Neurostimulation for neurogenic bowel dysfunction

A comprehensive review of the advances in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing neuroinflammatory autoimmune astrocytopathy, with a predilection for the optic nerves and spinal cord. Most cases are characterised by aquaporin-4-antibody positivity and have a relapsing disease course, which is associated with accrual of disability. Although the prognosis in NMOSD has improved markedly over the past few years owing to advances in diagnosis and therapeutics, it remains a severe disease. In this article, we review the evolution of our understanding of NMOSD, its pathogenesis, clinical features, disease course, treatment options and associated symptoms. We also address the gaps in knowledge and areas for future research focus.

Non-pharmacological and drug treatment of autonomic dysfunction in multiple system atrophy: current status and future directions

Multiple system atrophy (MSA) is a sporadic, fatal, and rapidly progressive neurodegenerative disease of unknown etiology that is clinically characterized by autonomic failure, parkinsonism, cerebellar ataxia, and pyramidal signs in any combination. Early onset and extensive autonomic dysfunction, including cardiovascular dysfunction characterized by orthostatic hypotension (OH) and supine hypertension, urinary dysfunction characterized by overactive bladder and incomplete bladder emptying, sexual dysfunction characterized by sexual desire deficiency and erectile dysfunction, and gastrointestinal dysfunction characterized by delayed gastric emptying and constipation, are the main features of MSA. Autonomic dysfunction greatly reduces quality of life and increases mortality. Therefore, early diagnosis and intervention are urgently needed to benefit MSA patients. In this review, we aim to discuss the systematic treatment of autonomic dysfunction in MSA, and focus on the current methods, starting from non-pharmacological methods, such as patient education, psychotherapy, diet change, surgery, and neuromodulation, to various drug treatments targeting autonomic nerve and its projection fibers. In addition, we also draw attention to the interactions among various treatments, and introduce novel methods proposed in recent years, such as gene therapy, stem cell therapy, and neural prosthesis implantation. Furthermore, we elaborate on the specific targets and mechanisms of action of various drugs. We would like to call for large-scale research to determine the efficacy of these methods in the future. Finally, we point out that studies on the pathogenesis of MSA and pathophysiological mechanisms of various autonomic dysfunction would also contribute to the development of new promising treatments and concepts.

Sacral Neuromodulation Therapy for Urinary and Fecal Incontinence in Patients With Multiple Sclerosis: Report of 6 Cases and Literature Review

BACKGROUND

Urinary incontinence (UI) and fecal incontinence (FI) are challenging manifestations of multiple sclerosis (MS) that have historically been treated with limited success. Sacral neuromodulation (SNM) has provided successful resolution of UI and FI in the general population and in patients with neurologic conditions, including MS. We report on 6 patients with MS-related incontinence treated successfully with SNM and review the literature.

METHODS

Medical records were reviewed retrospectively to identify patients with MS seeking treatment for incontinence. Six patients were identified, and each is presented with follow-up assessment of the severity of UI or FI.

RESULTS

All 6 individuals with MS had severe incontinence that had been refractory to therapies that included medications and pelvic floor physical therapy. Five patients reported severe UI and 2 patients reported severe FI. Each patient was successfully treated with SNM, with large reductions of incontinence scores and improved quality of life.

CONCLUSIONS

In this case series, SNM was effective as a treatment for UI and FI among patients with MS. These findings confirm other published series that have reported the success of SNM in patients with MS with incontinence. Sacral neuromodulation should be considered as a potential treatment option for patients with MS and UI and/or FI.

Neurophysiological Effects of Electrical Stimulation on a Patient with Neurogenic Bowel Dysfunction and Cauda Equina Syndrome after Spinal Anesthesia: A Case Report

Neurogenic bowel dysfunction (NBD) is common in patients with cauda equina syndrome (CES). Previous studies have reported that electrical stimulation (ES) improves NBD but more neurophysiologic evidence is required. This case report describes a patient who experienced difficulty with defecation as a result of cauda equina syndrome (CES) that developed after a cesarean section performed 12 years ago under spinal anesthesia. The neurophysiological effects were assessed using the bulbocavernosus reflex (BCR) and electromyography (EMG). Two ES treatments, interferential current therapy and transcutaneous electrical stimulation, were used to stimulate the intestine and the external anal sphincter, respectively. The BCR results showed right-side delayed latency and no response on the left side. Needle EMG revealed abnormal spontaneous activities of the bilateral bulbocavernosus (BC) muscles. Electrodiagnostic testing revealed chronic bilateral sacral polyradiculopathy, compatible with CES. After treatment, the patient reported an improved perianal sensation, less strain and time for defecation than before, and satisfaction with her bowel condition. At the follow-up electrodiagnosis, the BCR latency was normal on the right side—needle EMG revealed reductions in the abnormal spontaneous activities of both BC muscles and re-innervation of the right BC muscle. Electrodiagnostic testing can offer insight into the neurophysiological effects of ES, which can help in understanding the mechanism of action and optimizing the therapy for patients with NBD.

Application of rectal balloon ice water stimulation for the rehabilitation of stroke patients with neurogenic bowel dysfunction

BACKGROUND

Neurogenic bowel dysfunction (NBD) is a common complication in stroke patients.

OBJECTIVE

To investigate the effect of rectal balloon ice water stimulation on the rehabilitation of patients with NBD after a cerebral stroke.

METHODS

Forty stroke patients with NBD were selected between March and August 2022 and randomly divided into a study group (n = 20) and a control group (n = 20). Based on routine rehabilitation training, rectal balloon ice water stimulation or finger rectal stimulation were performed on the study or control group, respectively. After two weeks, the changes in the NBD, self-rating depression scale (SDS) and self-rating anxiety scale (SAS) scores were compared between the two groups.

RESULTS

Before the intervention, there were no significant differences in age, sex ratio, and NBD, SDS and SAS scores between the two groups (p > 0.05). The NBD, SDS and SAS scores of both groups were significantly decreased following intervention (p < 0.05). After 2 weeks of intervention, the NBD score of the study group was significantly lower than that of the control group (5.50±1.28 vs 6.45±1.05; p = 0.014). The SDS score of the study group was lower than that of the control group, and the difference was statistically significant (32.30±2.81 vs 44.05±2.19; p = 0.014). The study group also had significantly lower SAS scores than the control group (p = 0.024). In addition, the incidence of dizziness, headaches, nausea, vomiting and abdominal pain and distension in the study group was significantly lower than in the control group (p < 0.05).

CONCLUSION

Rectal balloon ice water stimulation can significantly improve stroke patients with NBD's intestinal function and psychological status.

Transient Neurogenic Bowel Dysfunction in a Case of Cocaine-Induced Spinal Cord Infarction

A 23-year-old male presented to the hospital with altered mental status (AMS) and hypoglycemia requiring admission to the ICU. He had improvement in AMS after administration of dextrose 50% and naloxone and endorsed the use of alcohol, cocaine, and marijuana that morning. It was confirmed with a positive urine toxicology screen for cocaine and tetrahydrocannabinol (THC). During this hospital admission, his physical examination was notable for paraplegia with no motor abilities from the T6 dermatome and below. Sensation was intact throughout all dermatomes but he was found to have urinary retention. Workup included an abnormal MRI showing T2 signal spanning from T2-T8, raising a high suspicion of a probable acute ischemic spinal cord infarction. Several hours after admission, the patient began to exhibit the first signs of abnormal bowel function and experienced one episode of hematemesis, prolonging his ICU stay.

Neurogenic Bowel Dysfunction: The Impact of the Central Nervous System in Constipation and Fecal Incontinence

Spinal cord injury and neurogenic bowel dysfunction (NBD) are life-changing events for affected patients. The clinical manifestations of NBD vary depending on the level and severity of the spinal cord lesion. Managing patients with NBD can be complicated by comorbidities, such as immobility, bladder dysfunction, progressive neurologic decline, psychological factors, loss of independence, and social withdrawal, and ideally involves a multimodal, multidisciplinary approach. Evaluation and management should be individualized, depending on the residual neurologic capabilities of the patient and their predominant gastrointestinal symptoms, and commonly involves lifestyle modifications, physical therapy, laxative medications, and surgical interventions.

Neurogenic Bowel Dysfunction Changes after Osteopathic Care in Individuals with Spinal Cord Injuries: A Preliminary Randomized Controlled Trial

Background: Neurogenic bowel dysfunction (NBD) indicates bowel dysfunction due to a lack of nervous control after a central nervous system lesion. Bowel symptoms, such as difficulties with evacuation, constipation, abdominal pain and swelling, are experienced commonly among individuals with spinal cord injury (SCI). Consequentially, individuals with SCI experience a general dissatisfaction with the lower perceived quality of life (QoL). Several studies have demonstrated the positive effects of manual therapies on NBD, including Osteopathic Manipulative Treatment (OMT). This study aimed to explore OMT effects on NBD in individuals with SCI compared with Manual Placebo Treatment (MPT). Methods: The study was a double-blind randomized controlled trial composed of three phases, each one lasting 30 days (i: NBD/drugs monitoring; ii: four OMT/MPT sessions; iii: NBD/drug monitoring and follow-up evaluation). Results: the NBD scale, the QoL on worries and concerns sub-questionnaire, and the perception of abdominal swelling and constipation significantly improved after treatments compared to baseline only for individuals who underwent OMT. Conclusion: These preliminary results showed positive effects of OMT on bowel function and QoL in individuals with SCI, but further studies are needed to confirm our results.

Effects of highly selective sympathectomy on neurogenic bowel dysfunction in spinal cord injury rats

Neurogenic bowel dysfunction, including hyperreflexic and areflexic bowel, is a common complication in patients with spinal cord injury (SCI). We hypothesized that removing part of the colonic sympathetic innervation can alleviate the hyperreflexic bowel, and investigated the effect of sympathectomy on the hyperreflexic bowel of SCI rats. The peri-arterial sympathectomy of the inferior mesenteric artery (PSIMA) was performed in T8 SCI rats. The defecation habits of rats, the water content of fresh faeces, the intestinal transmission function, the defecation pressure of the distal colon, and the down-regulation of Alpha-2 adrenergic receptors in colon secondary to PSIMA were evaluated. The incidence of typical hyperreflexic bowel was 95% in SCI rats. Compared to SCI control rats, PSIMA increased the faecal water content of SCI rats by 5–13% (P < 0.05), the emptying rate of the faeces in colon within 24 h by 14–40% (P < 0.05), and the defecation pressure of colon by 10–11 mmHg (P < 0.05). These effects lasted for at least 12 weeks after PSIMA. Immunofluorescence label showed the secondary down-regulation of Alpha-2 adrenergic receptors after PSIMA occurred mainly in rats’ distal colon. PSIMA mainly removes the sympathetic innervation of the distal colon, and can relieve the hyperreflexic bowel in rats with SCI. The possible mechanism is to reduce the inhibitory effect of sympathetic activity, and enhance the regulatory effect of parasympathetic activity on the colon. This procedure could potentially be used for hyperreflexic bowel in patients with SCI.

Transcutaneous Electrical Stimulation for Neurogenic Bladder Dysfunction Following Spinal Cord Injury: Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

To assess the efficacy of transcutaneous electrical nerve stimulation (TENS) for neurogenic bladder dysfunction secondary to spinal cord injury (SCI).

MATERIALS AND METHODS

A systematic search of MEDLINE, EMBASE, Web of Science, Scopus, and Cochrane libraries up to February 2021 was performed using PRISMA methodology. All randomized controlled trials (RCTs) that studied TENS for neurogenic bladder in a SCI population were included. The primary outcomes of interest were maximum cystometric capacity (MCC) and maximum detrusor pressure (Pdet). Meta-analysis was conducted with RevMan v5.3.

RESULTS

Six RCTs involving 353 participants were included. Meta-analysis showed that TENS significantly increased MCC (standardized mean difference 1.11, 95% confidence interval [CI] 0.08-2.14, p = 0.03, I²  = 54%) in acute SCI. No benefits were seen for maximum Pdet. TENS was associated with no major adverse events.

CONCLUSIONS

TENS may be an effective, safe intervention for neurogenic bladder dysfunction following SCI. Further studies are essential to confirm these results and more work is required to determine optimal stimulation parameters and duration of the treatment.

The effect of the therapy of "combination 3 methods progression" in patients with neurogenic bowel dysfunction (constipated type): Study protocol for a randomized controlled trial

BACKGROUND

As one of the important manifestations of neurogenic bowel dysfunction, constipation is characterized by high incidence and harmful effects. It has a negative impact on both physical and psychological health of patients. And there are no effective treatment options for this type of disease clinically. Therefore, this study is designed to examine the effect of the therapy of "combination 3 methods progression" in patients with neurogenic bowel dysfunction (constipated type).

METHODS

This is a randomized, controlled, parallel-design clinical trial. A total of 60 patients with neurogenic bowel dysfunction (constipated type) will be randomly assigned to intervention group and control group. The control group will receive 4 weeks of usual rehabilitation care, the intervention group will receive 4 weeks of the therapy of "combination 3 methods progression" in addition to usual rehabilitation care. The primary outcome is the number of spontaneous bowel movement per week. Secondary outcomes are stool characteristics, degree of difficulty in defecation, level of anxiety, level of depression, and level of self-efficacy.

DISCUSSION

The interventions of this protocol have been programmed to alleviate constipation in patients with neurogenic bowel dysfunction. Findings may provide preliminary evidence for clinical efficacy of the therapy of "combination 3 methods progression."

TRIAL REGISTRATION

Chinese Clinical Trial Registry, IDF: ChiCTR2000041463. Registered on December 26, 2020.

Treatments in neurogenic bowel dysfunctions: evidence reviews and clinical recommendations in adults

INTRODUCTION

Neurogenic bowel dysfunction (NBD) is an impairment of defecation control due to any nervous system lesion negatively affecting physical health status and quality of life. We aimed at systematically assessing all available evidence on NBD treatment in adults and providing clinical management guidance and recommendations.

EVIDENCE ACQUISITION

PICOs and questions (N.=7) were identified by an expert panel. We searched for and retrieved evidence from the PUBMED and EMBASE databases, limited to the English language and the Western countries context, related to any type of setting and published from 2009 to 2019. Health effects, patient values, preferences and resource use were assessed. Of all, only RCTs, observational studies and systematic reviews on adult population (≥18 years) were analyzed. The study was conducted according to PRISMA guidelines and Cochrane recommendations. The effect size, if possible, was calculated for the interpretation of the outcomes, and evidence was assessed through the GRADE method.

EVIDENCE SYNTHESIS

Thirty-one studies were included in our qualitative synthesis. Evidence is generally scarce. Most of the outcomes are narratively described and therefore defined by imprecision. Besides, most of the included studies are affected by risk of bias. Digital stimulation was found to be effective in short term follow-up. The pharmacological treatment choice, combined or alone, needs to be balanced case by case considering clinical history, setting of use and bowel management protocol. According to only one RCT supporting evidence mainly in persons affected by spinal cord injury (SCI), trans-anal irrigation (TAI) improves QoL and patient independency with a significant reduction of time spent for defecation and daily bowel program. History of urinary infections predicts the choice of using TAI. Patient-reported efficacy of colostomy alone or in combination with other surgeries appears evident in terms of patient's satisfaction and QoL over time. Nonetheless, perioperative and late complications can occur and may result in reduced acceptability over time.

CONCLUSIONS

Evidence is somehow weak and mainly reported in SCI. The systematic use of assistive interventions does not reduce the need of conservative or invasive approaches. Studies are needed on the role of bowel management in protecting patients from complications secondary to NBD in long term follow-ups.

Effects of sacral nerve electrical stimulation on 5‑HT and 5‑HT3AR/5‑HT4R levels in the colon and sacral cord of acute spinal cord injury rat models

Spinal cord injury (SCI) often leads to defecation dysfunction. Sacral nerve electrical stimulation (SNS) therapy could improve defecation function. The present study aimed to assess SNS therapy, with regard to the levels of serotonin (5-HT) and its receptors (5-HT3AR and 5-HT4R) in the colon and sacral cord, a rat model of acute severe SCI was used. This rat model was made using the New York University Impactor device. Model rats were randomized to the SCI and SNS (electrical stimulation on the S3 nerve) groups. After 14 days of treatment, enteric transmission function was assessed. 5-HT and 5-HT3AR/5-HT4R were measured by ELISA, quantitative PCR, immunohistochemistry and western blotting. In SCI rats, SNS significantly increased the quantity of feces, shortened the time to the first fecal passage, and improved fecal texture and colon histology. SNS elevated 5-HT contents in the colon and spinal cord, and enhanced 5-HT3AR/5-HT4R protein expression and distribution in the colonic myenteric plexus and mucosa, sacral intermediolateral nucleus and dorsal horn. SNS upregulated the relative expression levels of 5-HT3AR/5-HT4R mRNA and protein in the colon and spinal cord. SNS can improve defecation and accelerate the recovery of colonic transmission functions in rat models of acute SCI. These effects involved upregulation of the 5-HT/5-HT3AR/5-HT4R axes.

Electrical Colon Stimulation Reflexively Increases Colonic Activity

OBJECTIVES

Most individuals with spinal cord injury have neurogenic bowel dysfunction, which includes slowed colonic motility and has a significant impact on their health and quality of life. Bowel management typically includes mechanical rectal distension to evoke a recto-colic reflex and promote bowel emptying. Electrical stimulation could replace this mechanical distension. The purpose of this study was to determine the feasibility of evoking colonic activity using electrical stimulation.

MATERIALS AND METHODS

Acute experiments were conducted in eight neural-intact cats under chloralose anesthesia. Patterned electrical stimulation was administered via electrodes placed on the surface of the distal colon or proximal colon. Distal and proximal colon pressures were measured using saline-filled balloon catheters. Outcome measures included peak colonic pressure; time to onset of response; and time to peak pressure compared to baseline without stimulation.

RESULTS

Stimulation elicited colonic activity in all animals. Peak colon pressures were 15 ± 28 cmH₂ O and were proportional to stimulation amplitudes. Time to onset and time to peak pressure were 13 ± 19 s and 37 ± 49 s, respectively, and were not significantly affected by stimulus parameters. Proximal colon stimulation only resulted in pressure responses from the proximal colon, but distal colon stimulation resulted in both proximal and distal responses in 40% of trials. Adding isoflurane anesthesia removed this proximal response to distal stimulation.

CONCLUSIONS

Distal colon stimulation evoked colonic activity. The dependence of this response on stimulation location and anesthesia suggests that responses were reflex mediated. Colonic stimulation may have the potential to improve colonic motility for individuals with neurogenic bowel dysfunction.

Neurogenic bowel dysfunction in patients with multiple sclerosis: prevalence, impact, and management strategies

Bowel dysfunction in patients with multiple sclerosis (MS) is highly prevalent. Constipation and fecal incontinence can coexist and alternate, impacting on the patient's quality of life and social interactions, as well as burdening the caregivers. The cost for the health care providers is also significant, with increased number of hospital admissions, treatment-related costs, and hospital appointments. The origin is multifactorial, and includes alteration of neurological pathways, polypharmacy, behavioral elements, and ability to access the toilet. Every patient with MS should be sensitively questioned about bowel function, and red flag symptoms should prompt adequate investigations. Manipulation of life style factors and establishment of a bowel regime should be attempted in the first place, and if this fails, other measures such as biofeedback and transanal irrigation should be included. A stoma can improve quality of life, and is not necessarily a last-ditch option. Antegrade colonic enemas can also be an effective option, whilst neuromodulation has not proved its role yet. Effective treatment of bowel dysfunction improves quality of life, reduces incidence of urinary tract infection, and reduces health care costs.

A systematic review of clinical studies on electrical stimulation therapy for patients with neurogenic bowel dysfunction after spinal cord injury

BACKGROUND

This study aimed to perform a systematic literature review of the clinical trial evidence on electrical stimulation for the treatment of neurogenic bowel dysfunction (NBD) after spinal cord injury (SCI).

METHODS

Systematic electronic searches were carried out in the PubMed/Medline, EMBASE, Cochrane Central Register of Controlled Trials, and China National Knowledge Infrastructure databases, along with the reference lists in the include studies. Studies were eligible for inclusion if they adopted a controlled clinical design based on human population, the patients suffered from spinal cord injury, the main outcomes were the disorders of bowel function and the intervention was electrical stimulation. Also, the language was limited to English and Chinese.

RESULTS

Eleven studies were included in this systematic review, comprising transcutaneous electrical stimulation, transrectal bowel stimulation, sacral nerve stimulation, intravesical electrical stimulation, etc. Of the 11 studies, 3 were randomized controlled trials, 8 were controlled before-and-after trials. The quality of the included studies was moderate bias risk. Most studies revealed that the electrical stimulation was beneficial for the patient with NBD after SCI.

CONCLUSIONS

Only 11 small clinical studies with 298 participants have evaluated the efficacy of electrical stimulation for NBD after SCI. Although some studies showed electrical stimulation was benefit for the patient with NBD after SCI, there was currently not enough evidence to support the use of electrical stimulation could improve the clinical symptoms of those patients. Thus, well-designed randomized controlled trials with larger patient population are warranted to establish its benefit in clinical practice in the future.

Bowel Dysfunction in Spinal Cord Injury

PURPOSE OF REVIEW

To evaluate and report current evidence regarding the management of bowel dysfunction in spinal cord injury. There is a paucity of high-quality large studies on which to base management advice.

RECENT FINDINGS

Recent research has focused on defining the nature of symptomatology of bowel dysfunction in SCI and describing the effects on quality of life and social interactions. Technical aspects of colonoscopy have received attention, and aspects of understanding the pathophysiology in relation to both neural and non-neural dysfunction have been studied. There has been refinement and expansion of the pharmacological and non-pharmacological treatment options for bowel dysfunction in SCI. Management of bowel dysfunction in SCI requires a comprehensive and individualized approach, encompassing lifestyle, toileting routine, stimulation, diet, medications, and surgery. Further high-quality research is required to inform best practice.

Chronic refractory constipation due to neurogenic bowel dysfunction can be successfully treated by sacral neurostimulation

INTRODUCTION

In the last few decades, sacral neurostimulation (SNS) has proven to be an effective treatment option for functional bowel disorders. Experience concerning the role of SNS in the treatment of chronic constipation due to neurogenic bowel dysfunction (NBD) however is limited.

METHODS

In this report, we present the case of a 44-year old patient, with chronic refractory neurogenic constipation after a spontaneous cerebral hemorrhage, who was treated with SNS.

RESULTS

Prior to treatment with SNS, the Constipation Scoring System showed a score of 22/30. Three months after SNS implantation, this score was reduced to 5/30. Patient had successful evacuation of stool every one to two days. Medication could be reduced to 15 drops of picosulphate per day. Patient experienced a significant improvement in quality of life.

CONCLUSIONS

We believe that SNS could offer a safe, effective and relatively cost-effective treatment for patients with NBD refractory to conservative treatment.

Sensors Selection for Continuous Monitoring of Bowel State and Activity

New research and diagnosis tools are needed to continuously measure bowel state and activity. We investigated functionality of several sensors in vivo and in vitro. Five sensor types, including pressure, infrared, color, conductivity and capacitance, were tested to validate functionality inside the colon. Initial wired prototypes were tested and calibrated in benchtop testing and then inserted intraluminally into pig colon and rectum in three acute surgical procedures. The results from both benchtop and in-vivo testing correlate and indicate that pressure, conductivity, and capacitance measurements could provide information on the state of the bowel and its activity.

Peripheral and Sacral Neuromodulation in the Treatment of Neurogenic Lower Urinary Tract Dysfunction

Sacral and peripheral neuromodulation are minimally invasive surgical procedures that are third-line therapy options for the treatment of patients with idiopathic overactive bladder syndrome. There has been interest in their efficacy in the management of neurogenic lower urinary tract dysfunction (NLUTD). Contemporary data suggest promising outcomes for urinary and bowel symptoms in carefully selected patients with spinal cord injury and/or multiple sclerosis. This article reviews the current literature regarding urinary and bowel outcomes in patients with NLUTD and also discusses contemporary studies that suggest that treatment during particular stages of neurologic injury may prevent long-term urinary sequelae.

Electrical Stimulation and Motor Recovery

In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as “neurons that fire together, wire together.” This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical stimulation (FES) has long been used to activate sacral nerves to treat bladder and pelvic dysfunction and to augment motor function. In theory, FES should facilitate synaptic formation and motor recovery after regenerative therapies. Upcoming clinical trials provide unique opportunities to test the theory.