Pretemporal trans-Meckel's cave transtentorial approach for large petroclival meningiomas.

OBJECTIVE Despite the advances in skull base techniques, large petroclival meningiomas (PCMs) still pose a challenge to neurosurgeons. The authors' objective of this study was to describe a pretemporal trans-Meckel's cave transtentorial approach for large PCMs and to report the surgical outcomes. METHODS From 2014 to 2017, patients harboring large PCMs (> 3 cm) and undergoing their first resection via this procedure at the authors' institute were included. In combination with pretemporal transcavernous and anterior transpetrosal approaches, the trans-Meckel's cave transtentorial route was created. Surgical details are described and a video demonstrating the procedure is included. Retrospective review of the medical records and imaging studies was performed. RESULTS A total of 18 patients (6 men and 12 women) were included in this study, with mean age of 53 years. The mean sizes of the preoperative and postoperative PCMs were 4.36 cm × 4.09 cm × 4.13 cm (length × width × height) and 0.83 cm × 1.08 cm × 0.75 cm, respectively. Gross-total removal was performed in 7 patients, near-total removal (> 95%) in 7 patients, and subtotal removal in 4 patients (> 90% in 3 patients and > 85% in 1 patient). There were no surgical deaths or patients with postoperative hemiplegia. Surgical complications included transient cranial nerve (CN) III palsy (all patients, resolved in 3 months), transient CN VI palsy (2 patients), CN IV palsy (3 patients, partial recovery), hydrocephalus (3 patients), and CSF otorrhea (1 patient). Temporal lobe retraction-related neurological deficits were not observed. CONCLUSIONS A pretemporal trans-Meckel's cave transtentorial approach offers large surgical exposure and multiple trajectories to the suprasellar, interpeduncular, prepontine, and upper-half clival regions without overt traction, which is mandatory to remove large PCMs. To unlock Meckel's cave where a large PCM lies abutting the cave, pretemporal transcavernous and anterior transpetrosal approaches are prerequisites to create adequate exposure for the final trans-Meckel's cave step.

Comparison of the effectiveness of using the optic strut and tuberculum sellae as radiological landmarks in diagnosing paraclinoid aneurysms with CT angiography.

OBJECTIVE The treatment of paraclinoid aneurysms remains challenging. It is important to determine the exact location of the paraclinoid aneurysm when considering treatment options. The authors herein evaluated the effectiveness of using the optic strut (OS) and tuberculum sellae (TS) as radiographic landmarks for distinguishing between intradural and extradural paraclinoid aneurysms on source images from CT angiography (CTA). METHODS Between January 2010 and September 2013, a total of 49 surgical patients with the preoperative diagnoses of paraclinoid aneurysm and 1 symptomatic cavernous-clinoid aneurysm were retrospectively identified. With the source images from CTA, the OS and the TS were used as landmarks to predict the location of the paraclinoid aneurysm and its relation to the distal dural ring (DDR). The operative findings were examined to confirm the definitive location of the paraclinoid aneurysm. Statistical analysis was performed to determine the diagnostic effectiveness of the landmarks. RESULTS Nineteen patients without preoperative CTA were excluded. The remaining 30 patients comprised the current study. The intraoperative findings confirmed 12 intradural, 12 transitional, and 6 extradural paraclinoid aneurysms, the diagnoses of which were significantly related to the type of aneurysm (p < 0.05) but not factors like sex, age, laterality of aneurysm, or relation of the aneurysm to the ophthalmic artery on digital subtraction angiography. To measure agreement with the correct diagnosis, the OS as a reference point was far superior to the TS (Cohen's kappa coefficients 0.462 and 0.138 for the OS and the TS, respectively). For paraclinoid aneurysms of the medial or posterior type, using the base of the OS as a reference point tended to overestimate intradural paraclinoid aneurysms. The receiver operating characteristic curve indicated that if the aneurysmal neck traverses the axial plane 2 mm above the base of the OS, the aneurysm is most likely to grow across the DDR and present as a transitional aneurysm (sensitivity 0.806; specificity 0.792). CONCLUSIONS High-resolution thin-cut CTA is a fast and crucial tool for diagnosing paraclinoid aneurysms. The OS serves as an effective landmark in CTA source images for distinguishing between intradural and extradural paraclinoid aneurysms. The DDR is supposed to be located 2 mm above the base of the OS in axial planes.

Microsurgical technique of symptomatic intracavernous aneurysm.

Symptomatic intracavernous aneurysm is rare. Cranial nerves in the cavernous sinus are subjected to the mass effect of an expanding aneurysm. Microsurgical clipping is the treatment of choice to relieve compressive cranial neuropathy. In this video, the authors present a case of intracavernous aneurysm causing diplopia, ptosis, and facial numbness. The patient was operated on via a pretemporal transclinoid-transcavernous approach. The aneurysm was completely obliterated through direct clipping. There were no new-onset neurologic deficits and complications after the operation. Complete recovery of the diplopia, ptosis, and facial numbness was observed at the 6-month postoperative follow up. The video can be found here: http://youtu.be/4w5QUoNIAQM.

Fluorescence-assisted visualization of facial nerve during mastoidectomy: A novel technique for preventing iatrogenic facial paralysis.

OBJECTIVE: Mastoidectomy can be risky due to the chance of iatrogenic facial nerve dysfunction. Avoiding injuries to the mastoid segment of the facial nerve is mandatory when drilling the bone. With advancements in intraoperative near-infrared indocyanine green (ICG) video angiography, we describe the application of a novel fluorescent guidance technique during mastoidectomies to identify the facial canal with safety. METHODS: Mastoidectomies were performed as the key step in the presigmoid, petrosal or translabyrinthine approaches in 16 patients with different pathologies located at the cerebellopontine angle or petroclival region. After the facial canal was drilled to paper thin, ICG was injected via the central venous catheter. Compared with the dark bony portion, the vessels inside the vasa nervorum were highlighted as a result. The fluorescence guides the operator through the course of the facial nerve and facilitates opening of the internal auditory canal and the dissection of tumors. RESULTS: All 16 facial nerves were recognized during mastoidectomies under fluorescence guidance for varied periods of enhancing time (range, 23-50s). In all, one to four attempts after repeated drilling works to enhance the facial nerve were required before these nerves could be clearly seen. The tumor resection procedure yielded the following results: grossly total removal in seven patients, near total removal in five, and subtotal removal in three. Complete obliteration of a giant vertebral artery aneurysm in one patient was seen in the follow-up angiogram. The post-mastoidectomy facial nerve function, examined by triggered EMG, was preserved in all 16 patients, and no patients had postoperative facial palsy worse than House-Brackmann grade IV after 6 months of follow-up. CONCLUSION: With this novel technique, the course of the facial nerve can be confirmed during mastoidectomy, which reduces the possibility of iatrogenic facial nerve dysfunction. This fluorescence technique is especially helpful in establishing confidence and shortening the learning curve for beginners at mastoidectomies.

Bilobulated paraclinoid aneurysm mimics double aneurysms: a comparison of endovascular coiling and surgical clipping treatments.

This report presents two cases of subarachnoid hemorrhage caused by rupture of paraclinoid aneurysms. Both aneurysms presented a bilobulated appearance upon image study. Both cases were treated successfully, the first with surgical clipping and the second with endovascular coiling. The special bilobulated feature of paraclinoid aneurysm in this particular anatomic location suggests its close relationship with the carotid dural ring. This relationship caused varying degrees of difficulty in both coiling and clipping the aneurysm. We compared the limitations and advantages of both treatments, and suggest that surgical clipping may be the treatment of choice in this region.

Rhabdoid glioblastoma: a recently recognized subtype of glioblastoma.

BACKGROUND: Rhabdoid glioblastoma is a rare type of recently described malignant brain tumor. It is characterized by a glioblastoma associated with rhabdoid components. METHODS: Here we report two cases of rhabdoid glioblastoma and a brief literature review. The first patient was a 19-year-old boy who initially presented with a foul-smelling odor and progressive right-side weakness. The second case was a 29-year-old male patient who presented only with a severe headache. RESULTS: Both of these patients were young, and the disease progression was quick despite optimal treatment. CONCLUSION: The diagnosis of rhabdoid glioblastoma was confirmed after microscopic and immunohistochemical findings.

Direct measurement of the signal intensity of diffusion-weighted magnetic resonance imaging for preoperative grading and treatment guidance for brain gliomas.

BACKGROUND: Magnetic resonance diffusion-weighted imaging (DWI) has been widely used clinically in imaging diagnosis of intracranial disorders. The purpose of current study was to present a quantitative method of direct measuring the DWI signal intensity of brain gliomas on the monitors of hospital picture archiving and communicating system (PACS) for grading gliomas. METHODS: This study recruited 135 patients with treatment-naïve brain gliomas. Direct measurement of the signal intensity of selected tumoral regions of interest (ROIs) by DWI on the monitors of the hospital PACS was performed for all patients. From the measurements, we obtained three values, defined as DWI(T) (tumor), DWI(N) (the homologous normal-appearing area of the tumor ROI in the contralateral hemisphere), and DWI(WM) (normal-appearing white matter) in the contralateral frontal lobe. Two ratios, DWI(T/WM) and DWI(T/N), were obtained for each tumoral ROI. The same method was used for apparent diffusion coefficient (ADC) ratios of the tumoral ROI. Fractional polynomial regression and the Mann-Whitney U test were applied to determine the correlation between tumor grading, MIB-1 labeling index, and DWI and ADC ratios. Logistic regression models and receiver operating characteristic curve analysis were used to establish diagnostic models. Measurements of intraobserver and interobserver agreement were also made at 1-month interval. RESULTS: The DWI ratios correlated positively with tumor grade and MIB-1 value (p < 0.01). Cut-off ratios of 1.62 for DWI(T/WM) and 1.47 for DWI(T/N) generated the optimal combination of sensitivity (0.82, 0.80), specificity (0.79, 0.86), and sound discriminating power, with an area under the curve of 0.87 and 0.84, respectively, to differentiate low-grade from high-grade gliomas. ADC ratios showed relatively worse sensitivity, specificity, and discriminating power than DWI ratios. Almost all intraobserver and interobserver measurements were within 95% agreement. CONCLUSION: The proposed method - direct measuring of tumor signal intensity of DWI on PACS monitors - is feasible for grading gliomas in clinical neuro-oncology imaging services and has a high level of reliability and reproducibility.

Immediate results of microsurgical clipping of posterior communicating artery aneurysms using the pretemporal transclinoidal approach.

BACKGROUND: We evaluated adverse ischemic events as early surgical results of microsurgical clipping of 44 and 34 posterior communicating artery (PComA) aneurysms through the pterional transsylvian and pretemporal transclinoidal approach, respectively, between January 2007 and October 2010. METHODS: Patients undergoing PComA aneurysm clipping were divided into two groups, and their immediate surgical results were compared and analyzed. Those who underwent the pterional transsylvian approach (group A) comprised 42 patients with 44 PComA aneurysms (24 ruptured and 20 unruptured). Those who underwent the pretemporal transclinoidal approach (group B) comprised 32 patients with 34 PComA aneurysms (20 ruptured and 14 unruptured). RESULTS: The immediate postoperative total occlusion rates were 97.7% in group A and 100% in group B. The pretemporal transclinoidal approach significantly reduced the overall risk of silent and symptomatic ischemic strokes (p = 0.04) in ruptured PComA clippings and tended to lower the incidence of intraoperative aneurysm rupture (p = 0.07) as well as the overall ischemic events (p = 0.06) in a total of 78 aneurysm clippings, as compared with the pterional transsylvian approach. Although not significantly, the pretemporal transclinoidal approach also tended to have a lower incidence of intraoperative aneurysm rupture in ruptured aneurysm clippings (p = 0.11), which were mainly responsible for the symptomatic ischemia. The pretemporal transclinoidal approach had no additional advantage over the traditional pterional transsylvian approach in unruptured PComA aneurysm clippings in the present study. CONCLUSION: The pretemporal transclinoidal approach achieved better visualization of the vital neurovascular structures surrounding PComA aneurysms, which might be a key improvement in lowering the risk of intraoperative aneurysm rupture and obtaining significantly satisfactory immediate surgical results in the microsurgical clipping of PComA aneurysms, especially ruptured ones.

An easy adjustable method of ectatic vertebrobasilar artery transposition for microvascular decompression.

BACKGROUND: Microvascular decompression (MVD) of trigeminal neuralgia (TN) or hemifacial spasm (HFS) caused by an elongated, tortuous or enlarged vertebral or basilar artery has a higher rate of incomplete cure. OBJECTIVE: We used an easily applied and adjustable method of vertebrobasilar artery transposition and fixation to improve the immediate surgical outcome of MVD of TN or HFS due to compression by an ectatic vertebrobasilar artery system. METHODS: Vertebral or basilar artery transposition was performed using the vascular sling with a strip of unabsorbable dural tape. The vertebrobasilar artery-sling complex was then fixed to the dura over the petrous bone by aneurysm clip through the dural bridge. The direction and angle of traction on the vertebrobasilar artery was adjustable using different lengths of clip or the horizontal level of the dural bridge. RESULTS: The sling and clip fixation method has been applied in 7 cases of MVD associated with vertebral or basilar artery compression. All 3 patients with TN and one with HFS had total remission of symptoms right after the procedure; one patient was completely free of spasm within 1 week after MVD and one had achieved 80% improvement of spasm in his last clinical visit 3 months after MVD. There was no major surgical complication in these 7 patients. Surprisingly, refractory hypertension was unexpectedly cured in one patient with TN following the procedure. CONCLUSION: The vertebrobasilar artery transposition and fixation method used in the present study provided surgeons an easy and adjustable way to perform MVD safely and effectively.

A proposed mechanism of superficial siderosis supported by surgical and neuroimaging findings.

Superficial siderosis is a rare disease with a low incidence of known etiologies and successful management in clinical practice. The presence of a fluid collection secondary to a dural tear has been reported in patients and is considered to be related to superficial siderosis. We report on a patient with superficial siderosis who had a multi-lobulated arachnoid cyst incarcerating the inner dural layer and showing rhythmic pulsations indicating the free connection with cerebrospinal fluid (CSF) circulation. Surgical removal of the arachnoid cyst and leakage repair halted the progression of clinical impairment and reduced epidural fluid collection shown by post-operative magnetic resonance myelogram. Based on the surgical and neuroimaging findings, especially the heavily T2-weighted MR myelogram, we propose a hypothesis, increased epidural pressure microtraumatizing the fragile internal venous plexus leading to recurrent microbleeding, to explain the formation of the superficial siderosis.

Decision model for acute appendicitis treatment with decision tree technology--a modification of the Alvarado scoring system.

BACKGROUND: How to decide the proper time to do laparotomies for acute appendicitis patients is sometimes very difficult, especially in areas with no imaging diagnostic tools. The Alvarado scoring system (ASS) is a convenient and inexpensive decision making tool; however, its accuracy needs to be improved. The decision tree is the most frequently used data mining technology for diagnostic model building. This study used a decision tree to modify the ASS and to prioritize the variables. METHODS: We collected 532 patients who underwent appendectomy. Patients who had undergone incidental appendectomy were excluded from the study. The decision tree algorithm was constructed with the data mining workbench Clementine version 8.1. It is a top-down algorithm designed to generate a decision tree model with entropy. The algorithm chooses the best decision node with which to separate different classes from empirical data. The Wilcoxon signed rank test, Student t test and chi(2) test were used for statistical analysis. RESULTS: Among the 532 patients recruited into the study, 420 had acute appendicitis and 112 had normal appendix. Women with acute appendicitis were older than their male counterparts (p < 0.001). All patients had right lower quadrant tenderness. The new model was constructed with decision tree technology, and the accuracy of the diagnostic rate was better than that of ASS (p < 0.001). The sensitivity and specificity of the new model were 0.945 and 0.805, respectively. CONCLUSION: The new model is more convenient and accurate than ASS. Right lower quadrant tenderness is an inclusion criterion for acute appendicitis diagnosis. Migrating pain and neutrophil count > 75% were significant factors for acute appendicitis diagnosis if ASS score < 6. Although the criteria of nausea/vomiting and white blood cell count > 10,000/dL were significantly different between acute appendicitis and normal appendix, there was no significant contribution of entropy change below the "neutrophil count > 75%" nodes in the model. So they were erased from the decision tree model. Further studies need to be conducted to investigate why older women are at higher risk for acute appendicitis.

Olfactory ensheathing cell tumor with neurofibroma-like features: a case report and review of the literature.

A 32-year-old man had seizure attack since April 2008 and radiographic examination revealed a heterogeneous enhancing mass at the left subfrontal region. He underwent craniotomy for tumor removal on October 1, 2008. The tumor, which was grayish white with glistening appearance and rubbery consistency, was traced to the proximal part of left olfactory tract. Histopathological examination revealed a hypocellular tumor with dense hyalinization in most areas. The tumor cells had ovoid to elongate and often comma-shaped nucleus. Myxoid change of the stroma was apparent in places. Most of the tumor cells were immuno-reactive for S-100 protein. Staining for Leu 7 (CD57 or HNK-1) was negative. Bodian method illustrated many axons within the tumor. Ultrastructural study of the tumor cells showed features compatible with those of olfactory ensheathing cell. The tumor was designated as olfactory ensheathing cell tumor with neurofibroma-like features. There have been 14 nerve sheath tumors arising from the olfactory nerve reported in the literature; all of them had the morphology of schwannoma. Our case, which had the morphology simulating neurofibroma was the first of its kind to be recorded.

Primary intradural hemangiopericytoma with intramedullary invasion.

Hemangiopericytoma (HPC) is a rare tumor of the central nervous system and is usually found intracranially. Intraspinal HPCs are very rare and mostly involve the extradural bony structures. Primary intradural HPC has only been reported in 10 cases, all of which occurred in the extramedullary region. Intramedullary invasion has never been reported. Here, we describe a case of primary intradural HPC of the thoracic spine that presented initially with paresthesia and paraplegia of both legs. Magnetic resonance imaging of the thoracic spine showed an intradural dumbbell-shaped tumor at the T10 level. The initial impression was neurogenic tumor, meningioma, or metastasis. During operation, the tumor was found to have obvious intramedullary invasion. Gross-total removal was done, and the patient's neurological function improved; there was no recurrence at the 3-year follow-up. There is no consensus as to what constitutes the optimal treatment of HPC, but most neurosurgeons will advocate gross-total resection. A comparative analysis between intradural and extradural HPCs showed a higher chance of gross-total resection for intradural HPCs, while the recurrence rates showed no difference. The role of adjuvant radiotherapy remains uncertain. Due to the high risk of recurrence and metastasis of HPCs, close follow-up for a long period is mandatory.

Idiopathic hypereosinophilic syndrome with infiltration of cerebrospinal fluid by immature eosinophils: a case report and literature review.

BACKGROUND: Idiopathic hypereosinophilic syndrome is characterized by persistent hypereosinophilia with end organ damage and no definite underlying cause. It has been recognized that eosinophils can induce varying degrees of neural damage. There are only a few reports in the literature regarding CSF by eosinophils, and the relationship between hypereosinophilic syndrome and eosinophilic leukemia remains unclear. CASE DESCRIPTION: We report a case of IHS with CSF infiltration by immature eosinophils and significant subdural effusion with underlying brain parenchyma compression. He was treated by inserting a subdural-peritoneal shunt with improvement. Respiratory distress and pulmonary infiltration with eosinophils developed. Imatinib mesylate (Gleevec) was added with improvement, and subsequent CSF study showed normalization of CSF cytology analysis. However, re-collection of subdural fluid developed later and resulted in consciousness disturbance, and the patient died thereafter. CONCLUSION: Idiopathic hypereosinophilic syndrome remains a serious condition with a poor prognosis for most patients. Cerebrospinal fluid infiltration by immature eosinophils is a rare condition in IHS and may lead to poor prognosis, as observed in this patient, despite improved medical management (steroid and imatinib mesylate) and adequate surgical shunting for the subdural effusion.

Posterior inferior cerebellar artery with extracranial origin harboring an extracranial aneurysm.

BACKGROUND: We report on a rare case of a saccular aneurysm on the TM segment of the right PICA. The aneurysm was located at the nonbifurcation region of the PICA. CASE DESCRIPTION: The patient underwent a brain CT scan that revealed a diffuse SAH and an IVH in the fourth ventricle with obstructive hydrocephalus. After external ventricular drainage to relieve the hydrocephalus, the aneurysm was demonstrated by cerebral digital subtraction angiography. CONCLUSIONS: The origin of the PICA aneurysm was extracranial and intradural, illustrating a rare location of such type of aneurysm.

Treatment of spinal cord ependymomas by surgery with or without postoperative radiotherapy.

PURPOSE: To evaluate the effectiveness of complete resection and postoperative radiotherapy in spinal cord ependymomas. METHODS AND MATERIALS: We conducted a retrospective study over 20 patients (13 males and 7 females) with histologically confirmed spinal cord ependymomas between July 1985 and April 2001. Among them, 13 patients had ependymomas, 6 had myxopapillary ependymomas, and 1 had anaplastic ependymoma. All patients received radical surgery for tumor removal with 13 patients achieving complete resection and 7 incomplete resection due to technical difficulty. Among those with incomplete resection, 6 patients received postoperative radiotherapy to tumor bed and only one patient with anaplastic ependymoma received surgery alone. The total tumor dose ranged from 50 to 60 Gy. RESULTS: Among the 20 patients, 19 patients were alive and showed local control. The median survival time of all patients was 109 months, with 104 months in the complete resection alone group and 135 months in the incomplete resection with postoperative radiotherapy group. One patient with anaplastic ependymoma and no postoperative radiotherapy developed leptomeningeal seeding 9 months after surgery. Salvage therapy of radiotherapy and chemotherapy maintained normal neurological functions. The patient expired 34 months from the initial diagnosis due to progression of leptomeningeal seeding. CONCLUSION: Complete resection alone in spinal cord ependymoma can achieve excellent local control and survival. Patients should receive complete resection if technically possible. Postoperative radiotherapy is not recommended for complete resection. For incomplete resection, postoperative local radiotherapy is recommended and it can also achieve excellent local control and survival. Local radiotherapy with 50-60 Gy is effective and safe. Salvage radiotherapy improves quality of life for local recurrence or leptomeningeal seeding patients.

Massive hemoptysis caused by endobronchial schwannoma in a patient with neurofibromatosis 2.

Neurogenic tumor of the lung is very uncommon. To the best of our knowledge, endobronchial schwannoma complicated by massive hemoptysis in a patient with neurofibromatosis 2 has not been reported previously. We report a case of endobronchial schwannoma complicated by massive hemoptysis in an 18-year-old man with neurofibromatosis 2. The diagnosis of neurofibromatosis 2 was established by demonstration of bilateral vestibular schwannomas on magnetic resonance imaging of the brain and pathologic examination of the resected brain tumors. Massive hemoptysis developed after surgical removal of the brain tumors in this patient. Bronchoscopy was done immediately after the first episode of hemoptysis and a tumor protruding from the orifice of the right lower lobe bronchus was found. Despite 2 additional bronchoscopies to stop bleeding and ameliorate airway obstruction in the consecutive 2 days, hemoptysis recurred rapidly and caused profound oxygen desaturation. The patient was subjected to right lower lobectomy and endobronchial schwannoma was evidenced pathologically.