Spinal Root and Spinal Cord Stimulation for Restoration of Function in Lower-Limb Amputees
Condition: Traumatic Amputation of Lower Extremity; Phantom Limb Pain
MeSH terms: Phantom Limb; Amputation, Traumatic
Study type: Interventional

Summary: 
      The goals of this study are to provide sensory information to amputees and reduce phantom
      limb pain via electrical stimulation of the lumbar spinal cord and spinal nerves. The spinal
      nerves convey sensory information from peripheral nerves to higher order centers in the
      brain. These structures still remain intact after amputation and electrical stimulation of
      the dorsal spinal nerves in individuals with intact limbs and amputees has been demonstrated
      to generate paresthetic sensory percepts referred to portions of the distal limb. Further,
      there is recent evidence that careful modulation of stimulation parameters can convert
      paresthetic sensations to more naturalistic ones when stimulating peripheral nerves in
      amputees. However, it is currently unclear whether it is possible to achieve this same
      conversion when stimulating the spinal nerves, and if those naturalistic sensations can have
      positive effects on phantom limb pain. As a first step towards those goals, in this study,
      the investigators will quantify the sensations generated by electrical stimulation of the
      spinal nerves, study the relationship between stimulation parameters and the quality of those
      sensations, measure changes in control of a prosthesis with sensory stimulation, and quantify
      the effects of that stimulation on the perception of the phantom limb and any associated
      pain.
    

Detailed description: 
      During the study, FDA-cleared spinal cord stimulator leads will be placed in the lumbar
      epidural space of lower limb amputees and steered laterally towards the dorsal spinal roots
      under fluoroscopic guidance. This approach is essentially identical to the FDA-cleared
      procedure in which these devices are placed in the lumbar epidural space for treatment of
      intractable low back and leg pain. In that procedure, it is common clinical practice to place
      2-3 leads temporarily in the epidural space through a percutaneous approach and perform a
      multiday trial to determine if the patient experiences any pain reduction from spinal cord
      stimulation. Following the trial, the percutaneous leads are typically removed by gently
      pulling on them, and the patient is referred to a neurosurgeon for permanent surgical
      implantation.

      Similarly, in this study, the device will be tunneled percutaneously through the skin and
      secured in place with tape or suture. Using the stylet included with the spinal cord
      stimulator leads, the devices will be steered laterally under fluoroscopic guidance to target
      the dorsal spinal nerves. During lab experiments, the leads will be connected to an external
      stimulator. In this study, the devices will remain in the epidural space for less than 30
      days and will be removed by gently pulling on the external portion. Throughout the study, the
      investigators will perform a series of psychophysical evaluations to characterize the sensory
      percepts evoked by epidural stimulation, along with functional evaluations of the effects of
      stimulation on the ability to control a prosthetic limb. In addition, the investigators will
      perform surveys to characterize changes in phantom limb sensation and pain that occur during
      stimulation.
    

Intervention name(s): Spinal cord stimulator
Intervention type(s): Device
Intervention description(s): Spinal cord stimulator leads (2-3 leads) will be placed in the lumbar epidural space of lower limb amputees to determine if the patient experiences any pain reduction from spinal cord stimulation.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Phantom Limb Pain; Lower-Limb Amputation; Electrodes; Stimulation; Pain; Sensation