Cognitive Fusion Six-Needle Localization for Stage I Sacral Neuromodulation: A Noninferiority Study

Conventional C-arm fluoroscopy for sacral neuromodulation (SNM) involves significant radiation exposure and prolonged procedural duration. We evaluated a cognitive fusion six-needle localization technique that reduces intraoperative fluoroscopy and uses only preoperative computed tomography (CT) for guidance; it is designed to streamline surgical steps in patients with normal sacral anatomy.

This retrospective cohort study enrolled patients undergoing stage I SNM using CT-assisted cognitive fusion (cognitive fusion group) at our hospital and conventional C-arm fluoroscopy (fluoroscopy group) at two other peer hospitals in 2024. All enrolled patients underwent routine preoperative sacral CT examinations. In the cognitive fusion group, initial puncture was guided by preoperative CT coordinates, including depth to the S2-S4 foramina, longitudinal distance from the coccygeal tip, and lateral displacement from the midline, and was refined based on intraoperative motor responses. Intraoperative metrics, lead placement accuracy, and clinical response rates were compared.

We included 206 patients (cognitive fusion: 107; fluoroscopy: 99) from three hospitals. Baseline demographics and symptom severity were comparable (p > 0.05). The cognitive fusion group demonstrated a significantly shorter mean operative time (34.2 ± 11.3 vs 52.1 ± 6.6 minutes, p < 0.001) than the fluoroscopy group. No significant differences were observed in the mean number of responsive contacts (2.3 vs 2.4) or the threshold response voltage (1.8V vs 1.7V, p > 0.05). In the cognitive fusion group, 92.4% of leads entered via the medial foramen border, 95.2% extended inferolaterally, and 96.2% aligned parallel to the sacral endplate. Clinical response rates were similar between the groups (80.4% vs 84.8%, p > 0.05), with no severe complications reported.

Cognitive fusion localization provides comparable accuracy and clinical efficacy to C-arm fluoroscopy while significantly reducing the operative time. This technique offers an efficient, reproducible alternative for foramen localization in the majority of SNM candidates with normal sacral development.