Gerbrand J. Groen

Radiofrequency denervation of lumbar facet joints in the treatment of chronic low back pain: a randomized, double-blind, sham lesion-controlled trial.

Objectives:Radiofrequency facet joint denervation procedures have been common practice for 2 decades in treatment of chronic low back pain. We designed this multicenter, randomized, double-blind, sham treatment controlled trial to determine the efficacy of radiofrequency facet joint denervation, as it is routinely performed. Methods:Inclusion criteria were low back pain, duration more than 6 months, and ≥50% Visual Analog Scale (VAS) reduction on diagnostic block. Exclusion criteria were prior radiofrequency treatment, radicular syndrome, coagulopathies, specific allergies, cancer, and pregnancy. A total of 81 out of 462 patients were randomized to undergo radiofrequency facet joint denervation or sham treatment. The first evaluation was carried out 3 months after treatment. Primary outcome was determined with a combined outcome measure comprising VAS, physical activities, and analgesic intake, from a twice-weekly recorded diary. Secondary outcome measures were the separate diary parameters, global perceived effect (complete relief, >50% relief, no effect, pain increase), and SF-36 Quality of Life Questionnaire. Results:There were no dropouts before the first evaluation. The combined outcome measure showed no differences between radio- frequency facet joint denervation (n = 40; success 27.5%) and sham (n = 41; success 29.3%) (P = 0.86). The VAS in both groups improved (P < 0.001). Global perceived effect improved after radiofrequency facet joint denervation (P < 0.05). The other secondary outcome parameters showed no significant differences. Relevant costs were evaluated. Discussion:The combined outcome measure and VAS showed no difference between radiofrequency and sham, though in both groups, significant VAS improvement occurred. The global perceived effect was in favor of radiofrequency. In selected patients, radiofrequency facet joint denervation appears to be more effective than sham treatment.

efficacy of Radiofrequency Procedures for the Treatment of Spinal Pain : a Systematic Review of Randomized Clinical Trials

Background and Objectives The use of radiofrequency (RF) procedures in the peripheral nervous system to treat chronic spinal pain has been the subject of controversy. Publications concerned only uncontrolled studies, and irreversible nervous tissue damage was believed to be responsible for the effect, if any. In recent years, randomized, controlled studies have appeared, which have attested to an increasing use of these techniques. This is a systematic review of randomized controlled trials on RF procedures for spinal pain. Methods We performed a standardized literature search for randomized, controlled trials. Three adjudicators independently registered trial methodology and outcome using validated and subject-related instruments. Interadjudicator disagreement was resolved by discussion. It was found necessary to devise additional parameters of study assessment. Results Six trials met the inclusion criteria. This small number, along with clinical and technical heterogeneity precluded statistical analysis. All studies, whether high or low quality, reported positive outcomes. Conclusions We conclude that there is moderate evidence that RF lumbar facet denervation is more effective for chronic low back pain than placebo. Limited evidence exists for efficacy of RF neurotomy in chronic cervical zygapophyseal joint pain after flexion-extension injury. There is limited evidence that RF heating of the dorsal root ganglion is more effective than placebo in chronic cervicobrachialgia. We recommend the systematic application of our additional parameter assessments for future evaluations of RF studies. These additional parameters should also be used in the preparation of future trial protocols of RF procedures for the treatment of chronic pain.

Extraneural versus Intraneural Stimulation Thresholds during Ultrasound-guided Supraclavicular Block

Background:A stimulation current of no more than 0.5mA is regarded as safe in avoiding nerve injury and delivering adequate stimulus to provoke a motor response. However, there is no consistent level of stimulating threshold that reliably indicates intraneural placement of the needle. The authors determined the minimally required stimulation threshold to elicit a motor response outside and inside the most superficial part of the brachial plexus during high-resolution, ultrasound-guided, supraclavicular block. Methods:After institutional review board approval, ultrasound-guided, supraclavicular block was performed on 55 patients. Patients with neurologic dysfunction were excluded. Criteria for extraneural and intraneural stimulation were defined and assessed by independent experts. To determine success rate and any residual neurologic deficit, qualitative sensory and motor examinations were performed before and after block placement. At 6 month follow-up, the patients were examined for any neurologic deficit. Results:Thirty-nine patients met all set stimulation criteria. Median ± SD (interquartile range) minimum stimulation threshold outside was 0.60 ± 0.37 mA (0.40, 1.0) and inside 0.30 ± 0.19 mA (0.20, 0.40). The difference of 0.30 mA was statistically significant (P < 0.0001). Stimulation currents of 0.2 mA or less were not observed outside the trunk in any patient. Significantly higher thresholds were observed in diabetic patients. Success rate was 100% after 20 min. Thirty-four patients had normal sensory and motor examination at 6 months. Five patients were lost to follow-up. Conclusion:Within the limitations of this study and the use of ultrasound, a stimulation current of 0.2 mA or less is reliable to detect intraneural placement of the needle. Furthermore, stimulation currents of more than 0.2 and no more than 0.5 mA could not rule out intraneural position.

Radiofrequency lesioning of dorsal root ganglia for chronic lumbosacral radicular pain: a randomised, double-lind, controlled trial

BACKGROUND Results of observational studies have shown pain reduction with percutaneous radiofrequency lesioning of dorsal root ganglia for lumbosacral radicular pain, but there are few randomised controlled trials. We aimed to assess the efficacy of radiofrequency lesioning of dorsal root ganglia for lumbosacral radicular pain. METHODS We screened 1001 patients, who were mostly referred by their family doctor, in four hospitals for a double-blind randomised trial. 83 patients met inclusion criteria and thus were randomly assigned to receive a radiofrequency lesion or control treatment of the involved dorsal root ganglion. Control treatment was done in the same way as radiofrequency lesioning, but without radiofrequency current. Preoperatively and during 3-month follow-up, patients reported visual analogue leg-pain and back-pain scores, physical impairment, and use of analgesics in a diary. Primary outcome was success or failure of treatment, defined by a multidimensional decision rule, which included median outcome variables from the diary. Post-hoc analysis for possible covariate interference with outcome variables was done. Primary outcome data were analysed on an intention-to-treat basis. FINDINGS 45 patients were assigned radiofrequency lesioning and 38 control treatment. Three patients dropped out before 3 months. After 3 months, seven (16%) of 44 patients treated with radiofrequency lesioning and nine (25%) of 36 in the control group had successful treatment (difference -9.1% [95% CI -33.0 to 12.0], p=0.43). No differences between groups in side-effects were seen. INTERPRETATION Lumbosacral radiofrequency lesioning of dorsal root ganglia failed to show advantage over control treatment with local anaesthetics. Thus, its use as routine treatment in lumbosacral radicular pain should not be advocated.

Quantitative Architecture of the Brachial Plexus and Surrounding Compartments, and Their Possible Significance for Plexus Blocks

Background:Nerve injury after regional anesthesia of the brachial plexus (BP) is a relatively rare and feared complication that is partly attributed to intraneural injection. However, recent studies have shown that intraneural injection does not invariably cause neural injury, which may be related to the architecture within the epineurium. A quantitative study of the neural components and the compartment outside BP was made. Methods:From four frozen shoulders, high-resolution images of sagittal cross-sections with an interval of 0.078 mm were obtained using a cryomicrotome to maintain a relatively undisturbed anatomy. From this data set, cross-sections perpendicular to the axis of the BP were reconstructed in the interscalene, supraclavicular, midinfraclavicular, and subcoracoid regions. Surface areas of both intraepineurial and connective tissue compartments outside the BP were delineated and measured. Results:The nonneural tissue (stroma and connective tissue) inside and outside the BP increased from proximal to distal, being significant between interscalene/supraclavicular and midinfraclavicular/subcoracoid regions (P < 0.001 for tissue inside BP, P < 0.02 for tissue outside BP). The median amount of neural tissue remained approximately the same in the four measured regions (41.1 ± 6.3 mm2; range, 30–60 mm2). The ratio of neural to nonneural tissue inside the epineurium increased from 1:1 in the interscalene/supraclavicular to 1:2 in the midinfraclavicular/subcoracoid regions. Conclusion:Marked differences in neural architecture and size of surrounding adipose tissue compartments are demonstrated between proximal and distal parts of the brachial plexus. These differences may explain why some injections within the epineurium do not result in neural injury and affect onset times of BP blocks.

Targeted methylprednisolone acetate/hyaluronidase/clonidine injection after diagnostic epiduroscopy for chronic sciatica: A prospective, 1-year follow-up study

Background and Objectives It has been claimed that epiduroscopy offers an ideal combination of diagnostic and therapeutic interventions in one session. We prospectively evaluated whether abnormalities at the lumbar level as diagnosed by magnetic resonance imaging (MRI) are confirmed by epiduroscopy, and assessed if targeted epidural injection of medication alleviates sciatic pain. Methods A flexible, 0.9-mm fiberoptic endoscope was introduced through a disposable steering shaft into the caudal epidural space and advanced until the targeted spinal nerve was identified. Adhesions were mechanically mobilized under direct vision, and a mixture of 120 mg methylprednisolone acetate, 600 IU hyaluronidase, and 150 μg clonidine was applied locally. Pain scores were measured by visual analog scale (VAS) and global subjective efficacy rating. Results Nineteen of 20 patients studied showed adhesions via epiduroscopy. In 8 patients, 6 of whom had never undergone surgery, these were not detected with earlier magnetic resonance imaging. Six patients showed concomitant signs of active root inflammation. Of 20 patients treated with a targeted epidural injection, 11 patients (55%) experienced significant pain relief at 3 months. This was maintained at 6, 9, and 12 months for 8 (40%), 7 (35%), and 7 (35%) patients, respectively. Mean VAS at 3 months was significantly reduced (n = 20; ΔVAS = 3.55; P < .0001), and this persisted at 12 months (ΔVAS = 1.99, P = .0073). Conclusions Epiduroscopy is of value in the diagnosis of spinal root pathology. In sciatica, adhesions unreported by MRI can be identified. Targeted epidural medication, administered near the compromised spinal nerve, results in substantial and prolonged pain relief.

Percutaneous facet denervation in chronic thoracic spinal pain

SummaryIn 40 patients with chronic thoracic spinal pain of more than 12 months duration which failed to respond to conservative treatment and with a previous evaluation by specialists, mainly neurologists and orthopaedic surgeons, the diagnosis of facet syndrome was made. This diagnosis was based on clinical criteria and a transient positive response to a prognostic blockade of the medial branch of the dorsal ramus of the thoracic spinal nerve. They were selected to undergo percutaneous radiofrequency denervation of the facet joints. The short and long-term results of 51 percutaneous thoracic facet denervations in 40 patients are described. After 2 months, 19 patients (47.5%) were pain-free, 14 patients (35%) had more than 50% pain-relief, and 7 patients (17.5%) had no relief. After a follow-up of 18–54 (average 31) months in 36 cases (3 patients had died because of malignancy, and 1 had undergone a spinal fusion), 16 patients (44%) were pain-free, 14 patients (39%) had more than 50% pain-relief and in 6 cases (17%) the result was poor. Adverse effects consisted of postoperative pain in 5 patients (12.5%). When conservative treatment fails, percutaneous thoracic facet denervation can be a safe and beneficial therapy in chronic thoracic spinal pain originating from the facet joints.

The management of chronic spinal pain by blockades: a review

This review of the use of blockades in the diagnosis and symptomatic treatment of spinal pain syndromes is based on increasing knowledge of the innervation of the spine as their rationale. Several clinical syndromes related to the spine are considered. Problems in making a correct diagnosis are discussed. Because of the relative aspecificity of signs and symptoms in spinal pain, a substantial part of the diagnosis may rely on test blockades. The place of test and therapeutic blocks is determined as far as possible. Problems of a pain classification system are discussed. Benefit for the patient depends on the following conditions being achieved: correct diagnosis, careful patient selection, the availability of technical equipment (e.g., fluoroscopy), and a well-designed and well-performed technique in experienced hands.

The Innervation of the Spinal Dura mater: Anatomy and Clinical Implications

SummaryThe nerves supplying the spinal dura mater were studied in four human foetuses (16–22 weeks) with the acetylcholinesterasein toto staining method.The ventral spinal dura contains a dense, longitudinally oriented, nerve plexus, which receives its contributions from: (I) the sinuvertebral nerves, (II) the nerve plexus of the posterior longitudinal ligament, (III) the nerve plexus of radicular branches of segmental arteries.Dorsal dural nerves are much smaller in number, do not form an evident plexus and do not reach the medial region of the dorsal dura. The dorsal nerves are derived from the ventral dural plexus at the level of the “intersleeval” parts of the dura mater.The ventral dural nerves may extend up to eight segments, with a great amount of overlap between adjacent nerves. This may provide an anatomical substrate for the understanding of extrasegmentally referred dural pain. The curled bundles of nerve fibres of pathways (I) and (II) provide an adequate adaptation to displacements of the spinal dura mater during flexion and extension. Pathway (III) has not been described before. The described nerve plexuses may be of importance in elucidating the mechanisms of epidural therapies in back pain and peripheral vascular disease.

15. Discogenic Low Back Pain

An estimated 40% of chronic lumbosacral spinal pain is attributed to the discus intervertebralis. Degenerative changes following loss of hydration of the nucleus pulposus lead to circumferential or radial tears within the annulus fibrosus. Annular tears within the outer annulus stimulate the ingrowth of blood vessels and accompanying nociceptors into the outer and occasionally inner annulus. Sensitization of these nociceptors by various inflammatory repair mechanisms may lead to chronic discogenic pain.