Long-term pain outcomes after serial lidocaine infusion in participants with recent onset of peripheral neuropathic pain: A pilot double-blind, randomized, placebo-controlled trial.

BACKGROUND: This study investigated the outcomes up to 12 weeks after serial lidocaine infusion for early-onset peripheral neuropathic pain. METHODS: This pilot double-blind, randomized, 2-arm placebo-controlled trial recruited 50 participants with onset of peripheral neuropathic pain within the past 6 months and randomized them to either receive lidocaine (3 mg/kg) in normal saline (50 mL) intravenous infusion over 1 hour (lidocaine group) once a week for 4 weeks or 50 mL of normal saline infusion (placebo group) once a week for 4 weeks. Twenty-nine participants completed the protocol; 15 participants were assigned to the lidocaine group and 14 to the placebo group. The outcomes were pain intensity assessed using a numerical rating scale (NRS), quality of life assessed using EuroQol-Five Dimensions-Five Levels questionnaire (EQ-5D-5L), psychological function using the Thai version of the 21-item Depression Anxiety Stress Scales (DASS-21), pain medication use, and adverse effects, all assessed at baseline (BL) and again at 4, 8, and 12 weeks following randomization. RESULTS: The reported tramadol use at 8 and 12 weeks following the first infusion was significantly lower in the lidocaine group (P = .023). No other significant between-group differences were observed at any time point or for any other outcome, and no serious adverse events were observed. CONCLUSION: Multiple lidocaine infusions of 3 mg/kg once a week for 4 weeks in participants with recent onset of peripheral neuropathic pain demonstrated no significant benefits in pain intensity, quality of life, or psychological outcomes. At most, this treatment may result in less tramadol use.

Retrograde Epidural Spinal Cord Stimulation for the Treatment of Intractable Neuropathic Pain Following Spinal Cord and Cauda Equina Injuries: A Case Report and Literature Review.

Spinal cord stimulation (SCS) offers an alternative treatment for refractory pain resulting from various etiologies. Generally, SCS electrodes are inserted in an anterograde fashion, moving from caudal to rostral direction. However, there are instances where anterograde placement is unfeasible due to technical limitations. We present the use of retrograde surgical electrode placement in SCS for a patient with extensive epidural fibrosis at the site intended for electrode insertion. A 48-year-old female suffering from refractory neuropathic pain caused from injuries to the conus medullaris and cauda equina opted for SCS. During the SCS trial procedure, challenges emerged when attempting percutaneous electrode insertion at the site of a prior T12 laminectomy. However, the trial stimulation resulted in significant pain relief. For the permanent placement of the stimulator, utilizing a surgical electrode centered at T11 vertebral level, a considerable amount of epidural fibrosis was encountered at the entry of the spine, particularly at the T12 vertebral level. To avoid dural injury and ensure accurate electrode positioning, a retrograde technique for surgical electrode was employed via partial laminectomies at the T9-T10 level. The final electrode positioning was in accordance with the preoperative plan, well-centered at the T11 vertebral level. The patient experienced sustained relief from neuropathic pain over the long term. Retrograde epidural SCS is a suitable option for cases characterized by extensive epidural fibrosis resulting from a previous spinal surgery or when the anterograde placement of the electrode is unattainable due to aberrant vertebral anatomy.

Transcranial direct current stimulation for spinal cord injury-associated neuropathic pain.

Several types of pain occur following spinal cord injury (SCI); however, neuropathic pain (NP) is one of the most intractable. Invasive and non-invasive brain stimulation techniques have been studied in clinical trials to treat chronic NP following SCI. The evidence for invasive stimulation including motor cortex and deep brain stimulation via the use of implanted electrodes to reduce SCI-related NP remains limited, due to the small scale of existing studies. The lower risk of complications associated with non-invasive stimulation, including transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), provide potentially attractive alternative central neuromodulation techniques. Compared to rTMS, tDCS is technically easier to apply, more affordable, available, and potentially feasible for home use. Accordingly, several new studies have investigated the efficacy of tDCS to treat NP after SCI. In this review, articles relating to the mechanisms, clinical efficacy and safety of tDCS on SCI-related NP were searched from inception to December 2019. Six clinical trials, including five randomized placebo-controlled trials and one prospective controlled trial, were included for evidence specific to the efficacy of tDCS for treating SCI-related NP. The mechanisms of action of tDCS are complex and not fully understood. Several factors including stimulation parameters and individual patient characteristics may affect the efficacy of tDCS intervention. Current evidence to support the efficacy of utilizing tDCS for relieving chronic NP after SCI remains limited. Further strong evidence is needed to confirm the efficacy of tDCS intervention for treating SCI-related NP.

Psychometric Validity and Reliability of the Thai Version of the Neuropathic Pain Symptom Inventory.

OBJECTIVE: The aim of this study was to evaluate validity and reliability of the Thai version of the Neuropathic Pain Symptom Inventory (NPSI-T) in Thai patients with neuropathic pain. Although the Thai version of Neuropathic Pain Symptom Inventory (NPSI-T) has been linguistically validated, the tool has to be psychometrically validated before applying to neuropathic pain patients in daily practice. MATERIAL AND METHOD: Forty Thai patients with diagnosis of neuropathic pain were enrolled to the study and were evaluated by visual analog scale (VAS), the Thai version of Neuropathic Pain Diagnostic Questionnaire (DN4-T) and NPSI-T questionnaires. Four hours later the patients were asked to perform retest NPSI-T and to evaluate the understanding of each NPSI-T question. RESULTS: The total score of NPSI-T questionnaire was statistically correlated to visual analog scale (VAS) (Spearman's correlation coefficient = 0.599, p < 0.001) and neuropathic pain diagnostic questionnaire (DN4-T) (Spearman's correlation coefficient = 0.695, p < 0.001). The reliability was determined by Intraclass correlation coefficient (ICC), an excellent interobserver agreement (ICC > 0.8) and good agreement (ICC 0.6-0.8) were presented in 30% and 70% of the questionnaire, respectively. CONCLUSION: The study demonstrated validity and reliability of the NPSI-T for assessing the neuropathic pain in Thai patients.

Effective Pain Management for Inpatients at Siriraj Hospital: A Retrospective Study.

BACKGROUND AND OBJECTIVE: The prevalence of severe cancer and non-cancer pain among in patients has been reported at rates ranging from 15% to 36%. We examined the effectiveness of the pain management provided to inpatients by the Siriraj Pain Clinic. MATERIAL AND METHOD: A retrospective chart review was conducted among inpatients who had consulted the clinic between January 2013 and December 2014. Patients with a numeric pain rating scale (NRS) 4 on the day of consultation, those discharged within seven days, and postoperative patients were excluded. Successful pain control was defined as NRS ≤ 4 within seven days of the initial consultation. RESULTS: We identified 352 eligible patients, of which 231 (65.4%) had cancer pain. Only 42.6% achieved successful pain control. An absence of psychological problems (odds ratio (OR) 2.1, 95% confidence interval (CI) 1.1-4.2; p = 0.010); an initial NRS < 7 (OR 1.9, 95% CI 1.2-3.0; p = 0.008); the use of either a non-steroidal anti-inflammatory drugs (NSAIDs) or a Coxibs (OR 2.3, 95% CI 1.3-3.9; p = 0.017), and abdominal pain (OR 2.7, 95% CI 1.5-4.7; p =0.008) were factors associated with successful pain control. CONCLUSION: Adequate pain control was achieved in less than half of the inpatients in our institution. Psychological disturbance and severe pain predicted unsatisfactory pain control.