Prevalence and Anatomy of Aberrant Right Subclavian Artery Evaluated by Computed Tomographic Angiography at a Single Institution in Korea

OBJECTIVE: Aberrant right subclavian artery (ARSA) is a rare anatomical variant of the origin of the right subclavian artery. ARSA is defined as the right subclavian artery originating as the final branch of the aortic arch. The purpose of this study is to determine the prevalence and the anatomy of ARSA evaluated with computed tomography (CT) angiography. METHODS: CT angiography was performed in 3460 patients between March 1, 2014 and November 30, 2015 and the results were analyzed. The origin of the ARSA, course of the vessel, possible inadvertent ARSA puncture site during subclavian vein catheterization, Kommerell diverticula, and associated vascular anomalies were evaluated. We used the literature to review the clinical importance of ARSA. RESULTS: Seventeen in 3460 patients had ARSA. All ARSAs in 17 patients originated from the posterior aspect of the aortic arch and traveled along a retroesophageal course to the right thoracic outlet. All 17 ARSAs were located in the anterior portion from first to fourth thoracic vertebral bodies and were located near the right subclavian vein at the medial third of the clavicle. Only one of 17 patients presented with dysphagia. CONCLUSION: It is important to be aware ARSA before surgical approaches to upper thoracic vertebrae in order to avoid complications and effect proper treatment. In patients with a known ARSA, a right transradial approach for aortography or cerebral angiography should be changed to a left radial artery or transfemoral approach.

Prevalence and Anatomy of Aberrant Right Subclavian Artery Evaluated by Computed Tomographic Angiography at a Single Institution in Korea

OBJECTIVE: Aberrant right subclavian artery (ARSA) is a rare anatomical variant of the origin of the right subclavian artery. ARSA is defined as the right subclavian artery originating as the final branch of the aortic arch. The purpose of this study is to determine the prevalence and the anatomy of ARSA evaluated with computed tomography (CT) angiography.METHODS: CT angiography was performed in 3460 patients between March 1, 2014 and November 30, 2015 and the results were analyzed. The origin of the ARSA, course of the vessel, possible inadvertent ARSA puncture site during subclavian vein catheterization, Kommerell diverticula, and associated vascular anomalies were evaluated. We used the literature to review the clinical importance of ARSA.RESULTS: Seventeen in 3460 patients had ARSA. All ARSAs in 17 patients originated from the posterior aspect of the aortic arch and traveled along a retroesophageal course to the right thoracic outlet. All 17 ARSAs were located in the anterior portion from first to fourth thoracic vertebral bodies and were located near the right subclavian vein at the medial third of the clavicle. Only one of 17 patients presented with dysphagia.CONCLUSION: It is important to be aware ARSA before surgical approaches to upper thoracic vertebrae in order to avoid complications and effect proper treatment. In patients with a known ARSA, a right transradial approach for aortography or cerebral angiography should be changed to a left radial artery or transfemoral approach.

A Type 1 Persistent Proatlantal Artery Originating from the External Carotid Artery Detected by Computed Tomographic Angiography

A persistent proatlantal artery (PA) is rare. We report a type 1 persistent PA originating from the right external carotid artery (ECA). A 78-year-old woman presented with dizziness. Computed tomographic (CT) angiography showed a persistent PA originating from the right ECA. This persistent PA did not pass through the atlas transverse foramen. The extracranial segment of this artery in the atlas transverse process level had a more lateral position than a normal left vertebral artery. CT angiography well demonstrated the relationship with bony structures and the course of this persistent PA. This anomalous artery in our patient presented as an incidental finding. Surgeon should recognize a persistent PA when performing carotid endarterectomy or ligation of the ECA for avoidance of complication.

Implementation and Outcomes of a Critical Pathway for Lumbar Laminectomy or Microdiscectomy

OBJECTIVE: The aim of this study is to implement a critical pathway (CP) for patients undergoing lumbar laminectomy or microdiscectomy and describe the results before and after the CP in terms of length of hospital stay and cost. METHODS: From March 2008 to February 2009, 61 patients underwent lumbar laminectomy or microdiscectomy due to stenosis or one- or two-level disc herniation in our department and were included in the prepathway group. After development and implementation of the CP in March 2009, 58 patients were applicable for the CP, and these were classified as the postpathway group. RESULTS: The CP, which established a 6-day hospital stay (5 bed-days), was fulfilled by 42 patients (72.4%) in the postpathway group. The mean length of stay was 5.4 days in the postpathway group compared to 6.9 days in the prepathway group, demonstrating a 20% reduction, which was a statistically significant difference (p< or =0.000). There was a statistically significant reduction in charges for bed and nursing care (p=0.002). CONCLUSION: Implementation of a CP for lumbar laminectomy or microdiscectomy produced significant decreases in length of hospitalization and charges for bed and nursing care. We believe that this CP reduces the unnecessary use of hospital resources without increasing risk of adverse events.

Cerebellar Liponeurocytoma with an Unusually Aggressive Histopathology : Case Report and Review of the Literature

We report a rare case of cerebellar liponeurocytoma with an unusually aggressive histopathology. A 49-year-old man presented with a four-month history of headache, vertigo, and progressive swaying gait. Magnetic resonance imaging showed a 3x3.5 cm sized relatively well-demarcated round mass lesion in the fourth ventricle, characterized by high signal intensity on T2-weighted images. Postcontrast images revealed strong enhancement of the solid portion and the cyst wall. The patient underwent suboccipital craniectomy and tumor removal. The pathologic diagnosis was cerebellar liponeurocytoma. Adjuvant radiotherapy was offered due to concerns related to the high proliferative index (Ki-67, 13.68%) of the tumor. At the last routine postoperative follow-up visit (12 months), the patient complained of no specific symptom and there was no evidence of tumor recurrence. However, long-term follow-up and the analysis of similar cases are necessary because of the low number of reports and the short follow-up of cases.

Dystrophic Calcification in the Epidural and Extraforaminal Space Caused by Repetitive Triamcinolone Acetonide Injections

The authors report a case of epidural and extraforaminal calcification caused by repetitive triamcinolone acetonide injections. A 66-year-old woman was admitted presenting with lower extremity weakness and radiating pain in her left leg. Ten months before admission, the patient was diagnosed as having an L4-5 spinal stenosis and underwent anterior lumbar interbody fusion followed by posterior fixation. Her symptoms had been sustained and she did not respond to transforaminal steroid injections. Repetitive injections (10 times) had been performed on the L4-5 level for six months. She had been taking bisphosphonate as an antiresorptive agent for ten months after surgery. Calcification in the ventral epidural and extraforaminal space was detected. The gritty particles were removed during decompressive surgery and these were proven to be a dystrophic calcification. The patient recovered from weakness and radiating leg pain. Repetitive triamcinolone acetonide injections after discectomy may be the cause of dystrophic calcification not only in the degenerated residual disc, but also in the posterior longitudinal ligament. Possible mechanisms may include the toxicity of preservatives and the insolubility of triamcinolone acetonide. We should consider that repetitive triamcinolone injections in the postdisectomy state may cause intraspinal ossification and calcification.

Spinal Intradural Extramedullary Cavernoma Presenting with Intracranial Superficial Hemosiderosis

A case of intradural extramedullary cavernous angioma is presented with headache, dizziness, and bilateral sensorineural hearing loss caused by an intracranial superficial hemosiderosis. It was incidentally found in a patient with a 3-month history of sustained headache, dizziness and a 3-year history of hearing difficulty. The neurological examination was unremarkable in the lower extremity. MR images showed an intracranial superficial hemosiderosis mostly in the cerebellar region. Myelography and MR images of the thoracolumbar spine revealed an intradural extramedullary mass, which was pathologically proven to be a cavernous angioma. T12 total laminoplastic laminotomy and total tumor removal were performed without any neurologic deficits. The patient's symptoms, including headache and dizziness, have been absent for three years. Intradural extramedullary cavernous angioma can present with an intracranial superficial hemosiderosis as a result of chronic subarachnoid hemorrhage.

Chordoid Glioma of the Third Ventricle with Unusual MRI Features

Chordoid glioma is a rare primary brain tumor of the third ventricle, and was recently characterized as a novel tumor entity. Typical radiological features of chordoid gliomas include; a solid, round-to-ovoid, wellcircumscribed, contrast-enhancing mass of the hypothalamus and anterior third ventricle. Despite being classified as WHO grade 2, the third ventricular chordoid glioma has been reported to have a poor clinical outcome because of its anatomical location. The authors report a case of chordoid glioma of the third ventricle in a 48-year-old man with unusual radiological features of cystic component and ill defined circumscription.

Falx Meningiomas: Surgical Results and Lessons Learned from 68 Cases

OBJECTIVE: The purpose of this study was to review the characteristics of falcine meningioma retrospectively and to identify the parameters associated with tumor recurrence. METHODS: The analysis included; age, sex, extent of resection, and radiologic and pathologic findings. Falcine meningiomas were classified by location as anterior, middle, or posterior as described for parasagittal meningiomas. RESULTS: Of the 795 meningioma patients treated between 1990 and 2004 at the authors' institution, 68 patients with meningiomas arising from the falx underwent craniotomies. There were 22 male and 46 female patients (1 : 2.1). Mean age was 55 years and ranged from 14 to 77 years. Locations of falcine meningioma were; the anterior third in 33 cases, middle in 20, and posterior in 15. Mean tumor volume was 42 cc and ranged from 4 to 140 cc. In 58 of the 68 patients tumors were totally removed. Additional surgery for recurrence was performed in 6 patients over 15 years. Of these 6 patients, only two patients underwent gross total tumor resection at first operation; the other four underwent subtotal tumor resection. Based on pathologic reports, the largest tumor subtype was transitional. There were four patients with a high grade tumor-three atypical and one anaplastic meningioma. Of the 68 patients, 59 achieved a good outcome (no neurological deficit or recurrence), six had temporary complications, two suffered new permanent postoperative deficits, and the remaining one died due to severe brain swelling despite postoperative intensive care. Extent of surgical resection was found to be significantly related to tumor recurrence. CONCLUSION: Falcine meningioma accounted for 8.5% of intracranial meningiomas and the transitional meningioma was the most common subtype of falcine meningioma. Gross total resection of tumor was the single most important predictor of an improved surgical outcome.