Epidural Spinal Cord Stimulation for Sensory Restoration and Phantom Limb Pain in Upper-Limb Amputees

Not Applicable

Completed

Conditions: Phantom Limb

Registration Number: NCT02684201

Lead Sponsor: Lee Fisher, PhD

Brief Summary: Individuals with upper-limb amputation usually have intact nerves within the residual limb, and studies have demonstrated that electrical stimulation of those nerves can produce sensations that appear to emanate from the amputated limb. In this study, investigators will examine the sensations that are produced by electrical stimulation of these nerves at the location where they exit the spinal cord. Stimulation of the spinal cord is commonly used to treat intractable back and limb pain, and the procedure includes a test phase in which electrodes are temporarily placed under the skin near the spinal cord and removed at the end of testing. Similarly, in this study, electrodes will be placed near the spinal cord in the upper back and neck, and stimulation will be applied over the course of multiple testing sessions, lasting less than 30 days. The electrodes will be removed at the last day of testing. During each testing session, electrical stimulation will be applied through the electrodes and a series of tests will be performed to determine the types of sensations produced by stimulation. In addition to producing meaningful sensations with electrical stimulation, this study will also test the effect of stimulation on phantom limb sensations and phantom limb pain.

Detailed Description: The purpose of this research study is to characterize the types of sensations that can be produced by stimulating the spinal nerves in upper-limb amputees, as well as the effects of that stimulation on phantom limb pain. The study involves a medical procedure to temporarily place one to three stimulation electrodes in the space near the spinal cord. This medical procedure will be performed under local anesthesia, and will take approximately one to two hours. Afterwards, the electrodes will be connected to an external stimulator and a series of experiments will be performed to characterize the types of sensations generated by electrical stimulation of the spinal cord and spinal nerves, as well as to measure the effect of stimulation on phantom limb sensations and phantom limb pain. Over the course of less than 30 days, there will be up to 20 of these experimental sessions. At the end of the final experimental session, the stimulation electrodes will be removed by gently pulling on them.

The investigators are inviting participants to consider participating in this research because they have an upper-limb amputation. Participants must be between the ages of 18 and 70 and at least one year post-amputation. Participants must be willing to travel to the University of Pittsburgh at least twice per week for 30 days.

Participants cannot have any serious diseases or disorders that affect your ability to participate in this study. Women who are pregnant or plan to become pregnant during the study cannot be included. The investigators will ask females of child-bearing potential to undergo a urine pregnancy test prior to any procedures (such as MRI, x-ray, fluoroscopy) that may disrupt the healthy development of an unborn child. If participants are currently taking any medications that thin their blood, participants will not be eligible for this study. Participants will have to meet other criteria to be eligible, which will be reviewed with participants upon their consent. The investigators will screen up to 15 people and expect that up to 10 individuals will complete this study.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 4

Inclusion Criteria

have an upper-limb amputation
must be between the ages of 18 and 70
be at least one year post-amputation
be willing to travel to the University of Pittsburgh at least twice per week for 29 days

Exclusion Criteria

women who are pregnant or plan to become pregnant during the study
all participants cannot have any serious diseases or disorders that affect your ability to participate in this study
must not be currently taking any medications that thin your blood

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Primary Outcome Measures

Name	Time	Method
Stimulation Thresholds to a Variety of Stimulus Parameters	30 days	Quantify the threshold (minimum charge) stimulus required to evoke sensation and neurophysiological responses during epidural spinal nerve stimulation, and monitor changes in those percepts and responses over time.
Week 1 Average Stimulus Charge for All Subjects	first 7 days of implant	The average stimulus (nC) required to evoke sensation during week 1 of implant duration.
Week 2 Average Stimulus Charge for All Subjects	During days 7-14 of implant	The average stimulus (nC) required to evoke sensation during week 2 of implant duration.
Week 3 Average Stimulus Charge for All Subjects	During days 15 to 21 of implant	The average stimulus (nC) required to evoke sensation during week 3 of implant duration.
Week 4 Average Stimulus Charge for All Subjects	During days 22-28 of implant	The average stimulus (nC) required to evoke sensation during week 4 of implant duration.

Secondary Outcome Measures

Name	Time	Method
Number of Participants Who Were Able to Discern Specific Regions of the Spinal Cord That Evoked Sensations	30 days	Evaluate the relationship between stimulation parameters and the modality and naturalness of perceived sensations.
Qualitative Self-report of Evoked Sensations	30 days	Document the subjective perception of cervical epidural spinal nerve stimulation for restoration of sensation. The investigators will ask each subject to provide subjective feedback on their perceived utility of the sensory feedback provided by the device.
Change in Pain Ratings After Study Completion	30 days	Participants were asked to complete the McGill pain questionnaire at baseline, and weekly throughout implant. We expected to see a decrease in the pain level due to electrical stimulation. A positive score indicates a decrease in level of pain (baseline - study end). Minimum score is 0. Maximum score is 80. The higher the number, the greater the pain. This outcome measure suntracts the baseline pain score from the final pain score. A positive score indicates a reduction in pain from baseline.
Success Rate During Control of Prosthetic Hand to Identify Object Size	30 days	Investigators will test the subject's ability to use a myoelectric prosthetic hand with and without sensory feedback provided by electrical stimulation of the spinal roots. Using either a virtual prosthetic limb or an instrumented prosthesis, stimulation of the spinal roots will be modulated based on signals recorded from the limb such as pressure at the finger tips or joint angles. In both the presence and absence of stimulation, subjects will be asked to perform tasks such as manipulating blocks, opening a jar, or identifying the stiffness and size of various objects.
Success Rate During Control of Prosthetic Hand to Identify Object Compliance (Soft, Medium, Hard)	30 days	Investigators tested the subject's ability to use a myoelectric prosthetic hand with and without sensory feedback provided by electrical stimulation of the spinal roots. Using either a virtual prosthetic limb or an instrumented prosthesis, stimulation of the spinal roots was modulated based on signals recorded from the limb such as pressure at the finger tips or joint angles. In both the presence and absence of stimulation, subjects were asked to perform tasks such as manipulating blocks, opening a jar, or identifying the stiffness (soft, medium, hard) and size of various objects.

Trial Locations

Locations (1): University of Pittsburgh
🇺🇸
Pittsburgh, Pennsylvania, United States
University of Pittsburgh
🇺🇸Pittsburgh, Pennsylvania, United States