Takakazu Kawamata

Endoscopic augmented reality navigation system for endonasal transsphenoidal surgery to treat pituitary tumors: technical note.

OBJECTIVE Endoscopes have been commonly used in transsphenoidal surgery to treat pituitary tumors, to compensate for the narrow surgical field. Although many navigation systems have been introduced for neurosurgical procedures, there have been few reports of navigation systems for endoscopic operations. This report presents our recently developed, endoscopic, augmented reality (AR) navigation system. METHODS The technology is based on the principles of AR environment technology. The system consisted of a rigid endoscope with light-emitting diodes, an optical tracking system, and a controller. The operation of the optical tracking system was based on two sets of infrared light-emitting diodes, which measured the position and orientation of the endoscope relative to the patient’s head. We used the system during endonasal transsphenoidal operations to treat pituitary tumors in 12 recent cases. RESULTS Anatomic, “real,” three-dimensional, virtual images of the tumor and nearby anatomic structures (including the internal carotid arteries, sphenoid sinuses, and optic nerves) were superimposed on real- time endoscopic live images. The system also indicated the positions and directions of the endoscope and the endoscopic beam in three-dimensional magnetic resonance imaging or computed tomographic planes. Furthermore, the colors of the wire-frame images of the tumor changed according to the distance between the tip of the endoscope and the tumor. These features were superior to those of conventional navigation systems, which are available only for operating microscopes. CONCLUSION The endoscopic AR navigation system allows surgeons to perform accurate, safe, endoscope-assisted operations to treat pituitary tumors; it is particularly useful for reoperations, in which midline landmarks may be absent. We consider the AR navigation system to be a promising tool for safe, minimally invasive, endonasal, transsphenoidal surgery to treat pituitary tumors.

Management of intracranial hemorrhage associated with anticoagulant therapy

BACKGROUNDnIntracranial hemorrhage may be a particularly devastating complication of anticoagulant therapy. Very few accounts have reported data on the duration of anticoagulant discontinuation following intracranial hemorrhage or the intensity of anticoagulation during treatment for it, although we must adequately manage such a complication.nnnMETHODSnWe analyzed the management of warfarin-related intracranial hemorrhages in 27 patients with cardiac diseases. We evaluated the degree of anticoagulation using the thrombotest. Anticoagulants were stopped as soon as the diagnosis of intracranial hemorrhage was established by computed tomographic scan.nnnRESULTSnMechanical valve prosthesis patients, who required intensive long-term anticoagulant therapy, constituted the majority of our series (74.1%). Intraoperative hemostasis was brought under control despite low thrombotest values (13%-68%) at the time of surgery except for the acute subdural hematoma (SDH) patients with cerebral contusion. Early resumption of anticoagulant therapy (within 3 days) did not cause intracranial rebleeding in any operative patient. All the chronic SDH patients and some of the subcortical hematoma patients had a good outcome. All three patients with acute SDH and contusion, however, had a fatal outcome because of intracranial rebleeding within a short period of time or ineffective intraoperative hemostasis.nnnCONCLUSIONSnThe patients with anticoagulant-related intracranial hemorrhage may undergo surgery with thrombotest values approximately between 20% and 60%, and anticoagulants can be resumed after an interval of 3 days. Aggressive surgery should particularly be performed in patients with anticoagulation-related chronic SDH or subcortical hemorrhage, as in the cases of anticoagulant-unrelated intracranial hemorrhage.

Individualized High-Dose Cabergoline Therapy for Hyperprolactinemic Infertility in Women with Micro- and Macroprolactinomas

CONTEXTnCabergoline is effective for hyperprolactinemic hypogonadism. However, the rate of cabergoline-induced pregnancy in women with prolactinoma remains unknown. Also unknown is whether cabergoline can control tumor growth and thereby achieve successful pregnancy in patients with macroprolactinomas.nnnMETHODSnEighty-five women with macroprolactinomas (n = 29) or microprolactinomas (n = 56) received prospective, high-dose cabergoline therapy for infertility based on individual prolactin suppression and/or tumor shrinkage. The patients included 31 bromocriptine-resistant, 32 bromocriptine-intolerant, and 22 previously untreated women. Conception was withheld until three regular cycles returned in women with microadenoma and until tumors shrank below 1.0 cm in height in women with macroadenoma. Cabergoline was withdrawn at the fourth gestational week.nnnRESULTSnCabergoline normalized hyperprolactinemia and recovered the ovulatory cycle in all patients. All adenomas contracted, and 11 macroadenomas and 29 microadenomas disappeared. Eighty patients (94%) conceived 95 pregnancies, two of which were cabergoline-free second pregnancies. The dose of cabergoline at the first pregnancy was 0.25-9 mg/wk overall and 2-9 mg/wk in the resistant patients. Of the 93 pregnancies achieved on cabergoline, 86 resulted in 83 single live births, one stillbirth, and two abortions; the remaining seven were ongoing. All babies were born healthy, without any malformations. No mothers experienced impaired vision or headache suggestive of abnormal tumor reexpansion throughout pregnancy.nnnCONCLUSIONnCabergoline achieved a high pregnancy rate with uneventful outcomes in infertile women with prolactinoma, independent of tumor size and bromocriptine resistance or intolerance. Cabergoline monotherapy could substitute for the conventional combination therapy of pregestational surgery or irradiation plus bromocriptine in macroprolactinomas.

DNA Mismatch Repair Protein (MSH6) Correlated With the Responses of Atypical Pituitary Adenomas and Pituitary Carcinomas to Temozolomide: The National Cooperative Study by the Japan Society for Hypothalamic and Pituitary Tumors

CONTEXTnTemozolomide (TMZ) is an alkylating agent and was a first-line chemotherapeutic agent for malignant gliomas. Recently, TMZ has been documented to be effective against atypical pituitary adenomas (APAs) and pituitary carcinomas (PCs).nnnOBJECTIVEnThe clinical and pathological characteristics of APAs and PCs treated with TMZ in Japan were surveyed and analyzed retrospectively.nnnDESIGNnMembers of the Japan Society of Hypothalamic and Pituitary Tumors were surveyed regarding the clinical characteristics of APAs and PCs treated with TMZ. Stored tumor samples were gathered from the responders and were assessed by the immunohistochemistry of Ki-67, O(6)-methyl-guanine-DNA methyltransferase, p53, MSH6, and anterior pituitary hormones. Responses to TMZ treatment were defined as complete response (CR), partial response (PR), progressive disease (PD), and stable disease (SD) according to RECIST (Response Evaluation Criteria in Solid Tumors) version 2.0.nnnSUBJECTSnThree samples from 3 subjects with APA and 11 samples from 10 subjects with PC were available.nnnRESULTSnThe 13 subjects had APAs and PCs consisting of 5 prolactin-producing tumors, 5 ACTH-producing tumors, and 3 null cell adenomas. The clinical response to TMZ treatment was as follows: 4 cases of CR and PR (31%), 2 cases of SD (15%), 6 cases of recurrence after CR and PR (46%), and 1 case of PD (8%). However, considerable subjects had recurrent disease after a response to TMZ. The immunohistochemical findings of Ki-67, O(6)-methyl-guanine-DNA methyltransferase, and p53 did not show any significant correlation with the efficacy of TMZ. However, the immunopositivity of MSH6 was positively correlated with TMZ response (P = .015, Fishers exact test).nnnCONCLUSIONSnThis study showed that preserving MSH6 function was contributory to the effectiveness of TMZ in malignant pituitary neoplasms. It is necessary to survey more cases and evaluate multifactor analyses.

Hyponatremia after Transsphenoidal Surgery for Hypothalamo-Pituitary Tumors

Transient diabetes insipidus is a well-known complication after transsphenoidal surgery (TSS). On the other hand, transient hyponatremia has been reported as being a delayed complication of TSS. Transient hyponatremia has been attributed to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), but the details of hyponatremia have not been clarified. In the present study, we retrospectively reviewed 110 consecutive patients (39 males and 71 females, age 9–80 years) operated on transsphenoidally for pituitary and hypothalamic tumors. We investigated the frequency, time of onset, duration of hyponatremia after TSS, and analyzed possible factors associated with it. A postoperative sodium concentration <135 mEq/l was observed in 29 (26%) patients. Five patients were excluded from this study because their hyponatremia could be due to either overdose of desmopressin or SIADH for meningitis. Therefore, we investigated 24 (22%) patients with hyponatremia in this study. The sodium levels in the patients with hyponatremia ranged from 110 to 134, with a mean of 126.2 ± 5.3 mEq/l. Hyponatremia was observed on average on postoperative day 9.5 ± 2.4, the serum sodium levels normalized within 3.8 ± 1.7 days. Hyponatremia occurred in patients with non-functioning pituitary adenoma (26%, 11/42), Rathke’s cleft cyst (29%, 5/17), prolactinoma (31%, 4/13) and acromegaly (15%, 4/27). 18 patients (75%, 6/24) who developed hyponatremia had macrotumor (>10 mm), and 6 patients (25%, 6/24) had microtumor. The plasma arginine vasopressin (AVP) levels in the patients with hyponatremia ranged from 0.21 to 2.1, with a mean of 0.79 ± 0.46 pg/ml, and the levels were inversely correlated with plasma osmolality (r = –0.80, p = 0.002). The urine to plasma osmolality ratios were >1. All the patients received appropriate hormonal replacement, including hydrocortisone. These data showed that postoperative hyponatremia after TSS was not rare, and the hyponatremia was mainly associated with SIADH. As the hyponatremia could be a life-threatening complication, all patients should be screened for serum electrolytes after TSS.

Gamma Knife Radiosurgery for Meningiomas: Four Cases of Radiation-Induced Edema

We review 48 cases of meningioma treated with Gamma Knife radiosurgery. The mean marginal dose was 15 Gy and the mean follow-up was 12 months. Follow-up computed tomography and magnetic resonance imaging showed tumor shrinkage in 19 cases, central necrosis in 1 case, loss of contrast enhancement in 1 case, and no change in 27 cases. We noted 4 cases of radiation-induced edema in supratentorial meningiomas.

Incidence and predictive factors of cerebral hyperperfusion after extracranial-intracranial bypass for occlusive cerebrovascular diseases.

BACKGROUND: Although many studies of postoperative cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy have been reported, there are few reports related to extracranial-intracranial (EC-IC) bypass for atherosclerotic occlusive cerebrovascular diseases. OBJECTIVE: To examine the incidence of cerebral hyperperfusion and CHS after EC-IC bypass and to investigate predictive factors. METHODS: Fifty consecutive patients undergoing EC-IC bypass for atherosclerotic occlusive cerebrovascular diseases were studied. Immediately after bypass surgery, resting regional cerebral blood flow was determined under continuous sedation, and postoperative hyperperfusion was evaluated according to the definitions as follows: > 50% increase in regional cerebral blood flow compared with the contralateral side (method 1) and > 100% increase in corrected regional cerebral blood flow compared with preoperative values (method 2). Logistic regression analysis was conducted to determine the effect of multiple variables on postoperative hyperperfusion. RESULTS: Transient symptoms of CHS were observed in 3 patients. Cerebral hyperperfusion was detected in 12 patients (24%) as defined by method 1 and in 9 patients (18%) by method 2. Postoperative hyperperfusion occurred significantly more frequently in patients with the steal phenomenon (regional cerebral vasoreactivity ≤ 0%; P = .001 by method 1 and P = .001 by method 2) and correlated with impaired preoperative regional cerebral vasoreactivity (P < .001). Logistic regression analysis revealed that the steal phenomenon was a significant risk factor for hyperperfusion as defined by both methods 1 (P = .009) and 2 (P = .03). CONCLUSION: The incidence of cerebral blood flow-assessed postoperative hyperperfusion after EC-IC bypass for atherosclerotic occlusive cerebrovascular diseases was not rare. Post EC-IC bypass CHS could be reduced by continuous, strict blood pressure control under sedation.

Optimal treatment strategy for craniopharyngiomas based on long-term functional outcomes of recent and past treatment modalities

Although many authors have described treatment strategies for craniopharyngiomas, the optimal treatment of craniopharyngiomas remains controversial. This study aimed to define an adequate surgical strategy for craniopharyngiomas by reviewing the long-term functional performance of patients treated by current and past treatment modalities. Fifty-five patients with longer than 5xa0years of follow-up were selected for the present long-term study. The duration of follow-up ranged from 5.5 to 33xa0years (median, 14.8xa0years). There were 28 adult patients (14 males; median age, 44.4xa0years) and 27 children younger than 16xa0years of age (15 males; median age, 8.1xa0years). The patients were divided into the following treatment groups: single surgery (group A; nu2009=u200914), multiple surgeries (group B; nu2009=u20098), surgery or surgeries followed by radiotherapy (group C; nu2009=u200923), surgery or surgeries (partial removal) followed by radiotherapy + additional treatments (multiple surgeries and/or re-irradiation; group D; nu2009=u200910). In addition to the routine assessments of neurological, endocrine, and visual outcomes, the level of daily functioning was analyzed using the Karnofsky Performance Scale (KPS). Statistical analysis of relationship between KPS score and treatment mode demonstrated that group D had a significantly lower KPS score (Fu2009=u20095.82, pu2009=u20090.0017). Furthermore, mortality, cognitive function, and visual function were significantly better in groups A, B, and C than in group D. Multiple regression analysis demonstrated that cognitive dysfunction, visual disturbance, and treatment mode were independent covariates that significantly affected postoperative KPS score. Adequate primary treatment for craniopharyngiomas is important to avoid subsequent multiple treatments. Craniopharyngiomas should be removed surgically as far as possible but without further deteriorating cognitive and visual functions, either as total resection or subtotal resection with a small remnant that is controllable by radiation therapy.

Rebleeding of intracranial dissecting aneurysm in the vertebral artery following proximal clipping

We describe a case of rebleeding from an intracranial vertebral dissecting aneurysm following proximal clipping. This case suggests that proximal clipping alone may not be an adequate surgical procedure to prevent rebleeding. Surgical treatment of intracranial dissecting aneurysms in the vertebral artery presenting as subarachnoid haemorrhage. (SAH) is discussed.

Possible role of single-voxel 1H-MRS in differential diagnosis of suprasellar tumors

The objective of the present study was investigation of the possible role of proton magnetic resonance spectroscopy (1H-MRS) for differential diagnosis of suprasellar tumors. Forty patients (23 men and 17 women; median age, 45xa0years) with suprasellar, hypothalamic, and third ventricle neoplasms underwent long-echo (TR: 2000xa0ms, TE: 136xa0ms, 128–256 acquisitions) single-voxel 1H-MRS before surgical treatment. The volume of the voxel was either 3.4xa0cc or 8xa0cc. Spectroscopic data were analyzed by calculation of the various metabolite ratios as well as by determination of the type of the pathological 1H-MR spectra. There were 19 pituitary adenomas, 7 gliomas, 5 craniopharyngiomas, 3 chordomas, meningioma, hemangiopericytoma, malignant lymphoma, germinoma, Rathke cleft cyst, and hypothalamic hamartoma (one of each). Six tumors were recurrent after initial surgical resection with or without irradiation. Comparison of the individual metabolite ratios revealed only few subtle differences among neoplasms. In the same time, pattern analysis with determination of the type of the pathological 1H-MR spectra disclosed certain specific characteristics, which seemingly can be used for tumor typing. Meanwhile, metabolic imaging was less effective for characterization of recurrent neoplasms. In conclusion, in cases of initially diagnosed suprasellar tumors with involvement of the hypothalamus and extension into the third ventricle pattern analysis of the single-voxel 1H-MRS can provide valuable information, which, in addition to structural MRI, can be effectively used for diagnostic purposes.