Patient-Specific Ventricular Puncture Trajectory Plane and Puncture Trajectory: A Novel Method of Frontal Ventricular Puncture
Ventricular puncture is a common neurosurgical procedure, often performed freehand using body surface anatomic landmarks as targeting references. However, the failure rate of freehand lateral ventricle puncture can be as high as 43% in traumatic brain injury cases when relying solely on these landmarks. Additionally, the occurrence of hemorrhages associated with ventricular puncture can reach 16.2%. Classic puncture sites, such as the Kocher point, have been helpful in improving the success rate of ventricular puncture. Despite this, freehand puncture using classic sites remains risky due to several factors. Firstly, individual patients have varying conditions, making a universal puncture approach impractical. Secondly, the selection of the puncture approach largely depends on the surgeon’s judgment, as the puncture trajectory does not typically align with the coronal, sagittal, or axial images of regular computed tomography (CT) scans. Surgeons must rely on spatial imagination based on CT images to design the ventricular puncture trajectory (VPT), which can lead to errors. Lastly, in freehand puncture, directional deviations can easily occur without the guidance of a frame as a fixed spatial reference to the puncture path.
To address these challenges, a novel method was proposed, utilizing the connection line of the bilateral external auditory canals as the axis. A set of images containing all puncture trajectories aiming at this line can be created using CT multi-planar reconstruction (MPR) technology. Surgeons can customize the position of the VPT plane on this set of images and design the VPT accordingly. For the actual application of the selected VPT in surgery, a designed H-type guiding frame and a cell phone guiding cover were discussed.
The process begins with the use of CT MPR technology to rotationally reconstruct images using the connection line between the bilateral external auditory canals as the axis of rotation. This set of images, rotated around this axis, includes all potential puncture trajectories aiming at this line. Surgeons can then identify the individualized VPT plane and VPT on these images. This method allows for precise pre-operative evaluation and theoretically high accuracy in ventricular puncture.
For the actual application of the selected VPT in surgery, an H-type guiding frame was fabricated. This frame locates the reality VPT plane via the frame and secures the reality VPT via a guiding groove. The specific steps of designing the trajectory and obtaining parameters on the rotationally reconstructed CT images are detailed in the supplementary materials.
Additionally, a method combining multi-planar CT image reconstruction with the use of an iPhone iOS app and a cell phone guiding cover was reported. The iOS app, VirLaser Level (Version 2.6), is used to locate the puncture direction of the ventricular catheter. This app can automatically measure the vertical angle of the iPhone (the number in green on the right side of the image) and the horizontal angle (the number on the bottom right corner). With this app, the location of the iPhone can be obtained and used to guide the puncture direction of the loaded ventricular catheter.
This study suggests a novel method of ventricular puncture. Using MPR, a set of CT images was rotationally reconstructed using the connection line between the bilateral external auditory canals as the rotation axis. Individualized VPT plane and VPT can be identified on this set of images. This novel method enables ventricular puncture with adequate pre-operative evaluation and theoretical high accuracy. The core of this ventricular puncture method is to reconstruct the image plane that passes through the targets and contains the potential VPT, referring to the theoretical innovation of “implanting a curved lead to subthalamic nucleus and pedunculopontine nucleus.”
Ventricular puncture is a routine neurosurgical procedure; however, the success rate varies significantly depending on the patient’s condition. Patients with obviously dilated ventricles without deformation or location shift have a higher success rate compared to those with deformed, dilated ventricles with location shift, refined ventricles, asymmetrically dilated ventricles, no ventricle dilation, or ventricles without obvious dilation. In these challenging cases, the best puncture point, direction, and penetration depth differ between individuals. Currently, pre-operative evaluation for ventricular puncture is usually performed using the axial, coronal, and sagittal CT images, with no reconstruction performed for the trajectory plane. Most of the time, the puncture trajectory does not fall into the regular sagittal, axial, or coronal CT images. When designing the VPT, neurosurgeons need to use spatial imagination on CT images, which could lead to vector errors. The actual ventricular puncture is usually performed blindly with the surface anatomic landmarks as reference for location, and is not individualized. The success rate of the surgery is closely related to the experience and skills of the surgeon, and errors such as deviation in puncture angle and over-penetrated catheter could occur. If the puncture fails for the first time, a repeated puncture could result in brain damage caused by the catheter, or even secondary intracranial hemorrhage.
Visualizing the puncture process is an effective way to decrease the failure rate of ventricular puncture. However, methods such as real-time ultrasound, intraoperative navigation, and stereotactic frame require a special set of equipment, which significantly increases the surgical time and limits the location where the surgery can be performed. Therefore, in this research, the original pre-operative CT images were reconstructed using the MPR method. The reconstructed set of images rotated around the connection line of bilateral external auditory canals and covered all puncture trajectories aiming at this line. Individualized VPT can be precisely located on this set of images, which is helpful for the full pre-operative patient assessment. Visualization of the puncture process is thus achieved with the pre-operative selections of puncture plane and puncture trajectory, and the use of guiding frame to locate the reality VPT plane and to secure the reality VPT intra-operatively. Reconstruction of this set of images can be performed by a radiologist based on the regular pre-operative CT image, requires no additional pre-operative planning or any special set of equipment during surgery, and has less impact on pre-operative preparation time.
Finally, the theoretical localization of VPT can be designed individually on the rotationally reconstructed CT images using the line connecting the bilateral external auditory canals as the rotation axis, and applied in surgery with the help of a customized guiding frame or a cell phone guiding cover. This novel method enables ventricular puncture with adequate pre-operative evaluation and theoretical high accuracy. A further clinical study is needed to verify whether it can be considered as a useful complement to the current ventricular puncture procedures.
doi.org/10.1097/CM9.0000000000001696
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