MRI-guided stereotactic system for delivery of intraspinal microstimulation

Spine (Phila Pa 1976), 2016 · DOI: 10.1097/BRS.0000000000001397 · Published: July 1, 2016

Simple Explanation

This study introduces a new MRI-guided system for delivering intraspinal microstimulation (ISMS) to treat spinal cord injuries. ISMS shows promise in restoring motor function, but accurate electrode placement is crucial. The system uses MRI to visualize and target specific areas in the spinal cord, accounting for individual anatomical differences. This aims to improve the precision of electrode placement compared to existing methods. The system's accuracy was tested using a phantom and in live pigs, confirming its ability to precisely deliver electrodes to targeted areas within the spinal cord. The system was also tested for its ability to evoke hind limb function.

Study Duration

Not specified

Participants

Two in vivo pig experiments

Evidence Level

Laboratory/animal based proof of principle study

Key Findings

1
The root mean squared (RMS) error between actual frame coordinates and software-coordinates, both acquired using the test phantom, was 1.09 ± 0.20 mm.
2
Post-operative CT in the anesthetized pig confirmed spatially accurate electrode placement relative to preoperative MRI.
3
MRI-guided delivery of a microwire electrode followed by intraspinal microstimulation evoked repeatable electromyography responses in the biceps femoris muscle.

Research Summary

This study presents a novel MRI-guided stereotactic system for accurate intraspinal electrode targeting and delivery. The system's accuracy was validated using a phantom and in vivo pig model, demonstrating its ability to precisely place electrodes in the spinal cord. The system's adaptability was demonstrated by implanting a microelectrode array and evoking hind limb responses through intraspinal microstimulation.

Practical Implications

Improved Accuracy in ISMS Electrode Placement

The MRI-guided system offers improved accuracy in electrode placement compared to traditional methods, potentially leading to more effective ISMS therapy.

Reduced Tissue Damage

By improving targeting accuracy, the system may reduce the number of electrode penetrations required, minimizing tissue damage and the risk of complications.

Versatile Platform for Spinal Cord Therapies

The stereotactic system can be adapted to deliver various spinal cord therapies, including ISMS electrodes, enzymes, biomaterials, regenerative cells, and growth factors.

Study Limitations

1
The accuracy reported relies on a fixed target and it is important to recognize the spinal cord is a moving target in vivo due to its physiologic pulsations with the cardiorespiratory cycle.
2
Successful targeting of functional responses based on anatomical locations within the spinal cord remains to be seen.
3
Implantation of rigid microwire electrodes inherently results in displacement of neural tissue and disruption of the blood brain barrier, thereby leading to inflammation and gliosis that can reduce stimulation efficacy.

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury