Anisotropic constitutive equations and experimental tensile behavior of brain tissue.

The present study deals with the experimental analysis and mechanical modeling of tensile behavior of brain soft tissue. A transversely isotropic hyperelastic model recently proposed by Meaney (2003) is adopted and mathematically studied under uniaxial loading conditions. Material parameter estimates are obtained through tensile tests on porcine brain materials accounting for regional and directional differences. Attention is focused on the short-term response. An extrapolation of tensile test data to the compression range is performed theoretically, to study the effect of the heterogeneity in the tensile/compressive response on the material parameters. Experimental and numerical results highlight the sensitivity of the adopted model to the test direction.

Intraventricular streptokinase infusion in acute post-haemorrhagic hydrocephalus.

Neonatal post-haemorrhagic hydrocephalus is a clinical condition with a high mortality and long-term morbidity. Its clinical management is difficult and not well standardized. We describe the case of a term baby suffering from acute intracranial hypertension caused by an intraventricular and thalamic haemorrhage. In this case, the external ventricular drain inserted to control intracranial pressure was ineffective because of repeated obstructions due to blood clots. Continuous intraventricular infusion of streptokinase of 20,000 U/day allowed quick lysis of the clots, drainage of the cerebrospinal fluid and relief from the coma. Although it did not prevent a permanent ventriculoperitoneal shunt, we obtained reabsorption of the intraventricular haemorrhage without rebleeding complications. We suggest the use of low-dose fibrinolytic infusion through an external drain for the treatment of acute intracranial hypertension following intraventricular haemorrhage in term infants.

Craniosynostosis: surgical treatment during the first year of life.

Out of 276 children with craniosynostosis operated on in a 9 year period, 231 were operated on under 1 year of age. According to the sutures involved in the process of early fusion, two groups of infants were individuated. Patients belonging to the first group were characterized by the involvement of the sagittal suture, while infants of group II presented with a synostosis of the anterior or posterior sutural complex. Two different techniques were required for the 2 groups of subjects, the first of them being mainly based on linear craniectomies, the second requiring more complex reconstructive surgical procedures. The morbidity, mortality and recurrence rates of the series were low, demonstrating that infants can tolerate the procedure as well as older children. The advantage of the early treatment consists of a better cosmetic result with a more physiological growth of faciocranial skeleton.

Combined management of intracranial vascular malformations in children.

UNLABELLED: We have reviewed 39 cases of intracranial vascular malformations, observed in the Section of Paediatric Neurosurgery of the Catholic University of Rome between 1980 and 1995 (age 1-15 years). Diagnosis was of parenchimal AVM in 26 cases, in 7 cases of AVM of the Galen region, in 5 cases of dural AVM and in 1 case of venous angioma. RESULTS AND CONCLUSIONS: Haemorrhage was the prevalent clinical onset in patients with parenchimal AVMs (57.7% of cases). Only one patient with a Galen region AVM presented cardiovascular symptoms, while 2/5 children observed for a dural AVM complained a congestive heart failure. Total surgical excision was performed in 17 of the 26 patients with parenchimal AVMs; moreover surgery was combined with preoperative endovascular embolization in 2 cases and with radiosurgery in 1 patient; we think that surgery is still the treatment of choice in patients with parenchimal AVMs. Endovascular treatment and radiosurgery have mainly an adjuvant role; nevertheless we agree that a preoperative endovascular management of parenchimal AVMs reduces the surgical risk, especially in cases of huge AVMs or AVMs localized in eloquent areas of the brain. Radiosurgery may be an alternative choice for complex or deeply sited AVMs; however in most cases, a combination with surgery or endovascular treatment is necessary to reduce the "target" size. AVM embolization was the only treatment in 2 of the 6 cases of dural AVMs; dural AVM embolization was combined with surgery in 1 case. Endovascular AVM exclusion is the treatment of choice in these patients. Surgery may be combined with endovascular treatment in case of a partial persistence of the AVM, or if signs of revascularization are present on control angiography. A conservative management is justified in patients with carotido-cavernous fistulae; in fact a complete spontaneous thrombosis is very frequent in these cases. A high rate of cardiovascular symptoms is reported in patients with Galen region AVMs diagnosed in the 1st year of life, but only 1 of our patients complained of congestive cardiac symptoms. Surgical treatment of Galen region AVMs is associated with a high morbidity and mortality. Actually a transarterial embolization of afferent vessels represents the treatment of choice in these patients; it can be combined with transvenous approach in case of complex AVMs and/or a non complete AVM exclusion.

Accessory lower limb in a newborn with multiple malformations.

Accessory lower limbs are rare anomalies that are associated with other severe malformations. The authors describe a case of this type and discuss the pathogenetic and classification problems surrounding these malformations in the light of the limited number of the other cases reported in the literature.

[Cerebral Doppler ultrasonography in newborn infants]. / Utilizzazione dell'eco-Doppler cerebrale in epoca neonatale.

Following the first study of Bada et al. (1979), Doppler assessment of cerebral blood flow has increasingly been used in newborn infants, matching the technical progress in the available equipment. The experience gathered in recent years has confirmed that Doppler US is a reliable and reproducible examination while precising the limitations and the methodology to be followed in order to prevent gross errors of assessment and interpretation. The interest this procedure has arisen, among other things, stems from being noninvasive and feasible at the patient's bed. These features enable its repeated use in newborn infants in poor clinical condition. The diagnostic and prognostic role of Doppler velocimetry has been shown in a number of neonatal diseases and the cerebral hemodynamics has been assessed in physiologic conditions as well as after drug administration. The most common equipment used in newborn infants is at present Duplex Doppler consisting of a pulsed Doppler combined with bidimensional scanner, which, with visualization of study arteries, enables precise positioning of sample volume and correction of the ultrasonic angle of incidence with respect to the direction of blood flow in the examined vessel. In this report, after a survey of the techniques and modalities of cerebral Doppler examination in newborns, a review of the present state of the art, in neonatal cerebral as well as extracranial disease, is presented.

[Postprandial and postural dyspnea: a clinical sign of intraperitoneal pseudocyst in patients with hydrocephalus and ventriculo-peritoneal shunt]. / Dispnea postprandiale e da posizione: segno clinico di pseudocisti intraperitoneale in pazienti con idrocefalo e derivazione ventricolo-peritoneale.

The surgical treatment of hydrocephalus has been greatly improved by the techniques of ventriculo-peritoneal shunting. Several complications may however occur following these operative procedures. Most of the complications are related to the distal end of the shunt device and include obstruction of intraperitoneal catheter, development of inguinal hernia or hydrocele, perforation of viscera. Many observations have been dedicated to these pathological findings, due to their frequency and the relatively easy diagnosis. Intraperitoneal pseudocysts are also a known complication of ventriculo-peritoneal shunts. Owing to their relative rare incidence and the aspecificity of their clinical presentation, this last type of complication has received a minor consideration. In the present report the authors describe two cases of intraperitoneal pseudocysts clinically manifested by the occurrence of postprandial dyspnea and hiccupping, without any apparent sign of CSF shunt device dysfunction.

Longitudinal assessment of visual development in non-syndromic craniosynostosis: a 1-year pre- and post-surgical study.

OBJECTIVE: to investigate visual function pre- and post surgery in children with single-suture non-syndromic craniosynostosis DESIGN: Twenty-nine infants (12 with sagittal synostosis, 10 with trigonocephaly and 7 with anterior plagiocephaly) were longitudinally evaluated using a battery of tests assessing various aspects of visual function, including ocular behaviour, acuity, visual fields and fixation shift. All infants were assessed before surgery and 2, 6 and 12 months after surgery. RESULTS: Before surgery only 16% of infants had completely normal visual function, while on the assessment performed 12 months after surgery, the number with normal results on all the tests increased to 65%. The only abnormalities found 12 months after surgical correction were mainly found on abnormal oculomotor behaviour in infants with plagiocephaly. CONCLUSION: Abnormalities of visual function were not frequent in infants with non-syndromic craniosynostosis who underwent surgical correction. Approximately half of the patients had some visual abnormalities before surgery, which subsequently improved, showing a delayed visual maturation rather than persistent abnormalities.

Visual function in infants with non-syndromic craniosynostosis.

The aim of this study was to assess various aspects of visual function in children with single-suture, non-syndromic craniosynostosis. Thirty-eight infants (28 males, 10 females; age range 3.5-13mo, mean age 7mo, 11 with plagiocephaly, 12 with trigonocephaly, and 15 with scaphocephaly), were assessed with a battery of tests specifically designed to assess various aspects of visual function in infancy. Thirty-two of the 38 infants had at least one abnormality on one of the aspects of visual function assessed. Abnormal eye movements were found in eight infants of the whole cohort and were mainly found in infants with plagiocephaly (6/11), who also had frequent visual field abnormalities (5/11). In contrast, fixation shift, an aspect of visual function related to the integrity of parietal lobes, was more frequently abnormal in patients with scaphocephaly. Our results suggest that the presence and severity of visual impairment is related to the type of craniosynostosis. Follow-up studies after surgical correction are needed to evaluate the possible beneficial effects of reconstructive surgery on visual function.

Nosographic identification and classification of plagiocephaly.

A classification of anterior plagiocephaly is proposed by the authors on the basis of the clinical and radiological findings analyzed in a series of 28 subjects less than 1 year old. Three main patterns of the anomaly have been identified. Type I anterior plagiocephaly is characterized by unilateral flattening of the frontal bone and elevation of the superior orbital ridge without deviation of the nasal pyramid. The vomer and petrous bones maintain a normal position. In type II anterior plagiocephaly, the frontal and orbital anomalies are accompanied by contralateral deviation of the nasal pyramid and homolateral anterior displacement of the petrous bone. A deviation of the sphenobasilar bone is associated with the above regard to the anomalies in type III anterior plagiocephaly. The three types of this particular form of craniosynostosis differ with difficulties involved in surgical management and outcome.

Early diagnosis and surgical indication in craniosynostosis.

9 children, presenting with clinical symptoms of craniosynostosis, and 4 with microcrania underwent calvaria bone scanning and a lumbar subarachnoid constant-infusion manometric test as integrating procedures for the diagnosis and surgical indication. In all the patients with craniosynostosis, calvaria bone scanning revealed the pathological sutures as areas of diminished or absent radionuclide accumulation, while a normal isotope uptake was observed at all the cranial sutures in the children with microcrania. A biphasic response to the infusion test, with an early rapid increase in the intracranial pressure and a late compensation, characterized 8 of the 9 children with craniosynostosis. The response to the infusion test was normal in all the cases with microcrania and in 1 child regarded as affected with coronal synostosis on the grounds of clinical and calvaria bone scanning findings.

Fibrous dysplasia of the skull in children.

Early diagnosis of skull fibrous dysplasia in children is relatively easy, based on a history of painless progressive bony bulging. The therapeutic approach is still controversial, due to the benignity of the lesion. However, the clinical course may be unpredictable, with sudden appearance of symptoms, some of which can be important and irreversible. In pediatric patients, the possibility that an early surgical correction might positively interfere with the natural history of the lesion has to be evaluated by taking into account the obvious difficulties that will be encountered in reconstructing the skull after a wide excision of the pathologic bone. In the present report, we describe our personal experience on the surgical treatment of 9 children, ranging in age between 7 and 14 years. The patients were subdivided into two groups, according to the localization and extent of the disease. Patients in group 1 presented an involvement of the hair-covered cranium and/or the fronto-orbital region. Group 2 patients presented with a multizonal involvement of the skull, including the central cranial base (pterygoid, sphenoid, petrous and mastoid bone). The different surgical options, chosen for the two groups of patients, are discussed, together with the technical methodologies utilized, the cosmetic results and the long-term follow-up.

Metopic synostosis: in favour of a "simplified" surgical treatment.

Metopic synostosis is a relatively simple form of craniosynostosis, resulting from premature fusion of the metopic suture. In this pathology different degrees of dysmorphia of the anterior cranial fossa and the presence of associated anomalies of the skull might enable specific subgroups to be identified. Since most functional and cosmetic anomalies benefit from early surgical treatment, over the last few years neurosurgeons have been forced to elaborate less drastic, but nonetheless effective, surgical techniques. In the present report we analyze the surgical results obtained in a series of 62 infants with trigonocephaly operated on within their 1st year of life. Patients were subdivided into two groups (group I: 8 patients; group II: 54 patients) according to the specific dysmorphic characteristics of the frontal bone and anterior cranial fossa, and the presence of compensatory deformities affecting the anterior cranial base and temporo-parietal region. All the patients were treated using one of two relatively simple surgical techniques (procedure A: inversion of two hemifrontal bone flaps--48 cases; procedure B: the "shell" operation--14 cases). Both surgical procedures appeared to be effective, allowing adequate functional and cosmetic correction of the cranial deformity. In patients operated on following procedure B surgical time and blood loss were dramatically reduced. Long-term outcomes were satisfactory in all cases, irrespective of the surgical technique used. In the group II patients, however, progressive normalization of the interorbital distance was constantly observed, suggesting a different degree of stenotic involvement at the level of the anterior cranial base in these patients.

[Metopic craniosynostosis. Surgical results in 35 surgically treated cases under 1 year of age]. / Craniosinostosi metopica. Risultati chirurgici in 35 casi operati sotto l'anno di età.

The clinical features, the diagnostic findings and the surgical results obtained on 35 children, under 1 year of age, operated on because of an early synostosis of the metopic suture are presented. In 79% of cases, the diagnosis was obvious at birth. A M/F ratio of 2.0 was observed in this series. Associated malformations were recorded in eleven patients (30.5%). The surgical procedure consisted of bilateral frontal craniectomy, opening of the roof of the orbit, advancement of the superior orbital margin, and repositioning of the frontal flaps after 180 degrees rotation. The cosmetical correction was satisfactory even in the immediate postoperative period. No mortality was recorded. The surgical correction was followed by a normal psychomotor development in 33 cases; delayed milestones were recorded in 2 children in whom the metopic synostosis was part of a complex malformative syndrome. On the grounds of our results, the young age of the patients at the operation should not be regarded as an obstacle to the immediate surgical correction; in our advice, the early correction results also in better functional and cosmetic long-term outcomes.

A survey of the first complication of newly implanted CSF shunt devices for the treatment of nontumoral hydrocephalus. Cooperative survey of the 1991-1992 Education Committee of the ISPN.

The results of an international multicenter study concerning the first complication of newly implanted cerebrospinal fluid shunts in nontumoral hydrocephalus are the subject of the present report. The authors have collected information on 773 cases from four continents. In particular, the following data were evaluated in relation to the general incidence of complications recorded in the first follow-up year: the patient's age at the operation, the etiology of hydrocephalus, the type of CSF shunt device used, and the modality of the surgical procedures. The overall complication rate in the series was 29%. Age and etiology of hydrocephalus appear to play a major role in influencing the complication rate; on the other hand, the choice of a specific CSF shunt device seems to be less important in this respect.

Spontaneous regression of a symptomatic pineal cyst after endoscopic third-ventriculostomy.

With the advent of modern diagnostic tools for neuroimaging, the incidental detection of pineal cysts in asymptomatic subjects has increased. Only rarely do pineal cysts present with the clinical signs and symptoms of increased intracranial pressure or with neurological deficits in relation to compression and distortion of the adjacent nervous structures and cerebrospinal fluid pathways. While asymptomatic cysts are considered to be normal variants for which no further investigations are usually required, surgical treatment is suggested for symptomatic cysts, with the goal of eliminating the block in the cerebrospinal fluid circulation and/or the mass effect exerted by the lesion. In this report we describe a pediatric case of symptomatic pineal cyst, revealed by repeated episodes of headache caused by secondary obstructive hydrocephalus. Following an endoscopic third-ventriculostomy, serial magnetic resonance imaging studies demonstrated that not only had the ventriculomegaly resolved but also that the pineal cyst had regressed over time. A to-and-fro movement of fluid through the cyst wall, the direction of which depends on the equilibrium existing between the inner pressure of the cyst and the outer cerebrospinal fluid pressure, is suggested as a possible mechanism accounting for this unexpected result--to our knowledge, the first reported in literature.

Blood salvage in craniosynostosis surgery.

In the history of surgery, every single step forward in the development of complex surgical techniques has been sustained by the acquisition of more reliable and effective methods for controlling hemostasis. For many years, in fact, uncontrolled hemorrhages, together with infections, represented the most deadly hazard of surgical procedures. In the last century, technical advances in surgical hardware and homologous blood transfusions have been utilized to counteract operative and postoperative anemia and hypovolemia. At the end of this millennium, however, new revelations about the infective and noninfective risks of allogeneic blood transfusions have led to a new acceleration in patients' and physicians' demands for autologous transfusions and more efficient blood conservation techniques. Specific surgical protocols, based on the preoperative administration of r-HuEPO, preoperative autologous blood donation, acute preoperative normovolemic hemodilution and intraoperative blood salvage techniques, have been designed by pediatric neurosurgeons to minimize the exposure of patients affected by craniosynostoses to allogeneic blood and blood components even when the surgical procedure is to be realized at an early age. In spite of the evolution expected in this area in the immediate future, the implementation of these blood concentration methodologies may prove to be highly effective only when associated with a concerned attitude of the surgeon toward blood-sparing intraoperative strategies.

[Craniostenosis. Analysis of 161 cases surgically treated during the first year of life]. / Craniostenosi. Analisi di 161 casi operati nel primo anno di vita.

One hundred-sixty-one cases of children operated on for craniostenosis in the first year of life at the Neurosurgical Department of the Catholic University of Rome in the period 1982-1986 are presented. The average age at diagnosis was 6 months and at operation 7.4 months. The patients considered in the present study were subdivided into two groups according to the prevalent involvement of sagittal suture or of the anterior sutural group (coronal metopic, spheno-frontal and spheno-palatine sutures). In fact, these two groups differ considerably not only in the characteristics of the pathological process of early fusion of the cranial sutures, but also in the technique required for surgical correction. Four children with premature fusion of all cranial sutures are considered separately. Congenital malformations of the bone structures or changes in ocular motility were presented in 7.9% of 63 patients with sagittal craniostenosis and in 14.7% of the group with premature fusion of the anterior cranial sutures. Surgical correction (linear craniectomies extended to the cranial base for the group with sagittal craniostenosis, craniectomies with advancement of the supraorbital margin and rotation of the bone operculum for the group with anterior craniostenosis) proved satisfactory in the great majority of cases. Postoperative morbidity was particularly low. Apart from postsurgical anaemia which required blood transfusion on the third day in 15.5% of operated patients, the only complications were transitory hyperpyretic states observed in 6.2% of cases. Only one child died for reasons related to the surgical procedure. The low postoperative mortality (0.6% of cases) and the low percentage of bone pathology recurrence (7.4%) compared with the results of other series involving older children, seem to indicate that the early surgical correction of bone malformations does not bear additional risk for the patient, permitting at the same time normal functional development of the brain and a more gradual morphological remodelling of the skull.

[Intracranial tumors in the 1st year of life]. / Tumori intracranici nel primo anno di vita.

The introduction of the new diagnostic tools for neuroimaging has resulted in the early recognition of congenital brain tumors. In the present report we describe 39 children, in whom the diagnosis of an intracranial tumor has been obtained during the first 12 months of life. These patients represent 14.4% of a pediatric population of 271 children with brain tumors, observed in the same period of time (11 years) in the Neurosurgical Institute of the Catholic University of Rome. Most of the tumors were located within the supratentorial compartment. Midline tumors were common. Sixteen children underwent the total removal of the tumor. Four infants could not be operated either because their poor general condition or the extension of the tumor. In one case, treatment was refused by the parents. The remaining children underwent the partial removal of the tumor, which was followed by chemotherapy (malignant tumors) or by serial neuroradiological examination (benign tumors), with the aim of postponing radiotherapy at the end of 2 years of age at least. The total mortality (surgical deaths: 7 cases) and deaths during the follow-up period (11 cases) was 38.5%. Out of the 24 surviving children, 8 (20%) are normal: 7 (17%) exhibit only minimal neurosurgical deficits; 9 (22%) are seriously handicapped. One child has been lost for the follow-up observation.