Gliosarcoma of Cerebello-Pontine Angle: A Case Report and Review of the Literature

Gliosarcoma (GS), known as variant of glioblastoma multiforme, is aggressive and very rare primary central nervous system malignant neoplasm. They are usually located in the supratentorial area with possible direct dural invasion or only reactive dural thickening. However, in this case, GS was located in lateral side of left posterior cranial fossa. A 78-year-old man was admitted to our hospital with 3 month history of continuous dizziness and gait disturbance without past medical history. A gadolinium-enhanced MRI demonstrated 5.6×4.8×3.2 cm sized mass lesion in left posterior cranial fossa, heterogeneously enhanced. The patient underwent left retrosigmoid craniotomy with navigation system. The tumor was combined with 2 components, whitish firm mass and gray colored soft & suckable mass. On pathologic report, the final diagnosis was GS of WHO grade IV. In spite of successful gross total resection of tumor, we were no longer able to treat because of the patient's rejection of adjuvant treatment. The patient survived for nine months without receiving any special treatment from the hospital.

Morphometric Study of the Lumbar Posterior Longitudinal Ligament

OBJECTIVE: Morphometric data for the lumbar posterior longitudinal ligament (PLL) was investigated to identify whether there is a difference in the morphometry of the PLL of the lumbar spine at each level with respect to the pattern of intervertebral disc displacement. METHODS: In 14 formalin-fixed adult cadavers (12 males and 2 females), from L1 to L5, the authors measured the width and height of the PLL and compared them with other landmarks such as the disc and the pedicle. RESULTS: Horizontally, at the upper margin of the disc, the central portion of the superficial PLL covered 17.8–36.9% of the disc width and the fan-like portion of the PLL covered 63.9–76.7% of the disc width. At the level of the median portion of the disc, the PLL covered 69.1–74.5% of the disc width. Vertically, at the level of the medial margin of the pedicle, the fan-like portion of the PLL covered 23.5–29.9% of the disc height. In general, a significant difference in length was not found in the right-left and male-female comparisons. CONCLUSION: This study presents the morphometric data on the pattern of intervertebral disc displacement and helps to improve the knowledge of the surgical anatomy of the lumbar PLL.

Morphometric Study of the Lumbar Posterior Longitudinal Ligament

OBJECTIVE: Morphometric data for the lumbar posterior longitudinal ligament (PLL) was investigated to identify whether there is a difference in the morphometry of the PLL of the lumbar spine at each level with respect to the pattern of intervertebral disc displacement.METHODS: In 14 formalin-fixed adult cadavers (12 males and 2 females), from L1 to L5, the authors measured the width and height of the PLL and compared them with other landmarks such as the disc and the pedicle.RESULTS: Horizontally, at the upper margin of the disc, the central portion of the superficial PLL covered 17.8–36.9% of the disc width and the fan-like portion of the PLL covered 63.9–76.7% of the disc width. At the level of the median portion of the disc, the PLL covered 69.1–74.5% of the disc width. Vertically, at the level of the medial margin of the pedicle, the fan-like portion of the PLL covered 23.5–29.9% of the disc height. In general, a significant difference in length was not found in the right-left and male-female comparisons.CONCLUSION: This study presents the morphometric data on the pattern of intervertebral disc displacement and helps to improve the knowledge of the surgical anatomy of the lumbar PLL.

Efficacy of Balloon-Guiding Catheter for Mechanical Thrombectomy in Patients with Anterior Circulation Ischemic Stroke

OBJECTIVE: To evaluate the efficacy of balloon guiding catheter (BGC) during thrombectomy in anterior circulation ischemic stroke. METHODS: Sixty-two patients with acute anterior circulation ischemic stroke were treated with thrombectomy using a Solitaire stent from 2011 to 2016. Patients were divided into the BGC group (n=24, 39%) and the non-BGC group (n=38, 61%). The number of retrievals, procedure time, thrombolysis in cerebral infarction (TICI) grade, presence of distal emboli, and clinical outcomes at 3 months were evaluated. RESULTS: Successful recanalization was more frequent in BGC than in non-BGC (83% vs. 66%, p=0.13). Distal emboli occurred less in BGC than in non-BGC (23.1% vs. 57.1%, p=0.02). Good clinical outcome was more frequent in BGC than in non-BGC (50% vs. 16%, p=0.03). The multivariate analysis showed that use of BGC was the only independent predictor of good clinical outcome (odds ratio, 5.19: 95% confidence interval, 1.07–25.11). More patients in BGC were successfully recanalized in internal carotid artery (ICA) occlusion with small retrieval numbers (<3) than those in non-BGC (70% vs. 24%, p=0.005). In successfully recanalized ICA occlusion, distal emboli did not occur in BGC, whereas nine patients had distal emboli in non-BGC (0% vs. 75%, p=0.001) and good clinical outcome was superior in BGC than in non-BGC (55.6% vs. 8.3%, p=0.01). CONCLUSION: A BGC significantly reduces the number of retrievals and the occurrence of distal emboli, thereby resulting in better clinical outcomes in patients with anterior circulation ischemic stroke, particularly with ICA occlusion.

Procedure-related Complications during Endovascular Treatment of Intracranial Saccular Aneurysms

OBJECTIVE: We evaluate the rates and outcomes of major procedure-related complications during coiling. MATERIALS AND METHODS: Between 2007 and 2015, 436 intracranial saccular aneurysms were treated. Complications are categorized as three types: intraprocedural aneurysm rupture (IAR), thromboembolism (TE), and post-procedural early rebleeding (PER). And we evaluated the risk factors of procedure related complications by multivariate analysis. RESULTS: Complications occurred in 61 aneurysms (14%). The overall incidence of complications in subarachnoid hemorrhage (SAH) was significantly higher than in unruptured intracranial aneurysm (UIA) (20% vs. 6%). The incidence of IAR and TE were higher in SAH than in UIA (IAR 12% vs. 4%, TE 7% vs. 3%, p 0.05). All 7 patients who had IAR during BAC had good recovery. In multiple logistic regression analysis, female gender, SAH, and intraventricular hemorrhage were associated with procedure related complication (p < 0.05). CONCLUSION: Endovascular coil embolization is a minimally invasive procedure, but incidence of its complication is not low, especially in SAH. BAC can be a good tool to avoid poor outcome from unexpected IAR during coiling. While IA tirofiban injection is a useful therapy in TE during coiling, sometimes we are aware of the risk of the early rebleeding in SAH patients.

The Effectiveness of Gelfoam Technique before Percutaneous Vertebroplasy: Is It Helpful for Prevention of Cement Leakage? A Prospective Randomized Control Study

OBJECTIVE: Preinjection gelfoam embolization during percutaneous vertebroplasty (PVP) has been thought alternative technique to prevent the leakage of bone cement. The goal of this study was to evaluate whether the gelfoam techniques are useful to reduce bone cement leakage. METHODS: Total 100 PVPs of osteoporotic spine compression fractures were performed by 1 spine surgeon who experienced more than 500 PVP cases under prospective control study. Operation was done in T-L junction (T10-L2) fractures with bi-transpedicular approach. Preinjection gelfoam PVP was done in the 50 levels. As control group, PVP without gelfoam was done in the 50 levels. We did not perform preoperative venography. We inserted normal saline-mixed gelfoam to the anterior third of vertebral body via PVP needle, and then 3mL of polymethylmetacrylate (PMMA) was injected. We prospectively evaluated the incidence and leakage pattern of PMMA by postoperative computed tomography. RESULTS: Between gelfoam and control groups, there were 11 leaks (22%) versus 12 leaks (26%). The mean operation time was 7.00 minutes versus 6.30 minutes. In gelfoam group, there were 6 spinal canal leaks, 4 paravertebral venous leaks, and 1 soft tissue leaks. In control group, there were 4 spinal canal leaks, 8 paravertebral venous leaks, and 1 disc space leak. In spite of cement leakage, there was no symptomatic case in both groups. Statistically, gelfoam technique was not related to decrease the incidence of leakage (p=0.64). CONCLUSION: Our prospective study showed that it did not significantly decrease cement leakage when vertebroplasty is performed by experienced spine surgeon.

Device for Catheter Placement of External Ventricular Drain

To introduce a new device for catheter placement of an external ventricular drain (EVD) of cerebrospinal fluid (CSF). This device was composed of three portions, T-shaped main body, rectangular pillar having a central hole to insert a catheter and an arm pointing the tragus. The main body has a role to direct a ventricular catheter toward the right or left inner canthus and has a shallow longitudinal opening to connect the rectangular pillar. The arm pointing the tragus is controlled by back and forth movement and turn of the pillar attached to the main body. Between April 2012 and December 2014, 57 emergency EVDs were performed in 52 patients using this device in the operating room. Catheter tip located in the frontal horn in 52 (91.2%), 3rd ventricle in 2 (3.5%) and in the wall of the frontal horn of the lateral ventricle in 3 EVDs (5.2%). Small hemorrhage along to catheter tract occurred in 1 EVD. CSF was well drained through the all EVD catheters. The accuracy of the catheter position and direction using this device were 91% and 100%, respectively. This device for EVD guides to provide an accurate position of catheter tip safely and easily.

Severe Cerebral Vasospasm in Patients with Hyperthyroidism

Cerebral vasospasm associated with hyperthyroidism has not been reported to cause cerebral infarction. The case reported here is therefore the first of cerebral infarction co-existing with severe vasospasm and hyperthyroidism. A 30-year-old woman was transferred to our hospital in a stuporous state with right hemiparesis. At first, she complained of headache and dizziness. However, she had no neurological deficits or radiological abnormalities. She was diagnosed with hyperthyroidism 2 months ago, but she had discontinued the antithyroid medication herself three days ago. Magnetic resonance imaging and angiography showed cerebral infarction with severe vasospasm. Thus, chemical angioplasty using verapamil was performed two times, and antithyroid medication was administered. Follow-up angiography performed at 6 weeks demonstrated complete recovery of the vasospasm. At the 2-year clinical follow-up, she was alert with mild weakness and cortical blindness. Hyperthyroidism may influence cerebral vascular hemodynamics. Therefore, a sudden increase in the thyroid hormone levels in the clinical setting should be avoided to prevent cerebrovascular accidents. When neurological deterioration is noticed without primary cerebral parenchyma lesions, evaluation of thyroid function may be required before the symptoms occur.

A Morphometric Study of the Obturator Nerve around the Obturator Foramen

OBJECTIVE: Obturator neuropathy is a rare condition. Many neurosurgeons are unfamiliar with the obturator nerve anatomy. The purpose of this study was to define obturator nerve landmarks around the obturator foramen. METHODS: Fourteen cadavers were studied bilaterally to measure the distances from the nerve root to relevant anatomical landmarks near the obturator nerve, including the anterior superior iliac spine (ASIS), the pubic tubercle, the inguinal ligament, the femoral artery, and the adductor longus. RESULTS: The obturator nerve exits the obturator foramen and travels infero-medially between the adductors longus and brevis. The median distances from the obturator nerve exit zone (ONEZ) to the ASIS and pubic tubercle were 114 mm and 30 mm, respectively. The median horizontal and vertical distances between the pubic tubercle and the ONEZ were 17 mm and 27 mm, respectively. The shortest median distance from the ONEZ to the inguinal ligament was 19 mm. The median inguinal ligament lengths from the ASIS and the median pubic tubercle to the shortest point were 103 mm and 24 mm, respectively. The median obturator nerve lengths between the ONEZ and the adductor longus and femoral artery were 41 mm and 28 mm, respectively. CONCLUSION: The obturator nerve exits the foramen 17 mm and 27 mm on the horizontal and sagittal planes, respectively, from the pubic tubercle below the pectineus muscle. The shallowest area is approximately one-fifth medially from the inguinal ligament. This study will help improve the accuracy of obturator nerve surgeries to better establish therapeutic plans and decrease complications.

Endovascular Treatment of Dural Arteriovenous Fistulas: Single Center Experience

OBJECTIVE: Treatment of intracranial dural arteriovenous fistulas (dAVFs) remains a challenge. However, after introduction of Onyx, transarterial approach is the preferred treatment option in many centers. We report our experience of dAVFs embolization with special emphasis on transarterial approach. METHODS: Seventeen embolization procedures were performed in 13 patients with dAVFs between Jan 2009 and Oct 2014. Clinical symptoms, location and type of fistulas, embolization methods, complications, radiological and clinical outcomes were evaluated using charts and PACS images. RESULTS: All 13 patients had symptomatic lesions. The locations of fistulas were transverse-sigmoid sinus in 6, middle fossa dura in 4, cavernous sinus in 2, and superior sagittal sinus in 1 patient. Cognard types were as follows : I in 4, IIa in 2, IIa+IIb in 5, and IV in 2. Embolization procedures were performed > or =2 times in 3 patients. Nine patients were treated with transarterial Onyx embolization alone. One of these required direct surgical puncture of middle meningeal artery. Complete obliteration of fistulas was achieved in 11/13 (85%) patients. There were no complications except for 1 case of Onyx migration in cavernous dAVF. Modified Rankin scale score at post-operative 3 months were 0 in 11, and 3 in 2 patients. CONCLUSION: Transarterial Onyx embolization can be a first line therapeutic option in patients with dAVFs. However, transvenous approach should be tried first in cavernous sinus dAVF because of the risk of intracranial migration of liquid embolic materials. Furthermore, combined surgical endovascular approach can be considered as a useful option in inaccessible route.

Which One Is Better to Reduce the Infection Rate, Early or Late Cranioplasty?

OBJECTIVE: Decompressive craniectomy is an effective therapy to relieve high intracranial pressure after acute brain damage. However, the optimal timing for cranioplasty after decompression is still controversial. Many authors reported that early cranioplasty may contribute to improve the cerebral blood flow and brain metabolism. However, despite all the advantages, there always remains a concern that early cranioplasty may increase the chance of infection. The purpose of this retrospective study is to investigate whether the early cranioplasty increase the infection rate. We also evaluated the risk factors of infection following cranioplasty. METHODS: We retrospectively examined the results of 131 patients who underwent cranioplasty in our institution between January 2008 and June 2015. We divided them into early (≤90 days) and late (>90 days after craniectomy) groups. We examined the risk factors of infection after cranioplasty. We analyzed the infection rate between two groups. RESULTS: There were more male patients (62%) than female (38%). The mean age was 49 years. Infection occurred in 17 patients (13%) after cranioplasty. The infection rate of early cranioplasty was lower than that of late cranioplasty (7% vs. 20%; p=0.02). Early cranioplasty, non-metal allograft materials, re-operation before cranioplasty and younger age were the significant factors in the infection rate after cranioplasty (p<0.05). Especially allograft was a significant risk factor of infection (odds ratio, 12.4; 95% confidence interval, 3.24–47.33; p<0.01). Younger age was also a significant risk factor of infection after cranioplasty by multivariable analysis (odds ratio, 0.96; 95% confidence interval, 0.96–0.99; p=0.02). CONCLUSION: Early cranioplasty did not increase the infection rate in this study. The use of non-metal allograft materials influenced a more important role in infection in cranioplasty. Actually, timing itself was not a significant risk factor in multivariate analysis. So the early cranioplasty may bring better outcomes in cognitive functions or wound without raising the infection rate.

Results of Isotope Cisternography in 175 Patients with a Suspected Hydrocephalus / 대한신경손상학회지

OBJECTIVE: Normal pressure hydrocephalus (NPH) is a syndrome characterized by gait disturbance, memory impairment and urinary incontinence. The isotope cisternography (ICG) became less useful because of low accuracy and complications. We tried to evaluate the safety and value of the ICG. METHODS: We retrospectively collected data on ICG of 175 consecutive patients with a suspected hydrocephalus. We classified the ICG into four types by the ventricular reflux and circulation time. The ventricular size was measured by Evans index and the width of the third ventricle. RESULTS: There were three complications including one case of paraplegia. Type 4 was the most common type, observed in 53%. Type 3 (33%), type 2 (7%), and type 1 (7%) were observed less often. Type 4 was more common in patients with large ventricles. Types of the ICG were not related to the causes of hydrocephalus, gender, or age of the patients. Shunting was more frequently performed in type 4 (71%), compared to type 1 (17%), type 2 (33%), and type 3 (46%). Surgery was more common when the cause was vascular. After the shunt surgery, 33.0% were graded as the improved. Although there were some improvements even in the not-improved patients, they still needed many helps. The improvement was related to the preoperative state. CONCLUSION: ICG may bring a serious complication, however the incidence is very low. Although the predictability of response rate on the shunting is doubtful, ICG is a cheap and useful tool to select surgical candidates in NPH.

Transcranial Direct Middle Meningeal Artery Puncture for the Onyx Embolization of Dural Arteriovenous Fistula Involving the Superior Sagittal Sinus

A 66-year-old woman presented with intermittent paraparesis and generalized tonic-clonic seizure. Cerebral angiography demonstrated dural arteriovenous fistula (AVF) involving superior sagittal sinus (SSS), which was associated with SSS occlusion on the posterior one third. The dural AVF was fed by bilateral middle meningeal arteries (MMAs), superficial temporal arteries (STAs) and occipital arteries with marked retrograde cortical venous reflux. Transfemoral arterial Onyx embolization was performed through right MMA and STA, but it was not successful, which resulted in partial obliteration of dural AVF because of tortuous MMA preventing the microcatheter from reaching the fistula closely enough. Second procedure was performed through left MMA accessed by direct MMA puncture following small decortications of cranium overlying the MMA using diamond drill one week later. Microcatheter could be located far distally to the fistula through 5 F sheath placed into the MMA and complete obliteration of dural AVF was achieved using 3.9 cc of Onyx.

Iatrogenic Carotid-Cavernous Fistula after Stent Assisted Coil Embolization of Posterior Communicating Artery Aneurysm

Stent assisted coiling (SAC) is a useful technique for the treatment of wide necked complex aneurysm. As the frequency of SAC increases, stent-related complications such as thromboembolism, aneurysm rupture, and vessel rupture have been reported. However, to the best of our knowledge, carotid-cavernous fistula (CCF) after SAC has never been reported. The authors experienced a case of direct CCF after a SAC procedure for treatment of a complex posterior communicating artery (PCoA) aneurysm regrowth, which was treated by clip ligation 12 years before. The patient was managed conservatively and angiograms performed three months after the procedure showed the complete obliteration of the left PcoA aneurysm and the spontaneous disappearance of CCF. Navigation of Solitaire stent lumen with microcatheter can cause unexpected arterial injury, especially when the proximal tip is placed in the curved portion. It seems to be desirable to place the proximal tip of Solitaire stent in the straight portion whenever possible to reduce the risk of inadvertent arterial injury which might be caused by future navigation of stent lumen.

Morphometric Study of the Anterior Thalamoperforating Arteries

OBJECTIVE: To evaluate the morphometry of the anterior thalamoperforating arteries (ATPA). METHODS: A microanatomical study was performed in 79 specimens from 42 formalin-fixed adult cadaver brains. The origins of the ATPAs were divided into anterior, middle, and posterior segments according to the crowding pattern. The morphometry of the ATPAs, including the premammillary artery (PMA), were examined under a surgical microscope. RESULTS: The anterior and middle segments of the ATPAs arose at mean intervals of 1.75+/-1.62 mm and 5.86+/-2.05 mm from the internal carotid artery (ICA), and the interval between these segments was a mean of 3.17+/-1.64 mm. The posterior segment arose at a mean interval of 2.43+/-1.46 mm from the posterior cerebral artery (PCA), and the interval between the middle and posterior segments was a mean of 3.45+/-1.39 mm. The mean numbers of perforators were 2.66+/-1.19, 3.03+/-1.84, and 1.67+/-0.98 in the anterior, middle, and posterior segments, respectively. The PMA originated from the middle segment in 66% of cases. A perforator-free zone was located >2 mm from the ICA in 30.4% and >2 mm from the PCA in 67.1% of cases. CONCLUSION: Most perforators arose from the anterior and middle segments, within the anterior two-thirds of the posterior communicating artery (PCoA). The safest perforator-free zone was located closest to the PCA. These anatomical findings may be helpful to verify safety when treating lesions around the PCoA and in the interpeduncular fossa.

Thromboembolic Event Detected by Diffusion Weighted Magnetic Resonance Imaging After Coil Embolization of Cerebral Aneurysms

OBJECTIVE: The purpose of this study was to evaluate the occurrence rate of diffusion positive lesions (DPLs), and to assess the peri-procedural risk factors for the occurrence of DPLs in patients who underwent coil embolization of cerebral aneurysms. MATERIALS AND METHODS: A total of 304 saccular aneurysms were embolized during a seven-year period from Jan 2007 to Dec 2013. Of these, postoperative diffusion-weighted images were obtained in 186 procedures. There were 100 ruptured aneurysm and 86 unruptured aneurysms. The coiling procedures were as follows: simple coiling in 96, balloon assisted coiling (BAC) in 39, and stent assisted coiling (SAC) in 51 aneurysms. Clinical, angiographic and procedural factors were analyzed in relation to the occurrence of DPLs. RESULTS: Overall, DPLs were observed in 50.5%. In unruptured aneurysms, DPLs occurred in 23.5% of BAC, 41.9% of SAC and 57.7% of simple coiling (p = 0.08). Among ruptured aneurysms, DPLs occurred in 63.6% of BAC, 62.5% of SAC and 54.3% of simple coiling (p = 0.71). DPLs had a tendency to increase in ruptured aneurysms compared with unruptured aneurysms (57% vs. 43%, p = 0.077). Logistic regression analysis revealed that age > 55 years was the only independent risk factor for the occurrence of DPLs. CONCLUSION: DPLs occured more frequently in ruptured aneurysm and at an older age. Although most DPLs are asymptomatic, careful manipulation of cerebral or extracerebral arteries using various endovascular devices is important to reducing the occurrence of DPLs. BAC appeared to reduce occurrence of TE events in patient with unruptured aneurysm.

Chronic Low Back Pain in Young Korean Urban Males: The Life-Time Prevalence and Its Impact on Health Related Quality of Life

OBJECTIVE: We assessed the life-time prevalence (LTP) of chronic low back pain (LBP) in young Korean males. We also evaluated the relationship between lumbar spinal lesions and their health related quality-of-life (HRQOL). METHODS: A cross-sectional, self-reported survey was conducted in Korean males (aged 19-year-old) who underwent physical examinations for the conscript. We examined 3331 examinees in November 2014. We included 2411 subjects, who accepted to participate this study without any comorbidities. We interviewed using simple binary questions for their LBP experience and chronicity. HRQOL was assessed by Short-Form Health-Survey-36 (SF-36) in chronic LBP and healthy control groups. Radiological assessment was performed in chronic LBP group to determine whether there were any pathological causes of their symptoms. RESULTS: The LTP of chronic LBP was 13.4%. Most (71.7%) of them didn't have any lumbar spinal lesions (i.e., non-specific chronic LBP). The SF-36 subscale and summary scores were significantly lower in subjects with chronic LBP. Between specific and non-specific chronic LBP group, all physical and mental subscale scores were significantly lower in specific chronic LBP group, except mental health (MH) subscale score. In MH subscale and mental component summary score, statistical significant differences didn't appear between two groups (p=0.154, 0.126). CONCLUSION: In Korean males 19 years of age, the LTP of chronic LBP was 13.4%, and more than two-thirds were non-specific chronic LBP. Chronic LBP had a significant impact on HRQOL. The presence of lumbar spinal pathoanatomical lesions affected mainly on the physical aspect of HRQOL. It influenced little on the mental health.

Surgical Decision Making for the Elderly Patients in Severe Head Injuries

OBJECTIVE: Age is a strong predictor of mortality in traumatic brain injuries. A surgical decision making is difficult especially for the elderly patients with severe head injuries. We studied so-called 'withholding a life-saving surgery' over a two year period at a university hospital. METHODS: We collected data from 227 elderly patients. In 35 patients with Glasgow Coma Score 3-8, 28 patients had lesions that required operation. A life-saving surgery was withheld in 15 patients either by doctors and/or the families (Group A). Surgery was performed in 13 patients (Group B). We retrospectively examined the medical records and radiological findings of these 28 patients. We calculated the predicted probability of 6 month mortality (IPM) and 6 month unfavorable outcome (IPU) to compare the result of decision by the International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT) calculator. RESULTS: Types of the mass lesion did not affect on the surgical decision making. None of the motor score 1 underwent surgery, while all patients with reactive pupils underwent surgery. Causes of injury or episodes of hypoxia/hypotension might have affected on the decision making, however, their role was not distinct. All patients in the group A died. In the group B, the outcome was unfavorable in 11 of 13 patients. Patients with high IPM or IPU were more common in group A than group B. Wrong decisions brought futile cares. CONCLUSION: Ethical training and developing decision-making skills are necessary including shared decision making.

Endovascular Treatment for Ruptured Distal Anterior Inferior Cerebellar Artery Aneurysm

A 42-year-old woman presented with Hunt and Hess grade (HHG) III subarachnoid hemorrhage (SAH) caused by a ruptured left distal anterior inferior cerebellar artery (AICA) aneurysm. Computed tomography showed a thin SAH on the cerebellopontine angle cistern, and small vermian intracerebral hemorrhage and intraventricular hemorrhage in the fourth ventricle. Digital subtraction angiography revealed the aneurysm on the postmeatal segment of left distal AICA, a branching point of rostrolateral and caudomedial branch of the left distal AICA. Despite thin caliber, tortuous running course and far distal location, the AICA aneurysm was obliterated successfully with endovascular coils without compromising AICA flow. However, the patient developed left side sensorineural hearing loss postoperatively, in spite of definite patency of distal AICA on the final angiogram. She was discharged home without neurologic sequela except hearing loss and tinnitus. Endovascular treatment of distal AICA aneurysm, beyond the meatal loop, is feasible while preserving the AICA flow. However, because the cochlear hair cell is vulnerable to ischemia, unilateral hearing loss can occur, possibly caused by the temporary occlusion of AICA flow by microcatheter during endovascular treatment.

Multiple Densities of the Chronic Subdural Hematoma in CT Scans

OBJECTIVE: Density of the chronic subdural hematoma (cSDH) is variable. It often appears to be mixed density. Multiple densities of cSDH may result from multiple episodes of trauma. We investigated the frequency of mixed density and the causes of head injuries representing each density. METHODS: We could collect 242 cases of chronic SDH. The cSDHs were classified into four groups; hypodensity, homogeneous isodensity, layered type, and mixed type on the basis of CT scans. RESULTS: The density of cSDH was isodense in 115 patients, hypodense in 31 patients, mixed in 79 cases, and layered in 17 cases. The cSDH was on the left side in 115 patients, on the right side in 70 patients, and bilateral in 40 patients. The history of trauma was identifiable in 122 patients. The etiology could be identified in 67.7% of the hypodense hematomas, while it was obscure in 59.5% of the mixed hematomas. CONCLUSION: Mixed density of cSDH results from multiple episodes of trauma, usually in the aged. It is hard to remember all the trivial traumas for the patients with the mixed density cSDHs. Although there were membranes within the mixed density hematomas, burr-holes were usually enough to drain the hematomas.