OBJECTIVE: The distribution characteristics of intrathecal drugs and the limitation of current catheterization techniques make traditional intrathecal analgesic treatment nearly useless for refractory craniofacial pain, such as trigemina neuralgia. This technical guideline aims to promote the widespread and standardize the application of intra-prepontine cisternal drug delivery via spinal puncture and catheterization.
METHODS: A modified Delphi approach was used to work for this guideline. On the issues related to the intra-prepontine cisternal targeted drug delivery technique, the working group consulted 10 experts from the field with 3 rounds of email feedback and 3 rounds of conference discussion.
RESULTS: For the efficacy and safety of the intra-prepontine cisternal targeted drug delivery technique, a consensus was formed on 7 topics (with an agreement rate of more than 80%), including the principles of the technique, indications and contraindications, patient preparation, surgical specifications for intra-prepontine cisternal catheter placement, analgesic dosage coordination, analgesic management, and prevention and treatment of complications.
CONCLUSIONS: Utilizing the intra-prepontine cisternal drug infusion system to manage refractory craniofacial pain could provide advantages in terms of minimally invasive, secure, and effective treatment. This application can not only alleviate the suffering of individuals experiencing the prolonged pain but also support the maintenance of quality of life and dignity in their final moments, justifiing its widespread dissemination and standardized adoption in domestic and international professional fields.
目的: 鞘内镇痛药物的分布特点和目前置管技术的限制使传统的鞘内镇痛方法对头面部难治性疼痛无法发挥作用。本技术应用指南的制订旨在促进经脊柱椎间隙穿刺蛛网膜下腔脑桥前池置管药物输注技术的推广和规范、安全应用。方法: 工作小组采用改良德尔菲法，邀请本技术领域的10名专家对脑桥前池药物输注技术的相关议题进行3轮电子邮件函询及3轮现场会议讨论。结果: 针对脑桥前池药物输注技术的有效性和安全性，在技术原理、适应证和禁忌证、患者准备、脑桥前池置管手术规范、镇痛药物选择和剂量衔接、术后镇痛管理和并发症防治共7个议题形成一致意见(同意率≥80%)。结论: 脑桥前池药物输注镇痛技术应用于头面部难治性疼痛患者具有微创、安全、有效的优点，既可减轻长期罹受疼痛患者的痛苦，也能帮助一些患者保持人生最后一程的生活质量和生命尊严，值得在国内外相关专业领域推广和规范应用。.

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BACKGROUND: Persistent pain following breast surgery is common and may be challenging to treat. In patients refractory to conservative treatments, ultrasound-guided fascial plane blocks of thoracic nerves can be a useful option.
RESULTS: This type of neuro blockade technique provides advantages in terms of safety and efficacy that are convenient for physicians managing refractory and complex cases of post-breast surgery syndrome.
CONCLUSIONS: This technical review aims to present an up-to-date summary of the most common ultrasound-guided fascial plane blocks for chronic pain in post-breast surgery patients, provide a detailed technical description of each intervention, and propose preferred injections based on the anatomical location of the pain.

Painful sensitivity of the hand or foot are the most common and debilitating symptoms of complex regional pain syndrome (CRPS). Physical therapy is standard treatment for CRPS, but evidence supporting its efficacy is minimal and it can be essentially impossible for CRPS patients to actively exercise the painful limb. Using the well-characterized distal tibial fracture CRPS mouse model, we compared the therapeutic effects of several weeks of daily hindlimb loading versus rotarod walking exercise. The effects of loading and exercise were evaluated by weekly testing of hind-paw withdrawal thresholds to von Frey fibers and radiant heat, as well as measurements of paw and ankle edema. At 6 weeks after fracture, the mice were killed and the ipsilateral femur, spinal cord and L4/5 dorsal root ganglia, and hind-paw skin collected for PCR assays and paw skin Immunohistochemistry evaluation. Hindlimb loading reduced hind-paw von Frey allodynia and heat hyperalgesia and edema within a week and these effects persisted for at least a week after discontinuing treatment. These therapeutic effects of loading exceeded the beneficial effects observed with rotarod walking exercise in fracture mice. Levels of nerve growth factor and transient receptor potential vanilloid 1 (TRPV1) immunostaining in the hind-paw skin were increased at 6 weeks after fracture, and both loading and exercise treatment reduced increases. Collectively, these results suggest that loading may be an effective and possibly curative treatment in CRPS patients with sensitivity in the affected limb.

Complex regional pain syndrome is a chronic debilitating pain disorder that is difficult to manage, in part due to its heterogeneous clinical presentation and lack of clearly defined pathophysiology. Patients usually require a multidisciplinary approach to treatment, which can entail pharmacotherapy, physical therapy, behavioral therapy, and interventional pain procedures, such as sympathetic nerve blocks, spinal cord stimulation, and dorsal root ganglion stimulation. However, many patients continue to experience pain refractory to these multimodal strategies. Scrambler therapy (ST) is a noninvasive method of neuromodulation that is applied through cutaneous electrodes, and can alleviate chronic neuropathic pain by stimulating C-fibers and replacing endogenous pain signals with synthetic non-nociceptive signals. Although the use of ST has been reported for several types of refractory central and peripheral neuropathic pain, there is a paucity of data regarding the use of ST for complex regional pain syndrome. We present two patients with complex regional pain syndrome of the right lower extremity, who each underwent ST and experienced significant pain relief and improvement in function and quality of life.

OBJECTIVE: This study aimed to review the best evidence on the long-term efficacy of neurostimulation for chronic pain.
METHODS: We systematically reviewed PubMed, CENTRAL, and WikiStim for studies published between the inception of the data bases and July 21, 2022. Randomized controlled trials (RCTs) with a minimum of one-year follow-up that were of high methodologic quality as ascertained using the Delphi list criteria were included in the evidence synthesis. The primary outcome was long-term reduction in pain intensity, and the secondary outcomes were all other reported outcomes. Level of recommendation was graded from I to III, with level I being the highest level of recommendation.
RESULTS: Of the 7119 records screened, 24 RCTs were included in the evidence synthesis. Therapies with recommendations for their usage include pulsed radiofrequency (PRF) for postherpetic neuralgia, transcutaneous electrical nerve stimulation for trigeminal neuralgia, motor cortex stimulation for neuropathic pain and poststroke pain, deep brain stimulation for cluster headache, sphenopalatine ganglion stimulation for cluster headache, occipital nerve stimulation for migraine, peripheral nerve field stimulation for back pain, and spinal cord stimulation (SCS) for back and leg pain, nonsurgical back pain, persistent spinal pain syndrome, and painful diabetic neuropathy. Closed-loop SCS is recommended over open-loop SCS for back and leg pain. SCS is recommended over PRF for postherpetic neuralgia. Dorsal root ganglion stimulation is recommended over SCS for complex regional pain syndrome.
CONCLUSIONS: Neurostimulation is generally effective in the long term as an adjunctive treatment for chronic pain. Future studies should evaluate whether the multidisciplinary management of the physical perception of pain, affect, and social stressors is superior to their management alone.

Aim: Cryoneurolysis is a potential therapy for peripheral mononeuropathies, but randomized studies of its effects on the duration of pain reduction are lacking. Methods: This retrospective cohort study evaluated the analgesic effects of cryoneurolysis on patients with refractory peripheral mononeuropathy. We included 24 patients who underwent ultrasound-guided cryoneurolysis between June 2018 and July 2022. The daily maximum pain level was recorded using a numerical rating scale before and 1, 3 and 6 months after the procedure. Results: At 1 month, 54.2% of patients reported pain reduction of at least 30%. This percentage was significantly lower at 3 and 6 months (13.8 and 9.1%, respectively). Conclusion: Our results suggest that repeated cryoneurolysis may be a viable treatment for refractory mononeuropathy. Further investigations are needed.

OBJECTIVE: To evaluate the safety and efficacy of computed tomography (CT)-guided microwave ablation combined with vertebral augmentation under real-time temperature monitoring in the treatment of painful osteogenic spinal metastases.
METHODS: This retrospective study included 38 patients with 63 osteogenic metastatic spinal lesions treated using CT-guided microwave ablation and vertebral augmentation under real-time temperature monitoring. Visual analog scale scores, daily morphine consumption, and Oswestry Disability Index scores were used to evaluate efficacy of the treatment.
RESULTS: Microwave ablation combined with vertebral augmentation reduced the mean visual analog scale scores from 6.40 ± 1.90 preoperatively to 3.32 ± 0.96 at 24 h, 2.24 ± 0.91 at 1 week, 1.92 ± 1.32 at 4 weeks, 1.79 ± 1.45 at 12 weeks, and 1.39 ± 1.12 at 24 weeks postoperatively (all p < 0.001). The mean preoperative daily morphine consumption was 108.95 ± 56.41 mg, which decreased to 50.13 ± 25.46 mg at 24 h, 31.18 ± 18.58 mg at 1 week, 22.50 ± 16.63 mg at 4 weeks, 21.71 ± 17.68 mg at 12 weeks, and 17.27 ± 16.82 mg at 24 weeks postoperatively (all p < 0.001). During the follow-up period, the Oswestry Disability Index scores significantly reduced (p < 0.001). Bone cement leakage occurred in 25 vertebral bodies, with an incidence of 39.7% (25/63).
CONCLUSIONS: The results indicate that microwave ablation combined with vertebral augmentation under real-time temperature monitoring is a feasible, effective, and safe treatment for painful osteoblast spinal metastases.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common consequence of cancer treatment that can be persistent and difficult to manage. Dorsal root ganglion stimulation (DRG-S) is a recently introduced but understudied treatment modality. This study explored the effect of DRG-S on pain and symptom burden associated with CIPN.
Patients with CIPN who underwent a DRG-S trial between January 2017 and August 2022 were identified through chart review after IRB approval was obtained. Demographic data, procedure details, pre-and postoperative scores, including the Numerical Rating Scale (NRS) and Edmonton Symptom Assessment System (ESAS), and duration of follow-up were recorded. Statistical analysis included descriptive statistics and paired t-tests to compare pre-and postoperative scores.
Nine patients with an even mix of solid and hematologic malignancies underwent DRG-S trial and had a statistically significant decrease in NRS scores, with a mean reduction of 2.3 in their average pain (p = 0.014), 2.6 in worst pain (p = 0.023), and 2.1 in least pain (p = 0.018). Eight patients (88.9%) underwent permanent DRG-S implantation. Mean NRS scores remained lower than preoperative baselines through the first year of follow-up. Statistically significant reductions were noted at 3 months in average (2.1, p = 0.006) and least pain scores (1.9, p = 0.045), which further decreased after 6-12 months (average: 3.6, p = 0.049; least: 3.4, p = 0.023). Only the pain component of ESAS scores showed a significant reduction with DRG-S (2.0, p = 0.021). All patients endorsed improved sensation, 75% decreased their pain medication usage, and 37.5% reported complete pain relief by 2 years.
Dorsal root ganglion stimulation can be an effective treatment for pain related to CIPN and deserves further investigation.

Background: Although opioids are used first line for cancer pain and commonly for complex noncancer pain, there are risks associated with their use and not effective for all types of pain. There\'s a need to identify and develop clinical practice guidelines for nonopioids for the treatment of refractory pain. Methods: Our study collected information from national clinical practice guidelines for ketamine, lidocaine, and dexmedetomidine with the aim to identify consensus among the different practices. Results: Fifteen institutions nationally participated in the study and only nine of those institutions had guidelines and were permitted by their health system to share them. Of the institutions that participated, 44% had guidelines for ketamine and lidocaine, and only two institutions (22%) had guidelines for ketamine, lidocaine, and dexmedetomidine for refractory pain. There were variations in restriction of the level of care and prescribers, dosing, and determination of efficacy. There were trends of consensus in monitoring for side effects. Conclusion: This study serves as a starting point for a snapshot of the use of ketamine, lidocaine, and dexmedetomidine for refractory pain, but further studies and increased participation of institutions are needed to develop consensus clinical practice guidelines.