scholarly journals Cortical bone facet spacers for cervical spine decompression: effects on intervertebral kinetics and foraminal area

2016 ◽  
Vol 24 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Christopher M. Maulucci ◽  
Charles A. Sansur ◽  
Vaneet Singh ◽  
Alexandra Cholewczynski ◽  
Snehal S. Shetye ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Cortical Bone ◽  
Posterior Instrumentation ◽  
Principal Component ◽  
Biomechanical Study ◽  
Nerve Roots ◽  
En Bloc ◽  
Cross Sectional ◽  
Subaxial Cervical Spine ◽  
Foraminal Area

OBJECT Nerve root decompression to relieve pain and radiculopathy remains one of the main goals of fusion-promoting procedures in the subaxial cervical spine. The use of allograft facet spacers has been suggested as a potential alternative for performing foraminotomies to increase the space available for the cervical nerve roots while providing segmental stiffening. Therefore, the goal of this cadaveric biomechanical study was to determine the acute changes in kinetics and foraminal area after the insertion of cortical bone facet spacers into the subaxial cervical spine. METHODS Allograft spacers (2 mm in height) were placed bilaterally into cadaveric cervical spine specimens (C2-T1, age of donors 57.5 ± 9.5 years, n = 7) at 1 (C4–5) and 3 (C3–6) levels with and without laminectomies and posterior lateral mass screw fixation. Standard stereophotogrammetry under pure moment loading was used to assess spinal kinetics. In addition, the authors performed 3D principal component analysis of CT scans to determine changes in foraminal cross-sectional area (FCSA) available for the spinal nerve roots. RESULTS Generally, the introduction of 2-mm-height facet spacers to the cervical spine produced mild, statistically insignificant reductions in motion with particular exceptions at the levels of implantation. No significant adjacent-level motion effects in any bending plane were observed. The addition of the posterior instrumentation (PI) to the intact spines resulted in statistically significant reductions in motion at all cervical levels and bending planes. The same kinetic results were obtained when PI was added to spines that also had facet spacers at 3 levels and spines that had been destabilized by en bloc laminectomy. The addition of 2-mm facet spacers at C3–4, C4–5, and C5–6 did produce statistically significant increases in FCSA at those levels. CONCLUSIONS The addition of allograft cervical facet spacers should be considered a potential option to accomplish indirect foraminal decompression as measured in this cadaveric biomechanical study. However, 2-mm spacers without supplemental instrumentation do not provide significantly increased spinal segmental stability.

scholarly journals Computed Tomography- and Radiography-Based Morphometric Analysis of the Lateral Mass of the Subaxial Cervical Spine in the Indian Population

2018 ◽  
Vol 12 (1) ◽  
pp. 18-28
Author(s):  
Nirmal D Patil ◽  
Sudhir K Srivastava ◽  
Sunil Bhosale ◽  
Shaligram Purohit
Keyword(s):  
Computed Tomography ◽  
Cervical Spine ◽  
Indian Population ◽  
Tertiary Care ◽  
X Rays ◽  
Lateral Mass ◽  
Cross Sectional ◽  
X Ray ◽  
Subaxial Cervical Spine ◽  
Screw Length

<sec><title>Study Design</title><p>This was a double-blinded cross-sectional study, which obtained no financial support for the research.</p></sec><sec><title>Purpose</title><p>To obtain a detailed morphometry of the lateral mass of the subaxial cervical spine.</p></sec><sec><title>Overview of Literature</title><p>The literature offers little data on the dimensions of the lateral mass of the subaxial cervical spine.</p></sec><sec><title>Methods</title><p>We assessed axial, sagittal, and coronal computed tomography (CT) cuts and anteroposterior and lateral X-rays of the lateral mass of the subaxial cervical spine of 104 patients (2,080 lateral masses) who presented to a tertiary care public hospital (King Edward Memorial Hospital, Mumbai) in a metropolitan city in India.</p></sec><sec><title>Results</title><p>For a majority of the parameters, males and females significantly differed at all levels (<italic>p</italic>&lt;0.05). Females consistently required higher (<italic>p</italic>&lt;0.05) minimum lateral angulation and lateral angulation. While the minimum lateral angulation followed the order of C5&lt;C4&lt;C6&lt;C3, the lateral angulation followed the order of C3&lt;C5&lt;C4&lt;C6. The lateral mass becomes longer and narrower from C3 to C7. In axial cuts, the dimensions increased from C3 to C6. The sagittal cut thickness and diagonal length increased and the sagittal cut height decreased from C3 to C7. The sagittal cut height was consistently lower in the Indian population at all levels, especially at the C7 level, as compared with the Western population, thereby questioning the acceptance of a 3.5-mm lateral mass screw. A good correlation exists between X-ray- and CT-based assessments of the lateral mass.</p></sec><sec><title>Conclusions</title><p>Larger lateral angulation is required for Indian patients, especially females. The screw length can be effectively calculated by analyzing the lateral X-ray. A CT scan should be reserved for specific indications, and a caution must be exercised while inserting C7 lateral mass screws.</p></sec>

A Novel and Reproducible Classification of the Vertebral Artery in the Subaxial Cervical Spine

2019 ◽  
Vol 18 (6) ◽  
pp. 676-683
Author(s):  
Fabian Winter ◽  
Ichiro Okano ◽  
Stephan N Salzmann ◽  
Colleen Rentenberger ◽  
Jennifer Shue ◽  
...  
Keyword(s):  
At Risk ◽  
Cervical Spine ◽  
High Risk ◽  
Vertebral Artery ◽  
Intrarater Reliability ◽  
Cross Sectional ◽  
Cervical Spine Surgery ◽  
Subaxial Cervical Spine ◽  
Anterior Posterior

Abstract BACKGROUND An injury of the vertebral artery (VA) is one of the most catastrophic complications in the setting of cervical spine surgery. Anatomic variations of the VA can increase the risk of iatrogenic lacerations. OBJECTIVE To propose a novel and reproducible classification system that describes the position of the VA based on a 2-dimensional map on computed tomography angiographs (CTA). METHODS This cross-sectional retrospective study reviewed 248 consecutive CTAs of the cervical spine at a single academic institution between 2007 and 2018. The classification consists of a number that characterizes the location of the VA from the medio-lateral (ML) aspect of the vertebral body. In addition, a letter describes the VA location from the anterior-posterior (AP) aspect. The reliability and reproducibility were assessed by 2 independent raters on 200 VAs. RESULTS The inter- and intrarater reliability values showed the classification's reproducibility. The inter-rater reliability weighted κ-value for the ML aspect was 0.93 (95% CI: 0.93-0.93). The unweighted κ-value was 0.93 (95% CI: 0.86-1.00) for “at-risk” positions (ML grade ≥1), and 0.87 (95% CI: 0.75-1.00) for “high-risk” positions (ML grade ≥2). The weighted κ-value for the intrarater reliability was 0.94 (95% CI: 0.95-0.95). The unweighted κ-values for the intrarater reliability were 0.95 (95% CI: 0.91-0.99) for “at-risk” positions, and 0.87 (95% CI: 0.78-0.96) for “high-risk” positions. CONCLUSION The proposed classification is reliable, reproducible, and independent of individual anatomic size variations. The use of this novel grading system could improve the understanding and interdisciplinary communication about VA anomalies.

Cervical spinal metastasis: anterior reconstruction and stabilization techniques after tumor resection

2003 ◽  
Vol 15 (5) ◽  
pp. 1-7 ◽  
Author(s):  
James K. Liu ◽  
Ronald I. Apfelbaum ◽  
Bennie W. Chiles ◽  
Meic H. Schmidt
Keyword(s):  
Cervical Spine ◽  
Spinal Metastasis ◽  
Posterior Instrumentation ◽  
Tumor Resection ◽  
Spinal Metastases ◽  
Metastatic Tumor ◽  
Subaxial Cervical Spine ◽  
Bone Autograft ◽  
Anterior Reconstruction ◽  
Anterior Cervical Corpectomy

Object In a review of the literature, the authors provide an overview of various techniques that have evolved for reconstruction and stabilization after resection for metastatic disease in the subaxial cervical spine. Methods Reconstruction and stabilization of the cervical spine after vertebral body (VB) resection for metastatic tumor is an important goal in the surgical management of spinal metastasis. Generally, the VB defect is reconstructed with bone autograft or allograft, polymethylmethacrylate (PMMA), interbody spacers, and/or cages. In cases of PMMA-assisted reconstruction, internal devices are used to augment the fixation of PMMA. Stabilization is then achieved with anterior instrumentation, usually an anterior cervical locking plate. In some cases, posterior instrumentation may be necessary to supplement the anterior construct. Conclusions Anterior cervical corpectomy followed by reconstruction and stabilization is an effective strategy in the management of spinal metastases in patients.

scholarly journals Changes in foraminal area with anterior decompression versus keyhole foraminotomy in the cervical spine: a biomechanical investigation

2017 ◽  
Vol 27 (6) ◽  
pp. 620-626 ◽  
Author(s):  
Jacqueline Nguyen ◽  
Bryant Chu ◽  
Calvin C. Kuo ◽  
Jeremi M. Leasure ◽  
Christopher Ames ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Cervical Disc ◽  
Cross Sectional ◽  
Key Points ◽  
Biomechanical Investigation ◽  
Flexion Extension ◽  
Indirect Decompression ◽  
Pure Moment ◽  
Keyhole Foraminotomy ◽  
Foraminal Area

OBJECTIVEAnterior cervical discectomy and fusion (ACDF) with or without partial uncovertebral joint resection (UVR) and posterior keyhole foraminotomy are established operative procedures to treat cervical disc degeneration and radiculopathy. Studies have demonstrated reliable results with each procedure, but none have compared the change in neuroforaminal area between indirect and direct decompression techniques. The purpose of this study was to determine which cervical decompression method most consistently increases neuroforaminal area and how that area is affected by neck position.METHODSEight human cervical functional spinal units (4 each of C5–6 and C6–7) underwent sequential decompression. Each level received the following surgical treatment: bilateral foraminotomy, ACDF, ACDF + partial UVR, and foraminotomy + ACDF. Multidirectional pure moment flexibility testing combined with 3D C-arm imaging was performed after each procedure to measure the minimum cross-sectional area of each foramen in 3 different neck positions: neutral, flexion, and extension.RESULTSNeuroforaminal area increased significantly with foraminotomy versus intact in all positions. These area measurements did not change in the ACDF group through flexion-extension. A significant decrease in area was observed for ACDF in extension (40 mm2) versus neutral (55 mm2). Foraminotomy + ACDF did not significantly increase area compared with foraminotomy in any position. The UVR procedure did not produce any changes in area through flexion-extension.CONCLUSIONSAll procedures increased neuroforaminal area. Foraminotomy and foraminotomy + ACDF produced the greatest increase in area and also maintained the area in extension more than anterior-only procedures. The UVR procedure did not significantly alter the area compared with ACDF alone. With a stable cervical spine, foraminotomy may be preferable to directly decompress the neuroforamen; however, ACDF continues to play an important role for indirect decompression and decompression of more centrally located herniated discs. These findings pertain to bony stenosis of the neuroforamen and may not apply to soft disc herniation. The key points of this study are as follows. Both ACDF and foraminotomy increase the foraminal space. Foraminotomy was most successful in maintaining these increases during neck motion. Partial UVR was not a significant improvement over ACDF alone. Foraminotomy may be more efficient at decompressing the neuroforamen. Results should be taken into consideration only with stable spines.

scholarly journals The Subaxial Cervical AO Spine Injury Score

2020 ◽  
pp. 219256822097433
Author(s):  
Jose A. Canseco ◽  
Gregory D. Schroeder ◽  
Taylor M. Paziuk ◽  
Brian A. Karamian ◽  
Frank Kandziora ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Classification System ◽  
Cervical Spine Injury ◽  
Spine Injury ◽  
Cross Sectional Survey ◽  
Injury Score ◽  
Cross Sectional ◽  
Severity Rating ◽  
Subaxial Cervical Spine ◽  
Injury Classification

Study Design: Global cross-sectional survey. Objective: To develop an injury score for the AO Spine Subaxial Cervical Spine Injury Classification System. Methods: Respondents numerically graded each variable within the classification system for severity. Based on the results, and with input from the AO Spine Trauma Knowledge Forum, the Subaxial Cervical AO Spine Injury Score was developed. Results: An A0 injury was assigned an injury score of 0, A1 a score of 1, and A2 a score of 2. Given the significant increase in severity, A3 was given a score of 4. Based on equal severity assessment, A4 and B1 were both assigned a score of 5. B2 and B3 injuries were assigned a score of 6. Unstable C-type injuries were given a score of 7. Stable F1 injuries were assigned a score of 2, with a 2-point increase for F2 injuries. Likewise, F3 injuries received a score of 5, whereas more unstable F4 injuries a score of 7. Neurologic status severity rating scores increased stepwise, with scores of 0 for N0, 1 for N1, and 2 for N2. Consistent with the Thoracolumbar AO Spine Injury Score, N3 (incomplete) and N4 (complete) injuries were given a score of 4. Finally, case-specific modifiers M1 (PLC injury) received a score of 1, while M2 (critical disc herniation) and M3 (spine stiffening disease) received a score of 4. Conclusions: The Subaxial Cervical AO Spine Injury Score is an easy-to-use metric that can help develop a surgical algorithm to supplement the AO Spine Subaxial Cervical Spine Injury Classification System.

Total cervical spondylectomy for primary osteogenic sarcoma

2002 ◽  
Vol 97 (3) ◽  
pp. 386-392 ◽  
Author(s):  
Zvi R. Cohen ◽  
Daryl R. Fourney ◽  
Rex A. Marco ◽  
Laurence D. Rhines ◽  
Ziya L. Gokaslan
Keyword(s):  
Cervical Spine ◽  
Osteogenic Sarcoma ◽  
En Bloc Resection ◽  
Bloc Resection ◽  
Nerve Roots ◽  
En Bloc ◽  
Total En Bloc Spondylectomy ◽  
Content Type ◽  
Bloc Spondylectomy ◽  
Thoracic And Lumbar Spine

✓ The authors describe a technique for total spondylectomy for lesions involving the cervical spine. The method involves separately staged anterior and posterior approaches and befits the unique anatomy of the cervical spine. The procedure is described in detail, with the aid of radiographs, intraoperative photographs, and illustrations. Unlike in the thoracic and lumbar spine—for which methods of total en bloc spondylectomy have previously been described—a strictly en bloc resection is not possible in the cervical spine because of the need to preserve the vertebral arteries and the nerve roots supplying the upper limbs. Although the resection described in this case is by definition intralesional, it is oncologically sound, given the development of effective neoadjuvent chemotherapeutic regimens for osteosarcoma.

scholarly journals Treatment of Injuries to the Subaxial Cervical Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)

2018 ◽  
Vol 8 (2_suppl) ◽  
pp. 25S-33S ◽  
Author(s):  
Philipp Schleicher ◽  
Philipp Kobbe ◽  
Frank Kandziora ◽  
Matti Scholz ◽  
Andreas Badke ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cervical Spine ◽  
Facet Joint ◽  
Posterior Instrumentation ◽  
Pedicle Screws ◽  
German Society ◽  
Vertebral Body Replacement ◽  
Cervical Spine Injuries ◽  
Subaxial Cervical Spine ◽  
Spine Injuries

Study Design: Expert consensus. Objectives: To establish treatment recommendations for subaxial cervical spine injuries based on current literature and the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma. Methods: This recommendation summarizes the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma. Results: Therapeutic goals are a stable, painless cervical spine and protection against secondary neurologic damage while retaining maximum possible motion and spinal profile. The AOSpine classification for subaxial cervical injuries is recommended. The Canadian C-Spine Rule is recommended to decide on the need for imaging. Computed tomography is the favoured modality. Conventional x-ray is preserved for cases lacking a “dangerous mechanism of injury.” Magnetic resonance imaging is recommended in case of unexplained neurologic deficit, prior to closed reduction and to exclude disco-ligamentous injuries. Computed tomography angiography is recommended in high-grade facet joint injuries or in the presence of vertebra-basilar symptoms. A0-, A1- and A2-injuries are treated conservatively, but have to be monitored for progressive kyphosis. A3 injuries are operated in the majority of cases. A4- and B- and C-type injuries are treated surgically. Most injuries can be treated with anterior plate stabilization and interbody support; A4 fractures need vertebral body replacement. In certain cases, additive or pure posterior instrumentation is needed. Usually, lateral mass screws suffice. A navigation system is advised for pedicle screws from C3 to C6. Conclusions: These recommendations provide a framework for the treatment of subaxial cervical spine Injuries. They give advice about diagnostic measures and the therapeutic strategy.

The diagnostic accuracy of MRI and nonenhanced CT for high-risk vertebral artery anatomy for subaxial anterior cervical spine surgery safety

2021 ◽  
pp. 1-8
Author(s):  
Ichiro Okano ◽  
Stephan N. Salzmann ◽  
Fabian Winter ◽  
Erika Chiapparelli ◽  
Yushi Hoshino ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cervical Spine ◽  
High Risk ◽  
Diagnostic Accuracy ◽  
Vertebral Artery ◽  
Linear Regression Analysis ◽  
Preoperative Imaging ◽  
Cross Sectional ◽  
Subaxial Cervical Spine ◽  
Medial Migration

OBJECTIVE Medial migration of the vertebral artery (VA) can be a risk factor for injury during anterior procedures. CT angiography (CTA) has been considered the gold standard for the evaluation of various areas of the arterial anatomy. MRI and nonenhanced CT are more commonly used as routine preoperative imaging studies, but it is unclear if these modalities can safely exclude the anomalous course of the VA. The aims of this cross-sectional observational study were to investigate risk factors for medially migrated VA on CTA and to evaluate the diagnostic accuracy of MRI and nonenhanced CT for high-risk VA anatomy in the subaxial cervical spine. METHODS The records of 248 patients who underwent CTA for any reason at a single academic institution between 2007 and 2018 were reviewed. The authors included MRI and nonenhanced CT taken within 1 year before or after CTA. An axial VA position classification was used to grade VA anomalies in the subaxial cervical spine. The multivariable linear regression analysis with mixed models was performed to identify the risk factors for medialized VA. The sensitivity and specificity of MRI and nonenhanced CT for high-risk VA positions were calculated. RESULTS A total of 175 CTA sequences met the inclusion criteria. The mean age was 63.8 years. Advanced age, disc and pedicle levels, lower cervical levels, and left side were independent risk factors for medially migrated VA. The sensitivities of MRI and nonenhanced CT for the detection of grade 1 or higher VA position were only fair, and the sensitivity of MRI was lower than that of nonenhanced CT (0.31 vs 0.37, p < 0.001), but the specificities were similarly high for both modalities (0.97 vs 0.97). With the combination of MRI and nonenhanced CT, the sensitivity significantly increased to 0.50 (p < 0.001 vs MRI and vs CT alone) with a minimal decrease in specificity. CONCLUSIONS Axial images of MRI and nonenhanced CT demonstrated high specificities but only fair sensitivities. Nonenhanced CT demonstrated better diagnostic value than MRI. When combining both modalities the sensitivity improved, but a substantial proportion of medialized VAs could not be diagnosed.

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