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Jung Yong Ahn, Seong Oh Kwon, Moon Soo Shin, Jin Yang Joo and Tai Sung Kim

✓ Idiopathic trigeminal sensory neuropathy is a clinically benign disorder in which the main feature is facial numbness limited to the territory of one or more divisions of the trigeminal nerve; the disorder persists for a few weeks to several years, and no underlying disease can be identified. Magnetic resonance (MR) imaging findings are occasionally consistent with a small trigeminal neuroma of the left gasserian ganglion associated with idiopathic trigeminal sensory neuropathy. The authors report on two patients who were treated using a skull base approach in which the gasserian ganglion was exposed and the lesion was removed. The pathological diagnosis was chronic granulomatous neuritis. The authors conclude that, in patients with MR findings suggestive of a small trigeminal neuroma, benign idiopathic trigeminal sensory neuropathy should also be considered in the differential diagnosis. A conservative approach featuring sequential MR imaging studies may avoid an unnecessary surgical exploration.

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Jung Yong Ahn, Young Sun Chung and Byung-Hee Lee

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Yong Ahn, Sang-Ho Lee, Woo-Min Park and Ho-Yeon Lee

✓ The purpose of this study was to determine the efficacy and feasibility of posterolateral percutaneous endoscopic lumbar foraminotomy (PELF) for foraminal or lateral exit zone stenosis of the L5—S1 level in the awake patient.

Twelve consecutive patients with L5—S1 foraminal stenosis and associated leg pain underwent PELF between May 2001 and July 2002. Under fluoroscopic guidance, posterolateral endoscopic foraminal decompression was performed using a bone reamer, endoscopic forceps, and a laser. Using this new technique, the authors removed part of the hypertrophied superior facet, thickened ligamentum flavum, and protruded disc compressing the exiting (L-5) nerve root. Clinical outcome was measured using the Macnab criteria. The mean follow-up period was 12.9 months. All the patients were discharged within 24 hours. Satisfactory (excellent or good) results were demonstrated in 10 patients. There was no complication.

The PELF procedure provides a simple alternative for treating lumbar foraminal or lateral exit zone stenosis in selected cases. The authors found that the posterolateral endoscopic approach to the L5—S1 foramen was usually possible and that using a bone reamer to undercut the superior facet was effective.

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Sook Young Sim, Yong Sam Shin, Kyung Gi Cho, Sun Yong Kim, Se Hyuk Kim, Young Hwan Ahn, Soo Han Yoon and Ki Hong Cho

Object

The clinical features of blood blister–like aneurysms (BBAs) that arise at nonbranching sites of the internal carotid artery (ICA) differ from those of saccular aneurysms. In this study, the authors attempt to describe optimal treatments for BBAs, which have yet to be clearly established.

Methods

Ten of 483 patients with aneurysmal subarachnoid hemorrhage who had been seen at the authors’ institution between March 2001 and June 2005 had intraoperatively confirmed BBAs at nonbranching sites of the ICA. All ten patients were women between the ages of 37 and 64 years (mean age 49.3 years); five had a history of hypertension. The BBAs were localized to the right side of the ICA in seven cases. All patients were successfully treated; clipping was undertaken in six, clipping combined with wrapping in three, and trapping in one. These methods were used in conjunction with various other surgical techniques such as brain relaxation by draining cerebrospinal fluid, anterior clinoidectomy, exposing the cervical ICA, gentle subpial dissection (for aneurysms that adhered to the frontal lobe), complete trapping of the ICA before clipping, and protecting the brain. Clip slippage occurred at the end of dural closing in two cases; the aneurysm was completely obliterated using multiple clips combined with ICA stenosis in one of these cases and ICA trapping with good collateral flow in the other. An excellent clinical outcome was achieved in eight patients, whereas two patients were disabled from massive vasospasm. The authors retrospectively reviewed radiological and surgical data in all cases to determine which treatment methods produced a favorable outcome.

Conclusions

Blood blister–like aneurysms located at nonbranching sites of the ICA are difficult to treat. Preoperative awareness and careful consideration of these lesions during surgery can prevent poor clinical outcomes.

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Keun Young Park, Jung Yong Ahn, Jun Hyung Cho, Young Chul Choi and Kyu Sung Lee

✓Neuromyelitis optica (NMO) is a severe demyelinating syndrome defined principally by its tendency to affect optic nerves and the spinal cord selectively. Asymptomatic brain lesions have recently become a common finding in NMO, and symptomatic brain lesions do not exclude the diagnosis of this entity. The authors describe the case of a 12-year-old girl suffering from an unusually atypical form of NMO in which a brainstem lesion was mistaken for a brainstem glioma. Brainstem involvement in NMO exhibits variable features on neuroimaging and is confused with brainstem glioma in cases of extensive brainstem involvement in childhood. Careful differential diagnosis and proper treatment are vital for a favorable prognosis.

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So-Hyang Im, Moon Hee Han, Bae Ju Kwon, Jung Yong Ahn, Cheolkyu Jung, Sung-Hye Park, Chang Wan Oh and Dae Hee Han

Object

Considerable confusion exists in the literature regarding the classification of cerebrovascular malformations and their clinical significance. One example is provided by the atypical developmental venous anomaly (DVA) with arteriovenous shunt, because it remains controversial whether these lesions should be classified as DVAs or as atypical cases of other subtypes of cerebrovascular malformations. The purpose of this study was to clarify the classification of these challenging vascular lesions in an effort to suggest an appropriate diagnosis and management strategy.

Methods

The authors present a series of 15 patients with intracranial vascular malformations that were angiographically classified as atypical DVAs with arteriovenous shunts. This type of vascular malformation shows a fine arterial blush without a distinct nidus and early filling of dilated medullary veins that drain these arterial components during the arterial phase on angiography. Those prominent medullary veins converge toward an enlarged main draining vein, which together form the caput medusae appearance of a typical DVA.

Results

Based on clinical, angiographic, surgical, and histological findings, the authors propose classifying these vascular malformations as a subtype of an arteriovenous malformation (AVM), rather than as a variant of DVA or as a combined vascular malformation.

Conclusions

Correct recognition of this AVM subtype is required for its proper management, and its clinical behavior appears to follow that of a typical AVM. Gamma Knife radiosurgery appears to be a good alternative to resection, although long-term follow-up results require verification.

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Jun Hyung Cho, Jung Yong Ahn, Sung Uk Kuh, Dong Kyu Chin and Young Sul Yoon

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Yong Ahn, June Ho Lee, Ho-Yeon Lee, Sang-Ho Lee and Sang-Hyun Keem

Object

The purpose of this study was to evaluate the predictive factors for subsequent vertebral fracture occurring after percutaneous vertebroplasty (PVP) at the neighboring levels (adjacent vs nonadjacent levels).

Methods

The medical records of 508 consecutive patients treated with PVP between January 2000 and December 2002 were retrospectively reviewed. A total of 45 patients with 49 painful vertebral fractures occurring after PVP was identified based on clinical and radiological findings. New vertebral fractures, developing at any of the 3 consecutive vertebral bodies (VBs) above or below the previously treated level, were the focus of the study. The patients were divided into 3 groups: an adjacent-level fracture group, nonadjacent-level fracture group, and a control group composed of 50 randomly selected patients in whom there was no evidence of a new fracture. Clinical, imaging, and procedure-related factors for each group were statistically analyzed.

Results

In 31 patients 35 VBs were classified as adjacent-level fractures, and in 14 patients 14 VBs were classified as nonadjacent-level fractures. After further vertebroplasty, the overall pain intensity and satisfaction rate in patients with post-PVP fractures were similar to those in the control group. In cases involving adjacent fractures, lower body mass index and intradiscal cement leakage were the significant predictive factors of fracture. In contrast, lower mobility of the index segment was related to nonadjacent-level fracture.

Conclusions

According to the authors' results, the mechanisms of subsequent fracture at adjacent and nonadjacent vertebrae are different. A direct pillar effect (that is, the difference in strength caused by cement augmentation) may provoke an adjacent-level fracture, whereas a dynamic hammer effect (the difference in segmental mobility) may lead to a nonadjacent fracture.

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Keun Young Park, Jung Yong Ahn, Jae Whan Lee, Jong Hee Chang and Seung Kon Huh

Vascular complications, including vessel occlusion and hemorrhage, can arise after radiosurgery; however, hemorrhage due to a ruptured de novo aneurysm after Gamma Knife radiosurgery (GKS) for tumor is extremely rare. To the authors' knowledge, only a single case of de novo aneurysm formation after GKS for vestibular schwannoma has been previously reported. In this study, they describe their experience with the treatment of a 74-year-old woman with subarachnoid hemorrhage limited to the cerebellopontine cistern, who had undergone GKS for vestibular schwannoma 5 years earlier. Cerebral angiography demonstrated a left distal anterior inferior cerebellar artery aneurysm; coil embolization was attempted and failed. However, self-resolution of the aneurysm was revealed on follow-up angiography.

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Yong Ahn, Jin Uk Kim, Byung Hoi Lee, Sang-Ho Lee, Jong Dae Park, Dong Hyun Hong and June Ho Lee

Object

The purpose of this study was to demonstrate the clinical characteristics of postoperative retroperitoneal hematoma (RPH) following transforaminal percutaneous endoscopic lumbar discectomy (PELD) and to discuss how to prevent the complication of unintended hemorrhage.

Methods

The medical records of 412 consecutive patients treated with transforaminal PELD between January 2005 and May 2007 were reviewed. A total of 4 patients (0.97%) experienced symptomatic postoperative RPH. The clinical outcomes were evaluated using the visual analog scale and the Oswestry Disability Index.

Results

The common symptom in all patients with a hematoma was inguinal pain. The mean hematoma volume was 527.9 ml (range 53.3–1274.1 ml). Two patients with massive diffuse-type RPHs compressing the intraabdominal structures required open hematoma evacuation performed by general surgeons, and the other 2 patients with small, localized RPHs of < 100 ml were treated conservatively. The mean follow-up period was 21.3 months (range 13–29 months). The mean visual analog scale score for radicular leg pain improved from 7.6 to 1.8 and that for back pain improved from 4.3 to 2. The mean Oswestry Disability Index improved from 58.8 to 9.1%. The preoperative symptoms improved after the second treatment without significant neurological sequelae in all patients.

Conclusions

Although transforaminal PELD is a minimally invasive and safe procedure, the possibility of RPH should be kept in mind. Adequate technical and anatomical considerations are important to avoid this unusual hemorrhagic complication, especially in the patient with underlying medical problems or previous operative scarring. A high index of suspicion and early detection is also important to avoid the progression of the hematoma.