Association between Chronic Pain and Alterations in the Mesolimbic Dopaminergic System

Chronic pain (pain lasting for >3 months) decreases patient quality of life and even occupational abilities. It can be controlled by treatment, but often persists even after management. To properly control pain, its underlying mechanisms must be determined. This review outlines the role of the mesolimbic dopaminergic system in chronic pain. The mesolimbic system, a neural circuit, delivers dopamine from the ventral tegmental area to neural structures such as the nucleus accumbens, prefrontal cortex, anterior cingulate cortex, and amygdala. It controls executive, affective, and motivational functions. Chronic pain patients suffer from low dopamine production and delivery in this system. The volumes of structures constituting the mesolimbic system are known to be decreased in such patients. Studies on administration of dopaminergic drugs to control chronic pain, with a focus on increasing low dopamine levels in the mesolimbic system, show that it is effective in patients with Parkinson's disease, restless legs syndrome, fibromyalgia, dry mouth syndrome, lumbar radicular pain, and chronic back pain. However, very few studies have confirmed these effects, and dopaminergic drugs are not commonly used to treat the various diseases causing chronic pain. Thus, further studies are required to determine the effectiveness of such treatment for chronic pain.

3D printing technology applied to orthosis manufacturing: narrative review

Recently, three-dimensional (3D) printing technology has gradually been applied to the field of orthoses. This narrative review aimed to investigate the effect of 3D printed orthoses compared to conventional orthoses (non-3D printed orthoses). We searched MEDLINE for articles published up to July 27, 2020, and the main search phrases for identifying related articles were "3D printed orthosis", "3D printed orthoses", "3D printed braces", "3D printed splints", "3D printing orthosis", "3D printed orthoses", "3D printing braces" and "3D printing splints". We included articles that applied 3D printed orthoses to patients or healthy participants and excluded those not written in English, conference abstracts or presentations, and reviews. A total of 237 papers were identified, and qualifications were evaluated based on the title, abstract, and full text. A total of 22 articles were finally included in the analysis. The 3D printed orthoses showed similar or superior effects on biomechanical parameters and kinematic parameters such as wrist-hand function, wrist spasticity, arch height index, foot plantar pressure, and joint range of motion (ROM). In addition, 3D printed orthoses had high satisfaction and comfort compared to conventional orthoses. We believe that 3D printed orthoses can replace conventional ones, and they are expected to gain more popularity in the future.

Understanding the different physical examination tests for suspected meniscal tears

Meniscal tears are common in sport medicine practice. Many articles and textbooks discuss the relative validity of the different components of the physical examination with respect to their sensitivity, specificity, and positive/negative predictive values as if they were diagnostic tests. In this article, we demonstrate why this approach is limited, including the heterogeneous nature of meniscal tear pathology (e.g., posterior vs anterior). Therefore, in this article, we categorize all the published tests in the literature with regards to the mechanism underlying a positive test. We believe our approach provides the clinician with additional tools to diagnose tears. Future research should explore predictive models based on the different components accounting for heterogeneous pathology and different patient contexts.

Effect of Diabetes on Post-stroke Recovery: A Systematic Narrative Review

Background: Patients with stroke often have comorbid diabetes. Considering its detrimental effects on brain function, diabetes may increase the risk of poor recovery. Methods: The aim of this review was to investigate the effect of diabetes on post-stroke recovery by a systematic review. Several specific aspects of post-stroke recovery, including activities of daily living (ADL), motor, cognitive, and quality of life (QOL) recovery, were examined. We searched the PubMed, SCOPUS, Embase, and Cochrane Library databases for relevant studies on the effect of diabetes on post-stroke recovery, published until May 26, 2021. A total of 52,051 potentially relevant articles were identified. After reading the titles and abstracts and assessing their eligibility based on full-text articles, 34 publications were included in this review. Results: Of 29 studies that assessed ADL recovery after stroke, 22 studies suggested that diabetes had a negative effect on recovery of ADL after stroke. Regarding motor recovery, only one out of four studies showed that diabetes had some effect on motor recovery after stroke. Of the two studies on cognitive recovery, one reported that diabetes was an independent predictor of poor cognitive recovery after stroke. Three studies on QOL reported that a poor QOL after stroke was associated with the presence of diabetes. Conclusions: The current review suggests that the post-stroke recovery of ADL seems to be poorer in patients with diabetes than patients without diabetes. Further, there are insufficient data to conclude the effect of diabetes on motor and cognitive recovery, but it may have some influence on the quality of life after stroke. Systematic Review Registration: doi: 10.37766/inplasy2021.11.0032, identifier: INPLASY2021110032.

The Effectiveness of Pulsed Radiofrequency on Joint Pain: A Narrative Review

BACKGROUND

Pulsed radiofrequency (PRF) stimulation has been safely and effectively applied for controlling various types of pain.

PURPOSE

We reviewed the literature on the efficacy of PRF for controlling pain in joint disorders.

METHODS

We searched PubMed for papers published prior to September 7, 2019, that used PRF to treat pain due to joint disorders. The key search phrases for identifying potentially relevant articles were (PRF AND joint) OR (PRF AND arthritis) OR (PRF AND arthropathy). The following inclusion criteria were applied for the selection of articles: (1) patients' pain was caused by joint disorders; (2) PRF stimulation was applied to manage joint-origin pain; and (3) after PRF stimulation, follow-up evaluation was performed to assess the reduction in pain intensity. Moreover, joints with more than 3 reported PRF studies were included in our review.

RESULTS

The primary literature search yielded 141 relevant papers. After reading their titles and abstracts and assessing their eligibility based on the full-text articles, we finally included 34 publications in this review. Based on the positive therapeutic outcomes of previous studies, PRF stimulation seems to be an effective treatment for cervical and lumbar facet, sacroiliac, knee, and glenohumeral joint pain. PRF appears to be beneficial. For confirmation of the effectiveness of PRF on joint pain, more high-quality studies are needed.

CONCLUSIONS

Our review provides insights on the degree of evidence according to pain in each joint, which will help clinicians make informed decisions for using PRF stimulation in various joint pain conditions.

Effect of Repetitive Transcranial Magnetic Stimulation on Post-stroke Dysphagia: A Meta-analysis of Stimulation Frequency, Stimulation Site, and Timing of Outcome Measurement

Dysphagia is one of the most frequent sequelae of stroke. It can result in various complications such as malnutrition, dehydration, aspiration pneumonia, and poor rehabilitation outcomes. Repetitive transcranial magnetic stimulation (rTMS) has been reported to improve dysphagia after a stroke; however, effective treatment protocols have not been established yet. We evaluated the effect of the following rTMS parameters on post-stroke dysphagia: stimulation frequency [high frequency (≥ 3 Hz) or low frequency (1 Hz)] and stimulation site (ipsilesional or contralesional mylohyoid cortex). Outcomes were measured immediately, at 3 weeks, and at 4 weeks after the rTMS session. The PubMed, SCOPUS, Embase, and Cochrane Library databases were systematically searched for relevant studies published between January 01, 1980, and December 13, 2021. Randomized controlled trials on the effects of rTMS on post-stroke dysphagia were included. Six studies were finally included in the analysis. The selected studies included 158 patients (rTMS group: 81 patients; sham group: 77 patients). Regarding the effect of high-frequency rTMS on the ipsilesional cortex, the standardized swallowing assessment (SSA) scores showed significant improvement after rTMS sessions immediately and at 4 weeks [immediate: P = 0.02, standard mean difference (SMD) =  - 0.61, 95% confidence interval (CI) =  - 1.14 to - 0.08; 4 weeks: P = 0.006, SMD =  - 0.74, 95% CI =  - 1.27 to - 0.21]; however, there was no significant reduction in the Penetration-Aspiration Scale (PAS) scores between the rTMS and sham groups (immediate: P = 0.43, SMD = 0.25, 95% CI =  - 0.36, 0.86; 3 weeks: P = 0.39, SMD = 0.37, 95% CI =  - 0.47 to 1.22). After low-frequency rTMS on the ipsilesional cortex, a significantly greater improvement in the SSA scores was found in the rTMS group than in the sham group, both immediately and at 4 weeks after rTMS sessions (immediate: P = 0.03, SMD =  - 0.59, 95% CI =  - 1.12 to - 0.06; 4 weeks: P = 0.001, SMD =  - 0.92, 95% CI =  - 1.48 to - 0.37). In addition, immediately after the rTMS sessions, the PAS scores were significantly reduced in the rTMS group than in the sham group (P = 0.047, SMD =  - 0.60, 95% CI =  - 1.19 to - 0.01). However, at 4 weeks after rTMS sessions, there was no significant reduction in the PAS scores in the rTMS group compared to the sham group (P = 0.48, SMD =  - 0.19, 95% CI =  - 0.71 to 0.33). Both high-frequency rTMS of the ipsilesional cortex and low-frequency rTMS of the contralesional cortex improved some measurements of the swallowing function in stroke patients immediately and at 4 weeks after treatment.

Use of Pulsed Radiofrequency for the Treatment of Discogenic Back Pain: A Narrative Review

BACKGROUND

Low-back pain (LBP) is one of the most frequently reported symptoms of patients who visit pain clinics, and a significant proportion of them have discogenic pain. Pulsed radiofrequency (PRF) stimulation is an effective treatment for various types of pain.

PURPOSE

We reviewed articles which investigated the effectiveness of intradiscal PRF for controlling discogenic LBP.

METHODS AND MATERIALS

We searched PubMed for papers published prior to August 7, 2020, in which intradiscal PRF was used for treating discogenic LBP. The key search phrase was (intradiscal PRF) for identifying potentially relevant articles. We included articles in which intradiscal PRF was used for controlling LBP. Review articles were excluded.

RESULTS

Nine publications were included in this review. Except for one study, all other studies showed positive therapeutic outcomes after treating discogenic LBP using intradiscal PRF. However, the quality of these studies was not high.

CONCLUSIONS

This review showed that intradiscal PRF appears to be a helpful treatment method for patients with discogenic LBP. Our review provides insights into the degree of evidence of the therapeutic effects of intradiscal PRF for alleviating discogenic LBP. For confirmation of the effectiveness of intradiscal PRF on discogenic LBP, more high-quality studies are necessary.

Injury of Corticospinal tract and Corticoreticular pathway caused by high-voltage electrical shock: a case report

BACKGROUND

We imaged the corticospinal tract (CST) and corticoreticular pathway (CRP) using diffusion tensor tractography (DTT) to evaluate the cause of muscle weakness in a patient who was exposed to high-voltage electricity.

CASE PRESENTATION

A 39-year-old man presented with quadriparesis after high-voltage electrical shock from power lines while working about 5.8 years ago. The electrical current entered through the left hand and exited through the occipital area of the head. The degree of weakness on bilateral upper and lower extremities was 3-4 on the Medical Research Council strength scale. Diffusion tensor imaging (DTI) was performed 5.8 years after onset. The CST and CRP were depicted by placing two regions of interest for each neural tract on the two-dimensional fractional anisotropy color map. DTT of the DTI scan showed that the bilateral CST and CRP were thinned compared to those of the healthy control subject. On the nerve conduction test, abnormal findings suggesting peripheral nerve lesion were not observed. Therefore, injury of bilateral CST and CRP seems to have contributed to our patient's weakness after the electrical shock.

CONCLUSION

Depiction of neural tracts in the brain using DTT can assist in the accurate and detailed evaluation of the cause of neural deficit after electrical injury.

Segmental Spinal Myoclonus After a Cervical Transforaminal Epidural Steroid Injection

In clinical practice, cervical transforaminal epidural steroid injection is commonly used for alleviating pain. We report a case of segmental spinal myoclonus that developed after cervical transforaminal local anesthetic and steroid injection. A 39-yr-old man presented involuntary movements of the bilateral upper trapezius muscles after cervical transforaminal epidural steroid injection on the right C6 and C7 roots with a 5 mg of dexamethasone injectate mixed with 0.5 ml of 1% lidocaine and 0.5 ml of normal saline at each level. His myoclonus was semirhythmic and continuously persisted at a frequency of approximately 30 episodes per minute. The myoclonus continued even at rest and during sleep. In addition, it was resistive to stimulus, such as touch and voluntary action. Based on the clinical features, the patient was diagnosed as having a segmental spinal myoclonus. Clonazepam 0.25 mg was administered three times daily. The myoclonus gradually improved and resolved completely within 2 wks. Segmental spinal myoclonus is one of rare complications after cervical transforaminal epidural steroid injection. Clinicians should be aware of the likelihood of this potential complication.

Treatment of Upper Crossed Syndrome: A Narrative Systematic Review

BACKGROUND AND OBJECTIVES

Upper crossed syndrome (UCS) is a common musculoskeletal condition that is characterized by tightness and weakness of the muscles of the neck, shoulders, and upper back. The aim of this current study is to summarize and provide an overview of the treatment in patients with UCS.

MATERIALS AND METHODS

A MEDLINE (PubMed), Cochrane library, Embase, Scopus, and Web of Science database search was conducted for English-language articles about upper crossed syndrome that were published until 19 January 2023. To identify potentially relevant articles, the following key search phrases were combined: "upper crossed syndrome", "upper cross syndrome", "diagnosis", and "treatment". A total of 233 articles were identified. After reading the titles and abstracts and assessing their eligibility based on the full-text articles, 11 articles were finally included in this review. The risk of bias (RoB) was assessed using RoB-2 and ROBINS-I for the randomized controlled trials (RCTs) and the non-randomized clinical trial (non-RCT), respectively.

RESULTS

Among eleven studies that investigated the effect of treatment programs for UCS, five studies compared the therapeutic effect of exercise programs with controls, whereas six compared different rehabilitative treatment strategies, such as the muscle energy technique, soft-tissue mobilization, and stretching exercises. In addition, regarding the study design, ten studies were RCTs and only one study was a prospective observational study.

CONCLUSIONS

Treatment programs including various types of exercises and techniques to correct an abnormal posture and restore neuromuscular imbalances are effective for decreasing pain and improving neck disabilities and postural deviations in patients with UCS.

Accuracy of Ultrasound-Guided Pudendal Nerve Block in the Ischial Spine and Alcock's Canal Levels: A Cadaveric Study

BACKGROUND

Blockade of the pudendal nerve (PN) using ultrasound (US) guidance has been described at the levels of the ischial spine and Alcock's canal. However, no study has been conducted to compare anatomical accuracy between different approaches in targeting the PN.

OBJECTIVE

To investigate the accuracy of US-guided injection of the PN at the ischial spine and Alcock's canal levels. This study also compared the accuracy of the infiltrations by three sonographers with different levels of experience.

SUBJECTS

Eight Thiel-embalmed cadavers (16 hemipelvises).

METHODS

Three physiatrists trained in musculoskeletal US imaging with 12 years, five years, and one year of experience performed the injections. Each injected a 0.1-mL bolus of colored dye in both hemipelvises of each cadaver at the ischial spine and Alcock's canal levels under US guidance. Each cadaver received three injections per hemipelvis. The accuracy of the injection was determined following hemipelvis dissection by an anatomist.

RESULTS

The injections were accurate 33 times out of the total 42 attempts, resulting in 78% accuracy. Sixteen out of 21 injections at the ischial spine level were on target (76% accuracy), while the approach at Alcock's canal level yielded 17 successful injections (81% accuracy). The difference between the approaches was not statistically significant. There was also no significant difference in accuracy between the operators.

CONCLUSIONS

US-guided injection of the PN can be performed accurately at both the ischial spine and Alcock's canal levels. The difference between the approaches was not statistically significant.

An unusual presentation of neuropathic pain following cervical spinal cord injury: a case report

BACKGROUND

We report a patient with unusual occipital neuropathic pain (at-level neuropathic pain) due to a small central cervical spinal cord injury (SCI).

CASE PRESENTATION

A 50-year-old man presented with severe bilateral occipital pain after falling from a height of 2 m, 2 weeks ago. The degree of pain was evaluated to be 9 out of 10 using the numeric rating scale (NRS). The nature of the pain was tingling, burning, and piercing, and hyperalgesia was present over the bilateral posterior head regions. Greater occipital nerve block with bupivacaine and dexamethasone was not effective. On axial T2-cervical magnetic resonance imaging (MRI), a focal high signal change was observed in the central portion of the spinal cord at the C2 level. We deliberated that the patient's pain was due to the SCI observed on MRI, and after administration of oral medications, the NRS pain score reduced from 9 to 2.

CONCLUSIONS

Neuropathic pain caused by SCI varies according to the location and degree of injury of the pain-related neural tracts; therefore, clinicians should closely observe the pain patterns and findings on imaging in patients with SCI to determine the cause of pain accurately.

Accuracy of Two Ultrasound-Guided Coracohumeral Ligament Injection Approaches: A Cadaveric Study

BACKGROUND

Glenohumeral idiopathic adhesive capsulitis is a common shoulder condition that hinders functionality. Addressing the pathology has been extensively researched. Ultrasound (US)-guided injections have shown their efficacy. However, no study has been conducted to compare anatomical accuracy between different approaches in targeting the coracohumeral ligament (CHL).

OBJECTIVE

To investigate whether US-guided injection of the CHL can be performed accurately using either the rotator interval (RI) or the coracoidal (CO) approach.

METHODS

An experimental cadaveric case series.

SETTING

Anatomy laboratory.

SPECIMENS

Both shoulders of 13 Thiel-embalmed cadavers.

INTERVENTIONS

Three physiatrists each injected a 0.1 mL bolus of colored dye in both shoulders of each cadaver using either the RI or the CO approach under US guidance. Each cadaver received a total of six injections (three injections per shoulder). The accuracy of the injection was determined following shoulder dissection by an anatomist.

MAIN OUTCOME MEASURE

The accuracy of the US-guided injection of the CHL.

RESULTS

The RI approach yielded 36 accurate injections, giving it an accuracy of 100%. With the CO approach two injections were deemed inaccurate yielding an accuracy of 94%. There was no significant difference in accuracy between all operators.

CONCLUSIONS

US-guided injection of the CHL can be performed accurately with both the RI and CO approaches. The RI approach was likely to be more accurate.

Severe acitretin-induced diffuse idiopathic skeletal hyperostosis: a case report

Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier-Rotes-Querol disease, is a systemic noninflammatory disease characterized by ossification of the entheses. DISH predominantly affects the spine. Although peripheral involvement is also often reported, it rarely affects patients' function. A 77-year-old man presented to our emergency department because of incapacitating pain and stiffness in the spine and hips. The patient had been diagnosed with biopsy-proven mycosis fungoides 3 years earlier and had been treated with oral acitretin at 25 to 50 mg daily since diagnosis. However, the patient gradually developed a severely limited range of motion in his spine and hips (left > right), significantly impairing his mobility and activities of daily living. Cervical and dorsolumbar radiographs showed extensive ossification along the anterior longitudinal ligament; this finding was compatible with DISH and had not been present in radiographs taken 3 years earlier. Pelvic radiographs showed multiple enthesophytes predominantly around the coxofemoral joints. DISH has been reported as a possible long-term adverse effect of acitretin. Despite optimal conservative treatment, the patient remained severely impaired and thus finally underwent extensive osteophyte excision and total hip replacement on the left side. His acitretin therapy was also stopped to prevent further progression of his DISH.

Accuracy of unguided and ultrasound guided Coracohumeral ligament infiltrations - a feasibility cadaveric case series

BACKGROUND

Coracohumeral ligament (CHL) thickening, contracture, and fibroplasia have been identified in glenohumeral idiopathic adhesive capsulitis (GHIAC). The CHL is the main structure responsible for the range of motion limitations. Favorable outcomes have been reported with CHL surgical release. Intra-articular glenohumeral joint corticosteroid infiltrations are utilized to disrupt the inflammatory process and reduce pain in GHIAC. The aim of this study was to investigate whether the CHL could be accurately targeted with a periligamentous infiltration.

METHODS

A convenience sample of 12 unembalmed cadaver shoulders (mean age: 74.5 years, range 66-87 years) without evidence of previous injury or surgery were utilized in this exploratory double factor feasibility cadaveric (unguided and ultrasound (US) guided) case series. Two clinicians trained in musculoskeletal infiltration techniques carried out the infiltrations on each shoulder with colored latex. One clinician infiltrated without guidance, the other with US-guidance. The injecting clinicians were blinded to the others infiltration procedure and the order was randomized. An anatomist blinded to the infiltration order performed a shoulder dissection and recorded the infiltrate location. Percentage calculation for accuracy of infiltration and a chi-square evaluation of the difference between unguided and US-guided infiltrations was applied.

RESULTS

An accuracy of 75% was achieved for unguided infiltration and 80% for US-guided infiltration techniques. Chi-squared indicated there was no significant difference (p = 0.82) between the unguided and US-guided techniques.

CONCLUSION

US-guided and unguided infiltrations achieved good accuracy targeting the CHL, suggesting infiltrations can specifically and accurately target the CHL. In vivo investigation using such infiltration techniques are warranted.