Pathogenesis of Delayed Tension Intraventricular Pneumocephalus in Shunted Patient: Possible Role of Nocturnal Positive Pressure Ventilation.

BACKGROUND: Delayed intraventricular pneumocephalus is a very rare and potentially serious complication of ventriculoperitoneal shunt. It can occur several months or years after shunting. Its pathogenesis is unclear. We herein discuss the underlying mechanisms and particularly the possible role of positive pressure ventilation. CASE DESCRIPTION: A 60 year-old man presented with a lateral ventricle neurocytoma microsurgically resected complicated by a late-onset (15 months) postoperative hydrocephalus requiring an adjustable ventriculoperitoneal (VP) shunt. One month later, the patient was diagnosed with a sleep apnea and required a continuous positive airway pressure (CPAP) device. A few weeks afterward the patient presented with headaches and alteration of consciousness. CT-Scan revealed a massive intraventricular pneumocephalus associated with a millimetric left petrous bone defect. A transient breakout of the positive ventilation and a subtemporal surgical repair of the defect led to the rapid resolution of the pneumocephalus. DISCUSSION: Delayed intraventricular pneumocephalus requires two conditions: a VP shunt and an osteodural defect. The CPAP may play an important trigger role in the pathogenesis of this complication through a ball valve mechanism. The management relies on transient suspension of the positive ventilation and the surgical repair of the identified defect with or without pressure adjustments of the valve. CONCLUSION: Intraventricular pneumocephalus is a potentially serious complication of patients with a VP shunt and receiving positive pressure ventilation. The introduction of a CPAP device must be discussed with the neurosurgeon beforehand in shunted patients.

The endoscopic intraventricular management of pineal cysts: a minimally invasive modus operandi.

BACKGROUND: The management of pineal cysts is still debatable, especially for asymptomatic incidental ones. For symptomatic cysts associated with hydrocephalus, the surgical management is mandatory and may include either classical microsurgical approaches to the pineal region or endoscopic trans-ventricular approaches in a minimally invasive philosophy. METHOD: The authors expose a stepwise technique to treat a pineal cyst associated with an obstructive hydrocephalus in one procedure gathering a third ventriculostomy followed by an intraventricular marsupialisation of the pineal cyst. CONCLUSION: This endoscopic approach allows the treatment of the hydrocephalus and the pineal cyst in one short minimally invasive procedure.

A rare, high cervical traumatic spinal subdural hematoma.

Spinal subdural hematomas (SSDH) are rare lesions occurring in association with a wide variety of conditions, including anticoagulation, coagulation disorders, spinal anesthesia, lumbar puncture, spinal tumors and vascular malformations. SSDH resulting from trauma are the exception. We present a 62-year-old woman with a rare post-traumatic focal SSDH at C1 with bulbomedullary compression, treated successfully with surgery. A review of the literature revealed 26 patients with traumatic SSDH. The aim of this report is to describe the clinical presentation, imaging characteristics and management of traumatic SSDH. The controversial pathogenesis is also discussed.

Could linear MRI measurements of hippocampus differentiate normal brain aging in elderly persons from Alzheimer disease?

Although mild progressive specific structural brain changes are commonly associated with normal human aging, it is unclear whether automatic or manual measurements of these structures can differentiate normal brain aging in elderly persons from patients suffering from cognitive impairment. The objective of this study was primarily to define, with a standard high resolution MRI, the range of normal linear age-specific values for the hippocampal formation (HF), and secondarily to differentiate hippocampal atrophy in normal aging from that occurring in Alzheimer disease (AD). Two MRI-based linear measurements of the hippocampal formation at the level of the head and of the tail, standardized by the cranial dimensions, were obtained from coronal and sagittal T1-weighted MR images in 25 normal elderly subjects, and 26 patients with AD. In this study, dimensions of the HF have been standardized and they revealed normal distributions for each side and each sex: the width of the hippocampal head at the level of the amygdala was 16.42 +/- 1.9 mm, and its height 7.93 +/- 1.4 mm; the width of the tail at the level of the cerebral aqueduct was 8.54 +/- 1.2 mm, and the height 5.74 +/- 0.4 mm. There were no significant differences in standardized dimensions of the HF between sides, sexes, or in comparison to head dimensions in the two groups. In addition, the median inter-observer agreement index was 93%. In contrast, the dimensions of the hippocampal formation decreased gradually with increasing age, owing to physiological atrophy, but this atrophy is more significant in the group of AD.

Cranial sutures and craniometric points detected on MRI.

The main goal of the study was to determine on MRI the cranial sutures, the craniometric points and craniometric measurements, and to correlate these results with classical anthropometric measurements. For this purpose, we reviewed 150 cerebral MRI examinations considered as normal (Caucasian population aged 20-49 years). For each examination we individualized 11 craniometric landmarks (Glabella, Bregma, Lambda, Opisthocranion, Opisthion, Basion, Inion, Porion, Infra-orbital, Eurion) and three measurements. Measurements were also calculated independently on 498 dry crania (Microscribe 3-DX digitizer). To validate the MRI procedure, we measured four dry crania by MRI and with compass or digital caliper gauges. Cranial sutures always appeared without signal (black), whatever the MRI sequence used, and they are better visualized with a 5 mm slice thickness (compact bone overlapping). Slice dynamic analysis and multiplanar reformatting allowed the detection of all craniometric points, some of these being more difficult to detect than others (Porion, Infra-orbital). The measurements determined by these points were as follows: Vertex-Basion height=135.66+/-6.56 mm; Eurion-Eurion width=141.17+/-5.19 mm; Glabella-Opisthocranion length=181.94+/-6.40 mm. On the midline T1-weighted sagittal image, all median craniometric landmarks can be individualized and the Glabella-Opisthocranion length, Vertex-Basion height and parenchyma indices can be calculated. Craniometric points and measurements between these points can be estimated with a standard cerebral MRI examination, with results that are similar to anthropometric data.