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Jong Hee Chang, Jin Woo Chang, Yong Gou Park, and Sang Sup Chung

Object. The authors sought to evaluate the effects of gamma knife radiosurgery (GKS) on cerebral arteriovenous malformations (AVMs) and the factors associated with complete occlusion.

Methods. A total of 301 radiosurgical procedures for 277 cerebral AVMs were performed between December 1988 and December 1999. Two hundred seventy-eight lesions in 254 patients who were treated with GKS from May 1992 to December 1999 were analyzed. Several clinical and radiological parameters were evaluated.

Conclusions. The total obliteration rate for the cases with an adequate radiological follow up of more than 2 years was 78.9%. In multivariate analysis, maximum diameter, angiographically delineated shape of the AVM nidus, and the number of draining veins significantly influenced the result of radiosurgery. In addition, margin radiation dose, Spetzler—Martin grade, and the flow pattern of the AVM nidus also had some influence on the outcome. In addition to the size, topography, and radiosurgical parameters of AVMs, it would seem to be necessary to consider the angioarchitectural and hemodynamic aspects to select proper candidates for radiosurgery.

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Jin Woo Chang, Jong Hee Chang, Yong Gou Park, and Sang Sup Chung

Object. The aim of this study was to identify pain relief and treatment morbidity following gamma knife radiosurgery (GKS) for idiopathic and secondary trigeminal neuralgia.

Methods. Between May 1992 and December 1999, 15 patients with idiopathic trigeminal neuralgia and 38 patients with secondary trigeminal neuralgia were treated with GKS. Pain improvement was achieved in 13 of the patients with idiopathic pain (pain response rate 86.7%). Seven patients were pain free and another six experienced pain reduction. There were no serious complications; however, two patients suffered a mild facial sensory change 8 months and 9 months, respectively, after GKS.

The patients with secondary trigeminal neuralgia were divided into two groups (Group I, 32 patients in whom the trigeminal root entry zone [REZ] near the tumor could not be visualized; and Group II, six patients in whom the trigeminal REZ near the tumor or brainstem lesion could be visualized).

In Group I, the pain subsided completely in eight patients and was reduced in seven (pain response rate 46.9%). In Group II, the pain subsided completely in one patient at 2.8 months and was reduced in three patients at a mean follow up of 0.8 months (range 0.6–1 month) after GKS. The pain response rate was 66.7%.

Conclusions. The authors believe that GKS is an effective treatment modalities for idiopathic and secondary trigeminal neuralgia, particularly in patients with inoperable lesions.

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Joong-Uhn Choi, Kook-Hee Yang, Tae-Gon Kim, Jong Hee Chang, Jin Woo Chang, Byung-In Lee, and Dong-Seok Kim

✓ Although intractable epilepsy associated with hypothalamic hamartoma (HH) can be controlled by microsurgical resection of the lesion, excision of deep-seated lesions is often associated with morbidity and mortality. Endoscopic disconnection is less invasive and seems to be well suited for this indication. The authors discuss the role of endoscopic-assisted surgery in the management of HH-induced seizures.

Four patients with HH-related intractable gelastic seizure underwent endoscopic disconnection surgery. Postoperatively, all patients exhibited improvement. Two patients became seizure free immediately after endoscopic disconnection surgery, one patient with a widespread seizure focus involving the motor strip continued to experience rare complex partial seizures but gelastic seizures ceased, and one experienced a reduced frequency of seizures but persistence of some generalized seizures. Three patients suffered postoperative disconnection-like syndrome, which continued 3 to 7 days and spontaneously disappeared.

The authors advocate the endoscopic disconnection surgery as a safe and effective treatment for HH-related epilepsy by blocking the spread of epileptic discharges from the lesion.

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Fatih Incekara, Marion Smits, and Arnaud J. P. E. Vincent

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Dong Wan Kang, Sung Chul Lee, Yong Gou Park, and Jong Hee Chang

Object

Gamma Knife surgery (GKS) is currently believed to be a safe and minimally invasive modality in the treatment of uveal melanomas. It could be used as an alternative treatment to enucleation, preserving the eyeball as well as visual function. The authors report their experiences with GKS for uveal melanomas for the period from February 1998 to December 2006.

Methods

Twenty-two patients with uveal melanoma were enrolled in this study. The population consisted of 12 men and 10 women with a mean age of 53.4 years (range 24–79 years). The mean tumor volume was 877 mm3, and the mean margin dose was 45.6 Gy. The median follow-up period was 67 months (range 3–126 months). All of the patients had received a diagnosis and referral from an ophthalmology clinic; the patients underwent a preoperative orbital examination that included MRI.

Results

Tumor regression was achieved in 20 patients (90.9%), whereas tumor progression was observed in 2 patients (9.1%) 3 years after GKS. The cumulative 1-year and 2-year mean rates of tumor thickness reduction were 18.8% and 42.8%, respectively. The mean rate of tumor volume reduction was 63.7%. The rate of eye retention 5 years after radiosurgery was 77.3% (17 of 22 patients). Overall visual acuity was reduced after GKS in all patients; 14 patients (63.6%) displayed preserved visual function better than hand-movement perception. The most frequent side effect was cataract, which was detected in 9 patients (40.9%); this was followed in frequency by radiation-induced retinopathy in 5 patients (22.7%).

Conclusions

Gamma Knife surgery provides excellent local control of uveal melanomas with a decrease in volume over time. This procedure not only preserves the eyeball and its potential visual function, but also decreases the potential for hematological dissemination and achieves sufficient local tumor control with a gradual reduction in volume.

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Won Seok Chang, Hae Yu Kim, Jin Woo Chang, Yong Gou Park, and Jong Hee Chang

Object

Whole-brain radiation therapy (WBRT), open resection, and stereotactic radiosurgery (SRS) are widely used for treatment of metastatic brain lesions, and many physicians recommend WBRT for multiple brain metastases. However, WBRT can be performed only once per patient, with rare exceptions. Some patients may require SRS for multiple metastatic brain lesions, particularly those patients harboring more than 10 lesions. In this paper, treatment results of SRS for brain metastasis were analyzed, and an attempt was made to determine whether SRS is effective, even in cases involving multiple metastatic brain lesions.

Methods

The authors evaluated the cases of 323 patients who underwent SRS between October 2005 and October 2008 for the treatment of metastatic brain lesions. Treatment was performed using the Gamma Knife model C or Perfexion. The patients were divided into 4 groups according to the number of lesions visible on MR images: Group 1, 1–5 lesions; Group 2, 6–10 lesions: Group 3, 11–15 lesions; and Group 4, > 15 lesions. Patient survival and progression-free survival times, taking into account both local and distant tumor recurrences, were analyzed.

Results

The patients consisted of 172 men and 151 women with a mean age at SRS of 59 years (range 30–89 years). The overall median survival time after SRS was 10 months (range 8.7–11.4 months). The median survival time of each group was as follows: Group 1, 10 months; Group 2, 10 months; Group 3, 13 months; and Group 4, 8 months. There was no statistical difference between survival times after SRS (log-rank test, p = 0.554), although the probability of development of new lesions in the brain was greater in Group 4 (p = 0.014). Local tumor control rates were not statistically different among the groups (log-rank test, p = 0.989); however, remote disease progression was more frequent in Group 4 (log-rank test, p = 0.014).

Conclusions

In this study, patients harboring more than 15 metastatic brain lesions were found to have faster development of new lesions in the brain. This may be due to the biological properties of the patients' primary lesions, for example, having a greater tendency to disseminate hematogenously, especially to the brain, or a higher probability of missed or invisible lesions (microscopic metastases) to treat on stereotactic MR images at the time of radiosurgery. However, the mean survival times after SRS were not statistically different between groups. According to the aforementioned results, SRS may be a good treatment option for local control of metastatic lesions and for improved survival in patients with multiple metastatic brain lesions, even those patients who harbor more than 15 metastatic brain lesions, who, after SRS, may have early and easily detectable new metastatic lesions.

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Yong Sook Park, Jong Hee Chang, Jin Woo Chang, Sang Sup Chung, and Yong Gou Park

Object. The authors describe their experience in treating patients with hemangioblastoma, especially multiple lesions, with gamma knife surgery (GKS).

Methods.Nine patients with 84 hemangioblastomas underwent GKS between July 1992 and May 2003. Three patients harbored a single lesion and six patients had multiple lesions. Of the six patients with multifocal tumors, a diagnosis of von Hippel—Lindau disease had been established in five. In the patients with multiple lesions, the mean radiation dose delivered to the tumor margin was 16.6 Gy (range 12.8–29.75 Gy). The mean margin isodose was 60% (range 40–95%).

Three of the 84 lesions failed to be controlled after a mean follow-up period of 4.3 years (range 8.6–141 months). One patient who had undergone two GKS treatments suffered delayed radiation-induced complications, and posterior fossa decompression and ventriculoperitoneal shunt insertion were required.

Conclusions. To achieve tumor control and avoid morbidity, the surgeon should keep in mind minimizing field overlapping by using a small-diameter collimator or applying a steep dose gradient, and by accurate dose prescription.

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Ji Hee Kim, Hyun Ho Jung, Jong Hee Chang, Jin Woo Chang, Yong Gou Park, and Won Seok Chang

Object

Intracranial chordomas and chondrosarcomas are histologically low-grade, locally invasive tumors that are reported to be similar in terms of anatomical location, clinical presentation, and radiological findings but different in terms of behavior and outcomes. The purpose of this study was to investigate and compare clinical outcomes after Gamma Knife surgery (GKS) for the treatment of intracranial chordoma and chondrosarcoma.

Methods

The authors conducted a retrospective review of the results of radiosurgical treatment of intracranial chordomas and chondrosarcomas. They enrolled patients who had undergone GKS for intracranial chordoma or chondrosarcoma at the Yonsei Gamma Knife Center, Yonsei University College of Medicine, from October 2000 through June 2007. Analyses included only patients for whom the disease was pathologically diagnosed before GKS and for whom more than 5 years of follow-up data after GKS were available. Rates of progression-free survival and overall survival were analyzed and compared according to tumor pathology. Moreover, the association between tumor control and the margin radiation dose to the tumor was analyzed, and the rate of tumor volume change after GKS was quantified.

Results

A total of 10 patients were enrolled in this study. Of these, 5 patients underwent a total of 8 sessions of GKS for chordoma, and the other 5 patients underwent a total of 7 sessions of GKS for chondrosarcoma. The 2- and 5-year progression-free survival rates for patients in the chordoma group were 70% and 35%, respectively, and rates for patients in the chondrosarcoma group were 100% and 80%, respectively (log-rank test, p = 0.04). The 2- and 5-year overall survival rates after GKS for patients in the chordoma group were 87.5% and 72.9%, respectively, and rates for patients in the chondrosarcoma group were 100% and 100%, respectively (log-rank test, p = 0.03). The mean rates of tumor volume change 2 years after radiosurgery were 79.64% and 39.91% for chordoma and chondrosarcoma, respectively (p = 0.05). No tumor progression was observed when margin doses greater than 16 Gy for chordoma and 14 Gy for chondrosarcoma were prescribed.

Conclusions

Outcomes after GKS were more favorable for patients with chondrosarcoma than for those with chordoma. The data also indicated that at 2 years after GKS, the rate of volume change is significantly higher for chordomas than for chondrosarcomas. The authors conclude that radiosurgery with a margin dose of more than 16 Gy for chordomas and more than 14 Gy for chondrosarcomas seems to enhance local tumor control with relatively few complications. Further studies are needed to determine the optimal dose of GKS for patients with intracranial chordoma or chondrosarcoma.

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Eui Hyun Kim, Se Hoon Kim, Jin Mo Cho, Jung Yong Ahn, and Jong Hee Chang

The authors report a case of IgG4-related hypertrophic pachymeningitis that involved cerebral parenchyma. The mass was removed surgically. Histopathological studies showed diffuse infiltration of lymphoplasmacytic cells without evidence of Langerhans histiocytes or meningothelial cells. Immunoglobulin G4 was strongly positive on immunohistochemical staining. The Gd-enhanced lesion deep inside brain parenchyma was completely resolved after 3 months of oral corticosteroid medication. A nodular type of hypertrophic pachymeningitis that mimics a meningioma is rare. Nevertheless, preoperative presumption is very important, and immunohistochemical studies for IgG4 may be helpful in the differential diagnosis.

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Young Seok Park, Jong Hee Chang, Yong Gou Park, and Dong-Seok Kim

Object

The object of this study was to compare the recurrence rates of cystic craniopharyngiomas after neuroendoscopic cyst fenestration combined with Gamma Knife surgery (GKS) and after subtotal resection (STR) combined with GKS.

Methods

The records of 27 patients (age range 3–66 years) with cystic craniopharyngiomas that were treated surgically or neuroendoscopically before GKS between January 2000 and December 2007 were reviewed to compare recurrence rates. The patients were divided into 2 groups: Group 1 (13 patients) received the neuroendoscopic procedure before GKS, and Group 2 (14 patients) received an STR followed by GKS. Tumor volumes, radiation doses, visual field defects, endocrine levels, and recurrences were compared between the 2 groups. Patients with solid tumors and those who underwent complete resection were excluded from the study.

Results

The recurrence rate for Group 1 was higher than that of Group 2 (p = 0.046). The radiation dose near the optic chiasm was higher in Group 1 (p = 0.021) than in Group 2. However, endocrine function was better preserved in Group 1 than in Group 2.

Conclusions

This investigation confirms that STR followed by GKS results in a lower recurrence rate than neuroendoscopy and GKS. Neuroendoscopy and GKS, however, results in a better preservation of endocrine function. These results suggest that a generalized multimodal approach including endoscopic fenestration in addition to GKS is hindered by higher recurrence rates.