Role of Magnetic Resonance Imaging in the Screening of Closed Spinal Dysraphism.

Closed spinal dysraphism (CSD) encompasses a heterogeneous group of spinal cord deformities, which can be accompanied by several types of skin stigmata. These skin stigmata may include inconspicuous features, such as sacral dimples and deformed gluteal clefts, but the association between such mild skin stigmata and CSD is uncertain. This study aimed to reevaluate the indication for magnetic resonance imaging (MRI) in patients with skin stigmata while considering the indication for surgery. A retrospective analysis was conducted on magnetic resonance images of 1255 asymptomatic children with skin stigmata between 2003 and 2015. Skin stigmata classification was based on medical chart data. All subtypes of CSDs except for filum terminale lipomas (FTL), FTL thicker than 2 mm or with low conus medullaris, were considered to meet the surgical indication. CSD prevalence was estimated while considering the surgical indications and assessed after excluding all FTL cases. Skin stigmata were classified into seven types, dimple, deformed gluteal cleft, hair, subcutaneous mass, appendage, discoloration, and protruding bone, and included 1056 isolated and 199 complex ones. The prevalence of CSD was 19.5%, 6.8%, and 0.5% among patients with isolated dimples (n = 881) and 13.9%, 5.8%, and 0.7% among those with isolated deformed gluteal clefts (n = 136) for all cases, surgical indications, and patients without FTL, respectively. Dimples and deformed gluteal clefts had a low prevalence of CSD requiring surgical intervention, and cases without FTL were rare. Asymptomatic patients with mild skin stigmata may not require immediate MRI.

Technical evolution of pediatric neurosurgery: moyamoya disease.

Moyamoya disease (MMD) is a rare steno-occlusive disease of the bilateral internal carotid arteries that predominantly occurs in East Asia. Since the first description of the MMD by Suzuki and Takaku in 1969, significant advances have been made in both basic and clinical understanding of the disease. The incidence and prevalence of pediatric MMD have increased, potentially due to improved detection rates. The advancement of neuroimaging techniques has enabled MRI-based diagnostics and detailed visualization of the vessel wall. Various methods of surgical treatments are successful in pediatric MMD patients, and recent studies emphasize the importance of reducing postoperative complications since the goal of MMD surgery is to prevent future cerebral infarction and hemorrhage. Long-term outcomes following appropriate surgical treatment in pediatric MMD patients have shown promising results, including favorable outcomes in very young patients. Further studies with a large patient cohort are needed to establish individualized risk group stratification for determining the optimal timing of surgical treatment and to conduct multidisciplinary outcome assessments.

[Moyamoya Disease in Infants and Toddlers].

Treatment for moyamoya disease in infants and toddlers is challenging, because of the progressiveness of the disease. Revascularization surgery is the first-line therapy and should be performed as early as possible after diagnosis to prevent additional cerebral infarction. This review describes in detail the changes in the new "Diagnostic Criteria 2021 for moyamoya disease", and discusses the concept of treatment including indirect and combined bypass surgery in infants and toddlers. Surgical technique and perioperative management based on our experience are also precisely described.

Ocular Ischemic Syndrome due to Internal Carotid Artery Occlusion with Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF-1) is associated with multiple vascular abnormalities, including internal carotid artery (ICA) stenosis/occlusion. Depending on the site of stenosis/occlusion of the ICA, both cerebral circulation and ocular circulation can be impaired. We describe a rare pediatric case of ocular ischemic syndrome (OIS) due to ICA occlusion in NF-1. The patient diagnosed with NF-1 suffered right ICA occlusion at 12 years of age, and developed right dense vitreous hemorrhage due to OIS at 13 years of age. The patient underwent right cerebral revascularization surgery to improve cerebral and ocular ischemia, but the visual acuity of the right eye did not improve. This case suggests that attention should be paid not only to cerebral ischemia but also to ocular ischemia in patients with ICA stenosis/occlusion of NF-1. Surgical interventions such as cerebral revascularization surgery should be considered in the early stages of OIS to protect visual function, and careful follow-up is required.

Retethering risk in pediatric spinal lipoma of the conus medullaris.

OBJECTIVE: Lipoma of the conus medullaris (LCM) causes neurological symptoms known as tethered cord syndrome (TCS). The symptoms can be seen at diagnosis and during long-term follow-up. In this report, pediatric patients with LCMs who underwent untethering surgery, under the policy of performing surgery if diagnosed regardless of symptoms, were retrospectively reviewed to evaluate long-term surgical outcomes. Possible risk factors for retethered cord syndrome (ReTCS) were evaluated in the long-term follow-up period. METHODS: A total of 51 consecutive pediatric patients with LCMs who underwent a first untethering surgery and were followed for > 100 months were retrospectively analyzed. The surgery was performed with the partial removal technique. Pre- and postoperative clinical and radiological data were reviewed to analyze the outcomes of surgery and identify potential risk factors for ReTCS. RESULTS: During follow-up, 12 patients experienced neurological deterioration due to ReTCS. The overall 10-year and 15-year progression-free survival rates were 82.3% and 75.1%, respectively. On univariate analysis, a lipoma type of lipomyelomeningocele (OR 11, 95% CI 2.50-48.4; p = 0.0014), patient age at the time of surgery (OR 0.41, 95% CI 0.14-1.18; p = 0.0070), and the mean patient growth rate after surgery (OR 2.00, 95% CI 1.12-3.41; p = 0.0040) were significant factors associated with ReTCS. Cox proportional hazard models showed that a lipoma type of lipomyelomeningocele (HR 5.16, 95% CI 1.54-20.1; p = 0.010) and the mean growth rate after surgery (HR 1.88, 95% CI 1.00-3.50; p = 0.040) were significantly associated with the occurrence of ReTCS. CONCLUSIONS: More complex lesions and a high patient growth rate after surgery seemed to indicate increased risk of ReTCS. Larger prospective studies and registries are needed to define the risks of ReTCS more adequately.

Preoperative Risks of Cerebral Infarction in Pediatric Moyamoya Disease.

Background and Purpose: In pediatric moyamoya disease, there have been few reports of the risk factors for preoperative cerebral infarction, especially during the waiting period before surgery. The clinical and radiological findings of surgically treated pediatric moyamoya patients were evaluated to analyze the risk factors for cerebral infarction seen from onset to surgery. Methods: Between August 2003 and September 2019, 120 hemispheres of 71 patients under 18 years of age with moyamoya disease were surgically treated by direct and indirect bypass procedures. The mean age of all surgical hemispheres at diagnosis was 6.7±3.9 years (6 months­17 years). The potential risk factors for preoperative infarction were examined statistically. Results: Multivariate logistic regression analysis showed that risk factors for infarction at the time of diagnosis were age at diagnosis (odds ratio [OR], 0.68 [95% CI, 0.57­0.82]; P<0.0001) and the magnetic resonance angiography (MRA) score (OR, 2.29 [95% CI, 1.40­3.75]; P=0.001). Univariate analysis showed that risk factors for infarction while waiting for surgery were age at diagnosis (OR, 0.61 [95% CI, 0.46­0.80]; P<0.0001), the MRA score (OR, 1.75 [95% CI, 1.26­2.41]; P=0.0003), and onset of infarction (OR, 40.4 [95% CI, 5.08­322.3]; P<0.0001). Multiple comparisons showed that patients under 4 years of age were at a significantly high risk of infarction at the time of diagnosis and while waiting for surgery. Time from diagnosis to surgery of >2 months was a significant risk factor for infarction while waiting for surgery in patients under 6 years of age. Conclusions: Young age at diagnosis and a high MRA score may be associated with rapid disease progression and result in preoperative infarction. We recommend that surgery be performed within 2 months of diagnosis for the patients under 4 years of age with a high MRA score (>5) and cerebral infarction. Further study is needed to define the optimal timing of surgery.

Progressive Hydrocephalus after Endoscopic Third Ventriculostomy in Pediatric Patients with Blake's Pouch Cyst.

The pathophysiology and optimal treatment for hydrocephalus with Blake's pouch cyst (BPC) remain controversial. The authors present two pediatric cases of hydrocephalus associated with BPC, in which the patients' hydrocephalus progressed after endoscopic third ventriculostomy (ETV), despite a patent stoma of the third ventricular floor. Case 1: A 4-year-old girl with delayed gait development was diagnosed with BPC-associated hydrocephalus and received ETV. Postoperatively, the patient presented headaches and nausea. Computed tomography (CT) scans demonstrated larger ventricles than those observed on the preoperative images. Because phase-contrast cine magnetic resonance imaging (MRI) and constructive interference in steady state (CISS) MRI revealed patent cerebrospinal fluid (CSF) flow at the third ventricular floor level, a ventriculoperitoneal shunt (VPS) was placed using a programmable pressure valve to treat the hydrocephalus. Case 2: A 6-year-old girl with newly developed repeated convulsive seizures was diagnosed with BPC-associated hydrocephalus and received ETV. Phase-contrast cine MRI on the 5th postoperative day showed hyperdynamic CSF flow at the third ventricular floor level. She also developed vomiting and headache 6 weeks after ETV. CT scans demonstrated much larger tetraventricular hydrocephalus than that observed on the preoperative images. VPS placement improved her hydrocephalus. Referencing the previous literature, we discuss the CSF dynamics and the mechanism of BPC-associated hydrocephalus, focusing on the third ventricular floor bulging. We hope our experience will help elucidate the pathophysiology and treatment strategies for BPC-associated hydrocephalus.

Prosthesis Used in Microvascular Decompressions: A Multicenter Survey in Japan Focusing on Adverse Events.

OBJECTIVE: To investigate the characteristics of materials used as prostheses for microvascular decompression surgery (MVDs) in Japan and their possible adverse events (AEs) to determine preferable materials for MVDs. METHODS: A questionnaire was sent to all members of the Japanese Society for MVDs, and answers were obtained from 59 institutions. RESULTS: Among a total of 2789 MVDs, 1088 operations for trigeminal neuralgia, 1670 for hemifacial spasm, and 31 others, including 117 reoperations, were performed between April 2011 and March 2014. Nonabsorbable material was used in 96.5% of MVDs, including polytetrafluoroethylene (PTFE) (80.5%), polyurethane (11.9%), expanded PTFE (2.1%), and silk thread (1.47%). The use of absorbable materials, including fibrin glue (87.5%), cellulose (13.5%), gelatin (4,77%), and collagen (1.76%), was reported. The major combinations were PTFE with fibrin glue (58.7%) followed by PTFE alone (7.60%). Eighty-eight AEs in 85 (3.2%) cases were reported among 2672 first operations. AEs included 51 central nervous system dysfunctions, 15 wound infections/dehiscence, and 10 others, which were presumed to be related to the intraoperative procedure. Among relatively high-, moderate-, and low-volume centers, there were no significant differences in the frequency of AEs (P = 0.077). Tissue-prosthesis adhesion and/or granuloma formation were reported in 13 cases of 117 reoperations. The incidence of adhesion-related recurrence was 11.1% of all reoperations. CONCLUSIONS: The number of AEs was quite low in this survey, and intradural use of any prosthesis reported in this paper might be justified; however, further development of easily handled and less-adhesive prosthesis materials is awaited.

Posterior cerebral artery stenosis and posterior circulation revascularization surgery in pediatric patients with moyamoya disease.

OBJECTIVE Some pediatric patients with moyamoya disease (MMD) present with posterior cerebral artery (PCA) stenosis before and after anterior circulation revascularization surgery and require posterior circulation revascularization surgery. This study evaluated the factors associated with PCA stenosis and assessed the efficacy of posterior circulation revascularization surgery, including occipital artery (OA)-PCA bypass, in pediatric patients with MMD. METHODS The presence of PCA stenosis before and after anterior circulation revascularization surgery and its clinical characteristics were investigated in 62 pediatric patients (< 16 years of age) with MMD. RESULTS Twenty-three pediatric patients (37%) with MMD presented with PCA stenosis at the time of the initial diagnosis. A strong correlation between the presence of infarction and PCA stenosis before anterior revascularization was observed (p < 0.001). In addition, progressive PCA stenosis was observed in 12 patients (19.4%) after anterior revascularization. The presence of infarction and a younger age at the time of initial diagnosis were risk factors for progressive PCA stenosis after anterior revascularization (p < 0.001 and p = 0.002, respectively). Posterior circulation revascularization surgery, including OA-PCA bypass, was performed in 9 of the 12 patients with progressive PCA stenosis, all of whom showed symptomatic and/or radiological improvement. CONCLUSIONS PCA stenosis is an important clinical factor related to poor prognosis in pediatric MMD. One should be aware of the possibility of progressive PCA stenosis during the postoperative follow-up period and consider performing posterior circulation revascularization surgery.

Minimally Invasive Surgical Approach to Filum Lipoma.

Filum terminale lipoma (FTL) causes various spinal symptoms known as tethered cord syndrome. The treatment for FTL is surgical untethering by sectioning the FTL, which can prevent symptom progression and often results in improvement of symptoms. This report describes a minimally invasive surgical strategy that we have introduced for FTL sectioning. The pediatric patients with FTL since 2007 were treated using this minimally invasive surgical strategy, which we refer to as an interlaminar approach (ILA). In summary, the surgical technique involves: minimal skin incision to expose the unilateral ligamentum flavum in the lower lumbar region; ligamentum flavum incision to expose the dural sac, and dural incision followed by identification and sectioning of the filum. Postoperatively, no bed rest was required. Prior to introducing ILA, we had used standard one level laminectomy/laminotomy (LL) with more than 1 week of postsurgical bed rest until 2007, providing an adequate control group for the benefit of the ILA. A total of 49 consecutive patients were treated using ILA. While 37 patients were treated using LL. Surgical complications that need surgery were seen only in one patient, who developed cerebrospinal fluid (CSF) leak in LL patients. No retethering or additional neurological symptoms were seen during follow-up. All patients complained of minimal postsurgical back pain, but no patients required postoperative bed rest in ILA patients, while LL patients need postsurgical bed rest because of back pain. The ILA strategy provides the advantage of a minimal tissue injury, associated with minimal postoperative pain, blood loss, and bed rest.

Shunt placement after cyst fenestration for middle cranial fossa arachnoid cysts in children.

OBJECT Some pediatric patients with middle cranial fossa arachnoid cysts present with symptoms of increased intracranial pressure (ICP) and require shunt placement after a cyst fenestration. However, factors concerning increased ICP after fenestration followed by shunt placement have not been elucidated. This study evaluated factors that are associated with shunt placement following cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. METHODS Twenty-six pediatric patients with middle cranial fossa arachnoid cysts who were surgically treated at a single institution between 2004 and 2013 were retrospectively identified. The surgical indications for middle cranial fossa arachnoid cysts were as follows: 1) arachnoid cysts associated with symptoms such as headache and abnormally enlarging head circumference; 2) progressively expanding arachnoid cysts; and 3) large arachnoid cysts such as Galassi Type III. A cyst fenestration was performed as a first-line treatment, and shunt placement was required if symptoms associated with increased ICP were found following fenestration. The risk factors evaluated included age, sex, presenting symptoms, the presence of head enlargement, progressive cyst expansion, and subdural hematoma/hygroma. RESULTS Four patients (15.4%) required shunt placement after cyst fenestration. Younger age, abnormal head enlargement, and progressive cyst expansion before fenestration were significantly associated with the need for shunt placement following fenestration. Arachnoid cysts decreased in size in 22 patients (84.6%) after fenestration and/or shunt placement. The presence of symptoms was not associated with postoperative cyst size in this study. CONCLUSIONS In this study, younger age, abnormal head enlargement, and progressive cyst expansion were risk factors for shunt placement after cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. It is important to consider that cyst fenestration may not be effective because of a latent derangement of CSF circulation in patients with these risk factors.

Surgical indication and outcome in patients with postoperative retethered cord syndrome.

OBJECT: After untethering of spinal dysraphism, some patients present with neurological deterioration, defined as retethered cord syndrome. It is known that surgical untethering is an option for improving the symptoms of retethered cord syndrome. Previous reports have shown that postoperative improvement in retethered cord syndrome was noted in the majority of patients presenting with pain, and in more patients with motor weakness than in those with urological symptoms. The authors speculate that subjective symptoms may be detected while symptoms are still reversible. In contrast, changes in urological function are less easy to diagnose, and delays in treatment may be complicated by advanced symptoms. In this study, patients with retethered cord syndrome were evaluated to investigate the benefits of performing routine urodynamic study to detect detrusor overactivity, which is considered to be a subclinical change of urological function, and to investigate the efficacy of early untethering surgery on the symptoms of retethered cord syndrome. METHODS: Surgical indications and outcomes of 78 untethering operations (20 for myelomeningocele, 58 for spinal lipoma) for retethered cord syndrome were examined. Diagnosis of retethered cord syndrome was defined by a multidisciplinary spina bifida team, and included routine urodynamic study. RESULTS: Preoperative symptoms included urological symptoms (70%), lower-extremity symptoms (45%), and others. The most frequent urological symptom was detrusor overactivity detected by urodynamic study (88.7%). Urinary incontinence was only found in 9.4% of patients. Postoperatively, progressive motor weakness improved in all patients, and sensory symptoms improved in 94%. Urological symptoms improved in 80% of the patients with urinary incontinence and in 75% of the patients with detrusor overactivity. Postoperative urodynamic study showed a significant increase in bladder volume (p < 0.05). The most common complication was temporary lower leg paresthesia that recovered at follow-up. Aggravated dysuria was noted in 3 patients. CONCLUSIONS: Early untethering operations offer symptomatic relief to patients with retethered cord syndrome. Urodynamic study findings, especially detrusor overactivity, are considered to be the most significant indicators for early diagnosis of retethered cord syndrome.

A proposal for standardized analysis of the results of microvascular decompression for trigeminal neuralgia and hemifacial spasm.

BACKGROUND: The purpose of this study was to evaluate and analyze overall postoperative results from microvascular decompression (MVD) by combining the cure rate of symptoms with the complication rate. A new scoring system for obtaining objective surgical results from MVD for trigeminal neuralgia (TN) and hemifacial spasm (HFS) is proposed to document treatment results using consistent criteria in a standardized manner. METHOD: Surgical results combining complications , if any, were obtained from a questionnaire sent to patients who had undergone surgery for TN or HFS in recent years and had been followed-up for more than 1 year after surgery (TN patients, n = 54; HFS patients, n = 81) When surgical outcome is complete resolution of symptoms, the efficacy of surgery (E) is designated E-0, but when moderate symptoms are still persist postoperatively, the score is designated E-2. When no complications are seen after surgery, the complication score (C) is C-0, while the score is C-2 if troublesome complications remain. In addition, total evaluation of the results (T) is judged by combining the E and C scores. For example, when E is 0, and C is C-2, the total evaluation is scored as T-2, which is diagnosed as fair. FINDINGS: The response rate of the questionnaire was 80.7% (109/135). Overall surgical data were evaluated and analyzed using our new scoring system. Analysis of the collected data revealed an outcome of T-0 was 70% (35/50 patients) and T-1 was 24% (12/50) and T-2 was 6% (3/50) in TN, whereas in HFS, T-0 was 61% (36/59) and T-1 was 27.1% (16/59) and T-2 was 6.8% (4/59) and T-3 was 5.1% (3/59). CONCLUSION: The total results of MVD should be evaluated and analyzed by combining the cure rate of symptoms together with the complication rate. This new scoring system could allow much more objective analysis of the results of following MVD. Adopting this scoring system to objectively judge treatment results for TN and HFS, individual surgeons can compare their own overall surgical results with those of other institutes. Comparative results of MVD can also be provided to patients considering therapy to allow informed decision-making on the basis of good quality evidence.

Postoperative neurological deterioration in pediatric moyamoya disease: watershed shift and hyperperfusion.

OBJECT: Young patients with moyamoya disease frequently exhibit extensive cerebral infarction at the time of initial presentation, and even in the early postoperative period. To investigate clinical characteristics in the early postoperative period, the authors prospectively analyzed findings of MR imaging, MR angiography, and SPECT before and after surgery. The authors focused in particular on how postoperative neurological deterioration occurred. METHODS: Between August 2005 and June 2009, 22 patients younger than 18 years of age with moyamoya disease were treated at Miyagi Children's Hospital. The mean patient age (+/- SD) was 8.58 +/- 4.55 years (range 2-17 years). Superficial temporal artery-middle cerebral artery bypass and indirect bypass of encephalosynangiosis between the brain surface and the temporal muscle, galea, and dura mater were performed in 35 hemispheres. Magnetic resonance imaging and MR angiography were performed before surgery, at 7 days postoperatively, and 3-6 months after surgery. A (123)I-isopropyl iodoamphetamine SPECT scan was also obtained pre- and postoperatively. RESULTS: During the postoperative period, neurological deterioration was observed after 15 operations (10 cases of motor paresis, 1 of aphasia, and 4 of sensory disturbance) in 13 patients. All symptoms had resolved by the time of discharge, except in 2 patients who suffered cerebral infarction. All patients exhibited disappearance (94.3%) or reduction (5.7%) of transient ischemic attacks (TIAs) during the follow-up period. Perioperative studies revealed 2 different types of radiological findings, focal uptake decrease on SPECT indicative of cerebral ischemia due to dynamic change in cerebral hemodynamics caused by bypass flow, the so-called watershed shift, and perioperative edematous lesions on MR imaging due to cerebral hyperperfusion. The frequent occurrence of preoperative TIAs was significantly associated with watershed shift, whereas preoperative MR imaging findings and preoperative SPECT findings were not. Age at operation was the only factor significantly associated with postoperative hyperperfusion. CONCLUSIONS: In young patients, moyamoya disease exhibits rapid progression, resulting in poor clinical outcome. The risk of postoperative neurological deterioration in very young moyamoya patients with frequent TIAs should be noted. The findings in this study showed that direct bypass is not completely safe in patients with moyamoya disease because it causes dynamic change in postoperative cerebral hemodynamics.

Embryopathogenetic surgicoanatomical classification of dysraphism and surgical outcome of spinal lipoma: a nationwide multicenter cooperative study in Japan.

OBJECT: The natural history of asymptomatic spinal lipoma in infancy remains unclear, and the indication for the prophylactic untethering operation is still debatable. To address this question, a multicenter cooperative study for the treatment of spinal lipoma was performed by the 7 most active institutions in neurosurgical care for spina bifida in Japan between 2001 and 2005. METHODS: Patients were classified using the embryopathogenetic surgicoanatomical classification. Their neurosurgical postoperative course was analyzed using the Spina Bifida Neurological Scale. Among 261 patients, 159 were asymptomatic and 102 were symptomatic. RESULTS: Of the 136 patients for whom prophylactic surgeries were performed, 135 remained asymptomatic and only 1 (0.4%) of the 261 patients presented with mild sensory disturbance. Mild foot deformity was identified in 1 (4.3%) of 23 conservatively observed patients. Of 100 symptomatic patients, deterioration after surgery was seen in 6%, and improvement in 44%. Complete resolution of symptoms was seen in only 14.2%. Filar types for patients > 3 years old improved in Spina Bifida Neurological Scale scores from 12.3 to 14.0. The mean age of symptomatic patients with lipomyelomeningocele was the youngest of all (1.3 years), which indicates lipomyelomeningocele may deteriorate in early infancy. Improvements from surgery were seen for all types of lipoma except the caudal type, presenting at an older mean age (15 years). CONCLUSIONS: A low rate of postsurgical worsening indicates that surgeries for asymptomatic and symptomatic lipomas are safe. Surgeries done after the onset of symptoms seldom cure the patients. These two results support early untethering for any kind of lipoma; however, further study of the natural history is required.

Additional surgery for postoperative ischemic symptoms in patients with moyamoya disease: the effectiveness of occipital artery-posterior cerebral artery bypass with an indirect procedure: technical case report.

OBJECTIVE: In patients with moyamoya disease, surgery to revascularize the ischemic brain is a recommended treatment. However, there are a few patients who require additional revascularization surgery because of progression of the disease. Even patients who show no postoperative ischemic symptoms at first may experience late deterioration. We performed additional surgery for such lesions using occipital artery (OA)-posterior cerebral artery (PCA) bypass with indirect revascularization. The efficacy of the procedure is reported. METHODS: We treated 3 patients with moyamoya disease who showed a transient ischemic attack after revascularization surgery. Three female patients, ranging in age from 6.0 to 35.2 years (mean age, 23.8 years) at the time of surgery, with ischemic symptoms (leg monoparesis in 2, visual impairment in 1) underwent the additional revascularization procedure. Preoperatively, all patients underwent indirect and/or direct revascularization surgery for initial treatment. All patients showed progression of the disease, especially in the PCA. OA-PCA bypass with encephalogaleodurosynangiosis and burr hole surgery were performed for postoperative ischemic symptoms. RESULTS: All patients showed clinical and radiological improvement. The transient ischemic attack was improved in all 3 patients. They did not complain of transient ischemic attack in the recent follow-up period. Follow-up magnetic resonance imaging showed no additional cerebral infarction. Magnetic resonance angiography showed widening of the OA and development of peripheral collateral vessels. Postoperative single-photon emission computed tomographic studies showed marked increase of uptake in both anterior cerebral artery and PCA territories. Cerebral vasodilatory capacity evaluated by an acetazolamide test also showed marked improvement. One patient showed postoperative cerebral edema as a result of focal cerebral hyperperfusion. CONCLUSION: OA-PCA anastomosis with indirect revascularization was effective for postoperative ischemia that showed symptoms in the anterior cerebral artery and PCA territories as a result of progression of a PCA lesion.

Post-operative changes of cerebral circulation and metabolism in the acute stage of low-grade aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Pre- and post-operative cerebral circulation and metabolism were evaluated in patients with low-grade acute aneurysmal subarachnoid hemorrhage (SAH) who underwent early surgery to investigate the effects on brain dysfunction. METHODS: Positron emission tomography (PET) was performed to measure the regional cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), oxygen extraction fraction (OEF) and cerebral blood volume in four patients (one male and three females, mean age: 60.3 years) with low-grade SAH within 30 hours of onset. Post-operative PET was performed on the seventh post-operative day. No patient suffered clinical deterioration during the study. Pre-operative PET scans demonstrated significant global reduction of CBF and CMRO2, compared to 16 normal control subjects, and no significant change in OEF. CBF and CMRO2 reduction post-operatively improved to the normal control values. Post-operative OEF was significantly increased compared to the normal control value. CONCLUSIONS: Patients with low-grade SAH have impairment of cerebral circulation and metabolism in the acute period, which improves after surgery. Early surgery for low-grade SAH, necessary to avoid rerupture of the aneurysm, did not worsen the impairment of cerebral circulation and metabolism. However, measures to protect the brain from perioperative damage are necessary to achieve the optimum outcome.

Spinal hamartoma associated with spinal dysraphism.

OBJECTS: The aims of the study were (1) to review the pathological findings of spinal lipomatous masses associated with congenital spinal dysraphism and (2) to discuss the pathological diagnosis. METHODS: The pathological records of 47 patients at our institution were reviewed, and three illustrative cases were presented. CONCLUSION: Spinal tumorous lesions associated with spinal dysraphism have been traditionally described as lipoma since they are composed mostly of fatty tissue. However, they are different from lipomas arising in other part of the body in that they often contain various tissues of ecto- and mesodermal origin. In our study, we detected such heterotopic components in 24 out of 47 cases. Although they are also similar to teratoma, it is generally accepted that they are malformative lesions which lack neoplastic potential. We therefore should diagnose them as hamartoma rather than lipoma or teratoma.