A novel guiding tool for lumbar puncture with the paramedian approach

Lumbar puncture is an essential procedure of the lumboperitoneal shunts that is a major treatment strategy for older patients with hydrocephalus. It can be achieved using either a median or paramedian approach. The paramedian approach shows advantages over the median approach by facilitating needle placement while avoiding narrowed interspinous spaces and kinks during catheter insertion. However, determining the correct needle placement angle remains challenging. Therefore, we aimed to establish a method for calculating the appropriate needle placement angles in the paramedian approach, and experimentally designed and produced a novel guiding tool for the lumbar puncture.

Coordinate analysis using lumbar three-dimensional computed tomography data from 53 patients (28 men, 25 women; mean age, 78.2 years) was utilized to calculate the appropriate needle placement angles. A novel guiding tool was then designed to align the puncture needle to the two optimal angles, and produced using a three-dimensional printer.

Pixel calculation of the coordinates revealed that the needle insertion angles were determined to be 30° and 33°, with no sex-related differences. Furthermore, because the target in practice has a certain volume, we analyzed the variable range of the two angles and found it to be more than 11° on average. Based on the calculated angles, we designed the novel guiding tool for lumbar puncture using the paramedian approach, defining the puncture angles as 30° and 33°.

Our method for calculating the appropriate needle placement angles using the paramedian approach is applicable for general use, allowing for the determination of proper needle placement angles prior to lumbar puncture.