This randomized controlled trial is the first to show the effectiveness and tolerance of a medication, low-dose amitriptyline, in managing idiopathic chronic neck pain and its related comorbidities. The optimal treatment of this condition was still controversial in the literature. It extends the indication of low-dose amitriptyline to another chronic pain condition.
ObjectRadiofrequency (RF) ablation is a minimally invasive technique often used percutaneously in the treatment of many conditions such as spasticity, pain, and osteoid osteoma. The purpose of this study was to assess the value of motor response threshold (MRT) as an indirect indicator of the RF generator's electrode to nerve distance, and to evaluate the effects of RF at various distances from a nervous structure.MethodsThe L-5 nerve root was studied in 102 Sprague-Dawley rats (sham contralateral side). Motor response thresholds at 0, 2, 4, 5, and 6 mm from the nerve root were assessed before and after RF application for 2 minutes at 80° C on Days 0 and 7. Radiofrequency was applied 0, 2, 4, 5, and 6 mm away from L-5 and with the addition of interposed cortical bone. The effects of RF application on MRT were studied, and subsequent nerve injury was evaluated using light microscopy pathological examination.ResultsThere is a significant correlation between MRT and the distance between the electrode tip and L-5, with MRT less than 0.5 V when the electrode was in direct contact with the root. Electrical and pathological changes following RF application were more pronounced at 0 mm, with worsening seen on Day 7. Radiofrequency at 2 and 4 mm produced fewer electrical and histological deleterious effects on the nerve on Days 0 and 7, with an obvious improvement on Day 7. At 5 mm, electrical and histological abnormalities were minimal on Day 0 and were fully reversible on Day 7. At 6 mm and with interposed cortical bone, MRT and pathological findings were unchanged on Days 0 and 7.ConclusionsThe MRT proved to be a useful and reliable tool in decreasing nerve morbidity following RF ablation in animals and may be used in humans for the same purpose. It serves as an indirect indicator of the proximity of the RF generator's electrode tip to any adjacent motor nervous structure. A minimum safe distance of 5 mm between the electrode tip and the nerve is required to avoid irreversible nerve injury, unless a bony wall is interposed between them, thus serving as a nerve shield. In medical conditions that require RF ablation of the nerve, such as spasticity and pain, the MRT must be lower than 0.5 V. When a nerve lesion is to be avoided such as in cases of osteoid osteoma, an MRT higher than 2.5 V is considered safe, reflecting a distance greater than 5 mm.
OBJECTIVESurgery has been considered the standard treatment for spinal osteoid osteomas that are refractory to analgesic agents. Radiofrequency ablation (RFA) is a less invasive technique with established efficiency for the treatment of peripheral osteoid osteomas. The main objectives of this study are to evaluate the safety of RFA based on the results of a previous experimental study in rats conducted in the authors' laboratory and to identify its short- and long-term efficiency in the treatment of spinal osteoid osteomas.METHODSBetween March 2009 and July 2016, 8 consecutive patients with spinal osteoid osteomas were enrolled in the study and underwent 9 CT-guided RFA procedures. All patients presented with spinal pain (median preoperative visual analog scale [VAS] score 7.55, range 6–8.8) predominantly during the night, and they all had normal neurological examination results before the procedure. Pain (according to the VAS score) and neurological status were reassessed immediately before discharge, with further follow-up at 1, 6, and 12 months after the procedure. At the final follow-up, VAS score, neurological examination, patient satisfaction, and a radiological control (CT scan) were documented (median 48 months, range 12–84 months). VAS scores before and after the procedure were compared during the 3 days before surgery (D0), on the day of the surgery, Day 1 (D1), and at the final follow-up.RESULTSNo neurological deficit was documented following the procedure or at the final follow-up. A statistically significant reduction in the VAS score was observed on Day 1 (mean 2.56 ± 0.68, p = 0.005) compared with D0. At the final follow-up, all patients reported a VAS score of 0 and a satisfaction rate of 100%. Only 1 patient had recurrent symptoms (pain, VAS score 8.1) 6 months after the initial RFA. A second procedure was performed, and the patient was subsequently symptom free at the final follow-up. CT scanning performed in all patients (12–84 months post-RFA) showed residual sclerosis in 4 patients and complete resolution of the radiological lesion in the remaining 4 patients.CONCLUSIONSCT-guided RFA appears to be a safe and effective method for the management of spinal osteoid osteoma and can be safely performed for lesions close to the dura or exiting nerve root based on the motor response threshold testing performed during the procedure. It should be considered the treatment of choice for spinal osteoid osteomas refractory to conservative treatment, thus avoiding more aggressive spinal approaches with subsequent potential morbidity.
The addition of clonidine to local preincisional field block with bupivacaine resulted in better and prolonged postoperative analgesia in posterior lumbar spine surgeries, an effect that was more pronounced in patients with no preoperative spinal pain.
Although motor cortex stimulation (MCS) is being increasingly used to treat chronic refractory neuropathic pain in humans, its mechanisms of action remain elusive. Studies in animals have suggested the involvement of subcortical structures, in particular, the thalamus. Most of these studies have been performed in rats, a species presenting significant differences in thalamic anatomy and function relative to primates, in particular, a very limited number of thalamic GABA interneurons. The aim of this study was to investigate the effects of MCS on single-unit activities of the thalamic ventral posterior lateral (VPL) nucleus in cats, which contains substantial numbers of GABA interneurons. Spontaneous and evoked activities of VPL units were studied before and after MCS. Motor cortex stimulation induced significant depression of the wide-dynamic-range (WDR) cells' firing rate, concomitant with activity enhancement of nonnociceptive (NN) units. More than half of WDR cells showed a significant decrease in the firing rate, while a similar proportion of NN units exhibited the opposite after-effect. Maximal firing attenuation of WDR cells occurred when the MCS location matched somatotopically their receptive field. Repetition of MCS runs led to an accentuation of WDR depression. After peripheral stimulation, evoked activity in each cell showed MCS effects similar to those observed in spontaneous activity. These data demonstrate a selective top-down inhibition by MCS of nonspecific nociceptive (WDR) cells, enhanced by somatotopic concordance and stimulation repetition, in parallel to facilitation of NN cells. These 2 outcomes may play a role in the complex analgesic effect of MCS observed in neuropathic pain conditions.
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