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Hidetoshi Ikeda, Hidefumi Jokura and Takashi Yoshimoto

Object. The results of combined transsphenoidal surgery and adjuvant gamma knife surgery (GKS) for growth hormone (GH)—secreting adenoma were investigated using biochemical cure criteria for surgery and biological cure criteria for adjuvant GKS.

Methods. Ninety patients (42 male and 48 female patients), ranging from 11 to 75 years of age, underwent transsphenoidal surgery for GH-secreting pituitary adenoma. Preoperative and postoperative GH and insulin-like growth factor-I levels were measured, as was the postoperative GH level after the oral glucose tolerance test. Tumor size, cavernous sinus (CS) invasion, and residual tumor were evaluated using magnetic resonance (MR) imaging. Transsphenoidal microsurgery was performed, followed by adjuvant GKS when there was persistent biochemical evidence of GH hypersecretion with residual tumor detectable in the CS on MR imaging. Patients in whom GKS was contraindicated were treated with conventional radiotherapy or by medical means.

Conclusions. The overall surgical cure rate was 57% based on recently accepted biochemical cure criteria. Patients with no CS invasion achieved a 100% cure rate, whereas patients with CS invasion achieved an 82% cure rate (14 of 17 patients) after adjuvant GKS. The combination of transsphenoidal microsurgery and adjuvant GKS is the optimal therapy for patients with GH-secreting adenoma.

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Toshiki Endo, Toshiyuki Takahashi, Hidefumi Jokura and Teiji Tominaga

Object

Spinal intradural arachnoid cysts are a rare cause of spinal cord compression. Since 2000, the authors have treated patients using 2- or 3-level hemilaminectomy or laminectomy followed by partial cyst wall resection as well as endoscopic inspection and fenestration of the cyst wall. They evaluated the usefulness and reliability of endoscopic treatment for this clinical entity based on long-term follow-up results.

Methods

Between 1997 and 2003, 11 patients (3 males and 8 females) with spinal intradural arachnoid cysts were treated, and the authors conducted a retrospective review of these cases. Before 2000, 5 patients were surgically treated without the use of endoscopic techniques. During that time, more than 4 levels of hemilaminectomy were performed to expose and remove cyst walls that extended longitudinally over the spinal axis. Beginning in 2000, endoscopy was used in all 6 cases. Up to 3 levels of hemilaminectomy or 2 levels of laminectomy were performed, and the cyst wall was resected through the bone window. An endoscope was inserted into the cyst cavity and moved in the cranial and caudal direction to fenestrate the cyst wall, resulting in communication of the cyst cavity with the subarachnoid space.

Results

Postoperatively, the neurological symptoms of all patients improved. During long-term follow-up (mean 114.8 months), none of the patients treated with or without endoscopy experienced recurrent cyst formation.

Conclusions

Endoscopic techniques allow neurosurgeons to treat spinal intradural arachnoid cysts less invasively than with standard surgical approaches. Although the number of cases reviewed in this report is small, the data suggest that the use of endoscopy can be an important option in the surgical treatment of spinal arachnoid cysts.

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Jonathan P. S. Knisely, Masaaki Yamamoto, Cary P. Gross, William A. Castrucci, Hidefumi Jokura and Veronica L. S. Chiang

Object

Oligometastatic brain metastases may be treated with stereotactic radiosurgery (SRS) alone, but no consensus exists as to when SRS alone would be appropriate. A survey was conducted at 2 radiosurgery meetings to determine which factors SRS practitioners emphasize in recommending SRS alone, and what physician characteristics are associated with recommending SRS alone for ≥ 5 metastases.

Methods

All physicians attending the 8th Biennial Congress and Exhibition of the International Stereotactic Radiosurgery Society in June 2007 and the 18th Annual Meeting of the Japanese Society of Stereotactic Radiosurgery in July 2009 were asked to complete a questionnaire ranking 14 clinical factors on a 5-point Likert-type scale (ranging from 1 = not important to 5 = very important) to determine how much each factor might influence a decision to recommend SRS alone for brain metastases. Results were condensed into a single dichotomous outcome variable of “influential” (4–5) versus “not influential” (1–3). Respondents were also asked to complete the statement: “In general, a reasonable number of brain metastases treatable by SRS alone would be, at most, ___.” The characteristics of physicians willing to recommend SRS alone for ≥ 5 metastases were assessed. Chi-square was used for univariate analysis, and logistic regression for multivariate analysis.

Results

The final study sample included 95 Gamma Knife and LINAC-using respondents (54% Gamma Knife users) in San Francisco and 54 in Sendai (48% Gamma Knife users). More than 70% at each meeting had ≥ 5 years experience with SRS. Sixty-five percent in San Francisco and 83% in Sendai treated ≥ 30 cases annually with SRS. The highest number of metastases considered reasonable to treat with SRS alone in both surveys was 50. In San Francisco, the mean and median numbers of metastases considered reasonable to treat with SRS alone were 6.7 and 5, while in Sendai they were 11 and 10. In the San Francisco sample, the clinical factors identified to be most influential in decision making were Karnofsky Performance Scale score (78%), presence/absence of mass effect (76%), and systemic disease control (63%). In Sendai, the most influential factors were the size of the metastases (78%), the Karnofsky Performance Scale score (70%), and metastasis location (68%). In San Francisco, 55% of respondents considered treating ≥ 5 metastases and 22% considered treating ≥ 10 metastases “reasonable.” In Sendai, 83% of respondents considered treating ≥ 5 metastases and 57% considered treating ≥ 10 metastases “reasonable.” In both groups, private practitioners, neurosurgeons, and Gamma Knife users were statistically significantly more likely to treat ≥ 5 metastases with SRS alone.

Conclusions

Although there is no clear consensus for how many metastases are reasonable to treat with SRS alone, more than half of the radiosurgeons at 2 international meetings were willing to extend the use of SRS as an initial treatment for ≥ 5 brain metastases. Given the substantial variation in clinicians' approaches to SRS use, further research is required to identify patient characteristics associated with optimal SRS outcomes.

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Masaaki Yamamoto, Yoshihisa Kida, Seiji Fukuoka, Yoshiyasu Iwai, Hidefumi Jokura, Atsuya Akabane and Toru Serizawa

Object

Gamma Knife radiosurgery (GKS) is currently used for primary or postoperative management of cavernous sinus (CS) hemangiomas. The authors describe their experience with 30 cases of CS hemangioma successfully managed with GKS.

Methods

Thirty patients with CS hemangiomas, including 19 female and 11 male patients with a mean age of 53 years (range 19–78 years) underwent GKS at 7 facilities in Japan. Pathological entity was confirmed using surgical specimens in 17 patients, and neuroimaging diagnosis only in 13. Eight patients were asymptomatic before GKS, while 22 had ocular movement disturbances and/or optic nerve impairments. The mean tumor volume was 11.5 cm3 (range 1.5–51.4 cm3). The mean dose to the tumor periphery was 13.8 Gy (range 10.0–17.0 Gy).

Results

The mean follow-up period was 53 months (range 12–138 months). Among the 22 patients with symptoms prior to GKS, complete remission was achieved in 2, improvement in 13, and no change in 7. Hemifacial sensory disturbance developed following GKS in 1 patient. The most recent MR images showed remarkable shrinkage in 18, shrinkage in 11, and no change in 1 patient.

Conclusions

Gamma Knife radiosurgery proved to be an effective treatment strategy for managing CS hemangiomas. Given the diagnostic accuracy of recently developed neuroimaging techniques and the potentially serious bleeding associated with biopsy sampling or attempted surgical removal, the authors recommend that GKS be the primary treatment in most patients who have a clear neuroimaging diagnosis of this condition.

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Yousuke Akamatsu, Takayuki Sugawara, Shigeki Mikawa, Atsushi Saito, Sadafumi Ono, Kazuo Takayama, Hidefumi Jokura and Hirofumi Seki

A 75-year-old woman underwent Gamma Knife surgery (GKS) for a vestibular schwannoma. Eight years after GKS, she suffered sudden onset of headache. Computed tomography revealed diffuse subarachnoid hemorrhage around the cisterns of the posterior fossa. Right vertebral artery angiography showed an aneurysm arising from the lateral pontomedullary segment of the left anterior inferior cerebellar artery. The aneurysm was not located at a branching site. Trapping of the distal anterior inferior cerebellar artery aneurysm was performed, and the aneurysm was removed. The pathological features of this aneurysm are discussed. This aneurysm was diagnosed as a pseudoaneurysm pathologically. This is the first report of aneurysm formation with pathological findings following GKS for a vestibular schwannoma.

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Bengt Karlsson, Hidefumi Jokura, Masaaki Yamamoto, Michael Söderman and Ingmar Lax

Object

The results of a novel radiosurgical approach to treat large arteriovenous malformations (AVMs) with repeated radiosurgery are presented and discussed.

Methods

The outcome was studied following repeated Gamma Knife surgery (GKS) for large AVMs, defined as a nidus volume of 9 ml or more. The philosophy was to treat the whole AVM with a low dose of radiation (≥ 10 Gy), and to repeat the treatment if the AVM shrank but was not obliterated. The study included 133 patients with AVMs treated at one of three different institutions. Clinical information was available for all patients, and complete radiological follow-up was available in 89 patients after the first treatment, and in 19 after the second treatment.

Results

The estimated obliteration rate following repeated GKS was 62%. Four patients (3%) developed neurological deficits caused by the radiation, whereas five others (4%) developed cystic changes. The annual incidence of hemorrhage was high (7%), of which 35% occurred within the 1st year after the first treatment.

Conclusions

Repeated radiosurgery seems to be a viable option for some AVMs considered to be too large for conventional radiosurgical treatment. The incidence of posttreatment hemorrhages seems to be a larger clinical problem than radiation-induced complications.

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Ryuta Saito, Toshihiro Kumabe, Mika Watanabe, Hidefumi Jokura, Makoto Shibuya, Yoichi Nakazato and Teiji Tominaga

✓The authors report on a 21-year-old man who presented with a low-grade fibromyxoid sarcoma primarily located in the right parietal lobe with diffuse infiltration. The low-grade fibromyxoid sarcoma is a rare sarcoma of the deep soft tissue that is characterized as an indolent but metastasizing soft-tissue neoplasm with a deceptively benign histological appearance. Only one case of intracranial origin has been previously reported in the literature. A high rate of local recurrence and eventual metastasis has been demonstrated for this tumor in deep soft tissue. Similarly, the patient in the present case suffered recurrence 6 times; he underwent treatment by surgical removal 4 times, Gamma Knife surgery twice, and local radiation therapy once during the 7-year follow-up period. The tumor is still under control without any evidence of extracranial metastasis. To the authors' knowledge, this is the first case report that discusses the clinical course of this rare disease in detail.

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Kenichi Sato, Hidefumi Jokura, Reizo Shirane, Tetsuya Akabane, Hiroshi Karibe and Takashi Yoshimoto

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Bengt Karlsson, Ingmar Lax, Masaaki Yamamoto, Michael Söderman, Hidefumi Jokura, Charles Rosen and Julian Bailes

Object

The authors sought to assess the relationship between obliteration rate and different dose parameters following fractionated radiotherapy for arteriovenous malformations (AVMs). A comparison of the results of radiosurgery and radiotherapy for AVMs was made to calculate the best fit α/β value, which would then be used as a model for predicting the treatment outcome, independent of the number of fractions applied.

Methods

Data from 1453 patients were analyzed: 1154 treated with radiosurgery and 300 with fractionated radiotherapy. The relationships between dose and obliteration rate after 3 years were calculated, and the best fit curve to the empirical results was defined. The higher the dose per fraction, biologically effective dose, and the lower the total dose, the higher the obliteration rate. The isoeffective doses when comparing radiotherapy and radiosurgery independent of the α/β value could not be defined. The dose per fraction had the best predictive value, independent of the number of fractions.

Conclusions

Dose per fraction seems to be the decisive parameter for the treatment response following both radiotherapy and radiosurgery. A larger number of fractions did not increase the obliteration rate. The data indicate that higher doses per fraction should be used when irradiating AVMs.

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Reizo Shirane, Ching-chan Su, Yasuko Kusaka, Hidefumi Jokura and Takashi Yoshimoto

Object. Craniopharyngiomas frequently grow from remnants of the Rathke pouch, which is located on the cisternal surface of the hypothalamic region. These lesions can also extend elsewhere in the infundibulohypophyseal axis. The aim of this study was to establish the usefulness of the frontobasal approach made through a relatively small craniotomy window for the removal of tumors protruding from the sellar—suprasellar region into the third and basal cistern.

Methods. Thirty-one patients who were surgically treated for craniopharyngiomas extending outside the sellar—suprasellar region were evaluated. The diagnoses were established in all cases by using magnetic resonance and computerized tomography imaging. The initial symptoms and signs were increased intracranial pressure in eight, vision impairment or visual field defect in 16, hypopituitarism in 17, and psychological disturbances in three cases. All patients underwent surgery via the frontobasal interhemispheric approach, and the average follow-up period was 30 months.

Total removal of the lesion was achieved in 22 cases, six patients underwent subtotal resection, and three underwent partial removal due to tumor recurrence after previous surgeries performed with or without adjunctive radiotherapy. Major complications, including impairment of the cranial nerves, were not observed in the immediate postoperative period. One patient exhibited transient memory disturbance due to infarction of the perforating vessels; after 3 months this symptom was ameliorated. None of the patients died during long-term follow up; however, four of the 22 who underwent total removal and six of the nine patients who underwent subtotal or partial removal suffered recurrence. Of the 10 patients with recurrence, six experienced a small recurrence of the lesion (average 3 months postsurgery); after gamma knife surgery (GKS), the size of two of the lesions was unchanged and in four reoperation was performed due to tumor enlargement during the follow-up period. Ultimately, a total of eight patients (four with recurrence and four who had been treated with GKS) underwent reoperation, with gross-total removal via the same approach or combined with the orbitozygomatic approach in patients with very short optic nerves. In no patient was deterioration of visual acuity and visual field observed after surgery. Although all patients except four children and one adult were receiving some form of hormone replacement therapy, their endocrine status was stably controllable.

Conclusions. In the authors' experience, the frontobasal interhemispheric approach, even made through a small craniotomy window, is a valid choice for the removal of craniopharyngiomas extending outside the sellar—suprasellar region. Via this approach, tumors can be removed without significant sequelae related to the surgical method, due to ease of preservation of the pituitary stalk, hypothalamic structures, and perforating vessels. This approach offers a safe and minimally invasive means of treating craniopharyngiomas.