Efficacy of a Single,Percutaneous, Across Midline,Octrode® Lead Using a “Midline Anchoring” Technique in the Treatment of Chronic Low Back and/or Lower Extremity Pain: A Retrospective Study

Introduction. Spinal cord stimulation is a widely used treatment modality for chronic pain, especially failed back surgery syndrome. However, migration of the lead or leads, coverage of axial pain, and the selection of an optimal system configuration continue to be subjects for serious debate. Materials and Methods. A retrospective study of the use of the method of “midline anchoring” of a single Octrode® lead, in 54 patients with low back and/or lower extremity pain, was done to assess the efficacy of this technique. Results. During the study period of 9.3 months, only a 4% revision rate was reported. Reduction in pain of more than 50% and individual patient satisfaction scores were very high (85% and 87%, respectively). Successful bilateral pain coverage was obtained with a single Octrode® lead. The lower extremities and buttocks area were captured in 89% of the patients. Axial pain coverage was achieved in the majority of the patients, with 71% reporting adequate coverage of the upper lumbar spine. A “guarded cathode” array was used in the vast majority of the cases, with a relatively low position of the lead. Conclusions. “Midline anchoring” of the spinal cord stimulation lead is an effective implantation technique, allowing the use of a single, percutaneous, Octrode® lead, while preventing lead migration and allowing capture of axial and lower extremity pain, unilateral as well as bilateral. This study revives the idea of a single lead as a possible optimal configuration.     

A New and Alternative Leads Positioning for Complex Regional Pain Syndrome Treatment: Paraforaminal Stimulation

We present a case of a female patient suffering from type I complex regional pain syndrome (CRPS) who developed “mirror imaging” of her CRPS and was successfully treated with dual spinal cord stimulation (SCS) in the paraforaminal epidural space. This patient initially had unilateral pain that was unsuccessfully treated with midline SCS and single‐lead lateral epidural lead placement “paraforaminally.” One year later, because we believed that paraforaminal stimulation would preferentially stimulate primary sensitized afferents innervating the painful area, we reperformed SCS with two leads positioned laterally and paraforaminally close to the roots within the epidural space. After repositioning and after 1 year of paraforaminal stimulation, there was significant improvement in the patient's symptoms, resolving all unilateral and “mirrored” symptoms. We conclude that paraforaminal stimulation may be a valid therapeutic option for the treatment of CRPS.     

Incidence and Risk Factors for Spinal Cord Stimulator Lead Migration With or Without Loss of Efficacy: A Retrospective Review of 91 Consecutive Thoracic Lead Implants

ObjectiveLead migration after spinal cord stimulator (SCS) implant is a commonly reported complication and the most common reason for revision surgery in cases of loss of efficacy. The primary aims of this study are to describe the incidence and degree of lead migration in the subacute postoperative period after SCS implant and to report potential risk factors for lead migration.Materials and MethodsWe performed a retrospective chart review of all patients at a single academic center who received an SCS implant from January 1, 2020, to December 31, 2020. Information on patient (age, sex, weight, and height) and operative factors (device manufacturer, epidural access level and method, and implantable pulse generator location) were extracted from medical records. Intraoperative imaging was compared to subacute follow-up imaging obtained less than 20 days postimplant to measure lead migration distance. Regression models were fitted to determine associations between lead migration distance and potential clinical risk factors.ResultsA total of 91 cases (182 leads) were included in the study. Within 20 days of implantation, 88.5% of leads had migrated (86.3% caudal and 2.2% cephalad). Mean migration distance for leads with caudal migration only was 12.34 ± 12.19 mm based on anteroposterior radiographs and 16.95 ± 15.68 mm on lateral radiographs. There was an association of greater caudal lead migration as patient body mass index increased (β-coefficient 0.07 [95% confidence interval 0.01–0.13], p = 0.031). Within the entire cohort, one patient (1.1%) required lead revision for loss of efficacy.ConclusionsIn the subacute postoperative period after SCS implant, the majority of SCS leads migrated caudally with an average of two lead contacts. Knowledge of this expected migration and risk factors can better inform implanting physicians intraoperatively when deciding final lead placement location. The finding of high likelihood of caudal lead migration in the subacute postoperative period brings the need for a well-designed prospective study to the forefront of our field. This will allow implanting providers to make well-informed decisions for intraoperative lead placement.     

Subcutaneous Peripheral Nerve Stimulation with Inter‐lead Stimulation for Axial Neck and Low Back Pain: Case Series and Review of the Literature

Objectives: While pain in the extremities often responds to treatment using spinal cord stimulation (SCS), axial pain is notoriously refractory to SCS. Interest in subcutaneous peripheral nerve stimulation (SQ PNS) as an alternative to SCS has emerged, but the most appropriate electrode locations and neurostimulator programming techniques are not yet clear. Methods: A retrospective review was conducted of consecutive patients evaluated from August 2009 to December 2010 who had undergone trial of SQ PNS with inter‐lead stimulation for axial spine pain. Patients proceeding to implant were followed postoperatively with routine clinical visits and a survey form at last follow‐up. Ultrasound was used intraoperatively to ensure placement of electrodes at the appropriate depth in patients with larger body mass index. Primary outcome was patient‐reported pain relief at last follow‐up. Literature review was conducted by searching MEDLINE (1948–present) and through an unstructured review by the authors. Results: Ten patients underwent trial of SQ PNS and six proceeded to permanent implantation. Fifty percent (3/6) of implanted patients preferred neurostimulation programming that included inter‐lead stimulation (“cross‐talk”). Average duration of postoperative follow‐up was 4.5 months (range 2–9 months). Average patient‐reported pain relief at last follow‐up was 45% (range 20–80%). One patient required re‐operation for migration. Patients not proceeding to implant had paresthesia coverage but no analgesia. Conclusion: SQ PNS is a promising therapy for axial neck and back pain based on a small cohort of patients. Ultrasound was useful to assist with electrode placement at the most appropriate depth beneath the skin. While inter‐lead stimulation has been preferred by patients in published reports, we did not find it clearly influenced pain relief. Future investigations should include a randomized, controlled study design, as well as defined implantation technique and neurostimulator programming algorithms.     

Prevention of Mechanical Failures in Implanted Spinal Cord Stimulation Systems

Introduction. Spinal cord stimulation (SCS) is an effective procedure for the treatment of neuropathic extremity pain, with success rates approaching 70%. However, mechanical failures, including breakage and migration, can significantly limit the long‐term effectiveness of SCS. A systematic analysis of surgical techniques was undertaken by a consensus group, coupled with extensive in vivo and in vitro biomechanical testing of system components. Methods. A computer model based on morphometric data was used to predict movement in a standard SCS system between an anchored lead and pulse generator placed in various locations. These displacements were then used to determine a realistic range of forces exerted on components of the SCS system. Laboratory fixtures were constructed to subject leads and anchors to repetitive stresses until failure occurred. An in vivo sheep model also was used to determine system compliances and failure thresholds in a biologically realistic setting. A panel of experienced implanters then interpreted the results and related them to clinical observations. Results. Use of a soft silastic anchor pushed through the fascia to provide a larger bend radius for the lead was associated with a time to failure 65 times longer than an anchored but unsupported lead. In addition, failures of surgical paddle leads occurred when used with an anchor, whereas without an anchor, no failures occurred to 1 million cycles. Based on these findings, the panel recommended a paramedian approach, abdominal pulse generator placement, maximizing bend radius by pushing the anchor through the fascia, and anchoring of the extension connector near the lead anchor. Discussion. Several factors are important in longevity of SCS systems. We discovered that technical factors can make a large difference in SCS reliability and that strict attention to these “best practices” will provide the best chance for maintaining the integrity of SCS systems over the long term.     

Deep brain stimulation lead fixation after Stimloc failure

We report a method for deep brain stimulation (DBS) lead fixation in the event that the primary anchoring device fails to function effectively. The method involves the application of a titanium microplate to secure the lead to the skull, thereby providing a fast and reliable “rescue” mechanism for lead fixation. This method can supplement any burr hole cap and fixation method. Furthermore, this method has several advantages over removal and replacement of the primary anchor, such as a lower possibility of lead migration, faster procedural time, and cost-effectiveness.     

Applicability and Validity of an e-Health Tool for the Appropriate Referral and Selection of Patients With Chronic Pain for Spinal Cord Stimulation: Results From a European Retrospective Study

ObjectivesTo support rational decision-making on spinal cord stimulation (SCS), a European expert panel developed an educational e-health tool using the RAND/University of California at Los Angeles Appropriateness Method. This retrospective study aimed to determine the applicability and validity of the tool using data from patients for whom SCS had been considered.Materials and MethodsA total of 12 European implant centers retrieved data from 25 to 50 consecutive patients for whom SCS was considered in 2018–2019. For each patient, data were captured on the clinical and psychosocial variables included in the e-health tool, center decisions on SCS, and patient outcomes. Patient outcomes included global perception of effect by the patient and observer, and pain reduction (numeric pain rating scale) at six-month follow-up.ResultsIn total, 483 patients were included, of whom 133 received a direct implant, 258 received an implant after a positive trial, 32 had a negative trial, and 60 did not receive SCS for reasons other than a negative trial. The most frequent indication was persistent spinal pain syndrome type 1 and type 2 (74%), followed by neuropathic pain syndromes (13%), complex regional pain syndrome (12%), and ischemic pain syndromes (0.8%). Data on the clinical and psychosocial variables were complete for 95% and 93% of patients, respectively, and missing data did not have a significant impact on the study outcomes. In patients who had received SCS, panel recommendations were significantly associated with patient outcomes (p < 0.001 for all measures). Substantial improvement ranged from 25% if the e-health tool outcome was “not recommended” to 83% if SCS was “strongly recommended”. In patients who underwent a trial (N = 290), there was 3% of trial failure when SCS was ”strongly recommended” vs 46% when SCS was ”not recommended”.ConclusionsRetrospective application of the e-health tool on patient data showed a strong relationship between the panel recommendations and both SCS trial results and treatment outcomes.     

Lead and Pulse Generator Migration After Spinal Cord Stimulation Implantation: Insights From an Analysis of 7322 Patients

ObjectivesLead migration (LM) after spinal cord stimulation (SCS) implantation surgery is the most common device-related complication. Our study of lead and implantable pulse generator (IPG) migration using a large administrative claims data base aims to understand rates, risk factors, and outcomes after SCS implantation.Materials and MethodsThis retrospective cohort study used the IBM® MarketScan® (Armonk, NY) Commercial and Medicare Supplemental Databases from 2016 to 2018. Adult patients who underwent SCS surgical procedures with at least 90 days of follow-up were identified using Current Procedural Terminology (CPT®) codes. Patients with LM and IPG migration after SCS surgery were identified using the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10 CM) codes. Patients who underwent revision surgery after SCS implantation were identified using the CPT codes and ICD-10 CM codes. In addition, patient characteristics associated with LM or IPG migration, the temporal relationship of migration diagnosis, and revision surgery were evaluated in the cohort. Continuous outcomes were compared between groups using the two-sample Student t-test. The Fisher exact test was used to compare categorical outcomes between groups.ResultsA total of 7322 patients (64.4% percutaneous SCS) underwent SCS surgery during the study period. A total of 141 patients (1.9%) had LM or IPG migration. Of those, 116 patients (1.6%) had LM only; 18 patients (0.2%) had IPG migration; and seven patients (0.1%) had LM and IPG migration. The mean duration for migration diagnosis after initial SCS implantation was 168 (±163.1) days. The mean duration to revision surgery after the migration diagnosis was 12.3 (±35.2) days only. Most patients with migration (105, 74.5%) underwent revision surgery. Only younger age (p = 0.02) was associated with migration in this study.ConclusionsLM and pulse generator migration that required revision surgery occurred in a small proportion of patients who underwent SCS surgical procedures.     

Theoretical Investigation Into Longitudinal Cathodal Field Steering in Spinal Cord Stimulation

Objective. When using spinal cord stimulation (SCS) for chronic pain management, precise longitudinal positioning of the cathode is crucial to generate an electrical field capable of targeting the neural elements involved in pain relief. Presently used methods have a poor spatial resolution and lack postoperative flexibility needed for fine tuning and reprogramming the stimulation field after lead displacement or changes in pain pattern. We describe in this article a new method, “electrical field steering,” to control paresthesia in SCS. The method takes advantage of newer stimulator design and a programming technique allowing for “continuous” adjustment of contact combination while controlling stimulation current for each contact separately. Method. Using computer modeling we examined how stimulation of dorsal column (DC) and dorsal root (DR) fibers was influenced by changing the current ratio of the cathodes of a dual (––) and a guarded dual cathode (+––+) configuration programmed on a percutaneous lead with 9 and 4 mm center‐to‐center contact spacing. Results. A cathodal current ratio could be found for which DC or DR fiber recruitment and thus, most likely, paresthesia coverage was maximized. The DR threshold profiles shifted longitudinally, thus following the shift in the electrical field during steering. The profiles had a constant shape when the contact spacing was small and a varying shape for wider contact separation. Generally, the wider contact separation provided less DC and more DR fiber recruitment. Conclusions. By means of cathodal steering on a longitudinal contact array, the group of excited DC and DR fibers, and thus paresthesia coverage, can be controlled when using SCS. With widely spaced contacts, superposition of the electrical field from each steering contact is limited. To precisely control segmental paresthesia (DR stimulation), a small contact spacing is necessary.     

Percutaneous Implanted Paddle Lead for Spinal Cord Stimulation: Technical Considerations and Long‐Term Follow‐Up

Objectives: Spinal cord stimulation (SCS) is an established method for treatment of chronic pain. Cylindrical‐type leads can be implanted percutaneously. In contrast, paddle leads (lamitrode) require more invasive surgery (i.e., laminotomy or laminectomy) for placement into the epidural space, thereby offering several advantages over percutaneous leads (octrode), including less lead migration and better paresthesia coverage. The goal of this study was to prospectively demonstrate the safety and efficacy of a percutaneous paddle lead for SCS. Materials and Methods: This prospective trial enrolled 81 patients. The mean age was 57 years (range 27–82 years) with an almost equal sex distribution (male 47%, female 53%). Most patients (90%) had failed back surgery syndrome combined with lower extremity pain and lower back pain. A percutaneous paddle lead was implanted using a novel introduction system for percutaneous implantation. All implantations were performed under local anesthesia. Prior to the final implantation of the impulse generator, all patients underwent seven days of trial stimulation with pain assessment using a visual analog scale (VAS). The median follow‐up was 12 months. Results: The data showed favorable clinical outcomes for paresthesia coverage and pain reduction (median VAS 8.4 vs. 2.3), with a risk profile comparable with known percutaneous techniques. Compared with the published data (2–22%), the lead migration rate in this study was low (2.5%). No perioperative complications occurred. Conclusions: This new, minimally invasive percutaneous paddle lead is effective and safe, with a low migration rate. Placement can be done under local anesthesia, allowing an intraoperative assessment of the paresthesia coverage in terms of pain relief. This approach is less invasive and offers a faster and more comfortable procedure compared with laminotomy or laminectomy.     

Electrical Stimulation for Cerebral Vasospasm After Subarachnoid Hemorrhage: A Systematic Review

ObjectivesCerebral vasospasm is a severe and potentially lethal complication in patients with subarachnoid hemorrhage (SAH). Its pathogenesis is still not completely understood. The efficacy of current treatments, such as triple-H therapy or calcium channel blockers, is unsatisfactory, and a new therapy model would therefore be valuable. Electrical stimulation may have a considerable influence on cerebrovascular innervation. This systematic review gives an overview of the studies that have applied electrical stimulation in models of cerebral vasospasm.Materials and MethodsWe performed a systematic review of the literature, searching PubMed and Ovid Embase with the keywords “electric stimulation,” “cerebral vasospasm,” “subarachnoid hemorrhage,” “sympathetic,” and “parasympathetic.” Additional papers were identified from the reference lists of the articles identified in the literature search.ResultsIncreased cerebral blood flow (CBF) is a widely observed effect of spinal cord stimulation and sphenopalatine ganglion stimulation in models of physiological conditions or experimental cerebral vasospasm. Most studies were conducted in animals, 15 under physiological conditions and 11 in animals with SAH. Eight studies in humans were identified that examined the stimulation effect on CBF under physiological conditions. Only two studies looked at patients after SAH: one applied spinal cord stimulation (SCS) and the other transcutaneous electrical neurostimulation. Different mechanisms leading to stimulation-induced CBF increase that were discussed included “reversible functional sympathectomy,” activation of brainstem vasomotor centers, involvement of central ascending pathways, release of neurohumoral factors, and interaction with sympathetic, parasympathetic, and trigeminal innervation. The results indicate that electrical stimulation is a promising procedure for prevention and treatment of cerebral vasospasm.ConclusionElectrical stimulation, especially SCS and sphenopalatine ganglion stimulation, is a promising adjunct for existing therapies for vasospasm after SAH. Further experiments and prospective clinical studies are needed to establish its potential usefulness as a therapy or prevention option.     

Lead Migration in Neuromodulation

We describe a simple technique of securing surgically implanted leads for spinal cord (SCS), dorsal root ganglion (DRG) and occipital nerve stimulation (ONS), for both primary surgical implantation and correcting lead migration. This technique could also be adapted for securing percutaneously implanted leads. Thirty-nine patients underwent neurosurgical implantation of SCS, DRG, and ONS devices utilizing titanium mini-plates to obtain secure anchorage of leads to adjacent laminae close to their exit point from the epidural space, thereby minimizing the risk of further lead migration or electrode displacement. There were no cases of primary or recurrent lead migration in any patient undergoing lead placement using mini-plate anchorage. The technique appears to offer a reliable means of preventing post-operative lead migration in a variety of spinal and extra-cranial neuromodulation implants.     

“Leisure-Links”

This article describes research undertaken to assess the need for a community leisure service in Tower Hamlets, part of London's East End. The results replicate the findings of other researchers; that many people with mental handicaps, though “living” in the community, remain isolated from the “community” in its widest sense. People in this study spent the majority of their free time engaged in housebound, solitary, passive, and family oriented activities. Pursuits which did involve “going out” tended to be for groups, such as attending clubs or sports activities. It was found that 84 per cent of respondents, that is, potential consumers, felt they would like to take part in leisure activities that they were not pursuing at the time of the study. The development of Tower Hamlets “Leisure-Links” scheme is described, highlighting features of the scheme which distinguish it from other similar initiatives. Applications for funding are outlined.     

How Should we Use Multicolumn Spinal Cord Stimulation to Optimize Back Pain Spatial Neural Targeting? A Prospective,Multicenter, Randomized,Double-Blind,Controlled Trial (ESTIMET Study)

BackgroundRecent studies have highlighted multicolumn spinal cord stimulation (SCS) efficacy, hypothesizing that optimized spatial neural targeting provided by new-generation SCS lead design or its multicolumn programming abilities could represent an opportunity to better address chronic back pain (BP).ObjectiveTo compare multicolumn vs. monocolumn programming on clinical outcomes of refractory postoperative chronic BP patients implanted with SCS using multicolumn surgical lead.Materials and MethodsTwelve centers included 115 patients in a multicenter, randomized, double-blind, controlled trial. After randomization, leads were programmed using only one or several columns. The primary outcome was change in BP visual analogic scale (VAS) at six months. All patients were then programmed using the full potential of the lead up until 12-months follow-up.ResultsAt six months, there was no significant difference in clinical outcomes whether the SCS was programmed using a mono or a multicolumn program. At 12 months, in all patients having been receiving multicolumn SCS for at least six months (n = 97), VAS decreases were significant for global pain (45.1%), leg pain (55.8%), and BP (41.5%) compared with baseline (p < 0.0001).ConclusionThe ESTIMET study confirms the significant benefit experienced on chronic BP by patients implanted with multicolumn SCS, independently from multicolumn lead programming. These good clinical outcomes might result from the specific architecture of the multicolumn lead, giving the opportunity to select initially the best column on a multicolumn grid and to optimize neural targeting with low-energy requirements. However, involving more columns than one does not appear necessary, once initial spatial targeting of the “sweet spot” has been achieved. Our findings suggest that this spatial concept could also be transposed to cylindrical leads, which have drastically improved their capability to shape the electrical field, and might be combined with temporal resolution using SCS new modalities.     

Embedded ensemble encoding hypothesis: The role of the “Prepared” cell

We here reconsider current theories of neural ensembles in the context of recent discoveries about neuronal dendritic physiology. The key physiological observation is that the dendritic plateau potential produces sustained depolarization of the cell body (amplitude 10–20 mV, duration 200–500 ms). Our central hypothesis is that synaptically‐evoked dendritic plateau potentials lead to a prepared state of a neuron that favors spike generation. The plateau both depolarizes the cell toward spike threshold, and provides faster response to inputs through a shortened membrane time constant. As a result, the speed of synaptic‐to‐action potential (AP) transfer is faster during the plateau phase. Our hypothesis relates the changes from “resting” to “depolarized” neuronal state to changes in ensemble dynamics and in network information flow. The plateau provides the Prepared state (sustained depolarization of the cell body) with a time window of 200–500 ms. During this time, a neuron can tune into ongoing network activity and synchronize spiking with other neurons to provide a coordinated Active state (robust firing of somatic APs), which would permit “binding” of signals through coordination of neural activity across a population. The transient Active ensemble of neurons is embedded in the longer‐lasting Prepared ensemble of neurons. We hypothesize that “embedded ensemble encoding” may be an important organizing principle in networks of neurons.     

“Selected truth”

Professional staff in the National Health Service tend to assume without question that the patients they meet are genuine, honest, and well-intentioned in the problems that they present. The same applies to the parents and relatives of patients, and to professional associates. The large majority are, so that any rare exceptions appear almost incredible. In this respect interviews with doctors and other health workers differ from those with lawyers and the police where the veracity and goodwill of the client is not automatically taken for granted. Downright deliberate dishonesty or premeditated manipulation of truth on the part of patients, their relatives, and people caring for them may be construed as reflecting some personality or psychiatric disorder. Milder forms and shades of “near truth”, “selected truth”, “graduated truth”, “white lies”, “exaggerated facts”, and data chosen for maximum impact, are more frequent and are probably not always suspected or detected. In all communications between people, degrees of licence and flexibility are found, and are institutionalised in different societies and cultures. For example, it has been good manners in Britain not to be too outspoken or blunt, and to use understatement. This is reminiscent of Voltaire's “Speech was given to man to conceal his thoughts.” The term “graduated truth” is used in medical work when it is thought to be in the interests of the patient to deliberately and knowingly conceal or modify the truth. This paper considers some facets of services for mentally handicapped people where “graduated truth” is used in practice. These are: selectivity of data; differential behaviour; fabrication, fantasy and make-believe; and patient management.     

A New Spinal Cord Stimulation System Effectively Relieves Chronic,Intractable Pain: A Multicenter Prospective Clinical Study

Objectives. A prospective, open label, multicenter clinical trial confirmed the functionality of a new spinal cord stimulation (SCS) system for the treatment of chronic, intractable pain of the trunk and/or limbs. Materials and Methods. Sixty‐five subjects tested a rechargeable 16‐channel SCS system with individual current control of each contact on one or two percutaneous eight‐contact epidural leads. After baseline measurements, subjects were tracked on pain ratings and complication rates for up to 18 months. Results. After a trial period, 75% of subjects underwent permanent implantation of the entire SCS system. More than one‐half the implanted subjects experienced 50% or greater relief of pain after permanent implantation; some subjects reported relief of 90% or more of their pain. The most common complications after permanent implantation were lead migration, uncomfortable stimulation, and component failure; most resolved after reprogramming or device replacement. Conclusions. The new SCS system provided good pain relief to a majority of subjects, and the results confirm a favorable safety and efficacy profile for the SCS system.     

Motor unit estimates obtained using the new “MUESA” method

Motor unit number estimates were obtained from the extensor digitorum brevis and thenar muscles using a new method called MUESA. MUESA is distinguished from other estimation methods in the manner in which it deals with probabilistic motor unit activation, which is more commonly referred to as “alternation.” Because of “alternation,” incremental increases in the observed muscle potentials often cannot be interpreted in terms of the successive activation of single motor units. In the MUESA method, the nerve is subjected to a number of constant-intensity stimulus trains, and the resultant muscle response sequences are decomposed into their constituent motor unit action potentials. In general, if a stimulus train results in the probabilistic activation of n motor units, we can expect to see up to 2ⁿ different potentials, with each potential representing a unique combination of active and/or inactive motor units. If all 2ⁿ potentials are indeed observed, the decomposition of the observed potential sequence into its constituent motor unit action potentials is very straightforward. For the majority of the cases in which the number of observed potentials is not an integer power of 2, we have developed a novel decomposition method based on the analysis of the relative firing rates of the motor units. © 1996 John Wiley & Sons, Inc.     

Rare Side‐effects during Spinal Cord Stimulation: Gastrointestinal Symptoms

In current medical literature, most reported complications during spinal cord stimulation (SCS) concern technical problems, such as malfunction, migration or breakage of the lead, or internal pulse generator dysfunction, while reports about side‐effects caused by SCS are rare. In this clinical report, we describe uncommon and unexplained gastrointestinal (GI) side‐effects of constipation, abdominal pain, and distension during SCS in a patient suffering for chronic neuropathic pain caused by failed back surgery syndrome. These GI symptoms disappeared after suspension of SCS and were reduced if the stimulation settings were reduced below paresthesia threshold. The symptoms experienced by our patient could be related to a functional and reversible block of parasympathetic outflow in the GI system since SCS may involve not only dorsal horn structures but also somatic and visceral sensory afferents to these structures in an unpredictable way.     

The temporal signature of self: Temporal measures of resting‐state EEG predict self‐consciousness

The self is the core of our mental life. Previous investigations have demonstrated a strong neural overlap between self‐related activity and resting state activity. This suggests that information about self‐relatedness is encoded in our brain's spontaneous activity. The exact neuronal mechanisms of such “rest‐self containment,” however, remain unclear. The present EEG study investigated temporal measures of resting state EEG to relate them to self‐consciousness. This was obtained with the self‐consciousness scale (SCS) which measures Private, Public, and Social dimensions of self. We demonstrate positive correlations between Private self‐consciousness and three temporal measures of resting state activity: scale‐free activity as indexed by the power‐law exponent (PLE), the auto‐correlation window (ACW), and modulation index (MI). Specifically, higher PLE, longer ACW, and stronger MI were related to higher degrees of Private self‐consciousness. Finally, conducting eLORETA for spatial tomography, we found significant correlation of Private self‐consciousness with activity in cortical midline structures such as the perigenual anterior cingulate cortex and posterior cingulate cortex. These results were reinforced with a data‐driven analysis; a machine learning algorithm accurately predicted an individual as having a “high” or “low” Private self‐consciousness score based on these measures of the brain's spatiotemporal structure. In conclusion, our results demonstrate that Private self‐consciousness is related to the temporal structure of resting state activity as featured by temporal nestedness (PLE), temporal continuity (ACW), and temporal integration (MI). Our results support the hypothesis that self‐related information is temporally contained in the brain's resting state. “Rest‐self containment” can thus be featured by a temporal signature.