Gerard A. M. Barendse

Effect of spinal cord stimulation for chronic complex regional pain syndrome Type I: five-year final follow-up of patients in a randomized controlled trial

OBJECT Chronic complex regional pain syndrome-Type I (CRPS-I) is a painful, disabling disorder for which no treatment with proven effect is available. In the present randomized controlled trial, the authors assessed the effectiveness of spinal cord stimulation (SCS) in reducing pain due to CRPS-I at the 5-year follow-up. METHODS The authors performed a randomized trial in a 2:1 ratio in which 36 patients with CRPS-I were allocated to receive SCS and physical therapy (PT) and 18 patients to receive PT alone. Twenty-four patients who received SCS+PT also underwent placement of a permanent spinal cord stimulator after successful test stimulation; the remaining 12 patients did not receive a permanent stimulator. The authors assessed pain intensity, global perceived effect, treatment satisfaction, and health-related quality of life. Patients were examined before randomization, before implantation, and every year until 5 years thereafter. Ten patients were excluded from the final analysis. RESULTS At 5 years posttreatment, SCS+PT produced results similar to those following PT for pain relief and all other measured variables. In a subgroup analysis, the results with regard to global perceived effect (p=0.02) and pain relief (p=0.06) in 20 patients with an implant exceeded those in 13 patients who received PT. CONCLUSIONS Despite the diminishing effectiveness of SCS over time, 95% of patients with an implant would repeat the treatment for the same result.

The effect of spinal cord stimulation in patients with chronic reflex sympathetic dystrophy: Two years' follow-up of the randomized controlled trial

Chronic reflex sympathetic dystrophy is a painful, disabling disorder for which no treatment with proven effect is available. We performed a randomized trial in a 2 to 1 ratio of patients, in which 36 patients were treated with spinal cord stimulation and physical therapy (SCS+PT), and 18 patients received solely PT. Twenty‐four SCS+PT patients were given a permanent spinal cord stimulation system after successful test stimulation; the remaining 12 patients received no permanent system. We assessed pain intensity, global perceived effect, functional status, and health‐related quality of life. Patients were examined before randomization, before implantation, and also at 1, 3, 6, 12, and 24 months thereafter. At 2 years, three patients were excluded from the analysis. The intention‐to‐treat analysis showed improvements in the SCS+PT group concerning pain intensity (−2.1 vs 0.0cm; p < 0.001) and global perceived effect (43% vs 6% “much improved”; p = 0.001). There was no clinically important improvement of functional status. Health‐related quality of life improved only in the group receiving spinal cord stimulation. After careful selection and successful test stimulation, spinal cord stimulation results in a long‐term pain reduction and health‐related quality of life improvement in chronic reflex sympathetic dystrophy.

Randomized controlled trial of percutaneous intradiscal radiofrequency thermocoagulation for chronic discogenic back pain: lack of effect from a 90-second 70 C lesion.

Study Design. A prospective double-blind randomized trial in 28 patients. Objectives. To assess the clinical effect of percutaneous intradiscal radiofrequency thermocoagulation for reducing pain, functional disability, and physical impairment in patients with chronic discogenic low back pain. Summary of Background Data. Chronic discogenic low back pain is a challenging problem in western countries. A treatment option is radiofrequency heating of the affected disc. Its clinical efficacy has never been formally tested in a controlled trial. Methods. Twenty-eight patients with a history of at least 1 year of chronic low back pain were selected on the basis of a diagnostic anesthetization of the lower intervertebral discs. Only patients with one putative painful level were selected and randomly assigned to one of two treatment groups. Each patient in the radiofrequency treatment group (n = 13) received a 90-second 70 C lesion of the intervertebral disc. Patients in the control group (n = 15) underwent the same procedure, but without use of radiofrequency current. Both the treating physician and the patients were blinded to the group assignment. Before treatment, physical impairment, rating of pain, the degree of disability, and quality of life were assessed by a blinded investigator. Results. Eight weeks after treatment, there was one success in the radiofrequency group (n = 13) and two in the control group (n = 15). The adjusted and unadjusted odds ratio was 0.5 and 1.1, respectively (not significant). Also, visual analog scores for pain, global perceived effect, and the Oswestry disability scale showed no differences between the two groups. Conclusions. Percutaneous intradiscal radiofrequency thermocoagulation (90 seconds, 70 C) is not effective in reducing chronic discogenic low back pain.

Effects and side effects of a percutaneous thermal lesion of the dorsal root ganglion in patients with cervical pain syndrome

&NA; Twenty consecutive patients with intractable chronic pain in the cervical region were treated with a radiofrequency lesion of the dorsal root ganglion on level C4, C5 or C6. Electromyography (EMG) and sensory evoked potentials (SEP) were recorded before and 3 weeks after the radiofrequency lesion. Side effects were studied 3 weeks, 6 weeks and 3 months after the procedure. Pain scores were evaluated on Numeric Rating Scales (NRS) before and 6 weeks after treatment. The patient was interviewed 3, 6 and 9 months after the radiofrequency lesion. The most common side effect was burning pain in the dermatome of the treated nerve root. Hyposensibility in the dermatome was noticed in 35% of patients. Except in 1 patient, these side effects had disappeared 6 weeks after treatment. The EMG showed no signs of denervation. One SEP recording remained abnormal after treatment. There was initial pain relief in 75% of patients after 3 months and in 50% of the patients after 6 months. In conclusion, this study did not reveal any signs of motor denervation after a percutaneous partial rhizotomy. There were no long‐term signs of deafferentation. Initial pain relief was found in 75% of patients, but there was a marked tendency for pain to recur in a period from 3 to 9 months after treatment.

Pain relief in complex regional pain syndrome due to spinal cord stimulation does not depend on vasodilation.

Background Spinal cord stimulation (SCS) is known to relieve pain in patients with complex regional pain syndrome (CRPS) and, in general, to cause vasodilation. The vasodilatory effect of SCS is hypothesized to be secondary to inhibition of sympathetically mediated vasoconstriction, or through antidromic impulses resulting in release of vasoactive substances. The aim of the present study was to assess whether pain relief in CRPS after SCS is, in fact, dependent on vasodilation. In addition, we tried to determine which of the potential mechanisms may cause the vasodilatory effect that is generally found after SCS. Methods Twenty-four of 36 patients with unilateral CRPS responded to the test of SCS. Twenty-two of these 24 responders (hand, n = 14; foot, n = 8) who had undergone previous sympathectomy were enrolled for the study. In addition, 20 control subjects (10 controls for each extremity) were studied. By means of laser Doppler flowmetry, the skin microcirculation of the patients was measured bilaterally while the SCS system was switched off and while it was activated. Control subjects (n = 20) were tested once only. The ratio of the rest flow at heart level and the dependent position was defined as the vasoconstriction index. Results Both in affected hands and feet, patients were found to have lower vasoconstriction indices (P < 0.01) as compared with controls, indicating a decreased sympathetic tone. Applying SCS did not result in any microcirculatory change as compared with baseline or the contralateral clinically unaffected side. Conclusions The current study failed to show that SCS influences skin microcirculation in patients with CRPS and a low sympathetic tone. Therefore, we may conclude that pain relief in CRPS due to SCS is possible without vasodilation. Because sympathetic activity was greatly decreased in our patients, these results support the hypothesis that the vasodilation that is normally found with SCS is due to an inhibitory effect on sympathetically maintained vasoconstriction.

Impact of spinal cord stimulation on sensory characteristics in complex regional pain syndrome type I - A randomized trial

BackgroundA randomized trial was performed to assess the effect of spinal cord stimulation (SCS) on detection and pain thresholds for pressure, warmth, and cold and on the extent of mechanical hyperalgesia in patients with chronic complex regional pain syndrome type I. MethodsFifty-four chronic complex regional pain syndrome type I patients were randomized to receive both SCS and physical therapy (SCS+PT; n = 36), or to receive only physical therapy (PT; n = 18). Twenty-four SCS+PT patients responded positively to trial stimulation and underwent SCS implantation. During a 12-month follow-up period, six quantitative sensory testing sessions were performed. The main analysis compared 24 SCS patients with 29 nonimplanted patients—one PT patient was excluded. ResultsSCS showed no effect on detection thresholds for warmth and cold or on pain thresholds for any sensation. The pressure detection threshold initially increased by SCS, but after 3 months, pressure detection thresholds returned to normal. Mechanical hyperalgesia, both dynamic and static, was reduced slightly with SCS. ConclusionsAlthough SCS has previously been shown to cause a significant pain reduction in complex regional pain syndrome type I, the treatment has no long-term effect on detection and pain thresholds for pressure, warmth, or cold. The treatment seems to have only minimal influence on mechanical hyperalgesia.

Relapsing ulcerative colitis associated with spinal cord stimulation.

Spinal cord stimulation is an increasingly popular form of pain treatment. An electrode positioned on the dorsal aspect of the spinal cord at the level of the nerve roots from the painful area stimulates the spinal cord. Current from the electrode is supplied by a pulse generator in the lower anterior abdominal wall. Spinal cord stimulation has not previously been associated with ulcerative colitis. A man with left-sided ulcerative colitis in remission experienced two successive relapses related to the use of a spinal cord stimulation system. After removal of the system, remission returned and remained. This case suggests that electrical current may influence the course of ulcerative colitis.

Thermal thresholds in complex regional pain syndrome type I: sensitivity and repeatability of the methods of limits and levels

OBJECTIVES To study whether the method of levels (MLE) or the method of limits (MLI) is preferable as a method of measuring thermal perception thresholds in patients with complex regional pain syndrome type I (CRPS I). METHODS Perception thresholds for warmth and cold were measured twice, with both MLE and MLI, at a 1 month interval, both at unaffected and affected wrists (n=33) or feet (n=20) of patients with CRPS I of one extremity. RESULTS (1) Sensitivity for pathology was equal for both methods. (2) The agreement between thresholds measured by both methods was low at all locations, except for the unaffected wrist. Since thresholds measured with the MLI always contain reaction time artefacts, this lack of agreement favours the MLE. (3) At both unaffected and affected wrists, the MLE showed significantly better coefficients of repeatability as compared to the MLI for both sensations. However, at both unaffected and affected feet, there was no preference for either method as far as threshold measurement repeatability was concerned. CONCLUSIONS Abnormal thermal perception thresholds occurred in 20% (foot) to 36% (wrist) of the CRPS I patients on the affected side and in 15% (foot, wrist) on the unaffected side. The MLE is considered to be the preferable method to assess thermal perception thresholds in CRPS I.

Local denervation of lumbar paraspinal muscles may not be used as a criterion for the effectivity of radiofrequency lesions of the zygapophyseal joints

AbstractA treatment option in a selected group of patients with chronic non-specific low back pain is percutaneous radiofrequency denervation of lumbar zygapophyseal joints (RDLZJ). These joints and the lumbar paravertebral musculature are innervated by the dorsal rami of the lumbar spinal nerves. It has been stated that the effectiveness of the procedure can be deduced from the finding of electromyographic signs of denervation in the paraspinal muscles. This study was designed to test the following: Does RDLZJ cause spontaneous muscle fibre activity of the paraspinal muscles? Is pain relief after a RDLZJ correlated with the presence of spontaneous activity in the paraspinal muscles?In a prospective observer-blind study, twenty-eight patients with a history of at least one year of chronic low back pain were selected on the basis of a positive response to a diagnostic nerve blockade and subsequently randomly assigned to one of two treatment groups. Each patient in the RF treatment-group (14 patients) recei...

Comment on ‘Ischaemic spinal cord lesion following percutaneous radiofrequency spinal rhizotomy’ by H.M. Koning, H.G. Koster and R.P.E. Niemeijer in PAIN, 45 (1991) 161–166

We would like to comment on the article by Dr. Koning et al. in which he describes two complications following a percutaneous radiofrequency rhizotomy [1]. Firstly, we object to the use of this type of treatment in these particular patients. Since postherpetic neuralgia is a deafferentation type of pain, we feel that RF lesions are contra-indicated in its treatment. The authors justify their choice of treatment by referring to an article by Pagura [2]. This article describes the results of percutaneous RF rhizotomies in 50 patients. Four out of those 50 patients had a postherpetic neuralgia. The result of treatment in those 4 patients is not separately mentioned. We conclude that this article does not offer a single argument for the use of RF lesions in the treatment of postherpetic neuralgia. Secondly, several technical questions remain obscure after reading the article. Radiological documentation of the position of the electrode is unfortunately missing. It is true that the ideal position is in the midfacetal line on the A-P projection and posteriorly in the foramen on the transverse projection. Extensive experience with this procedure has taught us that it is generally impossible to reach this position from a posterolateral approach in the superior thoracic region down to T5. Since the electrode cannot be inserted more laterally than the angle of the ribs, the approach to the foramen is necessarily so steep that the electrode invariably ends up either too far lateral or too far anterior. It is hardly conceivable that no technical difficulty has been encountered during the insertion of the electrode. This does not explain the complication which was described but we feel that simple, straightforward techniques generally do contribute to the avoidance of complications. Therefore we prefer a technique in which a small hole is drilled with a thin Kirschner wire through the lamina if a radiofrequency rhizotomy has to be performed in the upper thoracic area. It is a simple technique which is painless to the patient. It provides an ideal electrode position. Finally, we object to a rather loose use of references. The author states that an RF lesion with a fine thermocouple electrode is simple and safe. We do agree with that contention but the author then refers to an article by Uematsu et al. [3]. It is interesting to note that Uematsu who was the first author to describe this procedure used a thermistor electrode which was introduced through a 14-G needle. This technique was followed by other investigators, which inevitably led to complications such as deafferentation syndromes. This has discredited the procedure by Uematsu for a number of years.