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Chapter 19: Cervical Distraction and Stabilization 177

Figure 19.13 Radiographic follow‐up of a Great Dane after distraction/stabilization at C6–C7 with monocortical screw/PMMA fixation and cortical ring
allograft disc spacer. (A, B) Immediate postoperative orthogonal radiographs showing the fixation with triangular screw pattern and placement parallel to
the endplates. (C) Lateral radiograph 2 months postoperatively. The cortical ring has shifted slightly within the disc space compared with (A); however, fit
of the ring appears excellent at this time. (D) Lateral radiograph 2 year postoperatively. There is evidence of bony fusion across the mid to ventral aspect of
the disc space. Implants are intact and appear stable.

can occur during aggressive approaches or negligent use of tissue continued chronic pain and dysfunction, or it can acutely dislodge
retractors to access the ventral aspect of the vertebral column. causing sudden‐onset pain, radiculopathy, or myelopathy. Deep
Implant failure typically occurs by failure of the bone–screw inter- infection after surgical fixation is rare and would require implant
face, shearing of locking screws, or by cracking of the cement. It is removal. In case of screw/PMMA fixation, cement is removed
unusual for screws to shear at the screw–cement interface. While around screws using a pneumatic drill. Filling screw heads with
an intervertebral spacer aids in maintaining disc space distraction sterile bone wax prior to PMMA application will make screw
and helps with load sharing, it can be improperly placed, leading to removal easier. Postoperative seroma formation can occur if drill