[Characteristics and Treatment of Young Adult-Onset Hydrocephalus].

Certain congenital or developmental anomalies of adult-onset hydrocephalus often share clinical symptoms with idiopathic normal pressure hydrocephalus(iNPH). These anomalies include long-standing overt ventriculomegaly in adults(LOVA), persistent Break's pouch cyst(PBC)and panventriculomegaly(PaVM). Certain patients with adult-onset hydrocephalus might have congenital or secondary etiologies, such as late-onset idiopathic aqueductal stenosis(LIAS), and syndrome of hydrocephalus in young and middle-aged adults(SHYMA). Some of these conditions have unknown etiologies, and the definitions of LOVA differ between Japan and overseas. Adult-onset hydrocephalus usually presents with chronic onset, with younger patients tending to have headaches and older patients tending to have iNPH symptoms. In cases where the third ventricle floor bulging, endoscopic third ventriculostomy(ETV)is often performed. However, the arachnoid membrane of the pontine cistern might be strong, and the brain stem might be shifted to the clivus due to the enlarged fourth ventricle. For treating such patients, experienced hands might be needed. At present, it is necessary to carefully examine the cerebrospinal fluid dynamics in each patient and select the best test and treatment.

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition): Endorsed by the Japanese Society of Normal Pressure Hydrocephalus.

Among the various disorders that manifest with gait disturbance, cognitive impairment, and urinary incontinence in the elderly population, idiopathic normal pressure hydrocephalus (iNPH) is becoming of great importance. The first edition of these guidelines for management of iNPH was published in 2004, and the second edition in 2012, to provide a series of timely, evidence-based recommendations related to iNPH. Since the last edition, clinical awareness of iNPH has risen dramatically, and clinical and basic research efforts on iNPH have increased significantly. This third edition of the guidelines was made to share these ideas with the international community and to promote international research on iNPH. The revision of the guidelines was undertaken by a multidisciplinary expert working group of the Japanese Society of Normal Pressure Hydrocephalus in conjunction with the Japanese Ministry of Health, Labour and Welfare research project. This revision proposes a new classification for NPH. The category of iNPH is clearly distinguished from NPH with congenital/developmental and acquired etiologies. Additionally, the essential role of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in the imaging diagnosis and decision for further management of iNPH is discussed in this edition. We created an algorithm for diagnosis and decision for shunt management. Diagnosis by biomarkers that distinguish prognosis has been also initiated. Therefore, diagnosis and treatment of iNPH have entered a new phase. We hope that this third edition of the guidelines will help patients, their families, and healthcare professionals involved in treating iNPH.

A multi-center, prospective study on the progression rate of asymptomatic ventriculomegaly with features of idiopathic normal pressure hydrocephalus on magnetic resonance imaging to idiopathic normal pressure hydrocephalus.

INTRODUCTION: Our previous community-based study demonstrated that some individuals with AVIM [asymptomatic ventriculomegaly with features of idiopathic normal pressure hydrocephalus (iNPH) on magnetic resonance imaging (MRI)] progressed to iNPH in several years. In this hospital-based study, we investigated the progression rate from AVIM to iNPH and its possible predictors. METHODS: We conducted a prospective study of participants with AVIM from several medical institutions/hospitals in Japan. AVIM is defined as "asymptomatic ventriculomegaly with features of iNPH on MRI"; in the present study, asymptomatic was defined as "0 (no symptoms) or 1 (presence of only subjective, but not objective, symptoms) on the iNPH Grading Scale (iNPH-GS)." We also measured possible predicting factors for AVIM-to-iNPH progression, including age, sex, body weight, blood pressure, diabetes mellitus, dyslipidemia, history of mental disease/head injury/sinusitis/smoking/alcohol-intake, Evans index, and the presence of DESH (disproportionately enlarged subarachnoid-space hydrocephalus) findings on brain MRI, and analyzed these potential predictive values. RESULTS: In 2012, 93 participants with AVIM were registered and enrolled in the study. Of these, 52 participants were able to be tracked for three years (until 2015). Of the 52 participants, 27 (52%) developed iNPH during the follow-up period (11 definite, 6 probable, and 10 possible iNPH), whereas 25 participants remained asymptomatic in 2015. Among the possible predictive factors examined, the baseline scores of iNPH-GS predicted the AVIM-to-iNPH progression. CONCLUSIONS: The multicenter prospective study demonstrated that the progression rate from AVIM to iNPH was ~17% per year, and the baseline scores of iNPH-GS predicted the AVIM-to-iNPH progression.

Postnatal development of Blake's pouch cyst: a case report and new insight for its pathogenesis.

Blake's pouch cyst (BPC), a rare cystic malformation in the posterior fossa, is believed to be caused by the congenital expansion of the posterior membranous area that normally regresses during embryogenesis. However, due to the wide spectrum of the onset pattern and age of patients, the natural history and the pathogenesis are poorly understood. The authors describe the case of a girl who admitted with headache and right abducens nerve paresis at the age of 3 years and 10 months. Magnetic resonance (MR) imaging demonstrated a tetraventricular hydrocephalus, an open aqueduct, and a posterior fossa cyst compatible with BPC. Multiple tumors were also noticed in the ventricular wall. Tumor biopsy and an endoscopic third ventriculostomy were performed. Intraoperative observation confirmed the BPC, and pathological diagnosis was pilomyxoid astrocytoma. In retrospect, MR imaging was performed twice in the past, at the age of 8 months and again at 22 months, and no anomaly was detected, suggesting that Blake's pouch was once regressed. Therefore, a BPC in this patient was certainly developed after her second or third year of life. The ventricular tumors may influence the cerebrospinal fluid (CSF) absorption, which triggered the re-expansion of BPC from the possible remnant of Blake's pouch. This is a rare but important report providing evidence that in addition to the classic congenital BPC in which the remnant of Blake's pouch remains persistent, there could be postnatal or secondary BPC, which develops after birth. Possible mechanisms include that the remnant of Blake's pouch, which originally disappears, may re-expand postnatally in association with unknown trigger or a change in CSF dynamics or absorption.

Assessment of a quick reference table algorithm for determining initial postoperative pressure settings of programmable pressure valves in patients with idiopathic normal pressure hydrocephalus: SINPHONI subanalysis.

BACKGROUND: Management of overdrainage complications in shunted patients with idiopathic normal pressure hydrocephalus (INPH) remains a difficult task despite the use of programmable pressure valves. OBJECTIVE: To assess the usefulness of a quick reference table (QRT) algorithm for achieving a suitable initial programmable pressure valve setting in INPH patients who participated in the Study for INPH on Neurological Improvement (SINPHONI). METHODS: One hundred registered patients diagnosed with probable INPH were treated with ventriculoperitoneal shunts using Codman-Hakim programmable valves (CHPVs). In this series, the initial CHPV setting was decided prospectively according to the QRT algorithm. Shunt effectiveness, complications, and the number of CHPV readjustments during follow-up periods were investigated. RESULTS: Eighty patients were considered better than shunt responders (more than 1 point improvement in modified Rankin scale at any follow-up period). Readjustments of CHPVs within 3 months after treatment with ventriculoperitoneal shunt were performed 56 times in 44 cases (44%, 0.56 times/patient). Low-pressure headache occurred in 9 patients, all of whom improved by readjustment alone. Nontraumatic subdural fluid collections and chronic subdural hematomas occurred in 15 cases (15%); however, most of the cases were subclinical and improved after CHPV readjustments alone. Burr hole irrigation was necessary in only 1 case. CONCLUSION: Use of the QRT algorithm was associated with a decrease in postoperative CHPV readjustments and serious overdrainage complications during the follow-up period. The QRT algorithm is an easy, safe, and effective method for determining the initial CHPV pressure setting in INPH patients.

Nationwide investigation of the current status of therapeutic neuroendoscopy for ventricular and paraventricular tumors in Japan.

OBJECT: The authors report their investigation on the current status of neuroendoscopic biopsy for ventricular and paraventricular tumors as well as treatment for associated hydrocephalus in Japan. METHODS: Patients who had undergone therapeutic neuroendoscopy between 2005 and 2009 were included in this study. The main items examined were age; sex; localization of tumor; pathological diagnosis using biopsy; the presence, treatment, and efficacy of treatment of associated hydrocephalus; perioperative complications; activities of daily living (ADL) before and after therapeutic neuroendoscopy; and the presence of dissemination during the postoperative course. RESULTS: Seven hundred fourteen patients from 123 sites (462 male and 252 female patients, mean age 33.3 years) were enrolled. Localization of the tumor was mainly classified into the lateral ventricle in 91 patients, the third ventricle in 339, the fourth ventricle in 18, the suprasellar region in 75, and other paraventricular areas in 191 patients. The most commonly observed tumors were germ cell tumors in the third ventricle (177 cases [39%]), cystic lesions in the suprasellar region (56 cases [75%]), and astrocytic tumors in the thalamus-basal ganglia (71 cases [38%]). Although 641 (92.8%) of 691 patients could receive neuroendoscopic diagnosis using biopsy, the diagnosis obtained with endoscopic biopsy differed from the final diagnosis based on subsequent craniotomy in 18 patients and clinical course in 3 patients. Of these 21 patients, 7 had astrocytic tumors, 4 had pineal tumors, 6 had germ cell tumors, and 4 had other tumors. The final diagnostic accuracy rate was 89.7%. Associated hydrocephalus was observed in 517 patients (72.4%), of whom 316 and 39 underwent third ventriculostomy and fenestration of the septum, respectively. The response rates were 96.2% and 89.7%, respectively. Third ventriculostomy was required for recurrence of hydrocephalus in 41 patients (13.0%), and the long-term response rate was therefore 83.2% (263 of 316 patients). Perioperative complications other than fever, such as new onset of or progressive hydrocephalus, infection due to CSF leakage, and bleeding in the ventricle or tumor, were found in 81 patients (11.3%). The median Karnofsky Performance Scale score before endoscopic surgery was 80, but it increased to 90 after surgery. The score was thus significantly increased after surgery (p < 0.0001, Mann-Whitney U-test). Activities of daily living after surgery decreased due to perioperative complications in 15 patients (2.1%). The incidence of new dissemination after endoscopic biopsy was 6.8% and not high compared with routine surgical treatment. CONCLUSIONS: The authors concluded that neuroendoscopic diagnosis using biopsy for ventricular and paraventricular tumors is adequately accurate and safe. It was demonstrated that endoscopic procedures play important roles not only in the treatment of hydrocephalus associated with intra- and paraventricular tumors but also in significantly improving ADL. Furthermore, the long-term outcome of endoscopic third ventriculostomy was clearly favorable.

Endoscopic endonasal pituitary and skull base surgery.

Here we describe the procedures of endoscopic pituitary and skull base surgery in our institute. We also review the literature to reveal recent advances in this field. Endonasal approach via the sphenoid ostium was carried out for pituitary lesions without the nasal speculum. Postoperative nasal packing was basically not needed in such cases. For meningiomas, craniopharyngiomas, and giant pituitary adenomas, which required intra-dural procedures, nasal procedures such as middle nasal conchotomy and posterior ethmoidectomy, and skull base techniques such as optic canal decompression and removal of the planum sphenoidale were carried out to gain a wider operative field. Navigation and ultrasonic Doppler ultrasonography were essential. Angled endoscopes allowed more successful removal of tumors under direct visualization extending into the cavernous sinus and lower clivus. If cerebrospinal fluid (CSF) leakage occurred during operation, the dural opening was covered with a vascularized mucoseptal flap obtained from the nasal septum. Lumbar drainage system to prevent postoperative CSF rhinorrhea was frequently not required. Angled suction tips, single-shaft coagulation tools, and slim and longer holding forceps, all of which were newly designed for endoscopic surgery, were essential for smoother procedures. Endonasal endoscopic pituitary surgery allows less invasive transsphenoidal surgery since no postoperative nasal packing and less dependence on lumbar drainage are needed. Endoscopic pituitary surgery will be more common and become a standard procedure. Endoscopic skull base surgery has enabled more aggressive removal of extrasellar tumors with the aid of nasal and skull base techniques. Postoperative CSF leakage is now under control due to novel methods which have been proposed to close the dural defect in a water-tight manner. Endoscopic skull base surgery is more highly specialized, so needs special techniques and surgical training. Patient selection is also important, which needs collaboration with ear, nose, and throat specialists. As a safe and successful procedure in skull base surgery, this complex procedure should be carried out only in specialized hospitals, which deal with many patients with skull base lesions.

Endoscopic endonasal trans-sphenoidal optic nerve decompression for traumatic optic neuropathy--technical note.

The endoscopic endonasal trans-sphenoidal approach can decompress the traumatized and swollen optic nerve without brain retraction. Three cases of traumatic optic neuropathy (TON) were treated by this endoscopic approach. We performed 58 endoscopic endonasal trans-sphenoidal approaches in 52 patients between April 2006 and December 2007. Three patients, 2 men and a woman aged 42-66 years, with TON were treated by endoscopic endonasal trans-sphenoidal optic nerve decompression. Adequate decompression of the optic canal was observed in all three patients. Two experienced improved visual function, but the third did not. No surgical complications were observed in any patient. We were able to reach the optic canal above the opticocarotid recess near the orbit. Endoscopic endonasal trans-sphenoidal optic canal decompression using a navigation system may be a safe and effective surgical strategy in carefully selected patients with TON.

Endoscopic endonasal skull base reconstruction using a nasal septal flap: surgical results and comparison with previous reconstructions.

The objective of this study is to evaluate the usefulness and reliability of endoscopic endonasal skull base reconstructions using a nasal septal flap. This study is designed as a retrospective review. Between April 2005 and November 2009, we performed 32 endoscopic endonasal skull base reconstructions for closure of large dural defects. Eleven patients underwent reconstructions using fat grafts or the fascia lata (non-flap group). Twenty one patients underwent reconstructions using a nasal septal flap with a balloon catheter (flap group). Incidence of postoperative cerebrospinal fluid (CSF) leaks and perioperative insertion rate of external lumbar drain (ELD) were compared between the two groups. Postoperative CSF leaks occurred in two patients (9.5%) in the flap group. Three patients (27.3%) presented CSF leaks in the non-flap group. The rate of insertion of ELD was 81.8% in the non-flap group. In the flap group, one patient (4.8%) should be placed with ELD postoperatively. The incidence of postoperative CSF leaks in the flap group was lower than in the non-flap group, whereas the rate of insertion of ELD in the non-flap group was higher than in the flap group. Endoscopic endonasal skull base reconstruction using a nasal septal flap without ELD seems to be useful and reliable for ventral skull base defects after endoscopic endonasal approaches as compared with our previous single-layer reconstructions using free fat grafts or fascia lata. The long-term effectiveness of nasal septal flaps to prevent intracranial complications should be confirmed.

[Endoscopic endonasal surgery for extrasellar tumors: case presentation and its future perspective].

BACKGROUND AND OBJECTIVES: Endoscopic endonasal transsphenoidal surgery has been performed because of its advantages such as less invasive surgical management and more aggressive tumor removal of extrasellar lesions. In 2003, we began endoscope-assisting surgery. In 2006, we completely switched to the endoscopic endonasal approach without microscope or nasal specula. Today, we report endoscopic pituitary and skull base surgery in our institute. The endonasal approach via the sphenoid ostium was carried out without nasal specula. Postoperative nasal packing was basically not needed in such cases. In cases with meningiomas, craniopharyngiomas and giant pituitary adenomas, which needed intra-dural procedure, nasal procedures such as middle nasal conchotomy, posterior ethmoidectomy and skull base techniques such as optic canal decompression and removal of the planum sphenoidale were carried out to gain the wider operative field toward anterior skull base and lower clivus. Navigation and US-Doppler were essential. Angled endoscope attained more successful removal of tumor under direct visualization extending into the cavernous sinus (GH secreting ademomas) and lower clivus (chordoma). In the case of CSF (cerebrospinal fluid) leakage during operation, a newly designed balloon catheter was placed in the sphenoid sinus to fix the abdominal fat and fibrin glue at the leakage point. In recent cases, dural opening has been sutured. In the combination of such techniques, a lumbar drainage system to prevent postoperative CSF rhinorrhea became needless in many cases. Angled suction tips, single-shaft coagulation tools and slim and longer holding forceps, all of which were newly designed for endoscopic surgery, were essential for smoother procedure. Endonasal endoscopic pituitary surgery has resulted in less invasive transsphenoidal surgery since no postoperative nasal packing is needed and there is less dependency on lumbar drainage. Although better techniques to prevent postoperative CSF leakage needs to be developed, this endoscopic pituitary surgery will become more common and will become a standard procedure. Endoscopic skull base surgery has enabled more aggressive removal of extrasellar tumors with the aid of nasal and skull base techniques. This endoscopic skull base surgery is more highly specialized, needs special techniques and surgical training. Selection of patients is also important. This also needs collaboration with ENT (ear, nose, throat) doctors. To be acknowledged as a safe and successful procedure in skull base surgery, this complex procedure may be preferably carried out only in center hospitals, which deal with many patients with a skull base lesion.

Akt/protein kinase B overexpression as an accurate prognostic marker in adult diffuse astrocytoma.

BACKGROUND: Akt/Protein kinase B (PKB) is a common downstream molecule of Ras signaling essential for cell survival. In an attempt to find a novel prognostic marker of diffuse astrocytoma, we performed an immunohistochemical analysis of Akt/PKB with regard to patient survival and regrowth patterns. METHODS: Twenty-four adult patients with diffuse astrocytoma were similarly managed without early post-operative radiotherapy and followed up for a median period of 7.5 years. They were analysed by immunohistochemistry for Akt/PKB expression as well as p53 protein accumulation, epidermal growth factor receptor (EGFR) expression, and MIB-1 labeling index. The prognostic significance of each molecular covariate was tested by multivariate analysis using Cox's proportional hazard model including age, performance status, and extent of surgical resection. FINDINGS: Akt/PKB overexpression significantly correlated with both shorter overall survival (OS) and progression-free survival (PFS) (p = 0.0110). All the Akt/PKB-positive patients with post-operative residual tumours experienced tumour recurrences, whereas only a small fraction of the Akt/PKB-negative individuals had recurrences (p = 0.0070). Invasive recurrence into surrounding brain occurred only in the Akt/PKB-overexpressed tumours. In contrast, MIB-1 labeling index correlated only with OS, while p53 protein accumulation correlated only with PFS. The Cox's proportional hazard model identified Akt/PKB overexpression as a significant prognostic factor for shorter PFS (p = 0.0117). CONCLUSION: These results show that Akt/PKB overexpression would be suggestive of malignant progression and invasive regrowth of diffuse astrocytoma, and it can serve as a novel prognostic marker for this tumour.

MR imaging of normal perivascular space expansion at midbrain.

BACKGROUND AND PURPOSE: A previous investigation of the MR imaging findings in the midbrain reported expanded perivascular (PV) spaces in only the ponto-mesencepalic junction (PMJ) in 20% of healthy subjects, whereas pathologically expanding PV spaces have been reported at the mesencephalo-diencephalic junction (MDJ) as multi-lobulated, cystic lesions with signal intensity compatible with that of CSF that cause aqueductal stenosis. To clarify the anatomical distinctions between normally expanded and pathologically expanding PV spaces, we defined their distribution in the normal midbrain by using high-spatial-resolution MR imaging. METHODS: Heavily T2-weighted MR imaging was performed in 115 adult subjects with neurologic complaints without cerebral disease. Histologic studies were performed from two normal midbrain blocks. RESULTS: Expanded PV spaces were visible at the PMJ in 87% of subjects and at the MDJ in 63% of subjects. On axial images, ovoid or linear lesions with signal intensity compatible to CSF were present behind the cerebral peduncle at both the PMJ and MDJ. These areas varied from less than 1 mm to 5 mm (maximum diameter on coronal sections). Histologic studies confirmed the distribution of expanded PV spaces, as noted on MR images. CONCLUSION: This study, by using high-spatial-resolution MR imaging, revealed that expanded PV spaces were visible at the PMJ and MDJ. Our finding of expanded PV spaces normally present at the MDJ may be related to pathologically expanding PV spaces, which should be kept in mind as a differential diagnosis for intraparenchymal cystic lesions in the midbrain with signal intensity compatible to CSF.

Histologic characteristics of normal perivascular spaces along the optic tract: new pathogenetic mechanism for edema in tumors in the pituitary region.

BACKGROUND AND PURPOSE: Perivascular (PV) spaces are known to distend and cause edema along the optic tract (OT) in pituitary-region tumors. Interstitial fluid may be retained in PV spaces when tumors block their drainage outlets to subarachnoid spaces. However, these spaces and their outlets have not been anatomically elucidated. Our purpose was to evaluate how often large PV spaces are present along the OT and demonstrate their superficial communication points to adjacent subarachnoid spaces. METHODS: We examined serial histologic sections of 10 hemispheric blocks obtained from cadavers without cerebral abnormality. RESULTS: Large PV spaces, 0.5-1.5 mm in maximum height, were always present along the middle portion of the OT. Perforation points of the largest spaces were noted at the medial sulcus of the OT in seven hemispheres and through the OT in three. CONCLUSION: Large PV spaces are present along the middle portion of the OT. Their communication point to adjacent subarachnoid spaces was histologically demonstrated. The locations and variations of the outlet of large PV spaces explain the clinical features of edemas; these findings anatomically support the hypothesis that blockage of the outlets to subarachnoid spaces may play a role in distending the PV spaces and in causing edema in pituitary-region tumors. Only MR imaging has revealed this change; further pathologic investigations are awaited.

Involvement of highly polysialylated neural cell adhesion molecule (PSA-NCAM)-positive granule cells in the amygdaloid-kindling-induced sprouting of a hippocampal mossy fiber trajectory.

The mossy fiber system in the hippocampus of amygdaloid-kindled rats was examined by using highly polysialylated neural cell adhesion molecule (PSA-NCAM) as a marker for immunohistochemical detection of immature dentate granule cells and mossy fibers in combination with bromodeoxyuridine (BrdU) labeling of newly generated granule cells. Statistically significant increases in BrdU-labeled cells and PSA-NCAM-positive cells occurred in the dentate gyrus following kindling. The increase in PSA-NCAM-immunoreactive neurites was confined to the entire stratum lucidum of CA3. Immunoelectron-microscopic examination also revealed that PSA-NCAM-positive immature synaptic terminals of the sprouting mossy fibers increased in the stratum lucidum of CA3 in the kindled rats. The increase in the numbers of PSA-NCAM-positive granule cells correlated well with the increase in the immunopositive neurites and synaptic terminals on the mossy fiber trajectory. The increase in these PSA-NCAM-immunopositive structures is thought to reflect the enhancement of sprouting and synaptogenesis of mossy fibers by a subset of granule cells newly generated during amygdaloid-kindling and suggests that the reorganization of the mossy fiber system on the normal trajectory at least in part contributes to the acquisition and maintenance of an epileptogenic state.

MR imaging study of edema-like change along the optic tract in patients with pituitary region tumors.

BACKGROUND AND PURPOSE: Edema-like change along the optic tract commonly occurs in association with craniopharyngiomas. The aim of this study was to clarify whether it occurs in association with other common pituitary region tumors and to elucidate its mechanism as seen on MR images. METHODS: Fifty patients with pituitary region tumors that were touching or compressing the optic pathway underwent heavily T2-weighted MR imaging before and after treatment. RESULTS: Edema-like change along the optic tract was visible on the images of four of 25 pituitary adenomas, eight of 11 craniopharyngiomas, one germ cell tumor, and one malignant lymphoma and was not visible on the images of seven meningiomas and five Rathke's cleft cysts. After therapeutic decompression of the optic pathway, the edema-like change disappeared and large Virchow-Robin spaces, present under normal conditions, became visible along the optic tract. Comparison of pre- and post-treatment coronal and axial view MR images revealed that the edema-like change had been located at, along, and/or around the large Virchow-Robin spaces along the optic tract. CONCLUSION: Edema-like change occurs in association with pituitary region tumors other than craniopharyngiomas. It is related with distension of normally present large Virchow-Robin spaces adjacent to the optic tract. Because Virchow-Robin spaces are speculated to be a drainage route of interstitial fluid into the subarachnoid space, their distension may be related to the fluid retention in and along the Virchow-Robin spaces, the outlet of which into the subpial and/or subarachnoid space(s) is blocked by pituitary region tumors.

Posterior pituitary bright spot in large adenomas: MR assessment of its disappearance or relocation along the stalk.

PURPOSE: To evaluate the disappearance or relocation patterns of posterior pituitary bright spot (PPBS) in the infundibuloneurohypophyseal (INH) system and endocrinologic implications in large pituitary adenomas. MATERIALS AND METHODS: Sixty-nine patients with adenoma and supradiaphragmatic extension were classified into PPBS-visible and PPBS-nonvisible groups on the basis of findings at preoperative T1-weighted magnetic resonance (MR) imaging. The adenoma shapes were classified into hourglass type with indentation and barrel type without indentation at the diaphragmatic level. RESULTS: The PPBS-visible group included 55 (80%) patients. PPBS most commonly occurred at the distal pituitary stalk immediately above the diaphragm in 48 patients with hourglass-type adenoma. In the remaining seven patients with barrel-type adenoma, PPBS occurred in the sella or in varying sites along the pituitary stalk. Postoperatively, two patients, whose PPBS became nonvisible, developed persistent diabetes insipidus. The PPBS-nonvisible group included 14 (20%) patients. Five had hourglass-type and nine had barrel-type adenoma. Occurrence of the barrel type was marked. In these patients, four developed postoperative permanent diabetes insipidus. CONCLUSION: The diaphragm, a probable major anatomic determinant of indentation, may serve as a transportation blockade and facilitate proximal accumulation of PPBS material, as evidenced in the hourglass-type adenoma. PPBS was more commonly nonnvisible in the barrel-type adenoma. The presence of PPBS in the INH system indicates its functional maintenance in large adenomas.

Slit ventricle syndrome after cyst-peritoneal shunting for temporal arachnoid cyst in children--a clinical entity difficult to detect on neuroimaging study.

Slit ventricle syndrome, known to occur from malfunction of the shunt procedure for hydrocephalus, is reported after cyst-peritoneal shunt for temporal arachnoid cyst. Two children aged 12 and 10 years, who underwent cyst-peritoneal shunting for a large temporal arachnoid cyst at the age of 10 and 5 years, respectively, recently experienced several episodes of severe headache. Prior to admission, repeated CT scans did not reveal any morphological change in either of these two patients. Evidence of high intracranial pressure by lumbar tap revealed shunt malfunction. Both patients became free of neurological complaints and deficits after shunt revision. Despite elevated intracranial pressure due to shunt malfunction, neuroimaging studies showed no morphological changes in slit ventricle syndrome. Delay in both the diagnosis and prompt treatment may result in complete loss of visual acuity and even death. It is important to suspect this complication in patients with persistent elevated intracranial pressure symptoms and signs after any shunting procedure, regardless of unchanged neuroimaging studies. Once this is suspected, lumbar tap may be necessary and the choice of treatment is shunt revision.