Clinical Sciences/Health Conditions
Natan Bensoussan, MD, MSc candidate
Physiatrist
Université de Montréal / Hôpital du Sacré-Cœur de Montréal
Montreal, Quebec, Canada
Ariane LeBlanc Grant, BA
Medical student and MSc candidate
Université de Montréal
Montreal, Quebec, Canada
Jean-Marc Mac-Thiong, MD, PhD
Orthopedic Surgeon, Principal Investigator
Université de Montréal / Hôpital du Sacré-Cœur de Montréal / Centre Hospitalier Universitaire Sainte-Justine
Montreal, Quebec, Canada
Pascal Mputu Mputu, PhD
Clinical research coordinator
Université de Montréal / Hopital du Sacré-Coeur de Montréal
Montreal, Quebec, Canada
Andréane Richard-Denis, MD
Physiatrist
Hôpital du Sacré-Coeur de Montréal
Montreal, Quebec, Canada
Early assessment of neuro-sacral function is critical in patients with suspected cauda equina or conus medullaris syndromes (CES+) to guide timely surgical decompression. However, bedside tools such as the digital rectal examination (DRE) and trial-of-void protocols are often subjective or delayed, limiting diagnostic accuracy. This study examined whether the ElectroSacroGram (ESG), our novel bedside surface electromyography tool, can objectively assess neuro-sacral function and clarify CES+ diagnosis after a thoracolumbar (TL) stenosis/injury.
Design:
In this prospective proof-of-concept study, patients with TL injury/stenosis referred for surgical evaluation in the emergency department or outpatient clinic were included. ESG parameters (resting anal tone, maximal voluntary anal contraction (maxVAC), bulbocavernosus reflex, and sensory electrical perceptual threshold (EPT)) were recorded. CES+ diagnosis was established by consensus between spinal surgeons and physiatrists using a standardized trial of void and clinical assessment, blinded to ESG results. Diagnostic performance was evaluated using receiver operating characteristic analysis of predicted probabilities from a multivariable logistic regression model including ESG parameters.
Results:
Thirty-four patients with suspected CES+ were included (mean age 58.4 ± 17.7 years; 55.9% male). Eighteen (52.9%) had confirmed CES+, while sixteen (47.1%) did not. Most cases were non-traumatic (73.5%), primarily due to degenerative lumbar stenosis and CES (61.8%). ESG parameters differed significantly between groups, notably for deltaVAC (median 8.58 [6.38–10.8] µV vs. 10.10 [5.65–23.48] µV, p = 0.001) and EPT (7.00 [6.12–9.63] mA vs. 7.00 [5.75–7.50] mA, p < 0.001). The combined ESG model demonstrated excellent discrimination, with an area under the curve (AUC) of 0.89 (95% CI: 0.79–1.00).
Conclusion:
ESG offers a rapid, objective, and non-invasive bedside assessment of sacral function in patients with TL injuries. The model’s high discriminative accuracy supports ESG as a potential tool for early detection of CES+ and timely surgical triage. ESG could help identify patients who would benefit most from urgent decompression.
