Fractional anisotropy of the optic radiations correlates with the visual field after epilepsy surgery.

PURPOSE: This study assessed whether optic radiations (OR) microstructure after temporal lobe epilepsy (TLE) surgery correlated with visual field defects (VFD). METHODS: Patients were subjected to diffusion tensor imaging (DTI) tractography of the OR and Humphrey perimetry after TLE surgery. We used Spearman's test to verify correlations between tractographic parameters and perimetry mean deviation. Tractographic variables were compared between patients with VFD or intact perimetry. Multiple logistic regression was applied between DTI and perimetry values. DTI sensitivity and specificity were assessed with a receiver operating characteristic (ROC) curve to evaluate VFD. RESULTS: Thirty-nine patients had reliable perimetry and OR tractography. There was a significant correlation between (1) fractional anisotropy (FA) and both total (rho = 0.569, p = 0.0002) and quadrant (rho = 0.453, p = 0.0037) mean deviation and (2) radial diffusivity and total mean deviation (rho = - 0.350, p = 0.0286). There was no other significant correlation. Patients with VFD showed a significantly lower FA compared with patients with normal perimetry (p = 0.0055), and a 0.01 reduction in FA was associated with a 44% increase in presenting VFD after surgery (confidence interval, CI = 1.10-1.88; p = 0.0082). Using a FA of 0.457, DTI tractography showed a specificity of 95.2% and a sensitivity of 50% to detect VFD after surgery (area under the curve = 0.7619, CI = 0.6020-0.9218). CONCLUSION: The postoperative OR microstructure correlated with visual loss after epilepsy surgery. DTI postoperative OR tractography may be helpful in evaluating VFD.

The usefulness of stereo-electroencephalography (SEEG) in the surgical management of focal epilepsy associated with "hidden" temporal pole encephalocele: a case report and literature review.

The authors report a case of 18-year-old woman with partial complex seizures compatible with temporal epilepsy by semiology. Due to medical refractoriness, she was referred to pre-surgical evaluation. Initially, MRI showed no significant structural abnormality and superficial scalp EEG demonstrated epileptiform activity in the frontotemporal areas. Due to the lack of clear MRI abnormalities and the potential involvement of dominant mesial temporal structures by seizure semiology and non-invasive data, extra-operative invasive evaluation using stereo-electroencephalography (SEEG) methodology was indicated. Invasive monitoring demonstrated seizure onset in the left temporal pole with early spread to ipsilateral amygdala. Surgical treatment resulted in resection of the temporal pole and amygdala, with preservation of the remaining mesial temporal lobe structures. Intraoperatively, it was observed that multiple dural defects in the anterior middle temporal fossa with invagination of adjacent temporal pole parenchyma are compatible with temporal encephalocele. Patient remains seizure-free since surgery (12 months follow-up period) with preservation of neuropsychological functions. Although temporal pole resection plus amygdalohippocampectomy has been described as an adequate surgical approach in temporal encephalocele cases, we demonstrated the usefulness of the SEEG methodology in minimizing the volume of temporal lobe resection without compromising seizure and neuropsychological outcomes. The optimal results in this case and the review of the literature may suggest that in medically refractory epilepsies caused by temporal pole encephaloceles, preservation of the temporal lobe mesial structures should be attempted.

Temporopolar amygdalohippocampectomy: seizure control and postoperative outcomes.

OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of a modified surgical approach for the treatment of temporal lobe epilepsy secondary to hippocampal sclerosis (HS). This modified approach, called temporopolar amygdalohippocampectomy (TP-AH), includes a transsylvian resection of the temporal pole and subsequent amygdalohippocampectomy utilizing the limen insula as an anatomical landmark. METHODS: A total of 61 patients who were diagnosed with HS and underwent TP-AH between 2013 and 2017 were enrolled. Patients performed pre- and postoperative diffusion tensor imaging and were classified according to Engel's scale for seizure control. To evaluate the functional preservation of the temporal stem white-matter fiber tracts, the authors analyzed postoperative Humphrey perimetries and pre- and postoperative neurocognitive performance (Rey Auditory Verbal Learning Test [RAVLT], Weschler Memory Scale-Revised [WMS-R], intelligence quotient [IQ], Boston Naming Test [BNT], and semantic and phonemic fluency). Demographic data and surgical complications were also recorded and described. RESULTS: After a median follow-up of 36 ± 16 months, 46 patients (75.4%) achieved Engel class I, of whom 37 (60.6%) were Engel class IA. No significant changes in either the inferior frontooccipital fasciculus and optic radiation tractography were observed postoperatively for both left- and right-side surgeries. Reliable perimetry was obtained in 40 patients (65.6%), of whom 27 (67.5%) did not present any visual field defects (VFDs) attributable to surgery, while 12 patients (30%) presented with quadrant VFD, and 1 patient (2.5%) presented with hemifield VFD. Despite a significant decline in verbal memory (p = 0.007 for WMS-R, p = 0.02 for RAVLT recognition), there were significant improvements in both IQ (p < 0.001) and visual memory (p = 0.007). Semantic and phonemic fluency, and scores on the BNT, did not change postoperatively. CONCLUSIONS: TP-AH provided seizure control similar to historical temporal lobe approaches, with a tendency to preserve the temporal stem and a satisfactory incidence of VFD. Despite a significant decline in verbal memory, there were significant improvements in both IQ and visual memory, along with preservation of executive function. This approach can be considered a natural evolution of the selective transsylvian approach.

3D-Printed Craniosynostosis Model: New Simulation Surgical Tool.

BACKGROUND: Craniosynostosis is a complex disease once it involves deep anatomic perception, and a minor mistake during surgery can be fatal. The objective of this report is to present novel 3-dimensional-printed polyamide craniosynostosis models that can improve the understanding and treatment complex pathologies. METHODS: The software InVesalius was used for segmentation of the anatomy image (from 3 patients between 6 and 9 months old). Afterward, the file was transferred to a 3-dimensional printing system and, with the use of an infrared laser, slices of powder PA 2200 were consecutively added to build a polyamide model of cranial bone. RESULTS: The 3 craniosynostosis models allowed fronto-orbital advancement, Pi procedure, and posterior distraction in the operating room environment. All aspects of the craniofacial anatomy could be shown on the models, as well as the most common craniosynostosis pathologic variations (sphenoid wing elevation, shallow orbits, jugular foramen stenosis). Another advantage of our model is its low cost, about 100 U.S. dollars or even less when several models are produced. CONCLUSIONS: Simulation is becoming an essential part of medical education for surgical training and for improving surgical safety with adequate planning. This new polyamide craniosynostosis model allowed the surgeons to have realistic tactile feedback on manipulating a child's bone and permitted execution of the main procedures for anatomic correction. It is a low-cost model. Therefore our model is an excellent option for training purposes and is potentially a new important tool to improve the quality of the management of patients with craniosynostosis.

Clinical and Imaging Evaluation of Transuncus Selective Amygdalohippocampectomy.

BACKGROUND: Various reports have described the transuncus (TU) approach as a selective route to the amygdala and hippocampus, but this approach has not yet been submitted to solid postoperative imaging analysis. The objective of this study was to evaluate the anatomy, surgical technique, postoperative imaging analysis, and outcome in a series of patients with temporal lobe epilepsy who underwent selective amigdalohippocampectomy via a TU approach. METHODS: This was a prospective study of 25 consecutive patients who underwent selective amigdalohippocampectomy through a TU approach. The temporal stem and temporal pole were evaluated through different modalities of 3-Tesla magnetic resonance imaging, including tractography of optic radiation (OR), uncinate fascicle, and inferior fronto-occipital fascicle. Visual field analysis was performed with automated perimetry. RESULTS: The mean age was 40 ± 8.21 years, and mean follow-up was 26.44 + 12.58 months. Postoperatively, 21 patients (84%) were classified as Engel I (good seizure control). Diffusion tensor imaging (DTI) data showed that 78.2% of patients had some structural damage to the temporal stem and fibers of the uncinate fascicle were identified postoperatively in only 3 patients (13.04%). The inferior fronto-occipital fascicle was identified in 18 patients (78.3%); however, subsequent DTI analysis of the remaining fibers showed them to be damaged. Integrity of the OR did not differ between these 2 groups. CONCLUSIONS: A TU approach is a feasible and efficient approach to selective amigdalohippocampectomy for surgical treatment of temporal lobe epilepsy. Postoperative DTI analysis suggests that a TU approach results in more injury to the temporal stem and its associated white matter fiber tracts than expected by previous anatomic studies; however, it was efficient in preserving OR.