Risk assessment methodology for trajectory planning in keyhole neurosurgery using genetic algorithms.

BACKGROUND: Preoperative assessment to find the safest trajectory in keyhole neurosurgery can reduce post operative complications. METHODS: We introduced a novel preoperative risk assessment semiautomated methodology based on the sum of N maximum risk values using a generic genetic algorithm for the safest trajectory search. RESULTS: A set of candidates trajectories were found for two surgical procedures. The trajectories search is done using a risk map considering the proximity of voxels within risk structures in multiple points and a genetic algorithm to avoid an exhaustive search. The trajectories were validated by a group of neurosurgeons. CONCLUSIONS: The trajectories obtained with the proposal method were shorter in 5% and have greater distance from the voxels within the blood vessels in 4.7%. The use of genetic algorithm (GA) speeds up the search for the safest trajectory, decreasing in 99.9% the time required for an exhaustive search.

Comparison of cerebrospinal fluid obtained by ventricular endoscopy and by lumbar puncture in patients with hydrocephalus secondary to neurocysticercosis.

BACKGROUND: Compare the differences between proteins, glucose, and morphological cellular counts from ventricular cerebrospinal fluid obtained by neuroendoscopy and lumbar puncture. METHODS: This was a retrospective, transversal study. From January 2003 until June 2006, 30 neuroendoscopies were performed on patients with hydrocephalus secondary to NCC. Samples of CSF were extracted by lumbar puncture and ventricular neuroendoscopy, and their levels of glucose, proteins, number of leukocytes, and morphological differences (PMN including eosinophiles, monocytes, and lymphocytes) were subsequently measured and studied. Traumatic CSF results were excluded. Twenty-five patients with histopathologic confirmation of the NCC diagnosis were analyzed. The average age of the patients was 42 years (SD, 19.8 years) and female-male ratio was 10:15. RESULTS: The differences in glucose values, between lumbar and ventricular CSF, were not statistically significant-lumbar, 45.28 mg/dL and ventricular, 53.92 mg/dL (P = .129). The differences in the protein values and leukocyte counts were statistically significant (P < .05) with the highest values found in lumbar CSF. The presence of monocytes was higher than that of PMNs in both fluids (P < .05). We did not find eosinophiles in any CSF. CONCLUSIONS: We did not find differences in the glucose values as described by previous studies, but our findings showed differences in the values of proteins, PMN leukocytes, and monocytes. The presence of more monocytes could be explained by their incremented activation by the parasite antigen and chronicity of the disease. Translational trials with uniform criteria are needed to determinate the immune process in the several presentations of the disease in humans.

A Novel Approach of Navigation-Assisted Flexible Neuroendoscopy.

BACKGROUND AND IMPORTANCE: Neuronavigation-assisted endoscopy is commonly used for skull base and intraventricular surgery. Flexible neuroendoscopy offers certain advantages over rigid endoscopy; however, a major disadvantage of the flexible endoscope has been easy disorientation in the flexed position. Neuronavigation-assisted flexible neuroendoscopy was not available until now. This is the first report of the use of navigation-assisted flexible neuroendoscopy in a patient with hydrocephalus. CLINICAL PRESENTATION: A 10-mo-old girl presented with irritability and vomiting to the emergency department and was found to have severe hydrocephalus. The patient underwent successful endoscopic third ventriculostomy and exploration of the ventricles (lateral, third, cerebral aqueduct, fourth) and basal cisterns with the flexible neuroendoscopy assisted with electromagnetic neuronavigation. CONCLUSION: As demonstrated by this initial experience, neuronavigation-assisted flexible neuroendoscopy is a feasible and safe tool, endoscopic procedures with the flexible endoscope may be possible in a safer manner. We report the first use of neuronavigation-assisted flexible neuroendoscopy to perform an ETV and exploration of the entire ventricular system. Further evaluation will be necessary to define and expand its applications in neurosurgery.

Endoscopic scoring system for extraparenchymal neurocysticercosis.

OBJECTIVE: To propose a scoring system using endoscopy for assessment of the inflammatory alterations caused by neurocysticercosis (NCC) inside the ventricular cavities and the basal subarachnoid space. METHODS: Video recordings of the endoscopic procedures in patients with hydrocephalus secondary to NCC were assessed in a two-phase study. In the first phase (n = 10), the assigned score of each patient was correlated with the cerebrospinal fluid values obtained by lumbar and ventricular puncture. Reproducibility was determined using an intraclass correlation coefficient. In the second phase (n = 30), the prognostic value of the score was tested by comparing it with the patient's Karnofsky performance score (KPS) 3 months after endoscopy. RESULTS: The score included four main components: ependymal findings, number of involved sites, abnormalities in the subarachnoid space, and other alterations. These values were summed to produce a total score, which correlated strongly with both protein and cell counts from ventricular cerebrospinal fluid. The intraclass correlation coefficient of the global score was 0.85. In the second phase, the scores were divided into mild, moderate, and severe categories (6, 15, and 9 patients). The initial KPS was similar between the groups (P = 0.56); however, when measured 3 months later, there were significant differences (P = 0.02). The logistic regression analysis of patients with a score in the severe range (odds ratio = 0.09; 95% confidence interval, 0.06-0.64) showed a reduced chance for achieving a good outcome (KPS ≥90) after 3 months. CONCLUSIONS: Our scoring system enables endoscopic classification of the damage caused by NCC in the ventricular and basal subarachnoid space. The score has a biologic basis and a good internal reproducibility. The score seems to be useful for determining the short-term prognosis, and patients with high scores require additional therapeutic measures to improve their outcomes.

Endoscopic management of hydrocephalus due to neurocysticercosis.

OBJECTIVE: Hydrocephalus due to neurocysticercosis usually shows poor prognosis and shunt failure is a common complication. Neuroendoscopy has been suggested as treatment, but the indications remain unclear. METHODS: A cohort of patients with clinical/radiological diagnosis of hydrocephalus due to NCC, treated between January 2002 and September 2006, were the subjects of the study. We excluded patients with tumors or those in whom diagnosis was not confirmed (histology/positive ELISA in CSF). Neuroendoscopy was offered as the first line of treatment. Shunt failure rate and Karnofsky index at 12 months were assessed. RESULTS: Eighty-six patients (47 male) with a median age of 38 (9-79) were included in the study. Of them, 36.1% had a shunt before endoscopy and 97.7% had a Karnofsky index <80. We did not find the parasite in 18.6%, extraction was achieved in 79%, and in 87.2% an endoscopic third ventriculostomy (ETV) was performed. The median follow-up time was 43 months (1-72). Shunt failure was seen in 6.6% of patients with ETV in comparison to 27.2% in those without ETV. A hazard ratio of 0.22 (95% CI, 0.05-0.93) for shunt failure after ETV was calculated. At 12 months, 20.9% had a Karnofsky index <80. CONCLUSION: Early extraction of parasite plus ETV might allow improving outcome and reducing shunt failure. Limitation of inflammatory stimulation by parasite antigens and improvement of CSF dynamics could be an explanation for these findings.