The incidence, characteristics, impact and risk factors of post-COVID chronic pain in Thailand: A single-center cross-sectional study.

The COVID-19 pandemic has affected millions of individuals worldwide. Pain has emerged as a significant post-COVID-19 symptom. This study investigated the incidence, characteristics, and risk factors of post-COVID chronic pain (PCCP) in Thailand. A cross-sectional study was conducted in participants who had been infected, including those hospitalized and monitored at home by SARS-CoV-2 from August to September 2021. Data were collected for screening from medical records, and phone interviews were done between 3 to 6 months post-infection. Participants were classified into 1) no-pain, 2) PCCP, 3) chronic pain that has been aggravated by COVID-19, or 4) chronic pain that has not been aggravated by COVID-19. Pain interference and quality of life were evaluated with the Brief Pain Inventory and EuroQol Five Dimensions Five Levels Questionnaire. From 1,019 participants, 90% of the participants had mild infection, assessed by WHO progression scale. The overall incidence of PCCP was 3.2% (95% CI 2.3-4.5), with 2.8% (95% CI 2.0-4.1) in mild infection, 5.2% (95% CI 1.2-14.1) in moderate infection and 8.5% (95% CI 3.4-19.9) in severe infection. Most participants (83.3%) reported pain in the back and lower extremities and were classified as musculoskeletal pain and headache (8.3%). Risk factors associated with PCCP, included female sex (relative risk [RR] 2.2, 95% CI 1.0-4.9) and greater COVID-19 severity (RR 3.5, 95% CI 1.1-11.7). Participants with COVID-19-related exacerbated chronic pain displayed higher pain interferences and lower utility scores than other groups. In conclusion, this study highlights the incidence, features, and risk factors of post-COVID chronic pain (PCCP) in Thailand. It emphasizes the need to monitor and address PCCP, especially in severe cases, among females, and individuals with a history of chronic pain to improve their quality of life in the context of the ongoing COVID-19 pandemic.

The invisible cost of pain management by the current International Classification of Diseases coding system: a study in a tertiary care inpatient setting.

ABSTRACT: The International Classification of Diseases ( ICD ) is applied worldwide for public health data collection among other use cases. However, the current version of the ICD ( ICD-10 ), to which the reimbursement system is linked in many countries, does not represent chronic pain properly. This study aims to compare the ICD-10 with the ICD-11 in hospitalized patients in terms of specificity, clinical utility, and reimbursement for pain management. The medical records of hospitalized patients consulted for pain management at Siriraj Hospital, Thailand, were reviewed, and all pain-related diagnoses were coded into ICD-10 and ICD-11 . The data of 397 patients showed unspecified pain was coded 78% in the ICD-10 and only 0.5% in the ICD-11 version. The difference gap in the proportion of unspecified pain between the 2 versions is wider than in the outpatient setting. The 3 most common codes for ICD-10 were other chronic pain, low back pain, and pain in limb. The 3 most common codes for ICD-11 were chronic cancer pain, chronic peripheral neuropathic pain, and chronic secondary musculoskeletal pain. As in many other countries, no pain-related ICD-10 codes were coded for routine reimbursement. The simulated reimbursement fee remained the same when adding 397 pain-related codings, even if the cost of pain management, such as cost of labor, existed. Compared with the ICD-10 version, the ICD-11 is more specific and makes pain diagnoses more visible. Thus, shifting from ICD-10 to ICD-11 has the potential to improve both the quality of care and the reimbursement for pain management.

Neuropathic pain feature in cancer-induced bone pain: does it matter? a prospective observational study.

Background: Cancer-induced bone pain (CIBP) is considered to have both nociceptive and neuropathic components. However, the prevalence, risk factors, and impact of the neuropathic components are yet poorly understood. Methods: We estimate the prevalence of neuropathic pain (NP) features in patients with CIBP at a tertiary care pain clinic setting using the Douleur Neuropathique 4 questionnaire and evaluate their associated factors and their impact after 4 weeks of treatment using the Brief Pain Inventory questionnaire and the Edmonton Symptom Assessment System. Results: A total of 133 patients were recruited. The estimated prevalence of NP was 30.8% (95% confidence interval: 23.6%-39.1%). Initially, the patients with NP had significantly higher average pain scores (6.00 vs. 5.05, P = 0.006), higher total interference scores (5.84 vs. 4.89, P = 0.033), and symptom distress scores (35.88 vs. 26.52, P = 0.002). After 4 weeks of treatment, patients in both groups reported significantly decreased pain intensity and improved quality of life. However, the patients with NP still reported significantly higher average pain (4.61 vs. 3.58, P = 0.048), trending toward higher total interference scores (3.52 vs. 2.99, P = 0.426), and symptom distress scores (23.30 vs. 20.77, P = 0.524). From multivariate analysis, the independent risk factors for NP were younger age, pain in the extremities, and higher average pain scores. Conclusions: NP are common in patients with CIBP. These conditions negatively affect pain intensity and the patient's quality of life before and after treatment.

Cost-Utility and Cost-Effectiveness Analysis of Spinal Cord Stimulation for Chronic Refractory Pain in the Context of Developing Country.

BACKGROUND: Spinal cord stimulation (SCS) is an effective treatment for chronic refractory pain. The evidence of pain reduction, improvement of function, quality of life, and cost-effectiveness are strong in developed countries. Nevertheless, there is still a lack of economic studies of SCS in the context of low- and middle-income countries. OBJECTIVES: To evaluate the cost-effectiveness and cost-utility of additional SCS to conventional management (CMM) in patients with chronic refractory pain in Thailand. STUDY DESIGN: Prospective observational study. SETTING: The pain clinic at Siriraj Hospital, a tertiary care center in Thailand. METHODS: This study recruited patients undergoing SCS implants due to refractory pain to CMM from varieties of conditions and followed up to 36 months. The clinical outcomes, quality of life, and costs of treatment were collected before and after SCS implantation. A decision tree and Markov model were developed to estimate the total lifetime costs and health benefits of SCS using a societal perspective. The results were presented as an incremental cost-utility ratio (ICUR) in 2021 Thai Baht (THB) per quality-adjusted life year (QALY) gained and an incremental cost-effective ratio (ICER) in 2021 THB per numeric rating pain score (NRS) reduction. RESULTS: Twenty-nine patients who underwent SCS implantation reported pain intensity and increased utility at every point in time. Compared to pre-implantation, the QALY gained in both rechargeable and non-rechargeable SCS was 2.13 QALYs. The economic analysis showed the ICUR in the rechargeable and non-rechargeable SCS + CMM group was 660,106.96, and 620,120.59 THB/QALY gained, respectively, which was higher than Thais' willingness-to-pay (WTP) threshold at 160,000 THB/QALY gained. Pain score reduction was 2.49/10 at the 3-year point, and the ICER was 496,932.08 and 337,341.77 THB/NRS reduction for rechargeable and non-rechargeable SCS, respectively. LIMITATIONS: As this is a single-center prospective cohort study, the results might be subject to selection bias and may not truly represent all patients from a developing country. The cost-effectiveness results should also be carefully interpreted for generalizability. CONCLUSION: Spinal cord stimulation is effective in pain control and improves the quality of life for patients with chronic refractory pain. However, the ICUR of SCS is above the WTP, leading to the interpretation that SCS is still not a cost-effective treatment in the current context in Thailand.

Reliability and responsivity of pain intensity scales in individuals with chronic pain.

ABSTRACT: Prior research supports the validity and short-term test-retest stability of 4 commonly used scales for assessing pain intensity (Visual Analogue Scale [VAS], 6-point Verbal Rating Scale [VRS-6], Numerical Rating Scale [NRS-11], and Face Pain Scale-Revised [FPS-R]). However, the relative stability and ability of these measures to detect changes in pain intensity over longer time periods have not yet been examined, although knowledge regarding these psychometric issues is important for selecting from among these measures. To address this knowledge gap, we administered these scales assessing worst and average pain intensity to 250 chronic pain outpatients on 2 occasions, a little over 6 weeks apart on average. All 4 scales were found to be valid for detecting decreases in pain, and the VAS, NRS-11, and FPS-R evidenced the most validity for detecting increases in pain. The NRS-11 and VAS evidenced better test-retest stability than the VRS-6 and FPS-R. Age affected the ability of the VRS-6 for detecting improvement in worst pain, as well as the ability of the VAS for detecting worsening in both worst and average pain. However, the psychometric properties of the scales were not influenced by education level. Overall, the NRS-11 emerged as showing the most sensitivity and stability. The FPS-R seems to be a good second choice to consider for samples of individuals who might have difficulty understanding or using the NRS-11.

The Effectiveness of Cancer Pain Management in a Tertiary Hospital Outpatient Pain Clinic in Thailand: A Prospective Observational Study.

Objectives: The objective was to examine the effectiveness of the updated approach. Methods: With IRB approval, outpatients with cancer were enrolled from January to December 2018. Assessments were recorded at baseline and three consecutive visits (BL, FU1, FU2, and FU3), including Numerical Rating Scale (NRS), the Brief Pain Inventory (BPI), the Edmonton Symptom Assessment System (ESAS), side effects, and analgesic use. The primary outcome was a favorable response, defined as an NRS decrease more than 30% or NRS <4. Secondary outcomes included trends over time in BPI, ESAS, side effects, and analgesic use. Pain response predictors at FU3 were analyzed using logistic regression. Results: Among 150 patients, 72 (48%) completed follow-ups. Of these, 61% achieved a favorable response at FU3. Pain interference diminished at all visits relative to baseline (p < 0.05). Median morphine equivalent daily dosage (MEDD) at BL was 20 mg/day, with a statistically significant, but clinically modest increase to 26.4 mg/day at FU3. Radiation therapy during pain care was a predictor of pain responders. Conclusion: The current Siriraj multidisciplinary approach provided effective relief of pain and stabilization of other cancer-related symptoms. Radiation therapy during pain care can be used to predict pain outcomes. Ongoing improvement domains were identified and considered in the context of cultural, economic, and geographic factors.

International Association for the Study of Pain Presidential Task Force on Cannabis and Cannabinoid Analgesia: research agenda on the use of cannabinoids, cannabis, and cannabis-based medicines for pain management.

ABSTRACT: The President of the International Association for the Study of Pain established a task force on cannabis and cannabinoid analgesia to systematically examine the evidence on (1) analgesic pharmacology of cannabinoids and preclinical evidence on their efficacy in animal models of injury-related or pathological persistent pain; (2) the clinical efficacy of cannabis, cannabinoids, and cannabis-based medicines for pain; (3) harms related to long-term use of cannabinoids; as well as (4) societal issues and policy implications related to the use of these compounds for pain management. Here, we summarize key knowledge gaps identified in the task force outputs and propose a research agenda for generating high-quality evidence on the topic. The systematic assessment of preclinical and clinical literature identified gaps in rigor of study design and reporting across the translational spectrum. We provide recommendations to improve the quality, rigor, transparency, and reproducibility of preclinical and clinical research on cannabis and cannabinoids for pain, as well as for the conduct of systematic reviews on the topic. Gaps related to comprehensive understanding of the endocannabinoid system and cannabinoid pharmacology, including pharmacokinetics and drug formulation aspects, are discussed. We outline key areas where high-quality clinical trials with cannabinoids are needed. Remaining important questions about long-term and short-term safety of cannabis and cannabinoids are emphasized. Finally, regulatory, societal, and policy challenges associated with medicinal and nonmedicinal use of cannabis are highlighted, with recommendations for improving patient safety and reducing societal harms in the context of pain management.

Persistent Post-Mastectomy Pain: The Impact of Regional Anesthesia Among Patients with High vs Low Baseline Catastrophizing.

BACKGROUND: Persistent post-mastectomy pain (PPMP) varies both in its severity and impact, with psychosocial factors such as catastrophizing conferring greater risk. Preoperative regional anesthesia (RA) is an important nonopioid therapy, but with variable success at preventing PPMP in previous reports. We previously reported that RA was associated with lower acute post-mastectomy pain and opioid use, but more prominently among patients with higher baseline catastrophizing. The current longitudinal investigation at 3, 6, and 12 months postop aimed to detect differential long-term impact of RA on PPMP among patients with high vs low catastrophizing. METHODS: In this prospective observational study, patients (n = 123) completed preoperative psychosocial assessment and underwent mastectomy either with (n = 56) or without (n = 67) preoperative RA. Generalized estimating equation (GEE) regression analysis assessed impact of baseline catastrophizing, RA, and their interaction, on the primary outcome of pain severity index, as well as secondary outcomes including cognitive and emotional impact of pain, and persistent opioid use. RESULTS: We observed a significant interaction between the effect of catastrophizing and RA on PPMP. Specifically, RA was associated with reduced pain severity and pain impact 3, 6, and 12 months postoperatively, but only among those with high baseline catastrophizing scores. In addition, both RA and lower catastrophizing scores were associated with lower incidence of persistent opioid use. CONCLUSIONS: The efficacy of therapies to prevent PPMP may be importantly influenced by pain-modulatory psychosocial characteristics. These findings underscore the importance of considering individual patient factors when applying preventive treatments, and of including their assessment in future trials.

Comparing the ICD-11 chronic pain classification with ICD-10: how can the new coding system make chronic pain visible? A study in a tertiary care pain clinic setting.

ABSTRACT: Pain is a frequent reason for patients to ask for medical services. However, systematic information about the extent and impact of pain, especially in developing countries, has not been available up to now. We evaluated whether the 11th edition of the International Statistical Classification of Diseases and Related Health Problems (ICD) can fill this gap by coding all electronic out-patient medical records of the pain clinic at Siriraj Hospital in Thailand in 2019 (8714 visits), using the ICD-10 and ICD-11 browsers referenced on the WHO websites. The 3 most frequent pain-related codes in ICD-10 were R52.2 "other chronic pain" (29%), M54.5 "low back pain" (18%), and M79.6 "pain in limb" (13%). In ICD-11, the 3 most frequent codes were MG30.31 "chronic secondary musculoskeletal pain associated with structural changes" (28%), MG30.51 "chronic peripheral neuropathic pain" (26%), and MG30.10 "chronic cancer pain" (23%). Thus, using the currently valid ICD-10 system, roughly one-third of patient encounters were coded as "other chronic pain," and the next 2 were specifying the pain region rather than any underlying cause. By contrast, ICD-11 coding of the same patients identified underlying causes (bones and joints, somatosensory nervous system, cancer, or surgery), which provide guidance towards differential patient management. In our pain clinic, most patients suffered from chronic cancer pain, chronic neuropathic pain, and chronic secondary musculoskeletal pain, which were poorly defined or nonexistent in the current ICD-10 coding system. Compared with the ICD-10, the ICD-11 provides more detailed diagnostic categories and is more informative for clinical use, research, and resource allocation for pain-related conditions.

Benefit of regional anaesthesia on postoperative pain following mastectomy: the influence of catastrophising.

BACKGROUND: Previous studies suggest that truncal regional anaesthesia (TRA), including techniques such as paravertebral block, may contribute significantly to analgesia after mastectomy. However, the severity and impact of postoperative pain varies markedly amongst individuals, making the identification of patients who would benefit most from TRA a potentially important step toward personalised perioperative care. METHODS: In this prospective observational study, mastectomy patients (n=122) were recruited and systematically assessed for psychosocial characteristics including pain catastrophising before surgery, and either received preoperative TRA (n=57) or no block (n=65). RESULTS: Age, baseline pain, and psychosocial traits did not differ between these groups. TRA was associated with lower overall pain scores and opioid consumption perioperatively, with a larger proportion of patients without block (50% vs 28%) reporting moderate-severe pain (more than three/10) on the day of surgery. Mixed model analysis of variance revealed a significant interaction between catastrophising and TRA, such that amongst patients with high baseline catastrophising, TRA was associated with substantially lower pain severity score (58% lower), while amongst patients with low baseline catastrophising, TRA was associated with only 18% lower pain severity. At 2 weeks, this interaction between baseline catastrophising and TRA was also observed when examining surgical pain burden, with higher baseline catastrophising patients who had received TRA reporting lower pain and less frequent opioid use (40% vs 70% of patients). CONCLUSIONS: TRA provided immediate analgesic benefit for patients undergoing mastectomy on the day of surgery, but this effect appeared more pronounced and sustained amongst patients with higher baseline catastrophising. CLINICAL TRIAL REGISTRATION: NCT02329574.

The ultrasound-guided proximal intercostal block: anatomical study and clinical correlation to analgesia for breast surgery.

BACKGROUND: The ultrasound-guided proximal intercostal block (PICB) is performed at the proximal intercostal space (ICS) between the internal intercostal membrane (IIM) and the endothoracic fascia/parietal pleura (EFPP) complex. Injectate spread may follow several routes and allow for multilevel trunk analgesia. The goal of this study was to examine the anatomical spread of large-volume PICB injections and its relevance to breast surgery analgesia. METHODS: Fifteen two-level PICBs were performed in ten soft-embalmed cadavers. Radiographic contrast mixed with methylene blue was injected at the 2nd(15 ml) and 4th(25 ml) ICS, respectively. Fluoroscopy and dissection were performed to examine the injectate spread. Additionally, the medical records of 12 patients who had PICB for breast surgery were reviewed for documented dermatomal levels of clinical hypoesthesia. The records of twelve matched patients who had the same operations without PICB were reviewed to compare analgesia and opioid consumption. RESULTS: Median contrast/dye spread was 4 (2-8) and 3 (2-5) vertebral segments by fluoroscopy and dissection respectively. Dissection revealed injectate spread to the adjacent paravertebral space, T3 (60%) and T5 (27%), and cranio-caudal spread along the endothoracic fascia (80%). Clinically, the median documented area of hypoesthesia was 5 (4-7) dermatomes with 100 and 92% of the injections covering adjacent T3 and T5 dermatomes, respectively. The patients with PICB had significantly lower perioperative opioid consumption and trend towards lower pain scores. CONCLUSIONS: In this anatomical study, PICB at the 2nd and 4th ICS produced lateral spread along the corresponding intercostal space, medial spread to the adjacent paravertebral/epidural space and cranio-caudal spread along the endothoracic fascial plane. Clinically, combined PICBs at the same levels resulted in consistent segmental chest wall analgesia and reduction in perioperative opioid consumption after breast surgery. The incomplete overlap between paravertebral spread in the anatomical study and area of hypoesthesia in our clinical findings, suggests that additional non-paravertebral routes of injectate distribution, such as the endothoracic fascial plane, may play important clinical role in the multi-level coverage provided by this block technique.

Preoperative Psychosocial and Psychophysical Phenotypes as Predictors of Acute Pain Outcomes After Breast Surgery.

The severity and impact of acute pain after breast surgery varies markedly among individuals, underlining the importance of comprehensively identifying specific risk factors, including psychosocial and psychophysical traits. In this prospective observational study, women (n = 234) undergoing breast-conserving surgery, mastectomy, or mastectomy with reconstruction completed a brief bedside quantitative sensory testing battery, along with measures of psychosocial characteristics. Postoperative pain severity, impact, and opioid use at 2 weeks were assessed using Brief Pain Inventory and procedure-specific breast cancer pain questionnaires. Moderate-severe average pain (>3/10) was reported by 29% of patients at 2 weeks. Regression analysis of pain outcomes revealed that pain severity was independently predicted by axillary dissection, pre-surgical pain, temporal summation of pain (TSP), (-)positive affect, and behavioral coping style. Pain impact was predicted by age, education, axillary dissection, reconstruction, but also by negative affect and depression scores. Lastly, opioid use was predicted by age, education, axillary dissection, reconstruction, TSP, and reinterpreting coping style. Our findings suggest that, individuals with certain phenotypic characteristics, including high TSP and negative affect, may be at greater risk of significant pain and continued opioid use at 2 weeks after surgery, independent of known surgical risk factors. PERSPECTIVE: We measured differences in the psychosocial and psychophysical processing of pain amongst patients before breast surgery using simple validated questionnaires and brief quantitative sensory testing. Independent of younger age and procedural extent (axillary surgery and reconstruction), affect and greater temporal summation of pain predicted acute postoperative pain and opioid use.

Chronic Pain After Breast Surgery: A Prospective, Observational Study.

BACKGROUND: Chronic pain is an important complication of breast surgery, estimated to affect 20-30% of patients. We prospectively examined surgical, demographic, and psychosocial factors associated with chronic pain 6 months after breast surgery. METHODS: Patients undergoing breast surgery for benign and malignant disease preoperatively completed validated questionnaires to assess baseline pain and psychosocial characteristics. Pain at 6 months was quantified as the Pain Burden Index (PBI), which encompasses pain locations, severity, and frequency. Surgical type was categorized as breast-conserving surgery (BCS), mastectomy, and mastectomy with reconstruction; axillary procedure was categorized as no axillary surgery, sentinel lymph node biopsy (SLNB), and axillary dissection. PBI was compared between groups using one-way analysis of variance (ANOVA) or Kruskal-Wallis ANOVA, and the relationship between baseline demographic and psychosocial factors and PBI was assessed using Spearman's Rank Correlation. p < 0.05 was considered significant. RESULTS: PBI was variable amongst patients reporting this endpoint (n = 216) at 6 months, but no difference was found between primary breast surgical types (BCS, mastectomy, and mastectomy with reconstruction) or with surgical duration. However, axillary dissection was associated with higher PBI than SLNB and no axillary procedure (p < 0.001). Younger age (< 0.001) and higher BMI (p = 0.010), as well as higher preoperative anxiety (p = 0.017), depression (p < 0.001), and catastrophizing scores (p = 0.005) correlated with higher 6-month PBI. CONCLUSIONS: Amongst surgical variables, only axillary dissection was associated with greater pain at 6 months after surgery. Patient characteristics that were associated with higher PBI included lower age and higher BMI, as well as higher baseline anxiety, depression, and catastrophizing.

Efficacy and factors determining the outcome of dorsal root entry zone lesioning procedure (DREZotomy) in the treatment of intractable pain syndrome.

BACKGROUND: Chronic pain is a disabling condition that adversely affects patient quality of life. The dorsal root entry zone lesioning procedure (DREZotomy) is a modality used to treat intractable pain caused by insults to neural structures. This study aimed to investigate the efficacy of and the factors that determine the outcome of microsurgical DREZotomy (MDT). METHOD: All consecutive patients who underwent MDT for treatment of intractable pain during September 2008 to December 2016 were enrolled. Demographic data, clinical characteristics, intraoperative findings, and postoperative outcomes were analyzed. RESULTS: The 40 included patients underwent MDT for relief of intractable pain caused by 27 brachial plexus injuries (BPIs), 6 spinal cord injuries, 3 neoplasms, and 4 other causes. A significant reduction in pain was observed post-MDT for both average (p < 0.001) and maximal pain (p < 0.001). Favorable outcome (≥50% pain reduction) was observed in 67.5% of patients, with the best outcome in BPI-related pain. In multivariate analysis, injury of the spinal nerve root (root avulsion or injury) was significantly associated with good average pain relief (OR, 5.8; 95% CI, 1.2-27.5; p = 0.026) and pain freedom (OR, 5.0; 95% CI, 1.12-22.30; p = 0.035). Electrical pain (OR, 6.49; 95% CI, 1.20-35.19; p = 0.030) and lower number of painful dermatomes (OR, 1.30; 95% CI, 1.01-1.67; p = 0.039) were significantly associated with good maximal pain relief. CONCLUSIONS: MDT is an effective procedure for treatment of intractable pain in well-selected patients, particularly in cases with brachial plexus avulsion pain. Injury of the spinal nerve root (brachial plexus avulsion and cauda equina injury) was associated with good average pain relief and pain freedom, and electrical pain and lower number of painful dermatomes were associated with good maximal pain relief. The results are useful in the selection of candidates for DREZotomy and prediction of surgical outcome.

Upper Antero-Medial Thigh as an Alternative Site for Implantation of Intrathecal Pumps: A Case Series.

INTRODUCTION: Neuraxial drug delivery via intrathecal drug delivery systems (IDDS) is becoming an increasingly common mode of treating intractable cancer-related pain, chronic pain, or severe spasticity. An implanted infusion pump delivers medication into the intrathecal (subarachnoid) space via a thin catheter. These pumps are commonly placed in the anterior abdominal wall. Certain conditions may render it difficult or unsafe for an IDDS to be implanted at the traditional site; thus, alternative sites have been explored. We report on the use of the upper antero-medial thigh as a safe alternative site for this purpose. METHODS AND MATERIALS: Nine patients between 22 and 69 years of age underwent placement of an IDDS infusion pump in the upper antero-medial aspect of one thigh. In each patient, the anterior abdominal wall was precluded for implantation due to various reasons, such as extensive abdominal scar tissue from previous surgeries, placement of feeding tubes and ostomies, large ventral hernia or metastatic masses protruding from the abdomen. RESULTS: Nine patients, with ages ranging from 22 to 69 years old, had IDDS implantation in the upper thigh. The first patient experienced wound dehiscence (antero-lateral location) and after explantation, another pump was placed successfully in the opposite thigh (antero-medial location). One patient has had pump replacement due to end-of-battery life. She also needed an unrelated catheter revision. Seven patients have expired from their disease progression after living for an average of 142.7 days (range 50 days to 354 days) while two patients continue to experience relief from pain and spasticity years later (see Table 1). No neurovascular damage, infections, or other complications occurred in our series. CONCLUSION: The upper antero-medial thigh is a safe alternative to the anterior abdominal wall for implantation of an IDDS.

Brachial Plexus Block for Cancer-Related Pain: A Case Series.

Neoplastic brachial plexopathy (NBP) is caused by a cancerous infiltration into the brachial plexus, presenting often as severe pain in the affected upper extremity. Such pain can be resistant to medical treatment. Invasive interventions such as brachial plexus neurolysis with phenol or cordotomy may result in severe complications including permanent neurological damage and death. Continuous brachial plexus and paravertebral block with local anesthetic have been reported to successfully control pain from NBP, but these techniques are logistically challenging and frequently have catheter-related complications. We report a series of patients who received single-shot brachial plexus blocks with a mixture of local anesthetic and corticosteroid (bupivacaine 0.25% with methyl-prednisolone 20-120 mg) for the treatment of refractory cancer-related pain in the brachial plexus territory, mostly from NBP. Theoretically, such blocks could provide immediate analgesia from the local anesthetic and a longer-lasting analgesia from the slow-release steroids. Responders reported a sustained decrease in their pain (lasting from 2 weeks to 10 months), a significant decrease in their opioid and non-opioid (ketamine, gabapentin) consumption, overall satisfaction with the block, and unchanged or improved function of their limb. The ideal candidate for this procedure is a patient who has pain that is predominantly neuropathic from a lesion within the brachial plexus and with anatomy amenable to ultrasound-guided nerve block. Our case series suggests that, in the appropriately selected patient, this technique can safely and effectively alleviate pain from NBP. The procedure is simple, spares limb function, and can be diagnostic, predicting response to more complex procedures. To the best of our knowledge, this is the first report using this technique for NBP.

Harlequin Syndrome Following Implantation of Intrathecal Pumps: A Case Series.

OBJECTIVE: Harlequin syndrome (HS) is a condition that has been associated with one-sided sympathetic denervation of the face, characterized by contralateral hemifacial flushing and relative hyperhidrosis. Case series associate HS with conditions and procedures, including neuraxial anesthesia, that disrupt unilateral facial sympathetic innervation. However, to the best of our knowledge, this is the first series of HS following implantation of an intrathecal drug delivery system. CASE SERIES: A 37-year-old and 58-year-old female patients with intractable pain from metastatic cancer were scheduled for placement of an intrathecal pump drug delivery system. Thirty minutes after a mixture of hydromorphone, bupivacaine, and clonidine was initiated through the intrathecal pump, both patients developed well-demarcated skin flushing, confined to one side of their face. Patients were not in distress, and physical examination revealed neither focal neurological deficits nor ocular involvement. Postprocedure thoracolumbar spine magnetic resonance imaging (MRI) was done in the first patient and showed no evidence of neuraxial bleeding or spinal cord compression. The flushing gradually faded and eventually disappeared without any untoward effects. CONCLUSION: HS is a condition associated with one-sided sympathetic denervation of the face that can occur after intrathecal pump implantation. An understanding of the pathophysiology of this condition and reassurance are vital factors for successful management of this condition.