Lumbar Sympathetic Block for Intractable Lower-Limb Postherpetic Neuralgia: Report of Two Cases

Lumbar sympathetic block is a commonly used technique for sympathetically mediated pain syndromes. Postherpetic neuralgia (PHN) is also accepted to be associated with sympathetic system activation. While sympathetic blocks were utilized for upper-extremity or face-related PHN, there has not been any report regarding lower-extremity PHN, as it is an uncommon region. Here, we present two cases of systemic drug-resistant PHN in lower limb, relieved with lumbar sympathetic block. Both patients had at least 50% reduction in numeric rating scale (NRS) scores at the end of 6 months. Lumbar sympathetic block could be considered in the treatment of lower-limb PHN. More reports and controlled trials are needed for further understanding the role of the intervention in this neuropathic pain syndrome.     

Neural Modulation by Stimulation

Abstract:   Spinal cord stimulation (SCS) for the treatment of neuropathic pain is supported by good-quality randomized controlled trials, prospective and retrospective case studies, and observational case series that confirm its efficacy and safety. SCS has been successfully used in various refractory neuropathic pain conditions, including failed back surgery syndrome (FBSS), neuropathic back and leg pain, and complex regional pain syndrome (CRPS) types I and II. According to the Harbour and Miller Scale (2001), the evidence for SCS in FBSS has been classified as grade B, while that for CRPS type I has been classified as grade A. Clinical evidence has shown that compared to conventional pain therapy, more than two-thirds of carefully selected patients treated with SCS achieved sustained pain relief of 50% or more, with minimal side effects. Many patients were able to reduce their analgesic consumption. Quality of life improved and the majority of patients were happy with their treatment; in some cases, patients were able to return to work. Trial stimulation, which is relatively inexpensive and completely reversible, provides predictive value for long-term efficacy and increases the cost-effectiveness of permanent implantation. Studies consistently report that over time, SCS is potentially cost saving to the healthcare system. At present, SCS is considered a "last resort" in the treatment of refractory neuropathic pain, yet evidence suggests that early intervention with SCS results in greater efficacy and, in the case of FBSS, should be considered before re-operation.     

Exercise-Induced Modulation of Pain in Adults With and Without Painful Diabetic Neuropathy

The purpose of this study was to examine exercise-induced pain modulation in diabetic adults with painful diabetic neuropathy (PDN) compared to diabetic adults without PDN. Eighteen adults diagnosed with type 2 diabetes with and without PDN (mean age of 49 years) completed 2 sessions. During the familiarization session, participants completed questionnaires, were familiarized with the pain testing protocols, and completed maximal isometric contractions. During the exercise session, experimental pain testing was completed before and following exercise consisting of 3 minutes of isometric exercise performed at 25% maximal voluntary contraction. Ratings of perceived exertion and muscle pain were assessed every 30 seconds during exercise. Results indicated that ratings of perceived exertion and muscle pain during exercise were significantly higher (P < .05) for diabetic adults with PDN versus diabetic adults without PDN. Diabetic adults with PDN did not experience changes in thermal pain ratings following exercise, whereas diabetic adults without PDN reported significantly lower pain ratings following exercise. It is concluded that diabetic adults with PDN experienced high levels of muscle pain during exercise and a lack of exercise-induced hypoalgesia following exercise, in comparison to diabetic adults without PDN, who experienced lower levels of muscle pain during exercise and a hypoalgesic response following exercise.PerspectiveVery little research has been conducted examining the impact of exercise on pain modulation in diabetic adults with PDN. This study provides support that adults with PDN exhibit exercise-induced endogenous pain modulatory system dysfunction.     

The Effects of Streptomycin/Lidocaine Block on Trigeminal Neuralgia: A Double Blind Crossover Placebo Controlled Study

SYNOPSIS
This study investigated the long term effect of a peripheral sensory block using streptomycin sulphate on trigeminal neuralgia. A total of twenty subjects, thirteen with idiopathic trigeminal neuralgia (ITN) and seven with traumatic trigeminal neuralgia (TTN) were studied. A double-blind placebo controlled randomized design was used. After the clinical assessment subjects were randomly assigned to receive either 1 g of streptomycin with 3 ml 2% lidocaine, or 3 ml lidocaine alone. The injections were performed adjacent to the branches that served the painful site. These were intraoral injections, more specifically infraorbital and inferior alveolar blocks. Patients received five blocks of either streptomycin/lidocaine or lidocaine alone for a period of five consecutive weeks. On the sixth week they were crossed over. Measures of pain intensity and pain frequency were used to assess treatment outcome. Patients also recorded their side-effects. Repeated measures analysis of variance was used to compare the treatment outcomes between the active and placebo groups. There was no statistically significant differences in the treatment outcomes regarding frequency and intensity of pain attacks. The sensory function of the treated nerves was also not affected. Side effects including facial swelling and pain were a common finding in the patients receiving streptomycin. This study demostrated no beneficial effects of streptomycin blockade for idiopathic and traumatic trigeminal neuralgia.     

Outcome Prediction Following Sympathetic Block for Complex Regional Pain Syndrome

Abstract:   Evidence for the efficacy of sympathetic blocks as either diagnostic or therapeutic tools in complex regional pain syndrome (CRPS) remains anecdotal. Systematic evaluation has been confounded by inconsistent terminology, difficulties in objectively quantifying physical findings, and failure to control for co-morbid psychological factors. This study examines the relative contribution of physical and psychometric features as prospective predictors of outcome following sympathetic block in the treatment of CRPS. Twenty patients with CRPS characterized by mechanical allodynia and vasomotor/sudomotor disturbance were treated with sympathetic blocks. Long-term outcome was assessed at > 6 months following the last treatment using a mailed questionnaire. Pain relief and functional improvement were negatively influenced by anxiety ( P  < 0.001). When the improvement in the initial visual analog for pain (VAS) was 50% or greater following "diagnostic" sympathetic block, the percent improvement was highly correlated with improvement at long-term follow-up ( P  < 0.001). Higher "sensitivity" scores on the Neuropathic Pain Scale ( P  < 0.001), C fiber allodynia ( P  < 0.01) and Aδ-fiber allodynia ( P  < 0.01) on quantitative sensory testing, and pretreatment reported dynamic mechanical allodynia ( P  < 0.02) all predicted positive response to initial sympathetic block. While sympathetic blocks can be helpful in the reduction of mechanical allodynia, and thus the facilitation of physical and occupational therapy, ultimate response to a regime that includes medications is not predicted by sympathetic block alone.     

腰交感神经阻滞术在癌性腰腿痛治疗中的应用

晚期癌患者４例（男３，女１）因腰２、腰３椎体及骼骨转移伴严重腰腿痛，在ＣＴ引导下行腰交感神经酒精阻滞治疗，获得了满意的治疗效果。患者疼痛评分（ＶＡＳ）从治疗前的９￣１０（平均９．７５）降至治疗后的１￣３（平均２），而且完全撤掉了治疗前所必需的较大剂量的麻醉性止痛药。２例同时伴有下肢Ⅲ￣Ⅳ度水肿的患者，经治疗后降至０￣１度。神经阻滞穿刺过程中及之后均未出现严重并发症。     

Combined Sciatic and Lumbar Plexus Nerve Blocks for the Analgesic Management of Hip Arthroscopy Procedures: A Retrospective Review

Hip arthroscopy is a minimally invasive alternative to open hip surgery. Despite its minimally invasive nature, there can still be significant reported pain following these procedures. The impact of combined sciatic and lumbar plexus nerve blocks on postoperative pain scores and opioid consumption in patients undergoing hip arthroscopy was investigated. A retrospective analysis of 176 patients revealed that compared with patients with no preoperative peripheral nerve block, significant reductions in pain scores to 24 hours were reported and decreased opioid consumption during the post anesthesia care unit (PACU) stay was recorded; no significant differences in opioid consumption out to 24 hours were discovered. A subgroup analysis comparing two approaches to the sciatic nerve block in patients receiving the additional lumbar plexus nerve block failed to reveal a significant difference for this patient population. We conclude that peripheral nerve blockade can be a useful analgesic modality for patients undergoing hip arthroscopy.     

16. Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy is a pain syndrome with an unclear pathophysiology and unpredictable clinical course. The disease is often therapy resistant, the natural course not always favorable. The diagnosis of CRPS is based on signs and symptoms derived from medical history and physical examination. Pharmacological pain management and physical rehabilitation of limb function are the main pillars of therapy and should be started as early as possible. If, however, there is no improvement of limb function and persistent severe pain, interventional pain management techniques may be considered. Intravenous regional blocks with guanethidine did not prove superior to placebo but frequent side effects occurred.Therefore this technique receives a negative recommendation (2 A–). Sympathetic block is the interventional treatment of first choice and has a 2 B+ rating. Ganglion stellatum (stellate ganglion) block with repeated local anesthetic injections or by radiofrequency denervation after positive diagnostic block is documented in prospective and retrospective trials in patients suffering from upper limb CRPS. Lumbar sympathetic blocks can be performed with repeated local anesthetic injections. For a more prolonged lumbar sympathetic block radiofrequency treatment is preferred over phenol neurolysis because effects are comparable whereas the risk for side effects is lower (2 B+). For patients suffering from CRPS refractory to conventional treatment and sympathetic blocks, plexus brachialis block or continuous epidural infusion analgesia coupled with exercise therapy may be tried (2 C+). Spinal cord stimulation is recommended if other treatments fail to improve pain and dysfunction (2 B+). Alternatively peripheral nerve stimulation can be considered, preferentially in study conditions (2 C+).     

Neuropathic Pain with Features of Complex Regional Syndrome in the Upper Extremity after Herpes Zoster

We report a case of a 73‐year‐old female who developed unbearable neuropathic pain after a herpes zoster episode. The pain persisted and could not be controlled despite multimodal analgesia. In addition to postherpetic neuralgia, myelitis and complex regional pain syndrome were diagnosed during the evolution of neuropathic pain. This complex neuropathic pain was resolved after sympathetic ganglion block.     

Occipital nerve block is effective in craniofacial neuralgias but not in idiopathic persistent facial pain

Occipital nerve block (ONB) has been used in several primary headache syndromes with good results. Information on its effects in facial pain is sparse. In this chart review, the efficacy of ONB using lidocaine and dexamethasone was evaluated in 20 patients with craniofacial pain syndromes comprising 8 patients with trigeminal neuralgia, 6 with trigeminal neuropathic pain, 5 with persistent idiopathic facial pain and 1 with occipital neuralgia. Response was defined as an at least 50% reduction of original pain. Mean response rate was 55% with greatest efficacy in trigeminal (75%) and occipital neuralgia (100%) and less efficacy in trigeminal neuropathic pain (50%) and persistent idiopathic facial pain (20%). The effects lasted for an average of 27 days with sustained benefits for 69, 77 and 107 days in three patients. Side effects were reported in 50%, albeit transient and mild in nature. ONBs are effective in trigeminal pain involving the second and third branch and seem to be most effective in craniofacial neuralgias. They should be considered in facial pain before more invasive approaches, such as thermocoagulation or vascular decompression, are performed, given that side effects are mild and the procedure is minimally invasive.