Complex regional pain syndrome: the case for spinal cord stimulation (a brief review)

Complex regional pain syndrome is a disabling disorder with an unknown mechanism which is extremely resistant to conventional pharmaceutical and therapeutic therapies. In this paper we present the underlying theories of this disorder. We present spinal cord stimulation as an alternative to conventional interventions in the management of this disabling condition spinal cord stimulation significantly improves pain, reduces narcotic intake and improves activity levels and overall quality of life. There is now a significant body of evidence to support the utilization of spinal cord stimulation in the management of complex regional pain syndrome.     

Spinal epidural stimulation for central pain caused by spinal cord lesion]

Epidural spinal cord stimulation was carried out in 4 patients with denervation caused by spinal cord lesion, and we reviewed previously reported cases. Initial result showed at 1 week in 100% of our cases, but about 1/3 of the cases, even those with the same denervation caused by spinal cord lesion, had no pain relief at this stage in previously reported cases. In our cases, excellent pain relief was gained temporarily, even though the painful area and the spinal cord lesion were separated somatotopically in 2 cases (case 3, 4). Temporary success bore no relationship to quality and duration of pain. In all cases except case 1, a rapidly decreasing effectiveness was noted, and finally no pain relief was gained at all after 4, 3 and 5 months, respectively. In case 1 there was persistent pain relief estimated at 70-80% after 19 months, only when the spinal cord was stimulated. Epidural stimulation also produced sensations in the painful area. Spinal cord stimulation would suppress at least the dorsal horn neurons which were destroyed by various kinds of diseases. A decline in effectiveness with time would occur due to essential causes of the deafferentation pain, such as anatomical and regeneration factors.     

Spinal cord stimulation does not change peripheral skin blood flow in patients with neuropathic pain

BACKGROUND AND OBJECTIVE: Spinal cord stimulation has been used successfully for many years in the management of neuropathic pain. Nociceptive pathways are closely integrated into many autonomic reflexes. The aim was to test the hypothesis that pain relief caused by spinal cord stimulation is related to changes in peripheral skin blood flow. METHODS: Twelve patients with spinal cord stimulators implanted as a treatment for neuropathic pain were entered into the study. Laser Doppler perfusion scanning was used as a direct method for selective measurement of changes in skin (peripheral) blood flow. Measurements were taken before and after the onset of spinal cord stimulation over the site of its sensory projection. The degree of pain relief due to spinal cord stimulation and the skin temperature of each patient were also recorded. RESULTS: Apart from one patient, spinal cord stimulation did not change skin blood flow in a statistically significant manner. CONCLUSIONS: Pain relief due to spinal cord stimulation is not related to changes of skin blood flow.     

The use of spinal cord stimulation for severe limb-threatening ischemia: a preliminary report

Spinal cord stimulation has been shown to control ischemic pain. We have applied spinal cord stimulation to nine patients with rest pain, non-healing ulceration, or digital gangrene to evaluate its effect on limb salvage. The patients had a mean age of 69 years. Six were diabetic, and all had previous major complications of their atherosclerotic disease. Stimulation was obtained by placing an electrode on the spinal cord under local anesthesia. Seven patients experienced marked reduction in their ischemic pain immediately after stimulation. These patients also had improved healing of ulcers documented by direct measurement. No significant change in ankle/brachial Doppler indices could be measured in any patient. One patient became suddenly worse and required amputation after one year of good pain relief and ulcer improvement. Two patients were not helped and went on to amputation within one month of stimulation. We conclude from these preliminary data that spinal cord stimulation effectively relieves ischemic pain and is associated with improved ulcer healing.     

Long-term outcome of patients treated with spinal cord stimulation for therapeutically refractory failed back surgery syndrome: a retrospective study

Background and purpose

Long-term efficiency (> 5 years) of spinal cord stimulation for failed back surgery syndrome is poorly described in literature. The aims of our study were to evaluate the long-term efficiency and the quality of life of our series of patients with spinal cord stimulation for failed back surgery syndrome.

Methods

The data of 55 patients implanted successively in our institution between 1995 and 2005 for failed back surgery syndrome were collected retrospectively. We contacted them for a telephone survey focused on efficiency, quality of life and treatment satisfaction.

Results

An internal pulse generator was placed in 42 patients. Thirty-two of them were contacted to answer our survey with a mean follow-up of 8.3 years. Seventy-five percent of our population reported a pain decrease of greater or equal to 50%. The efficiency of percutaneous leads was reported as 50% for the quadripolars and 83% for the octopolars. The surgical leads evaluations were positive in 70% for 4 × 1 as well as for 4 × 2 leads. We observed a default of low back pain relief in 84% of patients with an incomplete pain relief (59%). The ability to sit, get out of the bed, and climb stairs increased in 75%. The walk was better in 82%. Decrease in drug consumption of greater or equal to 50% was observed in 66%.

Conclusions

Our retrospective study demonstrates a satisfaction of 75% of the patients after 8.3-years follow-up. Spinal cord stimulation is an effective treatment for refractory failed back surgery syndrome.     

Decreased insulin requirements with spinal cord stimulation in a patient with diabetes

We describe a case of type-2 diabetes mellitus with significant improvement in blood glucose control and significant decrease in insulin requirements after initiation of spinal cord stimulation. We believe that spinal cord stimulation may provide additional beneficial effects in patients with chronic pain and diabetes. IMPLICATIONS: Spinal cord stimulation when used for control of chronic pain in diabetics may provide additional benefits of improving glycemic control and insulin requirements.     

Appetite suppression and weight loss incidental to spinal cord stimulation for pain relief

Spinal cord stimulation (SCS) uses electrical stimulation of the dorsal columns of the spinal cord to prevent the perception of intractable neuropathic pain signals, but its mechanisms and consequences of use are poorly understood. Two overweight female patients who were implanted with SCS systems (Precision™; Advanced Bionics/Boston Scientific, Valencia, CA) reported better than 50% relief of their chronic back and leg pain. Unexpectedly, SCS stimulation was also associated with a tingling sensation in the viscera and a reduction in appetite. Both patients were thus able to reduce food intake at mealtimes and had lost about 9 kg in the first 4 months of SCS use, despite denying changes in exercise habits. The mechanism by which SCS can reduce the desire for food is unknown, but this and similar neuromodulation techniques may hold promise for weight loss in patients who fail other treatments or are not healthy enough for surgery. All data were collected in medical practice. Dr. Foster is an employee of Advanced Bionics/Boston Scientific.     

Failed back surgery syndrome: 5-year follow-up after spinal cord stimulator implantation.

Spinal cord stimulation, in use for more than 20 years, has evolved into an easily implemented technique, with percutaneous methods for electrode placement. We have reviewed our experience with this technique in treating "failed back surgery syndrome," and have assessed patient and treatment characteristics as predictors of long-term outcome. A series of 50 patients with failed back surgery syndrome (averaging 3.1 previous operations), who underwent spinal cord stimulator implantation, was interviewed by impartial third parties, at mean follow-up intervals of 2.2 years and 5.0 years. Successful outcome (at least 50% sustained relief of pain and patient satisfaction with the result) was recorded in 53% of patients at 2.2 years and in 47% of patients at 5.0 years postoperatively. Ten of 40 patients who were disabled preoperatively returned to work. Improvements in activities of daily living were recorded in most patients for most activities; loss of function was rare. Most patients reduced or eliminated analgesic intake. Statistical analysis (including univariate and multivariate logistic regression) of patient characteristics as prognostic factors showed significant advantages for female patients and for those with programmable multi-contact implanted devices. These results, in patients with postsurgical lumbar arachnoid and epidural fibrosis and without surgically remediable lesions, compare favorably with the results in two separate series of patients with failed back surgery syndrome, in whom 1) surgical lesions were diagnosed and repeated operation performed; and 2) monoradicular pain syndromes were diagnosed and dorsal root ganglionectomies performed at our institution. This suggests the need for further assessment of selection criteria, critical analysis of treatment outcome, and prospective study of spinal cord stimulation and alternative approaches to failed back surgery syndrome.     

Neurosurgical techniques in the management of chronic pain

Neurosurgical treatment for pain can be classified into three parts: treatment of the cause; neuromodulation using electrical stimulation or drug delivery systems; and neuro-ablative techniques. Treatment of the cause is exemplified by microvascular decompression for trigeminal neuralgia, arguably the treatment of choice for this condition. Lumbar microdiscectomy for sciatica can also be viewed in this light. Neuromodulation is a growing field. The most common technique is spinal cord stimulation and a growing body of evidence supports its use (e.g. for treatment of persistent pain following spinal surgery and complex regional pain syndrome). Rarer and more specialist techniques of stimulation are motor cortex and deep-brain stimulation. Intrathecal drug delivery systems are increasingly used, and may have increasing application in pain associated with malignancy. Neuro-ablative techniques are used less frequently, but find a place in restricted situations such as cordotomy for focal pain of malignancy and the DREZ lesion following spinal cord avulsion injury. All of these treatments are now delivered in a multidisciplinary context, with availability of other adjunctive treatments (be they comprehensive medical management) and the use of cognitive techniques – pain management programmes.     

PM01SPINAL CORD STIMULATION FOR CHRONIC REFRACTORY ANGINA

Spinal cord stimulation (SCS) involves the use of an epidurally placed, multiple electrode lead. Electrical stimulation between electrodes produces stimulation of the posterior spinal cord and can provide excellent pain relief and increased blood flow in a number of chronic limb pain conditions. Its efficacy has more recently been demonstrated in angina. Chronic stable angina pectoris is a major cause of disability and suffering. The aims of treatment are to prevent MI and death (increase the quantity of life) and reduce the symptoms (improve the quality of life). In the non‐acute condition, practitioners often struggle to manage angina because of a lack of understanding of modern concepts of pain. There is a widely held misconception that only revascularisation improves prognosis in chronic refractory angina‐ the term used to describe patients with stable angina that is treatment refractory. Over the last decade two pain services in New Zealand have been approached by cardiologists to provide spinal cord stimulation for such patients. This has been an intriguing experience! We have demonstrated that the placement of such leads in the lower cervical cord region provides excellent relief of angina. The technology is expensive (akin to the overall cost of CAVG surgery). We have demonstrated cost recoupment, by decreased hospitalisation, at approximately16 months post procedure. Sadly, this therapy has not been embraced. Possible reasons for this will be discussed. The concept of electrically modifying the neuronal signals versus re‐plumbing the blockage appears to be an anathema to cardiologists.     

10 kHz spinal cord stimulation for the treatment of non-surgical refractory back pain: subanalysis of pooled data from two prospective studies

Spinal cord stimulation at 10 kHz is a promising therapy for non-surgical refractory back pain; however, published data are currently limited. We present a subanalysis of prospectively collected clinical outcome data for non-surgical refractory back pain patients treated with 10 kHz spinal cord stimulation, from the independent cohorts of two previous studies (SENZA-RCT and SENZA-EU). Clinical outcomes were evaluated at pre-implantation (baseline), 3 months, 6 months and 12 months following 10 kHz spinal cord stimulator implantation. These included: pain relief; responder rate (≥ 50% pain relief from baseline); remission rate (VAS ≤ 3.0 cm); disability (Oswestry Disability Index(ODI)); and opioid use. At 3 months, average back pain decreased by 70% in the combined cohort (60% in the SENZA-RCT and 78% in the SENZA-EU cohorts). This was sustained at 12 months, with a 73% back pain responder rate and 68% remission rate in the combined cohort. Leg pain relief results were generally comparable to those for back pain relief. At 12 months, the combined cohort had an average decrease in ODI scores of 15.7% points from baseline and opioid use more than halved. In conclusion, 10 kHz spinal cord stimulation reduced pain, disability and opioid consumption in non-surgical refractory back pain subjects. Application of this therapy may improve the care of non-surgical refractory back pain patients and reduce their opioid consumption.     

Comparison of the Interference Effects on Somatosensory Evoked Potential from Tonic,Burst, and High-dose Spinal Cord Stimulations

Spinal cord stimulations have been used widely to treat intractable neuropathic pain. The conventional spinal cord stimulation paradigm, the “tonic” type, suppresses excessive activation of wide dynamic range neurons in the dorsal horn via the collateral branch from the dorsal column. Therefore, preserved dorsal column function is an important prerequisite for tonic spinal cord stimulations. A tonic spinal cord stimulation requires eliciting paresthesia in the painful area due to stimulation of the dorsal column and dorsal root. Recent spinal cord stimulation paradigms, including burst and high-dose, are set below the paresthesia threshold and are proposed to have different pain reduction mechanisms. We conducted an interference study of these different stimulation paradigms on the somatosensory evoked potential (SEP) to investigate differences in the sites of action between tonic and new spinal cord stimulations. We recorded posterior tibial nerve-stimulated SEP in seven patients with neuropathic pain during tonic, burst, and high-dose stimulations. The total electrical energy delivered was calculated during SEP-spinal cord stimulation interference studies. High-dose stimulations could not reduce the SEP amplitude despite higher energy delivery than tonic stimulation. Burst stimulation with an energy similar to the tonic stimulation could not reduce SEP amplitude as tonic stimulation. The study results suggested different sites of action and effects on the spinal cord between the conventional tonic and burst or high-dose spinal cord stimulations.     

Clinical and objective data on spinal cord stimulation for the treatment of severe Raynaud's phenomenon.

Ischemic vascular disease of the upper extremity represents a difficult therapeutic problem wherein medical treatment often fails. Epidural spinal cord stimulation has been shown to be an effective alternative in severe peripheral arterial disease. Although this method has been used for nearly two decades only limited experience exists in Raynaud's phenomenon of the upper limbs. In addition objective parameters to prove therapeutic success are not well defined. Herein we describe a patient with severe primary Raynaud's phenomenon over several years who had significant pain relief and complete healing of ischemic digital ulcerations after spinal cord stimulation. Pain level was evaluated using a visual rating scale before and after surgery. Microcirculatory parameters were assessed before and after spinal cord stimulation by capillary microscopy and laser Doppler anemometry. Significant improvement of red blood cell velocity, capillary density, and capillary permeability was demonstrated. At follow-up 18 months after surgery the patient had no complaints and all ulcerations of her fingertips had healed. Spinal cord stimulation appears to be an effective treatment in severe cases of Raynaud's phenomenon and we recommend its use in the case of failed medical therapy. Pain rating and capillary microscopy enable one to assess and visualize the effects of spinal cord stimulation.     

Spinal cord stimulation

Spinal cord stimulation (SCS) is a neuromodulation technique using electricity, proposed for the first time by Shealy in 1967, as an alternative to neuroablation. Technological improvements in the last 20 years (percutaneous electrodes, single and dual leads, octopolar electrodes, high energy internal pulse generators) have allowed to obtain good results with SCS in various clinical situations of chronic pain. The main clinical indications to SCS are: vascular pain--refractory angina and peripheral vascular diseases (PVD); rachidian pain--failed back surgery syndrome (FBSS), degenerative low back leg pain (LBLP), nerve root lesions, incomplete spine lesions, spinal stenosis; neuropathic pain; chronic regional pain syndrome (CRPS) type 1 and type 2; perineal pain and urological diseases (urge-incontinence, interstitial cystitis). There are important differences between Europe and USA in the SCS use in various indications, especially about PVD. Really, in Europe this technique has been widely used and, finally, there are prospective studies establishing the utility of SCS in: limb survival; pain control; regression to Fontaine stage II; improvement of free interval of claudication. All of this is going to change the attitude towards SCS in USA, where the amputation incidence for critical ischaemia is considerably higher than in Europe. An indication to SCS not very mentioned in literature and that seems to have good results is LBLP due to acquired or mixed (constitutional-acquired) spinal stenosis. In this situation SCS seems to improve notably pain control and quality of life index of patients.     

Non-opioid pharmacologic treatment of chronic spinal cord injury-related pain

Purpose: Spinal cord injury-related pain is often a severe debilitating condition that adversely affects the patient’s physical health, psychological wellbeing and quality of life. Opioid medications have historically been prescribed to this population with great frequency. As opioid abuse disorder becomes an ever-worsening public health issue, more attention must be placed upon non-opioid options. This paper reviews non-opioid medications to be considered when treating spinal cord injury-related pain. The pertinent literature is reviewed, and the advantages and pitfalls of various medication options are discussed in the complicated context of the individual with a spinal cord injury.Methods: Peer-reviewed journal articles and medication package insert data are reviewed.Results:. The non-opioid medications with the greatest evidence for efficacy in the treatment of chronic spinal cord injury-related pain are drawn from the antiepileptic drug and antidepressant categories though the specific selection must be nuanced to the particular individual patient. More research is required to understand the role of calcitonin, lithium, and marijuana in treating spinal cord injury-related pain.Conclusions: The complex clinical situation of each individual patient must be weighed against the risks and benefits of each medication, as reviewed in this paper, to determine the ideal treatment strategy for chronic spinal cord injury-related pain.     

False negative in spinal cord monitoring using spinal cord-evoked potentials following spinal cord stimulation during surgery for thoracic OPLL and OLF

Several electrophysiologic methods have been used for intraoperative monitoring of spinal cord functions. Recently, muscle responses following transcranial electric stimulation have also been widely used. However, in patients with severe myelopathy, only the spinal cord responses following spinal cord stimulation can be recorded. We report a false-negative case in monitoring using spinal cord responses following spinal cord stimulation. The patient presented with severe thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum. Spinal cord responses following spinal cord stimulation were recorded during laminectomy and partial removal of the OPLL. Although the amplitude of those responses decreased transiently to within 50% of control data during decompression, it had recovered to the control level by the end of surgery. Just after surgery, the patient showed complete motor paralysis with preserved sensory function. Spinal cord responses following spinal cord stimulation can be recorded in patients with severe myelopathy. However, motor problems may occur when surgery is continued in the false belief that responses are accurate.     

Equipment for spinal cord stimulation

Spinal cord stimulation has gained widespread popularity for the treatment of pain. This literature discribed our equipments, methods, patient selection, and operative procedures for spinal cord stimulation.     

Spinal cord stimulation

The use of spinal cord stimulation has been shown to be not only effective in 50% to 80% of patients with chronic pain related to radiculopathies or nerve injury but also cost effective. The better understanding of the mechanisms of the technique has led to better technology such as dual stimulation, which has improved the quality of analgesia, and computer programming, which will enable several different stimulating combinations. New horizons are being explored for the use of this technique. This report attempts to provide a reference for the use of this technique at the beginning of the 21st century. Copyright © 2000 by W.B. Saunders Company