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Lumbar foraminal stenosis is a common disorder, with surgical treatment varying from simple decompression to interbody fusion. It is often associated with degenerative lumbar scoliosis, but the effects of scoliosis on outcomes are unclear. The objectives of this study were to clarify long-term outcomes after microsurgical decompression of lumbar foraminal stenosis through Wiltse’s approach and to determine the effects of scoliosis on these outcomes. A total of 86 consecutive patients with lumbar foraminal stenosis were prospectively followed after microsurgical decompression. They were categorized in multiple subcohorts with follow-up durations ranging from 6 months to 5 years. Outcomes were assessed using the Short Form 36 questionnaire (average physical scores and bodily pain scores). Local Cobb angle of the operative segment was measured preoperatively, and its effects on outcomes were analyzed. Average physical scores improved significantly from 33.8 (95% confidence interval [CI]: 29.1–38.5) preoperatively to 59.5 (95% CI: 54.6–64.3) at 6 months postoperatively and remained improved for 5 years. Bodily pain scores improved significantly from 23.7 (95% CI: 18.7–28.6) preoperatively to 56.3 (95% CI: 51.2–61.6) at 6 months postoperatively and remained improved for 5 years. Patients with preoperative scoliosis (local Cobb angle >10 degrees) had poorer outcomes: average physical scores were worse by 9.6 points (p = 0.07) and bodily pain scores were worse by 12.1 points (p = 0.02), compared with patients without scoliosis (local Cobb angle ≤10 degrees). Microsurgical foraminal decompression produced overall excellent outcomes in patients with lumbar foraminal stenosis. Preoperative scoliosis attenuated these beneficial effects.

A wide lateral viewing angle is often necessary for spinal surgery. However, the skin and paraspinal muscles limit this angle in the traditional posterior midline approach. This article describes a simple, less-invasive approach that provides good lateral viewing angles to spinal lesions. The approach consisted of (1) a horizontal skin incision, (2) unilateral dissection and exposure of the laminae, (3) a horizontal fascial incision, and (4) application of retractors in the longitudinal direction with a minimal incision on the multifidus muscle. We successfully used this approach on 24 patients with various spinal diseases. The pathology of the lesions included nine schwannomas, five meningiomas, four ossification of ligamentum flavum (OLF), three malignant tumors, and three others. There were nine cervical, twelve thoracic, two lumbar, and one sacral lesions. We could achieve gross total removal in most cases without significant complications. The approach provided an excellent surgical field for removing ventrally located tumors with minimal cord retraction. This simple technique will be a valuable addition to the armamentarium of spine surgeons.

Background In cervical expansive laminoplasty, precise placement of lateral gutters is important. Placing them too medially results in suboptimal canal expansion, and placing them too laterally results in facet joint violation. However, precise placement is often difficult. Methods We have included a simple procedure called probe laminotomy in cervical expansive laminoplasty since 2013. This technique consisted of identifying the location of the pedicles through a small laminotomy with medial facetectomy before making lateral gutters. A case-control study was performed to compare the achieved postoperative canal area and duration of surgery between the original technique and the added probe laminotomy. Results The postoperative canal area was 21% larger in the probe laminotomy group compared with the standard technique group (P = 0.0003). There was no significant difference in duration of surgery between the groups. Conclusions This technique facilitated more precise placement of the lateral gutter in cervical expansive laminoplasty, which resulted in a larger postoperative canal. This technique should be considered as an option in cervical expansive laminoplasty.

Au-CuPc nanocomposite films were prepared by simultaneous evaporation of Au and CuPc with various Au and CuPc concentrations. Microstructural analysis of Au-CuPc films revealed elongated Au cluster formation from isolated Au nanoclusters with increasing Au concentration associated with coalescence of Au clusters. Au-CuPc films with different compositions were employed as interlayer in Al/n-Si Schottky diode. Barrier height and series resistance of the Al/n-Si Schottky diode with Au-CuPc interlayer decreased with increasing Au concentration. This could be associated with the enhancement of electron tunneling between neighboring clusters due to decrease in spacing of Au clusters and formation of conducting paths through the composite material. Interface state density of the Al/n-Si Schottky diode with Au-CuPc interlayer increased with increasing Au concentration. This might be because the inclusion of metal decreases the crystallinity and crystal size of the polymer matrix accompanied by the formation of local defect sites at the places of metal nucleation.

Background To approach a ventral spinal pathology, a lateral viewing angle is often required. However, lateral approaches to the spine are usually more technically demanding and require a certain amount of surgical expertise. In this report, we describe a simple and easy technique to obtain the lateral viewing angle to the ventral spinal pathology. Case Description The technique is demonstrated in a ventrally located meningioma at the C2 level. Axial magnetic resonance imaging showed a square posterior shift of the spinal cord with little lateral space, which necessitated a more lateral viewing angle than the conventional posterior approach. With the patient in a prone position, we made a horizontal skin incision at the level of C2 and unilaterally exposed the right side of the C1 and C2 laminae. We then made a small perpendicular incision on the medial portion of the paravertebral muscles, which we retracted longitudinally. This approach provided an unobstructed lateral view toward the spinal cord. Following a gross total removal of the tumor with minimal cord retraction, the patient made an uneventful recovery. Her preoperative neurologic symptoms completely resolved in 2 months. No significant muscle atrophy was observed on postoperative magnetic resonance imaging at 3 months. There was no long-term complication related to the muscle incision at 1-year follow-up. Conclusion The posterior paramedian approach is a simple and versatile technique to obtain lateral viewing angle to the spine and useful for approaching lesions residing ventral to the spinal cord.

Background The standard surgical treatment for adult isthmic spondylolisthesis consists of various techniques of arthrodesis supplemented with instrumentation. However, the superiority of this strategy has not been irrefutably proved. Considering the risk associated with the instrumentation surgery, examining a less invasive approach is justified. Methods We describe a series of 9 patients with adult isthmic spondylolisthesis, in whom we microsurgically decompressed the responsible nerve root in the intervertebral foramen through the posterolateral intermuscular approach. Technical details specific to isthmic spondylolisthesis were reviewed. The 2-year outcome was assessed with Short Form 36 and visual analog scale scores. Results The mean age of the patients was 68 ± 7 years (standard deviation [SD]). The mean slip rate of spondylolisthesis measured on the preoperative lumbar radiography was 20% ± 12% (SD). All patients successfully underwent the procedure without complications. All the examined scores remained significantly better than the preoperative values 2 years after surgery; the mean visual analog scale score decreased from 7.8 ± 2.8 (SD) preoperatively to 2.8 ± 1.4 (SD) at 2 years ( P = 0.008), average physical score of Short Form 36 improved from 33.1 ± 9.7 to 52.5 ± 9.4 ( P = 0.001), and the bodily pain score improved from 28.0 ± 13.5 to 55.1 ± 9.7 ( P = 0.001). Conclusions Microsurgical decompression through the posterolateral intermuscular approach was effective in producing good 2-year outcome in patients with adult isthmic spondylolisthesis. This procedure may be considered as a less invasive alternative in the surgical treatment of adult isthmic spondylolisthesis.

Background Dumbbell-shaped spinal schwannomas with intradural and extradural components are associated with higher complication rates. This may be in part due to epineurial dissection of the extradural component, which inevitably damages the functioning nerve fibers beneath the epineurium and may lead to dural defects that are often difficult to repair. Objective The objective was to describe a radical intracapsular dissection technique that provides a simpler operative field with no need for dural repair and a better chance of preserving functioning nerve fibers. Methods The technique comprised the following: 1) exposure of the tumor while preserving spinal stability; 2) a single incision encompassing the dura and epineurium; 3) microsurgical dissection of the tumor just beneath the epineurium, preserving the viable nerve fibers; and 4) primary closure of the duroepineurial incision. We describe a case series of 7 patients in whom this type of tumor was excised using this technique. Results Gross total excision was achieved in 5 patients. In 1 patient with a large paravertebral component, the remaining tumor was removed with an additional anterior approach. No cerebrospinal fluid leak was noted, and no recurrence was observed in the median follow-up period of 36 months. Conclusions The radical intracapsular dissection technique described herein represents an alternative technique for the removal of dumbbell-shaped spinal schwannomas with intradural and extradural components.

Objective Although sagittal spinal balance is known to affect the outcome of spinal deformity surgery, its effect on simple decompression surgery is not well understood. Materials and Methods Patients who underwent unilateral laminotomy for bilateral decompression for lumbar canal stenosis were prospectively enrolled in the study. Before surgery and 6 months after surgery, the following sagittal-alignment parameters were measured: lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), and sagittal vertical axis (SVA). At the same time, short-form 36 (SF-36) and Visual Analogue Scale (VAS) were estimated. The patients were divided into the poor postoperative physical score group (P_poor), good postoperative physical score group (P_good), poor postoperative VAS group (V_poor), or good postoperative VAS group (V_good). The postoperative spinopelvic parameters were compared between the physical score and VAS groups, respectively. Finally, we examined the correlation between the spinopelvic parameters and the outcome scores using scatter plots and linear regression analysis. Results Fifty-two patients were enrolled into the study. Although the spinopelvic parameters (LL, PT, PI-LL) significantly improved after surgery, the absolute values of improvement were relatively small. The postoperative spinopelvic parameters were significantly worse in the P_poor and the V_poor groups compared with the P_good and the V_good groups, respectively. The correlation analyses also showed that worse postoperative spinopelvic parameters correlated to worse outcome in SF-36 and VAS. Conclusions Sagittal spinal balance significantly affected the outcome of patients undergoing decompression surgery for lumbar canal stenosis, the knowledge of which may serve better patient management.

Objective Although sagittal spinal balance plays an important role in spinal deformity surgery, its role in decompression surgery for lumbar canal stenosis is not well understood. To investigate the hypothesis that sagittal spinal balance also plays a role in decompression surgery for lumbar canal stenosis, a prospective cohort study analyzing the correlation between preoperative lumbar lordosis and outcome was performed. Methods A cohort of 85 consecutive patients who underwent decompression for lumbar canal stenosis during the period 2007–2011 was analyzed. Standing lumbar x-rays and 36-item short form health survey questionnaires were obtained before and up to 2 years after surgery. Correlations between lumbar lordosis and 2 parameters of the 36-item short form health survey (average physical score and bodily pain score) were statistically analyzed using linear mixed effects models. Results There was a significant correlation between preoperative lumbar lordosis and the 2 outcome parameters at postoperative, 6-month, 1-year, and 2-year time points. A 10° increase of lumbar lordosis was associated with a 5-point improvement in average physical scores. This correlation was not present in preoperative scores. Conclusions This study showed that preoperative lumbar lordosis significantly influences the outcome of decompression surgery on lumbar canal stenosis.

Study design Prospective controlled trial. Objective To describe a newly found increased flow signal in phase-contrast magnetic resonance imaging observed in compressed segments of the spinal cord in patients with cervical spondylotic myelopathy (CSM). Summary of background data Derangement of cerebrospinal fluid movement in the spine is a well-known cause of syringomyelia. However, its possible role in CSM has not been studied well, despite the fact that similar derangement takes place in CSM. Methods In a consecutive series of 57 patients with CSM, cardiac-gated phase-contrast magnetic resonance imaging was analyzed. The amplitude of the flow signal obtained in the compressed segment of the spinal cord was compared with that obtained in the lesion-free C2 segment. It was also compared with controls obtained from 10 healthy volunteers. We also studied whether the amplitude was correlated with the severity of cervical canal stenosis, neurological symptoms, indication of surgery, and the presence of intramedullary high-intensity signal on T2-weighted images. In 33 patients who underwent decompression surgical procedures, we compared the amplitude of the flow signal between the preoperative and the postoperative study. Results Increased flow signal on phase-contrast study was seen in compressed segments of the spinal cord in 36 (63%) patients. The mean amplitude of the signal in the compressed segment was 0.64 ± 0.06 cm/s, whereas that in the C2 segment was 0.27 ± 0.01 and that in the controls was 0.28 ± 0.01. The flow signal linearly increased as the severity of canal stenosis increased. It significantly correlated with the symptom of upper-extremity dysesthesia, and the indication of surgery in these patients. The mean amplitude of the signal tended to be higher in those with intramedullary high-intensity signal than in those without. After decompression surgery, the increased flow signal was markedly diminished, and returned to a level comparable with the controls. Conclusion Phase-contrast imaging demonstrated increased flow signal in compressed segments of the spinal cord in a majority of patients with CSM. This suggests a possible role played by derangement of cerebrospinal fluid movement in CSM. It also suggests potential usefulness of phase-contrast study in the management of patients with CSM. Level of evidence 2.

Study design Prospective subcohort study. Objective To determine whether preoperative presence of degenerative spondylolisthesis worsens the outcome of patients undergoing unilateral laminotomy with bilateral decompression for lumbar stenosis. Summary of background data The standard surgical treatment for degenerative spondylolisthesis with lumbar stenosis is lumbar fusion after standard laminectomy. Although this strategy is widely adopted, it is not supported by class I evidence. This strategy assumes that degenerative spondylolisthesis worsens the outcome of laminectomy by causing postoperative instability. However, instability may be reduced or prevented by the use of less invasive decompression techniques. Methods To test the hypothesis that preoperative degenerative spondylolisthesis worsens the outcome of less invasive lumbar decompression, we performed a prospective cohort study of 165 consecutive patients who underwent unilateral laminotomy with bilateral decompression at our institution. The patients were prospectively followed with a standardized questionnaire, 36-Item Short Form Health Survey, and standing lumbar radiographs for a maximum follow-up period of 5 years. According to the presence or absence of degenerative spondylolisthesis, the patients were divided into 2 groups: an olisthesis group and a nonolisthesis group. Results The average 36-Item Short Form Health Survey physical score and bodily pain score improved substantially immediately after surgery. This improvement was maintained up to 5 years postoperatively. Progression of slippage was uncommon in both groups, with an overall incidence of 8% at 5 years of follow-up. There was no significant difference in the average physical score, the bodily pain score, or the rate of progression of slippage between the olisthesis and nonolisthesis groups. Conclusion Our study thus indicates that preoperative degenerative spondylolisthesis does not worsen the outcome of patients with lumbar stenosis undergoing unilateral laminotomy with bilateral decompression. These results suggest that lumbar fusion is often unnecessary in patients with degenerative spondylolisthesis and lumbar stenosis if the posterior decompression technique is unilateral laminotomy with bilateral decompression. Level of evidence 2.

INTRODUCTION Magnetic resonance perfusion imaging is considered to be available as grading of brain tumor and follow-up of brain treatment. One of the methods, arterial spin labeling (ASL), is a test that is useful for patients with renal impairment and contrast agent allergy and has low invasiveness because it does not use a contrast agent. However, there have been no reports of ASL in intraoperative MRI (iMRI). PURPOSE In this hospital iMRI (1.5T), it was examined whether ASL could be used to evaluate residual tumor in patients under general anesthesia. CASE STUDY A 75-year-old woman with right temporal lobe Glioblastoma. 43-year-old man, left temporal lobe Diffuse astrocytoma. All performed ASL at the time of MRI imaging for navigation before induction of anesthesia just before surgery and iMRI. In all cases, the blood pressure at iMRI was maintained, and Post Label Delay (PLD) calculated the optimal PLD from the carotid artery velocity measured by iMRI, and defined it as 1800–2200 ms, and performed ASL. RESULTS Actually, imaging by iMRI was almost difficult to visualize, and reflux was not recognized not only in the tumor but also in the gray matter. DISCUSSION The blood flow velocity measurement in the internal carotid artery is performed by the phase contrast method by intraoperative MRI, and the CBF decreases because propofol used during the operation decreases the CBF and also the brain metabolism. However, it has been suggested that it is one of the factors that make evaluation with ASL difficult. Although the iMRI of our hospital is 1.5 T, which is also a subject of investigation, it is thought that there is a limit to ASL imaging in the case of general anesthesia with propofol even from the calculated PLD. CONCLUSION ASL in iMRI at our hospital was not useful.

An arachnoid web is an abnormal formation of the arachnoid membrane in the spinal subarachnoid space that blocks CSF flow and causes syringomyelia. Although the precise mechanism of syrinx formation is unknown, dissection of the arachnoid web shrinks the syrinx and improves symptoms. Precisely determining the location of the arachnoid web is difficult preoperatively, however, because the fine structure generally cannot be visualized in usual MRI sequences. In this report the authors describe 2 cases of arachnoid web in which the web was preoperatively identified using quantitative CSF flow analysis of MRI. By analyzing cardiac-gated phase-contrast cine-mode MRI in multiple axial planes, the authors precisely localized the obstruction of CSF flow on the dorsal side of the spinal cord in both patients. This technique also revealed a 1-way valve-like function of the arachnoid webs. Imaging led to the early diagnosis of myelopathy related to the derangement of CSF flow and allowed the authors to successfully excise the webs through limited surgical exposure.

OBJECTIVE. Not much is known about surgical management of patients with chronic subdural haematoma (CSDH) treated with antiplatelet or anticoagulant therapy. The aims of this study were to review the surgical outcomes of patients with CSDH and assess the risks of antiplatelet in their surgical management. METHODS. We retrospectively analysed 448 consecutive patients with CSDH treated by one burr hole surgery at our institution. Among them, 58 patients had been on antiplatelet therapy. We discontinued the antiplatelet agents before surgery for all 58 patients. For 51 of these 58 patients (87.9%), early surgery was performed within 0-2 days from admission. We analysed the association between recurrence and patient characteristics, including history of antiplatelet or anticoagulant therapy; age (< 70 years or ≥ 70 years); side; history of angiotensin receptor II blocker, angiotensin converting enzyme blocker, or statin therapy; and previous medical history of head trauma, infarction, hypertension, diabetes mellitus, haemodialysis, seizure, cancer, or liver cirrhosis. RESULTS. Recurrence occurred in 40 patients (8.9%), which was one of the lowest rates in the literature. Univariate analysis showed that only the presence of bilateral haematomas was associated with increased recurrence rate while antiplatelet or anticoagulant therapy did not significantly increase recurrence risk. Also, the recurrence rate from early surgery (0-2 days from drug cessation) for patients on antiplatelet therapy was not significantly higher than that from elective surgery (5 days or more after drug cessation). However, multivariate analysis revealed that previous history of cerebral infarction was an independent risk factor for CSDH recurrence. CONCLUSIOns. Our overall data support the safety of early surgery for patients on the preoperative antiplatelet therapy without drug cessation or platelet infusion. Patients with a previous history of infarction may need to be closely followed regardless of antiplatelet or anticoagulant therapy.

Pilomyxoid astrocytoma (PMA) was recently classified as a variant of pilocytic astrocytoma (PA) with significantly more aggressive clinical features than those of PA. Like PAs, PMAs frequently arise in the chiasmatic/hypothalamic regions. The cerebellum is also a common site of occurrence for PAs but not for PMAs. We present the case of a 31-month-old boy with cerebellar PMA that showed rapid regrowth during the 3 months following the first subtotal resection. Gross total resection was achieved in the second surgery, followed by radiation to the tumor bed. During follow-up over the next 12 years, there has been no evidence of recurrence on magnetic resonance imaging. Although the prognosis of cerebellar PMAs remains unknown because of the paucity of cases, the relevant literature reports a more favorable outcome for cerebellar PMAs than for PMAs occurring at other locations. The results of this case study and a review of the relevant literature advocate radical resection, sometimes involving multiple surgeries, for cerebellar PMAs because gross total or near total resection is more feasible in the cerebellum than in other locations.

Background Surgical treatment of small, unruptured intracranial aneurysms remains a controversial topic. Recently, some authors have doubted the validity of the low rupture rates of small aneurysms reported in the literature and advocate aggressive surgical treatment of small unruptured aneurysms; however, some theoretical elucidation is necessary to determine whether such aggressive treatment is appropriate. Methods On certain theoretical assumptions, a simulation was performed to examine whether the low rupture rates for small aneurysms could produce a reasonable size distribution of ruptured aneurysms. Second, considering a hypothetical population in which all the unruptured aneurysms over a certain cut-off size are treated, the effect of this policy on reducing the incidence of subarachnoid hemorrhage (SAH) was mathematically analyzed. Then, the contribution of each individual operation to this reduction of SAH incidence was calculated. Results The low rupture rates reported in the literature produced a reasonable size distribution of ruptured aneurysms (median diameter of 10 mm) in the simulated population. The analysis of the treatment cut-off size showed that, as the cut-off size was progressively lowered to the range of 3–5 mm, further reduction of the incidence of SAH became almost negligible. The contribution of each individual surgery on unruptured aneurysms decreased rapidly as the aneurysm size decreased, and this reduction was proportional to the reduction of the rupture rate of the aneurysm. Conclusions These results suggest that we should be prudent in providing surgical treatment to small unruptured intracranial aneurysms.

Study design A retrospective study was conducted on the preoperative neurologic symptoms of patients with lumbar herniated discs. Objective To evaluate the possibility that the muscle innervation pattern and the sensory dermatomes of lumbar nerve roots are altered when a lumbosacral transitional vertebra is present. Summary of background data In 1962, McCulloch et al suggested with intraoperative recordings that the innervation pattern of the lumbar nerve roots may be altered when a lumbosacral transitional vertebra is present. However, this result was not repeated in the study by Young et al in 1983. Methods We retrospectively reviewed the charts of 62 consecutive patients who underwent microdiscectomy for lumbar herniated discs. Lumbarized S1 vertebra was present in 10 of 62 patients (16%). Among these 10 patients, 8 had herniated discs at L5-S1 compressing the S1 nerve root. In the 52 normally configured patients, 22 had herniated discs at L5-S1 compressing the S1 nerve root, and 15 had herniated discs at L4-L5 compressing the L5 nerve root. The preoperative neurologic symptoms caused by the S1 nerve root compression in the patients with lumbarized S1 vertebrae were compared with the symptoms caused by either L5 or S1 nerve root compression in the patients with normal configuration. Results The distribution of motor weakness caused by the S1 nerve root compression was significantly different between the patients with lumbarized S1 and those with the normal configuration. The motor weakness caused by the S1 root compression in the patients with lumbarized S1 was similar to that of the L5 nerve root compression in the normal configuration. Analysis of sensory symptoms showed similar results. Conclusions Our findings suggest that the function of lumbosacral nerve roots is altered in patients with lumbarized S1 so that the S1 nerve root serves the usual function of the L5 nerve root.

BACKGROUND Cauda equina syndrome is a relatively rare presenting symptom of lumbar herniated discs. Early operative decompression is advocated, but it may not always restore the bladder function. In such cases, knowing the long-term outcome of bladder or sphincter disturbances is quite useful in planning the management of these patients. METHODS Hospital records of patients operated on for lumbar herniated discs were reviewed. Charts and imaging studies of those patients who presented with classic cauda equina syndrome were analyzed. RESULTS There were 4 patients (2.8%) of 144 consecutive surgical series of lumbar disc herniation, whose presenting symptom was classic cauda equina syndrome. Postoperatively, the patients had been followed at the clinic for a mean period of 6.4 years. Certain characteristic findings were noted on patients’ neurological and radiological examinations. Although the recovery process of bladder function was very slow, taking months to years, all four patients achieved almost normal voiding with no major impairment of daily activities. CONCLUSIONS Even if short-term recovery of bladder function is poor after lumbar disc surgery for cauda equina syndrome, the long-term outcome is not necessarily so. We should follow up on these patients with such measures as intermittent self-catheterization and drug therapy, expecting slow but steady recovery of bladder and sphincter function.

Object. Management of patients with cerebral arteriovenous malformations (AVMs) is controversial. Excellent surgical results are obtained in patients with low Spetzler—Martin grades, whereas radiosurgery offers a good alternative with its high obliteration rate. In the absence of randomized studies, physicians must choose a treatment plan based on the currently available data. To support this decision-making process, a mathematical model designed to describe patient survival rates after each treatment option was developed.Methods. The theoretical survival curve in patients undergoing conventional surgery, radiosurgery, or observation was calculated. Theoretical life expectancies in patients with AVMs who presented at various initial ages were calculated for each treatment strategy. A systematic method was also developed to compare the estimated risks of various treatment combinations.Conclusions. Conventional surgery and radiosurgery definitely produced better survival rates than observation. In the comparison of surgery with radiosurgery, radiosurgery was equivalent to surgery with a combined morbidity and mortality rate of approximately 7% for a 20-year-old patient with an unruptured cerebral AVM. Data for other patient ages and treatment combinations are tabulated for use in determining the best treatment strategy. The authors believe that their analysis will provide logical support for the decision-making process involved in the treatment of patients with cerebral AVMs.

An arachnoid web is an abnormal formation of the arachnoid membrane in the spinal subarachnoid space that blocks CSF flow and causes syringomyelia. Although the precise mechanism of syrinx formation is unknown, dissection of the arachnoid web shrinks the syrinx and improves symptoms. Precisely determining the location of the arachnoid web is difficult preoperatively, however, because the fine structure generally cannot be visualized in usual MRI sequences. In this report the authors describe 2 cases of arachnoid web in which the web was preoperatively identified using quantitative CSF flow analysis of MRI. By analyzing cardiac-gated phase-contrast cine-mode MRI in multiple axial planes, the authors precisely localized the obstruction of CSF flow on the dorsal side of the spinal cord in both patients. This technique also revealed a 1-way valve-like function of the arachnoid webs. Imaging led to the early diagnosis of myelopathy related to the derangement of CSF flow and allowed the authors to successfully excise the webs through limited surgical exposure.

We envisage the efficacy and safety of intra-arterial infusion of fasudil hydrochloride (IAF) for symptomatic vasospasm (SVS) after subarachnoid hemorrhage (SAH). We compared results obtained from the groups that received selective IAF (a microcatheter inserted in intracranial arteries) and nonselective IAF (a microcatheter inserted in the cervical arteries). Glasgow Outcome Scale (GOS) value and computed tomographic (CT) score were used to evaluate clinical outcome and the extent of infarction due to delayed vasospasm.Over 2 years, 113 patients with SAH underwent clipping or coiling. Among them, 31 patients (27.4%) developed SVS. We performed nonselective IAF in 10 patients and selective IAF in 10 other patients. Eleven patients with SVS were treated without IAF. The data were statistically analyzed.By univariate linear regression analysis, IAF negatively correlated with CT score (p = 0.016), but IAF was significantly correlated with GOS (p = 0.035). By multiple regression analysis, Hunt and Kosnik grade and CT score significantly correlated with GOS.CT score significantly correlated with functional outcome. Although IAF, both selective and nonselective, was significantly effective for the treatment of delayed vasospasm, the former seemed to be more beneficial.

Despite a number of various hypotheses in the literature, the pathophysiology of syringomyelia is still not well understood. In this article, we report two cases of cervical syringomyelia not associated with Chiari I malformation. Both cases had a septum-like structure in the subarachnoid space on the dorsal side of the cord at the craniovertebral junction. Cardiac-gated phase-contrast cine-mode magnetic resonance imaging (MRI) demonstrated decreased cerebrospinal fluid (CSF) flow on the dorsal side of the spinal cord. Surgical excision of this septum, restoring the CSF flow, resulted in a prompt reduction of the syrinx size in both cases. Findings in these cases contradict the currently prevailing hypothesis of syrinx formation that postulate that the piston-like movement of the cerebellar tonsils enhance the pulsatile CSF flow in the spinal subarachnoid space, driving the CSF into the syrinx through the perivascular space of Virchow and Robin. The authors propose that a mechanism based on the decreased pulsatile CSF flow in the spinal subarachnoid space will be more suitable as a hypothesis in studying the pathophyisiology of syringomyelia. These cases also provide an important lesson in managing the patients with syringomyelia not associated with Chiari I malformation.

Retrospective review of 39 consecutive patients who underwent surgery for lumbar foraminal stenosis from 2004 to 2009.To evaluate the surgical technique and results of microsurgical posterolateral transmuscular approach for lumbar foraminal stenosis. In addition, to evaluate the diagnostic ability of coronal thin-sliced magnetic resonance imaging (MRI) for this disease.Lumbar foraminal stenosis is a disease caused by compression of the nerve root or dorsal root ganglion at the intervertebral foramen often causing severe sciatic pain. Although its diagnosis and surgical treatment has been described in the literature, posterolateral transmuscular approach has not been well described. In addition, definitive radiologic diagnosis of this disease is often difficult, which can lead to failed back syndrome.We retrospectively reviewed 39 consecutive patients who underwent surgery for lumbar foraminal stenosis from 2004 to 2009. Special thin-sliced coronal MRI was used for preoperative evaluation. Microsurgical posterolateral transmuscular approach was used to decompress the intervertebral foramen from the lateral side preserving most of the pars interarticularis and facet joint. Contralateral medial approach was used for cases with associated central canal stenosis. Surgical results were scored using MacNab scale. We compared the sensitivity and specificity of 2 MRI signs: (1) abnormal course of the nerve root inside the foramen on coronal slices, and (2) obliteration of the foramen on sagittal slices, and statistically analyzed them with the χ method.The MacNab score with the mean follow-up period of 25.5 months was excellent in 28 (72%), good in 5 (13%), fair in 3 (8%), and poor in 3 (8%) patients. There was no grave complication. Coronal MRI sign showed significantly better sensitivity and specificity.Posterolateral transmuscular approach with microsurgical foraminotomy provided excellent surgical results. Coronal thin-sliced MRI can be useful for diagnosis of this disease.

✓Extradural unroofing of the optic canal and subsequent mobilization of the optic nerve is a useful technique in the surgical treatment of parasellar tumors; however, the drilling procedure itself is associated with the risk of optic nerve damage. A safer technique would certainly be beneficial. The ultrasonic bone curette is a device developed in Japan for safer bone removal. Its use in intradural anterior clinoidectomy and opening of the internal auditory meatus has been reported before. In this article the authors describe their experience in using this device for extradural unroofing of the optic canal in patients with parasellar tumors. Between March 2002 and November 2004, the aforementioned technique was used in the treatment of eight patients with parasellar tumors. After undertaking a frontotemporal craniotomy and orbital osteotomy, an ultrasonic bone curette was used to unroof the optic canal via an epidural approach; in five cases anterior clinoidectomy was added subsequently. Using an ultrasonic bone curette, unroofing of the optic canal was completed safely and required much less expertise than that required for standard drilling. The mortality and major morbidity rates were 0%. The visual function outcome was satisfactory, with the overall visual status improving in all seven patients in whom this symptom was present preoperatively. The ultrasonic bone curette makes the unroofing of the optic canal safer and easier, possibly improving the visual outcome of patients undergoing surgery for parasellar tumors.

✓ The pathophysiology of syringomyelia is still not well understood. Current prevailing theories involve the assumption that cerebrospinal fluid (CSF) flows into the syrinx from the subarachnoid space through the perivascular space of Virchow—Robin. Reported here is the case of a patient with syringomyelia in which this course is clearly contradicted. This patient with a holocord syrinx associated with adhesive arachnoiditis was treated 3 years previously with insertion of a subarachnoid—peritoneal shunt and had recently experienced worsening myelopathy. On surgical exploration, the shunt system was functioning normally. The medium-pressure shunt valve was replaced with an adjustable valve with a higher closing pressure setting, thus increasing the CSF pressure in the subarachnoid space. Contrary to prevailing theories, this procedure markedly reduced the size of the syrinx. This case provides direct evidence that the syrinx size is inversely related to subarachnoid CSF pressure and supports the hypothesis that the pressure gradient across the spinal cord parenchyma is the force that generates syringes in syringomyelia.

This study is an attempt to clarify surgical decision-making on cerebral cavernous malformations based on the data available in the literature. Using a mathematical model, we calculated the morbidity-free survival curves of the patients harboring cerebral cavernous malformations. Using these survival curves, we calculated the morbidity-free life expectancies of the patients at certain age undergoing either natural course or surgery. For superficially located lesions, permissible surgical risks were very small ranging from 0.4 to 2.8 percent of combined morbidity and mortality. The surgical gain of morbidity free life expectancy was also very small (0.0-1.1 years) irrespective of patient's age or eloquence of the location. For deep lesions, the permissible risk of surgery was very large, ranging from 64.1% for a 20-year-old and 31.4% for a 60-year-old patient. The gain of morbidity-free life expectancy was also large for younger patients (17-25 years for 20-year-old patients), but this gain rapidly decreased as the patient's age grew older, becoming 1.1 to 3.1 years for 60-year-old patients. Surgery seems to be justified for younger patients with deep lesions. There seems to be little indication for surgery of superficial lesions as far as the risk of bleeding is concerned.

In various types of syringomyelia, the pathogenesis seems to be related to some derangement of cerebrospinal fluid (CSF) dynamics. In this report, we describe our mathematical model of CSF dynamics in the spine, and show how this model can effectively explain the pathogenesis of various types of syringomyelia. We constructed an electric circuit model of the CSF dynamics in the spine based on techniques of computational fluid mechanics. Using this model, we examined the behavior of this system to a step increase of pressure applied on the cranial side. We then simulated various conditions such as Chiari malformation, stenosis of the central canal, and adhesive arachnoiditis. The wall pressure across the central canal was sensitive to a decrease in capacitance at the cisterna magna. When the capacitance at the cisterna magna was decreased, as in Chiari I malformation, there was a marked increase of wall pressure, peaking at the low cervical segment of the spinal cord. If stenosis of the central canal was present, the wall pressure increased immediately proximal to the stenotic site. Blocking the subarachnoid CSF flow caused increased wall pressure of the central canal distal to the blocked site. Our mathematical model of CSF dynamics could explain the pathogenesis of various types of syringomyelia. It can serve as a useful working hypothesis in our future study of this disease.

A noninvasive test for shunt function would be beneficial in the management of patients with CSF shunting. We present our method to diagnose shunt function using MRI. We performed two experiments. In the first we simultaneously performed MRI of two tubes, one with water flowing inside at various flow speeds and the other with static water inside, and compared the signal intensity inside each lumen. In the second we took four MR images of the actual shunt tubes in three patients at different states of shunt function, each having a tube containing static water pasted side by side with the actual subcutaneous shunt tube. In the first experiment we could detect the enhancement effect of slow flow. The minimal detectable flow speed using this method was {approx}1.7 ml/h. The results obtained in actual patients matched the clinical status of the shunt function. This method would be useful as a qualitative test for shunt function. 19 refs., 4 figs., 1 tab.

✓ A case of a ruptured fusiform aneurysm of the posterior cerebral artery is reported. The aneurysm was excised and end-to-end anastomosis was carried out between the two ends of the posterior cerebral artery. There is no previous report of a posterior cerebral artery aneurysm treated with this technique. The pertinent literature is reviewed and the significance of this technique in the treatment of unclippable cerebral aneurysms is discussed.

Ten cases of posterior cerebral artery (PCA) aneurysm are presented. There were 13 aneurysms in the 10 patients: 6 saccular, 5 fusiform, 1 broad-based, and 1 giant fusiform serpentine aneurysm. Eight patients underwent operation: clipping for 2 saccular aneurysms, trapping for 1 saccular and 3 fusiform aneurysms, and coating for 2 fusiform or broad-based aneurysms. Microsurgical cerebral revascularization techniques were attempted in 2 cases: after a fusiform aneurysm had been excised, end-to-end anastomosis of the residual two ends of the PCA was performed and, after a giant serpentine aneurysm had been trapped, the superficial temporal artery was anastomosed transcortically to the distal PCA. Two patients died before operation because of rebleeding and vasospasm. Postoperative neurological deficits include contralateral hemiparesis, homonymous hemianopsia, hemihypesthesia, and ipsilateral 3rd nerve palsy. Our results suggest that, despite the good collateral circulation of the PCA, some ischemic events may occur after trapping procedures and that cerebral revascularization techniques may have some benefit in the treatment of unclippable aneurysms in this region.

Cerebrospinal fluid leakage is a relatively rare complication after an anterior cervical spine operation1, except when the diagnosis includes ossification of the posterior longitudinal ligament. In patients with such a diagnosis, the dura is usually thin because of long-standing compression by the ossification; furthermore, there may be a dural defect or dural ossification2. Although cerebrospinal fluid leakage may cause wound dehiscence and subsequent infection, it has not been recognized as a cause of airway problems, to our knowledge. In this report, we present two cases of postoperative cerebrospinal fluid leakage that caused acute airway obstruction, requiring emergency treatment.The patients were informed that data concerning the cases could be submitted for publication. Case 1. A sixty-one-year-old man presented with mild sensory abnormalities of the upper extremities and a gait disturbance. Cervical spine radiographs, computed tomography scans, and magnetic resonance images showed segmental ossification of the posterior longitudinal ligament compressing the spinal cord at the C3-C4, C4-C5, and C5-C6 levels. The patient underwent anterior cervical decompression with inter-body fixation with cages. During this procedure, a dural tear with cerebrospinal fluid leakage occurred at the C5-C6 level and was repaired with a muscle patch and fibrin glue. The evening of the next day, the patient showed signs of upper airway obstruction with rapidly progressive dyspnea. A cervical spine radiograph demonstrated enlargement of the prevertebral soft-tissue shadow (Fig. 1). Computed tomography of the cervical spine showed a large prevertebral mass with low density. After a failed attempt at fiberscopic intubation, we performed an emergency tracheostomy, and the patient underwent surgical exploration of the wound. When we opened the sutures in the platysma, cerebrospinal fluid flowed briskly out from the prevertebral space, decreasing the tension of the wound. We …

Single unit activity of CA1 and CA3 neurons in the hippocampus was recorded in rats 1, 2, or 3 days after 10 minutes of transient cerebral ischemia induced by the clamping of both carotid arteries combined with hypotension. In addition, paired pulse inhibition/facilitation of the CA1 population spike was examined on Day 2 using two successive stimuli of the contralateral CA3 region delivered at various intervals. On Day 1, the mean +/- SEM firing rate in the CA1 region was 0.91 +/- 0.42/sec (n = 5), which was not significantly different from the control value of 0.98 +/- 0.26/sec (n = 5). Firing rate increased on Days 2 and 3 to 3.96 +/- 0.69/sec (n = 5), and 6.49 +/- 0.89/sec (n = 5), respectively. In the CA3 region, the mean +/- SEM firing rate of 1.18 +/- 0.27/sec in the five control rats sharply dropped to 0.14 +/- 0.11/sec in the five Day 1 rats and gradually increased to 0.45 +/- 0.11/sec in the five Day 3 rats. Histologic examination of these rats revealed ischemic changes restricted to CA1 neurons on Days 2 and 3. The paired-pulse experiment showed no significant difference between six control and six Day 2 rats in the inhibition of the second population spike with interstimulus intervals of less than 400 msec. At interstimulus intervals of greater than 500 msec there was facilitation of the second spike, which lasted 5 seconds in Day 2 rats. This facilitation was not observed in control rats. Because CA3 neurons constitute the main input to CA1 pyramidal cells, decreased activity of CA3 neurons indicates less excitatory input to CA1 neurons.(ABSTRACT TRUNCATED AT 250 WORDS)