Assessment of language lateralization in epilepsy patients using the super-selective Wada test.

BACKGROUND: The classical Wada test (cWada), performed by injecting a short-acting anesthetic through the intracarotid route, helps determine language dominance. In the cWada, adverse effects are observed in 10-30% of trials, hindering accurate assessments. In this study, we assessed the effectiveness of the super-selective Wada test (ssWada), a more selective approach for anesthetic infusion into the middle cerebral artery (MCA). METHODS: We retrospectively examined the data of 17 patients with epilepsy who underwent ssWada via anesthetic injection into one M1 segment of the MCA and at least one contralateral trial. RESULTS: The ssWada identified 12 patients with left language dominance, 3 with right language dominance, and 2 with bilateral language distribution. Nine trials on the language dominant side resulted in global aphasia for patients with left- or right language dominance. Of the 13 trials conducted on the non-dominant language side, 12 revealed intact language function and one resulted in confusion. Among these, the outcomes of global aphasia or no language impairment were confirmed in the contralateral trials. Among the 22 trials of unilateral M1 injections in patients with unilateral language dominance, 21 (95.5%) showed either global aphasia or no language impairment, indicating language dominance. CONCLUSIONS: The ssWada yields clear results, with a high rate of over 90% in determining the language dominant hemisphere with few side effects.

Methodological assessment of the reduction of dissemination risk and quantification of debris dispersion during dissection with a surgical aspirator.

OBJECTIVE: We developed an actuator-driven pulsed water jet (ADPJ) device to achieve maximal lesion dissection with minimal risk of normal structural damage. Despite the unique dissection characteristics, there is a risk of dissemination of tissue dispersion; however, there is no established method to quantify the dispersion. Hence, this study aimed to assess the factors associated with dispersion and propose a simple experimental method using spectrophotometry to evaluate the degree of dispersion in a wet field. RESULTS: Methylene blue-stained brain phantom gelatin was immersed in a chamber with distilled water solution and dissected with an ADPJ. The dispersed gelatin solution was stirred and warmed to dissolve. The absorbance of the solution was measured spectrophotometrically. First, a reference standard curve was constructed to confirm the relationship between the absorbance and the amount of the dispersed gelatin. A clear proportional correlation was observed, which indicated that absorbance measurements can help evaluate the amount of dispersion. Using this method, we revealed that a high dissection force, insufficient suction, and inappropriate long distance between the nozzle tip and the target were associated with increased dispersion. This method might constitute a versatile and reliable approach to evaluate dispersion and aid in the development of surgical devices.

[Efficacy of halo-vest fixation in the assessment and prediction of the effectiveness of permanent fixation in a patient with basilar invagination with ambiguous vertebral instability].

Basilar invagination is a developmental anomaly of the craniovertebral junction in which the odontoid abnormally prolapses into the foramen magnum. It is also associated with Chiari malformation, syringomyelia, and hydrocephalus. Patients require surgical treatment to prevent progression of neurological symptoms, but assessment of anterior or posterior decompression can be difficult owing to bone instability and ambiguous compression of neural structures. Here, we describe a case of basilar invagination in a young adult. He presented with neurological symptoms, including syringomyelia, 3 months after a traffic trauma that might have led to instability of the bony structures. Since it was unclear whether the instability of the bony structures contributed to the clinical deterioration, the patient was first treated using halo-vest fixation. Significant improvements were observed in both neurological symptoms and magnetic resonance images. These results justified the invasive fixation and the patient was treated further with an occipito-cervical fusion ; good results were achieved in this case. Owing to the invasiveness of the procedure, occipito-cervical fixation should only be adopted following strict indication criteria. Halo-vest fixation was effective in treating the instability of the bony structures and as a trial treatment for permanent fixation.