Naoaki Fujisawa

Analysis of risk factors for chronic subdural haematoma recurrence after burr hole surgery: optimal management of patients on antiplatelet therapy.

Abstract 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.

Degenerative spondylolisthesis does not affect the outcome of unilateral laminotomy with bilateral decompression in patients with lumbar stenosis.

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

Microsurgical posterolateral transmuscular approach for lumbar foraminal stenosis.

Study Design Retrospective review of 39 consecutive patients who underwent surgery for lumbar foraminal stenosis from 2004 to 2009. Objective 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. Summary of Background Data 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. Methods 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 &khgr;2 method. Results 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. Conclusions Posterolateral transmuscular approach with microsurgical foraminotomy provided excellent surgical results. Coronal thin-sliced MRI can be useful for diagnosis of this disease.

Beneficial Effect of Selective Intra-arterial Infusion of Fasudil Hydrochloride as a Treatment of Symptomatic Vasospasm Following SAH

INTRODUCTION 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. MATERIAL AND METHODS 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. RESULT 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. DISCUSSION 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.

Syringomyelia associated with arachnoid septum at the craniovertebral junction, contradicting the currently prevailing theory of syringomyelia formation

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.

Usefulness of repetitive intraoperative indocyanine green-based videoangiography to confirm complete obliteration of micro-arteriovenous malformations.

Background: It is difficult to intraoperatively confirm the total disappearance of arteriovenous (AV) shunts during surgery for microarteriovenous malformations (micro-AVMs), especially when the nidus is extremely small or diffuse on preoperative angiography. Although intraoperative angiography is effective for evaluating residual shunts, procedure-related risks raise important concerns. The purpose of this study was to assess the usefulness of intraoperative indocyanine green-based videoangiography (ICG–VA) to determine complete disappearance of micro-AVMs during surgery. Methods: We retrospectively analyzed eight patients with ruptured micro-AVMs who were treated using craniotomy with ICG–VA at our institution. Results: Two patients underwent emergency partial evacuation of hematoma and external decompression before the diagnostic angiography. While three patients had a nidus smaller than 1 cm, five patients had only early draining veins without an appreciable nidus. The draining veins were superficial in six cases and deep in two cases. The average interval from onset to surgery was 33 days (range, 2–57). ICG–VA was repetitively conducted until disappearance of the AV shunt was confirmed. No residual AV shunt was observed on postoperative radiological examinations. In all cases, the diagnosis of AVM was confirmed from the results of postoperative pathological examination. Conclusions: ICG–VA could detect early draining veins more clearly in situ than diagnostic angiography. Although it is not as effective for visualizing lesions with deep draining veins, repetitive ICG–VA was safe and effective for confirming the disappearance of AV shunts with superficial drainage.

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids with a Significant Elevation of β-2 Microglobulin Levels

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a relapsing-remitting disorder for which steroid administration is a key to control the progression. CLIPPERS can exhibit radiological features similar to malignant lymphoma, whose diagnosis is confounded by prior steroid administration. We report a case of CLIPPERS accompanied by abnormal elevation of β-2 microglobulin in the cerebrospinal fluid (CSF). A 62-year-old man started to experience numbness in all fingers of his left hand one year ago, which gradually extended to his body trunk and legs on both sides. Magnetic resonance imaging demonstrated numerous small enhancing spots scattered in his brain and spinal cord. CSF levels of β-2 microglobulin were elevated; although this often indicates central nervous system involvement in leukemia and lymphoma, the lesions were diagnosed as CLIPPERS based on the pathological findings from a biopsy specimen. We emphasize the importance of biopsy to differentiate between CLIPPERS and malignant lymphoma because the temporary radiological response to steroid might be the same in both diseases but the treatment strategies regarding the use of steroid are quite different.

Hemichorea-hemiballismus caused by postoperative hyperperfusion after clipping of a giant unruptured middle cerebral artery aneurysm.

Background: Movement disorders after the clipping for an unruptured giant aneurysm are rare. The information on the pathogenesis and treatment options for this condition is largely unknown. Case Description: An 82-year-old female with no neurological deficits underwent a clipping for a giant middle cerebral artery (MCA) aneurysm. Immediately after surgery, she presented with hemichorea–hemiballismus (HC–HB) on the left side. Postoperative angiograms and single-photon emission computed tomography demonstrated the hyperperfusion in the right frontal cortex and the decreased perfusion in the basal ganglia, indicating that the abrupt hemodynamic changes due to the obliteration of the giant aneurysm caused the dysfunction of the frontal cortical and subcortical pathway and the basal ganglia. Administration of tiapride hydrochloride was dramatically effective in controlling the HC–HB until the hyperperfusion resolved. Single-photon emission computed tomography obtained 8 weeks after surgery revealed that the cerebral blood flow had been normalized in the right frontal cortex. The relative hypoperfusion of the right basal ganglia was also resolved. Then tiapride hydrochloride was discontinued without a relapse of HC–HB. Conclusion: This case appears consistent with the theory that the connecting fibers responsible for the development of HC–HB are also located in the frontal lobe. The treatment of giant aneurysms involving the M1 portion can cause abrupt hemodynamic changes in both frontal cortex and the basal ganglia, which can potentially induce postoperative movement disorders.