Clinical trials have demonstrated that kilohertz-frequency transcutaneous spinal cord stimulation (TSCS) can be used to facilitate the recovery of sensory-motor function for patients with spinal cord injury, whereas the neural mechanism of TSCS is still undetermined so that the choice of stimulation parameters is largely dependent on the clinical experience. In this paper, a finite element model of transcutaneous spinal cord stimulation was used to calculate the electric field distribution of human spinal cord segments T ₁₂ to L ₂, whereas the activation thresholds of spinal fibers were determined by using a double-cable neuron model. Then the variation of activation thresholds was obtained by varying the carrier waveform, the interphase delay, the modulating frequency, and the modulating pulse width. Compared with the sinusoidal carrier, the usage of square carrier could significantly reduce the activation threshold of dorsal root (DR) fibers. Moreover, the variation of activation thresholds was no more than 1 V due to the varied modulating frequency and decreases with the increased modulating pulse width. For a square carrier at 10 kHz modulated by rectangular pulse with the frequency of 50 Hz and the pulse width of 1 ms, the lowest activation thresholds of DR fibers and dorsal column fibers were 27.6 V and 55.8 V, respectively. An interphase delay of 5 μs was able to reduce the activation thresholds of the DR fibers to 20.1 V. The simulation results can lay a theoretical foundation on the selection of TSCS parameters in clinical trials.
Humans ; Spinal Cord Stimulation/methods* ; Nerve Fibers/physiology* ; Finite Element Analysis ; Spinal Cord/physiology* ; Computer Simulation ; Spinal Cord Injuries/physiopathology* ; Lumbosacral Region ; Lumbar Vertebrae ; Transcutaneous Electric Nerve Stimulation/methods* ; Models, Neurological

Phantom limb pain (PLP) is a form of neuropathic pain occurring after limb amputation, and its underlying mechanisms remain unclear, posing significant challenges for clinical management. Spinal cord stimulation (SCS), a neuromodulation technique, has shown potential in relieving chronic pain, though its long-term efficacy and safety in treating PLP require further validation. This report presents a case of a 42-year-old male experiencing persistent radiating, lightning-like pain [Visual Analog Scale (VAS) score 8-9], following right upper limb amputation. Preoperative imaging revealed signal loss in the right nerve roots at C₆-T₁. A percutaneous electrode was implanted surgically to achieve full coverage of the painful region. Five days postoperatively, the VAS score dropped to 2-3, and after 1 year of follow-up, the patient continued to experience significant pain relief (VAS 1-2), with complete resolution of depressive symptoms and cessation of analgesic medication. Existing studies suggest that the long-term outcomes of SCS may fluctuate, and attention should be paid to potential complications such as infection and electrode displacement.
Humans ; Phantom Limb/therapy* ; Male ; Adult ; Spinal Cord Stimulation/methods* ; Electrodes, Implanted ; Amputation, Surgical/adverse effects*

In addition to restoration of bladder, bowel, and motor functions, alleviating the accompanying debilitating pain is equally important for improving the quality of life of patients with spinal cord injury (SCI). Currently, however, the treatment of chronic pain after SCI remains a largely unmet need. Electrical spinal cord stimulation (SCS) has been used to manage a variety of chronic pain conditions that are refractory to pharmacotherapy. Yet, its efficacy, benefit profiles, and mechanisms of action in SCI pain remain elusive, due to limited research, methodological weaknesses in previous clinical studies, and a lack of mechanistic exploration of SCS for SCI pain control. We aim to review recent studies and outline the therapeutic potential of different SCS paradigms for traumatic SCI pain. We begin with an overview of its manifestations, classification, potential underlying etiology, and current challenges for its treatment. The clinical evidence for using SCS in SCI pain is then reviewed. Finally, future perspectives of pre-clinical research and clinical study of SCS for SCI pain treatment are discussed.
Animals ; Chronic Pain ; Humans ; Pain ; etiology ; Pain Management ; methods ; Quality of Life ; Spinal Cord Injuries ; complications ; Spinal Cord Stimulation ; Treatment Outcome

Spinal cord injury (SCI), which is much in the public eye, is still a refractory disease compromising the well-being of both patients and society. In spite of there being many methods dealing with the lesion, there is still a deficiency in comprehensive strategies covering all facets of this damage. Further, we should also mention the structure called the corticospinal tract (CST) which plays a crucial role in the motor responses of organisms, and it will be the focal point of our attention. In this review, we discuss a variety of strategies targeting different dimensions following SCI and some treatments that are especially efficacious to the CST are emphasized. Over recent decades, researchers have developed many effective tactics involving five approaches: (1) tackle more extensive regions; (2) provide a regenerative microenvironment; (3) provide a glial microenvironment; (4) transplantation; and (5) other auxiliary methods, for instance, rehabilitation training and electrical stimulation. We review the basic knowledge on this disease and correlative treatments. In addition, some well-formulated perspectives and hypotheses have been delineated. We emphasize that such a multifaceted problem needs combinatorial approaches, and we analyze some discrepancies in past studies. Finally, for the future, we present numerous brand-new latent tactics which have great promise for curbing SCI.
Animals ; Astrocytes/cytology* ; Axons/physiology* ; Cell Transplantation ; Disease Models, Animal ; Electric Stimulation ; Humans ; Microglia/cytology* ; Motor Neurons/cytology* ; Nerve Regeneration ; Neuroglia/cytology* ; Neuronal Plasticity ; Neurons/cytology* ; Oligodendroglia/cytology* ; Pyramidal Tracts/pathology* ; Recovery of Function ; Regenerative Medicine/methods* ; Spinal Cord Injuries/therapy*

Spinal cord stimulation (SCS) is a promising technique for treating disorders of consciousness (DOCs). However, differences in the spatio-temporal responsiveness of the brain under varied SCS parameters remain unclear. In this pilot study, functional near-infrared spectroscopy was used to measure the hemodynamic responses of 10 DOC patients to different SCS frequencies (5 Hz, 10 Hz, 50 Hz, 70 Hz, and 100 Hz). In the prefrontal cortex, a key area in consciousness circuits, we found significantly increased hemodynamic responses at 70 Hz and 100 Hz, and significantly different hemodynamic responses between 50 Hz and 70 Hz/100 Hz. In addition, the functional connectivity between prefrontal and occipital areas was significantly improved with SCS at 70 Hz. These results demonstrated that SCS modulates the hemodynamic responses and long-range connectivity in a frequency-specific manner (with 70 Hz apparently better), perhaps by improving the cerebral blood volume and information transmission through the reticular formation-thalamus-cortex pathway.
Adolescent ; Adult ; Brain ; physiopathology ; Consciousness ; physiology ; Consciousness Disorders ; physiopathology ; therapy ; Female ; Hemodynamics ; physiology ; Humans ; Male ; Middle Aged ; Pilot Projects ; Spinal Cord ; physiopathology ; surgery ; Spinal Cord Stimulation ; methods ; Young Adult

OBJECTIVE: To find an objective and accurate examination for evaluation of spinal cord injury (SCI) in forensic clinical medicine. METHODS: The onset latency of cortex, peak latency of N1, central motor conduction time (CMCT) and wave width of the abductor pollicis brevis and the anterior tibialis were calculated by transcranial magnetic stimulation-motor evoked potential (TMS-MEP). The data of 68 patients suffered from SCI including 23 cervical levels and 45 thoracolumbar levels were collected and compared with that of 30 normal controls. RESULTS: In experimental group, when the muscle strength of the abductor pollicis brevis or the anterior tibialis decreased or disappeared, the onset latency of cortex, the peak latency of N1, and CMCT prolonged and the wave width broadened. And these indexes of grade 2 and 3 muscle strength in experimental group were higher than that in the control group (P < 0.05). CONCLUSION The TMS-MEP can determine directly and objectively the motor functional status of pyramidal tract of spinal cord in order to provide more accurate and objective evidences in forensic medicine.
Adolescent ; Adult ; Case-Control Studies ; Evoked Potentials, Motor/physiology* ; Female ; Forensic Medicine/methods* ; Humans ; Male ; Middle Aged ; Monitoring, Physiologic ; Motor Cortex/physiology* ; Muscle, Skeletal/physiology* ; Neural Conduction/physiology* ; Reaction Time/physiology* ; Spinal Cord Injuries/physiopathology* ; Transcranial Magnetic Stimulation ; Young Adult

Transcranial magnetic stimulation-motor evoked potential (TMS-MEP) test is one of the electrophysiological examination methods to evaluate the function of central nervous system. The value of the TMS-MEP has been recognized by some clinical forensic workers recently. This article reviews the principle and advantages of TMS-MEP and its application in functional evaluation of central nervous system and clinical treatment. The value of TMS-MEP in forensic medicine, especially in objective assessment of muscle strength after injury of central nervous system is also discussed.
Central Nervous System Diseases/physiopathology* ; Disability Evaluation ; Evoked Potentials, Motor/physiology* ; Forensic Medicine/methods* ; Humans ; Monitoring, Physiologic/methods* ; Motor Cortex/physiopathology* ; Muscle, Skeletal/physiopathology* ; Neural Conduction/physiology* ; Predictive Value of Tests ; Severity of Illness Index ; Spinal Cord Injuries/physiopathology* ; Transcranial Magnetic Stimulation

OBJECTIVETo evaluate the practicability and validity of transcranial magnetic motor evoked potential monitoring (TMS-MEP) during spinal surgery.

METHODSFrom February 2001 to June 2004, 37 patients undergoing spinal surgery were involved, anaesthesia was maintained with volatile anesthetics in 11 operations and etomidate in 26. Analgesia was provided with fentanyl, and non-depolarizing muscle relaxant was given intermittently. MEPs elicited with transcranial magnetic stimulations were recorded from tibialis anterior muscles, simultaneously bispectral index (BIS) and train-of-four stimulation (TOF) were used to monitor the anesthesia depth and neuromuscular blockade respectively. The variety of MEP and its effect on surgical operation at different anesthesia depth and muscular relaxation were observed, and the muscle strength of the patients before and after operation were compared.

RESULTSThe 11 cases anesthetized with isoflurane or enflurane gave no response to TMS, the other 26 cases in which anaesthesia was maintained with etomidate and fentanyl gave satisfactory TMS-MEPs, but with significantly attenuated amplitudes and prolonged latencies (P < 0.05). Intraoperative MEP showed a grossly unchanged waveform, and its amplitude and latency had little fluctuation when anaesthesia and neuromuscular blockade maintained stable. When T(1) value of TOF at 40% - 60%, a steady MEP could be acquired and the muscular contraction after TMS should not interfere the operation.Seven of 26 cases had a MEP amplitude drop up to 50% or more during the operation, the surgical team was notified to avoid further spinal injury, at last only 1 case had a worsen muscle power after operation.

CONCLUSIONSMyogenic TMS-MEP is a valid and practicable technique for intraoperative monitoring, and the etomidate + fentanyl technique is adequate for its anesthesia. BIS and TOF monitoring are helpful to maintain the steadiness of the anesthesia and MEPs, which is very important for monitoring the changes of the MEPs.

Adolescent ; Adult ; Aged ; Anesthesia ; methods ; Evoked Potentials, Motor ; physiology ; Female ; Humans ; Male ; Middle Aged ; Monitoring, Intraoperative ; methods ; Spinal Cord ; surgery ; Spine ; surgery ; Transcranial Magnetic Stimulation ; Young Adult

Excellent outcomes were achieved with spinal cord stimulation (SCS) for 7 to 10 days on 2 patients who developed postherpetic neuralgia. Both patients were within 2 to 3 months of the onset of the condition, and nerve blocks provided only temporary pain relief and drug therapies had poor efficacy. The authors believe that limited-duration SCS for subacute postherpetic neuralgia is a useful treatment approach that may prevent the pain from progressing to chronic postherpetic neuralgia.
Aged ; Electric Stimulation Therapy ; methods ; Female ; Herpes Zoster ; complications ; Humans ; Neuralgia, Postherpetic ; etiology ; physiopathology ; therapy ; Outcome Assessment (Health Care) ; Pain, Intractable ; therapy ; Spinal Cord ; physiology

Cauda Equina ; injuries ; Decompression, Surgical ; Electric Stimulation Therapy ; Emergency Medical Services ; methods ; Fracture Fixation, Internal ; Humans ; Prognosis ; Spinal Cord Injuries ; prevention & control ; therapy ; Spinal Fractures ; surgery ; Spinal Fusion