title: A systematic review of the use of expandable cages in the cervical spine.
abstract: Expandable vertebral body replacement cages (VBRs) have been widely used for reconstruction of the thoracolumbar spine following corpectomy. However, their use in the cervical spine is less common, and currently, no expandable cages on the market are cleared or approved by the US Food and Drug Administration for use in the cervical spine. The objective of this study was to perform a systematic review on the use of expandable cages in the treatment of cervical spine pathology with a focus on fusion rates, deformity correction, complications, and indications. A comprehensive Medline search was performed, and 24 applicable articles were identified and included in this review. The advantages of expandable cages include greater ease of implantation with less risk of damage to the end plate, less intraoperative manipulation of the device, and potentially greater control over lordosis. They may be particularly advantageous in cases with poor bone quality, such as patients with osteoporosis or metastatic tumors that have been radiated. However, there is a potential risk of overdistraction, which is increased in the cervical spine, their minimum height limits their use in cases with collapsed vertebra, and the amount of hardware in the expansion mechanism may limit the surface area available for fusion. The use of expandable VBRs are a valuable tool in the armamentarium for reconstruction of the anterior column of the cervical spine with an acceptable safety profile. Although expandable cervical cages are clearly beneficial in certain clinical situations, widespread use following all corpectomies is not justified due to their significantly greater cost compared to structural bone grafts or non-expandable VBRs, which can be utilized to achieve similar clinical outcomes.
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287. belder4@jhmi.edu.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Elder
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287.
authors.forename: Sheng-Fu
authors.initials: SF
authors.lastname: Lo
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kosztowski
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287.
authors.forename: C Rory
authors.initials: CR
authors.lastname: Goodwin
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287.
authors.forename: Ioan A
authors.initials: IA
authors.lastname: Lina
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287.
authors.forename: John E
authors.initials: JE
authors.lastname: Locke
authors.affiliation: Department of Neurosurgery, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD, USA, 21287.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Witham
mesh_terms: D002574:Cervical Vertebrae / Q000601:surgery*; D015194:Diffusion Chambers, Culture; D006801:Humans; D016268:Internal Fixators; D019635:Neurosurgical Procedures / Q000295:instrumentation*; D013123:Spinal Fusion
keywords: Biomechanics; Cervical corpectomy; Expandable cage; Supplemental fixation; Vertebral body replacement