Dural Arteriovenous Fistula Treated with Transvenous Embolization via the Upper Limb Cutaneous Vein.

Objective: In recent years, the transradial artery approach has gained prominence and is increasingly employed in neurovascular angiography and therapy due to its safety, reduced complications, and minimal invasiveness. While various venous approaches, including the conventional transfemoral vein approach, exist for procedures such as transvenous embolization, recent reports have highlighted methods involving upper extremity cutaneous veins. However, the practicality and efficacy of these approaches remain unclear. Case Presentations: This study presents our experience with three cases of dural arteriovenous fistulas, where transvenous embolization was performed via upper limb cutaneous veins. In all instances, the arteriovenous approach was successfully executed using a single upper extremity, leading to the successful completion of treatment. Conclusion: This technique demonstrates significant advantages, not only in terms of its minimal invasiveness but also due to its simplicity and safety. Anticipating broader acceptance in the future, this approach offers a promising avenue for further exploration in neurovascular interventions.

Correlation of active contact location with weight gain after subthalamic nucleus deep brain stimulation: a case series.

BACKGROUND: Weight gain (WG) is a frequently reported side effect of subthalamic deep brain stimulation; however, the underlying mechanisms remain unclear. The active contact locations influence the clinical outcomes of subthalamic deep brain stimulation, but it is unclear whether WG is directly associated with the active contact locations. We aimed to determine whether WG is associated with the subthalamic deep brain stimulation active contact locations. METHODS: We enrolled 14 patients with Parkinson's disease who underwent bilateral subthalamic deep brain stimulation between 2013 and 2019. Bodyweight and body mass index were measured before and one year following the surgery. The Lead-DBS Matlab toolbox was used to determine the active contact locations based on magnetic resonance imaging and computed tomography. We also created sweet spot maps for WG using voxel-wise statistics, based on volume of tissue activation and the WG of each patient. Fluorodeoxyglucose-positron emission tomography data were also acquired before and one year following surgery, and statistical parametric mapping was used to evaluate changes in brain metabolism. We examined which brain regions' metabolism fluctuation significantly correlated with increased body mass index scores and positron emission tomography data. RESULTS: One year after surgery, the body mass index increase was 2.03 kg/m2. The sweet spots for WG were bilateral, mainly located dorsally outside of the subthalamic nucleus (STN). Furthermore, WG was correlated with increased metabolism in the left limbic and associative regions, including the middle temporal gyrus, inferior frontal gyrus, and orbital gyrus. CONCLUSIONS: Although the mechanisms underlying WG following subthalamic deep brain stimulation are possibly multifactorial, our findings suggest that dorsal stimulation outside of STN may lead to WG. The metabolic changes in limbic and associative cortical regions after STN-DBS may also be one of the mechanisms underlying WG. Further studies are warranted to confirm whether dorsal stimulation outside of STN changes the activities of these cortical regions.

Chronic deep brain stimulation reduces cortical ß-γ phase amplitude-coupling in patients with Parkinson's disease.

We compared ß-γ phase amplitude coupling (PAC) before and one year after chronic deep brain stimulation (DBS) in patients with Parkinson's disease using EEG and observed significant post-operative reduction of PAC values. Our findings suggest that the reduction in PAC due to DBS can be observed after chronic stimulation, which is not a transient phenomenon just after the start of DBS.

A Case of Ruptured Cerebral Aneurysm with Asymmetric Fusion of Basilar Apex.

Objective: We report a case of a ruptured cerebral aneurysm in which a bifurcation pattern at the tip of the basilar artery was asymmetric fusion type and the superior cerebellar artery (SCA) branched from the posterior cerebral artery (PCA) on the caudal fusion type side. Case Presentation: A 45-year-old woman presented with a subarachnoid hemorrhage with a headache. Cerebral angiography revealed that the right SCA diverged from the PCA and a small cerebral aneurysm had developed at this site. This cerebral aneurysm was successfully treated by coil embolization. Conclusion: There have been no previous reports on cerebral aneurysms at the site of this normal variation.

Vascular Smooth Muscle Cell Derived from IPS Cell of Moyamoya Disease - Comparative Characterization with Endothelial Cell Transcriptome.

BACKGROUND: Moyamoya disease (MMD) is an occlusive cerebrovascular disease, causing stroke in children and young adults with unknown etiology. The fundamental pathology is fibrocellular intimal thickening of cerebral arteries, in which vascular smooth muscle cells (VSMCs) are observed as one of the major cell types. Although the characteristics of circulating smooth muscle progenitor cells have been previously reported, the VSMCs are poorly characterized in MMD. We aimed to characterize VSMCs in MMD using induced pluripotent stem cell (iPSC)-technology. METHODS: We differentiated VSMCs from neural crest stem cells (NCSCs) using peripheral blood mononuclear cell-derived iPSCs and compared biological and transcriptome features under naïve culture conditions between three independent healthy control (HC) subjects and three MMD patients. VSMC transcriptome profiles were also compared to those of endothelial cells (ECs) differentiated from the same iPSCs. RESULTS: Homogeneous spindle-shaped cells differentiated from iPSCs exhibited smooth muscle cell marker expressions, including α-smooth muscle actin (αSMA, 82.3 ± 6.7% and 81.0 ± 6.7%); calponin (91.3 ± 2.1% and 90.9 ± 1.3%); myosin heavy chain-11 (MYH11, 96.9 ± 0.7% and 97.1 ± 0.3%) without significance of differences between the two groups. Real-time PCR showed few PECAM1 and CD34 gene expressions in both groups, indicating features of differentiated VSMCs. There were no significant differences in cellular proliferation (p = 0.45), migration (p = 0.60), and contractile abilities (p = 0.96) between the two groups. Transcriptome analysis demonstrated similar gene expression profiles of VSMCs in HC subjects and MMD patients with six differentially expressed genes (DEGs); while ECs showed a distinct transcriptome profile in MMD patients with 120 DEGs. The Wnt-signaling pathway was a significant pathway in VSMCs. CONCLUSIONS: This is the first study that established VSMCs from NCSCs using MMD patient-derived iPSCs and demonstrated similar biological function and transcriptome profile of iPSC-derived VMSCs in MMD patients and HC subjects under naïve single culture condition. Comparative transcriptome features between iPSC-derived VSMCs and ECs, displaying distinct transcriptome in the ECs, suggested that pathological traits can be driven by naïve ECs predominantly and VSMCs may require specific environmental factors in MMD, which provides novel insight into the pathophysiology of MMD. Our iPSC derived VSMC model can contribute to further investigations of diagnostic and therapeutic target of MMD in addition to the current iPSC derived EC model.

Spinal rosette-forming glioneuronal tumor: A case report.

RATIONALE: Rosette-forming glioneuronal tumor (RGNT) is a rare tumor which has been first reported as the fourth ventricle tumor by Komori et al and is classified as a distinct clinicopathological entity by the WHO Classification of Tumors of the Central Nervous System as in 2007. Although RGNTs were reported to occur in both supratentorial and inflatentorial sites, only 4 case reports of spinal RGNT have been demonstrated. PATIENT CONCERNS: A 37-year-old female presenting with slowly progressing right-sided clumsiness. Cervical magnetic resonance imaging revealed a spinal intramedullary tumor between the C2 and C5 levels. DIAGNOSES: Pathological analysis showed unique biphasic cellular architecture consisting of perivascular pseudorosettes dominantly with few neurocytic rosettes and diffuse astrocytoma component. The tumor cells composed of perivascular pseudorosettes showed positivity for both synaptophysin and glial markers such as GFAP and Olig2. Therefore, the diagnosis of RGNT was made. INTERVENTIONS: Gross total resection of the tumor was achieved. No adjuvant chemotherapy nor radiotherapy was conducted after operation. OUTCOMES: At 2 years after the operation, no recurrence was observed. LESSONS: Although RGNT arising from the spinal cord is extremely rare, we need to consider the tumor as a differential diagnosis for intramedullary spinal cord tumors.

Investigation of the Neuropathic Pain Caused by Syringomyelia Associated with Chiari I Malformation.

Study Design: Retrospective cohort study. Purpose: To investigate the correlation between the syrinx morphology and neuropathic pain caused by syringomyelia associated with Chiari I malformation. Overview of Literature: Neuropathic pain caused by syringomyelia is refractory and markedly impairs the patient. Methods: We examined 24 patients with neuropathic pain caused by syringomyelia associated with Chiari I malformation. We statistically analyzed the illness duration and age at surgery between patients with and without neuropathic pain. Additionally, we classified the morphology of the syringes into deviated (D), enlarged (E), central (C), and bulkhead (B) types using T2-weighted axial imaging. Moreover, we investigated the correlation between syrinx morphology and neuropathic pain. A Mann-Whitney U-test was performed to compare between the presence or absence of neuropathic pain and the presence or absence of type D syringes. Results: The median age at surgery was 27.5 years, and the median illness duration was 24 months. Among the 24 patients, 11 had preoperative neuropathic pain, one of which was free of neuropathic pain during the final follow-up period. Among patients with neuropathic pain, the syringes' preoperative morphology was type D in nine patients and types E and C in one patient each. No patient exhibited type B morphology. Among patients without neuropathic pain, the preoperative morphology of the syringes was type D in three patients, type E in seven patients, and types C and B in two patients each. For types D and E, a correlation between neuropathic pain and syrinx morphology was observed. Moreover, type D was associated with significant neuropathic pain in both preoperative and postoperative states. Conclusions: This study showed a correlation between the morphological features of the syringes and the occurrence of neuropathic pain in patients with syringomyelia associated with Chiari I malformation.

Estimation of the number of feeding arteries of spinal arteriovenous malformations by using three-dimensional digital subtraction angiography.

PURPOSE: Spinal angiography is the gold standard for evaluation or diagnosis of spinal arteriovenous malformations (AVMs). However, some feeding arteries might be overlooked when multiple feeders exist. This study aimed to retrospectively review cases of spinal intra-dural AVMs, which were identified by three-dimensional digital subtraction angiography (3D-DSA), and attempted to estimate the number of feeding arteries. METHODS: We retrospectively reviewed patients with spinal intra-dural AVMs who underwent 3D-DSA at Hokkaido University Hospital from January 2005 to December 2016. We selected 9 patients in whom we could obtain data of multi-planar reconstruction of 3D-DSA. We measured the computed tomography (CT) values of feeding arteries and draining veins. The CT values represented the averages of maximum CT values of 5 continuous axial slices. The ratio of the CT value of feeders to that of drainers (F/D ratio) was calculated. The correlation between the F/D ratio and the number of feeders was examined with Pearson's correlation coefficient. RESULTS: The average number of feeders was 2.3 (1-4), and the number of feeders was significantly positively correlated with the F/D ratio (r = 0.855, P = .003). CONCLUSIONS: We conclude that the number of feeding arteries of spinal intra-dural AVMs can be estimated by using the F/D ratio obtained from 3D-DSA. These slides can be retrieved under Electronic Supplementary Material.

Circulating miRNome profiling in Moyamoya disease-discordant monozygotic twins and endothelial microRNA expression analysis using iPS cell line.

BACKGROUND: Moyamoya disease (MMD) is characterized by progressive stenosis of intracranial arteries in the circle of Willis with unknown etiology even after the identification of a Moyamoya susceptible gene, RNF213. Recently, differences in epigenetic regulations have been investigated by a case-control study in MMD. Here, we employed a disease discordant monozygotic twin-based study design to unmask potential confounders. METHODS: Circulating genome-wide microRNA (miRNome) profiling was performed in MMD-discordant monozygotic twins, non-twin-MMD patients, and non-MMD healthy volunteers by microarray followed by qPCRvalidation, using blood samples. Differential plasma-microRNAs were further quantified in endothelial cells differentiated from iPS cell lines (iPSECs) derived from another independent non-twin cohort. Lastly, their target gene expression in the iPSECs was analyzed. RESULTS: Microarray detected 309 plasma-microRNAs in MMD-discordant monozygotic twins that were also detected in the non-twin cohort. Principal component analysis of the plasma-microRNA expression level demonstrated distinct 2 groups separated by MMD and healthy control in the twin- and non-twin cohorts. Of these, differential upregulations of hsa-miR-6722-3p/- 328-3p were validated in the plasma of MMD (absolute log2 expression fold change (logFC) > 0.26 for the twin cohort; absolute logFC > 0.26, p < 0.05, and q < 0.15 for the non-twin cohort). In MMD derived iPSECs, hsa-miR-6722-3p/- 328-3p showed a trend of up-regulation with a 3.0- or higher expression fold change. Bioinformatics analysis revealed that 41 target genes of miR-6722-3p/- 328-3p were significantly down-regulated in MMD derived iPSECs and were involved in STAT3, IGF-1-, and PTEN-signaling, suggesting a potential microRNA-gene expression interaction between circulating plasma and endothelial cells. CONCLUSIONS: Our MMD-discordant monozygotic twin-based study confirmed a novel circulating microRNA signature in MMD as a potential diagnostic biomarker minimally confounded by genetic heterogeneity. The novel circulating microRNA signature can contribute for the future functional microRNA analysis to find new diagnostic and therapeutic target of MMD.

Myelocystocele Mimicking Myelomeningocele: A Case Report and Review of the Literature.

BACKGROUND: Myelocystoceles, which are classified as closed neural tube defects, are usually covered by skin and rarely complicated by hydrocephalus. We encountered an unusual case of a terminal myelocystocele with hydrocephalus with clinical characteristics of a myelomeningocele. CASE DESCRIPTION: Severe hydrocephalus and a lumbosacral lesion were detected in the fetus of a gravid 34-year-old woman. Cesarean section was performed at 37 weeks. The neonate presented with a lumbosacral mass with a partial skin defect. As myelomeningocele was suspected, the neonate underwent surgery on the day of birth. The intraoperative findings pointed to a myelocystocele rather than a myelomeningocele. After insertion of a ventriculoperitoneal shunt, the neonate was discharged without any neurologic deficits. CONCLUSIONS: Presence of skin abnormalities, hydrocephalus, and lumbosacral mass strongly suggests a diagnosis of myelomeningocele. However, such cases should be differentiated from myelocystocele, especially when associated with severe hydrocephalus.

Intraoperative real-time identification of abnormal vessels within the bright field by superselective arterial injection of saline and its slow-motion recording using a high frame rate digital camera during surgical treatment of spinal arteriovenous shunts: technical note.

The authors describe a novel method of observing blood flow in abnormal vessels with slow-motion video during surgical treatment of spinal arteriovenous shunts. The method is based on the use of superselective angiography with saline for visualizing abnormal vessels in bright field and commercially available high frame rate digital camera for recording slow-motion video.

[Utility of Intraoperative Catheter Myelography during Intrathecal Baclofen Pump Implantation:Report of 2 Cases].

We report two patients in whom the intrathecal baclofen(ITB)catheter was located in the subdural space, although we had confirmed good outflow of spinal fluid from the spinal catheter. Patient 1 was a woman in her 30s with spastic quadriplegia due to subarachnoid hemorrhage. An ITB pump was implanted, and a good outflow of spinal fluid from the spinal catheter was observed during the surgery. Postoperatively, her spasticity did not improve. Catheter myelography revealed that the spinal catheter was located in the subdural space. Using intraoperative catheter myelography, we corrected the position of the catheter. Patient 2 was a man in his 20s diagnosed with adrenoleukodystrophy. An ITB therapy was performed to improve his spastic gait. Intraoperative catheter myelography showed that the spinal catheter was located in the subdural space, although there was good outflow of spinal fluid from the catheter. Our experience suggests that the outflow of spinal fluid alone should not be used to determine the location of the spinal catheter. Intraoperative catheter myelography is useful for the correct placement of the spinal catheter in the subarachnoid space.

Feasibility and Efficiency of Human Bone Marrow Stromal Cell Culture with Allogeneic Platelet Lysate-Supplementation for Cell Therapy against Stroke.

Currently, there is increasing interest in human bone marrow stromal cells (hBMSCs) as regeneration therapy against cerebral stroke. The aim of the present study was to evaluate the feasibility and validity of hBMSC cultures with allogeneic platelet lysates (PLs). Platelet concentrates (PC) were harvested from healthy volunteers and made into single donor-derived PL (sPL). The PL mixtures (mPL) were made from three different sPL. Some growth factors and platelet cell surface antigens were detected by enzyme-linked immunosorbent assay (ELISA). The hBMSCs cultured with 10% PL were analyzed for their proliferative potential, surface markers, and karyotypes. The cells were incubated with superparamagnetic iron oxide (SPIO) agents and injected into a pig brain. MRI and histological analysis were performed. Consequently, nine lots of sPL and three mPL were prepared. ELISA analysis showed that PL contained adequate growth factors and a particle of platelet surface antigens. Cell proliferation capacity of PLs was equivalent to or higher than that of fetal calf serum (FCS). No contradiction in cell surface markers and no chromosomal aberrations were found. The MRI detected the distribution of SPIO-labeled hBMSCs in the pig brain. In summary, the hBMSCs cultured with allogeneic PL are suitable for cell therapy against stroke.

Cellular Functions and Gene and Protein Expression Profiles in Endothelial Cells Derived from Moyamoya Disease-Specific iPS Cells.

BACKGROUND AND PURPOSE: Moyamoya disease (MMD) is a slow, progressive steno-occlusive disease, arising in the terminal portions of the cerebral internal carotid artery. However, the functions and characteristics of the endothelial cells (ECs) in MMD are unknown. We analyzed these features using induced pluripotent stem cell (iPSC)-derived ECs. METHODS: iPSC lines were established from the peripheral blood of three patients with MMD carrying the variant RNF213 R4810K, and three healthy persons used as controls. After the endothelial differentiation of iPSCs, CD31+CD144+ cells were purified as ECs using a cell sorter. We analyzed their proliferation, angiogenesis, and responses to some angiogenic factors, namely VEGF, bFGF, TGF-ß, and BMP4. The ECs were also analyzed using DNA microarray and proteomics to perform comprehensive gene and protein expression analysis. RESULTS: Angiogenesis was significantly impaired in MMD regardless of the presence of any angiogenic factor. On the contrary, endothelial proliferation was not significant between control- and MMD-derived cells. Regarding DNA microarray, pathway analysis illustrated that extracellular matrix (ECM) receptor-related genes, including integrin ß3, were significantly downregulated in MMD. Proteomic analysis revealed that cytoskeleton-related proteins were downregulated and splicing regulation-related proteins were upregulated in MMD. CONCLUSIONS: Downregulation of ECM receptor-related genes may be associated with impaired angiogenic activity in ECs derived from iPSCs from patients with MMD. Upregulation of splicing regulation-related proteins implied differences in splicing patterns between control and MMD ECs.

Development of a nonintermediate-incision ventriculoperitoneal shunt procedure using a nasogastric feeding tube for infant patients with hydrocephalus: technical note.

Intermediate incisions are considered necessary to pass a catheter tube from the head to the abdomen in ventriculo-peritoneal (VP) shunting via a frontal bur hole. However, an intermediate incision can sometimes become dehiscent, resulting in CSF leakage or infection of the shunt system in the early period after shunt implantation, particularly in infant patients. In this article, the authors describe a novel method of VP shunt insertion that does not require an intermediate incision. This nonintermediate-incision VP shunt procedure was performed in 3 infant patients with hydrocephalus and was not associated with any complications. This method can eliminate the intermediate incision, which is a disadvantage of VP shunt insertion via a frontal bur hole.

Short-, middle- and long-term safety of superparamagnetic iron oxide-labeled allogeneic bone marrow stromal cell transplantation in rat model of lacunar infarction.

Recently, both basic and clinical studies demonstrated that bone marrow stromal cell (BMSC) transplantation therapy can promote functional recovery of patients with CNS disorders. A non-invasive method for cell tracking using MRI and superparamagnetic iron oxide (SPIO)-based labeling agents has been applied to elucidate the behavior of transplanted cells. However, the long-term safety of SPIO-labeled BMSCs still remains unclear. The aim of this study was to investigate the short-, middle- and long-term safety of the SPIO-labeled allogeneic BMSC transplantation. For this purpose, BMSCs were isolated from transgenic rats expressing green fluorescent protein (GFP) and were labeled with SPIO. The Na/K ATPase pump inhibitor ouabain or vehicle was stereotactically injected into the right striatum of wild-type rats to induce a lacunar lesion (n = 22). Seven days after the insult, either BMSCs or SPIO solution were stereotactically injected into the left striatum. A 7.0-Tesla MRI was performed to serially monitor the behavior of BMSCs in the host brain. The animals were sacrificed after 7 days (n = 7), 6 weeks (n = 6) or 10 months (n = 9) after the transplantation. MRI demonstrated that BMSCs migrated to the damage area through the corpus callosum. Histological analysis showed that activated microglia were present around the bolus of donor cells 7 days after the allogeneic cell transplantation, although an immunosuppressive drug was administered. The SPIO-labeled BMSCs resided and started to proliferate around the route of the cell transplantation. Within 6 weeks, large numbers of SPIO-labeled BMSCs reached the lacunar infarction area from the transplantation region through the corpus callosum. Some SPIO nanoparticles were phagocytized by microglia. After 10 months, the number of SPIO-positive cells was lower compared with the 7-day and 6-week groups. There was no tumorigenesis or severe injury observed in any of the animals. These findings suggest that BMSCs are safe after cell transplantation for the treatment of stroke.

[A case of symptomatic pituitary metastases from renal cell carcinoma].

Symptomatic metastases to the pituitary from renal cell carcinoma are rare. We present a case of pituitary metastases from renal cell carcinoma showing panhypopituitarism. A 50-year-old man who had renal cell carcinoma with distant metastases in skin, bone and lymph nodes was referred to our department. Clinically he showed severe cognitive function disorder. Endocrinological evaluation revealed central adrenal and gonadal insufficiencies. Brain magnetic resonance imaging demonstrated a hemorrhagic mass in left frontal lobe and a sellar mass with supra sellar cistern extension. After hormonal replacement and surgical removal of the frontal tumor, he immediately recovered from his cognitive function disorder. Subsequently, whole brain radiotherapy for metastatic pituitary tumor was performed. At present, he is being treated with molecular targeting drugs for other distant metastases and he presents no neurological deficit. Palliative therapy for CNS metastases from renal cell carcinoma may result in better quality of life for patients with advanced stage of renal cell carcinoma.

[The repair of traumatic cerebrospinal fluid leak using temporal loose areolar connective tissue insertion into the frontal sinus and pericranial flap covering: a case report].

We report a case of cerebrospinal fluid (CSF) leak repair using loose areolar connective tissue insertion into the frontal sinus and pericranial flap covering. A 61-years-old man suffered from skull fracture including frontal sinus fracture in violence inflicted by others. Fifty days later, he presented rhinorrhea and pneumocephalus caused by a bone defect site of the frontal sinus and anterior skull base. We performed CSF leak repair with insertion of pedunculated loose areolar connective tissue into his frontal sinus, covering the leak point using pericranial flap. In general, frontal sinus obliteration has been accomplished with autologous grafts such as fat, muscle, or bone. These avascular grafts carry an increased risk of resorption and infection. The use of loose areolar tissue insertion into the frontal sinus was able to increase stability of the construct and caused no cosmetic troubles in our short follow up period. The combined use of these two autologous materials may be useful for repair of CSF leak from an anterior skull base fracture.

[Schwannoma developing in the psoas major muscle: a case report].

Schwannoma can occur wherever peripheral nerve Schwann cells are found. However, retroperitoneal schwannoma is extremely rare in that only 16 cases have been reported, including that of the present patient. A 51-year-old male complained of chronic lower back pain and paresthesia in the lower left region. Lower back pain increased with leftward bending. Magnetic resonance imaging (MRI) revealed a neoplastic lesion about 6 cm in diameter in the left psoas major muscle, and the lesion was in contact with the L4 and L5 vertebral bodies. The tumor did not continue to the lumbar foramen. The symptom had become disabling, therefore tumor removal was performed using Wiltse's approach. From intraoperative findings, the origin of the tumor was suspected to be the L4 nerve root. The ventral surface of the tumor could not be observed with this posterior approach. Lumbar plexus might adhere closely to the ventral surface of the tumor, therefore the capsule of the tumor was left to avoid neurological deterioration. Schwannoma was diagnosed by pathological analysis, and no malignancy was evident. After the operation, symptoms were completely relieved, and the residual capsule of the tumor diminished in size on MRI after 12 months. The posterior Wiltse's approach can be useful to treat mass lesions in the psoas major muscle. The 16 reported cases of retroperitoneal schwannoma, including that of the present patient, are reviewed.

[Ketamine treatment for severe neuropathic pain with cervical spondylotic myelopathy. A case report].

This 60-year-old man with cervical spondylosis experienced bilateral arm pain and weakness. After anterior cervical fusion and posterior decompression at a local hospital his symptoms worsened and he was admitted to our hospital. On admission he manifested bilateral motor weakness, neuropathic pain, and numbness below the C5 level. Radiological findings showed spinal cord compression at the C4 to C7 level. He again underwent posterior decompression and anterior fusion. Although his paresis was improved, his severe neuropathic pain and numbness persisted. Because treatment with NSAIDs, clonazepam, and gabapentin failed to control his symptoms we administered ketamine (NMDA receptor antagonist) because his symptoms were alleviated upon ketamine test challenge. His severe symptoms improved and there were no complications. However, upon cessation of ketamine treatment they reappeared. Therefore, we continued daily ketamine treatment for 6 months, after which we changed to codeine phosphate. His symptoms were controlled without any complications. Ketamine is useful for the control of severe neuropathic pain, however, as long-term ketamine administration is inadvisable, we suggest that treatment be tailored to each patient's particular clinical status.