The Potential Applications of Augmented Reality in Fetoscopic Surgery for Antenatal Treatment of Myelomeningocele.

OBJECTIVE: To develop a preoperative planning method using augmented reality (AR) of a specific surgical procedure: fetoscopy for myelomeningocele repair. METHODS: Imaging data were acquired of a pregnant woman at 27 weeks of gestation whose fetus was diagnosed with myelomeningocele. The patient was identified as a candidate for fetoscopic repair of the spine defect, and an AR application for mobile device simulation was developed. The virtual customized model was created by analysis of the presurgical magnetic resonance imaging. A real-time AR interface was developed by using an application that enhanced the anatomical aspects of both mother and fetus. RESULTS: A virtual model for planning fetoscopy repair for myelomeningocele was developed. Preoperative and postoperative procedures were successfully carried out, emphasizing the beneficial role of the AR application. The use of the AR model allowed the multidisciplinary team to engage in discussion to determine the appropriate surgical approach. It also allowed a clearer explanation of the procedure to the parents enabling a better understanding of the parents regarding specifics characteristics of their baby's spine defect. CONCLUSIONS: This new preoperative platform using a virtual model represents an important tool to improve patient's comprehension, multidisciplinary discussion, and surgical planning. In addition, it can be used worldwide as a teaching tool in the fetal surgery field.

Neurocircuitry of Deep Brain Stimulation for Obsessive-Compulsive Disorder as Revealed by Tractography: A Systematic Review.

Objective: Deep brain stimulation (DBS) was proposed in 1999 to treat refractory obsessive-compulsive disorder (OCD). Despite the accumulated experience over more than two decades, 30-40% of patients fail to respond to this procedure. One potential reason to explain why some patients do not improve in the postoperative period is that DBS might not have engaged structural therapeutic networks that are crucial to a favorable outcome in non-responders. This article reviews magnetic resonance imaging diffusion studies (DTI-MRI), analyzing neural networks likely modulated by DBS in OCD patients and their corresponding clinical outcome. Methods: We used a systematic review process to search for studies published from 2005 to 2020 in six electronic databases. Search terms included obsessive-compulsive disorder, deep brain stimulation, diffusion-weighted imaging, diffusion tensor imaging, diffusion tractography, tractography, connectome, diffusion analyses, and white matter. No restriction was made concerning the surgical target, DTI-MRI technique and the method of data processing. Results: Eight studies published in the last 15 years were fully assessed. Most of them used 3 Tesla DTI-MRI, and different methods of data acquisition and processing. There was no consensus on potential structures and networks underlying DBS effects. Most studies stimulated the ventral anterior limb of the internal capsule (ALIC)/nucleus accumbens. However, the contribution of different white matter pathways that run through the ALIC for the effects of DBS remains elusive. Moreover, the improvement of cognitive and affective symptoms in OCD patients probably relies on electric modulation of distinct networks. Conclusion: Though, tractography is a valuable tool to understand neural circuits, the effects of modulating different fiber tracts in OCD are still unclear. Future advances on image acquisition and data processing and a larger number of studies are still required for the understanding of the role of tractography-based targeting and to clarify the importance of different tracts for the mechanisms of DBS.

Preoperative Planning Modalities for Meningoencephalocele: New Proof of Concept.

OBJECTIVE: Late surgical correction of meningoencephalocele is a rare scenario that remains challenging for surgeons. Three-dimensional models can mimic the correct anatomical relationships, and technological systems have brought advances to medicine. This study aims to present a novel preoperative planning modality that combines augmented reality with a hybrid model for complex malformation associated with late correction. METHODS: The present report describes a case of frontoethmoidal encephalocele of a 10-year-old girl. Two different methods for planning the approach were developed: 1) a hybrid hands-on model and 2) augmented reality, using a cell phone app and headset display. The customized hybrid model was created based on patient's imaging. The augmented reality app was developed with a real-time interface. RESULTS: The hybrid model recreated anatomic alterations, thereby allowing a multidisciplinary team to determine an appropriate surgical approach. All aspects of the surgical procedure were simulated. A pre- to postoperative comparison was made, which emphasized benefit of tridimensional anatomical relationships using augmented reality tool and its role in preoperative planning. CONCLUSIONS: The authors believe this new multimodality preoperative platform could be a useful method to improve multidisciplinary discussion as well as a powerful tool for teaching and planning.