a 1-year period, from June 2016 to June 2017; all procedures were performed by neurosurgical residents. Measurements of C2 were obtained from preoperative CT scans, and breach rates were determined from coronal reconstructions on postoperative scans. Severity of breaches reflected the percentage of screw diameter beyond the cortical edge (I = < 25%; II = 26%–50%; III = 51%–75%; IV = 76%–100%).RESULTSNeurosurgical residents placed 40 C2 pedicle screws in 24 consecutively treated patients. All screws were placed by or under the guidance of Pham, who is a postgraduate year 7 (PGY-7) neurosurgical resident with attending staff privileges, with a PGY-2 to PGY-4 resident assistant. The authors found an average axial pedicle diameter of 5.8 mm, axial angle of 43.1°, sagittal angle of 23.0°, spinal canal diameter of 25.1 mm, and axial transverse foramen diameter of 5.9 mm. There were 17 screws placed by PGY-2 residents, 7 screws placed by PGY-4 residents, and 16 screws placed by the PGY-7 resident. The average screw length was 26.0 mm, with a screw diameter of 3.5 mm or 4.0 mm. There were 7 total breaches (17.5%), of which 4 were superior (10.0%) and 3 were lateral (7.5%). There were no medial breaches. The breaches were classified as grade I in 3 cases (42.9%), II in 3 cases (42.9%), III in 1 case (14.3%), and IV in no cases. There were 3 breaches that occurred via placement by a PGY-2 resident, 3 breaches by a PGY-4 resident, and 1 breach by the PGY-7 resident. There were no clinical sequelae due to these breaches.CONCLUSIONSFreehand placement of C2 pedicle screws can be done safely by neurosurgical residents in early training. When breaches occurred, they tended to be superior in location and related to screw length choice, and no breaches were found to be clinically significant. Controlled exposure to this unique anatomy is especially pertinent in the era of work-hour restrictions.

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Clinical accuracy of three-dimensional fluoroscopy-based computer-assisted cervical pedicle screw placement: a retrospective comparative study of conventional versus computer-assisted cervical pedicle screw placement

Journal of Neurosurgery Spine ◽

10.3171/2010.5.spine09993 ◽

2010 ◽

Vol 13 (5) ◽

pp. 606-611 ◽

Cited By ~ 75

Author(s):

Yoshimoto Ishikawa ◽

Tokumi Kanemura ◽

Go Yoshida ◽

Zenya Ito ◽

Akio Muramoto ◽

...

Keyword(s):

Pedicle Screw ◽

Three Dimensional ◽

Screw Placement ◽

Computer Assisted ◽

Pedicle Screw Placement ◽

Cervical Pedicle Screw ◽

Retrospective Clinical Study ◽

Significant Difference ◽

Cervical Pedicle ◽

Grade 3

Object The authors performed a retrospective clinical study to evaluate the feasibility and accuracy of cervical pedicle screw (CPS) placement using 3D fluoroscopy-based navigation (3D FN). Methods The study involved 62 consecutive patients undergoing posterior stabilization of the cervical spine between 2003 and 2008. Thirty patients (126 screws) were treated using conventional techniques (CVTs) with a lateral fluoroscopic view, whereas 32 patients (150 screws) were treated using 3D FN. Screw positions were classified into 4 grades based on the pedicle wall perforations observed on postoperative CT. Results The prevalence of perforations in the CVT group was 27% (34 screws): 92 (73.0%), 12 (9.5%), 6 (4.8%), and 16 (12.7%) for Grade 0 (no perforation), Grade 1 (perforation < 1 mm), Grade 2 (perforation ≥ 1 and < 2 mm), and Grade 3 (perforation ≥ 2 mm), respectively. In the 3D FN group, the prevalence of perforations was 18.7% (28 screws): 122 (81.3%), 17 (11.3%), 6 (4%), and 5 (3.3%) for Grades 0, 1, 2, and 3, respectively. Statistical analysis showed no significant difference in the prevalence of Grade 1 or higher perforations between the CVT and 3D FN groups. A higher prevalence of malpositioned CPSs was seen in Grade 2 or higher (17.5% vs 7.3%, p < 0.05) in the 3D FN group and Grade 3 (12.7% vs 7.3%, p < 0.05) perforations in the CVT group. The ORs for CPS malpositioning in the CVT group were 2.72 (95% CI 1.16–6.39) in Grade 2 or higher perforations and 3.89 (95% CI 1.26–12.02) in Grade 3 perforations. Conclusions Three-dimensional fluoroscopy-based navigation can improve the accuracy of CPS insertion; however, severe CPS malpositioning that causes injury to the vertebral artery or neurological complications can occur even with 3D FN. Advanced techniques for the insertion of CPSs and the use of modified insertion devices can reduce the risk of a malpositioned CPS and provide increased safety.

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Določanje velikosti in vstavitvene trajektorije pedikularnih vijakov v računalniškotomografskih (CT) slikah deformacij prsne hrbtenice: primerjava ročnega in računalniško podprtega predoperacijskega načrtovanja

Slovenian Medical Journal ◽

10.6016/zdravvestn.1747 ◽

2017 ◽

Vol 85 (11-12) ◽

Author(s):

Dejan Knez ◽

Janez Mohar ◽

Robert Janez Cirman ◽

Boštjan Likar ◽

Franjo Pernuš ◽

...

Keyword(s):

Pedicle Screw ◽

Preoperative Planning ◽

Sagittal Plane ◽

Pedicle Screws ◽

Ct Images ◽

Screw Placement ◽

Computer Assisted ◽

Pedicle Screw Placement ◽

Pull Out ◽

Significant Difference

Background: Vertebral fixation by pedicle screw placement is the most frequently applied fixation technique in spinal surgery. In this retrospective study we present a comparison of manual and computer-assisted preoperative planning of pedicle screw placement in three-dimensional (3D) computed tomography (CT) images of deformities in the thoracic spine.Methods: Manual planning of the pedicle screw size and trajectory was performed by two orthopedic surgeons using a dedicated software for preoperative planning of surgical procedures, while computer-assisted planning was performed by automated image processing and analysis techniques through the optimization of screw fastening strength. The size (diameter and length) and trajectory (pedicle crossing point, inclination in the sagittal plane, inclination in the axial plane) were obtained for 316 pedicle screws from 3D CT images of 17 patients with thoracic spinal deformities.Results: the analysis of pedicle screw parameters, obtained by two manual and one computer-assisted planning, indicated a statistically significant diﬀerence in the screw size (p < 0.05) and trajectory (p < 0.001). Computer-assisted planning proposed wider (p < 0.05) and longer (p < 0.001) screws with a higher (p < 0.001) normalized fastening strength.Conclusions: The comparison revealed consistency between manual and computer-assisted planning of the pedicle screw size and trajectory, except for the screw inclination in the sagittal plane, as manual planning followed more the straight-forward while computer-assisted planning followed more the anatomical insertion technique. While being faster, more repeatable and more reliable than manual planning, computer-assisted planning was also linked with a higher screw fastening strength and consequently a higher screw pull-out strength.

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Functional outcome of computer-assisted spinal pedicle screw placement: a systematic review and meta-analysis of 23 studies including 5,992 pedicle screws

European Spine Journal ◽

10.1007/s00586-009-1258-4 ◽

2010 ◽

Vol 19 (3) ◽

pp. 370-375 ◽

Cited By ~ 102

Author(s):

Rajeev Verma ◽

Sonal Krishan ◽

Kurt Haendlmayer ◽

A. Mohsen

Keyword(s):

Systematic Review ◽

Functional Outcome ◽

Pedicle Screw ◽

Meta Analysis ◽

Pedicle Screws ◽

Screw Placement ◽

Computer Assisted ◽

Pedicle Screw Placement

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Techniques and Tips for Freehand Placement of C7 Pedicle Screws With Respect to Cervicothoracic Constructs: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opz235 ◽

2019 ◽

Vol 18 (6) ◽

pp. E234-E234 ◽

Cited By ~ 1

Author(s):

William Clifton ◽

Steve Edwards ◽

Christopher Louie ◽

Conrad Dove ◽

Aaron Damon ◽

...

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Screw Placement ◽

Lateral Mass ◽

Pedicle Screw Placement ◽

Medial Border ◽

Surgical Video ◽

Starting Point ◽

Patient Consent ◽

Slight Displacement

Abstract We present a surgical video highlighting the technical pearls for C7 pedicle screw placement with respect to cervicothoracic constructs. Pedicle screw placement into C7 has been shown to enhance the biomechanical stability of both cervical and cervicothoracic constructs and is safe for patient related outcomes.1,2 Rod placement across the cervicothoracic junction is known to be difficult because of the variable starting point of the C7 pedicle screw, which may cause misalignment of the polyaxial heads with respect to the C7 and C6 screw heads. Using our step-wise method of anatomic screw placement, this potential pitfall is minimized. The T1 pedicle screw is placed first. The C6 lateral mass screw starting point is displaced slightly superiorly from the midpoint of the lateral mass in order to make room for the polyaxial head of the C7 pedicle screw. A small laminotomy is performed in order to find the medial border of the C7 pedicle. Palpation of the medial border allows for an approximation of the pedicle limits. The cranial-caudal angle of drilling is perpendicular to the C7 superior facet, and the medial-lateral trajectory typically falls between 15 and 20 degrees medial. Once the pedicle is cannulated, a ball-tipped probe is used to confirm intraosseous position. A rod is cut and contoured to the appropriate length of the construct. The C7 pedicle screw should capture the rod easily with slight displacement of the polyaxial head. Postinstrumentation anteroposterior and lateral fluoroscopy are performed to confirm good position of the lateral mass and pedicle screws. Patient consent was not required for this cadaveric surgical video.

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Thoracic, Lumbar, and Sacral Pedicle Screw Placement Using Stryker-Ziehm Virtual Screw Technology and Navigated Stryker Cordless Driver 3: Technical Note

10.20944/preprints201804.0064.v1 ◽

2018 ◽

Author(s):

Praveen Satarasinghe ◽

D. Kojo Hamilton ◽

Michael Jace Tarver ◽

Robert J. Buchanan ◽

Michael T. Koltz

Keyword(s):

Pedicle Screw ◽

Three Dimensional ◽

Pedicle Screws ◽

Technical Note ◽

Screw Placement ◽

Computer Assisted ◽

Anatomical Landmarks ◽

Pedicle Screw Placement ◽

Intraoperative Ct ◽

Spine Stabilization

Object. Utilization of pedicle screws (PS) for spine stabilization is common in spinal surgery. With reliance on visual inspection of anatomical landmarks prior to screw placement, the free-hand technique requires a high level of surgeon skill and precision. Three-dimensional (3D) computer-assisted virtual neuronavigation improves the precision of PS placement and minimize steps. Methods. Twenty-three patients with degenerative, traumatic, or neoplastic pathologies received treatment via a novel three-step PS technique that utilizes a navigated power driver in combination with virtual screw technology. 1) Following visualization of neuroanatomy using intraoperative CT, a navigated 3-mm match stick drill bit was inserted at anatomical entry point with screen projection showing virtual screw. 2) Navigated Stryker Cordless Driver with appropriate tap was used to access vertebral body through pedicle with screen projection again showing virtual screw. 3) Navigated Stryker Cordless Driver with actual screw was used with screen projection showing the same virtual screw. One hundred and forty-four consecutive screws were inserted using this three-step, navigated driver, virtual screw technique. Results. Only 1 screw needed intraoperative revision after insertion using the three-step, navigated driver, virtual PS technique. This amounts to a 0.69% revision rate. One hundred percent of patients had intraoperative CT reconstructed images to confirm hardware placement. Conclusions. Pedicle screw placement utilizing the Stryker-Ziehm neuronavigation virtual screw technology with a three step, navigated power drill technique is safe and effective.

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Percutaneous pedicle screw placement with computer-navigated mapping in place of Kirschner wires

Journal of Neurosurgery Spine ◽

10.3171/2013.7.spine121157 ◽

2013 ◽

Vol 19 (5) ◽

pp. 608-613 ◽

Cited By ~ 9

Author(s):

Thomas J. Gianaris ◽

Gregory M. Helbig ◽

Eric M. Horn

Keyword(s):

Pedicle Screw ◽

Navigation System ◽

Pedicle Screws ◽

Screw Placement ◽

Computer Assisted ◽

Anatomical Landmarks ◽

Pedicle Screw Placement ◽

Assisted Navigation ◽

Percutaneous Pedicle Screw ◽

K Wires

Object Percutaneous pedicle screw insertion techniques are commonly used to treat a variety of spinal disorders. Typically, Kirschner (K)-wires are used to guide the insertion of taps and screws during placement since the normal anatomical landmarks are not visualized. The use of K-wires adds risks, such as vascular and nerve injuries as well as increased radiation exposure given the use of fluoroscopy. The authors describe a series of patients who had percutaneous pedicle screws placed using a new computer-assisted navigation technique without the need for K-wires. Methods Minimally invasive percutaneous pedicle screw placement in the thoracic and lumbar spine was performed in a consecutive series of 15 patients for a variety of spinal pathologies. Intraoperative 3D CT images were obtained and used with a computer-assisted navigation system to insert an awl-tap into each pedicle. The tap location in the pedicle was marked with the navigation software, and the awl-tap was then removed. The navigation system was used to identify each landmark to insert the pedicle screw. Connecting rods were then inserted percutaneously under fluoroscopic guidance. Postoperative CT scans were obtained in each patient to evaluate screw placement. Results On postprocedure scanning, only 1 screw had a minor lateral and superior breach that was asymptomatic. To date, there have been no hardware failures. Conclusions Percutaneous pedicle screws can be placed effectively and safely without the use of K-wires.

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Stereotactic Navigation for Placement of Pedicle Screws in the Thoracic Spine

Neurosurgery ◽

10.1097/00006123-200104000-00015 ◽

2001 ◽

Vol 48 (4) ◽

pp. 771-779 ◽

Cited By ~ 33

Author(s):

Andrew S. Youkilis ◽

Douglas J. Quint ◽

John E. McGillicuddy ◽

Stephen M. Papadopoulos

Keyword(s):

Pedicle Screw ◽

Thoracic Spine ◽

Medical Center ◽

Pedicle Screws ◽

Screw Placement ◽

Spinal Instability ◽

Pedicle Screw Placement ◽

Image Guided ◽

Thoracic Pedicle Screw ◽

Thoracic Pedicle Screws

Abstract OBJECTIVE Pedicle screw fixation in the lumbar spine has become the standard of care for various causes of spinal instability. However, because of the smaller size and more complex morphology of the thoracic pedicle, screw placement in the thoracic spine can be extremely challenging. In several published series, cortical violations have been reported in up to 50% of screws placed with standard fluoroscopic techniques. The goal of this study is to evaluate the accuracy of thoracic pedicle screw placement by use of image-guided techniques. METHODS During the past 4 years, 266 image-guided thoracic pedicle screws were placed in 65 patients at the University of Michigan Medical Center. Postoperative thin-cut computed tomographic scans were obtained in 52 of these patients who were available to enroll in the study. An impartial neuroradiologist evaluated 224 screws by use of a standardized grading scheme. All levels of the thoracic spine were included in the study. RESULTS Chart review revealed no incidence of neurological, cardiovascular, or pulmonary injury. Of the 224 screws reviewed, there were 19 cortical violations (8.5%). Eleven (4.9%) were Grade II (≤2 mm), and eight (3.6%) were Grade III (>2 mm) violations. Only five screws (2.2%), however, were thought to exhibit unintentional, structurally significant violations. Statistical analysis revealed a significantly higher rate of cortical perforation in the midthoracic spine (T4–T8, 16.7%; T1–T4, 8.8%; and T9–T12, 5.6%). CONCLUSION The low rate of cortical perforations (8.5%) and structurally significant violations (2.2%) in this retrospective series compares favorably with previously published results that used anatomic landmarks and intraoperative fluoroscopy. This study provides further evidence that stereotactic placement of pedicle screws can be performed safely and effectively at all levels of the thoracic spine.

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