How to Deal with "Intractable Pain" after Spinal Cord Injury? Try Transcranial Magnetic Stimulation (TMS)!

In addition to motor and sensory dysfunction and sphincter dysfunction, patients with spinal cord injury also experience persistent pain, causing them distress and suffering. Statistics show that approximately two-thirds of spinal cord injury patients experience varying degrees of post-injury pain, sometimes far exceeding the impact of functional impairment.

So, how should we deal with this kind of "pain after spinal cord injury"?

What is central pain after spinal cord injury?

Central pain is a common sequela of spinal cord injury. It refers to the persistent pain caused by damage to the central somatosensory system caused by different segments of the spinal cord.

Its incidence rate is as high as 15% to 75%. The main clinical manifestations are fixed-location burning pain and abnormal sensation to cold stimulation. In severe cases, electric shock-like or knife-like pain may occur, affecting the patient's daily work and life.

How to recover from central pain after spinal cord injury?

Currently, the prevention and treatment of central pain following spinal cord injury are still in the exploratory and clinical validation stage. Clinically, psychological intervention and drug therapy are mainly used, but the overall effects are not ideal.

Repetitive transcranial magnetic stimulation (rTMS), as a physical therapy method, has a strong stimulating effect on nerves. Currently, rTMS is used clinically as an adjunct therapy for various mental and neurological disorders.

How to treat?

The treatment used a 8-shap coil with a single pulse stimulation method. The target area was the M1 area of ​​the primary motor cortex. The stimulation frequency was 20 Hz, the intensity was 80% of the resting motor threshold, the duration was 0.75 s, the interval was 10 s, and a total of 18,000 pulses were administered once a day for 5 days a week for 8 weeks.

Repetitive transcranial magnetic stimulation (rTMS) as an adjunctive treatment can relieve central pain following spinal cord injury and improve patients' daily living abilities, demonstrating clear clinical application value.

Transcranial Magnetic Stimulator (TMS) 

 TMS is based on the principle of electromagnetic induction. A high-voltage energy storage capacitor is charged and discharged to the stimulation head in a short time. The powerful current generates a rapidly changing magnetic field around the coil, inducing an electric field and current in the peripheral nerves, thus achieving inductive stimulation. TMS can stimulate both the central and peripheral nervous systems, and is used for the detection, evaluation, and improvement of central and peripheral nerve function, as well as for the adjunctive treatment of brain nerve damage and other neurological disorders.

Application Scenarios

Psychiatry: Depression, Obsessive-Compulsive Disorder, Autism, Bipolar Disorder, Generalized Anxiety Disorder, Schizophrenia

Neurology: Epilepsy, Parkinson's Disease, Migraine, Insomnia Alzheimer's Disease

Rehabilitation Department: Stroke; Spinal Cord Injury; Dysphagia; Peripheral Nerve Injury and Motor Dysfunction

Other: Postpartum depression, Cerebral palsy in children, Childhood autism, Developmental delay in children, Addiction disorders

Clinical Application

Epilepsy: Low-frequency rTMS stimulation of the epileptic focus in the cortex is used to treat epileptic seizures.

Tinnitus: Low-frequency rTMS stimulation of the temporal or temporoparietal cortex, and high-frequency r-DLPFC stimulation are used to treat tinnitus.

Anxiety disorders: High-frequency rTMS stimulation of the r-DLPFC or low-frequency rTMS stimulation of the I-DLPFC is used to treat post-traumatic stress disorder; low-frequency rTMS stimulation of the r-DLPFC and temporoparietal region is used to treat panic attacks and generalized anxiety disorder.

Obsessive-compulsive disorder: High-frequency or low-frequency rTMS stimulation of the bilateral DLPFC is used to treat obsessive-compulsive disorder.

Schizophrenia: Low-frequency rTMS stimulation of the temporoparietal cortex treats auditory hallucinations. High-frequency rTMS stimulation of the DLPFC or bilateral DLPFC improves negative symptoms of schizophrenia.

Substance addiction: High-frequency rTMS stimulation of the I-DLPFC reduces drug cravings (psychological addiction).

Sleep disorders: Low-frequency rTMS stimulation of the bilateral DLPFC and parietal-occipital region treats sleep disorders.

Depression is the first approved clinical indication for rTMS.

rTMS is a recommended treatment option for patients with depression and those who are resistant to or intolerant of medication for depressive episodes.

rTMS can be used alone or in combination with antidepressants for the treatment of acute depressive episodes and for maintenance therapy after remission. Patients with depression who respond to rTMS treatment may receive rTMS again upon relapse.

Stroke

rTMS can promote functional recovery in stroke patients by correcting maladaptive plasticity after brain injury or enhancing adaptive plasticity during rehabilitation. Currently, rTMS treatment is most beneficial for patients with three post-stroke functional impairments: motor dysfunction, aphasia, and unilateral neglect. The rTMS treatment regimen varies depending on the specific functional impairment. Generally, it is recommended to follow rTMS with 30-60 minutes of targeted rehabilitation therapy. For the subacute phase, a treatment plan of once daily, five times a week, is recommended, with 10-20 sessions constituting one course of treatment. Depending on the patient's condition and the effectiveness of the treatment, 2-3 courses of treatment may be administered consecutively. For the chronic phase, a treatment plan of once daily, three to five times a week, is recommended.

Q&A

1. What is the contraindications?

If there are metal or electronic devices near the coil stimulation area, such as intracranial metal implants, cochlear implants, or implanted pulse generators (brain pacemakers, cardiac pacemakers), TMS may cause damage to the body or the electronic device.

Patients with a history of epilepsy or a family history of epilepsy are prohibited from using high-frequency, high-intensity TMS stimulation.

2. What is relative contraindications for TMS?

• a. Using treatment parameters exceeding safety guidelines.
• b. Having a disease that increases risk or taking medications that lower the threshold.
• c. Conditions with unknown effects, such as pregnancy. Magnetic field strength decreases rapidly with distance. For pregnant patients and operators, except when making urgent and important diagnoses, stimulation to the lower back of pregnant women should be avoided at a distance greater than 60cm.