TO THE EDITOR
Re: Wang S, Wang C, Yan M, et al. Novel surgical classification and treatment strategy for atlantoaxial dislocations. Spine (Phila Pa 1976) 2013;38: E1348-56
We read with interest the recent article “Novel surgical classification and treatment strategy for atlantoaxial dislocations” by Wang et al.1 The authors are to be congratulated on designing the novel surgical classification and treatment strategy for atlantoaxial dislocations.
It is stated that, “If the presence of an osseous fusion between C1 and C2 was found on the reconstructive computed tomography scan, a classification of type IV was given.” According to his classification system (Figure 1), an odontoidectomy was recommended via a transoral approach. However, due to the lack of the gold standard for evaluating bony fusion in atlantoaxial joint, the disappearance of intra-articular space is deemed to be the sign of atlantoaxial bony fusion. We experienced a case with pseudo bony fusion on atlantoaxial joint, whose intra-articular space of left atlantoaxial joint was disappeared accompanying with significant sclerosis (Figure 2). A satisfactory reduction was acquired after intraoperative skull traction under general anesthesia (Figure 3). Hence, a fixation from C1 to C2 was enough via a single posterior approach.
Chronic atlantoaxial instability could lead to degenerated arthritis, fibrosis, or bony ankyloses, which is hard to be distinguished by computed tomography. We agree with Wang that intraoperative skull traction under general anesthesia could lead to total muscle curarization, which is necessary to achieve anatomical reduction. Due to the possibility of pseudo bony fusion, for the cases with suspected osseous fusion, we believe that an intraoperative traction test under general anesthesia is necessary, which could avoid the unnecessary anterior surgery.