Hue Jung Park

Pharmacologic Management of Chronic Pain

Chronic pain is a multifactorial condition with both physical and psychological symptoms, and it affects around 20% of the population in the developed world. In spite of outstanding advances in pain management over the past decades, chronic pain remains a significant problem. This article provides a mechanism- and evidence-based approach to improve the outcome for pharmacologic management of chronic pain. The usual approach to treat mild to moderate pain is to start with a nonopioid analgesic. If this is inadequate, and if there is an element of sleep deprivation, then it is reasonable to add an antidepressant with analgesic qualities. If there is a component of neuropathic pain or fibromyalgia, then a trial with one of the gabapentinoids is appropriate. If these steps are inadequate, then an opioid analgesic may be added. For moderate to severe pain, one would initiate an earlier trial of a long term opioid. Skeletal muscle relaxants and topicals may also be appropriate as single agents or in combination. Meanwhile, the steps of pharmacologic treatments for neuropathic pain include (1) certain antidepressants (tricyclic antidepressants, serotonin and norepinephrine reuptake inhibitors), calcium channel α2-δ ligands (gabapentin and pregabalin) and topical lidocaine, (2) opioid analgesics and tramadol (for first-line use in selected clinical circumstances) and (3) certain other antidepressant and antiepileptic medications (topical capsaicin, mexiletine, and N-methyl-d-aspartate receptor antagonists). It is essential to have a thorough understanding about the different pain mechanisms of chronic pain and evidence-based multi-mechanistic treatment. It is also essential to increase the individualization of treatment.

Ganglion Impar Block With Botulinum Toxin Type A for Chronic Perineal Pain -A Case Report-

Chronic perineal pain is an often encountered problem, which produces a great degree of functional impairment and frustration to the patient and a challenge to the treating physician. The reason for this problem is that the region contains diverse anatomic structures with mixed somatic, visceral and autonomic innervations affecting bladder and bowel control and sexual function. A blockade of nociceptive and sympathetic supply to the perineal region, supplied through the ganglion impar has been shown to benefit patients with chronic perineal pain. Several options to this block have been described that chemical neurolysis, radiofrequency ablation etc. Although the analgesic effect of Botulinum toxin type A (BoNT-A) has long been considered secondary to its action for muscle relaxation, BoNT-A also affects the release of the neurotransmitters that are involved in pain perception. We describe a patient who was successfully given ganglion impar block with BoNT-A.

Rates of lumbosacral transforaminal injections interpreted as intravascular: fluoroscopy alone or with digital subtraction

We investigated the rate of injections interpreted as intravascular during imaging of lumbosacral transforaminal epidural injections, using fluoroscopy alone or with digital subtraction. We evaluated 732 injections performed on 348 patients: 8.1% (59/732) and 10.5% (77/732) of injections were interpreted as intravascular during fluoroscopy and digital subtraction, respectively, p = 0.13. The odds ratio (95% CI) for interpreting injections as intravascular increased for both fluoroscopy and digital subtraction fluoroscopy, with: each year of age, 1.04 (1.01–1.07) and 1.03 (1.00–1.06), p = 0.011 and 0.024, respectively; sacral compared with lumbar injections, 10 (5–19) and 8 (5–15), p < 0.001 for both. The odds ratio for intravascular injection increased with three other variables during digital subtraction fluoroscopy: spinal stenosis, 5.1 (1.5–17.1), p = 0.009; failed back surgery syndrome, 4.3 (1.2–15.8), p = 0.025; compression fracture, 8.0 (1.6–39.4), p = 0.011.

Sacral Nerve Stimulation for Treatment of Chronic Intractable Anorectal Pain -A Case Report-

Despite recent methodological advancement of the practical pain medicine, many cases of the chronic anorectal pain have been intractable. A 54-year-old female patient who had a month history of a constant severe anorectal pain was referred to our clinic for further management. No organic or functional pathology was found. In spite of several modalities of management, such as medications and nerve blocks had been applied, the efficacy of such treatments was not long-lasting. Eventually, she underwent temporary then subsequent permanent sacral nerve stimulation. Her sequential numerical rating scale for pain and pain disability index were markedly improved. We report a successful management of the chronic intractable anorectal pain via permanent sacral nerve stimulation. But further controlled studies may be needed.

Ultrasound-guided pulsed radiofrequency treatment of the cervical sympathetic chain for complex regional pain syndrome: A retrospective observational study.

Abstract The stellate ganglion is a common target to manage neuropathic pain in the upper extremities. However, the effect duration of a single stellate ganglion block is often temporary. To overcome the short-term effects of a single sympathetic block, pulsed radiofrequency (PRF) can be applied. The aim of the present study was to investigate the efficacy of PRF on the cervical sympathetic chain under ultrasound guidance for complex regional pain syndrome (CRPS). Twelve CRPS patients who underwent PRF on the cervical sympathetic chain were enrolled in this retrospective analysis. Under ultrasound guidance, PRF was performed for 420u200aseconds at 42°C on the C6- and C7-level sympathetic chain. The pain intensity decreased significantly at 1 week after the procedure. Overall, 91.7% of patients experienced at least moderate improvement. A positive correlation was observed between the extent of pain reduction at 1 week after PRF and the degree of overall benefit (ru200a=u200a0.605, Pu200a=u200a0.037). This reduction in symptoms was maintained for a mean of 31.41u200a±u200a26.07 days after PRF. There were no complications associated with this procedure. PRF on the cervical sympathetic chain, which can be performed easily and safely under ultrasound guidance, should be considered an option for managing CRPS of the upper extremities.

Comparison of efficacy of continuous epidural block and pulsed radiofrequency to the dorsal root ganglion for management of pain persisting beyond the acute phase of herpes zoster

Background There is little evidence regarding the effectiveness of intervention methods in the treatment of zoster-related pain (ZAP) after the acute phase of zoster. Generally, if ZAP remains after more than 180 days from its onset, the likelihood of pain reduction is very low; this condition is considered as a “well established” post-herpetic neuralgia (PHN). Although the clinical efficacy of intrathecal steroid injection and spinal cord stimulation (SCS) for ZAP management has been reported, these interventions are not widely used due to inherent disadvantages. Continuous epidural block is widely used in clinical practice, and the effectiveness of pulsed radiofrequency (PRF) to the dorsal root ganglion (DRG) in the treatment of ZAP already has been reported. Objectives The purpose of this study was to compare the clinical efficacy of continuous epidural block and DRG PRF beyond acute phase of zoster, bur before PHN was well established (from 30 days to180 days after zoster onset). Study design Retrospective comparative study. Methods A total of 42 medical records were analyzed. Patients were divided into two groups according to the type of procedure utilized: continuous epidural block (continuous epidural group) and DRG PRF (PRF group). The clinical efficacy of the procedure was evaluated using a numeric rating scale (NRS) and the medication dose before and 1 to 6 months after the procedure. Results There was a significant decrease in the NRS value with time in both groups. However, this decrease was more significant in the PRF group than in the continuous epidural group. The medication doses decreased significantly in the PRF group over time, but not in the continuous epidural group. The rate of clinically meaningful PHN (NRS≥3) was also lower in the PRF group than in the continuous epidural group. Conclusions This study revealed that DRG PRF was more effective than a continuous epidural block in treating ZAP after the acute phase of zoster. A neuromodulation method such as DRG PRF may be a useful option for reducing the progression of neuropathic changes caused by the persistent transmission of a pain signal after the acute phase of zoster.

Clinical efficacy of transforaminal epidural injection for management of zoster-associated pain: a retrospective analysis

ObjectivesTransforaminal epidural injection (TFEI) has superior accessibility to the dorsal root ganglion, which is an essential location of pain signaling in herpes zoster. However, the effectiveness of TFEI for herpes zoster patients has not previously been studied. We retrospectively analyzed the efficacy of TFEI for pain control and prevention of PHN in patients with acute and subacute herpes zoster.MethodsMedical records of 137 patients who underwent TFEI for zoster-associated pain (ZAP) were reviewed. The participants were divided into two groups: acute TFEI group (TFEI within 30xa0days after zoster) and subacute TEEI group (TFEI between 30 and 90xa0days). The efficacy of TFEI was assessed by a numerical rating scale (NRS), doses of medications, and time to relief of ZAP. Incidence of PHN at 1xa0week to 6xa0months after TFEI was evaluated.ResultsTime to ZAP relief was significantly shorter and the incidence of PHN was significantly lower in the acute TFEI group than in the subacute TFEI group. Rate of medication discontinuation was significantly higher in the acute TFEI group than in the subacute TFEI group.ConclusionsEarly application of TFEI in the acute phase of zoster can be a useful option for ZAP control and prevention of chronic neuropathic pain such as PHN.

Clinical effect of the proximity of epidural blood patch injection to the leakage site in spontaneous intracranial hypotension

Abstract Background: Epidural blood patch (EBP) has been shown to be an effective treatment option for spontaneous intracranial hypotension (SIH). We investigated whether response to the EBP was related to the distance of the injection site from the leakage site in patients with SIH. Methods: We reviewed patients with SIH who underwent EBP at a single hospital. Patients were assigned to group R (response after EBP) or group N (no response after EBP). We then analyzed the demographics, clinical characteristics, leakage site, leakage length, EBP injection level and distance from leakage site, and injected EBP volume. Results: Sixty-two patients were included in the analysis. The overall response rate to EBP was 59.7% (37 patients). The leakage length and injection distance from the leakage site did not differ between the two groups. Age, gender, body mass index, leakage site, and EBP volume did not differ significantly between the two groups. Conclusion: The clinical effect of EBP in SIH was not affected by leakage length or injection distance to leakage site. Further large studies must be conducted to investigate the efficacy of targeted EBP for SIH.

Guidelines for prescribing opioids for chronic non-cancer pain in Korea

As the treatment of chronic non-cancer pain gradually increases, clinicians have more opportunities to encounter opioid prescription. However, guidelines for prescribing opioids for chronic non-cancer pain have never been published in Korea. The present guidelines were prepared by reviewing various research data. In cases in which the data were insufficient, recommendations were presented following discussion among experts affiliated with the Opioids Research Group in the Korean Pain Society. The present guidelines may need to be continuously revised and amended as more clinical evidence is acquired.

The influence of epidural catheter on the incidence of intravascular injection during caudal block

ObjectiveThe aim of this study was to analyze the influence of epidural catheters on the incidence of intravascular injection and to identify possible predictors of intravascular injection in patients undergoing a caudal block using fluoroscopy.MethodsA total of 154 patients scheduled to receive a caudal block were randomized into group N (those without epidural catheter) or group C (those with epidural catheter). Demographic and clinical data were recorded and analyzed.ResultsThe incidence of intravascular injection was 15.6% in group N, 6.5% in group C, and 11.0% overall, without statistical differences between the two groups (Pxa0=xa00.105). Univariate analysis revealed that blood at hub (Pxa0=xa00.047) and positive aspiration test (Pxa0=xa00.045) were more frequently observed in group N than in group C. Quality of analgesia was significantly higher in group C than in group N (Pxa0=xa00.029). Multivariate analysis identified older age (Pxa0=xa00.024), blood at hub (Pxa0=xa00.003), and positive aspiration test (Pxa0=xa00.001) as predictors of intravascular injection.ConclusionsIn this study, while the incidence of intravascular injection during caudal blocks was less frequent with epidural catheter use, it was not statistically significant. However, a caudal block using an epidural catheter provided a lower incidence of blood at hub, fewer positive aspiration tests, and superiority in pain improvement.