Pietro Spennato

Chiari malformation in craniosynostosis

IntroductionChiari malformation (CM) is a frequent finding in multisutural and syndromic craniosynostosis, occurring in 70% of patients with Crouzon’s syndrome, 75% with oxycephaly, 50% with Pfeiffer’s syndrome and 100% with the Kleeblattschädel deformity. The pathogenesis of this condition and rationale for treatment are still controversial.DiscussionSince its first description in 1972, several factors have been cited to play a role in inducing CM. In the light of recent publications, the roles of premature fusion of cranial vault and cranial base sutures, of congenital anomalies of the cerebellum and brain stem, of raised intracranial pressure, of venous hypertension and of hydrocephalus are reviewed. Evaluation and management of CM are also discussed.ConclusionChiari malformation appears to be an acquired and progressive condition that develops in the first months of life, because of a disproportion between hindbrain growth and an abnormally small posterior fossa, a consequence of the premature fusion of lambdoid and cranial base sutures. Venous hypertension caused by stenosis of the jugular foramen can also be present in these patients, resulting in intracranial hypertension and/or hydrocephalus. Careful MRI evaluation is recommended for the forms of craniosynostosis at a high risk of developing hindbrain herniation. The selection of posterior cranial vault expansion as the first surgical procedure is advocated. In selected cases, treatment of the posterior cranial deformity by occipital vault remodelling and treatment of the Chiari-like deformity by suboccipital decompression can be carried out using the same surgical procedure.

Application of neuroendoscopy to intraventricular lesions.

We present an overview of the history, development, technological advancements, current application, and future trends of cranial endoscopy. Neuroendoscopy provides a safe and effective management modality for the treatment of a variety of intracranial disorders, either tumoral or non-tumoral, congenital, developmental, and degenerative, and its knowledge, indications, and limits are fundamental for the armamentarium of the modern neurosurgeon.

Current state and future development of intracranial neuroendoscopic surgery

Since the introduction of the modern, smaller endoscopes in the 1960s, neuroendoscopy has become an expanding field of neurosurgery. Neuroendoscopy reflects the tendency of modern neurosurgery to aim towards minimalism; that is, access and visualization through the narrowest practical corridor and maximum effective action at the target point with minimal disruption of normal tissue. Transventricular neuroendoscopy allows the treatment of several pathologies inside the ventricular system, such as obstructive hydrocephalus and intra-/paraventricular tumors or cysts, often avoiding the implantation of extracranial shunts or more invasive craniotomic approaches. Endoscopic endonasal transphenoidal surgery allows the treatment of pathologies of the sellar and parasellar region, with the advantage of a wider vision of the surgical field, less traumatism of the nasal structures, greater facility in the treatment of possible recurrences and reduced complications. However, an endoscope may be used to assist microsurgery in virtually any kind of neurosurgical procedures (endoscope-assisted microsurgery), particularly in aneurysm and tumor surgery. Basic principles of optical imaging and the physics of optic fibers are discussed, focusing on the neuroendoscope. The three main chapters of neuroendoscopy (transventricular, endonasal transphenoidal and endoscope-assisted microsurgery) are reviewed, concerning operative instruments, surgical procedures, main indications and results.

Intracranial pressure monitoring and lumbar puncture after endoscopic third ventriculostomy in children.

OBJECTIVE:The aim of this study is to analyze changes in intracranial pressure (ICP) after endoscopic third ventriculostomy (ETV) performed in children affected by noncommunicating hydrocephalus. METHODS:ICP was continuously recorded for an average of 7 days in 64 children who underwent 68 ETVs for obstructive triventricular hydrocephalus of various etiology. In the first group (44 children), ETV was performed as the primary treatment; in the second group (20 children), the patients presented with shunt malfunction and underwent ETV and shunt removal. Three of the patients in the second group were reoperated for obstruction of the stoma: two were reoperated once and one was reoperated twice. RESULTS:ICP changes after ETV were not homogeneous and varied according to etiology: the highest values were observed in patients affected by posterior fossa tumors and the lowest values were seen in patients operated on during shunt malfunction and who had their shunt removed. After 31 procedures (45.6%), ICP remained normal (<20 mmHg) for the entire duration of the monitoring. After 37 procedures (54.5%), ICP was persistently high on Day 1 (mean, 29.7) and decreased very slowly in the subsequent days, remaining high for 2–9 days (mean, 4.5). After 20 of the 37 procedures with high postoperative ICP, patients presented symptoms of intracranial hypertension that resolved, in most of the cases, with one or two lumbar punctures. Lumbar puncture was noted to be effective in bringing about fast normalization of the ICP and resolution of the symptoms. In 13 patients (19.1%), ETV failed and a ventriculoperitoneal shunt was implanted. After four procedures, the stoma obstructed and the patients were treated, reopening the stoma. Postoperative ICP was not statistically significant higher in the patients in whom ETV failed. CONCLUSION:The high ICP observed in a group of patients in the early postoperative days is probably related to the slow permeation of the subarachnoid spaces by the cerebrospinal fluid flowing out of the third ventriculostomy. Management of intracranial hypertension after ETV remains a matter of controversy. The role of the lumbar puncture in the faster normalization of the ICP is examined in this article. By increasing the compliance and the buffering capacities of the spinal subarachnoid spaces, it probably decreases the cerebrospinal fluid outflow resistance from the ventricular system, facilitating the decrease of the ventricular volume and allowing faster permeation of the intracranial subarachnoid spaces. High postoperative ICP can account for persistent symptoms of intracranial hypertension and ventricular dilatation on computed tomographic scans after third ventriculostomy. A cycle of one to three lumbar punctures should always be performed in patients who remain symptomatic and who show increasing ventricular dilatation after ETV, before ETV is assumed to have failed and an extracranial cerebrospinal fluid shunt is implanted.

Hydrocephalus in aqueductal stenosis.

IntroductionThe sylvian aqueduct is the most common site of intraventricular blockage of the cerebro-spinal fluid. Clinical aspects, neuroradiological appearance, and treatment of hydrocephalus secondary to aqueductal stenosis are specific.MethodsAn extensive literature review concerning etiologic, pathogenetic, clinical, and neuroradiological aspects has been performed. Therapeutic options, prognosis, and intellectual outcome are also reviewed.ConclusionThe correct interpretation of the modern neuroradiologic techniques may help in selecting adequate treatment between the two main options (third ventriculostomy or shunting). In the last decades, endoscopic third ventriculostomy has become the first-line treatment of aqueductal stenosis; however, some issues, such as the cause of failures in well selected patients, long-term outcome in infant treated with ETV, and effect of persistent ventriculomegaly on neuropsychological developmental, remain unanswered.

Long-term results of a second endoscopic third ventriculostomy in children: retrospective analysis of 40 cases.

OBJECTIVETo evaluate retrospectively the operative findings and long-term results of a repeat endoscopic third ventriculostomy (ETV) in pediatric hydrocephalic patients readmitted after the first procedure with symptoms and/or signs of intracranial hypertension and/or radiological evidence of increased ventricular dilation and/or occluded stoma on follow-up radiological examinations. METHODSWe analyzed a series of 482 ETVs in pediatric patients from 2 Italian departments of pediatric neurosurgery. The clinical charts of 40 patients undergoing a second ETV were selected and reviewed retrospectively. The pre- and postoperative radiological findings and operative films were analyzed retrospectively. RESULTSForty patients underwent a total of 82 ETVs. Thirty-eight patients were operated on twice and 2 were operated on 3 times. During the second procedure, the stoma was found to be closed in 28 patients without underlying adhesions, to be open but with significant arachnoid adhesions in the prepontine cistern in 8 patients, to be open without adhesions in 2 patients, to have a pinhole orifice in 1 patient, and to be closed with underlying adhesions in 1 patient. The second procedure allowed reopening of the stoma or lysis of the arachnoid adhesions in 35 patients and was abandoned in 3 patients because of extensive arachnoid adhesions or because the stoma was found to be wide open (2 patients). In 30 patients (75%), the second ETV was effective, and the 2 patients who underwent a third ETV remained shunt free. In 10 patients (25%), a ventriculoperitoneal shunt was eventually placed. Age younger than 2 years at the time of the first procedure and arachnoid adhesions in the subarachnoid cisterns observed during the second procedure are the main negative prognostic factors for the success of a second ETV. CONCLUSIONA second ETV can be performed with a reasonable chance of restoring patency of the stoma and avoiding placement of an extrathecal shunt. Every effort should be made to detect subarachnoid adhesions in the cistern on preoperative imaging study to select potential candidates and avoid unnecessary procedures.

Hydrocephalus in Dandy–Walker malformation

IntroductionEven if the first description of Dandy–Walker dates back 1887, difficulty in the establishment of correct diagnosis, especially concerning differential diagnosis with other types of posterior fossa CSF collection, still persists. Further confusion is added by the inclusion, in some classification, of different malformations with different prognosis and therapeutic strategy under the same label of “Dandy–Walker”.MethodsAn extensive literature review concerning embryologic, etiologic, pathogenetic, clinical and neuroradiological aspects has been performed. Therapeutic options, prognosis and intellectual outcome are also reviewed.ConclusionThe correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a “real” Dandy–Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

Hydrocephalus and spinal cord tumors: a review

IntroductionHydrocephalus secondary to intraspinal tumors is a well-known but rare condition since about 1% of patients with spinal cord tumors have various degrees of hydrocephalus at initial presentation.DiscussionThe mechanism of development of intracranial hypertension and hydrocephalus in patients with spinal cord tumor is not exactly known. The problematic aspects of this condition, with regard to clinical presentation and pathophysiology, are discussed and the relevant literature is reviewed. This uncommon association should always be kept in mind in the differential diagnosis of hydrocephalus of unknown etiology for three main reasons: the possibility of neurological deterioration if the patient is shunted prior tumor removal, the possibility to treat the hydrocephalus without shunting by simply removing the tumor, and the possible role of hydrocephalus as an early sign of intracranial metastasis in patients previously operated upon for removal of intramedullary gliomas. Due to the very slow evolution of the disease, a careful and close clinical and neuroradiological follow-up are essential for many years afterward. The presence of intracranial hypertension in a patient previously operated for a spinal tumor should be considered and investigated as an early sign of neoplastic intracranial seeding.

Grisel Syndrome Following Adenoidectomy: Surgical Management in a Case with Delayed Diagnosis

BACKGROUND Grisel syndrome is a nontraumatic rotatory subluxation of the atlantoaxial joint, following nasopharyngeal inflammation or ear, nose, and throat (ENT) procedures. The syndrome should be suspected in cases of persistent neck pain and stiffness, especially after ENT surgical procedures. The primary treatment of early detected Grisel syndrome is conservative. If conservative treatment fails to achieve a stable reduction or it is followed by neurologic symptoms, arthrodesis of the first and second cervical vertebrae is indicated. We report the case of a 9-year-old boy who developed Grisel syndrome after adenoidectomy and was treated with C1-C3 internal fixation and fusion. CASE DESCRIPTION A 9-year-old boy was referred to our hospital with a 3-month history of painful torticollis, which appeared 4 days after adenoidectomy. The patient underwent a neuroimaging study that documented the presence of atlantoaxial rotatory subluxation. The patient underwent C1-C3 internal fixation and fusion, using lateral masses and laminar and pars interarticularis screws. On the third postoperative day he was mobilized with a rigid collar. Postoperative computed tomography scans showed the resolution of rotational deformity and a solid fusion. CONCLUSION Early treatment of Grisel syndrome is of utmost importance to avoid neurologic complications and surgical intervention. In a patient with torticollis following ENT procedures, Grisel syndrome should be always suspected. In case of failure of conservative treatment or in case of delayed diagnosis, rigid C1-C2 or C1-C2-C3 fixation is a straightforward and valid surgical technique, even in children, because it provides immediate spinal stability in all planes at the atlantoaxial complex, avoiding the need for prolonged rigid external bracing.

Posterior fossa tumors in infants and neonates.

IntroductionManagement of posterior fossa tumors in infants and neonates is challenging. The characteristics of the young babies make surgery very difficult, sometimes precluding a safe complete removal.MethodsA review of the literature was undertaken to examine the incidence, histology, surgical aspects, and prognosis of posterior fossa tumors in the first year of life. Therapeutical strategies of the most frequent tumor types are also discussed in detail.ResultsHistology is dominated by tumors with aggressive behavior, such as medulloblastomas, atypical teratoid/rhabdoid tumors, and anaplastic ependymomas. The most important surgical considerations in small children are the small circulating blood volume; the poor thermoregulation; and incomplete maturation of the brain, of the skull, and of the soft tissue. Treatment toxicity is inversely related to the age of the patients. Radiation therapy is usually considered as contraindicated in young children, with few exceptions. Proton therapy is a promising tool, but access to this kind of treatment is still limited. The therapeutic limitations of irradiation render resection of this tumor and adjuvant chemotherapy often the only therapeutic strategy in many cases.ConclusionsThe overall prognosis remains dismal because of the prevalent aggressive histologies, the surgical challenges, and the limitations of adjuvant treatment. Nevertheless, the impressive improvements in anesthesiology and surgical techniques allow, in the vast majority of the cases, complete removal of the lesions with minor sequelae in high-volume referral pediatric centers.