Utilization of Three-dimensional Reconstruction Computed Tomography as a Diagnostic Tool for Adult Unilateral Primary Cervical Spondylolysis: Report of Two Cases

Primary spontaneous cervical spondylolysis is a rare anomaly, and is often diagnosed as a traumatic lesion such as a fracture or a locked facet; alternatively, it may be overlooked. A literature review revealed one report that addresses the usefulness of three-dimensional reconstruction computed tomography (CT) imaging in the diagnosis of cervical spondylolysis. We have experienced two cases of subaxial cervical spondylolysis. One patient was transferred to our institute due to trauma, and the other patient was referred from a local hospital without trauma history. In this second patient symptoms occurred spontaneously and showed insidious progression. Both cases typically involved the right side of the C6 vertebra. The author utilized three-dimensional (3-D) reconstruction computed tomography (CT) for diagnosis and evaluation. Among those issued in Korea, this is the first report of primary subaxial cervical spondylolysis evaluated using 3-D CT.

Persistent Trigeminal Artery Variant Detected by Conventional Angiography and Magnetic Resonance Angiography: Incidence and Clinical Significance

OBJECTIVE: Persistent trigeminal artery variant (PTAV) is an anastomosis between the internal carotid artery (ICA) and the cerebellar artery without any interposing basilar artery segment. We discuss its probable embryological origin and emphasize clinical implications. METHODS: Retrospectively 1250 conventional cerebral angiograms and 2947 cranial magnetic resonance angiographies (MRAs) were evaluated for the patients with PTAV. RESULTS: Five patients (four men and one woman, 23 to 76 years of age, median age 65 years) had a PTAV. Three patients who underwent MRA had a PTAV (3/2947=0.1%). Four of the patients who underwent cerebral angiography had a PTAV (4/1250=0.32%). Two of 143 patients who underwent both conventional angiography and cranial MRA showed PTAV. The PTAV was an incidental finding in all five patients. The PTAV originated from the cavernous segment of the left ICA in four patients and from the cavernous segment of the right ICA in one patient. The terminal branch of the PTAV was the anterior inferior cerebellar artery (AICA) and superior cerebellar artery (SCA) in two patients and the AICA only in the other three patients. CONCLUSION: Neurosurgeons should be aware of possible presence of PTAV. Manipulation of this vessel during a surgical approach to the parasellar region and percutaneous gasserian ganglion procedure may result in hemorrhage or ischemia.