Spinal cord stimulation uses pulsed electrical energy near the spinal cord to manage pain.[1] Initially, this technique applied pulsed energy in the intrathecal space.[2] Presently, neuromodulation involves the implantation of leads in the epidural space. A similar principle utilizes the central nervous system and the peripheral nervous system stimulation in deep/cortical brain stimulation and peripheral nerve stimulation, respectively. Neurostimulation modalities arose as a response to treating the gate control theory of pain by Melzack and Wall. In summary, they posed that pain impulses provoked in the periphery, which are carried by C fibers and A-delta fibers, could be interrupted by stimulating larger A-beta fibers. This interruption is facilitated by the common nerve synapse location in the substantia gelatinosa of the dorsal horn. In other words, stimulation of the touch and vibration nerves “closes the gate” on ascending pain impulses that carry noxious pain stimuli cephalad.[2] Multiple pain systems are responsible for the sensation of pain; these systems are composed of integrative neuronal sets (conduct excitatory or inhibitory signals on the nociceptors).[3] The interrelation that exists among these three systems at all times is responsible for the perceived sensation of pain and the responses associated with it. First, nociceptors receive signals of noxious temperature, chemical, or mechanical stimuli (peripheral neurons). They send this information to second-order neurons located in the spinal cord, mainly in the dorsal horn (central pathways), which are then transmitted via projection neurons to the brainstem (integrative neurons).
Nociceptive fibers (peripheral pain receptors)
For the spinal cord stimulator leads to be introduced into the spinal cord, the epidural space needs to be accessed using an epidural needle. Therefore, there is relevant anatomy that merits consideration during this procedure.
Spinal cord stimulation has proven its efficacy in refractory and difficult-to-treat pain syndromes. However, to enhance outcomes, it must also be cost-effective. In 2005, North and colleagues studied the cost-utility between SCS therapy and reoperation. The mean per-patient cost was $105928 for reoperation versus $48457 for SCS. Ultimately SCS was more effective and less expensive than reoperation in post-laminectomy syndrome patients.[21] Another randomized controlled trial by North et al. determined that if SCS fails, reoperation is unlikely to succeed and should be discouraged.[29]
Stimulation has shown a cost-benefit when compared to non-stimulation in the treatment of chronic back pain. Kumar et al. in 2002 followed 104 patients with failed back surgery syndrome, where 60 patients received implants. The control group (54 patients, non-stim) and the experimental group (60 patients, stim) were followed for five years. The average annual cost for the control group was $38000 versus $29000 for the stim group. The higher healthcare costs in the non-stimulator group were attributed to more medications, more follow-up visits, emergency center visits or hospitalizations, imaging (X-rays and MRIs), and rehab centers/physical therapy.[30]
The interprofessional team is necessary for the best outcomes. Pain physicians and nurses, interventional radiologists, neurosurgeons, surgical nurses, radiology technicians, and pharmacists all participate in care. Nursing will provide followup and coordinate activities among other professionals and specialists with the surgeon. Pharmacists will oversee the patient's medication regimen, assist in preventing opioid misuse or dependence, and consult with the team regarding any potential drug interactions. The interprofessional approach will lead to improved patient outcomes. [Level 5]