**5.2 Surgical approach and discectomy**

The cervical hybrid arthroplasty is performed in the supine position under general anesthesia. A transverse incision in line with the planned arthroplasty level is employed for two- or three- level hybrid procedures (**Figure 2a**). Alternatively a longitudinal incision can be used for a more extensive procedure such as a multilevel procedure requiring corpectomies at the fusion level. Implantation of the arthroplasty always demands optimal visualization and therefore the incision should be inline with the proposed arthroplasty interspace while taking into consideration both the trajectory needed and the requisite instrumentation (**Figure 2b**). With that in mind following the skin incision, a standard Anterior Smith Robinson approach provides sufficient access to whichever interspace the surgeon plans to address first. After complete discectomy the endplates are denuded of all cartilaginous tissue with curettage prior to removal of any posterior uncinates or bone spurs. Prior to its removal the posterior longitudinal ligament is inspected for any tears or defects, which may give rise to sequestered fragments causing impingement on the thecal sac or neuroforamina. Once the discectomy has been performed care should be taken to remove any anterior or posterior osteophytes in order to contour the interspace inline with the proposed implant, and in doing so ensure a secure fit.

### **5.3 Measuring intraoperative depth**

The width and depth of the intended arthroplasty can be assessed prior to even selecting a trial with the placement of an intraoperative ruler (**Figure 3a, b**, **Video 1**). Predetermination of the dimensions of the trial for the arthroplasty can easily be attained in this manner and thereby avoids catastrophic implant or trial related complications and consequences [42].
