Paolo Perrini

Emerging Concepts in the Treatment of Intracranial Aneurysms: Stents, Coated Coils, and Liquid Embolic Agents

ENDOVASCULAR TECHNIQUES FOR the treatment of intracranial aneurysms are rapidly evolving. Modifications of more traditional coils have been introduced. Such modifications include newer coils coated with various polymers to increase both coil thrombogenicity and degree of aneurysm packing. In addition, newer coil designs aimed at improving the conformability of the coil to the aneurysm have been used with promising preliminary results. The availability of a newer generation of stents specifically designed for intracranial navigation allows for more effective treatment of aneurysms with wide necks, which usually have been considered unsuitable for optimal endovascular treatment. Endovascular alternatives to coil embolization, such as liquid embolic materials, also have been explored for the treatment of intracranial aneurysms, with varying results. We summarize the rationale for use of these newer devices and early clinical experiences. Areas of current research and future directions of endovascular aneurysm treatment also are discussed.

Extra-arachnoidal cranio-cervical decompression for syringomyelia associated with Chiari I malformation in adults: technique assessment.

SummaryBackground. The osteo-dural decompression of the cerebellar tonsils at the cranio-cervical junction is generally considered the most effective treatment for syringomyelia-Chiari I complex. However much controversy concerning a great number of surgical adjuvants to the standard bony decompression is still present. In this work an extra-arachnoidal cranio-cervical decompression (CCD) without duroplasty is described and the surgical results are reported. Method. Between 2000 and 2005, 24 adult patients underwent surgery for symptomatic syringomyelia-Chiari I complex not associated with hydrocephalus. In all cases, the surgical procedure consisted of a limited suboccipital craniectomy and laminectomy of C1 (when necessary C2 as well) followed by dural opening leaving the arachnoid membrane intact. The dura mater is left open and stitched laterally to the muscles. Findings. With a mean clinical long term follow-up of 44 months (range, 12–78 mo), neurological disturbances improved in 21 of 24 patients (87.5%) as result of extra-arachnoidal CCD. The postoperative complications occurred when the arachnoid was accidentally violated (4 cases, 16.6%). The complications included aseptic meningitis (one patient), nucal pseudomeningocele (two patients) and postoperative hydrocephalus requiring a ventriculoperitoneal shunt (one patient). Finally, one patient received an additional C2 laminectomy in order to obtain symptoms improvement and syrinx shrinkage. Postoperative MRI studies demonstrated that the syrinx decreased in size or collapsed in 20 patients (83.3%) and stabilized in 4 (16.7%). Conclusions. The extra-arachnoidal CCD is a safe and effective treatment for syringomyelia associated with Chiari I malformation in adults without intraoperative evidence of adhesive arachnoiditis. However a larger number of patients and longer follow-up will be necessary to determine the efficacy of extra-arachnoidal CCD.

Transoral approach and its superior extensions to the craniovertebral junction malformations: surgical strategies and results.

OBJECTIVE To review our experience with the surgical management of craniovertebral junction malformations, focusing on the selection of surgical approach, management of the associated Chiari malformation, and postoperative instability. METHODS During a 7-year period (May 2000–May 2007), 34 patients with a mean age of 55 years (age range, 32–75 years) underwent transoral surgery for fixed or nearly fixed ventral compression at the craniovertebral junction caused by basilar invagination and/or atlantoaxial dislocation. Chiari malformation was detected in 13 patients. The most common presenting signs were motor deficits (88%), followed by sensory loss (35%). All patients but one who had posterior stabilization performed elsewhere underwent single-stage anterior decompression and posterior occipitocervical fixation. Adjuncts to the transoral approach were tailored to the local anatomy (severity of basilar invagination, extent of mandibular excursion) found in each patient. Posterior fossa decompression was performed in 3 patients with Chiari malformation. RESULTS Thirty-one patients were alive at the time of the last follow-up evaluation (average, 3.7 years; range, 0.5–7.5 years). Of the 28 surviving patients admitted with preoperative motor impairment, 24 patients (86%) improved at least 1 Nurick grade, whereas the grade did not change in 4 (14%) patients. There were 2 (6%) perioperative deaths, and 1 other patient died subsequently of causes unrelated to surgery. Surgical morbidity was 18% and included dural laceration, cerebrospinal fluid leak with meningitis, malocclusion, oral wound dehiscence, and occipital wound infection. Delayed instability occurred in 1 patient because of cranial settling of the C2 vertebral body. CONCLUSION Successful decompression of the abnormal craniovertebral junction requires extensive preoperative evaluation, appropriate tailoring of the operative approach, and an adequate learning curve. Transmaxillary approaches are useful adjuncts to the transoral approach in patients with severe basilar invagination or in cases of limited jaw mobility. Anterior decompression has been proven effective in relieving obstruction of the subarachnoid space at the foramen magnum in most patients with associated Chiari malformation.

Acute external hydrocephalus complicating craniocervical decompression for syringomyelia–Chiari I complex

The occurrence of subdural cerebrospinal fluid collections and ventricular dilatation (external hydrocephalus) after foramen magnum decompression is extremely rare. The authors report on a 37-year-old man who developed symptomatic subdural fluid collections (SFC) after uncomplicated foramen magnum decompression for Chiari I–syringomyelia complex. Postoperative magnetic resonance imaging revealed a supratentorial SFC with prominent midline shift. In addition, bilateral infratentorial SFCs extending supratentorially through the tentorial notch, pseudomeningocele and initial shrinkage of the syrinx were observed. Few days after evacuation of supratentorial collection, the patient experienced increasing headache and a computerized tomography scan demonstrated a contralateral subdural collection as well as ventricular dilatation. A programmable ventriculoperitoneal shunt was placed with resolution of supratentorial collection and progressive improvement of infratentorial collections and pseudomeningocele. Although previous reports described the occurrence of extra-axial fluid collections and hydrocephalus after foramen magnum decompression for Chiari malformation, to our knowledge, this is the only report of acute external hydrocephalus after foramen magnum decompression requiring urgent evacuation of SFC in order to reduce the mass effect.

Radiation leukoencephalopathy associated with moderate hydrocephalus: intracranial pressure monitoring and results of ventriculoperitoneal shunting

Abstract. Delayed neurological sequelae of radiotherapy have several manifestations; leukoencephalopathy is one of the most common. Pathogenetic relationships between radiation leukoencephalopathy and other findings of diffuse radiation injury (brain atrophy and progressive ventriculomegaly) are not well defined. Moreover, no guidelines have been established for the treatment of hydrocephalus when associated with radiation leukoencephalopathy. Our study reportsintracranial pressure (ICP) monitoring in two patients with radiation leukoencephalopathy with moderate hydrocephalus. High intraventricular mean pressure and high peaks were found, and marked improvement of clinical status after shunting was achieved. This study, although restricted to only two patients, shows that ventriculoperitoneal shunting insertion is useful in radiation-induced hydrocephalus, when ICP monitoring detects high mean pressure. A hypothesis is advanced concerning radiation-induced hydrocephalus with high ICP, emphasizing periventricular astrocytosis and its connections with cerebral compliance.

SYRINGOPLEURAL SHUNT AS A RESCUE PROCEDURE IN PATIENTS WITH SYRINGOMYELIA REFRACTORY TO RESTORATION OF CEREBROSPINAL FLUID FLOW

OBJECTIVESyringomyelia should be treated by reconstruction of the subarachnoid space and restoration of cerebrospinal fluid homeostasis. Direct intervention on the syrinx is a difficult choice and should be considered a rescue procedure. Data in the literature examining the various options are scanty, with generally unsatisfying results. We report our experience with shunting of the syrinx into the pleural space. METHODSTwenty patients with syringomyelia refractory to cerebrospinal fluid flow restoration underwent a procedure for placement of a syringopleural shunt between 1998 and 2008. Modified Japanese Orthopaedic Association Scale scores and magnetic resonance imaging were available for each patient preoperatively and at the latest follow-up evaluation. A 2-tailed Wilcoxon signed-rank test was used for statistical analysis. Complications related to the operative procedure and to hardware failure were noted. RESULTSNineteen patients were available for follow-up with a mean duration of 37.5 (standard deviation, 31.1) months. The condition of 1 patient deteriorated, 2 remained stable, and the remainder improved. The overall mean improvement on the Modified Japanese Orthopaedic Association Scale was 19.5% (95% confidence interval, 8.5–30.5). The median improvement was 4 points on the 17-point scale. Results were statistically significant (P < 0.001). Follow-up magnetic resonance imaging showed syrinx collapse in 17 cases and marked shrinkage in 2 cases. Except for 1 case of meningitis followed by fatal pulmonary embolism, no significant complications were noted. CONCLUSIONA syrinopleural shunt should, in our view, be the syrinx diversion procedure of choice. More series of institutional experiences with a homogeneous approach would be helpful to verify this recommendation.

Three-dimensional microsurgical anatomy of cerebellar peduncles

The microsurgical anatomy of cerebellar peduncles and their relationships with neighbouring fasciculi were investigated by using a fibre dissection technique. As the dissection progressed, photographs of each progressive layer were obtained and stereoscopic images were created using the 3D anaglyphic method. These findings provided the anatomical basis for a conceptual division of cerebellar peduncles into segments. The middle cerebellar peduncle (MCP) was divided into two segments: cisternal and intracerebellar segments. The inferior cerebellar peduncle (ICP) was divided into three segments: cisternal, ventricular and intracerebellar segments. The superior cerebellar peduncle (SCP) was divided into three segments: intracerebellar, intermediate and intrategmental segments. The fibre dissection technique disclosed a constant course of peduncular fibres inside the white core of the cerebellum. The pontocerebellar fibres of the MCP pass over and laterally to the bundles of the ICP and SCP. The centripetal fibres of the ICP wrap around the radiation of the SCP and the dentate nucleus, directed towards the cortex of the vermis. The centrifugal bundle of the SCP ascends towards the mesencephalon where it sinks passing below the fibres the lateral lemniscus. The knowledge gained by studying the intrinsic anatomy of the cerebellum is useful to accomplish appropriate surgical planning and, ultimately, to understand the repercussions of surgical procedures on the white matter tracts in this region.

Second surgery for recurrent glioblastoma: A concise overview of the current literature

Optimal treatment for recurrent glioblastoma continues to evolve. Currently, however, there is no consensus in the literature on the role of reoperation in the management of these patients, as several studies provide evidence for a longer overall survival in selected patients with recurrent glioblastoma who underwent second surgery and other studies report a limited impact of second surgery in the clinical course. In this paper, a review of the current literature was performed to analyze the role of reoperation in patients with recurrent glioblastoma and to report the overall survival from diagnosis, progression-free survival and quality of life. Using PubMed and Ovid Medline databases, we performed a review of the literature of the last seven years, finding a total of 28 studies and 2279 patients who underwent second surgery, that were included in the final analysis. The median overall survival from diagnosis and the median survival from second surgery were 18.5 months and 9.7 months, respectively. Extent of resection at reoperation improves overall survival, even in patients with subtotal resection at initial operation. Preoperative performance status and age are important predictors of a longer survival, reason why younger patients with a good preoperative performance status could benefit from reoperation.

Malignant transformation of intramedullary melanocytoma: case report.

OBJECTIVEMeningeal melanocytomas are low-grade primary melanocytic tumors with benign histological features and a favorable clinical prognosis. Transition from meningeal melanocytoma to primary melanoma of the central nervous system is exceptionally rare, with only 5 cases having been previously reported. Here, we discuss a case of malignant transformation of an intramedullary melanocytoma to primary melanoma and review the pertinent literature. CLINICAL PRESENTATIONA 79-year-old woman presented with progressive paresis in the lower limbs followed by sphincter dysfunction. Magnetic resonance imaging scans disclosed an intramedullary lesion located at the T10–T11 level. INTERVENTIONThe patient underwent subtotal resection of an intermediate-grade melanocytoma. Two years later, the tumor recurred locally, and the patient underwent additional surgery to remove the intramedullary mass. The histological findings of the tumor were consistent with an intramedullary malignant melanoma. CONCLUSIONThe malignant transformation of melanocytic tumors of the central nervous system may occur years after surgical treatment, and its incidence remains unknown. Emphasis should be placed on the importance of careful and continued follow-up monitoring of the tumor.

Enterogenous cysts of the cerebellopontine angle: short review illustrated by two new patients

SummaryIntracranial enterogenous cysts are an uncommon entity rarely found in the midline within the posterior cranial fossa. The occurrence of an enterogenous cyst in the cerebellopontine angle is exceptional. We present two new cases of cerebellopontine angle (CPA) enterogenous cysts and review the literature to clarify the diagnosis and the management of these lesions.Eighteen cases of CPA intradural enterogenous cysts have been reported to date, including the two cases presented in this article. All of them were symptomatic and underwent surgical treatment. After surgery, the symptomatic recurrence occurred in 31% of the patients, most of which had partial excision. Considering our patients and the published cases in the literature we suggest that the aim of surgery should be total removal of cyst and its content whenever possible. When partial resection of the cyst is performed, we recommend long-term clinical and neuroradiological follow-up.