Spinal Cord Interface Restores Bladder Control in Preclinical Study

Loss of bladder sensation and control, known as neurogenic bladder, is a pervasive consequence of spinal cord injury. Patients face incontinence, recurrent urinary infections, and life‑threatening urosepsis, while care often relies on rigid catheterization schedules that ignore actual bladder filling. This gap undermines autonomy and increases complications. To help address this challenge, researchers have developed a spinal cord–targeted neuromodulation strategy aimed at restoring both the urge to void and coordinated emptying.

A team at the University of Southern California (USC; Los Angeles, CA, USA) is advancing a “spinal cord machine interface” focused on the dorsolateral funiculus, a sensory fiber tract that conveys bladder fullness. The approach underpins the Bladder‑Linked Stimulation System (BLISS), which targets spinal pathways rather than cerebral circuits to re‑engage natural reflexes. Custom microelectrode arrays from Ecate LLC, a USC‑affiliated startup, provide fine‑scale access to candidate spinal cord regions.

In rat models, the investigators mapped neural activity during controlled bladder filling and identified a roughly 100‑by‑100‑micrometer hotspot within the dorsolateral funiculus whose rhythmic bursting scaled from about 30 hertz at initial filling to nearly 100 hertz just before voiding. Adjacent electrodes as close as 65 micrometers remained silent, indicating a spatially discrete signal. The anatomical consistency across animals suggests a reproducible target for intervention.

In a separate group, patterned intraspinal stimulation at the mapped coordinates elicited coordinated voiding in 91.7% of trials, reaching 100% when the bladder was pre‑filled to the volume that normally triggers native signaling. Electromyography from leg muscles stayed quiescent, indicating bladder‑specific effects rather than a generalized motor reflex. The work, published in 2026 in IEEE Transactions on Neural Systems and Rehabilitation Engineering, involved the Keck School of Medicine of USC and the USC Viterbi School of Engineering, including the Alfred E. Mann Department of Biomedical Engineering.

The envisioned BLISS platform would couple the sensory interface with a bladder volume sensor and a motor stimulator to create a closed loop that restores the feeling of fullness and synchronized detrusor–sphincter control. The team has moved to larger animal models and anticipates, with adequate funding, that initial human recordings could begin within approximately 18 months during spinal cord tumor surgeries, which add minimal risk and often involve patients with bladder dysfunction.

“It’s socially a huge problem. And medically, all of my brain‑computer interface patients have a severe episode of urosepsis every year. I’ve known patients who died from this,” said Charles Liu, professor of neurological surgery and neurology at the Keck School of Medicine of USC and director of the USC Neurorestoration Center.

"The spinal cord is not just a cable. Bladder control is sparsely distributed in the brain. But here, we can directly target one region and trigger the sense of bladder filling," said Shan Zhong, postdoctoral researcher at the USC Viterbi School of Engineering. "The best thing about this is that it can actually make people feel that there is a need for voiding, instead of depending on alarm clocks."

Related Links
USC Viterbi School of Engineering
Keck School of Medicine of USC