Background: Pseudarthrosis of Type II C2 odontoid fractures typically leads to displacement and subluxation resulting in canal compression/cervical myelopathy. Case Description: Here, we present a 43-year-old male who sustained cervical trauma 28 years ago. He now presented with an acute 10-day onset of quadriparesis attributed to a chronic malunion of an unstable type II odontoid fracture. He successfully underwent a circumferential decompression and fusion (e.g., warranting a trans-oral odontoidectomy followed by C1-C3 posterior fusion). Conclusion: Progressive cervical myelopathy attributed to a chronic malunion of a type II odontoid fracture may require circumferential decompression/stabilization (e.g., an anterior decompression with osteophyte resection and posterior C1-C3 spinal stabilization).