Joong Uhn Choi

Bio: Joong Uhn Choi is an academic researcher from Yonsei University. The author has contributed to research in topics: Epilepsy & Medulloblastoma. The author has an hindex of 16, co-authored 57 publications receiving 953 citations. Previous affiliations of Joong Uhn Choi include University Health System.

Endoscopic approach to arachnoid cyst.

Abstract: A prospective study of 36 consecutive patients with congenital arachnoid cysts treated endoscopically is reported. There were 15 female and 21 male patients. The mean age at the time of diagnosis was 12.3 years (10 days to 38 years). Arachnoid cysts were located in the suprasellar region in 16 patients, the sylvian fissure in 11, the quadrigeminal cistern in 4 and the posterior fossa in 5. Endoscopic fenestration was combined with cysto-peritoneal shunting for 6 temporal cysts and with ventriculo-peritoneal shunting in 1 suprasellar cyst. Mean postoperative follow-up was 4.2 years (range 1-8 years). Follow-up imaging studies showed that 28 arachnoid cysts (77.8%) were obliterated after endoscopic procedures. Long-term clinical results were good in all patients, although the cysts of 8 patients were not reduced in size. There was no mortality or morbidity. We conclude that endoscopic procedures may be a promising alternative to microsurgical operations or shunting for the treatment of arachnoid cysts.

Endoscopic surgery for obstructive hydrocephalus.

Abstract: Endoscopic surgery is popular in the neurosurgical field. The purpose of this study was to determine the role of endoscopy in obstructive hydrocephalus. From 1989 to 1999, we performed 81 endoscopic third ventriculostomies and 10 septostomies. Seventy-one of 81 operations were performed with endoscopic third ventriculostomy alone and 10 patients had endoscopic third ventriculostomy and ventriculoperitoneal shunt simultaneously. Age distribution varied from 2 months to 62 years of age. Our selection criteria included aqueductal stenosis (39 patients) and obstructive hydrocephalus due to tumor or cyst (42 patients). The most common candidate for endoscopic septostomy was atresia of the foramen of Monro (4 patients). Endoscopic septostomy was also performed to simplify shunting in patient; with multiseptated ventricle due to shunt infection, germinoma, thalamic tumor, craniopharyngioma, cyst and brain abscess. Sixty-five of 71 patients who were treated with endoscopic third ventriculostomy alone showed successful results (91.5%). However, 6 patients had unsatisfactory results and they needed a ventriculoperitoneal shunt. With no mortality, transient surgical complications were observed in 7 patients: 2 transient diabetes insipidus from electrical injury to the pituitary stalk, 1 epidural hematoma from sudden drainage of CSF, 1 delayed intraventricular hemorrhage. 2 obstruction of fenestration site and 1 transient memory disturbance from injury to the fornix. Endoscopic septostomy was useful in simplifying shunting in all cases with complicated hydrocephalus. Endoscopic surgery is straightforward and effective in appropriately selected cases with obstructive by drocephalus.

Treatment of germ cell tumors in the pineal region

Abstract: The authors retrospectively analyzed 107 patients with primary intracranial germ cell tumor (GCT), who were treated at the Department of Neurosurgery, Yonsei Medical Center between January 1986 and January 1996. The incidence of GCT was 2.8% in pediatric patients with intracranial tumor. Of the 107 tumors, 60 were located in the pineal region, 30 in the suprasellar region, 16 in basal ganglia or the thalamic region, and 1 in the posterior fossa. The 60 pineal GCT consisted of 39 germinomas (29 pure germinomas, 6 germinomas with STGC, 4 germinomas mixed with teratoma), 5 mature teratomas, and 16 nongerminomatous GCT. Thirty patients underwent surgery: their operations took the form of total resection in 14 cases, subtotal resection in 10, and biopsy in 6. Thirty patients (27 with germinomas, 3 with endodermal sinus tumors) were managed without surgery on the basis of radiological findings and tumor markers. The 5-year survival was 91% for 39 patients with germinomas, 80% for 5 with mature teratomas, and 49% for 16 with nongerminomatous GCT. Univariate analysis of prognostic factors with the Kaplan-Meier survival curve showed that histological tumor type, radiological findings, results of tumor marker studies, and response to trial radiation or chemotherapy were highly correlated with outcome. Chemotherapy was beneficial as the method of trial treatment in pineal GCT and treatment in recurrent tumors. The administration of trial chemotherapy or radiotherapy without tissue biopsy is well justified as a treatment modality in pineal GCT suspected on the basis of radiological findings and tumor marker studies. Aggressive multimodality approaches with surgery, radiotherapy, and chemotherapy are necessary to improve the outcome in these tumors. We propose new protocol for treatment of germ cell tumors in the pineal region, which is based on a minimally invasive approach.

Endoscopic disconnection for hypothalamic hamartoma with intractable seizure. Report of four cases.

Abstract: Although intractable epilepsy associated with hypothalamic hamartoma (HH) can be controlled by microsurgical resection of the lesion, excision of deep-seated lesions is often associated with morbidity and mortality. Endoscopic disconnection is less invasive and seems to be well suited for this indication. The authors discuss the role of endoscopic-assisted surgery in the management of HH-induced seizures. Four patients with HH-related intractable gelastic seizure underwent endoscopic disconnection surgery. Postoperatively, all patients exhibited improvement. Two patients became seizure free immediately after endoscopic disconnection surgery, one patient with a widespread seizure focus involving the motor strip continued to experience rare complex partial seizures but gelastic seizures ceased, and one experienced a reduced frequency of seizures but persistence of some generalized seizures. Three patients suffered postoperative disconnection-like syndrome, which continued 3 to 7 days and spontaneously disappeared. The authors advocate the endoscopic disconnection surgery as a safe and effective treatment for HH-related epilepsy by blocking the spread of epileptic discharges from the lesion.

Moyamoya Disease and Moyamoya Syndrome

Abstract: Moyamoya disease is a cerebrovascular condition predisposing affected patients to stroke in association with progressive stenosis of the intracranial internal carotid arteries and their proximal branches. Patients with characteristic moyamoya vasculopathy plus associated conditions are categorized as having moyamoya syndrome. This review describes the demographic characteristics, pathogenesis, evaluation, and treatment of moyamoya disease and syndrome.

Moyamoya disease: current concepts and future perspectives

Abstract: Moyamoya disease is an uncommon cerebrovascular disease that is characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The disease is associated with the development of dilated, fragile collateral vessels at the base of the brain, which are termed moyamoya vessels. The incidence of moyamoya disease is high in east Asia, and familial forms account for about 15% of patients with this disease. Moyamoya disease has several unique clinical features, which include two peaks of age distribution at 5 years and at about 40 years. Most paediatric patients have ischaemic attacks, whereas adult patients can have ischaemic attacks, intracranial bleeding, or both. Extracranial-intracranial arterial bypass, including anastomosis of the superficial temporal artery to the middle cerebral artery and indirect bypass, can help prevent further ischaemic attacks, although the beneficial effect on haemorrhagic stroke is still not clear. In this Review, we summarise the epidemiology, aetiology, clinical features, diagnosis, surgical treatment, and outcomes of moyamoya disease. Recent updates and future perspectives for moyamoya disease will also be discussed.

Management of Stroke in Infants and Children A Scientific Statement From a Special Writing Group of the American Heart Association Stroke Council and the Council on Cardiovascular Disease in the Young

Abstract: Purpose— The purpose of this statement is to review the literature on childhood stroke and to provide recommendations for optimal diagnosis and treatment. This statement is intended for physicians ...

Balancing repair and tolerance of DNA damage caused by alkylating agents

Abstract: Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity.

Balancing repair and tolerance of DNA damage caused by alkylating agents

Abstract: Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity.