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1.  Intracranial Extension of Spinal Subarachnoid Hematoma Causing Severe Cerebral Vasospasm 
Spinal subarachnoid hemorrhages (SAH) can extend into the intracranial subarachnoid space, but, severe cerebral vasospasm is rare complication of the extension of intracranial SAH from a spinal subarachnoid hematoma. A 67-year-old woman started anticoagulant therapy for unstable angina. The next day, she developed severe back pain and paraplegia. MRI showed intradural and extramedullar low signal intensity at the T2-3, consistent with intradural hematoma. High signal intensity was also noted in the spinal cord from C5 to T4. We removed subarachnoid hematoma compressing the spinal cord. The following day, the patient complained of severe headache. Brain CT revealed SAH around both parietal lobes. Three days later, her consciousness decreased and left hemiplegia also developed. Brain MRI demonstrated multiple cerebral infarctions, mainly in the right posterior cerebral artery territory, left parietal lobe and right watershed area. Conventional cerebral angiography confirmed diffuse severe vasospasm of the cerebral arteries. After intensive care for a month, the patient was transferred to the rehabilitation department. After 6 months, neurologic deterioration improved partially. We speculate that surgeons should anticipate possible delayed neurological complications due to cerebral vasospasm if intracranial SAH is detected after spinal subarachnoid hematoma.
PMCID: PMC4303733  PMID: 25628817
Spinal subarachnoid hematoma; Intracranial subarachnoid hemorrhage; Vasospasm; Cerebral infarction
2.  Modic Degenerative Marrow Changes in the Thoracic Spine : A Single Center Experience 
The purposes of this study were to evaluate the prevalence, types, and locations of Modic changes (MCs) in the thoracic spine in a large number of subjects, and to investigate the relation between the distributions of MCs and disc herniations (DHs) in the thoracic spine.
Two experienced musculoskeletal radiologists assessed the presence of MCs and DHs by consensus in the thoracic MRIs of 144 patients with non-specific back pain. Patient ages ranged from 22 to 88 years (mean=53.3±14.66 years), and 72 were female (50%). The prevalence, distribution, relation of MCs and DHs was recorded.
MC was observed in 8 of the 144 patients (5.6%) and 10 of 1728 segments (0.58%). The most common MC was type II. Of the 8 patients exhibiting MC, 6 had type II (75.0%), and 2 had mixed MCs (type I/II or type II/III). MCs were distributed mainly at the mid-thoracic level (from T5/6 to T9/10). DH was detected in 18 patients (12.5%), 36 of 1728 segments (2.1%). Of the 10 segments exhibiting MC, 5 had DHs at the same level (50.0%). Accordingly, DH was strongly associated with MC (p=0.000).
A low prevalence of MC was observed in the thoracic spine, and type II MC predominated. The low prevalence of MC in the thoracic spine suggests that it was caused by a relative lack of mobility as compared with the cervical and lumbar spines. And DHs were found to be strongly associated with MCs even in the thoracic spine.
PMCID: PMC3772284  PMID: 24044078
Prevalence; Modic change; Thoracic spine; Disc herniation
3.  Clinical Application of Gamma Knife Dose Verification Method in Multiple Brain Tumors : Modified Variable Ellipsoid Modeling Technique 
The Leksell Gamma Knife® (LGK) is based on a single-fraction high dose treatment strategy. Therefore, independent verification of the Leksell GammaPlan® (LGP) is important for ensuring patient safety and minimizing the risk of treatment errors. Although several verification techniques have been previously developed and reported, no method has ever been tested statistically on multiple LGK target treatments. The purpose of this study was to perform and to evaluate the accuracy of a verification method (modified variable ellipsoid modeling technique, MVEMT) for multiple target treatments.
A total of 500 locations in 10 consecutive patients with multiple brain tumor targets were included in this study. We compared the data from an LGP planning system and MVEMT in terms of dose at random points, maximal dose points, and target volumes. All data was analyzed by t-test and the Bland-Altman plot, which are statistical methods used to compare two different measurement techniques.
No statistical difference in dose at the 500 random points was observed between LGP and MVEMT. Differences in maximal dose ranged from -2.4% to 6.1%. An average distance of 1.6 mm between the maximal dose points was observed when comparing the two methods.
Statistical analyses demonstrated that MVEMT was in excellent agreement with LGP when planning for radiosurgery involving multiple target treatments. MVEMT is a useful, independent tool for planning multiple target treatment that provides statistically identical data to that produced by LGP. Findings from the present study indicate that MVEMT can be used as a reference dose verification system for multiple tumors.
PMCID: PMC3611052  PMID: 23560174
Brain tumor; Gamma Knife; Radiation dose; Radiosurgery
4.  Imaging Findings of Solitary Spinal Bony Lesions and the Differential Diagnosis of Benign and Malignant Lesions 
The purpose of this study was to present the MRI and CT findings of solitary spinal bone lesions (SSBLs) with the aims of aiding the differential diagnoses of malignant tumors and benign lesions, and proposing a diagnostic strategy for obscure SSBLs.
The authors retrospectively reviewed the imaging findings of 19 patients with an obscure SSBL on MRI at our hospital from January 1994 to April 2011. The 19 patients were divided to benign groups and malignant groups according to final diagnosis. MRI and CT findings were evaluated and the results of additional work-up studies were conducted to achieve a differential diagnosis.
At final diagnoses, 10 (52.6%) of the 19 SSBLs were malignant tumors and 9 (47.4%) were benign lesions. The malignant tumors included 6 metastatic cancers, 3 multiple myelomas, and 1 chordoma, and the benign lesions included 4 osteomyelitis, 2 hemangiomas, 2 nonspecific chronic inflammations, and 1 giant cell tumor. No MRI characteristics examined was found to be significantly different in the benign and malignant groups. Reactive sclerotic change was observed by CT in 1 (10.0%) of the 10 malignant lesions and in 7 (77.8%) of the 9 benign lesions (p=0.005).
Approximately half of the obscure SSBLs were malignant tumors. CT and MRI findings in combination may aid the differential diagnosis of obscure SSBLs. In particular, sclerotic change on CT images was an important finding implying benign lesion. Finally, we suggest a possible diagnostic strategy for obscure SSBLs on MRI.
PMCID: PMC3467370  PMID: 23091671
Solitary spinal bone lesion; Differential diagnosis; MRI; CT; benign lesion; Malignant lesion
5.  In-Stent Stenosis of Stent-Assisted Coil Embolization of the Supraclinoid Internal Carotid Artery Aneurysm 
The intracranial stent functions primarily to prevent protrusion of coils into the parent vessel during the embolization of wide-necked cerebral aneurysms and might also reduce aneurysm recanalization rate. In spite of these advantages, little is known about the long-term interaction of the stent with the parent vessel wall. We present a rare case of severe in-stent stenosis occurring as a delayed complication of Neuroform stent-assisted coil embolization of an unruptured intracranial aneurysm.
PMCID: PMC3424179  PMID: 22949968
Cerebral aneurysms; In-stent stenosis; Stent
6.  The Obturator Guiding Technique in Percutaneous Endoscopic Lumbar Discectomy 
In conventional percutaneous disc surgery, introducing instruments into disc space starts by inserting a guide needle into the triangular working zone. However, landing the guide needle tip on the annular window is a challenging step in endoscopic discectomy. Surgeons tend to repeat the needling procedure to reach an optimal position on the annular target. Obturator guiding technique is a modification of standard endoscopic lumbar discectomy, in which, obturator is used to access triangular working zone instead of a guide needle. Obturator guiding technique provides more vivid feedback and easy manipulation. This technique decreases the steps of inserting instruments and takes safer route from the peritoneum.
PMCID: PMC3358610  PMID: 22639720
Diskectomy; Percutaneous; Intervertebral disc disease; Endoscope
7.  The Effect of Body Mass Index on Intra-Abdominal Pressure and Blood Loss in Lumbar Spine Surgery 
The purpose of this prospective study was to evaluate the effects of body mass index (BMI) on intra-abdominal pressure (IAP) and intraoperative blood loss (IBL) during lumbar spinal surgery.
Thirty patients scheduled for single level posterior lumbar interbody fusion were allocated equally to a normal group (Group 1, BMI;18.5-22.9 kg/m2), an overweight group (Group 2, BMI; 23-24.9 kg/m2), and an obese group (Group 3, BMI; 25.0-29.9 kg/m2) according to BMI. IAP was measured using a urinary bladder catheter; 1) supine after anesthesia induction, 2) prone at skin incision, 3) prone at the end of surgery. In addition, IBL was also measured in the three groups.
IAP in the supine position was not significantly different in groups 1, 2, and 3 (2.7 mm Hg, 3.0 mm Hg, and 4.2 mm Hg, respectively) (p=0.258), and IAP in the prone position at incision increased to 7.8 mm Hg, 8.2 mm Hg, and 10.4 mm Hg, respectively, in the three groups, and these intergroup differences were significant, especially for Group 3 (p=0.000). IAP at the end of surgery was slightly lower (7.0 mm Hg, 7.7 mm Hg, and 9.2 mm Hg, respectively). IBLs were not significantly different between the three groups. However, IBLs were found to increase with IAP in the prone position (p=0.022) and BMI (p<0.05).
These results show that BMI affects IAP in the prone position more than in the supine position during lumbar spinal surgery. In addition, IBLs were found to increase with IAP in the prone position and with BMI. Thus, IBLs can be expected to be higher in morbidly obese patients due to an increased IAP.
PMCID: PMC3322212  PMID: 22500198
Body mass index; Intra-abdominal pressure; Urinary bladder pressure; Intraoperative blood loss; Posterior lumbar interbody fusion
8.  Computer-Assisted Modified Mid-Sacrectomy for En Bloc Resection of Chordoma and Preservation of Bladder Function 
A 67-year-old woman presented for evaluation of severe coccygeal pain. The computed tomography scans and magnetic resonance imaging showed an asymmetric midline sacral tumor invading the right lower portion of S2. To preserve both S2 nerve roots and to obtain negative surgical margins, a modified mid-sacrectomy with an aid of a computed navigation system was performed. The sacral tumor was excised en bloc with negative tumor margins. Both S2 nerve roots were preserved and additional reconstruction was not necessary because of minimal resection of the sacroiliac joint. We report a case of a sacral chordoma which was excised en bloc with adequate surgical margins by a computer-assisted modified mid-sacrectomy. The computed navigation system may be a useful tool for tumor targeting and safe osteotomies in sacral tumor surgery via the posterior only approach.
PMCID: PMC3272515  PMID: 22323941
Sacral chordoma; Sacrectomy; En bloc resection; Computed navigation system
9.  Cervical Fibrous Dysplasia Presenting as a Pathologic Fracture in an Older Patient 
Vertebral involvement of fibrous dysplasia (FD) is rare, especially in the cervical spine. Moreover, cervical FD presenting as a pathologic fracture in older patients is extremely rare. We report a case of symptomatic cervical FD associated with pathologic fracture in a 63-year-old man. The patient presented with progressive weakness of the left arm and pain in the shoulder and arm. Radiologic studies revealed a collapsed and typical 'ground glass' radiolucency of C4. Multiple lytic lesions involved the odontoid process of C2 and the body, left pedicle, and posterior elements of C4. Combined anterior and posterior decompression and reconstruction were performed. Post-operatively, the histopathologic examination confirmed FD. On the post-operative follow-up examination, the neurologic deficits had completely resolved.
PMCID: PMC3206278  PMID: 22053236
Fibrous dysplasia; Cervical spine; Elderly
10.  Primary Extramedullary Ependymoma of the Cervical Spine : Case Report and Review of the Literature 
Intradural extramedullary (IDEM) ependymomas occur very rarely and little has been reported about their clinical characteristics. The authors present a case of a 57-year-old woman with an IDEM ependymoma. She was referred for the evaluation of a 4-month history of increasing neck pain and muscular weakness of the left extremities. Magnetic resonance imaging (MRI) of the cervical spine demonstrated an IDEM tumor with spinal cord compression. At the time of surgery, an encapsulated IDEM tumor without a dural attachment or medullary infiltration was noted, but the tumor capsule adherent to the spinal cord and root was left in place to minimize the risk of neurological sequelae. Histologic examination revealed a benign classic ependymoma. The post-operative course was uneventful and radiotherapy was performed. The patient showed an excellent clinical recovery, with no recurrence after 5 years of follow-up.
PMCID: PMC3159884  PMID: 21892408
Intradural extramedullary; Ependymoma; Cervical spine
11.  Inferiorly Migrated Disc Fragment at T1 Body Treated by T1 Transcorporeal Approach 
Upper thoracic vertebral bodies are difficult to access using standard anterior approaches. It may require sternotomy and claviculectomy, which carries significant possibility of morbidities. We report a case of inferiorly migrated cervicothoracic junction disc treated successfully by anterior upper-vertebral transcorporeal approach. This specific technique obviated the need of sternotomy, created favorable working space and saved the motion segment at cervicothoracic junction. This report is the first transcorporeal approach to a disc fragment at T1-2 space without fusion.
PMCID: PMC3070898  PMID: 21494366
Intervertebral disc; Transcorporeal approach; Upper thoracic vertebral disc
12.  Non-Dura Based Intaspinal Clear Cell Meningioma 
A 34-year-old female patient was presented with leg and hip pain for 6 months as well as voiding difficulty for 1 year. Magnetic resonance imaging revealed a well-demarcated mass lesion at L2-3. The mass was hypo-intense on T1- and T2-weighted images with homogeneous gadolinium enhancement. Surgery was performed with the presumptive diagnosis of intradural extramedullary meningioma. Complete tumor removal was possible due to lack of dural adhesion of the tumor. Histologic diagnosis was clear cell meningioma, a rare and newly included World Health Organization classification of meningioma usually affecting younger patients. During postoperative 2 years, the patient has shown no evidence of recurrence. We report a rare case of cauda equina clear cell meningioma without any dural attachment.
PMCID: PMC3070901  PMID: 21494369
Clear cell meningioma; Spinal meningioma; World Health Organization classification; Younger patients; Cauda equina
13.  Hypopharyngeal Wall Exposure within the Surgical Field : The Role of Axial Rotation of the Thyroid Cartilage during Anterior Cervical Surgery 
Esophageal/hypopharyngeal injury can be a disastrous complication of anterior cervical surgery. The amount of hypopharyngeal wall exposure within the surgical field has not been studied. The objective of this study is to evaluate the chance of hypopharyngeal wall exposure by measuring the amount of axial rotation of the thyroid cartilage (ARTC) and posterior projection of the hypopharynx (PPH).
The study was prospectively designed using intraoperative ultrasonography. We measured the amount of ARTC in 27 cases. The amount of posterior projection of the hypopharynx (PPH) also was measured on pre-operative CT and compared at three different levels; the superior border of the thyroid cartilage (SBTC), cricoarytenoid joint and tip of inferior horn of the thyroid cartilage (TIHTC). The presence of air density was also checked on the same levels.
The angle of ARTC ranged from -6.9° to 29.7°, with no statistical difference between the upper and lower cervical group. The amount of PPH was increased caudally. Air densities were observed in 26 cases at the SBTC, but none at the TIHTC.
Within the confines of the thyroid cartilage, surgeons are required to pay more attention to the status of hypopharynx/esophagus near the inferior horn of the thyroid cartilage. The hypopharynx/esophagus at the TIHTC is more likely to be exposed than at the upper and middle part of the thyroid cartilage, which may increase the risk of injury by pressure. Surgeons should be aware of the fact that the visceral component at C6-T1 surgeries also rotates as much as when the thyroid cartilage is engaged with a retractor. The esophagus at lower cervical levels warrants more careful retraction because it is not protected by the thyroid cartilage.
PMCID: PMC3030079  PMID: 21286476
Anterior cervical surgery; Thyroid cartilage; Hypopharynx; Esophageal injury
14.  Isolated Recurrence of Intracranial Granulocytic Sarcoma Mimicking a Falx Meningioma in Acute Myeloblastic Leukemia 
Intracranial granulocytic sarcomas are rare tumors, which are composed of immature granulocytic cells. Although it has been well known that these tumors are associated with acute myeloblastic leukemia (AML), they have been almost always related to bone marrow relapse. However, isolated recurrence of granulocytic sarcoma following complete remission from prior AML is extremely rare, especially in the central nervous system. A 44-year-old male presented with isolated recurrence of granulocytic sarcoma mimicking a falx meningioma two years after complete remission by allogenic peripheral blood stem cell transfusion (PBSCT) in the acute myelomonoblastic leukemia (FAB, M4). Because of depressed mental state and mass effect, total surgical resection was performed. Pathological findings were compatible with the granulocytic sarcoma. There was no evidence of leukemic relapse in the peripheral blood. We suggest that this phenomenon can be explained by the hypothesis that a certain barrier effect such as blood brain barrier might lead to the proliferation of intracranial leukemic cells which metastasized before PBSCT.
PMCID: PMC2883061  PMID: 20539800
Chloroma; Granulocytic sarcoma; Leukemia
15.  Lumbar Osteochondroma Arising from Spondylolytic L3 Lamina 
Osteochondromas are common, benign tumors in the long bones, but osteochondromas are rare in the vertebrae. Most vertebral osteochondromas arise from the cervical or upper thoracic spine. However, lumbar osteochondromas have rarely been reported. In this report, a rare case of a lumbar osteochondroma arising from the spondylolytic L3 lamina in a 57-year-old woman is presented. She also had a ruptured disc and lumbar canal stenosis at L4-5-S1. The osteochondroma was completely removed and a posterior lumbar interbody fusion and instrumentation were performed. Considering the rarity of osteochondromas in the lumbar vertebrae, especially the L3 vertebra, it is possible that the pre-existing lumbar spondylolysis or spondylolisthesis was one of the factors affecting the occurrence or progression of the osteochondroma.
PMCID: PMC2864829  PMID: 20461177
Lumbar osteochondroma; Spondylolysis
16.  The Variable Ellipsoid Modeling Technique as a Verification Method for the Treatment Planning System of Gamma Knife Radiosurgery 
The secondary verification of Leksell Gamma Knife treatment planning system (LGP) (which is the primary verification system) is extremely important in order to minimize the risk of treatment errors. Although prior methods have been developed to verify maximum dose and treatment time, none have studied maximum dose coordinates and treatment volume.
We simulated the skull shape as an ellipsoid with its center at the junction between the mammillary bodies and the brain stem. The radiation depths of the beamlets emitted from 201 collimators were calculated based on the relationship between this ellipsoid and a single beamlet expressed as a straight line. A computer program was coded to execute the algorithm. A database system was adopted to log the doses for 31×31×31 or 29,791 matrix points allowing for future queries to be made of the matrix of interest.
When we compared the parameters in seven patients, all parameters showed good correlation. The number of matrix points with a dose higher than 30% of the maximal dose was within ± 2% of LGP. The 50% dose volume, which is generally the target volume, differs maximally by 4.2%. The difference of the maximal dose ranges from 0.7% to 7%.
Based on the results, the variable ellipsoid modeling technique or variable ellipsoid modeling technique (VEMT) can be a useful and independent tool to verify the important parameters of LGP and make up for LGP.
PMCID: PMC2836448  PMID: 20224712
Gamma knife radiosurgery; Treatment planning system; Quality assurance
17.  Fusiform Intracanalicular Ophthalmic Artery Aneurysm; Case Report and Review of Literature 
A 35-year-old man's vision had progressively deteriorated over a 3-month period. His left visual acuity was 5/20. Enhanced orbital computed tomographic (CT) scans revealed a fusiform dilatation of the ophthalmic artery in the left optic canal. Cerebral Angiography revealed a fusiform aneurysm on the left ophthalmic artery in the optic canal, measuring 6.2 × 4.6 mm in size. Four days after admission, visual acuity dropped to hand-motion. Endovascular treatment was chosen and a microcatheter was guided into the proximal segment of the ophthalmic artery. Using 4 detachable coils, parent artery occlusion was done. Three months after the intervention, the visual acuity in his left eye improved to 20/20. Dramatic recovery of visual acuity is exceptional with an ophthalmic artery trunk aneurysm. When an occlusion of the proximal ophthalmic artery is the only treatment option in such a situation, the endovascular occlusion of the proximal ophthalmic artery is quite feasible in the sense that it does not require any optic nerve manipulation.
PMCID: PMC2588290  PMID: 19096656
Detachable coil; Fusiform aneurysm; Intracanalicular portion; Ophthalmic artery trunk aneurysm

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