Effect of Nonsurgical Spinal Decompression on Intensity of Pain and Herniated Disc Volume in Subacute Lumbar Herniated Disc.

Objective: Nonsurgical spinal decompression therapy (NSDT) is a conservative treatment for the lumbosacral herniated intervertebral disc (L-HIVD). This study aimed to evaluate the clinical effectiveness of the NSDT and change in disc volume through magnetic resonance imaging (MRI) in subacute L-HIVD. Methods: Sixty patients with subacute L-HIVD were randomized into either the decompression group (group D, n = 30) or the nondecompression group (group N, n = 30). In group D, NSDT was performed ten times in eight weeks. In group N, pseudodecompression therapy (no force) was performed with the same protocol. Lower back and lower leg pain intensities and functional improvements were measured by the visual analog scale and the Korean Oswestry Disability Index (K-ODI). The change in the lumbosacral disc herniation index (HI) was evaluated through a follow-up MRI three months after the therapy. Results: The lower leg pain intensity in group D was lower than that in group N at two months (p=0.028). Additionally, there were significantly lower K-ODI scores in group D at two and three months (p=0.023, 0.019) than in group N. The change in HI after the therapy was -27.6 ± 27.5 (%) in group D and -7.1 ± 24.9 (%) in group N, with a significant difference (p=0.017). Approximately 26.9% of patients in group D and no patients in group N showed over 50% reduction in HI (p=0.031). Conclusion: NSDT may be a suitable treatment option for conservative treatment of subacute L-HIVD.

Pulsed Radiofrequency Ablation of the C2 Dorsal Root Ganglion Using a Posterior Approach for Treating Cervicogenic Headache: A Retrospective Chart Review.

OBJECTIVE: To evaluate the efficacy and complications of C2 dorsal root ganglion (DRG) pulsed radiofrequency ablation (RFA) for cervicogenic headache (CEH) and to identify factors related to the outcome of the procedure in this retrospective analysis. BACKGROUND: Although conventional high-temperature C2 DRG RFA was effective in patients with CEH in previous studies, the effect of pulsed RFA on C2 DRG in cases of CEH has not yet been evaluated. METHODS: We examined the electronic medical records of consecutive patients who underwent C2 DRG block for CEH from January 2012 to May 2018 at a pain center. Consequent C2 DRG pulsed RFA was performed for patients in whom the headache recurred after an initial period of relief 24 hours after the C2 DRG block. A successful outcome was defined as at least 50% pain relief at 6 months after C2 DRG pulsed RFA. We also examined variables associated with the outcome and prognostic factors of CEH. RESULTS: Fluoroscopy-guided C2 DRG block was performed in 114 patients with CEH. Forty-five patients received C2 DRG pulsed RFA and 40.0% among them (18/45, success group) had ≥50% pain relief after 6 months. There were no post-procedure complications throughout the study period. Significantly more patients in the success group than in the failure group had a definite positive response (≥50% pain relief) to a previous C2 DRG block (P < .001). CONCLUSION: C2 DRG pulsed RFA may be an effective treatment for patients with CEH, particularly for patients who have previously experienced definite pain reduction after C2 DRG block. However, the limitations of our study design and small number of patients preclude firm conclusions.

A Retrospective Study to Evaluate the Effect of Concentration of Hypertonic Saline on Efficacy and Safety of Epidural Adhesiolysis.

BACKGROUND: Percutaneous epidural adhesiolysis (PEA) is a minimally invasive procedure that is performed to relieve low back and/or lower limb pain secondary to adhesions or scarring in the epidural space that is refractory to conservative treatment. The optimal concentration of hypertonic saline might be an important factor in the safety and efficacy of PEA. We evaluated differences in the efficacy and safety of 2 concentrations of hypertonic saline (5% and 10%) used in lumbar PEA at our institutions in a retrospective study. METHODS: Patients who received lumbar PEA between January 2009 and June 2014 at either of 2 large civilian teaching institutions in South Korea were assigned to the 5% or 10% groups according to the osmolality of saline. The primary outcome of this study was the difference in change in the 11-point numerical rating scale (NRS) scores of low back and leg pain from baseline to 6 months after PEA between patients in the 2 groups. The number of additional epidural injections, patients' satisfaction with PEA, and any complications that occurred within 6 months after PEA were reviewed. RESULTS: This study included 543 patients (5% group, 333; 10% group, 210). Post-PEA NRS pain scores were significantly lower compared with those at baseline in both groups; however, there were no significant differences between the 2 groups at 6 months or any time point after PEA with regard to any of the clinical characteristics, except infusion-related pain, which exhibited borderline significance for greater scores in the 10% group compared with those in the 5% group (P = .041). Multivariable linear regression analysis with adjustments for covariates, including the number of additional epidural injections, revealed no significant association between patient group and the decrease in NRS pain scores at 6 months of follow-up. Transient adverse events related to PEA were recorded in 3 patients (10% group, 2; 5% group, 1). CONCLUSIONS: In PEA, 5% hypertonic saline exhibited similar positive outcomes after 6 months of follow-up as 10% hypertonic saline, with less infusion-related pain. This result suggests that infusion of 5% hypertonic saline may be considered as an alternative to 10% hypertonic saline in lumbar PEA. Further prospective randomized studies are required to better appreciate the outcome with regard to the use of different concentrations of hypertonic saline for PEA.

The Therapeutic Effect of Vitamin C in an Animal Model of Complex Regional Pain Syndrome Produced by Prolonged Hindpaw Ischemia-Reperfusion in Rats.

Objectives: It is known that increased free radicals from oxidative stress are one of the major causes of complex regional pain syndrome (CRPS). In this study, we tested the hypothesis that vitamin C has a dose-related treatment effect in a chronic post-ischemic pain (CPIP) model. Methods: A total of 49 male rats weighing 250 to 350 g were used. The 4 treatment groups were control (no medication), group 1.0 (administration of 1 mg/day for vitamin C for 5 days), group 2.5 (administration of 2.5 mg/day vitamin C for 5 days), and group 7.5 (administration of 7.5 mg/day vitamin C for 5 days). The 50% mechanical withdrawal threshold and total blood antioxidant status (TAS) were measured before and after administration of vitamin C. Results: Twenty-eight CPIP model rats were generated from 49 rats. Seven rats were randomly allocated to each group. The 50% mechanical withdrawal threshold of group 2.5 (after the administration of vitamin C) was higher than that of the control group and group 1.0 (P < 0.05). At 1 day of the administration of vitamin C, the 50% mechanical withdrawal threshold of group 1.0 was higher than that of the control group and the blood levels of TAS in groups 2.5 and 7.5 were higher than that in control group (P < 0.05). Twelve days after the administration of vitamin C, the blood levels of TAS in groups 2.5 and 7.5 were lower than that of the control group (P < 0.05). Discussion: The administration of a proper dose of vitamin C can reduce oxidative stress, increase antioxidants, and recover the threshold for mechanical allodynia in the CPIP model.

Does improvement in epidurography following percutaneous epidural neuroplasty correspond to patient outcome?

OBJECTIVE: The positive effects of percutaneous epidural neuroplasty (PEN) likely result from elimination of fibrous tissue. However, a direct link between epidural adhesions and pain symptoms is debatable. We tested the hypothesis that epidurographic improvements correspond to improved patient outcome. METHODS: In this prospective study, patients with a filling defect on initial epidurography underwent PEN. Two weeks later, contrast agent distribution around the target area was assessed with repeat epidurography. A successful treatment was defined as over a 50% reduction in visual analog scale (VAS) score 2 weeks postprocedure. The demographic data, history of lumbar spine operation, target nerve, diagnosis, VAS scores, degree of epidurographic improvement, and patient satisfaction were compared between the successful treatment group (Group I) and unsuccessful treatment group (Group II). RESULTS: Seventy-nine patients were included. Epidurographic findings improved in 67.1% of patients 2 weeks after the procedure. Following PEN, the mean VAS scores of all patients were significantly decreased at 2 weeks (4.12 ± 2.34), 1 month (3.56 ± 2.30), 3 months (3.84 ± 2.45), and 6 months (4.13 ± 2.71) compared with the initial scores (7.82 ± 1.78). In the comparison between Groups I and II, the rate of epidurographic improvement in Group I was higher than in Group II (P = 0.022). Satisfaction in patients that had epidurographic improvement (median satisfaction: 4) was higher than in patients that did not have epidurographic improvement (median satisfaction: 3; P = 0.003). CONCLUSION: The epidurographic changes following PEN correlate with patient-assessed pain relief and satisfaction.

A prospective, open-label, multicenter study of the clinical efficacy of extended-release hydromorphone in treating cancer pain inadequately controlled by other analgesics.

PURPOSE: The objective of this study was to evaluate whether extended-release hydromorphone (osmotic-controlled release oral delivery system [OROS] hydromorphone) treatment provided pain relief in cancer patients whose pain was inadequately controlled by other analgesics. METHODS: In this prospective, open-label, multicenter trial, patients who have sustained cancer pain with other analgesics were enrolled. After the baseline evaluation (visit 1), OROS hydromorphone was administered. Two evaluations (visits 2 and 3) were made: 29 ± 7 and 57 ± 7 days later, respectively. The primary end point was the pain intensity difference (PID) at visit 3 relative to visit 1 (expressed as percent PID). RESULTS: In total, 879 patients were screened and 432 completed all three visits. Of the 874 full analysis set patients, 343 (39.2 %) improved by more than 30 % PID. Of the 432 per-protocol patients, 282 (65.3 %) improved by more than 30 % PID. At visits 2 and 3, the degree of sleep disturbance, the number of awakenings, and the degree of sleep satisfaction were significantly better than at visit 1 (all P < 0.0001 for both visit 1-visit 2 and visit 1-visit 3). However, this pain relief was not associated with improved quality of life (P = 0.326 and P = 0.055 for visit 1-visit 2 and visit 1-visit 3, respectively). CONCLUSIONS: This study suggested that active pain management using the strong opioid OROS hydromorphone was beneficial in the management of cancer pain that was not controlled by other analgesics.

Analysis of the efficacy of retrodiscal approach percutaneous epidural adhesiolysis with WHIP catheter® in patients with lumbar radiculopathy: A retrospective study.

Percutaneous epidural adhesiolysis (PEA) is an effective treatment for patients with lumbar radiculopathy unresponsive to single steroid injections. Various approaches and instruments have been developed to access these lesions. This study aimed to evaluate the utility of a retrodiscal approach for epidural adhesiolysis using a WHIP catheter®. This retrospective study was conducted at Bundang Seoul National University Hospital, reviewing cases from January to December 2022. Forty-seven patients diagnosed with lumbar radiculopathy, aged 20 to 80 years, who underwent PEA with the WHIP catheter® were included. Outcomes assessed Numeric Rating Scale (NRS) for pain, Patients' Global Impression of Change (PGIC) scores, and the incidence of procedure-related complications. Follow-up evaluations occurred at 1, 3, and 6 months post-procedure. Among 47 patients, 41 completed the study, showing significant pain reduction at all follow-up points: 1 month (N = 41, 1.32 ±â€…1.68, P < .001), 3 months (N = 31, 1.90 ±â€…2.14, P < .001), and 6 months (N = 30, 2.50 ±â€…2.30, P < .001). PGIC scores indicated that 40% of the patients reported substantial improvement at one-month post-procedure. The complications were minimal, with only one case of intradiscal injection and 2 cases of vascular uptake. The retrodiscal approach PEA using the WHIP catheter® demonstrated significant efficacy in pain reduction with minimal safety concerns for patients with lumbar radiculopathy. These findings suggest that this procedure is a viable option for patients who are unresponsive to conservative treatment. However, the retrospective nature of this study and its small sample size necessitate further prospective controlled studies to confirm our results and establish long-term outcomes.

Therapeutic effect of epidural dexamethasone palmitate in a rat model of lumbar spinal stenosis.

BACKGROUND: Dexamethasone palmitate (DEP), a prodrug of dexamethasone (DEX), is a synthetic corticosteroid medication distinguished by the inclusion of a fatty acid component known as palmitate. This study introduces DEP as a novel therapeutic option for spinal epidural injection, aiming to provide safer and longer-lasting pain relief as an alternative to for patients with spinal stenosis. METHODS: 40 rats were randomly divided into four groups: those receiving epidural administration of normal saline (NS), and DEP in the lumbar spinal stenosis (LSS) model, and non-model rats receiving epidural NS administration. Paw withdrawal thresholds to mechanical stimulation and motor function (neurogenic intermittent claudication) were observed for up to 21 days. Hematology and blood chemistry analyses were performed 1 week after drug therapy. Tissue samples were collected for steroid pathology examination to evaluate adhesion degree, perineural area inflammation, and chromatolysis in the dorsal root ganglion (DRG), and adrenal gland. RESULTS: The DEX and DEP groups demonstrated significant recovery from mechanical allodynia and motor dysfunction after 2 weeks of drug therapy (p<0.001). However, by the third week, the effect of DEX started to diminish while the effect of DEP persisted. Furthermore, the DEP group exhibited reduced fibrosis and less chromatolysis than the NS group. No steroid overdose or toxin was observed in any group. CONCLUSION: The epidural administration of DEP demonstrated therapeutic efficacy in reducing allodynia and hyperalgesia resulting from chronic DRG compression, thus offering prolonged pain relief. These findings underscore the potential of DEP as a promising treatment alternative for pain associated with LSS, serving as a viable substitute for .

Effect duration of lumbar sympathetic ganglion neurolysis in patients with complex regional pain syndrome: a prospective observational study.

Lumbar sympathetic ganglion neurolysis (LSGN) has been used for long-term pain relief in patients with complex regional pain syndrome (CRPS). However, the actual effect duration of LSGN has not been accurately measured. This prospective observational study measured the effect duration of LSGN in CRPS patients and investigated the relationship between temperature change and pain relief. After performing LSGN, the skin temperatures of both the maximum pain site and the plantar area in the affected and unaffected limbs were measured by infrared thermography, and pain intensity was assessed before and at 2 weeks, 1 month, and 3 months. The median time to return to baseline temperature was calculated using survival analysis. The skin temperature increased significantly at all-time points relative to baseline in both regions (maximum pain site: 1.4 °C ± 1.0 °C, plantar region: 1.28 °C ± 0.8 °C, all P < 0.001). The median time to return to baseline temperature was 12 weeks (95% confidence interval [CI] 7.7-16.3) at the maximum pain site and 12 weeks (95% CI 9.4-14.6) at the plantar area. Pain intensity decreased significantly relative to baseline, at all-time points after LSGN. In conclusion, the median duration of the LSGN is estimated to be 12 weeks.

Development of a Deep Learning Model for the Analysis of Dorsal Root Ganglion Chromatolysis in Rat Spinal Stenosis.

Objective: To create a deep learning (DL) model that can accurately detect and classify three distinct types of rat dorsal root ganglion neurons: normal, segmental chromatolysis, and central chromatolysis. The DL model has the potential to improve the efficiency and precision of neuron classification in research related to spinal injuries and diseases. Methods: H&E slide images were divided into an internal training set (80%) and a test set (20%). The training dataset was labeled by two pathologists using pre-defined grades. Using this dataset, a two-component DL model was developed with the first component being a convolutional neural network (CNN) that was trained to detect the region of interest (ROI) and the second component being another CNN used for classification. Results: A total of 240 lumbar dorsal root ganglion (DRG) pathology slide images from rats were analyzed. The internal testing results showed an accuracy of 93.13%, and the external dataset testing demonstrated an accuracy of 93.44%. Conclusion: The DL model demonstrated a level of agreement comparable to that of pathologists in detecting and classifying normal and segmental chromatolysis neurons, although its agreement was slightly lower for central chromatolysis neurons. Significance: DL in improving the accuracy and efficiency of pathological analysis suggests that it may have a role in enhancing medical decision-making.

An alternative distal approach for the lumbar medial branch radiofrequency denervation: a prospective randomized comparative study.

BACKGROUND: An alternative technique involving a "distal approach" can be used for lumbar medial branch radiofrequency denervation (LMBRFD). We described and assessed this technique by comparing it with a conventional tunnel vision approach in a prospective randomized trial. METHODS: Eighty-two patients underwent LMBRFD by a distal (n = 41) or a tunnel vision approach (n = 41). The primary end point was a comparison of the mean difference in the change of 11-point numeric rating scale (NRS) scores of low back pain from entry to the scores at 1 month (NRS at baseline--NRS at 1 month) and at 6 months (NRS at baseline--NRS at 6 months) between the distal approach group and the tunnel vision approach group. The secondary end points were a change of NRS and the Oswestry disability index over time. RESULTS: Thirty-four patients in each group had complete time courses. There were no statistically significant differences in the change of NRS scores between the groups at 1 month (corrected P = 0.19; 97.5% 2-sided confidence interval [CI], -1.37 to 0.37) and 6 months (corrected P = 0.53; 97.5% CI, -1.36 to 0.77). Patients in both groups showed a statistically significant reduction in NRS and Oswestry disability index scores from baseline to that of the scores at 1 and 6 months (all P < 0.0001, Bonferroni corrected). The procedure-related pain score was significantly lower in the distal approach group (P = 0.001; 99% CI, -2.00 to -0.23). CONCLUSIONS: Patients who underwent LMBRFD by the tunnel vision or distal approaches showed significant pain relief at the 6-month follow-up. Less periprocedural pain was reported in the distal approach group. We consider that the distal approach provides an improved option for LMBRFD.

Interexaminer reliability of infrared thermography for the diagnosis of complex regional pain syndrome.

BACKGROUND/PURPOSE: Infrared thermography (IRT) is a useful tool for assessing skin temperature abnormalities in patients with complex regional pain syndrome (CRPS). Although determining regions of interest (ROIs) is an essential process for interpreting thermographic images, there are no validated and standardized guidelines to determine ROIs. Therefore, ROIs may be determined differently by each observer even for the same IRT images, which can result in an important issue for IRT reliability. The purpose of this study was to investigate the interexaminer reliability of IRT in patients with CRPS. METHODS: Infrared thermographic images of 28 patients diagnosed with CRPS were reviewed by three independent examiners. The shapes, sizes, and the detailed locations of the ROIs were determined by the investigator's own opinion based on patient history and symptoms. After maximal skin temperature of the ROI was obtained for each patient, the degree of agreement among the three examiners limbs was assessed. RESULTS: The intraclass correlation coefficient among the three independent raters was 0.865 (95% confidence interval, 0.748-0.933), indicating a high degree of reliability (P < 0.001). CONCLUSIONS: The reliability of IRT for assessing skin temperature abnormalities in CRPS was high when the ROIs were determined based on patient history and symptoms.

Pain from intramuscular vaccine injection in adults.

BACKGROUND: Vaccine use has been increasing worldwide, and adult populations are presented with more opportunities to experience pain from vaccine injection. The insertion of a needle through the skin is the most common source of iatrogenic pain, and needle phobia is a major concern in medical practice. However, it is unclear which factors play major roles in the perception of pain from vaccine injection in adults. AIM: To evaluate the influences of patient characteristics on pain perception due to intramuscular vaccine injection in healthy adult volunteers. MATERIAL AND METHODS: The injection of hepatitis B vaccine using a 24 mm, 24-G needle was performed as a uniform stimulus, and the intensity of injection pain was measured immediately after the injection using a 100-mm visual analogue scale (VAS). The influences of patient characteristics on pain intensity were investigated. RESULTS: One hundred sixty volunteers (65 males, 95 females) were enrolled in this study. The average VAS score was 20.8 ± 17.1 (range 0 to 67) in males and 34.4 ± 19.7 (range 2 to 76) in females (P < 0.001). However, there were no correlations between VAS score and age, body mass index or maximal pain score from previous painful experiences. The VAS score was also not affected by the experience of previous vaccine injections, a history of childbirth in females, or religion. CONCLUSIONS: Gender appears to be the only major factor that influences the pain of intramuscular vaccine injection. Therefore, pain-reducing methods will be needed when performing injection procedures, particularly in women.

Comparison of Effect and Contrast Spreading in Transforaminal Epidural Injection Using the Retrodiscal Versus Subpedicular Approach: A Prospective, Randomized Trial.

BACKGROUND: Lumbar transforaminal epidural injection (TFEI) effectively decreases low back pain and radicular pain in herniated intervertebral disc (HIVD) and spinal stenosis (SS). The precise delivery of drugs to the target is important for pain control and minimizing complications. OBJECTIVES: We aimed to evaluate the efficacy and complications of the subpedicular (SP) and retrodiscal (RD) approaches by analysis of contrast spread patterns into the pathologic target on the basis of a newly established specific criterion. We also investigated whether the severity of patients' spinal disease influenced this pattern. STUDY DESIGN: A prospective, randomized, observational study. SETTING: Interventional pain management center at a university-affiliated hospital. METHODS: Among patients who showed lumbar spinal stenosis or HIVD at the L4/5 level, participants were randomly assigned to undergo TFEI with the SP approach (SP group) or RD approach (RD group). Pain relief in terms of the visual analog scale (VAS) score and complications such as intravascular or intradiscal uptake were also analyzed. The contrast image was analyzed as the contrast media was injected, starting from 0.5 mL up to 3.0 mL. The spread patterns of contrast media were graded into 4 categories, which were newly defined in this study. RESULTS: Both groups demonstrated a significant decrease in pain relief (P value < 0.01) at 2 and 4 weeks after the procedures, but no significant difference was found between the 2 groups. In the intergroup analysis between the RD and SP groups, with a 1.5-mL contrast media injection, more patients in the RD group (17.2%) showed a grade 3 spread than those in the SP group (8.2%). In the subgroup analysis, the RD group showed superior spread (more grade 3 and 4) with 1.5-, 2-, and 2.5-mL contrast media injections (P values = 0.02, 0.03, and 0.04) in severe central stenosis, and 1.5- and 2-mL contrast media injections (P values = 0.01, 0.02) in severe foraminal stenosis. LIMITATIONS: The follow-up period was only 4 weeks after TFESI, and higher contrast injection was used for procedures. CONCLUSIONS: The RD approach for TFEI showed a better contrast spreading pattern than the SP approach, especially in patients with severe central and foraminal spinal stenosis. The RD approach might be more beneficial for patients with severe central and foraminal spinal stenosis in the short-term follow-up.

Aspirin Cessation Before Interventional Procedures: Not Blindly Following Guidelines but Making Test-based Decisions.

BACKGROUND: Deciding whether to continue or discontinue aspirin prior to interventional procedures is a major concern for pain physicians. Many guidelines have been published on the discontinuation of aspirin before invasive procedures; however, the recommendations are inconsistent and do not consider individual platelet function. Furthermore, many studies have shown a high prevalence of aspirin resistance  in patients taking this medication. OBJECTIVES: To determine the necessity of discontinuing aspirin prior to interventional pain procedures in relation to individual platelet function. STUDY DESIGN: Multicenter, cross-sectional study. SETTING: University-affiliated hospitals. METHODS: We examined platelet function among patients scheduled for an interventional pain procedure by measuring their closure time using collagen/epinephrine cartridges in a commercial platelet-function analyzer. The patients were categorized into either an aspirin-taking or nonaspirin-taking group (Group A or Group N, respectively). The proportion of patients who showed normal/abnormal platelet function was calculated and compared between the groups. RESULTS: A total of 1,111 patients were included in this study. In Group A, 56.4% (102/181) showed normal platelet function, whereas 43.6% (79/181) showed abnormal platelet function. In Group N, 85.8% (798/930) and 14.2% (132/930) showed normal and abnormal platelet function, respectively. LIMITATION: The proportion of laboratory, not clinical aspirin resistance was evaluated. Factors affecting platelet function were not investigated exhaustively. CONCLUSION: The high prevalence of normal platelet function in patients taking aspirin suggests no necessity of discontinuation before procedures in such patients. Abnormal platelet function can occur even in patients who are not taking aspirin. Therefore, platelet function should be measured and considered on a case-by-case basis prior to interventional procedures, and discontinuation of aspirin should be decided based on these factors.

Efficacy and safety of 5% lidocaine patches for postoperative pain management in patients undergoing unilateral inguinal hernia repair: study protocol for a prospective, double-blind, randomized, controlled clinical trial.

BACKGROUND: Acute postoperative pain is a common complication of inguinal hernia repair. Pain management using local application of anesthetic agents over the skin surrounding the surgical incision may reduce the requirement for other pain medications. Targeted topical analgesics such as 5% lidocaine patches have been known to improve acute and chronic pain. However, the clinical effect of lidocaine patches on postoperative pain after inguinal hernia repair has not been studied, especially in patients undergoing surgery at day surgery units. METHODS/DESIGN: This is a single-center, prospective, double-blind, randomized, controlled clinical trial. Participants with unilateral inguinal hernia will be randomized to the lidocaine patch group or the placebo patch group. Based on the randomized allocation sequence, either lidocaine patches or placebo patches will be attached near each participant's surgical wound after open hernia repair under general anesthesia. Participants will be asked to follow up at our outpatient clinic on the first postoperative day and at 1 week after surgery. The primary outcome is pain intensity, which will be measured using the visual analog scale (VAS) at the time of discharge from the day surgery unit. The secondary outcomes are VAS score at 24 h and 1 week after surgery. We will collect and analyze the participants' clinical data (amount of intraoperative opioid use, time to recovery, and pain intensity at 30 min after surgery) and demographic characteristics (age, sex, body weight, and height). DISCUSSION: This trial may not only provide evidence on the efficacy of a 5% lidocaine patch for acute postoperative pain management after unilateral inguinal hernia repair, but also demonstrate the efficacy and safety of the patch for post-discharge pain management. TRIAL REGISTRATION: ClinicalTrials.gov NCT04754451. Registered on February 10, 2021.

Efficacy and Safety of a New Sustained-release Pregabalin Formulation Compared With Immediate-release Pregabalin in Patients With Peripheral Neuropathic Pain: A Randomized Noninferiority Phase 3 Trial.

OBJECTIVE: This study investigated whether a new sustained-release (SR) pregabalin formulation is noninferior to immediate-release (IR) pregabalin in alleviating peripheral neuropathic pain in Korean patients. MATERIALS AND METHODS: This was a randomized, double-blind, active-controlled phase 3 study of patients with diabetic peripheral neuropathy or postherpetic neuralgia from 41 sites in South Korea in 2017-2018. Eligible patients were randomized (1:1) to receive once-daily SR pregabalin or twice-daily IR pregabalin (150 to 600 mg/d) in a double-dummy manner for 12 weeks according to a stratified permuted block randomization scheme. The primary endpoint was the Daily Pain Rating Scale score at the end of treatment, averaged from the last 7 available scores. RESULTS: A total of 319 of 371 (86.0%) randomized patients completed the 12-week treatment (SR pregabalin: n=154; IR pregabalin: n=165; per-protocol set: n=296). The least square mean difference between both groups for the primary endpoint was 0.06 (SE 0.19); (95% confidence interval -0.31 to 0.42), with the lower limit of the confidence interval above the pre-specified margin (-0.78; Pnoninferiority<0.0001). Drug-related treatment-emergent adverse events (TEAEs) were comparable between both groups. The incidence of drug-related TEAEs leading to treatment discontinuation was low (SR pregabalin: 2.7%; IR pregabalin: 1.1%). No serious drug-related TEAEs or deaths occurred. DISCUSSION: The results demonstrate that the new once-daily SR pregabalin formulation is noninferior to twice-daily IR pregabalin in reducing peripheral neuropathic pain and is well tolerated in Korean patients with diabetic peripheral neuropathy or postherpetic neuralgia after 12 weeks of treatment.

Early thoracic sympathetic block improves the treatment effect for upper extremity neuropathic pain.

BACKGROUND: The sympathetic nervous system has important roles in mediating many neuropathic pain conditions. A thoracic sympathetic block (TSB) is a useful therapeutic procedure for neuropathic pain in the upper extremities and thorax. However, no studies have examined the factors related to an improved therapeutic effect of TSB. In this study, we evaluated the influence of potential prognostic factors for a better TSB effect and identified clinically important prognostic factors. METHODS: Percutaneous TSB was performed in 51 patients, under fluoroscopic guidance. Data collected for each patient included age, gender, body mass index, diagnosis, pain intensity, and symptom duration. The adjusted odds ratios and 95% confidence intervals for each variable were calculated by logistic regression. RESULTS: TSB was more effective in patients with symptom durations of ≤1 year compared with >1 year (P = 0.006; odds ratio, 8.037; 95% confidence interval, 1.808-35.729). Patient age, gender, body mass index, diagnosis, and intensity of pre-TSB pain were not associated with TSB effectiveness. CONCLUSION: The results showed that an earlier TSB produced a better outcome for patients with chronic pain syndrome. Thus, early TSB should be performed in patients with chronic pain in the upper extremities.

Psychometric characteristics of the Korean version of the Roland-Morris Disability Questionnaire.

The aims of this study were; 1) to develop the final version of the Korean Roland-Morris Disability Questionnaire (RDQ), and 2) to compare the responsiveness between the RDQ and the Oswestry Disability Index (ODI) scores in patients having low back pain. The psychometric properties of the final Korean RDQ were evaluated in 221 patients. Among them, 30 patients were reliability tested. Validity was evaluated using an 11-point numerical rating scale (NRS) and the Korean ODI. The receiver operating characteristic (ROC) curve analysis of the RDQ and the ODI was compared in 54 patients with lumbar zygapophyseal (facet) joint pain. There was a moderate relationship between the RDQ and NRS (r = 0.59, P < 0.01) and a strongly positive correlation between the RDQ and the ODI (r = 0.76, P < 0.001). The Korean RDQ with the higher area under the ROC curve showed a better overall responsive performance than did the ODI in patients with lumbar facet joint pain after medial branch radiofrequency neurotomy (P < 0.01). The results of the study present the final version of the Korean RDQ is valid for assessing functional status in a Korean population with chronic low back pain.

The influence of moderate or deep neuromuscular block status on anesthetic depth monitoring system during total intravenous anesthesia using propofol and remifentanil: A randomized trial.

The neuromuscular block state may affect the electroencephalogram-derived index representing the anesthetic depth. We applied an Anesthetic Depth Monitoring for Sedation (ADMS) to patients undergoing laparoscopic cholecystectomy under total intravenous anesthesia, and evaluated the requirement of propofol according to the different neuromuscular block state. Adult patients scheduled to undergo laparoscopic cholecystectomy were enrolled and randomly assigned to either the moderate (MB) or deep neuromuscular block (DB) group. The UniCon sensor of ADMS was applied to monitor anesthetic depth and the unicon value was maintained between 40 and 50 during the operation. According to the group assignment, intraoperative rocuronium was administered to maintain proper neuromuscular block state, moderate or deep block state. The unicon value, electromyography (EMG) index, and total dose of propofol and rocuronium were analyzed. At similar anesthetic depth, less propofol was used in the DB group compared to the MB group (6.19 ± 1.36 in the MB mg/kg/h group vs 4.93 ± 3.02 mg/kg/h in the DM group, p = 0.042). As expected, more rocuronium were used in the DB group than in the MB group (0.8 ± 0.2 mg/kg in the MB group vs 1.2 ± 0.2 mg/kg in the DB group, p = 0.023) and the EMG indices were lower in the DB group than in the MB group, at several time points as follows: at starting operation (p < 0.001); at 15 (p = 0.019), 45 (p = 0.011), and 60 min (p < 0.001) after the initiation of the operation; at the end of operation (p = 0.003); and at 5 min after the administration of sugammadex (p < 0.001). At similar anesthetic depth, patients under the deep neuromuscular block state required less propofol with lower intraoperative EMG indices compared to those under the moderate neuromuscular block state during general anesthesia.