Wellingson Silva Paiva

Aplication of the stereolithography technique in complex spine surgery

Many techniques have been proposed for surgical training as a learning process for young surgeons or for the simulation of complex procedures. Stereolithograpfy, a rapid prototyping technique, has been presented recently as an option for these purposes. We describe the case of a 12 years old boy, diagnosed with Ewings sarcoma in the cervical spine. After a surgical simulation accomplished in the prototype, built by stereolithography, the patient was submitted to a C4 corpectomy and to a C4 and C3 laminectomy with anterior and posterior fixation, a non intercurrence procedure. This technique is an innovative and complementary tool in diagnosis and therapy. As a result, it is easier for the surgeon to understand the complexity of the case and plan the approach before any surgical procedure.

Cerebral hemodynamics: concepts of clinical importance

Cerebral hemodynamics and metabolism are frequently impaired in a wide range of neurological diseases, including traumatic brain injury and stroke, with several pathophysiological mechanisms of injury. The resultant uncoupling of cerebral blood flow and metabolism can trigger secondary brain lesions, particularly in early phases, consequently worsening the patients outcome. Cerebral blood flow regulation is influenced by blood gas content, blood viscosity, body temperature, cardiac output, altitude, cerebrovascular autoregulation, and neurovascular coupling, mediated by chemical agents such as nitric oxide (NO), carbon monoxide (CO), eicosanoid products, oxygen-derived free radicals, endothelins, K+, H+, and adenosine. A better understanding of these factors is valuable for the management of neurocritical care patients. The assessment of both cerebral hemodynamics and metabolism in the acute phase of neurocritical care conditions may contribute to a more effective planning of therapeutic strategies for reducing secondary brain lesions. In this review, the authors have discussed concepts of cerebral hemodynamics, considering aspects of clinical importance.

Cortical mapping with navigated transcranial magnetic stimulation in low-grade glioma surgery.

Transcranial magnetic stimulation (TMS) is a promising method for both investigation and therapeutic treatment of psychiatric and neurologic disorders and, more recently, for brain mapping. This study describes the application of navigated TMS for motor cortex mapping in patients with a brain tumor located close to the precentral gyrus. Materials and methods In this prospective study, six patients with low-grade gliomas in or near the precentral gyrus underwent TMS, and their motor responses were correlated to locations in the cortex around the lesion, generating a functional map overlaid on three-dimensional magnetic resonance imaging (MRI) scans of the brain. To determine the accuracy of this new method, we compared TMS mapping with the gold standard mapping with direct cortical electrical stimulation in surgery. The same navigation system and TMS-generated map were used during the surgical resection procedure. Results The motor cortex could be clearly mapped using both methods. The locations corresponding to the hand and forearm, found during intraoperative mapping, showed a close spatial relationship to the homotopic areas identified by TMS mapping. The mean distance between TMS and direct cortical electrical stimulation (DES) was 4.16 ± 1.02 mm (range: 2.56–5.27 mm). Conclusion Preoperative mapping of the motor cortex with navigated TMS prior to brain tumor resection is a useful presurgical planning tool with good accuracy.

Mecanismos de lesão cerebral no traumatismo cranioencefálico

Traumatic brain injury is the main cause of death and disability in children and adults in Western Countries. The definitive brain injury is a consequence of pathophysiological mechanisms that begin at the moment of an accident and may extend for days or weeks. Traumatic brain injury may be classified as diffuse or focal. These two mechanisms are commonly associated in a patient, however one is generally predominant. Therefore knowledge of the pathophysiological mechanisms of brain injury in head trauma is important to establish the therapeutic, clinical and surgical measures. In this paper the authors present a critical review of the literature on the pathophysiological principles of traumatic brain injury.

Clinical utility of brain stimulation modalities following traumatic brain injury: current evidence.

Traumatic brain injury (TBI) remains the main cause of disability and a major public health problem worldwide. This review focuses on the neurophysiology of TBI, and the rationale and current state of evidence of clinical application of brain stimulation to promote TBI recovery, particularly on consciousness, cognitive function, motor impairments, and psychiatric conditions. We discuss the mechanisms of different brain stimulation techniques including major noninvasive and invasive stimulations. Thus far, most noninvasive brain stimulation interventions have been nontargeted and focused on the chronic phase of recovery after TBI. In the acute stages, there is limited available evidence of the efficacy and safety of brain stimulation to improve functional outcomes. Comparing the studies across different techniques, transcranial direct current stimulation is the intervention that currently has the higher number of properly designed clinical trials, though total number is still small. We recognize the need for larger studies with target neuroplasticity modulation to fully explore the benefits of brain stimulation to effect TBI recovery during different stages of recovery.

Idiopathic distal lenticulostriate artery aneurysm in a child

The authors describe a rare case of idiopathic distal lenticulostriate artery (LSA) aneurysm in a 5-year-old boy who presented in the emergency department with a sudden onset of headache. Admission computed tomography scans revealed an intracerebral hemorrhage in the left caudate nucleus with intraventricular extension. Angiographic studies demonstrated a left medial LSA aneurysm. The patient underwent a left parasagittal frontal craniotomy, the lateral ventricle was accessed via the anterior transcallosal approach, and the aneurysm was removed after sectioning of the parent vessel. The child left the hospital after 5 days; at that time he was asymptomatic and without motor impairment. The optimum treatment of aneurysms involving small perforating arteries is controversial and depends mainly on the causative factors. The pathogenesis and treatment of these unusual aneurysms are discussed.

Intracranial vascular lesions associated with small epidural hematomas.

OBJECTIVE We studied the angiographic findings in patients with small epidural hematomas and cranial fractures crossing over the trajectory of the middle meningeal artery and its branches. Additionally, the occurrence of traumatic vascular lesions and their clinical relevance and treatment are discussed. METHODS A consecutive analysis was performed for 24 patients who harbored small epidural hematomas in middle meningeal artery topography associated with cranial fractures. Computed tomographic scans and plain x-ray studies were used to diagnose linear cranial fractures. Patients with large epidural hematomas or associated traumatic lesions were excluded from the study. Selective ipsilateral external carotid angiograms were obtained, and an endovascular procedure was performed if any vascular injury was evidenced. RESULTS In all patients with cranial fractures crossing over the middle meningeal artery and its branches, some kind of vascular lesion was seen. Two types of findings were noted: active extravasation of the contrast medium (71%) and pseudoaneurysms (29%). Early filling of diploic vessels was found in 8.3% of fractures concomitantly with active extravasation. Embolization was performed in all patients. No additional enlargement of the epidural hematoma was observed, and the postoperative period was uneventful. CONCLUSION This study shows that pseudoaneurysms and active extravasation of contrast are common findings in this subset of patients. Although the natural history of these lesions is still poorly understood, additional investigation with ipsilateral external carotid angiography may be recommended, considering the potentially catastrophic consequences of late rupture.

Failed back surgery pain syndrome: therapeutic approach descriptive study in 56 patients

OBJECTIVE The authors show the clinical evaluation and follow-up results in 56 patients diagnosed with a failed back surgery pain syndrome. METHODS Descriptive and prospective study conducted over a one-year period. In this study, 56 patients with a failed back surgery pain syndrome were assessed in our facility. The age ranged from 28 to 76 years (mean, 48.8 ± 13.9 years). The pain was assessed through a Visual Analog Scale (VAS). RESULTS Postoperative pain was more severe (mean VAS score 8.3) than preoperative pain (7.2). Myofascial pain syndromes (MPS) were diagnosed in 85.7% of patients; neuropathic abnormalities associated or not with MPS were found in 73.3%. Drug therapy associated with physical medicine treatment provided > 50% pain improvement in 57.2% of cases; trigger point injection in 60.1%, and epidural infusion of morphine with lidocaína in 69.3% of refractory cases. CONCLUSION In patients with a post-laminectomy syndrome, postoperative pain was more severe than preoperative pain from a herniated disk. A miofascial component was found in most patients.

Effects of hyperbaric oxygenation therapy on symptomatic pneumocephalus

Background Pneumocephalus (PNC) is defined as a pathological collection of gas within the cranial cavity. The authors studied the effects of hyperbaric oxygenation (HBO2) therapy on a group of patients with PNC, comparing them with a control group to determine the relative impact on pneumocephalus volume, clinical symptoms, and duration of hospitalization. Methods Twenty-four patients with PNC treated at our hospital were consecutively studied. These patients were divided into a treated group (n=13) and a control group (n=11). Thirteen patients (treated group) were treated with HBO2 therapy sessions in a monoplace hyperbaric chamber at 2.5 atmospheres with 100% oxygen concentration. The control group was treated with normobaric oxygenation. Results Clinical improvement was seen in all patients. In the treated group, a decrease of the gas bubble was observed on the computerized tomography scan after each session of HBO2. The treated group also experienced a lower rate of meningitis compared with the control group. The length of hospital stay was significantly higher in the control group compared with the treated group. Conclusions HBO2 therapy in selective cases may lead to clinical and radiological improvement in patients with PNC.

Comprehensive cognitive and cerebral hemodynamic evaluation after cranioplasty

Decompressive craniectomy is an established procedure to lower intracranial pressure and can save patients’ lives. However, this procedure is associated with delayed cognitive decline and cerebral hemodynamics complications. Studies show the benefits of cranioplasty beyond cosmetic aspects, including brain protection, and functional and cerebrovascular aspects, but a detailed description of the concrete changes following this procedure are lacking. In this paper, the authors report a patient with trephine syndrome who underwent cranioplasty; comprehensive cognitive and cerebral hemodynamic evaluations were performed prior to and following the cranioplasty. The discussion was based on a critical literature review.