Changes in Callosal Angle and Evans Index After Shunt Surgery in Patients with Idiopathic Normal Pressure Hydrocephalus.

OBJECTIVE: Idiopathic normal pressure hydrocephalus (iNPH) is a disease characterized by gait disturbance, cognitive impairment, and urinary incontinence. For those patients who do not respond to shunt surgery, it lacks objective radiologic findings for the diagnosis of shunt malfunction. Here we aimed to evaluate whether the Evans index and callosal angle change during a prospective long-term follow-up of patients with iNPH submitted to shunt surgery. METHODS: Clinical (NPH Japanese Scale) and radiologic (Evans index and callosal angle) data were collected pre- and postoperatively (3, 6, 12 and months) in 19 patients with iNPH. Imaging tests were evaluated by the same neuroradiologist during the follow-up. RESULTS: Patients had lower scores on the NPH Japanese Scale over time (P < 0.001). There was no significant difference among Evans index values during the follow-up (P = 0.24). Preoperative average callosal angle was 72 ± 15, which increased to 91 ± 18 in 6 months (P = 0.003). CONCLUSIONS: In this sample, patients with iNPH submitted to a programmable valve shunt had an increase in callosal angle concomitant to neurologic improvement. The Evans index did not change during follow-up.

Fetal neurosurgery.

Among fetal surgical procedures, neurosurgery stands out due to the number of cases and the possibility of developing new procedures that can be performed in the fetal period. To perform fetal neurosurgical procedures, there is a need for specialized centers that have experts in the diagnosis of fetal pathologies and a highly complex obstetrics service with specialized maternal-fetal teams associated with a pediatric neurosurgery center with expertise in the diverse pathologies of the fetus and the central nervous system that offers multidisciplinary follow-up during postnatal life. Services that do not have these characteristics should refer their patients to these centers to obtain better treatment results. It is essential that the fetal neurosurgical procedure be performed by a pediatric neurosurgeon with extensive experience, as he will be responsible for monitoring these patients in the postnatal period and for several years. The objective of this manuscript is to demonstrate the diagnostic and treatment possibilities, in the fetal period, of some neurosurgical diseases such as hydrocephalus, tumors, occipital encephalocele, and myelomeningocele.

The Hypoglossal Nerve.

The hypoglossal nerve is the 12th cranial nerve, exiting the brainstem in the preolivary sulcus, passing through the premedullary cistern, and exiting the skull through the hypoglossal canal. This is a purely motor nerve, responsible for the innervation of all the intrinsic tongue muscles (superior longitudinal muscle, inferior longitudinal muscle, transverse muscle, and vertical muscle), 3 extrinsic tongue muscles (styloglossus, hyoglossus, and genioglossus), and the geniohyoid muscle. Magnetic resonance imaging (MRI) is the best imaging exam to evaluate patients with clinical signs of hypoglossal nerve palsy, and computed tomography may have a complementary role in the evaluation of bone lesions affecting the hypoglossal canal. A heavily T2-weighted sequence, such as fast imaging employing steady-state acquisition (FIESTA) or constructive interference steady state (CISS) is important to evaluate this nerve on MRI. There are multiple causes of hypoglossal nerve palsy, being neoplasia the most common cause, but vascular lesions, inflammatory diseases, infections, and trauma can also affect this nerve. The purpose of this article is to review the hypoglossal nerve anatomy, discuss the best imaging techniques to evaluate this nerve and demonstrate the imaging aspect of the main diseases that affect it.