Spinal Cord Stimulation in The Treatment of Phantom Limb Pain: A Case Report and Review of Literature
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.310092
Source of Support: None, Conflict of Interest: None
Keywords: Dorsal column stimulation, phantom limb syndrome, spinal cord stimulation
A 61-year-old gentleman who sustained a motor vehicle accident three years before consultation and underwent a below elbow amputation (Right) presented to our Out Patient Department (OPD) with a history pain along with a tingling sensation of the amputated arm [Figure 1]. His pain started a few days after he underwent amputation. Initially, the pain was sharp and throbbing like in nature which was intermittent but later on became almost continuous. This was accompanied by pins and needle-like sensations.
He visited several doctors and was being managed with analgesics. Initially, he was prescribed Acetaminophen, then Ketorolac. When he sought consultation at our OPD, he was already taking Nortriptyline, Pregabalin, and Lacosamide which provided only partial relief. His pain according to the visual analog score (VAS) was 8/10 (where is 0 is no pain at all and 10 means the most severe, unimaginable pain). He was diagnosed as a case of Phantom Limb Pain Syndrome and was prepared for spinal cord stimulation surgery.
Under general anesthesia, he was kept prone, laminectomy was done at C7. Chronic Dual Channel dorsal column stimulation was done using Medtronic Prime Advance SCS System. [Figure 2].
Leads were placed with the help of a C-arm. [Figure 3]a and [Figure 3]b The subcutaneous tract was made and the leads were connected with Implantable Pulse Generator (IPG) which was placed in the left lumbar region. Postoperatively, he had no complications. During his follow-ups, he underwent serial programming and his pain improved gradually. Initially, he was on monthly follow-up for the few months and then three months and now six monthly. Two years post-surgery [Figure 4], he is in much relief but complains of occasional pain (VAS4/10) that lasts for 10-15 mins, throbbing in quality too but gets relieved by using analgesics. [Table 1] shows his follow-up and relevant findings.
Phantom Limb Pain (PLP) is a chronic pain referred to an amputated limb. It is different from a stump pain which is the pain experienced in the residual portion of the amputated limb. The characteristics of pain can vary from episodic painful shocks to constant excruciating stabbing, burning, throbbing, or cramping pain. Phantom sensations have been observed in other amputated body parts as well like eyes, breast, teeth. The incidence of Phantom limb ranges from 50-80%.
Studies have shown that majority of patients (~75%) experience phantom limb pain within the initial few days. It is predominant among women, people with upper extremity amputation, presence of pre-amputation pain and residual pain in remaining limb. Several theories have been put forward to explain the phenomenon for phantom limb pain, and they are broadly categorized into peripheral and central mechanisms. The peripheral mechanism includes stump and neuroma hyperactivity. Central mechanisms include spinal cord sensitization, cortical reorganization with the remapping of the somatosensory cortex, and cortical-motor sensory dissociation.,,
Management of PLP can be divided into four sections: Pharmacological, surgical, adjuvant therapy. Pharmacological treatment consists of analgesics like opioids, anticonvulsants, tricyclic antidepressants among the others. Surgical management consists of stump revision, neurectomy, rhizotomy, sympathectomy, Spinal Cord Stimulation (SCS), cortical stimulation.
Transcutaneous electrical nerve stimulation (TENS) has been found to reduce the pain temporarily by 60%, and peripheral nerve stimulation (PNS) through the implantation of electrodes on or near the nerves, provides moderate pain relief in at least half of the patients by electrically stimulating it. The success rate of SCS in long term pain control in PLP ranges from 14-80%. The effectiveness of Dorsal Root Entry Zone lesioning on a phantom limb with intact roots was 40%. However, all patients with PLP and brachial plexus avulsion had a good response to DREZ lesioning. Similarly, thalamic (ventralis caudalis) or periventricular gray matter deep brain stimulation have a success rate of about 60%. The motor cortex was found to be effective in about 20%., Electroconvulsive therapy has also been tried in a few refractory cases.
The real mechanism by which spinal cord stimulation (SCS) alters pain in PLP is still unknown but several theories have been put forward among which gate control theory has been widely accepted. According to this theory, stimulation and activation of the Aα fibers (large myelinated fibers) within the dorsal columns will inhibit the transmission of pain information to the cortex via the Aα and C fibers (small unmyelinated fibers).,
SCS has been approved by the US Food and Drug Administration (FDA) in the management of pain in phantom pain limb, failed back surgery syndrome (FBSS), chronic peripheral neuropathy, neuropathic pain, complex regional pain syndrome (CRPS), postherpetic neuralgia, intercostal neuralgia and spinal cord injury with variable motor and sensory deficits.
SCS is offered to those adults experiencing phantom limb pain for at least 6 months, pain is of moderate to severe in intensity (VAS = 5) and significantly affecting their quality of life and daily functioning, and are not responding to trials of analgesics and/or minimally invasive treatments. The location of leads depends on the region to be anesthetized. For phantom limb pain of upper extremities, the cervical area is chosen and for the lower, the thoracolumbar region is chosen. The leads are placed after laminectomy in the levels below the desired location n slid epidurally upward. Historically, electrodes were placed sub-dural, and later, the trend then changed to epidural placement for dorsal column stimulation. These days, dorsal root ganglion has been the area of choice for stimulation as it contains the specific sensory cell bodies for better precise targeting., Initially, temporary percutaneous leads are inserted and the response is observed for a week. Once satisfactory results (=50% reduction in pain) are obtained from this trial, permanent leads are implanted. An implantable pulse generator is connected to the electrodes and placed subcutaneously in the flank or abdominal wall.
Kumar et al. in divided the patients with chronic pain into the experimental group (who received spinal cord stimulation) and the control group. He found that the average annual cost of the experimental group was $29000 vs the control group $38000. The higher cost in the control group was attributable to the frequent use of medicines, emergency, and follow-up visits, hospitalizations, investigations, and physiotherapies. [Table 2] outlines several case series of Spinal Cord Stimulation for Phantom Limb Pain with the outcomes over the years.
Complications of SCS are surgical wound infection, hardware malfunction, pain at the pulse generator site, lead migration, lead connection failure and lead breakage, neurological damage due to nerve root or cord injury. CSF leakage with subdural implantation of leads is another complication.
The result of our case is consistent with the results published in other international journals showing that spinal cord stimulation is a good treatment modality in phantom limb pain which was not relieved by pharmacological treatment alone.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]