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

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

Psychology and Mental Health Care ◽

10.31579/2637-8892/021 ◽

2018 ◽

Vol 2 (1) ◽

pp. 01-04

Author(s):

Anbis El Hakim

Keyword(s):

Pedicle Screw ◽

Medical Center ◽

Pedicle Screws ◽

Screw Placement ◽

Computer Assisted ◽

Training Methods ◽

Pedicle Screw Placement ◽

Starting Point ◽

Grade 3 ◽

Efficient Learning

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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The "slide technique" - a novel free-hand method of subaxial cervical pedicle screw placement

10.21203/rs.2.16510/v1 ◽

2019 ◽

Author(s):

Bin Liu ◽

Xiangyang Liu ◽

Xiongjie Shen ◽

Guoping Wang ◽

Yixin Chen

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Screw Placement ◽

Target Area ◽

Lateral Mass ◽

Pedicle Screw Placement ◽

Cervical Pedicle Screw ◽

Screw Insertion ◽

Cervical Pedicle ◽

Slide Technique

Abstract Background : Cervical Pedicle Screw(CPS) placement is a challenging work due to high risk of neurovascular complications. Although there have been a number of different free-hand or navigation assisted techniques for CPS placement, perforations always occur during screw insertion, especially lateral perforation. The objective of this research is to describe a novel free-hand technique for subaxial CPS placement (C3–C7) for improving security and decreasing the chances of perforation. Methods : Thirty-two patients undergoing surgery with CPS instrumentation (C3–C7) at our institute between June 2017 and December 2018 were included in the study. All the patients had cervical trauma, and pedicle screw insertion was made according to the free-hand “slide technique”. Lamina, lateral mass and facet joint of the target area were clearly exposed and the optimal entry point was found on the lateral mass posterior surface. A pedicular probe was then inserted and gently advanced. During the pedicle probe insertion, the cortex of the medial margin of the pedicle acted as a “slide” to permit safe insertion of the screw. If the pedicle screw pathway was intact, screw of appropriate size was carefully placed. Three-dimensional (3D) CT imaging reconstruction was performed in all the patients after surgery, and screw perforations were graded with the Gertzbein-Robbins classification. Results : A total of 257 CPSs (C3-7) were inserted, of which 41 CPSs in C3, 61 CPSs in C4, 55 CPSs in C5, 53 CPSs in C6, and 47 CPSs in C7. The diameter and length of CPSs were 3.5 mm and 22-26 mm respectively. According to the Gertzbein-Robbins classification, grade 0, 231 screws; grade 1, 19 screws; and grade 2, 7 screws. No neurovascular complications occurred stemming from malpositioning of pedicle screws. In perforated screws (26 screws), lateral perforations were 16, medical perforations were 5, and inferior perforations were 4. Conclusions : The initial usage result show the “slide technique” is a safe, effective and cost-effective technique for pedicle screw placement in the cervical spine. This is the first report of such technique, we recommend it to wide practical application though further studies are needed.

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The"slide technique"-a novel free-hand method of subaxial cervical pedicle screw placement

10.21203/rs.2.16510/v2 ◽

2020 ◽

Author(s):

Bin Liu ◽

Xiangyang Liu ◽

Xiongjie Shen ◽

Guoping Wang ◽

Yixin Chen

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Screw Placement ◽

Target Area ◽

Lateral Mass ◽

Pedicle Screw Placement ◽

Cervical Pedicle Screw ◽

Screw Insertion ◽

Cervical Pedicle ◽

Slide Technique

Abstract Background: Cervical Pedicle Screw(CPS) placement is a challenging work due to the high risk of neurovascular complications. Although there have been several different free-hand or navigation assisted techniques for CPS placement, perforations may occur during screw insertion, especially lateral perforation. The objective of this manuscript is to describe a novel free-hand technique for subaxial CPS placement (C3–C7) and to evaluate if it decreases the chances of perforation.Methods: Thirty-two patients undergoing surgery with CPS instrumentation (C3–C7) at our institute between June 2017 and December 2018 were included in this study. All the patients had cervical trauma, and pedicle screw insertion was performed according to the free-hand “slide technique”. The lamina, lateral mass and facet joint of the target area were exposed and the optimal entry point was found on the lateral mass posterior surface. A pedicular probe was then inserted and gently advanced. During the pedicle probe insertion, the cortex of the medial margin of the pedicle acted as a slide to permit the safe insertion of the screw. If the pedicle screw pathway was intact, the screw of the appropriate size was carefully placed. Three-dimensional (3D) CT imaging reconstruction was performed in all the patients after surgery, and screw perforations were graded with the Gertzbein-Robbins classification.Results: A total of 257 CPSs (C3-7) were inserted, of which 41 CPSs were in C3, 61 CPSs were in C4, 55 CPSs were in C5, 53 CPSs were in C6, and 47 CPSs were in C7. The diameter and length of CPSs were 3.5 mm and 22-26 mm respectively. According to the Gertzbein-Robbins classification, grade 0, 231 screws; grade 1, 19 screws; and grade 2, 7 screws. No neurovascular complications occurred stemming from malpositioning of pedicle screws. Among perforated screws (26 screws), there were 16 lateral perforations, 5 medical perforations, and 4 inferior perforations.Conclusions: The initial usage result shows the “slide technique” is a safe, effective and cost-effective technique for pedicle screw placement in the cervical spine. This is the first report of such a technique. We recommend its use though further studies are needed.

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The accuracy of pedicle screw placement using intraoperative image guidance systems

Journal of Neurosurgery Spine ◽

10.3171/2013.11.spine13413 ◽

2014 ◽

Vol 20 (2) ◽

pp. 196-203 ◽

Cited By ~ 155

Author(s):

Alexander Mason ◽

Renee Paulsen ◽

Jason M. Babuska ◽

Sharad Rajpal ◽

Sigita Burneikiene ◽

...

Keyword(s):

Pedicle Screw ◽

Image Guidance ◽

Pedicle Screws ◽

Screw Placement ◽

Data Sets ◽

Pedicle Screw Placement ◽

Fluoroscopic Image ◽

Fluoroscopic Navigation ◽

Guidance Systems ◽

Accuracy Rates

Object Several retrospective studies have demonstrated higher accuracy rates and increased safety for navigated pedicle screw placement than for free-hand techniques; however, the accuracy differences between navigation systems has not been extensively studied. In some instances, 3D fluoroscopic navigation methods have been reported to not be more accurate than 2D navigation methods for pedicle screw placement. The authors of this study endeavored to identify if 3D fluoroscopic navigation methods resulted in a higher placement accuracy of pedicle screws. Methods A systematic analysis was conducted to examine pedicle screw insertion accuracy based on the use of 2D, 3D, and conventional fluoroscopic image guidance systems. A PubMed and MEDLINE database search was conducted to review the published literature that focused on the accuracy of pedicle screw placement using intraoperative, real-time fluoroscopic image guidance in spine fusion surgeries. The pedicle screw accuracy rates were segregated according to spinal level because each spinal region has individual anatomical and morphological variations. Descriptive statistics were used to compare the pedicle screw insertion accuracy rate differences among the navigation methods. Results A total of 30 studies were included in the analysis. The data were abstracted and analyzed for the following groups: 12 data sets that used conventional fluoroscopy, 8 data sets that used 2D fluoroscopic navigation, and 20 data sets that used 3D fluoroscopic navigation. These studies included 1973 patients in whom 9310 pedicle screws were inserted. With conventional fluoroscopy, 2532 of 3719 screws were inserted accurately (68.1% accuracy); with 2D fluoroscopic navigation, 1031 of 1223 screws were inserted accurately (84.3% accuracy); and with 3D fluoroscopic navigation, 4170 of 4368 screws were inserted accurately (95.5% accuracy). The accuracy rates when 3D was compared with 2D fluoroscopic navigation were also consistently higher throughout all individual spinal levels. Conclusions Three-dimensional fluoroscopic image guidance systems demonstrated a significantly higher pedicle screw placement accuracy than conventional fluoroscopy or 2D fluoroscopic image guidance methods.

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Utility of intraoperative electromyography in placing C7 pedicle screws

Journal of Neurosurgery Spine ◽

10.3171/2019.11.spine191120 ◽

2020 ◽

Vol 32 (6) ◽

pp. 891-899 ◽

Cited By ~ 1

Author(s):

Jonathan J. Rasouli ◽

Brooke T. Kennamer ◽

Frank M. Moore ◽

Alfred Steinberger ◽

Kevin C. Yao ◽

...

Keyword(s):

Cervical Spine ◽

Pedicle Screw ◽

Thoracolumbar Spine ◽

Pedicle Screws ◽

Neurological Injury ◽

Screw Placement ◽

Pedicle Screw Placement ◽

Data Set ◽

Subaxial Cervical Spine ◽

Increased Risk

OBJECTIVEThe C7 vertebral body is morphometrically unique; it represents the transition from the subaxial cervical spine to the upper thoracic spine. It has larger pedicles but relatively small lateral masses compared to other levels of the subaxial cervical spine. Although the biomechanical properties of C7 pedicle screws are superior to those of lateral mass screws, they are rarely placed due to increased risk of neurological injury. Although pedicle screw stimulation has been shown to be safe and effective in determining satisfactory screw placement in the thoracolumbar spine, there are few studies determining its utility in the cervical spine. Thus, the purpose of this study was to determine the feasibility, clinical reliability, and threshold characteristics of intraoperative evoked electromyographic (EMG) stimulation in determining satisfactory pedicle screw placement at C7.METHODSThe authors retrospectively reviewed a prospectively collected data set. All adult patients who underwent posterior cervical decompression and fusion with placement of C7 pedicle screws at the authors’ institution between January 2015 and March 2019 were identified. Demographic, clinical, neurophysiological, operative, and radiographic data were gathered. All patients underwent postoperative CT scanning, and the position of C7 pedicle screws was compared to intraoperative neurophysiological data.RESULTSFifty-one consecutive C7 pedicle screws were stimulated and recorded intraoperatively in 25 consecutive patients. Based on EMG findings, 1 patient underwent intraoperative repositioning of a C7 pedicle screw, and 1 underwent removal of a C7 pedicle screw. CT scans demonstrated ideal placement of the C7 pedicle screw in 40 of 43 instances in which EMG stimulation thresholds were > 15 mA. In the remaining 3 cases the trajectories were suboptimal but safe. When the screw stimulation thresholds were between 11 and 15 mA, 5 of 6 screws were suboptimal but safe, and in 1 instance was potentially dangerous. In instances in which the screw stimulated at thresholds ≤ 10 mA, all trajectories were potentially dangerous with neural compression.CONCLUSIONSIdeal C7 pedicle screw position strongly correlated with EMG stimulation thresholds > 15 mA. In instances, in which the screw stimulates at values between 11 and 15 mA, screw trajectory exploration is recommended. Screws with thresholds ≤ 10 mA should always be explored, and possibly repositioned or removed. In conjunction with other techniques, EMG threshold testing is a useful and safe modality in determining appropriate C7 pedicle screw placement.

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Confirmation of accuracy/inaccuracy of lumbar pedicle screw placement using postoperative computed tomography

Surgical Neurology International ◽

10.25259/sni_290_2021 ◽

2021 ◽

Vol 12 ◽

pp. 518

Author(s):

Mohamed M. Arnaout ◽

Magdy O. ElSheikh ◽

Mansour A. Makia

Keyword(s):

Computed Tomography ◽

Lumbar Spine ◽

Pedicle Screw ◽

Pedicle Screws ◽

Operative Intervention ◽

Screw Placement ◽

Lumbar Spine Surgery ◽

Pedicle Screw Placement ◽

Lumbar Pedicle ◽

Ct Studies

Background: Transpedicular screws are extensively utilized in lumbar spine surgery. The placement of these screws is typically guided by anatomical landmarks and intraoperative fluoroscopy. Here, we utilized 2-week postoperative computed tomography (CT) studies to confirm the accuracy/inaccuracy of lumbar pedicle screw placement in 145 patients and correlated these findings with clinical outcomes. Methods: Over 6 months, we prospectively evaluated the location of 612 pedicle screws placed in 145 patients undergoing instrumented lumbar fusions addressing diverse pathology with instability. Routine anteroposterior and lateral plain radiographs were obtained 48 h after the surgery, while CT scans were obtained at 2 postoperative weeks (i.e., ideally these should have been performed intraoperatively or within 24–48 h of surgery). Results: Of the 612 screws, minor misplacement of screws (≤2 mm) was seen in 104 patients, moderate misplacement in 34 patients (2–4 mm), and severe misplacement in 7 patients (>4 mm). Notably, all the latter 7 (4.8% of the 145) patients required repeated operative intervention. Conclusion: Transpedicular screw insertion in the lumbar spine carries the risks of pedicle medial/lateral violation that is best confirmed on CT rather than X-rays/fluoroscopy alone. Here, we additional found 7 patients (4.8%) who with severe medial/lateral pedicle breach who warranting repeated operative intervention. In the future, CT studies should be performed intraoperatively or within 24–48 h of surgery to confirm the location of pedicle screws and rule in our out medial or lateral pedicle breaches.

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Anatomical and radiologic characteristics of isthmus parameters in guiding pedicle screw placement

Journal of International Medical Research ◽

10.1177/0300060518762986 ◽

2018 ◽

Vol 46 (6) ◽

pp. 2386-2397 ◽

Cited By ~ 1

Author(s):

Paerhati Rexiti ◽

Yakufu Abulizi ◽

Aikeremujiang Muheremu ◽

Shuiquan Wang ◽

Maierdan Maimaiti ◽

...

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Screw Placement ◽

Lumbar Spine Surgery ◽

X Rays ◽

Pedicle Screw Placement ◽

Chinese Han ◽

Before And After ◽

Placement Accuracy ◽

D Value

Objective To study the clinical application of lumbar isthmus parameters in guiding pedicle screw placement. Methods Lumbar isthmus parameters were measured in normal lumbar x-rays and cadaveric specimens from a Chinese Han population. Distance between the medial pedicle border and lateral isthmus border was recorded as a ‘D’ value and was compared between X-rays and cadavers. Orthopaedic surgeons estimated different distances (2–6 mm) and angles (5–20°), and bias ratios between estimated and real values were compared. Orthopaedic residents placed pedicle screws on cadaveric specimens before and after application of the ‘D’ value, and screw placement accuracy was compared. Results Except for L4 vertebrae, significant differences in the ‘D’ value were found between 25 cadaveric specimens and x-ray films from 120 patients. Distances and angles estimated by 40 surgeons were significantly different from all real values, except 2 mm distance. Accuracy of pedicle screw placement by six orthopaedic residents was significantly improved by applying the ‘D’ value. Conclusions Surgeon estimates of distance were more accurate than angle estimates. Addition of a ‘D’ value to conventional parameters may significantly improve pedicle screw placement accuracy in lumbar spine surgery.

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A Novel Augmented-Reality-Based Surgical Navigation System for Spine Surgery in a Hybrid Operating Room: Design, Workflow, and Clinical Applications

Operative Neurosurgery ◽

10.1093/ons/opz236 ◽

2019 ◽

Vol 18 (5) ◽

pp. 496-502 ◽

Cited By ~ 18

Author(s):

Erik Edström ◽

Gustav Burström ◽

Rami Nachabe ◽

Paul Gerdhem ◽

Adrian Elmi Terander

Keyword(s):

Augmented Reality ◽

Radiation Exposure ◽

Pedicle Screw ◽

Operating Room ◽

Wound Closure ◽

Surgical Navigation ◽

Pedicle Screws ◽

Screw Placement ◽

Hybrid Operating Room ◽

Pedicle Screw Placement

Abstract BACKGROUND Treatment of several spine disorders requires placement of pedicle screws. Detailed 3-dimensional (3D) anatomic information facilitates this process and improves accuracy. OBJECTIVE To present a workflow for a novel augmented-reality-based surgical navigation (ARSN) system installed in a hybrid operating room for anatomy visualization and instrument guidance during pedicle screw placement. METHODS The workflow includes surgical exposure, imaging, automatic creation of a 3D model, and pedicle screw path planning for instrument guidance during surgery as well as the actual screw placement, spinal fixation, and wound closure and intraoperative verification of the treatment results. Special focus was given to process integration and minimization of overhead time. Efforts were made to manage staff radiation exposure avoiding the need for lead aprons. Time was kept throughout the procedure and subdivided to reflect key steps. The navigation workflow was validated in a trial with 20 cases requiring pedicle screw placement (13/20 scoliosis). RESULTS Navigated interventions were performed with a median total time of 379 min per procedure (range 232-548 min for 4-24 implanted pedicle screws). The total procedure time was subdivided into surgical exposure (28%), cone beam computed tomography imaging and 3D segmentation (2%), software planning (6%), navigated surgery for screw placement (17%) and non-navigated instrumentation, wound closure, etc (47%). CONCLUSION Intraoperative imaging and preparation for surgical navigation totaled 8% of the surgical time. Consequently, ARSN can routinely be used to perform highly accurate surgery potentially decreasing the risk for complications and revision surgery while minimizing radiation exposure to the staff.

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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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