Huai-Che Yang

Gamma knife radiosurgery for glomus jugulare and tympanicum.

Objective: To establish the role of gamma knife radiosurgery (GKS) as a treatment strategy for glomus jugulare and tympanicum. Method: A retrospective review of 14 glomus tumors, including 11 glomus jugulare and 3 glomus tympanicum tumors, which were treated by GKS in Taipei Veterans General Hospital from 1993 to 2009, was conducted. Two of these cases had undergone prior surgery with partial tumor resection, and the other 12 cases received primary treatment with GKS after a thorough neuroimaging and cerebral angiography. The tumor volume ranged from 6.5 to 22.1 ml. The maximum dose at the tumor center ranged from 21.6 to 26.3 Gy. All 14 patients were regularly followed up by clinical and radiological evaluations. The median follow-up time was 40.3 months. Results: All 14 patients had significant tumor regression after radiosurgery. The median tumor volume reduction was 34.0% (range 3–79%). Only 1 patient had temporary tumor volume progression (24% increment 6 months post-treatment), accompanied with unilateral facial palsy (from grade III to grade IV) and hearing impairment (from grade I to grade II). The tumor volume of this patient had regressed by 12 months, but facial palsy persisted. The tumor control rate in the series was 100% (n = 14/14), and the preservation rate of cranial nerve function was 92.8% (13/14). There was no complication of lower cranial nerve damage after radiosurgery. Conclusion: GKS appeared to be a good alternative or adjuvant to microsurgical resection in patients who are not amenable to complete surgical eradication, with an excellent tumor control rate and little morbidity after long-term follow-up.

Gamma Knife radiosurgery as a treatment modality for low-grade pediatric brainstem gliomas: report of two cases

Brainstem gliomas, accounting for only 2% of adult brain tumors, constitute 10% to 20% of central nervous system tumors in the pediatric group [3]. They are mainly located in the mesencephalon, the pons (including the cerebellar peduncles), and the medulla oblongata. In pediatric patients, a thorough neurological examination and magnetic resonance (MR) imaging are essential in the establishment of the diagnosis, treatment plans, and therapeutic approaches with or without biopsy [1, 12]. Some case series had proved the therapeutic effect of Gamma Knife radiosurgery (GKS) to brainstem gliomas [4, 8, 15]. For pediatric patients, however, long-term adverse effects caused by radiation injury are always the main concern. In this report, we reviewed our long-term follow-up experience of two pediatric cases with brainstem gliomas after GKS treatment.

Gamma Knife Radiosurgery for Atypical and Anaplastic Meningiomas

BACKGROUND Atypical and anaplastic meningiomas have much higher recurrence rates after surgical resection compared with benign meningiomas, but the role of adjuvant radiosurgery remains unclear. This study was undertaken to evaluate the outcomes of gamma knife radiosurgery for patients with atypical and anaplastic meningiomas. METHODS In this retrospective analysis of a prospectively maintained database, 46 patients with histologically proven atypical or anaplastic meningiomas by current World Health Organization (WHO) criteria underwent postoperative Gamma Knife radiosurgery between 1993 and 2013. The median follow-up period was 32.6 months. The median tumor volume and margin dose were 11.7 mL (range, 2-53 mL) and 13.1 Gy (range, 12.0-16.5 Gy), respectively. RESULTS Local control at 3 and 5 years was 50.6% and 32.1%, respectively. Gender (P = 0.013) and marginal dose less than or equal to 13 Gy (P = 0.049) were associated with the local control. The 3- and 5-year overall survival for patients with WHO grade II was 97.1% and 88.3%, respectively, compared with 66.7% and 66.7% for patients with WHO grade III meningiomas. Radiation therapy before Gamma Knife radiosurgery (GKRS; P = 0.018) and tumor grade (P = 0.019) were the factors associated with a worse overall survival rate. Fourteen patients (30.4%) developed adverse radiation effects after GKRS treatment, and all were Radiation Therapy Oncology Group grade I. CONCLUSIONS Postoperative GKRS treatment for patients with atypical and anaplastic meningioma is challenging. More aggressive treatment, including of safely maximizing the extent of surgical resection and using a higher margin dose (>13Gy), should be applied to achieve better local control.

Application of Time-Resolved 3D Digital Subtraction Angiography to Plan Cerebral Arteriovenous Malformation Radiosurgery

BACKGROUND AND PURPOSE: Time-resolved 3D-DSA (4D-DSA) enables viewing vasculature from any desired angle and time frame. We investigated whether these advantages may facilitate treatment planning and the feasibility of using 4D-DSA as a single imaging technique in AVM/dural arteriovenous fistula radiosurgery. MATERIALS AND METHODS: Twenty consecutive patients (8 dural arteriovenous fistulas and 12 AVMs; 13 men and 7 women; mean age, 45 years; range, 18–64 years) who were scheduled for gamma knife radiosurgery were recruited (November 2014 to October 2015). An optimal volume of reconstructed time-resolved 3D volumes that defines the AVM nidus/dural arteriovenous fistula was sliced into 2D-CT-like images. The original radiosurgery treatment plan was overlaid retrospectively. The registration errors of stereotactic 4D-DSA were compared with those of integrated stereotactic imaging. AVM/dural arteriovenous fistula volumes were contoured, and disjoint and conjoint components were identified. The Wilcoxon signed rank test and the Wilcoxon rank sum test were adopted to evaluate registration errors and contoured volumes of stereotactic 4D-DSA and integration of stereotactic MR imaging and stereotactic 2D-DSA. RESULTS: Sixteen of 20 patients were successfully registered in Advanced Leksell GammaPlan Program. The registration error of stereotactic 4D-DSA was smaller than that of integrated stereotactic imaging (P = .0009). The contoured AVM volume of 4D-DSA was smaller than that contoured on the integration of MR imaging and 2D-DSA, while major inconsistencies existed in cases of dural arteriovenous fistula (P = .042 and 0.039, respectively, for measurements conducted by 2 authors). CONCLUSIONS: Implementation of stereotactic 4D-DSA data for gamma knife radiosurgery for brain AVM/dural arteriovenous fistula is feasible. The ability of 4D-DSA to demonstrate vascular morphology and hemodynamics in 4 dimensions potentially reduces the target volumes of irradiation in vascular radiosurgery.

Gamma Knife Radiosurgery for the Management of Intracranial Dural Arteriovenous Fistulas

BACKGROUND This report presents our 15-year experience with Gamma Knife radiosurgery (GKS) for the treatment of 321 patients with dural arteriovenous fistulas (DAVFs) in different locations. METHODS The most common locations of DAVFs were the cavernous sinus (206 cases) and transverse-sigmoid sinus (72 cases), which together accounted for 86.6 % of cases. In all, 54 patients had undergone embolization or surgery prior to radiosurgery, and the other patients underwent GKS as the primary treatment. During GKS, radiation was confined to the involved sinus wall, which was considered the true nidus of the DAVF. Target volume ranged from 0.8 to 52 cm(3). Marginal and maximum doses to the nidus ranged from 14 to 25 Gy and from 25 to 36 Gy, respectively. RESULTS The mean follow-up time was 28 months (range 2-149 months). In 264 of 321 patients (82 %) available for follow-up study, 173 (66 %) showed complete obliteration of DAVFs with symptomatic resolution, 87 (33 %) had partial obliteration, 2 (0.8 %) had stationary status, 1 (0.4 %) had progression, and 1 (0.4 %) died from a new hemorrhagic episode. Complications were found in only two (0.8 %) patients, one with venous hemorrhage and one with focal brain edema after GKS. CONCLUSIONS GKS is a safe, effective treatment for DAVFs. It provides a minimally invasive therapeutic option for patients who harbor less-aggressive DAVFs but who suffer from intolerable clinical symptoms. For some aggressive DAVFs with extensive venous hypertension or hemorrhage, multimodal treatment with combined embolization or surgery is necessary.

Langerhans’ cell histiocytosis in the pediatric spine: therapeutic dynamic change of spinal deformity

Langerhans’ cell histiocytosis (LCH) is a kind of neoplasm caused by a proliferation of Langerhans’ cells within the tissue. LCH can be classified as a unifocal unisystem (also known as eosinophilic granulation), multifocal unisystem (Hand–Schuller–Christian disease), or multifocal multisystem (Letterer–Siwe disease), based on the area of invasion. Unifocal unisystem disease is the most common and usually presents with a single lytic bone lesion. The incidence of spinal lesion was about 12.5–35 % [5, 15, 23] in all cases of LCH. A single-lesion LCH in the spine is relatively rare, and the typical finding is a vertebra plana with an extradural enhancing mass. The treatment options include simple observation, bracing, bed rest, radiotherapy, chemotherapy, and surgery. Several authors have reported the spontaneous reconstruction of the collapsed vertebra because of its benign clinical course. There is little recorded data on the longterm and dynamic change of spinal deformity. In addition, the use of radiotherapy for spinal lesions has been considered as second-line treatment after the failure of conservative treatment and for patients with neurological deficits in studies during the last 20 years [10, 29]. However, in recent decades, there were few reports discussing about the effect and limitation of radiotherapy. In this study, we present long-term follow-up data for six patients of LCH in the pediatric spine managed with focal low-dose radiotherapy and report the dynamic therapeutic changes.

Quantifying the Cerebral Hemodynamics of Dural Arteriovenous Fistula in Transverse Sigmoid Sinus Complicated by Sinus Stenosis: A Retrospective Cohort Study

BACKGROUND AND PURPOSE: Sinus stenosis occasionally occurs in dural arteriovenous fistulas. Sinus stenosis impedes venous outflow and aggravates intracranial hypertension by reversing cortical venous drainage. This study aimed to analyze the likelihood of sinus stenosis and its impact on cerebral hemodynamics of various types of dural arteriovenous fistulas. MATERIALS AND METHODS: Forty-three cases of dural arteriovenous fistula in the transverse-sigmoid sinus were reviewed and divided into 3 groups: Cognard type I, type IIa, and types with cortical venous drainage. Sinus stenosis and the double peak sign (occurrence of 2 peaks in the time-density curve of the ipsilateral drainage of the internal jugular vein) in dural arteriovenous fistula were evaluated. “TTP” was defined as the time at which a selected angiographic point reached maximum concentration. TTP of the vein of Labbé, TTP of the ipsilateral normal transverse sinus, trans-fistula time, and trans-stenotic time were compared across the 3 groups. RESULTS: Thirty-six percent of type I, 100% of type IIa, and 84% of types with cortical venous drainage had sinus stenosis. All sinus stenosis cases demonstrated loss of the double peak sign that occurs in dural arteriovenous fistula. Trans-fistula time (2.09 seconds) and trans-stenotic time (0.67 seconds) in types with cortical venous drainage were the most prolonged, followed by those in type IIa and type I. TTP of the vein of Labbé was significantly shorter in types with cortical venous drainage. Six patients with types with cortical venous drainage underwent venoplasty and stent placement, and 4 were downgraded to type IIa. CONCLUSIONS: Sinus stenosis indicated dysfunction of venous drainage and is more often encountered in dural arteriovenous fistula with more aggressive types. Venoplasty ameliorates cortical venous drainage in dural arteriovenous fistulas and serves as a bridge treatment to stereotactic radiosurgery in most cases.

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.