Pulsed radiofrequency energy device (PEAK plasmablade™) and CustomBone® Cranioplasty: an appealing surgical rendez-vous.

BACKGROUND: CustomBone® prosthesis is a widely recognized effective and successful technique for the reconstruction of cranial bone defects. Prior the cranioplasty implant, meticulous dissection within thick scar tissue is required. During this delicate surgical manoeuvre is vital to avoid damage to the skin flap itself and to the underlying cerebrovascular structures. We report our experience and potential applications of a novel, pulsed monopolar radiofrequency energy device (PEAK PlasmaBlade™, Medtronic plc). It reduced the incidence of post operativesubgaleal hematoma, the operative times and the intra operative blood loss following cranioplasty compared to the traditional scalpel and scissor dissection. METHODS: The authors present a one centre case series study to review the indications, safety and efficacy of the PEAK PlasmaBlade™ in adult patientsunderwent cranioplasty. Two surgical techniques for tissue dissection were compared: PEAK PlasmaBlade™ versus scalpel and scissor dissection (SSD). Treatment outcomes following each of these surgical approaches, relative to rate of post-operative subgalealhematoma formation, hospital admission, and operative times were compared. RESULTS: A total of 10 patients that had cranioplasty treatment were evaluated. In patients underwent scalp dissection with the PEAKPlasmaBlade™, we observed a reduction in the operative times, in the subgaleal hematoma formation and then in the hospital stay. CONCLUSION: PEAK PlasmaBlade™ revealed to be a safe and effective device in tissues dissection for cranioplasty implant. It provided reduction of the rate of subgaleal hematoma formation, operating times and less potential risk to damage cerebrovascular structures.

Can biomechanical analysis shed some light on aneurysmal pathophysiology? Preliminary study on ex vivo cerebral arterial walls.

BACKGROUND: The pathophysiology of cerebral aneurysm is complex and poorly understood, and it can have the most catastrophic clinical presentation. Flow dynamics is a key player in the initiation and progression of aneurysm. Better understanding the interaction between hemodynamic loading and biomechanical wall responses can help to add the missing piece on aneurysmal pathophysiology. In this laboratory study we aimed to analyze the effect of the application of a mechanical force to cerebral arterial walls. METHODS: Displacement control tests were performed on five porcine cerebral arteries. The test machine was the T150 Nanotensile. The stiffness variation with the increment of the strain level is modeled as the outcome of an isotropic hyperelastic material model. FINDINGS: Through the application of an axial force we obtained Stress/Strain curves that showed a marked isotropic hyperelastic behavior, characterized by an increasing of stiffness with the level of strain. This behavior of the cerebral arterial wall is different from the well-established behavior of other arterial vessel (as the aortic vessel) characterized by a marked anisotropic behavior. Additionally, the data scattering observed for higher values of the applied stress are related to different individual packing of collagen fibers that represent the load-bearing mechanics at higher level of the strain. INTERPRETATION: The data obtained by test in this paper represent a first step in our ongoing research about the mechanics of multi-axial loads on cerebral arterial walls, and in producing more comprehensive patient-specific calculations for potential applications on cerebral aneurysm management.

The Transcallosal Anterior Interfoniceal Approach: A Microsurgical Anatomy Study.

Objectives A plethora of surgical strategies have been described to reach deep-seated lesions situated within the third ventricle including the Rosenfeld, or transcallosal anterior interfoniceal (TAIF), approach. First introduced in 2001, it consists of a small callosotomy followed by the midline transseptal dissection of fornices to enter the roof of the third ventricle. The aim of this microsurgical anatomy study is to describe and show each stage of the surgical procedure, focusing on the possible trajectories to anatomical landmarks. Participants A total of 20 adult cadaveric specimens were used in this study. Using ×3 to ×40 magnifications, the surgical dissection was performed in a stepwise fashion, and the transcallosal anterior interforniceal approach was performed, analyzed, and described. Results In 5 specimens of 10, a cavum septum pellucidum was depicted. In 5 cases of 20 after the callosotomy ,the lateral ventricular cavities were reached. Different orientation of the microscope allowed us to define three surgical trajectories to visualize the region of interest without exposing important functional areas. Conclusion The TAIF represents a minimally invasive approach to the third ventricle; its tricky surgical steps make appropriate anatomical dissection training essential to become confident and skilled in performing this approach.

Emergency surgery in a patient with large spontaneous spinal epidural hematoma determining excellent neurological recovery: review of the literature.

STUDY DESIGN: Case report. OBJECTIVES: We report a case of a 75-year-old woman suffering from voluminous idiopathic spontaneous spinal epidural hematoma (SSEH) that was rapidly diagnosed and successfully treated. METHODS: Clinical presentation was characterized by sudden and intense back pain that rapidly evolved into plegia of the right leg and severe paresis of the left leg. Hypoesthesia below T6 and urinary retention were also present. Magnetic resonance imaging showed a significant posterior spinal compression from T6 through L3 caused by an epidural hematoma that involved 10 metameric levels, extending for ∼20 cm, with a maximum thickness of 1.6 cm from T12 to L1. RESULTS: Within 12 h, emergency decompressive laminectomy from T10 to L1 was performed, and evacuation of the hematoma was achieved. The postoperative course and neurological recovery of the patient were optimal. After discharge, the patient continued the rehabilitative treatment started during hospitalization, achieving an excellent functional outcome in 1 month. CONCLUSIONS: Spinal epidural hematoma (SEH) is a rare clinical finding that can occur following trauma or spontaneously (SSEH). We describe, to the best of our knowledge, the second most extensive idiopathic SSEH and the longest with involvement of the dorso-lumbar spine that had a excellent functional outcome due to emergency decompressive laminectomy, which is emphasized in the treatment of these rare pathologies.

Clinical analysis following lumbar interspinous devices implant: where we are and where we go.

STUDY DESIGN: Retrospective study. OBJECTIVES: We present our experience with patients treated with interspinous devices who are affected by neurogenic intermittent claudication (NIC) or lumbar disc herniation (LDH) where the interspinous system has been inserted following microdiscectomy. METHODS: This study included patients (n = 100) with NIC secondary to lumbar spinal stenosis (group 1), and patients (n = 100) with LDH (group 2) in whom the interspinous device has been implanted following radicular decompression in a period spanning 6 years. The latter have been compared with a homogenous group of patients (n = 100) where no interspinous system has been implanted following microdiscectomy (group 3). Clinical findings have been observed preoperatively and 3, 6, 12 months and every year post-operatively using dedicated questionnaires (Zurich Claudication Questionnaire, Visual Analog Scale and Oswestry Disability Index). RESULTS: Six years following surgical treatment, 85% of the patients of group 1 presented good improvement of symptoms and 90% of the patients referred satisfaction for surgery. Only few cases needed reoperation. In one case, the device was removed and in two cases, we changed the surgical strategy. Overall, patients of group 2 presented significantly less lumbar disc recurrences compared with group 3 (P < 0.05) and better clinical outcome when compared with the same group (P < 0.01). CONCLUSION: According to our features, interspinous systems showed significant and clinically meaningful improvements in pain and disability for up to 6 years. Furthermore, interspinous devices have shown better clinical outcome and less lumbar disc recurrences when associated with standard microdiscectomy. These data, however, need further studies and a longer period of follow-up.

Intramedullary spinal cord tumor presenting as the initial manifestation of metastatic colon cancer: case report and review of the literature.

STUDY DESIGN: Case reports and review of the literature. OBJECTIVE: Intramedullary spinal cord metastases (ISCMs) are rare type of central nervous system (CNS) involvement of systemic malignant tumors. Since the advent of new neuroradiological techniques, their detection have become increasingly diagnosed in recent years and, although somewhat controversial, surgical treatment has been considered a valid option. SETTING: Neurosurgical Clinic, Department of Clinic Neuroscience, University of Palermo, Italy. METHOD: The authors describe the case of a 61-year-old woman who was admitted presenting with progressive tetraplegia. Investigations revealed an intramedullary spinal cord lesion at the cervical level. Magnetic resonance imaging of the brain did not reveal other CNS metastatic lesions. RESULT: Patient underwent surgical treatment. The tumor was resected and the patient's neurologic deficits slowly improved. Histological examination of the lesion showed the typical features of a colon carcinoma metastasis. Patient was referred for proper oncological treatment but, unfortunately, she died of disseminated disease within 2 months. CONCLUSION: Although uncommon, spinal cord metastases should be considered in the differential diagnosis of ISCM in order to rationalize the decisional-making process and improve the quality of life for these patients.

Cerebral haemodynamic changes during propofol-remifentanil or sevoflurane anaesthesia: transcranial Doppler study under bispectral index monitoring.

BACKGROUND: Sevoflurane or propofol-remifentanil-based anaesthetic regimens represent modern techniques for neurosurgical anaesthesia. Nevertheless, there are potential differences related to their activity on the cerebrovascular system. The magnitude of such difference is not completely known. METHODS: In total 40 patients, treated for spinal or maxillo-facial disorders, were randomly allocated to either i.v. propofol-remifentanil or inhalational sevoflurane anaesthesia. Transcranial Doppler was used to assess changes in cerebral blood flow velocity, carbon dioxide reactivity, cerebral autoregulation and the bispectral index to assess the depth of anaesthesia. RESULTS: Time-averaged mean flow velocity (MFV) was significantly reduced after induction of anaesthesia in both sevoflurane and propofol-remifentanil groups (P<0.001). At deeper levels of anaesthesia, MFV increased in the sevoflurane group, suggesting an uncoupling flow/metabolism, whereas it was further reduced in the propofol-remifentanil group (P<0.001). Indices of cerebral autoregulation were reduced in patients with high-dose sevoflurane whereas autoregulation was preserved in patients anaesthetized with propofol-remifentanil (P<0.001). Higher CO(2) concentrations impaired cerebral autoregulation in the sevoflurane group but not in patients anaesthetized with propofol-remifentanil. CONCLUSIONS: Propofol-remifentanil anaesthesia induced a dose-dependent low-flow state with preserved cerebral autoregulation, whereas sevoflurane at high doses provided a certain degree of luxury perfusion.

Different methods for anatomical targeting.

AIM: Several procedures are used in the different neurosurgical centers in order to perform stereotactic surgery for movement disorders. At the moment no procedure can really be considered superior to the other. We contribute with our experience of targeting method. METHODS: Ten patients were selected, in accordance to the guidelines for the treatment of Parkinson disease, and operated by several methods including pallidotomy, bilateral insertion of chronic deep brain electrodes within the internal pallidum and in the subthalamic nucleus (18 procedures). INTERVENTIONS: in each patient an MR scan was performed the day before surgery. Scans were performed axially parallel to the intercommissural line. The operating day a contrast CT scan was performed under stereotactic conditions. MEASURES: after digitalization of the MRI images, it was possible to visualize the surgical target and to relate it to parenchimal and vascular anatomic structures readable at the CT examination. The CT scan obtained was confronted with the MR previously performed, the geometrical relation between the different parenchimal and vascular structures and the selected targets were obtained. Stereotactic coordinates were obtained on the CT examination. RESULTS: It was possible to calculate the position of the subthalamic nucleus and of the internal pallidum on the CT scan, not only relating to the intercommissural line, but considering also the neurovascular structures displayed both on the MRI and the CT scans. CONCLUSION: The technique that our group presents consist in an integration between information derived from the CT and the MR techniques, so that we can benefit from the advantages of both methods and overcome the disadvantages.

Assistance of intraoperative microvascular Doppler in the surgical obliteration of spinal dural arteriovenous fistula: cases description and technical considerations.

BACKGROUND: Intraoperative microvascular Doppler may be valuable in assisting in the surgical obliteration of dural arteriovenous fistula of the spinal cord. It enables identification, through flow spectrum analysis, of the anatomic components and haemodynamic features of this type of vascular malformation. METHODS: In two cases, intraoperative microvascular Doppler was used to assist in the surgical obliteration of dural arteriovenous fistula of the spinal cord. The fistulas were identified prior to the dura opening, and for this only minimally invasive surgery was required. Direct recordings of the arterialised draining vein and the nidus of the fistula demonstrated a pathological spectrum caused by the arterial supply and the disturbed venous outflow in which a high-resistance flow pattern and low diastolic flow resembling an arterial-like flow velocity were observed. FINDINGS: The fistulas were obliterated by interruption of the draining vein, and Doppler measurements provided information on flow velocity changes in the medullary veins from an arterial to a venous pattern. The absence of any residual flow in the draining vein confirmed successful haemodynamic treatment. INTERPRETATION: Intraoperative microvascular Doppler recording is valuable assistance in surgical closure of spinal arteriovenous fistula.

Intraoperative microvascular Doppler monitoring of blood flow within a spinal dural arteriovenous fistula: a precious surgical tool. Case report.

The authors describe a case of spinal arteriovenous fistula (AVF) treated by a microvascular Doppler-assisted surgical interruption of the arterialized vein. Microvascular Doppler monitoring represents a valid, widely available, noninvasive tool that enables identification, through flow spectrum analysis, of components of this type of vascular malformation. In this case because the location of the fistula was identified prior to opening the dura only minimally invasive surgery was required. Direct recordings of the arterialized draining vein and the nidus of the fistula demonstrated a pathological spectrum caused by the arterial supply and the disturbed venous outflow in which a high-resistance flow pattern and low diastolic flow resembling an arterial-like flow velocity were observed. The fistula was obliterated by interruption of the draining vein, and Doppler measurements provided information on flow velocity changes in the medullary veins from an arterial to a venous pattern. The absence of any residual flow in the AVF confirmed successful hemodynamic treatment. Intraoperative microvascular Doppler recording during surgical closure of spinal AVF is a widely available and reliable monitoring modality that helps to produce excellent clinical results.

Pallidotomy improves quality of life in selected parkinsonian patients: an Italian report.

Pallidotomy has recently been reconfirmed as effective for otherwise intractable symptoms of Parkinson's disease. Nonetheless almost every aspect of its performance requires choices which are not fully established and may vary between centers. These include: 1) patient selection; 2) choice of imaging modality, 3) choice of anatomic landmarks for targeting the lesion, 4) choice of method for physiologic confirmation of location, 5) choice of lesion size and shape. We present two cases of pallidotomy procedures in Parkinsonian patients that in our knowledge are the first reported in Italy. Our experience and a careful review of the literature led to the following choices: 1) selection of Parkinsonian patients with dominant L-Dopa induced dyskinesia, akinetic and rigidity symptoms, 2) use of CT due to the distortion effects of MRI, 3) use of standard (Laitinen) coordinates combined with an image fusion method using MRI, 4) use of stimulation to gauge distance to internal capsule and optic tract, 5) production of vertical lesion covering internal segment of pallidum. At a 1-year follow-up the results include a 45% drop in UPDRS (Unified Parkinson's Disease Rating Scale) motor score and almost complete resolution of contralateral dopa induced dyskinesias in both patients.

Do spinal meningiomas penetrate the pial layer? Correlation between magnetic resonance imaging and microsurgical findings and intracranial tumor interfaces.

OBJECTIVE: To study the relationships between spinal dura-arachnoid and tumor-cord interfaces in spinal meningiomas and to investigate whether a disruption of the pial layer and penetration of the tumor in the spinal cord occurs. METHODS: Fifteen patients with histologically proven meningiomas underwent magnetic resonance imaging (MRI) preoperatively. All patients underwent microsurgery. The histological characteristics of the tumors were compared with MRI and microsurgical findings. RESULTS: At surgery, the peritumoral hypointense rim revealed by MRI in 10 of 15 patients corresponded to a well-defined cerebrospinal fluid-containing space confined between the outer arachnoidal layer and the inner leptomeningeal layer. In those patients in whom the hypointense peritumoral rim was absent, the inner layer was either difficult to identify or clearly absent, and the blood vessels were extremely adherent to the tumor, requiring a more cautious dissection. Penetration of the tumors through disruption of the pial surface was not documented. CONCLUSION: Previous anatomic and electron microscopy studies demonstrated, in human spinal meninges, the presence of an intermediate layer attached to the inner aspect of the arachnoid, extending laterally over the dorsal surface of the spinal cord and arborizing over the nerve roots and blood vessels. The intermediate layer is not present in human cerebral leptomeninges. The presence/absence of this layer might explain the hypointense rim detected by MRI and might also explain why no penetration and no peritumoral edema is observed in spinal meningiomas as compared with intracranial meningiomas.

Use of middle cerebral velocity and blood pressure for the analysis of cerebral autoregulation at various frequencies: the coherence index.

A common component in many protocols for the evaluation of cerebral autoregulation is the comparison of transcranial Doppler ultrasound (TCD) velocities with blood pressure recordings, in which correlations between these two signals correspond to impaired autoregulation. With long data sets and complicated paradigms, however, visual inspection alone cannot adequately distinguish random coincidence from consistent correlation in a statistically valid fashion. We suggest and illustrate the use of the coherence index for this purpose. To illustrate this technique, long-term recordings of TCD velocity and blood pressure were obtained from 6 normal subjects and using 23 data segments from 8 patients following subarachnoid hemorrhage. Each signal was first normalized to its mean, and coherence calculated by dividing the data into overlapping subintervals and computing an average. Coherence was specifically examined over time periods of 30 sec. Coherence calculations identified correlations between signals for which interpretation by visual inspection was unclear, and obvious correlations could be quantified. In 4 of the 6 normal subjects, the coherence was less than 0.60 but slightly greater than 0. Five of the 8 patients showed segments with coherence of greater than 0.60. The coherence index provides a quantitative tool for the evaluation of comparisons between two complex signals. As this task becomes more common in the evaluation of cerebral autoregulation, algorithms of this sort will become increasingly necessary.

Cervical neuroma presenting as a subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: The association of subarachnoid hemorrhage (SAH) with spinal lesions is well known, but hemorrhage from a cervical schwannoma is exceedingly rare. The histopathology and the mechanism of bleeding are discussed. CLINICAL PRESENTATION: We report a healthy 37-year-old man presenting with SAH after intense physical stress caused by bleeding of a cervical neuroma. INTERVENTION: A C6-T1 laminectomy disclosed an ovoid lesion, 4 cm in diameter; extremely dilated veins originated from the tumor. Removal of the spinal lesion resulted in immediate decongestion of the related venous network. The histopathological examination confirmed that the lesion was a telangiectatic schwannoma. The mechanism of bleeding of the intraforaminal cervical schwannoma is discussed. CONCLUSION: Telangiectatic neuromas may be a cause of occult SAH. The importance of magnetic resonance imaging of the cervical spine is emphasized to explain SAH with negative findings on four-vessel angiography in patients whose SAH may have a surgically correctable cause distant from the intracranial compartment.

Intraoperative monitoring of cerebral blood flow during ventricular shunting in hydrocephalic pediatric patients.

Several studies have demonstrated lowered cerebral blood flow (CBF) in patients with hydrocephalus and symptoms of raised intracranial pressure. Ventricular shunting in such cases permits a sudden increase in CBF. The pathophysiology of functional brain deficit secondary to hydrocephalus is little understood. Improvement of the patient's clinical status after drainage of CSF suggests that cerebral dysfunction is not necessarily due to permanent brain damage. In fact, it improves rapidly after ventricular taps. In view of this it would be helpful to monitor cerebral perfusion. The transcranial Doppler (TCD) ultrasonography technique allows real-time monitoring of the intracranial circulation and makes it possible to evaluate the physiopathological correlation between ventricular dilatation and CBF. Continuous monitoring of the middle cerebral artery (MCA) by TCD was performed in three hydrocephalic children (2 months, 14 months, and 8 years old) during a ventricular-peritoneal shunt operative procedure. A TC-2000S device provided by an IMP-F fixed probe was utilized. In all patients, when the lateral ventricle was shunted and the CSF could flow away, a clear and sudden increase of flow velocity above 30% was detected. The pulsatility index (PI) was also pathologically increased in all patients. A gradual normalization of this index was revealed after the shunting procedure. Our experience has to be considered preliminary, but nonetheless, it suggests a clear correlation between hydrocephalic disease and concomitant CBF alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Peritumoral edema in meningiomas: microsurgical observations of different brain tumor interfaces related to computed tomography.

Although generally benign tumors, meningiomas may be associated with extensive peritumoral brain edema as seen on computed tomographic scans. Fifty-two patients with intracranial meningiomas were studied, and the hypodense areas on computed tomographic scans were related to the intraoperative microsurgical findings and to the sizes of the tumors. We have identified three kinds of tumor-brain interfaces characterized by different difficulties in microsurgical dissection: smooth type, transitional type, and invasive type. These different microsurgical interfaces seem to correlate very precisely with computed tomographic images of halo-like and finger-like hypodense areas, allowing prediction of the microsurgical effort to be made in the surgery of meningiomas. The size of the tumor seems to be important in our subjects in determining the amount of edema produced. Indeed, a positive correlation (P < 0.001) was found between the sizes of the tumors and the extent of peritumoral hypodensity. A positive correlation (P < 0.002) also has been found between grade of edema and cortical penetration. Cerebral cortex disruption was systematically observed by us in invasive-type meningiomas and in 3 of 21 cases (14.3%) in transitional-type meningiomas. No penetration was observed in smooth-type meningiomas.

Endothelin: an endothelium-derived vasoactive peptide and its possible role in the pathogenesis of cerebral vasospasm.

The contractile response to endothelin has been examined in cerebral arteries from rats subjected to a prior subarachnoid haemorrhage (SAH) and compared with saline injected controls. Endothelin elicited strong concentration-dependent contraction of rat basilar artery segments. The response was slow in onset and long lasting. The endothelin-induced contraction was much stronger in the SAH compared to control animals. Our findings suggest a role of the peptide in the pathophysiology of cerebral vasospasm.