Preliminary experience with the DOC dynamic cervical implant for the treatment of multilevel cervical spondylosis

Steinmetz, Michael P.; Warbel, Ann; Whitfield, Melvin D.; Bingaman, William

doi:10.3171/spi.2002.97.3.0330

Cited by 17 publications

(30 citation statements)

References 24 publications

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“…Mean sagittal Cobb angle was 9°b efore surgery, and 16.9°at last follow-up. Of note, the authors used precountered TMCs and a correction of 8°w as achieved resembling a similar curve correction reported in other series including 2-and 3-level surgeries [6,111]. With instrumented 3-level ACDF and hybrid reconstructions for the correction of postsurgical CK in 10 cases, Steinmetz et al [110] achieved a mean correction of 20°w ith a mean lordosis of 8°.…”

Section: Influence Of Cervical Lordosissupporting

confidence: 53%

“…Patients treated with CSplates in our series had a significant shorter follow-up compared to patients treated with NC-plates (P = 0.01). But, significant changes in construct geometry mainly occur early in clinical course within 3 months after surgery [23,28,36,49,111,126]. This was the case in eight of nine patients with NC-plates applied in our series.…”

Section: Biomechanical Considerationsmentioning

confidence: 65%

“…Standing plain lateral radiographs obtained before and after index procedure, at 3-4 months, and at last follow-up visits were subsequently used to quantify changes in cervical lordosis and geometry of the fusion construct. Our study protocol determined a minimum follow-up of 6 months on basis of prior experience demonstrating that significant changes in construct geometry occur within about 3 months after surgery [23,28,36,49,111,126]. We evaluated geometrical changes in sagittal plane and cervical lordosis with the widespread technique of Harrison et al [38,44,111,113,123], using the angle formed between the tangential lines on the posterior edge of the vertebral bodies C2-7.…”

Section: Methodsmentioning

confidence: 99%

“…This observation might play a crucial role, in which restoration of a lordotic curvature is favourable, balances the sagittal profile, and prevents further kyphosis with possible implant loosening and neurologic deterioration. With respect to our series with only two poor clinical outcomes and a significant reduction of myelopathia scores postoperatively, we also consider the reconstruction of cervical lordosis, at least beyond 0°, a decisive factor for a good clinical outcome [12,110,111].…”

Section: Influence Of Cervical Lordosismentioning

confidence: 98%

“…However, a Halo vest was applied for six weeks with a semirigid collar for additional four weeks, and the time of recumbency was not given. Anterior instrumentations showed that the Halo can be despansible these days, but displaying their own biomechanical limits as part of anterior-only constructs: Steinmetz et al [111] reported on the results of 13 2-level and six 3-level ACDF, as well as four 1-level, nine 2-level, and two 3-level corpectomies using dynamic CS-plates. 2-and 3-level corpectomies showed union in 89 and 50%, respectively.…”

Section: Clinical Failures In Multilevel Anterior Cervical Constructsmentioning

confidence: 99%

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4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

et al. 2007

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In the future, there will be an increased number of cervical revision surgeries, including 4-and more-levels. But, there is a paucity of literature concerning the geometrical and clinical outcome in these challenging reconstructions. To contribute to current knowledge, we want to share our experience with 4-and 5-level anterior cervical fusions in 26 cases in sight of a critical review of literature. At index procedure, almost 50% of our patients had previous cervical surgeries performed. Besides failed prior surgeries, indications included degenerative multilevel instability and spondylotic myelopathy with cervical kyphosis. An average of 4.1 levels was instrumented and fused using constrained (26.9%) and non-constrained (73.1%) screw-plate systems. At all, four patients had 3-level corpectomies, and three had additional posterior stabilization and fusion. Mean age of patients at index procedure was 54 years with a mean follow-up intervall of 30.9 months. Preoperative lordosis C2-7 was 6.5°in average, which measured a mean of 15.6°at last follow-up. Postoperative lordosis at fusion block was 14.4°in average, and 13.6°at last follow-up. In 34.6% of patients some kind of postoperative change in construct geometry was observed, but without any catastrophic construct failure. There were two delayed unions, but finally union rate was 100% without any need for the Halo device. Eleven patients (42.3%) showed an excellent outcome, twelve good (46.2%), one fair (3.8%), and two poor (7.7%). The study demonstrated that anterior-only instrumentations following segmental decompressions or use of the hybrid technique with discontinuous corpectomies can avoid the need for posterior supplemental surgery in 4-and 5-level surgeries. However, also the review of literature shows that decreased construct rigidity following more than 2-level corpectomies can demand 360°instrumentation and fusion. Concerning construct rigidity and radiolographic course, constrained plates did better than non-constrained ones. The discussion of our results are accompanied by a detailed review of literature, shedding light on the biomechanical challenges in multilevel cervical procedures and suggests conclusions.

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Section: Influence Of Cervical Lordosissupporting

confidence: 53%

Section: Biomechanical Considerationsmentioning

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Influence Of Cervical Lordosismentioning

confidence: 98%

Section: Clinical Failures In Multilevel Anterior Cervical Constructsmentioning

confidence: 99%

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4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

et al. 2007

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Pitfalls in Cervical Spine Surgery

Denaro¹,

D’Avella²,

Denaro³

2010

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Cervical anterior transpedicular screw fixation. Part I: Study on morphological feasibility, indications, and technical prerequisites

et al. 2008

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Multilevel cervical spine procedures can challenge the stability of current anterior cervical screw-and-plate systems, particularly in cases of severe three-column subaxial cervical spine injuries and multilevel plated reconstructions in osteoporotic bone. Supplemental posterior instrumentation is therefore recommended to increase primary construct rigidity and diminish early failure rates. The increasing number of successfully performed posterior cervical pedicle screw fixations have enabled more stable fixations, however most cervical pathologies are located anteriorly and preferably addressed by an anterior approach. To combine the advantages of the anterior approach with the superior biomechanical characteristics of cervical pedicle screw fixation, the authors developed a new concept of a cervical anterior transpedicular screw-and-plate system. An in vivo anatomical study was performed to explore the feasibility of anterior transpedicular screw fixation (ATPS) in the cervical spine. The morphological study was conducted based on 29 cervical spine CT scans from healthy patients and measurements were performed on the pedicle sizes, angulations, vertebral body depth, height and width at C2 to T1. Significant morphologic parameters for the new technique are discussed. These parameters include the sagittal and transverse intersection points of the pedicle axis with the anterior vertebral body wall, as well as the distances between sagittal intersection points from C2 to T1. On the basis of these results, standard spine models were reconstructed and used for the conceptual development of a preclinical release prototype of an anterior transpedicular screw-and-plate system. The morphological feasibility of the new technique is demonstrated, and its indications, biomechanical considerations, as well as surgical prerequisites are thoroughly discussed. In the future, the technique of cervical anterior transpedicular screw fixation might diminish the number of failures in the reconstruction of multilevel and three-column cervical spine instabilities, and avoid the need for supplemental posterior instrumentation.

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Preliminary experience with the DOC dynamic cervical implant for the treatment of multilevel cervical spondylosis

Cited by 17 publications

References 24 publications

4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

Pitfalls in Cervical Spine Surgery

Cervical anterior transpedicular screw fixation. Part I: Study on morphological feasibility, indications, and technical prerequisites

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