Elsevier

World Neurosurgery

Volume 97, January 2017, Pages 189-198
World Neurosurgery

Original Article
Use of a Zero-Profile Device for Contiguous 2-Level Anterior Cervical Diskectomy and Fusion: Comparison with Cage with Plate Construct

https://doi.org/10.1016/j.wneu.2016.09.065Get rights and content

Background

A new zero-profile, standalone device (Zero P) was recently developed and has shown a lower incidence rate of complications and competitive clinical outcomes compared with anterior cervical cage with plate construct (CP) in single and multilevel anterior cervical diskectomy and fusion (ACDF). However, there is still concern whether Zero P is appropriate for multilevel ACDF. In addition, there have been few reports of contiguous 2-level ACDF used in conjunction with Zero P.

Methods

We reviewed contiguous 2-level ACDF performed from December 2006 to February 2015. A total of 63 patients met inclusion criteria for the study (CP group = 32 cases; Zero P group = 31 cases). All preoperative and postoperative clinical and radiologic parameters were recorded. These parameters were compared between both groups.

Results

The postoperative change of Cobb S over time in the Zero P group was significantly different from that in the CP group. The maintenance of Cobb S in the Zero P group was better than that in the CP group (P < 0.05). The maintenance of anterior intervertebral disk height (IDH) at postoperative assessment for the Zero P group was significantly better than that in the CP group (P < 0.05). Within-group comparison of the postoperative change of anterior and posterior IDH over time revealed that the anterior IDH was significantly lower than the posterior IDH in the Zero P group (P < 0.05).

Conclusion

For 2-level contiguous ACDF, the use of a zero-profile device has the capacity to show compatible outcomes in correction and maintenance of segmental angle if the anterior titanium alloy plate is properly positioned at the anterior vertebral line.

Introduction

Anterior cervical diskectomy and fusion (ACDF) is generally been accepted as the gold standard surgical treatment for patients with cervical disk disease.1 It is important to reestablish stable load-bearing, maintain intervertebral disk height, and improve cervical lordosis for anterior cervical reconstruction and fusion. Anterior cervical cage with plate construct (CP) has been widely used in ACDF because it improves clinical outcomes, stability, fusion rate, and correction of lordosis.1, 2 Use of a plate construct may prevent graft dislocation and cage subsidence and confer segmental stability until bony fusion. However, it may also cause complications such as dysphasia, tracheoesophageal injury, or plate malposition.

Accordingly, application of a standalone cage has been used in conjunction with ACDF.3, 4, 5, 6 Although standalone cages have demonstrated clinical outcomes nearly equal to those of CP,7, 8, 9, 10 they have also been associated with a low-fusion rate, high subsidence rate, and difficulty maintaining cervical lordosis.6, 11

A new zero-profile, standalone device (Zero P; Synthes GmbH, Zuchwil, Switzerland) was recently developed to reduce the complications of traditional cervical plate construct while maintaining the benefits of interbody cages with plate construct. Zero P is composed of a radiolucent polyetheretherketone (PEEK) cage integrated with an anterior titanium plate containing 4 holes with screw treads that allow for fixation directly through the end plate. Zero P has a compact shape that allows for minimal volume between the anterior cervical body and soft tissue beneath the esophagus and trachea. Moreover, Zero P requires a smaller dissection compared with a traditional plate construct, which makes the device less prone to complications.

Recent reports documenting the use of Zero P for single-level and multilevel ACDF have shown a low incidence rate of complications, especially dysphasia, and competitive clinical and radiologic outcomes compared with CP.12, 13, 14, 15, 16, 17, 18 However, some clinicians still have questions whether Zero P is appropriate for multilevel ACDF because it has not been proven superior to CP for correction of cervical alignment and prevention of subsidence.19, 20 There are few reports regarding the efficacy of zero-profile devices for ACDF that focus on only 2 contiguous levels. The aim of this study is to compare zero-profile and CP devices for the treatment of contiguous 2-level ACDF.

Section snippets

Patient Population

Data were collected retrospectively for contiguous 2-level ACDF for degenerative cervical disk disease from December 2006 to February 2015 at a single institution. Patients suffering from symptoms of radiculopathy and/or myelopathy were included in the study. Radiologic findings corresponded to clinical manifestations and physical examinations.

Exclusion criteria were as follows: a history of previous cervical operation; follow-up period <6 months; radiologic parameters that could not be

Demographic and Surgical Data

The cases included 32 patients in the CP group and 31 patients in the Zero P group. Most operations occurred at C5/6, 6/7 in both groups and were not significantly different (P = 0.185). There was no significant difference between the 2 groups in terms of kyphotic changes (P = 0.936), which were evaluated preoperatively by lateral plain radiograph. The operation time for the Zero P group was significantly shorter than that of the CP group (P = 0.043). Demographic factors were not significantly

Discussion

During the past several decades, there has been a significant evolution in devices used for ACDF. Anterior cervical plating and cage insertion have been widely used. Cage insertion with plate construct has benefits for maintenance of mechanical stability, prevention of cage displacement, and increase of fusion rate.1 However, some reports have noted that plate construct for ACDF involves complications. In particular, the rate of complications may increase in ≥2-level ACDF.3, 4, 5, 6

To insert a

Conclusion

Use of a zero-profile device could be a useful option in contiguous 2-level ACDF. On the basis of our results, the most important aspect of Zero P usage is proper inserting position. An improvement in maintenance of the cervical angle and intervertebral disk height might be expected if the titanium alloy plate in Zero P is positioned well in the anterior vertebral line at the cortical corner of the cranial and caudal anterior cervical body at the disk level. To confirm this result, a long-term

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    Conflict of interest statement: This study was supported by a grant from the Spine Health Wooridul Hospital. None of the authors of this paper has a financial or personal relationship with other people or organizations that could inappropriately influence or bias the content of the paper.

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