Distractive flexion injuries of the subaxial cervical spine treated with a posterior procedure using cervical pedicle screws or a combined anterior and posterior procedure

Object Lateral mass screws (LMS) have been used extensively with a low complication rate in the subaxial spine. Recently, cervical pedicle screws (CPS) have been introduced, and are thought to provide more optimal stabilization of the subaxial spine in certain circumstances. However, because of the concern for neurovascular injury, the routine use of CPS in this location remains controversial. Despite this controversy, however, there are no articles directly comparing screw-related complications of each procedure in the subaxial cervical spine. The purpose of this study was to evaluate screw-related complications of LMS and CPS in the subaxial cervical spine. Methods A PubMed/MEDLINE and Cochrane Collaboration Library search was executed, using the key words “lateral mass screw” and “cervical pedicle screw.” Clinical studies evaluating surgical procedures of the subaxial cervical spine in which either LMS or CPS were used and complications were reported were included. Studies in which the number of patients who had subaxial cervical spine surgery and the number of screws placed from C-3 to C-7 could not be specified were excluded. Data on screw-related complications of each study were recorded and compared. Results Ten studies of LMS and 12 studies of CPS were included in the analysis. Vertebral artery injuries were slightly but statistically significantly higher with the use of CPS relative to LMS in the subaxial cervical spine. Although the use of LMS was associated with a higher rate of screw loosening, screw pullout, loss of reduction, pseudarthrosis, and revision surgery, this finding was not statistically significant. Conclusions Based on the available literature, it appears that perioperative neurological and late biomechanical complication rates, including pseudarthrosis, are similarly low for both LMS and CPS techniques. In contrast, vertebral artery injuries, although statistically significantly more common when using CPS, are extremely rare with both techniques, which may justify their nonroutine use in select cases. Given the paucity of well-designed studies available, this recommendation may be a reflection of deficiencies in the available studies. Surgeons using either technique should have intimate knowledge of cervical anatomy and an adequate preoperative evaluation for each patient, with the final selection based on individual case requirements and anatomical limitations.

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Morphometric evaluation of subaxial cervical spine using multi-detector computerized tomography (MD-CT) scan: the consideration for cervical pedicle screws fixation

BMC Musculoskeletal Disorders ◽

10.1186/1471-2474-15-125 ◽

2014 ◽

Vol 15 (1) ◽

Cited By ~ 12

Author(s):

Pongsthorn Chanplakorn ◽

Chaiwat Kraiwattanapong ◽

Kitti Aroonjarattham ◽

Pittavat Leelapattana ◽

Gun Keorochana ◽

...

Keyword(s):

Cervical Spine ◽

Ct Scan ◽

Computerized Tomography ◽

Pedicle Screws ◽

Subaxial Cervical Spine ◽

Cervical Pedicle ◽

Cervical Pedicle Screws ◽

Morphometric Evaluation

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Subaxial Cervical Pedicle Screw Placement With Direct Visualization of Pedicle Borders: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opab086 ◽

2021 ◽

Author(s):

S Harrison Farber ◽

Michael A Bohl ◽

David S Xu ◽

Juan S Uribe ◽

U Kumar Kakarla ◽

...

Keyword(s):

Cervical Spine ◽

Pedicle Screws ◽

Tactile Feedback ◽

Screw Placement ◽

Direct Visualization ◽

Fusion Construct ◽

Subaxial Cervical Spine ◽

Loss Of Resistance ◽

Cervical Pedicle ◽

High Degree

Abstract Pedicle screws provide superior fixation of the subaxial cervical spine to other techniques. However, a high degree of accuracy is required for safe placement given the proximity of pedicles to critical neurovascular structures. A variety of techniques are described to maximize accuracy, including freehand, fluoroscopy-guided, and neuronavigation-based methods. We present a technique for the placement of pedicle screws in the subaxial cervical spine using direct visualization of the pedicle in a patient who required an occipito-cervical fusion construct in the setting of a C2 chordoma. A laminotomy or laminectomy is performed laterally to allow for visualization of the medial, superior, and inferior walls of the pedicle. The entry point for screw placement is determined based on pedicle anatomy and is typically 1 to 2 mm lateral to the midpoint of the lateral mass, just below the base of the superior articulating process. Screw trajectory is determined by visualizing the pedicle borders and is aimed at the junction of the medial pedicle wall, with the posterior vertebral body down the pedicle axis. Tactile feedback (loss of resistance) is used to assess for a breach while drilling. The cannulation is then tapped, and the screw is placed in a standard fashion. Direct visualization of pedicle anatomy can be a useful adjunct to guide the safe placement of subaxial pedicle screws when superior fixation is required or when normal anatomy is distorted. The technique may be combined with fluoroscopic or navigation-based techniques to provide real-time anatomic guidance during screw placement. The patient provided informed, written consent for this procedure before surgery. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

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The accuracy of a novel pedicle screw insertion technique assisted by a special angular scale in the subaxial cervical spine using lateral mass as a reference marker

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-020-02054-1 ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Hang Shi ◽

Lei Zhu ◽

Jun Ma ◽

Yu-Cheng Zhu ◽

Xiao-Tao Wu

Keyword(s):

Cervical Spine ◽

Pedicle Screws ◽

Ct Images ◽

Entry Point ◽

Lateral Mass ◽

Insertion Technique ◽

Reference Marker ◽

Subaxial Cervical Spine ◽

Angular Scale ◽

Cervical Pedicle

Abstract Background Posterior cervical pedicle screw (CPS) internal fixation has better biomechanical stability than other posterior cervical fixation methods. However, this technique is limited in clinical practice due to the complex anatomical structure and the adjacent relationship of the cervical pedicle, and the high risk of neurovascular injury. The purpose of this study was to describe a novel subaxial CPS insertion technique assisted by a special angular scale using lateral mass as a reference marker and to evaluate the accuracy of CPS placement and the distribution characteristics of CPS misplacement. Methods A total of 36 patients with subaxial cervical spine diseases who underwent posterior CPS fixation were consecutively selected. The optimal entry point on the posterior surface of the lateral mass was identified on the three-dimensional cervical model reconstructed from preoperative computed tomography (CT) images. The pedicle transverse angle (PTA) and pedicle-lateral mass angle (PLMA) were measured on the transverse and sagittal CT images respectively. The pedicle screws were inserted according to the preoperatively planned entry point and angles. We analysed the postoperative CT images for CPS misplacement rates and perforation directions following the Lee classification. Results Overall, 177 pedicle screws were inserted, of which 119 (67.2%) were classified as grade 0, 43 (24.3%) as grade 1, 12 (6.8%) as grade 2 and 3 (1.7%) as grade 3 by the postoperative CT images. The accuracy rate of CPS placement was 91.5%. Of the 15 misplaced pedicle screws (grades 2 and 3), 11 were lateral pedicle perforations, 3 were superior perforations and 1 was an inferior perforation. There were no neurovascular injuries related to CPS misplacement. Conclusions With our technique, the optimal entry point and two angles (PTA and PLMA) were identified for CPS insertion. The novel CPS insertion technique assisted by a special angular scale provides high accuracy and few complications.

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Patient-Matched 3-D-Printed Guides for the Insertion of Cervical Pedicle Screws in Tumor Surgery

Case Reports in Surgery ◽

10.1155/2021/8135996 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

C.-E. Heyde ◽

G. Osterhoff ◽

Spiegl UJA ◽

A. Völker ◽

N. H. von der Höh ◽

...

Keyword(s):

Cervical Spine ◽

Ct Scan ◽

Pedicle Screw ◽

Pedicle Screws ◽

Patient Specific ◽

Screw Insertion ◽

Pedicle Screw Insertion ◽

Intraoperative Fluoroscopy ◽

Cervical Pedicle ◽

Cervical Pedicle Screws

Background. Pedicle screw fixation in the cervical spine provides biomechanical advantages compared to other stabilization techniques. However, pedicle screw insertion in this area is challenging due to the anatomical conditions with a high risk of breaching the small pedicles and violating the vertebral artery or neural structures. Today, several techniques to facilitate screw insertion and to make the procedure safer are used. 3-D-printed patient-matched guides based on a CT reconstruction are a helpful technique which allows to reduce operation time and to improve the safety of pedicle screw insertion at the cervical spine. Cases. 3-D-printed patient-matched drill guides based on a CT scan with a 3-D reconstruction of the spine were used in two challenging cervical spine surgical tumor cases to facilitate the implantation of the pedicle screws. The screw position was controlled postoperatively by means of the routinely performed CT scan. Results. Postoperative imaging (conventional radiographs and CT scan) revealed the correct position of the pedicle screws. The time needed for screw insertion was short, and the need for intraoperative fluoroscopy could be reduced. There was no intra- or postoperative complication related to the pedicle screw implantation. Both tumors could be removed completely. Conclusion. These preliminary results show that 3-D-printed patient-specific guides are a promising tool to support and facilitate the implantation of cervical pedicle screws. The time needed for insertion is short, and intraoperative fluoroscopy time can be reduced. This technique allows for both a meticulous preoperative planning and a correct and therefore safe intraoperative positioning of cervical spine pedicle screws.

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Validation of Freehand Cervical Pedicle Screw Placement in Subaxial Spine Using the “Burcev Technique”: A Cadaveric Study

Journal of Neurosciences in Rural Practice ◽

10.1055/s-0041-1727410 ◽

2021 ◽

Author(s):

Mantu Jain ◽

Rabi N. Sahu ◽

Manisha R. Gaikwad ◽

Sashikanta Panda ◽

Amit Tirpude ◽

...

Keyword(s):

Horizontal Plane ◽

Sagittal Plane ◽

Pedicle Screws ◽

Continuous Variables ◽

Pedicle Screw Placement ◽

Cervical Pedicle Screw ◽

Freehand Technique ◽

Computed Tomography Scans ◽

Cervical Pedicle ◽

Cervical Pedicle Screws

AbstractThe present study attempted to validate the “Burcev freehand method” based on anatomical observations in Indian cadavers. The study was conducted on 32 cervical pedicle screws (CPSs) that were placed in four cadavers by the authors according to the “freehand technique,” described by Burcev et al, without the aid of fluoroscopy and the trajectory verified by computed tomography scans. The screws were designated as satisfactory, permissible, or unacceptable. Descriptive variables were represented in number and percentages, continuous variables were represented as mean ± standard deviation (SD). Of the 32 CPSs placed, 24 (75%) exhibited a satisfactory position, 1 (3%) exhibited a permissible position, and 7 (22%) exhibited an unacceptable position. Of the seven CPSs in the unacceptable group, four exhibited a lateral breach and three exhibited a medial breach, whereas the CPS in the permissible group exhibited a medial breach. The overall angle with contralateral lamina in the horizontal plane in terms of mean ± SD was 175.43 ± 2.82, 169.49, and 169.65 ± 6.46 degrees in the satisfactory, permissible, and unacceptable groups, respectively. In the sagittal plane, the screws exhibited an angle of 88.15 ± 3.56 degrees. No breach was observed superiorly or inferiorly. The “Burcev technique” is replicable with similar results in cadavers. Further studies must be conducted in a clinical setting to ensure its safety.

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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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