Sacral Neuromodulation (SNM) is an effective treatment for lower urinary tract dysfunction, but achieving optimal lead placement often requires lengthy procedures and reliance on fluoroscopy. We introduce the 3D Sacral Neuromodulation–Surgical Planning (3DSNM-SP) technique, a novel, patient-specific 3D approach to enhance precision and reproducibility in SNM.

The process of creating a patient-specific 3D anatomical model from radiological DICOM images to be used in sacral neuromodulation (SNM) surgical planning is primarily performed using image processing and segmentation software. 

The process is as follows:
*Image Loading: Radiological DICOM images are opened as a working file within Mimics Innovation Suite 26 software.
*Tissue Thresholding: A tissue threshold value in Hounsfield Units (HU) is assigned to separate anatomical structures. This step allows for the masking of the targeted tissue, such as bone.
*Region Growing: The anatomical region of interest is customized using the "Region Growing" command, and a precise mask is created.
*Anatomical Segmentation: The necessary anatomical segmentation operations are performed on the resulting mask using the "Edit Mask" and "Split Mask" commands. This allows for the precise boundaries of the targeted bone structure to be defined.
*Solid Model Conversion: The resulting masks are converted into solid 3D models using the "Calculate Part" command.
*Surgical Planning and Measurements: These 3D solid parts are imported into 3-Matic software. 

Linear and angular measurements are taken to guide surgical planning. These measurements include:
*Needle entry angle 
*The distance from the Trajectory Entry Point to the S3 Foramen
*The distance from the Trajectory Entry Point to the Coccyx 
*The distance from the S3 Foramen to the Coccyx 
*The distance from the S3 Foramen to the Midline 
*The distance from the Trajectory Entry Point to the Midline 
*The width and depth measurements of the S3 Foramen

Once these steps are completed, a patient-specific, high-precision 3D anatomical roadmap is created for the surgical procedure.

In this educational video, we demonstrate the step-by-step application of this technique. A total of 21 patients (mean age 42.6 years) with voiding dysfunctions underwent SNM's first stage. Preoperative planning involved sacrum-specific CT-based 3D modeling (using Mimics®) to measure individualized anatomical parameters, including the coccyx–S3 distance (mean 69.8 mm), insertion angle (mean 61.0°), and entry point location.
During surgery, pre-calculated landmarks were transferred directly onto the skin. Needle insertion was performed without anteroposterior fluoroscopy, guided only by these 3D measurements. Correct S3 localization was quickly verified by the bellows response and toe reflex.
The results demonstrate high efficiency: the mean operative time was 45 minutes (32–55), with a mean of just 1.3 needle attempts (1–2) and an average of 0.9 minutes to localize the S3 foramen. No intraoperative complications or additional fluoroscopy were required beyond minimal lateral confirmation.

The 3DSNM-SP technique provides a clear, individualized anatomical roadmap, significantly reducing operative time and minimizing radiation exposure. This method represents a pivotal evolution, establishing that patient-specific 3D planning can dramatically improve the safety, accuracy, and reproducibility of SNM procedures.

Innovative training modality for sacral neuromodulation (SNM): Patient-specific computerized tomography (CT) reconstructed 3D-printed training system: ICS School of Modern Technology novel training modality. Aydogan TB, Patel M, Digesu A, Mourad S, Castro Diaz D, Ezer M, Huri E. Neurourol Urodyn. 2023 Jan;42(1):297-302. doi: 10.1002/nau.25083. Epub 2022 Nov 2. PMID: 36321797