Flow arrest during carotid artery stenting with a distal embolic protection device: A single-center experience and clinical implications

Objective@#We aimed to investigate the incidence of flow arrest during carotid artery stenting (CAS) with filter-type embolic protection device (EPD), identify any predisposing factors for those situations, and contemplate intraprocedural precautionary steps. @*Methods@#CAS was performed in 128 patients with 132 arteries using filter-type EPD. The characteristics of treated patients and arteries were compared between groups with and without flow arrest. @*Results@#The incidence of flow arrest during CAS with filter-type EPD was 17.4%. In flow arrest group, cases of vulnerable plaques (p=0.02) and symptomatic lesions (p=0.01) were significantly more common, and there were more cases of debris captured by EPD in a planar pattern (p<0.01). Vulnerable plaques were significantly more common in the procedures showing a planar pattern than in the cases with other patterns (p<0.01). Flow arrest group showed a significantly higher rate of ischemic complications (p<0.05), although there were no significant periprocedural neurological changes. The planar pattern of captured debris in filter-type EPD was the only significant risk factor for flow arrest (adjusted odds ratio 88.44, 95% confidence interval 15.21-514.45, p<0.05). @*Conclusions@#Flow arrest during CAS with filter-type EPD is not uncommon and associated with increased ischemic complications. Symptomatic stenoses and vulnerable plaque are related to this event. The planar pattern of captured debris on the EPD was the only significant risk factor for the flow arrest. Clinicians must pay attention to the occurrence of flow arrest and react quickly when performing CAS.

Numerical Model for Cerebrovascular Hemodynamics with Indocyanine Green Fluorescence Videoangiography

Objective@#: The use of indocyanine green videoangiography (ICG-VA) to assess blood flow in the brain during cerebrovascular surgery has been increasing. Clinical studies on ICG-VA have predominantly focused on qualitative analysis. However, quantitative analysis numerical modelling for time profiling enables a more accurate evaluation of blood flow kinetics. In this study, we established a multiple exponential modified Gaussian (multi-EMG) model for quantitative ICG-VA to understand accurately the status of cerebral hemodynamics. @*Methods@#: We obtained clinical data of cerebral blood flow acquired the quantitative analysis ICG-VA during cerebrovascular surgery. Varied asymmetric peak functions were compared to find the most matching function form with clinical data by using a nonlinear regression algorithm. To verify the result of the nonlinear regression, the mode function was applied to various types of data. @*Results@#: The proposed multi-EMG model is well fitted to the clinical data. Because the primary parameters—growth and decay rates, and peak centres and heights—of the model are characteristics of model function, they provide accurate reference values for assessing cerebral hemodynamics in various conditions. In addition, the primary parameters can be estimated on the curves with partially missed data. The accuracy of the model estimation was verified by a repeated curve fitting method using manipulation of missing data. @*Conclusion@#: The multi-EMG model can possibly serve as a universal model for cerebral hemodynamics in a comparison with other asymmetric peak functions. According to the results, the model can be helpful for clinical research assessment of cerebrovascular hemodynamics in a clinical setting.

Location of Ulnar Nerve Branches to the Flexor Carpi Ulnaris during Surgery for Cubital Tunnel Syndrome

Objective@#: Cubital tunnel syndrome, the most common ulnar nerve entrapment neuropathy, is usually managed by simple decompression or anterior transposition. One of the concerns in transposition is damage to the nerve branches around the elbow. In this study, the location of ulnar nerve branches to the flexor carpi ulnaris (FCU) was assessed during operations for cubital tunnel syndrome to provide information to reduce operation-related complications. @*Methods@#: A personal series (HJY) of cases operated for cubital tunnel syndrome was reviewed. Cases managed by transposition and location of branches to the FCU were selected for analysis. The function of the branches was confirmed by intraoperative nerve stimulation and the location of the branches was assessed by the distance from the center of medial epicondyle. @*Results@#: There was a total of 61 cases of cubital tunnel syndrome, among which 31 were treated by transposition. Twenty-one cases with information on the location of branches were analyzed. The average number of ulnar nerve branches around the elbow was 1.8 (0 to 3), only one case showed no branches. Most of the cases had one branch to the medial head, and one other to the lateral head of the FCU. There were two cases having branches without FCU responses (one branch in one case, three branches in another). The location of the branches to the medial head was 16.3±8.6 mm distal to the medial epicondyle (16 branches; range, 0 to 35 mm), to the lateral head was 19.5±9.5 mm distal to the medial epicondyle (19 branches; range, -5 to 30 mm). Branches without FCU responses were found from 20 mm proximal to the medial condyle to 15 mm distal to the medial epicondyle (five branches). Most of the branches to the medial head were 15 to 20 mm (50% of cases), and most to the lateral head were 15 to 25 mm (58% of cases). There were no cases of discernable weakness of the FCU after operation. @*Conclusion@#: In most cases of cubital tunnel syndrome, there are ulnar nerve branches around the elbow. Although there might be some cases with branches without FCU responses, most branches are to the FCU, and are to be saved. The operator should be watchful for branches about 15 to 25 mm distal to the medial epicondyle, where most branches come out.

Delayed Trochlear Nerve Palsy Following Traumatic Subarachnoid Hemorrhage: Usefulness of High-Resolution Three Dimensional Magnetic Resonance Imaging and Unusual Course of the Nerve / 대한신경손상학회지

Cranial nerve palsies are relatively common after trauma, but trochlear nerve palsy is relatively uncommon. Although traumatic trochlear nerve palsy is easy to diagnose clinically because of extraocular movement disturbances, radiologic evaluations of this condition are difficult to perform because of the nerve's small size. Here, we report the case of a patient with delayed traumatic trochlear nerve palsy associated with a traumatic subarachnoid hemorrhage (SAH) and the related radiological findings, as obtained with high-resolution three-dimensional (3D) magnetic resonance imaging (MRI). A 63-year-old woman was brought to the emergency room after a minor head trauma. Neurologic examinations did not reveal any focal neurologic deficits. Brain computed tomography showed a traumatic SAH at the left ambient cistern. The patient complained of vertical diplopia at 3 days post-trauma. Ophthalmologic evaluations revealed trochlear nerve palsy on the left side. High-resolution 3D MRI, performed 20 days post-trauma, revealed continuity of the trochlear nerve and its abutted course by the posterior cerebral artery branch at the brain stem. Chemical irritation due to the SAH and the abutting nerve course were considered causative factors. The trochlear nerve palsy completely resolved during follow-up. This case shows the usefulness of high-resolution 3D MRI for evaluating trochlear nerve palsy.

Metal Artifact Reduction for Orthopedic Implants: Brain CT Angiography in Patients with Intracranial Metallic Implants

BACKGROUND: The purpose of this study was to qualitatively and quantitatively evaluate the effects of a metal artifact reduction for orthopedic implants (O-MAR) for brain computed tomographic angiography (CTA) in patients with aneurysm clips and coils. METHODS: The study included 36 consecutive patients with 47 intracranial metallic implants (42 aneurysm clips, 5 coils) who underwent brain CTA. The computed tomographic images with and without the O-MAR were independently reviewed both quantitatively and qualitatively by two reviewers. For quantitative analysis, image noises near the metallic implants of non-O-MAR and O-MAR images were compared. For qualitative analysis, image quality improvement and the presence of new streak artifacts were assessed. RESULTS: Image noise was significantly reduced near metallic implants (P < 0.01). Improvement of implant-induced streak artifacts was observed in eight objects (17.0%). However, streak artifacts were aggravated in 11 objects (23.4%), and adjacent vessel depiction was worsened in eight objects (17.0%). In addition, new O-MAR-related streak artifacts were observed in 32 objects (68.1%). New streak artifacts were more prevalent in cases with overlapping metallic implants on the same axial plane than in those without (P = 0.018). Qualitative assessment revealed that the overall image quality was not significantly improved in O-MAR images. CONCLUSION: In conclusion, the use of the O-MAR in patients with metallic implants significantly reduces image noise. However, the degree of the streak artifacts and surrounding vessel depiction were not significantly improved on O-MAR images.

Keyhole Approach and Neuroendoscopy for Cerebral Aneurysms

Treating diseases in the field of neurosurgery has progressed concomitantly with technical advances. Here, as a surgical armamentarium for the treatment of cerebral aneurysms, the history and present status of the keyhole approach and the use of neuroendoscopy are reviewed, including our clinical data. The major significance of keyhole approach is to expose an essential space toward a target, and to minimize brain exposure and retraction. Among several kinds of keyhole approaches, representative keyhole approaches for anterior circulation aneurysms include superciliary and lateral supraorbital, frontolateral, mini-pterional and mini-interhemispheric approaches. Because only a fixed and limited approach angle toward a target is permitted via the keyhole, however, specialized surgical devices and preoperative planning are very important. Neuroendoscopy has helped to widen the indications of keyhole approaches because it can supply illumination and visualization of structures beyond the straight line of microscopic view. In addition, endoscopic indocyanine green fluorescence angiography is useful to detect and correct any compromise of the perforators and parent arteries, and incomplete clipping. The authors think that keyhole approach and neuroendoscopy are just an intermediate step and robotic neurosurgery would be realized in the near future.

Isolated Cortical Vein Thrombosis with Long Cord Sign

Isolated cortical vein thrombosis (ICVT) is a rare disease, accounting for less than 1% of strokes. A 46-year-old woman presented with progressive left side weakness. Magnetic resonance (MR) imaging with T2*-gradient echo (T2*-GE) sequence showed long cord sign at the right frontal cortex. The patient was treated with low molecular weight heparin, followed by oral warfarin for 6 months. The 3-month follow-up MR imaging showed recanalization of the previously thrombosed cortical vein. She was completely recovered without neurological deficits after 6 months. This provides that MR imaging with T2*-GE sequence can help to diagnosis the ICVT and outcomes of the ICVT are generally favorable.

Usefulness of Fracture Risk Assessment Tool Using Lumbar Bone Mineral Density in Prediction of Osteoporotic Vertebral Fracture

OBJECTIVE: To investigate the value of lumbar bone mineral density (BMD) in fracture risk assessment (FRAX) tool. METHODS: One hundred and ten patients aged over 60 years were enrolled and divided into 2 groups as non-osteoporotic vertebral fracture (OVF) and OVF groups. The 10-year-risk of major osteoporotic vertebral fracture of each group was calculated by FRAX tool with femoral and lumbar spine BMDs to compare the usefulness of lumbar spine BMD in prediction of OVF. The blood level of osteocalcin and C-terminal telopeptide (CTX) as markers of activities of osteoblast and osteoclast, respectively were analyzed using the institutional database. RESULTS: In the OVF group, the ratio of patients with previous fracture history or use of glucocorticoid was higher than those in non-OVF group (p=0.000 and 0.030, respectively). The levels of T-score of femur neck and lumbar spine in OVF group were significantly lower than those in non-OVF group (p=0.001 and 0.000, respectively). The risk of OVF in FRAX using femur BMD in non-OVF and OVF groups was 6.7+/-6.13 and 11.4+/-10.06, respectively (p=0.007). The risk of using lumbar BMD in the 2 groups was 6.9+/-8.91 and 15.1+/-15.08, respectively (p=0.002). The areas under the receiver operator characteristic curve in the FRAX risk with lumbar and femur neck BMD were 0.726 and 0.684, respectively. The comparison of osteocalcin and CTX was not significant (p=0.162 and 0.369, respectively). CONCLUSION: In our study, the 10-year risk of major osteoporotic fracture in the OVF group of our study was lower than the recommended threshold of intervention for osteoporosis. Hence, a lower threshold for the treatment of osteoporosis may be set for the Korean population to prevent OVF. In the prediction of symptomatic OVF, FRAX tool using lumbar spine BMD may be more useful than that using femur neck BMD.

Post-Carotid Endarterectomy Cerebral Hyperperfusion Syndrome : Is It Preventable by Strict Blood Pressure Control?

OBJECTIVE: Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid endarterectomy (CEA). However, the prevalence of CHS has decreased as techniques have improved. This study evaluates the role of strict blood pressure (BP) control for the prevention of CHS. METHODS: All 18 patients who received CEA from February 2009 through November 2012 were retrospectively reviewed. All patients were routinely managed in an intensive care unit by a same protocol. The cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow (rCBF) study by perfusion computed tomography (pCT) and mean velocity by transcranial doppler (TCD). BP was strictly controlled (100% increase in the rCBF by pCT or in the mean velocity by TCD compared with preoperative values) or CHS was detected, BP was maintained below 120/80 mm Hg. RESULTS: TCD and pCT data on the patients were analyzed. Ipsilateral rCBF was significantly increased after CEA in the pCT (p=0.049). Post-CEA hyperperfusion was observed in 3 patients (18.7%) in the pCT and 2 patients (12.5%) in the TCD study. No patients developed clinical CHS for one month after CEA. Furthermore, no patients developed additional neurological deficits related to postoperative cerebrovascular complications. CONCLUSION: Intensive care with strict BP control (<140/90 mm Hg) achieved a low prevalence of post-CEA hyperperfusion and prevented CHS. This study suggests that intensive care with strict BP control can prevent the prevalence of post-CEA CHS.

Slowly Recovering Isolated Bilateral Abducens Nerve Palsy after Embolization of Ruptured Anterior Communicating Artery Aneurysm

Bilateral abducens nerve palsy related to ruptured aneurysm of the anterior communicating artery (ACoA) has only been reported in four patients. Three cases were treated by surgical clipping. No report has described the clinical course of the isolated bilateral abducens nerve palsy following ruptured ACoA aneurysm obliterated with coil. A 32-year-old man was transferred to our institution after three days of diplopia, dizziness and headache after the onset of a 5-minute generalized tonic-clonic seizure. Computed tomographic angiography revealed an aneurysm of the ACoA. Magnetic resonance imaging showed focal intraventricular hemorrhage without brain stem abnormalities including infarction or space-occupying lesion. Endovascular coil embolization was conducted to obliterate an aneurysmal sac followed by lumbar cerebrospinal fluid (CSF) drainage. Bilateral paresis of abducens nerve completely recovered 9 weeks after ictus. In conclusion, isolated bilateral abducens nerve palsy associated with ruptured ACoA aneurysm may be resolved successfully by coil embolization and lumbar CSF drainage without directly relieving cerebrospinal fluid pressure by opening Lillequist's membrane and prepontine cistern.

Large Spinal Meningioma with Hemorrhage after Selective Root Block in the Thoraco-Lumbar Spine

Spinal meningioma accounts for 25% of all spinal cord tumors and occurs mostly in the thoracic region. Spontaneous intraspinal bleeding associated with spinal meningioma has rarely been reported. Most cases of hemorrhage associated with meningiomas are extratumoral and subarachnoid, whereas subdural and intratumoral hemorrhage cases have been reported to occur rarely. We experienced a case of a 58-year-old woman with thoracolumbar spinal meningioma accompanied by intraspinal subdural hematoma. She presented with progressively worsened back pain and newly developed weakness in the right lower extremity after a selective nerve root block in the lumbar spine. She underwent the operation and progressively showed neurological recovery during the postoperative course. We report a thoracolumbarspinal meningioma with subdural and intratumoral hemorrhage after a spinal procedure that caused a sudden neurological deterioration.

Mobile Computed Tomography : Three Year Clinical Experience in Korea

OBJECTIVE: Obtaining real-time image is essential for neurosurgeons to minimize invasion of normal brain tissue and to prompt diagnosis of intracranial event. The aim of this study was to report our three-year experience with a mobile computed tomography (mCT) for intraoperative and bedside scanning. METHODS: A total of 357 mCT (297 patients) scans from January 2009 to December 2011 in single institution were reviewed. After excluding post-operative routine follow-up, 202 mCT were included for analysis. Their medical records such as diagnosis, clinical application, impact on decision making, times, image quality and radiologic findings were assessed. RESULTS: Two-hundred-two mCT scans were performed in the operation room (n=192, 95%) or intensive care unit (ICU) (n=10, 5%). Regarding intraoperative images, extent of resection of tumor (n=55, 27.2%), degree of hematoma removal (n=42, 20.8%), confirmation of catheter placement (n=91, 45.0%) and monitoring unexpected complications (n=4, 2.0%) were evaluated. A total of 14 additional procedures were introduced after confirmation of residual tumor (n=7, 50%), hematoma (n=2, 14.3%), malpositioned catheter (n=3, 21.4%) and newly developed intracranial events (n=2, 14.3%). Every image was obtained within 15 minutes and image quality was sufficient for interpretation. CONCLUSION: mCT is feasible for prompt intraoperative and ICU monitoring with enhanced diagnostic certainty, safety and efficiency.

The Impact of Menopause on Bone Fusion after the Single-Level Anterior Cervical Discectomy and Fusion

OBJECTIVE: To evaluate the successful fusion rate in postmenopausal women with single-level anterior cervical discectomy and successful fusion (ACDF) and identify the significant factors related to bone successful fusion in pre- and postmenopausal women. METHODS: From July 2004 to December 2010, 108 consecutive patients who underwent single-level ACDF were prospectively selected as candidates. Among these, the charts and radiological data of 39 women were reviewed retrospectively. These 39 women were divided into two groups : a premenopausal group (n=11) and a postmenopausal group (n=28). To evaluate the significant factors affecting the successful fusion rate, the following were analyzed : the presence of successful fusion, successful fusion type, age, operated level, bone mineral density, graft materials, stand-alone cage or plating with autologous iliac bone, subsidence, adjacent segment degeneration, smoking, diabetes mellitus, and renal disease. RESULTS: The successful fusion rates of the pre- and postmenopausal groups were 90.9% and 89.2%, respectively. There was no significant difference in the successful fusion rate or successful fusion type between the two groups. In the postmenopausal group, three patients (10.8%) had successful fusion failure. In the postmenopausal group, age and subsidence significantly affected the successful fusion rate (p=0.016 and 0.011, respectively), and the incidence of subsidence in patients with a cage was higher than that in patients with a plate (p=0.030). CONCLUSION: Menopausal status did not significantly affect bone successful fusion in patients with single-level ACDF. However, in older women with single-level ACDF, the combination of use of a cage and subsidence may unfavorably affect successful fusion.

Quantitative Evaluation of Median Nerve Motor Function in Carpal Tunnel Syndrome Using Load Cell : Correlation with Clinical, Electrodiagnostic, and Ultrasonographic Findings

OBJECTIVE: Major complaints of carpal tunnel syndrome (CTS) are sensory components. However, motor deficit also impedes functional status of hand. Contrary to evaluation of sensory function, the objective, quantitative evaluation of median nerve motor function is not easy. The motor function of median was evaluated quantitatively using load cell and its correlation with findings of electrodiagnostic study (EDS) was evaluated. METHODS: Objective motor function of median nerve was evaluated by load cell and personal computer-based measurement system. All of the measurement was done in patients diagnosed as having idiopathic CTS by clinical features and EDS findings. The strength of thumb abduction and index finger flexion was measured in each hand three times, and the average value was used to calculate thumb index ratio (TIR). The correlation of TIR with clinical, EDS, and ultrasonographic findings were evaluated. RESULTS: The TIR was evaluated in 67 patients (119 hands). There were 14 males and 53 females, mean age were 57.6 years (range 28 to 81). The higher preoperative nerve conductive studies grade of the patients, the lower TIR was observed [p<0.001, analysis of variance (ANOVA)]. TIR of cases with thenar atrophy were significantly lower than those without (p<0.001, t-test). TIR were significantly lower in patients with severe median nerve swelling in ultrasonography (p=0.042, ANOVA). CONCLUSION: Measurements of median nerve motor function using load cell is a valuable evaluation tool in CTS. It might be helpful in detecting subclinical motor dysfunction before muscle atrophy develops.

Quantitative Analysis of Intraoperative Indocyanine Green Video Angiography in Aneurysm Surgery

OBJECTIVE: Indocyanine green (ICG) videoangiography (VA) is being used in assessment of blood flow during cerebrovascular surgery. However, data collected during ICG angiography are usually interpreted qualitatively. In this study, quantitative analysis of ICG angiogram was attempted. MATERIALS AND METHODS: ICG VA, performed during aneurysm surgery was analyzed retrospectively. The angiogram was captured serially in regular time interval. The stacked images were then fed into an image analysis program, ImageJ. The selected areas of interest were as follows: parent and branch vessels, and dome of aneurysm. Changes of signals of measurement points were plotted. The time to peak, washout time, and the peak intensity between areas were compared. RESULTS: Among the 16 cases enrolled in this study, five cases were anterior communicating artery aneurysms, and 11 cases were middle cerebral artery bifurcation aneurysms. There was no signal intensity of aneurysm dome in our series. No difference in time to peak or maximum signal intensity was observed between vessels in each case. The average time to peak was 9.0 and washout time was 31.3 seconds. No significant difference in time profile was observed between anterior communicating artery aneurysms and middle cerebral artery bifurcation aneurysms. CONCLUSION: Findings of this study demonstrate that quantitative analysis is possible using a personal computer and common video capture and analysis software. It can be a good adjunctive to evaluation of vascular status during aneurysm surgery. It displays time profiles of multiple points of interest over time, and is helpful in objective evaluation of changes of blood flow over time. It might be helpful in various fields of cerebrovascular surgery.

Dissecting Aneurysm of Vertebral Artery Manifestating as Contralateral Abducens Nerve Palsy

Isolated abducens nerve paresis related to ruptured vertebral artery (VA) aneurysm is rare. It usually occurs bilaterally or ipsilaterally to the pathologic lesions. We report the case of a contralateral sixth nerve palsy following ruptured dissecting VA aneurysm. A 38-year-old man was admitted for the evaluation of a 6-day history of headache. Abnormalities were not seen on initial computed tomography (CT). On admission, the patient was alert and no signs reflecting neurologic deficits were noted. Time of flight magnetic resonance angiography revealed a fusiform dilatation of the right VA involving origin of the posterior inferior cerebellar artery. The patient suddenly suffered from severe headache with diplopia the day before the scheduled cerebral angiography. Neurologic examination disclosed nuchal rigidity and isolated left abducens nerve palsy. Emergent CT scan showed high density in the basal and prepontine cistern compatible with ruptured aneurismal hemorrhage. Right vertebral angiography illustrated a right VA dissecting aneurysm with prominent displaced vertebrobasilar artery to inferiorly on left side. Double-stent placement was conducted for the treatment of ruptured dissecting VA aneurysm. No diffusion restriction signals were observed in follow-up magnetic resonance imaging of the brain stem. Eleven weeks later, full recovery of left sixth nerve palsy was documented photographically. In conclusion, isolated contralateral abducens nerve palsy associated with ruptured VA aneurysm may develop due to direct nerve compression by displaced verterobasilar artery triggered by primary thick clot in the prepontine cistern.

Analysis of Complications Following Decompressive Craniectomy for Traumatic Brain Injury

OBJECTIVE: Adequate management of increased intracranial pressure (ICP) is critical in patients with traumatic brain injury (TBI), and decompressive craniectomy is widely used to treat refractory increased ICP. The authors reviewed and analyzed complications following decompressive craniectomy for the management of TBI. METHODS: A total of 89 consecutive patients who underwent decompressive craniectomy for TBI between February 2004 and February 2009 were reviewed retrospectively. Incidence rates of complications secondary to decompressive craniectomy were determined, and analyses were performed to identify clinical factors associated with the development of complications and the poor outcome. RESULTS: Complications secondary to decompressive craniectomy occurred in 48 of the 89 (53.9%) patients. Furthermore, these complications occurred in a sequential fashion at specific times after surgical intervention; cerebral contusion expansion (2.2 +/- 1.2 days), newly appearing subdural or epidural hematoma contralateral to the craniectomy defect (1.5 +/- 0.9 days), epilepsy (2.7 +/- 1.5 days), cerebrospinal fluid leakage through the scalp incision (7.0 +/- 4.2 days), and external cerebral herniation (5.5 +/- 3.3 days). Subdural effusion (10.8 +/- 5.2 days) and postoperative infection (9.8 +/- 3.1 days) developed between one and four weeks postoperatively. Trephined and post-traumatic hydrocephalus syndromes developed after one month postoperatively (at 79.5 +/- 23.6 and 49.2 +/- 14.1 days, respectively). CONCLUSION: A poor GCS score ( or = 65 were found to be related to the occurrence of one of the above-mentioned complications. These results should help neurosurgeons anticipate these complications, to adopt management strategies that reduce the risks of complications, and to improve clinical outcomes.

Mobile Computed Tomography : Early Experience in Korea

OBJECTIVE: With improved technology, the values of intraoperative computed tomography (iCT) have been reevaluated. We describe our early clinical experience with a mobile CT (mCT) system for iCT and discuss its clinical applications, advantages and limitations. METHODS: Compared with intraoperative magnetic resonance imaging, this mCT system has no need for major reconstruction of a preexisting operating room for shielding, or for specialized instruments or equipment. Patients are placed on a radiolucent head clamp that fits within the gantry. Because it consists simply of a scanner and a workstation, it can be moved between locations such as an operating room, an intensive care unit (ICU) or an emergency room without difficulty. Furthermore, it can achieve nearly all types of CT scanning procedures such as enhancement, temporal bone imaging, angiography and three-dimensional reconstruction. RESULTS: For intracranial surgery, mCT can be used for intraoperative real-time neuronavigation by interacting with preoperative images. It can also be used for intraoperative confirmation of the extent of resection of intracranial lesions and for immediate checks for preventing intraoperative unexpected accidents. Therefore, the goals of maximal resection or optimal treatment can be achieved without any guesswork. Furthermore, mCT can achieve improved patient care with safety and faster diagnosis for patients in an ICU who might be subjected to a ventilator and/or various monitoring devices. CONCLUSION: Our initial experience demonstrates that mCT with high-quality imaging offers very useful information in various clinical situations.

Intracranial Pial Arteriovenous Fistulas

Intracranial pial arteriovenous fistula (AVF) is a rare cerebrovascular lesion that has only recently been recognized as a distinct pathological entity. A 41-year-old woman (Patient 1) presented with the sudden development of an altered mental state. Brain CT showed an acute subdural hematoma. A red sylvian vein was found intraoperatively. A pial AVF was revealed on postoperative angiography, and surgical disconnection of the AVF was performed. A 10-year-old boy (Patient 2) presented with a 10-day history of paraparesis and urinary incontinence. Brain, spinal MRI and angiography revealed an intracranial pial AVF and a spinal perimedullary AVF. Endovascular embolization was performed for both lesions. The AVFs were completely obliterated in both patients. On follow-up, patient 1 reported having no difficulty in performing activities of daily living. Patient 2 is currently able to walk without assistance and voids into a diaper. Intracranial pial AVF is a rare disease entity that can be treated with surgical disconnection or endovascular embolization. It is important for the appropriate treatment strategy to be selected on the basis of patientspecific and lesion-specific factors in order to achieve good outcomes.

Surgical Results of Intramedullary Spinal Cord Ependymomas in Adults: Retrospective Analysis of 51 Cases

OBJECTIVE: The goal of treatment for spinal cord ependymoma is complete removal without postoperative neurological deficit. The authors analyzed the surgical results and factors influencing the postoperative prognosis. METHODS: Fifty-one cases of primary spinal cord ependymoma, surgically treated between 1979 and 2003, were retrospectively analyzed. The mean follow-up period was 44 months. RESULTS: Gross total removal was achieved in 42 patients and incomplete removal in nine. The proportion of complete surgical removals was influenced by tumor location and histology. Disease progression was observed in five cases (9.8%), the mean progression free interval after surgical removal was 48 months and the 5-year progression free rate was 68%. Disease progression was found in none of the 42 cases who underwent complete removal, and in 5 of 9 cases who hadincomplete removal group (P<0.001). Statistically significant disease-progression factors by multivariate analysis were the surgical extent of removal (P=0.012), preoperative functional status (P=0.032), the presence of intratumoral cysts (P=0.007) and postoperative radiation therapy (P=0.042). Of those patients who underwent incomplete removal, radiation therapy was found to significantly improve the clinical result (P=0.042). CONCLUSION: In the surgical treatment of spinal cord ependymoma, preoperative functional status, the presence of intratumoral cysts, the extent of removal, and postoperative radiation therapy were found to be significant prognostic factors of postoperative outcome.