Association of pre- and postoperative αKlotho levels with long-term remission after pituitary surgery for acromegaly.

Soluble αKlotho (sKl) is a disease-specific biomarker that is elevated in patients with acromegaly and declines after surgery for pituitary adenoma. Approximately 25% of patients do not achieve remission after surgery, therefore a risk stratification for patients early in the course of their disease may allow for the identification of patients requiring adjuvant treatment. Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) have been assessed as biomarker for disease activity, however the value of sKl as a predictive biomarker of surgical success has not been evaluated yet. In this study, we measured serum biomarkers before and after transsphenoidal pituitary surgery in 55 treatment-naïve patients. Based on biochemical findings at follow-up (7-16 years), we divided patients into three groups: (A) long-term cure (defined by normal IGF-1 and random low GH (< 1 µg/l) or a suppressed GH nadir (< 0.4/µg/l) on oral glucose testing); (B) initial remission with later disease activity; (C) persistent clinical and/or biochemical disease activity. sKl levels positively related to GH, IGF-1 levels and tumor volume. Interestingly, there was a statistically significant difference in pre- and postoperative levels of sKl between the long-term cure group and the group with persistent disease activity. This study provides first evidence that sKl may serve as an additional marker for surgical success, decreasing substantially in all patients with initial clinical remission while remaining high after surgery in patients with persistent disease activity.

Combining 5-Aminolevulinic Acid Fluorescence and Intraoperative Magnetic Resonance Imaging in Glioblastoma Surgery: A Histology-Based Evaluation.

BACKGROUND: Glioblastoma resection guided by 5-aminolevulinic acid (5-ALA) fluorescence and intraoperative magnetic resonance imaging (iMRI) may improve surgical results and prolong survival. OBJECTIVE: To evaluate 5-ALA fluorescence combined with subsequent low-field iMRI for resection control in glioblastoma surgery. METHODS: Fourteen patients with suspected glioblastoma suitable for complete resection of contrast-enhancing portions were enrolled. The surgery was carried out using 5-ALA-induced fluorescence and frameless navigation. Areas suspicious for tumor underwent biopsy. After complete resection of fluorescent tissue, low-field iMRI was performed. Areas suspicious for tumor remnant underwent biopsy under navigation guidance and were resected. The histological analysis was blinded. RESULTS: In 13 of 14 cases, the diagnosis was glioblastoma multiforme. One lymphoma and 1 case without fluorescence were excluded. In 11 of 12 operations, residual contrast enhancement on iMRI was found after complete resection of 5-ALA fluorescent tissue. In 1 case, the iMRI enhancement was in an eloquent area and did not undergo a biopsy. The 28 biopsies of areas suspicious for tumor on iMRI in the remaining 10 cases showed tumor in 39.3%, infiltration zone in 25%, reactive central nervous system tissue in 32.1%, and normal brain in 3.6%. Ninety-three fluorescent and 24 non-fluorescent tissue samples collected before iMRI contained tumor in 95.7% and 87.5%, respectively. CONCLUSION: 5-ALA fluorescence-guided resection may leave some glioblastoma tissue undetected. MRI might detect areas suspicious for tumor even after complete resection of all fluorescent tissue; however, due to the limited accuracy of iMRI in predicting tumor remnant (64.3%), resection of this tissue has to be considered with caution in eloquent regions.

Growth hormone secreting pituitary microadenomas and empty sella - An under-recognized association?

OBJECTIVE: To describe an association of growth hormone (GH) secreting pituitary microadenomas and empty sella (ES), which has been described in case reports - the underlying mechanisms are unclear. METHODS: We retrospectively analyzed patients operated for GH-producing pituitary adenomas between February 2004 and February 2009. Magnetic resonance imaging (MRI), computed tomography (CT) imaging, and pituitary function testing were performed. All cases underwent transsphenoidal surgery (TSS). Mean follow up was 38 months (range 12-80 months). RESULTS: Out of 152 patients with acromegaly due to GH-producing pituitary adenomas (female:male=73:79; age range 17-63 years), 69 patients had microadenomas (45.4%; 38 females, 31 males). We found 14 cases (14/69, 20.3%), all microadenomas, with presurgical evidence of ES - 10 females (71%) and 4 males (29%) (female:male=2.5:1). When compared with 103 patients with GH-negative microadenomas treated in the same time period (ES in 4 of 103; 3.9%), ES was highly significantly associated with GH production by the microadenoma (p=0.001). In acromegalics with empty sella, no cases of ectopic adenoma were found. Postoperatively, GH and IGF-1 levels fell in all patients, and 7 cases had random GH and IGF-1 levels consistent with cure. CONCLUSION: The combination of GH-producing microadenomas and empty, enlarged sella is not rare. In this setting, preoperative CT scans are very useful and the transsphenoidal approach is efficient and safe. The mechanism underlying the association of GH-producing microadenomas and empty sella remains unclear and requires further studies.

Cervical myelopathy due to chronic overshunting in a pediatric patient: case report and review of the literature.

We present a rare cause of cervical myelopathy produced by an engorged suboccipital epidural venous plexus due to chronic cerebrospinal fluid (CSF) overdrainage. A 17-year-old boy with obstructive hydrocephalus due to a retrocerebellar cyst and secondary implantation of a ventricloperitoneal shunt (VP-shunt) presented with progressive spastic tetraparesis. MRI imaging revealed myelopathy due to significant compression of the cervical spinal cord by engorged epidural veins. Further assessment at a low-pressure setting revealed a broken shunt valve. The VP-shunt valve was changed with an additional anti-siphon device leading to a gradual increase of the intracranial pressure (ICP). After intensive physiotherapy, the patient showed slight clinical improvement. Follow-up imaging within nine days showed distinct regression of the dilated venous plexus at the cranial-cervical junction (CCJ) with the resolution of cord compression. Engorgement of the epidural venous plexus should always be considered in the differential diagnosis of myelopathy in long-term shunt patients even when classical clinical and radiological signs of overshunting are missing.

Ruptured Rathke cleft cyst mimicking pituitary apoplexy.

Rathke cleft cysts (RCCs) are benign cystic lesions of the sellar and suprasellar region that are asymptomatic in most cases. Occasionally, compression of the optic pathway and hypothalamo-pituitary structures may cause clinical symptoms, such as headaches, visual deficits and endocrinopathies. Acute presentation caused by hemorrhage into an RCC have been described in the literature, and the term "Rathke cleft cyst apoplexy" has been coined. We present the case of a 32-year-old man with acute onset of meningitis-type symptoms and imaging findings resembling hemorrhagic pituitary tumor apoplexy. In retrospect, clinical symptoms, intraoperative appearance, and histologic examination were compatible with the diagnosis of nonhemorrhagic rupture of an RCC. Thus, the clinical presentation of "Rathke cleft cyst apoplexy" is not necessarily caused by hemorrhage.

You can't stop the music: reduced auditory alpha power and coupling between auditory and memory regions facilitate the illusory perception of music during noise.

Our brain has the capacity of providing an experience of hearing even in the absence of auditory stimulation. This can be seen as illusory conscious perception. While increasing evidence postulates that conscious perception requires specific brain states that systematically relate to specific patterns of oscillatory activity, the relationship between auditory illusions and oscillatory activity remains mostly unexplained. To investigate this we recorded brain activity with magnetoencephalography and collected intracranial data from epilepsy patients while participants listened to familiar as well as unknown music that was partly replaced by sections of pink noise. We hypothesized that participants have a stronger experience of hearing music throughout noise when the noise sections are embedded in familiar compared to unfamiliar music. This was supported by the behavioral results showing that participants rated the perception of music during noise as stronger when noise was presented in a familiar context. Time-frequency data show that the illusory perception of music is associated with a decrease in auditory alpha power pointing to increased auditory cortex excitability. Furthermore, the right auditory cortex is concurrently synchronized with the medial temporal lobe, putatively mediating memory aspects associated with the music illusion. We thus assume that neuronal activity in the highly excitable auditory cortex is shaped through extensive communication between the auditory cortex and the medial temporal lobe, thereby generating the illusion of hearing music during noise.

Hydrocephalus in 389 patients with aneurysm-associated subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) often leads to hydrocephalus, which is commonly treated by placement of a ventriculoperitoneal (VP) shunt. There is controversy over which factors affect the need for such treatment. In this study, data were prospectively collected from 389 consecutive patients who presented with an aneurysm-associated SAH at a single center. External ventricular drainage placement was performed as part of the treatment for acute hydrocephalus, and VP shunts were placed in patients with chronic hydrocephalus. The data were retrospectively analyzed using two-sample t-tests, Fisher's exact test and logistic regression analysis. Overall, shunt dependency occurred in 91 of the 389 patients (23.4%). Using logistic regression analysis, two factors were found to be significantly associated with VP shunt placement: an initial Glasgow Coma Scale (GCS) score of 8-14 (8-14 versus 3-7, p = 0.016; 15 versus 3-7, p = 0.55); and aneurysm coiling (p = 0.017). Patients with an initial GCS score of 8-14 after aneurysm-associated SAH had a 2.5-fold higher risk of receiving a VP shunt than those with a GCS score of 3-7. Those with a GCS of 15 had a 50% lower risk of becoming shunt dependent than did the subgroup with a GCS score of 8-14. To clarify and strengthen these observations, prospective, randomized trials are needed.

Rapid and accurate anatomical localization of implanted subdural electrodes in a virtual reality environment.

BACKGROUND: An accurate and rapid anatomical localization of implanted subdural electrodes is essential in the invasive diagnostic process for epilepsy surgery. OBJECTIVE: To demonstrate our experience with a three-dimensional (3D) virtual reality simulation software (Dextroscope®, Bracco Imaging, Milano, Italy) in the postoperative localization of subdural electrodes. METHODS: Postoperative thin-slice computed tomography (CT) scans were coregistered to preoperative 3D magnetic resonance (MR) images in the Dextroscope environment in 10 patients. Single-electrode contacts were segmented and their positions in relation to specific brain anatomic structures were obtained by 3D reconstruction within the Dextroscope environment. The spatial accuracy was tested by comparing the positions of the electrode contacts as visible in the 3D reconstruction with intraoperative photographs. Image processing time was also recorded. RESULTS: The 3D stereoscopic reconstruction provided an accurate representation of the implanted electrodes with highly detailed visualization of the underlying anatomy. The mean absolute difference between 3D reconstruction and intraoperative photographs was 2.4 mm ± 2.2 mm. The processing time to obtain the 3D reconstructions did not exceed 15 minutes. CONCLUSIONS: The results indicate that the 3D virtual reality simulation software used in our series is a useful tool for rapid and precise localization of subdural electrodes implanted for invasive electroencephalography (EEG) recordings.

Intraoperative low-field MR-guided frameless stereotactic biopsy for intracerebral lesions.

BACKGROUND: To present our intraoperative low-field magnetic resonance imaging (ioMRI) technique for stereotactic brain biopsy in various intracerebral lesions. METHOD: Seventy-eight consecutive patients underwent stereotactic biopsies with the PoleStar N-20/N-30 ioMRI system and data were evaluated retrospectively. Biopsy technique included ioMRI before surgery, followed by insertion of the biopsy cannula in the lesion, and ioMRI before and after biopsy. Statistical analysis was performed to compare subgroups using Excel and SPSS statistic software. RESULTS: In all patients, stereotactic biopsy was possible, with a mean intraoperative surgery time of 86.2 ± 28.6 min and a mean hospital stay of 11.6 ± 4.6 days. In 97.4 % (n = 76), histology was conclusive, representing 58 brain tumors and 18 other pathologies. Five patients were biopsied previously without conclusive diagnosis, and all biopsies were conclusive this time. Mean cross-sectional lesion size in MRI T1 with contrast (n = 64) was 6.9 ± 5.7 cm(2), and in lesions without T1 contrast enhancement (n = 14), T2 mean cross-sectional lesion size was 5.5 ± 3.9 cm(2). Mean distance from the cortex surface to the lesion was 3.4 ± 1.2 cm. One patient suffered from a postoperative wound dehiscence; neither clinically or radiologically significant hemorrhage after surgery, nor intraoperative complications occurred. CONCLUSIONS: Low-field ioMR-guided frameless stereotactic biopsy accurately diagnosed different intracerebral lesions without major complications for the patients, and within an acceptable surgery time and hospital stay. In repeated non-conclusive biopsies in particular, low-field ioMRI offers a technique for arriving at a diagnosis.

Soluble α-klotho: a novel serum biomarker for the activity of GH-producing pituitary adenomas.

OBJECTIVE: Klotho is a lifespan-influencing gene expressed mainly in the kidneys. Soluble α-Klotho (αKL) is released into the circulation. In this study, we present baseline αKL serum levels of patients with acromegaly compared with controls with other pituitary adenomas and assess changes following transsphenoidal surgery. DESIGN: Prospective controlled study. METHODS: We measured soluble αKL (sandwich ELISA) and IGF1 (RIA) in sera of 14 patients (eight females and six males) with active acromegaly and in 22 control patients (13 females and nine males) operated for non-GH-producing pituitary adenomas. Immunohistochemical staining for Klotho was performed in resected adenomas and in normal pituitary tissue samples. RESULTS: Soluble αKL was high in the acromegaly group preoperatively (median 4217 pg/ml, interquartile range (IQR) 1812-6623 pg/ml) and declined after surgery during early follow-up (2-6 days; median 645 pg/ml, IQR 550-1303 pg/ml) (P<0.001) and during late follow-up (2-3 months post-operatively; median 902 pg/ml, IQR 497-1340 pg/ml; P<0.001). In controls, preoperative soluble αKL was significantly lower than in acromegalics, 532 pg/ml (400-677 pg/ml; P<0.001). Following surgery, soluble αKL remained low during early and late follow-up - changes over time within the control group were not statistically significant. These results were independent of age, sex and kidney function. Klotho staining was equal or slightly decreased in GH-positive adenomas compared with controls. CONCLUSION: High soluble αKL serum levels were specific to GH-producing adenomas and decreased rapidly following adenoma removal. Thus, soluble αKL appears to be a new specific and sensitive biomarker reflecting disease activity in acromegaly. Similar Klotho staining patterns in controls and acromegalics suggest that the rise in serum αKL is caused by systemic actions of pituitary GH rather than due to increased expression of Klotho by the pituitary (adenoma).

Excessively elevated C-reactive protein after surgery for temporal lobe epilepsy.

OBJECTIVE: We present a series of 87 patients who underwent anteromesial temporal lobe resections for therapy refractory temporal lobe epilepsy. In addition to seizure outcome, we observed excessively elevated CRP-levels in this patient population. METHODS: We followed 87 patients (m=39, f=48; mean age 33.73±12.92, range 5-67 years) who underwent surgery between July 2003 and November 2011. Seizure outcome was classified in all patients according to the ILAE-classification by Wieser et al. (mean follow-up: 38.72 months). CRP levels were measured in 59 patients of the epilepsy surgery group and in a control group of 44 consecutive patients with supratentorial tumors (22 glioblastomas, 22 meningiomas). RESULTS: Clinical benefit was seen in 96.6% of the patients (ILAE classes 1-4), 80.5% were completely seizure free (ILAE class 1). Post-OP CRP values were significantly higher in the epilepsy group (n=59; mean CRP peak value: 100.86 mg/l, range: 16-258 mg/l) compared to the control group (n=44; mean CRP peak value: 36.85 mg/l, range: 0.4-233 mg/l) (p<0.001), but the correlation of mean CRP value and mean temperature peak is weak (r=0.31). CONCLUSIONS: Seizure outcome after surgery for temporal lobe epilepsy was excellent, CRP levels were excessively elevated in these patients in the absence of clinical infection and significantly higher compared to resections of supratentorial lesions.

Impact of ultra-low-field intraoperative magnetic resonance imaging on extent of resection and frequency of tumor recurrence in 104 surgically treated nonfunctioning pituitary adenomas.

OBJECTIVE: To analyze the impact of intraoperative ultra-low-field magnetic resonance imaging (MRI) on the extent of tumor resection in nonfunctioning pituitary adenomas (NFPAs). METHODS: Retrospective analysis was performed of 104 consecutive cases undergoing intraoperative MRI-guided transsphenoidal surgery for NFPA. General patient data; endocrinologic parameters; neurologic examinations; preoperative and postoperative symptoms; preoperative, intraoperative, and postoperative imaging; and proliferation index were evaluated with an overall mean follow-up of 34 months. RESULTS: The use of intraoperative MRI led to an increase of the overall remission rate by 52.2%, from 44.2% to 67.3%. Tumor characteristics such as size and invasiveness had an important impact on postoperative remission rate. In patients with macroadenoma and without previous pituitary surgery, a remission rate of 82.2% was achieved. Overall, the sensitivity of intraoperative MRI in the study was 32.4%. There were no false-positive interpretations. A higher proliferation index was found in the 15 patients with postoperative enlargement of residual adenomas or tumor recurrence compared with the other patients of the study group. CONCLUSIONS: This study shows that the outcome of surgical treatment of NFPAs was improved by the use of intraoperative MRI owing to more radical resection. The remission rate seems to depend on tumor characteristics. Recurrent disease might be reduced by the use of intraoperative MRI leading to more complete surgical resection of NFPAs.

Cerebrospinal fluid leaks after planned intradural spine surgery: a single-center analysis of 91 cases.

UNLABELLED: BACKGROUND AND STUDY OBJECT: A leak-proof dura closure after elective surgery for intradural spinal lesions is important to achieve an uncomplicated postoperative course. Because many different closure techniques and dura substitutes exist, we tried to identify the superior material and technique to avoid cerebrospinal fluid leaks (CSFLs). PATIENTS AND METHODS: Between 2004 and 2009, 91 patients underwent surgical treatment of intradural spinal pathologies with primary dura closure with or without the use of dura substitutes at our institution. Pre- and postoperative images and the clinical course were analyzed retrospectively with respect to the occurrence of CSFL. RESULTS: In 34% of the 91 patients, radiological signs of CSFL were observed. A total of 12 patients (13%) were symptomatic for CSFL and required a single puncture, lumbar drain, or surgical revision. No significant relation between CSFL and patient characteristics, underlying diagnosis, localization, or extension was noted. In contrast, the incidence of CSFL was significantly increased if more than one substitute for dura closure was used. The results showed that 41.7% of these patients showed radiological signs of CSFL as compared with 10.4% of patients in which only a single material was used. CONCLUSION: In our study, none of the applied products appeared to be superior to the others. Surgery with the combined use of multiple dura closure substitutes was associated with the enhanced incidence of postoperative CSFL. However, our findings concerning the various dura sealants could not be used to compare those different materials, due to the great variety of combinations of dura sealants and the retrospective analysis of the data.

Case report: Trabecular juvenile ossifying fibroma presenting as a sellar mass.

A 15-year-old girl presented with left occulomotor nerve palsy and was found to have a space occupying lesion of the sellar region with invasion of the left cavernous sinus. A transsphenoidal approach lead to subtotal removal of a solid tumor with some remnants in the cavernous sinus and revealed the diagnosis of trabecular juvenile ossifying fibroma (JOF). A repeat magnetic resonance imaging was obtained within 1 month that showed intrasellar recurrence and growing tumor in the cavernous sinus. Therefore, a combined transsphenoidal and transcranial approach was performed to more aggressively remove the tumor. Subsequently, adjuvant proton radiotherapy was performed. JOF of the trabecular type is a rare fibro-osseous lesion of the craniofacial skeleton almost exclusively occurring in the maxilla or the mandible. To our knowledge, this is the first case of this tumor entity presenting as a sellar mass.

An unusual cure for acromegaly.

The authors present the case of a 30-year-old female patient with acromegaly whose disease had not been cured after transcranial neurosurgery, two transsphenoidal surgeries and stereotactic radiosurgery. She required treatment with octreotide and pegvisomant to normalise growth hormone levels. Seven years after the diagnosis of acromegaly, she noticed acute vision loss in her left eye and presented with meningism. She had an intrasellar abscess which was confirmed and treated by surgical drainage. As a result of the abscess, she was cured of acromegaly and able to discontinue both octreotide and pegvisomant.

Aesthetic outcome in patients after polymethyl-methacrylate (PMMA) cranioplasty - a questionnaire-based single-centre study.

OBJECTIVES: Acquired skull deformities are common and most likely treated surgically by cranioplasty. Since data on patient aesthetic outcome after cranioplasty are rare in literature, we aimed to assess patient satisfaction after polymethyl-methacrylate (PMMA) cranioplasty in this study using a questionnaire. METHODS: A patient questionnaire was developed to evaluate the grade of satisfaction after surgery. After approval by the institutional ethical review board, we were allowed to send to all 115 patients, who received a cranioplasty from 2001 to 2008 at the University Hospital of Zurich, our questionnaire once to retrospectively analyze the patient response together with the patient hospital records. RESULTS: Out of 115 patients, 36 patients were lost to follow-up and our questionnaire was sent out once to 79 patients. Sixty-three of 79 patients replied to the questionnaire (79·7%) and 16 did not reply. Seventeen declined to participate in this study and out of the remaining 46 patients (58·2%, 18 women, mean age 54 years, range 20-83 years), who agreed to participate in this study, 22 (47·8%) judged their cranioplasty to be aesthetically 'excellent', 16 (34·8%) 'favorable' and 4 (8·7%) 'poor'. Another four patients (8·7%) were not satisfied, asking for a surgical revision. Patient age and gender was not related to the assessment of the aesthetic result. A higher satisfaction grade was found in patients with primary PMMA cranioplasty compared to PMMA cranioplasty implanted during a second surgery (Fisher's exact test, P = 0·031). A dent was strongly associated with absence of satisfaction (P<0·01, Fisher's exact test). CONCLUSION: Our questionnaire was suitable to assess patient satisfaction after cranioplasty. Localization of cranioplasty showed to be an important factor of aesthetic outcome, especially in the fronto-temporal region where a carefully planned reconstruction should be performed to guarantee an excellent grade of satisfaction after surgery.

Rare suprasellar glioblastoma: report of two cases and review of the literature.

BACKGROUND AND IMPORTANCE: The suprasellar and hypothalamic/chiasmatic regions can harbor a broad range of pathologic conditions, both neoplastic and nonneoplastic; however, malignant gliomas are extremely rare in those regions. CLINICAL PRESENTATIONS: Patient 1 was a 70 year-old man with weight loss and rapidly progressive visual impairment. A mass centered in the hypothalamus was detected on magnetic resonance (MR) imaging. The second patient, a 45 year-old woman, complained of visual symptoms and headaches. MR imaging revealed a combined intra- and suprasellar mass. In both instances, the preoperative differential diagnosis favored craniopharyngioma. Histological examination confirmed the diagnosis of glioblastoma. CONCLUSION: We report two rare adult cases of hypothalamic/chiasmatic glioblastoma. The authors review the literature, highlighting the importance of considering this rare entity in the differential diagnosis of suprasellar and hypothalamic lesions.

Resection of pediatric intracerebral tumors with the aid of intraoperative real-time 3-D ultrasound.

PURPOSE: Intraoperative ultrasound (IOUS) has become a useful tool employed daily in neurosurgical procedures. In pediatric patients, IOUS offers a radiation-free and safe imaging method. This study aimed to evaluate the use of a new real-time 3-D IOUS technique (RT-3-D IOUS) in our pediatric patient cohort. MATERIAL AND METHODS: Over 24 months, RT-3-D IOUS was performed in 22 pediatric patients (8 girls and 14 boys) with various brain tumors. These lesions were localized by a standard navigation system followed by analyses before, intermittently during, and after neurosurgical resection using the iU22 ultrasound system (Philips, Bothell, USA) connected to the RT-3-D probe (X7-2). RESULTS: In all 22 patients, real-time 3-D ultrasound images of the lesions could be obtained during neurosurgical resection. Based on this imaging method, rapid orientation in the surgical field and the approach for the resection could be planned for all patients. In 18 patients (82%), RT-3-D IOUS revealed a gross total resection with a favorable neurological outcome. CONCLUSION: RT-3-D IOUS provides the surgeon with advanced orientation at the tumor site via immediate live two-plane imaging. However, navigation systems have yet to be combined with RT-3-D IOUS. This combination would further improve intraoperative localization.

Advantages and limitations of intraoperative 3D ultrasound in neurosurgery. Technical note.

Three-dimensional ultrasound (US) technology is supposed to help combat some of the orientation difficulties inherent to two-dimensional US. Contemporary navigation solutions combine reconstructed 3D US images with common navigation images and support orientation. New real-time 3D US (without neuronavigation) is more time effective, but whether it further assists in orientation remains to be determined. An integrated US system (IGSonic, VectorVision, BrainLAB, Munich Germany) and a non-integrated system with real-time 3D US (iU22, Philips, Bothell, USA) were recently compared in neurosurgical procedures in our group. The reconstructed navigation view was time-consuming, but images were displayed in familiar planes (e.g., axial, sagittal, coronal). Further potential applications of US angiography and pure US navigation are possible. Real-time 3D images were displayed without the need for an additional acquisition and reconstruction process, but spatial orientation remained challenging in this preliminary testing phase. Reconstructed 3D US navigation appears to be superior with respect to spatial orientation, and the technique can be combined with other imaging data. However, the potential of real-time 3D US imaging is promising.

Intraoperative magnetic resonance imaging-guided transsphenoidal surgery for giant pituitary adenomas.

Giant pituitary adenomas (GPAs), defined as >/=40 mm in one extension, present a challenging subgroup of pituitary adenomas in terms of radical tumor removal and complication rates. The potential impact of intraoperative magnetic resonance imaging (iMRI) is investigated in a consecutive series and the results compared to the literature. From November 2004 until February 2005, six (five male) patients were operated for GPAs via an iMRI-guided transsphenoidal approach in the PoleStar N20. Clinical, endocrinological, and neuroradiological outcomes (at 3 months and yearly postoperative over 4 years) were assessed. Mean age was 46 years (range, 34-60). All patients presented with preoperative visual field defects, five with pituitary failure. Five adenomas were clinically nonfunctioning, one was producing GH and TSH. Preoperative imaging showed invasion of the cavernous sinus in all and extension to the interventricular foramen in two patients (one with occlusive hydrocephalus). Resection was total in four and subtotal (small cavernous sinus remnants) in two patients, leading to transsphenoidal reoperation in one patient. Visual acuity and fields improved in all six patients. The patient with occlusive hydrocephalus developed a postoperative cerebrospinal fluid leak (subsequently revised), two patients developed temporary, one permanent central diabetes insipidus, and one of them transient hyponatremia. Compared to the preoperative situation, endocrine status in the long-term follow-up (mean, 25 months) remained unchanged in four and worsened in two. Two patients were considered not to require hormone replacement therapy. IMRI supports transsphenoidal resections of GPAs because residual adenoma and related risk structures are easily detected and localized intraoperatively, extending the restricted visual access of the microscope beyond mere surface anatomy to a three-dimensional view. More radical removal of adenomas in a single surgical session combined with low complication rates are accomplished. This may add to a favorable clinical and endocrinological outcome in GPAs.