**1. Introduction**

Spine surgeons and patients together are confronted with several surgical options when managing cervical pains which have not responded to conservative treatment options. Multilevel cervical disc pathology is defined as two or more segments of the cervical spine that have herniated, or degenerated, which are subsequently causing significant axial pain with radiculopathy, resulting in disability and a loss of productivity. Anterior cervical discectomy and fusion (ACDF) is considered the gold standard treatment for multilevel cervical spondylosis. However there are some long term drawbacks involving the development of subsidence, pseudarthrosis and the degeneration of adjacent segments [1–4]. Cervical artificial disc replacement (C-ADR) has been demonstrated to be a safe and effective means of treating single-level or multilevel cervical disc pathology by several prospective studies from the United States Food and Drug Administration and by some meta-analyses [5–11]. In patients who have multilevel pathology, there is a growing enthusiasm towards definitive management in the form of a cervical hybrid arthroplasty [12–15]. The cervical hybrid arthroplasty is a procedure wherein an artificial disc replacement can be placed at one level, with a cervical fusion device implanted at another nearby injured disc (**Figure 1**).


*2.1.1 Machined surfaces (smooth)*

Machined implants with an untreated surface are considered to have a smooth surface. Machined implants with an untreated surface are considered to have a smooth surface. However, they have small grooves that allow the bone mineralization process towards the implant, but they do not have an osteoinductive surface. This type of surface is considered anisotropic, which is responsible for promoting the cell adhesion process and the production of the protein matrix. The machined implant has a surface roughness between 0.5 μm and 1 μm. This smooth surface is formed a surficial microgroove, resulting from the machining process, produced by the passage of the cutting tool. This type of surface does not receive chemical or mechanical treatment, presenting only the micromorphology of the machining process [9]. **Figure 3** shows representative images of a smooth surface at different magnifications.


**Transition Metal Catalyzed Cross-Coupling Reactions**

Editor

**Ioannis D. Kostas**

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*Editor* Ioannis D. Kostas Institute of Chemical Biology National Hellenic Research Foundation Athens Greece

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