Magnetic resonance imaging artifact following anterior cervical discectomy and fusion with a trabecular metal cage

OBJECT This study was undertaken to evaluate the impact of postoperative MRI artifact on the assessment of ongoing spinal cord or nerve root compression after anterior cervical discectomy and fusion (ACDF) using a trabecular tantalum cage or bone autograft or allograft. METHODS The authors conducted a retrospective review of postoperative MRI studies of patients treated surgically for cervical disc degenerative disease or cervical instability secondary to trauma. Standard ACDF with either a trabecular tantalum cage or interbody bone graft had been performed. Postoperative MR images were shown twice in random order to each of 3 assessors (2 spine surgeons, 1 neuroradiologist) to determine whether the presence of a tantalum interbody cage and/or anterior cervical fixation plate or screws imparted MRI artifact significant enough to prevent reliable postoperative assessment of ongoing spinal cord or nerve root compression. RESULTS A total of 63 patients were identified. One group of 29 patients received a tantalum interbody cage, with 13 patients (45%) undergoing anterior plate fixation. A second group of 34 patients received bone auto- or allograft, with 23 (68%) undergoing anterior plate fixation. The paramagnetic implant construct artifact had minimal impact on visualization of postoperative surgical level spinal cord compression. In the cage group, 98% (171/174) of the cases were rated as assessable versus 99% in the bone graft group (201/204), with high intraobserver reliability. In contrast, for the assessment of ongoing surgical level nerve root compression, the presence of a tantalum cage significantly decreased visualization of nerve roots to 70% (121/174) in comparison with 85% (173/204) in the bone graft group (p < 0.001). When sequences using turbo spin echo (TSE), a T2-weighted axial sequence, were acquired, nerve roots were rated as assessable in 88% (69/78) of cases; when only axial T2-weighted sequences were available, the nerve roots were rated as assessable in 54% (52/96) of cases (p < 0.01). The presence of anterior plate fixation had minimal impact on visualization of the spinal cord (99% [213/216] for plated cases vs 98% [159/162] for nonplated cases; p = 1.0) or nerve roots (79% [170/216] for plated cases vs 77% [124/162] for nonplated cases; p = 0.62). CONCLUSIONS Interbody fusion with tantalum cage following anterior cervical discectomy imparts significant paramagnetic artifact, which significantly decreases visualization and assessment of ongoing surgical level nerve root, but not spinal cord, compression. Anterior plate constructs do not affect visualization of these structures. TSE T2-weighted sequences significantly improve nerve root visualization and should be performed as part of a standard postoperative protocol when imaging the cervical spine following interbody implantation of materials with potential for paramagnetic artifact.

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Comparative Study of Anterior Cervical Discectomy and Fusion by Cages versus Tricortical Bone Graft with Anterior Plate Fixation for Degenerative Cervical Disc Disease

International Journal of Clinical Studies and Medical Case Reports ◽

10.46998/ijcmcr.2020.06.000133 ◽

2020 ◽

Vol 6 (2) ◽

Author(s):

Anowarul Islam

Keyword(s):

Comparative Study ◽

Bone Graft ◽

Plate Fixation ◽

Anterior Cervical Discectomy ◽

Cervical Disc ◽

Cervical Disc Disease ◽

Anterior Plate ◽

Disc Disease ◽

Cervical Discectomy ◽

Degenerative Cervical Disc Disease

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Anterior Cervical Discectomy With Fusion and Plating for Correction of Degenerative Cervical Kyphosis: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opaa339 ◽

2020 ◽

Author(s):

Jeremy M V Guinn ◽

Brenton Pennicooke ◽

Joshua Rivera ◽

Praveen V Mummaneni ◽

Dean Chou

Keyword(s):

Spinal Cord ◽

Informed Consent ◽

Bone Density ◽

Surgical Intervention ◽

Anterior Cervical Discectomy ◽

Cervical Kyphosis ◽

Nerve Roots ◽

Cervical Discectomy ◽

Cervical Plate ◽

Sequential Induction

Abstract This surgical video demonstrates the technique for correcting degenerative cervical kyphosis using an anterior cervical discectomy and fusion (ACDF). Degenerative cervical kyphosis can cause radiculopathy, myelopathy, and difficulty holding up one's head. The goal of surgical intervention is to alleviate pain, improve the ability for upright gaze, and decompress the spinal cord or nerve roots. Posterior-only approaches and anterior corpectomies are alternative treatments to address cervical kyphosis. However, an ACDF allows for sequential induction of lordosis via distraction over multiple segments and for further lordosis induction by sequential screw tightening, pulling the spine towards a lordotic cervical plate.1 This video shows 2 cases demonstrating a technique of correcting severe cervical degenerative kyphosis. The video illustrates our initial kyphotic Caspar pin placement coupled with sequential anterior distraction to correct kyphosis. The technique is most useful in patients who have good bone density, nonankylosed facets, and degenerative cervical kyphosis. We have received informed consent of this patient to submit this video.

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Anterior cervical discectomy and fusion performed using structural allograft or polyetheretherketone: pseudarthrosis and revision surgery rates with minimum 2-year follow-up

Journal of Neurosurgery Spine ◽

10.3171/2019.9.spine19879 ◽

2020 ◽

Vol 32 (4) ◽

pp. 562-569

Author(s):

Minghao Wang ◽

Dean Chou ◽

Chih-Chang Chang ◽

Ankit Hirpara ◽

Yilin Liu ◽

...

Keyword(s):

Revision Surgery ◽

Plate Fixation ◽

Anterior Cervical Discectomy ◽

Anterior Plate ◽

Cervical Discectomy ◽

Posterior Surgery ◽

Structural Allograft ◽

Significant Difference ◽

Surgery Rates

OBJECTIVEBoth structural allograft and PEEK have been used for anterior cervical discectomy and fusion (ACDF). There are reports that PEEK has a higher pseudarthrosis rate than structural allograft. The authors compared pseudarthrosis, revision, subsidence, and loss of lordosis rates in patients with PEEK and structural allograft.METHODSThe authors performed a retrospective review of patients who were treated with ACDF at their hospital between 2005 and 2017. Inclusion criteria were adult patients with either PEEK or structural allograft, anterior plate fixation, and a minimum 2-year follow-up. Exclusion criteria were hybrid PEEK and allograft cases, additional posterior surgery, adjacent corpectomies, infection, tumor, stand-alone or integrated screw and cage devices, bone morphogenetic protein use, or lack of a minimum 2-year follow-up. Demographic variables, number of treated levels, interbody type (PEEK cage vs structural allograft), graft packing material, pseudarthrosis rates, revision surgery rates, subsidence, and cervical lordosis changes were collected. These data were analyzed by Pearson’s chi-square test (or Fisher’s exact test, according to the sample size and expected value) and Student t-test.RESULTSA total of 168 patients (264 levels total, mean follow-up time 39.5 ± 24.0 months) were analyzed. Sixty-one patients had PEEK, and 107 patients had structural allograft. Pseudarthrosis rates for 1-level fusions were 5.4% (PEEK) and 3.4% (allograft) (p > 0.05); 2-level fusions were 7.1% (PEEK) and 8.1% (allograft) (p > 0.05); and ≥ 3-level fusions were 10% (PEEK) and 11.1% (allograft) (p > 0.05). There was no statistical difference in the subsidence magnitude between PEEK and allograft in 1-, 2-, and ≥ 3-level ACDF (p > 0.05). Postoperative lordosis loss was not different between cohorts for 1- and 2-level surgeries.CONCLUSIONSIn 1- and 2-level ACDF with plating involving the same number of fusion levels, there was no statistically significant difference in the pseudarthrosis rate, revision surgery rate, subsidence, and lordosis loss between PEEK cages and structural allograft.

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