Spinal Cord Stimulation in Pregnancy: A Literature Review

Objective: Currently, the use of spinal cord stimulation (SCS) therapy is not recommended in pregnancy because the effects of SCS on the pregnancy and developing fetus are unknown. However, many SCS recipients are women of childbearing age who may later become pregnant. The purpose of the present report is to review and summarize the existing literature on the use of SCS therapy during the prenatal period. Methods: We first present the case of a 38‐year‐old woman from our center who became pregnant after receiving an SCS implantation. We then provide a synopsis of previous reports that were identified in a literature search. We highlight the key findings from these cases as they relate to the course of pregnancy, fetal development, labor and delivery management, fertility, and technical complications. Results: In our literature review, we identified 12 cases of pregnancy in 8 women. To these we add the present case. Conclusions: Women of childbearing age who are candidates for SCS implantation should be tested for pregnancy prior to implantation surgery. They also should be informed about the limited state of our scientific knowledge regarding the impact of this technology on reproductive health. For patients already implanted with SCS, decisions about ongoing use in the event of pregnancy should be made on an individual basis after a careful consideration of potential risks and benefits.     

Burst Spinal Cord Stimulation in Pregnancy: First Clinical Experiences

ObjectivesSpinal cord stimulation (SCS) is a treatment for chronic neuropathic pain. It is based on the delivery of electric impulses to the spinal cord, traditionally in a regular square-wave pattern (“tonic” stimulation) and, more recently, in a rhythmic train-of-five “BurstDR” pattern. The safety of active SCS therapy in pregnancy is not established, and recommendations are based on limited casuistic evidence. We present in this study clinical data on a case series of six women treated with burst SCS during pregnancy. In addition, we present the ultrasonographic flow measurements of fetal and uteroplacental blood flow in a pregnant patient.Materials and MethodsPatients were included if they had been implanted with a full SCS system at Aarhus University Hospital, Denmark, between 2006 and 2020 and received active burst SCS stimulation during a pregnancy. Telephone interviews were conducted, including details on SCS therapy, medication, pregnancy course and outcome, and health status of the offspring. In one patient, the uteroplacental and fetal blood flow was assessed in gestational week 29 by Doppler flow measurements performed during both ON and OFF phases of the SCS system.ResultsSix patients were included with a total of 11 pregnancies. Three pregnancies ended in miscarriages, all in the same patient who had preexisting significant risk factors for miscarriage. Eight resulted in a live-born child with normal birth weight for gestational age; seven were born at term, and one was born late preterm, in gestational week 36. Ultrasonographic Doppler flow, measured in one patient, was normal and did not reveal any immediate changes between burst SCS ON and OFF. Seven children were reported healthy with normal neurodevelopment and one physically healthy but with developmental delays.ConclusionsThe data presented in this study add to the accumulating evidence of the safety of SCS in pregnancy.     

Spinal Cord Stimulation for Post‐Herniorrhaphy Pain

Objective. Post‐herniorrhaphy pain syndrome can be difficult to treat. The exact mechanism of pain is not always apparent. Multiple therapeutic modalities have been suggested for the treatment of this syndrome. Method. This includes both conservative (medical management), surgical (scar revision, excision of neuroma), and/or interventional approaches (local blocks to the entrapped nerves or sympathetic ganglion). Results. Two cases of intractable post–herniorrhaphy pain syndrome which failed to respond to conservative therapy are reviewed. Both cases had a successful trial therapy with spinal cord stimulation for their pain. Both then had permanent implantable systems inserted with favorable outcomes. Conclusion. Post‐herniorrhaphy pain can have the same features of both nociceptive and neuropathic pain syndromes. In cases which have failed conservative therapy we believe that a trial of spinal cord stimulation is warranted as in other cases of neuropathic pain syndromes.     

Spinal Cord Stimulation and the Pregnant Patient‐Specific Considerations for Management: A Case Series and Review of the Literature

Objectives: The use of spinal cord stimulation (SCS) is a form of neuromodulation used to treat chronic pain in those patients who are refractory to conventional medical management. Not uncommonly, SCS can dramatically improve a patient's quality of life, and those who are in the childbearing years may go on to become pregnant. The purpose of this case series is to describe: 1) implantation considerations in women of childbearing age; 2) use of rechargeable systems; 3) the obstetric and anesthetic concerns in patients with spinal cord stimulators; 4) risks of using SCS in the peripartum period. Materials and Methods: Two female patients with complex regional pain syndrome I (CRPS I) who were well managed with SCS became pregnant. In both patients, the leads were placed through the T12/L1 interspace and the generator was placed in the buttock region. In the first patient, the device was deactivated prior to conception and maintained off for the duration of the pregnancy. The second patient became pregnant on two separate occasions, with active SCS for a portion of the first trimester. During her second pregnancy, the patient elected to use of SCS at 30 weeks' gestation. Results: The developing fetuses with intrauterine exposure to SCS were followed out for a minimum of two years and are developmentally normal. The physical presence of the device did not complicate obstetric or anesthetic care. Rechargeable SCS systems were not adversely affected when turned off for the duration of the pregnancy. Conclusion: Implantation of SCS devices in women of childbearing years should take into account the future needs of both obstetric and anesthetic care by avoiding the abdomen and lower lumbar spine whenever possible. There was no appreciable decline of battery capacity in present day constant current rechargeable generators when deactivated for the duration of pregnancy.     

Cervical Spinal Cord Stimulation for Pain: A Report on 41 Patients

The objectives of this study were to assess the effectiveness of cervical spinal cord stimulation in the management of intractable pain syndromes affecting the upper limb and face and to assess the reliability of a specific electrode system in this mobile environment. Forty‐one patients, aged 26–76 years (median 48) with neuropathic or ischemic pain underwent the cervical epidural implantation of identical dual two‐contact paddle (four contacts per system) laminectomy electrodes. Follow‐up (from 5 months to 11 years, 3 months; median 4 years, 7 months) was by multiple consultations carried out by the surgeon and/or in a nurse‐led specialist clinic. Overall, 68% obtained sustained pain relief, rated as significant in 51% of the total. Facial pain did not respond. Ischemic syndromes responded well. Lead fracture rate was 15% of the original (11% of the total including replacements) and only 7% (5%) became dislodged.We conclude that the electrode system described provides reliable and sustained cervical cord stimulation. The outcomes are comparable with thoracic cord stimulation for neuropathic and ischemic syndromes.     

Continuous Versus Intermittent Spinal Cord Stimulation: An Analysis of Factors Influencing Clinical Efficacy

Objectives: Spinal cord stimulation (SCS) has, for decades, been shown to be successful in a variety of chronic neuropathic pain syndromes. However, there is a paucity of reports in the literature comparing different stimulation patterns. The impact of different stimulation patterns upon outcome remains to be determined, as well as how the latter is influenced by the duration of the post‐SCS pain‐free interval. Materials and Methods: Data from 61 patients (of 71 eligible patients) were collected by means of a telephone interview. These data included the pattern of stimulation (intermittent or continuous), the intensity of stimulation with regard to threshold, the mean, maximal, and minimal pain strength on a numerical rating scale with and without stimulation, the average duration and number of daily stimulation intervals, the average duration of the pain‐relieving effect after switching off the impulse generator, the pain medication intake, the extent of paresthesia coverage, unpleasant side effects, and patient satisfaction. Results: The average improvement in pain score following SCS was 3.10 (50.61%). Twenty‐four patients (39.3%) performed continuous stimulation, and 37 patients (60.7%) performed intermittent stimulation. Patients who performed continuous stimulation had significantly shorter pain‐free intervals following the cessation of stimulation. These patients also showed a tendency toward higher pain scores with and without stimulation, which was not statistically significant. There were no significant differences in pain scores, duration of pain relief, and usage of the stimulation system between patients with different diagnoses and lead locations. Conclusion: Our data showed an equal effectiveness of SCS in the intermittent and in the continuous stimulation mode. The duration of the post‐SCS pain‐free interval may be predictive for the choice of the most effective individual stimulation pattern and deserves further investigation.     

Sjögren Syndrome and Spinal Cord Stimulation: A Case Report

Sjögren syndrome is a chronic autoimmune disease. This disease mainly involves salivary and lacrimal glands, although it may also involve the musculoskeletal, respiratory, gastrointestinal, renal, hepato‐biliary, hematological, neurological, vascular, or both systems. Small vessel disease may appear in up to 30% of the cases. We present a case report of a 62‐year‐old female diagnosed with Sjögren syndrome. Systemic associated manifestations of her disease included interstiticial vessel vasculitis with a necrotic, sharp, and painful ulceration in her left heel. Because of refractory pain to common analgesic medical therapies (paracetamol, metamizol, and tramadol), she was referred to our pain unit for evaluation and treatment prior to limb amputation. In our pain unit, a percutaneous posterior spinal cord stimulator (SCS) was placed. SCS clinically reduced her pain by 90% and helped to improve her quality of life and significantly reduced her intake of analgesics. We conclude spinal cord stimulation may be a good alternative to conservative therapies in patients with vasculitis of Sjögren syndrome.     

Spinal Cord Stimulation for the Management of Complex Regional Pain Syndromes

The following account discusses the possible mechanisms by which spinal cord stimulation can control symptoms of Complex Regional Pain Syndromes. A review of the literature with a methodology for its incorporation in a treatment algorithm and associated technical aspects is suggested.     

Physiology of Spinal Cord Stimulation: Review and Update

Spinal cord stimulation (SCS) was an outgrowth of the well-known gate control theory presented by Melzack and Wall in 1965. Although the method has been used to treat chronic severe pain for more than three decades, very little was known about the physiological and biochemical mechanisms behind the beneficial effects until recently. We now know that SCS activates several different mechanisms to treat different types of pain such as neuropathic and ischemic. In general, these mechanisms seem most dependent on activation of only a few segments of the spinal cord. However, both animal studies and human observations have indicated that supraspinal circuits may contribute as well. In the treatment of neuropathic pain, intermittent SCS may give several hours of pain relief after cessation of the stimulation. This protracted effect indicates long-lasting modulation of neural activity involving changes in the local transmitter systems in the dorsal horns. In ischemic pain, animal experiments demonstrate that inhibition of afferent activity in the spinothalamic tracts, long-term suppression of sympathetic activity, and antidromic effects on peripheral reflex circuits may take part in the pain alleviation. Moderate SCS intensities seem to evoke sympathetic inhibition, but higher stimulation intensities may induce antidromically mediated release of vasoactive substances, eg, the calcitonin gene-related peptide (CGRP), resulting in peripheral vasodilation. The anti-ischemic effect of SCS in angina pectoris due to intermittent coronary ischemia probably occurs because application of SCS appears to result in a redistribution of cardiac blood supply, as well as a decrease in tissue oxygen demand. Recent studies indicate that SCS modulates the activity of cardiac intrinsic neurons thereby restricting the arrythmogenic consequences of intermittent local coronary ischemia. The present state of knowledge is briefly reviewed and recent research directions outlined.     

Spinal Cord Stimulation for Pain Management in Ankylosing Spondylitis: A Case Report

Introduction. The classic presentation of ankylosing spondylitis not only impairs spinal mobility but also imposes functional limitations, and fatigue is common. Methods. We report here the outcomes of spinal cord stimulation (SCS) in the case of a 47‐year‐old man with low back and hip/thigh pain due to ankylosing spondylitis, with failed responses to conservative therapies aimed at treating this pain. Results. Spinal cord stimulation induced axial low back and bilateral hip paresthesia resulting in complete subjective pain relief, cessation of analgesic medications, reduced fatigue, and improved sleep patterns. SCS also resulted in improved socioeconomic outcomes with a return to work. Conclusions. With further research in patients with broader presentations of the disease, SCS may prove efficacious in suppressing intractable pain symptoms due to ankylosing spondylitis, thus improving quality of life measures.     

Review of Spinal Cord Stimulation in Peripheral Arterial Disease

Ever since its initial development in the late 1960s, spinal cord stimulation (SCS) has been used to treat a number of painful conditions. European practice, in contrast to that in North America, has used peripheral arterial disease (PAD) as a primary indication for SCS. First employed in patients with PAD in 1976, SCS was shown by Cook et al. to heal chronic leg ulcers. Numerous subsequent retrospective studies of SCS in PAD show improvements in multiple outcomes such as exercise tolerance, limb salvage, and pain. Previous retrospective studies are likely flawed with respect to author bias, inadequate sample size, and possible placebo effects. Further, they have not identified clinical criteria for selecting SCS therapy. Recent randomized prospective studies have questioned some of the conclusions from these preceding retrospective data. In addition to the questions related to outcomes, theories regarding exact mechanisms by which SCS improves circulatory parameters remain unclear. A thorough Medline literature review on the subject of SCS in peripheral vascular disease was thus undertaken to attempt to clarify questions regarding which patients are best suited for SCS therapy, pinpoint possible methodologic flaws in previous studies, and to review the background, outcomes, mechanisms of action, complications, and alternatives for SCS in patients with PAD.