Targeted Reinnervation for Neuromas as a Means to Improve Prosthesis Control in Major Limb Amputation
Condition: Neuroma; Pain; Prosthesis User; Prosthesis Failure
MeSH terms: Neuroma; Prosthesis Failure
Study type: Interventional

Summary: 
      Subjects are being asked to participate in this study because they have an arm or leg
      amputation and have developed pain related to a neuroma (an ongoing localized pain related to
      a cut nerve ending).

      The investigators are studying how targeted reinnervation (TR) helps to both treat neuroma
      pain and to have increased prosthetic control. This surgery connects these cut nerve endings
      to nerves going into nearby nonfunctional muscles. This surgery was developed to allow
      amputees to have better prosthesis control. By chance, neuroma pain improved significantly
      with TR. The investigators, therefore, are conducting this clinical trial. The investigators
      will ask all participants to fill out a questionnaire both before and after surgery. This
      will help us understand how a neuroma affects the quality of life of amputee will allow us to
      understand how to best improve neuroma pain and prosthesis control.

      In order to confirm the presence and location of the neuroma before surgery, a magnetic
      resonance image (MRI) will be performed. Taking these pictures requires subjects to lie still
      for a short period of time but does not involve any invasive procedures.
    

Detailed description: 
      Loss of an arm or leg is a significant injury that affects a person's job prospects, personal
      relationships, and overall quality of life. Approximately 25% of all amputees will develop
      chronic local pain in the remaining part of their amputated limb. This pain is caused by
      neuromas- disorganized nerve endings and scar tissue that form when an injured nerve tries to
      heal. Every cut nerve will develop a neuroma unless the two ends of the nerve can be
      rejoined. With limb amputation, the nerves are cut and one end is lost with the limb,
      preventing the nerve from repairing itself. Instead, the cut nerve ending forms a painful
      neuroma. Chronic pain from neuromas is a major reason that amputees cannot wear or use their
      prostheses comfortably and increases their disability.

      Even when a limb is amputated, the nerves that used to control that limb still carry messages
      from the brain. Those messages are intended to tell the muscles how or when to move the
      missing limb, but after amputation, these limb-control nerves are no longer connected to
      muscles. In 2002, researchers at Northwestern Memorial Hospital in conjunction with the
      Rehabilitation Institute of Chicago developed a new type of surgery called targeted muscle
      reinnervation (TMR). In TMR, limb-control nerves are transferred so that they can control new
      target muscles. The neuromas from the limb-control nerves are removed, then the small nerve
      that controls the target muscle is cut. The two nerves are joined together so that the
      limb-control nerve can then grow into, or reinnervate the target muscle. After TMR, when the
      person tries to move the missing limb, the target muscle contracts instead and these signals
      can be detected and used to control a prosthesis. TMR has now been done successfully almost
      100 times worldwide. Interestingly, almost all of the patients who had painful neuromas
      before TMR had no neuroma pain after surgery. This result was investigated in laboratory
      studies - both rat and rabbit amputee neuromas were "cured" with TMR. We think that giving
      the cut nerve endings somewhere to go and something to do prevents a neuroma from forming.

      We will measure the effectiveness of both surgeries using an internet-based amputee pain
      questionnaire. We expect that TMR will be more effective for neuroma pain and prosthesis
      control than the standard treatment. This will change how patients with neuroma pain are
      treated and help thousands of patients with amputations.
    

Intervention name(s): Targeted Muscle Reinnervation
Intervention type(s): Procedure
Intervention description(s): Targeted reinnervation (TR) is a surgical procedure originally designed to provide intuitive control of upper limb prostheses through transfers of residual nerves to otherwise redundant target muscle. Native motor innervation of the target muscle is cut, and the residual nerves-after excision of end-neuromas-are coapted to the motor end point of the motor nerve, close to its point of entry into the muscle. The central principle underlying the nerve transfers in TR surgery is to reestablish the function of the amputated nerve and allow intuitive, seamless prosthesis control.
Other intervention name(s): Targeted Reinnervation
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment