Evaluation Of The Relationship Between The Position And Shape Of PBC Balloon And Meckel's Cavity By Multimodal Real-time Fusion

Objective: Using real-time image fusion technology,the position relationship between balloon and Meckel's cavity during PBC was analyzed,and statistical classification was carried out to verify the mechanism of various classification,hoping to improve the success rate of punctur.At the same time,combined with intraoperative real-time three-dimensional scanning,the relationship between balloon morphology and Meckel's cavity morphology was verified when different volumes of contrast media were injected into the balloon.Methods: The Department of Neurosurgery of Guangdong second provincial general hospital who underwent PBC surgery for trigeminal neuralgia from March 2018 to March 2019,was collected.Before operation,the trigeminal nerve was scanned by thin layer MR(0.5mm).The MR data were introduced into Medtronic neuronavigator,and the volume of Meckel's cavity was calculated and the shape was recorded by 3DSlicer software.After intubation general anesthesia,the head was tilted about 10 °,and the foramen ovale X-ray and lateral cephalic X-ray were taken with Medtronic Oarm.Under the guidance of foramen ovale X-ray,the 3cm needle was inserted outside the oral corner of the affected side to observe the area and angle at which the cannula was punctured into the foramen ovale.The balloon catheter was guided into the brain from the cannula,and the Mark at the end of the balloon catheter was not more than 5 mm behind the slope line.The relationship between the end of the balloon catheter and the foramen ovale was observed again under the X-ray of the foramen ovale.At this time,three-dimensional tomography with O-arm was performed,and the data were immediately transmitted to the neuronavigator.The tomographic images were fused with MR images,and the position relationship between PBC balloon and Meckel' s cavity was judged and classified.After confirming that the balloon catheter was located in the Meckel's cavity,the contrast medium was injected,and the O-arm threedimensional tomography was performed again to obtain the balloon volume and threedimensional shape data,combined with the statistical analysis of the volume and shape of the Meckel's cavity before operation.Results: The relationship between the position of balloon and Meckel's cavity has four forms: 1.Intracavitary type;2.Extracaval type;3.Lateral wall type of cavity;4.The medial wall of the cavity.Among them,151 cases were intraluminal type(81.72%),7 cases were extraluminal type(3.76%),25 cases were lateral wall type(13.45%),and 2 cases were intraluminal lateral wall type(1.07%).It is mainly related to the puncture of the foramen ovale and the deviation of the end of the balloon.The intraluminal type entered the needle from the inside of the foramen ovale in 125 cases(82.23%),from the center of the foramen ovale in 26 cases(17.11%),and from the outside of the foramen ovale in 1 case(0.66%).The external type entered the needle from the center of the foramen ovale in 3 cases(42.86%)and from the outside of the foramen ovale in 4 cases(57.14%).The lateral wall type entered the needle from the inside of the foramen ovale in 3 cases(12.00%),from the center of the foramen ovale in 7 cases(28.00%),from the outside of the foramen ovale in 15 cases(60.00%),and from the medial side of the foramen ovale in 2 cases(100%).Statistics from the medial,central and lateral foramen ovale into the needle,a puncture success rate of 96.15%,72.22%,5.0%(Prun0.00 < 0.05),from the inside of the foramen ovale puncture success rate is higher.The endoluminal balloon tip deviated to the medial foramen ovale in 91 cases(59.86%),the non-obvious deviation group in 61 cases(40.13%),the extraluminal balloon end in 2 cases(28.57%),and the lateral foramen ovale group in 5 cases(71.42%).The lateral wall type of balloon deviated to the medial foramen ovale in 5 cases(20.00%),no obvious deviation group in 9 cases(36.00%),lateral foramen ovale group in 11 cases(44.00%),and medial foramen ovale in 2 cases(100%).According to the statistics of the success rate when the end of the balloon was biased to the medial foramen ovale,there was no significant difference between the group with the medial end of the balloon and the group without obvious deviation,but there was a significant difference between the two groups(P < 0.05).When the end of the balloon deviated to the lateral side of the foramen ovale,the success rate decreased significantly.There are four relationships between the shape of the balloon and the shape of the Meckel's cavity during PBC,which are mainly related to their volumes.When the balloon filling volume is less than the Meckel's cavity volume,the balloon is quasi-round.When the balloon filling volume is close to the Meckel's cavity volume,the balloon shape is similar to the Meckel's cavity shape.When the balloon filling volume is about 1.7 times of the Meckel's cavity volume,the balloon is pear-shaped.When the balloon was filled in the shape of a pear,the balloon continued to expand,and the balloon developed to the posterior cranial fossa,showing a dumbbell shape.There was a significant positive correlation between the filling volume of the pyriform balloon and the volume of the Meckel's cavity.The effective compression coefficient of the pyriform balloon was 1.65 ±0.28.Conclusion: There are four kinds of position relationship between balloon and Meckel's cavity during PBC,which is related to the area where the cannula pierced into the foramen ovale and the deviation of the end of the balloon.Entering the foramen ovale from the medial area of the foramen ovale and avoiding the lateral deviation of the end of the balloon can improve the success rate of PBC puncture.There are four kinds of relationship between the shape of balloon and the shape of Meckel's cavity,which are mainly related to their volumes.When the balloon filling volume is about 1.7 times the volume of Meckel's cavity,the compression effect is the best.