Joon Cho

Reoperation for persistent or recurrent hemifacial spasm after microvascular decompression

OBJECTIVE:The objective of this study was to investigate the outcome of reoperation for persistent or recurrent hemifacial spasm (HFS) after microvascular decompression (MVD). METHODS:Repeat MVD was performed on 13 patients with an HFS between June 1994 and May 2004. Patients who had compressing offending vessels identified on postoperative (prerevision) three-dimensional short-range magnetic resonance angiography were selected for repeat MVD. RESULTS:Six patients were found to have no improvement in HFS with the first MVD. All of these patients exhibited excellent improvement after the second MVD. In one patient who had mild improvement with the first MVD, but with more than 50% of remaining spasm, complete abolition of spasm occurred immediately after the second MVD. Six patients showed initial relief and subsequent aggravation of HFS after the first MVD. Of these patients, four had excellent results with the second MVD, one had a good result, and one had a fair outcome. Adverse effects after the second MVD were found in two patients (one patient with permanent mild facial weakness and one patient with hearing impairment). There was no serious morbidity associated with the second MVD. CONCLUSION:Our data suggest that repeat MVD of the facial nerve may be sufficient to resolve symptoms in selected patients with persistent or recurrent HFS. Additionally, three-dimensional short-range magnetic resonance angiography may help to identify the offending vessels and to select the patients with persistent or recurrent HFS.

MR angiographic evaluation is limited in intracranial aneurysms embolized with Nexus coils

IntroductionNexus coils are a type of bioactive coil used to embolize intracranial aneurysms. The purpose of this study was to test the feasibility of the noninvasive follow-up of aneurysms treated with Nexus coils by means of magnetic resonance angiography (MRA).MethodsThree-dimensional (3D) time-of-flight (TOF) MRA images of patients treated with Nexus coils (the Nexus coil group) or bare platinum coils (the control group) were compared for the severity and frequency of artifacts. The reviewers were unaware of the coil types used. In the Nexus coil group, 17 MRA examinations were performed in 14 patients harboring 15 aneurysms treated with Nexus coils using 3-T (n = 11) and 1.5-T (n = 6) MR units. The findings of these examinations were compared to those of 28 MRA studies conducted on 24 control patients (bare platinum coils). Conventional angiograms, maximum intensity projections, and source data of 3D-TOF MRA were reviewed in terms of residual flow within aneurysms and parent arterial patencies. The qualities of the MRA images were rated from grade 0 (no significant signal loss) to grade 2 (complete segmental signal loss of the parent artery). The normalized ratio, defined as the diameter of signal loss on MRA axial source images (in mm) divided by that of coil mass on plain radiographs (in mm), was calculated to compare the sizes of coil-related artifacts in the two groups.ResultsThe quality of the MRA image for the Nexus coil group was significantly poorer than that for the control group (p < 0.0001) due to signal loss caused by the presence of artifacts in the former. In particular, the interpretation of aneurysmal status was impossible in all cases of coiled aneurysms due to segmental signal loss. The sizes of the MRA artifacts were also significantly larger in the Nexus coil group (normalized ratio 1.61 ± 0.22 vs. 1.15 ± 0.20; p < 0.0001).ConclusionFollow-up evaluations by 3D-TOF MRA of aneurysms treated with Nexus coils are severely limited.

Neural stem cells modified by a hypoxia-inducible VEGF gene expression system improve cell viability under hypoxic conditions and spinal cord injury.

Study Design. An in vitro neural hypoxia model and rat spinal cord injury (SCI) model were used to assess the regulation of therapeutic vascular endothelial growth factor (VEGF) gene expression in mouse neural stem cells (mNSCs) by the EPO (erythropoietin) enhancer or RTP801 promoter. Objective. To increase VEGF gene expression in mNSCs under hypoxic conditions in SCI lesions but avoid unwanted overexpression of VEGF in normal sites, we developed a hypoxia-inducible gene expression system consisting of the EPO enhancer and RTP801 promoter fused to VEGF or the luciferase gene, then transfected into mNSCs. Summary of Background Data. On the basis of the ischemic response in the injured area, poor cell survival at the transplantation site is a consistent problem with NSC transplantation after SCI. Although VEGF directly protects neurons and enhances neurite outgrowth, uncontrolled overexpression of VEGF in uninjured tissue may cause serious adverse effects. To effectively improve NSC survival in ischemic sites after transplantation, we evaluated mNSCs modified by a hypoxia-inducible VEGF gene expression system in an SCI model. Methods. Hypoxia-inducible luciferase or VEGF plasmids were constructed using the EPO enhancer or RTP801 promoter. The effect of these systems on targeted gene expression and cell viability was evaluated in mNSCs in both hypoxic in vitro injury and a rat SCI model in vivo. Results. The gene expression system containing the EPO enhancer or RTP801 promoter significantly increased the expression of the luciferase reporter gene and therapeutic VEGF gene under hypoxic conditions. The Epo-SV-VEGF plasmid transfection group had significantly fewer apoptotic cells in vitro. This system also augmented cell viability in the in vivo SCI model. Conclusion. These results strongly suggest the potential utility of mNSCs modified by a hypoxia-inducible VEGF gene expression system in the development of effective stem cell transplantation protocols in SCI.

Concomitant Use of Computer Image Guidance, Linear or Sigmoid Incisions after Minimal Shave, and Liquid Wound Dressing with 2-Octyl Cyanoacrylate for Tumor Craniotomy or Craniectomy: Analysis of 225 Consecutive Surgical Cases with Antecedent Historical Control at One Institution

OBJECTIVERecent neurosurgical literature reflects rapidly evolving, technically enhanced methods that promise to improve neurosurgical outcomes. We review our experience with computer image guidance, linear or sigmoid incisions after minimal shaving, and liquid wound dressing with 2-octyl cyanoacrylate (Dermabond; Ethicon, Inc., Somerville, NJ) for tumor craniotomy or craniectomy in our attempt to optimize craniotomy or craniectomy for tumor. METHODSAfter institutional review board approval, we retrospectively reviewed patients who underwent craniotomy or craniectomy for tumor with or without the combination of techniques specified above. A prior cohort of patients who underwent craniotomy or craniectomy with traditional techniques served as a retrospective basis of comparison. Analysis included in- and outpatient chart reviews, which included the operative notes, pathology reports, discharge summaries, outpatient office records, and intraoperative nursing records. Data were entered into a statistical spreadsheet for analysis and comparison. RESULTSA total of 225 consecutive patients underwent a combination of less invasive techniques from July 2000 through October 2001. These patients were matched with 225 patients in a standard neurosurgical cohort that included patients who underwent operations from July 1994 through July 2000. Age, tumor type, radiation, reoperation rate, tumor location, and extent of resection were comparable for both groups. The overall wound complication rate was significantly lower in the minimally invasive group when compared with the control cohort of patients (0.9% versus 6.2%;P = 0.0298), even for early follow-up (0.9% versus 3.5%;P = 0.0427). Pedicle flap design was a variable that was significantly associated with wound complication. CONCLUSIONModern neurosurgical techniques are beneficial for patients undergoing craniotomy or craniectomy for tumor and seem to be superior to standard techniques. Although the study is multifactorial and retrospective, this conclusion is further supported by the enhanced self-image patients have during the postoperative period.

Role of the oxygen-dependent degradation domain in a hypoxia-inducible gene expression system in vascular endothelial growth factor gene therapy.

Study Design. An in vitro neural hypoxia model and rat spinal cord injury (SCI) model were used to assess the regulation effect of a reporter or therapeutic gene expression by an oxygen-dependent degradation (ODD) domain in a hypoxia-inducible gene expression system with or without the erythropoietin (EPO) enhancer. Objective. To increase vascular endothelial growth factor (VEGF) gene expression in SCI lesions but avoid unwanted overexpression of VEGF in normal sites, we developed a hypoxia-inducible gene expression system consisting of the EPO enhancer upstream of the SV promoter and an ODD domain C-terminally fused to VEGF. Summary of Background Data. ODD domain plays a major role in the degradation of hypoxia-inducible factor 1α and has been used in a hypoxia-specific gene expression system as a post-translational regulatory factor. Methods. The hypoxia-inducible luciferase or VEGF plasmid was constructed using the EPO enhancer combined with or without the ODD domain. The constructed plasmid was transfected into mouse Neuro 2a (N2a) neuroblastoma cells by Lipofectamine 2000, followed by a 24-hour incubation in hypoxia or normoxia. For in vivo analysis, the naked plasmid DNA was directly injected into the injured rat spinal cord. The gene expression was evaluated by luciferase activity assay, enzyme-linked immunosorbent assay, reverse transcriptase-polymerase chain reaction, and immunofluorescence staining. Results. The EPO enhancer/ODD domain-combined hypoxia-inducible gene expression system clearly increased the expression of the reporter luciferase gene and therapeutic VEGF gene specifically under hypoxic conditions and SCI, and quickly downregulated protein expression to a very low level after reoxygenation. Conclusion. These results strongly suggest the potential applicability of this EPO enhancer/ODD domain-based hypoxia-inducible gene expression system in the development of a safer and more effective VEGF gene therapy for SCI.

Traumatic Entrapment of the Vertebrobasilar Junction Due to a Longitudinal Clival Fracture: A Case Report

Vertebrobasilar junction entrapment due to a clivus fracture is a rare clinical observation. The present case report describes a 54-yr-old man who sustained a major craniofacial injury. The patient displayed a stuporous mental state (Glasgow Coma Scale [GCS]=8) and left hemiparesis (Grade 3). The initial computed tomography (CT) scan revealed a right subdural hemorrhage in the frontotemporal region, with a midline shift and longitudinal clival fracture. A decompressive craniectomy with removal of the hematoma was performed. Two days after surgery, a follow-up CT scan showed cerebellar and brain stem infarction, and a CT angiogram revealed occlusion of the left vertebral artery and entrapment of vertebrobasilar junction by the clival fracture. A decompressive suboccipital craniectomy was performed and the patient gradually recovered. This appears to be a rare case of traumatic vertebrobasilar junction entrapment due to a longitudinal clival fracture, including a cerebellar infarction caused by a left vertebral artery occlusion. A literature review is provided.

Retrograde stent placement for coil embolization of a wide-necked posterior inferior cerebellar artery aneurysm

Wide-necked aneurysms of the posterior inferior cerebellar artery (PICA) are infrequently encountered in cerebrovascular practice, and endovascular treatment is difficult or impossible even with the use of several neck remodeling techniques. We present the case of a patient with a wide-necked aneurysm of the PICA, which was treated by the retrograde stenting through the contralateral vertebral artery and vertebrobasilar junction with antegrade coil embolization.

Metachronous schwannoma in the colon with vestibular schwannoma

We experienced a case of vestibular schwannoma and metachronous schwannoma in the colon. A 59-year-old female presented with a 1-month history of hematochezia. She had undergone suboccipital craniectomy resulting in radical subtotal resection, followed by gamma knife radiosurgery for a large left vestibular schwannoma 4 years prior to admission. On preoperative colonoscopy, a huge mass through which the colonoscope could not be passed was detected. CT scans showed colo-colonic intussusception with a 4.8-cm-sized mass in the descending colon. PET/CT revealed hypermetabolism of the descending colon tumor and pericolic lymph nodes. We performed left hemicolectomy under the preoperative impression of colon cancer with intussusception. A pathological diagnosis of benign schwannoma of the colon was made in this patient.

Heat shock protein X purified from Mycobacterium tuberculosis enhances the efficacy of dendritic cells-based immunotherapy for the treatment of allergic asthma

Dendritic cells play an important role in determining whether naïve T cells mature into either Th1 or Th2 cells. We determined whether heat-shock protein X (HspX) purified from Mycobacterium tuberculosis regulates the Th1/Th2 immune response in an ovalbumin (OVA)-induced murine model of asthma. HspX increased interferon-gamma, IL-17A, -12 and transforming growth factor (TGF)-β production and T-bet gene expression but reduced IL-13 production and GATA-3 gene expression. HspX also inhibited asthmatic reactions as demonstrated by an increase in the number of eosinophils in bronchoalveolar lavage fluid, inflammatory cell infiltration in lung tissues, airway luminal narrowing, and airway hyper-responsiveness. Furthermore, HspX enhanced OVA-induced decrease of regulatory T cells in the mediastinal lymph nodes. This study provides evidence that HspX plays critical roles in the amelioration of asthmatic inflammation in mice. These findings provide new insights into the immunotherapeutic role of HspX with respect to its effects on a murine model of asthma. BMB Reports 2015; 48(3): 178-183]

Primary intracranial fibrosarcoma presenting with hemorrhage.

Primary intracranial fibrosarcomas (PIFs) are extremely rare and the origin of these tumors is still controversial. The rarity of primary intracranial fibrosarcomas makes it difficult to diagnose them correctly and establish a standard treatment. The pathologic diagnosis is made by distinguishing findings from light microscopic and immunohistochemistry analysis. PIFs have been known to be very aggressive neoplasms. The extra-axial location of the tumor could provide an opportunity to perform a total resection even if it does not mean a cure. We present a case of PIFs mimicking a falx meningioma in a 17-year-old man.