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Seon Ju Kim, Sang Jun Park, Duck Mi Yoon, Kyung Bong Yoon, Shin Hyung Kim Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea Background: Pulsed radiofrequency (RF) targeting the adjacent dorsal root ganglion (DRG) is one treatment option for lumbosacral radicular pain. However, the analgesic efficacy of this procedure is not always guaranteed. The aim of this retrospective study was to identify the predictors of the analgesic efficacy of pulsed DRG RF treatment in patients with chronic lumbosacral radicular pain. Methods: Patients who underwent pulsed DRG RF treatment from 2006 to 2017 at our clinic were enrolled. Positive response was defined as a ≥50% reduction in pain score from baseline at day 30. Patient demographics, pain-related factors, and clinical factors were evaluated using logistic regression analysis to identify the predictors of a positive response to the treatment. Results: A total of 60 patients satisfied the study protocol requirements. Twenty-eight patients (46.7%) had a positive outcome. Multivariate logistic regression analysis revealed that the absence of comorbid musculoskeletal pain (OR=0.518, 95% CI=0.029–0.858, P=0.033) and positive response to previous epidural steroid injection (OR=3.269, 95% CI=1.046–10.215, P=0.042) were independent predictors of the analgesic efficacy of pulsed DRG RF treatment. Conclusion: Comorbid musculoskeletal pain and previous epidural injection response appear to affect the outcome of pulsed DRG RF treatment in patients with chronic lumbosacral radicular pain. Keywords: pulsed radiofrequency, dorsal root ganglion, lumbosacral radicular pain, predictors, efficacy

Objective The aim of this study was to investigate the effect of skin pressure on needle entry point accuracy during fluoroscopically guided lumbar transforaminal epidural injection. Design This study is a prospective randomized clinical trial; 64 patients with a body mass index of 25 kg/m or greater were enrolled. For patients in the pressing group, the operator marked the needle entry point on the patient's back while pressing the patient's skin with the tip of an indicator. For patients in the nonpressing group, the tip of the indicator was gently positioned on the patient's skin. The data related to technical performance and radiation exposure during the procedure were compared. Results Sixty patients (nonpressing group, n = 30; pressing group, n = 30) were analyzed. There were more attempts to reposition the needle (n) and increased procedure time (in seconds) in the pressing group (median, 5 vs. 4 [P = 0.019]; 400.0 vs. 358.5 [P = 0.033]). The fluoroscopy time (in seconds) and the kerma-area product (in cGy cm) were also significantly longer and greater in the pressing group, respectively (median, 63.5 vs. 50.5 [P = 0.038]; 416.3 vs. 318.6 [P = 0.014]). Conclusions This study shows that practitioners should not press the skin with a radiopaque indicator when determining the needle entry point by fluoroscopy during lumbar transforaminal epidural injection.

Objective . To determine the risk factors associated with clinical insomnia in postherpetic neuralgia (PHN) patients. Design . A retrospective cross-sectional study. Setting . Outpatient department for interventional pain management at a university hospital. Subjects . A total of 111 patients with PHN satisfied the study inclusion criteria and were included in the analyses. Methods . The Insomnia Severity Index (ISI) was used to determine the presence of clinical insomnia (ISI score ≥ 15). Patient demographics, pain-related factors, and rash severity and location were evaluated with logistic regression analysis to identify risk factors of clinical insomnia among patients with PHN. Results . In total, 50.5% of patients reported mild to severe insomnia symptoms (ISI score ≥ 8) after pain development. Moderate to severe clinical insomnia (ISI score ≥ 15) was observed in 30.6% of PHN patients. Multivariate logistic regression analyses revealed that high pain intensity was the strongest predictor of clinical insomnia (odds ratio (OR) = 12.417, 95% confidence interval (CI): 2.990–51.561, P = 0.001). However, presence of mechanical allodynia (OR = 4.263, 95% CI: 1.040–17.481, P = 0.034) and high anxiety and depression level (OR = 4.452, 95% CI: 1.201–16.508, P = 0.026; OR = 6.975, 95% CI: 1.425–34.138, P = 0.017) were also significantly associated with clinical insomnia after adjusting for pain score. Clinical insomnia was not significantly related to age, gender, rash severity, or location of skin lesion. Conclusions . Insomnia should be addressed as an important part of pain management in PHN patients with these risk factors, especially in patients with severe pain.

Background: Insomnia is highly prevalent among people with chronic pain conditions. Because insomnia has been shown to worsen pain, mood, and physical functioning, it could negatively impact the clinical outcomes of patients with chronic pain. Objective: To determine the risk factors associated with clinical insomnia in chronic neck pain (CNP) patients. Study Design: Retrospective analysis. Setting: Outpatient department for interventional pain management at a university hospital. Methods: Data from 218 CNP patients were analyzed in this study. The Insomnia Severity Index (ISI) was used to determine the presence of clinical insomnia (ISI score ≥ 15). Patient demographics and pain-related factors were evaluated with logistic regression analysis to identify risk factors of clinical insomnia in CNP. Results: In total, 53.7% of patients reported mild to severe insomnia after neck pain development; 22.9% of patients met the criteria for clinically significant insomnia (ISI score ≥ 15). In multivariate analysis, high pain intensity, the presence of comorbid musculoskeletal pain, and a high level of depression were strongly associated with clinical insomnia in patients with CNP. Among these factors, a greater level of depression was the strongest predictor of clinical insomnia, with the highest odds ratio of 3.689 (95% CI 1.570 – 8.667). Limitations: This study was conducted in a single clinical setting including a selected study population with a homogeneous racial background. The ISI does not include several sleep-related variables, the roles of which are unknown in determining insomnia severity. Conclusions: Insomnia should be addressed as an indispensable part of pain management in CNP patients with these risk factors, especially depression. Key words: Chronic neck pain, insomnia, risk factors, pain severity, neuropathic pain, musculoskeletal pain, depression

Summary The aim of this randomised study was to compare the incidence of intravascular injections during S1 transforaminal epidural steroid injection performed in the anteroposterior and oblique views. We also compared epidural spread patterns of contrast media, which included 201 injections at the S1 level. The overall incidence of intravascular injection during S1 transforaminal epidural steroid injection in the anteroposterior view was 29% (29/99), significantly higher than in the oblique view (11%, 11/102, p = 0.001). There were no significant differences between the two groups for epidural spread of contrast media in cases where intravascular injections did not occur (p = 0.77). Performing S1 transforaminal epidural steroid injection in the oblique view rather than the anteroposterior view reduces the risk of intravascular injections.

The purpose of this study was to elucidate the effects of injection at trigger points on pain and sleep disturbance in patients with nocturnal calf cramps (NCCs).Patients with NCCs that occurred at least once per week and who had myofascial trigger points (MTrPs) on the gastrocnemius muscles were enrolled in the study for 9 months. At the first visit (T0), we measured the intensity of NCC pain on an 11-point numeric rating scale, recorded the frequency of NCCs, and calculated the Insomnia Severity Index (ISI). We then checked for MTrPs on the gastrocnemius muscles and injected 1-2 mL of 0.25% lidocaine into each of the trigger points. At 1 (T1), 2 (T2), and 4 (T3) weeks after the first visit, we repeated the process performed at T0.Twelve patients completed the treatment schedule and attended the follow-up visits. Mean values of the numeric rating scale pain score, frequency of cramps, and ISI declined significantly at T1, T2, and T3 compared with baseline (all P.01). Of 12 patients, 10 had clinical insomnia before treatment, and this number decreased significantly to 3 patients at T2 and 1 patient at T3 (P = .012 and P = .001, respectively).These preliminary data show that injection at MTrPs in patients with NCCs not only alleviated pain and reduced the frequency of cramps but also lessened the severity of insomnia as measured by the ISI. A larger randomized controlled trial is needed to confirm these findings and determine whether the effect lasts over the long term.

Purpose. Intravascular injection rates are higher during traditional S1 transforaminal epidural steroid injection (TFESI) compared with lumbar transforaminal injection. We compared the incidences of intravascular injection between the medial and lateral approaches to the S1 foramen during S1 TFESI. Materials and Methods. A total of 139 patients underwent one or more TFESIs (170 total injections). The patients received S1 TFESI by either medial or lateral side of S1 foramen under fluoroscopic anteroposterior view using digital subtraction method. The intravascular injection rates, epidural spread patterns, and contrast volumes required to reach the superior aspect of the L5-S1 intervertebral disc (SIVD) were compared between groups. Results. Intravascular injection rates during S1 TFESI were significantly lower in the medial approach compared with the lateral approach patients (4.9% versus 38.6%, resp., P<0.001). The medial approach group had more epidural spread to the L5-S1 SIVD than the lateral group (82.1% versus 58.8%, resp.); lower contrast volume amounts were required to extend the L5-S1 SIVD (1.46±0.48 versus 1.90±0.62, resp.). Conclusion. During S1 TFESI, approaching the needle towards the medial part of the S1 foramen may reduce intravascular injection risk.

Background Axillary nerve block (ANB) was recently introduced along with suprascapular nerve block as an alternative to inter-scalene brachial plexus block for post-operative pain control. However, the methods for performing ANB are variable. We studied the relationship between surface anatomy and the location of the axillary nerve in the quadrilateral space to ensure a technically safe and simple ANB. Methods Eighty-eight shoulders were included. All measurements were performed with the subjects seated and the shoulders in a neutral position. We located the posterior circumflex humeral artery (PCHA) using a vascular Doppler system and named this point ‘AN’. We used this point to locate the axillary nerve, since this nerve is generally present with the PCHA in the quadrilateral space. We then examined the relationship between surface anatomic landmarks and AN. The depth of the medial side of the humerus at the AN (AN depth), which is at the lateral border of the quadrilateral space, was measured using ultrasonography. Results AN was located on the line between the posterolateral corner of the acromion (Ac) and the axillary fold (Axf) (Ac–Axf) in 77% of shoulders. The ratio of the distance from Ac to AN (Ac–AN) to Ac–Axf in all shoulders was 0.6 [standard deviation (SD), 0.1]. AN depth was 4.0 (SD, 0.5) cm in men and 3.6 (SD, 0.4) cm in women. Conclusion Knowledge of the relationship between surface anatomy and AN, as well as estimated AN depth may aid in locating the axillary nerve in the quadrilateral space.

Erythromelalgia is a rare neurovascular pain syndrome characterized by a triad of redness, increased temperature, and burning pain primarily in the extremities. Erythromelalgia can present as a primary or secondary form, and secondary erythromelalgia associated with a myeloproliferative disease such as essential thrombocythemia often responds dramatically to aspirin therapy, as in the present case. Herein, we describe a typical case of a 48-year-old woman with secondary erythromelalgia linked to essential thrombocythemia in the unilateral hand. As this case demonstrates, detecting and visualizing the hyperthermal area through infrared thermography of an erythromelalgic patient can assist in diagnosing the patient, assessing the therapeutic results, and understanding the disease course of erythromelalgia.

Glomus tumors are benign tumors that account for 1% to 5% of all soft tissue tumors of the hand and are characterized by a triad of sensitivity to cold, localized tenderness and severe paroxysmal pain. Paroxysmal pain is a symptom common not only in glomus tumors but also in CRPS, and the hand is one of the commonly affected sites in patients with both glomus tumors and CRPS. Therefore, it is not easy to clinically diagnose glomus tumors superimposed on already affected region of CRPS patients. We report a case of glomus tumor concomitantly originating with CRPS at the hand.

Background Good postoperative pain control is an important part of adequate postoperative care. Patient-controlled epidural analgesia (PCEA) provided better postoperative analgesia compared to other conventional analgesic methods, but several risks have been observed as well. We therefore surveyed the efficacy and safety of PCEA in this retrospective observational study. Methods We analyzed collected data on 2,276 elective surgical patients who received PCEA with ropivacaine and fentanyl. Patients were assessed by a PCA service team in the post-anesthesia care unit (PACU), at 1-6 h, 6-24 h, and 24-48 h postoperatively for adequate pain control. The presence of PCEA-related adverse events was also assessed. Results Numerical pain score (median [interquartile range]) were 3 [1-4], 5 [4-7], 4 [3-5], and 3 [3-5] in the PACU, at 1-6 h, 6-24 h, and 24-48 h postoperatively. Median pain scores in patients underwent major abdominal or thoracic surgery were higher than other surgical procedure in the PACU, at 1-6 h after surgery. Nausea and vomiting (20%) and numbness and motor weakness (15%) were revealed as major PCEA-related adverse events during the postoperative 48 h period. There were 329 patients (14%) for whom PCEA was ceased within 48 h following surgery. Conclusions Our data suggest that the use of PCEA provides proper analgesia in the postoperative 48 h period after a wide variety of surgical procedures and that is associated with few serious complications. However, more careful pain management and sustainable PCEA monitoring considering the type of surgical procedure undergone is needed in patients with PCEA.

To evaluate the clinical effectiveness of botulinum toxin (BTX) injection into the gastrocnemius muscles in patients with lumbar spinal stenosis (LSS) who have frequent nocturnal calf cramps (NCCs).Prospective, randomized clinical trial.Outpatient department for interventional pain management.Patients (N=50) with LSS who have NCCs at least once per week were enrolled.Patients were randomly allocated to receive either conservative treatments plus gabapentin (group GPN) or BTX injection (group BTX).We assessed back/leg pain intensity, the frequency and severity of NCCs, insomnia severity, and functional disability at baseline and after 2 weeks, 1 month, and 3 months. Additionally, Patient Global Impression of Change was assessed.Forty-five patients completed all assessments (group GPN, n=21; group BTX, n=24). Compared with group GPN, leg pain intensity, cramp frequency, and cramp severity were significantly decreased in group BTX at all follow-up visits (all, P.01). Also, insomnia significantly improved in group BTX at the 2-week (P=.018) and 1-month follow-up (P=.037). Functional disability significantly improved in group BTX at 2 weeks' follow-up (P=.041). At the 3-month follow-up, patients in group BTX reported a higher impression of improvement for NCC symptoms than did those in group GPN (P.001). A mean dose of 642.8mg of gabapentin was given daily in group GPN, but 7 patients (33.3%) reported systemic side effects. There were no serious complications related to BTX use.BTX treatment appears to be effective and safe for NCCs in symptomatic LSS patients receiving conservative care.

Background: The quadratus femoris (QF) muscle is a possible source of lower buttock pain as evidenced by what is known about the pathophysiology of ischiofemoral impingement syndrome. However, there are few reports about the interventional management of the QF muscle as a pain generator. Objective: To describe an ultrasound-guided QF muscle injection technique in patients with lower buttock pain suspected of QF muscle pathology and to report the result of treatment. Study Design: Retrospective evaluation. Setting: Outpatient department for interventional pain management at a university hospital. Methods: We studied 14 patients who had deep tenderness localized to the lower buttock region at a point halfway between the lateral prominence of the greater trochanter and the ischial tuberosity corresponding to the location of the QF muscle belly. Under ultrasound guidance, 8 mL of 0.25% lidocaine was injected into the QF muscle. Pain scores were assessed prior to the first injection and 2 weeks after the last injection. Patient satisfaction was also assessed. Results: When compared before and 2 weeks after last QF muscle injection, the mean pain score decreased by 49.3% (6.7 ± 2.3 to 3.4 ± 2.1, P < 0.001). Two weeks after the last injection, approximately 70% of patients (10 of 14 patients) expressed their satisfaction as excellent or good and the average frequency of injection was 2.5 times. There were no complications observed. Limitations: The results of this study should be considered preliminary owing to the small sample size and lack of a control group, and the retrospective characteristics of this study may have introduced a selection bias. Conclusions: Ultrasound-guided QF muscle injection with local anesthetic helps alleviate pain in patients with lower buttock pain attributed to the QF muscle, and leads to high levels of satisfaction for patients. A randomized placebo-controlled trial should be considered in the future. Key words: Buttocks, injections, intramuscular, myofascial pain syndromes, quadratus femoris, ultrasonography

Because of its anatomical location and function, the costotransverse (CTRV) joint can be a source of thoracic back pain. In this retrospective observational study, we evaluated the clinical effectiveness of the CTRV joint injection in thoracic back pain patients with suspected CTRV joint problems. We enrolled 20 thoracic back pain patients with localized tenderness that was provoked by the application of pressure on the affected CTRV joints. We injected it with 0.5 ml of a ropivacaine and triamcinolone mixture at each level. The mean pre-injection pain score decreased by 37.9% (7.2 ± 1.5 to 4.5 ± 1.7, P < 0.001) two weeks after CTRV joint injection. In addition, 70% of patients reported an excellent or good level of satisfaction. We demonstrated that an ultrasound-guided injection of the CTRV joint reduced patients' pain scores and led to a high level of satisfaction at short-term follow-ups in patients with suspected CTRV joint problems.

Intracranial hypotension is characterized by a postural headache which is relieved in a supine position and worsened in a sitting or standing position. Although less commonly reported than postural headache, sixth nerve palsy has also been observed in intracranial hypotension. The epidural blood patch (EBP) has been performed for postdural puncture headache, but little is known about the proper timing of EBP in the treatment of sixth nerve palsy due to intracranial hypotension. This article reports a case of sixth nerve palsy due to spontaneous intracranial hypotension which was treated by EBP 10 days after the onset of palsy.

We used caudal epidurography to compare the spread of contrast medium when the needle was inserted toward the affected side in patients with unilateral radiculopathy undergoing caudal steroid injection.We enrolled 24 patients with unilateral radiculopathy. A block needle was positioned toward the affected side in the sacral epidural space. After 5 mL of iodinated contrast medium was injected, a standardized anteroposterior view was imaged. Using Adobe Photoshop software, contrast medium spread was assessed by counting pixels within the areas spread on the affected side and on the opposite side, and the pixel counts of the two sides were compared. Spinal nerve root filling was also assessed.The pixel count within the area of contrast medium spread on the side with the needle was significantly greater than that of the opposite side (mean [SD] 41,368.6 [13,143.1] vs 15,165.3 (10,698.1), P 0.001]. However, 13.6% of the study patients had greater spread on the opposite side. The rates of L5 and S1 nerve root filling in the affected side were 18.2% and 36.4% respectively.When a needle was intentionally inserted toward the side with radiculopathy, the spread of contrast medium and number of delineated roots tended to be greater on the side with the needle, compared with those on the opposite side. However, the pattern of contrast medium spread in the sacral epidural space varied and some patients even had greater spread on the opposite side.

Insomnia is highly prevalent among people with chronic pain conditions. Because insomnia has been shown to worsen pain, mood, and physical functioning, it could negatively impact the clinical outcomes of patients with chronic pain.To determine the risk factors associated with clinical insomnia in chronic neck pain (CNP) patients.Retrospective analysis.Outpatient department for interventional pain management at a university hospital.Data from 218 CNP patients were analyzed in this study. The Insomnia Severity Index (ISI) was used to determine the presence of clinical insomnia (ISI score ≥ 15). Patient demographics and pain-related factors were evaluated with logistic regression analysis to identify risk factors of clinical insomnia in CNP.In total, 53.7% of patients reported mild to severe insomnia after neck pain development; 22.9% of patients met the criteria for clinically significant insomnia (ISI score ≥ 15). In multivariate analysis, high pain intensity, the presence of comorbid musculoskeletal pain, and a high level of depression were strongly associated with clinical insomnia in patients with CNP. Among these factors, a greater level of depression was the strongest predictor of clinical insomnia, with the highest odds ratio of 3.689 (95% CI 1.570-8.667).This study was conducted in a single clinical setting including a selected study population with a homogeneous racial background. The ISI does not include several sleep-related variables, the roles of which are unknown in determining insomnia severity.Insomnia should be addressed as an indispensable part of pain management in CNP patients with these risk factors, especially depression.This study is a retrospective analysis. IRB No: 4-2014-0801.

Background Stellate ganglion block is usually performed at the transverse process of C6, because the vertebral artery is located anterior to the transverse process of C7. The purpose of this study is to estimate the location of the transverse process of C6 using the cricoid cartilage in the performance of stellate ganglion block. Methods We reviewed cervical lateral neutral-flexion-extension views of 48 patients who visited our pain clinic between January and June of 2010. We drew a horizontal line at the surface of the cricoid cartilage in the neutral and extension views of cervical lateral x-rays. We then measured the change in the shortest distance from this horizontal line to the lowest point of the transverse process of C6 between the neutral and extension views. Results There was a statistically significant difference in the shortest distance from the horizontal line at the surface of the cricoid cartilage to the lowest point of transverse process of C6 between neutral position and neck extension position in both males and females, and between males and females in both neutral position and neck extension position. The cricoid cartilage level was 4.8 mm lower in males and 14.4 mm higher in females than the lowest point of transverse process of C6 in neck extension position. Conclusions Practitioners should recognize that the cricoid cartilage has cephalad movement in neck extension. In this way, the cricoid cartilage can be still useful as a landmark for stellate ganglion block.

Pulsed radiofrequency (PRF) treatment of nervous tissue has been proposed as a less neurodestructive technique alternative to continuous RF heat lesioning. Recently, clinical reports using PRF have shown favorable effects in the treatment of a variety of focal pain areas, even in non-nervous tissues; however, the mechanism of effect underlying this treatment to non-nervous tissue remains unclear. We report the case of a 67-year-old male who presented with pain reliving point in the posterior neck. The patient had pain in the posterior neck for 3 years. The pain subsided with pressure applied to a point in the posterior neck. There were no specific abnormal findings on laboratory testing and radiologic examinations. After PRF treatment to the pain-relieving point, he had pain relief which lasted more than 5 months.

Background: The first sacral nerve root block (S1NRB) is a common procedure in pain clinic for patients complaining of low back pain with radiating pain. It can be performed in the office based setting without C-arm. The previously suggested method of locating the needle entry point begins with identifying the posterior superior iliac spine (PSIS). Then a line is drawn between two points, one of which is 1.5 cm medial to the PSIS, and the other of which is 1.5 cm lateral and cephalad to the ipsilateral cornu. After that, one point on the line, which is 1.5 cm cephalad to the level of the PSIS, is considered as the needle entry point. The purpose of this study was to analyze the location of needle entry point and palpated PSIS in S1NRB. Methods: Fifty patients undergoing C-arm guided S1NRB in the prone position were examined. The surface anatomical relationships between the palpated PSIS and the needle entry point were assessed. Results: The analysis revealed that the transverse and vertical distance between the needle entry point and PSIS were 28.7 ± 8.8 mm medially and 3.5 ± 14.0 mm caudally, respectively. The transverse distance was 27.8 ± 8.3 mm medially for male and 29.5 ± 9.3 mm medially for female. The vertical distance was 1.0 ± 14.1 mm cranially for male and 8.1 ± 12.7 mm caudally for female. Conclusions: The needle entry point in S1NRB is located on the same line or in the caudal direction from the PSIS in a considerable number of cases. Therefore previous recommended methods cannot be applied to many cases. (Korean J Pain 2010; 23: 242-246)

Background Stellate ganglion block (SGB) is known to increase blood flow to the innervations area of the stellate ganglion. Near infrared spectroscopy reflects an increased blood volume and allows continuous, non-invasive, and bedside monitoring of regional cerebral oxygen saturation (rSO2). We investigated the influence of SGB on bilateral cerebral oxygenation using a near infrared spectroscopy. Methods SGB was performed on 30 patients with 1% lidocaine 10 ml using a paratracheal technique at the C6 level and confirmed by the presence of Horner's syndrome. The blood pressure (BP), heart rate (HR) and rSO2 were measured before SGB and 5, 10, 15 and 20 minutes after SGB. Tympanic temperature of each ear was measured prior to SGB and 20 minutes after SGB. Results The increments of the rSO2 on the block side from the baseline were statistically significant at 5, 10, 15 and 20 minutes. The rSO2 on the non-block side compared with the baseline, however, decreased at 15 and 20 minutes. The difference between the block and the non-block sides was significant at 15 and 20 minutes. The BP at 10, 15 and 20 minutes was increased and the HR was increased at 10 and 15 minutes. Conclusions We observed an increment of the rSO2 on the block side from the baseline; however, the rSO2 on the non-block side decreased.

Background: Fluoroscopy has been an integral part of modern interventional pain management. Yet fluoroscopy can be associated with risks for the patients and clinicians unless it is managed with appropriate understanding, skill and vigilance. Therefore, this study was designed to determine the amount of radiation received by a primary operator and an assistant during interventional pain procedures that involve the use of fluoroscopy. Methods: In order to examine the amount of radiation, the physicians were monitored by having them wear three thermoluminescent badges during each single procedure, with one under a lead apron, one under the apron collar and one on the leg during each single procedure. The data obtained from each thermoluminescent badge was reviewed from September 2008 to November 2008 and the annual radiation exposure was subsequently calculated. Results: A total of 505 interventional procedures were performed with C-arm fluoroscopy during three months. The results of this study revealed that the annual radiation exposure was relatively low for both the operator and assistant. Conclusions: With proper precautions, the use of fluoroscopy during interventional pain procedures is a safe practice. (Korean J Pain 2010; 23: 24-27)

More than 80% of cancer-related pain is pharmacologically controllable, whereas 10∼20% of patients require interventional treatments. Neurolytic nerve block can play a major role in cancer pain treatment, and it has been proposed to prevent the development of pain and improve the quality of life of patients with cancer. If the pain is well localized and restricted to certain peripheral parts of the body, spinal peripheral or sympathetic nerve blocks may result in excellent therapeutic effects. Neurolytic sympathetic block, especially Celiac plexsus block (CPB) performed in earlier stages, is effective with successful long term results. However, selection of patients is critical for succeful outcomes. Neurolytic plexus block significantly improves the quality of life of patients and reduces abdominal and pelvic cancer pain, analgesic consumption and adverse opioids-related side effects. Interventional pain management should be considered at earlier stages to provide patients with the best quality of life possible. (Korean J Hosp Palliat Care 2009;12:56-60)Key Words: Nerve block, Celiac plexsus block, Cancer pain서론 진행된 암성통증의 80∼90%는 진통제를 투여하는 약물치료로 잘 조절되지만 약물치료에 반응하지 않는 경우 신경블록을 고려하게 된다.

Optic nerve sheath diameter (ONSD) measurement using ocular ultrasonography was introduced as a non-invasive technique to assess intracranial pressure. We investigated changes in ONSD after cervical sympathetic block (CSB). Ultrasound-guided CSB was performed with a lateral approach at the C6 level in 35 patients. ONSD was measured before CSB and after checking for Horner's syndrome 15 minutes after CSB. The mean ONSD was significantly higher after CSB than before (5.15 ± 0.38 mm vs. 4.75 ± 0.32 mm, p < 0.001). A comparison of ONSDs between the blocked and non-blocked sides revealed that these values did not differ significantly between sides at baseline and after CSB. On the basis of these preliminary data, CSB caused an increase in ONSD in patients without intracranial pathology or neurologic disorders. Further larger and controlled studies of the effect of CSB on intracranial pressure in humans are needed to confirm our findings.

Hyaluronidase has been gaining interest because it reduces tissue edema and fibrosis. Although rare, hyaluronidase has been shown to cause allergic reactions. A few cases of allergic reactions following hyaluronidase administration have been reported. Most of the described patients presented allergic reactions after peribulbar anesthesia for eye surgery. In this report, we describe three patients who experienced with allergic reactions to hyaluronidase following pain management. Two of the patients had a history of uneventful injection with hyaluronidase. All patients were afebrile and blood tests results were normal. Intradermal skin tests were positive. These clinical findings were helpful in establishing the differential diagnosis of infection. Although allergic reaction to hyaluronidase is rare and mostly benign, this must be considered before treating patients.

Background: Insomnia is becoming increasingly recognized as a clinically important symptom in patients with chronic low back pain (CLBP). In this retrospective study, we have determined risk factors associated with clinical insomnia in CLBP patients in a university hospital in Korea. Methods: Data from four-hundred and eighty one CLBP patients was analyzed in this study. The Insomnia Severity Index (ISI) was used to determine the presence of clinical insomnia (ISI score ≥ 15). Patients’ demographics and pain-related factors were evaluated by logistic regression analysis to identify risk factors of clinical insomnia in CLBP. Results: It was found that 43% of patients reported mild to severe insomnia after the development of back pain. In addition, 20% of patients met the criteria for clinically significant insomnia (ISI score ≥ 15). In a stepwise multivariate analysis, high pain intensity, the presence of comorbid musculoskeletal pain and neuropathic pain components, and high level of depression were strongly associated with clinical insomnia in CLBP. Among these factors, the presence of comorbid musculoskeletal pain other than back pain was the strongest determinant, with the highest odds ratio of 8.074 (95% CI 4.250 to 15.339) for predicting clinical insomnia. Conclusions: Insomnia should be addressed as an integral part of pain management in CLBP patients with these risk factors, especially in patients suffering from CLBP with comorbid musculoskeletal pain. (Korean J Pain 2015; 28: 137-143)

Background Central sensitization plays an important role in the chronic pain experienced by osteoarthritis (OA) patients. In this prospective observational study, we investigated the influence of the level of preoperative centrally mediated symptoms measured by the Central Sensitization Inventory (CSI) on pain intensity after total knee arthroplasty (TKA) for OA. Methods Ninety-eight female OA patients undergoing TKA were enrolled in this study. We assessed CSI scores, pain-related data, and other clinical data preoperatively. All patients received spinal anesthesia and postoperative epidural analgesia. Pain intensity (at rest and on movement) and rescue meperidine requirements were assessed during postoperative days 1 and 2. Also, pain intensity and patient satisfaction were assessed 1 month and 3 months after surgery. After the completion of all postoperative assessments, we separated the study population into a preoperative CSI score ≥40 and

Background Because of its anatomical location and function, the obturator externus (OE) muscle can be a source of pain; however, this muscle is understudied as a possible target for therapeutic intervention in pain practice. In this retrospective observational study, we evaluated the clinical effectiveness of the OE muscle injection with a local anesthetic in chronic pelvic pain patients with suspected OE muscle problems. Methods Twenty-three patients with localized tenderness on the inferolateral side of the pubic tubercle accompanied by pain in the groin, anteromedial thigh, or hip were studied. After identifying the OE with contrast dye under fluoroscopic guidance, 5 to 8 mL of 0.3% lidocaine was injected. Pain scores were assessed before and after injection; patient satisfaction was also assessed. Results Mean pain score decreased by 44.7% (6.6 ± 1.8 to 3.5 ± 0.9, P

Background: Evidence for opioid-induced hyperalgesia (OIH) has been shown in animal and human studies, but the clinical implications of this phenomenon remain unclear. Objectives: We examined whether cancer patients taking opioids differ in their sensitivity to a clinical pain stimulus using a local anesthetic injection compared to those not taking opioids. We also evaluated the effect of the opioid dose, duration of opioid therapy, and patients’ pain severity and functional status on this clinical pain stimulus. Study Design: Prospective observational study. Setting: University outpatient department for interventional pain management, Republic of Korea. Methods: Eighty-two cancer patients including 20 patients not taking opioids (non-opioid group) and 62 taking opioids (opioid group) who were scheduled for an interventional procedure were enrolled in this study. Patients received a standardized subcutaneous injection of lidocaine prior to a full dose of local anesthetic (LA). Before the injection, patients completed the Brief Pain Inventory (BPI) questionnaire and were asked to rate their current pain using numeric rating scales. Immediately following the injection, LA injection-specific pain was evaluated using pain intensity, unpleasantness, and behavior pain scores. Results: LA injection-specific pain intensity, unpleasantness, and behavior pain score were significantly higher in the opioid group compared with the non-opioid group (P < 0.001). In the opioid group, these post-injection pain scores were higher in patients taking high-dose opioids than those taking low doses (P < 0.05). In addition, we observed a strong correlation between the baseline BPI pain interference score and the LA injection-specific pain score (r = 0.695, P < 0.001). Limitations: This study is limited by its sample size and observational design. Various opioid medications, which were not standardized, may have inadvertently biased our results. Finally, the pain assessed by a brief stimulus does not fully reflect disturbances in endogenous pain inhibitory processes. Conclusion: The results of this study suggest that opioid medication is an important contributing factor to pain perception accompanying LA injection, and cancer patients using high-dose opioids may be highly susceptible to hyperalgesic responses to this clinical stimulus. We also suggest that the possible presence of OIH may be intensified among cancer patients with poor physical and psychosocial functional status. Key words: Adverse effects; analgesics, opioid; anesthetics, local; cancer; hyperalgesia; injections, subcutaneous; nociceptive pain; pain measurement; pain perception; quality of life

Background: Stellate ganglion block (SGB) causes sympathetic denervation of the head, neck, and upper extremities. In some studies, it has been reported that cerebral blood flow on the nonblocked side decreases after SGB, so when performing an SGB for pain management of the head, neck, and arm, the increased risk of cerebral ischemia should be considered. Objectives: To examine the influence of administration of oxygen via nasal cannula after SGB on regional cerebral oxygen saturation (rSO2) of the non-blocked and blocked sides using nearinfrared spectroscopy (NIRS). Study Design: Prospective observational study. Setting: Outpatient department for interventional pain management at Yonsei University College of Medicine, Seoul, Korea Methods: Thirty-eight patients with disease entities in the head, neck, and upper extremity and 3 volunteers were studied. SGB was performed with 10 mL of 1% lidocaine using an anterior paratracheal approach at the C6 transverse process level. A successful block was determined based on the appearance of Horner syndrome at 15 minutes after SGB. Oxygen was supplied at a rate of 5 L/min via nasal cannula starting 15 minutes after SGB. rSO2, blood pressure (BP), and heart rate (HR) were obtained at 5-minute intervals for 30 minutes using NIRS, a non-invasive blood pressure manometer, an electrocardiogram, and a pulse oximetry. Results: On the non-blocked side, when compared to the baseline values, there were significant decreases in the rSO2 (P < 0.001) and after administration of oxygen, there were significant increases of the rSO2 compared to the rSO2 at 15 minutes (P < 0.001). The lowest rSO2 at 15 minutes on the non-blocked side recovered to greater than the baseline value 5 minutes after starting oxygen administration. On the blocked side, when compared to the baseline values, there were significant increases at all time points (P < 0.001) and after administration of oxygen there were significant increases compared to the rSO2 at 15 minutes (P < 0.001). The rSO2 on the blocked side and the non-blocked side were significantly different at 15 minutes (P = 0.015). After oxygen administration, there were no significant differences of rSO2 between the 2 sides. Limitations: This study is limited by its sample size and observational design. It is difficult to precisely define the importance of the effect of SGB and oxygen administration on rSO2 change as we did not examine how the intensity of the nerve block changed with the passage of time. Conclusion: SGB leads to decreased cerebral blood flow of the non-blocked hemisphere, and oxygen administration seems to be a simple method to compensate for this response. Clinical Trial: NCT01532713. IRB No.: 4-2011-0358. Key words: Brain ischemia, cerebrovascular circulation, nerve block, oximetry, oxygen, regional blood flow, spectroscopy, near-infrared, stellate ganglion

Background Chronic musculoskeletal pain is highly prevalent, disabling, and costly, and has many negative effects on quality of life. The aim of this study was to investigate factors associated with higher reported pain levels in patients with chronic musculoskeletal pain among demographic, clinical, and psychological factors, and to evaluate whether insomnia is independently associated with pain intensity in this population. Methods A total of 357 patients with chronic musculoskeletal pain (pain duration ≥ six months) satisfied the study inclusion criteria and were included in the analyses. Patient demographics, clinical, and psychological factors were evaluated with hierarchical multivariate logistic analysis to identify factors associated with severe pain (NRS [numeric rating scale] ≥ 7). Hierarchical linear regression analysis also performed to identify factors associated with pain intensity (0 to 10 NRS). Results Multivariate logistic analyses revealed older age (OR [odds ratio] = 1.017, 95% CI [confidence interval] 1.001–1.032, P = 0.034), high anxiety level (OR = 1.162, 95% CI 1.020–1.324, P = 0.024), high pain catastrophizing (OR = 1.043, 95% CI 1.007–1.081, P = 0.018), and severe insomnia (OR = 1.112, 95% CI 1.057–1.170, P

Pain catastrophizing is becoming increasingly recognized as a clinically important psychological factor in chronic musculoskeletal pain. In this retrospective cross-sectional study, we have identified factors associated with an increased risk for pain catastrophizing in chronic neck pain (CN

BACKGROUND: Cervical epidural steroid injections are often used to treat acute and chronic pain syndromes involving the face, neck, and upper extremities. Ultrasound has evolved as a valuable tool for performing neuraxial blocks, providing useful prepuncture information on the structure. Our goal was to evaluate the accuracy and precision of ultrasound by comparing skin to dura distance from ultrasound with the actual skin to epidural depth. METHODS: We enrolled 50 patients undergoing cervical epidural blocks at the pain clinic. Ultrasound images with transverse and longitudinal median views of the C6/7 area were taken. The epidural needle was inserted, reproducing the direction of the ultrasound beam on the longitudinal median view. Measured distances from skin to dura on each ultrasound view were compared with the actual needle depth. Additionally, we examined ultrasound visibility, the number of puncture attempts, and any complications related to the procedure. RESULTS: Concordance correlation coefficients between the measured distances on ultrasound and actual needle depth were 0.9272 and 0.9268 on transverse and longitudinal median view, respectively. The cervical epidural block was successfully performed on 48 patients (96%). There were two incidents (4%) of dural puncture. No bloody taps, postprocedure complications, or hemodynamic instability related to cervical epidural blocks occurred. CONCLUSIONS: Ultrasound provides very accurate information on the skin to dura distance for epidural blocks in the cervical spine. Knowledge of skin to dura distance and a preview of spinal anatomy before puncture can more safely identify the epidural space.

Distinction between neuropathic pain and nociceptive pain helps facilitate appropriate management of pain; however, diagnosis of neuropathic pain remains a challenge. The aim of this study was to develop a Korean version of the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain scale and assess its reliability and validity. The translation and cross-cultural adaptation of the original LANSS pain scale into Korean was established according to the published guidelines. The Korean version of the LANSS pain scale was applied to a total of 213 patients who were expertly diagnosed with neuropathic (n = 113) or nociceptive pain (n = 100). The Korean version of the scale had good reliability (Cronbach's α coefficient = 0.815, Guttman split-half coefficient = 0.800). The area under the receiver operating characteristic curve was 0.928 with a 95% confidence interval of 0.885-0.959 (P < 0.001), suggesting good discriminate value. With a cut-off score ≥ 12, sensitivity was 72.6%, specificity was 98.0%, and the positive and negative predictive values were 98% and 76%, respectively. The Korean version of the LANSS pain scale is a useful, reliable, and valid instrument for screening neuropathic pain from nociceptive pain.

Background and Objectives For diagnostic lumbar medial-branch blocks, fluoroscopic guidance is considered mandatory, but this technique comes with radiation exposure. The clinical feasibility of the ultrasound-guided lumbar medial-branch block has been demonstrated. We evaluated the success rate and validity of this new method by use of fluoroscopy controls in patients previously diagnosed with lumbar facet joint–mediated pain. Methods In 20 patients, 101 lumbar medial-branch blocks were performed under ultrasound guidance. The target point was the groove at the cephalad margin of the transverse process adjacent to the superior articular process. C-arm fluoroscopy was performed afterward to confirm the needle position. Pain scores were assessed by use of visual analog scale (VAS 0 to 100). Results All 101 needles were placed in the correct lumbar segment. Ninety-six of the 101 needletips were in the correct position with a success rate of 95%. Two needles were associated with intravascular spread of the contrast dye. VAS score was reduced from 52 to 16 after the block. Conclusions Ultrasound-guided lumbar medial-branch blocks can be performed with a high success rate. However, to be completely independent from fluoroscopy controls, this technique requires further studies regarding the detection of intravascular spread.

Artemin is a glial cell line-derived neurotrophic factor (GDNF) that supports survival of cultured sensory neurons. The trophic effect of artemin on sensory neurons and the restricted expression of artemin receptor GFR-α3 to nociceptive sensory neurons suggest that artemin might selectively impact the physiologic mechanisms that mediate changes associated with the neuropathic pain state or stimulate post-traumatic axonal growth. We have used an in vitro isolated dorsal root ganglia cells to study the effects of artemin on adult rat neuronal system and performed a microarray experiment. We found that 285 genes were differentially regulated by artemin for a 3-h treatment, including genes related to cell adhesion, transport activity and catalytic activity. A set of genes involved in regulation of actin dynamics including Wiskott–Aldrich syndrome protein (WASP) interacting protein, cofilin and dynamin were downregulated by artemin, suggesting a previously undefined role in the regulation of synaptic vesicle movement. This transcriptional program initiated by artemin was functionally relevant to the synaptic vesicle exocytosis and reuptake. Artemin also downregulated the expression of genes related to cell adhesion, matrix assembly and cellular migration including biglycan, plectin, nestin, neuronatin and neuron-glia-CAM-related cell adhesion molecule, which might be relevant to axonal elongation and lamellipodia formation in DRG neuron.

We studied the effects of intrathecal administration of an N-methyl-D-aspartate (NMDA) receptor antagonist and an antagonist of the glycine site of the NMDA receptor on the minimum alveolar anaesthetic concentration (MAC) of isoflurane in rats, and on locomotor activity in conscious rats. In Wistar rats fitted with indwelling intrathecal catheters, we determined the MAC of isoflurane after the administration of saline (control group); the competitive NMDA receptor antagonist 3-(2-carboxypiperazin-4-yl)pro-pyl-1-phosponic acid(CPP) at 0.01, 0.1, and 1.0 nM; and the selective antagonist of the glycine site on the NMDA receptor complex 7-chlorokynurenic acid (7CKA) at 0.1, 1.0, and 10 nM. After measurement of MAC following administration of the antagonist, the equipotent reversal dose of NMDA or D-serine was administered. The rats were examined for the presence of locomotor dysfunction by intrathecal administration of NMDA receptor antagonists, NMDA and D-serine in conscious rats. All of the experiments were performed using randomization and masking of drugs. CPP at 0.1 and 1.0 nM decreased the MAC of isoflurane by 9.9–17.6% (P < 0.05). 7CKA at 1.0 and 10 nM reduced MAC from 10.5–15.5% (P < 0.05). Intrathecal administration of NMDA or D-serine reversed the decreases in MAC to control values. Locomotor activity was not changed. We believe that NMDA receptor plays an important role in determining the MAC of isoflurane in the spinal cord.

The ability to identify the correct vertebral level through examination is an important skill for clinicians who are performing nerve blocks without fluoroscopy. The conventional palpation method, which identifies the most prominent cervical spinous process as the seventh cervical (C7) spinous process is unreliable in many cases. We compared the accuracy of 2 different palpation methods used for identifying C7.Ninety-six patients scheduled for cervical spine procedures under fluoroscopy guidance were randomized into either the control group or the flexion-extension group. The control group was examined with the conventional method, and the flexion-extension group was examined through assisted flexion and extension of the patient's cervical spine and identifying the lowest freely moving spinous process as C6 and the following stationary cervical spinous process as C7. A single anesthesiologist attempted to identify the C7 spinous process by using either the conventional method or the flexion-extension method and marked the presumed C7 spinous process with a radiopaque indicator. The actual vertebral level was then confirmed by fluoroscopy. The accuracy of the 2 different palpation techniques was compared, and the influence of patients' age, gender, and body mass index (BMI) was also examined.The C7 spinous process was correctly identified in 77.1% of patients in the flexion-extension group, compared with 37.5% in the control group (P0.001). The C6 spinous process was identified as the most prominent cervical spinous process instead of C7 in 47.9% of patients in the control group, showing that errors are more common in the cephalad direction with the conventional method. The accuracy of the flexion-extension method was significantly higher than the conventional method regardless of the patient's age, gender, and BMI. Particularly, this difference in accuracy was seen not only in patients with a BMI25 kg/m(2), but also in those with a BMI ≥25 kg/m(2) (BMI25 kg/m(2), P=0.006 vs BMI ≥25 kg/m(2), P=0.008).The flexion-extension method is more accurate than the conventional method when identifying cervical vertebral level.

The purpose of this study was to determine the efficacy of treatment with anti-tumor necrosis factor (TNF) antibody in preventing the deleterious effects of endotoxin. Polyclonal anti-TNF antibody was produced by immunizing rabbits. Experiments were carried out on 16 rabbits intravenously infused with the lethal dose of lipopolysaccharide (LPS). Pretreatment with anti-TNF antibody resulted in protection from the development of hypotension and metabolic acidosis. The serum TNF level was significantly depressed in the antibody-pretreated group. Eighty-eight percent in the anti-TNF antibody-pretreated rabbits survived more than 48 h, whereas none of the rabbits who were given LPS alone survived over 24 h (LPS group). Prominent histopathological changes in the liver and kidney were evident in the LPS group. In contrast, pathologic changes in the tissue from the anti-TNF antibody group were considerably less prominent. These results support the idea that TNF plays a central role in mediating the pathophysiologic changes during endotoxin shock.

Twelfth rib syndrome is thought to be due to intercostal nerve irritation by a mobile twelfth rib, and presents with upper abdominal pain, or low thoracic pain. This syndrome appears to be a fairly common entity and diagnosis is based on clinical findings. Patients with twelfth rib syndrome can be misdiagnosed when it has been overlooked. We report a case of a 34-year-old male along with a presentation of twelfth rib syndrome. One patient was transferred from urologic clinic to pain clinic due to right flank pain and admitted. The patient had direct tenderness on twelfth rib area and direct tenderness was reproducible. Pain increased when the patient flexed laterally, rotated trunk. There were no specific abnormal findings in laboratory test, electrocardiogram, and radiologic examination. After intercostal nerve block and epidural block, pain decreased and the patient was discharged.