Spinal-cord stimulation in critical limb ischaemia: a randomised trial. ESES Study Group

Role of patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain: a comprehensive narrative review

Background/importance

Patient selection for spinal cord stimulation (SCS) therapy is crucial and is traditionally performed with clinical selection followed by a screening trial. The factors influencing patient selection and the importance of trialing have not been systematically evaluated.

Objective

We report a narrative review conducted to synthesize evidence regarding patient selection and the role of SCS trials.

Evidence review

Medline, EMBASE and Cochrane databases were searched for reports (any design) of SCS in adult patients, from their inception until March 30, 2022. Study selection and data extraction were carried out using DistillerSR. Data were organized into tables and narrative summaries, categorized by study design. Importance of patient variables and trialing was considered by looking at their influence on the long-term therapy success.

Findings

Among 7321 citations, 201 reports consisting of 60 systematic reviews, 36 randomized controlled trials (RCTs), 41 observational studies (OSs), 51 registry-based reports, and 13 case reports on complications during trialing were included. Based on RCTs and OSs, the median trial success rate was 72% and 82%, and therapy success was 65% and 61% at 12 months, respectively. Although several psychological and non-psychological determinants have been investigated, studies do not report a consistent approach to patient selection. Among psychological factors, untreated depression was associated with poor long-term outcomes, but the effect of others was inconsistent. Most RCTs except for chronic angina involved trialing and only one RCT compared patient selection with or without trial. The median (range) trial duration was 10 (0–30) and 7 (0–56) days among RCTs and OSs, respectively.

Conclusions

Due to lack of a consistent approach to identify responders for SCS therapy, trialing complements patient selection to exclude patients who do not find the therapy helpful and/or intolerant of the SCS system. However, more rigorous and large studies are necessary to better evaluate its role.

Non-surgical treatment for arterial leg ulcers: a narrative review

Objectives:

Arterial leg ulcers (ALUs) pose a considerable burden on patients and health services. The cornerstone of treatment is revascularisation; however, this is not always possible and does not necessarily guarantee ulcer healing. Alternative treatment options are therefore also important. This narrative review aims to summarise the evidence available for non-surgical treatment of ALUs, including topical therapy, pharmacological agents, therapeutic angiogenesis and devices.

Methods:

A literature search was performed in November 2020 to identify studies reporting data on the non-surgical management of ALUs. Prospective randomised controlled trials (RCTs), controlled clinical trials and meta-analyses that investigated conservative or medical interventions on patients with intractable ALUs, and which provided quantitative data on ulcer healing were included. Following screening, studies that met the inclusion criteria underwent a data extraction process and findings were synthesised and categorised narratively.

Results:

In total, 14 controlled trials were selected for inclusion and analysed based on experimental protocol and outcome measures.

Conclusion:

There is some evidence available for the use of short-term systemic prostanoids, ultrasound therapy and pneumatic compression. There are limitations to these options including side effects, patient tolerance due to pain and availability in clinical practice. Further research is needed to improve treatment options for this complex group.

A novel photosynthetic biologic topical gel for enhanced localized hyperoxygenation augments wound healing in peripheral artery disease

Peripheral artery disease and the associated ischemic wounds are substantial causes of global morbidity and mortality, affecting over 200 million people worldwide. Although advancements have been made in preventive, pharmacologic, and surgical strategies to treat this disease, ischemic wounds, a consequence of end-stage peripheral artery disease, remain a significant clinical and economic challenge. Synechococcus elongatus is a cyanobacterium that grows photoautotrophically and converts carbon dioxide and water into oxygen. We present a novel topical biologic gel containing S. elongatus that provides oxygen via photosynthesis to augment wound healing by rescuing ischemic tissues caused by peripheral artery disease. By using light rather than blood as a source of energy, our novel topical therapy significantly accelerated wound healing in two rodent ischemic wound models. This novel topical gel can be directly translated to clinical practice by using a localized, portable light source without interfering with patients' daily activities, demonstrating potential to generate a paradigm shift in treating ischemic wounds from peripheral artery disease. Its novelty, low production cost, and ease of clinical translatability can potentially impact the clinical care for millions of patients suffering from peripheral arterial disease.

Spinal cord stimulation in the treatment of peripheral vascular disease: a systematic review - revival of a promising therapeutic option?

INTRODUCTION

Peripheral vascular disease (PVD) is caused by a blood circulation disorder of the arteries and Critical Limb Ischemia (CLI) is the advanced state of PVD. For patients with surgically non-reconstructable CLI, Spinal Cord Stimulation (SCS) appears to be an alternative therapeutic option.

OBJECTIVE

The aim of our study was to investigate the efficacy of SCS in non-reconstructable CLI compared with the conservative treatment and re-appraise the existing literature in light of the recent advances in neuromodulation.

METHODS

We conducted a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, using electronic databases and reference lists for article retrieval.

RESULTS

A total of 404 records were identified and finally 6 randomised controlled trials (RCTs), a Cochrane review and a meta-analysis were included in our systematic review. The studies assessed the efficacy of tonic SCS in the treatment of patients with non-reconstructable CLI compared with the conservative treatment. There is moderate to high quality evidence suggesting, that tonic SCS has beneficial effects for patients suffering from non-reconstructable CLI in terms of limb salvage, pain relief, clinical improvement and quality of life. The contradictory conclusions of the two meta-analyses regarding the efficacy of SCS for limb salvage at 12 months refer rather to the magnitude of the beneficial effect than to the effect itself. So far, the current literature provides evidence about the traditional tonic SCS but there is a lack of studies investigating the efficacy of new waveforms in the treatment of non-reconstructable CLI.

CONCLUSION

SCS represents an alternative for PVD patients with non-reconstructable CLI and the existing literature provides encouraging clinical results, that should not be neglected. Instead, they should be re-appraised in light of the recent advances in neuromodulation with the emergence of novel waveform technologies and neuromodulation targets.

Outcomes of Conservative Treatment in Patients with Chronic Limb Threatening Ischaemia: A Systematic Review and Meta-Analysis

OBJECTIVE

Chronic limb threatening ischaemia (CLTI) is the most severe form of peripheral arterial disease. International guidelines recommend arterial revascularisation in patients with CLTI. However, these patients are often fragile elderly people with significant comorbidities, whose vascular anatomy is not always suitable for open or endovascular revascularisation. Recent studies have suggested acceptable outcomes of conservative treatment. A systematic review of the available literature was conducted to obtain best estimates of outcomes of conservative treatment in patients with CLTI.

DATA SOURCES

MEDLINE, Embase, and Cochrane Central.

REVIEW METHODS

A systematic review and meta-analysis was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. MEDLINE, Embase, and Cochrane Central were searched from inception until September 2019. All studies reporting on outcomes of conservative treatment for CLTI were considered. Study selection, data extraction, and risk of bias assessment were done by two investigators independently. Risk of bias was evaluated with a modified version of the Cochrane tool for observational studies. Outcomes of interest were all cause mortality, major amputation, and amputation free survival (AFS) after at least 12 months of follow up. A random effects model was used for meta-analyses.

RESULTS

Twenty-seven publications were included, consisting of 12 observational studies and 15 placebo arms from randomised clinical trials, totalling 1 642 patients. Most studies included patients with non-reconstructable CLTI. Overall study quality was moderate. The pooled 12 month all cause mortality rate in 14 studies comprising 1 003 patients was 18% (95% confidence interval [CI] 13 - 25, I² = 73%). The pooled major amputation rate from 14 studies comprising 755 patients was 27% (95% CI 20 - 36, I² = 65%) after one year, and pooled AFS rate after 12 months in 11 studies with 970 patients was 60% (95% CI 52 - 67, I² = 75%).

CONCLUSION

Conservative treatment for patients with CLTI may be considered and does not always result in loss of limb or patient demise. The results of this review can be used to inform patients with CLTI about conservative treatment as part of a shared decision making process.

Improving Limb Salvage for Chronic Limb-Threatening Ischemia With Spinal Cord Stimulation: A Retrospective Analysis

Introduction:

Chronic limb-threatening ischemia (CLTI) represents the most severe form of peripheral artery disease (PAD). Up to a third of CLTI patients are not eligible to receive first-line treatments such as bypass surgery or endovascular interventions. Epidural spinal cord stimulation (SCS) has been used as a method to improve microcirculatory blood flow and relieve ischemic pain in CTLI patients. The aim of the study was to evaluate limb salvage, ulcer closure, and clinical changes of SCS implanted CTLI patients at 1-year follow-up.

Methods:

Eligible patients had end-stage lower limb PAD unresponsive to medical therapy and not amenable to surgical reconstruction. Patients were candidates for amputation, but limb loss was not inevitable (Fontaine stage III and IV). Pain intensity and skin temperature in the ischemic area (visual analogue scale), quality of life (WHOQoL-BREF), and ankle/brachial blood pressure index (ABI) were recorded at routine follow-up visits. Data were analyzed retrospectively.

Results:

29 patients underwent SCS implantation at one vascular center. The minimum follow-up period was 30 months. Limb survival at 1-year follow-up was 97% (28/29) and 73% (11/15) had complete closure of limb ulcers. Pain intensity, skin temperature, and quality of life progressively improved up to 12 months after implant, with Fontaine stage III patients improving more substantially than Fontaine stage IV patients. SCS therapy did not affect ABI measurement. No complications related to the device or procedure occurred.

Conclusions:

SCS is a valid alternative in patients unsuitable for revascularization. The quality of results depends on both a strict selection of patients by vascular specialists and the frequency of follow-up controls. The therapy may be more beneficial in patients classified as Fontaine stage III.

Systematic Review of Research Methods and Reporting Quality of Randomized Clinical Trials of Spinal Cord Stimulation for Pain

This systematic review assessed design characteristics and reporting quality of published randomized clinical trials of spinal cord stimulation (SCS) for treatment of pain in adults and adolescents. The study protocol was registered with PROSPERO (CRD42018090412). Relevant articles were identified by searching the following databases through December 31, 2018: MEDLINE, Embase, WikiStim, The Cochrane Database of Systematic Reviews, and The Cochrane Central Register of Controlled Trials. Forty-six studies were included. Eighty-seven percent of articles identified a pain-related primary outcome. Secondary outcomes included physical functioning, health-related quality of life, and reductions in opioid use. Nineteen of the 46 studies prespecified adverse events as an outcome, with 4 assessing them as a primary outcome. Eleven studies stated that they blinded participants. Of these, only 5 were assessed as being adequately blinded. The number of participants enrolled was generally low (median 38) and study durations were short (median 12 weeks), particularly in studies of angina. Fifteen studies employed an intention-to-treat analysis, of which only seven specified a method to accommodate missing data. Review of these studies identified deficiencies in both reporting and methodology. The review's findings suggest areas for improving the design of future studies and increasing transparency of reporting. PERSPECTIVE: This article presents a systematic review of research methods and reporting quality of randomized clinical trials of SCS for the treatment of various pain complaints. The review identifies deficiencies in both methodology and reporting, which may inform the design of future studies and improve reporting standards.

Prevalence of smoking in adults with spinal cord stimulators: a systematic review and meta-analysis

BACKGROUND

Smoking adversely impacts pain-related outcomes of spinal cord stimulation (SCS). However, the proportion of SCS patients at risk of worse outcomes is limited by an incomplete knowledge of smoking prevalence in this population. Thus, the primary aim of this systematic review is to determine the prevalence of smoking in adults with chronic pain treated with SCS.

METHODS

A comprehensive search of databases from 1 January 1980 to 3 January 2019 was conducted. Eligible study designs included (1) randomized trials; (2) prospective and retrospective cohort studies; and (3) cross-sectional studies. The risk of bias was assessed using a tool specifically developed for prevalence studies. A total of 1619 records were screened, 19 studies met inclusion criteria, and the total number of participants was 10 838.

RESULTS

Thirteen studies had low or moderate risk of bias, and six had a high risk of bias. All 19 studies reported smoking status and the pooled prevalence was 38% (95% CI 30% to 47%). The pooled prevalence in 6 studies of peripheral vascular diseases was 56% (95% CI 42% to 69%), the pooled prevalence of smoking in 11 studies of lumbar spine diagnoses was 28% (95% CI 20% to 36%) and the pooled prevalence in 2 studies of refractory angina was 44% (95% CI 31% to 58%).

CONCLUSIONS

The estimated prevalence of smoking in SCS patients is 2.5 times greater than the general population. Future research should focus on development, testing and deployment of tailored smoking cessation treatments for SCS patients.

Limb salvage in diabetic patients with no-option critical limb ischemia: outcomes of a specialized center experience

Objective: To describe the characteristics, the management and the outcome of a consecutive series of patients with diabetic foot lesions (DF) and no-option critical limb ischemia (CLI) treated with a multidimensional, interdisciplinary approach in a dedicated center. Research Design and Methods: The prospective database of the Diabetic Foot Unit of the Maria Cecilia Hospital (Cotignola, Italy) collects medical history, risk factors, chemistry values, angiographic data, characteristic of foot lesions, medical and surgical therapies of all patients admitted with a diagnosis of DF and CLI. All patients were followed-up for at least 1 year and/or total recovery. The primary endpoint was 1-year amputation-free survival (AFS), secondary endpoints were limb salvage and survival. Results: Between October 2014 and October 2017, 1024 patients with DF and CLI were admitted to the center. Eighty-four of them (8.2%) fulfilled the criteria for no-option CLI. At 1 year, AFS, limb salvage, and survival rates were 34%, 34%, and 83%, respectively. Lesions located proximal to the Lisfranc joint were associated with major amputation (HR 2.1 [1.2-3.6]). One-year survival of patients treated with minor procedures was significantly higher compared to patients treated with major amputation (96% vs 76%, log-rank p = 0.019). Major amputation was independently associated with mortality (HR 7.83 [1.02-59.89]). Conclusions: The application of dedicated and standardized strategies permitted limb salvage in one-third of patients with no-option CLI. Patients with stable lesions limited to the forefoot and without ischaemic pain had a greater probability to successfully receive conservative treatments. Limb salvage was associated with subsequent higher one-year survival.

Peripheral arterial disease: Scoping review of patient-centred outcomes

Peripheral arterial disease (PAD) impairs patients' quality of life (QOL), walking and ulcer healing, increasing patient pain, costs, and risks of amputation or mortality. A literature appraisal described PAD treatment capacity to improve validated patient-centred outcomes in controlled clinical studies. The PUBMED database was searched from 1 January 1970 to 21 June 2018, for original and derivative controlled clinical trial references addressing MeSH terms for 'ischemia' AND 'leg ulcer'. Non-ischemic ulcer treatment references were excluded. Frequencies of improved (P < .05) outcomes were reported. Eighty-eight studies on 4153 patients were summarized. Walking, pain or QOL improved mainly for interventions administered before PAD became severe. Amputation incidence, pain and ulcer healing were more frequently reported in those with severe PAD. Independent of PAD severity, patients experienced more likely improved walking, QOL, or pain reduction in response to structured walking interventions or those increasing calf muscle activity. Those with more severe PAD were more likely to report amputation reduction, mainly in response to invasive interventions. Those with PAD experienced more consistently improved patient-centred outcomes if they received multidisciplinary PAD management with supervised walking or calf muscle activity, with more likely amputation risk reduced for those with more severe PAD.

Randomized Placebo-/Sham-Controlled Trials of Spinal Cord Stimulation: A Systematic Review and Methodological Appraisal

OBJECTIVES

The recent availability of paraesthesia/sensation free spinal cord stimulation (SCS) modalities allow the design of clinical trials of SCS using placebo/sham controls and blinding of patients, clinicians, and researchers. The aims of this study were to: 1) systematically review the current evidence base of randomized controlled trials (RCTs) of SCS placebo/sham trials and 2) to undertake a methodological critique of their methods. Based on this critique, we developed a checklist for the design and reporting of future RCTs of SCS.

MATERIALS AND METHODS

Electronic data bases were searched from inception until January 2019 for RCTs of SCS using a placebo/sham control. RCTs with only an active comparator arm were excluded. The results are presented as a narrative synthesis.

RESULTS

Searches identified 12 eligible RCTs. SCS modalities included paraesthesia stimulation, subthreshold, burst, and high-frequency SCS and were mainly conducted in patients with failed back surgery syndrome, complex regional pain syndrome, and refractory angina. The quality and transparency of reporting of the methods of placebo stimulation, blinding of patients, clinicians, and researchers varied markedly across studies.

CONCLUSIONS

To date the methods of placebo/sham control and blinding in RCTs have been poorly reported, leading to concerns about the validity and replicability of the findings. Important aspects that need to be clearly reported in the design of placebo-/sham-controlled RCTs of SCS include the transparent reporting of stimulation programming parameters, patient position during perception threshold measurement, management of the patient handheld programmer, frequency of recharging, and assessment of the fidelity of blinding.

The Clinical Outcomes in Patients with Critical Limb Ischemia One Year after Spinal Cord Stimulation

BACKGROUND

The aim of this study was to evaluate the long-term outcomes of spinal cord stimulation in patients with critical limb ischemia and to test the hypothesis that the dynamics of clinical changes one year after therapy depend both on the clinical determinants associated with the underlying disease and on factors related to systemic atherosclerosis.

METHODS

This prospective cohort study included 56 patients with critical limb ischemia. All patients before and after spinal cord stimulation were examined in terms of the dynamics of their clinical changes using the Rutherford scale and transcutaneous oxygen tension (TcPO₂, mm Hg) in the affected foot. The active orthostatic test was used to assess the functional state of peripheral perfusion.

RESULTS

One year after spinal cord stimulation, 74% of patients showed positive clinical outcomes. No changes were observed in 9.3% of patients, whereas adverse clinical outcomes were revealed in 16.7% of cases. The TcPO₂ values were significantly reduced before spinal cord stimulation: 10.5 (6.4-16.0) mm Hg. The functional status of the peripheral microvasculature was also disturbed. One year after therapy, TcPO₂ significantly increased and the adaptive mechanisms of the microvasculature were improved in more than 70% of patients. Logistic regression analysis showed that the initially low TcPO₂ values (<10 mm Hg) with a lack of gain in TcPO₂ during the orthostatic test are associated with the negative clinical outcomes after spinal cord stimulation. The gain in TcPO₂ during the orthostatic test to >10 mm Hg is associated with the positive clinical outcomes after spinal cord stimulation. The age-adjusted Charlson Comorbidity Index >5 and duration of critical ischemic symptoms also had a negative effect on the clinical outcomes after spinal cord stimulation.

CONCLUSIONS

The positive clinical outcomes were revealed in most patients with critical limb ischemia one year after spinal cord stimulation. The low values of peripheral tissue metabolism with the disturbed functional status of the microvasculature are associated with the negative clinical outcome. The patients with baseline TcPO₂ <10 mm Hg can recover if they still have a sufficient microcirculatory reserve capacity. Duration of critical ischemic symptoms and high comorbidity burden with allowance for age are negative factors affecting the clinical outcome.

Spinal Cord Stimulation

Spinal cord stimulation (SCS) has been well established as a safe and effective treatment of pain derived from a wide variety of etiologies. Careful patient selection including a rigorous trial period and psychological evaluation are essential. When patients proceed to permanent implantation, various considerations should be made, such as the type of lead, type of anesthesia, and waveform patterns for SCS. This article discusses the common indications for SCS, patient selection criteria, and pertinent outcomes from randomized clinical trials related to common indications treated with SCS. Technical considerations, such as type of implant, anesthesia, and programming, are also discussed.

Spinal Cord Stimulation in Chronic Pain: A Review of the Evidence

This review looks at the evidence for the effectiveness of spinal cord stimulation in various chronic pain states. Spinal cord stimulation can only be effective when appropriate dorsal column fibres in the spinal cord are preserved and able to be stimulated. Spinal cord stimulation has been shown to have little to offer for patients with some diagnoses. Although 50 to 60% of patients with failed back surgery syndrome obtain significant pain relief with this technique, the strength of the evidence available is insufficient to clearly advocate its use in all patients with this condition. Though limited in quantity and quality, better evidence exists for its use in neuropathic pain, complex regional pain syndrome, angina pectoris and critical limb ischaemia. There is a lack of high quality evidence relating to spinal cord stimulation due to difficulties in conducting randomized controlled trials in this area. Serious methodological problems are encountered in blinding, recruitment and assessment in nearly all published trials of spinal cord stimulation. Suggestions regarding appropriate methodologies for trials which would produce better quality evidence are summarized.

Spinal Cord Stimulation 50 Years Later: Clinical Outcomes of Spinal Cord Stimulation Based on Randomized Clinical Trials-A Systematic Review

To assess the efficacy of spinal cord stimulation (SCS) for each indication, one must critically assess each specific clinical outcome to identify outcomes that benefit from SCS therapy. To date, a comprehensive review of clinically relevant outcome-specific evidence regarding SCS has not been published. We aimed to assess all randomized controlled trials from the world literature for the purpose of evaluating the clinical outcome-specific efficacy of SCS for the following outcomes: perceived pain relief or change pain score, quality of life, functional status, psychological impact, analgesic medication utilization, patient satisfaction, and health care cost and utilization. Interventions were SCS, without limitation to the type of controls or the type of SCS in the active arms. For each study analyzed, a quality assessment was performed using a validated scale that assesses reporting, external validity, bias, confounding, and power. Each outcome was assessed specific to its indication, and the primary measure of each abovementioned outcome was a summary of the level of evidence. Twenty-one randomized controlled trials were analyzed (7 for trunk and limb pain, inclusive of failed back surgery syndrome; 8 for refractory angina pectoris; 1 for cardiac X syndrome; 3 for critical limb ischemia; 2 for complex regional pain syndrome; and 2 for painful diabetic neuropathy). Evidence assessments for each outcome for each indication were depicted in tabular format. Outcome-specific evidence scores were established for each of the abovementioned indications, providing both physicians and patients with a summary of evidence to assist in choosing the optimal evidence-based intervention. The evidence presented herein has broad applicability as it encompasses a breadth of patient populations, variations of SCS therapy, and comparable controls that, together, reflect comprehensive clinical decision making.

Spinal Cord Stimulation for Acute Pain Following Surgery for Cervical Myelopathy: A Novel Treatment Strategy

BACKGROUND

Chronic pain syndromes caused by degenerative and postinfectious changes in the cervical spine continue to pose significant management challenges to neurosurgeons and pain practitioners. The identification of an individualized treatment plan, astute surgical technique, comprehensive and multimodal analgesia, and adequate rehabilitation processes do not necessarily result in diminished pain.

CASE SUMMARY

We present the case of a patient with chronic pain treated surgically for degenerative cervical myelopathy secondary to cervical spinal stenosis. Following this surgery, the patient experienced an intractable postoperative pain syndrome that had anatomical borders, and an intensity and character that were different from the background chronic pain from which he suffered. We successfully implanted a cervical spinal cord stimulation (SCS) lead in the period following his stenosis surgery, which had good therapeutic effect on the postoperative-onset pain. To the best of our knowledge, this is the first description of SCS having a strong positive effect on an acute exacerbation of neuropathic pain. At follow-up 12 months later, assessment of the patient's pain diary revealed a modal pain intensity of 3/10 on the numeric rating scale over the preceding 3 months. The Brief Pain Inventory (Short Form) scores at this time were 10/40 in the pain severity domain and 18/70 in the interference with function domain, demonstrating the long-term effectiveness of this SCS strategy.

CONCLUSION

While SCS has hitherto been untested as a therapy for acute-onset pain, this report demonstrates its utility as a salvage treatment in select cases of uncontrollable postoperative pain.

Alternate Intraspinal Targets for Spinal Cord Stimulation: A Systematic Review

BACKGROUND

Conventional dorsal column spinal cord stimulation (SCS) provides less than optimal pain relief for certain pain syndromes and anatomic pain distributions. Practitioners have sought to treat these challenging therapeutic areas with stimulation of alternate intraspinal targets.

OBJECTIVE

To identify and systematically review the evidence for the value neuromodulating specific neuronal targets within the spinal canal to achieve relief of chronic pain.

METHODS

A systematic literature search was conducted using PubMed for clinical trials published from 1966 to March 1, 2015 to identify neurostimulation studies that employed non-dorsal column intraspinal stimulation to achieve pain relief. Identified studies on such targeted intraspinal stimulation were reviewed and graded using Evidence Based Interventional Pain Medicine criteria.

RESULTS

We found a total of 13 articles that satisfied our search criteria on targeted, non-dorsal column intraspinal stimulation for pain. We identified five studies on neurostimulation of the cervicomedullary junction, six studies on neurostimulation of the dorsal root ganglion, two studies on the neurostimulation of the conus medullaris, unfortunately none was found on intraspinal nerve root stimulation.

LIMITATIONS

The limitations of this review include the relative paucity of well-designed prospective studies on targeted SCS.

CONCLUSIONS

Clinical use of intraspinal neurostimulation is expanding at a very fast pace. Intraspinal stimulation of non-dorsal column targets may well be the future of neurostimulation as it provides new clinically significant neuromodulation of specific therapeutic targets that are not well or not easily addressed with conventional dorsal column SCS. In addition, they may avoid undesired stimulation induced paraesthesia, particularly in non-painful areas of the body.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

[Spinal cord stimulation and failed back surgery syndrome. Clinical results with laminectomy electrodes]

INTRODUCTION

Spinal cord stimulation is a widely-accepted technique in the treatment of back pain resulting from failed back surgery. Classically, stimulation has been carried out with percutaneous electrodes implanted under local anaesthesia and sedation. However, the ease of migration and the difficulty of reproducing electrical paresthesias in large areas with such electrodes has led to increasing use of surgical plate leads, which have the disadvantage of the need for general anaesthesia and a laminectomy for implantation.

OBJECTIVES

Our objective was to report the clinical results, technical details, advantages and benefits of laminectomy lead placement under epidural anaesthesia in failed back surgery syndrome cases.

MATERIAL AND METHODS

Spinal cord stimulation was performed in a total of 119 patients (52 men and 67 women), aged between 31 and 73 years (average, 47.3). Epidural anaesthesia was induced with ropivacaine. In all cases we inserted the octapolar or 16-polar lead in the epidural space through a small laminectomy. The final position of the leads was the vertebral level that provided coverage of the patient's pain. The electrodes were connected at dual-channel or rechargeable pulse generators.

RESULTS

After a mean follow-up of 4.7 years, the results in terms of improvement of the previous painful situation was satisfactory, with an analgesia level of 58% of axial pain and 60% of radicular pain in more than 70% of cases. None of the patients said that the surgery stage was painful or unpleasant. No serious complications were included in the group, but in 6 cases the system had to be explanted because of ineffectiveness or intolerance of long-term neurostimulation.

CONCLUSIONS

This study, with a significant number of patients, used epidural anaesthesia for spinal cord stimulation of lead implants by laminectomy in failed back surgery syndromes. The technique seems to be safe and effective.

Spinal cord stimulation: Background and clinical application

Background Spinal cord stimulation (SCS) is a surgical treatment for chronic neuropathic pain refractory to conventional treatment. SCS treatment consists of one or more leads implanted in the epidural space of the spinal canal, connected to an implantable pulse generator (IPG). Each lead carries a number of contacts capable of delivering a weak electrical current to the spinal cord, evoking a feeling of peripheral paresthesia. With correct indication and if implanted by an experienced implanter, success rates generally are in the range of about 50-75%. Common indications include complex regional pain syndrome (CRPS I), angina pectoris, and radicular pain after failed back surgery syndrome, and the treatment is also used to treat stump pain after amputation, and pain due to peripheral nerve injury, peripheral vascular disease, and diabetic neuropathy. Recommended contraindications for the treatment include pregnancy, coagulopathy, severe addiction to psychoactive substances, and lack of ability to cooperate (e.g. due to active psychosis or cognitive impairment). Most common complications to the treatment include lead migration, lead breakage, infection, pain over the implant, and dural puncture. Despite extensive research in the area, the mechanisms of action are still only partially understood. Methods In this topical review the historical background behind the treatment is described and the current theories on the mechanism of action are presented. The implantation procedure is described in detail and illustrated with a series of intraoperative pictures. Finally, indications for SCS are discussed along with some of the controversies surrounding the therapy. Implications The reader is presented with a broad overview of spinal cord stimulation, including the historical and theoretical background, practical implantation technique, and clinical application.

Peripheral arterial disease

Peripheral arterial disease (PAD) is an atherosclerotic-driven condition that remains underdiagnosed and undertreated. In diabetic patients, PAD begins early, progresses rapidly, and is frequently asymptomatic, making it difficult to diagnose. Strict management of the metabolic instigators and use of screening techniques for PAD in diabetes can facilitate early diagnosis and reduce progression. Exercise is an equally effective treatment option in improving walking distance. Early revascularization must be offered early in suitable patients. Surgical bypass and endovascular revascularization are complementary and the choice of intervention should be applied appropriately by a multidisciplinary vascular team on a selective, patient-specific basis.

Predictors of improved quality of life and claudication in patients undergoing spinal cord stimulation for critical lower limb ischemia

BACKGROUND

The aim of this study was to determine predictors of improved quality of life and claudication in patients undergoing spinal cord stimulation (SCS) for critical lower limb ischemia.

METHODS

We retrospectively analyzed 101 consecutive patients with few meter claudication and nonhealing ulcer who underwent definitive SCS. These patients were selected among 274 SCS patients treated at our center from 1995 to 2012. All presented with non-reconstructable critical leg ischemia (NR-CLI) and underwent supervised exercise therapy, best medical care and regular ulcers standard or advanced medications for at least 1 month before SCS implantation. We measured self-perceived quality of life using the SF-36 questionnaire. Patients with an improved walking distance of at least 30 meters after SCS had significant improvement on SF-36 questionnaire scores. We considered 30 meters as the cut-off for clinically significant improvement in pain-free walking distance, and we defined this value as functional success. Logistic regression was applied to assess baseline and other patient variables as possible predictors of functional success.

RESULTS

Neither perioperative mortality nor significant complications were found. At a median follow-up of 69 months (range 1-202 months), mortality, major amputation, and minor amputation were 8.9%, 5.9%, and 6.9%, respectively. Functional clinical success was reported in 25.7% of cases. Independent predictors of functional success at univariate analysis included delay between the onset of the ulcer and SCS (P < 0.001) and the pain-free walking distance before SCS (P < 0.002). The only predictive factor of functional success at multivariate analysis was the delay between the onset of ulcer and SCS (median delay in patients with and without functional success was 3 and 15 months, respectively). In particular, comparable to pain-free walking distance before SCS, the success rate decreased by 40% for each month elapsed from onset of ulcer to SCS.

CONCLUSIONS

In our series of patients who underwent SCS, reduced delay between the onset of ulcer and SCS was associated with improved quality of life and walking distance. Larger series are required to confirm these data and to assess clinical implications.

Spinal magnetic resonance imaging with reduced specific absorption rate in patients harbouring a spinal cord stimulation device - A single-centre prospective study analysing safety, tolerability and image quality

BACKGROUND

Spinal cord stimulation (SCS) is an accepted treatment in patients with failed back surgery (FBS), complex regional pain syndrome (CRPS) and persistent radicular pain following surgery. In order to avoid patient hazards or device malfunction manufacturers advise to abstain from magnetic resonance imaging (MRI) in patients with implanted electrodes or pulse generators.

METHODS

In a prospective study, 13 patients harbouring an implanted Medtronic Spinal Cord Stimulation (SCS) device underwent MRI (1.5 T) of the lumbar (n=13), the cervical (n=2) or the thoracic spine (n=1) following the development of new spinal symptoms. An adapted MRI protocol was used limiting the transmitted energy and specific absorption rate. Tolerability and safety were assessed by means of a standardized patient evaluation form documenting pain on a visual analogue scale (0-10), neurologic deficit, and discomfort during the scan. In addition, overall satisfaction with the examination procedure was rated on a Likert scale (1-5). Image quality was rated independently and blinded to the presence of a SCS device by the radiologist and the surgeon as equivalent, superior or inferior compared to the standard spine MRI examination.

RESULTS

None of the 13 patients investigated by the modified spinal MRI protocol experienced new neurological deficits, worsening of symptoms or a defect/malfunction of the implant device. Three patients (23.1 %) reported transient warm sensation in the location of the electrode and in one case intermittent slight tingling in the lower extremities. Overall satisfaction with the examination was 1.13 ± 0.34 according to Likert scale (1-5). The image quality was rated - not statistically significant - slightly inferior to standard lumbar spine imaging (0.82 ± 0.54) with a kappa value of 0.68 between the two investigators. MRI examinations detected relevant and new lesions in 9 (69.2 %) patients which affected treatment in 8 (61.5 %) individuals.

CONCLUSION

Using a protocol with a reduced specific energy absorption rate, spinal MRI examinations in patients with SCS can be considered safe. The current view that neurostimulators are a general contraindication to MR examinations has to be reconsidered in patients with new or progressive spinal symptoms.

Cost-effectiveness of spinal cord stimulation therapy in management of chronic pain

OBJECTIVE

To evaluate the cost-effectiveness of spinal cord stimulation (SCS) and conventional medical management (CMM) compared with CMM alone for patients with failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), peripheral arterial disease (PAD), and refractory angina pectoris (RAP).

DESIGN

Markov models were developed to evaluate the cost-effectiveness of SCS vs CMM alone from the perspective of a Canadian provincial Ministry of Health. Each model followed costs and outcomes in 6-month cycles. Health effects were expressed as quality-adjusted life years (QALYs). Costs were gathered from public sources and expressed in 2012 Canadian dollars (CAN$). Costs and effects were calculated over a 20-year time horizon and discounted at 3.5% annually, as suggested by the National Institute of Clinical Excellence. Cost-effectiveness was identified by deterministic and probabilistic sensitivity analysis (50,000 Monte-Carlo iterations). Outcome measures were: cost, QALY, incremental net monetary benefit (INMB), incremental cost-effectiveness ratio (ICER), expected value of perfect information (EVPI), and strategy selection frequency.

RESULTS

The ICER for SCS was: CAN$ 9,293 (FBSS), CAN$ 11,216 (CRPS), CAN$ 9,319 (PAD), CAN$ 9,984 (RAP) per QALY gained, respectively. SCS provided the optimal economic path. The probability of SCS being cost-effective compared with CMM was 75-95% depending on pathology. SCS generates a positive INMB for treatment of pain syndromes. Sensitivity analyses demonstrated that results were robust to plausible variations in model costs and effectiveness inputs. Per-patient EVPI was low, indicating that gathering additional information for model parameters would not significantly impact results.

CONCLUSION

SCS with CMM is cost-effective compared with CMM alone in the management of FBSS, CRPS, PAD, and RAP.

Spinal cord stimulation for non-reconstructable chronic critical leg ischaemia

BACKGROUND

Patients suffering from inoperable chronic critical leg ischaemia (NR-CCLI) face amputation of the leg. Spinal cord stimulation (SCS) has been proposed as a helpful treatment in addition to standard conservative treatment.

OBJECTIVES

To find evidence for an improvement on limb salvage, pain relief, and the clinical situation using SCS compared to conservative treatment alone.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched January 2013) and CENTRAL (2012, Issue 12).

SELECTION CRITERIA

Controlled studies comparing the addition of SCS with any form of conservative treatment to conservative treatment alone in patients with NR-CCLI.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed the quality of the studies and extracted data.

MAIN RESULTS

Six studies comprising nearly 450 patients were included. In general the quality of the studies was good. No study was blinded due to the type of intervention.Limb salvage after 12 months was significantly higher in the SCS group (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.56 to 0.90; risk difference (RD) -0.11, 95% CI -0.20 to -0.02). Significant pain relief occurred in both treatment groups, but was more prominent in the SCS group where the patients required significantly less analgesics. In the SCS group, significantly more patients reached Fontaine stage II than in the conservative group (RR 4.9, 95% CI 2.0 to 11.9; RD 0.33, 95% CI 0.19 to 0.47). Overall, no significantly different effect on ulcer healing was observed with the two treatments.Complications of SCS treatment consisted of implantation problems (9%, 95% CI 4 to 15%) and changes in stimulation requiring re-intervention (15%, 95% CI 10 to 20%). Infections of the lead or pulse generator pocket occurred less frequently (3%, 95% CI 0 to 6%). Overall risk of complications with additional SCS treatment was 17% (95% CI 12 to 22%), indicating a number needed to harm of 6 (95% CI 5 to 8).Average overall costs (one study) at two years were EUR 36,500 (SCS group) and EUR 28,600 (conservative group). The difference (EUR 7900) was significant (P < 0.009).

AUTHORS' CONCLUSIONS

There is evidence to favour SCS over standard conservative treatment alone to improve limb salvage and clinical situations in patients with NR-CCLI. The benefits of SCS must be considered against the possible harm of relatively mild complications and the costs.

An innovative case report detailing the successful treatment of post-thoracotomy syndrome with peripheral nerve field stimulation

INTRODUCTION

The detrimental effects of post-thoracotomy pain syndrome is experienced worldwide; however, an effective treatment regimen remains elusive.

METHODS

We report a case of post-thoracotomy pain syndrome effectively treated with peripheral nerve field stimulation (PNfS).

RESULTS

In the presented case, the patient underwent permanent placement of the PSfS device after a successful trial period. Upon follow-up the patient has reported even better coverage over her painful areas and admits to 80% and higher reductions in her painful symptoms.

CONCLUSION

Although the data are limited, in the aforesaid case report, post-thoracotomy syndrome was effectively treated with the use of PNfS. This resulted in a significant pain perception reduction, increased quality of life and mobility, as well as decreased usage of oral pain medications. This adds to the accumulating case report and case series data that suggest PNfS is showing great promise as a pain reduction modality. Further, it is minimally invasive, can be trialled prior to implantation, and is reversible. Large prospective studies will be required in the future to further evaluate its efficacy before it can be widely accepted and adopted.

Spinal cord stimulation in pain management: a review

Spinal cord stimulation has become a widely used and efficient alternative for the management of refractory chronic pain that is unresponsive to conservative therapies. Technological improvements have been considerable and the current neuromodulation devices are both extremely sophisticated and reliable in obtaining good results for various clinical situations of chronic pain, such as failed back surgery syndrome, complex regional pain syndrome, ischemic and coronary artery disease. This technique is likely to possess a savings in costs compared with alternative therapy strategies despite its high initial cost. Spinal cord stimulation continues to be a valuable tool in the treatment of chronic disabling pain.

Technological innovation in spinal cord stimulation: use of a newly developed delivery device for introduction of spinal cord stimulation leads

OBJECTIVE

The use of multiple cylindrical leads and multicolumn and single column paddle leads in spinal cord stimulation offers many advantages over the use of a single cylindrical lead. Despite these advantages, placement of multiple cylindrical leads or a paddle lead requires a more invasive surgical procedure. Thus, the ideal situation for lead delivery would be percutaneous insertion of a paddle lead or multiple cylindrical leads. This study evaluated the feasibility and safety of percutaneous delivery of S-Series paddle leads using a new delivery device called the Epiducer lead delivery system (all St. Jude Medical Neuromodulation Division, Plano, TX, USA).

MATERIALS AND METHODS

This uncontrolled, open-label, prospective, two-center study approved by the AZ St. Lucas (Ghent) Ethics Committee evaluated procedural aspects of implantation of an S-Series paddle lead using the Epiducer lead delivery system and any adverse events relating to the device. Efficacy data during the patent's 30-day trial also were collected.

RESULTS

  Data from 34 patients were collected from two investigational sites. There were no adverse events related to the Epiducer lead delivery system. The device was inserted at an angle of either 20°-30° or 30°-40° and was entered into the epidural space at T12/L1 in most patients. The S-Series paddle lead was advanced four vertebral segments in more than 50% of patients. The average (±standard deviation [SD]) time it took to place the Epiducer lead delivery system was 8.7 (±5.0) min. The average (+SD) patient-reported pain relief was 78.8% (+24.1%).

CONCLUSIONS

This study suggests the safe use of the Epiducer lead delivery system for percutaneous implantation and advancement of the S-Series paddle lead in 34 patients.

The role of amputation as an outcome measure in cellular therapy for critical limb ischemia: implications for clinical trial design

BACKGROUND

Autologous bone marrow-derived stem cells have been ascribed an important therapeutic role in No-Option Critical limb Ischemia (NO-CLI). One primary endpoint for evaluating NO-CLI therapy is major amputation (AMP), which is usually combined with mortality for AMP-free survival (AFS). Only a trial which is double blinded can eliminate physician and patient bias as to the timing and reason for AMP. We examined factors influencing AMP in a prospective double-blinded pilot RCT (2:1 therapy to control) of 48 patients treated with site of service obtained bone marrow cells (BMAC) as well as a systematic review of the literature.

METHODS

Cells were injected intramuscularly in the CLI limbs as either BMAC or placebo (peripheral blood). Six month AMP rates were compared between the two arms. Both patient and treating team were blinded of the assignment in follow-up examinations. A search of the literature identified 9 NO-CLI trials, the control arms of which were used to determine 6 month AMP rates and the influence of tissue loss.

RESULTS

Fifteen amputations occurred during the 6 month period, 86.7% of these during the first 4 months. One amputation occurred in a Rutherford 4 patient. The difference in amputation rate between patients with rest pain (5.6%) and those with tissue loss (46.7%), irrespective of treatment group, was significant (p = 0.0029). In patients with tissue loss, treatment with BMAC demonstrated a lower amputation rate than placebo (39.1% vs. 71.4%, p = 0.1337). The Kaplan-Meier time to amputation was longer in the BMAC group than in the placebo group (p = 0.067). Projecting these results to a pivotal trial, a bootstrap simulation model showed significant difference in AFS between BMAC and placebo with a power of 95% for a sample size of 210 patients. Meta-analysis of the literature confirmed a difference in amputation rate between patients with tissue loss and rest pain.

CONCLUSIONS

BMAC shows promise in improving AMP-free survival if the trends in this pilot study are validated in a larger pivotal trial. The difference in amp rate between Rutherford 4 & 5 patients suggests that these patients should be stratified in future RCTs.

The Clinical Application of Ozonetherapy

The reader may be eager to examine in which diseases ozonetherapy can be proficiently used and she/he will be amazed by the versatility of this complementary approach (Table 9 1). The fact that the medical applications are numerous exposes the ozonetherapist to medical derision because superficial observers or sarcastic sceptics consider ozonetherapy as the modern panacea. This seems so because ozone, like oxygen, is a molecule able to act simultaneously on several blood components with different functions but, as we shall discuss, ozonetherapy is not a panacea. The ozone messengers ROS and LOPs can act either locally or systemically in practically all cells of an organism. In contrast to the dogma that “ozone is always toxic”, three decades of clinical experience, although mostly acquired in private clinics in millions of patients, have shown that ozone can act as a disinfectant, an oxygen donor, an immunomodulator, a paradoxical inducer of antioxidant enzymes, a metabolic enhancer, an inducer of endothelial nitric oxide synthase and possibly an activator of stem cells with consequent neovascularization and tissue reconstruction.

A prognostic model for amputation in critical lower limb ischemia

In a (negative) multicenter randomized trial on management for inoperable critical lower limb ischemia, comparing spinal cord stimulation and best medical treatment, a number of pre-defined factors were analyzed for prognostic value. We included a radiological arterial disease score, modified from the SVS/ISCVS runoff score. The purpose of this analysis was to evaluate clinical factors and commonly used circulatory measurements for prognostic modeling in patients with critical lower limb ischemia. We determined the incidence of amputation and its relation to various pre-defined risk factors. A total of 120 patients with critical limb ischemia were included in the study. The integrity of circulation in the affected limb was evaluated on five levels: suprainguinal, infrainguinal, popliteal, infrapopliteal and pedal. A total radiological arterial disease score was calculated from 1 (full integrity of circulation) to 20 (maximally compromised state). We used Cox regression analysis to quantify prognostic effects and differential treatment (predictive) effects. Major amputation occurred in 33% of the patients at 6 months and in 51% at 2 years. The presence of ischemic skin lesions and the radiological arterial disease score were independent prognostic factors for amputation. Patients with ulcerations or gangrene had a higher amputation risk (hazard ratio 2.38, p = 0.018 and 2.30, p = 0.036 respectively) as well as patients with a higher radiological arterial disease score (hazard ratio 1.17 per increment, p = 0.003). We did not observe significant interactions between prognostic factors and the effect of spinal cord stimulation. In conclusion, in patients with critical lower limb ischemia, the presence of ischemic skin lesions and the described radiological arterial disease score can be used to estimate amputation risk.

Therapeutic angiogenesis in the management of critical limb ischemia: current concepts and review

Critical limb ischemia (CLI) represents the most severe form of peripheral arterial disease. Manifestations of CLI include rest pain, ischemic ulcers, and/or gangrene. The presence of CLI frequently leads to amputation, and furthermore, patients with CLI are at an increased risk of cardiovascular events including death. Treatment options for CLI when revascularization is not possible are extremely limited. Therapeutic angiogenesis is a promising new tool in the management of CLI. There is a growing body of evidence demonstrating the safety and efficacy of therapeutic angiogenesis with gene and cell therapy. Many factors must be considered in formulating clinically efficacious gene and/or cell therapies. The dosing regimen, route of delivery, and choice of growth factor or cell population must be decided. Although the optimal regimen of therapeutic angiogenesis has yet to be identified, building on the knowledge gained from the early pioneering studies may help to identify the best combination.