The Risk Factors of Subdural Hygroma after Decompressive Craniectomy / 대한신경손상학회지

OBJECTIVE: Subdural effusion, also known as subdural hygroma (SDG), is a secondary complication that can occur after decompressive craniectomy (DC). However, the pathogenesis of SDG is not fully understood. It is unclear whether SDG occurrence is related to preoperative patient status or surgical technique. The purpose of this study is to identify risk factors for SDG after DC. METHODS: Fifty-nine patients who underwent DC from January 2016 to December 2016 at the same institution were analyzed. We retrospectively reviewed the clinical and radiological features of the patients. We divided the patients into two groups based on the occurrence of SDG after DC. The risk factors for SDG were analyzed. RESULTS: The overall SDG rate after DC was 39% (23 patients). A statistically significant association was observed between preoperative diagnosis, e.g., subdural hemorrhage (SDH; odds ratio [OR], 4.99; 95% confidence interval [CI], 1.36–18.34) or subarachnoid hemorrhage (SAH; OR, 4.18; 95% CI, 1.07–16.32), and the occurrence of SDG after DC. Traumatic brain injury (OR, 4.91; 95% CI, 1.35–17.91) and preoperative cortical opening (OR, 4.77; 95% CI, 1.39–16.32) were important risk factors for SDG. Several surgical techniques did not show a statistically significant association with SDG. The occurrence of SDG after DC was related to the length of hospital stay (p=0.012), but not to prognosis. CONCLUSION: After DC, SDG is not related to patients' prognosis but to the length of hospital stay. Therefore, it is necessary to study the occurrence of postoperative SDG by confirming the presence of preoperative SDH, SAH, and cortical opening.

Factors Affecting Optimal Time of Cranioplasty: Brain Sunken Ratio / 대한신경손상학회지

OBJECTIVE: After a rigorous management of increased intracranial pressure by decompressive craniectomy (DC), cranioplasty (CP) is usually carried out for functional and cosmetic purposes. However, the optimal timing of CP remains controversial. Our study aims to analyze the relationship between the optimal timing of CP and the post-operative complications. METHODS: From January 2013 to December 2015, ninety patients who underwent CP in a single institution were analyzed. We set the independent variables as follows: 1) patient characteristics; 2) the time interval between the DC and CP; 3) operation time; 4) anesthesia time; and 5) pre-operative computed tomography (CT) findings such as a degree of sunken brain by ratio of A (the median length from scalp to midline) to B (the length from midline to inner table of skull at this level). The dependent variables of this study are the event of post-operative complications. RESULTS: The overall complication rate was 33.3%. There was no statistical significance in the time interval between the DC and CP in the groups with and without complications of CP (p=0.632). However, there was a significant statistical difference in the degree of sunken brain by ratio (A/B) between the two groups (p<0.001). CONCLUSION: From this study, we conclude that it is better to determine the optimal timing of CP by the pre-operative CT finding than by the time interval between the DC and CP. Hereby, we suggest a potentially useful determinant of optimal timing of CP.

Cranial Nerve Palsy after Onyx Embolization as a Treatment for Cerebral Vascular Malformation

The Onyx liquid embolic system is a relatively safe and commonly used treatment for vascular malformations, such as arteriovenous fistulas and arteriovenous malformations. However, studies on possible complications after Onyx embolization in patients with vascular malformations are limited, and the occurrence of cranial nerve palsy is occasionally reported. Here we report the progress of two different types of cranial nerve palsy that can occur after embolization. In both cases, Onyx embolization was performed to treat vascular malformations and ipsilateral oculomotor and facial nerve palsies were observed. Both patients were treated with steroids and exhibited symptom improvement after several months. The most common types of neuropathy that can occur after Onyx embolization are facial nerve palsy and trigeminal neuralgia. Although the mechanisms underlying these neuropathies are not clear, they may involve traction injuries sustained while extracting the microcatheter, mass effects resulting from thrombi and edema, or Onyx reflux into the vasa nervorum. In most cases, the neuropathy spontaneously resolves several months following the procedure.

Endovascular Treatment of Giant Serpentine Aneurysm of the Middle Cerebral Artery

Giant serpentine aneurysms are uncommon types of aneurysmal disease and have angiographically authentic features. We report a case of a 44-year-old male with headache and seizure. He presented a giant serpentine aneurysm arising from the middle cerebral artery (MCA). It was a large intracranial aneurysm thrombosed as a mass-like lesion while it maintained its outflow drainage into the distal MCA branches. The balloon occlusion test (BOT) was performed to test the tolerance of temporary collateral circulation. Following routine cerebral angiography, we performed an endovascular embolization on the proximal artery of MCA. He was discharged from the hospital with alert mental status and mild Gerstmann syndrome. The short-term follow-up imaging studies showed the decreased mass effect, and the patient presented an improved Gerstmann syndrome. After a careful evaluation of BOT, an endovascular embolization can be one of the powerful therapeutic instruments for giant serpentine aneurysm.

Clinical Analysis of Delayed Surgical Epidural Hematoma / 대한신경손상학회지

OBJECTIVE: A small epidural hematoma (EDH) that has been diagnosed to be nonsurgical by initial brain computed tomography (CT) can increase in size and need surgical removal, resulting in a poor prognosis. However, there have been few studies, which focused delayed operated EDH. Therefore, we analyzed the clinical factors to determine the predicting factors of delayed operated EDH. METHODS: Between January 2011 and January 2014, 90 patients, who were admitted due to EDH, were enrolled in this study. None of the patients were indicated for operation initially. Based on the presence of surgery, we classified the patients into a delayed-surgery group (DG) and a non-surgical group (NG). Additionally, we analyzed them according to the following: time interval between the trauma and the initial CT, gender, age, medical history, drinking, change of mean arterial pressure (MAP), volume of EDH and other traumatic brain lesion. RESULTS: Among the 90 patients, the DG was 19 patients. Compared with NG, the DG revealed increased MAP, less presence of drinking, and a short time interval (DG vs. NG: +9.684 mm Hg vs. -0.428 mm Hg, 5.26% vs. 29.58%, 1.802 hours vs. 5.707 hours, respectively, p<0.05). Analyzing the time interval with receiver operating characteristic, there was 88.2% sensitivity and 68.3% specificity at the 2.05-hour cut-off value (area under the curve=0.854). CONCLUSION: According to our results, the time interval between the trauma and the initial CT along with blood pressure change are potential predicting factors in the cases of delayed operation of EDH.

Retrieval of Unintended Migrated Detached Coil: Case Report

Owing to the rapid development of intervention techniques and devices, endovascular coil embolization of cerebral arteries has become standardized. It is particularly preferred when a patient presents with an unruptured intracranial aneurysm of the posterior communicating artery (PcomA). However, the risk of thrombogenic complications of the coil migration may also result in a large cerebral infarction. When coil migration occurs during embolization, a procedure for removal of the embolic coil should be performed immediately. We experienced a clinically rare case of migration of a framing coil to the distal middle cerebral artery aneurysm during endovascular embolization of an unruptured PcomA aneurysm. The migrated coil was barely retrieved using snare techniques.

Clinical Analysis of Risk Factors in Shunt-dependent Hydrocephalus after Aneurysmal Subarachnoid Hemorrhage / 대한뇌혈관외과학회지

OBJECTIVES: Shunt-dependent hydrocephalus is the major sequela after subarachnoid hemorrhage (SAH) and this continues to be a major source of morbidity for these patients. The prevalence and risk factors are not clear, despite the significant clinical and basic science research that's been done. We analyze the risk factors of shunt-dependent hydrocephalus such as the clinical and radiological parameters, the treatment modality and the peri-operative preparation. METHODS: We collected data on 475 patients with aneurysmal SAH and who were admitted to our hospital between January 1996 and January 2005. We retrospectively analyzed the age, gender, Hunt-Hess grade, Fisher grade, hypertension, intraventricular hemorrhage (IVH), rebleeding, vasospasm, location of aneurysm, treatment modality, timing of surgery, lumbar drainage, external ventricular drainage (EVD) and the prognosis as risk factors. RESULTS: 22.1% (105/475) of the aneurysmal SAH patients developed shunt-dependent hydrocephalus. Univariate analysis revealed that the patient's age, Hunt Hess grade, IVH, rebleeding, vasospasm, location of aneurysm, timing of operation, lumbar drainage, EVD and the prognosis had statistically significant correlation with the development of shunt-dependent hydrocephalus (p<0.05). Through multivariate regression analysis, the aneurysms located in the posterior circulation, use of lumbar drainage and the cases with acute hydrocephalus showed a high prevalence of shunt-dependent hydrocephalus. CONCLUSION: Among the numerous factors, only lumbar drainage was a partially controllable factor. Further analysis of the clinical factors associated with CSF drainage and re-evaluation of the indications for drainage are needed.

Angiographic Recurrence after Endovascular Coil Embolization for Intracranial Aneurysm / 대한뇌혈관외과학회지

OBJECTIVE: We have investigated the risk factors associated with angiographic recurrence of intracranial aneurysms after endovascular coil embolization in a retrospective manner. METHODS: From January 2000 to June 2005, 128 aneurysms in 114 patients were treated with coil embolization. Among them, 54 aneurysms in 51 patients were followed by repeated intraarterial angiography at 6, 12, 18, and 24 months post-embolization. Recurrence was defined when either coil compaction or aneurysm regrowth was identified on follow-up angiography. Patients were divided into stable and recurred groups according to angiographic recurrence. Clinical parameters, anatomical factors, and the degree of occlusion were retrospectively reviewed. RESULTS: The overall recurrence rate was 29% in our study. The diameter of the largest dimension of the fundus was larger in the recurred group of patients as compared to the stable group of patients (7.33+/-2.26 mm vs. 5.87+/-1.93mm, p = 0.048), and a significant rate of recurrence was seen in fundus size of the same or greater than 10 mm (41.7% vs 14.3%, p = 0.038). The coil packing density was significantly smaller in the recurred group of patients (p = 0.002), with a recurrence rate of 47.0% in cases with a coil packing density below 25% (p = 0.017). CONCLUSIONS: Our study showed that maximum aneurysm fundus size and coil packing density had a close correlation to recurrence. However, a larger number of patients with longer observation times may be needed to define the risk factors affecting angiographic recurrence.

The Usefulness of Contrast Extravasation on CT Angiography in Spontaneous Intracerebral Hemorrhage / 대한뇌혈관외과학회지

OBJECTIVE: The authors investigated the clinical and radiographic characteristics of patients who exhibited contrast extravasation on initial computed tomographic angiography (CTA) and assessed the its association with hematoma expansion. METHODS: Ninety six patients who were diagnosed with intracerebral hemorrhage and who received CTA within 12 hours from initial onset of symptoms and who received a follow up brain CT within 48 hours from the initial CTA between April 2004 and March 2007 were retrospectively assessed. Contrast extravasation was defined as the presence of high-density material within the hematoma. Patients were classified into the extravasation and no extravasation groups. Clinical and radiographic variables were compared between the two groups. RESULTS: Fifteen patients (19%) demonstrated presence of extravasation on initial CTA. A significantly higher rate of hematoma expansion was seen in the extravasation group compared to the non extravasation group (47% vs 17%, p=0.027). Mean time from onset of symptoms to initial CTA was significantly shorter in the extravasation group (3.5+/-1.3 hours vs 7.6+/-2.5 hours, p0.001). CONCLUSIONS: Earlier detection of extravasation using CTA may help in identifying possibly life threatening complications caused by hematoma expansion. However, a larger prospective cohort is warranted to validate this result.

Posttraumatic Carotid-cavernous fistula Combined with Intracavernous False Aneurysm / 대한뇌혈관외과학회지

Posttraumatic high-flow communications between the intracavernous internal carotid artery (ICA) and the cavernous sinus may give rise to two different pathological entities. A connection from the intracavernous ICA system can theoretically connect with two different structures; the vein of the plexus (CCF) or the perivascular bare spaces between the veins (pseudoaneurysm). A CCF and a pseudoaneurysm can be present in the same patient. A 24-year-old man was admitted to our hospital due to sudden mental deterioration. Carotid angiography revealed a CCF, which had occurred after a trauma 5 years earlier, associated with left visual disturbance and skull base fractures. The treatment of choice was permanent coil occlusion of the intracavernous ICA at the level of the lesion. The collateral circulation was evaluated before the endovascular treatment using a balloon test occlusion (BTO). During the BTO, adequate collateral circulation was defined as symmetric angiographic filling of both hemispheres. A continuous neurological examination was performed during the procedure. The follow-up angiography showed a persistent aneurysm occlusion. We report our experience of the successful endovascular treatment of combined lesions with a review of the relevant literature.

Usefulness of CT Perfusion in the Postoperative Evaluation of Ruptured Aneurysm / 대한뇌혈관외과학회지

OBJECTIVE: Our goal was to evaluate the usefulness of CT perfusion (CTP) in early detection of the post operative cerebral ischemia, alteration of treatment modality and patient prognosis in cerebral aneurysm patients. METHODS: 24 patients who underwent either surgical operation or endovascular coiling for ruptured aneurysms were selected. All patients undertook an angiogram, conventional CT, and CTP scan immediately following surgical operation or endovascular coiling. All patients performed a CT 2 weeks after treatment to evaluate possible development of a cerebral infarction. Postoperative CT results of patients with abnormal postoperative CTP scan findings were compared, and these results were compared with the CT results and clinical symptoms of patients who developed infarction or not. RESULTS: Of the 24 patients evaluated, 11 patients showed abnormal findings on CTP. 9 patients were diagnosed with cerebral infarction through a CT scan done 2 weeks after treatment; all exhibited abnormal CTP results immediately after treatment. Abnormal CTP findings were divided into two groups; patients with abnormal CBF and MTT maps, but with normal CBV maps, and patients with abnormal CBF, CBV and MTT maps. A correlation was seen between abnormality on CBV maps and cerebral infarction. Patients with abnormal CTP findings also exhibited poorer prognostic value. CONCLUSION: Postoperative CTP in ruptured aneurysm patients is a very useful and objective tool in evaluating abnormal cerebral hemodynamics. The CBV map of CTP is the most precisely predictable value of postoperative patient's status and alteration of treatement modality.

Rosai-Dorfman Disease in Posterior Fossa

Rosai-Dorfman Disease(RDD) is an idiopathic histiocytic proliferation affecting lymph nodes. Although extranodal involvement has been reported in the skin, orbit, upper respiratory tract, or testes, the isolated intracranial involvement without associated lymphadenopathy is extremely rare. We report our experience with 1 case of an isolated intracranial RDD without associated lymphadenopathy and any other organ involvement. A 61-year-old male presented with an isolated well-circumscribed brain mass in the posterior fossa, preoperatively thought to be a meningioma. But histology and immunohistochemistry confirmed that the lesion was RDD.

Transcranial Doppler and Cerebrospinal Fluid Flow Study in Normal Pressure Hydrocephalus

OBJECTIVE: The authors analyze prospectively the result of transcranial doppler(TCD) in normal pressure hydrocephalus and compared its cerebral blood flow parameters to radionuclide cerebrospinal fluid(CSF) flow study, postoperative brain computed tomography(CT) findings and clinical outcome, and studied the relationship betweeen cerebral hemodynamics and clinical performance. METHODS: Twenty five patients with hydrocephalus undertook pre- and post-operative TCD but only preoperative CSF flow study was performed. Mean flow velocity(Vm), pulsatility index(PI) and resistance index(RI) were assessed through TCD and changes in ventricle size and cortical gyral atrophy were checked through brain CT. RESULTS: Postoperative hydrocephalus showed an increase in Vm(ACA P=0.037, MCA P=0.034), decrease in PI(ACA P=0.019, MCA P=0.017) and decrease in RI (ACA P=0.017, MCA P=0.021) compared to preoperative TCD parameters in the postoperative improvement group. In the postoperative improvement group, postoperative TCD parameters correlated with CSF flow study grade (Vm: R2=-0.75, PI: R2=0.86, RI: R2=0.78) and ventriculocranial ratio change correlated with PI change (R2=0.73). The convexity gyral atrophy and initial TCD parameters showed close relationship to outcome. CONCLUSION: PI and RI can be used as an indicator of post operative prognosis, and with the addition of CSF flow study values, can also be used as a tool to predict pre-op and post-op patient status and successful shunt surgery.

Perfusion Computed Tomography and Trancranial Doppler in Aneurysmal Subarachnoid Hemorrhage / 대한뇌혈관외과학회지

OBJECT: This study is designed to estimate the clinical usefulness of perfusion computed tomography (perfusion CT) as an easily accessible tool to evaluate cerebral blood flow (CBF) in patients with aneurysmal subarachnoid hemorrhage. METHOD: Twenty patients with aneurysmal spontaneous subarachnoid hemorrhage who underwent either aneurysmal neck clipping or interventional coil embolization and who also had taken transcranial doppler study and perfusion CT were included as study group. And as a control group, fifteen patients without neurologic deficit were studied with the same devices. We compared the cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) from obtained perfusion CT with the results of transcranial doppler and clinical course. RESULTS: CBF parameters of perfusion CT in control group showed close accordance with those values of reported xenon CT and positron emission tomography data. In doppler study, the blood flow velocity was higher in cases with vasospasm than without it (p=0.027). There showed significant relationship between vasospasm and perfusion CT parameters, as decrease in CBF (p=0.061) and increase in MTT (p=0.013). Perfusion CT parameters were closely correlated with TCD parameters in clinical vasospasm as reverse correlation in CBF (R2=0.45) and positive in MTT (R2=0.58). CONCLUSION: The cerebral blood flow parameters of Perfusion CT showed reliable and accurate values in control group. The perfusion CT and TCD can be used as easily accessible non-invasive tools to evaluate cerebral blood flow parameters in clinical settings of patients with aneurysmal subarachnoid hemorrhage.

First-Pass Perfusion Computed Tomography and Transcranial Doppler in Hydrocephalus / 대한뇌혈관외과학회지

OBJECTIVES: The aim of this study are clinical application of perfusion computed tomography (perfusion CT) in hydrocephalus and comparison its cerebral blood flow parameters with transcranial doppler (TCD) and clinical outcome. METHOD: 25 patients with hydrocephalus took pre- and postoperative perfusion CT and TCD. 15 patients without neurologic deficit were also examined with same protocol as a control. Blood flow parameters of perfusion CT, such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were analyzed according to clinical status and postoperative outcome. So did the TCD parameters, mean flow velocity (mFv) and pulsatility index (PI) with regard to clinical outcome. RESULTS: Perfusion CT parameters of the hydrocephalus showed decrease in CBF (gray matter P=0.035, periventricular region P=0.042) and increase in MTT (gray matter P=0.039, periventricular region P=0.045) compared to control. In postoperative improvement group, there noted reversal of perfusion parameters close to those of the control. TCD parameters showed increase in mFv (P=0.047), and decrease in PI (P=0.042) in cases with improvement. CONCLUSION: Perfusion brain CT and TCD can used as clinically useful tools to predict the postoperative outcome on hydrocephalus.

Prognostic Factors in Spontaneous Primary Intraventricular Hemorrhage

OBJECTIVE: TA retrospective study is performed on 28 patients with primary intraventricular hemorrhage(PIVH) to examine the outcome and prognostic factors associated with this disorder. METHODS: Clinical data collected between 1998 and 2002 was used in the present study. The outcomes of these patients were compared by age, etiology, initial Glasgow Coma Score(GCS), Graeb's score, ventriculocranial ratio(VCR), hemorrhagic dilation of the third ventricle, and hemorrhagic dilation of the fourth ventricle. The Glasgow Outcome Scale(GOS) at discharge was used for the comparison of outcomes. RESULTS: The mean age of these patients was 48.4+/-17.4 years. The underlying causes of PIVH were hypertension(53.6%), moyamoya disease(17.9%), arteriovenous malformation(10.7%), cerebral aneurysm(7.1%), and unknown(10.7%). The age and etiology were not correlated with outcome. Patients with a GCS of 13-15 showed a good outcome in 90.5%(p or =0.23) showed a poor outcome in 64.3%(p<0.05). Patients with a Graeb's score of 9-12 showed a poor outcome in 87.5%(p<0.05). Those with hemorrhagic dilatation of the third ventricle showed a poor outcome in 80.0%, and those with hemorrhagic dilatation of the fourth ventricle showed a poor outcome in 85.7%(p<0.05). The overall mortality rate was 17.9%. CONCLUSION: Low initial GCS, high Graeb's score, high VCR, and hemorrhagic dilatation of the third ventricle or the fourth ventricle are correlated with poor outcome in PIVH.

Complications of Endovascular Detachable Coil Treatment in Cerebral Aneurysms

OBJECTIVE: The purpose of this study is to evaluate complications in 70 patients who had underwent endovascular treatment to occlude cerebral aneurysms. METHODS: From May 1999 to December 2002, we treated 70 patients by endovascular treatment or by combination of endovascular treatment and surgery. Complications have been developed in fifteen patients. Twelve patients had anterior circulation aneurysms: 4 posterior commmuncating artery ; 2 anterior communicating artery ; 2 paraclinoid artery ; 2 anterior choroidal artery ; 1 distal internal carotid artery ; 1 middle cerebral artery ; 1 pericallosal artery and three patients had posterior circulation aneurysms: 3 basilar artery tip. RESULTS: The complications related to the coil embolization were the thromboembolic event in 9 cases, rupture of the aneurysm in 3 cases, coil prolapse in 3 cases and coil migration in 1 case. CONCLUSION: The coil embolization can be a alternative good modality in the treatment of cerebral aneurysms. But careful attention should be required to reduce the various complications of procedures and to improve the prognosis of aneurysmal treatment. Effort to overcome the technical problem and to develop more comfortable device are needed for the better results of endovascular treatment.

Barbiturate Coma Therapy in Severe and Refractory Vasospasm Following Subarachnoid Hemorrhage

OBJECTIVE: This study is designed to evaluate the therapeutic effects and prognostic factors for barbituate coma therapy(BCT)in severe and refractory vasospasm following subarachnoid hemorrhage. METHODS: Barbiturate coma therapy was used in 18 patients with severe and refractory vasospasm in spite of "3-H therapy" and intra-arterial papaverine infusion. The authors analyzed the clinical parameters including Glasgow Coma Scale(GCS), electroenceplographic finding, and brain computerized tomography(CT) scan findings in relation to outcome at discharge. RESULTS: Among 18 patients, burst suppression pattern could be obtained in 17. In cases with good outcome, the duration elapsed from coma to drowsiness after BCT was 14.09+/-5.82 days and GCS score at this time was significant in the prediction of final outcome(p<0.05). Patients with ideal burst suppression pattern attainable more than 24 to 48 hours showed good outcome in 81.8%(p<0.05). The group that showed focal low density in the brain CT scan taken before BCT fared better prognosis compared with that of multifocal or diffuse low density(p<0.05), and patients with resolution of perimesencephalic cistern effacement on follow-up brain CT scan taken 48 hours after BCT showed better prognosis(p<0.05). Overall, 72.2% showed improvement of GCS score by 2 or more, and good outcome was noted in 50%. CONCLUSION: The barbiturate coma therapy seems to have a beneficial therapeutic effect on severe and refractory vasospasm and can be considered as a useful therapeutic modality.

Growing Basilar Artery Bifurcation Area Aneurysm: Case Report

The authors present the case of basilar artery bifurcation area aneurysm showing the growth of sac. A 46-year-old man was admitted for evaluation of fluctuating dysarthria. He had a history of lacunar infarction 3 years ago. The cerebral angiogram, taken at that time, showed a small aneurysm on basilar artery bifurcation area. Surgical intervention was not performed because of its small size. Brain MRI, taken for evaluation of dysarthria, showed large signal void at the basilar artery bifurcation area and following cerebral angiogram revealed the growth of previous aneurysm in its size. This observation suggests that careful follow-up examination should be performed for incidental small sized aneurysm.

Clinical Analysis of the Delayed Post-Traumatic Epidural Hematoma after Hematoma Evacuation

OBJECTIVE: The authors analyze the incidence, etiological and prognostic factors between contralateral and ipsilateral delayed epidural hematoma after evacuation of initial hematoma and to formulate recommendations for early detection of evolving hematoma and improvement of outcome. METHODS: Between July 1997 and December 1999, 417 patients underwent craniotomy at department of neurosurgery to evacuate an acute posttraumatic intracranial hematoma. Analysis of these clinical and neuroradiologic data showed that we underwent a second operation on 24 patient(5.8%) for removal of delayed epidural hematoma. In 10(2.4%) of these patients the second operation was undertaken to evacuate a new hematoma that had developed at a contralateral side from the initial hematoma. In 14 patients(3.4%), the second operation was to remove a epidural hematoma at the same site as the first craniotomy. RESULTS: 24 patients were divided into two groups. In Group A, 10 patients who developed contralateral delayed epidural hematoma were 31.5 years(11-61) of age and had skull fracture at the site of delayed epidual hematoma formation. Two of these patients revealed severe brain swelling during the evacuation of acute subdural hematoma. Eight of them were diagnosed within 24 hours after craniotomy through immediately postoperative computed tomography scan. In Group B, 14 patients who developed ipsilateral epidural hematoma were 56.1 years(27-75) of age. Six of them had hemorrhagic tendency related to past medical history. Eleven of these patients were associated with thrombocytopenia and consumptive coagulopathy when required second operation. Twelve patients were diagnosed within 48-72 hours after craniotomy due to clinical deterioration or failure to improve. There was no significant difference in outcome between two groups. CONCLUSION: The authors sought differential factors between contralateral and ipsilateral delayed epidural hematoma. Delayed epidural hematoma after craniotomy may need an urgent operation or lead to serious complication or disability. Postoperative computed tomography scan, intracranial pressure monitoring and repeat computed tomography scan within 72 hours of injury are strongly recommended in these cases, especially after decompression of cranial cavity.