Phantom limb pain: peripheral neuromodulatory and neuroprosthetic approaches to treatment

Abstract

Post-amputation phantom limb pain (PLP) is a widespread phenomenon that can have physical, psychological, and functional impacts on amputees who experience the condition. The varying presentations and mechanisms of PLP make it difficult to effectively provide long-term pain relief. Multiple neuromodulatory approaches to treating PLP have focused on electrical stimulation of the peripheral nervous system, with varying degrees of success. More recently, research has been done to study the effects of neuroprosthetic approaches on PLP. Neuroprosthetics combine the use of a functional prosthetic with stimulation to the peripheral nerves in the residual limb. Although many of the neuroprosthetic studies focus on improving function, several have shown preliminary evidence for the reduction of severity of PLP. In this review we provide an overview of the current understanding of the neurological mechanisms that initiate and sustain PLP, as well as the neuromodulatory and neuroprosthetic approaches under development for treatment of the condition.Muscle Nerve 59:154-167, 2019

Clinical updates on phantom limb pain

“…Due to its noninvasive nature, transcutenous electrical nerve stimulation can be a good therapeutic option for peripheral stimulation. 74,115 Even if case studies demonstrated some relief of PLP, there is a lack of high-quality evidence and mixed results for its efficiency on PLP in one systematic review. 115 External brain stimulation using transcranial direct current stimulation or repetitive transcranial magnetic stimulation have shown clinical effects during the stimulation periods in several small studies, but failed to induce longer-lasting effects-limiting their clinical applicability.…”

“…74,115 Even if case studies demonstrated some relief of PLP, there is a lack of high-quality evidence and mixed results for its efficiency on PLP in one systematic review. 115 External brain stimulation using transcranial direct current stimulation or repetitive transcranial magnetic stimulation have shown clinical effects during the stimulation periods in several small studies, but failed to induce longer-lasting effects-limiting their clinical applicability. 80,106 Invasive techniques of neuromodulation, such as peripheral nerve, spinal cord, or dorsal root ganglion stimulation, have not received widespread clinical adaption.…”

Peripheral Nerve Stimulation for Treatment of Severe Refractory Upper Extremity Post-Amputation Pain

“…With the introduction of novel, commercially available, percutaneous systems, PNS is re-emerging as a useful therapy for neuropathic pain (2,3). This modality utilizes electrodes adjacent to peripheral nerves to treat painful conditions such as peripheral neuropathic pain and complex regional pain syndrome (CRPS) (4). Recent research including a multicenter, randomized, controlled trial (RCT) has shown the effectiveness of PNS for lower extremity post-amputation pain (2,3,5).…”

Can phantom limb pain be reduced/eliminated solely by techniques applied to peripheral nerves?

“…Additional techniques effective against PLP include mirror box therapy, which involves visuomotor training of motor cortex activity, and results in restoring the body image in the M1 region of the motor cortex by restoring the original missing limb cortical representation, thus tricking the brain into thinking the missing limb is present [62][63][64][65][66], computerized visuo-motor training [63], and transcutaneous electrical nerve stimulation (TENS), which appears to interrupt pain signals before they get to the spinal cord and cortex [67][68][69]. Electrical stimulation of the spinal cord [70], and brain [71,72], have the goal of suppressing PLP by altering the activity of nerve trauma-induced altered neural circuits.…”