A Clinical Analysis of Secondary Surgery in Trigeminal Neuralgia Patients Who Failed Prior Treatment

OBJECTIVE: Although many treatment modalities have been introduced for trigeminal neuralgia (TN), the long-term clinical results remain unsatisfactory. It has been particularly challenging to determine an appropriate treatment strategy for patients who have responded poorly to initial therapies. We analyzed the surgical outcomes in TN patients who failed prior treatments. METHODS: We performed a retrospective analysis of 37 patients with recurrent or persistent TN symptoms who underwent surgery at our hospital between January 2010 and December 2014. Patients with follow-up data of at least one year were included. The prior treatment modalities of the 37 patients included microvascular decompression (MVD), gamma knife radiosurgery (GKRS), and percutaneous procedures such as radiofrequency rhizotomy (RFR), balloon compression, and glycerol rhizotomy (GR). The mean follow-up period was 69.9 months (range : 16–173). The mean interval between the prior treatment and second surgery was 26 months (range : 7–123). We evaluated the surgical outcomes using the Barrow Neurological Institute (BNI) pain intensity scale. RESULTS: Among the 37 recurrent or persistent TN patients, 22 underwent MVD with partial sensory rhizotomy (PSR), 8 received MVD alone, and 7 had PSR alone. Monitoring of the surgical treatment outcomes via the BNI pain intensity scale revealed 8 (21.6%) patients with a score of I, 13 (35.1%) scoring II, 13 (35.1%) scoring III, and 3 (8.2%) scoring IV at the end of the follow-up period. Overall, 91.8% of patients had good surgical outcomes. With regard to postoperative complications, 1 patient had transient cerebrospinal fluid rhinorrhea (2.7%), another had a subdural hematoma (2.7%), and facial sensory changes were noted in 8 (21.1%) patients after surgery. CONCLUSION: Surgical interventions, such as MVD and PSR, are safe and very effective treatment modalities in TN patients who failed initial or prior treatments. We presume that the combination of MVD with PSR enabled us to obtain good short- and long-term surgical outcomes. Therefore, aggressive surgical treatment should be considered in patients with recurrent TN despite failure of various treatment modalities.

Trigeminal Neuralgia Caused by Persistent Primitive Trigeminal Artery

A 66-year-old man presented with typical trigeminal neuralgia (TN). Magnetic resonance angiography (MRA) revealed a primitive trigeminal artery (PTA) that came into contact with the trigeminal nerve. Based on MRA, we performed microvascular decompression (MVD). In the operational field, we confirmed the PTA location and performed MVD successfully. Postoperatively, the patient's pain subsided without any complications.

Trigeminal Neuralgia Caused by Persistent Primitive Trigeminal Artery

A 66-year-old man presented with typical trigeminal neuralgia (TN). Magnetic resonance angiography (MRA) revealed a primitive trigeminal artery (PTA) that came into contact with the trigeminal nerve. Based on MRA, we performed microvascular decompression (MVD). In the operational field, we confirmed the PTA location and performed MVD successfully. Postoperatively, the patient's pain subsided without any complications.

A Comparative Analysis of Chronic Subdural Hematoma in Two Age Groups of Younger and Older than 75 Years / 대한신경손상학회지

OBJECTIVE: Chronic subdural hematoma (cSDH) is one of the most common types of intracranial hemorrhage. As the number of elderly people is increasing, the incidence of cSDH is growing. Therefore, we analyzed clinical manifestation of the cSDH. METHODS: The authors retrospectively reviewed the data of the 169 patients of cSDH who were 65 years or older and undergone burr-hole trephination and closed drainage in our hospital between January 2008 and December 2012. Patients were divided into two subgroups; group A: young than 75 years, group B: 75 years or older. We analyzed the differences of clinical aspects and surgical results in both groups. RESULTS: Proportion of male patients in group A (83.8%) was higher than in group B (58.4%) with statistical significance (p=0.003). Alteration of consciousness as an initial symptom was significantly more frequent in group A (17.5%) than in group B (4.4%)(p=0.006). Postoperatively, 164 of 169 patients (97%) were free from symptom within three days in both groups. Pneumonia followed the surgery in three patients (one in group A and two in group B). CONCLUSION: There were no difference in the rate of complications between group A and B. Therefore, burr-hole trephination and external drainage is safe and effective management in both groups.

Traumatic Delayed Subdural Hematoma Accompanied Acute Cerebral Infarction during Anticoagulant Therapy in an Old Patient / 대한신경손상학회지

Oral anticoagulant therapy is generally being used in patient with a high thromboembolic risk such as cerebrovascular or cardiovascular accident, in spite of increased bleeding tendencies and most of them are old-age patients. A stroke frequently leads to a fall, which in turn causes a minor trauma, and it is often reported that anticoagulant therapy for treatment of stroke may aggravate traumatic brain injury. The authors report a case that required surgical treatments for subacute subdural hematoma which was found during antiplatelets and anticoagulant therapy for acute ischemic stroke. The hematoma had not been found at the time of head injury accompanied by a cerebral infarction.

Traumatic Delayed Subdural Hematoma Accompanied Acute Cerebral Infarction during Anticoagulant Therapy in an Old Patient / 대한신경손상학회지

Oral anticoagulant therapy is generally being used in patient with a high thromboembolic risk such as cerebrovascular or cardiovascular accident, in spite of increased bleeding tendencies and most of them are old-age patients. A stroke frequently leads to a fall, which in turn causes a minor trauma, and it is often reported that anticoagulant therapy for treatment of stroke may aggravate traumatic brain injury. The authors report a case that required surgical treatments for subacute subdural hematoma which was found during antiplatelets and anticoagulant therapy for acute ischemic stroke. The hematoma had not been found at the time of head injury accompanied by a cerebral infarction.

Hemifacial Spasm Developed after Contralateral Vertebral Artery Ligation

Although the mechanism of hemifacial spasm (HFS) is not yet well established, vascular compression of the facial nerve root exit zone and hyperexcitability of the facial nucleus have been suggested. We report a case of HFS in the setting of coinciding intracranial hemorrhage (ICH) of the pons and proximal ligation of the contralateral vertebral artery (VA) for the treatment of a fusiform aneurysm of the distal VA and discuss the possible etiologies of HFS in this patient. A 51-year-old male with an ICH of the pons was admitted to our hospital. Neuroimaging studies revealed an incidental fusiform aneurysm of the right VA distal to the origin of the posterior inferior cerebellar artery. Eight months after proximal ligation of the VA the patient presented with intermittent spasm of the left side of his face. Pre- and post-ligation magnetic resonance angiography revealed an enlarged diameter of the VA. The spasm completely disappeared after microvascular decompression.

Multi-Modality Treatment for Intracranial Arteriovenous Malformation Associated with Arterial Aneurysm

OBJECTIVE: Intracranial arteriovenous malformation (AVM) associated with aneurysm has been infrequently encountered and the treatment for this malady is challenging. We report here on our clinical experience with AVMs associated with arterial aneurysms that were managed by multimodality treatments, including clipping of the aneurysm, microsurgery, Gamma-knife radiosurgery (GKS) and Guglielmi detachable coil (GDC) embolization. METHODS: We reviewed the treatment plans, radiological findings and clinical courses of 21 patients who were treated with GKS for AVM associated with aneurysm. RESULTS: Twenty-seven aneurysms in 21 patients with AVMs were enrolled in this study. Hemorrhage was the most frequent presenting symptom (17 patients : 80.9%). Bleeding was caused by an AVM nidus in 11 cases, aneurysm rupture in 5 and an undetermined origin in 1. Five patients were treated for associated aneurysm with clipping followed by GKS for the AVM and 11 patients were treated with GDC embolization combined with GKS for an AVM. Although 11 associated aneurysms remained untreated after GKS, none of them ruptured and 4 aneurysms regressed during the follow up period. Two aneurysms increased in size despite the disappearance of the AVM nidus after GKS and then these aneurysms were treated with GDC embolization. CONCLUSION: If combined treatment using microsurgery, GKS and endovascular treatment can be adequately used for these patients, a better prognosis can be obtained. In particular, GKS and GDC embolization are considered to have significant roles to minimize neurologic injury.

Radiosurgical Considerations in the Treatment of Large Cerebral Arteriovenous Malformations

OBJECTIVE: In order to establish the role of Gamma Knife radiosurgery (GKS) in large intracranial arteriovenous malformations (AVMs), we analyzed clinical characteristics, radiological features, and radiosurgical outcomes. METHODS: Between March 1992 and March 2005, 28 of 33 patients with large AVMs (> 10 cm3 in nidus-volume) who were treated with GKS underwent single session radiosurgery (RS), and the other 5 patients underwent staged volumetric RS. Retrospectively collected data were available in 23 cases. We analyzed treatment outcomes in each subdivided groups and according to the AVM sizes. We compared the estimated volume, defined as primarily estimated nidus volume using MR images, with real target volume after excluding draining veins and feeding arteries embedded into the nidus. RESULTS: Regarding those patients who underwent single session RS, 44.4% (8/18) had complete obliteration; regarding staged volumetric RS, the obliteration rate was 40% (2/5). The complete obliteration rate was 60% (6/10) in the smaller nidus group (10-15 cm3 size), and 25% (2/8) in the larger nidus group (over 15 cm3 size). One case of cerebral edema and two cases (8.7%) of hemorrhage were seen during the latent period. The mean real target volume for 18 single sessions of RS was 17.1 cm3 (10.1-38.4 cm3), in contrast with the mean estimated volume of 20.9 cm3 (12.0-45.0 cm3). CONCLUSION: The radiosurgical treatment outcomes of large AVMs are generally poor. However, we presume that the recent development in planning software and imaging devices aid more accurate measurement of the nidus volume, therefore improving the treatment outcome.

Hemifacial Spasm Caused by Epidermoid Tumor at Cerebello Pontine Angle

Hemifacial spasm (HFS) is almost always induced by vascular compression but in some cases the cause of HFS are tumors at cerebellopontine angle (CPA) or vascular malformations. We present a rare case of hemifacial spasm caused by epidermoid tumors and the possible pathogenesis of HFS is discussed. A 36-year-old female patient presented with a 27-month history of progressive involuntary facial twitching and had been treated with acupuncture and herb medication. On imaging study, a mass lesion was seen at right CPA. Microvascular decompression combined with mass removal was undertaken through retrosigmoid approach. The lesion was avascular mass and diagnosed with an epidermoid tumor pathologically. Eventually, we found a offending vessel (AICA : anterior inferior cerebellar artery) compressing facial nerve root exit zone (REZ). In case of HFS caused by tumor compression on the facial nerve REZ, surgeons should try to find an offending vessel under the mass. This case supports the vascular compression theory as a pathogenesis of HFS.

The Treatment Outcome of Elderly Patients with Idiopathic Trigeminal Neuralgia : Micro-Vascular Decompression versus Gamma Knife Radiosurgery

OBJECTIVE: This study was designed to compare the efficacy of micro-vascular decompression (MVD) and Gamma knife radiosurgery (GKRS) for elderly idiopathic trigeminal neuralgia patients by analyzing the clinical outcome. METHODS: In the past 10 years, 27 elderly patients were treated with MVD while 18 patients were treated with GKRS (>65-years-old). We reviewed their clinical characteristics and clinical courses after treatment as well as the treatment outcomes. For patients who were treated with MVD, additional treatment methods such as rhizotomy were combined in some areas. In GKRS, we radiated the root entry zone (REZ) with the mean maximum dose of 77.8 (70-84.3) Gy and one 4 mm collimator. RESULTS: The mean age was 68.1 years for MVD, and 71.1 years for GKS group. The average time interval between first presenting symptom and surgery was 84.1 (1-361) months, and 51.4 (1-120) months, respectively. The mean follow-up period after the surgery was 35.9 months for MVD, and 33.1 months for GKRS. According to Pain Intensity Scale, MVD group showed better prognosis with 17 (63%) cases in grade I-II versus 10 (55.6%) cases in GKRS group after the treatment. The pain recurrence rate during follow up did not show much difference with 3 (11.1%) in MVD, and 2 (11.1%) in GKRS. After the treatment, 2 cases of facial numbness, and 1 case each of herpes zoster, cerebrospinal fluid (CSF) leakage, hearing disturbance, and subdural hematoma occurred in MVD Group. In GKRS, there was 1 (5.6%) case of dysesthesia but was not permanent. Three cases were retreated by GKRS but the prognosis was not as good as when the surgery was used as primary treatment, with 1 case of grade I-II, and 1 case of recurrence. The maximal relieve of pain was seen just after surgery in MVD group, and 1 year after treatment in GKRS group. CONCLUSION: For trigeminal neuralgia patients with advanced age, MVD showed advantages in immediately relieving the pain. However, in overall, GKRS was preferable, despite the delayed pain relief, due to the lower rate of surgical complications that arise owing to the old age.

Hemifacial Spasm Caused by Fusiform Aneurysm at Vertebral Artery-Posterior Inferior Cerebellar Artery Junction

Hemifacial spasm induced by intracranial aneurysm is a rare clinical condition. A 45-year-old male patient presented with a 3-year history of progressive involuntary twitching movement on right face. On radiological study, a dilated vascular lesion compressing the brain stem was found at the junction of vertebral artery and posterior inferior cerebellar artery. On operative field, we found the posterior inferior cerebellar artery and the fusiform aneurysm compressing root exit zone of facial nerve. Microvascular decompression was performed and the facial symptom was relieved without complications.

Microvascular Decompression for Hemifacial Spasm Associated with Vertebrobasilar Artery

OBJECTIVE: Hemifacial spasm (HFS) is considered as a reversible pathophysiological condition mainly induced by continuous vascular compression of the facial nerve root exit zone (REZ) at the cerebellopontine angle. As an offending vessel, vertebrobasilar artery tends to compress much more heavily than others. The authors analyzed HFS caused by vertebrobasilar artery and described the relationships between microsurgical findings and clinical courses. METHODS: Out of 1,798 cases treated with microvascular decompression (MVD) from Jan. 1980 to Dec. 2004, the causative vessels were either vertebral artery or basilar artery in 87 patients. Seventy-nine patients were enrolled in this study. Preoperatively, computed tomography (CT) or brain magnetic resonance (MR) imaging with 3-dimentional short range MR technique was performed and CT was checked immediately or 2-3 days after anesthetic recovery. The authors retrospectively analyzed the clinical features, the compression patterns of the vessels at the time of surgery and treatment outcomes. RESULTS: There were 47 were male and 32 female patients. HFS developed on the left side in 52 cases and on the right side in 27. The mean age of onset was 52.3 years (range 19-60) and the mean duration of symptoms was 10.7 years. Many patients (39 cases; 49.1%) had past history of hypertension. HFS caused only by the vertebral artery was 8 cases although most of the other cases were caused by vertebral artery (VA) in combination with its branching arteries. Most frequently, the VA and the posterior inferior cerebellar artery (PICA) were the simultaneous causative blood vessels comprising 32 cases (40.5%), and in 27 cases (34.2%) the VA and the anterior inferior cerebellar artery (AICA) were the offenders. Facial symptoms disappeared in 61 cases (77.2%) immediately after the operation and 68 cases (86.1%) showed good outcome after 6 months. Surgical outcome just after the operation was poor in whom the perforators arose from the offending vessels concurrently (p<0.05). CONCLUSION: In case where the vertebral artery is a cause of HFS, commonly branching arteries associated with main arterial compression on facial REZ requires more definite treatment for proper decompression because of its relatively poor results compared to the condition caused by other vascular compressive origins.

Neuroprotective Effect of N-nitro-L-arginine Methylester Pretreatment on the Early Stage of Kainic Acid Induced Neuronal Degeneration in the Rat Brain

OBJECTIVE: Kainic acid(KA) enhances the expression of nitric oxide synthase, increases nitric oxide(NO), and thus evokes epileptic convulsion, which results in neuronal damage in the rat brain. NO may stimulate cyclooxygenase type-2 (COX-2) activity, thus producing seizure and neuronal injury, but it has also been reported that KA-induced seizure and neurodegeneration are aggravated on decreasing the COX-2 level. This study was undertaken to investigate whether the suppression of NO using the NOS inhibitor, N-nitro-L-arginine methyl ester(L-NAME), suppresses or enhances the activity of COX-2. METHODS: Silver impregnation and COX-2 immunohistochemical staining were used to localize related pathophysiological processes in the rat forebrain following KA-induced epileptic convulsion and L-NAME pretreatment. Post-injection survival of the rat was 1, 2, 3days and 2months, respectively. RESULTS: After the systemic administration of KA in rats, neurodegeneration increased with time in the cornu ammonis (CA) 3, CA 1 and amygdala, as confirmed by silver impregnation. On pretreating L-NAME, KA-induced neuronal degeneration decreased. COX-2 enzyme activities increased after KA injection in the dentate gyrus, CA 3, CA 1, amygdala and pyriform cortex, as determined by COX-2 staining. L-NAME pretreatment prior to KA-injection, caused COX-2 activities to increase compared with KA- injection only group by 1day and 2days survival time point. CONCLUSION: These results suggest that L-NAME has a neuroprotective effect on KA-induced neuronal damage, especially during the early stage of neurodegeneration.

Clinical Analysis of the Aneurysm of Proximal(A1) Segment of Anterior Cerebral Artery / 대한뇌혈관외과학회지

OBJECTIVES: Aneurysms of the anterior cerebral circulation are usually found on the anterior communicating artery (ACoA) or peripheral portion (A2) of the anterior cerebral artery (ACA). Infrequently, they are found on proximal segment (A1) of the ACA. These are presented 0.88-2.1% of all intracranial aneurysm cases. There are few describing a series of patient with A1 aneurysms. In this report, we present our surgical experience of the 27 A1 aneurysms. MATERIAL AND METHODS: 27 patients with aneurysm of proximal segment of anterior cerebral artery were operated on between January 1983 and September 2004. Retrospective analysis of clinical characteristics, radiologic findings, operation method, clinical outcomes and complications were performed. RESULTS: 27 patients with aneurysm of proximal segment of anterior cerebral artery, male was 11 cases, female was 16 cases. Relatively, predominantly occurred in female. In preoperative Hunt-Hess grade (H-H grade) of the patient, H-H grade I was 10, gradeII in 13, grade III in 3, grade IV in 1 case. In CT findings, 23 cases presented only SAH, SAH and ICH in 4, accompanying hydrocephalus in 3 cases. In angiographics and surgical findings, according to aneurysm site, proximal type was 9 cases, middle type in 8, distal type in 10 cases, and compared with each clinical outcomes. In 9 patients, aneurysms was found in right side and 7 patients of these had favorable outcomes. In left side, 12 of 18 patients had favorable outcomes. Postoperative complication occurred in 8 cases, postoperative infarction in 3 case. vasospasm in 4 cases, hydrocephalus, meningitis in 4 cases. 5 patients had multiple aneurysms. In 2 cases of these, A1 aneurysm was ruptured. In 3 cases, other aneurysm was ruptured and A1 aneurysm was incidental finding. In total 27 patients, 19 patients had favorable outcomes and unfavorable outcomes in 8. CONCLUSION: Aneurysms of proximal segment (A1) of the anterior cerebral artery occur very infrequently and in this report, These are presented 3.9% (27 out of 680) in anterior cerebral artery aneurysms. 19 patients underwent direct surgery had good outcomes after the surgery. As causes of unfavorable outcomes, poor preoperative general condition, injury of perforating artery during operation and vasospasm. Comparison with other aneurysms, relative good outcomes can be obtained by direct surgery.

Clinical Analysis of the Aneurysm of Proximal(A1) Segment of Anterior Cerebral Artery / 대한뇌혈관외과학회지

OBJECTIVES: Aneurysms of the anterior cerebral circulation are usually found on the anterior communicating artery (ACoA) or peripheral portion (A2) of the anterior cerebral artery (ACA). Infrequently, they are found on proximal segment (A1) of the ACA. These are presented 0.88-2.1% of all intracranial aneurysm cases. There are few describing a series of patient with A1 aneurysms. In this report, we present our surgical experience of the 27 A1 aneurysms. MATERIAL AND METHODS: 27 patients with aneurysm of proximal segment of anterior cerebral artery were operated on between January 1983 and September 2004. Retrospective analysis of clinical characteristics, radiologic findings, operation method, clinical outcomes and complications were performed. RESULTS: 27 patients with aneurysm of proximal segment of anterior cerebral artery, male was 11 cases, female was 16 cases. Relatively, predominantly occurred in female. In preoperative Hunt-Hess grade (H-H grade) of the patient, H-H grade I was 10, gradeII in 13, grade III in 3, grade IV in 1 case. In CT findings, 23 cases presented only SAH, SAH and ICH in 4, accompanying hydrocephalus in 3 cases. In angiographics and surgical findings, according to aneurysm site, proximal type was 9 cases, middle type in 8, distal type in 10 cases, and compared with each clinical outcomes. In 9 patients, aneurysms was found in right side and 7 patients of these had favorable outcomes. In left side, 12 of 18 patients had favorable outcomes. Postoperative complication occurred in 8 cases, postoperative infarction in 3 case. vasospasm in 4 cases, hydrocephalus, meningitis in 4 cases. 5 patients had multiple aneurysms. In 2 cases of these, A1 aneurysm was ruptured. In 3 cases, other aneurysm was ruptured and A1 aneurysm was incidental finding. In total 27 patients, 19 patients had favorable outcomes and unfavorable outcomes in 8. CONCLUSION: Aneurysms of proximal segment (A1) of the anterior cerebral artery occur very infrequently and in this report, These are presented 3.9% (27 out of 680) in anterior cerebral artery aneurysms. 19 patients underwent direct surgery had good outcomes after the surgery. As causes of unfavorable outcomes, poor preoperative general condition, injury of perforating artery during operation and vasospasm. Comparison with other aneurysms, relative good outcomes can be obtained by direct surgery.

Gamma Knife Radiosurgery for Growth Hormone-secreting Pituitary Adenoma following Trans-sphenoidal Approach

OBJECTIVE: The results of gamma knife radiosurgery(GKRS) for growth hormone(GH)-secreting pituitary adenoma are investigated to identify the role of adjuvant GKRS for remnant or recurrent tumor following transsphenoidal approach(TSA). METHODS: From March 1992 to December 2001, 20 patients treated by GKRS for GH-secreting pituitary adenoma following TSA were followed up more than 3 years and evaluated their symptomatic, hormonal and radiological changes after radiosurgery. RESULTS: There were 6 men and 14 women and the mean age was 40.2 years (range 24-58 years). The maximal dose was 32 to 60Gy (mean 46.2Gy) and the marginal dose was 12.8 to 36Gy (mean 25.5Gy). The mean follow-up time was 5.9 years (range 3-10years). Normalization of GH level (below 2ng/ml) was achieved in 10 of 20 patients (50.0%), and the normalization of IGF-I was in 8 of 15 patients (53.3%). On follow up MR imaging, the tumor control rate was 100% and the tumor volume reduction rate was 25~50% in 4 patients, 50~75% in 13 patients and 75~100% in 3 patients. CONCLUSION: In the treatment of GH-secreting pituitary adenoma, tumor control rate and improvement of clinical symptom show good outcome without major complication after adjuvant GKRS following TSA, though the rate of normalization of GH level is unsatisfactory. The optimal marginal dose for GH-secreting pituitary adenoma is more than 25Gy, and secondary GKRS can be considered in the failed cases to achieve effective hormonal normalization after the first adjuvant GKRS.

Preliminary Experiences with Interbody Titanium Cage(RABEA(TM)) Fusion in Patients with Degenerative Cervical Disease

OBJECTIVE: The purpose of this study is to evaluate the safety and efficacy of cervical interbody fusion with implantable titanium cage(RABEA(TM)). The authors retrospectively analysis the result of application of cervical hollow cage(RABEA(TM)) without bone graft to the patients of degenerative cervical disease. METHODS: 78 patients with radiculopathy with or without myelopathy due to degenerative cervical diseases were underwent anterior cervical discectomy and interbody fusion with titanium cages(RABEA(TM)) which were not filled with autogenous bone from June 1999 to December 2002. Among them, 33 patients could be followed-up for at least 6 months. Mean follow-up period was 13.3 months(ranged 6-30 months). RESULTS: Good or excellent results were found in approximately 82.0%. Preoperatively, the mean height of the disc space was 4.27mm(range 3~6mm), and at 1 day postoperatively it was 7.87mm(range 7~9mm). The mean height of the disc space after 1 year was 6.07mm(range 1~8mm). Due to subsidence of cage, 7 patients showed decrease of disc space height to preoperative disc space height. Among them, 1 patients showed poor results. A solid fusion was achieved in all patients. In this context, causes of subsidence are represented by osteoporosis and degree of cage recess. CONCLUSION: Titanium cages appear safe and effective in the treatment of degenerative cervical disease. But subsidence of cage, so far limited in number, appeared to be important risk factor for recurrence of the symptoms.

Post-treatment Bleeding of Cerebral Arteriovenous Malformations after Gamma Knife Radiosurgery

OBJECTIVE: This study is designed to assess the cause of post-treatment bleeding after gamma knife radiosurgery(GKRS) for cerebral arteriovenous malformation(AVM). METHODS: We experienced post-treatment bleeding in seven cases out of 214 AVM patients group before complete obliteration and analyzed their clinical characteristics, angiographic architecture and radiosurgical dosimetry. RESULTS: Hemorrhage rate was 3.2% (7/214) and the bleeding occurred individually at 4, 8, 9, 20, 44, 44 and 115 months after GKRS. Annual bleeding rate was 0.6% (7 episodes of bleeding / 1131 patient years). Three patients presented with hemorrhage as initial symptom upon admission and four patients were admitted with other symptom rather than hemorrhage. AVM was deep-seated in 4 cases, and at motor cortex in three patients. Average marginal dose was 18.9Gy (range;10-25Gy). Most of patients showed angiographic risk factor for bleeding such as venous aneurysm, multiple venous drainage, dual arterial supply and shunt type. Upon bleeding incidence, emergency operation was performed in 5 cases and two patients received second GKRS. Two patients were expired after emergency operation. CONCLUSION: The risk of hemorrhage from GKRS for AVMs is inevitable, even if patients are in non-hemorrhagic group before complete obliteration. In order to minimize hemorrhage rate, intensive follow-up is strongly suggested after radiosurgery, and the retreatment for a residual nidus is recommended at early point after the latency period.

Gamma Knife Radiosurgery for Hemorrhagic Cavernous Malformations

OBJECTIVE: In patients with hemorrhagic cavernous malformation(CMs) located in critical brain region that were thought to pose an excessive risk for microsurgical resection, Gamma Knife radiosurgery(GKRS) has been used as an alternative management option for these lesions. The purpose of this study is to evaluate the efficacy of GKRS for hemorrhagic CMs. METHODS: Among the patients of hemorrhagic CMs who had been treated by using Leksell Gamma Knife, 20 patients who had been followed up more than 2 years were analysed for their postradiosurgical results. RESULTS: Mean target volume was 3199mm3(224-9300mm3). Mean maximal dose was 28.9Gy(15-50Gy) and mean marginal dose was 16.5Gy(9-25Gy). 50% isodose or greater was used for the margins of the lesions. Mean follow-up period after GKRS was 51 months(24-112months). During the follow-up period, 3 patients suffered from rebleeding at 5, 6, and 28 months after radiosurgery, respectively. Two cases had a rebleeding in latency period(time interval from GKRS to its maximal effect on vascular obliteration, usually 2-4 years in case of CMs) and another one case after latency period. The annual rebleeding rate was 3.1%(first 2 years after radiosurgery 5%, thereafter 1.7%). Delayed radiation-induced complications occurred in 4 cases at 4, 7, 15 and 18 months after radiosurgery. CONCLUSION: The use of GKRS as an alternative management strategy to the hemorrhagic CMs which located in critical brain region and so had potential risk for microsurgical resection is thought to be available. And the GKRS would reduce the rate of rebleeding of CMs, especially after 2-3 years of latency periods.